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Sample records for faint red sequence

  1. On the origin of the faint-end of the red sequence in high-density environments

    NASA Astrophysics Data System (ADS)

    Boselli, Alessandro; Gavazzi, Giuseppe

    2014-11-01

    With the advent of the new generation wide-field cameras it became possible to survey in an unbiased mode galaxies spanning a variety of local densities, from the core of rich clusters, to compact and loose groups, down to filaments and voids. The sensitivity reached by these instruments allowed to extend the observation to dwarf galaxies, the most "fragile" objects in the universe. At the same time models and simulations have been tailored to quantify the different effects of the environment on the evolution of galaxies. Simulations, models, and observations consistently indicate that star-forming dwarf galaxies entering high-density environments for the first time can be rapidly stripped from their interstellar medium. The lack of gas quenches the activity of star formation, producing on timescales of 1 Gyr quiescent galaxies with spectro-photometric, chemical, structural, and kinematical properties similar to those observed in dwarf early-type galaxies inhabiting rich clusters and loose groups. Simulations and observations consistently identify ram pressure stripping as the major effect responsible for the quenching of the star-formation activity in rich clusters. Gravitational interactions (galaxy harassment) can also be important in groups or in clusters whenever galaxies have been members since early epochs. The observation of clusters at different redshifts combined with the present high infalling rate of galaxies onto clusters indicate that the quenching of the star-formation activity in dwarf systems and the formation of the faint end of the red sequence is a very recent phenomenon.

  2. On the clustering of faint red galaxies

    NASA Astrophysics Data System (ADS)

    Xu, Haojie; Zheng, Zheng; Guo, Hong; Zhu, Ju; Zehavi, Idit

    2016-08-01

    Faint red galaxies in the Sloan Digital Sky Survey show a puzzling clustering pattern in previous measurements. In the two-point correlation function (2PCF), they appear to be strongly clustered on small scales, indicating a tendency to reside in massive haloes as satellite galaxies. However, their weak clustering on large scales suggests that they are more likely to be found in low-mass haloes. The interpretation of the clustering pattern suffers from the large sample variance in the 2PCF measurements, given the small volume of the volume-limited sample of such faint galaxies. We present improved clustering measurements of faint galaxies by making a full use of a flux-limited sample to obtain volume-limited measurements with an increased effective volume. In the improved 2PCF measurements, the fractional uncertainties on large scales drop by more than 40 per cent, and the strong contrast between small-scale and large-scale clustering amplitudes seen in previous work is no longer prominent. From halo occupation distribution modelling of the measurements, we find that a considerable fraction of faint red galaxies to be satellites in massive haloes, a scenario supported by the strong covariance of small-scale 2PCF measurements and the relative spatial distribution of faint red galaxies and luminous galaxies. However, the satellite fraction is found to be degenerate with the slope of the distribution profile of satellites in inner haloes. We compare the modelling results with semi-analytic model predictions and discuss the implications.

  3. Fainting

    MedlinePlus

    Fainting is a temporary loss of consciousness. If you're about to faint, you'll feel dizzy, ... at the same time, and may fall down. Fainting usually happens when your blood pressure drops suddenly, ...

  4. Fainting

    MedlinePlus

    ... muscle control at the same time, and may fall down. Fainting usually happens when your blood pressure drops suddenly, causing a decrease in blood flow to your brain. It is more common in older people. Some causes of fainting include Heat or dehydration ...

  5. Fainting

    MedlinePlus

    ... En Español Making a Change – Your Personal Plan Hot Topics Meningitis Choosing Your Mood Prescription Drug Abuse ... reasons why teens faint: Physical triggers. Getting too hot or being in a crowded, poorly ventilated setting ...

  6. Fainting

    MedlinePlus

    ... of fainting: Certain medicines, including those used for anxiety, depression, and high blood pressure (these drugs may cause a drop in blood pressure) Drug or alcohol use Hyperventilation Low blood sugar Seizures Sudden drop in blood pressure (such as ...

  7. Fainting

    MedlinePlus

    ... brain does not get enough oxygen. You lose consciousness, or "pass out," for a brief time (usually ... Taking longer than a few seconds to regain consciousness Fainting when you turn your head to the ...

  8. NOTE: Red, Gray, and Blue: Near Infrared Spectrophotometry of Faint Moons of Uranus and Neptune

    NASA Astrophysics Data System (ADS)

    Trilling, David E.; Brown, Robert H.

    2000-11-01

    Using the CoCo Cold Coronagraph at NASA's Infrared Telescope Facility on Mauna Kea, we observed the uranian satellites Miranda, Puck, Portia, and Rosalind and the neptunian satellite Proteus in the near infrared (JHK) to determine the albedos of those faint satellites. In V-J, all of Puck, Portia, Rosalind, and Proteus are very blue, similar to the colors of many icy satellites and of water ice. The satellites we observed have a wide range of J-H colors, with Miranda being blue, Proteus being gray, and Puck, Portia, and Rosalind being red. For the satellites for which we could determine H-K (Miranda, Puck, and Proteus), the colors are gray to red. As a whole, spectrally, these five satellites lie between icy Solar System satellites (e.g., saturnian satellites or the major uranian satellites) and Kuiper belt objects. The redness of Proteus and Puck and perhaps other satellites suggests the presence of organic material, although the redness is also similar to that of C- and D-class asteroids and some outer jovian moons. In all cases, diagnostic spectral features could be masked by broadband photometry.

  9. The accelerated build-up of the red sequence in high-redshift galaxy clusters

    NASA Astrophysics Data System (ADS)

    Cerulo, P.; Couch, W. J.; Lidman, C.; Demarco, R.; Huertas-Company, M.; Mei, S.; Sánchez-Janssen, R.; Barrientos, L. F.; Muñoz, R. P.

    2016-04-01

    We analyse the evolution of the red sequence in a sample of galaxy clusters at redshifts 0.8 < z < 1.5 taken from the HAWK-I Cluster Survey (HCS). The comparison with the low-redshift (0.04 < z < 0.08) sample of the WIde-field Nearby Galaxy-cluster Survey (WINGS) and other literature results shows that the slope and intrinsic scatter of the cluster red sequence have undergone little evolution since z = 1.5. We find that the luminous-to-faint ratio and the slope of the faint end of the luminosity distribution of the HCS red sequence are consistent with those measured in WINGS, implying that there is no deficit of red galaxies at magnitudes fainter than M_V^{ast } at high redshifts. We find that the most massive HCS clusters host a population of bright red sequence galaxies at MV < -22.0 mag, which are not observed in low-mass clusters. Interestingly, we also note the presence of a population of very bright (MV < -23.0 mag) and massive (log (M*/M⊙) > 11.5) red sequence galaxies in the WINGS clusters, which do not include only the brightest cluster galaxies and which are not present in the HCS clusters, suggesting that they formed at epochs later than z = 0.8. The comparison with the luminosity distribution of a sample of passive red sequence galaxies drawn from the COSMOS/UltraVISTA field in the photometric redshift range 0.8 < zphot < 1.5 shows that the red sequence in clusters is more developed at the faint end, suggesting that halo mass plays an important role in setting the time-scales for the build-up of the red sequence.

  10. Abundance ratios of red giants in low-mass ultra-faint dwarf spheroidal galaxies

    NASA Astrophysics Data System (ADS)

    François, P.; Monaco, L.; Bonifacio, P.; Moni Bidin, C.; Geisler, D.; Sbordone, L.

    2016-04-01

    Context. Low-mass dwarf spheroidal galaxies are key objects for our understanding of the chemical evolution of the pristine Universe and the Local Group of galaxies. Abundance ratios in stars of these objects can be used to better understand their star formation and chemical evolution. Aims: We report on the analysis of a sample of 11 stars belonging to five different ultra-faint dwarf spheroidal galaxies (UfDSph) that is based on X-Shooter spectra obtained at the VLT. Methods: Medium-resolution spectra have been used to determine the detailed chemical composition of their atmosphere. We performed a standard 1D LTE analysis to compute the abundances. Results: Considering all the stars as representative of the same population of low-mass galaxies, we found that the [α/Fe] ratios vs.s [Fe/H] decreases as the metallicity of the star increases in a way similar to that which is found for the population of stars that belong to dwarf spheroidal galaxies. The main difference is that the solar [α/Fe] is reached at a much lower metallicity for the UfDSph than for the dwarf spheroidal galaxies. We report for the first time the abundance of strontium in CVn II. The star we analyzed in this galaxy has a very high [Sr/Fe] and a very low upper limit of barium which makes it a star with an exceptionally high [Sr/Ba] ratio.

  11. The built-up of the red sequence in the Hercules cluster

    NASA Astrophysics Data System (ADS)

    Agulli, I.; Aguerri, J. A. L.; Dominguez Palmero, L.; Diaferio, A.

    2016-09-01

    We present the study of the colour-magnitude diagram of the cluster Abell 2151 (A 2151), with a particular focus on the low-mass end. The deep spectroscopy with AF2/WYFFOS@WHT and the caustic method enable us to obtain 360 members within 1.3 R200 and absolute magnitude M_r ≲ M_r^{ast }+6. This nearby cluster shows a well defined red sequence up to Mr ˜ -18.5; at fainter magnitudes only 36 per cent of the galaxies lie on the extrapolation of the red sequence. We compare the red sequences of A 2151 and Abell 85, which is another nearby cluster with similar spectroscopic data, but with different mass and dynamical state. Both clusters show similar red sequences at the bright end (Mr ≤ -19.5), whereas large differences appear at the faint end. This result suggests that the reddening of bright galaxies is independent of environment, unlike the dwarf population (Mr ≥ -18.0).

  12. A TALE OF DWARFS AND GIANTS: USING A z = 1.62 CLUSTER TO UNDERSTAND HOW THE RED SEQUENCE GREW OVER THE LAST 9.5 BILLION YEARS

    SciTech Connect

    Rudnick, Gregory H.; Tran, Kim-Vy; Papovich, Casey; Momcheva, Ivelina; Willmer, Christopher

    2012-08-10

    We study the red sequence in a cluster of galaxies at z = 1.62 and follow its evolution over the intervening 9.5 Gyr to the present day. Using deep YJK{sub s} imaging with the HAWK-I instrument on the Very Large Telescope, we identify a tight red sequence and construct its rest-frame i-band luminosity function (LF). There is a marked deficit of faint red galaxies in the cluster that causes a turnover in the LF. We compare the red-sequence LF to that for clusters at z < 0.8, correcting the luminosities for passive evolution. The shape of the cluster red-sequence LF does not evolve between z = 1.62 and z = 0.6 but at z < 0.6 the faint population builds up significantly. Meanwhile, between z = 1.62 and 0.6 the inferred total light on the red sequence grows by a factor of {approx}2 and the bright end of the LF becomes more populated. We construct a simple model for red-sequence evolution that grows the red sequence in total luminosity and matches the constant LF shape at z > 0.6. In this model the cluster accretes blue galaxies from the field whose star formation is quenched and who are subsequently allowed to merge. We find that three to four mergers among cluster galaxies during the 4 Gyr between z = 1.62 and z = 0.6 match the observed LF evolution between the two redshifts. The inferred merger rate is consistent with other studies of this cluster. Our result supports the picture that galaxy merging during the major growth phase of massive clusters is an important process in shaping the red-sequence population at all luminosities.

  13. Fainting (Syncope)

    MedlinePlus

    ... Adults Making Your Wishes Known Home & Community Home › Aging & Health A to Z › Fainting (Syncope) Font size A A A Print Share Glossary Basic Facts & Information Causes & Symptoms Diagnosis & Tests Care & Treatment Lifestyle & Management Other Resources Caregiving How ...

  14. Measuring the Red Sequence Slope in a Distant Galaxy Cluster

    NASA Astrophysics Data System (ADS)

    Schultz, Erin; Rudnick, G.

    2013-01-01

    Our project goal is to constrain the possible stellar mass dependence of galaxy ages for red sequence galaxies. We use the Y, J, and K-band data collected from the Very Large Telescope in Chile of the z = 1.62 galaxy cluster XMM-LSS J02182-051020. This spectroscopically confirmed galaxy cluster is one of the only known massive clusters at an epoch close to the time when stars stopped forming within red sequence galaxies. For red sequence galaxies, which have little recent star formation and little dust, the color is an indicator of the luminosity weighted age of the stars. This is in turn correlated to the last epoch of significant star formation. At the same time, the mass of such a galaxy is correlated to its magnitude. The more stars a galaxy contains, the more massive and brighter the galaxy. The slope of the red sequence in color-magnitude space, therefore, gives an indication of the dependence of galaxy age on stellar mass. We use the age-sensitive Y-J color and measure a slope of zero for the red sequence in Y-J vs. J. We interpret this to mean that the age does not depend strongly on the mass of the galaxy. We will present the limits on the slope of the color-magnitude relation and will discuss what limits this corresponds to on the age dependence with mass.

  15. MODELING THE RED SEQUENCE: HIERARCHICAL GROWTH YET SLOW LUMINOSITY EVOLUTION

    SciTech Connect

    Skelton, Rosalind E.; Bell, Eric F.; Somerville, Rachel S.

    2012-07-01

    We explore the effects of mergers on the evolution of massive early-type galaxies by modeling the evolution of their stellar populations in a hierarchical context. We investigate how a realistic red sequence population set up by z {approx} 1 evolves under different assumptions for the merger and star formation histories, comparing changes in color, luminosity, and mass. The purely passive fading of existing red sequence galaxies, with no further mergers or star formation, results in dramatic changes at the bright end of the luminosity function and color-magnitude relation. Without mergers there is too much evolution in luminosity at a fixed space density compared to observations. The change in color and magnitude at a fixed mass resembles that of a passively evolving population that formed relatively recently, at z {approx} 2. Mergers among the red sequence population ('dry mergers') occurring after z = 1 build up mass, counteracting the fading of the existing stellar populations to give smaller changes in both color and luminosity for massive galaxies. By allowing some galaxies to migrate from the blue cloud onto the red sequence after z = 1 through gas-rich mergers, younger stellar populations are added to the red sequence. This manifestation of the progenitor bias increases the scatter in age and results in even smaller changes in color and luminosity between z = 1 and z = 0 at a fixed mass. The resultant evolution appears much slower, resembling the passive evolution of a population that formed at high redshift (z {approx} 3-5), and is in closer agreement with observations. We conclude that measurements of the luminosity and color evolution alone are not sufficient to distinguish between the purely passive evolution of an old population and cosmologically motivated hierarchical growth, although these scenarios have very different implications for the mass growth of early-type galaxies over the last half of cosmic history.

  16. OBSERVATIONAL CONSTRAINTS ON RED AND BLUE HELIUM BURNING SEQUENCES

    SciTech Connect

    McQuinn, Kristen B. W.; Skillman, Evan D.; Dalcanton, Julianne J.; Weisz, Daniel R.; Williams, Benjamin F.; Dolphin, Andrew E.; Holtzman, Jon

    2011-10-10

    We derive the optical luminosity, colors, and ratios of the blue and red helium burning (HeB) stellar populations from archival Hubble Space Telescope observations of nineteen starburst dwarf galaxies and compare them with theoretical isochrones from Padova stellar evolution models across metallicities from Z = 0.001 to 0.009. We find that the observational data and the theoretical isochrones for both blue and red HeB populations overlap in optical luminosities and colors and the observed and predicted blue to red HeB ratios agree for stars older than 50 Myr over the time bins studied. These findings confirm the usefulness of applying isochrones to interpret observations of HeB populations. However, there are significant differences, especially for the red HeB population. Specifically, we find (1) offsets in color between the observations and theoretical isochrones of order 0.15 mag (0.5 mag) for the blue (red) HeB populations brighter than M{sub V} {approx} -4 mag, which cannot be solely due to differential extinction; (2) blue HeB stars fainter than M{sub V} {approx} -3 mag are bluer than predicted; (3) the slope of the red HeB sequence is shallower than predicted by a factor of {approx}3; and (4) the models overpredict the ratio of the most luminous blue to red HeB stars corresponding to ages {approx}< 50 Myr. Additionally, we find that for the more metal-rich galaxies in our sample (Z {approx}> 0.5 Z{sub sun}), the red HeB stars overlap with the red giant branch stars in the color-magnitude diagrams, thus reducing their usefulness as indicators of star formation for ages {approx}> 100 Myr.

  17. THE FAINT STELLAR HALOS OF MASSIVE RED GALAXIES FROM STACKS OF MORE THAN 42,000 SDSS LRG IMAGES

    SciTech Connect

    Tal, Tomer; Van Dokkum, Pieter G.

    2011-04-20

    We study the properties of massive galaxies at an average redshift of z {approx} 0.34 through stacking more than 42,000 images of luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS). This is the largest data set ever used for such an analysis and it allows us to explore the outskirts of massive red galaxies at unprecedented physical scales. Our image stacks extend farther than 400 kpc, where the r-band profile surface brightness reaches 30 mag arcsec{sup -2}. This analysis confirms that the stellar bodies of LRGs follow a simple Sersic profile out to 100 kpc. At larger radii, the profiles deviate from the best-fit Sersic models and exhibit extra light in the r-, i-, and z-band stacks. This excess light can probably be attributed to unresolved intragroup or intracluster light or a change in the light profile itself. We further show that standard analyses of SDSS-depth images typically miss 20% of the total stellar light and underestimate the size of LRGs by 10% compared to our best-fit r-band Sersic model of n = 5.5 and r{sub e} = 13.1 kpc. If the excess light at r > 100 kpc is considered to be part of the galaxy, the best-fit r-band Sersic parameters are n = 5.8 and r{sub e} = 13.6 kpc. In addition, we study the radially dependent stack ellipticity and find an increase with radius from {epsilon} = 0.25 at r = 10 kpc to {epsilon} = 0.3 at r = 100 kpc. This provides support that the stellar light that we trace out to at least 100 kpc is physically associated with the galaxies themselves and may confirm that the halos of individual LRGs have higher ellipticities than their central parts. Lastly, we show that the broadband color gradients of the stacked images are flat beyond roughly 40 kpc, suggesting that the stellar populations do not vary significantly with radius in the outer parts of massive ellipticals.

  18. PRIMUS: Obscured Star Formation on the Red Sequence

    NASA Astrophysics Data System (ADS)

    Zhu, Guangtun; Blanton, Michael R.; Burles, Scott M.; Coil, Alison L.; Cool, Richard J.; Eisenstein, Daniel J.; Moustakas, John; Wong, Kenneth C.; Aird, James

    2011-01-01

    We quantify the fraction of galaxies at moderate redshifts (0.1 < z < 0.5) that appear red-and-dead in the optical, but in fact contain obscured star formation detectable in the infrared (IR), with the PRIsm MUlti-object Survey (PRIMUS). PRIMUS has measured ~120,000 robust redshifts with a precision of σ z /(1 + z) ~ 0.5% over 9.1 deg2 of the sky to the depth of i ~ 23 (AB), up to redshift z ~ 1. We specifically targeted 6.7 deg2 fields with existing deep IR imaging from the Spitzer Space Telescope from the SWIRE and S-COSMOS surveys. We select in these fields an i-band flux-limited sample (i < 20 mag in the SWIRE fields and i < 21 mag in the S-COSMOS field) of 3310 red-sequence galaxies at 0.1 < z < 0.5 for which we can reliably classify obscured star-forming (SF) and quiescent galaxies using IR color. Our sample constitutes the largest galaxy sample at intermediate redshift to study obscured star formation on the red sequence, and we present the first quantitative analysis of the fraction of obscured SF galaxies as a function of luminosity. We find that on average, at L ~ L*, about 15% of red-sequence galaxies have IR colors consistent with SF galaxies. The percentage of obscured SF galaxies increases by ~8% per mag with decreasing luminosity from the highest luminosities to L ~ 0.2 L*. Our results suggest that a significant fraction of red-sequence galaxies have ongoing star formation and that galaxy evolution studies based on optical color therefore need to account for this complication.

  19. PRIMUS: OBSCURED STAR FORMATION ON THE RED SEQUENCE

    SciTech Connect

    Zhu Guangtun; Blanton, Michael R.; Burles, Scott M.; Coil, Alison L.; Moustakas, John; Aird, James; Cool, Richard J.; Eisenstein, Daniel J.; Wong, Kenneth C.

    2011-01-10

    We quantify the fraction of galaxies at moderate redshifts (0.1 < z < 0.5) that appear red-and-dead in the optical, but in fact contain obscured star formation detectable in the infrared (IR), with the PRIsm MUlti-object Survey (PRIMUS). PRIMUS has measured {approx}120,000 robust redshifts with a precision of {sigma}{sub z}/(1 + z) {approx} 0.5% over 9.1 deg{sup 2} of the sky to the depth of i {approx} 23 (AB), up to redshift z {approx} 1. We specifically targeted 6.7 deg{sup 2} fields with existing deep IR imaging from the Spitzer Space Telescope from the SWIRE and S-COSMOS surveys. We select in these fields an i-band flux-limited sample (i < 20 mag in the SWIRE fields and i < 21 mag in the S-COSMOS field) of 3310 red-sequence galaxies at 0.1 < z < 0.5 for which we can reliably classify obscured star-forming (SF) and quiescent galaxies using IR color. Our sample constitutes the largest galaxy sample at intermediate redshift to study obscured star formation on the red sequence, and we present the first quantitative analysis of the fraction of obscured SF galaxies as a function of luminosity. We find that on average, at L {approx} L*, about 15% of red-sequence galaxies have IR colors consistent with SF galaxies. The percentage of obscured SF galaxies increases by {approx}8% per mag with decreasing luminosity from the highest luminosities to L {approx} 0.2 L*. Our results suggest that a significant fraction of red-sequence galaxies have ongoing star formation and that galaxy evolution studies based on optical color therefore need to account for this complication.

  20. RCSLenS: The Red Cluster Sequence Lensing Survey

    NASA Astrophysics Data System (ADS)

    Hildebrandt, H.; Choi, A.; Heymans, C.; Blake, C.; Erben, T.; Miller, L.; Nakajima, R.; van Waerbeke, L.; Viola, M.; Buddendiek, A.; Harnois-Déraps, J.; Hojjati, A.; Joachimi, B.; Joudaki, S.; Kitching, T. D.; Wolf, C.; Gwyn, S.; Johnson, N.; Kuijken, K.; Sheikhbahaee, Z.; Tudorica, A.; Yee, H. K. C.

    2016-08-01

    We present the Red-sequence Cluster Lensing Survey (RCSLenS), an application of the methods developed for the Canada France Hawaii Telescope Lensing Survey (CFHTLenS) to the ˜785 deg2, multi-band imaging data of the Red-sequence Cluster Survey 2 (RCS2). This project represents the largest public, sub-arcsecond seeing, multi-band survey to date that is suited for weak gravitational lensing measurements. With a careful assessment of systematic errors in shape measurements and photometric redshifts we extend the use of this data set to allow cross-correlation analyses between weak lensing observables and other data sets. We describe the imaging data, the data reduction, masking, multi-colour photometry, photometric redshifts, shape measurements, tests for systematic errors, and a blinding scheme to allow for more objective measurements. In total we analyse 761 pointings with r-band coverage, which constitutes our lensing sample. Residual large-scale B-mode systematics prevent the use of this shear catalogue for cosmic shear science. The effective number density of lensing sources over an unmasked area of 571.7 deg2 and down to a magnitude limit of r ˜ 24.5 is 8.1 galaxies per arcmin2 (weighted: 5.5 arcmin-2) distributed over 14 patches on the sky. Photometric redshifts based on 4-band griz data are available for 513 pointings covering an unmasked area of 383.5 deg2. We present weak lensing mass reconstructions of some example clusters as well as the full survey representing the largest areas that have been mapped in this way. All our data products are publicly available through CADC at http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/community/rcslens/query.html in a format very similar to the CFHTLenS data release.

  1. Red Dwarfs and the End of the Main Sequence

    NASA Astrophysics Data System (ADS)

    Adams, F. C.; Graves, G. J. M.; Laughlin, G.

    2004-12-01

    This paper celebrates the contributions of Peter Bodenheimer to our understanding of stellar evolution by focusing on the long term development of red dwarf stars. We show that these diminutive stellar objects remain convective over most of their lives, they continue to burn hydrogen for trillions of years, and they do not experience red giant phases in their old age. Instead, red dwarfs turn into blue dwarfs and finally white dwarfs. This work shows (in part) why larger stars do become red giants.

  2. Precision Measurements of the Cluster Red Sequence using an Error Corrected Gaussian Mixture Model

    SciTech Connect

    Hao, Jiangang; Koester, Benjamin P.; Mckay, Timothy A.; Rykoff, Eli S.; Rozo, Eduardo; Evrard, August; Annis, James; Becker, Matthew; Busha, Michael; Gerdes, David; Johnston, David E.; /Northwestern U. /Brookhaven

    2009-07-01

    The red sequence is an important feature of galaxy clusters and plays a crucial role in optical cluster detection. Measurement of the slope and scatter of the red sequence are affected both by selection of red sequence galaxies and measurement errors. In this paper, we describe a new error corrected Gaussian Mixture Model for red sequence galaxy identification. Using this technique, we can remove the effects of measurement error and extract unbiased information about the intrinsic properties of the red sequence. We use this method to select red sequence galaxies in each of the 13,823 clusters in the maxBCG catalog, and measure the red sequence ridgeline location and scatter of each. These measurements provide precise constraints on the variation of the average red galaxy populations in the observed frame with redshift. We find that the scatter of the red sequence ridgeline increases mildly with redshift, and that the slope decreases with redshift. We also observe that the slope does not strongly depend on cluster richness. Using similar methods, we show that this behavior is mirrored in a spectroscopic sample of field galaxies, further emphasizing that ridgeline properties are independent of environment. These precise measurements serve as an important observational check on simulations and mock galaxy catalogs. The observed trends in the slope and scatter of the red sequence ridgeline with redshift are clues to possible intrinsic evolution of the cluster red-sequence itself. Most importantly, the methods presented in this work lay the groundwork for further improvements in optically-based cluster cosmology.

  3. WHAT DOES CLUSTERING TELL US ABOUT THE BUILDUP OF THE RED SEQUENCE?

    SciTech Connect

    Tinker, Jeremy L.; Wetzel, Andrew R.

    2010-08-10

    We analyze the clustering of red and blue galaxies from four samples spanning a redshift range of 0.4 < z < 2.0 to test the various scenarios by which galaxies evolve onto the red sequence. The data are taken from the UKIDSS Ultra Deep Survey, DEEP2, and COMBO-17. The use of clustering allows us to determine what fraction of the red sequence is made up of central galaxies and satellite galaxies. At all redshifts, including z = 0, the data are consistent with {approx}60% of satellite galaxies being red or quenched, implying that {approx}1/3 of the red sequence is comprised of satellite galaxies. More than three-fourths of red satellite galaxies were moved to the red sequence after they were accreted onto a larger halo. The constant fraction of satellite galaxies that are red yields a quenching time for satellite galaxies that depends on redshift in the same way as halo dynamical times: t{sub Q} {approx} (1 + z){sup -1.5}. In three of the four samples, the data favor a model in which red central galaxies are a random sample of all central galaxies; there is no preferred halo mass scale at which galaxies make the transition from star-forming to red and dead. The large errors on the fourth sample inhibit any conclusions. Theoretical models in which star formation is quenched above a critical halo mass are excluded by these data. A scenario in which mergers create red central galaxies imparts a weaker correlation between halo mass and central galaxy color, but even the merger scenario creates tension with red galaxy clustering at redshifts above 0.5. These results suggest that the mechanism by which central galaxies become red evolves from z = 0.5 to z = 0.

  4. Can the magnetic susceptibility record of Chinese Red Clay sequence be used for palaeomonsoon reconstructions?

    NASA Astrophysics Data System (ADS)

    Zhao, Guoyong; Han, Yan; Liu, Xiuming; Chang, Liao; Lü, Bin; Chen, Qu; Guo, Xuelian; Yan, Junhui; Yan, Jun

    2016-03-01

    Red Clay underlying the loess-palaeosol sequences on the Chinese Loess Plateau is an eolian deposit. There is a controversy over whether magnetic susceptibility (χ) variations in Red Clay sequence can be used as an indicator of summer palaeomonsoon intensity. This study investigates the magnetic mineralogy, magnetic concentration and magnetic grain size distribution of Jiaxian Red Clay with multimagnetic methods. Our results indicate that the magnetic properties of Jiaxian Red Clay are similar to those of the Quaternary loess-palaeosol sequences, and ultrafine ferrimagnetic grains produced during pedogenesis are responsible for an increase in susceptibility, therefore the χ enhancement mechanism of Red Clay is similar to that of the overlying loess-palaeosol sequences. This paper explores χ variations in the Red Clay sequence through spatial and temporal analysis. The susceptibility variation of six sites along a NNE to SSW transect correlate to palaeoclimatic cycles, so χ can be used to trace the summer palaeomonsoon intensity from a spatial perspective. However, a simple loess-derived calibration function cannot be used to quantitative reconstruct the palaeomonsoon intensity variations thought time. An adjusted calibration function for palaeosols from Red Clay sequence needs to be developed, so that χ can be used to quantitative reconstruct palaeomonsoon intensity. Further study is necessary to develop such a transfer function.

  5. Cosmological Constraints from the Red-Sequence Cluster Survey

    NASA Astrophysics Data System (ADS)

    Gladders, Michael D.; Yee, H. K. C.; Majumdar, Subhabrata; Barrientos, L. Felipe; Hoekstra, Henk; Hall, Patrick B.; Infante, Leopoldo

    2007-01-01

    We present a first cosmological analysis of a refined cluster catalog from the Red-Sequence Cluster Survey (RCS). The input cluster sample is derived from the deepest 72.07 deg2 of the RCS images, which probe to the highest redshift and lowest mass limits. The catalog contains 956 clusters over 0.35

  6. THE WiggleZ DARK ENERGY SURVEY: GALAXY EVOLUTION AT 0.25 {<=} z {<=} 0.75 USING THE SECOND RED-SEQUENCE CLUSTER SURVEY

    SciTech Connect

    Li, I. H.; Blake, Chris; Contreras, Carlos; Couch, Warrick J.; Glazebrook, Karl; Yee, H. K. C.; Brough, Sarah; Colless, Matthew; Croom, Scott M.; Jelliffe, Ben; Davis, Tamara; Drinkwater, Michael J.; Forster, Karl; Martin, D. Christopher; Gilbank, David G.; Gladders, M. G.; Hsieh, Bau-ching; Jurek, Russell J.; Madore, Barry; Pimbblet, Kevin; and others

    2012-03-10

    We study the evolution of galaxy populations around the spectroscopic WiggleZ sample of star-forming galaxies at 0.25 {<=} z {<=} 0.75 using the photometric catalog from the Second Red-Sequence Cluster Survey (RCS2). We probe the optical photometric properties of the net excess neighbor galaxies. The key concept is that the marker galaxies and their neighbors are located at the same redshift, providing a sample of galaxies representing a complete census of galaxies in the neighborhood of star-forming galaxies. The results are compared with those using the RCS WiggleZ Spare-Fibre (RCS-WSF) sample as markers, representing galaxies in cluster environments at 0.25 {<=} z {<=} 0.45. By analyzing the stacked color-color properties of the WiggleZ neighbor galaxies, we find that their optical colors are not a strong function of indicators of star-forming activities such as EW([O II]) or Galaxy Evolution Explorer (GALEX) near-UV luminosity of the markers. The galaxies around the WiggleZ markers exhibit a bimodal distribution on the color-magnitude diagram, with most of them located in the blue cloud. The optical galaxy luminosity functions (GLFs) of the blue neighbor galaxies have a faint-end slope {alpha} of {approx} - 1.3, similar to that for galaxies in cluster environments drawn from the RCS-WSF sample. The faint-end slope of the GLF for the red neighbors, however, is {approx} - 0.4, significantly shallower than the {approx} - 0.7 found for those in cluster environments. This suggests that the buildup of the faint end of the red sequence in cluster environments is in a significantly more advanced stage than that in the star-forming and lower galaxy density WiggleZ neighborhoods. We find that the red galaxy fraction (f{sub red}) around the star-forming WiggleZ galaxies has similar values from z {approx} 0.3 to z {approx} 0.6 with f{sub red} {approx} 0.28, but drops to f{sub red} {approx} 0.20 at z {approx}> 0.7. This change of f{sub red} with redshift suggests that there

  7. Fainting Starting Parenteral Nutrition.

    PubMed

    Pederiva, Federica; Barbi, Egidio; Zennaro, Floriana; Neri, Elena

    2015-09-01

    Complications such as mechanical accidents, infections, and thrombosis are commonly described in the presence of a central venous catheter. We present a case of a boy who had fainting episodes due to dislocation of a central venous catheter. PMID:25853719

  8. Galaxy Zoo Hubble: First results of the redshift evolution of disk fraction in the red sequence

    NASA Astrophysics Data System (ADS)

    Galloway, Melanie; Willett, Kyle; Fortson, Lucy; Scarlata, Claudia; Beck, Melanie; Masters, Karen; Melvin, Tom

    2016-01-01

    The transition of galaxies from the blue cloud to the red sequence is commonly linked to a morphological transformation from disk to elliptical structure. However, the correlation between color and morphology is not one-to-one, as evidenced by the existence of a significant population of red disks. As this stage in a galaxy's evolution is likely to be transitory, the mechanism by which red disks are formed offers insight to the processes that trigger quenching of star formation and the galaxy's position on the star-forming sequence. To study the population of disk galaxies in the red sequence as a function of cosmic time, we utilize data from the Galaxy Zoo: Hubble project, which uses crowdsourced visual classifications of images of galaxies selected from the AEGIS, COSMOS, GEMS, and GOODS surveys. We construct a large sample of over 10,000 disk galaxies spanning a wide (0 < z < 1.0) redshift range. We use this sample to examine the change in the fraction of disks in the red sequence with respect to all disks from z˜1 to the present day. Preliminary results confirm that the fraction of disks in the red sequence decreases as the Universe evolves. We discuss the quenching processes which may explain this trend, and which morphological transformations are most affected by it.

  9. Evolution of Group Galaxies from the First Red-Sequence Cluster Survey

    NASA Astrophysics Data System (ADS)

    Li, I. H.; Yee, H. K. C.; Hsieh, B. C.; Gladders, M.

    2012-04-01

    We study the evolution of the red-galaxy fraction (f red) in 905 galaxy groups with 0.15 <= z < 0.52. The galaxy groups are identified by the "probability friends-of-friends" algorithm from the first Red-Sequence Cluster Survey (RCS1) photometric-redshift sample. There is a high degree of uniformity in the properties of the red sequence of the group galaxies, indicating that the luminous red-sequence galaxies in the groups are already in place by z ~ 0.5 and that they have a formation epoch of z >~ 2. In general, groups at lower redshifts exhibit larger f red than those at higher redshifts, showing a group Butcher-Oemler effect. We investigate the evolution of f red by examining its dependence on four parameters, one of which can be classified as intrinsic and three of which can be classified as environmental: galaxy stellar mass (M *), total group stellar mass (M *, grp, a proxy for group halo mass), normalized group-centric radius (r grp), and local galaxy density (Σ5). We find that M * is the dominant parameter such that there is a strong correlation between f red and galaxy stellar mass. Furthermore, the dependence of f red on the environmental parameters is also a strong function of M *. Massive galaxies (M * >~ 1011 M ⊙) show little dependence of f red on r grp, M *, grp, and Σ5 over the redshift range. The dependence of f red on these parameters is primarily seen for galaxies with lower masses, especially for M * <~ 1010.6 M ⊙. We observe an apparent "group down-sizing" effect, in that galaxies in lower-mass halos, after controlling for galaxy stellar mass, have lower f red. We find a dependence of f red on both r grp and Σ5 after the other parameters are controlled. At a fixed r grp, there is a significant dependence of f red on Σ5, while r grp gradients of f red are seen for galaxies in similar Σ5 regions. This indicates that galaxy group environment has a residual effect over that of local galaxy density (or vice versa), and both parameters need

  10. Probing the Deep End of the Milky Way with Kepler: Asteroseismic Analysis of 854 Faint Red Giants Misclassified as Cool Dwarfs

    NASA Astrophysics Data System (ADS)

    Mathur, S.; García, R. A.; Huber, D.; Regulo, C.; Stello, D.; Beck, P. G.; Houmani, K.; Salabert, D.

    2016-08-01

    Asteroseismology has proven to be an excellent tool to determine not only global stellar properties with good precision, but also to infer the stellar structure, dynamics, and evolution for a large sample of Kepler stars. Prior to the launch of the mission, the properties of Kepler targets were inferred from broadband photometry, leading to the Kepler Input Catalog (KIC). The KIC was later revised in the Kepler Star Properties Catalog, based on literature values and an asteroseismic analysis of stars that were unclassified in the KIC. Here, we present an asteroseismic analysis of 45,400 stars that were classified as dwarfs in the Kepler Star Properties Catalog. We found that around 2% of the sample shows acoustic modes in the typical frequency range that put them in the red-giant category rather than the cool dwarf category. We analyze the asteroseismic properties of these stars, derive their surface gravities, masses, and radii, and present updated effective temperatures and distances. We show that the sample is significantly fainter than the previously known oscillating giants in the Kepler field, with the faintest stars reaching down to a Kepler magnitude of Kp ˜ 16. We demonstrate that 404 stars are at distances beyond 5 kpc and that the stars are significantly less massive than for the original Kepler red-giant sample, consistent with a population of distant halo giants. A comparison with a galactic population model shows that up to 40 stars might be genuine halo giants, which would increase the number of known asteroseismic halo stars by a factor of 4. The detections presented here will provide a valuable sample for galactic archeology studies.

  11. Evidence for the Universality of Properties of Red-sequence Galaxies in X-Ray- and Red-Sequence-Selected Clusters at z ~ 1

    NASA Astrophysics Data System (ADS)

    Foltz, R.; Rettura, A.; Wilson, G.; van der Burg, R. F. J.; Muzzin, A.; Lidman, C.; Demarco, R.; Nantais, Julie; DeGroot, A.; Yee, H.

    2015-10-01

    We study the slope, intercept, and scatter of the color-magnitude and color-mass relations for a sample of 10 infrared red-sequence-selected clusters at z ˜ 1. The quiescent galaxies in these clusters formed the bulk of their stars above z ≳ 3 with an age spread Δt ≳ 1 Gyr. We compare UVJ color-color and spectroscopic-based galaxy selection techniques, and find a 15% difference in the galaxy populations classified as quiescent by these methods. We compare the color-magnitude relations from our red-sequence selected sample with X-ray- and photometric-redshift-selected cluster samples of similar mass and redshift. Within uncertainties, we are unable to detect any difference in the ages and star formation histories of quiescent cluster members in clusters selected by different methods, suggesting that the dominant quenching mechanism is insensitive to cluster baryon partitioning at z ˜ 1.

  12. Cyclostratigraphy for Chinese red clay sequences: Implications to changing previous age models and paleoclimate interpretations

    NASA Astrophysics Data System (ADS)

    Anwar, T.; Kravchinsky, V. A.; Zhang, R.

    2015-12-01

    The Chinese Loess Plateau contains red clay sequence which has continuous alternation of sedimentary cycles with recurrent paleoclimatic fluctuations. Absence of abundant fossils and inability of radiometric dating method made magnetostratigraphy a leading method to build age model for the red clay. Here magnetostratigraphic age model in red clay sequence is tested using cyclostratigraphy as orbital parameters of Earth are known. Milankovitch periodicities recorded in magnetic susceptibility and grain size in the Shilou red clay section are investigated and previously found age of 11 Ma for this section is re-evaluated. Magnetostratigraphy dating based on only visual correlation could potentially lead to erroneous age model. In this study the correlation is executed through the iteration procedure until it is supported by cyclostratigraphy; i.e. Milankovitch cycles are resolved in the best possible manner. Our new approach provides an age of 5.2 Ma for the Shilou profile. Wavelet analysis reveals that a 400 kyr eccentricity cycle is well preserved and the existence of a 100 kyr eccentricity in the red clay sequence on the eastern Chinese Loess Plateau suggests that eccentricity plays a vital role in Pliocene climate evolution. Paleomonsoon evolution is reconstructed and divided into three intervals (5.2-4.5 Ma, 4.5-3.6 Ma and 3.6-2.58 Ma). The earliest stage indicates that summer and winter monsoon cycles may rapidly alter, whereas the middle stage reflects an intensification of winter monsoon and aridification in Asia, and the youngest stage is characterized by relatively intensified summer monsoon. This study demonstrates that cyclostratigraphy can greatly assist magnetostratigraphy in dating the red clay sequences, and implies that many published age models for the red clay sequences should likely be re-assessed where possible. An evaluation of the monsoon system and climate change in eastern Asia might prominently benefit from this approach.

  13. The complete mitochondrial genome sequence of the Tibetan red fox (Vulpes vulpes montana).

    PubMed

    Zhang, Jin; Zhang, Honghai; Zhao, Chao; Chen, Lei; Sha, Weilai; Liu, Guangshuai

    2015-01-01

    In this study, the complete mitochondrial genome of the Tibetan red fox (Vulpes Vulpes montana) was sequenced for the first time using blood samples obtained from a wild female red fox captured from Lhasa in Tibet, China. Qinghai--Tibet Plateau is the highest plateau in the world with an average elevation above 3500 m. Sequence analysis showed it contains 12S rRNA gene, 16S rRNA gene, 22 tRNA genes, 13 protein-coding genes and 1 control region (CR). The variable tandem repeats in CR is the main reason of the length variability of mitochondrial genome among canide animals. PMID:24456141

  14. Sequence divergence of the red and green visual pigments in great apes and humans.

    PubMed Central

    Deeb, S S; Jorgensen, A L; Battisti, L; Iwasaki, L; Motulsky, A G

    1994-01-01

    We have determined the coding sequences of red and green visual pigment genes of the chimpanzee, gorilla, and orangutan. The deduced amino acid sequences of these pigments are highly homologous to the equivalent human pigments. None of the amino acid differences occurred at sites that were previously shown to influence pigment absorption characteristics. Therefore, we predict the spectra of red and green pigments of the apes to have wavelengths of maximum absorption that differ by < 2 nm from the equivalent human pigments and that color vision in these nonhuman primates will be very similar, if not identical, to that in humans. A total of 14 within-species polymorphisms (6 involving silent substitutions) were observed in the coding sequences of the red and green pigment genes of the great apes. Remarkably, the polymorphisms at 6 of these sites had been observed in human populations, suggesting that they predated the evolution of higher primates. Alleles at polymorphic sites were often shared between the red and green pigment genes. The average synonymous rate of divergence of red from green sequences was approximately 1/10th that estimated for other proteins of higher primates, indicating the involvement of gene conversion in generating these polymorphisms. The high degree of homology and juxtaposition of these two genes on the X chromosome has promoted unequal recombination and/or gene conversion that led to sequence homogenization. However, natural selection operated to maintain the degree of separation in peak absorbance between the red and green pigments that resulted in optimal chromatic discrimination. This represents a unique case of molecular coevolution between two homologous genes that functionally interact at the behavioral level. PMID:8041777

  15. The complete nucleotide sequence and genome organization of Red clover vein mosaic virus (genus Carlavirus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red clover vein mosaic virus (RCVMV) is a serious pathogen of legume crops including pea, chickpea and lentil. The complete nucleotide sequence was generated from an isolate obtained from chickpea in Washington State. The complete genome of RCVMV consists of 8605 nucleotides excluding the poly(A) ...

  16. EVOLUTION OF GROUP GALAXIES FROM THE FIRST RED-SEQUENCE CLUSTER SURVEY

    SciTech Connect

    Li, I. H.; Yee, H. K. C.; Hsieh, B. C.; Gladders, M. E-mail: hyee@astro.utoronto.ca E-mail: gladders@oddjob.uchicago.edu

    2012-04-20

    We study the evolution of the red-galaxy fraction (f{sub red}) in 905 galaxy groups with 0.15 {<=} z < 0.52. The galaxy groups are identified by the 'probability friends-of-friends' algorithm from the first Red-Sequence Cluster Survey (RCS1) photometric-redshift sample. There is a high degree of uniformity in the properties of the red sequence of the group galaxies, indicating that the luminous red-sequence galaxies in the groups are already in place by z {approx} 0.5 and that they have a formation epoch of z {approx}> 2. In general, groups at lower redshifts exhibit larger f{sub red} than those at higher redshifts, showing a group Butcher-Oemler effect. We investigate the evolution of f{sub red} by examining its dependence on four parameters, one of which can be classified as intrinsic and three of which can be classified as environmental: galaxy stellar mass (M{sub *}), total group stellar mass (M{sub *,grp}, a proxy for group halo mass), normalized group-centric radius (r{sub grp}), and local galaxy density ({Sigma}{sub 5}). We find that M{sub *} is the dominant parameter such that there is a strong correlation between f{sub red} and galaxy stellar mass. Furthermore, the dependence of f{sub red} on the environmental parameters is also a strong function of M{sub *}. Massive galaxies (M{sub *} {approx}> 10{sup 11} M{sub Sun }) show little dependence of f{sub red} on r{sub grp}, M{sub *,grp}, and {Sigma}{sub 5} over the redshift range. The dependence of f{sub red} on these parameters is primarily seen for galaxies with lower masses, especially for M{sub *} {approx}< 10{sup 10.6} M{sub Sun }. We observe an apparent 'group down-sizing' effect, in that galaxies in lower-mass halos, after controlling for galaxy stellar mass, have lower f{sub red}. We find a dependence of f{sub red} on both r{sub grp} and {Sigma}{sub 5} after the other parameters are controlled. At a fixed r{sub grp}, there is a significant dependence of f{sub red} on {Sigma}{sub 5}, while r{sub grp

  17. RED-SEQUENCE GALAXIES AT HIGH REDSHIFT BY THE COMBO-17+4 SURVEY

    SciTech Connect

    Nicol, Marie-Helene; Meisenheimer, Klaus; Wolf, Christian; Tapken, Christian E-mail: meise@mpia.de E-mail: ctapken@aip.de

    2011-01-20

    We investigate the evolution of the galaxy population since redshift 2 with a focus on the color bimodality and mass density of the red sequence. We obtain precise and reliable photometric redshifts up to z = 2 by supplementing the optical survey COMBO-17 with observations in four near-infrared bands on 0.2 deg{sup 2} of the COMBO-17 A901-field. Our results are based on an H-band-selected catalog of 10,692 galaxies complete to H = 21fm7. We measure the rest-frame color (U{sub 280}-V) of each galaxy, which across the redshift range of our interest requires no extrapolation and is robust against moderate redshift errors by staying clear of the 4000 A break. We measure the color-magnitude relation of the red sequence as a function of look-back time from the peak in a color-error-weighted histogram, and thus trace the galaxy bimodality out to z {approx_equal} 1.65. The (U{sub 280}-V) of the red sequence is found to evolve almost linearly with look-back time. At high redshift, we find massive galaxies in both the red and the blue population. Red-sequence galaxies with log M{sub *}/M{sub sun}>11 increase in mass density by a factor of {approx}4 from z {approx} 2 to 1 and remain nearly constant at z < 1. However, some galaxies as massive as log M{sub *}/M{sub sun} = 11.5 are already in place at z {approx} 2.

  18. The first symbiont-free genome sequence of marine red alga, Susabi-nori (Pyropia yezoensis).

    PubMed

    Nakamura, Yoji; Sasaki, Naobumi; Kobayashi, Masahiro; Ojima, Nobuhiko; Yasuike, Motoshige; Shigenobu, Yuya; Satomi, Masataka; Fukuma, Yoshiya; Shiwaku, Koji; Tsujimoto, Atsumi; Kobayashi, Takanori; Nakayama, Ichiro; Ito, Fuminari; Nakajima, Kazuhiro; Sano, Motohiko; Wada, Tokio; Kuhara, Satoru; Inouye, Kiyoshi; Gojobori, Takashi; Ikeo, Kazuho

    2013-01-01

    Nori, a marine red alga, is one of the most profitable mariculture crops in the world. However, the biological properties of this macroalga are poorly understood at the molecular level. In this study, we determined the draft genome sequence of susabi-nori (Pyropia yezoensis) using next-generation sequencing platforms. For sequencing, thalli of P. yezoensis were washed to remove bacteria attached on the cell surface and enzymatically prepared as purified protoplasts. The assembled contig size of the P. yezoensis nuclear genome was approximately 43 megabases (Mb), which is an order of magnitude smaller than the previously estimated genome size. A total of 10,327 gene models were predicted and about 60% of the genes validated lack introns and the other genes have shorter introns compared to large-genome algae, which is consistent with the compact size of the P. yezoensis genome. A sequence homology search showed that 3,611 genes (35%) are functionally unknown and only 2,069 gene groups are in common with those of the unicellular red alga, Cyanidioschyzon merolae. As color trait determinants of red algae, light-harvesting genes involved in the phycobilisome were predicted from the P. yezoensis nuclear genome. In particular, we found a second homolog of phycobilisome-degradation gene, which is usually chloroplast-encoded, possibly providing a novel target for color fading of susabi-nori in aquaculture. These findings shed light on unexplained features of macroalgal genes and genomes, and suggest that the genome of P. yezoensis is a promising model genome of marine red algae. PMID:23536760

  19. Draft Genome Sequence of Uncultured SAR324 Bacterium lautmerah10, Binned from a Red Sea Metagenome

    PubMed Central

    Thompson, Luke R.

    2016-01-01

    A draft genome of SAR324 bacterium lautmerah10 was assembled from a metagenome of a surface water sample from the Red Sea, Saudi Arabia. The genome is more complete and has a higher G+C content than that of previously sequenced SAR324 representatives. Its genomic information shows a versatile metabolism that confers an advantage to SAR324, which is reflected in its distribution throughout different depths of the marine water column. PMID:26868398

  20. Alignment of Red-Sequence Cluster Dwarf Galaxies: From the Frontier Fields to the Local Universe

    NASA Astrophysics Data System (ADS)

    Barkhouse, Wayne Alan; Archer, Haylee; Burgad, Jaford; Foote, Gregory; Rude, Cody; Lopez-Cruz, Omar

    2015-08-01

    Galaxy clusters are the largest virialized structures in the universe. Due to their high density and mass, they are an excellent laboratory for studying the environmental effects on galaxy evolution. Numerical simulations have predicted that tidal torques acting on dwarf galaxies as they fall into the cluster environment will cause the major axis of the galaxies to align with their radial position vector (a line that extends from the cluster center to the galaxy's center). We have undertaken a study to measure the redshift evolution of the alignment of red-sequence cluster dwarf galaxies based on a sample of 57 low-redshift Abell clusters imaged at KPNO using the 0.9-meter telescope, and 64 clusters from the WINGS dataset. To supplement our low-redshift sample, we have included galaxies selected from the Hubble Space Telescope Frontier fields. Leveraging the HST data allows us to look for evolutionary changes in the alignment of red-sequence cluster dwarf galaxies over a redshift range of 0 < z < 0.35. The alignment of the major axis of the dwarf galaxies is measured by fitting a Sersic function to each red-sequence galaxy using GALFIT. The quality of each model is checked visually after subtracting the model from the galaxy. The cluster sample is then combined by scaling each cluster by r200. We present our preliminary results based on the alignment of the red-sequence dwarf galaxies with: 1) the major axis of the brightest cluster galaxy, 2) the major axis of the cluster defined by the position of cluster members, and 3) a radius vector pointing from the cluster center to individual dwarf galaxies. Our combined cluster sample is sub-divided into different radial regions and redshift bins.

  1. Complete mitochondrial genome sequence of tarim red deer (Cervus elaphus yarkandensis).

    PubMed

    Shao, Yuanchen; Xing, Xiumei; Zha, Daiming; Yang, Fuhe

    2016-01-01

    The complete mitochondrial genome of the tarim red deer, Cervus elaphus yarkandensis, was determined by accurate polymerase chain reaction. The entire genome was 16,351 bp in length and contained 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 1 control region, all of which were arranged in a typical vertebrate manner. The overall base composition of the northeast sika deer's mitochondrial genome was 33.3% of A, 24.4% of C, 28.9% of T and 13.4% of G. A termination-associated sequence and several conserved central sequence block domains were discovered within the control region. PMID:24438284

  2. Unmixing hysteresis loops of the late Miocene–early Pleistocene loess-red clay sequence

    PubMed Central

    Zhang, Rui; Necula, Cristian; Heslop, David; Nie, Junsheng

    2016-01-01

    Magnetic paleoclimatic records often represent mixed environmental signals. Unmixing these signals may improve our understanding of the paleoenvironmental information contained within these records, but such a task is challenging. Here we report an example of numerical unmixing of magnetic hysteresis data obtained from Chinese loess and red clay sequences. We find that the mixed magnetic assemblages of the loess and red clay sediments both contain a component characterized by a narrow hysteresis loop, the abundance of which is positively correlated with magnetic susceptibility. This component has grain sizes close to the superparamagnetic/stable single domain boundary and is attributed to pedogenic activity. Furthermore, a wasp-waisted component is found in both the loess and red clay, however, the wasp-waisted form is more constricted in the red clay. We attribute this component to a mixture of detrital ferrimagnetic grains with pedogenic hematite. The abundance of this component decreases from the base to the top of the red clay, a pattern we attribute to decreased hematite production over the Chinese Loess Plateau (CLP) due to long-term climate cooling. This work demonstrates the potential of hysteresis loop unmixing to recover quantitative paleoclimatic information carried by both low and high coercivity magnetic minerals. PMID:27389499

  3. Unmixing hysteresis loops of the late Miocene-early Pleistocene loess-red clay sequence.

    PubMed

    Zhang, Rui; Necula, Cristian; Heslop, David; Nie, Junsheng

    2016-01-01

    Magnetic paleoclimatic records often represent mixed environmental signals. Unmixing these signals may improve our understanding of the paleoenvironmental information contained within these records, but such a task is challenging. Here we report an example of numerical unmixing of magnetic hysteresis data obtained from Chinese loess and red clay sequences. We find that the mixed magnetic assemblages of the loess and red clay sediments both contain a component characterized by a narrow hysteresis loop, the abundance of which is positively correlated with magnetic susceptibility. This component has grain sizes close to the superparamagnetic/stable single domain boundary and is attributed to pedogenic activity. Furthermore, a wasp-waisted component is found in both the loess and red clay, however, the wasp-waisted form is more constricted in the red clay. We attribute this component to a mixture of detrital ferrimagnetic grains with pedogenic hematite. The abundance of this component decreases from the base to the top of the red clay, a pattern we attribute to decreased hematite production over the Chinese Loess Plateau (CLP) due to long-term climate cooling. This work demonstrates the potential of hysteresis loop unmixing to recover quantitative paleoclimatic information carried by both low and high coercivity magnetic minerals. PMID:27389499

  4. Unmixing hysteresis loops of the late Miocene–early Pleistocene loess-red clay sequence

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Necula, Cristian; Heslop, David; Nie, Junsheng

    2016-07-01

    Magnetic paleoclimatic records often represent mixed environmental signals. Unmixing these signals may improve our understanding of the paleoenvironmental information contained within these records, but such a task is challenging. Here we report an example of numerical unmixing of magnetic hysteresis data obtained from Chinese loess and red clay sequences. We find that the mixed magnetic assemblages of the loess and red clay sediments both contain a component characterized by a narrow hysteresis loop, the abundance of which is positively correlated with magnetic susceptibility. This component has grain sizes close to the superparamagnetic/stable single domain boundary and is attributed to pedogenic activity. Furthermore, a wasp-waisted component is found in both the loess and red clay, however, the wasp-waisted form is more constricted in the red clay. We attribute this component to a mixture of detrital ferrimagnetic grains with pedogenic hematite. The abundance of this component decreases from the base to the top of the red clay, a pattern we attribute to decreased hematite production over the Chinese Loess Plateau (CLP) due to long-term climate cooling. This work demonstrates the potential of hysteresis loop unmixing to recover quantitative paleoclimatic information carried by both low and high coercivity magnetic minerals.

  5. Sequencing and de novo assembly of the red cusk-eel (Genypterus chilensis) transcriptome.

    PubMed

    Aedo, J E; Maldonado, J; Estrada, J M; Fuentes, E N; Silva, H; Gallardo-Escarate, C; Molina, A; Valdés, J A

    2014-12-01

    The red cusk-eel (Genypterus chilensis) is an endemic fish species distributed along the coasts of the Eastern South Pacific. Biological studies on this fish are scarce, and genomic information for G. chilensis is practically non-existent. Thus, transcriptome information for this species is an essential resource that will greatly enrich molecular information and benefit future studies of red cusk-eel biology. In this work, we obtained transcriptome information of G. chilensis using the Illumina platform. The RNA sequencing generated 66,307,362 and 59,925,554 paired-end reads from skeletal muscle and liver tissues, respectively. De novo assembly using the CLC Genomic Workbench version 7.0.3 produced 48,480 contigs and created a reference transcriptome with a N50 of 846bp and average read coverage of 28.3×. By sequence similarity search for known proteins, a total of 21,272 (43.9%) contigs were annotated for their function. Out of these annotated contigs, 33.5% GO annotation results for biological processes, 32.6% GO annotation results for cellular components and 34.5% GO annotation results for molecular functions. This dataset represents the first transcriptomic resource for the red cusk-eel and for a member of the Ophidiimorpharia taxon. PMID:25139027

  6. Recent Galaxy Mergers and Residual Star Formation of Red Sequence Galaxies in Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Sheen, Yun-Kyeong; Yi, Sukyoung K.; Ree, Chang H.; Jaffé, Yara; Demarco, Ricardo; Treister, Ezequiel

    2016-08-01

    This study explored the Galaxy Evolution Explorer ultraviolet (UV) properties of optical red sequence galaxies in four rich Abell clusters at z≤slant 0.1. In particular, we tried to find a hint of merger-induced recent star formation (RSF) in red sequence galaxies. Using the NUV - r\\prime colors of the galaxies, RSF fractions were derived based on various criteria for post-merger galaxies and normal galaxies. Following k-correction, about 36% of the post-merger galaxies were classified as RSF galaxies with a conservative criterion (NUV - r\\prime ≤slant 5), and that number was doubled (∼72%) when using a generous criterion (NUV - r\\prime ≤slant 5.4). The trend was the same when we restricted the sample to galaxies within 0.5 × R 200. Post-merger galaxies with strong UV emission showed more violent, asymmetric features in the deep optical images. The RSF fractions did not show any trend along the clustocentric distance within R 200. We performed a Dressler–Shectman test to check whether the RSF galaxies had any correlation with the substructures in the galaxy clusters. Within R 200 of each cluster, the RSF galaxies did not appear to be preferentially related to the clusters’ substructures. Our results suggested that only 30% of RSF red sequence galaxies show morphological hints of recent galaxy mergers. This implies that internal processes (e.g., stellar mass loss or hot gas cooling) for the supply of cold gas to early-type galaxies may play a significant role in the residual star formation of early-type galaxies at a recent epoch.

  7. Recent Galaxy Mergers and Residual Star Formation of Red Sequence Galaxies in Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Sheen, Yun-Kyeong; Yi, Sukyoung K.; Ree, Chang H.; Jaffé, Yara; Demarco, Ricardo; Treister, Ezequiel

    2016-08-01

    This study explored the Galaxy Evolution Explorer ultraviolet (UV) properties of optical red sequence galaxies in four rich Abell clusters at z≤slant 0.1. In particular, we tried to find a hint of merger-induced recent star formation (RSF) in red sequence galaxies. Using the NUV - r\\prime colors of the galaxies, RSF fractions were derived based on various criteria for post-merger galaxies and normal galaxies. Following k-correction, about 36% of the post-merger galaxies were classified as RSF galaxies with a conservative criterion (NUV - r\\prime ≤slant 5), and that number was doubled (˜72%) when using a generous criterion (NUV - r\\prime ≤slant 5.4). The trend was the same when we restricted the sample to galaxies within 0.5 × R 200. Post-merger galaxies with strong UV emission showed more violent, asymmetric features in the deep optical images. The RSF fractions did not show any trend along the clustocentric distance within R 200. We performed a Dressler–Shectman test to check whether the RSF galaxies had any correlation with the substructures in the galaxy clusters. Within R 200 of each cluster, the RSF galaxies did not appear to be preferentially related to the clusters’ substructures. Our results suggested that only 30% of RSF red sequence galaxies show morphological hints of recent galaxy mergers. This implies that internal processes (e.g., stellar mass loss or hot gas cooling) for the supply of cold gas to early-type galaxies may play a significant role in the residual star formation of early-type galaxies at a recent epoch.

  8. Detection of sequence polymorphisms in red junglefowl and White Leghorn ESTs.

    PubMed

    Fitzsimmons, C J; Savolainen, P; Amini, B; Hjälm, G; Lundeberg, J; Andersson, L

    2004-10-01

    Over 16,000 high quality expressed sequence tags (ESTs) from red junglefowl (RJ) and White Leghorn (WL) brain and testis cDNA libraries were generated. Here, we have used this resource for detection of single nucleotide polymorphisms (SNPs), and also completed full-length sequencing of 46 pairs of clones, representing the same gene from both the RJ and WL libraries. From the main set of ESTs, which were assembled using Phrap, 746 putative SNPs were identified, of which 76% were transitions and 24% were transversions. A subset of SNPs was evaluated by sequence analysis of five RJ and five WL birds. Nine of 12 SNPs were verified in this limited sample, suggesting that a majority of the putative polymorphisms documented in this study represent real SNPs. During full-length sequencing of the 46 RJ/WL clones 100 SNPs were identified, which translated to a frequency of 1.90 SNPs/1000 bp. The number of transitions and transversions were 77% and 23%, respectively, and the proportion of non-synonymous vs. synonymous SNPs was 20% and 80%, respectively. Four large insertions/deletions were identified between the RJ and WL full-length sequences, and they appear to represent different splice variants. PMID:15373743

  9. THE MID-INFRARED AND NEAR-ULTRAVIOLET EXCESS EMISSIONS OF QUIESCENT GALAXIES ON THE RED SEQUENCE

    SciTech Connect

    Ko, Jongwan; Lee, Jong Chul; Hwang, Ho Seong; Sohn, Young-Jong

    2013-04-10

    We study the mid-infrared (IR) and near-ultraviolet (UV) excess emissions of spectroscopically selected quiescent galaxies on the optical red sequence. We use the Wide-field Infrared Survey Explorer mid-IR and Galaxy Evolution Explorer near-UV data for a spectroscopic sample of galaxies in the Sloan Digital Sky Survey Data Release 7 to study the possible connection between quiescent red-sequence galaxies with and without mid-IR/near-UV excess. Among 648 12 {mu}m detected quiescent red-sequence galaxies without H{alpha} emission, 26% and 55% show near-UV and mid-IR excess emissions, respectively. When we consider only bright (M{sub r} < -21.5) galaxies with an early-type morphology, the fraction of galaxies with recent star formation is still 39%. The quiescent red-sequence galaxies with mid-IR and near-UV excess emissions are optically fainter and have slightly smaller D{sub n} 4000 than those without mid-IR and near-UV excess emissions. We also find that mid-IR weighted mean stellar ages of quiescent red-sequence galaxies with mid-IR excess are larger than those with near-UV excess, and smaller than those without mid-IR and near-UV excess. The environmental dependence of the fraction of quiescent red-sequence galaxies with mid-IR and near-UV excess seems strong even though the trends of quiescent red-sequence galaxies with near-UV excess differ from those with mid-IR excess. These results indicate that the recent star formation traced by near-UV ({approx}< 1 Gyr) and mid-IR ({approx}< 2 Gyr) excess is not negligible among nearby, quiescent, red, early-type galaxies. We suggest a possible evolutionary scenario of quiescent red-sequence galaxies from quiescent red-sequence galaxies with near-UV excess to those with mid-IR excess to those without near-UV and mid-IR excess.

  10. Red Sea isolation history suggested by Plio-Pleistocene seismic reflection sequences

    NASA Astrophysics Data System (ADS)

    Mitchell, Neil C.; Ligi, Marco; Rohling, Eelco J.

    2015-11-01

    High evaporation rates in the desert climate of the Red Sea ensure that, during glacial sea level lowstands when water exchange with the Indian Ocean was more restricted, water salinity and δ18 O became unusually extreme. Modeling of the effect on Red Sea sedimentary δ18 O has been used previously to reconstruct relative sea level to 500 ka and now poses the question of whether that sea-level model could be extended if continuous core material of older sediment became available. We attempt to address this question here by examining seismic reflection data. The upper Pleistocene hemipelagic sediments in the Red Sea contain intervals of inorganic aragonite precipitated during supersaturated conditions of sea-level lowstands. Seismic impedance changes associated with boundaries to those aragonite-rich layers appear to explain seismic reflection sequences. A segment of Chirp sediment profiler data from the central Red Sea reveals prominent reflections at ∼1, ∼5, ∼23, ∼26 and ∼36 ms two-way travel time (TWT) from the seabed. Based on depths to the glacial marine isotope stages (MIS) in cores, we relate the upper three reflections to the tops of aragonite-rich layers and hence the sea level rises immediately following MIS 2, 6 and 12. The reflection at 26 ms is related to an unusually rapid fall into MIS 12 predicted by one sea level reconstruction, which may have created an abrupt lower boundary to the MIS 12 aragonite-rich layer. With the aid of seismogram modeling, we tentatively associate the ∼36 ms reflection with the top of an aragonite-rich layer formed during MIS 16. Furthermore, some segments of lower frequency (airgun and sparker) seismic data from the central and southern Red Sea show a lower (earlier) Plio-Pleistocene (PP) interval that is less reflective than the upper (late) PP interval. This implies less variability in sediment impedance and that extreme variability in water salinity did not develop; water exchange with the Indian Ocean

  11. A study on the multicolour evolution of red-sequence galaxy populations: insights from hydrodynamical simulations and semi-analytical models

    NASA Astrophysics Data System (ADS)

    Romeo, A. D.; Kang, Xi; Contini, E.; Sommer-Larsen, J.; Fassbender, R.; Napolitano, N. R.; Antonuccio-Delogu, V.; Gavignaud, I.

    2015-09-01

    Context. By means of our own cosmological-hydrodynamical simulation (SIM) and semi-analytical model (SAM), we studied galaxy population properties in clusters and groups, spanning over ten different bands from the ultraviolet to the near-infrared (NIR), and their evolution since redshift z = 2. Aims: We compare our results in terms of red/blue galaxy fractions and of the luminous-to-faint ratio (LFR) on the red sequence (RS) with recent observational data reaching beyond z = 1.5. Methods: Different selection criteria were tested to retrieve the galaxies that effectively belong to the RS: either by their quiescence degree measured from their specific star formation rate (sSFR; the so-called "dead sequence"), or by their position in a colour-colour plane, which is also a function of sSFR. In both cases, the colour cut and the lower limit magnitude thresholds were let to evolve with redshift so that they would follow the natural shift of the characteristic luminosity in the luminosity function (LF). Results: We find that the Butcher-Oemler effect is wavelength-dependent, with the fraction of blue galaxies increasing more steeply in optical-optical than in NIR-optical colours. Moreover, a steep trend in the blue fraction can only be reproduced when an optically fixed luminosity-selected sample is chosen, while the trend flattens when selecting samples by stellar mass or by an evolving magnitude limit. We also find that the RS-LFR behaviour, highly debated in the literature, is strongly dependent on the galaxy selection function: in particular, the very mild evolution that is recovered when using a mass-selected galaxy sample agrees with values reported for some of the highest redshift-confirmed (proto)clusters. For differences that are attributable to environments, we find that normal groups and (to a lesser extent) cluster outskirts present the highest values of both the star-forming fraction and LFR at low z, while fossil groups and cluster cores have the lowest

  12. First ancient DNA sequences from the Late Pleistocene red deer (Cervus elaphus) in the Crimea, Ukraine

    NASA Astrophysics Data System (ADS)

    Stanković, Ana; Nadachowski, Adam; Doan, Karolina; Stefaniak, Krzysztof; Baca, Mateusz; Socha, Paweł; Wegleński, Piotr; Ridush, Bogdan

    2010-05-01

    The Late Pleistocene has been a period of significant population and species turnover and extinctions among the large mammal fauna. Massive climatic and environmental changes during Pleistocene significantly influenced the distribution and also genetic diversity of plants and animals. The model of glacial refugia and habitat contraction to southern peninsulas in Europe as areas for the survival of temperate animal species during unfavourable Pleistocene glaciations is at present widely accepted. However, both molecular data and the fossil record indicate the presence of northern and perhaps north-eastern refugia in Europe. In recent years, much new palaeontological data have been obtained in the Crimean Peninsula, Ukraine, following extensive investigations. The red deer (Cervus elaphus) samples for aDNA studies were collected in Emine-Bair-Khosar Cave, situated on the north edge of Lower Plateau of the Chatyrdag Massif (Crimean Mountains). The cave is a vertical shaft, which functioned as a huge mega-trap over a long period of time (probably most of the Pleistocene). The bone assemblages provided about 5000 bones belonging to more than 40 species. The C. elaphus bones were collected from three different stratigraphical levels, radiocarbon dated by accelerator mass spectrometry (AMS) method. The bone fragments of four specimens of red deer were used for the DNA isolation and analysis. The mtDNA (Cytochome b) was successfully isolated from three bone fragments and the cytochrome b sequences were amplified by multiplex PCR. The sequences obtained so far allowed for the reconstruction of only preliminary phylogenetic trees. A fragment of metatarsus from level dated to ca. 48,500±2,000 years BP, yielded a sequence of 513 bp, allowing to locate the specimen on the phylogenetic tree within modern C. elaphus specimens from southern and middle Europe. The second bone fragment, a fragment of mandible, collected from level dated approximately to ca. 33,500±400 years BP

  13. A Photometric redshift galaxy catalog from the Red-Sequence Cluster Survey

    SciTech Connect

    Hsieh, Bau-Ching; Yee, H.K.C.; Lin, H.; Gladders, M.D.; /Carnegie Inst. Observ.

    2005-02-01

    The Red-Sequence Cluster Survey (RCS) provides a large and deep photometric catalog of galaxies in the z' and R{sub c} bands for 90 square degrees of sky, and supplemental V and B data have been obtained for 33.6 deg{sup 2}. They compile a photometric redshift catalog from these 4-band data by utilizing the empirical quadratic polynomial photometric redshift fitting technique in combination with CNOC2 and GOODS/HDF-N redshift data. The training set includes 4924 spectral redshifts. The resulting catalog contains more than one million galaxies with photometric redshifts < 1.5 and R{sub c} < 24, giving an rms scatter {delta}({Delta}z) < 0.06 within the redshift range 0.2 < z < 0.5 and {sigma}({Delta}z) < 0.11 for galaxies at 0.0 < z < 1.5. They describe the empirical quadratic polynomial photometric redshift fitting technique which they use to determine the relation between red-shift and photometry. A kd-tree algorithm is used to divide up the sample to improve the accuracy of the catalog. They also present a method for estimating the photometric redshift error for individual galaxies. They show that the redshift distribution of the sample is in excellent agreement with smaller and much deeper photometric and spectroscopic redshift surveys.

  14. Draft Genome Sequence of Colletotrichum falcatum - A Prelude on Screening of Red Rot Pathogen in Sugarcane

    PubMed Central

    Viswanathan, Rasappa; Prasanth, Chandrasekaran Naveen; Malathi, Palaniyandi; Sundar, Amalraj Ramesh

    2016-01-01

    Colletotrichum falcatum, a concealed fungal ascomycete causes red rot, which is a serious disease in sugarcane. It infects economically important stalk tissues, considered as store house of sugar in sugarcane. The study is to find genetic complexities of C. falcatum in establishing this as a stalk infecting pathogen and to decipher the unique lifestyle of this pathogen using NGS technology. We report the draft genome of C. falcatum of about 48.16 Mb in size with 12,270 genes. The genome sequences were compared with other fungal species which revealed that C. falcatum is closely related to C. graminicola and C.sublineola the causal organisms of anthracnose in maize and sorghum. These results brought a new revelation to explore the lifestyle of this unique pathogen which is specialized to infect sugarcane stalk tissues in detail. PMID:26958090

  15. Draft Genome Sequence of Colletotrichum falcatum - A Prelude on Screening of Red Rot Pathogen in Sugarcane.

    PubMed

    Viswanathan, Rasappa; Prasanth, Chandrasekaran Naveen; Malathi, Palaniyandi; Sundar, Amalraj Ramesh

    2016-01-01

    Colletotrichum falcatum, a concealed fungal ascomycete causes red rot, which is a serious disease in sugarcane. It infects economically important stalk tissues, considered as store house of sugar in sugarcane. The study is to find genetic complexities of C. falcatum in establishing this as a stalk infecting pathogen and to decipher the unique lifestyle of this pathogen using NGS technology. We report the draft genome of C. falcatum of about 48.16 Mb in size with 12,270 genes. The genome sequences were compared with other fungal species which revealed that C. falcatum is closely related to C. graminicola and C.sublineola the causal organisms of anthracnose in maize and sorghum. These results brought a new revelation to explore the lifestyle of this unique pathogen which is specialized to infect sugarcane stalk tissues in detail. PMID:26958090

  16. Extracellular DNA amplicon sequencing reveals high levels of benthic eukaryotic diversity in the central Red Sea.

    PubMed

    Pearman, John K; Irigoien, Xabier; Carvalho, Susana

    2016-04-01

    The present study aims to characterize the benthic eukaryotic biodiversity patterns at a coarse taxonomic level in three areas of the central Red Sea (a lagoon, an offshore area in Thuwal and a shallow coastal area near Jeddah) based on extracellular DNA. High-throughput amplicon sequencing targeting the V9 region of the 18S rRNA gene was undertaken for 32 sediment samples. High levels of alpha-diversity were detected with 16,089 operational taxonomic units (OTUs) being identified. The majority of the OTUs were assigned to Metazoa (29.2%), Alveolata (22.4%) and Stramenopiles (17.8%). Stramenopiles (Diatomea) and Alveolata (Ciliophora) were frequent in a lagoon and in shallower coastal stations, whereas metazoans (Arthropoda: Maxillopoda) were dominant in deeper offshore stations. Only 24.6% of total OTUs were shared among all areas. Beta-diversity was generally lower between the lagoon and Jeddah (nearshore) than between either of those and the offshore area, suggesting a nearshore-offshore biodiversity gradient. The current approach allowed for a broad-range of benthic eukaryotic biodiversity to be analysed with significantly less labour than would be required by other traditional taxonomic approaches. Our findings suggest that next generation sequencing techniques have the potential to provide a fast and standardised screening of benthic biodiversity at large spatial and temporal scales. PMID:26525270

  17. High-Throughput Sequencing and De Novo Assembly of Red and Green Forms of the Perilla frutescens var. crispa Transcriptome

    PubMed Central

    Fukushima, Atsushi; Nakamura, Michimi; Suzuki, Hideyuki; Saito, Kazuki; Yamazaki, Mami

    2015-01-01

    Perilla frutescens var. crispa (Labiatae) has two chemo-varietal forms, i.e. red and green forms of perilla, that differ in the production of anthocyanins. To facilitate molecular biological and biochemical studies in perilla-specialized metabolism we used Illumina RNA-sequencing technology in our comprehensive comparison of the transcriptome map of the leaves of red and green forms of perilla. Sequencing generated over 1.2 billion short reads with an average length of 101 nt. De novo transcriptome assembly yielded 47,788 and 47,840 unigenes in the red and green forms of perilla plants, respectively. Comparison of the assembled unigenes and existing perilla cDNA sequences showed highly reliable alignment. All unigenes were annotated with gene ontology (GO) and Enzyme Commission numbers and entered into the Kyoto Encyclopedia of Genes and Genomes. We identified 68 differentially expressed genes (DEGs) in red and green forms of perilla. GO enrichment analysis of the DEGs showed that genes involved in the anthocyanin metabolic process were enriched. Differential expression analysis revealed that the transcript level of anthocyanin biosynthetic unigenes encoding flavonoid 3’-hydroxylase, dihydroflavonol 4-reductase, and anthocyanidin synthase was significantly higher in red perilla, while the transcript level of unigenes encoding limonene synthase was significantly higher in green perilla. Our data serve as a basis for future research on perilla bio-engineering and provide a shortcut for the characterization of new functional genes in P. frutescens. PMID:26070213

  18. Kinematics of faint white dwarfs.

    PubMed

    Luyten, W J

    1978-10-01

    An analysis has been made for solar motion for 128 very faint white dwarfs of color class b or a. While about 40% of these stars may be high-velocity objects, it seems definitely indicated that the luminosity of all of them is considerably lower than that for the "normal" white dwarf of the same color. PMID:16592566

  19. Complete Genome Sequence of Avian Paramyxovirus Strain APMV-6/red-crested pochard/Balkhash/5842/2013 from Kazakhstan

    PubMed Central

    Kydyrmanov, Aidyn; Seidalina, Aigerim; Jenckel, Maria; Starick, Elke; Grund, Christian; Asanova, Saule; Khan, Elizaveta; Daulbayeva, Klara; Kasymbekov, Yermukhammet; Zhumatov, Kainar; Sayatov, Marat; Beer, Martin

    2015-01-01

    An avian paramyxovirus 6 strain was isolated during a wild bird monitoring study in Kazakhstan in 2013. The virus was isolated from a wild duck red-crested pochard (Netta rufina) in southeastern Kazakhstan. Here, we present the complete genome sequence of the virus. PMID:26184926

  20. Survey on viral pathogens in wild red foxes (Vulpes vulpes) in Germany with emphasis on parvoviruses and analysis of a DNA sequence from a red fox parvovirus.

    PubMed Central

    Truyen, U.; Müller, T.; Heidrich, R.; Tackmann, K.; Carmichael, L. E.

    1998-01-01

    The seroprevalence of canine parvovirus (CPV), canine distemper virus (CDV), canine adenovirus (CAV) and canine herpesvirus (CHV) infections in red foxes (Vulpes vulpes) was determined in fox sera collected between 1991 and 1995. A total of 500 sera were selected and the seroprevalences were estimated to be 13% (65 of 500 sera) for CPV, 4.4% (17 of 383 sera) for CDV, 35% (17 of 485 sera) for CAV, and 0.4% (2 of 485 sera) for CHV, respectively. No statistically significant differences were observed between the two (rural and suburban) areas under study. Parvovirus DNA sequences were amplified from tissues of free-ranging foxes and compared to those of prototype viruses from dogs and cats. We report here a parvovirus sequence indicative of a true intermediate between the feline panleukopenia virus-like viruses and the canine parvovirus-like viruses. The red fox parvoviral sequence, therefore, appears to represent a link between those viral groups. The DNA sequence together with a significant seroprevalence of parvovirus infections in foxes supports the hypothesis that the sudden emergence of canine parvovirus in the domestic dog population may have involved the interspecies transmission between wild and domestic carnivores. PMID:9825797

  1. ON THE DEARTH OF COMPACT, MASSIVE, RED SEQUENCE GALAXIES IN THE LOCAL UNIVERSE

    SciTech Connect

    Taylor, Edward N.; Franx, Marijn; Brinchmann, Jarle; Glazebrook, Karl; Van der Wel, Arjen; Van Dokkum, Pieter G

    2010-09-01

    We set out to test the claim that the recently identified population of compact, massive, and quiescent galaxies at z {approx} 2.3 must undergo significant size evolution to match the properties of galaxies found in the local universe. Using data from the Sloan Digital Sky Survey (SDSS; Data Release 7), we have conducted a search for local red sequence galaxies with sizes and masses comparable to those found at z {approx} 2.3. The SDSS spectroscopic target selection algorithm excludes high surface brightness objects; we show that this makes incompleteness a concern for such massive, compact galaxies, particularly for low redshifts (z {approx}< 0.05). We have identified 63 M{sub *}>10{sup 10.7} M{sub sun} ({approx}5 x 10{sup 10} M{sub sun}) red sequence galaxies at 0.066 < z{sub spec} < 0.12 which are smaller than the median size-mass relation by a factor of 2 or more. Consistent with expectations from the virial theorem, the median offset from the mass-velocity dispersion relation for these galaxies is 0.12 dex. We do not, however, find any galaxies with sizes and masses comparable to those observed at z {approx} 2.3, implying a decrease in the comoving number density of these galaxies, at fixed size and mass, by a factor of {approx}>5000. This result cannot be explained by incompleteness: in the 0.066 < z < 0.12 interval, we estimate that the SDSS spectroscopic sample should typically be {approx}>75% complete for galaxies with the sizes and masses seen at high redshift, although for the very smallest galaxies it may be as low as {approx}20%. In order to confirm that the absence of such compact massive galaxies in SDSS is not produced by spectroscopic selection effects, we have also looked for such galaxies in the basic SDSS photometric catalog, using photometric redshifts. While we do find signs of a slight bias against massive, compact galaxies, this analysis suggests that the SDSS spectroscopic sample is missing at most a few objects in the regime we consider

  2. THE RISE AND FALL OF PASSIVE DISK GALAXIES: MORPHOLOGICAL EVOLUTION ALONG THE RED SEQUENCE REVEALED BY COSMOS

    SciTech Connect

    Bundy, Kevin; Hopkins, Philip; Ma, Chung-Pei; Scarlata, Claudia; Capak, Peter; Carollo, C. M.; Oesch, Pascal; Ellis, Richard S.; Salvato, Mara; Scoville, Nick; Drory, Niv; Leauthaud, Alexie; Koekemoer, Anton M.; Murray, Norman; Ilbert, Olivier; Pozzetti, Lucia

    2010-08-20

    The increasing abundance of passive 'red-sequence' galaxies since z {approx} 1-2 is mirrored by a coincident rise in the number of galaxies with spheroidal morphologies. In this paper, however, we show in detail, that, the correspondence between galaxy morphology and color is not perfect, providing insight into the physical origin of this evolution. Using the COSMOS survey, we study a significant population of red-sequence galaxies with disk-like morphologies. These passive disks typically have Sa-Sb morphological types with large bulges, but they are not confined to dense environments. They represent nearly one-half of all red-sequence galaxies and dominate at lower masses ({approx}<10{sup 10} M{sub sun}) where they are increasingly disk-dominated. As a function of time, the abundance of passive disks with M {sub *} {approx}< 10{sup 11} M{sub sun} increases, but not as fast as red-sequence spheroidals in the same mass range. At higher mass, the passive disk population has declined since z {approx} 1, likely because they transform into spheroidals. Based on these trends, we estimate that as much as 60% of galaxies transitioning onto the red sequence evolve through a passive disk phase. The origin of passive disks therefore has broad implications for our understanding of how star formation shuts down. Because passive disks tend to be more bulge-dominated than their star-forming counterparts, a simple fading of blue disks does not fully explain their origin. We explore the strengths and weaknesses of several more sophisticated explanations, including environmental effects, internal stabilization, and disk regrowth during gas-rich mergers. While previous work has sought to explain color and morphological transformations with a single process, these observations open the way to new insight by highlighting the fact that galaxy evolution may actually proceed through several separate stages.

  3. The nature of faint emission-line galaxies

    NASA Technical Reports Server (NTRS)

    Smetanka, John J.

    1993-01-01

    One of the results of faint galaxy redshift surveys is the increased fraction of galaxies which have strong emission-line spectra. These faint surveys find that roughly 50 percent of the galaxies have an equivalent width of (OII), W sub 3727, greater than 20 A while this fraction is less than 20 percent in the DARS survey. This has been interpreted as evidence for strong evolution in the galaxy population at redshifts less than 0.5. In order to further investigate the properties of the galaxies in faint redshift surveys, two important factors must be addressed. The first is the observed correlation between color, luminosity, and W sub 3727. There is a correlation between color and the strength of emission lines, bluer galaxies having stronger emission features, as evident for Markarian galaxies and for galaxies in Kennicutt's spectrophotometric atlas. This correlation also applies galaxies in faint redshift surveys. In addition, low luminosity galaxies have a larger average W sub 3727 (and bluer colors) than higher luminosity galaxies. This is illustrated for Kennicutt's low z late-type galaxies, for the Durham Faint Surveys, and for galaxies in SA68. The second factor which must be incorporated into any interpretation of the faint emission galaxies is the different luminosity functions for galaxies depending on color. This is usually modeled by varying M* for different color classes (or morphological types); however, the shape of the luminosity function is different for galaxies with different colors. Low luminosity, blue galaxies have a much larger number density than low luminosity, red galaxies. Furthermore, the low luminosity end of the blue galaxy luminosity function is not well fit by a Schechter function. These two factors have been included in a very simple, no-evolution, model for the galaxy population. This model uses the luminosity functions from Shanks (1990) and spectral energy distributions (SED's) from Bruzual (1988). W sub 3727 is predicted using

  4. Chemical overprint on the natural remanent magnetization of a subtropical red soil sequence in the Bose Basin, southern China

    NASA Astrophysics Data System (ADS)

    Deng, Chenglong; Liu, Qingsong; Wang, Wei; Liu, Caicai

    2007-11-01

    We present a high-resolution paleomagnetic investigation of the subtropical red soil sequence at the Damei section, Bose Basin, southern China. Maghemite with low coercivities and fine-grained hematite with high coercivities but relatively low unblocking temperatures were identified as main carriers of the natural remanent magnetization (NRM). Strong chemical weathering occurring under subtropical climatic conditions in southern China led to a chemical remanent magnetization (CRM) overprint that is sufficiently strong to mask the primary NRM. Analysis of the Bose Basin soil sequence indicates that the CRM has a large lock-in depth (>4 m). This example shows that magnetostratigraphic studies on red soil sequences in subtropical-tropical southern China should be interpreted with caution.

  5. Complete Sequence and Analysis of Plastid Genomes of Two Economically Important Red Algae: Pyropia haitanensis and Pyropia yezoensis

    PubMed Central

    Wang, Li; Mao, Yunxiang; Kong, Fanna; Li, Guiyang; Ma, Fei; Zhang, Baolong; Sun, Peipei; Bi, Guiqi; Zhang, Fangfang; Xue, Hongfan; Cao, Min

    2013-01-01

    Background Pyropia haitanensis and P. yezoensis are two economically important marine crops that are also considered to be research models to study the physiological ecology of intertidal seaweed communities, evolutionary biology of plastids, and the origins of sexual reproduction. This plastid genome information will facilitate study of breeding, population genetics and phylogenetics. Principal Findings We have fully sequenced using next-generation sequencing the circular plastid genomes of P. hatanensis (195,597 bp) and P. yezoensis (191,975 bp), the largest of all the plastid genomes of the red lineage sequenced to date. Organization and gene contents of the two plastids were similar, with 211–213 protein-coding genes (including 29–31 unknown-function ORFs), 37 tRNA genes, and 6 ribosomal RNA genes, suggesting a largest coding capacity in the red lineage. In each genome, 14 protein genes overlapped and no interrupted genes were found, indicating a high degree of genomic condensation. Pyropia maintain an ancient gene content and conserved gene clusters in their plastid genomes, containing nearly complete repertoires of the plastid genes known in photosynthetic eukaryotes. Similarity analysis based on the whole plastid genome sequences showed the distance between P. haitanensis and P. yezoensis (0.146) was much smaller than that of Porphyra purpurea and P. haitanensis (0.250), and P. yezoensis (0.251); this supports re-grouping the two species in a resurrected genus Pyropia while maintaining P. purpurea in genus Porphyra. Phylogenetic analysis supports a sister relationship between Bangiophyceae and Florideophyceae, though precise phylogenetic relationships between multicellular red alage and chromists were not fully resolved. Conclusions These results indicate that Pyropia have compact plastid genomes. Large coding capacity and long intergenic regions contribute to the size of the largest plastid genomes reported for the red lineage. Possessing the largest

  6. Faint Object Spectrograph (FOS) calibration

    NASA Technical Reports Server (NTRS)

    Harms, R. J.; Beaver, E. A.; Burbidge, E. M.; Angel, J. R. P.; Bartko, F.; Mccoy, J.; Ripp, L.; Bohlin, R.; Davidsen, A. F.; Ford, H.

    1982-01-01

    The Faint Object Spectrograph (FOS) designed for use with The Space Telescope (ST), is currently preparing for instrument assembly, integration, alignment, and calibration. Nearly all optical and detector elements have been completed and calibrated, and selection of flight detectors and all but a few optical elements has been made. Calibration results for the flight detectors and optics are presented, and plans for forthcoming system calibration are briefly described.

  7. HUBBLE'S SEARCH FOR FAINT FIELD STARS IN GALACTIC HALO

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Left A NASA Hubble Space Telescope image of a randomly selected area of sky taken to search for faint red stars that might constitute dark matter in our Milky Way Galaxy. (Dark matter is material of an unknown type that makes up most of the mass of our galaxy). If the dark matter in our Galaxy was made of faint red stars -- as many scientists have previously conjectured -- then about 38 such stars should have been visible in this HST image. The simulated stars (diamond-shaped symbols), based on theoretical calculations, illustrate what scientists would have seen if the dark matter were locked-up in faint red stars. These surprising results rule out dim stars as an explanation for dark matter in our Galaxy. Right The unmodified HST image shows the region is actually so devoid of stars that far more distant background galaxies can easily be seen. The field is in the constellation Eridanus, far outside the plane of our Milky Way Galaxy. This region was chosen to highlight stars in the galactic halo, where dark matter exists, and to avoid the contribution of faint stars in the plane of the Galaxy. Technical Information: The image was constructed from seven exposures totaling almost three hours of searching by HST. The field shown is about 1.5 arc-minutes across. The image was taken in near-infrared light (814 nm) with the Wide Field Planetary Camera 2, on Feb 8, 1994. This observation is part of the HST parallel observing program. Credit: J Bahcall, Institute for Advance Study, Princeton and NASA

  8. Complete mitochondrial genome sequence of a Hungarian red deer (Cervus elaphus hippelaphus) from high-throughput sequencing data and its phylogenetic position within the family Cervidae.

    PubMed

    Frank, Krisztián; Barta, Endre; Bana, Nóra Á; Nagy, János; Horn, Péter; Orosz, László; Stéger, Viktor

    2016-06-01

    Recently, there has been considerable interest in genetic differentiation in the Cervidae family. A common tool used to determine genetic variation in different species, breeds and populations is mitochondrial DNA analysis, which can be used to estimate phylogenetic relationships among animal taxa and for molecular phylogenetic evolution analysis. With the development of sequencing technology, more and more mitochondrial sequences have been made available in public databases, including whole mitochondrial DNA sequences. These data have been used for phylogenetic analysis of animal species, and for studies of evolutionary processes. We determined the complete mitochondrial genome of a Central European red deer, Cervus elaphus hippelaphus, from Hungary by a next generation sequencing technology. The mitochondrial genome is 16 354 bp in length and contains 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region, all of which are arranged similar as in other vertebrates. We made phylogenetic analyses with the new sequence and 76 available mitochondrial sequences of Cervidae, using Bos taurus mitochondrial sequence as outgroup. We used 'neighbor joining' and 'maximum likelihood' methods on whole mitochondrial genome sequences; the consensus phylogenetic trees supported monophyly of the family Cervidae; it was divided into two subfamilies, Cervinae and Capreolinae, and five tribes, Cervini, Muntiacini, Alceini, Odocoileini, and Capreolini. The evolutionary structure of the family Cervidae can be reconstructed by phylogenetic analysis based on whole mitochondrial genomes; which method could be used broadly in phylogenetic evolutionary analysis of animal taxa. PMID:27165525

  9. Magneto- and cyclostratigraphy in the red clay sequence: New age model and paleoclimatic implication for the eastern Chinese Loess Plateau

    NASA Astrophysics Data System (ADS)

    Anwar, Taslima; Kravchinsky, Vadim A.; Zhang, Rui

    2015-10-01

    The Chinese Loess Plateau red clay sequences display a continuous alternation of sedimentary cycles that represent recurrent climatic fluctuations from 2.58 Ma to the Miocene. Deciphering such a record can provide us with vital information on global and Asian climatic variations. Lack of fossils and failure of absolute dating methods made magnetostratigraphy a leading method to build age models for the red clay sequences. Here we test the magnetostratigraphic age model against cyclostratigraphy. For this purpose we investigate the climate cyclicity recorded in magnetic susceptibility and sedimentary grain size in a red clay section previously dated 11 Myr old with magnetostratigraphy alone. Magnetostratigraphy dating based on only visual correlation could potentially lead to erroneous age model. In this study the correlation is executed through the iteration procedure until it is supported by cyclostratigraphy; i.e., Milankovitch cycles are resolved in the best possible manner. Our new age model provides an age of 5.2 Ma for the Shilou profile. Based on the new age model, wavelet analysis reveals the well-preserved 400 kyr and possible 100 kyr eccentricity cycles on the eastern Chinese Loess Plateau. Further, paleomonsoon evolution during 2.58-5.2 Ma is reconstructed and divided into three intervals (2.58-3.6 Ma, 3.6-4.5 Ma, and 4.5-5.2 Ma). The upper part, the youngest stage, is characterized by a relatively intensified summer monsoon, the middle stage reflects an intensification of the winter monsoon and aridification in Asia, and the earliest stage indicates that summer and winter monsoon cycles may have rapidly altered. The use of cyclostratigraphy along with magnetostratigraphy gives us an effective method of dating red clay sequences, and our results imply that many presently published age models for the red clay deposits should be perhaps re-evaluated.

  10. Fainting

    MedlinePlus

    ... kids: drink plenty of fluids, especially in hot weather or during physical activity take frequent breaks and move around as much as possible when sitting or standing for long periods of time slowly breathe into a paper bag ... Foundation, iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and Clipart. ...

  11. Faintness

    MedlinePlus

    ... decisions about when and where they should receive healthcare. Unfortunately, most people lack the medical knowledge needed to make these decisions safely. FreeMD.com is powered by a computer program that performs symptom triage. The goal of ...

  12. Fainting

    MedlinePlus

    ... severely dehydrated ) Standing up very suddenly from a lying position Less common but more serious reasons for ... avoid or change them. Get up from a lying or seated position slowly. If having blood drawn ...

  13. Classification, Naming and Evolutionary History of Glycosyltransferases from Sequenced Green and Red Algal Genomes

    PubMed Central

    Ulvskov, Peter; Paiva, Dionisio Soares; Domozych, David; Harholt, Jesper

    2013-01-01

    The Archaeplastida consists of three lineages, Rhodophyta, Virideplantae and Glaucophyta. The extracellular matrix of most members of the Rhodophyta and Viridiplantae consists of carbohydrate-based or a highly glycosylated protein-based cell wall while the Glaucophyte covering is poorly resolved. In order to elucidate possible evolutionary links between the three advanced lineages in Archaeplastida, a genomic analysis was initiated. Fully sequenced genomes from the Rhodophyta and Virideplantae and the well-defined CAZy database on glycosyltransferases were included in the analysis. The number of glycosyltransferases found in the Rhodophyta and Chlorophyta are generally much lower then in land plants (Embryophyta). Three specific features exhibited by land plants increase the number of glycosyltransferases in their genomes: (1) cell wall biosynthesis, the more complex land plant cell walls require a larger number of glycosyltransferases for biosynthesis, (2) a richer set of protein glycosylation, and (3) glycosylation of secondary metabolites, demonstrated by a large proportion of family GT1 being involved in secondary metabolite biosynthesis. In a comparative analysis of polysaccharide biosynthesis amongst the taxa of this study, clear distinctions or similarities were observed in (1) N-linked protein glycosylation, i.e., Chlorophyta has different mannosylation and glucosylation patterns, (2) GPI anchor biosynthesis, which is apparently missing in the Rhodophyta and truncated in the Chlorophyta, (3) cell wall biosynthesis, where the land plants have unique cell wall related polymers not found in green and red algae, and (4) O-linked glycosylation where comprehensive orthology was observed in glycosylation between the Chlorophyta and land plants but not between the target proteins. PMID:24146880

  14. Classification, naming and evolutionary history of glycosyltransferases from sequenced green and red algal genomes.

    PubMed

    Ulvskov, Peter; Paiva, Dionisio Soares; Domozych, David; Harholt, Jesper

    2013-01-01

    The Archaeplastida consists of three lineages, Rhodophyta, Virideplantae and Glaucophyta. The extracellular matrix of most members of the Rhodophyta and Viridiplantae consists of carbohydrate-based or a highly glycosylated protein-based cell wall while the Glaucophyte covering is poorly resolved. In order to elucidate possible evolutionary links between the three advanced lineages in Archaeplastida, a genomic analysis was initiated. Fully sequenced genomes from the Rhodophyta and Virideplantae and the well-defined CAZy database on glycosyltransferases were included in the analysis. The number of glycosyltransferases found in the Rhodophyta and Chlorophyta are generally much lower then in land plants (Embryophyta). Three specific features exhibited by land plants increase the number of glycosyltransferases in their genomes: (1) cell wall biosynthesis, the more complex land plant cell walls require a larger number of glycosyltransferases for biosynthesis, (2) a richer set of protein glycosylation, and (3) glycosylation of secondary metabolites, demonstrated by a large proportion of family GT1 being involved in secondary metabolite biosynthesis. In a comparative analysis of polysaccharide biosynthesis amongst the taxa of this study, clear distinctions or similarities were observed in (1) N-linked protein glycosylation, i.e., Chlorophyta has different mannosylation and glucosylation patterns, (2) GPI anchor biosynthesis, which is apparently missing in the Rhodophyta and truncated in the Chlorophyta, (3) cell wall biosynthesis, where the land plants have unique cell wall related polymers not found in green and red algae, and (4) O-linked glycosylation where comprehensive orthology was observed in glycosylation between the Chlorophyta and land plants but not between the target proteins. PMID:24146880

  15. Complete sequence of the mitochondrial DNA of the red alga Porphyra purpurea. Cyanobacterial introns and shared ancestry of red and green algae.

    PubMed Central

    Burger, G; Saint-Louis, D; Gray, M W; Lang, B F

    1999-01-01

    The mitochondrial DNA (mtDNA) of Porphyra purpurea, a circular-mapping genome of 36,753 bp, has been completely sequenced. A total of 57 densely packed genes has been identified, including the basic set typically found in animals and fungi, as well as seven genes characteristic of protist and plant mtDNAs and specifying ribosomal proteins and subunits of succinate:ubiquinone oxidoreductase. The mitochondrial large subunit rRNA gene contains two group II introns that are extraordinarily similar to those found in the cyanobacterium Calothrix sp, suggesting a recent lateral intron transfer between a bacterial and a mitochondrial genome. Notable features of P. purpurea mtDNA include the presence of two 291-bp inverted repeats that likely mediate homologous recombination, resulting in genome rearrangement, and of numerous sequence polymorphisms in the coding and intergenic regions. Comparative analysis of red algal mitochondrial genomes from five different, evolutionarily distant orders reveals that rhodophyte mtDNAs are unusually uniform in size and gene order. Finally, phylogenetic analyses provide strong evidence that red algae share a common ancestry with green algae and plants. PMID:10488235

  16. MULTIPLE HYDROXYCINNAMOYL TRANSFERASES FROM RED CLOVER DIFFER IN SEQUENCE, EXPRESSION PATTERN, AND ENZYMATIC ACTIVITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phenylpropanoid o-diphenols accumulate in tissues of many plants, functioning as defensive molecules and antioxidants. Red clover leaves accumulate high levels of two o-diphenols, phasalic acid [2-O-(caffeoyl)-L-malate, see Fig. 1] and clovamide [N-(caffeoyl)-L-DOPA]. In red clover, post-harvest oxi...

  17. Genome Sequence of Acidovorax avenae Strain T10_61 Associated with Sugarcane Red Stripe in Argentina

    PubMed Central

    Fontana, Cecilia A.; Bassi, Daniela; Puglisi, Edoardo; Salazar, Sergio M.; Vignolo, Graciela M.; Coccocelli, Pier S.

    2016-01-01

    Red stripe of sugarcane in Argentina is a bacterial disease caused by Acidovorax avenae. The genome sequence from the first isolate of this bacterium in Argentina is presented here. The draft genome of the A. avenae T10_61 strain contains 5,646,552 bp and has a G+C content of 68.6 mol%. PMID:26847889

  18. The UV-Optical Galaxy Color-Magnitude Diagram. III. Constraints on Evolution from the Blue to the Red Sequence

    NASA Astrophysics Data System (ADS)

    Martin, D. Christopher; Wyder, Ted K.; Schiminovich, David; Barlow, Tom A.; Forster, Karl; Friedman, Peter G.; Morrissey, Patrick; Neff, Susan G.; Seibert, Mark; Small, Todd; Welsh, Barry Y.; Bianchi, Luciana; Donas, José; Heckman, Timothy M.; Lee, Young-Wook; Madore, Barry F.; Milliard, Bruno; Rich, R. Michael; Szalay, Alex S.; Yi, Sukyoung K.

    2007-12-01

    We introduce a new quantity, the mass flux density of galaxies evolving from the blue sequence to the red sequence. We propose a simple technique for constraining this mass flux using the volume-corrected number density in the extinction-corrected UV-optical color-magnitude distribution, the stellar age indexes HδA and Dn(4000), and a simple prescription for spectral evolution using a quenched star formation history. We exploit the excellent separation of red and blue sequences in the NUV-r band Hess function. The final value we measure, ρT˙=0.033 Msolar yr-1 Mpc-3, is strictly speaking an upper limit due to the possible contributions of bursting, composite, and extincted galaxies. However, it compares favorably with estimates of the average mass flux that we make based on the red luminosity function evolution derived from the DEEP2 and COMBO-17 surveys, ρ˙R=+0.034 Msolar yr-1 Mpc-3. We find that the blue sequence mass has remained roughly constant since z=1 (ρB˙~=0.01 Msolar yr-1 Mpc-3, but the average on-going star formation of ρ˙SF~=0.037 Msolar yr-1 Mpc-3 over 0sequence. We explore the nature of the galaxies in the transition zone with particular attention to the frequency and impact of active galactic nuclei (AGNs). The AGN fraction peaks in the transition zone. We find circumstantial, albeit weak evidence that the quench rates are higher in higher luminosity AGNs.

  19. THE RED-SEQUENCE CLUSTER SURVEY-2 (RCS-2): SURVEY DETAILS AND PHOTOMETRIC CATALOG CONSTRUCTION

    SciTech Connect

    Gilbank, David G.; Gladders, M. D.; Yee, H. K. C.; Hsieh, B. C.

    2011-03-15

    The second Red-sequence Cluster Survey (RCS-2) is a {approx}1000 deg{sup 2}, multi-color imaging survey using the square-degree imager, MegaCam, on the Canada-France-Hawaii Telescope. It is designed to detect clusters of galaxies over the redshift range 0.1 {approx}< z {approx}< 1. The primary aim is to build a statistically complete, large ({approx}10{sup 4}) sample of clusters, covering a sufficiently long redshift baseline to be able to place constraints on cosmological parameters via the evolution of the cluster mass function. Other main science goals include building a large sample of high surface brightness, strongly gravitationally lensed arcs associated with these clusters, and an unprecedented sample of several tens of thousands of galaxy clusters and groups, spanning a large range of halo mass, with which to study the properties and evolution of their member galaxies. This paper describes the design of the survey and the methodology for acquiring, reducing, and calibrating the data for the production of high-precision photometric catalogs. We describe the method for calibrating our griz imaging data using the colors of the stellar locus and overlapping Two Micron All Sky Survey photometry. This yields an absolute accuracy of <0.03 mag on any color and {approx}0.05 mag in the r-band magnitude, verified with respect to the Sloan Digital Sky Survey (SDSS). Our astrometric calibration is accurate to <<0.''3 from comparison with SDSS positions. RCS-2 reaches average 5{sigma} point-source limiting magnitudes of griz = [24.4, 24.3, 23.7, 22.8], approximately 1-2 mag deeper than the SDSS. Due to the queue-scheduled nature of the observations, the data are highly uniform and taken in excellent seeing, mostly FWHM {approx}< 0.''7 in the r band. In addition to the main science goals just described, these data form the basis for a number of other planned and ongoing projects (including the WiggleZ survey), making RCS-2 an important next-generation imaging survey.

  20. Freeze, flight, fight, fright, faint: adaptationist perspectives on the acute stress response spectrum.

    PubMed

    Bracha, H Stefan

    2004-09-01

    This article reviews the existing evolutionary perspectives on the acute stress response habitual faintness and blood-injection-injury type-specific phobia (BIITS phobia). In this article, an alternative evolutionary perspective, based on recent advances in evolutionary psychology, is proposed. Specifically, that fear-induced faintness (eg, fainting following the sight of a syringe, blood, or following a trivial skin injury) is a distinct Homo sapiens-specific extreme-stress survival response to an inescapable threat. The article suggests that faintness evolved in response to middle paleolithic intra-group and inter-group violence (of con-specifics) rather than as a pan-mammalian defense response, as is presently assumed. Based on recent literature, freeze, flight, fight, fright, faint provides a more complete description of the human acute stress response sequence than current descriptions. Faintness, one of three primary physiological reactions involved in BIITS phobia, is extremely rare in other phobias. Since heritability estimates are higher for faintness than for fears or phobias, the author suggests that trait-faintness may be a useful complement to trait-anxiety as an endophenotype in research on the human fear circuitry. Some implications for the forthcoming Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition as well as for clinical, health services, and transcriptomic research are briefly discussed. PMID:15337864

  1. TESTING SCALING RELATIONS FOR SOLAR-LIKE OSCILLATIONS FROM THE MAIN SEQUENCE TO RED GIANTS USING KEPLER DATA

    SciTech Connect

    Huber, D.; Bedding, T. R.; Stello, D.; Hekker, S.; Mathur, S.; Mosser, B.; Verner, G. A.; Elsworth, Y. P.; Hale, S. J.; Chaplin, W. J.; Bonanno, A.; Buzasi, D. L.; Campante, T. L.; Kallinger, T.; Silva Aguirre, V.; De Ridder, J.; Garcia, R. A.; Frandsen, S.; Houdek, G.; and others

    2011-12-20

    We have analyzed solar-like oscillations in {approx}1700 stars observed by the Kepler Mission, spanning from the main sequence to the red clump. Using evolutionary models, we test asteroseismic scaling relations for the frequency of maximum power ({nu}{sub max}), the large frequency separation ({Delta}{nu}), and oscillation amplitudes. We show that the difference of the {Delta}{nu}-{nu}{sub max} relation for unevolved and evolved stars can be explained by different distributions in effective temperature and stellar mass, in agreement with what is expected from scaling relations. For oscillation amplitudes, we show that neither (L/M){sup s} scaling nor the revised scaling relation by Kjeldsen and Bedding is accurate for red-giant stars, and demonstrate that a revised scaling relation with a separate luminosity-mass dependence can be used to calculate amplitudes from the main sequence to red giants to a precision of {approx}25%. The residuals show an offset particularly for unevolved stars, suggesting that an additional physical dependency is necessary to fully reproduce the observed amplitudes. We investigate correlations between amplitudes and stellar activity, and find evidence that the effect of amplitude suppression is most pronounced for subgiant stars. Finally, we test the location of the cool edge of the instability strip in the Hertzsprung-Russell diagram using solar-like oscillations and find the detections in the hottest stars compatible with a domain of hybrid stochastically excited and opacity driven pulsation.

  2. The evolutionary paths among galaxy types on the Red Sequence at 0.3

    NASA Astrophysics Data System (ADS)

    Eliche-Moral, M. C.; Prieto, M.; Balcells, M.; Abreu, D.; Barro, G.; Cristóbal-Hornillos, D.; Domínguez Palmero, L.; Erwin, P.; Gallego, J.; Guzmán, R.; Hempel, A.; López-Sanjuan, C.; Pérez-González, P. G.; Zamorano, J.

    2013-05-01

    We have studied the main evolutionary paths among the galaxy types residing on the massive end of the Red Sequence and nearby locations on the Green Valley during the last ~9 Gyr. The morphological and star formation properties of a sample of these galaxies at 0.35×10^10 M_⊙ have been analysed. We present direct observational evidence for the first time of the existence of two main evolutionary paths among the different red galaxy types since z~1.5, which provide some clues on the nature of the processes that have governed the assembly of present-day massive quiescent galaxies. The results are in excellent agreement with the hierarchical evolutionary framework proposed in the Eliche-Moral et al. (2010) model. Data from SHARDS (one of the ESO/GTC Large Programmes approved in 2009A) will complement and improve the present findings, shedding some light into many of the still unsettled questions concerning the migration of galaxies from the Blue Cloud to the Red Sequence at z<1.5.

  3. Development and transferability of black and red raspberry microsatellite markers from short-read sequences

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The advent of next-generation sequencing technologies has been a boon to the cost-effective development of molecular markers, particularly in non-model species. Here, we demonstrate the efficiency of microsatellite or simple sequence repeat (SSR) marker development from short-read sequences using th...

  4. Sediment budget as affected by construction of a sequence of dams in the lower Red River, Viet Nam

    NASA Astrophysics Data System (ADS)

    Lu, Xi Xi; Oeurng, Chantha; Le, Thi Phuong Quynh; Thuy, Duong Thi

    2015-11-01

    Dam construction is one of the main factors resulting in riverine sediment changes, which in turn cause river degradation or aggradation downstream. The main objective of this work is to examine the sediment budget affected by a sequence of dams constructed upstream in the lower reach of the Red River. The study is based on the longer-term annual data (1960-2010) with a complementary daily water and sediment data set (2008-2010). The results showed that the stretch of the river changed from sediment surplus (suggesting possible deposition processes) into sediment deficit (possible erosion processes) after the first dam (Thac Ba Dam) was constructed in 1972 and changed back to deposition after the second dam (Hoa Binh Dam) was constructed in 1985. The annual sediment deposition varied between 1.9 Mt/y and 46.7 Mt/y with an annual mean value of 22.9 Mt/y (1985-2010). The sediment deposition at the lower reach of the Red River would accelerate river aggradation which would change river channel capacity in the downstream of the Red River. The depositional processes could be sustained or changed back to erosional processes after more dams (the amount of sediment deposit was much less after the latest two dams Tuyen Quang Dam in 2009 and Sonla Dam in 2010) are constructed, depending on the water and sediment dynamics. This study revealed that the erosional and depositional processes could be shifted for the same stretch of river as affected by a sequence of dams and provides useful insights in river management in order to reduce flood frequency along the lower reach of the Red River.

  5. Mitochondrial DNA sequence analyses and phylogenetic relationships among two Nigerian goat breeds and the South African Kalahari Red.

    PubMed

    Awotunde, Esther O; Bemji, Martha N; Olowofeso, Olajide; James, Ikechukwu J; Ajayi, O O; Adebambo, Ayotunde O

    2015-01-01

    The first hypervariable (HV1) region of mitochondrial DNA (mtDNA) of two popular Nigerian goat breeds: West African Dwarf (WAD) (n=35) and Red Sokoto (RS) (n=37) and one exotic breed: Kalahari Red (KR) (n=38) imported from South Africa were sequenced to investigate sequence diversity, genetic structure, origin, and demographic history of the populations. A total of 68 polymorphic sites were found in 110 sequences that grouped into 68 haplotypes. Average haplotype and nucleotide diversities for all breeds were 0.982±0.005 and 0.02350±0.00213, respectively. Phylogenetic analysis revealed two mtDNA lineages (A and B). Lineage A was predominant and included all haplotypes from WAD and RS and 5 out of 11 haplotypes of KR goats. The remaining haplotypes (6) of KR belong to lineage B. The analysis of molecular variance revealed a high-within breed genetic variance of 82.4% and a low-between breed genetic variance of 17.6%. The three breeds clustered with Capra aegagrus as their wild ancestor. Mismatch distribution analysis showed that WAD, RS and haplogroup A have experienced population expansion events. The study has revealed very high diversity within the three breeds which are not strongly separated from each other based on mtDNA analysis. The information obtained on the genetic structure of the breeds will be useful in planning improvement and conservation programs for the local populations. PMID:25695640

  6. Deep COI sequencing of standardized benthic samples unveils overlooked diversity of Jordanian coral reefs in the northern Red Sea.

    PubMed

    Al-Rshaidat, Mamoon M D; Snider, Allison; Rosebraugh, Sydney; Devine, Amanda M; Devine, Thomas D; Plaisance, Laetitia; Knowlton, Nancy; Leray, Matthieu

    2016-09-01

    High-throughput sequencing (HTS) of DNA barcodes (metabarcoding), particularly when combined with standardized sampling protocols, is one of the most promising approaches for censusing overlooked cryptic invertebrate communities. We present biodiversity estimates based on sequencing of the cytochrome c oxidase subunit 1 (COI) gene for coral reefs of the Gulf of Aqaba, a semi-enclosed system in the northern Red Sea. Samples were obtained from standardized sampling devices (Autonomous Reef Monitoring Structures (ARMS)) deployed for 18 months. DNA barcoding of non-sessile specimens >2 mm revealed 83 OTUs in six phyla, of which only 25% matched a reference sequence in public databases. Metabarcoding of the 2 mm - 500 μm and sessile bulk fractions revealed 1197 OTUs in 15 animal phyla, of which only 4.9% matched reference barcodes. These results highlight the scarcity of COI data for cryptobenthic organisms of the Red Sea. Compared with data obtained using similar methods, our results suggest that Gulf of Aqaba reefs are less diverse than two Pacific coral reefs but much more diverse than an Atlantic oyster reef at a similar latitude. The standardized approaches used here show promise for establishing baseline data on biodiversity, monitoring the impacts of environmental change, and quantifying patterns of diversity at regional and global scales. PMID:27584940

  7. Faint dwarfs in nearby groups

    SciTech Connect

    Speller, Ryan; Taylor, James E. E-mail: taylor@uwaterloo.ca

    2014-06-20

    The number and distribution of dwarf satellite galaxies remain a critical test of cold dark matter-dominated structure formation on small scales. Until recently, observational information about galaxy formation on these scales has been limited mainly to the Local Group. We have searched for faint analogues of Local Group dwarfs around nearby bright galaxies, using a spatial clustering analysis of the photometric catalog of the Sloan Digital Sky Survey (SDSS) Data Release 8. Several other recent searches of SDSS have detected clustered satellite populations down to Δm{sub r} ≡ (m{sub r,} {sub sat} – m{sub r,} {sub main}) ∼ 6-8, using photometric redshifts to reduce background contamination. SDSS photometric redshifts are relatively imprecise, however, for faint and nearby galaxies. Instead, we use angular size to select potential nearby dwarfs and consider only the nearest isolated bright galaxies as primaries. As a result, we are able to detect an excess clustering signal from companions down to Δm{sub r} = 12, 4 mag fainter than most recent studies. We detect an overdensity of objects at separations <400 kpc, corresponding to about 4.6 ± 0.5 satellites per central galaxy, consistent with the satellite abundance expected from the Local Group, given our selection function. Although the sample of satellites detected is incomplete by construction, since it excludes the least and most compact dwarfs, this detection provides a lower bound on the average satellite luminosity function, down to luminosities corresponding to the faintest ''classical'' dwarfs of the Local Group.

  8. The lambda red proteins promote efficient recombination between diverged sequences: implications for bacteriophage genome mosaicism.

    PubMed

    Martinsohn, Jann T; Radman, Miroslav; Petit, Marie-Agnès

    2008-05-01

    Genome mosaicism in temperate bacterial viruses (bacteriophages) is so great that it obscures their phylogeny at the genome level. However, the precise molecular processes underlying this mosaicism are unknown. Illegitimate recombination has been proposed, but homeologous recombination could also be at play. To test this, we have measured the efficiency of homeologous recombination between diverged oxa gene pairs inserted into lambda. High yields of recombinants between 22% diverged genes have been obtained when the virus Red Gam pathway was active, and 100 fold less when the host Escherichia coli RecABCD pathway was active. The recombination editing proteins, MutS and UvrD, showed only marginal effects on lambda recombination. Thus, escape from host editing contributes to the high proficiency of virus recombination. Moreover, our bioinformatics study suggests that homeologous recombination between similar lambdoid viruses has created part of their mosaicism. We therefore propose that the remarkable propensity of the lambda-encoded Red and Gam proteins to recombine diverged DNA is effectively contributing to mosaicism, and more generally, that a correlation may exist between virus genome mosaicism and the presence of Red/Gam-like systems. PMID:18451987

  9. Source mechanisms of the June 2004 Tabuk earthquake sequence, Eastern Red Sea margin, Kingdom of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Aldamegh, K. S.; Abou Elenean, K. M.; Hussein, H. M.; Rodgers, A. J.

    2009-10-01

    A sequence of earthquakes took place in June 2004 approximately 60 km southeast of Tabuk, Saudi Arabia. The first felt event ( M W = 3.9) occurred on June 9 and caused minor damage in the epicentral area according to the National Earthquake Information Center and the local reports. Another moderate size event occurred on June 22 ( M W = 5.1) and was followed by a few felt aftershocks without any reported damage. This earthquake sequence caused considerable alarm at Tabuk and highlights the fact that damaging earthquakes can occur in this region away from the major plate boundary in the Red Sea. Being the largest well-recorded event in the area for which the digital and broadband records from Saudi Arabia, Egypt, Israel, Jordan, Turkey, Cyprus, and Kuwait are available, it provides an excellent opportunity to study the tectonic process and present day stress field acting on this area. The digital records from these regional networks were used to relocate the largest three events of this sequence. Focal mechanisms were obtained from full waveform inversion and indicate normal faulting mechanisms with two nodal planes oriented NW-SE in parallel to the faults bounding the Tabuk graben and the Red Sea rift axis. These events originated at shallow focal depths of 4-5 km, possibly contributing to the widely felt ground motions. These events offer a unique opportunity to study the active tectonics of the region as well as inform future studies of seismic hazard in northwestern Saudi Arabia, the Gulf of Aqaba, and eastern Egypt.

  10. Paleokarstic phenomena of the Lower Ordovician red bed sequences of the Arbuckle group, southern Oklahoma

    SciTech Connect

    Musselman, J.L. )

    1991-06-01

    Oil and gas production has been reported recently from paleokarstic Arbuckle reservoirs in the Ardmore and Arkoma basin. The West Spring Creek and the Kindblade formations apparently exhibit karstic features. The most extensive surface exposure of these formations is on the southern flank of the Arbuckle anticline along Interstate 35 north of Ardmore, Oklahoma. The lithology is predominantly limestone, ranging from argillaceous mudstone to oolitic and/or bioclastic grainstones. However, minor amounts of sandstone were also observed.These lithologies are characteristic of various peritidal facies. Of particular interest in this outcrop are three distinct red bed zones. Although the zones are part of the repetitive shallowing-upward cycles that characterize the West Spring Creek Formation, ample evidence suggests the red beds represent subaerial exposure surfaces where karstification took place. Many of the thin bedded, rubbly mudstones and wackestones actually represent varieties of breccia commonly associated with karst. Collapse and crackle breccia are most commonly observed. Small solution channels and other vugs are usually completely occluded by calcite cement. However, solution cavities or vugs with diameters larger than 10 cm (3.9 in.) are lined with drusy calcite. Hematite-impregnated sediment occurs as thinly laminated infilling of solution vugs and cavities and also acts as a cementing agent of collapse breccias. Preliminary evidence suggests that karstification processes were active during Arbuckle deposition.

  11. Pedogenic slickensides, indicators of strain and deformation processes in red bed sequences of the Appalachian foreland

    SciTech Connect

    Gray, M.B. ); Nickelsen, R.P. )

    1989-01-01

    Pedogenic slickensides are convex-concave slip surfaces that form during expansion/contraction in expansive clay soils such as Vertisols. In the central Appalachians, they occur near the tops of fining-upward cycles in Paleozoic red beds such as the Bloomsburg, Catskill, and Mauch Chunk Formations. Pedogenic slickensides are found in association with other pedogenic (or paleosol) features such as clay-skinned peds, in situ calcareous nodules, and root impressions. Repeated movements along these shear planes during pedogenesis produce strongly aligned clay particles adjacent to pedogenic slickensides; as a result, they are preserved as discrete fractures throughout diagenesis, compaction, and superimposed tectonic deformation. During whole-rock deformation, pedogenic slickensides segregate penetratively deformed rocks into independent, foliate packets and serve as discontinuities that are followed by later structural features. Because the original morphology of pedogenic slickensides is known, they can be used as crude strain markers.

  12. A comparison of heavy mineral assemblage between the loess and the Red Clay sequences on the Chinese Loess Plateau

    NASA Astrophysics Data System (ADS)

    Peng, Wenbin; Wang, Zhao; Song, Yougui; Pfaff, Katharina; Luo, Zeng; Nie, Junsheng; Chen, Wenhan

    2016-06-01

    QEMSCAN-based (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) heavy mineral analysis has recently been demonstrated an efficient way to allow a rapid extraction of provenance information from sediments. However, one key issue to correctly obtain a provenance signal using this technique is to clearly separate effects of diagenetic alteration on heavy minerals in sediments, especially in fine-grained loess. Here we compare heavy mineral assemblages of bottom Quaternary loess (L33) and upper Pliocene Red Clay of three sites on the Chinese Loess Plateau (CLP). Two sites (Chaona and Luochuan) with similar modern climate conditions show similar heavy mineral assemblages but contain much less of the unstable heavy mineral amphibole than the drier Xifeng site. This result provides strong evidence supporting that climate-caused diagenesis is an important factor controlling heavy mineral assemblages of fine-grained loess. However, heavy mineral assemblages are similar for loess and paleosol layers deposited after 0.5 Ma on the Chinese Loess Plateau regardless of climate differences, suggesting that time is also a factor controlling heavy mineral assemblages of loess and Red Clay. Our high resolution sampling of the upper Miocene-Pliocene Chaona Red Clay sequence reveals similar heavy mineral compositions with a minor amphibole content, different from the drier Xifeng site results of the same age. This result indicates that the monsoonal climate pattern might have been maintained since the late Miocene. Furthermore, it indicates that the heavy mineral method is promising in tracing provenance for sites northwest of the Xifeng site on the Loess Plateau.

  13. A comparison of zircon U-Pb age results of the Red Clay sequence on the central Chinese Loess Plateau

    PubMed Central

    Gong, Hujun; Nie, Junsheng; Wang, Zhao; Peng, Wenbin; Zhang, Rui; Zhang, Yunxiang

    2016-01-01

    Single grain zircon U-Pb geochronology has demonstrated great potentials in extracting tectonic and atmospheric circulation signal carried by aeolian, fluvial, and fluviolacustrine sediments. A routine in this sort of studies is analyzing 100–150 grains and then compares zircon U-Pb age spectra between the measured sample and the potential sources. Here we compared the zircon U-Pb age results of the late Miocene-Pliocene Red Clay sequence of two neighboring sites from the Chinese Loess Plateau where similar provenance signal is expected. Although the results from the 5.5 Ma sediment support this prediction, the results from the 3 Ma sediment at these two sites differ from each other significantly. These results emphasize the importance of increasing analysis number per sample and combining the zircon U-Pb geochronology with other provenance tools in order to get reliable provenance information. PMID:27538343

  14. A comparison of zircon U-Pb age results of the Red Clay sequence on the central Chinese Loess Plateau.

    PubMed

    Gong, Hujun; Nie, Junsheng; Wang, Zhao; Peng, Wenbin; Zhang, Rui; Zhang, Yunxiang

    2016-01-01

    Single grain zircon U-Pb geochronology has demonstrated great potentials in extracting tectonic and atmospheric circulation signal carried by aeolian, fluvial, and fluviolacustrine sediments. A routine in this sort of studies is analyzing 100-150 grains and then compares zircon U-Pb age spectra between the measured sample and the potential sources. Here we compared the zircon U-Pb age results of the late Miocene-Pliocene Red Clay sequence of two neighboring sites from the Chinese Loess Plateau where similar provenance signal is expected. Although the results from the 5.5 Ma sediment support this prediction, the results from the 3 Ma sediment at these two sites differ from each other significantly. These results emphasize the importance of increasing analysis number per sample and combining the zircon U-Pb geochronology with other provenance tools in order to get reliable provenance information. PMID:27538343

  15. Analysis of rbcL sequences reveals the global biodiversity, community structure, and biogeographical pattern of thermoacidophilic red algae (Cyanidiales).

    PubMed

    Hsieh, Chia-Jung; Zhan, Shing Hei; Lin, Yiching; Tang, Sen-Lin; Liu, Shao-Lun

    2015-08-01

    Thermoacidophilic cyanidia (Cyanidiales) are the primary photosynthetic eukaryotes in volcanic areas. These red algae also serve as important model organisms for studying life in extreme habitats. The global biodiversity and community structure of Cyanidiales remain unclear despite previous sampling efforts. Here, we surveyed the Cyanidiales biodiversity in the Tatun Volcano Group (TVG) area in Taiwan using environmental DNA sequencing. We generated 174 rbcL sequences from eight samples from four regions in the TVG area, and combined them with 239 publicly available rbcL sequences collected worldwide. Species delimita-tion using this large rbcL data set suggested at least 20 Cyanidiales OTUs (operational taxono-mic units) worldwide, almost three times the presently recognized seven species. Results from environmental DNA showed that OTUs in the TVG area were divided into three groups: (i) dominant in hot springs with 92%-99% sequence identity to Galdieria maxima; (ii) largely distributed in drier and more acidic microhabitats with 99% identity to G. partita; and (iii) primarily distributed in cooler microhabitats and lacking identity to known cyanidia species (a novel Cyanidiales lineage). In both global and individual area analyses, we observed greater species diversity in non-aquatic than aquatic habitats. Community structure analysis showed high similarity between the TVG community and West Pacific-Iceland communities, reflecting their geographic proximity to each other. Our study is the first examination of the global species diversity and biogeographic affinity of cyanidia. Additionally, our data illuminate the influence of microhabitat type on Cyanidiales diversity and highlight intriguing questions for future ecological research. PMID:26986790

  16. The Luminosity Distribution at the Bright End of Red-Sequence Galaxies

    NASA Astrophysics Data System (ADS)

    Loh, Y. S.; Strauss, M. A.

    We study the bright end of the distribution of galaxies in fields with Luminous Red Galaxies (LRG) from the Sloan Digital Sky Survey (SDSS). Using 2099 square degree of SDSS imaging data, we search for bright (> L_*) early-type galaxies within 1 Mpc of 12,608 spectroscopic LRG in the volume-limited redshift range 0.12 < z < 0.38. The brightest galaxies within 1 Mpc of LRG are too bright to be consistent with an exponentially decaying luminosity function of other members in the same field. The luminosity gap, M12 between the first and the second-rank galaxy is large(˜ 0.8 mag). When the LRG fields were split into group-like and cluster-like environments, the former gives (1) a more luminous brightest member, and (2) a larger gap M12. The large luminosity gap shows little evolution with redshifts, putting stringent constraints on the scenerio of the growth of Brightest Cluster (or Group) Galaxies by recent cannibalism of cluster/group members.

  17. The bright end of the luminosity function of red sequence galaxies

    NASA Astrophysics Data System (ADS)

    Loh, Yeong-Shang; Strauss, Michael A.

    2006-02-01

    We study the bright end of the luminosity distribution of galaxies in fields with luminous red galaxies (LRG) from the Sloan Digital Sky Survey (SDSS). Using 2099deg2 of SDSS imaging data, we search for luminous (>~L*) early-type galaxies within 1.0h-1Mpc of a volume-limited sample of 12608 spectroscopic LRG in the redshift range 0.12 < z < 0.38. Most of these objects lie in rich environments, with the LRG being the brightest object within 1.0h-1Mpc. The luminosity gap, M12, between the first- and second-ranked galaxies within 1.0h-1Mpc is large (~0.8 mag), substantially larger than can be explained with an exponentially decaying luminosity function of galaxies. The brightest member is less luminous (by 0.1-0.2 mag) and shows a larger gap in LRG selected groups than in cluster-like environments. The large luminosity gap shows little evolution with redshift to z= 0.4, ruling out the scenario that these LRG selected brightest cluster or group galaxies grow by recent cannibalism of cluster members.

  18. Complete genome sequence of the orange-red pigmented, radioresistant Deinococcus proteolyticus type strain (MRPT)

    SciTech Connect

    Copeland, A; Zeytun, Ahmet; Yasawong, Montri; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Mavromatis, K; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, N; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam L; Hauser, Loren John; Jeffries, Cynthia; Brambilla, Evelyne-Marie; Rohde, Manfred; Sikorski, Johannes; Pukall, Rudiger; Goker, Markus; Detter, J. Chris; Woyke, Tanja; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Lapidus, Alla L.

    2012-01-01

    Deinococcus proteolyticus (ex Kobatake et al. 1973) Brook and Murray 1981 is one of currently 47 species in the genus Deinococcus within the family Deinococcaceae. Strain MRPTT was isolated from faeces of Lama glama; it shares with various other species of the genus the extreme radiation resistance, with D. proteolyticus being resistant up to 1.5 Mrad of gamma radiation. Strain MRPT{sup T} is of further interest for its carotenoid pigment. The genome presented here is only the fifth completed genome sequence of a member of the genus Deinococcus (and the forth type strain) to be published, and will hopefully contribute to a better understanding of how members of this genus adapted to high gamma- or UV ionizing-radiation. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 2,886,836 bp long genome with its four large plasmids of 97 kbp, 132 kbp, 196 kbp and 315 kbp harbours 2,741 protein-coding and 58 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  19. Complete genome sequence of the orange-red pigmented, radioresistant Deinococcus proteolyticus type strain (MRPT)

    PubMed Central

    Copeland, Alex; Zeytun, Ahmet; Yassawong, Montri; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Mavromatis, Konstantinos; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, Natalia; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Jeffries, Cynthia D.; Brambilla, Evelyne-Marie; Rohde, Manfred; Sikorski, Johannes; Pukall, Rüdiger; Göker, Markus; Detter, John C.; Woyke, Tanja; Bristow, James; Eisen, Jonathan A.; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C.; Klenk, Hans-Peter; Lapidus, Alla

    2012-01-01

    Deinococcus proteolyticus (ex Kobatake et al. 1973) Brook and Murray 1981 is one of currently 47 species in the genus Deinococcus within the family Deinococcaceae. Strain MRPT was isolated from feces of Lama glama and possesses extreme radiation resistance, a trait is shares with various other species of the genus Deinococcus, with D. proteolyticus being resistant up to 1.5 Mrad of gamma radiation. Strain MRPT is of further interest for its carotenoid pigment. The genome presented here is only the fifth completed genome sequence of a member of the genus Deinococcus (and the forth type strain) to be published, and will hopefully contribute to a better understanding of how members of this genus adapted to high gamma- or UV ionizing-radiation. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 2,886,836 bp long genome with its four large plasmids of lengths 97 kbp, 132 kbp, 196 kbp and 315 kbp harbors 2,741 protein-coding and 58 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project. PMID:22768367

  20. THE ASSEMBLY OF THE RED SEQUENCE AT z {approx} 1: THE COLOR AND SPECTRAL PROPERTIES OF GALAXIES IN THE Cl1604 SUPERCLUSTER

    SciTech Connect

    Lemaux, B. C.; Gal, R. R.; Lubin, L. M.; Fassnacht, C. D.; and others

    2012-02-01

    We investigate the properties of the 525 spectroscopically confirmed members of the Cl1604 supercluster at z {approx} 0.9 as part of the Observations of Redshift Evolution in Large Scale Environments survey. In particular, we focus on the photometric, stellar mass, morphological, and spectral properties of the 305 member galaxies of the eight clusters and groups that comprise the Cl1604 supercluster. Using an extensive Keck Low-Resolution Imaging Spectrometer (LRIS)/DEep Imaging Multi-Object Spectrograph (DEIMOS) spectroscopic database in conjunction with ten-band ground-based, Spitzer, and Hubble Space Telescope imaging, we investigate the buildup of the red sequence in groups and clusters at high redshift. Nearly all of the brightest and most massive red-sequence galaxies present in the supercluster environment are found to lie within the bounds of the cluster and group systems, with a surprisingly large number of such galaxies present in low-mass group systems. Despite the prevalence of these red-sequence galaxies, we find that the average cluster galaxy has a spectrum indicative of a star-forming galaxy, with a star formation rate between those of z {approx} 1 field galaxies and moderate-redshift cluster galaxies. The average group galaxy is even more active, exhibiting spectral properties indicative of a starburst. The presence of massive, red galaxies and the high fraction of starbursting galaxies present in the group environment suggest that significant processing is occurring in group environments at z {approx} 1 and earlier. There is a deficit of low-luminosity red-sequence galaxies in all Cl1604 clusters and groups, suggesting that such galaxies transition to the red sequence at later times. Extremely massive ({approx}10{sup 12} M{sub sun}) red-sequence galaxies routinely observed in rich clusters at z {approx} 0 are also absent from the Cl1604 clusters and groups. We suggest that such galaxies form at later times through merging processes. There are

  1. Transcriptomic analysis of the venom gland of the red-headed krait (Bungarus flaviceps) using expressed sequence tags

    PubMed Central

    2010-01-01

    Background The Red-headed krait (Bungarus flaviceps, Squamata: Serpentes: Elapidae) is a medically important venomous snake that inhabits South-East Asia. Although the venoms of most species of the snake genus Bungarus have been well characterized, a detailed compositional analysis of B. flaviceps is currently lacking. Results Here, we have sequenced 845 expressed sequence tags (ESTs) from the venom gland of a B. flaviceps. Of the transcripts, 74.8% were putative toxins; 20.6% were cellular; and 4.6% were unknown. The main venom protein families identified were three-finger toxins (3FTxs), Kunitz-type serine protease inhibitors (including chain B of β-bungarotoxin), phospholipase A2 (including chain A of β-bungarotoxin), natriuretic peptide (NP), CRISPs, and C-type lectin. Conclusion The 3FTxs were found to be the major component of the venom (39%). We found eight groups of unique 3FTxs and most of them were different from the well-characterized 3FTxs. We found three groups of Kunitz-type serine protease inhibitors (SPIs); one group was comparable to the classical SPIs and the other two groups to chain B of β-bungarotoxins (with or without the extra cysteine) based on sequence identity. The latter group may be functional equivalents of dendrotoxins in Bungarus venoms. The natriuretic peptide (NP) found is the first NP for any Asian elapid, and distantly related to Australian elapid NPs. Our study identifies several unique toxins in B. flaviceps venom, which may help in understanding the evolution of venom toxins and the pathophysiological symptoms induced after envenomation. PMID:20350308

  2. NIFTE: The Near Infrared Faint-Object Telescope Experiment

    NASA Technical Reports Server (NTRS)

    Bock, James J.; Lange, Andrew E.; Matsumoto, T.; Eisenhardt, Peter B.; Hacking, Perry B.; Schember, Helene R.

    1994-01-01

    The high sensitivity of large format InSb arrays can be used to obtain deep images of the sky at 3-5 micrometers. In this spectral range cool or highly redshifted objects (e.g. brown dwarfs and protogalaxies) which are not visible at shorter wavelengths may be observed. Sensitivity at these wavelengths in ground-based observations is severly limited by the thermal flux from the telescope and from the earth's atmosphere. The Near Infrared Faint-Object Telescope Experiment (NIFTE), a 50 cm cooled rocket-borne telescope combined with large format, high performance InSb arrays, can reach a limiting flux less than 1 micro-Jy(1-sigma) over a large field-of-view in a single flight. In comparison, the Infrared Space Observatory (ISO) will require days of observation to reach a sensitivity more than one order of magnitude worse over a similar area of the sky. The deep 3-5 micrometer images obtained by the rocket-borne telescope will assist in determining the nature of faint red objects detected by ground-based telescopes at 2 micrometers, and by ISO at wavelengths longer than 5 micrometers.

  3. Draft Genome Sequences of Two Thiomicrospira Strains Isolated from the Brine-Seawater Interface of Kebrit Deep in the Red Sea

    PubMed Central

    Zhang, Guishan; Fauzi Haroon, Mohamed; Zhang, Ruifu; Hikmawan, Tyas

    2016-01-01

    Two Thiomicrospira strains, WB1 and XS5, were isolated from the Kebrit Deep brine-seawater interface in the Red Sea, Saudi Arabia. Here, we present the draft genome sequences of these gammaproteobacteria, which both produce sulfuric acid from thiosulfate in culture. PMID:26966216

  4. Draft Genome Sequences of Two Thiomicrospira Strains Isolated from the Brine-Seawater Interface of Kebrit Deep in the Red Sea.

    PubMed

    Zhang, Guishan; Fauzi Haroon, Mohamed; Zhang, Ruifu; Hikmawan, Tyas; Stingl, Ulrich

    2016-01-01

    Two Thiomicrospira strains, WB1 and XS5, were isolated from the Kebrit Deep brine-seawater interface in the Red Sea, Saudi Arabia. Here, we present the draft genome sequences of these gammaproteobacteria, which both produce sulfuric acid from thiosulfate in culture. PMID:26966216

  5. Draft Genome Sequence of Pseudoalteromonas sp. Strain XI10 Isolated from the Brine-Seawater Interface of Erba Deep in the Red Sea

    PubMed Central

    Zhang, Guishan; Fauzi Haroon, Mohamed; Zhang, Ruifu; Hikmawan, Tyas

    2016-01-01

    Pseudoalteromonas sp. strain XI10 was isolated from the brine-seawater interface of Erba Deep in the Red Sea, Saudi Arabia. Here, we present the draft genome sequence of strain XI10, a gammaproteobacterium that synthesizes polysaccharides for biofilm formation when grown in liquid culture. PMID:26966209

  6. A Study of Planetary Nebulae using the Faint Object Infrared Camera for the SOFIA Telescope

    NASA Technical Reports Server (NTRS)

    Davis, Jessica

    2012-01-01

    A planetary nebula is formed following an intermediate-mass (1-8 solar M) star's evolution off of the main sequence; it undergoes a phase of mass loss whereby the stellar envelope is ejected and the core is converted into a white dwarf. Planetary nebulae often display complex morphologies such as waists or torii, rings, collimated jet-like outflows, and bipolar symmetry, but exactly how these features form is unclear. To study how the distribution of dust in the interstellar medium affects their morphology, we utilize the Faint Object InfraRed CAmera for the SOFIA Telescope (FORCAST) to obtain well-resolved images of four planetary nebulae--NGC 7027, NGC 6543, M2-9, and the Frosty Leo Nebula--at wavelengths where they radiate most of their energy. We retrieve mid infrared images at wavelengths ranging from 6.3 to 37.1 micron for each of our targets. IDL (Interactive Data Language) is used to perform basic analysis. We select M2-9 to investigate further; analyzing cross sections of the southern lobe reveals a slight limb brightening effect. Modeling the dust distribution within the lobes reveals that the thickness of the lobe walls is higher than anticipated, or rather than surrounding a vacuum surrounds a low density region of tenuous dust. Further analysis of this and other planetary nebulae is needed before drawing more specific conclusions.

  7. The complete mitochondrial genome sequence of Red knobby newt Tylototriton shanjing (Amphibia: Caudata).

    PubMed

    Jiang, Ye; Yang, Mingxian; Han, Fuyao; Li, Yan; Ni, Qingyong; Yao, Yongfang; Xu, Huailiang; Li, Ying; Zhang, Mingwang

    2016-07-01

    The complete mitogenome of Tylototriton shanjing is 16,661 bp in length with GenBank accession number KR154461, which contains 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), 2 ribosomal RNA genes (rRNA), and 1 control region (CR). The overall base composition of this mitogenome is biased toward AT content at 59.45%. Most of the PCGs and tRNA genes are located on the H-strand, except for ND6 subunit gene and eight tRNA genes, which were distributed on the L-strand. The PCGs used "ATG" and "GTG" as the start codons, while "TAA", "TAG", "AGA", and "T-" are used as stop codons. Almost all tRNA genes were folded into typical cloverleaf secondary structures. The T. shanjing genome had two tandem repeat sequences in the cob-noncoding region. The mitogenomic phylogenetic analyses shows that the genera Echinotriton and Tylototriton were clustered into a strong supported monophyletic clade, which is a sister clade to the genus Pleurodeles, this confirms the previous phylogenetic results. PMID:26065853

  8. Genetic characterization of red-colored heartwood genotypes of Chinese fir using simple sequence repeat (SSR) markers.

    PubMed

    Duan, H J; Hu, R Y; Wu, B; Chen, D X; Huang, K Y; Dai, J; Chen, Q; Wei, Z C; Cao, S; Sun, Y H; Li, Y

    2015-01-01

    The present study investigated the genetic characterization of red-colored heartwood Chinese fir [Cunninghamia lanceolata (Lamb.) Hook.] in Guangxi using 21 simple sequence repeat (SSR) markers and analyzes of the genetic variation (N = 149) in samples obtained from five sites in Guangxi Province, China. The number of different alleles and the Shannon's information index per locus ranged from 3 to 12 and from 0.398 to 2.258 with average values of 6 and 1.211, respectively, indicating moderate levels of genetic diversity within this germplasm collection. The observed and expected heterozygosity ranged from 0.199 to 0.827 and from 0.198 to 0.878 with an average of 0.562 and 0.584, respectively. Although, the mean fixation index was 0.044, indicative of a low level of genetic differentiation among germplasms, analysis of molecular variance revealed considerable differentiation (99%) within the samples. The neighbor-joining dendrogram revealed that the majority of red-colored Chinese fir genotypes were apparently not associated with their geographic origins. Further analysis by STRUCTURE showed that this Guangxi germplasm collection could be divided into three genetic groups comprising 76, 37, and 36 members, respectively; these were classified into mixed groups with no obvious population structure. These results were consistent with those of the cluster analysis. On the whole, our data provide a starting point for the management and conservation of the current Guangxi germplasm collection as well as for their efficient use in Chinese fir-breeding programs. PMID:26782503

  9. ASSEMBLY OF THE RED SEQUENCE IN INFRARED-SELECTED GALAXY CLUSTERS FROM THE IRAC SHALLOW CLUSTER SURVEY

    SciTech Connect

    Snyder, Gregory F.; Brodwin, Mark; Mancone, Conor M.; Gonzalez, Anthony H.; Zeimann, Gregory R.; Stanford, S. A.; Stern, Daniel; Eisenhardt, Peter R. M.; Brown, Michael J. I.; Dey, Arjun; Jannuzi, Buell; Perlmutter, Saul

    2012-09-10

    We present results for the assembly and star formation histories (SFHs) of massive ({approx}L*) red sequence galaxies (RSGs) in 11 spectroscopically confirmed, infrared-selected galaxy clusters at 1.0 < z < 1.5, the precursors to present-day massive clusters with M {approx} 10{sup 15} M{sub Sun }. Using rest-frame optical photometry, we investigate evolution in the color and scatter of the RSG population, comparing with models of possible SFHs. In contrast to studies of central cluster galaxies at lower redshift (z < 1), these data are clearly inconsistent with the continued evolution of stars formed and assembled primarily at a single, much earlier time. Specifically, we find that the colors of massive cluster galaxies at z Almost-Equal-To 1.5 imply that the bulk of star formation occurred at z {approx} 3, whereas by z Almost-Equal-To 1 their colors imply formation at z {approx} 2; therefore these galaxies exhibit approximately the same luminosity-weighted stellar age at 1 < z < 1.5. This likely reflects star formation that occurs over an extended period, the effects of significant progenitor bias, or both. Our results generally indicate that massive cluster galaxy populations began forming a significant mass of stars at z {approx}> 4, contained some red spheroids by z Almost-Equal-To 1.5, and were actively assembling much of their final mass during 1 < z < 2 in the form of younger stars. Qualitatively, the slopes of the cluster color-magnitude relations are consistent with no significant evolution relative to local clusters.

  10. Size growth of red-sequence early-type galaxies in clusters in the last 10 Gyr

    NASA Astrophysics Data System (ADS)

    Andreon, S.; Dong, Hui; Raichoor, A.

    2016-08-01

    We carried out a photometric and structural analysis in the rest-frame V band of a mass-selected (log M/M⊙> 10.7) sample of red-sequence galaxies in 14 galaxy clusters, 6 of which are at z> 1.45, namely JKCS041, IDCS J1426.5+3508, SpARCS104922.6+564032.5, SpARCSJ021524-034331, XDCPJ0044.0-2033, and SPT-CLJ2040-4451. To this end, we reduced/analyzed about 300 orbits of multicolor images taken with the Advanced Camera for Survey and the Wide Field Camera 3 on the Hubble Space Telescope. We uniformly morphologically classified galaxies from z = 0.023 to z = 1.803, and we homogeneously derived sizes (effective radii) for the entire sample. Furthermore, our size derivation allows, and therefore is not biased by, the presence of the usual variety of morphological structures seen in early-type galaxies, such as bulges, bars, disks, isophote twists, and ellipiticy gradients. By using such a mass-selected sample, composed of 244 red-sequence early-type galaxies, we find that the log of the galaxy size at a fixed stellar mass, log M/M⊙ = 11, has increased with time at a rate of 0.023 ± 0.002 dex per Gyr over the last 10 Gyr, in marked contrast with the threefold increase found in the literature for galaxies in the general field over the same period. This suggests, at face value, that secular processes should be excluded as the primary drivers of size evolution because we observed an environmental dependent size growth. Using spectroscopic ages of Coma early-type galaxies we also find that recently quenched early-type galaxies are a numerically minor population not different enough in size to alter the mean size at a given mass, which implies that the progenitor bias is minor, i.e., that the size evolution measured by selecting galaxies at the redshift of observation is indistinguishable from the one that compares ancestors and descendents. Full Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc

  11. Crowded Field Photometry in the CLASH Clusters: Measuring the Red Sequence of Cluster Galaxies with Robust Photometry

    NASA Astrophysics Data System (ADS)

    Connor, Thomas; Donahue, Megan; Moustakas, John; Kelson, Daniel; Coe, Dan A.; Postman, Marc; CLASH Team

    2016-01-01

    The Cluster Lensing And Supernova survey with Hubble (CLASH) is an HST multi-cycle treasury program investigating 25 massive clusters of galaxies with X-ray gas Tx > 5 keV, spanning ~5 to ~30 x 10^14 solar masses, and a redshift range of 0.15 < z < 0.9. With 500 orbits of HST time and 16-filter, ultraviolet to infrared photometry of each cluster, this survey offers an unprecedented dataset for cluster galaxy photometry across a span of age and mass, but obtaining robust photometry for the cluster members has been hampered by the crowded field. We have developed a new technique to detect and define objects despite the presence of overlapping light profiles and to measure photometry of galaxies overlapping the extended haloes of massive galaxies. Utilizing spectral energy distribution fitting, we infer the properties of the detected galaxies, including their abundances and the time since their first star formation. Here we will discuss our technique and results, including the role metallicity and age play in shaping the red sequence of cluster galaxies.

  12. Development and characterization of novel microsatellite markers by Next Generation Sequencing for the blue and red shrimp Aristeus antennatus

    PubMed Central

    Heras, Sandra; Planella, Laia; Caldarazzo, Ilaria; Vera, Manuel; García-Marín, José-Luis

    2016-01-01

    The blue and red shrimp, Aristeus antennatus, is a commercially important crustacean, in the Mediterranean Sea, which has been listed as a priority species for fishery management. Hypervariable microsatellite markers could be a useful tool to identify genetic stocks among geographically close fishing grounds. Potential microsatellite markers (97) identified from next-generation sequencing of an individual shrimp using a 454 GS Junior Pyrosequencer were tested on a preliminary panel of 15 individuals representing the four worldwide genetic stocks of the species from which 35 polymorphic loci were identified and used to characterize an additional 20 individuals from the Western Mediterranean Sea. In the Western Mediterranean sample, 32 out of 35 were polymorphic loci and the number of alleles per locus ranged from 2 to 14 and expected heterozygosity ranged from 0.050 to 0.968. No linkage disequilibrium was detected, indicating the independence of the loci. These novel microsatellites provide additional tools to address questions relating to genetic diversity, parentage studies and connectivity patterns of A. antennatus populations and help develop effective strategies to ensure long-term sustainability of this resource. PMID:27547526

  13. Inferring Invasion History of Red Swamp Crayfish (Procambarus clarkii) in China from Mitochondrial Control Region and Nuclear Intron Sequences

    PubMed Central

    Li, Yanhe; Guo, Xianwu; Chen, Liping; Bai, Xiaohui; Wei, Xinlan; Zhou, Xiaoyun; Huang, Songqian; Wang, Weimin

    2015-01-01

    Identifying the dispersal pathways of an invasive species is useful for adopting the appropriate strategies to prevent and control its spread. However, these processes are exceedingly complex. So, it is necessary to apply new technology and collect representative samples for analysis. This study used Approximate Bayesian Computation (ABC) in combination with traditional genetic tools to examine extensive sample data and historical records to infer the invasion history of the red swamp crayfish, Procambarus clarkii, in China. The sequences of the mitochondrial control region and the proPOx intron in the nuclear genome of samples from 37 sites (35 in China and one each in Japan and the USA) were analyzed. The results of combined scenarios testing and historical records revealed a much more complex invasion history in China than previously believed. P. clarkii was most likely originally introduced into China from Japan from an unsampled source, and the species then expanded its range primarily into the middle and lower reaches and, to a lesser extent, into the upper reaches of the Changjiang River in China. No transfer was observed from the upper reaches to the middle and lower reaches of the Changjiang River. Human-mediated jump dispersal was an important dispersal pathway for P. clarkii. The results provide a better understanding of the evolutionary scenarios involved in the rapid invasion of P. clarkii in China. PMID:26132567

  14. Development and characterization of novel microsatellite markers by Next Generation Sequencing for the blue and red shrimp Aristeus antennatus.

    PubMed

    Heras, Sandra; Planella, Laia; Caldarazzo, Ilaria; Vera, Manuel; García-Marín, José-Luis; Roldán, Maria Ines

    2016-01-01

    The blue and red shrimp, Aristeus antennatus, is a commercially important crustacean, in the Mediterranean Sea, which has been listed as a priority species for fishery management. Hypervariable microsatellite markers could be a useful tool to identify genetic stocks among geographically close fishing grounds. Potential microsatellite markers (97) identified from next-generation sequencing of an individual shrimp using a 454 GS Junior Pyrosequencer were tested on a preliminary panel of 15 individuals representing the four worldwide genetic stocks of the species from which 35 polymorphic loci were identified and used to characterize an additional 20 individuals from the Western Mediterranean Sea. In the Western Mediterranean sample, 32 out of 35 were polymorphic loci and the number of alleles per locus ranged from 2 to 14 and expected heterozygosity ranged from 0.050 to 0.968. No linkage disequilibrium was detected, indicating the independence of the loci. These novel microsatellites provide additional tools to address questions relating to genetic diversity, parentage studies and connectivity patterns of A. antennatus populations and help develop effective strategies to ensure long-term sustainability of this resource. PMID:27547526

  15. Faint detection of exoplanets in microlensing surveys

    SciTech Connect

    Brown, Robert A.

    2014-06-20

    We propose a new approach to discovering faint microlensing signals below traditional thresholds, and for estimating the binary-lens mass ratio and the apparent separation from such signals. The events found will be helpful in accurately estimating the true distribution of planetary semimajor axes, which is an important goal of space microlensing surveys.

  16. STELLAR POPULATIONS AND STRUCTURAL PROPERTIES OF ULTRA FAINT DWARF GALAXIES, CANES VENATICI I, BOOeTES I, CANES VENATICI II, AND LEO IV

    SciTech Connect

    Okamoto, Sakurako; Arimoto, Nobuo; Yamada, Yoshihiko; Onodera, Masato

    2012-01-10

    We take deep images of four ultra faint dwarf (UFD) galaxies, Canes Venatici I (CVn I), Booetes I (Booe I), Canes Venatici II (CVn II), and Leo IV, using the Suprime-Cam on the Subaru Telescope. Color-magnitude diagrams (CMDs) extend below main-sequence turnoffs (MSTOs) and yield measurements of the ages of stellar populations. The stellar populations of three faint galaxies, the Booe I, CVn II, and Leo IV dwarf spheroidal galaxies (dSphs), are estimated to be as old as the Galactic globular cluster M92. We confirm that Booe I dSph has no intrinsic color spread in the MSTO and no spatial difference in the CMD morphology, which indicates that Booe I dSph is composed of an old single stellar population. One of the brightest UFDs, CVn I dSph, shows a relatively younger age ({approx}12.6 Gyr) with respect to Booe I, CVn II, and Leo IV dSphs, and the distribution of red horizontal branch (HB) stars is more concentrated toward the center than that of blue HB stars, suggesting that the galaxy contains complex stellar populations. Booe I and CVn I dSphs show the elongated and distorted shapes. CVn II dSph has the smallest tidal radius of a Milky Way satellite and has a distorted shape, while Leo IV dSph shows a less concentrated spherical shape. The simple stellar population of faint UFDs indicates that the gases in their progenitors were removed more effectively than those of brighter dSphs at the occurrence of their initial star formation. This is reasonable if the progenitors of UFDs belong to less massive halos than those of brighter dSphs.

  17. Extreme Faint Flux Imaging with an EMCCD

    NASA Astrophysics Data System (ADS)

    Daigle, Olivier; Carignan, Claude; Gach, Jean-Luc; Guillaume, Christian; Lessard, Simon; Fortin, Charles-Anthony; Blais-Ouellette, Sébastien

    2009-08-01

    An EMCCD camera, designed from the ground up for extreme faint flux imaging, is presented. CCCP, the CCD Controller for Counting Photons, has been integrated with a CCD97 EMCCD from e2v technologies into a scientific camera at the Laboratoire d'Astrophysique Expérimentale (LAE), Université de Montréal. This new camera achieves subelectron readout noise and very low clock-induced charge (CIC) levels, which are mandatory for extreme faint flux imaging. It has been characterized in laboratory and used on the Observatoire du Mont Mégantic 1.6 m telescope. The performance of the camera is discussed and experimental data with the first scientific data are presented.

  18. Complete genome sequence of Coriobacterium glomerans type strain (PW2T) from the midgut of Pyrrhocoris apterus L. (red soldier bug)

    SciTech Connect

    Stackebrandt, Erko; Zeytun, Ahmet; Lapidus, Alla L.; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, N; Mavromatis, K; Mikhailova, Natalia; Huntemann, Marcel; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Chang, Yun-Juan; Land, Miriam L; Hauser, Loren John; Rohde, Manfred; Pukall, Rudiger; Goker, Markus; Detter, J. Chris; Woyke, Tanja; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter

    2013-01-01

    Coriobacterium glomerans Haas and Ko nig 1988, is the only species of the genus Coriobacterium, family Coriobacteriaceae, order Coriobacteriales, phylum Actinobacteria. The bacterium thrives as an endosymbiont of pyrrhocorid bugs, i.e. the red fire bug Pyrrhocoris apterus L. The rationale for sequencing the genome of strain PW2T is its endosymbiotic life style which is rare among members of Actinobacteria. Here we describe the features of this symbiont, together with the complete genome sequence and its annotation. This is the first complete genome sequence of a member of the genus Coriobacterium and the sixth member of the order Coriobacteriales for which complete genome sequences are now available. The 2,115,681 bp long single replicon genome with its 1,804 protein-coding and 54 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

  19. Spectrophotometry of faint comets: The asteroid approach

    NASA Technical Reports Server (NTRS)

    Degewij, J.

    1981-01-01

    Observing programs at optical (0.35-0.8 micron) and near-infrared (1.1-2.4 micron) wavelengths, directed at the acquisition of reflection spectra of faint and distant comets, are described. The ultimate goal is to obtain spectrophotometric measurements of comets for which a significant part of the light is expected to be reflected by the solid surface of the nucleus.

  20. Complete nucleotide sequence and organization of the mitogenome of the red-spotted apollo butterfly, Parnassius bremeri (Lepidoptera: Papilionidae) and comparison with other lepidopteran insects.

    PubMed

    Kim, Man Il; Baek, Jee Yeon; Kim, Min Jee; Jeong, Heon Cheon; Kim, Ki-Gyoung; Bae, Chang Hwan; Han, Yeon Soo; Jin, Byung Rae; Kim, Iksoo

    2009-10-31

    The 15,389-bp long complete mitogenome of the endangered red-spotted apollo butterfly, Parnassius bremeri (Lepidoptera: Papilionidae) was determined in this study. The start codon for the COI gene in insects has been extensively discussed, and has long remained a matter of some controversy. Herein, we propose that the CGA (arginine) sequence functions as the start codon for the COI gene in lepidopteran insects, on the basis of complete mitogenome sequences of lepidopteran insects, including P. bremeri, as well as additional sequences of the COI start region from a diverse taxonomic range of lepidopteran species (a total of 53 species from 15 families). In our extensive search for a tRNA-like structure in the A+T-rich region, one tRNA(Trp)-like sequence and one tRNA(Leu) (UUR)-like sequence were detected in the P. bremeri A+T-rich region, and one or more tRNA-like structures were detected in the A+T-rich region of the majority of other sequenced lepidopteran insects, thereby indicating that such features occur frequently in the lepidopteran mitogenomes. Phylogenetic analysis using the concatenated 13 amino acid sequences and nucleotide sequences of PCGs of the four macrolepidopteran superfamilies together with the Tortricoidea and Pyraloidea resulted in the successful recovery of a monophyly of Papilionoidea and a monophyly of Bombycoidea. However, the Geometroidea were unexpectedly identified as a sister group of the Bombycoidea, rather than the Papilionoidea. PMID:19823774

  1. Melanocortin 1 receptor (MC1R) gene sequence variation and melanism in the gray (Sciurus carolinensis), fox (Sciurus niger), and red (Sciurus vulgaris) squirrel.

    PubMed

    McRobie, Helen R; King, Linda M; Fanutti, Cristina; Coussons, Peter J; Moncrief, Nancy D; Thomas, Alison P M

    2014-01-01

    Sequence variations in the melanocortin 1 receptor (MC1R) gene are associated with melanism in many different species of mammals, birds, and reptiles. The gray squirrel (Sciurus carolinensis), found in the British Isles, was introduced from North America in the late 19th century. Melanism in the British gray squirrel is associated with a 24-bp deletion in the MC1R. To investigate the origin of this mutation, we sequenced the MC1R of 95 individuals including 44 melanic gray squirrels from both the British Isles and North America. Melanic gray squirrels of both populations had the same 24-bp deletion associated with melanism. Given the significant deletion associated with melanism in the gray squirrel, we sequenced the MC1R of both wild-type and melanic fox squirrels (Sciurus niger) (9 individuals) and red squirrels (Sciurus vulgaris) (39 individuals). Unlike the gray squirrel, no association between sequence variation in the MC1R and melanism was found in these 2 species. We conclude that the melanic gray squirrel found in the British Isles originated from one or more introductions of melanic gray squirrels from North America. We also conclude that variations in the MC1R are not associated with melanism in the fox and red squirrels. PMID:24534267

  2. Red, green, blue equals 1, 2, 3: Digit-color synesthetes can use structured digit information to boost recall of color sequences.

    PubMed

    Teichmann, A Lina; Nieuwenstein, Mark R; Rich, Anina N

    2015-01-01

    Digit-color synesthetes report experiencing colors when perceiving letters and digits. The conscious experience is typically unidirectional (e.g., digits elicit colors but not vice versa) but recent evidence shows subtle bidirectional effects. We examined whether short-term memory for colors could be affected by the order of presentation reflecting more or less structure in the associated digits. We presented a stream of colored squares and asked participants to report the colors in order. The colors matched each synesthete's colors for digits 1-9 and the order of the colors corresponded either to a sequence of numbers (e.g., [red, green, blue] if 1 = red, 2 = green, 3 = blue) or no systematic sequence. The results showed that synesthetes recalled sequential color sequences more accurately than pseudo-randomized colors, whereas no such effect was found for the non-synesthetic controls. Synesthetes did not differ from non-synesthetic controls in recall of color sequences overall, providing no evidence of a general advantage in memory for serial recall of colors. PMID:26114381

  3. The Population of Optically Faint GEO Debris

    NASA Technical Reports Server (NTRS)

    Seitzer, Patrick; Barker, Ed; Buckalew, Brent; Burkhardt, Andrew; Cowardin, Heather; Frith, James; Gomez, Juan; Kaleida, Catherine; Lederer, Susan M.; Lee, Chris H.

    2016-01-01

    The 6.5-m Magellan telescope 'Walter Baade' at the Las Campanas Observatory in Chile has been used for spot surveys of the GEO orbital regime to study the population of optically faint GEO debris. The goal is to estimate the size of the population of GEO debris at sizes much smaller than can be studied with 1-meter class telescopes. Despite the small size of the field of view of the Magellan instrument (diameter 0.5-degree), a significant population of objects fainter than R = 19th magnitude have been found with angular rates consistent with circular orbits at GEO. We compare the size of this population with the numbers of GEO objects found at brighter magnitudes by smaller telescopes. The observed detections have a wide range in characteristics starting with those appearing as short uniform streaks. But there are a substantial number of detections with variations in brightness, flashers, during the 5-second exposure. The duration of each of these flashes can be extremely brief: sometimes less than half a second. This is characteristic of a rapidly tumbling object with a quite variable projected size times albedo. If the albedo is of the order of 0.2, then the largest projected size of these objects is around 10-cm. The data in this paper was collected over the last several years using Magellan's IMACS camera in f/2 mode. The analysis shows the brightness bins for the observed GEO population as well as the periodicity of the flashers. All objects presented are correlated with the catalog: the focus of the paper will be on the uncorrelated, optically faint, objects. The goal of this project is to better characterize the faint debris population in GEO that access to a 6.5-m optical telescope in a superb site can provide.

  4. Spectroscopic surveys of faint blue stars

    NASA Technical Reports Server (NTRS)

    Wegner, Gary; Boley, Forrest I.; Swanson, Steven R.; Mcmahan, Robert K.

    1987-01-01

    Spectroscopy of 450 faint blue stars obtained with the spectrograph and intensified Reticon scanner on the 1.3 m telescope at the McGraw Hill Observatory located at Kitt Peak are examined. The study is limited to objects brighter than V = 17.0 in magnitude. It is found that the relative numbers of objects such as white dwarfs, QSOs and CVs in the Kisco survey (Noguchi et al. 1980) is similar to that in the survey of Green et al., (1986).

  5. The formation of Jupiter's faint rings

    PubMed

    Burns; Showalter; Hamilton; Nicholson; de Pater I; Ockert-Bell; Thomas

    1999-05-14

    Observations by the Galileo spacecraft and the Keck telescope showed that Jupiter's outermost (gossamer) ring is actually two rings circumscribed by the orbits of the small satellites Amalthea and Thebe. The gossamer rings' unique morphology-especially the rectangular end profiles at the satellite's orbit and the enhanced intensities along the top and bottom edges of the rings-can be explained by collisional ejecta lost from the inclined satellites. The ejecta evolves inward under Poynting-Robertson drag. This mechanism may also explain the origin of Jupiter's main ring and suggests that faint rings may accompany all small inner satellites of the other jovian planets. PMID:10325220

  6. Expressed sequence tags from the red imported fire ant, Solenopsis invicta: Annotation and utilization for discovery of viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An expression library was created and 2,300 clones sequenced from a monogyne colony of Solenopsis invicta with the primary intention of discovering viruses infecting this ant pest. After assembly and removal of mitochondrial and poor quality sequences, 1,054 unique sequences were yielded and deposi...

  7. Galaxy population properties of the massive X-ray luminous galaxy cluster XDCP J0044.0-2033 at z = 1.58. Red-sequence formation, massive galaxy assembly, and central star formation activity

    NASA Astrophysics Data System (ADS)

    Fassbender, R.; Nastasi, A.; Santos, J. S.; Lidman, C.; Verdugo, M.; Koyama, Y.; Rosati, P.; Pierini, D.; Padilla, N.; Romeo, A. D.; Menci, N.; Bongiorno, A.; Castellano, M.; Cerulo, P.; Fontana, A.; Galametz, A.; Grazian, A.; Lamastra, A.; Pentericci, L.; Sommariva, V.; Strazzullo, V.; Šuhada, R.; Tozzi, P.

    2014-08-01

    cluster-core population comprises post-quenched galaxies transitioning toward the red sequence at intermediate magnitudes, while additionally a significant blue-cloud population of faint star-forming galaxies is present even in the densest central regions. Based on a color-color selection performed to separate different cluster galaxy types, we find that the blue star-forming population is concentrated in clumpy structures and dominates in particular at and beyond the R500 radius. On the other hand, the fraction of post-starburst galaxies steadily increases toward the center, while the red-locus population and red-sequence transition galaxies seem to reach their peak fractions already at intermediate cluster-centric radii of about r ~ 200 kpc. Conclusions: Our observations support the scenario in which the dominant effect of the dense z ≃ 1.6 cluster environment is an accelerated mass-assembly timescale (~1 Gyr or shorter) through merging activity that is responsible for driving core galaxies across the mass-quenching threshold of log (M∗/M⊙) ≃ 10.4. Beyond this mass limit, star formation is suppressed on timescales of ~1 Gyr, while the direct environmental quenching process seems to be subdominant and is acting on significantly longer timescales (~2-3 Gyr). Based on observations under programme ID 084.A-0844, 087.A-0351, and 089.A-0419 collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile.J- and Ks-band FITS files are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/568/A5

  8. Microbial Diversity of the Brine-Seawater Interface of the Kebrit Deep, Red Sea, Studied via 16S rRNA Gene Sequences and Cultivation Methods

    PubMed Central

    Eder, Wolfgang; Jahnke, Linda L.; Schmidt, Mark; Huber, Robert

    2001-01-01

    The brine-seawater interface of the Kebrit Deep, northern Red Sea, was investigated for the presence of microorganisms using phylogenetic analysis combined with cultivation methods. Under strictly anaerobic culture conditions, novel halophiles were isolated. The new rod-shaped isolates belong to the halophilic genus Halanaerobium and are the first representatives of the genus obtained from deep-sea, anaerobic brine pools. Within the genus Halanaerobium, they represent new species which grow chemoorganotrophically at NaCl concentrations ranging from 5 to 34%. The cellular fatty acid compositions are consistent with those of other Halanaerobium representatives, showing unusually large amounts of Δ7 and Δ11 16:1 fatty acids. Phylogenetic analysis of the brine-seawater interface sample revealed the presence of various bacterial 16S rRNA gene sequences dominated by cultivated members of the bacterial domain, with the majority affiliated with the genus Halanaerobium. The new Halanaerobium 16S rRNA clone sequences showed the highest similarity (99.9%) to the sequence of isolate KT-8-13 from the Kebrit Deep brine. In this initial survey, our polyphasic approach demonstrates that novel halophiles thrive in the anaerobic, deep-sea brine pool of the Kebrit Deep, Red Sea. They may contribute significantly to the anaerobic degradation of organic matter enriched at the brine-seawater interface. PMID:11425725

  9. PMAS - Faint Object 3D Spectrophotometry

    NASA Astrophysics Data System (ADS)

    Roth, M. M.; Becker, T.; Kelz, A.

    2002-01-01

    will describe PMAS (Potsdam Multiaperture Spectrophotometer) which was commissioned at the Calar Alto Observatory 3.5m Telescope on May 28-31, 2001. PMAS is a dedicated, highly efficient UV-visual integral field spectrograph which is optimized for the spectrophotometry of faint point sources, typically superimposed on a bright background. PMAS is ideally suited for the study of resolved stars in local group galaxies. I will present results of our preliminary work with MPFS at the Russian 6m Telescope in Selentchuk, involving the development of new 3D data reduction software, and observations of faint planetary nebulae in the bulge of M31 for the determination of individual chemical abundances of these objects. Using this data, it will be demonstrated that integral field spectroscopy provides superior techniques for background subtraction, avoiding the otherwise inevitable systematic errors of conventional slit spetroscopy. The results will be put in perspective of the study of resolved stellar populations in nearby galaxies with a new generation of Extremely Large Telescopes.

  10. Cold H I in faint dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Patra, Narendra Nath; Chengalur, Jayaram N.; Karachentsev, Igor D.; Kaisin, Serafim S.; Begum, Ayesha

    2016-03-01

    We present the results of a study of the amount and distribution of cold atomic gas, as well its correlation with recent star formation in a sample of extremely faint dwarf irregular galaxies. Our sample is drawn from the Faint Irregular Galaxy GMRT Survey (FIGGS) and its extension, FIGGS2. We use two different methods to identify cold atomic gas. In the first method, line-of-sight H I spectra were decomposed into multiple Gaussian components and narrow Gaussian components were identified as cold H I. In the second method, the brightness temperature (TB ) is used as a tracer of cold H I. We find that the amount of cold gas identified using the TB method is significantly larger than the amount of gas identified using Gaussian decomposition. We also find that a large fraction of the cold gas identified using the TB method is spatially coincident with regions of recent star formation, although the converse is not true. That is only a small fraction of the regions with recent star formation are also covered by cold gas. For regions where the star formation and the cold gas overlap, we study the relationship between the star formation rate density and the cold H I column density. We find that the star formation rate density has a power-law dependence on the H I column density, but that the slope of this power law is significantly flatter than that of the canonical Kennicutt-Schmidt relation.

  11. Controversial age spreads from the main sequence turn-off and red clump in intermediate-age clusters in the LMC

    NASA Astrophysics Data System (ADS)

    Niederhofer, F.; Bastian, N.; Kozhurina-Platais, V.; Hilker, M.; de Mink, S. E.; Cabrera-Ziri, I.; Li, C.; Ercolano, B.

    2016-02-01

    Most star clusters at an intermediate age (1-2 Gyr) in the Large and Small Magellanic Clouds show a puzzling feature in their color-magnitude diagrams (CMD) that is not in agreement with a simple stellar population. The main sequence turn-off of these clusters is much broader than expected from photometric uncertainties. One interpretation of this feature is that age spreads of the order of 200-500 Myr exist within individual clusters, although this interpretation is highly debated. Such large age spreads should affect other parts of the CMD, which are sensitive to age, as well. In this study, we analyze the CMDs of a sample of 12 intermediate-age clusters in the Large Magellanic Cloud that all show an extended turn-off using archival optical data taken with the Hubble Space Telescope. We fit the star formation history of the turn-off region and the red clump region independently. We find that in most cases, the age spreads inferred from the red clumps are smaller than those that result from the turn-off region. However, the age ranges that result from the red clump region are broader than expected for a single age. Only two out of 12 clusters in our sample show a red clump which seems to be consistent with a single age. As our results are ambiguous, by fitting the star formation histories to the red clump regions, we cannot ultimately tell if the extended main sequence turn-off feature is the result of an age spread or not. However, we do find that the width of the extended main sequence turn-off feature is correlated with the age of the clusters in a way which would be unexplained in the so-called age spread interpretation, but which may be expected if stellar rotation is the cause of the spread at the turn-off. Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST

  12. Spectroscopic Confirmation of a Massive Red-sequence Selected Galaxy Cluster at Z=1.34 in the SpARCS-South Cluster Survey

    NASA Technical Reports Server (NTRS)

    Wilson, Gillian; Demarco, Ricardo; Muzzin, Adam; Yee, H.K.C.; Lacy, Mark; Surace, Jason; Gilbank, David; Blindert, Kris; Hoekstra, Henk; Majumdar, Subhabrata; Gardner, Jonathan P; Gladders, Michael D.; Lonsdale, Carol

    2008-01-01

    The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a z'-passband imaging survey, consisting of deep (z' approx. 24 AB) observations made from both hemispheres using the CFHT 3.6m and CTIO 4m telescopes. The survey was designed with the primary aim of detecting galaxy clusters at z > 1. In tandem with pre-existing 3.6 micron observations from the Spitzer Space Telescope SWIRE Legacy Survey, SpARCS detects clusters using an infrared adaptation of the two-filter red-sequence cluster technique. The total effective area of the SpARCS cluster survey is 41.9 sq deg. In this paper, we provide an overview of the 13.6 sq deg Southern CTIO/MOSAICII observations. The 28.3 sq deg Northern CFHT/MegaCam observations are summarized in a companion paper by Muzzin et al. (2008a). In this paper, we also report spectroscopic confirmation of SpARCS J003550-431224, a very rich galaxy cluster at z = 1.335, discovered in the ELAIS-S1 field. To date, this is the highest spectroscopically confirmed redshift for a galaxy cluster discovered using the red-sequence technique. Based on nine confirmed members, SpARCS J003550-431224 has a preliminary velocity dispersion of 1050+/-230 km/s. With its proven capability for efficient cluster detection, SpARCS is a demonstration that we have entered an era of large, homogeneously-selected z > 1 cluster surveys.

  13. De Novo Transcriptome Sequencing Analysis of cDNA Library and Large-Scale Unigene Assembly in Japanese Red Pine (Pinus densiflora)

    PubMed Central

    Liu, Le; Zhang, Shijie; Lian, Chunlan

    2015-01-01

    Japanese red pine (Pinus densiflora) is extensively cultivated in Japan, Korea, China, and Russia and is harvested for timber, pulpwood, garden, and paper markets. However, genetic information and molecular markers were very scarce for this species. In this study, over 51 million sequencing clean reads from P. densiflora mRNA were produced using Illumina paired-end sequencing technology. It yielded 83,913 unigenes with a mean length of 751 bp, of which 54,530 (64.98%) unigenes showed similarity to sequences in the NCBI database. Among which the best matches in the NCBI Nr database were Picea sitchensis (41.60%), Amborella trichopoda (9.83%), and Pinus taeda (4.15%). A total of 1953 putative microsatellites were identified in 1784 unigenes using MISA (MicroSAtellite) software, of which the tri-nucleotide repeats were most abundant (50.18%) and 629 EST-SSR (expressed sequence tag- simple sequence repeats) primer pairs were successfully designed. Among 20 EST-SSR primer pairs randomly chosen, 17 markers yielded amplification products of the expected size in P. densiflora. Our results will provide a valuable resource for gene-function analysis, germplasm identification, molecular marker-assisted breeding and resistance-related gene(s) mapping for pine for P. densiflora. PMID:26690126

  14. De Novo Transcriptome Sequencing Analysis of cDNA Library and Large-Scale Unigene Assembly in Japanese Red Pine (Pinus densiflora).

    PubMed

    Liu, Le; Zhang, Shijie; Lian, Chunlan

    2015-01-01

    Japanese red pine (Pinus densiflora) is extensively cultivated in Japan, Korea, China, and Russia and is harvested for timber, pulpwood, garden, and paper markets. However, genetic information and molecular markers were very scarce for this species. In this study, over 51 million sequencing clean reads from P. densiflora mRNA were produced using Illumina paired-end sequencing technology. It yielded 83,913 unigenes with a mean length of 751 bp, of which 54,530 (64.98%) unigenes showed similarity to sequences in the NCBI database. Among which the best matches in the NCBI Nr database were Picea sitchensis (41.60%), Amborella trichopoda (9.83%), and Pinus taeda (4.15%). A total of 1953 putative microsatellites were identified in 1784 unigenes using MISA (MicroSAtellite) software, of which the tri-nucleotide repeats were most abundant (50.18%) and 629 EST-SSR (expressed sequence tag- simple sequence repeats) primer pairs were successfully designed. Among 20 EST-SSR primer pairs randomly chosen, 17 markers yielded amplification products of the expected size in P. densiflora. Our results will provide a valuable resource for gene-function analysis, germplasm identification, molecular marker-assisted breeding and resistance-related gene(s) mapping for pine for P. densiflora. PMID:26690126

  15. Sarcocystis species in red deer revisited: with a re-description of two known species as Sarcocystis elongata n. sp. and Sarcocystis truncata n. sp. based on mitochondrial cox1 sequences.

    PubMed

    Gjerde, Bjørn

    2014-03-01

    In a previous investigation, five Sarcocystis species were described from Norwegian red deer and believed to be conspecific with species occurring in either reindeer or moose based on sarcocyst morphology and nucleotide sequences of the nuclear ribosomal DNA unit. The aim of the present study was to characterize numerous isolates of these sarcocyst types at the mitochondrial cytochrome c oxidase subunit I gene (cox1) in order to corroborate or refute previous species designations of Sarcocystis in red deer. The Sarcocystis tarandi- and Sarcocystis rangiferi-like taxa in red deer and reindeer, respectively, were thoroughly compared by sequencing 14-27 isolates of each type. Sequence comparisons revealed four distinct sequence types, which by phylogenetic analyses were placed in four monophyletic groups according to host origin, and they were therefore considered to represent four separate species. The two taxa of this type in red deer were named Sarcocystis elongata and Sarcocystis truncata, respectively. Sequencing of many isolates of Sarcocystis hjorti and Sarcocystis ovalis from red deer and moose confirmed that these species occur in both hosts. A revised description of the two new species is given and the current knowledge concerning all six Sarcocystis species in red deer is reviewed. PMID:24230915

  16. A Search For Optically Faint GEO Debris

    NASA Astrophysics Data System (ADS)

    Seitzer, P.; Lederer, S.; Barker, E.; Cowardin, H.; Abercromby, K.; Silha, J.; Burkhardt, A.

    2011-09-01

    Existing optical surveys for debris at geosynchronous orbit (GEO) have been conducted with meter class telescopes, which have detection limits in the range of 18th-19th magnitude. We report on a new search for optically faint debris at GEO using the 6.5-m Magellan telescope ‘Walter Baade’ at Las Campanas Observatory in Chile. Our goal is to go as faint as possible and characterize the brightness distribution of debris fainter than R = 20th magnitude, corresponding to a size smaller than 10 cm assuming an albedo of 0.175. We wish to compare the inferred size distribution for GEO debris with that for LEO debris. We describe preliminary results obtained during 9.4 hours of observing time during 25-27 March 2011. We used the IMACS f/2 instrument, which has a mosaic of 8 CCDs, and a field of view of 30 arc-minutes in diameter. This is the widest field of view of any instrument on either Magellan telescope. All observations were obtained through a Sloan r’ filter. The limiting magnitude for 5 second exposures is measured to be fainter tan R = 21. With this small field of view and the limited observing time, our objective was to search for optically faint objects from the Titan 3C Transtage (1968-081) fragmentation in 1992. Eight debris pieces and the parent rocket body are in the Space Surveillance Network public catalog. We successfully tracked two cataloged pieces of Titan debris (SSN # 25001 and 33519) with the 6.5-m telescope, followed by a survey for objects on similar orbits but with a spread in mean anomaly. To detect bright objects over a wider field of view (1.6x1.6 degrees), we observed the same field centers at the same time through a similar filter with the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope), located 100 km to the south of Magellan at Cerro Tololo Inter-American Observatory, Chile. We will describe our experiences using Magellan, a telescope never used previously for orbital debris research, and our initial results.

  17. A Search for Optically Faint GEO Debris

    NASA Technical Reports Server (NTRS)

    Seitzer, Patrick; Lederer, Susan M.; Barker, Edwin S.; Cowardin, Heather; Abercromby, Kira J.; ilha, Jiri

    2011-01-01

    Existing optical surveys for debris at geosynchronous orbit (GEO) have been conducted with meter class telescopes, which have detection limits in the range of 18th-19th magnitude. We report on a new search for optically faint debris at GEO using the 6.5-m Magellan 1 telescope Walter Baade at Las Campanas Observatory in Chile. Our goal is to go as faint as possible and characterize the brightness distribution of debris fainter than R = 20th magnitude, corresponding to a size smaller than 10 cm assuming an albedo of 0.175. We wish to compare the inferred size distribution for GEO debris with that for LEO debris. We describe results obtained during 9.4 hours of observing time during 25-27 March 2011. We used the IMACS f/2 instrument, which has a mosaic of 8 CCDs, and a field of view of 30 arc-minutes in diameter. This is the widest field of view of any instrument on either Magellan telescope. All observations were obtained through a Sloan r filter. The limiting magnitude for 5 second exposures is estimated to be fainter than 22. With this small field of view and the limited observing time, our objective was to search for optically faint objects from the Titan 3C Transtage (1968-081) fragmentation in 1992. Eight debris pieces and the parent rocket body are in the Space Surveillance Network public catalog. We successfully tracked two cataloged pieces of Titan debris (SSN # 25001 and 33519) with the 6.5-m telescope, followed by a survey for objects on similar orbits but with a spread in mean anomaly. To detect bright objects over a wider field of view (1.6x1.6 degrees), we observed the same field centers at the same time through a similar filter with the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope), located 100 km to the south of Magellan at Cerro Tololo Inter-American Observatory, Chile. We will describe our experiences using Magellan, a telescope never used previously for orbital debris research, and our initial results.

  18. A unique charged tyrosine-containing member of the adipokinetic hormone/red-pigment-concentrating hormone peptide family isolated and sequenced from two beetle species.

    PubMed

    Gäde, G

    1991-05-01

    An identical neuropeptide was isolated from the corpora cardiaca of two beetle species, Melolontha melolontha and Geotrupes stercorosus. Its primary structure was determined by pulsed-liquid-phase sequencing employing Edman chemistry after enzymically deblocking the N-terminal pyroglutamate residue. The C-terminus was also blocked, as indicated by the lack of digestion when the peptide was incubated with carboxypeptidase A. The sequence of this peptide, which is designated Mem-CC, is pGlu-Leu-Asn-Tyr-Ser-Pro-Asp-Trp-NH2. It is a new member of the adipokinetic hormone/red-pigment-concentrating hormone (AKH/RPCH) family of peptides with two unusual structural features: it is charged and contains a tyrosine residue at position 4, where all other family members have a phenylalanine residue. Structure-activity studies in the migratory locust (Locusta migratoria) and the American cockroach (Periplaneta americana) revealed that the peptide was poorly active, owing to its structural uniqueness. PMID:2039445

  19. Revealing a comet-like shape of the faint periphery of the nearby galaxy M 32

    NASA Astrophysics Data System (ADS)

    Georgiev, Ts. B.

    2016-02-01

    We performed BVRI photometry of the galaxy M 32 building images and isophote maps in magnitudes and in color indexes. While searching for the faint thick disk of M 32 we apply median filtering with aperture of 7.3 arcmin to detach the residual image of M 32 and its periphery above the surrounding magnitude or color background. The residual images in all photometric systems show that the periphery of M 32 possesses a comet-like shape with a tail oriented to SSE, in a direction opposite to the direction of M 110. The images calibrated in color indexes (b - v) and (b - v)+(r - i) show that the tail is redder than the local median background. The residual images in color indexes show that the red tail broadens and curves in direction towards S and SW. Simultaneously, the brightest part of M 32 occurs bounded from NW-NE-SE sides by a sickle-like formation with a significantly lower red color index. Generally, we do not find a faint thick disk of M 32. However, the comet-like shape on the periphery of M 32, especially as a formation with an increased red color index, provokes involuntarily the impression that the satellite M 32 overtakes the Andromeda galaxy. The redshifts show that the intimacy velocity of M 32 and Andromeda galaxy is about 100 km/s.

  20. Faint object 3D spectroscopy with PMAS

    NASA Astrophysics Data System (ADS)

    Roth, Martin M.; Becker, Thomas; Kelz, Andreas; Bohm, Petra

    2004-09-01

    PMAS is a fiber-coupled lens array type of integral field spectrograph, which was commissioned at the Calar Alto 3.5m Telescope in May 2001. The optical layout of the instrument was chosen such as to provide a large wavelength coverage, and good transmission from 0.35 to 1 μm. One of the major objectives of the PMAS development has been to perform 3D spectrophotometry, taking advantage of the contiguous array of spatial elements over the 2-dimensional field-of-view of the integral field unit. With science results obtained during the first two years of operation, we illustrate that 3D spectroscopy is an ideal tool for faint object spectrophotometry.

  1. Orbital objects detection algorithm using faint streaks

    NASA Astrophysics Data System (ADS)

    Tagawa, Makoto; Yanagisawa, Toshifumi; Kurosaki, Hirohisa; Oda, Hiroshi; Hanada, Toshiya

    2016-02-01

    This study proposes an algorithm to detect orbital objects that are small or moving at high apparent velocities from optical images by utilizing their faint streaks. In the conventional object-detection algorithm, a high signal-to-noise-ratio (e.g., 3 or more) is required, whereas in our proposed algorithm, the signals are summed along the streak direction to improve object-detection sensitivity. Lower signal-to-noise ratio objects were detected by applying the algorithm to a time series of images. The algorithm comprises the following steps: (1) image skewing, (2) image compression along the vertical axis, (3) detection and determination of streak position, (4) searching for object candidates using the time-series streak-position data, and (5) selecting the candidate with the best linearity and reliability. Our algorithm's ability to detect streaks with signals weaker than the background noise was confirmed using images from the Australia Remote Observatory.

  2. Observing Faint Companions Close to Bright Stars

    NASA Astrophysics Data System (ADS)

    Serabyn, Eugene

    2012-04-01

    Progress in a number of technical areas is enabling imaging and interferometric observations at both smaller angular separations from bright stars and at deeper relative contrast levels. Here we discuss recent progress in several ongoing projects at the Jet Propulsion Laboratory. First, extreme adaptive optics wavefront correction has recently enabled the use of very short (i.e., blue) wavelengths to resolve close binaries. Second, phase-based coronagraphy has recently allowed observations of faint companions to within nearly one diffraction beam width of bright stars. Finally, rotating interferometers that can observe inside the diffraction beam of single aperture telescopes are being developed to detect close-in companions and bright exozodiacal dust. This paper presents a very brief summary of the techniques involved, along with some illustrative results.

  3. Searching for Optically Faint GEO Debris

    NASA Technical Reports Server (NTRS)

    Seitzer, Patrick; Lederer, Susan M.; Abercromby, Kira J.; Barker, Edwin S.; Burkhardt, Andrew; Cowardin, Heather; Krisko, Paula; Silha, Jiri

    2012-01-01

    We report on results from a search for optically faint debris (defined as R > 20th magnitude, or smaller than 10 cm assuming an albedo of 0.175)) at geosynchronous orbit (GEO) using the 6.5-m Magellan telescope "Walter Baade" at Las Campanas Observatory in Chile. Our goal is to characterize the brightness distribution of debris to the faintest limiting magnitude possible. Our data was obtained during 6 hours of observing time during the photometric nights of 26 and 27 March 2011 with the IMACS f/2 instrument, which has a field of view (fov) of 0.5 degrees in diameter. All observations were obtained through a Sloan r filter, and calibrated by observations of Landolt standard stars. Our primary objective was to search for optically faint objects from one of the few known fragmentations at GEO: the Titan 3C Transtage (1968-081) fragmentation in 1992. Eight debris pieces and the parent rocket body are in the Space Surveillance Network public catalog. We successfully tracked two cataloged pieces of Titan debris with the 6.5-m telescope, followed by a survey for unknown objects on similar orbits but with different mean anomalies. To establish the bright end of the debris population, calibrated observations were acquired on the same field centers, telescope rates, and time period with a similar filter on the 0.6-m MODEST (Michigan Orbital DEbris Survey Telescope), located 100 km to the south of Magellan at Cerro Tololo Inter-American Observatory, Chile. We will show the calibrated brightness distributions from both telescopes, and compare the observed brightness distributions with that predicted for various population models of debris of different sizes.

  4. First Results from the ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Wolstencroft, R. D.; Wehrle, A. E.; Levine, D. A.

    1997-01-01

    We present the first result from the ISO-IRAS Faint Galaxy Survey (IIFGS), a program designed to obtain ISO observations of the most distant and luminous galaxies in the IRAS Faint Source Survey by filling short gaps in the ISO observing schedule with pairs of 12um ISOCAM AND 90um ISOPHOT observation.

  5. MEASURING THE UNDETECTABLE: PROPER MOTIONS AND PARALLAXES OF VERY FAINT SOURCES

    SciTech Connect

    Lang, Dustin; Hogg, David W.; Jester, Sebastian; Rix, Hans-Walter

    2009-05-15

    The near future of astrophysics involves many large solid-angle, multi-epoch, multiband imaging surveys. These surveys will, at their faint limits, have data on a large number of sources that are too faint to be detected at any individual epoch. Here, we show that it is possible to measure in multi-epoch data not only the fluxes and positions, but also the parallaxes and proper motions of sources that are too faint to be detected at any individual epoch. The method involves fitting a model of a moving point source simultaneously to all imaging, taking account of the noise and point-spread function (PSF) in each image. By this method it is possible to measure the proper motion of a point source with an uncertainty close to the minimum possible uncertainty given the information in the data, which is limited by the PSF, the distribution of observation times (epochs), and the total signal-to-noise in the combined data. We demonstrate our technique on multi-epoch Sloan Digital Sky Survey (SDSS) imaging of the SDSS Southern Stripe (SDSSSS). We show that with our new technique we can use proper motions to distinguish very red brown dwarfs from very high-redshift quasars in these SDSS data, for objects that are inaccessible to traditional techniques, and with better fidelity than by multiband imaging alone. We rediscover all 10 known brown dwarfs in our sample and present nine new candidate brown dwarfs, identified on the basis of significant proper motion.

  6. A Peculiar Faint Satellite in the Remote Outer Halo of M31

    NASA Astrophysics Data System (ADS)

    Mackey, A. D.; Huxor, A. P.; Martin, N. F.; Ferguson, A. M. N.; Dotter, A.; McConnachie, A. W.; Ibata, R. A.; Irwin, M. J.; Lewis, G. F.; Sakari, C. M.; Tanvir, N. R.; Venn, K. A.

    2013-06-01

    We present Hubble Space Telescope imaging of a newly discovered faint stellar system, PAndAS-48, in the outskirts of the M31 halo. Our photometry reveals this object to be comprised of an ancient and very metal-poor stellar population with age >~ 10 Gyr and [Fe/H] lsim -2.3. Our inferred distance modulus (m - M)0 = 24.57 ± 0.11 confirms that PAndAS-48 is most likely a remote M31 satellite with a three-dimensional galactocentric radius of 149^{+19}_{-8} kpc. We observe an apparent spread in color on the upper red giant branch that is larger than the photometric uncertainties should allow, and briefly explore the implications of this. Structurally, PAndAS-48 is diffuse, faint, and moderately flattened, with a half-light radius r_h=26^{+4}_{-3} pc, integrated luminosity MV = -4.8 ± 0.5, and ellipticity \\epsilon =0.30^{+0.08}_{-0.15}. On the size-luminosity plane it falls between the extended globular clusters seen in several nearby galaxies and the recently discovered faint dwarf satellites of the Milky Way; however, its characteristics do not allow us to unambiguously classify it as either type of system. If PAndAS-48 is a globular cluster then it is among the most elliptical, isolated, and metal-poor of any seen in the Local Group, extended or otherwise. Conversely, while its properties are generally consistent with those observed for the faint Milky Way dwarfs, it would be a factor of ~2-3 smaller in spatial extent than any known counterpart of comparable luminosity. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program GO 12515.

  7. A PECULIAR FAINT SATELLITE IN THE REMOTE OUTER HALO OF M31

    SciTech Connect

    Mackey, A. D.; Dotter, A.; Huxor, A. P.; Martin, N. F.; Ibata, R. A.; Ferguson, A. M. N.; McConnachie, A. W.; Irwin, M. J.; Lewis, G. F.; Sakari, C. M.; Venn, K. A.; Tanvir, N. R.

    2013-06-20

    We present Hubble Space Telescope imaging of a newly discovered faint stellar system, PAndAS-48, in the outskirts of the M31 halo. Our photometry reveals this object to be comprised of an ancient and very metal-poor stellar population with age {approx}> 10 Gyr and [Fe/H] {approx}< -2.3. Our inferred distance modulus (m - M){sub 0} = 24.57 {+-} 0.11 confirms that PAndAS-48 is most likely a remote M31 satellite with a three-dimensional galactocentric radius of 149{sup +19}{sub -8} kpc. We observe an apparent spread in color on the upper red giant branch that is larger than the photometric uncertainties should allow, and briefly explore the implications of this. Structurally, PAndAS-48 is diffuse, faint, and moderately flattened, with a half-light radius r{sub h}=26{sup +4}{sub -3} pc, integrated luminosity M{sub V} = -4.8 {+-} 0.5, and ellipticity {epsilon}=0.30{sup +0.08}{sub -0.15}. On the size-luminosity plane it falls between the extended globular clusters seen in several nearby galaxies and the recently discovered faint dwarf satellites of the Milky Way; however, its characteristics do not allow us to unambiguously classify it as either type of system. If PAndAS-48 is a globular cluster then it is among the most elliptical, isolated, and metal-poor of any seen in the Local Group, extended or otherwise. Conversely, while its properties are generally consistent with those observed for the faint Milky Way dwarfs, it would be a factor of {approx}2-3 smaller in spatial extent than any known counterpart of comparable luminosity.

  8. Expressed sequence tags from the red imported fire ant, Solenopsis invicta: annotation and utilization for discovery of viruses.

    PubMed

    Valles, Steven M; Strong, Charles A; Hunter, Wayne B; Dang, Phat M; Pereira, Roberto M; Oi, David H; Williams, David F

    2008-09-01

    An expression library was created and 2304 clones sequenced from a monogyne colony of Solenopsis invicta. The primary intention of the project was to utilize homologous gene identification to facilitate discovery of viruses infecting this ant pest that could potentially be used in pest management. Additional genes were identified from the ant host and associated pathogens that serve as an important resource for studying these organisms. After assembly and removal of mitochondrial and poor quality sequences, 1054 unique sequences were yielded and deposited into the GenBank database under Accession Nos. EH412746 through EH413799. At least nine expressed sequence tags (ESTs) were identified as possessing microsatellite motifs and 15 ESTs exhibited significant homology with microsporidian genes. These sequences most likely originated from Thelohania solenopsae, a well-characterized microsporidian that infects S. invicta. Six ESTs exhibited significant homology with single-stranded RNA viruses (3B4, 3F6, 11F1, 12G12, 14D5, and 24C10). Subsequent analysis of these putative viral ESTs revealed that 3B4 was most likely a ribosomal gene of S. invicta, 11F1 was a single-stranded RNA (ssRNA) virus contaminant introduced into the colony from the cricket food source, 12G12 appeared to be a plant-infecting tenuivirus also introduced into the colony as a field contaminant, and 3F6, 14D5, and 24C10 were all from a unique ssRNA virus found to infect S. invicta. The sequencing project illustrates the utility of this method for discovery of viruses and pathogens that may otherwise go undiscovered. PMID:18329665

  9. Is the faint young Sun paradox solved?

    NASA Astrophysics Data System (ADS)

    Wolf, E. T.; Toon, O. B.

    2013-12-01

    How did the early Earth remain warm despite weak solar luminosity? The faint young Sun paradox has stubbornly resisted a self-consistent solution since it was first introduced by Sagan and Mullen [1] over four decades ago. However, recent revisions to expected paleo-ocean temperatures [2, 3] along with new results from three-dimensional climate models [4] may allow this long standing problem to be finally put to rest. Here we use a modified version of the Community Atmosphere Model version 3 from the National Center for Atmospheric Research to study early climate. We find that resolving the faint young Sun paradox becomes less problematic when viewing a full representation of the climate system. For the late Archean climate (80% solar constant), relatively modest amounts of CO2 (≤0.02 bar) and CH4 (0.001 bar) yield surface temperatures equal to the present day with no other alterations to climate. Cooler climates with large ice caps but with temperate tropical regions can be supported with considerably smaller greenhouse gas burdens. The incorporation of systematic climate system elements expected for the Archean such as fewer cloud condensation nuclei (CCN) [5], reduced land albedos [5], and an increased atmospheric inventory of N2 [6], can provide a combined 10 to 20 K of additional surface warming given reasonable assumptions. With the inclusion of 0.001 bar of CH4, 2 PAL of N2, reduced land albedos, and reduced CCN, present day mean surface temperatures can be maintained for the earliest Archean (75% solar constant) with only ~0.01 bar of CO2. However, lower requirements for atmospheric CO2 may imply that photochemical hazes were frequent during the Archean. [1] Sagan, C., & Mullen, G. Science 177, 52 (1972) [2] Hren, M.T., Tice, M.M., & Chamberlin, C.P. Nature 462, 205 (2009) [3] Blake. R.E., Chang, S.J., & Lepland, A. Nature 464, 1029 (2010) [4] Wolf, E.T., & Toon, O.B. Astrobiology 13(7), 1 (2013) [5] Rosing, M.T., Bird, D.K., Sleep, N.H., & Bjerrum, C

  10. Genome Sequence of the Red Pigment-Forming Meiothermus taiwanensis Strain RP Isolated from Paniphala Hot Spring, India

    PubMed Central

    Mukherjee, Trinetra; Bose, Sucharita; Sen, Urmimala; Roy, Chayan; Rameez, Moidu Jameela; Ghosh, Wriddhiman

    2016-01-01

    Here we report the draft genome sequence of Meiothermus taiwanensis strain RP (MCC 2966), isolated from the Paniphala hot spring of India, which contains genes encoding for enzymes of the methyl erythritol 4-phosphate (MEP) pathway of isoprenoid biosynthesis and carotenoid backbone synthesis. PMID:27365353

  11. Genome Sequence of the Red Pigment-Forming Meiothermus taiwanensis Strain RP Isolated from Paniphala Hot Spring, India.

    PubMed

    Mukherjee, Trinetra; Bose, Sucharita; Sen, Urmimala; Roy, Chayan; Rameez, Moidu Jameela; Ghosh, Wriddhiman; Mukhopadhyay, Subhra Kanti

    2016-01-01

    Here we report the draft genome sequence of Meiothermus taiwanensis strain RP (MCC 2966), isolated from the Paniphala hot spring of India, which contains genes encoding for enzymes of the methyl erythritol 4-phosphate (MEP) pathway of isoprenoid biosynthesis and carotenoid backbone synthesis. PMID:27365353

  12. THE CONTRIBUTIONS OF INTERACTIVE BINARY STARS TO DOUBLE MAIN-SEQUENCE TURNOFFS AND DUAL RED CLUMP OF INTERMEDIATE-AGE STAR CLUSTERS

    SciTech Connect

    Yang Wuming; Bi Shaolan; Tian Zhijia; Li Tanda; Liu Kang; Meng Xiangcun E-mail: woomyang@gmail.com

    2011-04-20

    Double or extended main-sequence turnoffs (DMSTOs) and dual red clump (RC) were observed in intermediate-age clusters, such as in NGC 1846 and 419. The DMSTOs are interpreted as that the cluster has two distinct stellar populations with differences in age of about 200-300 Myr but with the same metallicity. The dual RC is interpreted as a result of a prolonged star formation. Using a stellar population-synthesis method, we calculated the evolution of a binary-star stellar population. We found that binary interactions and merging can reproduce the dual RC in the color-magnitude diagrams of an intermediate-age cluster, whereas in actuality only a single population exists. Moreover, the binary interactions can lead to an extended main-sequence turnoff (MSTO) rather than DMSTOs. However, the rest of the main sequence, subgiant branch, and first giant branch are hardly spread by the binary interactions. Part of the observed dual RC and extended MSTO may be the results of binary interactions and mergers.

  13. Carbon Dioxide Cycling, Climate, Impacts, and the Faint Young Sun

    NASA Technical Reports Server (NTRS)

    Zahnle, K. J.; Sleep, H. H.

    1999-01-01

    Evidence for relatively mild climates on ancient Earth and Mars has been a puzzle in light of the faint early sun. The geologic evidence, although far from conclusive, would appear to indicate that the surfaces of both planets were, if anything, warmer ca. 3-4 Ga than they are now. The astrophysical argument that the sun ought to have brightened approx. 30% since it reached the main sequence is hard to refute. There results a paradox between the icehouse we expect and the greenhouse we think we see. The usual fix has been to posit massive CO2 atmospheres, although reduced gases (e.g., NH3 or CH4 ) have had their partisans. Evidence against siderite in paleosols dated 2.2-2.75 Ga sets a rough upper limit of 30 PAL (present atmospheric levels) on pCO2 at that time. This is an order of magnitude short of what is needed to defeat the fainter sun. We present here an independent argument against high pCO2 on early Earth that applies not only to the Archean but yet more forcefully to the Hadean era. Additional information is contained in the original extended abstract.

  14. Spectral Indices of Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Gim, Hansung B.; Hales, Christopher A.; Momjian, Emmanuel; Yun, Min Su

    2015-01-01

    The significant improvement in bandwidth and the resultant sensitivity offered by the Karl G. Jansky Very Large Array (VLA) allows us to explore the faint radio source population. Through the study of the radio continuum we can explore the spectral indices of these radio sources. Robust radio spectral indices are needed for accurate k-corrections, for example in the study of the radio - far-infrared (FIR) correlation. We present an analysis of measuring spectral indices using two different approaches. In the first, we use the standard wideband imaging algorithm in the data reduction package CASA. In the second, we use a traditional approach of imaging narrower bandwidths to derive the spectral indices. For these, we simulated data to match the observing parameter space of the CHILES Con Pol survey (Hales et al. 2014). We investigate the accuracy and precision of spectral index measurements as a function of signal-to noise, and explore the requirements to reliably probe possible evolution of the radio-FIR correlation in CHILES Con Pol.

  15. Accurate shear measurement with faint sources

    SciTech Connect

    Zhang, Jun; Foucaud, Sebastien; Luo, Wentao E-mail: walt@shao.ac.cn

    2015-01-01

    For cosmic shear to become an accurate cosmological probe, systematic errors in the shear measurement method must be unambiguously identified and corrected for. Previous work of this series has demonstrated that cosmic shears can be measured accurately in Fourier space in the presence of background noise and finite pixel size, without assumptions on the morphologies of galaxy and PSF. The remaining major source of error is source Poisson noise, due to the finiteness of source photon number. This problem is particularly important for faint galaxies in space-based weak lensing measurements, and for ground-based images of short exposure times. In this work, we propose a simple and rigorous way of removing the shear bias from the source Poisson noise. Our noise treatment can be generalized for images made of multiple exposures through MultiDrizzle. This is demonstrated with the SDSS and COSMOS/ACS data. With a large ensemble of mock galaxy images of unrestricted morphologies, we show that our shear measurement method can achieve sub-percent level accuracy even for images of signal-to-noise ratio less than 5 in general, making it the most promising technique for cosmic shear measurement in the ongoing and upcoming large scale galaxy surveys.

  16. Detection of Optically Faint GEO Debris

    NASA Technical Reports Server (NTRS)

    Seitzer, P.; Lederer, S.; Barker, E.; Cowardin, H.; Abercromby, K.; Silha, J.; Burkhardt, A.

    2014-01-01

    There have been extensive optical surveys for debris at geosynchronous orbit (GEO) conducted with meter-class telescopes, such as those conducted with MODEST (the Michigan Orbital DEbris Survey Telescope, a 0.6-m telescope located at Cerro Tololo in Chile), and the European Space Agency's 1.0-m space debris telescope (SDT) in the Canary Islands. These surveys have detection limits in the range of 18th or 19th magnitude, which corresponds to sizes larger than 10 cm assuming an albedo of 0.175. All of these surveys reveal a substantial population of objects fainter than R = 15th magnitude that are not in the public U.S. Satellite Catalog. To detect objects fainter than 20th magnitude (and presumably smaller than 10 cm) in the visible requires a larger telescope and excellent imaging conditions. This combination is available in Chile. NASA's Orbital Debris Program Office has begun collecting orbital debris observations with the 6.5-m (21.3-ft diameter) "Walter Baade" Magellan telescope at Las Campanas Observatory. The goal is to detect objects as faint as possible from a ground-based observatory and begin to understand the brightness distribution of GEO debris fainter than R = 20th magnitude.

  17. DISCOVERY OF A NEW FAINT DWARF GALAXY ASSOCIATED WITH NGC 253

    SciTech Connect

    Sand, D. J.; Crnojević, D.; Strader, J.; Toloba, E.; Guhathakurta, P.; Caldwell, N.; McLeod, B.; Seth, A. C.

    2014-09-20

    We report the discovery of a new faint dwarf galaxy, which we dub Scl-MM-Dw1, at a projected distance of ∼65 kpc from the spiral galaxy NGC 253. The discovery results from the Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS), a program with the Magellan/Megacam imager to study faint substructure in resolved stellar light around massive galaxies outside of the Local Group. We measure a tip of the red giant branch distance to Scl-MM-Dw1 of D = 3.9 ± 0.5 Mpc, consistent with that of NGC 253, making their association likely. The new dwarf's stellar population is complex, with an old, metal-poor red giant branch (≳10 Gyr, [Fe/H] ∼ –2), and an asymptotic giant branch with an age of ∼500 Myr. Scl-MM-Dw1 has a half-light radius of r{sub h} = 340 ± 50 pc and an absolute magnitude of M{sub V}  = –10.3 ± 0.6 mag, comparable to the Milky Way's satellites at the same luminosity. Once complete, our imaging survey of NGC 253 and other nearby massive galaxies will provide a census of faint substructure in halos beyond the Local Group, both to put our own environment into context and to confront models of hierarchical structure formation.

  18. Seismic strain tensor in the area to the South of Ras Mohamed region during the November-December, 2011 seismic sequence, Northern Red Sea, Egypt.

    NASA Astrophysics Data System (ADS)

    Mohamed, Gad-Elkareem; Abdallah, Saud

    2016-04-01

    We calculated the strain tensor for a sequence of earthquakes that occurred in front of Ras Mohamed, Northern Red Sea within the period from 19th November up to 31st of December 2011. The value and the direction of the strain are evaluated based on a reliable number of focal mechanism solutions. Most of the solutions indicate the dominance of normal faulting. The principal strain axis shows that the deformation is taken up mainly as an extension in the NE-SW direction with a very small crustal thinning rate. The orientation of the principal strain axes deduced from the eigenvectors is in good agreement with the main trend of the focal mechanisms of the selected events (normal type faulting).

  19. Spectroscopic Confirmation of Two Massive Red-sequence-selected Galaxy Clusters at Z Approximately Equal to 1.2 in the Sparcs-North Cluster Survey

    NASA Technical Reports Server (NTRS)

    Muzzin, Adam; Wilson, Gillian; Yee, H.K.C.; Hoekstra, Henk; Gilbank, David; Surace, Jason; Lacy, Mark; Blindert, Kris; Majumdar, Subhabrata; Demarco, Ricardo; Gardner, Jonathan P.; Gladders, Mike; Lonsdale, Carol

    2008-01-01

    The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a deep z -band imaging survey covering the Spitzer SWIRE Legacy fields designed to create the first large homogeneously-selected sample of massive clusters at z > 1 using an infrared adaptation of the cluster red-sequence method. We present an overview of the northern component of the survey which has been observed with CFHT/MegaCam and covers 28.3 deg(sup 2). The southern component of the survey was observed with CTIO/MOSAICII, covers 13.6 deg(sup 2), and is summarized in a companion paper by Wilson et al. (2008). We also present spectroscopic confirmation of two rich cluster candidates at z approx. 1.2. Based on Nod-and- Shuffle spectroscopy from GMOS-N on Gemini there are 17 and 28 confirmed cluster members in SpARCS J163435+402151 and SpARCS J163852+403843 which have spectroscopic redshifts of 1.1798 and 1.1963, respectively. The clusters have velocity dispersions of 490 +/- 140 km/s and 650 +/- 160 km/s, respectively which imply masses (M(sub 200)) of (1.0 +/- 0.9) x 10(exp 14) Stellar Mass and (2.4 +/- 1.8) x 10(exp 14) Stellar Mass. Confirmation of these candidates as bonafide massive clusters demonstrates that two-filter imaging is an effective, yet observationally efficient, method for selecting clusters at z > 1.

  20. Spectroscopic Confirmation of Three Red-sequence Selected Galaxy Clusters at z = 0.87, 1.16, and 1.21 from the SpARCS Survey

    NASA Astrophysics Data System (ADS)

    Demarco, Ricardo; Wilson, Gillian; Muzzin, Adam; Lacy, Mark; Surace, Jason; Yee, H. K. C.; Hoekstra, Henk; Blindert, Kris; Gilbank, David

    2010-03-01

    The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a z'-passband imaging survey of the 50 deg2 Spitzer SWIRE Legacy fields, designed with the primary aim of creating the first large, homogeneously selected sample of massive clusters at z > 1. SpARCS uses an infrared adaptation of the two-filter cluster red-sequence technique. In this paper, we report Keck/LRIS spectroscopic confirmation of two new exceptionally rich galaxy clusters, SpARCS J161315+564930 at z = 0.871 ± 0.002, with 14 high-confidence members and a rest-frame velocity dispersion of σ v = 1230 ± 320 km s-1, and SpARCS J161641+554513 at z = 1.161 ± 0.003, with seven high-confidence members (including one active galactic nucleus) and a rest-frame velocity dispersion of σ v = 950 ± 330 km s-1. We also report confirmation of a third new system, SpARCS J161037+552417 at z = 1.210 ± 0.002, with seven high-confidence members and a rest-frame velocity dispersion of σ v = 410 ± 300 km s-1. These three new spectroscopically confirmed clusters further demonstrate the efficiency and effectiveness of two-filter imaging for detecting bona fide galaxy clusters at high redshift. We conclude by demonstrating that prospects are good for the current generation of surveys aiming to estimate cluster redshifts and masses at z >~ 1 directly from optical-infrared imaging. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  1. Chemical abundances in the multiple sub-giant branch of 47 Tucanae: insights on its faint sub-giant branch component

    NASA Astrophysics Data System (ADS)

    Marino, A. F.; Milone, A. P.; Casagrande, L.; Collet, R.; Dotter, A.; Johnson, C. I.; Lind, K.; Bedin, L. R.; Jerjen, H.; Aparicio, A.; Sbordone, L.

    2016-06-01

    The globular cluster 47 Tuc exhibits a complex sub-giant branch (SGB) with a faint-SGB comprising only about the 10 per cent of the cluster mass and a bright-SGB hosting at least two distinct populations. We present a spectroscopic analysis of 62 SGB stars including 21 faint-SGB stars. We thus provide the first chemical analysis of the intriguing faint-SGB population and compare its abundances with those of the dominant populations. We have inferred abundances of Fe, representative light elements C, N, Na, and Al, α elements Mg and Si for individual stars. Oxygen has been obtained by co-adding spectra of stars on different sequences. In addition, we have analysed 12 stars along the two main RGBs of 47 Tuc. Our principal results are (i) star-to-star variations in C/N/Na among RGB and bright-SGB stars; (ii) substantial N and Na enhancements for the minor population corresponding to the faint-SGB; (iii) no high enrichment in C+N+O for faint-SGB stars. Specifically, the C+N+O of the faint-SGB is a factor of 1.1 higher than the bright-SGB, which, considering random (±1.3) plus systematic errors (±0.3), means that their C+N+O is consistent within observational uncertainties. However, a small C+N+O enrichment for the faint-SGB, similar to what predicted on theoretical ground, cannot be excluded. The N and Na enrichment of the faint-SGB qualitatively agrees with this population possibly being He-enhanced, as suggested by theory. The iron abundance of the bright and faint-SGB is the same to a level of ˜0.10 dex, and no other significant difference for the analysed elements has been detected.

  2. Faint solar radio structures from decametric observations

    NASA Astrophysics Data System (ADS)

    Briand, C.; Zaslavsky, A.; Maksimovic, M.; Zarka, P.; Lecacheux, A.; Rucker, H. O.; Konovalenko, A. A.; Abranin, E. P.; Dorovsky, V. V.; Stanislavsky, A. A.; Melnik, V. N.

    2008-10-01

    Aims: Decameter radio observations of the solar corona reveal the presence of numerous faint frequency drifting emissions, similar to “solar S bursts” which are reported in the literature. We present a statistical analysis of the characteristics of these emissions and propose a mechanism to excite the Langmuir waves thought to be at the origin of these emissions. Methods: The observations were performed between 1998 and 2002 with the Digital Spectro Polarimeter (DSP) receivers operated at the UTR-2 and Nançay decameter radio telescopes in the frequency range 15-30 MHz. Our theoretical explanation is based on Vlasov-Ampère simulations. Results: Based on the frequency drift rate, three populations of structures can be identified. The largest population presents an average negative frequency drift of -0.9 MHz s-1 and a lifetime up to 11 s (median value of 2.72 s). A second population shows a very small frequency drift of -0.1 MHz s-1 and a short lifetime of about 1 s. The third population presents an average positive frequency drift of +0.95 MHz s-1 and a lifetime of up to 3 s. Also, the frequency drift as a function of frequency is consistent with the former results, which present results in higher frequency range. No specific relationship was found between the occurrence of these emissions and the solar cycle or presence of flares. Assuming that these emissions are produced by “electron clouds” propagating the solar corona, we deduce electron velocities of about 3-5 times the electron thermal velocity. As previously shown, a localized, time-dependent modulation of the electron distribution function (heating) leads to low velocity electron clouds (consistent with observations), which, in turn, can generate Langmuir waves and electromagnetic signals by nonlinear processes.

  3. Clouds and the Faint Young Sun Paradox

    NASA Astrophysics Data System (ADS)

    Goldblatt, C.; Zahnle, K. J.

    2011-03-01

    We investigate the role which clouds could play in resolving the Faint Young Sun Paradox (FYSP). Lower solar luminosity in the past means that less energy was absorbed on Earth (a forcing of -50 W m-2 during the late Archean), but geological evidence points to the Earth having been at least as warm as it is today, with only very occasional glaciations. We perform radiative calculations on a single global mean atmospheric column. We select a nominal set of three layered, randomly overlapping clouds, which are both consistent with observed cloud climatologies and reproduced the observed global mean energy budget of Earth. By varying the fraction, thickness, height and particle size of these clouds we conduct a wide exploration of how changed clouds could affect climate, thus constraining how clouds could contribute to resolving the FYSP. Low clouds reflect sunlight but have little greenhouse effect. Removing them entirely gives a forcing of +25 W m-2 whilst more modest reduction in their efficacy gives a forcing of +10 to +15 W m-2. For high clouds, the greenhouse effect dominates. It is possible to generate +50 W m-2 forcing from enhancing these, but this requires making them 3.5 times thicker and 14 K colder than the standard high cloud in our nominal set and expanding their coverage to 100% of the sky. Such changes are not credible. More plausible changes would generate no more than +15 W m-2 forcing. Thus neither fewer low clouds nor more high clouds can provide enough forcing to resolve the FYSP. Decreased surface albedo can contribute no more than +5 W m-2 forcing. Some models which have been applied to the FYSP do not include clouds at all. These overestimate the forcing due to increased CO2 by 20 to 25% when pCO2 is 0.01 to 0.1 bar.

  4. The ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Smith, Harding E.

    1999-01-01

    As part of the ISO-IRAS Faint Galaxy Survey ISO Satellite observations of over 600 IRAS sources have been obtained with the ISOCAM instrument. Because our survey strategy involved relatively short integrations, great care was required in developing analysis software including cosmic-ray and transient removal and calibration. These observations have now been through final pipeline processing at IPAC and ground-based follow-up is ongoing. The observations are for sources from two samples: a " Filler' sample selected to be at z greater than 0.1 and a fainter sample which selected for the highest redshift galaxies in the IRAS survey, with redshifts 0.2 less than z less than 1.0. I now have obtained ground-based follow-up spectrophotometry at Lick and Palomar observatories for 100 LFIRGs with 0.1 less than z less than 0.7. Our observations have confirmed that these systems are comparable to nearby LFIRGs such as Arp 220, with L (sub -)(fir) greater than 10(exp 11) L(sub -) sun and typically HII/Liner optical excitation. About 10% of the galaxies show true AGN (Sy2) excitation. Based on our work on a nearby complete sample of LFIRGS, we believe that the majority of these systems are luminous Starbursts, thus this project is tracing the luminous end of the galaxy star-forming luminosity function - the (infrared) star-formation history of the Universe to z approx. 1, a topic of some considerable recent interest. A by-product of these ISOCAM observations is approximately 1 square degree of deep 2 microns pointings outside the IRAS error boxes, allowing us an independent estimate of the mid-infrared log N - log S relation. Ground-based observations of this sample are continuing.

  5. a Faint and Lonely Brown Dwarf in the Solar Vicinity

    NASA Astrophysics Data System (ADS)

    1997-04-01

    Discovery of KELU-1 Promises New Insights into Strange Objects Brown Dwarfs are star-like objects which are too small to become real stars, yet too large to be real planets. Their mass is too small to ignite those nuclear processes which are responsible for the large energies and high temperatures of stars, but it is much larger than that of the planets we know in our solar system. Until now, very few Brown Dwarfs have been securely identified as such. Two are members of double-star systems, and a few more are located deep within the Pleiades star cluster. Now, however, Maria Teresa Ruiz of the Astronomy Department at Universidad de Chile (Santiago de Chile), using telescopes at the ESO La Silla observatory, has just discovered one that is all alone and apparently quite near to us. Contrary to the others which are influenced by other objects in their immediate surroundings, this new Brown Dwarf is unaffected and will thus be a perfect object for further investigations that may finally allow us to better understand these very interesting celestial bodies. It has been suggested that Brown Dwarfs may constitute a substantial part of the unseen dark matter in our Galaxy. This discovery may therefore also have important implications for this highly relevant research area. Searching for nearby faint stars The story of this discovery goes back to 1987 when Maria Teresa Ruiz decided to embark upon a long-term search (known as the Calan-ESO proper-motion survey ) for another type of unusual object, the so-called White Dwarfs , i.e. highly evolved, small and rather faint stars. Although they have masses similar to that of the Sun, such stars are no larger than the Earth and are therefore extremely compact. They are particularly interesting, because they most probably represent the future end point of evolution of our Sun, some billions of years from now. For this project, the Chilean astronomer obtained large-field photographic exposures with the 1-m ESO Schmidt telescope at

  6. Astronomical capabilities of the Faint Object Spectrograph on Space Telescope

    NASA Technical Reports Server (NTRS)

    Harms, R. J.

    1982-01-01

    Examples of scientific observing programs planned with the Faint Object Spectrograph on Space Telescope are presented. An overview of the spectrograph design and operation is presented. The expected astronomical performance of the instrument is described in some detail.

  7. NASA Researches the 'FaINT' Side of Sonic Booms

    NASA Video Gallery

    As the latest in a continuing progression of NASA supersonics research projects aimed at reducing or mitigating the effect of sonic booms, the Farfield Investigation of No Boom Threshold, or FaINT,...

  8. A comparison of coding sequence and cytogenetic localization of the myostatin gene in the dog, red fox, arctic fox and Chinese raccoon dog.

    PubMed

    Grzes, M; Nowacka-Woszuk, J; Szczerbal, I; Czerwinska, J; Gracz, J; Switonski, M

    2009-01-01

    The gene encoding myostatin (MSTN), due to its crucial function for growth of skeletal muscle mass, is an important candidate for muscularity. In this study we analyzed the nucleotide sequence and FISH localization of this gene in 4 canids, including 3 farm species. The nucleotide sequence of the MSTN coding fragment turned out to be highly conserved, since its identity among the studied species was very high and varied between 99.4 and 99.7%. Only 1, widely spread, silent single nucleotide polymorphism (SNP) was found in exon 1 of the Chinese raccoon dog. The MSTN gene was localized close to the centromere in one-armed chromosomes of the dog (37q11) and bi-armed chromosomes of the red fox (16p11) and arctic fox (10q11), with an exception of the Chinese raccoon dog chromosome (2q14-q21). This chromosome is orthologous to 3 canine chromosomes and thus the MSTN was found more interstitially. Our results are in agreement with the hypothesis that karyotypes of the canids evolved mainly through centric fusion/fission events, while tandem fusions occurred rarely. PMID:20016167

  9. THE ORIGIN OF [O II] IN POST-STARBURST AND RED-SEQUENCE GALAXIES IN HIGH-REDSHIFT CLUSTERS

    SciTech Connect

    Lemaux, B. C.; Lubin, L. M.; Kocevski, D.; Shapley, A.; Gal, R. R.; Squires, G. K.

    2010-06-20

    We present the first results from a near-IR spectroscopic campaign of the Cl1604 supercluster at z {approx} 0.9 and the cluster RX J1821.6+6827 at z {approx} 0.82 to investigate the nature of [O II] {lambda}3727 emission in cluster galaxies at high redshift. Of the 401 members in Cl1604 and RX J1821+6827 confirmed using the Keck II/DEIMOS spectrograph, 131 galaxies have detectable [O II] emission with no other signs of current star formation activity, as well as strong absorption features indicative of a well-established older stellar population. The combination of these features suggests that the primary source of [O II] emission in these galaxies is not a result of star formation processes, but rather due to the presence of a low-ionization nuclear emission-line region (LINER) or Seyfert component. Using the NIRSPEC spectrograph on the Keck II 10 m telescope, 19 such galaxies were targeted, as well as 6 additional [O II]-emitting cluster members that exhibited signs of ongoing star formation activity. Nearly half ({approx}47%) of the 19 [O II]-emitting, absorption-line-dominated galaxies exhibit [O II] to H{alpha} equivalent width (EW) ratios higher than unity, the typical observed value for star-forming galaxies, with an EW distribution similar to that observed for LINERs at low redshift. A majority ({approx}68%) of these 19 galaxies are classified as LINER/Seyfert based primarily on the emission-line ratio of [N II] {lambda}6584 and H{alpha}. The fraction of LINER/Seyferts increases to {approx}85% for red [O II]-emitting, absorption-line-dominated galaxies. The LINER/Seyfert galaxies in our Cl1604 sample exhibit average L([O II])/L(H{alpha}) ratios that are significantly higher than that observed in populations of star-forming galaxies, suggesting that [O II] is a poor indicator of star formation in a significant fraction of high-redshift cluster members. From the prevalence of [O II]-emitting, absorption-line-dominated galaxies in both systems and the fraction

  10. Seeing Red

    NASA Technical Reports Server (NTRS)

    2008-01-01

    volcanos. Though the plume deposits are red, the plume itself is blue, because it is composed of very tiny particles that preferentially scatter blue light, like smoke. Also faintly visible in the left image is the pale-colored Prometheus plume, almost on the edge of the disk on the equator at the 9 o'clock position.

    Io was 2.4 million kilometers from the spacecraft when the picture was taken, and the center of Io's disk is at 77 degrees West longitude, 5 degrees South latitude. The solar phase angle was 107 degrees.

  11. The Role of Major Gas-rich Mergers on the Evolution of Galaxies from the Blue Cloud to the Red Sequence

    NASA Astrophysics Data System (ADS)

    Guo, Rui; Hao, Cai-Na; Xia, X. Y.; Mao, Shude; Shi, Yong

    2016-07-01

    With the aim of exploring the fast evolutionary path from the blue cloud of star-forming galaxies to the red sequence of quiescent galaxies in the local universe, we select a local advanced merging infrared luminous and ultraluminous galaxy (adv-merger (U)LIRGs) sample and perform careful dust extinction corrections to investigate their positions in the star formation rate–M *, u ‑ r, and NUV ‑ r color–mass diagrams. The sample consists of 89 (U)LIRGs at the late merger stage, obtained from cross-correlating the Infrared Astronomical Satellite Point Source Catalog Redshift Survey and 1 Jy ULIRGs samples with the Sloan Digital Sky Survey DR7 database. Our results show that 74 % +/- 5 % of adv-merger (U)LIRGs are localized above the 1σ line of the local star-forming galaxy main sequence. We also find that all adv-merger (U)LIRGs are more massive than and as blue as the blue cloud galaxies after corrections for Galactic and internal dust extinctions, with 95 % +/- 2 % and 81 % +/- 4 % of them outside the blue cloud on the u ‑ r and NUV ‑ r color–mass diagrams, respectively. These results, combined with the short timescale for exhausting the molecular gas reservoir in adv-merger (U)LIRGs (3× {10}7 to 3× {10}8 years), imply that the adv-merger (U)LIRGs are likely at the starting point of the fast evolutionary track previously proposed by several groups. While the number density of adv-merger (U)LIRGs is only ∼ 0.1 % of the blue cloud star-forming galaxies in the local universe, this evolutionary track may play a more important role at high redshift.

  12. The faint galaxy contribution to the diffuse extragalactic background light

    NASA Technical Reports Server (NTRS)

    Cole, Shaun; Treyer, Marie-Agnes; Silk, Joseph

    1992-01-01

    Models of the faint galaxy contribution to the diffuse extragalactic background light are presented, which are consistent with current data on faint galaxy number counts and redshifts. The autocorrelation function of surface brightness fluctuations in the extragalactic diffuse light is predicted, and the way in which these predictions depend on the cosmological model and assumptions of biasing is determined. It is confirmed that the recent deep infrared number counts are most compatible with a high density universe (Omega-0 is approximately equal to 1) and that the steep blue counts then require an extra population of rapidly evolving blue galaxies. The faintest presently detectable galaxies produce an interesting contribution to the extragalactic diffuse light, and still fainter galaxies may also produce a significant contribution. These faint galaxies still only produce a small fraction of the total optical diffuse background light, but on scales of a few arcminutes to a few degrees, they produce a substantial fraction of the fluctuations in the diffuse light.

  13. Chemical enrichment in Ultra-Faint Dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Romano, Donatella

    2016-08-01

    Our view of the Milky Way's satellite population has radically changed after the discovery, ten years ago, of the first Ultra-Faint Dwarf galaxies (UFDs). These extremely faint, dark-matter dominated, scarcely evolved stellar systems are found in ever-increasing number in our cosmic neighbourhood and constitute a gold-mine for studies of early star formation conditions and early chemical enrichment pathways. Here we show what can be learned from the measurements of chemical abundances in UFD stars read through the lens of chemical evolution studies, point out the limitations of the classic approach, and discuss the way to go to improve the models.

  14. 1. Dyea Dock looking south. Note faint evenly spaced circular ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Dyea Dock looking south. Note faint evenly spaced circular dark pieces of grass up through the middle of the picture indicating posts making up the pier. Photograph made from park service cherry picker. - Dyea Dock & Association (Ruins), Skagway, Skagway, AK

  15. CONFIRMATION OF FAINT DWARF GALAXIES IN THE M81 GROUP

    SciTech Connect

    Chiboucas, Kristin; Jacobs, Bradley A.; Tully, R. Brent; Karachentsev, Igor D. E-mail: bjacobs@ifa.hawaii.edu E-mail: ikar@luna.sao.ru

    2013-11-01

    We have followed up on the results of a 65 deg{sup 2} CFHT/MegaCam imaging survey of the nearby M81 Group searching for faint and ultra-faint dwarf galaxies. The original survey turned up 22 faint candidate dwarf members. Based on two-color HST ACS/WFC and WFPC2 photometry, we now confirm 14 of these as dwarf galaxy members of the group. Distances and stellar population characteristics are discussed for each. To a completeness limit of M{sub r{sup '}}= -10, we find a galaxy luminosity function slope of –1.27 ± 0.04 for the M81 Group. In this region, there are now 36 M81 Group members known, including 4 blue compact dwarfs; 8 other late types including the interacting giants M81, NGC 3077, and M82; 19 early type dwarfs; and at least 5 potential tidal dwarf galaxies. We find that the dSph galaxies in M81 appear to lie in a flattened distribution, similar to that found for the Milky Way and M31. One of the newly discovered dSph galaxies has properties similar to the ultra-faint dwarfs being found in the Local Group with a size R{sub e} ∼ 100 pc and total magnitude estimates M{sub r{sup '}}= -6.8 and M{sub I} ∼ –9.1.

  16. The Historical Demography and Genetic Variation of the Endangered Cycas multipinnata (Cycadaceae) in the Red River Region, Examined by Chloroplast DNA Sequences and Microsatellite Markers

    PubMed Central

    Gong, Yi-Qing; Zhan, Qing-Qing; Nguyen, Khang Sinh; Nguyen, Hiep Tien; Wang, Yue-Hua; Gong, Xun

    2015-01-01

    Cycas multipinnata C.J. Chen & S.Y. Yang is a cycad endemic to the Red River drainage region that occurs under evergreen forest on steep limestone slopes in Southwest China and northern Vietnam. It is listed as endangered due to habitat loss and over-collecting for the ornamental plant trade, and only several populations remain. In this study, we assess the genetic variation, population structure, and phylogeography of C. multipinnata populations to help develop strategies for the conservation of the species. 60 individuals from six populations were used for chloroplast DNA (cpDNA) sequencing and 100 individuals from five populations were genotyped using 17 nuclear microsatellites. High genetic differentiation among populations was detected, suggesting that pollen or seed dispersal was restricted within populations. Two main genetic clusters were observed in both the cpDNA and microsatellite loci, corresponding to Yunnan China and northern Vietnam. These clusters indicated low levels of gene flow between the regions since their divergence in the late Pleistocene, which was inferred from both Bayesian and coalescent analysis. In addition, the result of a Bayesian skyline plot based on cpDNA portrayed a long history of constant population size followed by a decline in the last 50,000 years of C. multipinnata that was perhaps affected by the Quaternary glaciations, a finding that was also supported by the Garza-Williamson index calculated from the microsatellite data. The genetic consequences produced by climatic oscillations and anthropogenic disturbances are considered key pressures on C. multipinnata. To establish a conservation management plan, each population of C. multipinnata should be recognized as a Management Unit (MU). In situ and ex situ actions, such as controlling overexploitation and creating a germplasm bank with high genetic diversity, should be urgently implemented to preserve this species. PMID:25689828

  17. The historical demography and genetic variation of the endangered Cycas multipinnata (Cycadaceae) in the red river region, examined by chloroplast DNA sequences and microsatellite markers.

    PubMed

    Gong, Yi-Qing; Zhan, Qing-Qing; Nguyen, Khang Sinh; Nguyen, Hiep Tien; Wang, Yue-Hua; Gong, Xun

    2015-01-01

    Cycas multipinnata C.J. Chen & S.Y. Yang is a cycad endemic to the Red River drainage region that occurs under evergreen forest on steep limestone slopes in Southwest China and northern Vietnam. It is listed as endangered due to habitat loss and over-collecting for the ornamental plant trade, and only several populations remain. In this study, we assess the genetic variation, population structure, and phylogeography of C. multipinnata populations to help develop strategies for the conservation of the species. 60 individuals from six populations were used for chloroplast DNA (cpDNA) sequencing and 100 individuals from five populations were genotyped using 17 nuclear microsatellites. High genetic differentiation among populations was detected, suggesting that pollen or seed dispersal was restricted within populations. Two main genetic clusters were observed in both the cpDNA and microsatellite loci, corresponding to Yunnan China and northern Vietnam. These clusters indicated low levels of gene flow between the regions since their divergence in the late Pleistocene, which was inferred from both Bayesian and coalescent analysis. In addition, the result of a Bayesian skyline plot based on cpDNA portrayed a long history of constant population size followed by a decline in the last 50,000 years of C. multipinnata that was perhaps affected by the Quaternary glaciations, a finding that was also supported by the Garza-Williamson index calculated from the microsatellite data. The genetic consequences produced by climatic oscillations and anthropogenic disturbances are considered key pressures on C. multipinnata. To establish a conservation management plan, each population of C. multipinnata should be recognized as a Management Unit (MU). In situ and ex situ actions, such as controlling overexploitation and creating a germplasm bank with high genetic diversity, should be urgently implemented to preserve this species. PMID:25689828

  18. The high-mass end of the red sequence at z ˜ 0.55 from SDSS-III/BOSS: completeness, bimodality and luminosity function

    NASA Astrophysics Data System (ADS)

    Montero-Dorta, Antonio D.; Bolton, Adam S.; Brownstein, Joel R.; Swanson, Molly; Dawson, Kyle; Prada, Francisco; Eisenstein, Daniel; Maraston, Claudia; Thomas, Daniel; Comparat, Johan; Chuang, Chia-Hsun; McBride, Cameron K.; Favole, Ginevra; Guo, Hong; Rodríguez-Torres, Sergio; Schneider, Donald P.

    2016-09-01

    We have developed an analytical method based on forward-modelling techniques to characterize the high-mass end of the red sequence (RS) galaxy population at redshift z ˜ 0.55, from the DR10 BOSS (Baryon Oscillation Spectroscopic Survey) CMASS spectroscopic sample, which comprises ˜600 000 galaxies. The method, which follows an unbinned maximum likelihood approach, allows the deconvolution of the intrinsic CMASS colour-colour-magnitude distributions from photometric errors and selection effects. This procedure requires modelling the covariance matrix for the i-band magnitude, g - r colour and r - i colour using Stripe 82 multi-epoch data. Our results indicate that the error-deconvolved intrinsic RS distribution is consistent, within the photometric uncertainties, with a single point (<0.05 mag) in the colour-colour plane at fixed magnitude, for a narrow redshift slice. We have computed the high-mass end (0.55Mi ≲ -22) of the 0.55i-band RS luminosity function (RS LF) in several redshift slices within the redshift range 0.52 < z < 0.63. In this narrow redshift range, the evolution of the RS LF is consistent, within the uncertainties in the modelling, with a passively evolving model with Φ* = (7.248 ± 0.204) × 10- 4 Mpc-3 mag-1, fading at a rate of 1.5 ± 0.4 mag per unit redshift. We report RS completeness as a function of magnitude and redshift in the CMASS sample, which will facilitate a variety of galaxy-evolution and clustering studies using BOSS. Our forward-modelling method lays the foundations for future studies using other dark-energy surveys like the Extended Baryon Oscillation Spectroscopic Survey or the Dark Energy Spectroscopic Instrument, which are affected by the same type of photometric blurring/selection effects.

  19. Phylogeny of geminivirus coat protein sequences and digital PCR aid in identifying Spissistilus festinus (Say) as a vector of Grapevine red blotch-associated virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grapevine red blotch-associated virus (GRBaV) is a newly identified virus of grapevines, and a putative member of a new genus within the family Geminiviridae. This virus is associated with red blotch disease that was first reported in California in 2008. It affects the profitability of vineyards by ...

  20. KIM 3: An Ultra-faint Star Cluster in the Constellation of Centaurus

    NASA Astrophysics Data System (ADS)

    Kim, Dongwon; Jerjen, Helmut; Mackey, Dougal; Da Costa, Gary S.; Milone, Antonino P.

    2016-04-01

    We report the discovery of an ultra-faint star cluster in the constellation of Centaurus. This new stellar system, Kim 3, features a half-light radius of {r}h={2.29}-0.52+1.28 pc and a total luminosity of MV = +0.7 ± 0.3. Approximately 26 stars are identified as candidate member stars down to four magnitudes below the main-sequence turn-off, which makes Kim 3 the least luminous star cluster known to date. The compact physical size and extreme low luminosity place it close to faint star clusters in the size-luminosity plane. The stellar population of Kim 3 appears to be relatively young ({9.5}-1.7+3.0 Gyr) and metal-poor ([Fe/H]\\quad =\\quad -{1.6}-0.30+0.45) at a heliocentric distance of {15.14}-0.28+1.00 kpc. The cluster lacks a well-defined center, and a small but prominent group of stars consistent with the Kim 3 isochrone is present approximately 9.7 pc in projection south of the cluster center. Both are signs of the cluster being in the final stage of tidal disruption.

  1. A CCD survey for faint high-latitude carbon stars

    NASA Technical Reports Server (NTRS)

    Green, Paul J.; Margon, Bruce; Anderson, Scott F.; Cook, Kem H.

    1994-01-01

    We describe a wide-area CCD survey to search for faint high-latitude carbon (FHLC) stars. Carbon giants provide excellent probes of the structure and kinematics of the outer Galactic halo. We use two-color photometric selection with large-format CCDs to cover 52 sq deg of sky to a depth of about V = 18. Of 94 faint C star candidates from our own CCD survey, one highly ranked V = 17 candidate was found to have a strong carbon and CN bands. We estimate that, to a depth of V = 18, the surface density of FHLC stars is 0.02 deg(exp -2). An updated FHLC sample is used to constrain halo kinematic and structural parameters. Although larger samples are needed, the effective radius of FHLC giants, assuming a de Vancouleurs law distribution, is larger than that for Galactic globular clusters.

  2. X-ray Counterparts of Infrared Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Schartel, Norbert

    2011-10-01

    Infrared Faint Radio Sources (IFRS) are radio sources with extremely faint or even absent infrared emission in deep Spitzer Surveys. Models of their spectral energy distributions, the ratios of radio to infrared flux densities and their steep radio spectra strongly suggest that IFRS are AGN at high redshifts (2

  3. FAINT FUZZY STAR CLUSTERS IN NGC 1023 AS REMNANTS OF MERGED STAR CLUSTER COMPLEXES

    SciTech Connect

    Bruens, R. C.; Kroupa, P.; Fellhauer, M. E-mail: pavel@astro.uni-bonn.de

    2009-09-10

    In the lenticular galaxy NGC 1023 a third population of globular clusters (GCs), called faint fuzzies (FFs), was discovered next to the blue and red GC populations by Larsen and Brodie. While these FFs have colors comparable to the red population, the new population is fainter, larger (R{sub eff}>7 pc) and, most importantly, shows clear signs of corotation with the galactic disk of NGC 1023. We present N-body simulations verifying the hypothesis that these disk-associated FFs are related to the young massive cluster complexes (CCs) observed by Bastian et al. in M51, who discovered a mass-radius relation for these CCs. Our models have an initial configuration based on the observations from M51 and are placed on various orbits in a galactic potential derived for NGC 1023. All computations end up with a stable object containing 10%-60% of the initial CC mass after an integration time of 5 Gyr. A conversion to visual magnitudes demonstrates that the resulting objects cover exactly the observed range for FFs. Moreover, the simulated objects show projected half-mass radii between 3.6 and 13.4 pc, in good agreement with the observed FF sizes. We conclude that objects like the young massive CCs in M51 are likely progenitors of the FFs observed in NGC 1023.

  4. The optical-infrared colour distribution of a statistically complete sample of faint field spheroidal galaxies

    NASA Astrophysics Data System (ADS)

    Menanteau, F.; Ellis, R. S.; Abraham, R. G.; Barger, A. J.; Cowie, L. L.

    1999-10-01

    In hierarchical models, where spheroidal galaxies are primarily produced via a continuous merging of disc galaxies, the number of intrinsically red systems at faint limits will be substantially lower than in `traditional' models where the bulk of star formation was completed at high redshifts. In this paper we analyse the optical-near-infrared colour distribution of a large flux-limited sample of field spheroidal galaxies identified morphologically from archival Hubble Space Telescope data. The I_814-HK' colour distribution for a sample jointly limited at I_814<23mag and HK'<19.5mag is used to constrain their star formation history. We compare visual and automated methods for selecting spheroidals from our deep HST images and, in both cases, detect a significant deficit of intrinsically red spheroidals relative to the predictions of high-redshift monolithic-collapse models. However, the overall space density of spheroidals (irrespective of colour) is not substantially different from that seen locally. Spectral synthesis modelling of our results suggests that high-redshift spheroidals are dominated by evolved stellar populations polluted by some amount of subsidiary star formation. Despite its effect on the optical-infrared colour, this star formation probably makes only a modest contribution to the overall stellar mass. We briefly discuss the implications of our results in the context of earlier predictions based on models where spheroidals assemble hierarchically.

  5. The faint end of the galaxy luminosity function

    NASA Technical Reports Server (NTRS)

    Treyer, Marie A.; Silk, Joseph

    1994-01-01

    The evolution of the B- and K-band luminosity functions of galaxies is inferred in a relatively model-independent way from deep spectroscopic and photometric surveys. We confirm earlier evidence by Eales for an increase in the amplitude of the B-band galaxy luminosity function at modest redshift (z less than or approx. 0.2). We find in addition that the slope of the faint end of the luminosity function must systematically steepen and progress toward more luminous galaxies with increasing lookback time, assuming that the galaxy redshift distribution may be smoothly extrapolated 2 mag fainter than observed, as suggested by recent gravitational lensing studies. This evolution is shown to be color-dependent, and we predict the near-infrared color distribution of faint galaxies. The luminosity function of blue (B - K less than or approx. 4) galaxies in the range 0.2 less than or approx. z less than or approx. 1 can be represented by a Schechter function with characteristic light density phi(sup *) L(sup *) comparable to that of present-day late-type galaxies, but with a steeper faint end slope alpha approx. 1.4.

  6. Spectrophotometric Redshifts in the Faint Infrared Grism Survey

    NASA Astrophysics Data System (ADS)

    Pharo, John; Malhotra, Sangeeta; Rhoads, James E.

    2016-06-01

    We have combined HST grism spectroscopy and deep broadband imaging to measure spectro-photometric redshifts (SPZs) of faint galaxies. Using a technique pioneered by Ryan et al. 2007, one can combine spectra and photometry to yield an SPZ that is more accurate than pure photometric redshifts, and can probe more deeply than ground-based spectroscopic redshifts. By taking mid-resolution spectra from the HST Faint Infrared Grism Survey (FIGS), SPZs can be found for measurements potentially down to 27th magnitude (the typical brightness of a dwarf galaxy at redshift ∼1.5). A galaxy’s redshift is vital for understanding its place in the growth and evolution of the universe. The measurement of high-accuracy SPZs for FIGS sources will improve the faint-end and high-redshift portions of the luminosity function, and make possible a robust analysis of the FIGS fields for signs of Large Scale Structure (LSS). The improved redshift and distance measurements allowed for the identification of a structure at z=0.83 in one of the FIGS fields.

  7. Faint Submillimeter Galaxies Behind the Frontier Field Clusters

    NASA Astrophysics Data System (ADS)

    Hsu, Li-Yen; Cowie, Lennox; Barger, Amy; Wang, Wei-Hao; Chen, Chian-Chou

    2015-08-01

    Faint submillimeter galaxies are the major contributors to the submillimeter extragalactic background light and hence the dominant star-forming population in the dusty universe. Determining how much these galaxies overlap the optically selected samples is critical to fully account for the cosmic star formation history. To explore this faint submillimeter population, we have been observing nine galaxy clusters with the SCUBA-2 camera on the James Clerk Maxwell Telescope, including five of the clusters in the HST Frontier Fields program. We have also been using the Submillimeter Array to determine the positions of our detected sources precisely. Our recent observations have discovered several high-redshift dusty galaxies with far-infrared luminosities similar to that of the Milky Way or luminous infrared galaxies but which are undetected in current deep radio, optical and near-infrared images. These remarkable results suggest that a substantial amount of star formation in even the faint submillimeter population may be hidden from rest-frame optical surveys.

  8. Can waterbelt climates resolve the faint young Sun paradox?

    NASA Astrophysics Data System (ADS)

    Wolf, E. T.; Toon, O. B.

    2012-12-01

    Ancient sediments indicate that liquid water and primitive life were ubiquitous on the Archean Earth despite the faint young Sun. However, energy balance and radiative-convective models require improbably high greenhouse gas abundances to obtain non-glacial climates, violating constraints from geochemical data. A self-consistent solution to the faint young Sun paradox has remained elusive. Here we use the NCAR Community Atmosphere Model version 3 with thermodynamic ocean and sea ice components to simulate the climate circa 2.8 billion years ago. To maintain present day surface temperatures, 0.06 bar of CO2 in a 1 bar atmosphere is required to compensate for a 20 percent reduction in the solar constant. However, waterbelt climates having stable low latitude sea ice margins can be maintained with as little as 500 ppm of CO2 and no additional trace greenhouse species. With 5000 ppm of CO2 nearly 60 percent of the planet remains free from ice. The early Earth is resistant to hard snowball glaciations instead favoring waterbelt climates. The coexistence of a faint young Sun and a weak greenhouse does not exclude the presence of liquid water at the Archean surface.

  9. Differentiation between Focal Malignant Marrow-Replacing Lesions and Benign Red Marrow Deposition of the Spine with T2*-Corrected Fat-Signal Fraction Map Using a Three-Echo Volume Interpolated Breath-Hold Gradient Echo Dixon Sequence

    PubMed Central

    Kim, Yong Pyo; Kannengiesser, Stephan; Paek, Mun-Young; Chung, Tae-Sub; Yoo, Yeon Hwa; Yoon, Choon-Sik; Song, Ho-Taek; Lee, Young Han; Suh, Jin-Suck

    2014-01-01

    Objective To assess the feasibility of T2*-corrected fat-signal fraction (FF) map by using the three-echo volume interpolated breath-hold gradient echo (VIBE) Dixon sequence to differentiate between malignant marrow-replacing lesions and benign red marrow deposition of vertebrae. Materials and Methods We assessed 32 lesions from 32 patients who underwent magnetic resonance imaging after being referred for assessment of a known or possible vertebral marrow abnormality. The lesions were divided into 21 malignant marrow-replacing lesions and 11 benign red marrow depositions. Three sequences for the parameter measurements were obtained by using a 1.5-T MR imaging scanner as follows: three-echo VIBE Dixon sequence for FF; conventional T1-weighted imaging for the lesion-disc ratio (LDR); pre- and post-gadolinium enhanced fat-suppressed T1-weighted images for the contrast-enhancement ratio (CER). A region of interest was drawn for each lesion for parameter measurements. The areas under the curve (AUC) of the parameters and their sensitivities and specificities at the most ideal cutoff values from receiver operating characteristic curve analysis were obtained. AUC, sensitivity, and specificity were respectively compared between FF and CER. Results The AUCs of FF, LDR, and CER were 0.96, 0.80, and 0.72, respectively. In the comparison of diagnostic performance between the FF and CER, the FF showed a significantly larger AUC as compared to the CER (p = 0.030), although the difference of sensitivity (p = 0.157) and specificity (p = 0.157) were not significant. Conclusion Fat-signal fraction measurement using T2*-corrected three-echo VIBE Dixon sequence is feasible and has a more accurate diagnostic performance, than the CER, in distinguishing benign red marrow deposition from malignant bone marrow-replacing lesions. PMID:25469090

  10. The Chemical Evolution of the Bootes I Ultra-faint Dwarf Galaxy

    NASA Astrophysics Data System (ADS)

    Frebel, Anna; Norris, John E.; Gilmore, Gerard; Wyse, Rosemary F. G.

    2016-08-01

    We present chemical abundance measurements of two metal-poor red giant stars in the ultra-faint dwarf galaxy Boötes I, based on Magellan/MIKE high-resolution spectra. For Boo-980, with {{[Fe/H]}}=-3.1, we present the first elemental abundance measurements, while Boo-127, with {{[Fe/H]}}=-2.0, shows abundances in good agreement with previous measurements. Light and iron-peak element abundance ratios in the two Boötes I stars, as well as those of most other Boötes I members, collected from the literature, closely resemble those of regular metal-poor halo stars. Neutron-capture element abundances Sr and Ba are systematically lower than the main halo trend and also show a significant abundance spread. Overall, this is similar to what has been found for other ultra-faint dwarf galaxies. We apply corrections to the carbon abundances (commensurate with stellar evolutionary status) of the entire sample and find 21% of stars to be carbon-enhanced metal-poor (CEMP) stars, compared to 13% without using the carbon correction. We reassess the metallicity distribution functions for the CEMP stars and non-CEMP stars, and confirm earlier claims that CEMP stars might belong to a different, earlier population. Applying a set of abundance criteria to test to what extent Boötes I could be a surviving first galaxy suggests that it is one of the earliest assembled systems that perhaps received gas from accretion from other clouds in the system, or from swallowing a first galaxy or building block type object. This resulted in the two stellar populations observable today. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  11. Particle-based ablation model for faint meteors

    NASA Astrophysics Data System (ADS)

    Stokan, E.; Campbell-Brown, M.

    2014-07-01

    Modeling the ablation of meteoroids as they enter the atmosphere is a way of determining their physical structure and elemental composition. This can provide insight into the structure of parent bodies when combined with an orbit computed from observations. The Canadian Automated Meteor Observatory (CAMO) is a source of new, high-resolution observations of faint meteors [1]. These faint objects tend to have pre-atmospheric masses around 10^{-5} kg, corresponding to a radius of 1 mm. A wide-field camera with a 28° field of view provides guidance to a high-resolution camera that tracks meteors in flight with 1.5° field of view. Meteors are recorded with a scale of 4 m per pixel at a range of 135 km, at 110 frames per second, allowing us to investigate detailed meteor morphology. This serves as an important new constraint for ablation models, in addition to meteor brightness (lightcurves) and meteoroid deceleration. High-resolution observations of faint meteors have revealed that contemporary ablation models are not able to predict meteor morphology, even while matching the observed lightcurve and meteoroid deceleration [2]. This implies that other physical processes, in addition to fragmentation, must be considered for faint meteor ablation. We present a new, particle-based approach to modeling the ablation of small meteoroids. In this model, we simulate the collisions between atmospheric particles and the meteoroid to determine the rate of evaporation and deceleration. Subsequent collisions simulated between evaporated meteoroid particles and ambient atmospheric particles then produce light that would be observed by high-resolution cameras. Preliminary results show simultaneous agreement with meteor morphology, lightcurves, and decelerations recorded with CAMO. A sample comparison of simulated and observed meteor morphology is given in the attached figure. Several meteoroids are well-represented as solid, stony bodies, but some require modeling as a dustball [3

  12. Eye redness

    MedlinePlus

    Bloodshot eyes; Red eyes; Scleral infection; Conjunctival infection ... There are many causes of a red eye or eyes. Some are medical emergencies and some are a cause for concern, but not an emergency. Others are nothing to worry about. ...

  13. Red Clover

    MedlinePlus

    ... 17):2057–2071. Red clover. Natural Medicines Comprehensive Database Web site. Accessed at www.naturaldatabase.com on July 22, 2009. Red clover ( Trifolium pratense ). Natural Standard Database Web site. Accessed at www.naturalstandard.com on July ...

  14. Red clover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red clover (Trifolium pratense L.) is an important forage legume grown on approximately 4 million hectares worldwide. An estimated 2.8 million kg of red clover seed per year was produced worldwide in 2005-2007. This amount of seed would be enough to maintain approximately 4 million hectares of red...

  15. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... Imaging SpectroRadiometer (MISR) image of the Red Sea was acquired on August 13, 2000. Located between the East African coast and the Saudi Arabian peninsula, the Red Sea got its name because the blooms of a type of algae,  Trichodesmium ...

  16. THE EVOLUTION OF DUSTY STAR FORMATION IN GALAXY CLUSTERS TO z = 1: SPITZER INFRARED OBSERVATIONS OF THE FIRST RED-SEQUENCE CLUSTER SURVEY

    SciTech Connect

    Webb, T. M. A.; O'Donnell, D.; Coppin, Kristen; Faloon, Ashley; Geach, James E.; Noble, Allison; Yee, H. K. C.; Gilbank, David; Ellingson, Erica; Gladders, Mike; Muzzin, Adam; Wilson, Gillian; Yan, Renbin

    2013-10-01

    We present the results of an infrared (IR) study of high-redshift galaxy clusters with the MIPS camera on board the Spitzer Space Telescope. We have assembled a sample of 42 clusters from the Red-Sequence Cluster Survey-1 over the redshift range 0.3 < z < 1.0 and spanning an approximate range in mass of 10{sup 14-15} M {sub ☉}. We statistically measure the number of IR-luminous galaxies in clusters above a fixed inferred IR luminosity of 2 × 10{sup 11} M {sub ☉}, assuming a star forming galaxy template, per unit cluster mass and find it increases to higher redshift. Fitting a simple power-law we measure evolution of (1 + z){sup 5.1±1.9} over the range 0.3 < z < 1.0. These results are tied to the adoption of a single star forming galaxy template; the presence of active galactic nuclei, and an evolution in their relative contribution to the mid-IR galaxy emission, will alter the overall number counts per cluster and their rate of evolution. Under the star formation assumption we infer the approximate total star formation rate per unit cluster mass (ΣSFR/M {sub cluster}). The evolution is similar, with ΣSFR/M {sub cluster} ∼ (1 + z){sup 5.4±1.9}. We show that this can be accounted for by the evolution of the IR-bright field population over the same redshift range; that is, the evolution can be attributed entirely to the change in the in-falling field galaxy population. We show that the ΣSFR/M {sub cluster} (binned over all redshift) decreases with increasing cluster mass with a slope (ΣSFR/M{sub cluster}∼M{sub cluster}{sup -1.5±0.4}) consistent with the dependence of the stellar-to-total mass per unit cluster mass seen locally. The inferred star formation seen here could produce ∼5%-10% of the total stellar mass in massive clusters at z = 0, but we cannot constrain the descendant population, nor how rapidly the star-formation must shut-down once the galaxies have entered the cluster environment. Finally, we show a clear decrease in the number of IR

  17. Use of Simple Sequence Repeat (SSR) markers for DNA fingerprinting and diversity analysis of sugarcane (Saccharum spp.) cultivars resistant and susceptible to red rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years SSR markers have been used widely for the genetic analysis. The objective of present research was to use SSR markers to develop DNA-based genetic identification and analyze genetic relationship of sugarcane cultivars grown in Pakistan either resistant or susceptible to red rot. Twent...

  18. Revisiting the concept of behavior patterns in animal behavior with an example from food-caching sequences in wolves (Canis lupus), coyotes (Canis latrans), and red foxes (Vulpes vulpes).

    PubMed

    Gadbois, Simon; Sievert, Olivia; Reeve, Catherine; Harrington, F H; Fentress, J C

    2015-01-01

    We discuss the history, conceptualization, and relevance of behavior patterns in modern ethology by explaining the evolution of the concepts of fixed action patterns and modal action patterns. We present the movement toward a more flexible concept of natural action sequences with significant degrees of (production and expressive) freedom. An example is presented with the food caching behavior of three Canidae species: red fox (Vulpes vulpes), coyote (Canis latrans) and gray wolf (Canis lupus). Evolutionary, ecological, and neuroecological/neuroethological arguments are presented to explain the difference in levels of complexity and stereotypy between Canis and Vulpes. This article is part of a Special Issue entitled: Canine Behavior. PMID:25446624

  19. DISCOVERY OF A CLOSE PAIR OF FAINT DWARF GALAXIES IN THE HALO OF CENTAURUS A

    SciTech Connect

    Crnojević, D.; Sand, D. J.; Caldwell, N.; McLeod, B.; Guhathakurta, P.; Toloba, E.; Simon, J. D.; Strader, J.

    2014-11-10

    As part of the Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS), we report the discovery of a pair of faint dwarf galaxies (CenA-MM-Dw1 and CenA-MM-Dw2) at a projected distance of ∼90 kpc from the nearby elliptical galaxy NGC 5128 (CenA). We measure a tip of the red giant branch distance to each dwarf, finding D = 3.63 ± 0.41 Mpc for CenA-MM-Dw1 and D = 3.60 ± 0.41 Mpc for CenA-MM-Dw2, both of which are consistent with the distance to NGC 5128. A qualitative analysis of the color-magnitude diagrams indicates stellar populations consisting of an old, metal-poor red giant branch (≳12 Gyr, [Fe/H] ∼ –1.7 to –1.9). In addition, CenA-MM-Dw1 seems to host an intermediate-age population as indicated by its candidate asymptotic giant branch stars. The derived luminosities (M{sub V} = –10.9 ± 0.3 for CenA-MM-Dw1 and –8.4 ± 0.6 for CenA-MM-Dw2) and half-light radii (r{sub h} = 1.4 ± 0.04 kpc for CenA-MM-Dw1 and 0.36 ± 0.08 kpc for CenA-MM-Dw2) are consistent with those of Local Group dwarfs. CenA-MM-Dw1's low central surface brightness (μ {sub V,} {sub 0} = 27.3 ± 0.1 mag arcsec{sup –2}) places it among the faintest and most extended M31 satellites. Most intriguingly, CenA-MM-Dw1 and CenA-MM-Dw2 have a projected separation of only 3 arcmin (∼3 kpc): we are possibly observing the first, faint satellite of a satellite in an external group of galaxies.

  20. Whence the red panda?

    PubMed

    Flynn, J J; Nedbal, M A; Dragoo, J W; Honeycutt, R L

    2000-11-01

    The evolutionary history of the red panda (Ailurus fulgens) plays a pivotal role in the higher-level phylogeny of the "bear-like" arctoid carnivoran mammals. Characters from morphology and molecules have provided inconsistent evidence for placement of the red panda. Whereas it certainly is an arctoid, there has been major controversy about whether it should be placed with the bears (ursids), ursids plus pinnipeds (seals, sea lions, walrus), raccoons (procyonids), musteloids (raccoons plus weasels, skunks, otters, and badgers [mustelids]), or as a monotypic lineage of uncertain phylogenetic affinities. Nucleotide sequence data from three mitochondrial genes and one nuclear intron were analyzed, with more complete taxonomic sampling of relevant taxa (arctoids) than previously available in analyses of primary molecular data, to clarify the phylogenetic relationships of the red panda to other arctoid carnivorans. This study provides detailed phylogenetic analyses (both parsimony and maximum-likelihood) of primary character data for arctoid carnivorans, including bootstrap and decay indices for all arctoid nodes, and three statistical tests of alternative phylogenetic hypotheses for the placement of the red panda. Combined phylogenetic analyses reject the hypotheses that the red panda is most closely related to the bears (ursids) or to the raccoons (procyonids). Rather, evidence from nucleotide sequences strongly support placement of the red panda within a broad Musteloidea (sensu lato) clade, including three major lineages (the red panda, the skunks [mephitids], and a clearly monophyletic clade of procyonids plus mustelids [sensu stricto, excluding skunks]). Within the Musteloidea, interrelationships of the three major lineages are unclear and probably are best considered an unresolved trichotomy. These data provide compelling evidence for the relationships of the red panda and demonstrate that small taxonomic sample sizes can result in misleading or possibly erroneous

  1. Distribution of Faint Atomic Gas in Hickson Compact Groups

    NASA Astrophysics Data System (ADS)

    Borthakur, Sanchayeeta; Yun, Min Su; Verdes-Montenegro, Lourdes; Heckman, Timothy M.; Zhu, Guangtun; Braatz, James A.

    2015-10-01

    We present 21 cm H i observations of four Hickson Compact Groups (HCGs) with evidence for a substantial intragroup medium using the Robert C. Byrd Green Bank Telescope (GBT). By mapping H i emission in a region of 25‧ × 25‧ (140–650 kpc) surrounding each HCG, these observations provide better estimates of H i masses. In particular, we detected 65% more H i than that detected in the Karl G. Jansky Very Large Array (VLA) imaging of HCG 92. We also identify whether the diffuse gas has the same spatial distribution as the high surface brightness (HSB) H i features detected in the VLA maps of these groups by comparing the H i strengths between the observed and modeled masses based on VLA maps. We found that the H i observed with the GBT has a similar spatial distribution to the HSB structures in HCG 31 and HCG 68. Conversely, the observed H i distributions in HCG 44 and HCG 92 were extended and showed significant offsets from the modeled masses. Most of the faint gas in HCG 44 lies to the northeast–southwest region and in HCG 92 lies in the northwest region of their respective groups. The spatial and dynamical similarities between the total (faint+HSB) and the HSB H i indicate that the faint gas is of tidal origin. We found that the gas will survive ionization by the cosmic UV background and the escaping ionizing photons from the star-forming regions and stay primarily neutral for at least 500 Myr.

  2. Stellar Ultraviolet Rocket Research Program. [faint object spectrograph

    NASA Technical Reports Server (NTRS)

    1984-01-01

    A 1/4 meter ultraviolet spectrometer, developed to measure the ultraviolet flux from several standard type stars was flown successfully on Aerobee rockets. The ultraviolet flux from alpha Lyr, eta U Ma, zeta Oph, delta Ori, alpha CMa, beta CMa, and alpha Leo were measured. These values agreed with the OAO data obtained by Code in the 1200 to 3400 A region to + or - 9%. The design and calibration of a faint object spectrometer for observing stars and nebula with a 3 A resolution and a 3% accuracy in a 60 second observation are discussed.

  3. CCD time-resolved photometry of faint cataclysmic variables. III

    NASA Technical Reports Server (NTRS)

    Howell, Steve B.; Szkody, Paula; Kreidl, Tobias J.; Mason, Keith O.; Puchnarewicz, E. M.

    1990-01-01

    CCD time-resolved photometry in V, B, and near-IR for 17 faint cataclysmic variables (CVs) is presented and analyzed. The data are obtained at Kitt Peak National Observatory, the Perkins reflector, Lowell Observatory, and the Observatorio del Roque de los Muchachos from April-June 1989. The degree of variability and periodicities for the CVs are examined. It is observed that the variability of most of the stars is consistent with CV class behavior. Orbital periods for five CVs are determined, and three potential eclipsing systems are detected.

  4. Are the infrared-faint radio sources pulsars?

    NASA Astrophysics Data System (ADS)

    Cameron, A. D.; Keith, M.; Hobbs, G.; Norris, R. P.; Mao, M. Y.; Middelberg, E.

    2011-07-01

    Infrared-faint radio sources (IFRS) are objects which are strong at radio wavelengths but undetected in sensitive Spitzer observations at infrared wavelengths. Their nature is uncertain and most have not yet been associated with any known astrophysical object. One possibility is that they are radio pulsars. To test this hypothesis we undertook observations of 16 of these sources with the Parkes Radio Telescope. Our results limit the radio emission to a pulsed flux density of less than 0.21 mJy (assuming a 50 per cent duty cycle). This is well below the flux density of the IFRS. We therefore conclude that these IFRS are not radio pulsars.

  5. The Faint Object Camera for the Space Telescope

    NASA Astrophysics Data System (ADS)

    Bartholomae, K.-P.; Schmidt, G.

    1981-05-01

    The Faint Object Camera (FOC), one of the four axial scientific instruments located at the focal plane of the NASA Space Telescope, is described. The FOC has overall dimensions of approximately 0.9 x 0.9 x 2.2 cu m, a total weight of about 322 kg, and an average power consumption per orbit of less than 150 W. The FOC is made up of two complete and independent camera systems, each with its dedicated three mirrors optical relay and photon detector device operating in a wavelength range of 1200 A to 7000 A.

  6. Surprising Rapid Collapse of Sirius B from Red Giant to White Dwarf Through Mass Transfer to Sirius a

    NASA Astrophysics Data System (ADS)

    Yousef, Shahinaz; Ali, Ola

    2013-03-01

    Sirius was observed in antiquity as a red star. In his famous astronomy textbook the Almagest written 140 AD, Ptolemy described the star Sirius as fiery red. He curiously depicted it as one of six red-colored stars. The other five are class M and K stars, such as Arcturus and Betelgeuse. Apparent confirmation in ancient Greek and Roman sources are found and Sirius was also reported red in Europe about 1400 years ago. Sirius must have changed to a white dwarf in the night of Ascension. The star chapter in the Quran started with "by the star as it collapsed (1) your companion have not gone astray nor being misled (2), and in verse 49 which is the rotation period of the companion Sirius B around Sirius A, it is said" He is the Lord of Sirius (49). If Sirius actually was red what could have caused it to change into the brilliant bluish-white star we see today? What the naked eye perceives as a single star is actually a binary star system, consisting of a white main sequence star of spectral type A1V, termed Sirius A, and a faint white dwarf companion of spectral type DA2, termed Sirius B. The red color indicates that the star seen then was a red giant. It looks that what they have seen in antiquity was Sirius B which was then a red giant and it collapsed to form a white dwarf. Since there is no evidence of a planetary nebula, then the red Sirius paradox can be solved in terms of stellar evolution with mass transfer. Sirius B was the most massive star which evolved to a red giant and filled the Roche lobe. Mass transfer to Sirius A occurred through the Lagrangian point. Sirius A then became more massive while Sirius B lost mass and shrank. Sirius B then collapsed abruptly into a white dwarf. In the case of Algol, Ptolmy observed it as white star but it was red at the time of El sufi. At present it is white. The rate of mass transfer from Sirius B to Sirius A, and from Algol B to A is estimated from observational data of colour change from red to bullish white to be 0

  7. ALMA Census of Faint 1.2 mm Sources Down to ~ 0.02 mJy: Extragalactic Background Light and Dust-poor, High-z Galaxies

    NASA Astrophysics Data System (ADS)

    Fujimoto, Seiji; Ouchi, Masami; Ono, Yoshiaki; Shibuya, Takatoshi; Ishigaki, Masafumi; Nagai, Hiroshi; Momose, Rieko

    2016-01-01

    We present statistics of 133 faint 1.2 mm continuum sources detected in about 120 deep Atacama Large Millimeter/submillimeter Array (ALMA) pointing data that include all the archival deep data available by 2015 June. We derive number counts of 1.2 mm continuum sources down to 0.02 mJy partly with the assistance of gravitational lensing, and find that the total integrated 1.2 mm flux of the securely identified sources is {22.9}-5.6+6.7 Jy deg-2 which corresponds to {104}-25+31% of the extragalactic background light (EBL) measured by Cosmic Background Explorer observations. These results suggest that the major 1.2 mm EBL contributors are sources with 0.02 mJy, and that very faint 1.2 mm sources with ≲0.02 mJy contribute negligibly to the EBL with the possible flattening and/or truncation of number counts in this very faint flux regime. To understand the physical origin of our faint ALMA sources, we measure the galaxy bias bg by the counts-in-cells technique, and place a stringent upper limit of bg < 3.5 that is not similar to bg values of massive distant red galaxies and submillimeter galaxies but comparable to those of UV-bright, star-forming BzK galaxies (sBzKs) and Lyman break galaxies (LBGs). Moreover, in the optical and near-infrared (NIR) deep fields, we identify optical-NIR counterparts for 59% of our faint ALMA sources, the majority of which have luminosities, colors, and the IRX-β relation the same as sBzKs and LBGs. We thus conclude that about a half of our faint ALMA sources are dust-poor, high-z galaxies as known as sBzKs and LBGs in optical studies, and that these faint ALMA sources are not miniature (U)LIRGs simply scaled down with the infrared brightness.

  8. A white dwarf companion to the main-sequence star 4 Omicron(1) Orionis and the binary hypothesis for the origin of peculiar red giants

    NASA Technical Reports Server (NTRS)

    Ake, Thomas B.; Johnson, Hollis R.

    1988-01-01

    Ultraviolet spectra of the peculiar red giants (PRGs) called MS stars are investigated, and the discovery of a white dwarf (WD) companion to the MS star 4 Omicron(1) Orionis is reported. The observations and data analysis are discussed and compared with those for field WDs in order to derive parameters for the WD and the luminosity of the primary. Detection limits for the other MS stars investigated are derived, and the binary hypothesis for PRGs is reviewed.

  9. Detectability of Ultra Faint Dwarf Galaxies with Gaia

    NASA Astrophysics Data System (ADS)

    Mateu, C.; Antoja, T.; Aguilar, L.; Figueras, F.; Brown, A.; Antiche, E.; Hernández-Pérez, F.; Valenzuela, O.; Aparicio, A.; Hidalgo, S.; Velázquez, H.

    2014-07-01

    We present a technique to detect Ultra-Faint Dwarf Galaxies (UFDs) in the Galactic Halo, using sky and proper motion information.The method uses wavelet transforms to detect peaks in the sky and proper motion planes, and to evaluate the probability of these being stochastic fluctuations. We aim to map thoroughly the detection limits of this technique. For this, we have produced a library of 15,000 synthetic UFDs, embedded in the Gaia Universe Model Snapshot (GUMS) background (Robin et al. 2012), each at a different distance, different luminosity, half-light radius, velocity dispersion and center-of-mass velocity, varying in ranges that extend well beyond those spanned by known classical and ultra-faint dSphs. We use these synthetic UFDs as a benchmark to characterize the completeness and detection limits of our technique, and present our results as a function of different physical and observable parameters of the UFDs (see full poster for more details at https://gaia.ub.edu/Twiki/pub/GREATITNFC/ProgramFinalconference/Poster_UFGX_Bcn_C_Mateu.pdf).

  10. Faint Blue Objects in the Hubble Deep Field North

    NASA Astrophysics Data System (ADS)

    Kilic, M.; von Hippel, T.; Mendez, R. A.; Winget, D. E.

    2005-07-01

    Using the deepest and finest resolution images of the Universe acquired with the Hubble Space Telescope and a similar image taken 7 years later for the Great Observatories Origins Deep Survey, we have derived proper motions for the point sources in the Hubble Deep Field-North. Two faint blue objects, HDF2234 and HDF3072, are found to display significant proper motions, 10.0 ± 2.5 and 15.5 ± 3.8 mas yr-1. Photometric distances and tangential velocities for these stars are consistent with disk white dwarfs located at ≈500 pc. At least one of these two objects now appears spectroscopically to be a white dwarf (Kilic et al., in preparation). The faint blue objects analyzed by Ibata et al. (1999) and Mendez & Minniti (2000) do not show any significant proper motion; they are not halo white dwarfs and they do not contribute to the Galactic dark matter. These objects are likely to be distant AGN.

  11. Rapid Rotation of Low-mass Red Giants Using APOKASC: A Measure of Interaction Rates on the Post-main-sequence

    NASA Astrophysics Data System (ADS)

    Tayar, Jamie; Ceillier, Tugdual; García-Hernández, D. A.; Troup, Nicholas W.; Mathur, Savita; García, Rafael A.; Zamora, O.; Johnson, Jennifer A.; Pinsonneault, Marc H.; Mészáros, Szabolcs; Allende Prieto, Carlos; Chaplin, William J.; Elsworth, Yvonne; Hekker, Saskia; Nidever, David L.; Salabert, David; Schneider, Donald P.; Serenelli, Aldo; Shetrone, Matthew; Stello, Dennis

    2015-07-01

    We investigate the occurrence rate of rapidly rotating (v{sin}i >10 km s-1), low-mass giant stars in the Apache Point Observatory Galaxy Evolution Experiment-Kepler (APOKASC) fields with asteroseismic mass and surface gravity measurements. Such stars are likely merger products and their frequency places interesting constraints on stellar population models. We also identify anomalous rotators, i.e., stars with 5 km s-1 < v{sin}i < 10 km s-1 that are rotating significantly faster than both angular momentum evolution predictions and the measured rates of similar stars. Our data set contains fewer rapid rotators than one would expect given measurements of the Galactic field star population, which likely indicates that asteroseismic detections are less common in rapidly rotating red giants. The number of low-mass moderate (5-10 km s-1) rotators in our sample gives a lower limit of 7% for the rate at which low-mass stars interact on the upper red giant branch because single stars in this mass range are expected to rotate slowly. Finally, we classify the likely origin of the rapid or anomalous rotation where possible. KIC 10293335 is identified as a merger product and KIC 6501237 is a possible binary system of two oscillating red giants.

  12. Color and Variability Characteristics of Point Sources in the Faint Sky Variability Survey

    SciTech Connect

    Huber, M E; Everett, M E; Howell, S B

    2005-03-07

    The authors present an analysis of the color and variability characteristics for point sources in the Faint Sky Variability Survey (FSVS). The FSVS cataloged {approx} 23 square degrees in BVI filters from {approx} 16-24 mag to investigate variability in faint sources at moderate to high Galactic latitudes. Point source completeness is found to be >83% for a selected representative sample (V - 17.5-22.0 mag, B-V = 0.0-1.5) containing both photometric B, V detections and 80% of the time-sampled V data available compared to a basic internal source completeness of 99%. Multi-epoch (10-30) observations in V spanning minutes to years modeled by light curve simulations reveal amplitude sensitivities to {approx} 0.015-0.075 mag over a representative V = 18-22 mag range. Periodicity determinations appear viable to time-scales of an order 1 day or less using the most sampled fields ({approx} 30 epochs). The fraction of point sources is found to be generally variable at 5-8% over V = 17.5-22.0 mag. For V brighter than 19 mag, the variable population is dominated by low amplitude (< 0.05 mag) and blue (B-V < 0.35) sources, possibly representing a population of {gamma} Doradus stars. Overall, the dominant population of variable sources are bluer than B-V = 0.65 and have Main Sequence colors, likely reflecting larger populations of RR Lyrae, SX Phe, {gamma} Doradus, and W UMa variables.

  13. Hydra II: A Faint and Compact Milky Way Dwarf Galaxy Found in the Survey of the Magellanic Stellar History

    NASA Astrophysics Data System (ADS)

    Martin, Nicolas F.; Nidever, David L.; Besla, Gurtina; Olsen, Knut; Walker, Alistair R.; Vivas, A. Katherina; Gruendl, Robert A.; Kaleida, Catherine C.; Muñoz, Ricardo R.; Blum, Robert D.; Saha, Abhijit; Conn, Blair C.; Bell, Eric F.; Chu, You-Hua; Cioni, Maria-Rosa L.; de Boer, Thomas J. L.; Gallart, Carme; Jin, Shoko; Kunder, Andrea; Majewski, Steven R.; Martinez-Delgado, David; Monachesi, Antonela; Monelli, Matteo; Monteagudo, Lara; Noël, Noelia E. D.; Olszewski, Edward W.; Stringfellow, Guy S.; van der Marel, Roeland P.; Zaritsky, Dennis

    2015-05-01

    We present the discovery of a new dwarf galaxy, Hydra II, found serendipitously within the data from the ongoing Survey of the Magellanic Stellar History conducted with the Dark Energy Camera on the Blanco 4 m Telescope. The new satellite is compact ({{r}h}=68 ± 11 pc) and faint ({{M}V}=-4.8 ± 0.3), but well within the realm of dwarf galaxies. The stellar distribution of Hydra II in the color-magnitude diagram is well-described by a metal-poor ([Fe/H]=-2.2) and old (13 Gyr) isochrone and shows a distinct blue horizontal branch, some possible red clump stars, and faint stars that are suggestive of blue stragglers. At a heliocentric distance of 134 ± 10 kpc, Hydra II is located in a region of the Galactic halo that models have suggested may host material from the leading arm of the Magellanic Stream. A comparison with N-body simulations hints that the new dwarf galaxy could be or could have been a satellite of the Magellanic Clouds.

  14. FAINT TIDAL FEATURES IN GALAXIES WITHIN THE CANADA-FRANCE-HAWAII TELESCOPE LEGACY SURVEY WIDE FIELDS

    SciTech Connect

    Atkinson, Adam M.; Abraham, Roberto G.; Ferguson, Annette M. N.

    2013-03-01

    We present an analysis of the detectability of faint tidal features in galaxies from the wide-field component of the Canada-France-Hawaii Telescope Legacy Survey. Our sample consists of 1781 luminous (M{sub r{sup '}}<-19.3 mag) galaxies in the magnitude range 15.5 mag < r' < 17 mag and in the redshift range 0.04 < z < 0.2. Although we have classified tidal features according to their morphology (e.g., streams, shells, and tails), we do not attempt to interpret them in terms of their physical origin (e.g., major versus minor merger debris). Instead, we provide a catalog that is intended to provide raw material for future investigations which will probe the nature of low surface brightness substructure around galaxies. We find that around 12% of the galaxies in our sample show clear tidal features at the highest confidence level. This fraction rises to about 18% if we include systems with convincing, albeit weaker tidal features, and to 26% if we include systems with more marginal features that may or may not be tidal in origin. These proportions are a strong function of rest-frame color and of stellar mass. Linear features, shells, and fans are much more likely to occur in massive galaxies with stellar masses >10{sup 10.5} M {sub Sun }, and red galaxies are twice as likely to show tidal features than are blue galaxies.

  15. Correction of the geomagnetically induced image motion problem on the Hubble Space Telescope's Faint Object Spectrograph

    NASA Astrophysics Data System (ADS)

    Fitch, John E.; Hartig, George F.; Beaver, Edward A.; Hier, Richard G.

    1993-11-01

    During the Science Verification phase of the Hubble Space Telescope mission, it was determined that the Faint Object Spectrograph's (FOS) Red detector displayed significant image motions which correlated with orbital changes in the geomagnetic field. The Blue detector exhibited similar but less pronounced motions. The cause of this motion was determined to be inadequate magnetic shielding of the instrument's Digicon detectors. The results of these motions were decreases in onboard target acquisition accuracy, spectral resolution, and photometric accuracy. The Space Telescope Science Institute and the FOS Investigation Definition Team, set about correcting this Geomagnetically-induced Image Motion Problem (GIMP) through a real-time on-board correction scheme. This correction required modifications to almost all aspects of the HST ground system as well as additional NSSC1 flight software and the use of an existing software 'hook' in the FOS microprocessor firmware. This paper presents a detailed description of the problem, the proposed solution, and results of on-orbit testing of the correction mechanism.

  16. Faint Tidal Features in Galaxies within the Canada-France-Hawaii Telescope Legacy Survey Wide Fields

    NASA Astrophysics Data System (ADS)

    Atkinson, Adam M.; Abraham, Roberto G.; Ferguson, Annette M. N.

    2013-03-01

    We present an analysis of the detectability of faint tidal features in galaxies from the wide-field component of the Canada-France-Hawaii Telescope Legacy Survey. Our sample consists of 1781 luminous (M_{r^\\prime }<-19.3 mag) galaxies in the magnitude range 15.5 mag < r' < 17 mag and in the redshift range 0.04 < z < 0.2. Although we have classified tidal features according to their morphology (e.g., streams, shells, and tails), we do not attempt to interpret them in terms of their physical origin (e.g., major versus minor merger debris). Instead, we provide a catalog that is intended to provide raw material for future investigations which will probe the nature of low surface brightness substructure around galaxies. We find that around 12% of the galaxies in our sample show clear tidal features at the highest confidence level. This fraction rises to about 18% if we include systems with convincing, albeit weaker tidal features, and to 26% if we include systems with more marginal features that may or may not be tidal in origin. These proportions are a strong function of rest-frame color and of stellar mass. Linear features, shells, and fans are much more likely to occur in massive galaxies with stellar masses >1010.5 M ⊙, and red galaxies are twice as likely to show tidal features than are blue galaxies.

  17. Hubble Space Telescope: Faint object spectrograph instrument handbook. Version 1.1

    NASA Technical Reports Server (NTRS)

    Ford, Holland C. (Editor)

    1990-01-01

    The Faint Object Spectrograph (FOS) has undergone substantial rework since the 1985 FOS Instrument Handbook was published, and we are now more knowledgeable regarding the spacecraft and instrument operations requirements and constraints. The formal system for observation specification has also evolved considerably, as the GTO programs were defined in detail. This supplement to the FOS Instrument Handbook addresses the important aspects of these changes, to facilitate proper selection and specification of FOS observing programs. Since the Handbook was published, the FOS red detector has been replaced twice, first with the best available spare in 1985 (which proved to have a poor, and steadily degrading red response), and later with a newly developed Digicon, which exhibits a high, stable efficiency and a dark-count rate less than half that of its predecessors. Also, the FOS optical train was realigned in 1987-88 to eliminate considerable beam-vignetting losses, and the collimators were both removed and recoated for greater reflectivity. Following the optics and detector rework, the FOS was carefully recalibrated (although only ambient measurements were possible, so the far-UV characteristics could not be re-evaluated directly). The resulting efficiency curves, including improved estimates of the telescope throughput, are shown. A number of changes in the observing-mode specifications and addition of several optional parameters resulted as the Proposal Instructions were honed during the last year. Target-brightness limitations, which have only recently been formulated carefully, are described. Although these restrictions are very conservative, it is imperative that the detector safety be guarded closely, especially during the initial stages of flight operations. Restrictions on the use of the internal calibration lamps and aperture-illumination sources (TA LEDs), also resulting from detector safety considerations, are outlined. Finally, many changes have been made to

  18. HAWAII QUASAR AND T DWARF SURVEY. I. METHOD AND DISCOVERY OF FAINT FIELD ULTRACOOL DWARFS ,

    SciTech Connect

    Kakazu, Yuko; Capak, Peter L.; Hu, Esther M.; Liu, Michael C.; Wainscoat, Richard J.; Wang Weihao

    2010-11-01

    The Hawaii Quasar and T dwarf survey (HQT Survey) is a wide-field, red optical survey carried out with the Suprime-Cam mosaic CCD camera on the 8.2 m Subaru telescope. The HQT survey is designed to search for low-luminosity (M{sub AB1450} < -23) quasars at high redshift (z>5.7) as well as T dwarfs, both of which are selected by their very red I - z' colors. We use an optical narrowband filter NB816 to break a well-known I - z' color degeneracy between high-z quasars and foreground M and L dwarfs, which are more numerous than quasars. This paper is the first in a series of papers from the HQT survey and we report on the discovery of six faint (19 {<=} J {<=} 20) ultracool dwarfs found over a {approx}9.3 deg{sup 2} area with a limiting magnitude of z'{sub AB} {<=} 23.3. These dwarfs were confirmed by near-IR imaging and/or spectroscopy conducted at various facilities on Mauna Kea. With estimated distances of 60-170 pc, these are among the most distant spectroscopically confirmed field brown dwarfs to date. Limits on the proper motions of these ultracool dwarfs suggest that they are old members of the Galactic disk, though future follow-up observations are necessary to minimize errors. Our finding rate of ultracool dwarfs is within model predictions of Liu et al. However, the large brightening amplitude ({approx}1 mag) previously reported for the L/T transition objects appears to overpredict the numbers. We also examine how the survey field latitude affects the survey sensitivity to the vertical scale height of ultracool dwarfs.

  19. Witnessing the Birth of the Red Sequence: ALMA High-resolution Imaging of [C II] and Dust in Two Interacting Ultra-red Starbursts at z = 4.425

    NASA Astrophysics Data System (ADS)

    Oteo, I.; Ivison, R. J.; Dunne, L.; Smail, I.; Swinbank, A. M.; Zhang, Z.-Y.; Lewis, A.; Maddox, S.; Riechers, D.; Serjeant, S.; Van der Werf, P.; Biggs, A. D.; Bremer, M.; Cigan, P.; Clements, D. L.; Cooray, A.; Dannerbauer, H.; Eales, S.; Ibar, E.; Messias, H.; Michałowski, M. J.; Pérez-Fournon, I.; van Kampen, E.

    2016-08-01

    Exploiting the sensitivity and spatial resolution of the Atacama Large Millimeter/submillimeter Array, we have studied the morphology and the physical scale of the interstellar medium—both gas and dust—in SGP 38326, an unlensed pair of interacting starbursts at z = 4.425. SGP 38326 is the most luminous star bursting system known at z > 4, with a total IR luminosity of L IR ˜ 2.5 × 1013 L ⊙ and a star formation rate of ˜ 4500 M ⊙ yr‑1. SGP 38326 also contains a molecular gas reservoir among the most massive yet found in the early universe, and it is the likely progenitor of a massive, red-and-dead elliptical galaxy at z ˜ 3. Probing scales of ˜0.″1 or ˜800 pc we find that the smooth distribution of the continuum emission from cool dust grains contrasts with the more irregular morphology of the gas, as traced by the [C ii] fine structure emission. The gas is also extended over larger physical scales than the dust. The velocity information provided by the resolved [C ii] emission reveals that the dynamics of the two interacting components of SGP 38326 are each compatible with disk-like, ordered rotation, but also reveals an ISM which is turbulent and unstable. Our observations support a scenario where at least a subset of the most distant extreme starbursts are highly dissipative mergers of gas-rich galaxies.

  20. Witnessing the Birth of the Red Sequence: ALMA High-resolution Imaging of [C II] and Dust in Two Interacting Ultra-red Starbursts at z = 4.425

    NASA Astrophysics Data System (ADS)

    Oteo, I.; Ivison, R. J.; Dunne, L.; Smail, I.; Swinbank, A. M.; Zhang, Z.-Y.; Lewis, A.; Maddox, S.; Riechers, D.; Serjeant, S.; Van der Werf, P.; Biggs, A. D.; Bremer, M.; Cigan, P.; Clements, D. L.; Cooray, A.; Dannerbauer, H.; Eales, S.; Ibar, E.; Messias, H.; Michałowski, M. J.; Pérez-Fournon, I.; van Kampen, E.

    2016-08-01

    Exploiting the sensitivity and spatial resolution of the Atacama Large Millimeter/submillimeter Array, we have studied the morphology and the physical scale of the interstellar medium—both gas and dust—in SGP 38326, an unlensed pair of interacting starbursts at z = 4.425. SGP 38326 is the most luminous star bursting system known at z > 4, with a total IR luminosity of L IR ∼ 2.5 × 1013 L ⊙ and a star formation rate of ∼ 4500 M ⊙ yr‑1. SGP 38326 also contains a molecular gas reservoir among the most massive yet found in the early universe, and it is the likely progenitor of a massive, red-and-dead elliptical galaxy at z ∼ 3. Probing scales of ∼0.″1 or ∼800 pc we find that the smooth distribution of the continuum emission from cool dust grains contrasts with the more irregular morphology of the gas, as traced by the [C ii] fine structure emission. The gas is also extended over larger physical scales than the dust. The velocity information provided by the resolved [C ii] emission reveals that the dynamics of the two interacting components of SGP 38326 are each compatible with disk-like, ordered rotation, but also reveals an ISM which is turbulent and unstable. Our observations support a scenario where at least a subset of the most distant extreme starbursts are highly dissipative mergers of gas-rich galaxies.

  1. The galaxy luminosity function in groups and clusters: the faint-end upturn and the connection to the field luminosity function

    NASA Astrophysics Data System (ADS)

    Lan, Ting-Wen; Ménard, Brice; Mo, Houjun

    2016-07-01

    We characterize the luminosity functions of galaxies residing in z ˜ 0 groups and clusters over the broadest ranges of luminosity and mass reachable by the Sloan Digital Sky Survey. Our measurements cover four orders of magnitude in luminosity, down to about Mr = -12 mag or L = 107 L⊙, and three orders of magnitude in halo mass, from 1012 to 1015 M⊙. We find a characteristic scale, Mr ˜ -18 mag or L ˜ 109 L⊙, below which the slope of the luminosity function becomes systematically steeper. This trend is present for all halo masses and originates mostly from red satellites. This ubiquitous faint-end upturn suggests that it is formation, rather than halo-specific environmental effect, that plays a major role in regulating the stellar masses of faint satellites. We show that the satellite luminosity functions can be described in a simple manner by a double Schechter function with amplitudes scaling with halo mass over the entire range of observables. Combining these conditional luminosity functions with the dark matter halo mass function, we accurately recover the entire field luminosity function over 10 visual magnitudes and reveal that satellite galaxies dominate the field luminosity function at magnitudes fainter than -17. We find that the luminosity functions of blue and red satellite galaxies show distinct shapes and we present estimates of the stellar mass fraction as a function of halo mass and galaxy type. Finally, using a simple model, we demonstrate that the abundances and the faint-end slopes of blue and red satellite galaxies can be interpreted in terms of their formation history, with two distinct modes separated by some characteristic time.

  2. Calibration and operation of the Faint Object Spectrograph

    NASA Technical Reports Server (NTRS)

    Harms, R.; Beaver, E.; Burbidge, E.; Hier, R.; Allen, R.; Angel, R.; Bartko, F.; Bohlin, R.; Ford, H.; Davidson, A.

    1984-01-01

    The design and basic performance characteristics of the Faint Object Spectrograph (FOS), one of five instruments built for use on the Space Telescope observatory, is summarized briefly. The results of the recently completed instrument-level calibration are presented with special emphasis on issues affecting plans for FOS astronomical observations. Examples include such fundamental characteristics as: limiting magnitudes (system sensitivity and noise figures), spectral coverage and resolution, scattered light properties, and instrumental polarization and modulation efficiencies. Also gated toward intended users, a rather detailed description of FOS operating modes is given. The discussion begins with the difficulties anticipated during target acquisition and their hoped-for resolution. Both the 'normal' spectroscopic operating modes of the FOS and its 'exotic' features (e.g. spectropolarimetric, time-tagged, and time-resolved modes) are presented. The paper concludes with an overview of the activities to assure proper alignment and operation of the FOS within the entire Space Telescope system (orbital and ground-based).

  3. Very faint X-ray binaries with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Armas Padilla, M.

    2016-06-01

    A population of very faint X-ray binaries has been discovered in the last years thanks to the improvement in sensitivity and resolution of the new generations of X-ray missions. These systems show anomalously low luminosities, below 10^{36} ergs/sec, challenging our understanding of accretion physics and binary evolution models, and thereby opening new windows for both observational and theoretical work on accretion onto compact objects. XMM-Newton is playing a crucial role in the study of this dim family of objects thanks to its incomparable spectral capabilities at low luminosities. I will review the state-of-the-art of the field and present our XMM results in both black hole and neutron star objects. Finally, I will discuss the possibilities that the new generation of X-ray telescopes offer for this research line.

  4. A sample of Swift/SDSS faint blazars

    NASA Astrophysics Data System (ADS)

    Fraga, Bernardo; Giommi, Paolo; Turriziani, Sara

    2015-12-01

    We aim here to provide a complete sample of faint (fr ≳ 1 mJy, fx ≳ 10-15 erg cm-2 s-1) blazars and blazar candidates serendipitously discovered in deep Swift images centered on Gamma-ray bursts (GRBs). By stacking all available images, we obtain exposures ranging from 104 to more than a million seconds. Since GRBs are thought to explode randomly across the sky, this set of deep fields can be considered as an unbiased survey of ≈ 12 square degrees of extragalactic sky, with sensitivities reaching a few 10-15 erg cm-2 s-1 in the 0.5-2 keV band. We then derive the x-ray Log N Log S and show that, considering that our sample may be contaminated by sources other than blazars, we are in agreement with previous estimations based on data and simulations.

  5. The faint young sun-climate paradox - Continental influences

    NASA Technical Reports Server (NTRS)

    Endal, A. S.; Schatten, K. H.

    1982-01-01

    We examine the various mechanisms which have been proposed to compensate for the climatic effects of a 30% increase in the solar luminosity over the past 4 1/2 billion years. Although atmospheric greenhouse effects have received most attention, other mechanisms may have played a role of comparable importance. In particular, we note that the development of continents during the past 2 1/2 billion years could have had a significant secular effect on the atmosphere-ocean heat transport system. As a result, past climates may have been less susceptible to complete freeze-over. A simple energy balance model is used to demonstrate the magnitude of this effect. Because the CO2 greenhouse effect is not the only means of compensating for solar evolution, the faint-young-sun problem should not be used to infer past levels of atmospheric CO2.

  6. Do the enigmatic ``Infrared-Faint Radio Sources'' include pulsars?

    NASA Astrophysics Data System (ADS)

    Hobbs, George; Middelberg, Enno; Norris, Ray; Keith, Michael; Mao, Minnie; Champion, David

    2009-04-01

    The Australia Telescope Large Area Survey (ATLAS) team have surveyed seven square degrees of sky at 1.4GHz. During processing some unexpected infrared-faint radio sources (IFRS sources) were discovered. The nature of these sources is not understood, but it is possible that some of these sources may be pulsars within our own galaxy. We propose to observe the IFRS sources with steep spectral indices using standard search techniques to determine whether or not they are pulsars. A pulsar detection would 1) remove a subset of the IFRS sources from the ATLAS sample so they would not need to be observed with large optical/IR telescopes to find their hosts and 2) be intrinsically interesting as the pulsar would be a millisecond pulsar and/or have an extreme spatial velocity.

  7. Morphology and astrometry of Infrared-Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Middelberg, Enno; Norris, Ray; Randall, Kate; Mao, Minnie; Hales, Christopher

    2008-10-01

    Infrared-Faint Radio Sources, or IFRS, are an unexpected class of object discovered in the Australia Telescope Large Area Survey, ATLAS. They are compact 1.4GHz radio sources with no visible counterparts in co-located (relatively shallow) Spitzer infrared and optical images. We have detected two of these objects with VLBI, indicating the presence of an AGN. These observations and our ATLAS data indicate that IFRS are extended on scales of arcseconds, and we wish to image their morphologies to obtain clues about their nature. These observations will also help us to select optical counterparts from very deep, and hence crowded, optical images which we have proposed. With these data in hand, we will be able to compare IFRS to known object types and to apply for spectroscopy to obtain their redshifts.

  8. Mass influx obtained from LLLTV observations of faint meteors

    NASA Technical Reports Server (NTRS)

    Naumann, R. J.; Clifton, K. S.

    1972-01-01

    Since the advent of low light level television (LLLTV) systems, it has been recognized that such devices offer the ability to observe meteors as faint as 10th magnitude which allows the extension of optical meteor data to masses as small as 0.0001 grams. The Space Sciences Lab at Marshall Space Flight Center has been actively engaged in such observations using image orthicons and intensified SEC vidicons. The results of these observations are presented along with an interpretation in terms of mass-flux. This interpretation includes the development of a relationship between peak luminosity of a meteor and mass, velocity, and zenith angle that was derived from single body meteor theory and compares favorably with results obtained from the Artificial Program. Also included in the mass flux interpretation is an analysis of the observation response of a LLLTV system to fixed and moving point sources.

  9. Four QSOs found in a survey of faint objects

    NASA Astrophysics Data System (ADS)

    Morton, D. C.; Tritton, K. P.

    1982-02-01

    Four quasars with redshifts z = 0.6185, 0.6267, 0.850, and 1.665 have been found in the central 33.4 arcmin square of the field at 22h.05, -18deg.91 surveyed by Savage and Bolton (1979) and Krug et al. (1980). The first two quasars are separated by 6.8 arcmin and may be associated with groups of faint galaxies. The separation is well within the 20 Mpc or larger dimensions suggested by Oort et al. (1981) for superclusters, and the velocity difference is not unusual if the velocity dispersion is near the upper end of the range of 300-600 km/s

  10. A spectroscopic search for faint secondaries in cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Vande Putte, D.; Smith, Robert Connon; Hawkins, N. A.; Martin, J. S.

    2003-06-01

    The secondary in cataclysmic variables (CVs) is usually detected by cross-correlation of the CV spectrum with that of a K or M dwarf template, to produce a radial velocity curve. Although this method has demonstrated its power, it has its limits in the case of noisy spectra, such as are found when the secondary is faint. A method of coadding spectra, called skew mapping, has been proposed in the past. Gradually, examples of its application are being published; none the less, so far no journal article has described the technique in detail. To answer this need, this paper explores in detail the capabilities of skew mapping when determining the amplitude of the radial velocity for faint secondaries. It demonstrates the power of the method over techniques that are more conventional, when the signal-to-noise ratio is poor. The paper suggests an approach to assessing the quality of results. This leads in the case of the investigated objects to a first tier of results, where we find K2= 127 +/- 23 km s-1 for SY Cnc, K2= 144 +/- 18 km s-1 for RW Sex and K2= 262 +/- 14 km s-1 for UX UMa. These we believe to be the first direct determinations of K2 for these objects. Furthermore, we also obtain K2= 263 +/- 30 km s-1 for RW Tri, close to a skew mapping result obtained elsewhere. In the first three cases, we use these results to derive the mass of the white dwarf companion. A second tier of results includes UU Aqr, EX Hya and LX Ser, for which we propose more tentative values of K2. Clear failures of the method are also discussed (EF Eri, VV Pup and SW Sex).

  11. MEASURING SIZES OF ULTRA-FAINT DWARF GALAXIES

    SciTech Connect

    Munoz, Ricardo R.; Padmanabhan, Nikhil; Geha, Marla

    2012-02-01

    The discovery of ultra-faint dwarf (UFD) galaxies in the halo of the Milky Way extends the faint end of the galaxy luminosity function to a few hundred solar luminosities. This extremely low luminosity regime poses a significant challenge for the photometric characterization of these systems. We present a suite of simulations aimed at understanding how different observational choices related to the properties of a low-luminosity system impact our ability to determine its true structural parameters such as half-light radius and central surface brightness. We focus on estimating half-light radii (on which mass estimates depend linearly) and find that these numbers can have up to 100% uncertainties when relatively shallow photometric surveys, such as the Sloan Digital Sky Survey, are used. Our simulations suggest that to recover structural parameters within 10% or better of their true values: (1) the ratio of the field of view to the half-light radius of the satellite must be greater than three, (2) the total number of stars, including background objects should be larger than 1000, and (3) the central to background stellar density ratio must be higher than 20. If one or more of these criteria are not met, the accuracy of the resulting structural parameters can be significantly compromised. In the context of future surveys such as Large Synoptic Survey Telescope, the latter condition will be closely tied to our ability to remove unresolved background galaxies. Assessing the reliability of measured structural parameters will become increasingly critical as the next generation of deep wide-field surveys detects UFDs beyond the reach of current spectroscopic limits.

  12. a Faint and Lonely Brown Dwarf in the Solar Vicinity

    NASA Astrophysics Data System (ADS)

    1997-04-01

    Discovery of KELU-1 Promises New Insights into Strange Objects Brown Dwarfs are star-like objects which are too small to become real stars, yet too large to be real planets. Their mass is too small to ignite those nuclear processes which are responsible for the large energies and high temperatures of stars, but it is much larger than that of the planets we know in our solar system. Until now, very few Brown Dwarfs have been securely identified as such. Two are members of double-star systems, and a few more are located deep within the Pleiades star cluster. Now, however, Maria Teresa Ruiz of the Astronomy Department at Universidad de Chile (Santiago de Chile), using telescopes at the ESO La Silla observatory, has just discovered one that is all alone and apparently quite near to us. Contrary to the others which are influenced by other objects in their immediate surroundings, this new Brown Dwarf is unaffected and will thus be a perfect object for further investigations that may finally allow us to better understand these very interesting celestial bodies. It has been suggested that Brown Dwarfs may constitute a substantial part of the unseen dark matter in our Galaxy. This discovery may therefore also have important implications for this highly relevant research area. Searching for nearby faint stars The story of this discovery goes back to 1987 when Maria Teresa Ruiz decided to embark upon a long-term search (known as the Calan-ESO proper-motion survey ) for another type of unusual object, the so-called White Dwarfs , i.e. highly evolved, small and rather faint stars. Although they have masses similar to that of the Sun, such stars are no larger than the Earth and are therefore extremely compact. They are particularly interesting, because they most probably represent the future end point of evolution of our Sun, some billions of years from now. For this project, the Chilean astronomer obtained large-field photographic exposures with the 1-m ESO Schmidt telescope at

  13. Red Sky with Red Mesa

    SciTech Connect

    2011-04-14

    The Red Sky/Red Mesa supercomputing platform dramatically reduces the time required to simulate complex fuel models, from 4-6 months to just 4 weeks, allowing researchers to accelerate the pace at which they can address these complex problems. Its speed also reduces the need for laboratory and field testing, allowing for energy reduction far beyond data center walls.

  14. Red Sky with Red Mesa

    ScienceCinema

    None

    2014-06-23

    The Red Sky/Red Mesa supercomputing platform dramatically reduces the time required to simulate complex fuel models, from 4-6 months to just 4 weeks, allowing researchers to accelerate the pace at which they can address these complex problems. Its speed also reduces the need for laboratory and field testing, allowing for energy reduction far beyond data center walls.

  15. Red Capes, Red Herrings, and Red Flags.

    ERIC Educational Resources Information Center

    Fiske, Donald W.

    The argument that the personality structures obtained from retrospective ratings reflect semantic similarity structures has been as provocative as a red cape in the bull ring. High congruence between those two kinds of structures seems well established. What is less clear is how and why those structures differ from that for immediate judgments of…

  16. A white dwarf companion to the main-sequence star 4 Omicron(1) Orionis and the binary hypothesis for the origin of peculiar red giants

    NASA Astrophysics Data System (ADS)

    Ake, Thomas B.; Johnson, Hollis R.

    1988-04-01

    In the course of an investigation with the IUE satellite of the ultraviolet spectra of peculiar red giants, the authors have discovered a white dwarf companion to the MS star 4 ο1Ori. They discuss the reductions performed for the ο1Ori IUE observations, and compare these with field white dwarfs to derive parameters of the white dwarf and the luminosity of the primary. Upper detection limits are derived for hot degenerate companions to four other bright MS stars, HR 363, RS Cnc, ST Her, and OP Her. Combined with the ο1Ori observations, it is argued that the nondetections for these stars are consistent with the statistics of field giant binaries and that either mass-transfer effects are not responsible for the incipient S-star nature of the MS stars, if their abundance peculiarities are recent, or that the MS stars must be older than 106yr.

  17. Serendipitous discovery of the faint solar twin Inti 1

    NASA Astrophysics Data System (ADS)

    Galarza, Jhon Yana; Meléndez, Jorge; Cohen, Judith G.

    2016-04-01

    Context. Solar twins are increasingly the subject of many studies owing to their wide range of applications from testing stellar evolution models to the calibration of fundamental observables; these stars are also of interest because high precision abundances could be achieved that are key to investigating the chemical anomalies imprinted by planet formation. Furthermore, the advent of photometric surveys with large telescopes motivates the identification of faint solar twins in order to set the zero point of fundamental calibrations. Aims: We intend to perform a detailed line-by-line differential analysis to verify whether 2MASS J23263267-0239363 (designated here as Inti 1) is indeed a solar twin. Methods: We determine the atmospheric parameters and differential abundances using high-resolution (R ≈ 50 000), high signal-to-noise (S/N ≈ 110-240 per pixel) Keck/HIRES spectra for our solar twin candidate, the previously known solar twin HD 45184, and the Sun (using reflected light from the asteroid Vesta). Results: For the bright solar twin HD 45184, we found Teff = 5864 ± 9 K, log g = 4.45 ± 0.03 dex, vt = 1.11 ± 0.02 km s-1, and [Fe/H] = 0.04 ± 0.01 dex, which are in good agreement with previous works. Our abundances are in excellent agreement with a recent high-precision work, with an element-to-element scatter of only 0.01 dex. The star Inti 1 has atmospheric parameters Teff = 5837 ± 11 K, log g = 4.42 ± 0.03 dex, vt = 1.04 ± 0.02 km s-1, and [Fe/H] = 0.07 ± 0.01 dex that are higher than solar. The age and mass of the solar twin HD 45184 (3 Gyr and 1.05 M⊙) and the faint solar twin Inti 1 (4 Gyr and 1.04 M⊙) were estimated using isochrones. The differential analysis shows that HD 45184 presents an abundance pattern that is similar to typical nearby solar twins; this means this star has an enhanced refractory relative to volatile elements, while Inti 1 has an abundance pattern closer to solar, albeit somewhat enhanced in refractories. The abundance

  18. Serendipitous discovery of the faint solar twin Inti 1

    NASA Astrophysics Data System (ADS)

    Galarza, Jhon Yana; Meléndez, Jorge; Cohen, Judith G.

    2016-05-01

    Context. Solar twins are increasingly the subject of many studies owing to their wide range of applications from testing stellar evolution models to the calibration of fundamental observables; these stars are also of interest because high precision abundances could be achieved that are key to investigating the chemical anomalies imprinted by planet formation. Furthermore, the advent of photometric surveys with large telescopes motivates the identification of faint solar twins in order to set the zero point of fundamental calibrations. Aims: We intend to perform a detailed line-by-line differential analysis to verify whether 2MASS J23263267-0239363 (designated here as Inti 1) is indeed a solar twin. Methods: We determine the atmospheric parameters and differential abundances using high-resolution (R ≈ 50 000), high signal-to-noise (S/N ≈ 110-240 per pixel) Keck/HIRES spectra for our solar twin candidate, the previously known solar twin HD 45184, and the Sun (using reflected light from the asteroid Vesta). Results: For the bright solar twin HD 45184, we found Teff = 5864 ± 9 K, log g = 4.45 ± 0.03 dex, vt = 1.11 ± 0.02 km s-1, and [Fe/H] = 0.04 ± 0.01 dex, which are in good agreement with previous works. Our abundances are in excellent agreement with a recent high-precision work, with an element-to-element scatter of only 0.01 dex. The star Inti 1 has atmospheric parameters Teff = 5837 ± 11 K, log g = 4.42 ± 0.03 dex, vt = 1.04 ± 0.02 km s-1, and [Fe/H] = 0.07 ± 0.01 dex that are higher than solar. The age and mass of the solar twin HD 45184 (3 Gyr and 1.05 M⊙) and the faint solar twin Inti 1 (4 Gyr and 1.04 M⊙) were estimated using isochrones. The differential analysis shows that HD 45184 presents an abundance pattern that is similar to typical nearby solar twins; this means this star has an enhanced refractory relative to volatile elements, while Inti 1 has an abundance pattern closer to solar, albeit somewhat enhanced in refractories. The abundance

  19. Faint Blue Galaxies and the Epoch of Dwarf Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Babul, Arif; Ferguson, Henry C.

    1996-02-01

    Several independent lines of reasoning, both theoretical and observational, suggest that the very faint (B ≳ 24) galaxies seen in deep images of the sky are small low-mass galaxies that experienced a short starburst at redshifts 0.5 ≲ z ≲ 1 and have since faded into low-luminosity, low surface brightness (LSB) objects. We examine this hypothesis in detail in order to determine whether a model incorporating such dwarfs can account for the observed wavelength-dependent number counts, as well as redshift, color, and size distributions. Low-mass galaxies generically arise in large numbers in hierarchical clustering scenarios with realistic initial conditions. Generally, these galaxies are expected to form at high redshifts. Babul & Rees have argued that the formation epoch of these galaxies is, in fact, delayed until z ≲ 1 due to the photoionization of the gas by the metagalactic UV radiation at high redshifts. We combine these two elements, along with simple heuristic assumptions regarding star formation histories and efficiency, to construct our bursting dwarf model. The slope and the normalization of the mass function of the dwarf galaxies are derived from the initial conditions and are not adjusted to fit the data. We further augment the model with a phenomenological prescription for the formation and evolution of the locally observed population of galaxies (E, S0, Sab, Sbc, and Sdm types). We use spectral synthesis and Monte Carlo methods to generate realistic model galaxy catalogs for comparison with observations. We find that for reasonable choices of the star formation histories for the dwarf galaxies, the model results are in very good agreement with the results of the deep galaxy surveys. Such a dwarf-dominated model is also qualitatively supported by recent studies of faint galaxy gravitational lensing and clustering, by galaxy size distributions measured with the Hubble Space Telescope, and by the evidence for very modest evolution in regular galaxy

  20. The cDNA Sequence of Two Hemocyanin Subunits from Red Swamp Crayfish Procambarus clarkii and their Responses to White Spot Syndrome Virus Infection.

    PubMed

    Zeng, Yong

    2016-03-01

    Hemocyanin, the respiratory protein of crustaceans, participates in the innate immune defense in these organisms. We cloned two hemocyanin subunit genes (PcHc1 and PcHc2), by using a degenerate primer PCR and rapid amplification of cDNA ends (RACE) approach, from the hepatopancreas of red swamp crayfish Procambarus clarkii. The transcripts of these two subunits were only detected in the hepatopancreas by reverse transcriptase quantitative PCR (RT-qPCR) analysis. The neighbor-joining and maximum parsimony phylogenetic analyses indicated that PcHc2 associated with a clade belong to the α-type hemocyanins and PcHc1 associated with another clade belonging to the β-type hemocyanins. The data obtained from the RT-qPCR indicated that the mRNA expression levels of these subunit genes followed almost the same regulation pattern in the crayfish challenged with white spot syndrome virus (WSSV). The fluctuation of mRNA expression levels of these two subunits after the WSSV challenge indicated that both of them may participate in the antiviral immune response of crayfish. Received April 12, 2015; accepted November 22, 2015. PMID:26949985

  1. Identification and Analysis of Red Sea Mangrove (Avicennia marina) microRNAs by High-Throughput Sequencing and Their Association with Stress Responses

    PubMed Central

    Khraiwesh, Basel; Pugalenthi, Ganesan; Fedoroff, Nina V.

    2013-01-01

    Although RNA silencing has been studied primarily in model plants, advances in high-throughput sequencing technologies have enabled profiling of the small RNA components of many more plant species, providing insights into the ubiquity and conservatism of some miRNA-based regulatory mechanisms. Small RNAs of 20 to 24 nucleotides (nt) are important regulators of gene transcript levels by either transcriptional or by posttranscriptional gene silencing, contributing to genome maintenance and controlling a variety of developmental and physiological processes. Here, we used deep sequencing and molecular methods to create an inventory of the small RNAs in the mangrove species, Avicennia marina. We identified 26 novel mangrove miRNAs and 193 conserved miRNAs belonging to 36 families. We determined that 2 of the novel miRNAs were produced from known miRNA precursors and 4 were likely to be species-specific by the criterion that we found no homologs in other plant species. We used qRT-PCR to analyze the expression of miRNAs and their target genes in different tissue sets and some demonstrated tissue-specific expression. Furthermore, we predicted potential targets of these putative miRNAs based on a sequence homology and experimentally validated through endonucleolytic cleavage assays. Our results suggested that expression profiles of miRNAs and their predicted targets could be useful in exploring the significance of the conservation patterns of plants, particularly in response to abiotic stress. Because of their well-developed abilities in this regard, mangroves and other extremophiles are excellent models for such exploration. PMID:23593307

  2. Identification and analysis of red sea mangrove (Avicennia marina) microRNAs by high-throughput sequencing and their association with stress responses.

    PubMed

    Khraiwesh, Basel; Pugalenthi, Ganesan; Fedoroff, Nina V

    2013-01-01

    Although RNA silencing has been studied primarily in model plants, advances in high-throughput sequencing technologies have enabled profiling of the small RNA components of many more plant species, providing insights into the ubiquity and conservatism of some miRNA-based regulatory mechanisms. Small RNAs of 20 to 24 nucleotides (nt) are important regulators of gene transcript levels by either transcriptional or by posttranscriptional gene silencing, contributing to genome maintenance and controlling a variety of developmental and physiological processes. Here, we used deep sequencing and molecular methods to create an inventory of the small RNAs in the mangrove species, Avicennia marina. We identified 26 novel mangrove miRNAs and 193 conserved miRNAs belonging to 36 families. We determined that 2 of the novel miRNAs were produced from known miRNA precursors and 4 were likely to be species-specific by the criterion that we found no homologs in other plant species. We used qRT-PCR to analyze the expression of miRNAs and their target genes in different tissue sets and some demonstrated tissue-specific expression. Furthermore, we predicted potential targets of these putative miRNAs based on a sequence homology and experimentally validated through endonucleolytic cleavage assays. Our results suggested that expression profiles of miRNAs and their predicted targets could be useful in exploring the significance of the conservation patterns of plants, particularly in response to abiotic stress. Because of their well-developed abilities in this regard, mangroves and other extremophiles are excellent models for such exploration. PMID:23593307

  3. Results of a search for faint galaxies in voids.

    NASA Astrophysics Data System (ADS)

    Kuhn, B.; Hopp, U.; Elsaesser, H.

    1997-02-01

    We present the results of a search for intrinsically faint galaxies towards three regions with known voids and the Hercules supercluster. The intention was to identify galaxies of low luminosity in order to find possibly a galaxy population in the voids. Within these selected fields we increased the range of observations in comparison with the recent large field surveys which revealed the non-uniform spatial distribution of galaxies. The limiting magnitude was raised by about 5mag, the limiting surface brightness by 2mag/sq.arcsec, and the limiting diameter reduced to less than 1/3. The individual observational data of our sample are published in the previous PaperI (Hopp et al. 1995) which describes our search strategy and contains B and R magnitudes, apparent diameters, redshifts and galaxy types of about 200 newly identified objects. Their luminosity distribution demonstrates a relatively high percentage of dwarfish galaxies. As the essential result of our survey we have to point out that no clear indication of a void-population was found. The majority of our objects lie outside voids in regions where the already known galaxies are concentrated. Some are located in the middle or near the edges of voids. They appear to be rather isolated, their distances to the nearest neighbour are quite large. Only few of our objects seem to be real void galaxies. Even in the three nearest and rather well defined voids we do not find any hitherto unknown galaxy.

  4. Helium shells and faint emission lines from slitless flash spectra

    NASA Astrophysics Data System (ADS)

    Bazin, Cyril; Koutchmy, Serge

    2013-05-01

    At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence.

  5. Luminosity Function of Faint Globular Clusters in M87

    SciTech Connect

    Waters, Christopher Z.; Zepf, Stephen E.; Lauer, Tod R.; Baltz, Edward A.; Silk, Joseph; /Oxford U.

    2006-07-14

    We present the luminosity function to very faint magnitudes for the globular clusters in M87, based on a 30 orbit Hubble Space Telescope (HST) WFPC2 imaging program. The very deep images and corresponding improved false source rejection allow us to probe the mass function further beyond the turnover than has been done before. We compare our luminosity function to those that have been observed in the past, and confirm the similarity of the turnover luminosity between M87 and the Milky Way. We also find with high statistical significance that the M87 luminosity function is broader than that of the Milky Way. We discuss how determining the mass function of the cluster system to low masses can constrain theoretical models of the dynamical evolution of globular cluster systems. Our mass function is consistent with the dependence of mass loss on the initial cluster mass given by classical evaporation, and somewhat inconsistent with newer proposals that have a shallower mass dependence. In addition, the rate of mass loss is consistent with standard evaporation models, and not with the much higher rates proposed by some recent studies of very young cluster systems. We also find that the mass-size relation has very little slope, indicating that there is almost no increase in the size of a cluster with increasing mass.

  6. VLBI observations of Infrared-Faint Radio Sources

    NASA Astrophysics Data System (ADS)

    Middelberg, Enno; Phillips, Chris; Norris, Ray; Tingay, Steven

    2006-10-01

    We propose to observe a small sample of radio sources from the ATLAS project (ATLAS = Australia Telescope Large Area Survey) with the LBA, to determine their compactness and map their structures. The sample consists of three radio sources with no counterpart in the co-located SWIRE survey (3.6 um to 160 um), carried out with the Spitzer Space Telescope. This rare class of sources, dubbed Infrared-Faint Radio Sources, or IFRS, is inconsistent with current galaxy evolution models. VLBI observations are an essential way to obtain further clues on what these objects are and why they are hidden from infrared observations: we will map their structure to test whether they resemble core-jet or double-lobed morphologies, and we will measure the flux densities on long baselines, to determine their compactness. Previous snapshot-style LBA observations of two other IFRS yielded no detections, hence we propose to use disk-based recording with 512 Mbps where possible, for highest sensitivity. With the observations proposed here, we will increase the number of VLBI-observed IFRS from two to five, soon allowing us to draw general conclusions about this intriguing new class of objects.

  7. Helium shells and faint emission lines from slitless flash spectra

    PubMed Central

    Bazin, Cyril; Koutchmy, Serge

    2013-01-01

    At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence. PMID:25685435

  8. THE PRIMEVAL POPULATIONS OF THE ULTRA-FAINT DWARF GALAXIES

    SciTech Connect

    Brown, Thomas M.; Tumlinson, Jason; Kalirai, Jason S.; Avila, Roberto J.; Ferguson, Henry C. E-mail: tumlinson@stsci.edu E-mail: avila@stsci.edu; and others

    2012-07-01

    We present new constraints on the star formation histories of the ultra-faint dwarf (UFD) galaxies, using deep photometry obtained with the Hubble Space Telescope (HST). A galaxy class recently discovered in the Sloan Digital Sky Survey, the UFDs appear to be an extension of the classical dwarf spheroidals to low luminosities, offering a new front in efforts to understand the missing satellite problem. They are the least luminous, most dark-matter-dominated, and least chemically evolved galaxies known. Our HST survey of six UFDs seeks to determine if these galaxies are true fossils from the early universe. We present here the preliminary analysis of three UFD galaxies: Hercules, Leo IV, and Ursa Major I. Classical dwarf spheroidals of the Local Group exhibit extended star formation histories, but these three Milky Way satellites are at least as old as the ancient globular cluster M92, with no evidence for intermediate-age populations. Their ages also appear to be synchronized to within {approx}1 Gyr of each other, as might be expected if their star formation was truncated by a global event, such as reionization.

  9. No climate paradox under the faint early Sun.

    PubMed

    Rosing, Minik T; Bird, Dennis K; Sleep, Norman H; Bjerrum, Christian J

    2010-04-01

    Environmental niches in which life first emerged and later evolved on the Earth have undergone dramatic changes in response to evolving tectonic/geochemical cycles and to biologic interventions, as well as increases in the Sun's luminosity of about 25 to 30 per cent over the Earth's history. It has been inferred that the greenhouse effect of atmospheric CO(2) and/or CH(4) compensated for the lower solar luminosity and dictated an Archaean climate in which liquid water was stable in the hydrosphere. Here we demonstrate, however, that the mineralogy of Archaean sediments, particularly the ubiquitous presence of mixed-valence Fe(II-III) oxides (magnetite) in banded iron formations is inconsistent with such high concentrations of greenhouse gases and the metabolic constraints of extant methanogens. Prompted by this, and the absence of geologic evidence for very high greenhouse-gas concentrations, we hypothesize that a lower albedo on the Earth, owing to considerably less continental area and to the lack of biologically induced cloud condensation nuclei, made an important contribution to moderating surface temperature in the Archaean eon. Our model calculations suggest that the lower albedo of the early Earth provided environmental conditions above the freezing point of water, thus alleviating the need for extreme greenhouse-gas concentrations to satisfy the faint early Sun paradox. PMID:20360739

  10. ARE THE ULTRA-FAINT DWARF GALAXIES JUST CUSPS?

    SciTech Connect

    Zolotov, Adi; Hogg, David W.; Willman, Beth

    2011-01-20

    We develop a technique to investigate the possibility that some of the recently discovered ultra-faint dwarf satellites of the Milky Way might be cusp caustics rather than gravitationally self-bound systems. Such cusps can form when a stream of stars folds, creating a region where the projected two-dimensional surface density is enhanced. In this work, we construct a Poisson maximum likelihood test to compare the cusp and exponential models of any substructure on an equal footing. We apply the test to the Hercules dwarf (d {approx} 113 kpc, M{sub V} {approx} -6.2, e {approx} 0.67). The flattened exponential model is strongly favored over the cusp model in the case of Hercules, ruling out at high confidence that Hercules is a cusp catastrophe. This test can be applied to any of the Milky Way dwarfs, and more generally to the entire stellar halo population, to search for the cusp catastrophes that might be expected in an accreted stellar halo.

  11. Helium shells and faint emission lines from slitless flash spectra.

    PubMed

    Bazin, Cyril; Koutchmy, Serge

    2013-05-01

    At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence. PMID:25685435

  12. MEASURING X-RAY VARIABILITY IN FAINT/SPARSELY SAMPLED ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Allevato, V.; Paolillo, M.; Papadakis, I.; Pinto, C.

    2013-07-01

    We study the statistical properties of the normalized excess variance of variability process characterized by a ''red-noise'' power spectral density (PSD), as in the case of active galactic nuclei (AGNs). We perform Monte Carlo simulations of light curves, assuming both a continuous and a sparse sampling pattern and various signal-to-noise ratios (S/Ns). We show that the normalized excess variance is a biased estimate of the variance even in the case of continuously sampled light curves. The bias depends on the PSD slope and on the sampling pattern, but not on the S/N. We provide a simple formula to account for the bias, which yields unbiased estimates with an accuracy better than 15%. We show that the normalized excess variance estimates based on single light curves (especially for sparse sampling and S/N < 3) are highly uncertain (even if corrected for bias) and we propose instead the use of an ''ensemble estimate'', based on multiple light curves of the same object, or on the use of light curves of many objects. These estimates have symmetric distributions, known errors, and can also be corrected for biases. We use our results to estimate the ability to measure the intrinsic source variability in current data, and show that they could also be useful in the planning of the observing strategy of future surveys such as those provided by X-ray missions studying distant and/or faint AGN populations and, more in general, in the estimation of the variability amplitude of sources that will result from future surveys such as Pan-STARRS and LSST.

  13. THE DISTRIBUTION OF ALPHA ELEMENTS IN ULTRA-FAINT DWARF GALAXIES

    SciTech Connect

    Vargas, Luis C.; Geha, Marla; Kirby, Evan N.; Simon, Joshua D.

    2013-04-20

    The Milky Way ultra-faint dwarf (UFD) galaxies contain some of the oldest, most metal-poor stars in the universe. We present [Mg/Fe], [Si/Fe], [Ca/Fe], [Ti/Fe], and mean [{alpha}/Fe] abundance ratios for 61 individual red giant branch stars across eight UFDs. This is the largest sample of alpha abundances published to date in galaxies with absolute magnitudes M{sub V} > -8, including the first measurements for Segue 1, Canes Venatici II, Ursa Major I, and Leo T. Abundances were determined via medium-resolution Keck/DEIMOS spectroscopy and spectral synthesis. The sample spans the metallicity range -3.4 <[Fe/H] < -1.1. With the possible exception of Segue 1 and Ursa Major II, the individual UFDs show on average lower [{alpha}/Fe] at higher metallicities, consistent with enrichment from Type Ia supernovae. Thus, even the faintest galaxies have undergone at least a limited level of chemical self-enrichment. Together with recent photometric studies, this suggests that star formation in the UFDs was not a single burst, but instead lasted at least as much as the minimum time delay of the onset of Type Ia supernovae ({approx}100 Myr) and less than {approx}2 Gyr. We further show that the combined population of UFDs has an [{alpha}/Fe] abundance pattern that is inconsistent with a flat, Galactic halo-like alpha abundance trend, and is also qualitatively different from that of the more luminous CVn I dSph, which does show a hint of a plateau at very low [Fe/H].

  14. Faint photoelectric photometric standard star sequences. Final report, 1 January 1982-30 June 1988

    SciTech Connect

    Landolt, A.

    1988-07-15

    The primary purpose of the research funded via AFOSR Grant No. 82-0192 was to establish highly accurate standard stars covering a wide range both in brightness and color around the celestial sphere. The availability of such standard stars would enable anyone to determine the brightness or color of any object projected against the sky from land, the air, or in space. Other secondary projects also were undertaken as circumstances warrented. This document outlines the overall program, including the data acquisition, analysis, and results.

  15. On the Morphology of the HST Faint Galaxies

    NASA Astrophysics Data System (ADS)

    Giavalisco, Mauro; Livio, Mario; Bohlin, Ralph C.; Macchetto, F. Duccio; Stecher, Theodore P.

    1996-08-01

    Deep imaging with the Hubble Space Telescope (HST) has revealed a population of rapidly evolving galaxies, which account for < 50% of the total counts at I <~ 22.5, are well distinct from the passively evolving normal ellipticals and spirals, and have morphologies that elude the traditional Hubble classification scheme. This classification has been derived from the morphological properties of local galaxies observed at optical wavelengths. Since galaxy morphology is a function of the wavelength and of the localization and intensity of the star-formation activity, the appearance of galaxies at large redshifts is subject to k- correction and evolutionary effects of the stellar populations, even if the underlying dynamics does not change significantly. In addition, the strong dependence of the surface brightness on redshift as σ ~(1 +z)^-4^ implies that the observed morphology of distant galaxies is also affected by the limiting surface brightness that can be reached. This paper shows how local galaxies observed at UV wavelengths with the Ultraviolet Imaging Telescope (UIT) would appear to HST if placed at cosmological distances, with the UV light redshifted to the optical wavelengths. The simulated distant galaxies have morphologies that are of later type or more irregular than their local (optical) counterparts, and some are in qualitative agreement with those revealed by the faint HST surveys, suggesting that dynamical evolution has played a minor role in the evolution of the majority of the galaxies over a large fraction of the Hubble time. However, the dependence of galaxy morphology on the star-formation activity and on the wavelength must be properly understood before any conclusion on the overall morphological evolution of galaxies can be derived.

  16. Faint Object Camera imaging and spectroscopy of NGC 4151

    NASA Technical Reports Server (NTRS)

    Boksenberg, A.; Catchpole, R. M.; Macchetto, F.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Crane, P.; Deharveng, J. M.; Disney, M. J.; Jakobsen, P.

    1995-01-01

    We describe ultraviolet and optical imaging and spectroscopy within the central few arcseconds of the Seyfert galaxy NGC 4151, obtained with the Faint Object Camera on the Hubble Space Telescope. A narrowband image including (O III) lambda(5007) shows a bright nucleus centered on a complex biconical structure having apparent opening angle approximately 65 deg and axis at a position angle along 65 deg-245 deg; images in bands including Lyman-alpha and C IV lambda(1550) and in the optical continuum near 5500 A, show only the bright nucleus. In an off-nuclear optical long-slit spectrum we find a high and a low radial velocity component within the narrow emission lines. We identify the low-velocity component with the bright, extended, knotty structure within the cones, and the high-velocity component with more confined diffuse emission. Also present are strong continuum emission and broad Balmer emission line components, which we attribute to the extended point spread function arising from the intense nuclear emission. Adopting the geometry pointed out by Pedlar et al. (1993) to explain the observed misalignment of the radio jets and the main optical structure we model an ionizing radiation bicone, originating within a galactic disk, with apex at the active nucleus and axis centered on the extended radio jets. We confirm that through density bounding the gross spatial structure of the emission line region can be reproduced with a wide opening angle that includes the line of sight, consistent with the presence of a simple opaque torus allowing direct view of the nucleus. In particular, our modelling reproduces the observed decrease in position angle with distance from the nucleus, progressing initially from the direction of the extended radio jet, through our optical structure, and on to the extended narrow-line region. We explore the kinematics of the narrow-line low- and high-velocity components on the basis of our spectroscopy and adopted model structure.

  17. The radio properties of infrared-faint radio sources

    NASA Astrophysics Data System (ADS)

    Middelberg, E.; Norris, R. P.; Hales, C. A.; Seymour, N.; Johnston-Hollitt, M.; Huynh, M. T.; Lenc, E.; Mao, M. Y.

    2011-02-01

    Context. Infrared-faint radio sources (IFRS) are objects that have flux densities of several mJy at 1.4 GHz, but that are invisible at 3.6 μm when using sensitive Spitzer observations with μJy sensitivities. Their nature is unclear and difficult to investigate since they are only visible in the radio. Aims: High-resolution radio images and comprehensive spectral coverage can yield constraints on the emission mechanisms of IFRS and can give hints to similarities with known objects. Methods: We imaged a sample of 17 IFRS at 4.8 GHz and 8.6 GHz with the Australia Telescope Compact Array to determine the structures on arcsecond scales. We added radio data from other observing projects and from the literature to obtain broad-band radio spectra. Results: We find that the sources in our sample are either resolved out at the higher frequencies or are compact at resolutions of a few arcsec, which implies that they are smaller than a typical galaxy. The spectra of IFRS are remarkably steep, with a median spectral index of -1.4 and a prominent lack of spectral indices larger than -0.7. We also find that, given the IR non-detections, the ratio of 1.4 GHz flux density to 3.6 μm flux density is very high, and this puts them into the same regime as high-redshift radio galaxies. Conclusions: The evidence that IFRS are predominantly high-redshift sources driven by active galactic nuclei (AGN) is strong, even though not all IFRS may be caused by the same phenomenon. Compared to the rare and painstakingly collected high-redshift radio galaxies, IFRS appear to be much more abundant, but less luminous, AGN-driven galaxies at similar cosmological distances.

  18. Faint Object Spectrograph Instrument Handbook v. 6.0

    NASA Astrophysics Data System (ADS)

    Keyes, C. D.; et al.

    1995-06-01

    This Handbook describes The Faint Object Spectrograph (FOS) and its use for Cycle 6 of the Hubble Space Telescope General Observer program. Many presentations have been updated from previous versions, especially those pertaining to target acquisition, brightness limits, and in- strumental sensitivities needed for exposure and S/N calculations. This Handbook draws upon dis- cussions from earlier versions of the Handbook, notably the Version 1.0 FOS Instrument Handbook (Ford 1985), the Supplement to the Version 1.0 Instrument Handbook (Hartig 1989), and the Version 5.0 Handbook (Kinney, 1994). Only the current document should be used for Cy- cle 6. The detectors are described in detail by Harms et al (1979) and Harms (1982). This version of the FOS Instrument Handbook is for the post-COSTAR refurbished tele- scope. The change in focal length introduced by the addition of COSTAR affects the aperture sizes as projected on the sky. However, the pre-COSTAR aperture designations used in the Remote Pro- posal Submission System, version 2 (RPS2) and in the Project Data Base (PDB) have not been changed. Apertures are referred to throughout this document by their size followed in parentheses by their RPS2 exposure level designation (in Courier typeface). Indeed, all RPS2 desig- nations, which are used for proposal preparation, will be denoted in Courier typeface in this Hand- book. For example, the largest circular aperture is referred to as the 0.9'' (1.0) aperture, while the smallest paired apertures are referred to as the 0.09'' paired (0.1-PAIR)apertures.

  19. Astrometric Follow-Up of Faint Near Earth Objects

    NASA Technical Reports Server (NTRS)

    Morgan, T. (Technical Monitor); Spahr, Timothy

    2004-01-01

    The observing program at Mt. Hopkins using the 48" reflector and funded by the Near- Earth Object Observation Program continues to excel. As in the past, all requested observing time was granted. Minor improvements continue to be made. For example, the telescope is set up to track and non-sidereal rates. This allows the user to track on the target object, rather than relying exclusively on the shift- and-stack technique. Other improvements made by the staff include automatic focus routines, automatic seeing-measurement routines, and improvement in dome seeing and mirror stabilization. The net result is better focus, better seeing, and the ability to expose longer in order to acquire the faintest and most important objects. During the proposal period, this program ranked again very high worldwide in terms of faint Near Earth Objects observed. During this latest proposal cycle, fewer objects were observed than previous cycles, but this was due to the strict targeting of only the faintest observable objects. The follow-up programs of observatory codes 926 (led by P. Holvorcem) and 291 (led by Dr. B. McMillan) have greatly increased their capacity, and as a result less bright objects are in urgent need of follow-up than in years past. Even with this new object selection and additional competition, code 696 still ranked second to code 291 in terms of objects observed fainter than V = 20. Minimal scripting is now in place to allow the telescope to run autonomously for 30-45 minutes at a time.

  20. Genetic Basis for Red Coloration in Birds.

    PubMed

    Lopes, Ricardo J; Johnson, James D; Toomey, Matthew B; Ferreira, Mafalda S; Araujo, Pedro M; Melo-Ferreira, José; Andersson, Leif; Hill, Geoffrey E; Corbo, Joseph C; Carneiro, Miguel

    2016-06-01

    The yellow and red feather pigmentation of many bird species [1] plays pivotal roles in social signaling and mate choice [2, 3]. To produce red pigments, birds ingest yellow carotenoids and endogenously convert them into red ketocarotenoids via an oxidation reaction catalyzed by a previously unknown ketolase [4-6]. We investigated the genetic basis for red coloration in birds using whole-genome sequencing of red siskins (Spinus cucullata), common canaries (Serinus canaria), and "red factor" canaries, which are the hybrid product of crossing red siskins with common canaries [7]. We identified two genomic regions introgressed from red siskins into red factor canaries that are required for red coloration. One of these regions contains a gene encoding a cytochrome P450 enzyme, CYP2J19. Transcriptome analysis demonstrates that CYP2J19 is significantly upregulated in the skin and liver of red factor canaries, strongly implicating CYP2J19 as the ketolase that mediates red coloration in birds. Interestingly, a second introgressed region required for red feathers resides within the epidermal differentiation complex, a cluster of genes involved in development of the integument. Lastly, we present evidence that CYP2J19 is involved in ketocarotenoid formation in the retina. The discovery of the carotenoid ketolase has important implications for understanding sensory function and signaling mediated by carotenoid pigmentation. PMID:27212400

  1. Why Are Rapidly Rotating M Dwarfs in the Pleiades so (Infra)red? New Period Measurements Confirm Rotation-dependent Color Offsets From the Cluster Sequence

    NASA Astrophysics Data System (ADS)

    Covey, Kevin R.; Agüeros, Marcel A.; Law, Nicholas M.; Liu, Jiyu; Ahmadi, Aida; Laher, Russ; Levitan, David; Sesar, Branimir; Surace, Jason

    2016-05-01

    Stellar rotation periods (P rot) measured in open clusters have proved to be extremely useful for studying stars’ angular momentum content and rotationally driven magnetic activity, which are both age- and mass-dependent processes. While P rot measurements have been obtained for hundreds of solar-mass members of the Pleiades, measurements exist for only a few low-mass (<0.5 M ⊙) members of this key laboratory for stellar evolution theory. To fill this gap, we report P rot for 132 low-mass Pleiades members (including nearly 100 with M ≤ 0.45 M ⊙), measured from photometric monitoring of the cluster conducted by the Palomar Transient Factory in late 2011 and early 2012. These periods extend the portrait of stellar rotation at 125 Myr to the lowest-mass stars and re-establish the Pleiades as a key benchmark for models of the transport and evolution of stellar angular momentum. Combining our new P rot with precise BVIJHK photometry reported by Stauffer et al. and Kamai et al., we investigate known anomalies in the photometric properties of K and M Pleiades members. We confirm the correlation detected by Kamai et al. between a star's P rot and position relative to the main sequence in the cluster's color–magnitude diagram. We find that rapid rotators have redder (V ‑ K) colors than slower rotators at the same V, indicating that rapid and slow rotators have different binary frequencies and/or photospheric properties. We find no difference in the photometric amplitudes of rapid and slow rotators, indicating that asymmetries in the longitudinal distribution of starspots do not scale grossly with rotation rate.

  2. Image Stacking Method Application for Low Earth Orbit Faint Objects

    NASA Astrophysics Data System (ADS)

    Tagawa, M.; Matsumoto, H.; Yanagisawa, T.; Kurosaki, H.; Oda, H.; Kitazawa, Y.; Hanada, T.

    2013-09-01

    Space situational awareness is one of the most important actions for safe and sustainable space development and its utilization. Tracking and maintaining debris catalog are the basis of the actions. Current minimum size of objects in the catalog that routinely tracked and updated is approximately 10 cm in the Low Earth Orbit region. This paper proposes collaborative observation of space-based sensors and ground facilities to improve tracking capability in low Earth orbit. This observation geometry based on role-sharing idea. A space-based sensor has advantage in sensitivity and observation opportunity however, it has disadvantages in periodic observation which is essential for catalog maintenance. On the other hand, a ground facility is inferior to space-based sensors in sensitivity however; observation network composed of facilities has an advantage in periodic observation. Whole observation geometry is defined as follows; 1) space-based sensors conduct initial orbit estimation for a target 2) ground facility network tracks the target based on estimated orbit 3) the network observes the target periodically and updates its orbit information. The second phase of whole geometry is based on image stacking method developed by the Japan aerospace exploration agency and this method is verified for objects in geostationary orbit. This method enables to detect object smaller than a nominal size limitation by stacking faint light spot along archived time-series frames. The principle of this method is prediction and searching target's motion on the images. It is almost impossible to apply the method to objects in Low Earth Orbit without proper orbit information because Low Earth Orbit objects have varied orbital characteristics. This paper discusses whether or not initial orbit estimation results given by space-based sensors have enough accuracy to apply image stacking method to Low Earth Orbit objects. Ground-based observation procedure is assumed as being composed of

  3. Spectrum from Faint Galaxy IRAS F00183-7111

    NASA Technical Reports Server (NTRS)

    2003-01-01

    NASA's Spitzer Space Telescope has detected the building blocks of life in the distant universe, albeit in a violent milieu. Training its powerful infrared eye on a faint object located at a distance of 3.2 billion light-years, Spitzer has observed the presence of water and organic molecules in the galaxy IRAS F00183-7111. With an active galactic nucleus, this is one of the most luminous galaxies in the universe, rivaling the energy output of a quasar. Because it is heavily obscured by dust (see visible-light image in the inset), most of its luminosity is radiated at infrared wavelengths.

    The infrared spectrograph instrument onboard Spitzer breaks light into its constituent colors, much as a prism does for visible light. The image shows a low-resolution spectrum of the galaxy obtained by the spectrograph at wavelengths between 4 and 20 microns. Spectra are graphical representations of a celestial object's unique blend of light. Characteristic patterns, or fingerprints, within the spectra allow astronomers to identify the object's chemical composition and to determine such physical properties as temperature and density.

    The broad depression in the center of the spectrum denotes the presence of silicates (chemically similar to beach sand) in the galaxy. An emission peak within the bottom of the trough is the chemical signature for molecular hydrogen. The hydrocarbons (orange) are organic molecules comprised of carbon and hydrogen, two of the most common elements on Earth. Since it has taken more than three billion years for the light from the galaxy to reach Earth, it is intriguing to note the presence of organics in a distant galaxy at a time when life is thought to have started forming on our home planet.

    Additional features in the spectrum reveal the presence of water ice (blue), carbon dioxide ice (green) and carbon monoxide (purple) in both gas and solid forms. The magenta peak corresponds to singly ionized neon gas, a spectral line often used by

  4. Time series photometry of faint cataclysmic variables with a CCD

    NASA Astrophysics Data System (ADS)

    Abbott, Timothy Mark Cameron

    1992-08-01

    I describe a new hardware and software environment for the practice of time-series stellar photometry with the CCD systems available at McDonald Observatory. This instrument runs suitable CCD's in frame transfer mode and permits windowing on the CCD image to maximize the duty cycle of the photometer. Light curves may be extracted and analyzed in real time at the telescope and image data are stored for later, more thorough analysis. I describe a star tracking algorithm, which is optimized for a timeseries of images of the same stellar field. I explore the extraction of stellar brightness measures from these images using circular software apertures and develop a complete description of the noise properties of this technique. I show that scintillation and pixelization noise have a significant effect on high quality observations. I demonstrate that optimal sampling and profile fitting techniques are unnecessarily complex or detrimental methods of obtaining stellar brightness measures under conditions commonly encountered in timeseries CCD photometry. I compare CCD's and photomultiplier tubes as detectors for timeseries photometry using light curves of a variety of stars obtained simultaneously with both detectors and under equivalent conditions. A CCD can produce useful data under conditions when a photomultiplier tube cannot, and a CCD will often produce more reliable results even under photometric conditions. I prevent studies of the cataclysmic variables (CV's) AL Com, CP Eri, V Per, and DO Leo made using the time series CCD photometer. AL Com is a very faint CV at high Galactic latitude and a bona fide Population II CV. Some of the properties of AL Com are similar to the dwarf nova WZ Sge and others are similar to the intermediate polar EX Hya, but overall AL Com is unlike any other well-studied cataclysmic variable. CP Eri is shown to be the fifth known interacting binary white dwarf. V Per was the first CV found to have an orbital period near the middle of the

  5. FAINT SUBMILLIMETER GALAXY COUNTS AT 450 {mu}m

    SciTech Connect

    Chen, Chian-Chou; Cowie, Lennox L.; Barger, Amy J.; Casey, Caitlin M.; Lee, Nicholas; Sanders, David B.; Williams, Jonathan P.; Wang, Wei-Hao

    2013-01-10

    We present the results of SCUBA-2 observations at 450 {mu}m and 850 {mu}m of the field lensed by the massive cluster A370. With a total survey area >100 arcmin{sup 2} and 1{sigma} sensitivities of 3.92 and 0.82 mJy beam{sup -1} at 450 and 850 {mu}m, respectively, we find a secure sample of 20 sources at 450 {mu}m and 26 sources at 850 {mu}m with a signal-to-noise ratio (S/N) > 4. Using the latest lensing model of A370 and Monte Carlo simulations, we derive the number counts at both wavelengths. The 450 {mu}m number counts probe a factor of four deeper than the counts recently obtained from the Herschel Space Telescope at similar wavelengths, and we estimate that {approx}47%-61% of the 450 {mu}m extragalactic background light resolved into individual sources with 450 {mu}m fluxes greater than 4.5 mJy. The faint 450 {mu}m sources in the 4{sigma} sample have positional accuracies of 3 arcsec, while brighter sources (S/N >6{sigma}) are good to 1.4 arcsec. Using a deep radio map (1{sigma} {approx} 6 {mu}Jy) we find that the percentage of submillimeter sources having secure radio counterparts is 85% for 450 {mu}m sources with intrinsic fluxes >6 mJy and 67% for 850 {mu}m sources with intrinsic fluxes >4 mJy. We also find that 67% of the >4{sigma} 450 {mu}m sources are detected at 850 {mu}m, while the recovery rate at 450 {mu}m of >4{sigma} 850 {mu}m sources is 54%. Combined with the source redshifts estimated using millimetric flux ratios, the recovered rate is consistent with the scenario where both 450 {mu}m and 20 cm emission preferentially select lower redshift dusty sources, while 850 {mu}m emission traces a higher fraction of dusty sources at higher redshifts. We identify potential counterparts in various wavelengths from X-ray to mid-infrared and measure the multiwavelength photometry, which we then use to analyze the characteristics of the sources. We find three X-ray counterparts to our robust submillimeter sample (S/N > 5), giving an active galactic nucleus

  6. Spitzer ultra faint survey program (surfs up). I. An overview

    SciTech Connect

    Bradač, Maruša; Huang, Kuang-Han; Cain, Benjamin; Hall, Nicholas; Lubin, Lori; Ryan, Russell; Casertano, Stefano; Lemaux, Brian C.; Schrabback, Tim; Hildebrandt, Hendrik; Gonzalez, Anthony H.; Allen, Steve; Von der Linden, Anja; Gladders, Mike; Hinz, Joannah; Zaritsky, Dennis; Treu, Tommaso

    2014-04-20

    Spitzer UltRa Faint SUrvey Program is a joint Spitzer and Hubble Space Telescope Exploration Science program using 10 galaxy clusters as cosmic telescopes to study z ≳ 7 galaxies at intrinsically lower luminosities, enabled by gravitational lensing, than blank field surveys of the same exposure time. Our main goal is to measure stellar masses and ages of these galaxies, which are the most likely sources of the ionizing photons that drive reionization. Accurate knowledge of the star formation density and star formation history at this epoch is necessary to determine whether these galaxies indeed reionized the universe. Determination of the stellar masses and ages requires measuring rest-frame optical light, which only Spitzer can probe for sources at z ≳ 7, for a large enough sample of typical galaxies. Our program consists of 550 hr of Spitzer/IRAC imaging covering 10 galaxy clusters with very well-known mass distributions, making them extremely precise cosmic telescopes. We combine our data with archival observations to obtain mosaics with ∼30 hr exposure time in both 3.6 μm and 4.5 μm in the central 4' × 4' field and ∼15 hr in the flanking fields. This results in 3σ sensitivity limits of ∼26.6 and ∼26.2 AB magnitudes for the central field in the IRAC 3.6 and 4.5 μm bands, respectively. To illustrate the survey strategy and characteristics we introduce the sample, present the details of the data reduction and demonstrate that these data are sufficient for in-depth studies of z ≳ 7 sources (using a z = 9.5 galaxy behind MACS J1149.5+2223 as an example). For the first cluster of the survey (the Bullet Cluster) we have released all high-level data mosaics and IRAC empirical point-spread function models. In the future we plan to release these data products for the entire survey.

  7. Preliminary analysis on faint luminous lightning events recorded by multiple high speed cameras

    NASA Astrophysics Data System (ADS)

    Alves, J.; Saraiva, A. V.; Pinto, O.; Campos, L. Z.; Antunes, L.; Luz, E. S.; Medeiros, C.; Buzato, T. S.

    2013-12-01

    The objective of this work is the study of some faint luminous events produced by lightning flashes that were recorded simultaneously by multiple high-speed cameras during the previous RAMMER (Automated Multi-camera Network for Monitoring and Study of Lightning) campaigns. The RAMMER network is composed by three fixed cameras and one mobile color camera separated by, in average, distances of 13 kilometers. They were located in the Paraiba Valley (in the cities of São José dos Campos and Caçapava), SP, Brazil, arranged in a quadrilateral shape, centered in São José dos Campos region. This configuration allowed RAMMER to see a thunderstorm from different angles, registering the same lightning flashes simultaneously by multiple cameras. Each RAMMER sensor is composed by a triggering system and a Phantom high-speed camera version 9.1, which is set to operate at a frame rate of 2,500 frames per second with a lens Nikkor (model AF-S DX 18-55 mm 1:3.5 - 5.6 G in the stationary sensors, and a lens model AF-S ED 24 mm - 1:1.4 in the mobile sensor). All videos were GPS (Global Positioning System) time stamped. For this work we used a data set collected in four RAMMER manual operation days in the campaign of 2012 and 2013. On Feb. 18th the data set is composed by 15 flashes recorded by two cameras and 4 flashes recorded by three cameras. On Feb. 19th a total of 5 flashes was registered by two cameras and 1 flash registered by three cameras. On Feb. 22th we obtained 4 flashes registered by two cameras. Finally, in March 6th two cameras recorded 2 flashes. The analysis in this study proposes an evaluation methodology for faint luminous lightning events, such as continuing current. Problems in the temporal measurement of the continuing current can generate some imprecisions during the optical analysis, therefore this work aim to evaluate the effects of distance in this parameter with this preliminary data set. In the cases that include the color camera we analyzed the RGB

  8. Day Pass Down the Red Sea

    NASA Video Gallery

    This video over the southeastern Mediterranean Sea and down the coastline of the Red Sea was taken by the crew of Expedition 29 aboard the International Space Station. This sequence of shots was ta...

  9. Evaluation of integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor for decolorization and biodegradation of azo dye acid red 18: comparison of using two types of packing media.

    PubMed

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    Two integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor (FB-SBBR) were operated to evaluate decolorization and biodegradation of azo dye Acid Red 18 (AR18). Volcanic pumice stones and a type of plastic media made of polyethylene were used as packing media in FB-SBBR1 and FB-SBBR2, respectively. Decolorization of AR18 in both reactors followed first-order kinetic with respect to dye concentration. More than 63.7% and 71.3% of anaerobically formed 1-naphthylamine-4-sulfonate (1N-4S), as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase in FB-SBBR1 and FB-SBBR2, respectively. Based on statistical analysis, performance of FB-SBBR2 in terms of COD removal as well as biodegradation of 1N-4S was significantly higher than that of FB-SBBR1. Spherical and rod shaped bacteria were the dominant species of bacteria in the biofilm grown on the pumice stones surfaces, while, the biofilm grown on surfaces of the polyethylene media had a fluffy structure. PMID:23138064

  10. BOO-1137-AN EXTREMELY METAL-POOR STAR IN THE ULTRA-FAINT DWARF SPHEROIDAL GALAXY BOOeTES I

    SciTech Connect

    Norris, John E.; Yong, David; Gilmore, Gerard; Wyse, Rosemary F. G.

    2010-03-01

    We present high-resolution (R {approx} 40,000), high-signal-to-noise ratio (20-90) spectra of an extremely metal-poor giant star Boo-1137 in the 'ultra-faint' dwarf spheroidal galaxy (dSph) Booetes I, absolute magnitude M{sub V} {approx} -6.3. We derive an iron abundance of [Fe/H] = -3.7, making this the most metal-poor star as yet identified in an ultra-faint dSph. Our derived effective temperature and gravity are consistent with its identification as a red giant in Booetes I. Abundances for a further 15 elements have also been determined. Comparison of the relative abundances, [X/Fe], with those of the extremely metal-poor red giants of the Galactic halo shows that Boo-1137 is 'normal' with respect to C and N, the odd-Z elements Na and Al, the iron-peak elements, and the neutron-capture elements Sr and Ba, in comparison with the bulk of the Milky Way halo population having [Fe/H] {approx}<-3.0. The alpha-elements Mg, Si, Ca, and Ti are all higher by DELTA[X/Fe] {approx} 0.2 than the average halo values. Monte Carlo analysis indicates that DELTA[alpha/Fe] values this large are expected with a probability {approx}0.02. The elemental abundance pattern in Boo-1137 suggests inhomogeneous chemical evolution, consistent with the wide internal spread in iron abundances we previously reported. The similarity of most of the Boo-1137 relative abundances with respect to halo values, and the fact that the alpha-elements are all offset by a similar small amount from the halo averages, points to the same underlying galaxy-scale stellar initial mass function, but that Boo-1137 likely originated in a star-forming region where the abundances reflect either poor mixing of supernova (SN) ejecta, or poor sampling of the SN progenitor mass range, or both.

  11. The universe at faint magnitudes. I - Models for the galaxy and the predicted star counts

    NASA Astrophysics Data System (ADS)

    Bahcall, J. N.; Soneira, R. M.

    1980-09-01

    ) are provided. Further ground-based observations at attainable faint magnitudes (mV ≤ 23 mag) would be important. Star counts and (B - V) colors in several widely separated selected fields would permit a more accurate determination of the disk scale length and the spheroid star density and ellipticity. The most effective regions in which to make these observations are specified. The Galaxy model of the disk and spheroid is used to predict the star densities (in B and V) that may be observable with the aid of the Space Telescope down to very faint magnitudes. The stellar density to mV = 28 from the disk and spheroid is predicted to be 104 stars per square degree at the galactic pole. The predicted star counts are insensitive to many of the model parameters, although drastic changes in the shape of the luminosity function outside the presently determined magnitude range could produce measurable departures from the predicted star counts at faint magnitudes. The rotation curve computed solely from the disk and spheroid components decreases beyond about 10 kpc from the center of the Galaxy. A halo with even a relatively small mass density in the Solar neighborhood (ρHalo (Sun) = 0.01 Msun pc-3) can give rise to a flat rotation curve. The stellar content of such a halo would be revealed by observations with Space Telescope cameras if the halo consists of main sequence stars with MV ≲ 19.0 mag (existing observations imply MVMS ≳ 14.0 mag) or faint white dwarfs with MVWD ≲ 17.5 mag (existing observations imply MVWD ≳ 13.0 mag). Existing data imply (M/L)Halo ≳650 (Solar Visual units). The results for V magnitudes are described in the main text; the corresponding results for B magnitudes are summarized in Appendix A. A table of predicted differential and integrated star counts for both V and B magnitudes is given in Appendix B. Simple formulae that reproduce to an accuracy of 15% the predicted model star densities as a function of magnitude, latitude, and longitude

  12. Detection of faint celestial objects by small telescopes

    NASA Astrophysics Data System (ADS)

    Savanevich, Vadim; Bryukhovetskiy, Alexandr; Kozhukhov, Alexandr; Ivaschenko, Yuri; Velichko, Feodor

    an object from class of "Possible objects" by MAST at the multi-frame processing step; • identification of star pattern at the frame via star catalog, calculating rect-angular and angular coordinates of objects. • check-up the obtained measurements with MPC data base, discharge the known objects and forming the decision about new ones. Observations of asteroids were carried out with 60-cm Zeiss reflector at Andrushivka stronomical bservatory (MPC-code A50). Telescope was equipped by FLI PL9000 camera that has CCD array of 3056x3056 pixels. It was possible to detect objects no fainter then 20m of visual brightness for the exposure of 30 sec. It was confirmed, that the method has the reliability of detection of faint objects with nonzero visible motion close to the reliability of detection of motionless ones.

  13. Solar Features Faint but Still Present in 2009

    NASA Astrophysics Data System (ADS)

    Cookson, Angela; Preminger, D.; Chapman, G.

    2009-05-01

    The San Fernando Observatory (SFO) full-disk photometric image archive spans twenty years and includes the cycle 22/23 minimum and the current cycle 23/24 extended minimum. We measure sunspot deficit, faculae/plage/network excess, and disk-integrated variability on red continuum (672.3 nm) and Ca II K-line (393.4 nm) images. A combined plage/network index shows excess remaining above zero as the cycle 23/24 minimum progresses while plage excess alone drops to zero, indicating an absence of large-scale bright regions but a continuing presence of diffuse network. We construct feature-based models of TSI variability and compare our models to the PMOD, ACRIM, and IRMB TSI Composites to determine whether our data reflect the extremely low TSI levels deduced from spacecraft measurements during the current extended solar minimum.

  14. A very faint core-collapse supernova in M85.

    PubMed

    Pastorello, A; Della Valle, M; Smartt, S J; Zampieri, L; Benetti, S; Cappellaro, E; Mazzali, P A; Patat, F; Spiro, S; Turatto, M; Valenti, S

    2007-10-18

    An anomalous transient in the early Hubble-type (S0) galaxy Messier 85 (M85) in the Virgo cluster was discovered by Kulkarni et al. on 7 January 2006 that had very low luminosity (peak absolute R-band magnitude M(R) of about -12) that was constant over more than 80 days, red colour and narrow spectral lines, which seem inconsistent with those observed in any known class of transient events. Kulkarni et al. suggest an exotic stellar merger as the possible origin. An alternative explanation is that the transient in M85 was a type II-plateau supernova of extremely low luminosity, exploding in a lenticular galaxy with residual star-forming activity. This intriguing transient might be the faintest supernova that has ever been discovered. PMID:17943088

  15. A single prolific r-process event preserved in an ultra-faint dwarf galaxy

    NASA Astrophysics Data System (ADS)

    Ji, Alexander; Frebel, Anna; Chiti, Anirudh; Simon, Joshua

    2016-03-01

    The heaviest elements in the periodic table are synthesized through the r-process, but the astrophysical site for r-process nucleosynthesis is still unknown. Ultra-faint dwarf galaxies contain a simple fossil record of early chemical enrichment that may determine this site. Previous measurements found very low levels of neutron-capture elements in ultra-faint dwarfs, preferring supernovae as the r-process site. I present high-resolution chemical abundances of nine stars in the recently discovered ultra-faint dwarf Reticulum II, which display extremely enhanced r-process abundances 2-3 orders of magnitude higher than the other ultra-faint dwarfs. Stars with such extreme r-process enhancements are only rarely found in the Milky Way halo. The r-process abundances imply that the neutron-capture material in Reticulum II was synthesized in a single prolific event that is incompatible with r-process yields from ordinary core-collapse supernovae. Reticulum II provides an opportunity to discriminate whether the source of this pure r-process signature is a neutron star merger or magnetorotationally driven supernova. The single event is also a uniquely stringent constraint on the metal mixing and star formation history of this ultra-faint dwarf galaxy.

  16. VARIABLE STARS IN THE ULTRA-FAINT DWARF SPHEROIDAL GALAXY URSA MAJOR I

    SciTech Connect

    Garofalo, Alessia; Moretti, Maria Ida; Cusano, Felice; Clementini, Gisella; Ripepi, Vincenzo; Dall'Ora, Massimo; Coppola, Giuseppina; Musella, Ilaria; Marconi, Marcella E-mail: fcusano@na.astro.it E-mail: ripepi@na.astro.it E-mail: imoretti@na.astro.it E-mail: ilaria@na.astro.it

    2013-04-10

    We have performed the first study of the variable star population of Ursa Major I (UMa I), an ultra-faint dwarf satellite recently discovered around the Milky Way (MW) by the Sloan Digital Sky Survey. Combining time series observations in the B and V bands from four different telescopes, we have identified seven RR Lyrae stars in UMa I, of which five are fundamental-mode (RRab) and two are first-overtone pulsators (RRc). Our V, B - V color-magnitude diagram of UMa I reaches V {approx} 23 mag (at a signal-to-noise ratio of {approx}6) and shows features typical of a single old stellar population. The mean pulsation period of the RRab stars (P{sub ab}) = 0.628, {sigma} = 0.071 days (or (P{sub ab}) = 0.599, {sigma} = 0.032 days, if V4, the longest period and brightest variable, is discarded) and the position on the period-amplitude diagram suggest an Oosterhoff-intermediate classification for the galaxy. The RR Lyrae stars trace the galaxy horizontal branch (HB) at an average apparent magnitude of (V(RR)) = 20.43 {+-} 0.02 mag (average on six stars and discarding V4), giving in turn a distance modulus for UMa I of (m - M){sub 0} = 19.94 {+-} 0.13 mag, distance d = 97.3{sup +6.0}{sub -5.7} kpc, in the scale where the distance modulus of the Large Magellanic Cloud is 18.5 {+-} 0.1 mag. Isodensity contours of UMa I red giants and HB stars (including the RR Lyrae stars identified in this study) show that the galaxy has an S-shaped structure, which is likely caused by the tidal interaction with the MW. Photometric metallicities were derived for six of the UMa I RR Lyrae stars from the parameters of the Fourier decomposition of the V-band light curves, leading to an average metal abundance of [Fe/H] = -2.29 dex ({sigma} = 0.06 dex, average on six stars) on the Carretta et al. metallicity scale.

  17. Detailed Chemical Abundances in the r-process-rich Ultra-faint Dwarf Galaxy Reticulum 2

    NASA Astrophysics Data System (ADS)

    Roederer, Ian U.; Mateo, Mario; Bailey, John I., III; Song, Yingyi; Bell, Eric F.; Crane, Jeffrey D.; Loebman, Sarah; Nidever, David L.; Olszewski, Edward W.; Shectman, Stephen A.; Thompson, Ian B.; Valluri, Monica; Walker, Matthew G.

    2016-03-01

    The ultra-faint dwarf (UFD) galaxy Reticulum 2 (Ret 2) was recently discovered in images obtained by the Dark Energy Survey. We have observed the four brightest red giants in Ret 2 at high spectral resolution using the Michigan/Magellan Fiber System. We present detailed abundances for as many as 20 elements per star, including 12 elements heavier than the Fe group. We confirm previous detection of high levels of r-process material in Ret 2 (mean [Eu/Fe] = +1.69 ± 0.05) found in three of these stars (mean [Fe/H] = -2.88 ± 0.10). The abundances closely match the r-process pattern found in the well-studied metal-poor halo star CS 22892-052. Such r-process-enhanced stars have not been found in any other UFD galaxy, though their existence has been predicted by at least one model. The fourth star in Ret 2 ([Fe/H] = -3.42 ± 0.20) contains only trace amounts of Sr ([Sr/Fe] = -1.73 ± 0.43) and no detectable heavier elements. One r-process enhanced star is also enhanced in C (natal [C/Fe] ≈ +1.1). This is only the third such star known, which suggests that the nucleosynthesis sites leading to C and r-process enhancements are decoupled. The r-process-deficient star is enhanced in Mg ([Mg/Fe] = +0.81 ± 0.14), and the other three stars show normal levels of α-enhancement (mean [Mg/Fe] = +0.34 ± 0.03). The abundances of other α and Fe-group elements closely resemble those in UFD galaxies and metal-poor halo stars, suggesting that the nucleosynthesis that led to the large r-process enhancements either produced no light elements or produced light-element abundance signatures indistinguishable from normal supernovae. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  18. The very soft X-ray emission of X-ray-faint early-type galaxies

    NASA Technical Reports Server (NTRS)

    Pellegrini, S.; Fabbiano, G.

    1994-01-01

    A recent reanaylsis of Einstein data, and new ROSAT observations, have revealed the presence of at least two components in the X-ray spectra of X-ray faint early-type galaxies: a relatively hard component (kT greater than 1.5 keV), and a very soft component (kT approximately 0.2-0.3 keV). In this paper we address the problem of the nature of the very soft component and whether it can be due to a hot interstellar medium (ISM), or is most likely originated by the collective emission of very soft stellar sources. To this purpose, hydrodynamical evolutionary sequences for the secular behavior of gas flows in ellipticals have been performed, varying the Type Ia supernovae rate of explosion, and the dark matter amount and distribution. The results are compared with the observational X-ray data: the average Einstein spectrum for six X-ray faint early-type galaxies (among which are NGC 4365 and NGC 4697), and the spectrum obtained by the ROSAT pointed observation of NGC 4365. The very soft component could be entirely explained with a hot ISM only in galaxies such as NGC 4697, i.e., when the depth of the potential well-on which the average ISM temperature strongly depends-is quite shallow; in NGC 4365 a diffuse hot ISM would have a temperature larger than that of the very soft component, because of the deeper potential well. So, in NGC 4365 the softest contribution to the X-ray emission comes certainly from stellar sources. As stellar soft X-ray emitters, we consider late-type stellar coronae, supersoft sources such as those discovered by ROSAT in the Magellanic Clouds and M31, and RS CVn systems. All these candidates can be substantial contributors to the very soft emission, though none of them, taken separately, plausibly accounts entirely for its properties. We finally present a model for the X-ray emission of NGC 4365, to reproduce in detail the results of the ROSAT pointed observation, including the Position Sensitive Proportional Counter (PSPC) spectrum and radial

  19. Determination of astrometry and photometry of faint companions in the presence of residual speckle noise

    NASA Astrophysics Data System (ADS)

    Burke, Daniel; Devaney, Nicholas; Gladysz, Szymon

    In this paper we examine approaches to faint companion detection and estimation in multi-spectral images. We will employ the Hotelling observer which is the optimal linear algorithm for signal detection. We have shown how to use this observer to estimate faint object position and brightness in the presence of residual speckle which usually limit astrometric and photometric techniques. These speckles can be reduced by differential imaging techniques such as Angular Differential Imaging and Spectral Differential Imaging. Here we present results based on simulations of adaptive optics corrected images from an ELT which contain quasi-static speckle noise. The simulation includes Angular Differential Imaging to reduce the residual speckle and subsequent multi-wavelenght processing. We examine the feasibility of this approach on simulated ELT observations of faint companions.

  20. The Subaru High-z Quasar Survey: Discovery of Faint z ~ 6 Quasars

    NASA Astrophysics Data System (ADS)

    Kashikawa, Nobunari; Ishizaki, Yoshifumi; Willott, Chris J.; Onoue, Masafusa; Im, Myungshin; Furusawa, Hisanori; Toshikawa, Jun; Ishikawa, Shogo; Niino, Yuu; Shimasaku, Kazuhiro; Ouchi, Masami; Hibon, Pascale

    2015-01-01

    We present the discovery of one or two extremely faint z ~ 6 quasars in 6.5 deg2 utilizing a unique capability of the wide-field imaging of the Subaru/Suprime-Cam. The quasar selection was made in (i'-zB ) and (zB -zR ) colors, where zB and zR are bandpasses with central wavelengths of 8842 Å and 9841 Å, respectively. The color selection can effectively isolate quasars at z ~ 6 from M/L/T dwarfs without the J-band photometry down to zR < 24.0, which is 3.5 mag deeper than the Sloan Digital Sky Survey (SDSS). We have selected 17 promising quasar candidates. The follow-up spectroscopy for seven targets identified one apparent quasar at z = 6.156 with M 1450 = -23.10. We also identified one possible quasar at z = 6.041 with a faint continuum of M 1450 = -22.58 and a narrow Lyα emission with HWHM =427 km s-1, which cannot be distinguished from Lyman α emitters. We derive the quasar luminosity function at z ~ 6 by combining our faint quasar sample with the bright quasar samples by SDSS and CFHQS. Including our data points invokes a higher number density in the faintest bin of the quasar luminosity function than the previous estimate employed. This suggests a steeper faint-end slope than lower z, though it is yet uncertain based on a small number of spectroscopically identified faint quasars, and several quasar candidates still remain to be diagnosed. The steepening of the quasar luminosity function at the faint end does increase the expected emission rate of the ionizing photon; however, it only changes by a factor of approximately two to six. This was found to still be insufficient for the required photon budget of reionization at z ~ 6.

  1. Faint Lyα Emitters, Star-forming Galaxies, and Damped Lyα Systems

    NASA Astrophysics Data System (ADS)

    Rauch, M.; Haehnelt, M.; Bunker, A.; Becker, G.; Marleau, F.; Graham, J.; Cristiani, S.; Jarvis, M.; Lacey, C.; Morris, S.; Peroux, C.; Roettgering, H.; Theuns, T.

    2008-10-01

    We have discovered a population of faint single line emitters, likely to be identified with faint z˜ 3 Lyα emitters and with the host galaxies of damped Lyman alpha systems. The objects appear to constitute the bulk of the star-forming galaxies detected so far from the ground, and are likely to provide the gaseous reservoir from which present-day Milky way type galaxies have formed. Unlike color-selected (yman break galaxies, these objects appear to have low star-formation rates, relatively strong Lyalpha emission, and low masses, metallicities, and dust content (s.a. arXiv:0711.1354).

  2. Big Fish, Little Fish: Two New Ultra-faint Satellites of the Milky Way

    NASA Astrophysics Data System (ADS)

    Belokurov, V.; Walker, M. G.; Evans, N. W.; Gilmore, G.; Irwin, M. J.; Just, D.; Koposov, S.; Mateo, M.; Olszewski, E.; Watkins, L.; Wyrzykowski, L.

    2010-03-01

    We report the discovery of two new Milky Way satellites in the neighboring constellations of Pisces and Pegasus identified in data from the Sloan Digital Sky Survey. Pisces II, an ultra-faint dwarf galaxy lies at the distance of ~180 kpc, some 15° away from the recently detected Pisces I. Segue 3, an ultra-faint star cluster lies at the distance of 16 kpc. We use deep follow-up imaging obtained with the 4-m Mayall Telescope at Kitt Peak National Observatory to derive their structural parameters. Pisces II has a half-light radius of ~60 pc, while Segue 3 is 20 times smaller at only 3 pc.

  3. Digital image profilers for detecting faint sources which have bright companions, phase 2

    NASA Technical Reports Server (NTRS)

    Morris, Elena; Flint, Graham

    1991-01-01

    A breadboard image profiling system developed for the first phase of this project demonstrated the potential for detecting extremely faint optical sources in the presence of light companions. Experimental data derived from laboratory testing of the device supports the theory that image profilers of this type may approach the theoretical limit imposed by photon statistics. The objective of Phase 2 of this program is the development of a ground-based multichannel image profiling system capable of detecting faint stellar objects slightly displaced from brighter stars. We have finalized the multichannel image profiling system and attempted three field tests.

  4. Searching for Faint Exozodiacal Disks: Keck Results and LBTI Status

    NASA Astrophysics Data System (ADS)

    Defrère, D.; Hinz, P.; Mennesson, B.; Millan-Gabet, R.; Skemer, A.; Bailey, V.; Rodigas, T. J.

    2014-01-01

    The possible presence of dust in the habitable zone around nearby main-sequence stars is considered as a major hurdle toward the direct imaging of Earth-like extrasolar planets with future dedicated space-based telescopes (e.g., Roberge et al. 2012). In this context, NASA has funded two ground-based mid-infrared nulling interferometers to combine the large apertures available at the Keck Observatory and the Large Binocular Telescope (LBT). In this poster, we present the preliminary results of the extended survey carried out with the Keck Interferometer Nuller (KIN) between 2008 and 2011 and describe the forthcoming LBTI survey.

  5. The Red Halos of Disk Galaxies

    NASA Astrophysics Data System (ADS)

    Zackrisson, E.; Bergvall, N.; Flynn, C.; Caldwell, B.; Östlin, G.; Micheva, G.

    2008-10-01

    Deep optical/near-IR surface photometry of galaxies outside the Local Group have revealed the existence of faint and very red halos around objects as diverse as spirals and blue compact galaxies. The colors of these structures are much too extreme to be reconciled with resolved stellar populations like those seen in the halos of the Milky Way or M 31, and alternative explanations like dust reddening, high metallicities or nebular emission are also disfavored. A stellar population obeying an extremely bottom-heavy initial mass function, similar to that recently reported for the LMC field population, is on the other hand consistent with all available data. Because of its high mass-to-light ratio, such a population would effectively behave as baryonic dark matter and could account for some of the baryons still missing from local inventories. Here, we report on a number of recent developments in this field.

  6. Constraints on MACHO Dark Matter from Compact Stellar Systems in Ultra-faint Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Brandt, Timothy D.

    2016-06-01

    I show that a recently discovered star cluster near the center of the ultra-faint dwarf galaxy Eridanus II provides strong constraints on massive compact halo objects (MACHOs) of ≳5 M ⊙ as the main component of dark matter. MACHO dark matter will dynamically heat the cluster, driving it to larger sizes and higher velocity dispersions until it dissolves into its host galaxy. The stars in compact ultra-faint dwarf galaxies themselves will be subject to the same dynamical heating; the survival of at least 10 such galaxies places independent limits on MACHO dark matter of masses ≳10 M ⊙. Both Eri II’s cluster and the compact ultra-faint dwarfs are characterized by stellar masses of just a few thousand M ⊙ and half-light radii of 13 pc (for the cluster) and ∼30 pc (for the ultra-faint dwarfs). These systems close the ∼20–100 M ⊙ window of allowed MACHO dark matter and combine with existing constraints from microlensing, wide binaries, and disk kinematics to rule out dark matter composed entirely of MACHOs from ∼10‑7 M ⊙ up to arbitrarily high masses.

  7. Faints, fits, and fatalities from emotion in Shakespeare's characters: survey of the canon

    PubMed Central

    2006-01-01

    Objectives To determine how often Shakespeare's characters faint, fit, or die from extreme emotion; to assess Shakespeare's uniqueness in this regard; and to examine the plausibility of these dramatised events. Design Line by line search through modern editions of these late 16th and early 17th century works for accounts of characters fainting, fitting, or dying while under strong emotion and for no other apparent reason. Data sources All 39 canonical plays by Shakespeare and his three long narrative poems; 18 similar works by seven of Shakespeare's best known contemporaries. Results 10 deaths from strong emotion are recorded by Shakespeare (three occur on stage); all are due to grief, typically at the loss of a loved one. All but two of the deaths are in the playwright's late works. Some deaths are sudden. Another 29 emotion induced deaths are mentioned as possible, but the likelihood of some can be challenged. Transient loss of consciousness is staged or reported in 18 cases (sounding like epilepsy in two) and near fainting in a further 13. Extreme joy is sometimes depicted as a factor in these events. Emotional death and fainting also occur occasionally in works by Shakespeare's contemporaries. Conclusions These dramatic phenomena are part of the early modern belief system but are also plausible by modern understanding of physiology and disease. They teach us not to underestimate the power of the emotions to disturb bodily functions. PMID:17185734

  8. VizieR Online Data Catalog: 72 faint CV candidates in CRTS (Breedt+, 2014)

    NASA Astrophysics Data System (ADS)

    Breedt, E.; Gansicke, B. T.; Drake, A. J.; Rodriguez-Gil, P.; Parsons, S. G.; Marsh, T. R.; Szkody, P.; Schreiber, M. R.; Djorgovski, S. G.

    2016-04-01

    We obtained identification spectra of a total of 72 faint CV candidates identified by the CRTS, using the Gran Telescopio Canarias (GTC; La Palma, Spain) and the Gemini telescopes (North: Mauna Kea, Hawaii and South: Cerro Pachon, Chile). The observations were carried out in service mode during 2010, 2011 and 2013. (5 data files).

  9. View of southeast side, faint "141" sign, Cranes P76 and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of southeast side, faint "141" sign, Cranes P-76 and P-71 are behind, view facing northwest - U.S. Naval Base, Pearl Harbor, Dry Dock No. 1, Latrine, Sixth Street, adjacent to Dry Dock No. 1, Pearl City, Honolulu County, HI

  10. Faint laser pulses versus a single-photon source in free space quantum cryptography

    NASA Astrophysics Data System (ADS)

    Molotkov, S. N.; Potapova, T. A.

    2016-03-01

    In this letter we present estimates for the distance of secret key transmission through free space for three different protocols of quantum key distribution: for BB84 and phase time-coding protocols in the case of a strictly single-photon source, and for the relativistic quantum key distribution protocol in the case of faint laser pulses.

  11. RED AND DEAD: THE PROGENITOR OF SN 2012aw IN M95

    SciTech Connect

    Fraser, M.; Maund, J. R.; Smartt, S. J.; Inserra, C.; Kotak, R.; Reilly, E.; Botticella, M.-T.; Dall'Ora, M.; Tomasella, L.; Benetti, S.; Ciroi, S.; Ochner, P.; Pastorello, A.; Valenti, S.; Eldridge, J. J.; Ergon, M.; Sollerman, J.; Taddia, F.; Mattila, S.; Stephens, A.

    2012-11-01

    Core-collapse supernovae (SNe) are the spectacular finale to massive stellar evolution. In this Letter, we identify a progenitor for the nearby core-collapse SN 2012aw in both ground-based near-infrared and space-based optical pre-explosion imaging. The SN itself appears to be a normal Type II Plateau event, reaching a bolometric luminosity of 10{sup 42} erg s{sup -1} and photospheric velocities of {approx}11,000 km s{sup -1} from the position of the H{beta} P-Cygni minimum in the early SN spectra. We use an adaptive optics image to show that the SN is coincident to within 27 mas with a faint, red source in pre-explosion HST+WFPC2, VLT+ISAAC, and NTT+SOFI images. The source has magnitudes F555W = 26.70 {+-} 0.06, F814W = 23.39 {+-} 0.02, J = 21.1 {+-} 0.2, K = 19.1 {+-} 0.4, which, when compared to a grid of stellar models, best matches a red supergiant. Interestingly, the spectral energy distribution of the progenitor also implies an extinction of A{sub V} > 1.2 mag, whereas the SN itself does not appear to be significantly extinguished. We interpret this as evidence for the destruction of dust in the SN explosion. The progenitor candidate has a luminosity between 5.0 and 5.6 log L/L{sub Sun }, corresponding to a zero-age main-sequence mass between 14 and 26 M{sub Sun} (depending on A{sub V} ), which would make this one of the most massive progenitors found for a core-collapse SN to date.

  12. Extreme Red Quasars in SDSS-BOSS

    NASA Astrophysics Data System (ADS)

    Hamann, Fred; Zakamska, Nadia; Paris, Isabelle; Herbst, Hanna; Villforth, Carolin; Alexandroff, Rachael; Ross, Nicholas; Greene, Jenny; Strauss, Michael

    2015-08-01

    Red quasars are believed to mark a critical transition stage of massive galaxy evolution when a blowout of gas and dust truncates the initial starburst and provides our first visible views of a luminous central AGN. Red quasars could therefore have unusual properties associated with a young evolution stage, such as higher accretion rates, higher rates of mergers and interactions, and more common or more powerful outflows capable of driving a galaxy-wide blowout (e.g., compared to normal blue quasars in presumably more evolved galaxy hosts). The recently completed Baryon Oscillation Spectroscopy Survey (BOSS) of SDSS-III has discovered many more faint quasars with higher redshifts and redder colors than any previous large survey. We combine BOSS spectra with SDSS and Wide-Field Infrared Survey Explorer (WISE) photometry of nearly 100,000 quasars to identify and characterize the red quasar population at redshifts >2. We find a number of strong trends with the amount of reddening/obscuration. For example, red quasars are 5 to 8 times more likely to have broad absorption lines and other "intrinsic" absorption lines that identify quasar-driven outflows. Perhaps most interesting is that extreme red quasars (ERQs), selected via rest-frame UV to near-IR colors similar to Dust Obscured Galaxies (DOGs), have uniquely exotic emission line properties that include extreme velocity shifts between lines and the broadest and most blueshifted [OIII] lines yet discovered (with FWHMs reaching >3000 km/s). We will discuss the implications of these results for models of the structure and evolution of quasars and their host galaxy environments.

  13. Track-Before-Detect Algorithm for Faint Moving Objects based on Random Sampling and Consensus

    NASA Astrophysics Data System (ADS)

    Dao, P.; Rast, R.; Schlaegel, W.; Schmidt, V.; Dentamaro, A.

    2014-09-01

    There are many algorithms developed for tracking and detecting faint moving objects in congested backgrounds. One obvious application is detection of targets in images where each pixel corresponds to the received power in a particular location. In our application, a visible imager operated in stare mode observes geostationary objects as fixed, stars as moving and non-geostationary objects as drifting in the field of view. We would like to achieve high sensitivity detection of the drifters. The ability to improve SNR with track-before-detect (TBD) processing, where target information is collected and collated before the detection decision is made, allows respectable performance against dim moving objects. Generally, a TBD algorithm consists of a pre-processing stage that highlights potential targets and a temporal filtering stage. However, the algorithms that have been successfully demonstrated, e.g. Viterbi-based and Bayesian-based, demand formidable processing power and memory. We propose an algorithm that exploits the quasi constant velocity of objects, the predictability of the stellar clutter and the intrinsically low false alarm rate of detecting signature candidates in 3-D, based on an iterative method called "RANdom SAmple Consensus” and one that can run real-time on a typical PC. The technique is tailored for searching objects with small telescopes in stare mode. Our RANSAC-MT (Moving Target) algorithm estimates parameters of a mathematical model (e.g., linear motion) from a set of observed data which contains a significant number of outliers while identifying inliers. In the pre-processing phase, candidate blobs were selected based on morphology and an intensity threshold that would normally generate unacceptable level of false alarms. The RANSAC sampling rejects candidates that conform to the predictable motion of the stars. Data collected with a 17 inch telescope by AFRL/RH and a COTS lens/EM-CCD sensor by the AFRL/RD Satellite Assessment Center is

  14. The distant red galaxy neighbour population of 1

    NASA Astrophysics Data System (ADS)

    Bornancini, C.; García Lambas, D.

    We study the Distant Red Galaxy (DRG, J-Ks > 2.3) neighbour population of Quasi Stellar Objects (QSOs) selected from the Sloan Digital Sky Survey (SDSS) in the redshift range 1 < z < 2. We perform a similar analysis for optically obscured AGNs (i.e. with a limiting magnitude I > 24) detected in the mid-infrared (24 microns) with the Spitzer Space Telescope and a mean redshift z~2.2 in the Flamingos Extragalactic Survey (FLAMEX). We present results on the cross-correlation function of DRGs around QSOs and optically faint mid-infrared sources. The corresponding correlation length obtained for the QSO sample targets is r_0=5.4+/-1.6 Mpc. For the optically obscured galaxy sample we find r_0=8.9+/-1.4 Mpc. These results indicate that optically faint obscured sources are located in denser environment of evolved red galaxies compare to QSOs.

  15. NEUTRAL GAS OUTFLOWS AND INFLOWS IN INFRARED-FAINT SEYFERT GALAXIES

    SciTech Connect

    Krug, Hannah B.; Veilleux, Sylvain; Rupke, David S. N. E-mail: veilleux@astro.umd.ed

    2010-01-10

    Previous studies of the Na I D interstellar absorption line doublet have shown that galactic winds occur in most galaxies with high infrared luminosities. However, in infrared-bright composite systems where a starburst coexists with an active galactic nucleus (AGN), it is unclear whether the starburst, the AGN, or both are driving the outflows. The present paper describes the results from a search for outflows in 35 infrared-faint Seyferts with 10{sup 9.9}< L{sub IR}/L{sub sun} < 10{sup 11}, or, equivalently, star formation rates (SFRs) of approx0.4-9 M{sub sun} yr{sup -1}, to attempt to isolate the source of the outflow. We find that the outflow detection rates for the infrared-faint Seyfert 1s (6%) and Seyfert 2s (18%) are lower than previously reported for infrared-luminous Seyfert 1s (50%) and Seyfert 2s (45%). The outflow kinematics of infrared-faint and infrared-bright Seyfert 2 galaxies resemble those of starburst galaxies, while the outflow velocities in Seyfert 1 galaxies are significantly larger. Taken together, these results suggest that the AGN does not play a significant role in driving the outflows in most infrared-faint and infrared-bright systems, except the high-velocity outflows seen in Seyfert 1 galaxies. Another striking result of this study is the high rate of detection of inflows in infrared-faint galaxies (39% of Seyfert 1s, 35% of Seyfert 2s), significantly larger than in infrared-luminous Seyferts (15%). This inflow may be contributing to the feeding of the AGN in these galaxies, and potentially provides more than enough material to power the observed nuclear activity over typical AGN lifetimes.

  16. ARE THE FAINT STRUCTURES AHEAD OF SOLAR CORONAL MASS EJECTIONS REAL SIGNATURES OF DRIVEN SHOCKS?

    SciTech Connect

    Lee, Jae-Ok; Moon, Y.-J.; Lee, Kangjin; Lee, Jin-Yi; Lee, Kyoung-Sun; Kim, Sujin E-mail: moonyj@khu.ac.kr

    2014-11-20

    Recently, several studies have assumed that the faint structures ahead of coronal mass ejections (CMEs) are caused by CME-driven shocks. In this study, we have conducted a statistical investigation to determine whether or not the appearance of such faint structures depends on CME speeds. For this purpose, we use 127 Solar and Heliospheric Observatory/Large Angle Spectroscopic COronagraph (LASCO) front-side halo (partial and full) CMEs near the limb from 1997 to 2011. We classify these CMEs into two groups by visual inspection of CMEs in the LASCO-C2 field of view: Group 1 has the faint structure ahead of a CME and Group 2 does not have such a structure. We find the following results. (1) Eighty-seven CMEs belong to Group 1 and 40 CMEs belong to Group 2. (2) Group 1 events have much higher speeds (average = 1230 km s{sup –1} and median = 1199 km s{sup –1}) than Group 2 events (average = 598 km s{sup –1} and median = 518 km s{sup –1}). (3) The fraction of CMEs with faint structures strongly depends on CME speeds (V): 0.93 (50/54) for fast CMEs with V ≥ 1000 km s{sup –1}, 0.65 (34/52) for intermediate CMEs with 500 km s{sup –1} ≤ V < 1000 km s{sup –1}, and 0.14 (3/21) for slow CMEs with V < 500 km s{sup –1}. We also find that the fraction of CMEs with deca-hecto metric type II radio bursts is consistent with the above tendency. Our results indicate that the observed faint structures ahead of fast CMEs are most likely an enhanced density manifestation of CME-driven shocks.

  17. Faint Radio Sources in the NOAO Boötes Field: VLBA Imaging and Optical Identifications

    NASA Astrophysics Data System (ADS)

    Wrobel, J. M.; Taylor, G. B.; Rector, T. A.; Myers, S. T.; Fassnacht, C. D.

    2005-09-01

    As a step toward investigating the parsec-scale properties of faint extragalactic radio sources, the Very Long Baseline Array (VLBA) was used at 5.0 GHz to obtain phase-referenced images of 76 sources in the NOAO Boötes field. These 76 sources were selected from the Faint Images of the Radio Sky at Twenty cm (FIRST) catalog to have peak flux densities above 10 mJy at 5" resolution and deconvolved major diameters of less than 3" at 1.4 GHz. Of these faint radio sources, 57 were identified with accretion-powered radio galaxies and quasars brighter than 25.5 mag in the optical I band. On Very Large Array (VLA) scales at 1.4 GHz, a measure of the compactness of the faint sources (the ratio of the peak flux density from FIRST to the integrated flux density from the NRAO VLA Sky Survey catalog) spans the full range of possibilities arising from source-resolution effects. Of the faint radio sources, 30, or 39+9-7%, were detected with the VLBA at 5.0 GHz with peak flux densities above 6 σ~2 mJy at 2 mas resolution. The VLBA detections occur through the full range of compactness ratios. The stronger VLBA detections can themselves serve as phase-reference calibrators, boding well for opening up much of the radio sky to VLBA imaging. For the adopted cosmology, the VLBA resolution corresponds to 17 pc or finer. Most VLBA detections are unresolved or slightly resolved, but one is diffuse and five show either double or core-jet structures; the properties of these latter six are discussed in detail. Three VLBA detections are unidentified and fainter than 25.5 mag in the optical I band; their properties are highlighted because they likely mark optically obscured active nuclei at high redshift.

  18. NASA Space Observatories Glimpse Faint Afterglow of Nearby Stellar Explosion

    NASA Astrophysics Data System (ADS)

    2005-10-01

    creation of chemical elements such as oxygen through nuclear reactions in their cores. Such observations also help reveal how the interstellar medium (the gas that occupies the vast spaces between the stars) is enriched with chemical elements because of supernova explosions. Later on, these elements are incorporated into new generations of stars and their accompanying planets. Visible only from Earth's southern hemisphere, the LMC is an irregular galaxy lying about 160,000 light-years from the Milky Way. The supernova remnant appears to be about 3,000 years old, but since its light took 160,000 years to reach us, the explosion actually occurred some 163,000 years ago. This composite image of N132D was created by the Hubble Heritage team from visible-light data taken in January 2004 with Hubble's Advanced Camera for Surveys, and X-ray images obtained in July 2000 by Chandra's Advanced CCD Imaging Spectrometer. This marks the first Hubble Heritage image that combines pictures taken by two separate space observatories. The Hubble data include color filters that sample starlight in the blue, green, and red portions of the spectrum, as well as the pink emission from glowing hydrogen gas. The Chandra data are assigned blue in the color composite, in accordance with the much higher energy of the X-rays, emitted from extremely hot gas. This gas does not emit a significant amount of optical light, and was only detected by Chandra. Image Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) Acknowledgment: J.C. Green (Univ. of Colorado) and the Cosmic Origins Spectrograph (COS) GTO team; NASA/CXO/SAO Electronic image files, video, illustrations and additional information are available at: http://hubblesite.org/news/2005/30 http://heritage.stsci.edu/2005/30 The Space Telescope Science Institute (STScI) is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble

  19. The Faint Counterparts of MAMBO Millimeter Sources near the New Technology Telescope Deep Field

    NASA Astrophysics Data System (ADS)

    Dannerbauer, H.; Lehnert, M. D.; Lutz, D.; Tacconi, L.; Bertoldi, F.; Carilli, C.; Genzel, R.; Menten, K. M.

    2004-05-01

    We discuss identifications for 18 sources from our Max-Planck-Millimeter-Bolometer (MAMBO) 1.2 mm survey of the region surrounding the NTT Deep Field. We have obtained accurate positions from Very Large Array 1.4 GHz interferometry, and in a few cases IRAM millimeter interferometry, and have also made deep BVRIzJK imaging at ESO. We find thirteen 1.2 mm sources associated with optical/near-infrared objects in the magnitude range K=19.0-22.5, while five are blank fields at K>22. We argue from a comparison of optical/near-infrared photometric redshifts and radio/millimeter redshift estimates that two of the 13 optical/near-infrared objects are likely foreground objects distinct from the dust sources, one of them possibly lensing the millimeter source. The median redshift of the radio-identified millimeter sources is ~2.6 from the radio/millimeter estimator, and the median optical/near-infrared photometric redshifts for the objects with counterparts is ~2.1. This suggests that those radio-identified millimeter sources without optical/near-infrared counterparts tend to lie at higher redshifts than those with optical/near-infrared counterparts. Compared to published identifications of objects from 850 μm surveys of similar depth, the median K and I magnitudes of our counterparts are roughly 2 mag fainter, and the dispersion of I-K colors is less. Real differences in the median redshifts, residual misidentifications with bright objects, cosmic variance, and small-number statistics are likely to contribute to this significant difference, which also affects redshift measurement strategies. Some of the counterparts are red in J-K (>~20%), but the contribution of such millimeter objects to the recently studied population of near-infrared-selected (Js-Ks>2.3) high-redshift galaxies is only of order a few percent. The recovery rate of MAMBO sources by preselection of optically faint radio sources is relatively low (~25%), in contrast to some claims of a higher rate for

  20. THE SUBARU HIGH-z QUASAR SURVEY: DISCOVERY OF FAINT z ∼ 6 QUASARS

    SciTech Connect

    Kashikawa, Nobunari; Furusawa, Hisanori; Niino, Yuu; Ishizaki, Yoshifumi; Onoue, Masafusa; Toshikawa, Jun; Ishikawa, Shogo; Willott, Chris J.; Im, Myungshin; Shimasaku, Kazuhiro; Ouchi, Masami; Hibon, Pascale

    2015-01-01

    We present the discovery of one or two extremely faint z ∼ 6 quasars in 6.5 deg{sup 2} utilizing a unique capability of the wide-field imaging of the Subaru/Suprime-Cam. The quasar selection was made in (i'-z{sub B} ) and (z{sub B} -z{sub R} ) colors, where z{sub B} and z{sub R} are bandpasses with central wavelengths of 8842 Å and 9841 Å, respectively. The color selection can effectively isolate quasars at z ∼ 6 from M/L/T dwarfs without the J-band photometry down to z{sub R} < 24.0, which is 3.5 mag deeper than the Sloan Digital Sky Survey (SDSS). We have selected 17 promising quasar candidates. The follow-up spectroscopy for seven targets identified one apparent quasar at z = 6.156 with M {sub 1450} = –23.10. We also identified one possible quasar at z = 6.041 with a faint continuum of M {sub 1450} = –22.58 and a narrow Lyα emission with HWHM =427 km s{sup –1}, which cannot be distinguished from Lyman α emitters. We derive the quasar luminosity function at z ∼ 6 by combining our faint quasar sample with the bright quasar samples by SDSS and CFHQS. Including our data points invokes a higher number density in the faintest bin of the quasar luminosity function than the previous estimate employed. This suggests a steeper faint-end slope than lower z, though it is yet uncertain based on a small number of spectroscopically identified faint quasars, and several quasar candidates still remain to be diagnosed. The steepening of the quasar luminosity function at the faint end does increase the expected emission rate of the ionizing photon; however, it only changes by a factor of approximately two to six. This was found to still be insufficient for the required photon budget of reionization at z ∼ 6.

  1. The Faint End of the Quasar Luminosity Function at z ~ 4

    NASA Astrophysics Data System (ADS)

    Glikman, Eilat; Bogosavljević, Milan; Djorgovski, S. G.; Stern, Daniel; Dey, Arjun; Jannuzi, Buell T.; Mahabal, Ashish

    2010-02-01

    The evolution of the quasar luminosity function (QLF) is one of the basic cosmological measures providing insight into structure formation and mass assembly in the universe. We have conducted a spectroscopic survey to find faint quasars (-26.0 < M 1450 < -22.0) at redshifts z = 3.8-5.2 in order to measure the faint end of the QLF at these early times. Using available optical imaging data from portions of the NOAO Deep Wide-Field Survey and the Deep Lens Survey, we have color-selected quasar candidates in a total area of 3.76 deg2. Thirty candidates have R <= 23 mag. We conducted spectroscopic follow-up for 28 of our candidates and found 23 QSOs, 21 of which are reported here for the first time, in the 3.74 < z < 5.06 redshift range. We estimate our survey completeness through detailed Monte Carlo simulations and derive the first measurement of the density of quasars in this magnitude and redshift interval. We find that the binned luminosity function (LF) is somewhat affected by the K-correction used to compute the rest-frame absolute magnitude at 1450 Å. Considering only our R <= 23 sample, the best-fit single power law (Φ vprop L β) gives a faint-end slope β = -1.6 ± 0.2. If we consider our larger, but highly incomplete sample going 1 mag fainter, we measure a steeper faint-end slope -2 < β < -2.5. In all cases, we consistently find faint-end slopes that are steeper than expected based on measurements at z ~ 3. We combine our sample with bright quasars from the Sloan Digital Sky Survey to derive parameters for a double-power-law LF. Our best fit finds a bright-end slope, α = -2.4 ± 0.2, and faint-end slope, β = -2.3 ± 0.2, without a well-constrained break luminosity. This is effectively a single power law, with β = -2.7 ± 0.1. We use these results to place limits on the amount of ultraviolet radiation produced by quasars and find that quasars are able to ionize the intergalactic medium at these redshifts. The data presented herein were obtained at the

  2. Discovery of an Ultra-faint Dwarf Galaxy in the Intracluster Field of the Virgo Center: A Fossil of the First Galaxies?

    NASA Astrophysics Data System (ADS)

    Jang, In Sung; Lee, Myung Gyoon

    2014-11-01

    Ultra-faint dwarf galaxies (UFDs) are newcomers among galaxies, and are the faintest galaxies in the observed universe. To date, they have only been found around the Milky Way Galaxy and M31 in the Local Group. We present the discovery of a UFD in the intracluster field in the core of the Virgo cluster (Virgo UFD1), which is far from any massive galaxies. The color-magnitude diagram of the resolved stars in this galaxy shows a narrow red giant branch, similar to those of metal-poor globular clusters in the Milky Way. We estimate its distance by comparing the red giant branch with isochrones, and we obtain a value 16.4 ± 0.4 Mpc. This shows that it is indeed a member of the Virgo cluster. From the color of the red giants we estimate its mean metallicity to be very low, [Fe/H] =-2.4 ± 0.4. Its absolute V-band magnitude and effective radius are derived to be MV = -6.5 ± 0.2 and r eff = 81 ± 7 pc, much fainter and smaller than the classical dwarf spheroidal galaxies. Its central surface brightness is estimated to be as low as μ V, 0 = 26.37 ± 0.05 mag arcsec-2. Its properties are similar to those of the Local Group analogs. No evidence of tidal features are found in this galaxy. Considering its narrow red giant branch with no asymptotic giant branch stars, low metallicity, and location, it may be a fossil remnant of the first galaxies.

  3. DISCOVERY OF AN ULTRA-FAINT DWARF GALAXY IN THE INTRACLUSTER FIELD OF THE VIRGO CENTER: A FOSSIL OF THE FIRST GALAXIES?

    SciTech Connect

    Jang, In Sung; Lee, Myung Gyoon E-mail: mglee@astro.snu.ac.kr

    2014-11-01

    Ultra-faint dwarf galaxies (UFDs) are newcomers among galaxies, and are the faintest galaxies in the observed universe. To date, they have only been found around the Milky Way Galaxy and M31 in the Local Group. We present the discovery of a UFD in the intracluster field in the core of the Virgo cluster (Virgo UFD1), which is far from any massive galaxies. The color-magnitude diagram of the resolved stars in this galaxy shows a narrow red giant branch, similar to those of metal-poor globular clusters in the Milky Way. We estimate its distance by comparing the red giant branch with isochrones, and we obtain a value 16.4 ± 0.4 Mpc. This shows that it is indeed a member of the Virgo cluster. From the color of the red giants we estimate its mean metallicity to be very low, [Fe/H] =–2.4 ± 0.4. Its absolute V-band magnitude and effective radius are derived to be M{sub V} = –6.5 ± 0.2 and r {sub eff} = 81 ± 7 pc, much fainter and smaller than the classical dwarf spheroidal galaxies. Its central surface brightness is estimated to be as low as μ {sub V,} {sub 0} = 26.37 ± 0.05 mag arcsec{sup –2}. Its properties are similar to those of the Local Group analogs. No evidence of tidal features are found in this galaxy. Considering its narrow red giant branch with no asymptotic giant branch stars, low metallicity, and location, it may be a fossil remnant of the first galaxies.

  4. Optical and near-IR observations of the faint and fast 2008ha-like supernova 2010ae

    NASA Astrophysics Data System (ADS)

    Stritzinger, M. D.; Hsiao, E.; Valenti, S.; Taddia, F.; Rivera-Thorsen, T. J.; Leloudas, G.; Maeda, K.; Pastorello, A.; Phillips, M. M.; Pignata, G.; Baron, E.; Burns, C. R.; Contreras, C.; Folatelli, G.; Hamuy, M.; Höflich, P.; Morrell, N.; Prieto, J. L.; Benetti, S.; Campillay, A.; Haislip, J. B.; LaClutze, A. P.; Moore, J. P.; Reichart, D. E.

    2014-01-01

    A comprehensive set of optical and near-infrared (NIR) photometry and spectroscopy is presented for the faint and fast 2008ha-like supernova (SN) 2010ae. Contingent on the adopted value of host extinction, SN 2010ae reached a peak brightness of -13.8 > MV > -15.3 mag, while modeling of the UVOIR light curve suggests it produced 0.003-0.007 M⊙ of 56Ni, ejected 0.30-0.60 M⊙ of material, and had an explosion energy of 0.04-0.30 × 1051 erg. The values of these explosion parameters are similar to the peculiar SN 2008ha -for which we also present previously unpublished early phase optical and NIR light curves - and places these two transients at the faint end of the 2002cx-like SN population. Detailed inspection of the post-maximum NIR spectroscopic sequence indicates the presence of a multitude of spectral features, which are identified through SYNAPPS modeling to be mainly attributed to Co ii. Comparison with a collection of published and unpublished NIR spectra of other 2002cx-like SNe, reveals that a Co ii footprint is ubiquitous to this subclass of transients, providing a link to Type Ia SNe. A visual-wavelength spectrum of SN 2010ae obtained at +252 days past maximum shows a striking resemblance to a similar epoch spectrum of SN 2002cx. However, subtle differences in the strength and ratio of calcium emission features, as well as diversity among similar epoch spectra of other 2002cx-like SNe indicates a range of physical conditions of the ejecta, highlighting the heterogeneous nature of thispeculiar class of transients. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile (ESO Programs 082.A-0526, 084.D-0719, 088.D-0222, 184.D-1140, and 386.D-0966); the Gemini Observatory, Cerro Pachon, Chile (Gemini Programs GS-2010A-Q-14 and GS-2010A-Q-38); the Magellan 6.5 m telescopes at Las Campanas Observatory; and the SOAR telescope.Tables 1-5 and Appendix A are available in electronic form at http

  5. BIG FISH, LITTLE FISH: TWO NEW ULTRA-FAINT SATELLITES OF THE MILKY WAY

    SciTech Connect

    Belokurov, V.; Walker, M. G.; Evans, N. W.; Gilmore, G.; Irwin, M. J.; Koposov, S.; Watkins, L.; Wyrzykowski, L.; Just, D.; Olszewski, E.; Mateo, M. E-mail: walker@ast.cam.ac.uk

    2010-03-20

    We report the discovery of two new Milky Way satellites in the neighboring constellations of Pisces and Pegasus identified in data from the Sloan Digital Sky Survey. Pisces II, an ultra-faint dwarf galaxy lies at the distance of {approx}180 kpc, some 15 deg. away from the recently detected Pisces I. Segue 3, an ultra-faint star cluster lies at the distance of 16 kpc. We use deep follow-up imaging obtained with the 4-m Mayall Telescope at Kitt Peak National Observatory to derive their structural parameters. Pisces II has a half-light radius of {approx}60 pc, while Segue 3 is 20 times smaller at only 3 pc.

  6. Variable Stars in the Field of the Hydra II Ultra-Faint Dwarf Galaxy

    NASA Astrophysics Data System (ADS)

    Vivas, Anna Katherina; Olsen, Knut A.; Blum, Robert D.; Nidever, David L.; Walker, Alistair R.; Martin, Nicolas; Besla, Gurtina; Gallart, Carme; Van Der Marel, Roeland P.; Majewski, Steven R.; Munoz, Ricardo; Kaleida, Catherine C.; Saha, Abhijit; Conn, Blair; Jin, Shoko

    2016-06-01

    We searched for variable stars in Hydra II, one of the recently discovered ultra-faint dwarf satellites of the Milky Way, using gri time-series obtained with the Dark Energy Camera (DECam) at Cerro Tololo Inter-American Observatory, Chile. We discovered one RR Lyrae star in the galaxy which was used to derive a distance of 154±8 kpc to this system and to re-calculate its absolute magnitude and half-light radius.A comparison with other RR Lyrae stars in ultra-faint systems indicates similar pulsational properties among them, which are different to those found among halo field stars and those in the largest of the Milky Way satellites. We also report the discovery of 31 additional short period variables in the field of view (RR Lyrae, SX Phe, eclipsing binaries, and a likely anomalous cepheid) which are likely not related with Hydra II.

  7. Hubble Space Telescope Faint Object Camera calculated point-spread functions.

    PubMed

    Lyon, R G; Dorband, J E; Hollis, J M

    1997-03-10

    A set of observed noisy Hubble Space Telescope Faint Object Camera point-spread functions is used to recover the combined Hubble and Faint Object Camera wave-front error. The low-spatial-frequency wave-front error is parameterized in terms of a set of 32 annular Zernike polynomials. The midlevel and higher spatial frequencies are parameterized in terms of set of 891 polar-Fourier polynomials. The parameterized wave-front error is used to generate accurate calculated point-spread functions, both pre- and post-COSTAR (corrective optics space telescope axial replacement), suitable for image restoration at arbitrary wavelengths. We describe the phase-retrieval-based recovery process and the phase parameterization. Resultant calculated precorrection and postcorrection point-spread functions are shown along with an estimate of both pre- and post-COSTAR spherical aberration. PMID:18250862

  8. A Faint Near-Infrared Counterpart to the AXP 1E 2259+58.6

    NASA Technical Reports Server (NTRS)

    Hulleman, F.; Tennant, Allyn F., Jr.; vanKerkwijk, M. H.; Kulkarni, S. R.; Kouveliotou, C.; Patel, S. K.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    We present near-infrared and optical observations of the field of the Anomalous X-ray Pulsar 1E 2259+58.6 taken with the Keck telescope. We derive a subarcsecond Chandra position and tie it to our optical reference frame using other stars in the field. We find a very faint source, K(s) = 21.7 +/- 0.2 mag, with a position coincident with the Chandra position. We argue that this is the counterpart. In the J, I, and R bands, we derive (two sigma) limits of 23.8, 25.6 and 26.4mag, respectively. As with 4U 0142+61, for which a similarly faint counterpart was found, our results are inconsistent with models in which the source is powered by accretion from a disk. The only model that is not inconsistent, appears to be that in which 1E 2259+58.6 is a magnetar.

  9. On the faint-end of the high-z galaxy luminosity function

    NASA Astrophysics Data System (ADS)

    Yue, Bin; Ferrara, Andrea; Xu, Yidong

    2016-08-01

    Recent measurements of the Luminosity Function (LF) of galaxies in the Epoch of Reionization (EoR, zlower.5ex buildrel> over ˜ 6) indicate a very steep increase of the number density of low-mass galaxies populating the LF faint-end. However, as star formation in low-mass halos can be easily depressed or even quenched by ionizing radiation, a turnover is expected at some faint UV magnitudes. Using a physically-motivated analytical model, we quantify reionization feedback effects on the LF faint-end shape. We find that if reionization feedback is neglected, the power-law Schechter parameterization characterizing the LF faint-end remains valid up to absolute UV magnitude ˜-9. If instead radiative feedback is strong enough that quenches star formation in halos with circular velocity smaller than 50 km s-1, the LF starts to drop at absolute UV magnitude ˜-15, i.e. slightly below the detection limits of current (unlensed) surveys at z ˜ 5. The LFs may rise again at higher absolute UV magnitude, where, as a result of interplay between reionization process and galaxy formation, most of the galaxy light is from relic stars formed before the EoR. We suggest that the galaxy number counts data, particularly in lensed fields, can put strong constraints on reionization feedback. In models with stronger reionization feedback, stars in galaxies with absolute UV magnitude higher than ˜-13 and smaller than ˜-8 are typically older. Hence, the stellar age - UV magnitude relation can be used as an alternative feedback probe.

  10. Eight ultra-faint galaxy candidates discovered in year two of the Dark Energy Survey

    SciTech Connect

    Drlica-Wagner, A.

    2015-11-04

    We report the discovery of eight new ultra-faint dwarf galaxy candidates in the second year of optical imaging data from the Dark Energy Survey (DES). Six of these candidates are detected at high confidence, while two lower-confidence candidates are identified in regions of non-uniform survey coverage. The new stellar systems are found by three independent automated search techniques and are identified as overdensities of stars, consistent with the isochrone and luminosity function of an old and metal-poor simple stellar population. The new systems are faint (MV > -4.7 ) and span a range of physical sizes (17 pc < r1/2 < 181pc) and heliocentric distances (25 kpc < D < 214 kpc). All of the new systems have central surface brightnesses consistent with known ultra-faint dwarf galaxies (μ 27.5 mag arcsec -2). Roughly half of the DES candidates are more distant, less luminous, and/or have lower surface brightnesses than previously known Milky Way satellite galaxies. Most of the candidates are found in the southern part of the DES footprint close to the Magellanic Clouds. We find that the DES data alone exclude (p < 10-3) a spatially isotropic distribution of Milky Way satellites and that the observed distribution can be well, though not uniquely, described by an association between several of the DES satellites and the Magellanic system. Furthermore, our model predicts that the full sky may hold ~100 ultra-faint galaxies with physical properties comparable to the DES satellites and that 20%–30% of these would be spatially associated with the Magellanic Clouds.

  11. Eight ultra-faint galaxy candidates discovered in year two of the Dark Energy Survey

    DOE PAGESBeta

    Drlica-Wagner, A.

    2015-11-04

    We report the discovery of eight new ultra-faint dwarf galaxy candidates in the second year of optical imaging data from the Dark Energy Survey (DES). Six of these candidates are detected at high confidence, while two lower-confidence candidates are identified in regions of non-uniform survey coverage. The new stellar systems are found by three independent automated search techniques and are identified as overdensities of stars, consistent with the isochrone and luminosity function of an old and metal-poor simple stellar population. The new systems are faint (MV > -4.7 ) and span a range of physical sizes (17 pc < r1/2more » < 181pc) and heliocentric distances (25 kpc < D⊙ < 214 kpc). All of the new systems have central surface brightnesses consistent with known ultra-faint dwarf galaxies (μ 27.5 mag arcsec -2). Roughly half of the DES candidates are more distant, less luminous, and/or have lower surface brightnesses than previously known Milky Way satellite galaxies. Most of the candidates are found in the southern part of the DES footprint close to the Magellanic Clouds. We find that the DES data alone exclude (p < 10-3) a spatially isotropic distribution of Milky Way satellites and that the observed distribution can be well, though not uniquely, described by an association between several of the DES satellites and the Magellanic system. Furthermore, our model predicts that the full sky may hold ~100 ultra-faint galaxies with physical properties comparable to the DES satellites and that 20%–30% of these would be spatially associated with the Magellanic Clouds.« less

  12. Eight Ultra-faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Drlica-Wagner, A.; Bechtol, K.; Rykoff, E. S.; Luque, E.; Queiroz, A.; Mao, Y.-Y.; Wechsler, R. H.; Simon, J. D.; Santiago, B.; Yanny, B.; Balbinot, E.; Dodelson, S.; Fausti Neto, A.; James, D. J.; Li, T. S.; Maia, M. A. G.; Marshall, J. L.; Pieres, A.; Stringer, K.; Walker, A. R.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Martini, P.; Miquel, R.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Roodman, A.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Tucker, D.; Vikram, V.; Wester, W.; Zhang, Y.; Zuntz, J.; DES Collaboration

    2015-11-01

    We report the discovery of eight new ultra-faint dwarf galaxy candidates in the second year of optical imaging data from the Dark Energy Survey (DES). Six of these candidates are detected at high confidence, while two lower-confidence candidates are identified in regions of non-uniform survey coverage. The new stellar systems are found by three independent automated search techniques and are identified as overdensities of stars, consistent with the isochrone and luminosity function of an old and metal-poor simple stellar population. The new systems are faint (MV > -4.7 {mag}) and span a range of physical sizes (17 {pc} < r1/2 < 181 {pc}) and heliocentric distances (25 kpc < D⊙ < 214 kpc). All of the new systems have central surface brightnesses consistent with known ultra-faint dwarf galaxies (μ ≳ 27.5 {mag} {arcsec}-2). Roughly half of the DES candidates are more distant, less luminous, and/or have lower surface brightnesses than previously known Milky Way satellite galaxies. Most of the candidates are found in the southern part of the DES footprint close to the Magellanic Clouds. We find that the DES data alone exclude (p < 10-3) a spatially isotropic distribution of Milky Way satellites and that the observed distribution can be well, though not uniquely, described by an association between several of the DES satellites and the Magellanic system. Our model predicts that the full sky may hold ˜100 ultra-faint galaxies with physical properties comparable to the DES satellites and that 20%-30% of these would be spatially associated with the Magellanic Clouds.

  13. Faint Radio Sources in the NOAO Bootes Field. VLBA Imaging And Optical Identifications

    SciTech Connect

    Wrobel, J.M.; Taylor, Greg B.; Rector, T.A.; Myers, S.T.; Fassnacht, C.D.; /UC, Davis

    2005-06-13

    As a step toward investigating the parsec-scale properties of faint extragalactic radio sources, the Very Long Baseline Array (VLBA) was used at 5.0 GHz to obtain phase-referenced images of 76 sources in the NOAO Booetes field. These 76 sources were selected from the FIRST catalog to have peak flux densities above 10 mJy at 5'' resolution and deconvolved major diameters of less than 3'' at 1.4 GHz. Fifty-five of these faint radio sources were identified with accretion-powered radio galaxies and quasars brighter than 25.5 mag in the optical I band. On VLA scales at 1.4 GHz, a measure of the compactness of the faint sources (the ratio of the peak flux density from FIRST to the integrated flux density from the NVSS catalog) spans the full range of possibilities arising from source-resolution effects. Thirty of the faint radio sources, or 39{sub -7}{sup +9}%, were detected with the VLBA at 5.0 GHz with peak flux densities above 6 {sigma} {approx} 2 mJy at 2 mas resolution. The VLBA detections occur through the full range of compactness ratios. The stronger VLBA detections can themselves serve as phase-reference calibrators, boding well for opening up much of the radio sky to VLBA imaging. For the adopted cosmology, the VLBA resolution corresponds to 17 pc or finer. Most VLBA detections are unresolved or slightly resolved but one is diffuse and five show either double or core-jet structures; the properties of these latter six are discussed in detail. Eight VLBA detections are unidentified and fainter than 25.5 mag in the optical I band; their properties are highlighted because they likely mark optically-obscured active nuclei at high redshift.

  14. Prognosis of glioblastoma with faint MGMT methylation-specific PCR product.

    PubMed

    Hsu, Chih-Yi; Ho, Hsiang-Ling; Lin, Shih-Chieh; Chang-Chien, Yi-Chun; Chen, Ming-Hsiung; Hsu, Sanford Ping-Chuan; Yen, Yu-Shu; Guo, Wan-You; Ho, Donald Ming-Tak

    2015-03-01

    Methylation-specific polymerase chain reaction (MSP) for the promoter methylation status of O(6)-methylguanine-DNA-methyltranferase (MGMT) gene theoretically provides a positive or negative result. However, the faint MSP product is difficult to interpret. The aim of this study was to evaluate the significance of faint MSP product in glioblastoma (GBM). Critical concentrations of methylated control DNA, i.e., 100, 1, 0.5 and 0 % were run parallel with 116 newly diagnosed GBMs in order to standardize the interpretation and to distinguish positive (+), equivocal (±), and negative (-; unmethylated) results. Cases with the faint MSP product and its intensity between those of 1 and 0.5 % DNA controls were considered equivocal (±). MGMT methylation quantifications were also determined by quantitative real-time MSP (qMSP) and pyrosequencing (PSQ), and protein expression was detected by immunohistochemistry. There were significant correlations between MSP and all the aforementioned studies. The concordance rates between the MSP+ and qMSP+ cases, as well as the MSP- and qMSP- cases were 100 %, and the MSP± cases comprised 76.5 % of qMSP+ cases and 23.5 % of qMSP- cases. PSQ study showed that heterogeneous methylation was more frequently encountered in the MSP± cases. Multivariate analyses disclosed that although the overall survival of the MSP± cases was indistinct from that of the MSP+ cases, its progression free survival was significantly worse and was indistinct from that of the MSP- cases. In conclusion, GBMs with faint MGMT MSP products should be distinguished from MSP+ cases as their behaviors were different. PMID:25575938

  15. Faint electric treatment-induced rapid and efficient delivery of extraneous hydrophilic molecules into the cytoplasm.

    PubMed

    Hasan, Mahadi; Nishimoto, Akinori; Ohgita, Takashi; Hama, Susumu; Kashida, Hiromu; Asanuma, Hiroyuki; Kogure, Kentaro

    2016-04-28

    Effective delivery of extraneous molecules into the cytoplasm of the target cells is important for several drug therapies. Previously, we showed effective in vivo transdermal delivery of naked siRNA into skin cells induced by faint electric treatment (ET) iontophoresis, and significant suppression of target mRNA levels (Kigasawa et al., Int. J. Pharm., 2010). This result indicates that electricity promoted the delivery of siRNA into cytoplasm. In the present study, we analyzed the intracellular delivery of naked anti-luciferase siRNA by faint ET, and found that the luciferase activity of cells expressing luciferase was reduced by in vitro ET like in vivo iontophoresis. Cellular uptake of fluorescent-label siRNA was increased by ET, while low temperature exposure, macropinocytosis inhibitor amiloride and caveolae-mediated endocytosis inhibitor filipin significantly prevented siRNA uptake. These results indicate that the cellular uptake mechanism involved endocytosis. In addition, voltage sensitive fluorescent dye DiBAC4 (3) penetration was increased by ET, and the transient receptor potential channel inhibitor SKF96365 reduced siRNA uptake, suggesting that faint ET reduced membrane potentials by changing intracellular ion levels. Moreover, to analyze cytoplasmic delivery, we used in-stem molecular beacon (ISMB), which fluoresces upon binding to target mRNA in the cytoplasm. Surprisingly, cytoplasmic ISMB fluorescence appeared rapidly and homogeneously after ET, indicating that cytoplasmic delivery is markedly enhanced by ET. In conclusion, we demonstrated for the first time that faint ET can enhance cellular uptake and cytoplasmic delivery of extraneous molecules. PMID:26944781

  16. FAME Astrometry of Faint Objects and the Kinematics of the Galaxy

    NASA Astrophysics Data System (ADS)

    Salim, S.; Gould, A.; Olling, R.

    2001-12-01

    We explore what the Full-Sky Astrometric Mapping Explorer (FAME) can achieve by observing a ``small'' (< 106) sample of faint objects (R< ~18) in addition to its standard R<15 magnitude limited catalog of 40x 106 stars. Observing some 50,000 quasars will improve the accuracy of the reference frame from 16 micro-as/yr to 6 micro-as/yr, allowing proper motion of the Galactic center due to reflex of the Sun's motion to be determined with an accuracy of 0.1%. It will also permit very accurate proper motions of the Magellanic Clouds. Quasar observations also offer a powerful check on any unmodeled parallax systematics. Proper motions of 30,000 faint field blue horizontal branch stars will allow stellar halo rotation to be mapped to beyond 35 kpc. Halo substructures producing clumps in the velocity space will be detectable to 10 kpc. In addition to this, allowing inclusion of objects with R>15 will increase the number of good parallaxes of late M-dwarfs 30-fold, and provide distances of over 200 L-dwarfs. FAME could obtain good (10%) parallaxes for 3700 white dwarfs, a 10-fold increase over the R<15 sample. These parallaxes will yield precise mass and luminosity functions. Candidate quasars, BHB stars, and nearby stars will be selected from existing and planned surveys (SDSS, USNO, 2MASS, etc.) The total number of faint candidates should be about 500,000, a small fraction of the FAME input catalog.

  17. Results and analyses of faint field galaxy surveys with the Keck Telescope

    NASA Astrophysics Data System (ADS)

    Hogg, D. W.

    1996-12-01

    A large collaboration at Caltech has been using the Keck and other telescopes to perform UBVRIKL imaging and take spectra of faint galaxies. The spectroscopic samples contain several hundred objects to K=20 mag or R=24 mag and the imaging samples contain thousands of sources to R~ 27. Faint field galaxies are found to be strongly clustered in velocity space; the angular coherence, masses and morphologies in configuration space of these structures are investigated. In cooperation with the University of Hawaii group, the luminosity function of galaxies is computed in the near-infrared; strong evolution is found in the number of low-luminosity galaxies to z~ 1, although the statistical properties of high-luminosity objects are relatively constant. A range of models for the faint galaxy counts are constructed, not on the basis of a priori information about galaxy properties (from, say, cosmogonic theory) but rather by ``inverting'' the data under a range of qualitatively distinct simplifying assumptions. Predictions are made for ongoing or future imaging and spectroscopy surveys which will clearly distinguish the models. The prospects for a ``meta-analysis'' of a large collection of heterogeneous surveys to create consistent galaxy evolution models from z=0 to the highest observed redshifts are discussed.

  18. Infrared-faint radio sources are at high redshifts. Spectroscopic redshift determination of infrared-faint radio sources using the Very Large Telescope

    NASA Astrophysics Data System (ADS)

    Herzog, A.; Middelberg, E.; Norris, R. P.; Sharp, R.; Spitler, L. R.; Parker, Q. A.

    2014-07-01

    Context. Infrared-faint radio sources (IFRS) are characterised by relatively high radio flux densities and associated faint or even absent infrared and optical counterparts. The resulting extremely high radio-to-infrared flux density ratios up to several thousands were previously known only for high-redshift radio galaxies (HzRGs), suggesting a link between the two classes of object. However, the optical and infrared faintness of IFRS makes their study difficult. Prior to this work, no redshift was known for any IFRS in the Australia Telescope Large Area Survey (ATLAS) fields which would help to put IFRS in the context of other classes of object, especially of HzRGs. Aims: This work aims at measuring the first redshifts of IFRS in the ATLAS fields. Furthermore, we test the hypothesis that IFRS are similar to HzRGs, that they are higher-redshift or dust-obscured versions of these massive galaxies. Methods: A sample of IFRS was spectroscopically observed using the Focal Reducer and Low Dispersion Spectrograph 2 (FORS2) at the Very Large Telescope (VLT). The data were calibrated based on the Image Reduction and Analysis Facility (IRAF) and redshifts extracted from the final spectra, where possible. This information was then used to calculate rest-frame luminosities, and to perform the first spectral energy distribution modelling of IFRS based on redshifts. Results: We found redshifts of 1.84, 2.13, and 2.76, for three IFRS, confirming the suggested high-redshift character of this class of object. These redshifts and the resulting luminosities show IFRS to be similar to HzRGs, supporting our hypothesis. We found further evidence that fainter IFRS are at even higher redshifts. Conclusions: Considering the similarities between IFRS and HzRGs substantiated in this work, the detection of IFRS, which have a significantly higher sky density than HzRGs, increases the number of active galactic nuclei in the early universe and adds to the problems of explaining the formation of

  19. Solutions to the faint young Sun paradox simulated by a general circulation model

    NASA Astrophysics Data System (ADS)

    Wolf, Eric Theodore

    The faint young Sun paradox has dominated our thinking regarding early climate. Geological evidence abounds for warm, possibly hot, seawater temperatures and the proliferation of early life during the Archean period of Earth's history (3.8-2.5 Ga). However the standard solar model indicates that the Sun was only 75 to 82 percent as bright as today, implying an apparent contradiction between warm surface temperatures and weak solar irradiance. Geological evidence also places constraints on the amount of atmospheric carbon dioxide present early in Earth's history. Over the past four decades there has been much debate amongst geological, planetary, and climate science communities regarding how to properly resolve the issue of the faint young Sun. Up until very recently, 1-dimensional radiative convective models were the standard tool for deep paleoclimate modeling studies. These studies have notably lacked the ability to treat clouds, surface ice, and meridional energy transport. However, advancements in computing technology now allow us to tackle the faint young Sun paradox using a three-dimensional climate model. Here we use a modified version of the Community Atmosphere Model version 3 from the National Center for Atmospheric Research to study early climate. We find that resolving the faint young Sun paradox becomes less problematic when viewing a full representation of the climate system. Modest amounts of carbon dioxide and methane can provide adequate warming for the Archean within given constraints. Cooler climates with large ice caps but temperate tropical regions can be supported with even less carbon dioxide. The incorporation of systematic climate system differences expected during the Archean, such as fewer cloud condensation nuclei, reduced land albedos, and increased atmospheric nitrogen, can provide additional non-greenhouse means of warming the early Earth. A warm Archean no longer appears at odds with a faint young Sun. Here, we will also discuss the

  20. Syncope (Fainting)

    MedlinePlus

    ... associated with family history of recurrent syncope or sudden death What is neurally mediated syncope? Neurally mediated syncope ( ... is a genetic heart condition that can cause sudden cardiac death . Other tests , such as exercise stress test , Holter ...

  1. Red blood cell production

    MedlinePlus

    ... cells are an important element of blood. Their job is to transport oxygen to the body’s tissues in exchange for carbon dioxide, which is carried to and eliminated by the lungs. Red blood cells are formed in the red bone marrow of bones. Stem cells in the red bone marrow called hemocytoblasts ...

  2. RED-LETTER DAYS

    EPA Science Inventory

    The word "red-letter" is an adjective meaning "of special significance." It's origin is from the practice of marking Christian holy days in red letters on calendars. The "red-letter days" to which I refer occurred while I was a graduate student of ...

  3. International Federation of Red Cross and Red Crescent Societies

    MedlinePlus

    ... dignity and resilience Geneva, 14 September 2016 – The International Federation of Red Cross and Red Crescent Societies... ... News Contact us Sitemap Go to top The International Federation of Red Cross and Red Crescent Societies ( ...

  4. Variable Red Giants--The MACHO View

    SciTech Connect

    Keller, S C; Cook, K H

    2003-01-03

    The authors present a study of the MACHO red variable population in the Large Magellanic Cloud. This study reveals six period-luminosity relations among the red variable population. Only two of these were known prior to MACHO. The results are consistent with Mira pulsation in the fundamental mode. A sequence comprising 26% of the red variable population can not be explained by pulsation. They propose a dust {kappa}-mechanism in the circumstellar environment is responsible for the long period variation of these objects. The luminosity function of the variables shows a sharp edge at the tip of the red giant branch (TRGB). This is the first clear indication of a population of variable stars within the immediate vicinity of the TRGB. The results indicate this population amounts to 8% of the RGB population near the TRGB.

  5. The red and blue galaxy populations in the GOODS field: evidence for an excess of red dwarfs

    NASA Astrophysics Data System (ADS)

    Salimbeni, S.; Giallongo, E.; Menci, N.; Castellano, M.; Fontana, A.; Grazian, A.; Pentericci, L.; Trevese, D.; Cristiani, S.; Nonino, M.; Vanzella, E.

    2008-01-01

    Aims: We study the evolution of the galaxy population up to z˜ 3 as a function of its colour properties. In particular, luminosity functions and luminosity densities were derived as a function of redshift for the blue/late and red/early populations. Methods: We use data from the GOODS-MUSIC catalogue, which have typical magnitude limits z850≤ 26 and K_s≤ 23.5 for most of the sample. About 8% of the galaxies have spectroscopic redshifts; the remaining have well calibrated photometric redshifts derived from the extremely wide multi-wavelength coverage in 14 bands (from the U band to the Spitzer 8~ μm band). We have derived a catalogue of galaxies complete in the rest-frame B-band, which has been divided into two subsamples according to their rest-frame U-V colour (or derived specific star formation rate) properties. Results: We confirm a bimodality in the U-V colour and specific star formation rate of the galaxy sample up to z˜ 3. This bimodality is used to compute the luminosity functions of the blue/late and red/early subsamples. The luminosity functions of the blue/late and total samples are well represented by steep Schechter functions evolving in luminosity with increasing redshifts. The volume density of the luminosity functions of the red/early populations decreases with increasing redshift. The shape of the red/early luminosity functions shows an excess of faint red dwarfs with respect to the extrapolation of a flat Schechter function and can be represented by the sum of two Schechter functions. Our model for galaxy formation in the hierarchical clustering scenario, which also includes external feedback due to a diffuse UV background, shows a general broad agreement with the luminosity functions of both populations, the larger discrepancies being present at the faint end for the red population. Hints on the nature of the red dwarf population are given on the basis of their stellar mass and spatial distributions.

  6. Galaxy populations in the Antlia cluster - III. Properties of faint early-type galaxies

    NASA Astrophysics Data System (ADS)

    Smith Castelli, Analía. V.; Cellone, Sergio A.; Faifer, Favio R.; Bassino, Lilia P.; Richtler, Tom; Romero, Gisela A.; Calderón, Juan Pablo; Caso, Juan Pablo

    2012-01-01

    We present a new analysis of the early-type galaxy population in the central region of the Antlia cluster, focusing on the faint systems such as dwarf ellipticals (dEs) and dwarf spheroidals (dSphs). The colour-magnitude relation (CMR) and the relation between luminosity and mean effective surface brightness for galaxies in the central region of Antlia have been previously studied in Paper I of the present series. Now we confirm 22 early-type galaxies as Antlia members, using Gemini-GMOS and Magellan-MIKE spectra. Among them, 15 are dEs from the FS90 Antlia Group catalogue, two belong to the rare type of compact ellipticals (cEs) and five are new faint dwarfs that had never been catalogued before. In addition, we present 16 newly identified low-surface-brightness galaxy candidates, almost half of them displaying morphologies consistent with being Antlia's counterparts of Local Group dSphs, which extend the faint luminosity limit of our study down to MB=-10.1(BT= 22.6) mag. With these new data, we built an improved CMR in the Washington photometric system, i.e. integrated T1 magnitudes versus (C-T1) colours, which extends ˜4 mag faintwards the limit of spectroscopically confirmed Antlia members. When only confirmed early-type members are considered, this relation extends over 10 mag in luminosity with no apparent change in slope or increase in colour dispersion towards its faint end. The intrinsic colour scatter of the relation is compared with those reported for other clusters of galaxies; we argue that it is likely that the large scatter of the CMR, usually reported at faint magnitudes, is mostly due to photometric errors along with an improper membership/morphological classification. The distinct behaviour of the luminosity versus mean effective surface brightness relation at the bright and faint ends is analysed, while it is confirmed that dE galaxies on the same relation present a very similar effective radius, regardless of their colour. The projected spatial

  7. Variable Stars in the Field of the Hydra II Ultra-faint Dwarf Galaxy

    NASA Astrophysics Data System (ADS)

    Vivas, A. Katherina; Olsen, Knut; Blum, Robert; Nidever, David L.; Walker, Alistair R.; Martin, Nicolas F.; Besla, Gurtina; Gallart, Carme; van der Marel, Roeland P.; Majewski, Steven R.; Kaleida, Catherine C.; Muñoz, Ricardo R.; Saha, Abhijit; Conn, Blair C.; Jin, Shoko

    2016-05-01

    We report the discovery of one RR Lyrae star in the ultra-faint satellite galaxy Hydra II based on time series photometry in the g, r and i bands obtained with the Dark Energy Camera at Cerro Tololo Inter-American Observatory, Chile. The association of the RR Lyrae star discovered here with Hydra II is clear because is located at 42\\prime\\prime from the center of the dwarf, well within its half-light radius of 102\\prime\\prime . The RR Lyrae star has a mean magnitude of i=21.30+/- 0.04 which is too faint to be a field halo star. This magnitude translates to a heliocentric distance of 151 ± 8 kpc for Hydra II; this value is ∼ 13% larger than the estimate from the discovery paper based on the average magnitude of several blue horizontal branch star candidates. The new distance implies a slightly larger half-light radius of {76}-10+12 pc and a brighter absolute magnitude of {M}V=-5.1+/- 0.3, which keeps this object within the realm of the dwarf galaxies. A comparison with other RR Lyrae stars in ultra-faint systems indicates similar pulsational properties among them, which are different to those found among halo field stars and those in the largest of the Milky Way satellites. We also report the discovery of 31 additional short period variables in the field of view (RR Lyrae, SX Phe, eclipsing binaries, and a likely anomalous cepheid) which are likely not related with Hydra II.

  8. The Search for Faint Infrared Calibration Standards - Extending Landolt's Standards to V=19

    NASA Astrophysics Data System (ADS)

    Kidger, M.; González-Pérez, J. N.; Martín-Luis, F.; Cohen, M.

    ISO has shown the need to obtain a reliable calibration network of good pedigree to permit data from a wide range of instruments, covering an enormous wavelength range, to be calibrated on a consistent scale. We describe the first results of a programme to extend the Landolt calibration standards to at least V=19. At the same time we calibrate into the near-infrared JHK bands and measure fields separated from the celestial equator. This programme is one of several coordinated efforts to find faint type AV and KIII stars suitable for the mid-IR calibration of the Spanish 10-m Gran Telescopio Canarias (GTC). We have obtained a total of 34 712 measurements of 373 stars in 26 quasar fields between Declination -30o and +70o, calculating magnitudes with high precision in the visible and near-infrared (UBVRIJHK). We describe the results obtained and the characteristics of the sample of stars. The typical error on the magnitude in a single band is <1%, including all error sources. Very few candidate type AV or KIII stars are found, either in our sample, or amongst the fainter Landolt stars. We conclude that both samples are increasingly dominated by local dwarfs at increasingly faint magnitudes. We discuss the implications for taking mid-infrared calibration to the increasingly faint limits required by post-ISO instrumentation. The next steps in this project will be: -- To increase significantly the number of fields covered to ˜40. -- To take additional observations of all poorly covered fields and to add JHK data where none is available. -- To use our existing database to extend Landolt photometry of Selected Areas to include many stars not previously measured. -- To assign a spectral type to all candidate KIII and AV stars in our sample.

  9. Rocket instrument for far-UV spectrophotometry of faint astronomical objects.

    PubMed

    Hartig, G F; Fastie, W G; Davidsen, A F

    1980-03-01

    A sensitive sounding rocket instrument for moderate (~10-A) resolution far-UV (lambda1160-lambda1750-A) spectrophotometry of faint astronomical objects has been developed. The instrument employs a photon-counting microchannel plate imaging detector and a concave grating spectrograph behind a 40-cm Dall-Kirkham telescope. A unique remote-control pointing system, incorporating an SIT vidicon aspect camera, two star trackers, and a tone-encoded command telemetry link, permits the telescope to be oriented to within 5 arc sec of any target for which suitable guide stars can be found. The design, construction, calibration, and flight performance of the instrument are discussed. PMID:20220923

  10. Spectral evolution of galaxies. III - Cosmological predictions for the Space Telescope faint object camera

    NASA Astrophysics Data System (ADS)

    Bruzual A., G.

    1983-10-01

    The galactic spectral evolutionary models of Bruzual A. (1981) are employed to estimate parameters which will be observable by the wide-field camera and faint-object camera of the Space Telescope. The capabilities and bandpasses of the instruments are reviewed, and the results are presented in tables and graphs. Parameters calculated include the amplitude of the Lyman discontinuity at 912 A, stellar and galaxy rest-frame colors, color evolution, two-color diagrams as a function of redshift, luminosity evolution, surface brightness profiles, galaxy counts, and color and redshift distributions. In general, it is predicted that the space measurements will follow the trends noted in round-based observations.

  11. Polarimetry of the NGC 2261/R Monocerotis system and the faint jetlike feature to its southwest

    SciTech Connect

    Warren-Smith, R.F.; Draper, P.W.; Scarrott, S.M.

    1987-04-01

    Optical linear polarization maps of the region to the south of the NGC 2261/R Mon system show that the faint linear feature reported in 1985 by Walsh and Malin is reflection nebulosity directly illuminated by the star. The authors believe that it is the bright western rim of the highly obscured southern outflow from R Mon. The northern outflow, comprising the cometary nebular NGC 2261, shows polarization orientations that rotate with wavelength, deviating from the pattern expected in a simple reflection nebula. An explanation is offered involving an extensive magnetic field associated with the nebula, and the implications for magnetic acceleration of bipolar flows are discussed. 13 references.

  12. In-flight performance of the Faint Object Camera of the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Greenfield, P.; Paresce, F.; Baxter, D.; Hodge, P.; Hook, R.; Jakobsen, P.; Jedrzejewski, R.; Nota, A.; Sparks, W. B.; Towers, N.

    1991-01-01

    An overview of the Faint Object Camera and its performance to date is presented. In particular, the detector's efficiency, the spatial uniformity of response, distortion characteristics, detector and sky background, detector linearity, spectrography, and operation are discussed. The effect of the severe spherical aberration of the telescope's primary mirror on the camera's point spread function is reviewed, as well as the impact it has on the camera's general performance. The scientific implications of the performance and the spherical aberration are outlined, with emphasis on possible remedies for spherical aberration, hardware remedies, and stellar population studies.

  13. Faint-meteor survey with a large-format CMOS sensor

    NASA Astrophysics Data System (ADS)

    Watanabe, J.; Enomoto, T.; Terai, T.; Kasuga, T.; Miyazaki, S.; Oota, K.; Muraoka, F.; Onishi, T.; Yamasaki, T.; Mito, H.; Aoki, T.; Soyano, T.; Tarusawa, K.; Matsunaga, N.; Sako, S.; Kobayashi, N.; Doi, M.

    2014-07-01

    For observing faint meteors, we need a large telescope or similar optics, which always give a restriction of the field of view. It is a kind of trade-off between the high sensitivity by using larger telescope and narrower field of view. Reconciling this contradiction, we need a large-format imaging detector together with fast readout for meteor observations. A high-sensitivity CMOS sensor of the large format was developed by Canon Inc. in 2010[1]. Its size is 202 mm×205 mm which makes it the largest one-chip CMOS sensor in the world, and approximately 40 times the size of Canon's largest commercial CMOS sensor as shown in the figure. The number of pixel is 1280×1248. Because the increased size of the new CMOS sensor allows more light to be gathered, it enables shooting in low-light environments. The sensor makes image capture possible in one-hundredth the amount of light required by a 35 mm full-frame CMOS sensor, facilitating the shooting of 60 frame-per-second video with a mere 0.3 lux of illumination. We tried to use this large-format CMOS sensor attached to the prime focus of the 1.05-m (F3.1) Schmidt telescope at the Kiso Observatory, University of Tokyo, for surveying faint meteors. The field of view is 3.3 by 3.3 degrees. Test observations including operation check of the system were carried out in January 2011, September 2011,and December 2012. Images were obtained at a time resolution of 60 frames per second. In this system, the limiting magnitude is estimated to be about 11-12. Because of the limitation of the data storage, full-power observations (14-bit data per 1/60 second) were performed for about one or two hours each night. During the first period, we can count a sporadic meteor every 5 seconds. This is about one order higher detection rate of the faint meteors compared with the previous work[2]. Assuming the height of faint meteors at 100 km, the derived flux of the sporadic meteors is about 5 × 10^{-4} km^{-2} sec^{-1}. The last run was

  14. Evidence for Infrared-faint Radio Sources as z > 1 Radio-loud Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Huynh, Minh T.; Norris, Ray P.; Siana, Brian; Middelberg, Enno

    2010-02-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6-70 μm) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the spectral energy distribution of these objects shows that they are consistent with high-redshift (z >~ 1) active galactic nuclei.

  15. Infrared Faint Radio Sources in the Extended Chandra Deep Field South

    NASA Astrophysics Data System (ADS)

    Huynh, Minh T.

    2009-01-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey (ATLAS) which have no observable counterpart in the Spitzer Wide-area Infrared Extragalactic Survey (SWIRE). The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6 to 70 micron) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the SED of these objects shows that they are consistent with high redshift AGN (z > 2).

  16. Modified Theories of Gravity with Nonminimal Coupling and the Faint Young Sun Paradox

    NASA Astrophysics Data System (ADS)

    Iorio, Lorenzo

    2016-01-01

    A certain general class of modified gravitational theories with nonminimal coupling predicts a "pressure"-type, non-geodesic acceleration for a non-rotating, massive test particle. The resulting orbital perturbations for a two-body system consist of secular rates of change of all the standard orbital elements. The resulting variation of the mutual distance yields a physical mechanism which has the potential capability to explain, in principle, the Faint Young Sun Paradox in terms of a recession of the Earth from the Sun during the Archean.

  17. The early faint sun paradox: organic shielding of ultraviolet-labile greenhouse gases

    NASA Technical Reports Server (NTRS)

    Sagan, C.; Chyba, C.

    1997-01-01

    Atmospheric mixing ratios of approximately 10(-5 +/- 1) for ammonia on the early Earth would have been sufficient, through the resulting greenhouse warming, to counteract the temperature effects of the faint early sun. One argument against such model atmospheres has been the short time scale for ammonia photodissociation by solar ultraviolet light. Here it is shown that ultraviolet absorption by steady-state amounts of high-altitude organic solids produced from methane photolysis may have shielded ammonia sufficiently that ammonia resupply rates were able to maintain surface temperatures above freezing.

  18. Digital image profilers for detecting faint sources which have bright companions

    NASA Technical Reports Server (NTRS)

    Morris, Elena; Flint, Graham; Slavey, Robert

    1992-01-01

    For this program, an image profiling system was developed which offers the potential for detecting extremely faint optical sources that are located in close proximity to bright companions. The approach employed is novel in three respects. First, it does not require an optical system wherein extraordinary measures must be taken to minimize diffraction and scatter. Second, it does not require detectors possessing either extreme uniformity in sensitivity or extreme temporal stability. Finally, the system can readily be calibrated, or nulled, in space by testing against an unresolved singular stellar source.

  19. Rocket instrument for far-UV spectrophotometry of faint astronomical objects

    NASA Technical Reports Server (NTRS)

    Hartig, G. F.; Fastie, W. G.; Davidsen, A. F.

    1980-01-01

    A sensitive sounding rocket instrument for moderate (about 10-A) resolution far-UV (1160-1750-A) spectrophotometry of faint astronomical objects has been developed. The instrument employes a photon-counting microchannel plate imaging detector and a concave grating spectrograph behind a 40-cm Dall-Kirkham telescope. A unique remote-control pointing system, incorporating an SIT vidicon aspect camera, two star trackers, and a tone-encoded command telemetry link, permits the telescope to be oriented to within 5 arc sec of any target for which suitable guide stars can be found. The design, construction, calibration, and flight performance of the instrument are discussed.

  20. The Chandra Deep Survey of the Hubble Deep Field-North Area. II. Results from the Caltech Faint Field Galaxy Redshift Survey Area

    NASA Astrophysics Data System (ADS)

    Hornschemeier, A. E.; Brandt, W. N.; Garmire, G. P.; Schneider, D. P.; Barger, A. J.; Broos, P. S.; Cowie, L. L.; Townsley, L. K.; Bautz, M. W.; Burrows, D. N.; Chartas, G.; Feigelson, E. D.; Griffiths, R. E.; Lumb, D.; Nousek, J. A.; Ramsey, L. W.; Sargent, W. L. W.

    2001-06-01

    A deep X-ray survey of the Hubble Deep Field-North (HDF-N) and its environs is performed using data collected by the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-Ray Observatory. Currently a 221.9 ks exposure is available, the deepest ever presented, and here we give results on X-ray sources located in the 8.6‧×8.7‧ area covered by the Caltech Faint Field Galaxy Redshift Survey (the ``Caltech area''). This area has (1) deep photometric coverage in several optical and near-infrared bands; (2) extensive coverage at radio, submillimeter, and mid-infrared wavelengths; and (3) some of the deepest and most complete spectroscopic coverage ever obtained. It is also where the X-ray data have the greatest sensitivity; the minimum detectable fluxes in the 0.5-2 keV (soft) and 2-8 keV (hard) bands are ~1.3×10-16 and ~6.5×10-16 ergs cm-2 s-1, respectively. More than ~80% of the extragalactic X-ray background in the hard band is resolved. The 82 Chandra sources detected in the Caltech area are correlated with more than 25 multiwavelength source catalogs, and the results of these correlations as well as spectroscopic follow-up results obtained with the Keck and Hobby-Eberly Telescopes are presented. All but nine of the Chandra sources are detected optically with R<~26.5. Redshifts are available for 39% of the Chandra sources, including 96% of the sources with R<23 the redshift range is 0.1-3.5, with most sources having z<1.5. Eight of the X-ray sources are located in the HDF-N itself, including two not previously reported. A population of X-ray faint, optically bright, nearby galaxies emerges at soft-band fluxes of <~3×10-16 ergs cm-2 s-1. Our multiwavelength correlations have set the tightest constraints to date on the X-ray emission properties of μJy radio sources, mid-infrared sources detected by the Infrared Space Observatory (ISO), and very red (R-Ks>5.0) objects. A total of 16 of the 67 1.4 GHz μJy sources in the Caltech area are detected in the

  1. Red Marks the Spot

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This hematite abundance index map helps geologists choose hematite-rich locations to visit around Opportunity's landing site. Blue dots equal areas low in hematite and red dots equal areas high in hematite.

    Why Hematite Geologists are eager to reach the hematite-rich area in the upper left to closely examine the soil, which may reveal secrets about how the hematite got to this location. Knowing how the hematite on Mars was formed may help scientists characterize the past environment and determine whether that environment provided favorable conditions for life.

    The Plan Over the next few sols, engineers and scientists plan to drive Opportunity to the hematite-rich area then attempt a 'pre-trench' sequence, taking measurements with the Moessbauer spectrometer, alpha particle X-ray spectrometer and microscopic imager. Next, the plan is to trench the hematite rich area by spinning one wheel in place to 'dig' a shallow hole. Finally, scientists will aim the instrument arm back at the same area where it pre-trenched to get post-trench data with the same instruments to compare and contrast the levels of hematite and revel how deep the hematite lays in the dirt.

    Index Map Details The hematite abundance index map was created using data from the miniature thermal emission instrument. The first layer is a mosaic of panoramic camera images taken prior to egress, when Opportunity was still on the lander. The colored dots represent data collected by the miniature thermal emission spectrometer on sol 11, after Opportunity had rolled off of the lander and the rover was located at the center of the blue semi-circle.

    The spectrometer is located on the panoramic camera mast. On sol 11, it took a low-angle 180-degree panorama of the area in front of the rover, indicated by the blue shaded dots. The instrument then raised the angle of its field of view a few degrees higher to sweep around behind the rover, indicated by the red and yellow dots offset at the far sides of the

  2. THE INFRARED EYE OF THE WIDE-FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE REVEALS MULTIPLE MAIN SEQUENCES OF VERY LOW MASS STARS IN NGC 2808

    SciTech Connect

    Milone, A. P.; Aparicio, A.; Monelli, M. E-mail: aparicio@iac.es; and others

    2012-08-01

    We use images taken with the infrared channel of the Wide Field Camera 3 on the Hubble Space Telescope to study the multiple main sequences (MSs) of NGC 2808. Below the turnoff, the red, the middle, and the blue MS, previously detected from visual-band photometry, are visible over an interval of about 3.5 F160W magnitudes. The three MSs merge together at the level of the MS bend. At fainter magnitudes, the MS again splits into two components containing {approx}65% and {approx}35% of stars, with the most-populated MS being the bluest one. Theoretical isochrones suggest that the latter is connected to the red MS discovered in the optical color-magnitude diagram (CMD) and hence corresponds to the first stellar generation, having primordial helium and enhanced carbon and oxygen abundances. The less-populated MS in the faint part of the near-IR CMD is helium-rich and poor in carbon and oxygen, and it can be associated with the middle and the blue MS of the optical CMD. The finding that the photometric signature of abundance anti-correlation is also present in fully convective MS stars reinforces the inference that they have a primordial origin.

  3. A New Faint Milky Way Satellite Discovered in the Pan-STARRS1 3π Survey

    NASA Astrophysics Data System (ADS)

    Laevens, Benjamin P. M.; Martin, Nicolas F.; Ibata, Rodrigo A.; Rix, Hans-Walter; Bernard, Edouard J.; Bell, Eric F.; Sesar, Branimir; Ferguson, Annette M. N.; Schlafly, Edward F.; Slater, Colin T.; Burgett, William S.; Chambers, Kenneth C.; Flewelling, Heather; Hodapp, Klaus A.; Kaiser, Nicholas; Kudritzki, Rolf-Peter; Lupton, Robert H.; Magnier, Eugene A.; Metcalfe, Nigel; Morgan, Jeffrey S.; Price, Paul A.; Tonry, John L.; Wainscoat, Richard J.; Waters, Christopher

    2015-04-01

    We present the discovery of a faint Milky Way satellite, Laevens 2/Triangulum II, found in the Panoramic Survey Telescope And Rapid Response System 3π imaging data and confirmed with follow-up wide-field photometry from the Large Binocular Cameras. The stellar system, with an absolute magnitude of MV = -1.8 ± 0.5, a heliocentric distance of 30-2+2 kpc, and a half-mass-radius of 34-8+9 pc, shows remarkable similarity to faint, nearby, small satellites such as Willman 1, Segue 1, Segue 2, and Boötes II. The discovery of Laevens 2/Triangulum II further populates the region of parameter space for which the boundary between dwarf galaxies and globular clusters becomes tenuous. Follow-up spectroscopy will ultimately determine the nature of this new satellite, whose spatial location hints at a possible connection with the complex Triangulum-Andromeda stellar structures. The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are The University of Arizona on behalf of the Arizona university system; Instituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

  4. Searching for Faint Companions to Nearby Stars with the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Schroeder, Daniel J.; Golimowski, David A.

    1996-01-01

    A search for faint companions (FC's) to selected stars within 5 pc of the Sun using the Hubble Space Telescope's Planetary Camera (PC) has been initiated. To assess the PC's ability to detect FCs, we have constructed both model and laboratory-simulated images and compared them to actual PC images. We find that the PC's point-spread function (PSF) is 3-4 times brighter over the angular range 2-5 sec than the PSF expected for a perfect optical system. Azimuthal variations of the PC's PSF are 10-20 times larger than expected for a perfect PSF. These variations suggest that light is scattered nonuniformly from the surface of the detector. Because the anomalies in the PC's PSF cannot be precisely simulated, subtracting a reference PSF from the PC image is problematic. We have developed a computer algorithm that identifies local brightness anomalies within the PSF as potential FCs. We find that this search algorithm will successfully locate FCs anywhere within the circumstellar field provided that the average pixel signal from the FC is at least 10 sigma above the local background. This detection limit suggests that a comprehensive search for extrasolar Jovian planets with the PC is impractical. However, the PC is useful for detecting other types of substellar objects. With a stellar signal of 10(exp 9) e(-), for example, we may detect brown dwarfs as faint as M(sub I) = 16.7 separated by 1 sec from alpha Cen A.

  5. Star/galaxy separation at faint magnitudes: Application to a simulated Dark Energy Survey

    SciTech Connect

    Soumagnac, M.T.; et al.

    2013-06-21

    We address the problem of separating stars from galaxies in future large photometric surveys. We focus our analysis on simulations of the Dark Energy Survey (DES). In the first part of the paper, we derive the science requirements on star/galaxy separation, for measurement of the cosmological parameters with the Gravitational Weak Lensing and Large Scale Structure probes. These requirements are dictated by the need to control both the statistical and systematic errors on the cosmological parameters, and by Point Spread Function calibration. We formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier. In order to achieve these requirements at faint magnitudes, we propose a new method for star/galaxy separation in the second part of the paper. We first use Principal Component Analysis to outline the correlations between the objects parameters and extract from it the most relevant information. We then use the reduced set of parameters as input to an Artificial Neural Network. This multi-parameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SExtractor), especially at faint magnitudes: it increases the purity by up to 20% for stars and by up to 12% for galaxies, at i-magnitude fainter than 23.

  6. Observations of faint comets at McDonald Observatory: 1978-1980

    NASA Technical Reports Server (NTRS)

    Barker, E. S.; Cochran, A. L.; Rybski, P. M.

    1981-01-01

    Modern observational techniques, developed for spectroscopy and photometry of faint galaxies and quasars, successfully applied to faint comets on the 2.7 m telescope. The periodic comets Van Biesbrock, Ashbrook-Jackson, Schwassmann-Wachmann 1, Tempel 2, Encke, Forbes, Brooks 2, Stephan-Oterma and the new comets Bradfield (19791), Bowell (1980b), Chernis-Petrauskas (1980k) were observed. The comets ranged in magnitude from 10th to 20th magnitude. For comets fainter than 19th magnitude, reflectance spectra at 100A resolution and area photometry were obtained. On comets of 17th or 18th magnitude, spectrometric scans (6A resolution) of the nucleus or inner coma region. On those comets which are brighter than 16th magnitude spatial spectrophotometric (6A resolution) studies of the inner and extended comae were done. An extensive spatial study of the comae of P/Encke and P/Stephen-Oterma, correlated with heliocentric distance is taking place. The observing process used is described and examples of the results obtained to date are discussed.

  7. Discovery of a New Photometric Sub-class of Faint and Fast Classical Novae

    NASA Astrophysics Data System (ADS)

    Kasliwal, M. M.; Cenko, S. B.; Kulkarni, S. R.; Ofek, E. O.; Quimby, R.; Rau, A.

    2011-07-01

    We present photometric and spectroscopic follow-up of a sample of extragalactic novae discovered by the Palomar 60 inch telescope during a search for "Fast Transients In Nearest Galaxies" (P60-FasTING). Designed as a fast cadence (1 day) and deep (g < 21 mag) survey, P60-FasTING was particularly sensitive to short-lived and faint optical transients. The P60-FasTING nova sample includes 10 novae in M 31, 6 in M 81, 3 in M 82, 1 in NGC 2403, and 1 in NGC 891. This significantly expands the known sample of extragalactic novae beyond the Local Group, including the first discoveries in a starburst environment. Surprisingly, our photometry shows that this sample is quite inconsistent with the canonical maximum-magnitude-rate-of-decline (MMRD) relation for classical novae. Furthermore, the spectra of the P60-FasTING sample are indistinguishable from classical novae. We suggest that we have uncovered a sub-class of faint and fast classical novae in a new phase space in luminosity-timescale of optical transients. Thus, novae span two orders of magnitude in both luminosity and time. Perhaps the MMRD, which is characterized only by the white dwarf mass, was an oversimplification. Nova physics appears to be characterized by a relatively rich four-dimensional parameter space in white dwarf mass, temperature, composition, and accretion rate.

  8. Faint blue counts from formation of dwarf galaxies at z approximately equals 1

    NASA Technical Reports Server (NTRS)

    Babul, Arif; Rees, Martin J.

    1993-01-01

    The nature of faint blue objects (FBO's) has been a source of much speculation since their detection in deep CCD images of the sky. Their high surface density argues against them being progenitors of present-day bright galaxies and since they are only weakly clustered on small scales, they cannot be entities that merged together to form present-day galaxies. Babul & Rees (1992) have suggested that the observed faint blue counts may be due to dwarf elliptical galaxies undergoing their initial starburst at z is approximately equal to 1. In generic hierarchical clustering scenarios, however, dwarf galaxy halos (M is approximately 10(exp 9) solar mass) are expected to form at an earlier epoch; for example, typical 10(exp 9) solar mass halos will virialize at z is approximately equal to 2.3 if the power-spectrum for the density fluctuations is that of the standard b = 2 cold dark matter (CDM) model. Under 'ordinary conditions' the gas would rapidly cool, collect in the cores, and undergo star-formation. Conditions at high redshifts are far from 'ordinary'. The intense UV background will prevent the gas in the dwarf halos from cooling, the halos being released from their suspended state only when the UV flux has diminished sufficiently.

  9. Biomediated Precipitation of Calcium Carbonate and Sulfur in a Faintly Acidic Hot Spring

    NASA Astrophysics Data System (ADS)

    Jiang, L.; Peng, X.; Qiao, H.

    2014-12-01

    A faintly acidic hot spring named "female Tower" (T=73.5 ℃, pH=6.64 ) is located in the Jifei Geothermal Field,Yunnan province, Southwest China. The precipitates in the hot spring are composed of large amounts of calcite and sulfur, as reveals by XRD analysis. Scanning electron microscopy (SEM) analysis show the microbial mats are formed of various coccoid, rod and filamentous microbes. Transmission electron microscopy (TEM) analysis show that intracellular sulfur granules are commonly associated with these microbes. Energy dispersive X-ray spectrometer (EDS) analysis shows that the surface of microbes are mainly composed of Ca, C, O and S. A culture-independent molecular phylogenetic analysis demonstrates the majority of bacteria in the spring are sulfur-oxidizing bacteria. In the spring water, H2S concentration was up to 60 ppm, while SO42- concentration was only about 10 ppm. We suggest that H2S might be utilized by sulfur-oxidizing bacteria in this hot spring water, leading to the formation of sulfur granules intracellularly and extracellularly. In the meantime, this reaction increases the pH in ambient environments, which fosters the precipitation of calcium carbonate precipitation in the microbial mats. This study suggests that the sulfur-oxidizing bacteria could play an important role in calcium carbonate precipitation in faintly acidic hot spring environments.

  10. STELLAR ARCHEOLOGY IN THE GALACTIC HALO WITH ULTRA-FAINT DWARFS. VII. HERCULES

    SciTech Connect

    Musella, Ilaria; Ripepi, Vincenzo; Marconi, Marcella E-mail: ripepi@na.astro.it; and others

    2012-09-10

    We present the first time-series study of the ultra-faint dwarf galaxy Hercules. Using a variety of telescope/instrument facilities we secured about 50 V and 80 B epochs. These data allowed us to detect and characterize 10 pulsating variable stars in Hercules. Our final sample includes six fundamental-mode (ab-type) and three first-overtone (c-type) RR Lyrae stars, and one Anomalous Cepheid. The average period of the ab-type RR Lyrae stars, (P{sub ab}) = 0.68 days ({sigma} = 0.03 days), places Hercules in the Oosterhoff II group, as found for almost the totality of the ultra-faint dwarf galaxies investigated so far for variability. The RR Lyrae stars were used to obtain independent estimates of the metallicity, reddening, and distance to Hercules, for which we find [Fe/H] = -2.30 {+-} 0.15 dex, E(B - V) = 0.09 {+-} 0.02 mag, and (m - M){sub 0} = 20.6 {+-} 0.1 mag, in good agreement with the literature values. We have obtained a V, B - V color-magnitude diagram (CMD) of Hercules that reaches V {approx} 25 mag and extends beyond the galaxy's half-light radius over a total area of 40' Multiplication-Sign 36'. The CMD and the RR Lyrae stars indicate the presence of a population as old and metal-poor as (at least) the Galactic globular cluster M68.

  11. THE DISCOVERY OF AN ULTRA-FAINT STAR CLUSTER IN THE CONSTELLATION OF URSA MINOR

    SciTech Connect

    Munoz, R. R.; Geha, M.; Vargas, L. C.; Cote, P.; Stetson, P.; Santana, F. A.; Simon, J. D.; Djorgovski, S. G.

    2012-07-01

    We report the discovery of a new ultra-faint globular cluster in the constellation of Ursa Minor, based on stellar photometry from the MegaCam imager at the Canada-France-Hawaii Telescope. We find that this cluster, Munoz 1, is located at a distance of 45 {+-} 5 kpc and at a projected distance of only 45' from the center of the Ursa Minor dwarf spheroidal galaxy. Using a maximum-likelihood technique we measure a half-light radius of 0.'5, or equivalently 7 pc, and an ellipticity consistent with being zero. We estimate its absolute magnitude to be M{sub V} -0.4 {+-} 0.9, which corresponds to L{sub V} = 120{sup +160}{sub -65} L{sub Sun} and we measure a heliocentric radial velocity of -137 {+-} 4 km s{sup -1} based on Keck/DEIMOS spectroscopy. This new satellite is separate from Ursa Minor by {approx}30 kpc and 110 km s{sup -1} suggesting the cluster is not obviously associated with the dSph, despite the very close angular separation. Based on its photometric properties and structural parameters we conclude that Munoz 1 is a new ultra-faint stellar cluster. Along with Segue 3 this is one of the faintest stellar clusters known to date.

  12. Star/galaxy separation at faint magnitudes: application to a simulated Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Soumagnac, M. T.; Abdalla, F. B.; Lahav, O.; Kirk, D.; Sevilla, I.; Bertin, E.; Rowe, B. T. P.; Annis, J.; Busha, M. T.; Da Costa, L. N.; Frieman, J. A.; Gaztanaga, E.; Jarvis, M.; Lin, H.; Percival, W. J.; Santiago, B. X.; Sabiu, C. G.; Wechsler, R. H.; Wolz, L.; Yanny, B.

    2015-06-01

    We address the problem of separating stars from galaxies in future large photometric surveys. We focus our analysis on simulations of the Dark Energy Survey (DES). In the first part of the paper, we derive the science requirements on star/galaxy separation, for measurement of the cosmological parameters with the gravitational weak lensing and large-scale structure probes. These requirements are dictated by the need to control both the statistical and systematic errors on the cosmological parameters, and by point spread function calibration. We formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier. In order to achieve these requirements at faint magnitudes, we propose a new method for star/galaxy separation in the second part of the paper. We first use principal component analysis to outline the correlations between the objects parameters and extract from it the most relevant information. We then use the reduced set of parameters as input to an Artificial Neural Network. This multiparameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SEXTRACTOR), especially at faint magnitudes: it increases the purity by up to 20 per cent for stars and by up to 12 per cent for galaxies, at i-magnitude fainter than 23.

  13. DISCOVERY OF A NEW PHOTOMETRIC SUB-CLASS OF FAINT AND FAST CLASSICAL NOVAE

    SciTech Connect

    Kasliwal, M. M.; Kulkarni, S. R.; Ofek, E. O.; Quimby, R.; Cenko, S. B.; Rau, A.

    2011-07-10

    We present photometric and spectroscopic follow-up of a sample of extragalactic novae discovered by the Palomar 60 inch telescope during a search for 'Fast Transients In Nearest Galaxies' (P60-FasTING). Designed as a fast cadence (1 day) and deep (g < 21 mag) survey, P60-FasTING was particularly sensitive to short-lived and faint optical transients. The P60-FasTING nova sample includes 10 novae in M 31, 6 in M 81, 3 in M 82, 1 in NGC 2403, and 1 in NGC 891. This significantly expands the known sample of extragalactic novae beyond the Local Group, including the first discoveries in a starburst environment. Surprisingly, our photometry shows that this sample is quite inconsistent with the canonical maximum-magnitude-rate-of-decline (MMRD) relation for classical novae. Furthermore, the spectra of the P60-FasTING sample are indistinguishable from classical novae. We suggest that we have uncovered a sub-class of faint and fast classical novae in a new phase space in luminosity-timescale of optical transients. Thus, novae span two orders of magnitude in both luminosity and time. Perhaps the MMRD, which is characterized only by the white dwarf mass, was an oversimplification. Nova physics appears to be characterized by a relatively rich four-dimensional parameter space in white dwarf mass, temperature, composition, and accretion rate.

  14. A multifrequency radio continuum and IRAS faint source survey of markarian galaxies

    NASA Technical Reports Server (NTRS)

    Bicay, M. D.; Kojoian, G.; Seal, J.; Dickinson, D. F.; Malkan, M. A.

    1995-01-01

    Results are presented from a multifrequency radio continumm survey of Markarian galaxies (MRKs) and are supplemented by IRAS infrared data from the Faint Source Survey. Radio data are presented for 899 MRKs observed at nu = 4.755 GHz with the National Radio Astronomy Observatory (NRAO)-Green Bank 300 foot (91 m) telescope, including nearly 88% of those objects in Markarian lists VI-XIV. In addition, 1.415 GHz measurements of 258 MRKs, over 30% of the MRKs accessible from the National Aeronomy and Ionosphere Center (NAIC)-Arecibo, are reported. Radio continuum observations of smaller numbers of MRKs were made at 10.63 GHz and at 23.1 GHz and are also presented. Infrared data from the IRAS Faint Source Survey (Ver. 2) are presented for 944 MRKs, with reasonably secure identifications extracted from the NASA/IPAC Extragalactic Database. MRKs exhibit the same canonical infrared characteristics as those reported for various other galaxy samples, that is well-known enhancement of the 25 micrometer/60 micrometer color ratio among Seyfert MRKs, and a clear tendency for MRKs with warmer 60 micrometer/100 micrometer colors to also possess cooler 12 micrometer/25 micrometer colors. In addition, non-Seyfert are found to obey the well-documented infrared/radio luminosity correlation, with the tightest correlation seen for starburst MRKs.

  15. The Detection of Ultra-faint Low Surface Brightness Dwarf Galaxies in the Virgo Cluster: A Probe of Dark Matter and Baryonic Physics

    NASA Astrophysics Data System (ADS)

    Giallongo, E.; Menci, N.; Grazian, A.; Fassbender, R.; Fontana, A.; Paris, D.; Pentericci, L.

    2015-11-01

    We have discovered 11 ultra-faint (r ≲ 22.1) low surface brightness (LSB, central surface brightness 23 ≲ μr ≲ 26) dwarf galaxy candidates in one deep Virgo field of just 576 arcmin2 obtained by the Large Binocular Camera at the Large Binocular Telescope. Their association with the Virgo cluster is supported by their distinct position in the central surface brightness—total magnitude plane with respect to the background galaxies of similar total magnitude. They have typical absolute magnitudes and scale sizes, if at the distance of Virgo, in the range -13 ≲ Mr ≲ -9 and 250 ≲ rs ≲ 850 pc, respectively. Their colors are consistent with a gradually declining star formation history with a specific star formation rate of the order of 10-11 yr-1, i.e., 10 times lower than that of main sequence star-forming galaxies. They are older than the cluster formation age and appear to be regular in morphology. They represent the faintest extremes of the population of low luminosity LSB dwarfs that has recently been detected in wider surveys of the Virgo cluster. Thanks to the depth of our observations, we are able to extend the Virgo luminosity function down to Mr ˜ -9.3 (corresponding to total masses M ˜ 107 M⊙), finding an average faint-end slope α ≃ -1.4. This relatively steep slope puts interesting constraints on the nature of the dark matter and, in particular, on warm dark matter (WDM) often invoked to solve the overprediction of the dwarf number density by the standard cold dark matter scenario. We derive a lower limit on the WDM particle mass >1.5 keV.

  16. Using Green and Red Fluorescent Proteins to Teach Protein Expression, Purification, and Crystallization

    ERIC Educational Resources Information Center

    Wu, Yifeng; Zhou, Yangbin; Song, Jiaping; Hu, Xiaojian; Ding, Yu; Zhang, Zhihong

    2008-01-01

    We have designed a laboratory curriculum using the green and red fluorescent proteins (GFP and RFP) to visualize the cloning, expression, chromatography purification, crystallization, and protease-cleavage experiments of protein science. The EGFP and DsRed monomer (mDsRed)-coding sequences were amplified by PCR and cloned into pMAL (MBP-EGFP) or…

  17. Improving the ability of image sensors to detect faint stars and moving objects using image deconvolution techniques.

    PubMed

    Fors, Octavi; Núñez, Jorge; Otazu, Xavier; Prades, Albert; Cardinal, Robert D

    2010-01-01

    In this paper we show how the techniques of image deconvolution can increase the ability of image sensors as, for example, CCD imagers, to detect faint stars or faint orbital objects (small satellites and space debris). In the case of faint stars, we show that this benefit is equivalent to double the quantum efficiency of the used image sensor or to increase the effective telescope aperture by more than 30% without decreasing the astrometric precision or introducing artificial bias. In the case of orbital objects, the deconvolution technique can double the signal-to-noise ratio of the image, which helps to discover and control dangerous objects as space debris or lost satellites. The benefits obtained using CCD detectors can be extrapolated to any kind of image sensors. PMID:22294896

  18. Faint meteor observation by large-format CMOS sensor with 1.05-m Kiso schmidt telescope

    NASA Astrophysics Data System (ADS)

    Watanabe, J.; Kasuga, T.; Terai, T.; Miyazaki, S.; Ohta, K.; Murooka, F.; Ohnishi, T.; Yamasaki, T.; Mito, H.; Aoki, T.; Soyano, T.; Tarusawa, K.; Matsunaga, N.; Sako, S.; Kobayashi, N.; Doi, M.; Enomoto, T.

    2014-07-01

    We tried to use a new high-sensitivity CMOS sensor of the world's largest size as a one-chip 20cmx 20cm square attached to the prime focus of the 1.05 m (F3.1) Schmidt telescope at the Kiso Observatory, University of Tokyo, for faint meteor observation. The resulting field of view was 3.3 by 3.3 degrees, with a limiting magnitude of about 12 in our preliminary analysis. Assuming the height of faint meteors at 100 km, the derived flux of sporadic meteors is about 5x10^{-4} km^{-2}s^{-1}. Although the analysis is still on going, it is clear that this CMOS sensor is useful and effective for observing faint meteors.

  19. Improving the Ability of Image Sensors to Detect Faint Stars and Moving Objects Using Image Deconvolution Techniques

    PubMed Central

    Fors, Octavi; Núñez, Jorge; Otazu, Xavier; Prades, Albert; Cardinal, Robert D.

    2010-01-01

    In this paper we show how the techniques of image deconvolution can increase the ability of image sensors as, for example, CCD imagers, to detect faint stars or faint orbital objects (small satellites and space debris). In the case of faint stars, we show that this benefit is equivalent to double the quantum efficiency of the used image sensor or to increase the effective telescope aperture by more than 30% without decreasing the astrometric precision or introducing artificial bias. In the case of orbital objects, the deconvolution technique can double the signal-to-noise ratio of the image, which helps to discover and control dangerous objects as space debris or lost satellites. The benefits obtained using CCD detectors can be extrapolated to any kind of image sensors. PMID:22294896

  20. Red Clover Breeding Progress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red clover (Trifolium pratense L.) is an important forage legume grown on approximately 4 million hectares worldwide. It has a long and varied history in agriculture. Active breeding efforts began at the end of the 19th century. Since this time significant improvement in red clover cultivar for a...

  1. Cobb's Red Cabbage Indicator.

    ERIC Educational Resources Information Center

    Cobb, Vicki

    1998-01-01

    Describes the use of an indicator made from the pigment in red cabbage. Cabbage is grated then soaked in water. When the water is a strong red, the cabbage is strained out. The cabbage-juice indicator is then used to test for acids and bases. Includes a list of good foods to test for acidity and alkalinity. (PVD)

  2. Jupiter's Great Red spot

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This color composite made from Voyager 2 narrow-angle camera frames shows the Great Red Spot during the late Jovian afternoon. North of the Red Spot lies a curious darker section of the South Equatorial Belt (SEB), the belt in which the Red Spot is located. A bright eruption of material passing from the SEB northward into the diffuse equatorial clouds has been observed on all occasions when this feature passes north of the Red Spot. The remnants of one such eruption are apparent in this photograph. To the lower left of the Red Spot lies one of the three long-lived White Ovals. This photograph was taken on June 29, 1979, when Voyager 2 was over 9 million kilometers (nearly 6 million miles) from Jupiter. The smallest features visible are over 170 kilometers (106 miles) across.

  3. Faint disks around classical T Tauri stars: Small but dense enough to form planets

    NASA Astrophysics Data System (ADS)

    Piétu, V.; Guilloteau, S.; Di Folco, E.; Dutrey, A.; Boehler, Y.

    2014-04-01

    Context. Most Class II sources (of nearby star-forming regions) are surrounded by disks with weak millimeter continuum emission. These "faint" disks may hold clues to the disk dissipation mechanism. However, the physical properties of protoplanetary disks have been directly constrained by imaging only the brightest sources. Aims: We attempt to determine the characteristics of such faint disks around classical T Tauri stars and to explore the link between disk faintness and the proposed disk dispersal mechanisms (accretion, viscous spreading, photo-evaporation, planetary system formation). Methods: We performed high angular resolution (0.3'') imaging of a small sample of disks (9 sources) with low 1.3 mm continuum flux (mostly <30 mJy) with the IRAM Plateau de Bure interferometer and simultaneously searched for 13CO (or CO) J = 2-1 line emission. Using a simple parametric disk model, we determined characteristic sizes for the disks in dust and gas, and we constrained surface densities in the central 50 AU. Results: All disks are much smaller than the bright disks imaged so far, both in continuum and 13CO lines (5 detections). In continuum, half of the disks are very small, with characteristic radii less than 10 AU, but still have high surface density values. Small sizes appear to be the main cause of the low disk luminosity. Direct evidence for grain growth is found for the three disks that are sufficiently resolved. Low continuum opacity is attested in only two systems, but we cannot firmly distinguish between a low gas surface density and a lower dust emissivity resulting from grain growth. Finally, we report a tentative discovery of a ~20 AU radius cavity in DS Tau, which with the (unresolved) "transition" disk of CX Tau, brings the proportion of "transitional" disks to a similar value to that of brighter sources. The existence of cavities cannot by itself explain their observed low mm flux. Conclusions: This study highlights a category of very compact dust disks

  4. THE FAINT-END SLOPE OF THE REDSHIFT 5.7 Ly{alpha} LUMINOSITY FUNCTION

    SciTech Connect

    Henry, Alaina L.; Martin, Crystal L.; Dressler, Alan; McCarthy, Patrick; Sawicki, Marcin

    2012-01-10

    Using new Keck DEIMOS spectroscopy, we examine the origin of the steep number counts of ultra-faint emission-line galaxies recently reported by Dressler et al. We confirm six Ly{alpha} emitters (LAEs), three of which have significant asymmetric line profiles with prominent wings extending 300-400 km s{sup -1} redward of the peak emission. With these six LAEs, we revise our previous estimate of the number of faint LAEs in the Dressler et al. survey. Combining these data with the density of bright LAEs in the Cosmic Evolution Survey and Subaru Deep Field provides the best constraints to date on the redshift 5.7 LAE luminosity function (LF). Schechter function parameters, {phi}* = 4.5 Multiplication-Sign 10{sup -4} Mpc{sup -3}, L* = 9.1 Multiplication-Sign 10{sup 42} erg s{sup -1}, and {alpha} = -1.70, are estimated using a maximum likelihood technique with a model for slit-losses. To place this result in the context of the UV-selected galaxy population, we investigate how various parameterizations of the Ly{alpha} equivalent width distribution, along with the measured UV-continuum LF, affect shape and normalization of the Ly{alpha} LF. The nominal model, which uses z {approx} 6 equivalent widths from the literature, falls short of the observed space density of LAEs at the bright end, possibly indicating a need for higher equivalent widths. This parameterization of the equivalent width distribution implies that as many as 50% of our faintest LAEs should have M{sub UV} > -18.0, rendering them undetectable in even the deepest Hubble Space Telescope surveys at this redshift. Hence, ultra-deep emission-line surveys find some of the faintest galaxies ever observed at the end of the reionization epoch. Such faint galaxies likely enrich the intergalactic medium with metals and maintain its ionized state in the post-reionization era. Observations of these objects provide a glimpse of the building blocks of present-day galaxies at an early time.

  5. Toward a Network of Faint DA White Dwarfs as High-precision Spectrophotometric Standards

    NASA Astrophysics Data System (ADS)

    Narayan, G.; Axelrod, T.; Holberg, J. B.; Matheson, T.; Saha, A.; Olszewski, E.; Claver, J.; Stubbs, C. W.; Bohlin, R. C.; Deustua, S.; Rest, A.

    2016-05-01

    We present the initial results from a program aimed at establishing a network of hot DA white dwarfs to serve as spectrophotometric standards for present and future wide-field surveys. These stars span the equatorial zone and are faint enough to be conveniently observed throughout the year with large-aperture telescopes. The spectra of these white dwarfs are analyzed in order to generate a non-local-thermodynamic-equilibrium model atmosphere normalized to Hubble Space Telescope colors, including adjustments for wavelength-dependent interstellar extinction. Once established, this standard star network will serve ground-based observatories in both hemispheres as well as space-based instrumentation from the UV to the near IR. We demonstrate the effectiveness of this concept and show how two different approaches to the problem using somewhat different assumptions produce equivalent results. We discuss the lessons learned and the resulting corrective actions applied to our program.

  6. Two New Ultra-Faint Star Clusters in the Milky Way Halo

    NASA Astrophysics Data System (ADS)

    Kim, Dongwon

    2016-08-01

    Kim 1 & 2 are two new star clusters discovered in the Stromlo Missing Satellite Survey. Kim 1, located at a heliocentric distance of 19.8 +/- 0.9 kpc, features an extremely low total luminosity (M V = 0.3 +/- 0.5 mag) and low star concentration. Together with the large ellipticity (ɛ = 0.42 +/- 0.10) and irregular isophotes, these properties suggest that Kim 1 is an intermediate mass star cluster being stripped by the Galactic tidal field. Kim 2 is a rare ultra-faint outer halo globular cluster located at a heliocentric distance of 104.7 +/- 4.1 kpc. The cluster exhibits evidence of significant mass loss such as extra-tidal stars and mass-segregation. Kim 2 is likely to follow an orbit confined to the peripheral region of the Galactic halo, and/or to have formed in a dwarf galaxy that was later accreted into the Galactic halo.

  7. Cosmic Reionization on Computers: The Faint End of the Galaxy Luminosity Function

    NASA Astrophysics Data System (ADS)

    Gnedin, Nickolay Y.

    2016-07-01

    Using numerical cosmological simulations completed under the “Cosmic Reionization On Computers” project, I explore theoretical predictions for the faint end of the galaxy UV luminosity functions at z≳ 6. A commonly used Schechter function approximation with the magnitude cut at {M}{{cut}}˜ -13 provides a reasonable fit to the actual luminosity function of simulated galaxies. When the Schechter functional form is forced on the luminosity functions from the simulations, the magnitude cut {M}{{cut}} is found to vary between ‑12 and ‑14 with a mild redshift dependence. An analytical model of reionization from Madau et al., as used by Robertson et al., provides a good description of the simulated results, which can be improved even further by adding two physically motivated modifications to the original Madau et al. equation.

  8. Faint X-Ray Structure in the Crab Pulsar Wind Nebula

    NASA Astrophysics Data System (ADS)

    Seward, F. D.; Tucker, W. H.; Fesen, R. A.

    2006-12-01

    We report on a Chandra observation of the Crab Nebula that gives the first clear view of the faint boundary of the Crab's X-ray-emitting pulsar wind nebula. There is structure in all directions. Fingers, loops, bays, and the south pulsar jet all indicate that either filamentary material or the magnetic field is controlling the relativistic electrons. In general, spectra soften as distance from the pulsar increases but do not change rapidly along linear features. This is particularly true for the pulsar jet. The termination of the jet is abrupt; the east side is close to an [O III] optical filament, which may be blocking propagation on this side. We argue that linear features have ordered magnetic fields and that the structure is determined by the synchrotron lifetime of particles diffusing perpendicular and parallel to the magnetic field. We find no significant evidence for thermal X-rays inside the filamentary envelope.

  9. GT2_ncox_1: Faint Extended Dust Envelopes of Young Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Cox, N.

    2011-05-01

    We propose to trace the distribution of cold dust in the extended envelopes of a selected sample of young Planetary Nebulae (PNe). Information on the mass-loss and overall envelope ejection process of Asymptotic Giant Branch (AGB) stars is imprinted in the morphology of the extended dust shells formed throughout the AGB phase. In particular the origin of asymmetrical PN shapes and their relation to spherical mass-loss presumed to occur on the AGB phase can be illuminated upon. We propose to use PACS to follow-up on AKARI/FIS observations of young PNe to study their mass-loss history. Only Herschel's unprecedented spatial resolution and sensitivity in the far-IR can detect the faint extended cold dust emission in these objects.

  10. Cosmic reionization on computers: The faint end of the galaxy luminosity function

    DOE PAGESBeta

    Gnedin, Nickolay Y.

    2016-07-01

    Using numerical cosmological simulations completed under the “Cosmic Reionization On Computers” project, I explore theoretical predictions for the faint end of the galaxy UV luminosity functions atmore » $$z\\gtrsim 6$$. A commonly used Schechter function approximation with the magnitude cut at $${M}_{{\\rm{cut}}}\\sim -13$$ provides a reasonable fit to the actual luminosity function of simulated galaxies. When the Schechter functional form is forced on the luminosity functions from the simulations, the magnitude cut $${M}_{{\\rm{cut}}}$$ is found to vary between -12 and -14 with a mild redshift dependence. Here, an analytical model of reionization from Madau et al., as used by Robertson et al., provides a good description of the simulated results, which can be improved even further by adding two physically motivated modifications to the original Madau et al. equation.« less

  11. Faint quasi-stellar-object candidates in selected areas 28 and 68 identified from multicolor photometry

    SciTech Connect

    Shields, J.C.; Koo, D.C.; Kron, R.C.; California Univ., Berkeley; Lick Observatory, Santa Cruz, CA; Yerkes Observatory, Williams Bay, WI )

    1989-04-01

    Forty-five QSO candidates over a total area of 0.53 square degree in two fields at high Galactic latitudes have been identified. These candidates reached B of about 21.5 for field Lynx.3 in SA 28 and B of about 22 for field SA68.2, and were selected from a subset of objects in catalogs generated from multicolor photometry (UBV) of deep Kitt Peak 4-m plates with limits of B of about 24. This subset consists of all objects which appeared stellar-like in size but which did not have the UBV colors of common Galactic stars. Besides several probable high-redshift QSOs, this study yields faint QSO counts consistent with those from other surveys, and thus provides further support to models that include mainly the luminosity evolution of QSOs. 29 refs.

  12. Indirect Dark Matter Detection Limits from the Ultra-Faint Milky Way Satellite Segue 1

    SciTech Connect

    Essig, Rouven; Sehgal, Neelima; Strigari, Louis E.; Geha, Marla; Simon, Joshua D.; /Carnegie Inst. Observ.

    2011-08-11

    We use new kinematic data from the ultra-faint Milky Way satellite Segue 1 to model its dark matter distribution and derive upper limits on the dark matter annihilation cross-section. Using gamma-ray ux upper limits from the Fermi satellite and MAGIC, we determine cross-section exclusion regions for dark matter annihilation into a variety of different particles including charged leptons. We show that these exclusion regions are beginning to probe the regions of interest for a dark matter interpretation of the electron and positron uxes from PAMELA, Fermi, and HESS, and that future observations of Segue 1 have strong prospects for testing such an interpretation. We additionally discuss prospects for detecting annihilation with neutrinos using the IceCube detector, finding that in an optimistic scenario a few neutrino events may be detected. Finally we use the kinematic data to model the Segue 1 dark matter velocity dispersion and constrain Sommerfeld enhanced models.

  13. Hubble Space Telescope: Faint object camera instrument handbook. Version 2.0

    NASA Technical Reports Server (NTRS)

    Paresce, Francesco (Editor)

    1990-01-01

    The Faint Object Camera (FOC) is a long focal ratio, photon counting device designed to take high resolution two dimensional images of areas of the sky up to 44 by 44 arcseconds squared in size, with pixel dimensions as small as 0.0007 by 0.0007 arcseconds squared in the 1150 to 6500 A wavelength range. The basic aim of the handbook is to make relevant information about the FOC available to a wide range of astronomers, many of whom may wish to apply for HST observing time. The FOC, as presently configured, is briefly described, and some basic performance parameters are summarized. Also included are detailed performance parameters and instructions on how to derive approximate FOC exposure times for the proposed targets.

  14. Hubble Space Telescope faint object camera instrument handbook (Post-COSTAR), version 5.0

    NASA Technical Reports Server (NTRS)

    Nota, A. (Editor); Jedrzejewski, R. (Editor); Greenfield, P. (Editor); Hack, W. (Editor)

    1994-01-01

    The faint object camera (FOC) is a long-focal-ratio, photon-counting device capable of taking high-resolution two-dimensional images of the sky up to 14 by 14 arc seconds squared in size with pixel dimensions as small as 0.014 by 0.014 arc seconds squared in the 1150 to 6500 A wavelength range. Its performance approaches that of an ideal imaging system at low light levels. The FOC is the only instrument on board the Hubble Space Telescope (HST) to fully use the spatial resolution capabilities of the optical telescope assembly (OTA) and is one of the European Space Agency's contributions to the HST program.

  15. A model atmosphere analysis of the faint early-type halo star PHL 346

    NASA Astrophysics Data System (ADS)

    Keenan, F. P.; Lennon, D. J.; Brown, P. J. F.; Dufton, P. L.

    1986-08-01

    Stellar equivalent widths and hydrogen line profiles, measured from high-resolution optical spectra obtained with the 2.5 m Issac Newton Telescope, are used in conjunction with model atmosphere calculations to determine the atmospheric parameters and chemical composition of the faint, high galactic latitude early-type star PHL 346. The effective temperature (Teff = 22,600 + or - 1000 K) and surface gravity (log g = 3.6 + or - 0.2), as well as the chemical composition, are found to be similar to those of normal OB stars. Therefore, it is concluded that PHL 346 is an ordinary Population I object, at a z distance of 8.7 + or - 1.5 kpc. The relatively small stellar velocity in the z-direction (Vz = +56 + or - 10 km/s) then implies that PHL 346 must have been formed in the halo, possibly from galactic fountain material at a z distance of about 6 kpc.

  16. The ISON international campaigns for monitoring of faint high altitude objects

    NASA Astrophysics Data System (ADS)

    Molotov, Igor; Agapov, Vladimir; Rumyantsev, Vasiliy; Biryukov, Vadim; Schildknecht, Thomas; Bakhtigaraev, Nail; Ibrahimov, Mansur; Papushev, Pavel; Minikulov, Nasredin; Andrievsky, Sergei

    The research of the space debris fragments at high orbits is one of the main directions of the International Scientific Optical Network (ISON) activities. Therefore the dedicated ISON subsystem for high altitude faint space debris observations is arranged with the aim of detection and continuous tracking of as large number of unknown high altitude faint objects as possible. The subsystem includes the number of large telescopes that are able to detect the objects down to 20m-21m and the middle-size telescopes for the observations of the space objects of 15m-18m. The 1-m ZIMLAT in Zimmerwald, Switzerland, 1.5-m AZT-33IK in Mondy, Siberia, 64-cm AT- 64 in Nauchniy, Crimea, 60-cm RK-600 in Mayaki near Odessa, Ukraine, 60-cm Zeiss-600 in Maidanak, Uzbekistan, 70-cm AZT-8 in Gissar, Tajikistan are regularly participating in ISON observing campaigns in collaboration with 1-m Zeiss-1000 ESA space debris telescope in Teide, Canaries islands. 2.6-m ZTSh in Nauchniy, Crimea, 2-m Zeiss-2000 in Terskol, North Caucasus, 1-m Zeiss-1000 in Simeiz, Crimea, 1-m Zeiss-1000 in Arkhyz, North Caucasus are joining during few nights per month. The 60-cm Zeiss-600 in Arkhyz, 70-cm AZT-8 in Evpatoria, Crimea, 60-cm Zeiss-600 in Tarija, Bolivia, 80-cm RK-800 in Mayaki, 80-cm K-800 in Terskol, 50-cm in Ussuriysk, Far East will be added to the subsystem during 2008. The observing campaigns are coordinates by the Center on space debris data collection, processing and analysis of the KIAM RAS in cooperation with the AIUB space debris team. 353 faint objects are discovered in GEO region surveys during the last 3 years (about 100000 measurements were collected for this time), including objects with high AMR. Results are publishing monthly by KIAM in High Geocentric Orbit Space Debris Circular. We will discuss the most interesting of obtained results. Many of discovered fragments are associated with space debris clouds appeared as a result of known or suspected fragmentations occurred in GEO region

  17. The Faint Young Sun Paradox in the Context of Modern Cosmology

    NASA Astrophysics Data System (ADS)

    Dumin, Yu. V.

    2015-09-01

    The Faint Young Sun Paradox comes from the fact that solar luminosity (2-4)x10^9 years ago was insufficient to support the Earth's temperature necessary for the efficient development of geological and biological evolution (particularly, for the existence of considerable volumes of liquid water). It remains unclear by now if the so-called greenhouse effect on the Earth can resolve this problem. An interesting alternative explanation was put forward recently by M.Krizek (New Astron. 2012, 17, 1), who suggested that planetary orbits expand with time due to the local Hubble effect, caused by the uniformly-distributed Dark Energy. Then, under a reasonable value of the local Hubble constant, it is easy to explain why the Earth was receiving an approximately constant amount of solar irradiation for a long period in the past and will continue to do so for a quite long time in future.

  18. VizieR Online Data Catalog: Faint Blue Objects at High Galactic Latitude (Warnock+ 1982)

    NASA Astrophysics Data System (ADS)

    Warnock, A., III; Usher, P. D.

    1995-05-01

    The data set of Faint Blue Objects at High Galactic Latitude is a catalog of objects selected according to relative ultraviolet excess from ubv three-color 1.2-m Palomar Schmidt plates. Five selected area fields centered on SA28, SA29, SA55, SA57 and SA94 are included. The data consist of color classifications, B magnitudes, 1950 equatorial coordinates and remarks; the current file contains 3678 objects. Three selected area fields were included originally, centered on SA57 (Usher 1981), SA29 (Usher, Mattson and Warnock 1982) and SA28 (Usher and Mitchell 1982). Areas centered on SA55 and SA94 were added in 1984. (1 data file).

  19. Genome of the red alga Porphyridium purpureum.

    PubMed

    Bhattacharya, Debashish; Price, Dana C; Chan, Cheong Xin; Qiu, Huan; Rose, Nicholas; Ball, Steven; Weber, Andreas P M; Arias, Maria Cecilia; Henrissat, Bernard; Coutinho, Pedro M; Krishnan, Anagha; Zäuner, Simone; Morath, Shannon; Hilliou, Frédérique; Egizi, Andrea; Perrineau, Marie-Mathilde; Yoon, Hwan Su

    2013-01-01

    The limited knowledge we have about red algal genomes comes from the highly specialized extremophiles, Cyanidiophyceae. Here, we describe the first genome sequence from a mesophilic, unicellular red alga, Porphyridium purpureum. The 8,355 predicted genes in P. purpureum, hundreds of which are likely to be implicated in a history of horizontal gene transfer, reside in a genome of 19.7 Mbp with 235 spliceosomal introns. Analysis of light-harvesting complex proteins reveals a nuclear-encoded phycobiliprotein in the alga. We uncover a complex set of carbohydrate-active enzymes, identify the genes required for the methylerythritol phosphate pathway of isoprenoid biosynthesis, and find evidence of sexual reproduction. Analysis of the compact, function-rich genome of P. purpureum suggests that ancestral lineages of red algae acted as mediators of horizontal gene transfer between prokaryotes and photosynthetic eukaryotes, thereby significantly enriching genomes across the tree of photosynthetic life. PMID:23770768

  20. A Chemical Confirmation of the Faint Boötes II Dwarf Spheroidal Galaxy

    NASA Astrophysics Data System (ADS)

    Koch, Andreas; Rich, R. Michael

    2014-10-01

    We present a chemical abundance study of the brightest confirmed member star of the ultra-faint dwarf galaxy Boötes II from Keck/HIRES high-resolution spectroscopy at moderate signal-to-noise ratios. At [Fe/H] = -2.93 ± 0.03(stat.) ± 0.17(sys.), this star chemically resembles metal-poor halo field stars and the signatures of other faint dwarf spheroidal galaxies at the same metallicities in that it shows enhanced [α/Fe] ratios, Solar Fe-peak element abundances, and low upper limits on the neutron-capture element Ba. Moreover, this star shows no chemical peculiarities in any of the eight elements we were able to measure. This implies that the chemical outliers found in other systems remain outliers pertaining to the unusual enrichment histories of the respective environments, while Boo II appears to have experienced an enrichment history typical of its very low mass. We also re-calibrated previous measurements of the galaxy's metallicity from the calcium triplet (CaT) and find a much lower value than reported before. The resulting broad metallicity spread, in excess of one dex, the very metal-poor mean, and the chemical abundance patterns of the present star imply that Boötes II is a low-mass, old, metal-poor dwarf galaxy and not an overdensity associated with the Sagittarius Stream as has been previously suggested based on its sky position and kinematics. The low, mean CaT metallicity of -2.7 dex falls right on the luminosity-metallicity relation delineated over four orders of magnitude from the more luminous to the faintest galaxies. Thus Boötes II's chemical enrichment appears representative of the galaxy's original mass, while tidal stripping and other mass loss mechanisms were probably not significant as for other low-mass satellites.

  1. The Intensity Distribution of Faint Gamma-Ray Bursts Detected with BATSE

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson M.; Lewin, Walter H. G.; Kouveliotou, Chryssa; VanParadijs, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    2000-01-01

    We have recently completed a search of 6 years of archival BATSE data for gamma-ray bursts (GRBS) that were too faint to activate the real-time burst detection system running on board the spacecraft. These "nontriggered" bursts can be combined with the "triggered" bursts detected on board to produce a GRB intensity distribution that reaches peak fluxes a factor of approximately 2 lower than could be studied previously. The value of the statistic (in Euclidean space) for the bursts we detect is 0.177 plus or minus 0.006. This surprisingly low value is obtained because we detected very few bursts on the 4.096 s and 8.192 s timescales (where most bursts have their highest signal-to-noise ratio) that were not already detected on the 1.024 s timescale. If allowance is made for a power-law distribution of intrinsic peak luminosities, the extended peak flux distribution is consistent with models in which the redshift distribution of the gamma-ray burst rate approximately traces the star formation history of the universe. We argue that this class of models is preferred over those in which the burst rate is independent of redshift. We use the peak flux distribution to derive a limit of 10% (99% confidence) on the fraction of the total burst rate that could be contributed by a spatially homogeneous (in Euclidean space) subpopulation of burst sources, such as type lb/c supernovae. These results lend support to the conclusions of previous studies predicting that relatively few faint "classical" GRBs will be found below the BATSE onboard detection threshold.

  2. FAINT NEAR-ULTRAVIOLET/FAR-ULTRAVIOLET STANDARDS FROM SWIFT/UVOT, GALEX, AND SDSS PHOTOMETRY

    SciTech Connect

    Siegel, Michael H.; Hoversten, Erik A.; Roming, Peter W. A.; Brown, Peter E-mail: hoversten@astro.psu.ed E-mail: brown@astro.psu.ed

    2010-12-10

    At present, the precision of deep ultraviolet photometry is somewhat limited by the dearth of faint ultraviolet standard stars. In an effort to improve this situation, we present a uniform catalog of 11 new faint (u {approx} 17) ultraviolet standard stars. High-precision photometry of these stars has been taken from the Sloan Digital Sky Survey and Galaxy Evolution Explorer archives and combined with new data from the Swift Ultraviolet Optical Telescope to provide precise photometric measures extending from the near-infrared to the far-ultraviolet. These stars were chosen because they are known to be hot (20, 000 < T{sub eff} < 50, 000 K) DA white dwarfs with published Sloan spectra that should be photometrically stable. This careful selection allows us to compare the combined photometry and Sloan spectroscopy to models of pure hydrogen atmospheres to both constrain the underlying properties of the white dwarfs and test the ability of white dwarf models to predict the photometric measures. We find that the photometry provides good constraints on white dwarf temperatures, which demonstrates the ability of Swift/UVOT to investigate the properties of hot luminous stars. We further find that the models reproduce the photometric measures in all 11 passbands to within their systematic uncertainties. Within the limits of our photometry, we find the standard stars to be photometrically stable. This success indicates that the models can be used to calibrate additional filters to our standard system, permitting easier comparison of photometry from heterogeneous sources. The largest source of uncertainty in the model fitting is the uncertainty in the foreground reddening curve, a problem that is especially acute in the UV.

  3. How do we solve the Faint Young Sun Paradox? Examining diverse proposed atmospheres for Early Earth

    NASA Astrophysics Data System (ADS)

    Goldblatt, C.

    2010-12-01

    The canonical problem in Early Earth climatology is the Faint Young Sun Paradox (FYSP): despite receiving much less energy from the Sun than today, the Earth was at least as warm during the Archean Eon as it is today. Clearly, Early Earth had stronger greenhouse effect or lower albedo, yet despite four decades of study, there is no consensus on the solution. The FYSP requires consideration of very different climate regimes to the present day, so provides a great learning tool for diverse and undiscovered climates in Earth's past and future. I will discuss old and new ideas of enhanced greenhouse gas solutions, present a recent proposal that pressure broadening by a thicker nitrogen atmosphere contributed to the solution [1], and a new analysis of what role clouds could have in resolving the FYSP [2]. Various strong greenhouse gas enhancements have been suggested, but all are subject to some problems. A nitrogen inventory greater than the present level was likely in the Archean atmosphere. This would have given a temperature increase of 3 to 8°C by pressure broadening the absorption lines of greenhouse gases. Cloud changes are evaluated relative to the required radiative forcing of +50 Wm-2 to resolve the FYSP. Plausible changes to low clouds (reducing albedo) or high cloud (strengthening the greenhouse effect) could both contribute at most +15Wm-2, so neither fewer low clouds nor more high clouds can provide enough forcing to resolve the FYSP. Decreased surface albedo can contribute no more than +5 Wm-2 forcing. [1] Goldblatt, C. et al., 2009, Nitrogen-enhanced greenhouse warming on early Earth, Nature Geosci., 2, 891 - 896. doi:10.1038/ngeo692 [2] Goldblatt, C. and Zahnle, K. J., 2010, Clouds and the Faint Young Sun Paradox, Clim. Past Discuss., 6, 1337-1350. doi:10.5194/cpd-6-1337-2010

  4. Physical Characteristics of Faint Meteors by Light Curve and High-resolution Observations

    NASA Astrophysics Data System (ADS)

    Subasinghe, Dilini; Campbell-Brown, Margaret D.; Stokan, Edward

    2014-11-01

    The physical structure of a meteoroid may be inferred from optical observations, particularly the light curve, of a meteor. For example: a classically shaped (late peaked) light curve is seen as evidence of a solid single body, whereas a symmetric light curve may indicate a dustball structure. High-resolution optical observations show how the meteoroid fragments: continuously, leaving a long wake, or discretely, leaving several distinct pieces. Calculating the orbit of the meteoroid using two station data then allows the object to be associated with asteroidal or cometary parent bodies. Optical observations thus provide simultaneous information on meteoroid structure, fragmentation mode, and origin.CAMO (the Canadian Automated Meteor Observatory) has been continuously collecting faint (masses < 10-4 kg) two station optical meteors with image-intensified narrow field (with a resolution of up to 3 meters per pixel) and wide field (26 by 19 degrees) cameras since 2010. The narrow field, telescopic cameras allow the meteor fragmentation to be studied using a pair of mirrors to track the meteor. The wide-field cameras provide the light curve and trajectory solution.We present preliminary results from classifying light curves and high-resolution optical observations for 3000 faint meteors recorded since 2010. We find that most meteors (both asteroidal and cometary) show long trails, while meteors with short trails are the second most common morphology. It is expected that meteoroids that experience negligible fragmentation have the shortest trails, so our results imply that the majority of small meteoroids fragment during ablation. A surprising observation is that almost equal fractions of asteroidal and cometary meteors fragment (showing long trails), implying a similar structure for both types of meteoroids.

  5. A chemical confirmation of the faint Boötes II dwarf spheroidal galaxy

    SciTech Connect

    Koch, Andreas; Rich, R. Michael

    2014-10-10

    We present a chemical abundance study of the brightest confirmed member star of the ultra-faint dwarf galaxy Boötes II from Keck/HIRES high-resolution spectroscopy at moderate signal-to-noise ratios. At [Fe/H] = –2.93 ± 0.03(stat.) ± 0.17(sys.), this star chemically resembles metal-poor halo field stars and the signatures of other faint dwarf spheroidal galaxies at the same metallicities in that it shows enhanced [α/Fe] ratios, Solar Fe-peak element abundances, and low upper limits on the neutron-capture element Ba. Moreover, this star shows no chemical peculiarities in any of the eight elements we were able to measure. This implies that the chemical outliers found in other systems remain outliers pertaining to the unusual enrichment histories of the respective environments, while Boo II appears to have experienced an enrichment history typical of its very low mass. We also re-calibrated previous measurements of the galaxy's metallicity from the calcium triplet (CaT) and find a much lower value than reported before. The resulting broad metallicity spread, in excess of one dex, the very metal-poor mean, and the chemical abundance patterns of the present star imply that Boötes II is a low-mass, old, metal-poor dwarf galaxy and not an overdensity associated with the Sagittarius Stream as has been previously suggested based on its sky position and kinematics. The low, mean CaT metallicity of –2.7 dex falls right on the luminosity-metallicity relation delineated over four orders of magnitude from the more luminous to the faintest galaxies. Thus Boötes II's chemical enrichment appears representative of the galaxy's original mass, while tidal stripping and other mass loss mechanisms were probably not significant as for other low-mass satellites.

  6. The faint radio source population at 15.7 GHz - II. Multi-wavelength properties

    NASA Astrophysics Data System (ADS)

    Whittam, I. H.; Riley, J. M.; Green, D. A.; Jarvis, M. J.; Vaccari, M.

    2015-11-01

    A complete, flux density limited sample of 96 faint (>0.5 mJy) radio sources is selected from the 10C survey at 15.7 GHz in the Lockman Hole. We have matched this sample to a range of multi-wavelength catalogues, including Spitzer Extragalactic Representative Volume Survey, Spitzer Wide-area Infrared Extragalactic survey, United Kingdom Infrared Telescope Infrared Deep Sky Survey and optical data; multi-wavelength counterparts are found for 80 of the 96 sources and spectroscopic redshifts are available for 24 sources. Photometric redshifts are estimated for the sources with multi-wavelength data available; the median redshift of the sample is 0.91 with an interquartile range of 0.84. Radio-to-optical ratios show that at least 94 per cent of the sample are radio loud, indicating that the 10C sample is dominated by radio galaxies. This is in contrast to samples selected at lower frequencies, where radio-quiet AGN and star-forming galaxies are present in significant numbers at these flux density levels. All six radio-quiet sources have rising radio spectra, suggesting that they are dominated by AGN emission. These results confirm the conclusions of Paper I that the faint, flat-spectrum sources which are found to dominate the 10C sample below ˜1 mJy are the cores of radio galaxies. The properties of the 10C sample are compared to the Square Kilometre Array Design Studies Simulated Skies; a population of low-redshift star-forming galaxies predicted by the simulation is not found in the observed sample.

  7. Stellar Archeology in the Galactic Halo with Ultra-faint Dwarfs. VII. Hercules

    NASA Astrophysics Data System (ADS)

    Musella, Ilaria; Ripepi, Vincenzo; Marconi, Marcella; Clementini, Gisella; Dall'Ora, Massimo; Scowcroft, Victoria; Moretti, Maria Ida; Di Fabrizio, Luca; Greco, Claudia; Coppola, Giuseppina; Bersier, David; Catelan, Márcio; Grado, Aniello; Limatola, Luca; Smith, Horace A.; Kinemuchi, Karen

    2012-09-01

    We present the first time-series study of the ultra-faint dwarf galaxy Hercules. Using a variety of telescope/instrument facilities we secured about 50 V and 80 B epochs. These data allowed us to detect and characterize 10 pulsating variable stars in Hercules. Our final sample includes six fundamental-mode (ab-type) and three first-overtone (c-type) RR Lyrae stars, and one Anomalous Cepheid. The average period of the ab-type RR Lyrae stars, langP abrang = 0.68 days (σ = 0.03 days), places Hercules in the Oosterhoff II group, as found for almost the totality of the ultra-faint dwarf galaxies investigated so far for variability. The RR Lyrae stars were used to obtain independent estimates of the metallicity, reddening, and distance to Hercules, for which we find [Fe/H] = -2.30 ± 0.15 dex, E(B - V) = 0.09 ± 0.02 mag, and (m - M)0 = 20.6 ± 0.1 mag, in good agreement with the literature values. We have obtained a V, B - V color-magnitude diagram (CMD) of Hercules that reaches V ~ 25 mag and extends beyond the galaxy's half-light radius over a total area of 40' × 36'. The CMD and the RR Lyrae stars indicate the presence of a population as old and metal-poor as (at least) the Galactic globular cluster M68. Based on data collected at the 2.5 m Isaac Newton Telescope, La Palma, Canary Islands, Spain, at the 4.2 m William Herschel Telescope, Roche de los Muchachos, Canary Islands, Spain, at the 2.2 m ESO/MPI telescope, La Silla, Chile, Proposal 079.D-0587, at the 2 m Liverpool Telescope, Roche de los Muchachos, Canary Islands, Spain, and at the 2 m Faulkes Telescope North, Haleakala Observatory, Hawaii, USA.

  8. First results from the faint object camera - High-resolution imaging of the Pluto-Charon system

    NASA Technical Reports Server (NTRS)

    Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.; Crane, P.

    1991-01-01

    The first observations of a solar system target with the Faint Object Camera of the HST are reported. Observations of the Pluto-Charon system were obtained in f/96 and f/288 mode. Pluto and Charon were clearly resolved, and the observed separation and diameters are in accordance with expectations. The f/96 data were astrometrically and photometrically analyzed; preliminary results are presented.

  9. THE STELLAR INITIAL MASS FUNCTION OF ULTRA-FAINT DWARF GALAXIES: EVIDENCE FOR IMF VARIATIONS WITH GALACTIC ENVIRONMENT

    SciTech Connect

    Geha, Marla; Brown, Thomas M.; Tumlinson, Jason; Kalirai, Jason S.; Avila, Roberto J.; Ferguson, Henry C.; Simon, Joshua D.; Kirby, Evan N.; VandenBerg, Don A.; Munoz, Ricardo R.; Guhathakurta, Puragra E-mail: tbrown@stsci.edu

    2013-07-01

    We present constraints on the stellar initial mass function (IMF) in two ultra-faint dwarf (UFD) galaxies, Hercules and Leo IV, based on deep Hubble Space Telescope Advanced Camera for Surveys imaging. The Hercules and Leo IV galaxies are extremely low luminosity (M{sub V} = -6.2, -5.5), metal-poor (([Fe/H]) = -2.4, -2.5) systems that have old stellar populations (>11 Gyr). Because they have long relaxation times, we can directly measure the low-mass stellar IMF by counting stars below the main-sequence turnoff without correcting for dynamical evolution. Over the stellar mass range probed by our data, 0.52-0.77 M{sub Sun }, the IMF is best fit by a power-law slope of {alpha}= 1.2{sub -0.5}{sup +0.4} for Hercules and {alpha} = 1.3 {+-} 0.8 for Leo IV. For Hercules, the IMF slope is more shallow than a Salpeter ({alpha} = 2.35) IMF at the 5.8{sigma} level, and a Kroupa ({alpha} = 2.3 above 0.5 M{sub Sun }) IMF slope at 5.4{sigma} level. We simultaneously fit for the binary fraction, f{sub binary}, finding f{sub binary}= 0.47{sup +0.16}{sub -0.14} for Hercules, and 0.47{sup +0.37}{sub -0.17} for Leo IV. The UFD binary fractions are consistent with that inferred for Milky Way stars in the same mass range, despite very different metallicities. In contrast, the IMF slopes in the UFDs are shallower than other galactic environments. In the mass range 0.5-0.8 M{sub Sun }, we see a trend across the handful of galaxies with directly measured IMFs such that the power-law slopes become shallower (more bottom-light) with decreasing galactic velocity dispersion and metallicity. This trend is qualitatively consistent with results in elliptical galaxies inferred via indirect methods and is direct evidence for IMF variations with galactic environment.

  10. Revealing the Nature of Faint X-Ray Sources in the Giant Star-Forming Region NGC 3603

    NASA Astrophysics Data System (ADS)

    Poteet, C.; Marchenko, S.; Corcoran, M.; Andersen, M.

    2004-12-01

    NGC 3603, an open cluster embedded in the largest Galactic H II region, contains some of the most luminous, massive stars known in the Galaxy. It may serve as a good analog of star-forming regions in external starburst galaxies. The recent deep (50 Ksec) {Chandra} imaging of NGC 3603 revealed that its X-Ray emission is dominated by the bright Wolf-Rayet and O stars in the cluster core. However, there are hundreds of extremely weak point-like X-ray sources surrounding the central region. They tend to concentrate towards the cluster's center, suggestive of real cluster membership. Studying this population, we find that absolute majority of the weak sources does not belong to the lists of known OB and WR cluster members. Practically all the 263 weak X-ray sources have faint near-IR counterparts in the deep J,H,K images obtained by the ISAAC instrument on the VLT. Around 50% of the X-ray sources can be considered as visual binaries, an additional ˜ 20% as multiple systems (up to six stars in a r=1.5" ˜ 3σ circle). The composite spectrum of these sources is quite hard (kT ˜ 6 keV) and fairly absorbed (NH ˜ 1022). There is no obvious line emission, in particular, no strong Fe XXV line, so presently we cannot distinguish between thermal and non-thermal emission. The JHK colour-colour and colour-magnitude diagrams of the X-ray selected sources indicate that the X-ray data are very efficient in discriminating between field stars and cluster members. The X-ray sources have similar near-infrared properties as the whole near-infrared sample of the known cluster members. Hence, the discovered population of weak X-ray sources provide an effective means to obtain a "clean" sample of pre-main sequence stars down to 1 M⊙ assuming the cluster is 1 Myr old.

  11. A comparative analysis of the observed white dwarf cooling sequence from globular clusters★

    NASA Astrophysics Data System (ADS)

    Campos, Fabíola; Bergeron, P.; Romero, A. D.; Kepler, S. O.; Ourique, G.; Costa, J. E. S.; Bonatto, C. J.; Winget, D. E.; Montgomery, M. H.; Pacheco, T. A.; Bedin, L. R.

    2016-03-01

    We report our study of features at the observed red end of the white dwarf cooling sequences for three Galactic globular clusters: NGC 6397, 47 Tucanae and M 4. We use deep colour-magnitude diagrams constructed from archival Hubble Space Telescope (Advanced Camera for Surveys) to systematically investigate the blue turn at faint magnitudes and the age determinations for each cluster. We find that the age difference between NGC 6397 and 47 Tuc is 1.98^{+0.44}_{-0.26} Gyr, consistent with the picture that metal-rich halo clusters were formed later than metal-poor halo clusters. We self-consistently include the effect of metallicity on the progenitor age and the initial-to-final mass relation. In contrast with previous investigations that invoked a single white dwarf mass for each cluster, the data show a spread of white dwarf masses that better reproduce the shape and location of the blue turn. This effect alone, however, does not completely reproduce the observational data - the blue turn retains some mystery. In this context, we discuss several other potential problems in the models. These include possible partial mixing of H and He in the atmosphere of white dwarf stars, the lack of a good physical description of the collision-induced absorption process and uncertainties in the opacities at low temperatures. The latter are already known to be significant in the description of the cool main sequence. Additionally, we find that the present-day local mass function of NGC 6397 is consistent with a top-heavy type, while 47 Tuc presents a bottom-heavy profile.

  12. A multiwavelength consensus on the main sequence of star-forming galaxies at z ˜ 2

    NASA Astrophysics Data System (ADS)

    Rodighiero, G.; Renzini, A.; Daddi, E.; Baronchelli, I.; Berta, S.; Cresci, G.; Franceschini, A.; Gruppioni, C.; Lutz, D.; Mancini, C.; Santini, P.; Zamorani, G.; Silverman, J.; Kashino, D.; Andreani, P.; Cimatti, A.; Sánchez, H. Domínguez; Le Floch, E.; Magnelli, B.; Popesso, P.; Pozzi, F.

    2014-09-01

    We compare various star formation rate (SFR) indicators for star-forming galaxies at 1.4 < z < 2.5 in the COSMOS field. The main focus is on the SFRs from the far-IR (PACS-Herschel data) with those from the ultraviolet, for galaxies selected according to the BzK criterion. FIR-selected samples lead to a vastly different slope of the SFR-stellar mass (M*) relation, compared to that of the dominant main-sequence population as measured from the UV, since the FIR selection picks predominantly only a minority of outliers. However, there is overall agreement between the main sequences derived with the two SFR indicators, when stacking on the PACS maps the BzK-selected galaxies. The resulting logarithmic slope of the SFR-M* relation is ˜0.8-0.9, in agreement with that derived from the dust-corrected UV luminosity. Exploiting deeper 24 μm Spitzer data, we have characterized a subsample of galaxies with reddening and SFRs poorly constrained, as they are very faint in the B band. The combination of Herschel with Spitzer data has allowed us to largely break the age/reddening degeneracy for these intriguing sources, by distinguishing whether a galaxy is very red in B-z because of being heavily dust reddened, or whether because star formation has been (or is being) quenched. Finally, we have compared our SFR(UV) to the SFRs derived by stacking the radio data and to those derived from the Hα luminosity of a sample of star-forming galaxies at 1.4 < z < 1.7. The two sets of SFRs are broadly consistent as they are with the SFRs derived from the UV and by stacking the corresponding PACS data in various mass bins.

  13. Red Bull Stratos Presentation

    NASA Video Gallery

    Red Bull Stratos High Performance Director Andy Walshe & Technical Project Director Art Thompson share the Stratos story with JSC. Supported by a team of experts, Felix Baumgartner reached 128,100 ...

  14. Jupiter's Great Red Spot

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This view of Jupiter's Great Red Spot is a mosaic of two images taken by the Galileo spacecraft. The image was created using two filters, violet and near-infrared, at each of two camera positions. The Great Red Spot is a storm in Jupiter's atmosphere and is at least 300 years-old. Winds blow counterclockwise around the Great Red Spot at about 400 kilometers per hour (250 miles per hour). The size of the storm is more than one Earth diameter (13,000 kilometers or 8,000 miles) in the north-south direction and more than two Earth diameters in the east-west direction. In this oblique view, where the Great Red Spot is shown on the planet's limb, it appears longer in the north-south direction. The image was taken on June 26, 1996.

    The Galileo mission is managed by NASA's Jet Propulsion Laboratory.

  15. Red blood cell production

    MedlinePlus Videos and Cool Tools

    ... or another. Red blood cells are an important element of blood. Their job is to transport oxygen ... hemocytoblasts give rise to all of the formed elements in blood. If a hemocytoblast commits to becoming ...

  16. Voyager 1 Red Spot Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This movie shows the portion of Jupiter around the Great Red Spot as it swirls through more than 60 Jupiter days. Notice the difference in speed and direction of the various zones of the atmosphere. The interaction of the atmospheric clouds and storm shows how dynamic the Jovian atmosphere is.

    As Voyager 1 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 66 images taken once every Jupiter rotation period (about 10 hours). This time-lapse movie uses images taken every time Jupiter longitude 68W passed under the spacecraft. These images were acquired in the Blue filter from Jan. 6 to Feb. 3 1979. The spacecraft flew from 58 million kilometers to 31 million kilometers from Jupiter during that time.

    This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

  17. The significance of faint visualization of the superior sagittal sinus in brain scintigraphy for the diagnosis of brain death

    SciTech Connect

    Bisset, R.; Sfakianakis, G.; Ihmedian, I.; Holzman, B.; Curless, R.; Serafini, A.

    1985-05-01

    Brain death is associated with cessation of blood flow to the brain. Tc-99m brain flow studies are used as a laboratory confirmatory test for the establishment of the diagnosis of brain death. Criteria for the diagnosis of cessation of blood flow to the brain are 1) visualization of carotid artery activity in the neck of the patient and 2) no visualization of activity in the distribution of the anterior and middle cerebral arteries. The authors noticed that in a significant number of patients, although there was no visualization of arterial blood flow to the brain the static images demonstrated faint accumulation of activity in the region of the superior sagittal sinus (SSS). In a four year period 212 brain flow studies were performed in 154 patients for diagnosis of brain death; of them 137 studies (65%) showed no evidence of arterial flow. In 103 out of the 137 studies (75%) there was no visualization of the SSS; in the remaining 34 studies (3l patients) however three patterns of faint activity attributed to partial and or faint visualization of the SSS could be recognized at the midline of the immediate anterior static view: a) linear from the cranial vault floor up b) disk shaped at the apex of the vault and c) disk shaped at the apex tailing caudad. All of the 3l patients in this group satisfied brain death criteria within four days of the last study which showed faint visualization of the superior sagittal sinus. The authors conclude that even in the presence of a faint visualization of the superior sagittal sinus on static post brain flow scintigraphy, the diagnosis of cessation of blood flow to the brain can be made if there is no evidence of arterial blood flow.

  18. THE VERY FAINT END OF THE UV LUMINOSITY FUNCTION OVER COSMIC TIME: CONSTRAINTS FROM THE LOCAL GROUP FOSSIL RECORD

    SciTech Connect

    Weisz, Daniel R.; Johnson, Benjamin D.; Conroy, Charlie

    2014-10-10

    We present a new technique to estimate the evolution of the very faint end of the UV luminosity function (LF) out to z ∼ 5. Measured star formation histories (SFHs) from the fossil record of Local Group (LG) galaxies are used to reconstruct the LF down to M {sub UV} ∼–5 at z ∼ 5 and M {sub UV} ∼–1.5 at z < 1. Such faint limits are well beyond the current observational limits and are likely to remain beyond the limits of next-generation facilities. The reconstructed LFs, when combined with direct measurements of the LFs at higher luminosity, are well-fit by a standard Schechter function with no evidence of a break to the faintest limits probed by this technique. The derived faint-end slope, α, steepens from ≈ – 1.2 at z < 1 to ≈ – 1.6 at 4 < z < 5. We test the effects of burstiness in the SFHs and find the recovered LFs to be only modestly affected. Incompleteness corrections for the faintest LG galaxies and the (unlikely) possibility of significant luminosity-dependent destruction of dwarf galaxies between high redshift and the present epoch are important uncertainties. These and other uncertainties can be mitigated with more detailed modeling and future observations. The reconstructed faint end LF from the fossil record can therefore be a powerful and complementary probe of the high-redshift faint galaxies believed to play a key role in the reionization of the universe.

  19. Tests of two convection theories for red giant and red supergiant envelopes

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.; Chin, Chao-Wen

    1995-01-01

    Two theories of stellar envelope convection are considered here in the context of red giants and red supergiants of intermediate to high mass: Boehm-Vitense's standard mixing-length theory (MLT) and Canuto & Mazzitelli's new theory incorporating the full spectrum of turbulence (FST). Both theories assume incompressible convection. Two formulations of the convective mixing length are also evaluated: l proportional to the local pressure scale height (H(sub P)) and l proportional to the distance from the upper boundary of the convection zone (z). Applications to test both theories are made by calculating stellar evolutionary sequences into the red zone (z). Applications to test both theories are made by calculating stellar evolutionary sequences into the red phase of core helium burning. Since the theoretically predicted effective temperatures for cool stars are known to be sensitive to the assigned value of the mixing length, this quantity has been individually calibrated for each evolutionary sequence. The calibration is done in a composite Hertzsprung-Russell diagram for the red giant and red supergiant members of well-observed Galactic open clusters. The MLT model requires the constant of proportionality for the convective mixing length to vary by a small but statistically significant amount with stellar mass, whereas the FST model succeeds in all cases with the mixing lenghth simply set equal to z. The structure of the deep stellar interior, however, remains very nearly unaffected by the choices of convection theory and mixing lenghth. Inside the convective envelope itself, a density inversion always occurs, but is somewhat smaller for the convectively more efficient MLT model. On physical grounds the FST model is preferable, and seems to alleviate the problem of finding the proper mixing length.

  20. Faint Coronal Hard X-rays From Accelerated Electrons in Solar Flares

    NASA Astrophysics Data System (ADS)

    Glesener, Lindsay Erin

    Solar flares are huge explosions on the Sun that release a tremendous amount of energy from the coronal magnetic field, up to 1033 ergs, in a short time (100--1000 seconds), with much of the energy going into accelerated electrons and ions. An efficient acceleration mechanism is needed, but the details of this mechanism remain relatively unknown. A fraction of this explosive energy reaches the Earth in the form of energetic particles, producing geomagnetic storms and posing dangers to spaceborne instruments, astronauts, and Earthbound power grids. There are thus practical reasons, as well as intellectual ones, for wishing to understand this extraordinary form of energy release. Through imaging spectroscopy of the hard X-ray (HXR) emission from solar flares, the behavior of flare-accelerated electrons can be studied. The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI ) spacecraft launched in 2002 with the goal of better understanding flare particle acceleration. Using rotation modulation collimators, RHESSI is able to cover a wide energy range (3 keV--17 MeV) with fine angular and energy resolutions. RHESSI's success in the last 10 years in investigating the relationship between energetic electrons and ions, the nature of faint sources in the corona, the energy distribution of flares, and several other topics have significantly advanced the understanding of flares. But along with the wealth of information revealed by RHESSI come some clear observational challenges. Very few, if any, RHESSI observations have come close to imaging the electron acceleration region itself. This is undoubtedly due to a lack of both sensitivity (HXRs from electron beams in the tenuous corona are faint) and dynamic range (HXR sources at chromospheric flare footpoints are much brighter and tend to obscure faint coronal sources). Greater sensitivity is also required to investigate the role that small flares in the quiet Sun could play in heating the corona. The Focusing Optics

  1. Statistical Track-Before-Detect Methods Applied to Faint Optical Observations of Resident Space Objects

    NASA Astrophysics Data System (ADS)

    Fujimoto, K.; Yanagisawa, T.; Uetsuhara, M.

    Automated detection and tracking of faint objects in optical, or bearing-only, sensor imagery is a topic of immense interest in space surveillance. Robust methods in this realm will lead to better space situational awareness (SSA) while reducing the cost of sensors and optics. They are especially relevant in the search for high area-to-mass ratio (HAMR) objects, as their apparent brightness can change significantly over time. A track-before-detect (TBD) approach has been shown to be suitable for faint, low signal-to-noise ratio (SNR) images of resident space objects (RSOs). TBD does not rely upon the extraction of feature points within the image based on some thresholding criteria, but rather directly takes as input the intensity information from the image file. Not only is all of the available information from the image used, TBD avoids the computational intractability of the conventional feature-based line detection (i.e., "string of pearls") approach to track detection for low SNR data. Implementation of TBD rooted in finite set statistics (FISST) theory has been proposed recently by Vo, et al. Compared to other TBD methods applied so far to SSA, such as the stacking method or multi-pass multi-period denoising, the FISST approach is statistically rigorous and has been shown to be more computationally efficient, thus paving the path toward on-line processing. In this paper, we intend to apply a multi-Bernoulli filter to actual CCD imagery of RSOs. The multi-Bernoulli filter can explicitly account for the birth and death of multiple targets in a measurement arc. TBD is achieved via a sequential Monte Carlo implementation. Preliminary results with simulated single-target data indicate that a Bernoulli filter can successfully track and detect objects with measurement SNR as low as 2.4. Although the advent of fast-cadence scientific CMOS sensors have made the automation of faint object detection a realistic goal, it is nonetheless a difficult goal, as measurements

  2. Star formation rate and extinction in faint z ∼ 4 Lyman break galaxies

    SciTech Connect

    To, Chun-Hao; Wang, Wei-Hao; Owen, Frazer N.

    2014-09-10

    We present a statistical detection of 1.5 GHz radio continuum emission from a sample of faint z ∼ 4 Lyman break galaxies (LBGs). To constrain their extinction and intrinsic star formation rate (SFR), we combine the latest ultradeep Very Large Array 1.5 GHz radio image and the Hubble Space Telescope Advanced Camera for Surveys (ACS) optical images in the GOODS-N. We select a large sample of 1771 z ∼ 4 LBGs from the ACS catalog using B {sub F435W}-dropout color criteria. Our LBG samples have I {sub F775W} ∼ 25-28 (AB), ∼0-3 mag fainter than M{sub UV}{sup ⋆} at z ∼ 4. In our stacked radio images, we find the LBGs to be point-like under our 2'' angular resolution. We measure their mean 1.5 GHz flux by stacking the measurements on the individual objects. We achieve a statistical detection of S {sub 1.5} {sub GHz} = 0.210 ± 0.075 μJy at ∼3σ for the first time on such a faint LBG population at z ∼ 4. The measurement takes into account the effects of source size and blending of multiple objects. The detection is visually confirmed by stacking the radio images of the LBGs, and the uncertainty is quantified with Monte Carlo simulations on the radio image. The stacked radio flux corresponds to an obscured SFR of 16.0 ± 5.7 M {sub ☉} yr{sup –1}, and implies a rest-frame UV extinction correction factor of 3.8. This extinction correction is in excellent agreement with that derived from the observed UV continuum spectral slope, using the local calibration of Meurer et al. This result supports the use of the local calibration on high-redshift LBGs to derive the extinction correction and SFR, and also disfavors a steep reddening curve such as that of the Small Magellanic Cloud.

  3. A bag of tricks: Using proper motions of Galactic stars to identify the Hercules ultra-faint dwarf galaxy members

    NASA Astrophysics Data System (ADS)

    Fabrizio, M.; Raimondo, G.; Brocato, E.; Bellini, A.; Libralato, M.; Testa, V.; Cantiello, M.; Musella, I.; Clementini, G.; Carini, R.; Marconi, M.; Piotto, G.; Ripepi, V.; Buonanno, R.; Sani, E.; Speziali, R.

    2014-10-01

    Context. Discovered in the last decade as overdensities of resolved stars, the ultra-faint dwarfs (UFDs) are among the least luminous, most dark-matter dominated, and most metal-poor galaxies known today. They appear as sparse, loose objects with high mass-to-light ratios. Hercules is the prototype of the UFD galaxies. To date, there are still no firm constraints on its total luminosity due to the difficulty of disentangling Hercules bona-fide stars from the severe Galactic field contamination. Aims: To better constrain Hercules properties, we aim at removing foreground and background contaminants in the galaxy field using the proper motions of the Milky Way stars and the colour-colour diagram. Methods: We have obtained images of Hercules in the rSloan , BBessel and Uspec bands with the Large Binocular Telescope (LBT) and LBC-BIN mode capabilities. The rSloan new dataset combined with data from the LBT archive span a time baseline of about 5 yr, allowing us to measure proper motions of stars in the Hercules direction for the first time. The Uspec data along with existing LBT photometry allowed us to use colour-colour diagram to further remove the field contamination. Results: Thanks to a highly-accurate procedure to derive the rSloan -filter geometric distortion solution for the LBC-red, we were able to measure stellar relative proper motions to a precision of better than 5 mas yr-1 down to rSloan≃ 22 mag and disentangle a significant fraction (>90%) of Milky Way contaminants. We ended up with a sample of 528 sources distributed over a large portion of the galaxy body (~0.12 deg2). Of these sources, 171 turned out to be background galaxies and additional foreground stars from the analysis of the Uspec - BBessel vs. BBessel - rSloan colour-colour diagram. This leaves us with a sample of 357 likely members of the Hercules UFD. We compared the cleaned colour-magnitude diagram (CMD) with evolutionary models and synthetic CMDs, confirming the presence in Hercules of

  4. Repetitive Sequences

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Repetitive sequences, or repeats, account for a substantial portion of the eukaryotic genomes. These sequences include very different types of DNA with respect to mode of origin, function, structure, and genomic distribution. Two large families of repetitive sequences can be readily recognized, ta...

  5. FAINT END OF 1.3 mm NUMBER COUNTS REVEALED BY ALMA

    SciTech Connect

    Hatsukade, Bunyo; Ohta, Kouji; Seko, Akifumi; Yabe, Kiyoto; Akiyama, Masayuki

    2013-06-01

    We present the faint end of number counts at 1.3 mm (238 GHz) obtained with the Atacama Large Millimeter/submillimeter Array (ALMA). Band 6 observations were carried out targeting 20 star-forming galaxies at z ∼ 1.4 in the Subaru/XMM-Newton Deep Survey field. In the observations, we serendipitously detect 15 sources (≥3.8σ, S{sub 1.3} {sub mm} = 0.15-0.61 mJy) other than the targeted sources. We create number counts by using these ''sub-mJy sources'', which probe the faintest flux range among surveys at millimeter wavelengths. The number counts are consistent with (flux-scaled) number counts at 850 μm and 870 μm obtained with gravitational lensing clusters. The ALMA number counts agree well with model predictions, which suggest that these sub-mJy populations are more like ''normal'' star-forming galaxies than ''classical'' submillimeter galaxies with intense star-forming activity. In this flux range, ∼80% of the extragalactic background light at 1.3 mm is resolved into individual sources.

  6. Source Catalog Data from FIRST (Faint Images of the Radio Sky at Twenty-Centimeters)

    DOE Data Explorer

    Becker, Robert H.; Helfand, David J.; White, Richard L.; Gregg, Michael D.; Laurent-Muehleisen, Sally A.

    FIRST, Faint Images of the Radio Sky at Twenty-Centimeters, is a project designed to produce the radio equivalent of the Palomar Observatory Sky Survey over 10,000 square degrees of the North Galactic Cap. Using the National Radio Astronomy Observatory's (NRAO) Very Large Array (VLA) in its B-configuration, the Survey acquired 3-minute snapshots covering a hexagonal grid using 2?7 3-MHz frequency channels centered at 1365 and 1435 MHz. The data were edited, self-calibrated, mapped, and CLEANed using an automated pipeline based largely on routines in the Astronomical Image Processing System (AIPS). A final atlas of maps is produced by coadding the twelve images adjacent to each pointing center. Source catalogs with flux densities and size information are generated from the coadded images also. The 2011 catalog is the latest version and has been tested to ensure reliability and completness. The catalog, generated from the 1993 through 2004 images, contains 816,000 sources and covers more than 9000 square degrees. A specialized search interface for the catalog resides at this website, and the catalog is also available as a compressed ASCII file. The user may also view earlier versions of the source catalog. The FIRST survey area was chosen to coincide with that of the Sloan Digital Sky Survey (SDSS); at the m(v)~24 limit of SDSS, ~50% of the optical counterparts to FIRST sources will be detected.

  7. First faint dual-field off-axis observations in optical long baseline interferometry

    SciTech Connect

    Woillez, J.; Wizinowich, P.; Ragland, S.; Akeson, R.; Millan-Gabet, R.; Colavita, M.; Eisner, J.; Monnier, J. D.; Pott, J.-U.

    2014-03-10

    Ground-based long baseline interferometers have long been limited in sensitivity in part by the short integration periods imposed by atmospheric turbulence. The first observation fainter than this limit was performed on 2011 January 22 when the Keck Interferometer observed a K = 11.5 target, about 1 mag fainter than its K = 10.3 atmospherically imposed limit; the currently demonstrated limit is K = 12.5. These observations were made possible by the Dual-Field Phase-Referencing (DFPR) instrument, part of the NSF-funded ASTrometry and phase-Referenced Astronomy project; integration times longer than the turbulence time scale are made possible by its ability to simultaneously measure the real-time effects of the atmosphere on a nearby bright guide star and correct for it on the faint target. We present the implementation of DFPR on the Keck Interferometer. Then, we detail its on-sky performance focusing on the accuracy of the turbulence correction and the resulting fringe contrast stability.

  8. ACCURATE STELLAR KINEMATICS AT FAINT MAGNITUDES: APPLICATION TO THE BOOeTES I DWARF SPHEROIDAL GALAXY

    SciTech Connect

    Koposov, Sergey E.; Gilmore, G.; Walker, M. G.; Belokurov, V.; Evans, N. Wyn; Okamoto, S.; Penarrubia, J.; Fellhauer, M.; Gieren, W.; Geisler, D.; Monaco, L.; Norris, J. E.; Wilkinson, M.; Wyse, R. F. G.; Zucker, D. B.

    2011-08-01

    We develop, implement, and characterize an enhanced data reduction approach which delivers precise, accurate, radial velocities from moderate resolution spectroscopy with the fiber-fed VLT/FLAMES+GIRAFFE facility. This facility, with appropriate care, delivers radial velocities adequate to resolve the intrinsic velocity dispersions of the very faint dwarf spheroidal (dSph) galaxies. Importantly, repeated measurements let us reliably calibrate our individual velocity errors (0.2 kms{sup -1} {<=} {delta}{sub V} {<=} 5 km s{sup -1}) and directly detect stars with variable radial velocities. We show, by application to the Booetes I dSph, that the intrinsic velocity dispersion of this system is significantly below 6.5 km s{sup -1} reported by previous studies. Our data favor a two-population model of Booetes I, consisting of a majority 'cold' stellar component, with velocity dispersion 2.4{sup +0.9}{sub -0.5} km s{sup -1}, and a minority 'hot' stellar component, with velocity dispersion {approx}9 km s{sup -1}, although we cannot completely rule out a single component distribution with velocity dispersion 4.6{sup 0.8}{sub -0.6} km s{sup -1}. We speculate that this complex velocity distribution actually reflects the distribution of velocity anisotropy in Booetes I, which is a measure of its formation processes.

  9. A faint type of supernova from a white dwarf with a helium-rich companion.

    PubMed

    Perets, H B; Gal-Yam, A; Mazzali, P A; Arnett, D; Kagan, D; Filippenko, A V; Li, W; Arcavi, I; Cenko, S B; Fox, D B; Leonard, D C; Moon, D-S; Sand, D J; Soderberg, A M; Anderson, J P; James, P A; Foley, R J; Ganeshalingam, M; Ofek, E O; Bildsten, L; Nelemans, G; Shen, K J; Weinberg, N N; Metzger, B D; Piro, A L; Quataert, E; Kiewe, M; Poznanski, D

    2010-05-20

    Supernovae are thought to arise from two different physical processes. The cores of massive, short-lived stars undergo gravitational core collapse and typically eject a few solar masses during their explosion. These are thought to appear as type Ib/c and type II supernovae, and are associated with young stellar populations. In contrast, the thermonuclear detonation of a carbon-oxygen white dwarf, whose mass approaches the Chandrasekhar limit, is thought to produce type Ia supernovae. Such supernovae are observed in both young and old stellar environments. Here we report a faint type Ib supernova, SN 2005E, in the halo of the nearby isolated galaxy, NGC 1032. The 'old' environment near the supernova location, and the very low derived ejected mass ( approximately 0.3 solar masses), argue strongly against a core-collapse origin. Spectroscopic observations and analysis reveal high ejecta velocities, dominated by helium-burning products, probably excluding this as a subluminous or a regular type Ia supernova. We conclude that it arises from a low-mass, old progenitor, likely to have been a helium-accreting white dwarf in a binary. The ejecta contain more calcium than observed in other types of supernovae and probably large amounts of radioactive (44)Ti. PMID:20485429

  10. The Quenching of the Ultra-faint Dwarf Galaxies in the Reionization Era

    NASA Astrophysics Data System (ADS)

    Brown, Thomas M.; Tumlinson, Jason; Geha, Marla; Simon, Joshua D.; Vargas, Luis C.; VandenBerg, Don A.; Kirby, Evan N.; Kalirai, Jason S.; Avila, Roberto J.; Gennaro, Mario; Ferguson, Henry C.; Muñoz, Ricardo R.; Guhathakurta, Puragra; Renzini, Alvio

    2014-12-01

    We present new constraints on the star formation histories of six ultra-faint dwarf galaxies: Bootes I, Canes Venatici II, Coma Berenices, Hercules, Leo IV, and Ursa Major I. Our analysis employs a combination of high-precision photometry obtained with the Advanced Camera for Surveys on the Hubble Space Telescope, medium-resolution spectroscopy obtained with the DEep Imaging Multi-Object Spectrograph on the W. M. Keck Observatory, and updated Victoria-Regina isochrones tailored to the abundance patterns appropriate for these galaxies. The data for five of these Milky Way satellites are best fit by a star formation history where at least 75% of the stars formed by z ~ 10 (13.3 Gyr ago). All of the galaxies are consistent with 80% of the stars forming by z ~ 6 (12.8 Gyr ago) and 100% of the stars forming by z ~ 3 (11.6 Gyr ago). The similarly ancient populations of these galaxies support the hypothesis that star formation in the smallest dark-matter sub-halos was suppressed by a global outside influence, such as the reionization of the universe. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program GO-12549.

  11. The faint young Sun paradox: an observational test of an alternative solar model.

    PubMed

    Gaidos, E J; Gudel, M; Blake, G A

    2000-02-15

    We report the results of deep observations at radio (3.6 cm) wavelengths of the nearby solar-type star pi 01 Ursa Majoris with the Very Large Array (VLA) intended to test an alternative theory of solar luminosity evolution. The standard model predicts a solar luminosity only 75% of the present value and surface temperatures below freezing on Earth and Mars at 4 Ga, seemingly in conflict with geologic evidence for liquid water on these planets. An alternative model invokes a compensatory mass loss through a declining solar wind that results in a more consistent early luminosity. The free-free emission from an enhanced wind around nearby young Sun-like stars should be detectable at microwave frequencies. Our observations of pi 01 UMa, a 300 million year-old solar-mass star, place an upper limit on the mass loss rate of 4-5 x 10(-11) M(solar) yr-1. Total mass loss from such a star over 4 Gyr would be less than 6%. If this star is indeed an analog of the early Sun, it casts doubt on the alternative model as a solution to the faint young Sun paradox, particularly for Mars. PMID:11543273

  12. Degree of polarization and source counts of faint radio sources from Stacking Polarized intensity

    SciTech Connect

    Stil, J. M.; George, S. J.; Keller, B. W.; Taylor, A. R.

    2014-06-01

    We present stacking polarized intensity as a means to study the polarization of sources that are too faint to be detected individually in surveys of polarized radio sources. Stacking offers not only high sensitivity to the median signal of a class of radio sources, but also avoids a detection threshold in polarized intensity, and therefore an arbitrary exclusion of sources with a low percentage of polarization. Correction for polarization bias is done through a Monte Carlo analysis and tested on a simulated survey. We show that the nonlinear relation between the real polarized signal and the detected signal requires knowledge of the shape of the distribution of fractional polarization, which we constrain using the ratio of the upper quartile to the lower quartile of the distribution of stacked polarized intensities. Stacking polarized intensity for NRAO VLA Sky Survey (NVSS) sources down to the detection limit in Stokes I, we find a gradual increase in median fractional polarization that is consistent with a trend that was noticed before for bright NVSS sources, but is much more gradual than found by previous deep surveys of radio polarization. Consequently, the polarized radio source counts derived from our stacking experiment predict fewer polarized radio sources for future surveys with the Square Kilometre Array and its pathfinders.

  13. On the Automated and Objective Detection of Emission Lines in Faint-Object Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hong, Sungryong; Dey, Arjun; Prescott, Moire K. M.

    2014-11-01

    Modern spectroscopic surveys produce large spectroscopic databases, generally with sizes well beyond the scope of manual investigation. The need arises, therefore, for an automated line detection method with objective indicators for detection significance. In this paper, we present an automated and objective method for emission line detection in spectroscopic surveys and apply this technique to observed spectra from a Lyα emitter survey at z ~ 2.7, obtained with the Hectospec spectrograph on the MMT Observatory (MMTO). The basic idea is to generate on-source (signal plus noise) and off-source (noise only) mock observations using Monte Carlo simulations, and calculate completeness and reliability values, (C,R), for each simulated signal. By comparing the detections from real data with the Monte Carlo results, we assign the completeness and reliability values to each real detection. From 1574 spectra, we obtain 881 raw detections and, by removing low reliability detections, we finalize 652 detections from an automated pipeline. Most of high completeness and reliability detections, (C,R) ≈ (1.0,1.0), are robust detections when visually inspected; the low C and R detections are also marginal on visual inspection. This method of detecting faint sources is dependent on the accuracy of the sky subtraction.

  14. Passive Evolution: Are the Faint Blue Galaxy Counts Produced by a Population of Eternally Young Galaxies?

    NASA Astrophysics Data System (ADS)

    Bouwens, Rychard J.; Silk, Joseph

    1996-11-01

    A constant-age population of blue galaxies, postulated in the model of Gronwall & Koo, seems to provide an attractive explanation of the excess of very blue galaxies in the deep galaxy counts. Such a population may be generated by a set of galaxies with cycling star formation rates or, at the other extreme, be maintained by the continual formation of new galaxies that fade after they reach the age specified in the Gronwall & Koo model. For both of these hypotheses, we have calculated the luminosity functions, including the respective selection criteria, the redshift distributions, and the number counts in the BJ and K bands. We find a substantial excess in the number of galaxies at low redshift (0 < z < 0.05) over that observed in the Canada-France-Hawaii redshift survey (Lilly et al.) and at the faint end of the Las Campanas luminosity function (Lin et al.). Passive or mild evolution fails to account for the deep galaxy counts because of the implications for low-redshift determinations of the I-selected redshift distribution and the r-selected luminosity function in samples where the faded counterparts of the star-forming galaxies would be detectable.

  15. Archean Earth Atmosphere Fractal Haze Aggregates: Light Scattering Calculations and the Faint Young Sun Paradox

    NASA Astrophysics Data System (ADS)

    Boness, D. A.; Terrell-Martinez, B.

    2010-12-01

    As part of an ongoing undergraduate research project of light scattering calculations involving fractal carbonaceous soot aggregates relevant to current anthropogenic and natural sources in Earth's atmosphere, we have read with interest a recent paper [E.T. Wolf and O.B Toon,Science 328, 1266 (2010)] claiming that the Faint Young Sun paradox discussed four decades ago by Carl Sagan and others can be resolved without invoking heavy CO2 concentrations as a greenhouse gas warming the early Earth enough to sustain liquid water and hence allow the origin of life. Wolf and Toon report that a Titan-like Archean Earth haze, with a fractal haze aggregate nature due to nitrogen-methane photochemistry at high altitudes, should block enough UV light to protect the warming greenhouse gas NH3 while allowing enough visible light to reach the surface of the Earth. To test this hypothesis, we have employed a rigorous T-Matrix arbitrary-particle light scattering technique, to avoid the simplifications inherent in Mie-sphere scattering, on haze fractal aggregates at UV and visible wavelenths of incident light. We generate these model aggregates using diffusion-limited cluster aggregation (DLCA) algorithms, which much more closely fit actual haze fractal aggregates than do diffusion-limited aggregation (DLA) algorithms.

  16. Herschel Discovery of a New Class of Cold, Faint Debris Discs

    NASA Technical Reports Server (NTRS)

    Eiroal, C.; Marshall, J. P.; Mora, A.; Krivov, A. V.; Montesinos, B.; Absil, O.; Ardila, D.; Arevalo, M.; Augereau, J.-Ch.; Bayo, A.; Danchi, W.; del Burgo, C.; Ertel, S.; Fridlund, M.; Gonzalez-Garcia, B. M.; Heras, A. M.; Lebreton, J.; Liseau, R.; Maldonado, J.; Meeus, G.; Montes, D.; Pilbratt, G. L.; Roberge, A.; Sanz-Forcada, J.; Stapelfeldt, K.

    2011-01-01

    We present Herschel PACS 100 and 160 micron observations of the solar-type stars alpha Men, HD 88230 and HD 210277, which form part of the FGK stars sample of the Herschel Open Time Key Programme (OTKP) DUNES (DUst around NEarby Stars). Our observations show small infrared excesses at 160 m for all three stars. HD 210277 also shows a small excess at 100 micron, while the 100 micron fluxes of alpha Men and HD 88230 agree with the stellar photospheric predictions. We attribute these infrared excesses to a new class of cold, faint debris discs. alpha Men and HD 88230 are spatially resolved in the PACS 160 m images, while HD 210277 is point-like at that wavelength. The projected linear sizes of the extended emission lie in the range from approx 115 to <= 250 AU. The estimated black body temperatures from the 100 and 160 micron fluxes are approx < 22 K, while the fractional luminosity of the cold dust is L(sub dust) / L(*) approx 10 (exp 6) close to the luminosity of the Solar-System's Kuiper belt. These debris discs are the coldest and faintest discs discovered so far around mature stars and cannot easily be explained by invoking "classical" debris disc models.

  17. Herschel Discovery of a New class of Cold, Faint Debris Discs

    NASA Technical Reports Server (NTRS)

    Eiroa, C.; Marshall, J. P.; Mora, A.; Krivov, A. V.; Montesinos, B.; Absil, O.; Ardila, D.; Arevalo, M.; Augereau, J. -Ch.; Bayo, A.; Danchi, W.; del Burgo, C.; Ertel, S.; Fridlund, M.; Gonzalez-Garcia, B. M.; Heras, A. M.; Lebreton, J.; Liseau, R.; Maldonado, J.; Meeus, G.; Montes, D.; Pilbratt, G. L.; Roberge, A.; Sanz-Forcada, J.; Stapelfeldt, K.

    2012-01-01

    We present Herschel PACS 100 and 160 micron observations of the solar-type stars alpha Men, HD 88230 and HD 210277, which form part of the FGK stars sample of the Herschel Open Time Key Programme (OTKP) DUNES (DUst around NEarby Stars). Our observations show small infrared excesses at 160 micron for all three stars. HD 210277 also shows a small excess at 100 micron. while the 100 micron fluxes of a Men and HD 88230 agree with the stellar photospheric predictions. We attribute these infrared excesses to a new class of cold, faint debris discs. alpha Men and HD 88230 are spatially resolved in the PACS 160 micron images, while HD 210277 is point-like at that wavelength. The projected linear sizes of the extended emission lie in the range from approximately 115 to <= 250 AU. The estimated black body temperatures from the 100 and 160 micron fluxes are approximately < 22 K, while the fractional luminosity of the cold dust is L(dust)/ L(star) approximates 10(exp -6), close to the luminosity of the Solar-System's Kuiper belt. These debris discs are the coldest and faintest discs discovered so far around mature stars and cannot easily be explained by invoking "classical" debris disc models.

  18. The nature of very faint X-ray binaries: hints from light curves

    NASA Astrophysics Data System (ADS)

    Heinke, C. O.; Bahramian, A.; Degenaar, N.; Wijnands, R.

    2015-03-01

    Very faint X-ray binaries (VFXBs), defined as having peak luminosities LX of 1034-1036 erg s-1, have been uncovered in significant numbers, but remain poorly understood. We analyse three published outburst light curves of two transient VFXBs using the exponential and linear decay formalism of King & Ritter. The decay time-scales and brink luminosities suggest orbital periods of order 1 h. We review various estimates of VFXB properties, and compare these with suggested explanations of the nature of VFXBs. We suggest that: (1) VFXB outbursts showing linear decays might be explained as partial drainings of the disc of `normal' X-ray transients, and many VFXB outbursts may belong to this category; (2) VFXB outbursts showing exponential decays are best explained by old, short-period systems involving mass transfer from a low-mass white dwarf or brown dwarf; (3) persistent (or quasi-persistent) VFXBs, which maintain an LX of 1034-1035 erg s-1 for years, may be explained by magnetospheric choking of the accretion flow in a propeller effect, permitting a small portion of the flow to accrete on to the neutron star's surface. We thus predict that (quasi-) persistent VFXBs may also be transitional millisecond pulsars, turning on as millisecond radio pulsars when their LX drops below 1032 erg s-1.

  19. Astrometric and Photometric Follow-Up of Faint Near Earth Objects

    NASA Technical Reports Server (NTRS)

    Spahr, Timothy

    2004-01-01

    During the last year, the Near-Earth Object (NEO) follow-up program at Mt. Hopkins funded by the Near-Earth Object Observations (NEOO) program continued to improve. The Principal Investigator was again granted all the requested observing time. In addition to the requested time on the 4 8 in. telescope, 2 nights were also granted on the MMT for observations of extremely faint main-belt asteroids and NEOs. It is expected that the MMT can easily reach V = 25 over a 24 X 24 arcminute field of view. Improvements in the last year included more tweaks to the automatic astrometric routine for higher-quality astrometric fits. Use of the new USNO-B1.0 reference catalog has allowed the PI to push the average RMS of reference star solutions below 0.2 in.. Shift-and- stack techniques are used to improve the signal-to-noise ratio of the target objects. The 48 in. telescope at Mt. Hopkins is completely automated, and can be run remotely from either the Principal Investigator's office at SAO, or even his study at home. Most observing runs are now done remotely.

  20. STAR FORMATION IN ULTRA-FAINT DWARFS: CONTINUOUS OR SINGLE-AGE BURSTS?

    SciTech Connect

    Webster, David; Bland-Hawthorn, Joss; Sutherland, Ralph

    2015-01-30

    We model the chemical evolution of six ultra-faint dwarfs (UFDs): Bootes I, Canes Venatici II, Coma Berenices, Hercules, Leo IV, and Ursa Major I based on their recently determined star formation histories. We show that two single-age bursts cannot explain the observed [α/Fe] versus [Fe/H] distribution in these galaxies and that some self-enrichment is required within the first burst. An alternative scenario is modeled, in which star formation is continuous except for short interruptions when one or more supernovae temporarily blow the dense gas out from the center of the system. This model allows for self-enrichment and can reproduce the chemical abundances of the UFDs in which the second burst is only a trace population. We conclude that the most likely star formation history is one or two extended periods of star formation, with the first burst lasting for at least 100 Myr. As found in earlier work, the observed properties of UFDs can be explained by formation at a low mass (M{sub vir}∼10{sup 7} M{sub ⊙}), rather than being stripped remnants of much larger systems.

  1. A faint type of supernova from a white dwarf with a helium-rich companion

    NASA Astrophysics Data System (ADS)

    Perets, H. B.; Gal-Yam, A.; Mazzali, P. A.; Arnett, D.; Kagan, D.; Filippenko, A. V.; Li, W.; Arcavi, I.; Cenko, S. B.; Fox, D. B.; Leonard, D. C.; Moon, D.-S.; Sand, D. J.; Soderberg, A. M.; Anderson, J. P.; James, P. A.; Foley, R. J.; Ganeshalingam, M.; Ofek, E. O.; Bildsten, L.; Nelemans, G.; Shen, K. J.; Weinberg, N. N.; Metzger, B. D.; Piro, A. L.; Quataert, E.; Kiewe, M.; Poznanski, D.

    2010-05-01

    Supernovae are thought to arise from two different physical processes. The cores of massive, short-lived stars undergo gravitational core collapse and typically eject a few solar masses during their explosion. These are thought to appear as type Ib/c and type II supernovae, and are associated with young stellar populations. In contrast, the thermonuclear detonation of a carbon-oxygen white dwarf, whose mass approaches the Chandrasekhar limit, is thought to produce type Ia supernovae. Such supernovae are observed in both young and old stellar environments. Here we report a faint type Ib supernova, SN 2005E, in the halo of the nearby isolated galaxy, NGC 1032. The `old' environment near the supernova location, and the very low derived ejected mass (~0.3 solar masses), argue strongly against a core-collapse origin. Spectroscopic observations and analysis reveal high ejecta velocities, dominated by helium-burning products, probably excluding this as a subluminous or a regular type Ia supernova. We conclude that it arises from a low-mass, old progenitor, likely to have been a helium-accreting white dwarf in a binary. The ejecta contain more calcium than observed in other types of supernovae and probably large amounts of radioactive 44Ti.

  2. The faint end of the 250 μm luminosity function at z < 0.5

    NASA Astrophysics Data System (ADS)

    Wang, L.; Norberg, P.; Bethermin, M.; Bourne, N.; Cooray, A.; Cowley, W.; Dunne, L.; Dye, S.; Eales, S.; Farrah, D.; Lacey, C.; Loveday, J.; Maddox, S.; Oliver, S.; Viero, M.

    2016-08-01

    Aims: We aim to study the 250 μm luminosity function (LF) down to much fainter luminosities than achieved by previous efforts. Methods: We developed a modified stacking method to reconstruct the 250 μm LF using optically selected galaxies from the SDSS survey and Herschel maps of the GAMA equatorial fields and Stripe 82. Our stacking method not only recovers the mean 250 μm luminosities of galaxies that are too faint to be individually detected, but also their underlying distribution functions. Results: We find very good agreement with previous measurements in the overlapping luminosity range. More importantly, we are able to derive the LF down to much fainter luminosities (~ 25 times fainter) than achieved by previous studies. We find strong positive luminosity evolution L*250(z)∝(1+z)4.89±1.07 and moderate negative density evolution Φ*250(z)∝(1+z)-1.02±0.54 over the redshift range 0.02

  3. The faint young Sun paradox: an observational test of an alternative solar model

    NASA Technical Reports Server (NTRS)

    Gaidos, E. J.; Gudel, M.; Blake, G. A.

    2000-01-01

    We report the results of deep observations at radio (3.6 cm) wavelengths of the nearby solar-type star pi 01 Ursa Majoris with the Very Large Array (VLA) intended to test an alternative theory of solar luminosity evolution. The standard model predicts a solar luminosity only 75% of the present value and surface temperatures below freezing on Earth and Mars at 4 Ga, seemingly in conflict with geologic evidence for liquid water on these planets. An alternative model invokes a compensatory mass loss through a declining solar wind that results in a more consistent early luminosity. The free-free emission from an enhanced wind around nearby young Sun-like stars should be detectable at microwave frequencies. Our observations of pi 01 UMa, a 300 million year-old solar-mass star, place an upper limit on the mass loss rate of 4-5 x 10(-11) M(solar) yr-1. Total mass loss from such a star over 4 Gyr would be less than 6%. If this star is indeed an analog of the early Sun, it casts doubt on the alternative model as a solution to the faint young Sun paradox, particularly for Mars.

  4. Extragalactic Radio Astronomy from an Armchair: Continuum Spectral Shapes of 150 Faint Sources

    NASA Astrophysics Data System (ADS)

    Gonzalez-Perez, J. N.; Andernach, H.

    1994-08-01

    We have used all available radio-source surveys to construct the continuum spectra for sources in an area of 5 by 10 degrees near the North Ecliptic Pole (NEP), previously observed at 2.7 GHz with the Effelsberg telescope. Most of the surveys are of similar angular resolution (~3 to 5 arcmin) and cover a wide range of frequencies from 38 MHz to 5 GHz. We have developed a cross-identification algorithm that takes into account the dependence of source structure on observing frequency. This improved the number of true matches between the source catalogues. Spectra for 229 sources with flux measurements at two or more frequencies were constructed. For 124 of these we found data at four or more frequencies, allowing us to classify their spectral shape. In our rather faint sample (S_2.7GHz > 20 mJy) we find the fraction of sources with spectral curvature to be much lower than in samples of stronger sources previously studied by other authors. Preliminary optical identifications are being drawn from the digitized versions of the first Palomar Sky Survey prepared at STScI.

  5. The quenching of the ultra-faint dwarf galaxies in the reionization era

    SciTech Connect

    Brown, Thomas M.; Tumlinson, Jason; Kalirai, Jason S.; Avila, Roberto J.; Gennaro, Mario; Ferguson, Henry C. E-mail: tumlinson@stsci.edu E-mail: avila@stsci.edu E-mail: gennaro@stsci.edu; and others

    2014-12-01

    We present new constraints on the star formation histories of six ultra-faint dwarf galaxies: Bootes I, Canes Venatici II, Coma Berenices, Hercules, Leo IV, and Ursa Major I. Our analysis employs a combination of high-precision photometry obtained with the Advanced Camera for Surveys on the Hubble Space Telescope, medium-resolution spectroscopy obtained with the DEep Imaging Multi-Object Spectrograph on the W. M. Keck Observatory, and updated Victoria-Regina isochrones tailored to the abundance patterns appropriate for these galaxies. The data for five of these Milky Way satellites are best fit by a star formation history where at least 75% of the stars formed by z ∼ 10 (13.3 Gyr ago). All of the galaxies are consistent with 80% of the stars forming by z ∼ 6 (12.8 Gyr ago) and 100% of the stars forming by z ∼ 3 (11.6 Gyr ago). The similarly ancient populations of these galaxies support the hypothesis that star formation in the smallest dark-matter sub-halos was suppressed by a global outside influence, such as the reionization of the universe.

  6. Isophotal shapes of early-type galaxies to very faint levels

    SciTech Connect

    Chaware, Laxmikant; Pandey, S. K.; Cannon, Russell; Kembhavi, Ajit K.; Mahabal, Ashish

    2014-06-01

    We report on a study of the isophotal shapes of early-type galaxies to very faint levels, reaching ∼0.1% of the sky brightness. The galaxies are from the Large Format Camera (LFC) fields obtained using the Palomar 5 m Hale Telescope, with integrated exposures ranging from 1 to 4 hr in the Sloan Digital Sky Survey r, i, and z bands. The shapes of isophotes of early-type galaxies are important, as they are correlated with the physical properties of the galaxies and are influenced by galaxy formation processes. In this paper, we report on a sample of 132 E and SO galaxies in one LFC field. We have redshifts for 53 of these, obtained using AAOmega on the Anglo-Australian Telescope. The shapes of early-type galaxies often vary with radius. We derive average values of isophotal shape parameters in four different radial bins along the semi-major axis in each galaxy. We obtain empirical fitting formulae for the probability distribution of the isophotal parameters in each bin and investigate for possible correlations with other global properties of the galaxies. Our main finding is that the isophotal shapes of the inner regions are statistically different from those in the outer regions. This suggests that the outer and inner parts of early-type galaxies have evolved somewhat independently.

  7. Faint Object Camera observations of M87 - The jet and nucleus

    NASA Technical Reports Server (NTRS)

    Boksenberg, A.; Macchetto, F.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Crane, P.; Deharveng, J. M.; Disney, M. J.; Jakobsen, P.; Kamperman, T. M.

    1992-01-01

    UV and optical images of the central region and jet of the nearby elliptical galaxy M87 have been obtained with about 0.1 arcsec resolution in several spectral bands with the Faint Object Camera (FOC) on the HST, including polarization images. Deconvolution enhances the contrast of the complex structure and filamentary patterns in the jet already evident in the aberrated images. Morphologically there is close similarity between the FOC images of the extended jet and the best 2-cm radio maps obtained at similar resolution, and the magnetic field vectors from the UV and radio polarimetric data also correspond well. We observe structure in the inner jet within a few tenths arcsec of the nucleus which also has been well studied at radio wavelengths. Our UV and optical photometry of regions along the jet shows little variation in spectral index from the value 1.0 between markedly different regions and no trend to a steepening spectrum with distance along the jet.

  8. Ultra-light dark matter in ultra-faint dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Calabrese, Erminia; Spergel, David N.

    2016-08-01

    Cold Dark Matter (CDM) models struggle to match the observations at galactic scales. The tension can be reduced either by dramatic baryonic feedback effects or by modifying the particle physics of CDM. Here, we consider an ultra-light scalar field DM particle manifesting a wave nature below a DM particle mass-dependent Jeans scale. For DM mass m ˜ 10-22 eV, this scenario delays galaxy formation and avoids cusps in the centre of the dark matter haloes. We use new measurements of half-light mass in ultra-faint dwarf galaxies Draco II and Triangulum II to estimate the mass of the DM particle in this model. We find that if the stellar populations are within the core of the density profile then the data are in agreement with a Wave Dark Matter model having a DM particle with m ˜ 3.7-5.6 × 10-22 eV. The presence of this extremely light particle will contribute to the formation of a central solitonic core replacing the cusp of a Navarro-Frenk-White profile and bringing predictions closer to observations of cored central density in dwarf galaxies.

  9. A Search for Faint, Diffuse Halo Emission in Edge-On Galaxies with Spitzer/IRAC

    NASA Astrophysics Data System (ADS)

    Ashby, Matthew; Arendt, R. G.; Pipher, J. L.; Forrest, W. J.; Marengo, M.; Barmby, P.; Willner, S. P.; Stauffer, J. R.; Fazio, G. G.

    2006-12-01

    We present deep infrared mosaics of the nearby edge-on spiral galaxies NGC 891, 4244, 4565, and 5907. These data were acquired at 3.6, 4.5, 5.8, and 8.0 microns using the Infrared Array Camera aboard Spitzer as part of GTO program number 3. This effort is designed to detect the putative faint, diffuse emission from halos and thick disks of spiral galaxies in the near-mid infrared under the thermally stable, low-background conditions of space. These conditions in combination with the advantageous viewing angles presented by these well-known edge-on spirals provide arguably the best opportunity to characterize the halo/thick disk components of such galaxies in the infrared. In this contribution we describe our observations, data reduction techniques, corrections for artifacts in the data, and the modeling approach we applied to analyze this unique dataset. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech.

  10. A search for AGN activity in Infrared-Faint Radio Sources (IFRS)

    NASA Astrophysics Data System (ADS)

    Lenc, Emil; Middelberg, Enno; Norris, Ray; Mao, Minnie

    2009-04-01

    We propose to observe a large sample of radio sources from the ATLAS (Australia Telescope Large Area Survey) source catalogue with the LBA, to determine their compactness. The sample consists of 36 sources with no counterpart in the co-located SWIRE survey (3.6 um to 160 um), carried out with the Spitzer Space Telescope. This rare class of sources, dubber Infrared-Faint Radio Sources (IFRS), is inconsistent with current galaxy evolution models. VLBI observations are an essential way to obtain further clues on what these objects are and why they are hidden from infrared observations. We will measure the flux densities on long baselines to determine their compactness. Only five IFRS have been previously targeted with VLBI observations (resulting in two detections). We propose using single baseline (Parkes-ATCA) eVLBI observations with the LBA at 1 Gbps to maximise sensitivity. With the observations proposed here we will increase the number of VLBI-observed IFRS from 5 to 36, allowing us to draw statistical conclusions about this intriguing new class of objects.

  11. The first VLBI image of an infrared-faint radio source

    NASA Astrophysics Data System (ADS)

    Middelberg, E.; Norris, R. P.; Tingay, S.; Mao, M. Y.; Phillips, C. J.; Hotan, A. W.

    2008-11-01

    Context: We investigate the joint evolution of active galactic nuclei and star formation in the Universe. Aims: In the 1.4 GHz survey with the Australia Telescope Compact Array of the Chandra Deep Field South and the European Large Area ISO Survey - S1 we have identified a class of objects which are strong in the radio but have no detectable infrared and optical counterparts. This class has been called Infrared-Faint Radio Sources, or IFRS. 53 sources out of 2002 have been classified as IFRS. It is not known what these objects are. Methods: To address the many possible explanations as to what the nature of these objects is we have observed four sources with the Australian Long Baseline Array. Results: We have detected and imaged one of the four sources observed. Assuming that the source is at a high redshift, we find its properties in agreement with properties of Compact Steep Spectrum sources. However, due to the lack of optical and infrared data the constraints are not particularly strong.

  12. A search for AGN activity in Infrared-Faint Radio Sources (IFRS)

    NASA Astrophysics Data System (ADS)

    Lenc, Emil; Middelberg, Enno; Norris, Ray; Mao, Minnie

    2010-04-01

    We propose to observe a large sample of radio sources from the ATLAS (Australia Telescope Large Area Survey) source catalogue with the LBA, to determine their compactness. The sample consists of 36 sources with no counterpart in the co-located SWIRE survey (3.6 um to 160 um), carried out with the Spitzer Space Telescope. This rare class of sources, dubber Infrared-Faint Radio Sources (IFRS), is inconsistent with current galaxy evolution models. VLBI observations are an essential way to obtain further clues on what these objects are and why they are hidden from infrared observations. We will measure the flux densities on long baselines to determine their compactness. Only five IFRS have been previously targeted with VLBI observations (resulting in two detections). We propose using single baseline (Parkes-ATCA) eVLBI observations with the LBA at 1 Gbps to maximise sensitivity. With the observations proposed here we will increase the number of VLBI-observed IFRS from 5 to 36, allowing us to draw statistical conclusions about this intriguing new class of objects.

  13. First results from the Faint Object Camera - Imaging the core of R Aquarii

    NASA Technical Reports Server (NTRS)

    Paresce, F.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.

    1991-01-01

    The Faint Object Camera on the HST was pointed toward the symbiotic long-period M7e Mira variable R Aquarii, and very high resolution images of the inner core, mainly in the ionized oxygen emission lines in the optical, are reported. Both images show bright arcs, knots, and filaments superposed on a fainter, diffuse nebulosity extending in a general SW-NE direction from the variable to the edge of the field at 10 arcsec distance. The core is resolved in forbidden O III 5007 A and forbidden O II 3727 A into at least two bright knots of emission whose positions and structures are aligned with PA = 50 deg. The central knots appear to be the source of a continuous, well-collimated, stream of material extending out to 3-4 arcsec in the northern sector corresponding to a linear distance of about 1000 AU. The northern stream seems to bend around an opaque obstacle and form a spiral before breaking up into wisps and knots. The southern stream is composed of smaller, discrete parcels of emitting gas curving to the SE.

  14. Rapidly evolving faint transients from stripped-envelope electron-capture supernovae

    NASA Astrophysics Data System (ADS)

    Moriya, Takashi J.; Eldridge, J. J.

    2016-09-01

    We investigate the expected rates and bolometric light-curve properties of stripped-envelope electron-capture supernovae (ECSNe) using stellar models from the Binary Population and Spectral Synthesis code. We find that 0.8 per cent (Z = 0.020) and 1.2 per cent (Z = 0.004) of core-collapse supernovae are stripped-envelope ECSNe. Their typical ejecta masses are estimated to be about 0.3 M⊙(Z = 0.020) and 0.6 M⊙ (Z = 0.004). Assuming ECSN explosion properties from numerical explosion simulations, an explosion energy of 1.5 × 1050 erg and a 56Ni mass of 2.5 × 10-3 M⊙, we find that stripped-envelope ECSNe have a typical rise time of around 7 d (Z = 0.020) or 13 d (Z = 0.004) and peak luminosity of around 1041 ergs-1 (-13.8 mag, Z = 0.020) or 7 × 1040 erg s-1 (-13.4 mag, Z = 0.004). Their typical ejecta velocities are around 7000 km s-1 (Z = 0.020) or 5000 km s-1 (Z = 0.004). Thus, stripped-envelope ECSNe are observed as rapidly evolving faint transients with relatively small velocities. SN 2008ha-like supernovae, which are the faintest kind of SN 2002cx-like (also known as Type Iax) supernovae, may be related to stripped-envelope ECSNe.

  15. Exploring Faint, Large-Scale Filaments in the Warm Ionized Medium of the Galaxy

    NASA Astrophysics Data System (ADS)

    Madsen, G. J.; Reynolds, R. J.; Haffner, L. M.

    2002-05-01

    We have used the Wisconsin Hα Mapper (WHAM) to investigate the properties of faint, large-scale Hα -emitting filaments in the warm ionized medium of the Galaxy. The recent WHAM Northern Sky Survey has revealed several of these remarkable features, some of which may extend over 1 kpc above the Galactic plane. In an effort to understand the origin and physical conditions of these structures, we have obtained optical emission line spectra toward a collection of filaments in Hα , Hβ , [N 2], [S 2], He 1, and [O 3]. These filaments include a 60o-long vertical structure which rises above the CMa R1 OB association in the plane, a horizontal feature that stretches 20o perpendicular to this larger filament, and an isolated filament extending 5o near the Lockman window at high Galactic latitude. The temperature, density, extinction, kinematics, and ionization state of these filaments, as revealed by their spectra, is discussed. We also compare the physical conditions within these filaments to classical H 2 regions and speculate on their origin. This work has been supported by the National Science Foundation through grant AST 96-19424.

  16. Ultra-light dark matter in ultra-faint dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Calabrese, Erminia; Spergel, David N.

    2016-08-01

    Cold Dark Matter (CDM) models struggle to match the observations at galactic scales. The tension can be reduced either by dramatic baryonic feedback effects or by modifying the particle physics of CDM. Here, we consider an ultra-light scalar field DM particle manifesting a wave nature below a DM particle mass-dependent Jeans scale. For DM mass $m\\sim10^{-22}{\\rm eV}$, this scenario delays galaxy formation and avoids cusps in the center of the dark matter haloes. We use new measurements of half-light mass in ultra-faint dwarf galaxies Draco II and Triangulum II to estimate the mass of the DM particle in this model. We find that if the stellar populations are within the core of the density profile then the data are in agreement with a wave dark matter model having a DM particle with $m\\sim 3.7-5.6\\times 10^{-22}{\\rm eV}$. The presence of this extremely light particle will contribute to the formation of a central solitonic core replacing the cusp of a Navarro-Frenk-White profile and bringing predictions closer to observations of cored central density in dwarf galaxies.

  17. Robotic telescope systems for CCD photometry of faint objects in crowded fields

    NASA Astrophysics Data System (ADS)

    Baruch, John E.; da Luz Vieira, Janice

    1993-11-01

    This paper first considers the design of robotic telescopes to monitor faint objects in crowded fields. It shows that the mechanical design problems have been solved by the use of precision control and modelling software developed for the latest large telescopes. Modern design methods mean that these telescopes can be produced relatively cheaply. The largest part of the cost of a robotic telescope is the software to enable it to work as an autonomous robot. Conventional software techniques are inadequate and inefficient for many purposes associated with robotic operation. These include: to optimize and monitor their operation and efficiency, to schedule their observing, to evaluate their environment, to generate confidence in the target acquisition pattern recognition parameters, to evaluate the quality of the CCD images and the photometry of the objects within the images, and to return reduced data to the astronomer with the required indices to gives the astronomer confidence in the data. The paper evaluates AI, neural nets and fuzzy logic techniques applied to these different problems.

  18. Infrared guiding with faint stars with the wide-field infrared camera at CFHT

    NASA Astrophysics Data System (ADS)

    Teeple, Douglas; Riopel, Martin; Baril, Marc; Barrick, Gregory; Albert, Loic; Vermeulen, Tom; Ward, Jeff

    2006-06-01

    The Canada-France-Hawaii Telescope (CFHT) is commissioning a new Wide field Infrared Camera (WIRCam) that uses a mosaic of 4 HAWAII-2RG near- infrared detectors manufactured by Rockwell. At the heart of the instrument is an On-Chip Guiding System (OCGS) that exploits the unique parallel science/guide frame readout capability of the HAWAII-2RG detectors. A small sub sample of each array is continuously read at a rate of up to 50 Hz while the integration of the science image is ongoing with the full arrays (read at a maximal rate of 1.4 s per full frame). Each of these guiding windows is centered on a star to provide an error signal for the telescope guiding. An Image Stabilizer Unit (ISU) (i.e. a tip-tilt silica plate), provides the corrections. A Proportional Integral Differential (PID) closed loop controls the ISU such that telescope tracking is corrected at a rate of 5 Hz. This paper presents the technical architecture of the guiding system and performance measurements on the sky in engineering runs with WIRCam with faint stars up to magnitude 14.

  19. VizieR Online Data Catalog: Infrared-faint radio sources catalog (Collier+, 2014)

    NASA Astrophysics Data System (ADS)

    Collier, J. D.; Banfield, J. K.; Norris, R. P.; Schnitzeler, D. H. F. M.; Kimball, A. E.; Filipovic, M. D.; Jarrett, T. H.; Lonsdale, C. J.; Tothill, N. F. H.

    2014-11-01

    The 20cm radio data come from the Unified Radio Catalog (URC) compiled by Kimball & Ivezic (2008AJ....136..684K). This radio catalogue combines data from the National Radio Astronomy Observatory (NRAO) VLA Sky Survey (NVSS; Condon et al., 1998, Cat. VIII/65), Faint Images of the Radio Sky at Twenty Centimeters (FIRST; Becker, White & Helfand, 1995, cat. VIII/92), Green Bank 6cm survey (GB6; Gregory et al., 1996, Cat. VIII/40), the Westerbork Northern Sky Survey (WENSS; Rengelink et al. 1997; de Bruyn et al. 2000, Cat. VIII/62) and the Sloan Digital Sky Survey Data Release 6 (SDSS DR6; Adelman-McCarthy et al., 2008, Cat. II/282). We use updated NVSS and FIRST data from the URC version 2.0 (Kimball & Ivezic, in preparation), which includes a number of new sources as well as updated positions and flux densities. The IR data come from WISE (Wright et al. (WISE Team) 2009, Cat. II/311), which is an all-sky survey centred at 3.4, 4.6, 12 and 22um (referred to as bands W1, W2, W3 and W4), with respective angular resolutions of 6.1, 6.4, 6.5 and 12.0-arcsec (full width at half-maximum, FWHM), and typical 5σ sensitivity levels of 0.08, 0.11, 1 and 6mJy, with sensitivity increasing towards the ecliptic poles. (1 data file).

  20. Reviving red snapper.

    PubMed

    Estabrook, Barry

    2010-01-01

    Red snappers in the Gulf of Mexico once hovered on the brink of extinction, their population having dropped to 2 percent of what had historically swum in the Gulf. But thanks to a recently introduced plan that turns the conventional wisdom of fisheries management on its head, the picture has begun to change. Called Individual Fishing Quotas (IFQs), the new regulations, which give a guaranteed allotment of fish to each participant instead of applying industry-wide quotas, went into effect for Gulf of Mexico Red Snapper (Lutjanus campechanus) in early 2007. The results were immediate and so profound that the Gulf Fishery Management Council voted earlier this year to increase the annual limit on red snapper to nearly 7 million pounds from 5 million. PMID:21542214

  1. Red-based cumulus.

    PubMed

    Gedzelman, Stanley David

    2015-02-01

    Observations and model simulations of cumulus clouds whose bases are tinted red when the Sun is well above the horizon are presented. Conditions for seeing red bases include (1) a red underlying surface (which may consist of dust clouds, as from haboobs) with high albedo, (2) small fractional cloud cover when the Sun is far enough below the zenith for direct sunlight to illuminate much of the surface directly below and around cloud base, (3) optically thick clouds so that the bases are dark, and (4) clouds with bases that are near enough to the observer to appear high in the sky so that the admixture of scattered light from the intervening atmosphere is minimized. PMID:25967822

  2. The Origin of Intermediate-Luminosity Red Transients

    NASA Astrophysics Data System (ADS)

    Bond, Howard

    2014-10-01

    Intermediate-luminosity red transients (ILRTs) are a new class of optical transients. They have maximum luminosities between novae and SNe, and outbursts lasting several months, becoming cool, dusty, and extremely red as the eruptions proceed. A prototype is V838 Mon, which illuminated a spectacular light echo. Their outbursts may be due to catastrophic stellar collisions and mergers. This is demonstrably true for V1309 Sco, which was a contact binary before its eruption and is now a single star. However, it is not yet clear whether all ILRTs are due to mergers.I propose WFC3 imaging of 3 ILRTs: (1) V4332 Sgr, which erupted in the Galactic bulge in 1994, is now a 19th-mag, very red remnant. Based on a high degree of linear polarization in ground-based measurements, it has been proposed that it is surrounded and obscured by a dusty, edge-on envelope, ejected during a stellar merger. If so, V4332 Sgr ought to display a dark lane at HST imaging resolution. (2) M31 RV is an ILRT that occurred in the bulge of M31 in 1988. HST images of the site taken between 1999 and 2010 failed to reveal a credible remnant of this event. However, models of expanding dusty envelopes predict that eventually, as the optical depth diminishes, the remnant should brighten. The passage of 5 years since the last HST observation of the field justifies another attempt to identify the putative merged binary. (3) CK Vul, the bright "nova" of 1670, is a candidate ILRT because of its red color and an outburst light curve resembling that of V838 Mon. A faint bipolar nebula lies at the site of CK Vul, but no credible remnant star has been found in ground-based images. HST resolution may reveal it.

  3. An extreme-AO search for giant planets around a white dwarf. VLT/SPHERE performance on a faint target GD 50

    NASA Astrophysics Data System (ADS)

    Xu, S.; Ertel, S.; Wahhaj, Z.; Milli, J.; Scicluna, P.; Bertrang, G. H.-M.

    2015-07-01

    Context. Little is known about the planetary systems around single white dwarfs, although there is strong evidence that they do exist. Aims: We performed a pilot study with the extreme-AO system on the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) on the Very Large Telescopes (VLT) to look for giant planets around a young white dwarf, GD 50. Methods: We were awarded science verification time on the new ESO instrument SPHERE. Observations were made with the InfraRed Dual-band Imager and Spectrograph in classical imaging mode in H band. Results: Despite the faintness of the target (14.2 mag in R band), the AO loop was closed and a strehl of 37% was reached in H band. No objects were detected around GD 50. We achieved a 5-sigma contrast of 6.2, 8.0, and 8.25 mag at 0.̋2, 0.̋4, and 0.̋6 and beyond, respectively. We exclude any substellar objects more massive than 4.0 MJ at 6.2 au, 2.9 MJ at 12.4 au, and 2.8 MJ at 18.6 au and beyond. This rivals the previous upper limit set by Spitzer. We further show that SPHERE is the most promising instrument available to search for close-in substellar objects around nearby white dwarfs. Based on observations made with European Southern Observatory (ESO) telescopes at the La Silla Paranal Observatory under program 60.A-9373(A).Figure 4 is available in electronic form at http://www.aanda.org

  4. Lustre on Red Sky.

    SciTech Connect

    Monk, Stephen Todd; Mervini, Joe

    2010-04-01

    The goals of Lustre on Red Sky are: (1) provide home/projects/scratch Lustre file systems; (2) adhere to the Sun HPC stack; (3) implement software RAID on Sun provided JBODs; and (4) design for easy administration. Conclusions are: (1) software RAID includes additional risks and administration vs. hardware RAID solutions; (2) limited testing of hardware in these configurations make it ill-suited for rapid deployment in a production environment; and (3) Lustre has been a shining star on this machine, Red Sky users are pleased with its performance.

  5. What does an erupting nova do to its red dwarf companion

    SciTech Connect

    Kovetz, A.; Prialnik, D.; Shara, M.M.

    1988-02-01

    During nova eruptions and for decades afterward, the red dwards in cataclysmic binaries are irradiated with hundreds of times more luminosity than they themselves produce. Simulations of the time-dependent irradiation of three red dwarf models (0.25, 0.50, and 0.75 solar mass) are presented. The mass transfer rates forced by irradiation after nova eruption are found to be enhanced by two orders of magnitude because of the irradiation. The time scale for irradiation to become unimportant is that of the white dwarf cooling time scale, a few centuries. These two results support the hibernation scenario of novae, which suggests that novae remain bright for a few centuries after eruption because of irradiation-induced mass transfer. After irradiation decreases mass transfer slows, and some very old novae may then become extremely faint. 26 references.

  6. High-resolution imaging of the Pluto-Charon system with the Faint Object Camera of the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Albrecht, R.; Barbieri, C.; Adorf, H.-M.; Corrain, G.; Gemmo, A.; Greenfield, P.; Hainaut, O.; Hook, R. N.; Tholen, D. J.; Blades, J. C.

    1994-01-01

    Images of the Pluto-Charon system were obtained with the Faint Object Camera (FOC) of the Hubble Space Telescope (HST) after the refurbishment of the telescope. The images are of superb quality, allowing the determination of radii, fluxes, and albedos. Attempts were made to improve the resolution of the already diffraction limited images by image restoration. These yielded indications of surface albedo distributions qualitatively consistent with models derived from observations of Pluto-Charon mutual eclipses.

  7. Sweating the small stuff: simulating dwarf galaxies, ultra-faint dwarf galaxies, and their own tiny satellites

    NASA Astrophysics Data System (ADS)

    Wheeler, Coral; Oñorbe, Jose; Bullock, James S.; Boylan-Kolchin, Michael; Elbert, Oliver D.; Garrison-Kimmel, Shea; Hopkins, Philip F.; Kereš, Dušan

    2015-10-01

    We present Feedback in Realistic Environment (FIRE)/GIZMO hydrodynamic zoom-in simulations of isolated dark matter haloes, two each at the mass of classical dwarf galaxies (Mvir ≃ 1010 M⊙) and ultra-faint galaxies (Mvir ≃ 109 M⊙), and with two feedback implementations. The resulting central galaxies lie on an extrapolated abundance matching relation from M⋆ ≃ 106 to 104 M⊙ without a break. Every host is filled with subhaloes, many of which form stars. Each of our dwarfs with M⋆ ≃ 106 M⊙ has 1-2 well-resolved satellites with M⋆ = 3-200 × 103 M⊙. Even our isolated ultra-faint galaxies have star-forming subhaloes. If this is representative, dwarf galaxies throughout the Universe should commonly host tiny satellite galaxies of their own. We combine our results with the Exploring the Local Volume in Simulations (ELVIS) simulations to show that targeting ˜ 50 kpc regions around nearby isolated dwarfs could increase the chances of discovering ultra-faint galaxies by ˜35 per cent compared to random pointings, and specifically identify the region around the Phoenix dwarf galaxy as a good potential target. The well-resolved ultra-faint galaxies in our simulations (M⋆ ≃ 3-30 × 103 M⊙) form within Mpeak ≃ 0.5-3 × 109 M⊙ haloes. Each has a uniformly ancient stellar population ( > 10 Gyr) owing to reionization-related quenching. More massive systems, in contrast, all have late-time star formation. Our results suggest that Mhalo ≃ 5 × 109 M⊙ is a probable dividing line between haloes hosting reionization `fossils' and those hosting dwarfs that can continue to form stars in isolation after reionization.

  8. A possible WISE blazar counterpart of the faint INTEGRAL active galactic nucleus IGR J02341+0228

    NASA Astrophysics Data System (ADS)

    Massaro, F.; Paggi, A.; D'Abrusco, R.

    2012-05-01

    Following the Swift-XRT identification of the counterpart for the faint INTEGRAL active galactic nucleus IGR J02341+0228, associated with a new extragalactic source: QSO B0231+022 (ATEL #4102), we searched in the Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010 AJ, 140, 1868) catalog at the position of the QSO B0231+022 source for an infrared counterpart.

  9. Red hot chili pepper. A new Calluella stoliczka, 1872 (Lissamphibia: Anura: Microhylidae) from Sarawak, East Malaysia (Borneo).

    PubMed

    Das, Indraneil; Min, Pui Yong; Hsu, Wayne W; Hertwig, Stefan T; Haas, Alexander

    2014-01-01

    A new brightly-coloured (olive and red) species of microhylid frog of the genus Calluella Stoliczka 1872 is described from the upper elevations of Gunung Penrissen and the Matang Range, Sarawak, East Malaysia (Borneo). Calluella capsa, new species, is diagnosable in showing the following combination of characters: SVL up to 36.0 mm; dorsum weakly granular; a faint dermal fold across forehead; toe tips obtuse; webbing on toes basal; lateral fringes on toes present; outer metatarsal tubercle present; and dorsum greyish-olive, with red spots; half of venter bright red, the rest with large white and dark areas. The new species is the eighth species of Calluella to be described, and the fourth known from Borneo. A preliminary phylogeny of Calluella and its relatives is presented, and the new taxon compared with congeners from Malaysia and other parts of south-east Asia.  PMID:24872245

  10. TODCOR: A New Two-Dimensional Correlation Technique to Analyze Stellar Spectra in Search for Faint Companions

    NASA Astrophysics Data System (ADS)

    Mazeh, T.; Zucker, S.; Smith, H.

    1993-12-01

    TODCOR is a new TwO-Dimensional CORrelation technique to measure radial velocities of two components of a spectroscopic binary (Zucker and Mazeh 1993, ApJ, in press). Assuming the spectra of the two components are known, the technique correlates an observed binary spectrum against a combination of the two spectra with different shifts. TODCOR measures simultaneously the radial velocities of the two stars by finding the maximum correlation. A few real single-line spectroscopic binaries already have been turned into double-line systems with TODCOR, demonstrating the power of the technique. One of the advantages of TODCOR is its ability to detect a very faint companion in a combined spectrum, and to measure its radial velocity. We present numerical tests in which we applied TODCOR to simulated spectra which were prepared as combinations of two observed infrared spectra with various luminosity ratios, together with random noise. These tests show that TODCOR can detect in principle a very faint secondary spectrum and measure correctly its velocity, provided the combined spectrum has adequate spectral coverage and S/N. Measuring the radial velocity of the faint secondary will enable us to estimate its mass, making the technique a very useful tool in the search for brown dwarfs and giant planets around nearby stars.

  11. Clover, Red (Trifolium pretense)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic modification of plants by the insertion of transgenes can be a powerful experimental approach to answer basic questions about gene product function. This technology can also be used to make improved crop varieties for use in the field. To apply this powerful tool to red clover, an important ...

  12. 'Valley Red' Strawberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Valley Red' is a new June-bearing (short-day) strawberry (Fragaria ×ananassa Duchesne ex Rozier) cultivar from the U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) breeding program in Corvallis, Ore., released in cooperation with the Oregon Agricultural Experiment Station, Th...

  13. 'Vintage' Red Raspberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Vintage' is a new primocane-fruiting red raspberry (Rubus idaeus L.) from the U.S. Dept. of Agriculture–Agricultural Research Service (USDA–ARS) breeding program in Corvallis, OR released in cooperation with the Oregon State Agricultural Experiment Station and the Washington State University Agricu...

  14. Red Cross Swimming Update.

    ERIC Educational Resources Information Center

    Vlasich, Cynthia

    1989-01-01

    Six new aquatic courses, developed by the Red Cross, are described. They are: Infant and Preschool Aquatics, Longfellow's Whale Tales (classroom water safety lessons for K-Six), Basic Water Safety, Emergency Water Safety, Lifeguard Training, and Safety Training for Swim Coaches. (IAH)

  15. Red Emitting VCSEL

    NASA Astrophysics Data System (ADS)

    Jetter, Michael; Roßbach, Robert; Michler, Peter

    This chapter describes the progress in development of vertical-cavity surface-emitting lasers (VCSEL) emitting in the red spectral region around 650 nm for data transmission over polymer optical fibers (POF). First, growth issues of red VCSEL using two different material systems, namely AlGaAs and AlGaInP, are introduced. In particular, the optical and electrical state-of-the-art characteristics as low threshold currents ({≤} 1 mA) and high output powers (several mW) are presented with a special focus on emission wavelength. Also the thermal budget and heat removal in the devices are pointed out with regard to the geometry of the VCSEL. Small-signal modulation response in terms of maximum resonance frequency in dependance on temperature behavior are discussed. Applications of these devices in optical interconnects are described and digital data transmission at data rates up to 2.1 Gbit/s over step-index POF is reported. These properties make red emitting VCSEL perfectly suited for high-speed low power consuming light sources for optical data communication via POF. By introducing InP quantum dots as gain material in red emitting VCSEL nearly temperature independent record low threshold current densities of around 10 A/cm2 could be observed.

  16. 'Saanich' Red Raspberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Saanich' is a new floricane-fruiting red raspberry (Rubus idaeus) cultivar from the breeding program at the Pacific Agri-Food Research Centre (PARC) of Agriculture and Agri-Food Canada, Agassiz, British Columbia. 'Saanich', tested as BC 89-34-41, was selected from a 1989 cross of BC 82-5-161 and BC...

  17. Canadian Red Cross.

    PubMed

    Lavender, Colleen

    2008-01-01

    The Canadian Red Cross is guided by its Fundamental Principles--humanity, impartiality, neutrality, independence, voluntary service, unity, and universality--and organized in a traditional geographic hierarchical structure. Among the characteristics that have contributed to its success are a budgeting process that starts at the local level, measurement of program outcomes, and coordinated fundraising activities at the regional level. PMID:18551842

  18. THE EXTREMELY RED HOST GALAXY OF GRB 080207

    SciTech Connect

    Hunt, Leslie; Cresci, Giovanni; Palazzi, Eliana; Rossi, Andrea; Klose, Sylvio; Savaglio, Sandra; Michalowski, Michal; Pian, Elena

    2011-08-01

    We present optical, near-infrared, and Spitzer IRAC and MIPS observations of the host galaxy of the dark Swift gamma-ray burst GRB 080207. The host is faint, with extremely red optical-infrared colors (R - K = 6.3, 24 {mu}m/R-band flux {approx}1000) making it an extremely red object (ERO) and a dust-obscured galaxy (DOG). The spectral energy distribution (SED) shows the clear signature of the 1.6 {mu}m photometric 'bump', typical of evolved stellar populations. We use this bump to establish the photometric redshift z{sub phot} as 2.2{sup +0.2}{sub -0.3}, using a vast library of SED templates, including M 82. The star formation rate (SFR) inferred from the SED fitting is {approx}119 M{sub sun} yr{sup -1}, the stellar mass 3 x 10{sup 11} M{sub sun}, and A{sub V} extinction from 1 to 2 mag. The ERO and DOG nature of the host galaxy of the dark GRB 080207 may be emblematic of a distinct class of dark GRB hosts, with high SFRs, evolved and metal-rich stellar populations, and significant dust extinction within the host galaxy.

  19. Adaptive optics for high-contrast imaging of faint substellar companions

    NASA Astrophysics Data System (ADS)

    Morzinski, Katie M.

    Direct imaging of faint objects around bright stars is challenging because the primary star's diffracted light can overwhelm low-mass companions. Nevertheless, advances in adaptive optics (AO) and high-contrast imaging have revealed the first pictures of extrasolar planets. In this dissertation I employ today's high-contrast AO techniques to image brown dwarfs around stars in the nearby Hyades cluster. Furthermore, I prepare for the next generation of high-contrast AO instrumentation, by qualifying MEMS deformable mirrors for wavefront control in the Gemini Planet Imager. In Part I, I present discovery of 3 new brown dwarfs and 36 low-mass stellar companions to 85 stars in the Hyades, imaged with AO at Keck and Lick Observatories. The "locally-optimized combination of images" (LOCI) image-diversity technique filters out the primary star to reveal faint companions. This survey is complete to the hydrogen-burning limit at separations beyond 20 AU. In the complete sample, multiplicity increases as primary star mass decreases. Additionally, the brown dwarfs are at wide >150 AU separations. Finding this preference for low binding-energy systems is an unexpected result, as the Hyades is 625 Myr old and dynamically relaxed. Future work will continue to explore this trend to understand the dynamical and star formation history of the Hyades. The brown dwarfs are near interesting transition regimes for low-mass objects; therefore, characterizing their atmospheres with spectrophotometry will serve as an important benchmark for our understanding of these cool objects. In Part II, I demonstrate micro-electro-mechanical systems (MEMS) deformable mirrors for high-order wavefront control in the Gemini Planet Imager (GPI). MEMS micromirrors have thousands of degrees of freedom and represent a significant cost efficiency over conventional glass deformable mirrors, making them ideal for high-contrast AO. In Chapter 7, I present experimental evidence that MEMS actuators function well

  20. The Chandra Deep Field North Survey. XV. Optically Bright, X-Ray-Faint Sources

    NASA Astrophysics Data System (ADS)

    Hornschemeier, A. E.; Bauer, F. E.; Alexander, D. M.; Brandt, W. N.; Sargent, W. L. W.; Bautz, M. W.; Conselice, C.; Garmire, G. P.; Schneider, D. P.; Wilson, G.

    2003-08-01

    We have analyzed optically bright, X-ray-faint [OBXF; i.e., log(fX/fR)<~-2] sources identified in an 178.9 arcmin2 area having high exposure (greater than 1500 ks) within the Chandra Deep Field North 2 Ms survey. We find 43 OBXF sources in this area, making up ~15% of the X-ray sources above a 0.5-2 keV flux of ~2.3×10-17 ergs cm-2 s-1. We present spectroscopic identifications for 42 of the OBXF sources and optical spectra for 25, including five previously unpublished redshifts. Deep optical imaging data (either Hubble Space Telescope [HST] or ground-based) are presented for all the OBXF sources; we measure the optical morphologies of the 20 galaxies having HST imaging data. The OBXF population consists mainly of normal and starburst galaxies detected out to cosmologically significant distances (i.e., to a median redshift of z=0.297 and a full redshift range z=0.06-0.845). This is notable since these distances equate to look-back times of up to ~8 Gyr; we are thus provided with a window on the X-ray emission from galaxies at redshifts much closer to the cosmic star formation peak than was possible prior to the Chandra X-Ray Observatory. The X-ray luminosity distribution of OBXF sources extends to higher luminosity than does that of ``normal'' galaxies, indicating that a significant fraction are likely dominated by low-luminosity active galactic nuclei or vigorous star formation. The lowest redshift galaxies (z~0.06-0.2) have very low X-ray-to-optical flux ratios [i.e., log(fX/fR)<~-3], which are consistent with those of normal galaxies in the local universe. By combining the detected X-ray counts, we find the average OBXF X-ray spectrum to be consistent with a Γ~2.0 power law. The 0.5-2 keV logN-logS for the OBXF galaxies is much steeper (α~-1.7) than for the general X-ray source population. Indeed, the number of OBXF sources has doubled between the 1 and 2 Ms surveys, rising sharply in numbers at faint fluxes. The extragalactic OBXF sources are found to

  1. Stellar kinematics and metallicities in the ultra-faint dwarf galaxy Reticulum II

    SciTech Connect

    Simon, J. D.

    2015-07-23

    With this study, we present Magellan/M2FS, Very Large Telescope/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity of $62.8\\pm 0.5\\;\\mathrm{km}\\;{{\\rm{s}}}^{-1}$ and a velocity dispersion of $3.3\\pm 0.7\\;\\mathrm{km}\\;{{\\rm{s}}}^{-1}$. The mass-to-light ratio of Ret II within its half-light radius is $470\\pm 210\\ {M}_{\\odot }/{L}_{\\odot }$, demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83 $\\mathrm{km}\\ {{\\rm{s}}}^{-1}$, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3 dex in metallicity, with a dispersion of 0.28 ± 0.09 dex, and we identify several extremely metal-poor stars with ${\\rm{[Fe/H]}}\\lt -3$. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a mean metallicity of ${\\rm{[Fe/H]}}=-2.65\\pm 0.07$, Ret II matches Segue 1 as the most metal-poor galaxy known. Although Ret II is the third-closest dwarf galaxy to the Milky Way, the line-of-sight integral of the dark matter density squared is ${\\mathrm{log}}_{10}(J)=18.8\\pm 0.6\\;\\;\\mathrm{GeV}{\\;}^{2}\\;{\\mathrm{cm}}^{-5}\\;$ within 0fdg2, indicating that the predicted gamma-ray flux from dark matter annihilation in Ret II is lower than that of several other dwarf galaxies.

  2. Stellar Kinematics and Metallicities in the Ultra-faint Dwarf Galaxy Reticulum II

    NASA Astrophysics Data System (ADS)

    Simon, J. D.; Drlica-Wagner, A.; Li, T. S.; Nord, B.; Geha, M.; Bechtol, K.; Balbinot, E.; Buckley-Geer, E.; Lin, H.; Marshall, J.; Santiago, B.; Strigari, L.; Wang, M.; Wechsler, R. H.; Yanny, B.; Abbott, T.; Bauer, A. H.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; D'Andrea, C. B.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dodelson, S.; Cunha, C. E.; Estrada, J.; Evrard, A. E.; Fausti Neto, A.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J.; Gaztanaga, E.; Gerdes, D.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; March, M.; Martini, P.; Miller, C. J.; Miquel, R.; Ogando, R.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Schubnell, M.; Sevilla, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Tucker, D.; Vikram, V.; Walker, A. R.; Wester, W.; DES Collaboration

    2015-07-01

    We present Magellan/M2FS, Very Large Telescope/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity of 62.8+/- 0.5 {km} {{{s}}}-1 and a velocity dispersion of 3.3+/- 0.7 {km} {{{s}}}-1. The mass-to-light ratio of Ret II within its half-light radius is 470+/- 210 {M}⊙ /{L}⊙ , demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83 {km} {{{s}}}-1, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3 dex in metallicity, with a dispersion of 0.28 ± 0.09 dex, and we identify several extremely metal-poor stars with {{[Fe/H]}}\\lt -3. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a mean metallicity of {{[Fe/H]}}=-2.65+/- 0.07, Ret II matches Segue 1 as the most metal-poor galaxy known. Although Ret II is the third-closest dwarf galaxy to the Milky Way, the line-of-sight integral of the dark matter density squared is {{log}}10(J)=18.8+/- 0.6 {GeV}{ }2 {{cm}}-5 within 0.°2, indicating that the predicted gamma-ray flux from dark matter annihilation in Ret II is lower than that of several other dwarf galaxies. Based on data obtained from the ESO Science Archive Facility under request number 157689.

  3. FAINT POPULATION III SUPERNOVAE AS THE ORIGIN OF THE MOST IRON-POOR STARS

    SciTech Connect

    Ishigaki, Miho N.; Tominaga, Nozomu; Kobayashi, Chiaki; Nomoto, Ken'ichi

    2014-09-10

    The most iron-poor stars in the Milky Way provide important observational clues to the astrophysical objects that enriched the primordial gas with heavy elements. Among them, the recently discovered iron-deficient star SMSS J031300.36–670839.3 shows a remarkable chemical composition with a non-detection of iron ([Fe/H] <–7.1) and large enhancement of carbon and magnesium relative to calcium. We investigate supernova yields of metal-free (Population III) stars to interpret the abundance pattern observed in this star. We report that the high [C/Ca] and [C/Mg] ratios and upper limits of other elemental abundances are well reproduced with the yields of core-collapse supernovae (which have normal kinetic energies of explosion E of E {sub 51} = E/10{sup 51} erg =1) and hypernovae (E {sub 51} ≥ 10) of Population III 25 M {sub ☉} or 40 M {sub ☉} stars. The best-fit models assume that the explosions undergo extensive matter mixing and fallback, leaving behind a black hole remnant. In these models, Ca is produced by static/explosive O burning and incomplete Si burning in the Population III supernova/hypernova, in contrast to the suggestion that Ca is originated from the hot-CNO cycle during pre-supernova evolution. Chemical abundances of four carbon-rich iron-poor stars with [Fe/H] <–4.5, including SMSS J031300.36–670839.3, are consistently explained by faint supernova models with ejected masses of {sup 56}Ni less than 10{sup –3} M {sub ☉}.

  4. Establishing a Network of faint DA white dwarfs as Spectrophotometric Standards

    NASA Astrophysics Data System (ADS)

    Saha, Abhijit; Narayan, Gautham; Holberg, Jay; Matheson, Thomas; Olszewski, Edward; Stubbs, Christopher; Bohlin, Ralph; Sabbi, Elena; Deustua, Susana; Rest, Armin; Axelrod, Tim; MacKenty, John W.; Camarota, Larry; Gilliland, Ron

    2015-08-01

    Systematic uncertainties in photometric calibration are the dominant source of error in current type Ia supernova dark energy studies, as well as other forefront cosmology efforts, e.g. photo-redshift determinations for weak lensing mass tomography. Current and next-generation ground-based all-sky surveys require a network of calibration stars with 1) known SEDs (to properly and unambiguously take into account filter differences), and 2) that are on a common photometric zeropoint scale across the sky to sub-percent accuracy. We are using a combination of HST panchromatic photometry and ground based spectroscopy to establish such an essential network of faint primary photometric standards, exploiting the well-understood spectral energy distributions of DA white dwarf stars that are free from the complications of observing through the Earth's time-variable atmosphere. The Balmer features in the spectra are used to deduce the two parameters (temperature and log(g)) from which we model the spectral energy distribution (SED) from these stars which have pure hydrogen atmospheres. By comparing against panchromatic broadband HST photometry, and allowing for an achromatic zero-point adjustment and mild scaling of the interstellar reddening, we find that model prediction and observation agree to a few milli-mag. By combining the zero-point and reddening adjustments with the modeled SED, for each star we obtain the incident SED above the terrestrial atmosphere, thus establishing these objects as spectrophotometric standards. We are pursuing 23 objects between 16 and 19 mag spread over the sky uniformly around the equator and northern mid-latitudes, with plans to extend this to southern latitudes. This precision photometric heritage from HST will benefit essentially all existing and upcoming survey projects, and in prticular, directly addresses one of the current barriers to understanding the nature of dark energy.

  5. Detection of a Faint Fast-moving Near-Earth Asteroid Using the Synthetic Tracking Technique

    NASA Astrophysics Data System (ADS)

    Zhai, Chengxing; Shao, Michael; Nemati, Bijan; Werne, Thomas; Zhou, Hanying; Turyshev, Slava G.; Sandhu, Jagmit; Hallinan, Gregg; Harding, Leon K.

    2014-09-01

    We report a detection of a faint near-Earth asteroid (NEA) using our synthetic tracking technique and the CHIMERA instrument on the Palomar 200 inch telescope. With an apparent magnitude of 23 (H = 29, assuming detection at 20 lunar distances), the asteroid was moving at 6.°32 day-1 and was detected at a signal-to-noise ratio (S/N) of 15 using 30 s of data taken at a 16.7 Hz frame rate. The detection was confirmed by a second observation 77 minutes later at the same S/N. Because of its high proper motion, the NEA moved 7 arcsec over the 30 s of observation. Synthetic tracking avoided image degradation due to trailing loss that affects conventional techniques relying on 30 s exposures; the trailing loss would have degraded the surface brightness of the NEA image on the CCD down to an approximate magnitude of 25 making the object undetectable. This detection was a result of our 12 hr blind search conducted on the Palomar 200 inch telescope over two nights, scanning twice over six (5.°3 × 0.°046) fields. Detecting only one asteroid is consistent with Harris's estimates for the distribution of the asteroid population, which was used to predict a detection of 1.2 NEAs in the H-magnitude range 28-31 for the two nights. The experimental design, data analysis methods, and algorithms are presented. We also demonstrate milliarcsecond-level astrometry using observations of two known bright asteroids on the same system with synthetic tracking. We conclude by discussing strategies for scheduling observations to detect and characterize small and fast-moving NEAs using the new technique.

  6. Detection of a faint fast-moving near-Earth asteroid using the synthetic tracking technique

    SciTech Connect

    Zhai, Chengxing; Shao, Michael; Nemati, Bijan; Werne, Thomas; Zhou, Hanying; Turyshev, Slava G.; Sandhu, Jagmit; Hallinan, Gregg; Harding, Leon K.

    2014-09-01

    We report a detection of a faint near-Earth asteroid (NEA) using our synthetic tracking technique and the CHIMERA instrument on the Palomar 200 inch telescope. With an apparent magnitude of 23 (H = 29, assuming detection at 20 lunar distances), the asteroid was moving at 6.°32 day{sup –1} and was detected at a signal-to-noise ratio (S/N) of 15 using 30 s of data taken at a 16.7 Hz frame rate. The detection was confirmed by a second observation 77 minutes later at the same S/N. Because of its high proper motion, the NEA moved 7 arcsec over the 30 s of observation. Synthetic tracking avoided image degradation due to trailing loss that affects conventional techniques relying on 30 s exposures; the trailing loss would have degraded the surface brightness of the NEA image on the CCD down to an approximate magnitude of 25 making the object undetectable. This detection was a result of our 12 hr blind search conducted on the Palomar 200 inch telescope over two nights, scanning twice over six (5.°3 × 0.°046) fields. Detecting only one asteroid is consistent with Harris's estimates for the distribution of the asteroid population, which was used to predict a detection of 1.2 NEAs in the H-magnitude range 28-31 for the two nights. The experimental design, data analysis methods, and algorithms are presented. We also demonstrate milliarcsecond-level astrometry using observations of two known bright asteroids on the same system with synthetic tracking. We conclude by discussing strategies for scheduling observations to detect and characterize small and fast-moving NEAs using the new technique.

  7. Evolution of faint radio sources in the VIDEO-XMM3 field

    NASA Astrophysics Data System (ADS)

    McAlpine, K.; Jarvis, M. J.; Bonfield, D. G.

    2013-12-01

    It has been speculated that low-luminosity radio-loud active galactic nuclei (AGN) have the potential to serve as an important source of AGN feedback, and may be responsible for suppressing star formation activity in massive elliptical galaxies at late times. As such the cosmic evolution of these sources is vitally important to understand the significance of such AGN feedback processes and their influence on the global star formation history of the Universe. In this paper, we present a new investigation of the evolution of faint radio sources out to z ˜ 2.5. We combine a 1 square degree Very Large Array radio survey, complete to a depth of 100 μJy, with accurate 10 band photometric redshifts from the following surveys: Visible and Infrared Survey Telescope for Astronomy Deep Extragalactic Observations and Canada-France-Hawaii Telescope Legacy Survey. The results indicate that the radio population experiences mild positive evolution out to z ˜ 1.2 increasing their space density by a factor of ˜3, consistent with results of several previous studies. Beyond z = 1.2, there is evidence of a slowing down of this evolution. Star-forming galaxies drive the more rapid evolution at low redshifts, z < 1.2, while more slowly evolving AGN populations dominate at higher redshifts resulting in a decline in the evolution of the radio luminosity function at z > 1.2. The evolution is best fitted by pure luminosity evolution with star-forming galaxies evolving as (1 + z)2.47 ± 0.12 and AGN as (1 + z)1.18 ± 0.21.

  8. A Deeper Look at Faint Hα Emission in Nearby Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Lee, Janice C.; Veilleux, Sylvain; McDonald, Michael; Hilbert, Bryan

    2016-02-01

    We present deep Hα imaging of three nearby dwarf galaxies, carefully selected to optimize observations with the Maryland-Magellan Tunable Filter (MMTF) on the Magellan 6.5 m telescope. An effective bandpass of ˜13 Å is used, and the images reach 3σ flux limits of ˜8 × 10-18 erg s-1 cm-2, which is about an order of magnitude lower than standard narrowband observations obtained by the most recent generation of local Hα galaxy surveys. The observations were originally motivated by the finding that the Hα/FUV flux ratio of galaxies systematically declines as global galactic properties such as the star formation rate (SFR) and stellar mass decrease. The three dwarf galaxies selected for study have SFRs that, when calculated from their Hα luminosities using standard conversion recipes, are ˜50% of those based on the FUV. Follow-up studies of many of the potential causes for the trends in the Hα/FUV flux ratio have been performed, but the possibility that previous observations have missed a non-negligible fraction of faint ionized emission in dwarf galaxies has not been investigated. The MMTF observations reveal both diffuse and structured Hα emission (filaments, shells, possible single-star H ii regions) spanning extents up to 2.5 times larger relative to previous observations. However, only up to an additional ˜5% of Hα flux is captured, which does not account for the trends in the Hα/FUV ratio. Beyond investigation of the Hα/FUV ratio, the impact of the newly detected extended flux on our understanding of star formation, the properties of H ii regions, and the propagation of ionizing photons warrant further investigation.

  9. GHOSTS I: A new faint very isolated dwarf galaxy at D = 12 ± 2 Mpc

    SciTech Connect

    Monachesi, Antonela; Bell, Eric F.; Radburn-Smith, David J.; Dalcanton, Julianne J.; De Jong, Roelof S.; Streich, David; Vlajić, Marija; Bailin, Jeremy; Holwerda, Benne W.; Alyson Ford, H.; Zucker, Daniel B.

    2014-01-10

    We report the discovery of a new faint dwarf galaxy, GHOSTS I, using HST/ACS data from one of our GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disk, and Star clusters) fields. Its detected individual stars populate an approximately 1 mag range of its luminosity function (LF). Using synthetic color-magnitude diagrams (CMDs) to compare with the galaxy's CMD, we find that the colors and magnitudes of GHOSTS I's individual stars are most consistent with being young helium-burning and asymptotic giant branch stars at a distance of ∼12 ± 2 Mpc. Morphologically, GHOSTS I appears to be actively forming stars, so we tentatively classify it as a dwarf irregular (dIrr) galaxy, although future Hubble Space Telescope (HST) observations deep enough to resolve a larger magnitude range in its LF are required to make a more secure classification. GHOSTS I's absolute magnitude is M{sub V}∼−9.85{sub −0.33}{sup +0.40}, making it one of the least luminous dIrr galaxies known, and its metallicity is lower than [Fe/H] = –1.5 dex. The half-light radius of GHOSTS I is 226 ± 38 pc and its ellipticity is 0.47 ± 0.07, similar to Milky Way and M31 dwarf satellites at comparable luminosity. There are no luminous massive galaxies or galaxy clusters within ∼4 Mpc from GHOSTS I that could be considered as its host, making it a very isolated dwarf galaxy in the local universe.

  10. DISCOVERY AND CHARACTERIZATION OF A FAINT STELLAR COMPANION TO THE A3V STAR zeta VIRGINIS

    SciTech Connect

    Hinkley, Sasha; Hillenbrand, Lynne; Oppenheimer, Ben R.; Brenner, Douglas; Zimmerman, Neil; Sivaramakrishnan, Anand; Roberts, Lewis C.; Roberts, Jennifer E.; Burruss, Rick; Shao, Michael; Vasisht, Gautam; Parry, Ian R.; King, David L.; Soummer, Remi; Simon, Michal; Perrin, Marshall D.; Lloyd, James P.; Bouchez, Antonin; Dekany, Richard; Beichman, Charles

    2010-03-20

    Through the combination of high-order adaptive optics and coronagraphy, we report the discovery of a faint stellar companion to the A3V star zeta Virginis. This companion is {approx}7 mag fainter than its host star in the H band, and infrared imaging spanning 4.75 years over five epochs indicates this companion has common proper motion with its host star. Using evolutionary models, we estimate its mass to be 0.168{sup +0.012}{sub -0.016} M{sub sun}, giving a mass ratio for this system q = 0.082{sup +0.007}{sub -0.008}. Assuming the two objects are coeval, this mass suggests an M4V-M7V spectral type for the companion, which is confirmed through {integral} field spectroscopic measurements. We see clear evidence for orbital motion from this companion and are able to constrain the semimajor axis to be {approx}>24.9 AU, the period {approx}>124 yr, and eccentricity {approx}>0.16. Multiplicity studies of higher mass stars are relatively rare, and binary companions such as this one at the extreme low end of the mass ratio distribution are useful additions to surveys incomplete at such a low mass ratio. Moreover, the frequency of binary companions can help to discriminate between binary formation scenarios that predict an abundance of low-mass companions forming from the early fragmentation of a massive circumstellar disk. A system such as this may provide insight into the anomalous X-ray emission from A stars, hypothesized to be from unseen late-type stellar companions. Indeed, we calculate that the presence of this M-dwarf companion easily accounts for the X-ray emission from this star detected by ROSAT.

  11. The faint young Sun problem revisited with a 3-D climate-carbon model - Part 1

    NASA Astrophysics Data System (ADS)

    Le Hir, G.; Teitler, Y.; Fluteau, F.; Donnadieu, Y.; Philippot, P.

    2014-04-01

    During the Archaean, the Sun's luminosity was 18 to 25% lower than the present day. One-dimensional radiative convective models (RCM) generally infer that high concentrations of greenhouse gases (CO2, CH4) are required to prevent the early Earth's surface temperature from dropping below the freezing point of liquid water and satisfying the faint young Sun paradox (FYSP, an Earth temperature at least as warm as today). Using a one-dimensional (1-D) model, it was proposed in 2010 that the association of a reduced albedo and less reflective clouds may have been responsible for the maintenance of a warm climate during the Archaean without requiring high concentrations of atmospheric CO2 (pCO2). More recently, 3-D climate simulations have been performed using atmospheric general circulation models (AGCM) and Earth system models of intermediate complexity (EMIC). These studies were able to solve the FYSP through a large range of carbon dioxide concentrations, from 0.6 bar with an EMIC to several millibars with AGCMs. To better understand this wide range in pCO2, we investigated the early Earth climate using an atmospheric GCM coupled to a slab ocean. Our simulations include the ice-albedo feedback and specific Archaean climatic factors such as a faster Earth rotation rate, high atmospheric concentrations of CO2 and/or CH4, a reduced continental surface, a saltier ocean, and different cloudiness. We estimated full glaciation thresholds for the early Archaean and quantified positive radiative forcing required to solve the FYSP. We also demonstrated why RCM and EMIC tend to overestimate greenhouse gas concentrations required to avoid full glaciations or solve the FYSP. Carbon cycle-climate interplays and conditions for sustaining pCO2 will be discussed in a companion paper.

  12. Exploring the spectral properties of faint hard X-ray sources with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Piconcelli, E.; Cappi, M.; Bassani, L.; Fiore, F.; Di Cocco, G.; Stephen, J. B.

    2002-11-01

    We present a spectroscopic study of 41 hard X-ray sources detected serendipitously with high significance (>5sigma in the 2-10 keV band) in seven EPIC performance/verification phase observations. The large collecting area of EPIC allows us to explore the spectral properties of these faint hard X-ray sources with 2 < F2-10 < 80 x 10-14 erg cm-2 s-1 even though the length of the exposures are modest ( ~ 20 ks). Optical identifications are available for 21 sources of our sample. Using a simple power law plus Galactic absorption model we find an average value of the photon index Gamma ~ 1.6-1.7, broadly consistent with recent measurements made at similar fluxes with ASCA and with Chandra stacked spectral analyses. We find that 31 out of 41 sources are well fitted by this simple model and only eight sources require absorption in excess of the Galactic value. Interestingly enough, one third of these absorbed sources are broad line objects, though with moderate column densities. Two sources in the sample are X-ray bright optically quiet galaxies and show flat X-ray spectra. Comparing our observational results with those expected from standard synthesis models of the cosmic X-ray background (CXB) we find a fraction of unabsorbed to absorbed sources larger than predicted by theoretical models at our completeness limit of F2-10 ~ 5 x 10-14 erg cm-2 s-1. The results presented here illustrate well how wide-angle surveys performed with EPIC on board XMM-Newton allow population studies of interesting and unusual sources to be made as well as enabling constraints to be placed on some input parameters for synthesis models of the CXB.

  13. DISCOVERY OF A FAINT COMPANION TO ALCOR USING MMT/AO 5 {mu}m IMAGING

    SciTech Connect

    Mamajek, Eric E.; Kenworthy, Matthew A.; Hinz, Philip M.; Meyer, Michael R.

    2010-03-15

    We report the detection of a faint stellar companion to the famous nearby A5V star Alcor (80 UMa). The companion has M-band ({lambda} = 4.8 {mu}m) magnitude 8.8 and projected separation 1.''11 (28 AU) from Alcor. The companion is most likely a low-mass ({approx}0.3 M {sub sun}) active star which is responsible for Alcor's X-ray emission detected by ROSAT (L {sub X} {approx_equal} 10{sup 28.3} erg s{sup -1}). Alcor is a nuclear member of the Ursa Major star cluster (UMa; d {approx_equal} 25 pc, age {approx_equal} 0.5 Gyr), and has been occasionally mentioned as a possible distant (709'') companion of the stellar quadruple Mizar ({zeta} UMa). Comparing the revised Hipparcos proper motion for Alcor with the mean motion for other UMa nuclear members shows that Alcor has a peculiar velocity of 1.1 km s{sup -1}, which is comparable to the predicted velocity amplitude induced by the newly discovered companion ({approx}1 km s{sup -1}). Using a precise dynamical parallax for Mizar and the revised Hipparcos parallax for Alcor, we find that Mizar and Alcor are physically separated by 0.36 {+-} 0.19 pc (74 {+-} 39 kAU; minimum 18 kAU), and their velocity vectors are marginally consistent ({chi}{sup 2} probability 6%). Given their close proximity and concordant motions we suggest that the Mizar quadruple and the Alcor binary be together considered the second closest stellar sextuplet. The addition of Mizar-Alcor to the census of stellar multiples with six or more components effectively doubles the local density of such systems within the local volume (d < 40 pc)

  14. THE INFLUENCE OF RED SPIRAL GALAXIES ON THE SHAPE OF THE LOCAL K-BAND LUMINOSITY FUNCTION

    SciTech Connect

    Bonne, Nicolas J.; Brown, Michael J. I.; Jones, Heath; Pimbblet, Kevin A.

    2015-02-01

    We have determined K-band luminosity functions for 13,325 local universe galaxies as a function of morphology and color (for K {sub tot} ≤ 10.75). Our sample is drawn from the Two Micron All Sky Survey Extended Source Catalog, with all sample galaxies having measured morphologies and distances (including 4219 archival redshift-independent distances). The luminosity function for our total sample is in good agreement with previous works, but is relatively smooth at faint magnitudes (due to bulk flow distance corrections). We investigated the differences due to morphological and color selection using 5417 sample galaxies with NASA Sloan Atlas optical colors and find that red spirals comprise 20%-50% of all spirals with –25 ≤ M{sub K}  < –20. Fainter than M{sub K} = –24, red spirals are as common as early types, explaining the different faint end slopes (α = –0.87 and –1.00 for red and early-types, respectively). While we find red spirals comprise more than 50% of all M{sub K}  < –25 spiral galaxies, they do not dominate the bright end of the overall red galaxy luminosity function, which is dominated by early-type galaxies. The brightest red spirals have ongoing star formation and those without are frequently misclassified as early-types. The faintest ones have an appearance and Sérsic indices consistent with faded disks, rather than true bulge-dominated galaxies.

  15. Registration of 'Red Ruby' Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red Ruby’ soft red winter wheat (Triticum aestivum L.) was developed by the Michigan Agricultural Experiment Station and released in 2007 via an exclusive licensing agreement through Michigan State University (MSU) Technologies. Red Ruby was selected from the cross Pioneer ‘2552’/Pioneer ‘2737W’ ma...

  16. Construction and characterization of a red-emitting luciferase

    NASA Astrophysics Data System (ADS)

    Eames, Brian F.; Benaron, David A.; Stevenson, David K.; Contag, Christopher H.

    1999-07-01

    Red light is transmitted through live tissue more efficiently than other wavelengths of visible light, thus by red-shifting the emission of bioluminescent reporters, we may enhance their utility for in vivo monitoring of biological processes. Codon changes at positions that may shift the yellow-green emission to red, based on studies of a related luciferase, were introduced into a variant of the North American firefly luciferase. Clones containing the desired mutation were selected based on the introduction of unique restriction enzyme sites and transfected into NIH 3T3 cells. Expression levels were evaluated using an intensified charge coupled device camera. Upon spectral analysis, all mutant luciferases demonstrated red-orange emission. Two emission peaks were detected in each spectrum, each clone with different peak heights at 560 nm and 610 nm. Sequence analyses of the compete coding region of several clones confirmed the presence of the target mutations, although sequence variation was observed at several secondary sites, likely resulting from the infidelity of Taq polymerase used in the mutagenesis protocol. A clone that demonstrated a strong 610 nm peak with a minimum shoulder at 560 nm was selected for use in animals. In summary, a red-shifted mutant of a well-characterized luciferase reporter gene was generated. Red light from this enzyme may both penetrate mammalian tissues to a greater extent and provide a tool for multicolor biological assays.

  17. Red-Hot Saturn

    NASA Technical Reports Server (NTRS)

    2005-01-01

    These side-by-side false-color images show Saturn's heat emission. The data were taken on Feb. 4, 2004, from the W. M. Keck I Observatory, Mauna Kea, Hawaii. Both images were taken with infrared radiation. The image on the left was taken at a wavelength near 17.65 microns and is sensitive to temperatures in Saturn's upper troposphere. The image on the right was taken at a wavelength of 8 microns and is sensitive to temperatures in Saturn's stratosphere. The prominent hot spot at the bottom of each image is at Saturn's south pole. The warming of the southern hemisphere was expected, as Saturn was just past southern summer solstice, but the abrupt changes in temperature with latitude were not expected.

    The troposphere temperature increases toward the pole abruptly near 70 degrees latitude from 88 to 89 Kelvin (-301 to -299 degrees Fahrenheit) and then to 91 Kelvin (-296 degrees Fahrenheit) right at the pole. Near 70 degrees latitude, the stratospheric temperature increases even more abruptly from 146 to 150 Kelvin (-197 to -189 degrees Fahrenheit) and then again to 151 Kelvin (-188 degrees Fahrenheit) right at the pole.

    While the rings are too faint to be detected at 8 microns (right), they show up at 17.65 microns. The ring particles are orbiting Saturn to the left on the bottom and to the right on the top. The lower left ring is colder than the lower right ring, because the particles are just moving out of Saturn's shadow where they have cooled off. As they orbit Saturn, they warm up to a maximum just before passing behind Saturn again in shadow.

  18. A DOUBLE MAIN SEQUENCE IN THE GLOBULAR CLUSTER NGC 6397

    SciTech Connect

    Milone, A. P.; Aparicio, A.; Marino, A. F.; Piotto, G.; Bedin, L. R.; Anderson, J.; Cassisi, S.; Rich, R. M. E-mail: aparicio@iac.es E-mail: giampaolo.piotto@unipd.it E-mail: bedin@stsci.edu E-mail: rmr@astro.ucla.edu

    2012-01-20

    High-precision multi-band Hubble Space Telescope (HST) photometry reveals that the main sequence of the globular cluster NGC 6397 splits into two components, containing {approx}30% and {approx}70% of the stars. This double sequence is consistent with the idea that the cluster hosts two stellar populations: (1) a primordial population that has a composition similar to field stars, containing {approx}30% of the stars, and (2) a second generation with enhanced sodium and nitrogen, depleted carbon and oxygen, and a slightly enhanced helium abundance ({Delta}Y {approx} 0.01). We examine the color difference between the two sequences across a variety of color baselines and find that the second sequence is anomalously faint in m{sub F336W}. Theoretical isochrones indicate that this could be due to NH depletion.

  19. The great red flashlight

    NASA Astrophysics Data System (ADS)

    Halbach, Edward A.

    After fifty years of fighting with flashlights which persisted in rolling to the ground, being mislaid, or stashed in a pocket, the author designed a unit which was always on hand and needed no search for the switch. A normally closed switch, internal to the bottom of the flashlight case, is opened by the weight of the unit suspended on a cord about the neck. Lifting the unit with two fingers turns on the red light, while releasing the unit automatically turns it off. A felt covering around the flashlight provides comfort on cold nights. Because this red light would be a welcome tool for other variable star observers, more units were assembled and brought to the AAVSO meeting in Houston for distribution to observers who agreed to give each unit a workout and report on its performance. The author is waiting to hear from these observers.

  20. Great Red Spot (GRS)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    A huge permanent anticyclone in Jupiter's southern hemisphere, visible as a reddish oval at just over 20 °S. The earliest unequivocal observation was by Heinrich Schwabe in 1831 (the often-quoted sighting by Robert Hooke in 1664 now seems to have been of a similar but different spot). The GRS became a striking feature around 1880, when it developed a deep red coloration. It was also prominent in ...

  1. Red giants seismology

    NASA Astrophysics Data System (ADS)

    Mosser, B.; Samadi, R.; Belkacem, K.

    2013-11-01

    The space-borne missions CoRoT and Kepler are indiscreet. With their asteroseismic programs, they tell us what is hidden deep inside the stars. Waves excited just below the stellar surface travel throughout the stellar interior and unveil many secrets: how old is the star, how big, how massive, how fast (or slow) its core is dancing. This paper intends to paparazze the red giants according to the seismic pictures we have from their interiors.

  2. Millimagnitude Photometry for Transiting Extrasolar Planetary Candidates. IV. Solution to the Puzzle of the Extremely Red OGLE-TR-82 Primary

    NASA Astrophysics Data System (ADS)

    Hoyer, Sergio; Ramírez Alegría, Sebastián; Ivanov, Valentin D.; Minniti, Dante; Pietrzyński, Grzegorz; Ruíz, María Teresa; Gieren, Wolfgang; Udalski, Andrzej; Zoccali, Manuela; Carrasco, Eleazar Rodrigo; Díaz, Rodrigo F.; Fernández, José Miguel; Gallardo, José; Rejkuba, Marina; Pérez, Felipe

    2007-11-01

    We present precise new V-, I-, and Ks-band photometry for the planetary-transit candidate star OGLE-TR-82. V-band images acquired in good seeing with the VIMOS instrument at the Very Large Telescope allowed us to measure V=20.61+/-0.03 mag for this star despite the presence of a brighter neighbor about 1" away. This faint magnitude answers the question why it has not been possible to measure radial velocities for this object. One transit of this star has been observed with the GMOS-S instrument on Gemini South in the i and g bands, which allowed us to verify that this is not a false positive, to confirm the transit amplitude measured by OGLE, and to improve the ephemeris. The transit is better defined in the i-band light curve (with a depth of Ai=0.034 mag), than in the g band (Ag=0.1 mag), in which the star is significantly fainter. Near-IR photometry obtained with the SOFI array at the ESO New Technology Telescope yields K=12.20+/-0.10 and V-K=8.40+/-0.10, so red that it is unlike any transit candidate studied before. With the new data, we consider two possible configurations for the system: (1) a nearby M7 V star or (2) a blend with a very reddened, distant red giant. The first hypothesis would give a radius for the companion of Rp=0.3+/-0.1 RJ, i.e., the size of Neptune. Quantitative analysis of near-IR spectroscopy finally shows that OGLE-TR-82 is a distant, reddened, metal-poor early K giant, confirmed by direct comparison with stellar templates, which gives as a best match a K3 III star. Therefore, we rule out a planetary nature for the companion, and conclude that this system is a main-sequence binary blended with a background red giant. As a case study, a system that can so mimic a planetary transit presents a lesson for future transit surveys. Based on observations collected with the Gemini South telescope (queue observing, program GS-2005B-Q-9) and with the Very Large Telescope at Paranal Observatory (J. M. F. and D. M., Visiting Astronomers) and the ESO

  3. Dna Sequencing

    DOEpatents

    Tabor, Stanley; Richardson, Charles C.

    1995-04-25

    A method for sequencing a strand of DNA, including the steps off: providing the strand of DNA; annealing the strand with a primer able to hybridize to the strand to give an annealed mixture; incubating the mixture with four deoxyribonucleoside triphosphates, a DNA polymerase, and at least three deoxyribonucleoside triphosphates in different amounts, under conditions in favoring primer extension to form nucleic acid fragments complementory to the DNA to be sequenced; labelling the nucleic and fragments; separating them and determining the position of the deoxyribonucleoside triphosphates by differences in the intensity of the labels, thereby to determine the DNA sequence.

  4. Mantle flow beneath Arabia offset from the opening Red Sea

    NASA Astrophysics Data System (ADS)

    Chang, Sung-Joon; Merino, Miguel; Van der Lee, Suzan; Stein, Seth; Stein, Carol A.

    2011-02-01

    Continental rifting involves a poorly understood sequence of lithospheric stretching, volcanism, and mantle flow that evolves to seafloor spreading. We present new insight from inversion of seismic traveltimes and waveforms beneath Arabia and surroundings. Low velocities occur beneath the southern Red Sea and Gulf of Aden, consistent with active spreading. However, hot material extends not below the northern Red Sea, but is offset eastward beneath Arabia, showing mantle flow from the Afar hotspot. The location of this channel beneath volcanic rocks erupted since rifting began 30 million years ago indicates that flow moves with Arabia. We propose that the absence of seafloor spreading in the northern Red Sea reflects the offset flow. This geometry may evolve to spreading in the Northern Red Sea, rifting of Arabia, or both. This situation has aspects of both active and passive rifting, showing that both can occur before coalescing to seafloor spreading.

  5. Stellar kinematics and metallicities in the ultra-faint dwarf galaxy Reticulum II

    DOE PAGESBeta

    Simon, J. D.

    2015-07-23

    With this study, we present Magellan/M2FS, Very Large Telescope/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity ofmore » $$62.8\\pm 0.5\\;\\mathrm{km}\\;{{\\rm{s}}}^{-1}$$ and a velocity dispersion of $$3.3\\pm 0.7\\;\\mathrm{km}\\;{{\\rm{s}}}^{-1}$$. The mass-to-light ratio of Ret II within its half-light radius is $$470\\pm 210\\ {M}_{\\odot }/{L}_{\\odot }$$, demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83 $$\\mathrm{km}\\ {{\\rm{s}}}^{-1}$$, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3 dex in metallicity, with a dispersion of 0.28 ± 0.09 dex, and we identify several extremely metal-poor stars with $${\\rm{[Fe/H]}}\\lt -3$$. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a mean metallicity of $${\\rm{[Fe/H]}}=-2.65\\pm 0.07$$, Ret II matches Segue 1 as the most metal-poor galaxy known. Although Ret II is the third-closest dwarf galaxy to the Milky Way, the line-of-sight integral of the dark matter density squared is $${\\mathrm{log}}_{10}(J)=18.8\\pm 0.6\\;\\;\\mathrm{GeV}{\\;}^{2}\\;{\\mathrm{cm}}^{-5}\\;$$ within 0fdg2, indicating that the predicted gamma-ray flux from dark matter annihilation in Ret II is lower than that of several other dwarf galaxies.« less

  6. Constraints to the Cold Classical KBO population from HST observations of faint objects

    NASA Astrophysics Data System (ADS)

    Penteado, Paulo F.; Trilling, David; Grundy, William

    2015-11-01

    The size distribution of the known Kuiper Belt Objects has been described by a double power law, with a break at R magnitude 25. There are two leading interpretations to this break: 1) It is the result of the collisional evolution among these KBOs, with the objects smaller than the break being the population most affected by collisional erosion. 2) The size distribution break is primordial, set during the Kuiper Belt formation.The low inclination Kuiper Belt Objects, the Cold Classical population, is thought to have been dynamically isolated since the formation of the Solar System, and thus only collisions between Cold Classicals would have affected their size distribution. If the size distribution is collisional, it probes parameters of the Kuiper Belt history: strengths of the bodies, impact energies and frequency, and the the number of objects. If the distribution is primordial, it reveals parameters of the Kuiper Belt accretion, as well as limits on its subsequent collisional history.In this work, we obtained new HST observations of 5 faint Cold Classicals, which we combine with previous HST observations, to examine the distribution of two properties of the smallest KBOs: colors and binary fraction. These two properties can differentiate between a primordial and a collisional origin of the size distribution break. If the smaller bodies have been through extensive collisional evolution, they will have exposed materials from their interiors, which has not been exposed to weathering, and thus should be bluer than the old surfaces of the larger bodies. An independent constraint can be derived from the fraction of binary objects: the angular momentum of the observed binaries is typically too high to result from collisions, thus a collisionally-evolved population would have a lower binary fraction, due to the easier separation of binaries, compared to the disruption of similar-sized bodies, and the easier disruption of the binary components, due to the smaller size

  7. Investigating the early Earth faint young Sun problem with a general circulation model

    NASA Astrophysics Data System (ADS)

    Kunze, M.; Godolt, M.; Langematz, U.; Grenfell, J. L.; Hamann-Reinus, A.; Rauer, H.

    2014-08-01

    The faint young Sun problem, i.e. the contradiction of a reduced solar luminosity by 15-25% during the Archaean and the geological evidence for relatively high surface temperatures that allowed the presence of liquid water, is still mostly open. It is suggested that the cooling induced by a fainter Sun was e.g. offset by higher levels of greenhouse gases (GHGs) during the Archaean, but achieving the amounts of carbon dioxide (CO2) that are necessary to solve the problem can not be supported by proxy data and the estimates of other additional GHGs diverge. In our study we investigate this problem by using the climate model EMAC with a spectrally resolved irradiance dataset valid for the Archaean epoch of the Earth. Our experimental setup contains a series of model runs which allow the investigation of the role of the continents, the ozone and oxygen content of the atmosphere, the solar luminosity, and the CO2 concentration on the climate of the Archaean. Replacing the present day continents with a global ocean lead to a warming at the surface by ~3 K and an intensified hydrological cycle. The generation of planetary waves and their propagation to the middle atmosphere is reduced, which intensifies the polar night jet and decelerates the Brewer-Dobson circulation. Slightly lower global annual mean temperatures can be found for an anoxic atmosphere. The absent ozone heating in the middle atmosphere leads to very low temperatures in the middle atmosphere and a vanishing polar night jet, whereas the subtropical jets and the Hadley circulation are intensified. The reduction of the solar luminosity to 82% of the present value leads to a globally ice-covered planet and very dry conditions. Prescribing 10 times the present atmospheric level of CO2 with the same solar luminosity leads to a broad belt of liquid surface water throughout the year, although the global annual mean temperature is below the freezing point of water. On reducing the solar luminosity to 77% of the

  8. THE [O III] NEBULA OF THE MERGER REMNANT NGC 7252: A LIKELY FAINT IONIZATION ECHO

    SciTech Connect

    Schweizer, Francois; Kelson, Daniel D.; Villanueva, Edward V.; Seitzer, Patrick; Walth, Gregory L.

    2013-08-20

    We present images and spectra of a {approx}10 kpc-sized emission-line nebulosity discovered in the prototypical merger remnant NGC 7252 and dubbed the ''[O III] nebula'' because of its dominant [O III] {lambda}5007 line. This nebula seems to yield the first sign of episodic active galactic nucleus (AGN) activity still occurring in the remnant, {approx}220 Myr after the coalescence of two gas-rich galaxies. Its location and kinematics suggest it belongs to a stream of tidal-tail gas falling back into the remnant. Its integrated [O III] {lambda}5007 luminosity is 1.4 Multiplication-Sign 10{sup 40} erg s{sup -1}, and its spectrum features some high-excitation lines, including He II {lambda}4686. In diagnostic line-ratio diagrams, the nebula lies in the domain of Seyfert galaxies, suggesting that it is photoionized by a source with a power-law spectrum. Yet, a search for AGN activity in NGC 7252 from X-rays to radio wavelengths yields no detection, with the most stringent upper limit set by X-ray observations. The upper luminosity limit of L{sub 2-10{sub keV,0}}<5 Multiplication-Sign 10{sup 39} erg s{sup -1} estimated for the nucleus is {approx}10{sup 3} times lower than the minimum ionizing luminosity of {approx}> 5 Multiplication-Sign 10{sup 42} erg s{sup -1} necessary to excite the nebula. This large discrepancy suggests that the nebula is a faint ionization echo excited by a mildly active nucleus that has declined by {approx}3 orders of magnitude over the past 20,000-200,000 yr. In many ways this nebula resembles the prototypical ''Hanny's Voorwerp'' near IC 2497, but its size is 3 Multiplication-Sign smaller and its [O III] luminosity {approx}100 Multiplication-Sign lower. We propose that it be classified as an extended emission-line region (EELR). The [O III] nebula is then the lowest-luminosity ionization echo and EELR discovered so far, indicative of recent, probably sputtering AGN activity of Seyfert-like intensity in NGC 7252.

  9. GPU-accelerated Faint Streak Detection for Uncued Surveillance of LEO

    NASA Astrophysics Data System (ADS)

    Zimmer, P.; Ackermann, M.; McGraw, J. T.

    2013-09-01

    By astronomical standards, small objects (<10cm) in LEO illuminated by the Sun under terminator conditions are quite bright, depositing 100's to 1000's of photons per second into small telescope apertures (< 1m diameter). The challenge in discovering these objects with no a priori knowledge of their orbit (i.e. uncued surveillance) is that their relative motion with respect to a ground-based telescope makes them appear to have large angular rates of motion, up to and exceeding 1 degree per second. Thus in even a short exposure, the signal from the object is smeared out in a streak with low signal-to-noise per pixel. Go Green Termite (GGT), Inc. of Gilroy, CA, in collaboration with the University of New Mexico (UNM), is building two proof-of-concept wide-field imaging systems to test, develop and prove a novel streak detection technique. The imaging systems are built from off-the-shelf optics and detectors resulting in a 350mm aperture and a 6 square degree field of view. For streak detection, field of view is of critical importance because the maximum exposure time on the object is limited by its crossing time. In this way, wider fields of view impact surveys for LEO objects both by increasing the survey volume and increasing sensitivity. Using our newly GPU-accelerated detection scheme, the proof-of-concept systems are expected to be able to detect objects fainter than 12th magnitude moving at 1 degree per second and possibly as faint as 13th magnitude for slower moving objects. Meter-class optical systems using these techniques should be able to detect objects fainter than 14th magnitude, which is roughly equivalent to a golf ball at 1000km altitude. The goal of this work is to demonstrate a scalable system for near real time detection of fast moving objects that can be then handed off to other instruments capable of tracking and characterizing them. The two proof-of-concept systems, separated by ~30km, work together by taking simultaneous images of the same

  10. Caltech Faint Galaxy Redshift Survey. XI. The Merger Rate to Redshift 1 from Kinematic Pairs.

    PubMed

    Carlberg; Cohen; Patton; Blandford; Hogg; Yee; Morris; Lin; Hall; Sawicki; Wirth; Cowie; Hu; Songaila

    2000-03-20

    The rate of mass accumulation due to galaxy merging depends on the mass, density, and velocity distribution of galaxies in the near neighborhood of a host galaxy. The fractional luminosity in kinematic pairs combines all of these effects in a single estimator that is relatively insensitive to population evolution. Here we use a k-corrected and evolution-compensated volume-limited sample having an R-band absolute magnitude of Mk,eRFaint Galaxy Redshift Survey and 3000 from the Canadian Network for Observational Cosmology field galaxy survey to measure the rate and redshift evolution of merging. The combined sample has an approximately constant comoving number and luminosity density from redshift 0.1 to 1.1 (OmegaM=0.2, OmegaLambda=0.8); hence, any merger evolution will be dominated by correlation and velocity evolution, not density evolution. We identify kinematic pairs with projected separations less than either 50 or 100 h-1 kpc and rest-frame velocity differences of less than 1000 km s-1. The fractional luminosity in pairs is modeled as fL&parl0;Deltav,rp,Mk,er&parr0;&parl0;1+z&parr0;mL, where &sqbl0;fL,mL&sqbr0; are &sqbl0;0.14+/-0.07,0+/-1.4&sqbr0; and &sqbl0;0.37+/-0.7,0.1+/-0.5&sqbr0; for rp/=0.2M*) is 0.02+/-0.01&parl0;1+z&parr0;0.1+/-0.5M* Gyr-1. Present-day high-luminosity galaxies therefore have accreted approximately 0.15M* of their mass over the approximately 7 Gyr to redshift 1. Since merging is likely only weakly dependent on the host mass, the fractional effect, deltaM&solm0;M approximately 0.15M*&solm0;M, is dramatic for lower mass

  11. The Spectroscopic Properties of Lyα-Emitters at z ˜2.7: Escaping Gas and Photons from Faint Galaxies

    NASA Astrophysics Data System (ADS)

    Trainor, Ryan F.; Steidel, Charles C.; Strom, Allison L.; Rudie, Gwen C.

    2015-08-01

    We present a spectroscopic survey of 318 faint ({R}˜ 27, L˜ 0.1{L}*), Lyα-emission-selected galaxies (LAEs) in regions centered on the positions of hyperluminous QSOs (HLQSOs) at 2.5\\lt z\\lt 3. A sample of 32 LAEs with rest-frame optical emission line spectra from Keck/Multi-Object Spectrometer For InfraRed Exploration (MOSFIRE) are used to interpret the LAE spectra in the context of their systemic redshifts. The fields are part of the Keck Baryonic Structure Survey, which includes substantial ancillary multi-wavelength imaging from both the ground and space. From a quantitative analysis of the diverse Lyα spectral morphologies, including line widths, asymmetries, and multi-peaked profiles, we find that peak widths and separations are typically smaller than among samples of more luminous continuum-selected galaxies (Lyman-break galaxies and their analogs; LBGs) at similar redshifts. We find tentative evidence for an association between Lyα spectral morphology and external illumination by the nearby HLQSO. Using the MOSFIRE subsample, we find that the peak of the resolved (R ≈ 1300) Lyα line is shifted by +200 km s-1 with respect to systemic across a diverse set of galaxies including both LAEs and LBGs. We also find a small number of objects with significantly blueshifted Lyα emission, a potential indicator of accreting gas. The Lyα-to-Hα line ratios measured for the MOSFIRE subset suggest that the LAEs in this sample have Lyα escape fractions {f}{esc,{Ly}α } ≈ 30%, significantly higher than typical LBG samples. Using redshifts calibrated by our MOSFIRE sample, we construct composite LAE spectra, finding the first evidence for metal-enriched outflows in such intrinsically faint high-redshift galaxies. These outflows have smaller continuum covering fractions ({f}{{c}}≈ 0.3) and velocities ({v}{ave} ≈ 100-200 km s-1, {v}{max} ≈ 500 km s-1) than those associated with typical LBGs, suggesting that the gas covering fraction is a likely driver of

  12. SELFI: an object-based, Bayesian method for faint emission line source detection in MUSE deep field data cubes

    NASA Astrophysics Data System (ADS)

    Meillier, Céline; Chatelain, Florent; Michel, Olivier; Bacon, Roland; Piqueras, Laure; Bacher, Raphael; Ayasso, Hacheme

    2016-04-01

    We present SELFI, the Source Emission Line FInder, a new Bayesian method optimized for detection of faint galaxies in Multi Unit Spectroscopic Explorer (MUSE) deep fields. MUSE is the new panoramic integral field spectrograph at the Very Large Telescope (VLT) that has unique capabilities for spectroscopic investigation of the deep sky. It has provided data cubes with 324 million voxels over a single 1 arcmin2 field of view. To address the challenge of faint-galaxy detection in these large data cubes, we developed a new method that processes 3D data either for modeling or for estimation and extraction of source configurations. This object-based approach yields a natural sparse representation of the sources in massive data fields, such as MUSE data cubes. In the Bayesian framework, the parameters that describe the observed sources are considered random variables. The Bayesian model leads to a general and robust algorithm where the parameters are estimated in a fully data-driven way. This detection algorithm was applied to the MUSE observation of Hubble Deep Field-South. With 27 h total integration time, these observations provide a catalog of 189 sources of various categories and with secured redshift. The algorithm retrieved 91% of the galaxies with only 9% false detection. This method also allowed the discovery of three new Lyα emitters and one [OII] emitter, all without any Hubble Space Telescope counterpart. We analyzed the reasons for failure for some targets, and found that the most important limitation of the method is when faint sources are located in the vicinity of bright spatially resolved galaxies that cannot be approximated by the Sérsic elliptical profile. The software and its documentation are available on the MUSE science web service (muse-vlt.eu/science).

  13. Discovery of Faint Radio Structures over 50 Square Degrees Down to 3 arcmin Scales near the NGP

    NASA Astrophysics Data System (ADS)

    Kronberg, Philipp P.; Kothes, R.; Salter, C. J.; Perillat, P.

    2006-12-01

    We present a deep, 8o diameter, 0.4 GHz radio image near the North Galactic Pole using a first time combination of the Arecibo 305-m telescope and the wide-angle interferometer at the DRAO. The uniquely complementary nature of these two instruments permits a distortion-free image sensitive to radiation on all scales from 8o down to that of an individual galaxy halo at the 100 Mpc distance of the Great Wall, all in a single pointing. Faint, previously unseen diffuse patches of distributed radio ``glow'' are detected, well above our detection limit, and on a range of angular scales. The emission could compete with CMB fluctuations as a CMB foreground at high multipole scales around 30GHz if its radio spectrum continues up to these GHz bands. This new faint radio emission appears to be a mix of foreground Galactic, and extragalactic ``glow’. The latter implies i.g. magnetic field strengths at or above 0.1 microgauss on Mpc scales in certain areas. A striking anticorrelation is also found between the diffuse radio glow and some regions of high optical galaxy surface density. This suggests that cosmological Large Scale Structure (LSS), normally defined by the baryonic (and/or dark) matter density, is not uniquely traced by the faint continuum radio glow. More likely, the radio glow is a proxy for IGM energy density, at least in the low redshift universe. Its detailed relation to the WHIM, and diffuse X-ray glow is unclear, and must await future, more sensitive detectors for these latter two IGM components. Support for this project is acknowledged from the DOE's LDRD program at LANL, the Natural Sciences and Engineering Research Council of Canada (NSERC), and the National Science Foundation.

  14. Monitoring the long outburst of the very-faint X-ray transient XMMU J174716.1-281048

    NASA Astrophysics Data System (ADS)

    Del Santo, Melania; Romano, Patrizia; Sidoli, Lara

    2012-05-01

    XMMU J174716.1-281048 is a burster, very faint X-ray transient (VFXT), located at 0.9 degree off the Galactic Centre. It has been classified as the first "quasi-persistent" VFXT (Del Santo et al. 2007, A&A, 468, L17) showing a prolonged accretion episode of many years (ATel #1078). In order to monitor this peculiar long outburst, we thus observe the source once per year. A new ToO with Swift/XRT has been performed on 2012-05-06 16:44:24 UT to 18:26:56 UT (2ks net exposure).

  15. Properties of galaxies at the faint end of the Hα luminosity function at z ~ 0.62

    NASA Astrophysics Data System (ADS)

    Gómez-Guijarro, Carlos; Gallego, Jesús; Villar, Víctor; Rodríguez-Muñoz, Lucía; Clément, Benjamin; Cuby, Jean-Gabriel

    2016-07-01

    Context. Studies measuring the star formation rate density, luminosity function, and properties of star-forming galaxies are numerous. However, it exists a gap at 0.5 < z < 0.8 in Hα-based studies. Aims: Our main goal is to study the properties of a sample of faint Hα emitters at z ~ 0.62. We focus on their contribution to the faint end of the luminosity function and derived star formation rate density, characterising their morphologies and basic photometric and spectroscopic properties. Methods: We use a narrow-band technique in the near-infrared, with a filter centred at 1.06 μm. The data come from ultra-deep VLT/HAWK-I observations in the GOODS-S field with a total of 31.9 h in the narrow-band filter. In addition to our survey, we mainly make use of ancillary data coming from the CANDELS and Rainbow Cosmological Surveys Database, from the 3D-HST for comparison, and also spectra from the literature. We perform a visual classification of the sample and study their morphologies from structural parameters available in CANDELS. In order to obtain the luminosity function, we apply a traditional V/Vmax method and perform individual extinction corrections for each object to accurately trace the shape of the function. Results: Our 28 Hα-selected sample of faint star-forming galaxies reveals a robust faint-end slope of the luminosity function α = - 1.46-0.08+0.16 . The derived star formation rate density at z ~ 0.62 is ρSFR = 0.036-0.008+0.012 M⊙ yr-1 Mpc-3 . The sample is mainly composed of disks, but an important contribution of compact galaxies with Sérsic indexes n ~ 2 display the highest specific star formation rates. Conclusions: The luminosity function at z ~ 0.62 from our ultra-deep data points towards a steeper α when an individual extinction correction for each object is applied. Compact galaxies are low-mass, low-luminosity, and starburst-dominated objects with a light profile in an intermediate stage from early to late types. Based on observations

  16. Red Spot Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This brief movie shows counterclockwise atmospheric motion around Jupiter's Great Red Spot. The clip was made from blue-filter images taken with the narrow-angle camera on NASA's Cassini spacecraft during seven separate rotations of Jupiter between Oct. 1 and Oct. 5, 2000.

    The clip also shows the eastward and westward motion of the zonal jets, seen as the horizontal stripes flowing in opposite directions. The zonal jets circle the planet. As far as can be determined from both Earth-based and spacecraft measurements, the positions and speeds of the jets have not changed for 100 years. Since Jupiter is a fluid planet without a solid boundary, the jet speeds are measured relative to Jupiter's magnetic field, which rotates, wobbling like a top because of its tilt, every 9 hours 55.5 minutes. The movie shows motions in the magnetic reference frame, so winds to the west correspond to features that are rotating a little slower than the magnetic field, and eastward winds correspond to features rotating a little faster.

    Because the Red Spot is in the southern hemisphere, the direction of motion indicates it is a high-pressure center. Small bright clouds appear suddenly to the west of the Great Red Spot. Scientists suspect these small white features are lightning storms. The storms eventually merge with the Red Spot and surrounding jets, and may be the main energy source for the large-scale features.

    The smallest features in the movie are about 500 kilometers (about 300 miles) across. The spacing of the movie frames in time is not uniform; some consecutive images are separated by two Jupiter rotations, and some by one. The images have been re-projected using a simple cylindrical map projection. They show an area from 50 degrees north of Jupiter's equator to 50 degrees south, extending 100 degrees east-west, about one quarter of Jupiter's circumference.

    Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet

  17. Optical, radio and x-ray radiation of red sprites produced by runaway air breakdown

    SciTech Connect

    Yukhimuk, V.; Roussel-Dupre, R.; Symbalisty, E.; Taranenko, Y.

    1997-04-01

    The authors use the runaway air breakdown model of upward discharges to calculate optical, radio, and X-ray radiation generated by red sprites. Red sprites are high altitude (up to 90 km) lightning discharges. Aircraft based observations show that sprites are predominantly red in color at altitudes above {approximately}55 km with faint blue tendrils, which extend downward to an altitude of 40 km; the duration of a single sprite is less than 17 ms, their maximum brightness is about 600 kR, and estimated total optical energy is about 1--5 kJ per event. The ground based observations show similar results, and provide some additional information on spatial and temporal structure of sprites, and on sprite locations. One difference between aircraft and ground-based observations is that blue tendrils are rarely observed from the ground. Sprites usually occur above the anvils of large mesoscale convective systems and correlate with strong positive cloud to ground discharge. Upward discharges are the most probable source of X-ray emission observed above large thunderstorm complexes by the Compton Gamma-ray Observatory. To escape the atmosphere these {gamma}-rays must originate above 25 km altitude. Red sprites are usually observed at altitudes higher than 50 km, and are therefore a likely source of this x-ray emission.

  18. WHAT DETERMINES THE SIZES OF RED EARLY-TYPE GALAXIES?

    SciTech Connect

    Lee, Joon Hyeop; Kim, Minjin; Ree, Chang Hee; Kim, Sang Chul; Lee, Jong Chul; Lee, Hye-Ran; Jeong, Hyunjin; Seon, Kwang-Il; Kyeong, Jaemann; Oh, Kyuseok

    2013-01-01

    The sizes of galaxies are known to be closely related with their masses, luminosities, redshifts, and morphologies. However, when we fix these quantities and morphology, we still find large dispersions in the galaxy size distribution. We investigate the origin of these dispersions for red early-type galaxies using two SDSS-based catalogs. We find that the sizes of faint galaxies (log (M{sub dyn}/M{sub Sun }) {approx}< 10.3 or {sup 0.1} M{sub r} {approx}> -19.5, where {sup 0.1} M{sub r} is the r-band absolute magnitude, k-corrected to z = 0.1) are affected more significantly by luminosity, while the sizes of bright galaxies (log (M{sub dyn}/M{sub Sun }) {approx}> 11.4 or {sup 0.1} M{sub r} {approx}< -21.4) are by dynamical mass. At fixed mass and luminosity, the sizes of low-mass galaxies (log (M{sub dyn}/M{sub Sun }) {approx} 10.45 and {sup 0.1} M{sub r} {approx} -19.8) are relatively less sensitive to their colors, color gradients, and axis ratios. On the other hand, the sizes of intermediate-mass (log (M{sub dyn}/M{sub Sun }) {approx} 10.85 and {sup 0.1} M{sub r} {approx} -20.4) and high-mass (log (M{sub dyn}/M{sub Sun }) {approx} 11.25 and {sup 0.1} M{sub r} {approx} -21.0) galaxies significantly depend on those parameters, in the sense that larger red early-type galaxies have bluer colors, more negative color gradients (bluer outskirts), and smaller axis ratios. These results indicate that the sizes of intermediate- and high-mass red early-type galaxies are significantly affected by their recent minor mergers or rotations, whereas the sizes of low-mass red early-type galaxies are affected by some other mechanisms. Major dry mergers also seem to have influenced on the size growth of high-mass red early-type galaxies.

  19. Sarcocystis spp. Infection in two Red Panda Cubs (Ailurus fulgens).

    PubMed

    Zoll, W M; Needle, D B; French, S J; Lim, A; Bolin, S; Langohr, I; Agnew, D

    2015-01-01

    Two neonatal male red panda (Ailurus fulgens) littermates were submitted for necropsy examination. One animal was found dead with no prior signs of illness; the other had a brief history of laboured breathing. Post-mortem examination revealed disseminated protozoal infection. To further characterize the causative agent, transmission electron microscopy (TEM), immunohistochemistry (IHC), polymerase chain reaction (PCR) and amplification and nucleic acid sequencing were performed. IHC was negative for Toxoplasma gondii and Neospora caninum, but was positive for a Sarcocystis spp. TEM of cardiac muscle and lung revealed numerous intracellular apicomplexan protozoa within parasitophorous vacuoles. PCR and nucleic acid sequencing of partial 18S rRNA and the internal transcribed spacer (ITS)-1 region confirmed a Sarcocystis spp. that shared 99% sequence homology to Sarcocystis neurona and Sarcocystis dasypi. This represents the first report of sarcocystosis in red pandas. The histopathological, immunohistochemical, molecular and ultrastructural findings are supportive of vertical transmission resulting in fatal disseminated disease. PMID:26054654

  20. The FIRST Survey: Faint Images of the Radio Sky at Twenty Centimeters

    NASA Astrophysics Data System (ADS)

    Becker, Robert H.; White, Richard L.; Helfand, David J.

    1995-09-01

    The FIRST survey to produce Faint Images of the Radio Sky at Twenty centimeters is now underway using the NRAO Very Large Array. We describe here the scientific motivation for a large-area sky survey at radio frequencies which has a sensitivity and angular resolution comparable to the Palomar Observatory Sky Survey, and we recount the history that led to the current survey project. The technical design of the survey is covered in detail, including a description and justification of the grid pattern chosen, the rationale behind the integration time and angular resolution selected, and a summary of the other considerations which informed our planning for the project. A comprehensive description of the automated data analysis pipeline we have developed is presented. We also report here the results of the first year of FIRST observations. A total of 144 hr of time in 1993 April and May was used for a variety of tests, as well as to cover an initial strip of the survey extending between 07h 15m and 16h 30m in a 2°.8 wide declination zone passing through the local zenith (28.2 <δ < 31.0). A total of 2153 individual pointings yielded an image database containing 1039 merged images 46'.5 × 34'.5 in extent with 1".8 pixels and a typical rms of 0.13 mJy. A catalog derived from this 300 deg2 region contains 28,000 radio sources. We have performed extensive tests on the images and source list in order to establish the photometric and astrometric accuracy of these data products. We find systematic astrometric errors of < 0".05 individual sources down to the 1 mJy survey flux density threshold have 90% confidence error circles with radii of < 1". CLEAN bias introduces a systematic underestimate of point-source flux densities of ˜0.25 mJy; the bias is more severe for extended sources. Nonetheless, a comparison with a published deep survey field demonstrates that we successfully detect 39/49 sources with integrated flux densities greater than 0.75 mJy, including 19 of 20