Science.gov

Sample records for faint red sequence

  1. 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.

  2. Fainting

    MedlinePlus

    ... tunnel vision) or noises are fading into the background. Causes Fainting may occur while or after you: ... a seizure or heart rhythm disturbance), and to figure out the cause of the fainting episode. If ...

  3. Fainting

    MedlinePlus

    ... brain does not get enough oxygen. You lose consciousness, or "pass out," for a brief time (usually ... syncope, exertional syncope, fainting, hyperventilation, hypovolemic syncope, lose consciousness, loss of consciousness, micturition syncope, orthostatic syncope, pass ...

  4. Fainting

    MedlinePlus

    ... En Español Making a Change – Your Personal Plan Hot Topics Am I in a Healthy Relationship? Who ... reasons why teens faint: Physical triggers. Getting too hot or being in a crowded, poorly ventilated setting ...

  5. 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.

  6. 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.

  7. The faint intergalactic-medium red-shifted emission balloon: future UV observations with EMCCDs

    NASA Astrophysics Data System (ADS)

    Kyne, Gillian; Hamden, Erika T.; Lingner, Nicole; Morrissey, Patrick; Nikzad, Shouleh; Martin, D. Christopher

    2016-08-01

    We present the latest developments in our joint NASA/CNES suborbital project. This project is a balloon-borne UV multi-object spectrograph, which has been designed to detect faint emission from the circumgalactic medium (CGM) around low redshift galaxies. One major change from FIREBall-1 has been the use of a delta-doped Electron Multiplying CCD (EMCCD). EMCCDs can be used in photon-counting (PC) mode to achieve extremely low readout noise (¡ 1e-). Our testing initially focused on reducing clock-induced-charge (CIC) through wave shaping and well depth optimisation with the CCD Controller for Counting Photons (CCCP) from Nüvü. This optimisation also includes methods for reducing dark current, via cooling and substrate voltage adjustment. We present result of laboratory noise measurements including dark current. Furthermore, we will briefly present some initial results from our first set of on-sky observations using a delta-doped EMCCD on the 200 inch telescope at Palomar using the Palomar Cosmic Web Imager (PCWI).

  8. VizieR Online Data Catalog: Kepler faint red giants (Mathur+, 2016)

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    From the H14 catalog (Huber+, 2014, J/ApJS/211/2), we selected GKM dwarfs according to the following criteria: logg>=4.25 and Teff<=5500K. We also added a few tens of stars from the asteroseismic sample of solar-like stars from Chaplin et al. (2011ApJ...732...54C) where red-giant-like oscillations were detected. These additional stars have Teff>5500K. (4 data files).

  9. RED: the analysis, management and dissemination of expressed sequence tags.

    PubMed

    Everitt, R; Minnema, S E; Wride, M A; Koster, C S; Hance, J E; Mansergh, F C; Rancourt, D E

    2002-12-01

    The Rancourt EST Database (RED) is a web-based system for the analysis, management, and dissemination of expressed sequence tags (ESTs). RED represents a flexible template DNA sequence database that can be easily manipulated to suit the needs of other laboratories undertaking mid-size sequencing projects.

  10. 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 ...

  11. The Nature of Red-Sequence Cluster Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Kashur, Lane; Barkhouse, Wayne; Sultanova, Madina; Kalawila Vithanage, Sandanuwa; Archer, Haylee; Foote, Gregory; Mathew, Elijah; Rude, Cody; Lopez-Cruz, Omar

    2017-01-01

    Preliminary analysis of the red-sequence galaxy population from a sample of 57 low-redshift galaxy clusters observed using the KPNO 0.9m telescope and 74 clusters from the WINGS dataset, indicates that a small fraction of red-sequence galaxies have a morphology consistent with spiral systems. For spiral galaxies to acquire the color of elliptical/S0s at a similar luminosity, they must either have been stripped of their star-forming gas at an earlier epoch, or contain a larger than normal fraction of dust. To test these ideas we have compiled a sample of red-sequence spiral galaxies and examined their infrared properties as measured by 2MASS, WISE, Spitzer, and Herschel. These IR data allows us to estimate the amount of dust in each of our red-sequence spiral galaxies. We compare the estimated dust mass in each of these red-sequence late-type galaxies with spiral galaxies located in the same cluster field but having colors inconsistent with the red-sequence. We thus provide a statistical measure to discriminate between purely passive spiral galaxy evolution and dusty spirals to explain the presence of these late-type systems in cluster red-sequences.

  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. 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

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

    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 YJKs 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 ~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. Based on observations obtained at the European Southern Observatory using the ESO Very Large Telescope on Cerro Paranal through ESO program 386.A-0514(A).

  14. Insertion sequences enrichment in extreme Red sea brine pool vent.

    PubMed

    Elbehery, Ali H A; Aziz, Ramy K; Siam, Rania

    2017-03-01

    Mobile genetic elements are major agents of genome diversification and evolution. Limited studies addressed their characteristics, including abundance, and role in extreme habitats. One of the rare natural habitats exposed to multiple-extreme conditions, including high temperature, salinity and concentration of heavy metals, are the Red Sea brine pools. We assessed the abundance and distribution of different mobile genetic elements in four Red Sea brine pools including the world's largest known multiple-extreme deep-sea environment, the Red Sea Atlantis II Deep. We report a gradient in the abundance of mobile genetic elements, dramatically increasing in the harshest environment of the pool. Additionally, we identified a strong association between the abundance of insertion sequences and extreme conditions, being highest in the harshest and deepest layer of the Red Sea Atlantis II Deep. Our comparative analyses of mobile genetic elements in secluded, extreme and relatively non-extreme environments, suggest that insertion sequences predominantly contribute to polyextremophiles genome plasticity.

  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. A Tale of Giants and Dwarfs: How the Red Sequence in Clusters Grew Over The Last 9.5 Gyr.

    NASA Astrophysics Data System (ADS)

    Rudnick, Gregory; Tran, K.; Papovich, C.

    2012-01-01

    Understanding how star formation was turned off in galaxies over time and how these passive galaxies then evolve is a major focus of galaxy evolution studies. Equally important is uncovering what role environmental processes play. Here we discuss the evolution of the red sequence in galaxy clusters over the past 9.5 Gyr of cosmic time, as revealed by deep YJK imaging with HAWK-I/VLT of a confirmed massive cluster at z=1.62. We use these data to measure the luminosity function (LF) of red sequence galaxies and chart the growth of the passive sequence. We compare the shape of the LF and the total light on the red sequence in the z=1.62 cluster with clusters at 0.4faint magnitudes consistent with seen at z=0.7 in EDisCS clusters. Interestingly, there is an apparent deficit of bright red galaxies in the z=1.62 cluster when compared to likely descendant clusters at lower redshift. After correcting for the evolving mass to light ratio, we find that the total amount of stellar mass on the red sequence increases rapidly from z=1.62 to z=0.7 and then increases more slowly to z=0. We will discuss scenarios for how the rapid growth in the total light over a period of 3.2 Gyr can be reconciled with the lack of evolution in the shape of the luminosity function. One possibility is that galaxies are added to the red sequence, but that other processes, e.g. dry merging, must be at play to explain the lack of evolution in the LF shape and to populate the bright end. At z<0.7 the amount of merging in the deep cluster potential well decreases and the LF shape begins to rapidly evolve.

  18. 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.

    2016-11-01

    We present the Red Cluster Sequence 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. 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 four-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 Canadian Astronomy Data Centre 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.

  19. The Next Generation Virgo Cluster Survey (NGVS). XXIV. The Red Sequence to ~106 L ⊙ and Comparisons with Galaxy Formation Models

    NASA Astrophysics Data System (ADS)

    Roediger, Joel C.; Ferrarese, Laura; Côté, Patrick; MacArthur, Lauren A.; Sánchez-Janssen, Rúben; Blakeslee, John P.; Peng, Eric W.; Liu, Chengze; Munoz, Roberto; Cuillandre, Jean-Charles; Gwyn, Stephen; Mei, Simona; Boissier, Samuel; Boselli, Alessandro; Cantiello, Michele; Courteau, Stéphane; Duc, Pierre-Alain; Lançon, Ariane; Mihos, J. Christopher; Puzia, Thomas H.; Taylor, James E.; Durrell, Patrick R.; Toloba, Elisa; Guhathakurta, Puragra; Zhang, Hongxin

    2017-02-01

    We use deep optical photometry from the Next Generation Virgo Cluster Survey (NGVS) to investigate the color–magnitude diagram for the galaxies inhabiting the core of this cluster. The sensitivity of the NGVS imaging allows us to continuously probe galaxy colors over a factor of ∼2 × 105 in luminosity, from brightest cluster galaxies to scales overlapping classical satellites of the Milky Way ({M}g\\prime ∼ ‑9 M * ∼ 106 M ⊙), within a single environment. Remarkably, we find the first evidence that the red sequence (RS) flattens in all colors at the faint-magnitude end (starting between ‑14 ≤ {M}g\\prime ≤ ‑13, around M * ∼ 4 × 107 M ⊙), with the slope decreasing to ∼60% or less of its value at brighter magnitudes. This could indicate that the stellar populations of faint dwarfs in Virgo’s core share similar characteristics (e.g., constant mean age) over ∼3 mag in luminosity, suggesting that these galaxies were quenched coevally, likely via pre-processing in smaller hosts. We also compare our results to galaxy formation models, finding that the RS in model clusters have slopes at intermediate magnitudes that are too shallow, and in the case of semianalytic models, do not reproduce the flattening seen at both extremes (bright/faint) of the Virgo RS. Deficiencies in the chemical evolution of model galaxies likely contribute to the model-data discrepancies at all masses, while overly efficient quenching may also be a factor at dwarf scales. Deep UV and near-IR photometry are required to unambiguously diagnose the cause of the faint-end flattening.

  20. 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.

  1. Fainting: First Aid

    MedlinePlus

    ... brain is momentarily inadequate, causing you to lose consciousness. This loss of consciousness is usually brief. Fainting can have no medical ... be a serious disorder. Therefore, treat loss of consciousness as a medical emergency until the signs and ...

  2. Dizziness and Fainting Spells

    MedlinePlus

    ... or Animals Genitals and Urinary Tract Glands & Growth Head Neck & Nervous System Heart Infections Learning Disabilities Obesity Orthopedic ... Vaccine Preventable Diseases Healthy Children > Health Issues > Conditions > Head Neck & Nervous System > Dizziness and Fainting Spells Health Issues ...

  3. 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.

  4. Draft Genome Sequence of Lactobacillus plantarum XJ25 Isolated from Chinese Red Wine

    PubMed Central

    Zhao, Meijing; Tian, Yu

    2016-01-01

    Here, we present the draft genome sequence of Lactobacillus plantarum XJ25, isolated from Chinese red wine that had undergone spontaneous malolactic fermentation, which consists of 25 contigs and is 3,218,018 bp long. PMID:27856576

  5. 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.

  6. 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

  7. EVIDENCE FOR THE UNIVERSALITY OF PROPERTIES OF RED-SEQUENCE GALAXIES IN X-RAY- AND RED-SEQUENCE-SELECTED CLUSTERS AT z ∼ 1

    SciTech Connect

    Foltz, R.; Wilson, G.; DeGroot, A.; Rettura, A.; Van der Burg, R. F. J.; Lidman, C.; Demarco, R.; Nantais, Julie; Yee, H. E-mail: gillian.wilson@ucr.edu E-mail: arettura@astro.caltech.edu E-mail: avmuzzin@ast.cam.ac.uk E-mail: rdemarco@astro-udec.cl E-mail: hyee@astro.utoronto.ca

    2015-10-20

    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.

  8. 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.

  9. 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.

  10. Satellite DNA Sequences in Canidae and Their Chromosome Distribution in Dog and Red Fox.

    PubMed

    Vozdova, Miluse; Kubickova, Svatava; Cernohorska, Halina; Fröhlich, Jan; Rubes, Jiri

    2016-01-01

    Satellite DNA is a characteristic component of mammalian centromeric heterochromatin, and a comparative analysis of its evolutionary dynamics can be used for phylogenetic studies. We analysed satellite and satellite-like DNA sequences available in NCBI for 4 species of the family Canidae (red fox, Vulpes vulpes, VVU; domestic dog, Canis familiaris, CFA; arctic fox, Vulpes lagopus, VLA; raccoon dog, Nyctereutes procyonoides procyonoides, NPR) by comparative sequence analysis, which revealed 86-90% intraspecies and 76-79% interspecies similarity. Comparative fluorescence in situ hybridisation in the red fox and dog showed signals of the red fox satellite probe in canine and vulpine autosomal centromeres, on VVUY, B chromosomes, and in the distal parts of VVU9q and VVU10p which were shown to contain nucleolus organiser regions. The CFA satellite probe stained autosomal centromeres only in the dog. The CFA satellite-like DNA did not show any significant sequence similarity with the satellite DNA of any species analysed and was localised to the centromeres of 9 canine chromosome pairs. No significant heterochromatin block was detected on the B chromosomes of the red fox. Our results show extensive heterogeneity of satellite sequences among Canidae and prove close evolutionary relationships between the red and arctic fox.

  11. Complete mitochondrial genome sequence of northeastern red deer (Cervus elaphus xanthopygus).

    PubMed

    Shao, Yuanchen; Su, Weilin; Liu, Huamiao; Zha, Daiming; Zhang, Ranran; Xing, Xiumei

    2016-01-01

    The complete mitochondrial genome of the northeastern red deer, Cervus elaphus xanthopygus, was determined by accurate polymerase chain reaction. The entire genome is 16,416 bp in length and contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 1 control region, all of which are arranged in a typical vertebrate manner. The overall base composition of the northeastern red deer's mitochondrial genome is 33.3% of A, 24.3% of C, 28.9% of T and 13.5% of G. A termination-associated sequence and several conserved central sequence block domains were discovered within the control region.

  12. 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.

  13. 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

  14. 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.

  15. Sequence analysis of a canine parvovirus isolated from a red panda (Ailurus fulgens) in China.

    PubMed

    Qin, Qin; Loeffler, I Kati; Li, Ming; Tian, Kegong; Wei, Fuwen

    2007-06-01

    Canine parvovirus (CPV) was first recognized in the late 1970 s in dogs and has mutated and spread throughout the world in canid and felid species since then. In this study, a novel CPV was isolated from the endangered red panda (Ailurus fulgens) in China. Nucleotide and phylogenetic analysis of the capsid protein VP2 gene classified the red panda parvovirus (RPPV) as a CPV-2a type. Substitution of Val for Gly at the conserved 300 residue in RPPV presents an unusual variation in the CPV-2a amino acid sequence and is further evidence for the continuing evolution of the virus. The 300 residue is important in distinguishing the antigenicity and host range of CPVs. The clinical significance and population impact of RPPV infection in captive red pandas in China is unknown and is an important topic for future research.

  16. 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

  17. 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.

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

    PubMed

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

    2016-07-08

    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.

  19. 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.

  20. Linkage Mapping and Comparative Genomics of Red Drum (Sciaenops ocellatus) Using Next-Generation Sequencing.

    PubMed

    Hollenbeck, Christopher M; Portnoy, David S; Wetzel, Dana; Sherwood, Tracy A; Samollow, Paul B; Gold, John R

    2017-03-10

    Developments in next-generation sequencing allow genotyping of thousands of genetic markers across hundreds of individuals in a cost-effective manner. Because of this, it is now possible to rapidly produce dense genetic linkage maps for nonmodel species. Here, we report a dense genetic linkage map for red drum, a marine fish species of considerable economic importance in the southeastern United States and elsewhere. We used a prior microsatellite-based linkage map as a framework and incorporated 1794 haplotyped contigs derived from high-throughput, reduced representation DNA sequencing to produce a linkage map containing 1794 haplotyped restriction-site associated DNA (RAD) contigs, 437 anonymous microsatellites, and 44 expressed sequence-tag-linked microsatellites (EST-SSRs). A total of 274 candidate genes, identified from transcripts from a preliminary hydrocarbon exposure study, were localized to specific chromosomes, using a shared synteny approach. The linkage map will be a useful resource for red drum commercial and restoration aquaculture, and for better understanding and managing populations of red drum in the wild.

  1. Linkage Mapping and Comparative Genomics of Red Drum (Sciaenops ocellatus) Using Next-Generation Sequencing

    PubMed Central

    Hollenbeck, Christopher M.; Portnoy, David S.; Wetzel, Dana; Sherwood, Tracy A.; Samollow, Paul B.; Gold, John R.

    2017-01-01

    Developments in next-generation sequencing allow genotyping of thousands of genetic markers across hundreds of individuals in a cost-effective manner. Because of this, it is now possible to rapidly produce dense genetic linkage maps for nonmodel species. Here, we report a dense genetic linkage map for red drum, a marine fish species of considerable economic importance in the southeastern United States and elsewhere. We used a prior microsatellite-based linkage map as a framework and incorporated 1794 haplotyped contigs derived from high-throughput, reduced representation DNA sequencing to produce a linkage map containing 1794 haplotyped restriction-site associated DNA (RAD) contigs, 437 anonymous microsatellites, and 44 expressed sequence-tag-linked microsatellites (EST-SSRs). A total of 274 candidate genes, identified from transcripts from a preliminary hydrocarbon exposure study, were localized to specific chromosomes, using a shared synteny approach. The linkage map will be a useful resource for red drum commercial and restoration aquaculture, and for better understanding and managing populations of red drum in the wild. PMID:28122951

  2. Faint Infrared-Excess Field Galaxies: FROGs

    NASA Astrophysics Data System (ADS)

    Moustakas, L. A.; Davis, M.; Zepf, S. E.; Bunker, A. J.

    Deep near-infrared and optical imaging surveys in the field reveal a curious population of galaxies that are infrared-bright (I-K>4), yet with relatively blue optical colors (V-I<2). Their surface density, several per square arcminute at K>20, is high enough that if placed at z>1 as our models suggest, their space densities are about one-tenth of phi-*. The colors of these ``faint red outlier galaxies'' (fROGs) may derive from exceedingly old underlying stellar populations, a dust-embedded starburst or AGN, or a combination thereof. Determining the nature of these fROGs, and their relation with the I-K>6 ``extremely red objects,'' has implications for our understanding of the processes that give rise to infrared-excess galaxies in general. We report on an ongoing study of several targets with HST & Keck imaging and Keck/LRIS multislit spectroscopy.

  3. Imaging stellar faint companions

    NASA Astrophysics Data System (ADS)

    Cagigal, Manuel P.; Canales, Vidal F.

    . The conclusion is that the use of the Dark Speckle technique in a compensated nulling interferometer could be a promising way to detect faint objects, although the application of the technique in the infrared range requires the development of appropriate detectors.

  4. 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.

  5. Morphological evolution of cluster red sequence galaxies in the past 9 Gyr

    NASA Astrophysics Data System (ADS)

    De Propris, Roberto; Bremer, Malcolm N.; Phillipps, Steven

    2016-10-01

    Galaxies arrive on the red sequences of clusters at high redshift (z > 1) once their star formation is quenched and evolve passively thereafter. However, we have previously found that cluster red sequence galaxies (CRSGs) undergo significant morphological evolution subsequent to the cessation of star formation, at some point in the past 9-10 Gyr. Through a detailed study of a large sample of cluster red sequence galaxies spanning 0.2 < z < 1.4 we elucidate the details of this evolution. Below z ˜ 0.5-0.6 (in the last 5-6 Gyr) there is little or no morphological evolution in the population as a whole, unlike in the previous 4-5 Gyr. Over this earlier time (i) disc-like systems with Sérsic n < 2 progressively disappear, as (ii) the range of their axial ratios similarly decreases, removing the most elongated systems (those consistent with thin discs seen at an appreciable inclination angle) and (iii) radial colour gradients (bluer outwards) decrease in an absolute sense from significant age-related gradients to a residual level consistent with the metallicity-induced gradients seen in low-redshift cluster members. The distribution of their effective radii shows some evidence of evolution, consistent with growth of at most a factor <1.5 between z ˜ 1.4 and ˜0.5, significantly less than for comparable field galaxies, while the distribution of their central (<1 kpc) bulge surface densities shows no evolution at least at z < 1. A simple model involving the fading and thickening of a disc component after comparatively recent quenching (after z ˜ 1.5) around an otherwise passively evolving older spheroid component is consistent with all of these findings.

  6. Insights into Korean red fox (Vulpes vulpes) based on mitochondrial cytochrome b sequence variation in East Asia.

    PubMed

    Yu, Jeong-Nam; Han, Sang-Hoon; Kim, Bang-Hwan; Kryukov, Alexey P; Kim, Soonok; Lee, Byoung-Yoon; Kwak, Myounghai

    2012-11-01

    The red fox (Vulpes vulpes) is the most widely distributed terrestrial carnivore in the world, occurring throughout most of North America, Europe, Asia, and North Africa. In South Korea, however, this species has been drastically reduced due to habitat loss and poaching. Consequently, it is classified as an endangered species in Korea. As a first step of a planned red fox restoration project, preserved red fox museum specimens were used to determine the genetic status of red foxes that had previously inhabited South Korea against red foxes from neighboring countries. Total eighty three mtDNA cytochrome b sequences, including 22 newly obtained East Asian red fox sequences and worldwide red fox sequences from NCBI, were clustered into three clades (i.e., I, II, and III) based on haplotype network and neighbor-joining trees. The mean genetic distance between clades was 2.0%. Clade III contained South Korean and other East Asian samples in addition to Eurasian and North Pacific individuals. In clade III, South Korean individuals were separated into two lineages of Eurasian and North Pacific groups, showing unclear phylogeographic structuring and admixture. This suggests that South Korean red fox populations may have been composed of individuals from these two different genetic lineages.

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. The far infra-red SEDs of main sequence and starburst galaxies

    NASA Astrophysics Data System (ADS)

    Cowley, William I.; Béthermin, Matthieu; del P. Lagos, Claudia; Lacey, Cedric G.; Baugh, Carlton M.; Cole, Shaun

    2017-01-01

    We compare observed far infra-red/sub-millimetre (FIR/sub-mm) galaxy spectral energy distributions (SEDs) of massive galaxies (M⋆ ≳ 1010 h-1 M⊙) derived through a stacking analysis with predictions from a new model of galaxy formation. The FIR SEDs of the model galaxies are calculated using a self-consistent model for the absorption and re-emission of radiation by interstellar dust based on radiative transfer calculations and global energy balance arguments. Galaxies are selected based on their position on the specific star formation rate (sSFR) - stellar mass (M⋆) plane. We identify a main sequence of star-forming galaxies in the model, i.e. a well defined relationship between sSFR and M⋆, up to redshift z ˜ 6. The scatter of this relationship evolves such that it is generally larger at higher stellar masses and higher redshifts. There is remarkable agreement between the predicted and observed average SEDs across a broad range of redshifts (0.5 ≲ z ≲ 4) for galaxies on the main sequence. However, the agreement is less good for starburst galaxies at z ≳ 2, selected here to have elevated sSFRs>10 × the main sequence value. We find that the predicted average SEDs are robust to changing the parameters of our dust model within physically plausible values. We also show that the dust temperature evolution of main sequence galaxies in the model is driven by star formation on the main sequence being more burst-dominated at higher redshifts.

  13. Comprehensive red blood cell and platelet antigen prediction from whole genome sequencing: proof of principle

    PubMed Central

    Westhoff, Connie M.; Uy, Jon Michael; Aguad, Maria; Smeland‐Wagman, Robin; Kaufman, Richard M.; Rehm, Heidi L.; Green, Robert C.; Silberstein, Leslie E.

    2015-01-01

    BACKGROUND There are 346 serologically defined red blood cell (RBC) antigens and 33 serologically defined platelet (PLT) antigens, most of which have known genetic changes in 45 RBC or six PLT genes that correlate with antigen expression. Polymorphic sites associated with antigen expression in the primary literature and reference databases are annotated according to nucleotide positions in cDNA. This makes antigen prediction from next‐generation sequencing data challenging, since it uses genomic coordinates. STUDY DESIGN AND METHODS The conventional cDNA reference sequences for all known RBC and PLT genes that correlate with antigen expression were aligned to the human reference genome. The alignments allowed conversion of conventional cDNA nucleotide positions to the corresponding genomic coordinates. RBC and PLT antigen prediction was then performed using the human reference genome and whole genome sequencing (WGS) data with serologic confirmation. RESULTS Some major differences and alignment issues were found when attempting to convert the conventional cDNA to human reference genome sequences for the following genes: ABO, A4GALT, RHD, RHCE, FUT3, ACKR1 (previously DARC), ACHE, FUT2, CR1, GCNT2, and RHAG. However, it was possible to create usable alignments, which facilitated the prediction of all RBC and PLT antigens with a known molecular basis from WGS data. Traditional serologic typing for 18 RBC antigens were in agreement with the WGS‐based antigen predictions, providing proof of principle for this approach. CONCLUSION Detailed mapping of conventional cDNA annotated RBC and PLT alleles can enable accurate prediction of RBC and PLT antigens from whole genomic sequencing data. PMID:26634332

  14. 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

  15. 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.

  16. Determination of mitochondrial cytochrome B gene sequence for red deer (Cervus elaphus) and the differentiation of closely related deer meats.

    PubMed

    Matsunaga, T; Chikuni, K; Tanabe, R; Muroya, S; Nakai, H; Shibata, K; Yamada, J; Shinmura, Y

    1998-08-01

    The cytochrome b gene sequence for red deer was determined using the Dye Terminator Cycle Sequencing method and used for identification of deer meat in meat and meat products. Red deer showed a similarity of 94.1, 84.0, 81.1, 85.5 and 85.6% to sika deer (Cervus nippon), bovine, pigs, sheep and goats, respectively. To differentiate the deer meat, oligonucleotide primers RD-1(5'-TCATCGCAGCACTCGCTATAGTACACT-3'), RD-2(5'-ATCTCCAAGTAGGTCTGGTGCGAATAA-3') were designed for the region of the cytochrome b gene of red deer. The PCR amplified 194 bp fragments from red and sika deer, but no fragments from bovine, pig, chicken, sheep, goat, horse and rabbit DNA. Although cooking the meats reduced the PCR products, red deer could still be detected in meat heated at 120 °C. To discriminate between red and sika deer, these PCR products were digested by a restriction enzyme (EcoRI,BamHI,ScaI) and analyzed by 4% agorose gel electrophoresis. As a result, the red deer fragment was digested by EcoRI to 67/127 bp fragments but not by BamHI and ScaI. The sika deer fragment was digested to 48/146 bp and 49/145 bp fragments with the two other enzymes, and thus it is possible to differentiate between the two kinds of deer from the digestion pattern of restriction enzymes.

  17. The Binary Mass Transfer Origin of the Red Blue Straggler Sequence in M30

    NASA Astrophysics Data System (ADS)

    Xin, Y.; Ferraro, F. R.; Lu, P.; Deng, L.; Lanzoni, B.; Dalessandro, E.; Beccari, G.

    2015-03-01

    Two separated sequences of blue straggler stars (BSSs) have been revealed by Ferraro et al. in the color-magnitude diagram (CMD) of the Milky Way globular cluster M30. Their presence has been suggested to be related to the two BSS formation channels (namely, collisions and mass transfer in close binaries) operating within the same stellar system. The blue sequence was indeed found to be well reproduced by collisional BSS models. In contrast, no specific models for mass-transfer BSSs were available for an old stellar system like M30. Here we present binary evolution models, including case-B mass transfer and binary merging, specifically calculated for this cluster. We discuss in detail the evolutionary track of a 0.9 + 0.5 M ⊙ binary, which spends approximately 4 Gyr in the BSS region of the CMD of a 13 Gyr old cluster. We also run Monte Carlo simulations to study the distribution of mass-transfer BSSs in the CMD and to compare it with the observational data. Our results show that (1) the color and magnitude distribution of synthetic mass-transfer BSSs defines a strip in the CMD that nicely matches the observed red-BSS sequence, thus providing strong support to the mass-transfer origin for these stars; (2) the CMD distribution of synthetic BSSs never attains the observed location of the blue-BSS sequence, thus reinforcing the hypothesis that the latter formed through a different channel (likely collisions); (3) most (~60%) of the synthetic BSSs are produced by mass-transfer models, while the remaining <40% requires the contribution from merger models.

  18. Chandra Observations of Faint LMXB's

    NASA Technical Reports Server (NTRS)

    Wilson, Colleen A.; Patel, S. K.; Kouveliotou, C.; vanderKlis, M.; Belloni, T.; Lewin, W. H. G.; Six, N. Frank (Technical Monitor)

    2002-01-01

    There exists a group of persistently faint galactic X-ray sources that based on their location in the galaxy, high Lx/Lopt, association with X-ray bursts, and absence of X-ray pulsations are thought to be low-mass X-ray binaries (LMXBs). We present results from Chandra observations for 7 of these systems: 1708-409, 1711-339, 1735-269, 1736-297, 1746-331, 1746.7-3224, and 1812-12. Improved locations for all sources, excluding 1736-297 and 1746-331 (which were not detected) are presented. Our observations are consistent with previously reported transient behavior of 1736-297, 1746-331, and 1711-339 (which we detect in one of two observations). Energy and power spectra are presented for 1735-269, 1711-339, and 1746.7-3224. The energy spectra are hard, consistent with typical faint LMXB spectra. Further, we present a newly discovered source, a very faint, soft, source, separated by 2.7' from 1746.7-3224.

  19. 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

  20. Faintness

    MedlinePlus

    ... yourself? About Stephen J. Schueler, M.D News Advertising How It Works FAQ for Consumers FAQ for Physicians Testimonials Site Map Terms of Use Contact Us FreeMD is provided for information purposes only and should not be used as a ...

  1. Fainting

    MedlinePlus

    ... usually because changes in the nervous system and circulatory_system cause a temporary drop in the amount of ... a lot of changes, including changes in the circulatory system. This leads to low blood pressure that may ...

  2. 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

  3. The Red Sequence at Birth in the Galaxy Cluster Cl J1449+0856 at z = 2

    NASA Astrophysics Data System (ADS)

    Strazzullo, V.; Daddi, E.; Gobat, R.; Valentino, F.; Pannella, M.; Dickinson, M.; Renzini, A.; Brammer, G.; Onodera, M.; Finoguenov, A.; Cimatti, A.; Carollo, C. M.; Arimoto, N.

    2016-12-01

    We use Hubble Space Telescope/WFC3 imaging to study the red population in the IR-selected, X-ray detected, low-mass cluster Cl J1449+0856 at z = 2, one of the few bona fide established clusters discovered at this redshift, and likely a typical progenitor of an average massive cluster today. This study explores the presence and significance of an early red sequence in the core of this structure, investigating the nature of red-sequence galaxies, highlighting environmental effects on cluster galaxy populations at high redshift, and at the same time underlining similarities and differences with other distant dense environments. Our results suggest that the red population in the core of Cl J1449+0856 is made of a mixture of quiescent and dusty star-forming galaxies, with a seedling of the future red sequence already growing in the very central cluster region, and already characterizing the inner cluster core with respect to lower-density environments. On the other hand, the color-magnitude diagram of this cluster is definitely different from that of lower-redshift z ≲ 1 clusters, as well as of some rare particularly evolved massive clusters at similar redshift, and it is suggestive of a transition phase between active star formation and passive evolution occurring in the protocluster and established lower-redshift cluster regimes.

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

    PubMed

    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.

  5. Temporal sequence of major biochemical events during Blood Bank storage of packed red blood cells

    PubMed Central

    Karon, Brad S.; van Buskirk, Camille M.; Jaben, Elizabeth A.; Hoyer, James D.; Thomas, David D.

    2012-01-01

    Background. We used sensitive spectroscopic techniques to measure changes in Band 3 oligomeric state during storage of packed red blood cells (RBC); these changes were compared to metabolic changes, RBC morphology, cholesterol and membrane protein loss, phospholipid reorganisation of the RBC membrane, and peroxidation of membrane lipid. The aim of the study was to temporally sequence major biochemical events occurring during cold storage, in order to determine which changes may underlie the structural defects in stored RBC. Materials and methods. Fifteen RBC units were collected from normal volunteers and stored under standard blood bank conditions; both metabolic changes and lipid parameters were measured by multiple novel assays including a new mass spectrometric measurement of isoprostane (lipid peroxidation) and flow cytometric assessment of CD47 expression. Band 3 oligomeric state was assessed by time-resolved phosphorescence anisotropy, and RBC morphology by microscopy of glutaraldehyde-fixed RBC. Results. Extracellular pH decreased and extracellular potassium increased rapidly during cold storage. Band 3 on the RBC membrane aggregated into large oligomers early in the storage period and coincident with changes in RBC morphology. Membrane lipid changes, including loss of unesterified cholesterol, lipid peroxidation and expression of CD47, also changed early during the storage period. In contrast loss of acetylcholinesterase activity and haemolysis of RBC occurred late during storage. Discussion. Our results demonstrate that changes in the macromolecular organisation of membrane proteins on the RBC occur early in storage and suggest that lipid peroxidation and/or oxidative damage to the membrane are responsible for irreversible morphological changes and loss of function during red cell storage. PMID:22507860

  6. Genome Sequences of Polyomaviruses from the Wild-Living Red Colobus (Piliocolobus badius) and Western Chimpanzee (Pan troglodytes verus).

    PubMed

    Ben Salem, Nicole; Leendertz, Fabian H; Ehlers, Bernhard

    2016-10-13

    We identified with PCR and sequencing the full genomes of the recently discovered Pan troglodytes verus polyomavirus 8 and Piliocolobus badius polyomavirus 2 in a western chimpanzee and a western red colobus free-ranging in Taï National Park of Côte d'Ivoire.

  7. Draft Genome Sequences of Semiconstitutive Red, Dry, and Rough Biofilm-Forming Commensal and Uropathogenic Escherichia coli Isolates

    PubMed Central

    Cimdins, Annika; Lüthje, Petra; Li, Fengyang; Ahmad, Irfan; Brauner, Annelie

    2017-01-01

    ABSTRACT Strains of Escherichia coli exhibit diverse biofilm formation capabilities. E. coli K-12 expresses the red, dry, and rough (rdar) morphotype below 30°C, whereas clinical isolates frequently display the rdar morphotype semiconstitutively. We sequenced the genomes of eight E. coli strains to subsequently investigate the molecular basis of semiconstitutive rdar morphotype expression. PMID:28126929

  8. 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

  9. 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.

  10. The Red Sequence of High-Redshift Clusters: A Comparison with Cosmological Galaxy Formation Models

    NASA Astrophysics Data System (ADS)

    Menci, N.

    2008-10-01

    We compare the results from a state-of-the-art semi-analytic model of galaxy formation with spectroscopic observations of the distant galaxy clusters observed in the range 1≲ z≲ 1.5. In our model we find that i) a well-defined, narrow red sequence (RS) is obtained already by z≈ 1.2; this is more populated than the field RS analogously to what observed and predicted at z=0; ii) the predicted RS colors and width have average values of 1 and 0.15, respectively, with a cluster-to-cluster variance. The width of the RS of cluster galaxy is 5-10 times lower than the corresponding field value; iii) The predicted distribution of stellar ages of RS galaxies at z=1.2 are peaked at the value τ=3.7 Gyr for both cluster and field; however, for the latter the distribution is significantly skewed toward lower ages. When compared with observations, the above findings show an overall consistency, although the average value ≈ 0.07 of the observed cluster RS width at z≈1.2 is smaller than the corresponding model central value. We discuss the physical origin and the significance of the above results in the framework of cosmological galaxy formation.

  11. 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.

  12. 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.

  13. 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.

  14. The Red Sequence of High-Redshift Clusters: A Comparison with Cosmological Galaxy Formation Models

    NASA Astrophysics Data System (ADS)

    Menci, N.; Rosati, P.; Gobat, R.; Strazzullo, V.; Rettura, A.; Mei, S.; Demarco, R.

    2008-10-01

    We compare the results from a state-of-the-art semianalytic model of galaxy formation with spectrophotometric observations of distant galaxy clusters observed in the range 0.8 <= z<= 1.3. We investigate the properties of their red sequence (RS) galaxies and compare them with those of the field at the same redshift. In our model we find that (1) a well-defined, narrow RS is obtained already by z ≈ 1.2; this is found to be more populated than the field RS, analogously to what is observed and predicted at z = 0; (2) the predicted U-V rest-frame colors and scatter of the cluster RS at z = 1.2 have average values of 1 and 0.15, respectively, with a cluster-to-cluster variance of ≈0.2 and ≈0.06, respectively. The scatter of the RS of cluster galaxies is ≈5 times smaller than the corresponding field value; (3) when the RS galaxies are considered, the mass growth histories of field and cluster galaxies at z ≈ 1.2 are similar, with 90% of the stellar mass of RS galaxies at z = 1.2 already formed at cosmic times t = 2.5 Gyr, and 50% at t = 1 Gyr; and (4) the predicted distribution of stellar ages of RS galaxies at z = 1.2 peaks at 3.7 Gyr for both cluster and field populations; however, for the latter the distribution is significantly skewed toward lower ages. When compared with observations, the above findings show an overall consistency, although the average value ΔU - V ≈ 0.07 of the observed cluster RS scatter at z ≈ 1.2 is smaller than the corresponding model central value. We discuss the physical origin and the significance of the above results in the framework of cosmological galaxy formation.

  15. 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.

  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. Interpretation of colors of faint galaxies

    SciTech Connect

    Kron, R.G.

    1980-10-01

    We present new calculations for evolving light in galaxies which allow the color distribution expected for faint field galaxies to be computed. We normalize the expected counts to data in catalogs of bright galaxies, and find that an excellent fit to Kron's faint photometry can be achieved with a Friedmann model and no other special assumptions.

  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. Testing Scaling Relations for Solar-like Oscillations from the Main Sequence to Red Giants Using Kepler Data

    NASA Astrophysics Data System (ADS)

    Huber, D.; Bedding, T. R.; Stello, D.; Hekker, S.; Mathur, S.; Mosser, B.; Verner, G. A.; Bonanno, A.; Buzasi, D. L.; Campante, T. L.; Elsworth, Y. P.; Hale, S. J.; Kallinger, T.; Silva Aguirre, V.; Chaplin, W. J.; De Ridder, J.; García, R. A.; Appourchaux, T.; Frandsen, S.; Houdek, G.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kawaler, S. D.; Kjeldsen, H.; Broomhall, A. M.; Corsaro, E.; Salabert, D.; Sanderfer, D. T.; Seader, S. E.; Smith, J. C.

    2011-12-01

    We have analyzed solar-like oscillations in ~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 (νmax), the large frequency separation (Δν), and oscillation amplitudes. We show that the difference of the Δν-νmax 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) s scaling nor the revised scaling relation by Kjeldsen & 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 ~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.

  20. Faint CV Monitoring at CBA Pretoria

    NASA Astrophysics Data System (ADS)

    Monard, L. A. G. B.

    2006-05-01

    The regular monitoring of faint cataclysmic variables (CV) is one of five observing programs that are run at CBA Pretoria. It started off in 2002 with about 120 CVs and related objects in the program. The intention was to observe those targets as often as possible with unfiltered CCD. There were continuous additions of more CVs by digging deeper in the CV atlas, new finds, and reclassified stars while some were taken off the list. At the end of 2004 the number of CVs in the observing program exceeded 200. With only one telescope and one observer and so many other things to observe, the actual number of snapshot CV observations have been much less than hoped. Despite this, the program has shown to be very successful. Publications have been referring to reported findings from this program while even more publications resulted from observing campaigns (time resolved photometry) dedicated to CVs that were found in outburst by observations at CBA Pretoria. In most cases they were the first real-time outburst detection of that CV. The present paper will not deal with those published or alerted finds but will show observing results of other CVs from the list just to give an indication of the broader meaningfulness of such a program. A selection of fifteen light curves obtained after three years of monitoring will be shown and discussed. The choice of the 15 stars was based on their possible interest and the fact that they have been positively observed on most occasions, since they were mostly brighter than magnitude 18 CR (unfiltered with red zero-point).

  1. 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...

  2. 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.

  3. 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.

  4. Food for the photometrists - Faint galaxies revealed

    NASA Astrophysics Data System (ADS)

    Malin, D. F.

    The advantages of photographic plates over CCD detectors for some types of astronomical photometry (uniformity over large areas and information-storage capacity) are discussed, and illustrated using images of faint galaxies and faint galactic structures. It is pointed out that the photographic amplification technique (Malin, 1978), although at present only qualitative, is much more time-efficient than digital scanning. Consideration is also given to the production of full-color images by superimposition of B, V, and R plates.

  5. Mass fainting in garment factories in Cambodia.

    PubMed

    Eisenbruch, Maurice

    2017-04-01

    This paper reports an ethnographic study of mass fainting among garment factory workers in Cambodia. Research was undertaken in 2010-2015 in 48 factories in Phnom Penh and 8 provinces. Data were collected in Khmer using nonprobability sampling. In participant observation with monks, factory managers, health workers, and affected women, cultural understandings were explored. One or more episodes of mass fainting occurred at 34 factories, of which 9 were triggered by spirit possession. Informants viewed the causes in the domains of ill-health/toxins and supernatural activities. These included "haunting" ghosts at factory sites in the wake of Khmer Rouge atrocities or recent fatal accidents and retaliating guardian spirits at sites violated by foreign owners. Prefigurative dreams, industrial accidents, or possession of a coworker heralded the episodes. Workers witnessing a coworker fainting felt afraid and fainted. When taken to clinics, some showed signs of continued spirit influence. Afterwards, monks performed ritual ceremonies to appease spirits, extinguish bonds with ghosts, and prevent recurrence. Decoded through its cultural motifs of fear and protest, contagion, forebodings, the bloody Khmer Rouge legacy, and trespass, mass fainting in Cambodia becomes less enigmatic.

  6. Going Faint and Variable: The Faint Sky Variability Survey

    NASA Astrophysics Data System (ADS)

    Groot, P.; Everett, M.; Howell, S.; Vreeswijk, P.; Huber, M.; van Paradijs, J.

    1999-12-01

    Using the Wide Field Camera on the 2.5m Isaac Newton Telescope on the island of La Palma, we are conducting a survey, covering a total of 50 sq. deg., specifically designed to search for photometrically and astrometrically variables stars. We can identify variability time-scales between tens of minutes and one year and we obtain color information (B,V,I) for all fields. The design and sensitivity of the WFC allows us to obtain light-curves at unprecedented limits and precisions ranging from 5 mmag errors at V=17 to 0.1 mag at V=24.5. Main targets of the survey include interacting close binary systems (CV, LMXBs, SXTs, AM CVn systems), RR Lyrae stars in the galactic halo, optical counterparts to Gamma-Ray Bursts, Kuiper Belt Objects and high proper motion stars in the Solar Neighborhood. We also have identified numerous very red sources likely to be very low-mass stars and brown dwarfs. We will present the results of our first year of observations which cover a total of 9 square degrees.

  7. 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.

  8. 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.

  9. Generation of 10,154 expressed sequence tags from a leafy gametophyte of a marine red alga, Porphyra yezoensis.

    PubMed

    Nikaido, I; Asamizu, E; Nakajima, M; Nakamura, Y; Saga, N; Tabata, S

    2000-06-30

    A total of 10,154 5'-end expressed sequence tags (EST) were established from the normalized and size-selected cDNA libraries of a marine red alga, Porphyra yezoensis. Among the ESTs, 2140 were unique species, and the remaining 8014 were grouped into 1127 species. Database search of the 3267 non-redundant ESTs by BLAST algorithm showed that the sequences of 1080 species (33.1%) have similarity to those of registered genes from various organisms including higher plants, mammals, yeasts, and cyanobacteria, while 2187 (66.9%) are novel. Codon usage analysis in the coding regions of 101 non-redundant EST groups showing significant similarity to known genes indicated the higher GC contents at the third position of codons (79.4%) than the first (62.2%) and the second position (45.0%), suggesting that the genome has been exposed to high GC pressure during evolution. The sequence data of individual ESTs are available at the web site http://www.kazusa.or.jp/en/plant/porphyra/EST/.

  10. 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.

  11. 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.

  12. DNA sequence variation in the mitochondrial control region of red-backed voles (Clethrionomys).

    PubMed

    Matson, C W; Baker, R J

    2001-08-01

    The complete mitochondrial DNA (mtDNA) control region was sequenced for 71 individuals from five species of the rodent genus Clethrionomys both to understand patterns of variation and to explore the existence of previously described domains and other elements. Among species, the control region ranged from 942 to 971 bp in length. Our data were compatible with the proposal of three domains (extended terminal associated sequences [ETAS], central, conserved sequence blocks [CSB]) within the control region. The most conserved region in the control region was the central domain (12% of nucleotide positions variable), whereas in the ETAS and CSB domains, 22% and 40% of nucleotide positions were variable, respectively. Tandem repeats were encountered only in the ETAS domain of Clethrionomys rufocanus. This tandem repeat found in C. rufocanus was 24 bp in length and was located at the 5' end of the control region. Only two of the proposed CSB and ETAS elements appeared to be supported by our data; however, a "CSB1-like" element was also documented in the ETAS domain.

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    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.

  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

    2016-08-19

    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.

  15. The formation and build-up of the red-sequence over the past 9 Gyr in VIPERS

    NASA Astrophysics Data System (ADS)

    Fritz, Alexander; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bolzonella, M.; Bottini, D.; Branchini, E.; Burden, A.; Cappi, A.; Coupon, J.; Cucciati, O.; Davidzon, I.; De Lucia, G.; de la Torre, S.; Di Porto, C.; Franzetti, P.; Fumana, M.; Garilli, B.; Granett, B. R.; Guzzo, L.; Ilbert, O.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marchetti, A.; Marinoni, C.; Marulli, F.; McCracken, H. J.; Mellier, Y.; Moscardini, L.; Nichol, R. C.; Paioro, L.; Peacock, J. A.; Percival, W. J.; Polletta, M.; Pollo, A.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zamorani, G.; Zanichelli, A.; VIPERS Team

    2015-02-01

    We present the Luminosity Function (LF) and Colour-Magnitude Relation (CMR) using ~45000 galaxies drawn from the VIMOS Public Extragalactic Redshift Survey (VIPERS). Using different selection criteria, we define several samples of early-type galaxies and explore their impact on the evolution of the red-sequence (RS) and the effects of dust. Our results suggest a rapid build-up of the RS within a short time scale. We find a rise in the number density of early-type galaxies and a strong evolution in LF and CMR. Massive galaxies exist already 9 Gyr ago and experience an efficient quenching of their star formation at z = 1, followed by a passive evolution with only limited merging activity. In contrast, low-mass galaxies indicate a different mass assembly history and cause a slow build-up of the CMR over cosmic time.

  16. 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

  17. THE STAR FORMATION HISTORIES OF RED-SEQUENCE GALAXIES, MASS-TO-LIGHT RATIOS AND THE FUNDAMENTAL PLANE

    SciTech Connect

    Allanson, Steven P.; Hudson, Michael J.; Smith, Russell J.; Lucey, John R.

    2009-09-10

    This paper addresses the challenge of understanding the typical star formation histories of red-sequence galaxies, using linestrength indices and mass-to-light ratios as complementary constraints on their stellar age distribution. We first construct simple parametric models of the star formation history that bracket a range of scenarios, and fit these models to the linestrength indices of low-redshift cluster red-sequence galaxies. For giant galaxies, we confirm the downsizing trend, i.e., the stellar populations are younger, on average, for lower {sigma} galaxies. We find, however, that this trend flattens or reverses at {sigma} {approx}< 70 km s{sup -1}. We then compare predicted stellar mass-to-light ratios with dynamical mass-to-light ratios derived from the fundamental plane (FP), or by the SAURON group. For galaxies with {sigma} {approx} 70 km s{sup -1}, models with a late 'frosting' of young stars and models with exponential star formation histories have stellar mass-to-light ratios that are larger than observed dynamical mass-to-light ratios by factors of 1.7 and 1.4, respectively, and so are rejected. The single stellar population (SSP) model is consistent with the FP, and requires a modest amount of dark matter (between 20% and 30%) to account for the difference between stellar and dynamical mass-to-light ratios. A model in which star formation was 'quenched' at intermediate ages is also consistent with the observations, although in this case less dark matter is required for low mass galaxies. We also find that the contribution of stellar populations to the 'tilt' of the fundamental plane is highly dependent on the assumed star formation history: for the SSP model, the tilt of the FP is driven primarily by stellar-population effects. For a quenched model, two-thirds of the tilt is due to stellar populations and only one-third is due to dark matter or non-homology.

  18. Comprehensive analysis of expressed sequence tags from the pulp of the red mutant 'Cara Cara' navel orange (Citrus sinensis Osbeck).

    PubMed

    Ye, Jun-Li; Zhu, An-Dan; Tao, Neng-Guo; Xu, Qiang; Xu, Juan; Deng, Xiu-Xin

    2010-10-01

    Expressed sequence tag (EST) analysis of the pulp of the red-fleshed mutant 'Cara Cara' navel orange provided a starting point for gene discovery and transcriptome survey during citrus fruit maturation. Interpretation of the EST datasets revealed that the mutant pulp transcriptome held a high section of stress responses related genes, such as the type III metallothionein-like gene (6.0%), heat shock protein (2.8%), Cu/Zn superoxide dismutase (0.8%), late embryogenesis abundant protein 5 (0.8%), etc. 133 transcripts were detected to be differentially expressed between the red mutant and its orange-color wild genotype 'Washington' via digital expression analysis. Among them, genes involved in metabolism, defense/stress and signal transduction were statistical overrepresented. Fifteen transcription factors, composed of NAM, ATAF, and CUC transcription factor (NAC); myeloblastosis (MYB); myelocytomatosis (MYC); basic helix-loop-helix (bHLH); basic leucine zipper (bZIP) domain members, were also included. The data reflected the distinct expression profile and the unique regulatory module associated with these two genotypes. Eight differently expressed genes analyzed in digital were validated by quantitative real-time polymerase chain reaction. For structural polymorphism, both simple sequence repeats and single nucleotide polymorphisms (SNP) loci were surveyed; dinucleotide presentation revealed a bias toward AG/GA/TC/CT repeats (52.5%), against GC/CG repeats (0%). SNPs analysis found that transitions (73%) outnumbered transversions (27%). Seventeen potential cultivar-specific and 387 heterozygous SNP loci were detected from 'Cara Cara' and 'Washington' EST pool.

  19. 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.

  20. 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.

  1. 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

  2. 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

    2015-12-29

    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.

  3. Draft Genome Sequence of Francisella noatunensis subsp. orientalis STIR-GUS-F2f7, a Highly Virulent Strain Recovered from Diseased Red Nile Tilapia Farmed in Europe

    PubMed Central

    Larsson, Pär; Wehner, Stefanie; Bekaert, Michaël; Öhrman, Caroline; Metselaar, Matthijs; Thompson, Kimberly Dawn; Richards, Randolph Harvey; Penman, David James; Adams, Alexandra

    2017-01-01

    ABSTRACT A highly virulent strain of Francisella noatunensis subsp. orientalis, STIR-GUS-F2f7, was isolated from moribund red Nile tilapia (Oreochromis niloticus) farmed in Europe. In this communication, the complete genome sequencing of this bacterium is reported. PMID:28302784

  4. 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.

  5. 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

  6. Faint Submillimeter Galaxies Behind Lensing Clusters

    NASA Astrophysics Data System (ADS)

    Hsu, Li-Yen; Lauchlan Cowie, Lennox; Barger, Amy J.; Desai, Vandana; Murphy, Eric J.

    2017-01-01

    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. Observations of massive cluster fields are the best way to explore this faint submillimeter population, thanks to gravitational lensing effects. We have been undertaking a lensing cluster survey with the SCUBA-2 camera on the James Clerk Maxwell Telescope to map nine galaxy clusters, including the northern five clusters in the HST Frontier Fields program. We have also been using the Submillimeter Array and the Very Large Array to determine the accurate positions of our detected sources. Our observations have discovered high-redshift dusty galaxies with far-infrared luminosities similar to that of the Milky Way or luminous infrared galaxies. Some of these galaxies are still undetected in deep optical and near-infrared images. These results suggest that a substantial amount of star formation in even the faint submillimeter population may be hidden from rest-frame optical surveys.

  7. 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.

  8. Sequence polymorphism in the human melanocortin 1 receptor gene as an indicator of the red hair phenotype.

    PubMed

    Grimes, E A; Noake, P J; Dixon, L; Urquhart, A

    2001-11-01

    We describe a minisequencing protocol for screening DNA samples for the presence of 12 mutations in the human melanocortin 1 receptor gene (MC1R), eight of which are associated with the red hair phenotype. A minisequencing profile which shows homozygosity for one of these mutations or the presence of two different mutations would strongly indicate that the sample donor is red haired. The absence of any red hair causing mutations would indicate that the sample donor does not have red hair. We report the frequencies of MC1R variants in the British red haired population.

  9. Identification of sequence-related amplified polymorphism markers linked to the red leaf trait in ornamental kale (Brassica oleracea L. var. acephala).

    PubMed

    Wang, Y S; Liu, Z Y; Li, Y F; Zhang, Y; Yang, X F; Feng, H

    2013-04-02

    Artistic diversiform leaf color is an important agronomic trait that affects the market value of ornamental kale. In the present study, genetic analysis showed that a single-dominant gene, Re (red leaf), determines the red leaf trait in ornamental kale. An F2 population consisting of 500 individuals from the cross of a red leaf double-haploid line 'D05' with a white leaf double-haploid line 'D10' was analyzed for the red leaf trait. By combining bulked segregant analysis and sequence-related amplified polymorphism technology, we identified 3 markers linked to the Re/re locus. A genetic map of the Re locus was constructed using these sequence-related amplified polymorphism markers. Two of the markers, Me8Em4 and Me8Em17, were located on one side of Re/re at distances of 2.2 and 6.4 cM, whereas the other marker, Me9Em11, was located on the other side of Re/re at a distance of 3.7 cM. These markers could be helpful for the subsequent cloning of the red trait gene and marker-assisted selection in ornamental kale breeding programs.

  10. 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.

  11. 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

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

    PubMed

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

    2015-06-29

    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.

  13. 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.

  14. 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.

  15. Employment of bromophenol red and bovine serum albumin as luminol signal co-enhancer in chemiluminescent detection of sequence-specific DNA.

    PubMed

    Yu, Xiaoqian; Sheng, Yingying; Zhao, Yanjun; Fan, Aiping

    2016-01-01

    Bromophenol red, known as chemical indicator, was found to act as a novel potent signal enhancer of the peroxidase-catalyzed luminol-H2O2 chemiluminescent (CL) reaction. It was found interestingly that bovine serum albumin (BSA) played a role in the enhanced chemiluminescent reaction (ECR). The addition of 2.5 mg mL(-1) BSA into bromophenol red-enhance CL system showed 36 times stronger CL signal than that without addition of BSA. Mechanism study showed that the luminophors in the ECR were still 3-aminophthalate ion in an excited state (3-APA*). In addition, singlet oxygen ((1)O2) and hydroxyl radical ((∙)OH) played a role in the ECR. The possible mechanism was discussed in the present study. The effect of pH, reaction time, and concentration of bromophenol red, BSA, luminol, and H2O2 on CL intensity of the peroxidase-catalyzed CL reaction was studied. The detection limit value (LOD) of HRP and streptavidin-modified HRP in the proposed ECR with bromophenol red and BSA was 0.20 ng mL(-1) and 0.05 ng mL(-1), respectively. This novel luminol-H2O2-HRP-bromophenol red-BSA CL system was applied to the CL detection of sequence-specific DNA based on a magnetic separation process. As low as 0.4 fmol of target DNA could be sensitively detected using the proposed CL system without any amplification process. The obtained results demonstrate very promising perspectives for using bromophenol red and BSA to improve the sensitivity of CL detection of sequence-specific DNA. In addition, this novel ECR system can also be generalized for CL immunoassay, CL western blotting, and so on.

  16. 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.

  17. SMASH 1: A Very Faint Globular Cluster Disrupting in the Outer Reaches of the LMC?

    NASA Astrophysics Data System (ADS)

    Martin, Nicolas F.; Jungbluth, Valentin; Nidever, David L.; Bell, Eric F.; Besla, Gurtina; Blum, Robert D.; Cioni, Maria-Rosa L.; Conn, Blair C.; Kaleida, Catherine C.; Gallart, Carme; Jin, Shoko; Majewski, Steven R.; Martinez-Delgado, David; Monachesi, Antonela; Muñoz, Ricardo R.; Noël, Noelia E. D.; Olsen, Knut; Stringfellow, Guy S.; van der Marel, Roeland P.; Vivas, A. Katherina; Walker, Alistair R.; Zaritsky, Dennis

    2016-10-01

    We present the discovery of a very faint stellar system, SMASH 1, that is potentially a satellite of the Large Magellanic Cloud. Found within the Survey of the Magellanic Stellar History (SMASH), SMASH 1 is a compact ({r}h={9.1}-3.4+5.9 {pc}) and very low luminosity ({M}V=-1.0+/- 0.9, {L}V={10}2.3+/- 0.4 {L}⊙ ) stellar system that is revealed by its sparsely populated main sequence and a handful of red giant branch candidate member stars. The photometric properties of these stars are compatible with a metal-poor ([{Fe}/{{H}}]=-2.2) and old (13 Gyr) isochrone located at a distance modulus of ˜18.8, i.e., a distance of ˜ 57 {kpc}. Situated at 11.°3 from the LMC in projection, its three-dimensional distance from the Cloud is ˜ 13 {kpc}, consistent with a connection to the LMC, whose tidal radius is at least 16 {kpc}. Although the nature of SMASH 1 remains uncertain, its compactness favors it being a stellar cluster and hence dark-matter free. If this is the case, its dynamical tidal radius is only ≲ 19 {pc} at this distance from the LMC, and smaller than the system’s extent on the sky. Its low luminosity and apparent high ellipticity (ɛ ={0.62}-0.21+0.17) with its major axis pointing toward the LMC may well be the tell-tale sign of its imminent tidal demise.

  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. Complete genome sequence of Coriobacterium glomerans type strain (PW2(T)) from the midgut of Pyrrhocoris apterus L. (red soldier bug).

    PubMed

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

    2013-04-15

    Coriobacterium glomerans Haas and König 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 PW2(T) 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 G enomic E ncyclopedia of Bacteria and Archaea project.

  20. The mitochondrial genome of the red alga Kappaphycus striatus ("Green Sacol" variety): complete nucleotide sequence, genome structure and organization, and comparative analysis.

    PubMed

    Tablizo, Francis A; Lluisma, Arturo O

    2014-12-01

    The complete mitochondrial (mt) DNA sequence of the rhodophyte Kappaphycus striatus ("Green Sacol" variety) was determined. The mtDNA is circular, 25,242 bases long (A+T content: 69.94%), and contains 50 densely packed genes comprising 93.22% of the mitochondrial genome, with genes encoded on both strands. Through comparative analysis, the overall sequence, genome structure, and organization of K. striatus mtDNA were seen to be highly similar with other fully sequenced mitochondrial genomes of the class Florideophyceae. On the other hand, certain degrees of genome rearrangements and greater sequence dissimilarities were observed for the mtDNAs of other evolutionarily distant red algae, such as those from the class Bangiophyceae and Cyanidiophyceae, compared to that of K. striatus. Furthermore, a trend was observed wherein the red algal mtDNAs tend to encode lesser number of protein-coding genes, albeit not necessarily shorter, as the organism becomes more morphologically complex. This trend is supported by the phylogenetic tree inferred from the concatenated amino acid sequences of the deduced protein products of cytochrome c oxidase subunit genes (cox1, 2, and 3).

  1. Novel sequence types of Chlamydia pecorum infect free-ranging Alpine ibex (Capra ibex) and red deer (Cervus elaphus) in Switzerland.

    PubMed

    Jelocnik, Martina; Self, Rachel; Timms, Peter; Borel, Nicole; Polkinghorne, Adam

    2015-04-01

    Chlamydia pecorum, a recognized pathogen of domesticated ruminants and koalas (Phascolarctos cinereus), has been recently reported in a broad range of other wildlife species including water buffalo (Bubalus bubalis), ibex (Capra ibex), chamois (Rupicapra rupicapra), red deer (Cervus elaphus), and birds. This identification raises questions as to whether cross-host transmission may be a factor in the epidemiology of infections in these species. To begin to address this question, we employed a C. pecorum species-specific multi-locus sequence typing (MLST) scheme to characterize a small collection of C. pecorum-positive samples from wild, free-range ibex, a chamois, and a red deer from Grison, Switzerland, a canton where domesticated and wild ruminants graze in close proximity during the summer. Screening by PCR confirmed low to moderate levels of Chlamydia pecorum DNA in the eyes of healthy ibex (n = 4) and in the deer fecal sample (n = 1). The MLST analysis revealed three novel sequence types (STs; 88, 90, and 89) in these samples. On phylogenetic analysis, the ibex and deer sequences clustered by host species in their own well-supported clades and away from C. pecorum STs found in other hosts. Even though the analyzed sample size was small, the identification of unique C. pecorum STs infecting free-ranging Alpine ibex and red deer provides useful information for further C. pecorum epidemiologic studies.

  2. SUPERNOVA 2003ie WAS LIKELY A FAINT TYPE IIP EVENT

    SciTech Connect

    Arcavi, Iair; Gal-Yam, Avishay; Sergeev, Sergey G.

    2013-04-15

    We present new photometric observations of supernova (SN) 2003ie starting one month before discovery, obtained serendipitously while observing its host galaxy. With only a weak upper limit derived on the mass of its progenitor (<25 M{sub Sun }) from previous pre-explosion studies, this event could be a potential exception to the ''red supergiant (RSG) problem'' (the lack of high-mass RSGs exploding as Type IIP SNe). However, this is true only if SN2003ie was a Type IIP event, something which has never been determined. Using recently derived core-collapse SN light-curve templates, as well as by comparison to other known SNe, we find that SN2003ie was indeed a likely Type IIP event. However, with a plateau magnitude of {approx} - 15.5 mag, it is found to be a member of the faint Type IIP class. Previous members of this class have been shown to arise from relatively low-mass progenitors (<12 M{sub Sun }). It therefore seems unlikely that this SN had a massive RSG progenitor. The use of core-collapse SN light-curve templates is shown to be helpful in classifying SNe with sparse coverage. These templates are likely to become more robust as large homogeneous samples of core-collapse events are collected.

  3. 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.

  4. 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.

  5. Faint radio sources and gravitational lensing

    SciTech Connect

    Langston, G.I.; Conner, S.R.; Heflin, M.B.; Lehar, J.; Burke, B.F. MIT, Cambridge, MA )

    1990-04-01

    Measurements of the surface density of radio sources resulting from a deep VLA integration at 5 GHz and the MIT-Green Bank (MG) II 5 GHz survey are summarized. The faint source counts are combined with previous observations and fitted to a power-law function of surface density vs. limiting flux density. The surface density of radio sources brighter than 1 mJy is k = 0.019 + or - 0.004/arcmin. The power-law exponent is best fit by -0.93 + or - 0.14. Between 15 and 100 mJy, the surface density of radio sources varies nearly as predicted by Euclidian models of the universe. Estimates are given for the number of chance alignments of radio sources in the VLA snapshot observations of the MIT-Princeton-Caltech gravitational lens search. The probability of lens candidate configurations occurring by chance alignment is calculated. 28 refs.

  6. 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.

  7. LoCuSS: exploring the selection of faint blue background galaxies for cluster weak-lensing

    NASA Astrophysics Data System (ADS)

    Ziparo, Felicia; Smith, Graham P.; Okabe, Nobuhiro; Haines, Chris P.; Pereira, Maria J.; Egami, Eiichi

    2016-12-01

    Cosmological constraints from galaxy clusters rely on accurate measurements of the mass and internal structure of clusters. An important source of systematic uncertainty in cluster mass and structure measurements is the secure selection of background galaxies that are gravitationally lensed by clusters. This issue has been shown to be particular severe for faint blue galaxies. We therefore explore the selection of faint blue background galaxies, by reference to photometric redshift catalogues derived from the Cosmological Evolution Survey (COSMOS) and our own observations of massive galaxy clusters at z ≃ 0.2. We show that methods relying on photometric redshifts of galaxies in/behind clusters based on observations through five filters, and on deep 30-band COSMOS photometric redshifts are both inadequate to identify safely faint blue background galaxies with the same 1 per cent contamination level that we have achieved with red galaxies. This is due to the small number of filters used by the former, and absence of massive galaxy clusters at redshifts of interest in the latter. Nevertheless, our least contaminated blue galaxy sample yields stacked weak-lensing results consistent with our previously published results based on red galaxies, and we show that the stacked clustercentric number density profile of these faint blue galaxies is consistent with expectations from consideration of the lens magnification signal of the clusters. Indeed, the observed number density of blue background galaxies changes by ˜10-30 per cent across the radial range over which other surveys assume it to be flat.

  8. 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.

  9. 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.

  10. Polarizer mechanism for the space telescope faint object spectrograph

    NASA Technical Reports Server (NTRS)

    Thulson, M. D.

    1983-01-01

    The polarizer mechanism for the Space Telescope Faint Object Spectrograph is described. This device will allow spectropolarimetric measurements of faint astronomical objects. The mechanism employs a unique arrangement to meet functional requirements in a compact package and with only one actuator. Detailed tolerance analysis and a variety of tests indicate that the polarizer is capable of accurate and reliable performance.

  11. 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.

  12. 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.

  13. 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

  14. Hot Young Solution to Faint Sun Paradox

    NASA Astrophysics Data System (ADS)

    Riofrio, L.

    2006-12-01

    The "Faint Young Sun" has been a paradox of astrophysics. The standard solar model predicts that 4 billion years ago Earth was too cold to support life. Geology and the fossil record contradict this prediction. The paradox and possible solution are a fascinating combination of astrophysics, relativity and the Earth sciences. Models predict that 4 billion years ago the Sun shone with only 70 % of its present luminosity. Since power P is related to temperature T by the Stefan-Boltzmann Law P ∝ T4, Earth temperature would have been only 91 % of its present value. That temperature is approximately 283K, so temperature in the past would have been only 258K. Earth's surface would have frozen solid, making evolution of life very unlikely. Geology shows evidence of extensive sedimentation 4 billion years ago. Other geological markers corroborate the presence of liquid water on Earth during this period. Paleontology dates the earliest organisms at least 3.4 to 4 billion years old. Clearly liquid water and life both existed when the model predicts Earth was frozen solid. This conflict with observations is the Faint Young Sun paradox. Fortunately, Relativity and Space/Time can help save the standard solar model. The Sun converts its fuel to energy according to E=mc2. Unified Space/Time predicts that c is given by: GM=tc3. Where t is age of the Universe, GM combines its mass and gravitational constant. Solving, we have c(t)=(GM)^{1/3} t^{-1/3}. Billions of years ago, solar output and temperature were therefore higher than originally calculated. Earth is estimated to be 4.6 billion years and the Universe 13.7 billion years old, 1.5 times its age at the time of Earth's formation. Energy e=mc2 is adjusted by (1.5)^{2/3} = 1.31 times the initial estimate. Multiplying by that estimate of 70 %, the Sun's actual output was 0.917 of the present value. Temperature was then (0.917)^{1/4} = 98 % of today's value. If we start with an estimate of 76 %, the Sun's true output was exactly

  15. 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

  16. Faint high-latitude carbon stars

    NASA Astrophysics Data System (ADS)

    Green, Paul Jonathan

    We have undertaken a wide area survey to search for faint high latitude carbon (FHLC) stars. Carbon giants are ideal for study of the structure and kinematics of the outer galactic halo. We use two color photometric selection with large format charge-coupled devices (CCD's) to cover 52 deg2 of sky to a depth of about V = 18. Below this limit, we find good (approximately less than 20 percent) agreement between our object counts as a function of magnitude and the galactic models of Bahcall and Soneira at a variety of latitudes and longitudes. Our spectroscopic followup began with low-resolution spectra of 19 unconfirmed C star candidates from the Case objective-prism photographic survey of Sanduleak and Pesch. Four of these we find to be M stars. The 15 C stars we classify on the two-parameter Keenan-Morgan system as warm (color class less than 3). Of 94 faint C star candidates from our own CCD survey, one highly ranked V = 17 candidate was found to have strong carbon and CN bands. We estimate that to a depth of V = 18, the surface density FHLC stars is 0.019+0.044-.016 deg-2. We identify two FHLC stars with previously catalogued high proper motion objects. These objects are thus inferred to be dwarf carbon (dC) stars, supplementing the one previously known case, G77-61. Not all dC stars will have detectable proper motions, so other luminosity/distance indicators are needed: we find that C dwarfs all have similar JHK colors, and possibly an unusually strong lambda-6191 bandhead of carbon. By comparing positions in the HST Guide Star Catalog and the original Palomar Observatory Sky Survey, we detect proper motions in two additional FHLC stars. Our proper motion survey, spanning a 30 year baseline, thus identifies two new dC's, and provides proper motion upper limits for another 44 FHLC stars. Kinematic simulations suggest that virtually all Population 2 dC's will have detectable proper motions in a survey as sensitive as our own, and that to a limit of V approximately

  17. Faint High-Latitude Carbon Stars

    NASA Astrophysics Data System (ADS)

    Green, Paul J.

    1992-10-01

    Since carbon giants are ideal for study of the structure and kinematics of the outer galactic halo, we have undertaken a wide-area survey to search for faint high-latitude carbon (FHLC) stars. We use two-color photometric selection with large format CCDs to cover 52 deg^2 of sky to a depth of about V=18. Below this limit, we find good (< 20%) agreement between our object counts as a function of magnitude and the galactic models of Bahcall and Coneira (1984) at a variety of latitudes and longitudes. Our spectroscopic followup began with low-resolution spectra of 19 unconfirmed C-star candidates from the Case objective-prism photographic survey of Sanduleak and Pesch (1988). Four of these we find to be M stars. The 15 C stars we classify on the two-parameter Keenan-Morgan (1941) system as warm (color class < 4), with moderate to weak carbon band strengths (C class < 3). Of 94 faint C-star candidates from our own CCD survey, one highly ranked V=17 candidate was found to have strong carbon and CN bands. We estimate that to a depth of V=18, the surface density of FHLC stars is 0.019^0.044_-0.016 deg^-2. We identify two FHLC stars with previously cataloged high-proper-motion objects. These objects are thus inferred to be dwarf carbon (dC) stars, supplementing the one previously known case, G 77-61. Not all dC stars will have detectable proper motions, so other luminosity/distance indicators are needed: we find that C dwarfs all have similar JHK colors, and possibly an unusually strong lambda-6191 bandhead of carbon. By comparing positions of the HST Guide Star Catalog and the original Palomar Observatory Sky Survey, we detect proper motions in two additional FHLC stars. Our proper-motion survey, spanning a 30-yr base line, thus identifies four new dC's, and provides proper-motion upper limits for another 44 FHLC stars. Kinematic simulations suggest that virtually all Population II dCs will have detectable proper motions in a survey as sensitive as our own, and that to a

  18. 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.

  19. 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.

  20. The Population of Optically Faint GEO Debris

    NASA Astrophysics Data System (ADS)

    Seitzer, P.; Barker, E.; Buckalew, B.; Burkhardt, A.; Cowardin, H.; Frith, J.; Kaleida, C.; Lederer, S.; Lee, C.

    2016-09-01

    The 6.5-m Magellan telescope, 'Walter Baade', at the Las Campanas Observatory in Chile has been used for spot surveys of the geosynchronous Earth orbit (GEO) regime to study the population of optically faint GEO debris. The goal is to estimate the population of GEO debris at sizes much smaller than can be studied with 1-meter class telescopes. Despite the small field of view of the Magellan instrument (diameter 0.5-degree), a significant population of objects fainter than R = 19th magnitude has 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 detections have a wide range of characteristics starting with those appearing as short uniform streaks. But there are a substantial number of detections that vary 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 product of size * albedo. If the albedo is of the order of 0.2, then the largest projected size of these objects is around 10-cm.

  1. 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.

  2. Optically faint radio sources: reborn AGN?

    NASA Astrophysics Data System (ADS)

    Filho, M. E.; Brinchmann, J.; Lobo, C.; Antón, S.

    2011-12-01

    We present our discovery of several relatively strong radio sources in the field-of-view of SDSS galaxy clusters that have no optical counterparts down to the magnitude limits of the SDSS. The optically faint radio sources appear as double-lobed or core-jet objects in the FIRST radio images and have projected angular sizes ranging from 0.5 to 1.0 arcmin. We followed-up these sources with near-infrared imaging using the wide-field imager HAWK-I on the VLT. We detected Ks-band emitting regions, about 1.5 arcsec in size and coincident with the centers of the radio structures, in all sources, with magnitudes in the range 17-20 mag. We used spectral modelling to characterize the sample sources. In general, the radio properties are similar to those observed in 3CRR sources but the optical-radio slopes are consistent with those of moderate to high redshift (z < 4) gigahertz-peaked spectrum sources. Our results suggest that these unusual objects are galaxies whose black hole has been recently re-ignited but that retain large-scale radio structures, which are signatures of previous AGN activity.

  3. 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

    2015-12-04

    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.

  4. 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

  5. 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.

  6. Faint spatial object classifier construction based on data mining technology

    NASA Astrophysics Data System (ADS)

    Lou, Xin; Zhao, Yang; Liao, Yurong; Nie, Yong-ming

    2016-11-01

    Data mining can effectively obtain the faint spatial object's patterns and characteristics, the universal relations and other implicated data characteristics, the key of which is classifier construction. Faint spatial object classifier construction with spatial data mining technology for faint spatial target detection is proposed based on theoretical analysis of design procedures and guidelines in detail. For the one-sidedness weakness during dealing with the fuzziness and randomness using this method, cloud modal classifier is proposed. Simulating analyzing results indicate that this method can realize classification quickly through feature combination and effectively resolve the one-sidedness weakness problem.

  7. 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.

  8. 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.

  9. Use of simple sequence repeat markers for DNA fingerprinting and diversity analysis of sugarcane (Saccharum spp) cultivars resistant and susceptible to red rot.

    PubMed

    Hameed, U; Pan, Y-B; Muhammad, K; Afghan, S; Iqbal, J

    2012-05-08

    Red rod is an economically important disease of sugarcane caused by the fungus Colletotrichum falcatum. We used a simple sequence repeat (SSR)-based marker system to identify and analyze genetic relationships of red rot resistant and susceptible sugarcane cultivars grown in Pakistan. Twenty-one highly polymorphic SSR markers were used for DNA fingerprinting and genetic diversity analysis of 20 sugarcane cultivars. These SSR markers were found to be highly robust; we identified 144 alleles, with 3-11 alleles per marker and a mean of 6.8. Three SSR markers were able to identify all 20 cultivars. DNAMAN(®)-generated homology tree was used to analyze genetic diversity among these cultivars; all cultivars shared 58% or more similarity. We correlated polymorphism information content and resolving power values with marker effectiveness in the process of sugarcane cultivar identification. We concluded that a small number of SSR-derived DNA markers will allow breeders to identify red rot resistant and susceptible cultivars.

  10. Predicting the fate of binary red giants using the observed sequence E star population: binary planetary nebula nuclei and post-RGB stars

    NASA Astrophysics Data System (ADS)

    Nie, J. D.; Wood, P. R.; Nicholls, C. P.

    2012-07-01

    Sequence E variables are close binary red giants that show ellipsoidal light variations. They are likely the immediate precursors of planetary nebulae (PNe) with close binary central stars as well as other binary post-asymptotic giant branch (post-AGB) and binary post-red giant branch (post-RGB) stars. We have made a Monte Carlo simulation to determine the fraction of red giant binaries that go through a common envelope event leading to the production of a close binary system or a merged star. The novel aspect of this simulation is that we use the observed frequency of sequence E binaries in the Large Magellanic Cloud (LMC) to normalize our calculations. This normalization allows us to produce predictions that are relatively independent of model assumptions. In our standard model, and assuming that the relative numbers of PNe of various types are proportional to their birth rates, we find that in the LMC today the fraction of PNe with close binary central stars is 7-9 per cent, the fraction of PNe with intermediate period binary central stars having separations capable of influencing the nebula shape (orbital periods less than 500 yr) is 23-27 per cent, the fraction of PNe containing wide binaries that are unable to influence the nebula shape (orbital period greater than 500 yr) is 46-55 per cent, the fraction of PNe derived from single stars is 3-19 per cent, and 5-6 per cent of PNe are produced by previously merged stars. We also predict that the birth rate of post-RGB stars is ˜4 per cent of the total PN birth rate, equivalent to ˜50 per cent of the production rate of PNe with close binary central stars. These post-RGB stars most likely appear initially as luminous low-mass helium white dwarf binaries. The average lifetime of sequence E ellipsoidal variability with amplitude more than 0.02 mag is predicted to be ˜0.95 Myr. We use our model and the observed number of red giant stars in the top one magnitude of the RGB in the LMC to predict the number of PNe in

  11. 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.

  12. 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.

  13. 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,...

  14. Uncloned expanded CAG/CTG repeat sequences in autosomal dominant cerebellar ataxia (ADCA) detected by the repeat expansion detection (RED) method.

    PubMed Central

    Pujana, M A; Volpini, V; Gratacós, M; Corral, J; Banchs, I; Sánchez, A; Genís, D; Cervera, C; Estivill, X

    1998-01-01

    In some neurodegenerative diseases, genetic anticipation correlates with expansions of the CAG/CTG repeat sequence above the normal range through the generations of a pedigree. Among these neurodegenerative diseases are late onset autosomal dominant cerebellar ataxias (ADCA). ADCA are genetically heterogeneous disorders with different cloned genes for spinocerebellar ataxia type 1 (SCA1), type 2 (SCA2), type 3 or Machado-Joseph disease (SCA3/MJD), and type 6 (SCA6). Another related dominant ataxia, dentatorubral-pallidoluysian atrophy (DRPLA), also shows CAG/CTG repeat expansions. Genetic anticipation has been reported for all of them except for the recently cloned SCA6 gene. Other, as yet undetected SCA genes may show the same features. We have used the repeat expansion detection (RED) method to detect repeat expansions directly in DNA samples from ADCA patients not resulting from known genes. Our sample consists of 19 affected index cases, corresponding to 52.8% of our ADCA families without CAG/CTG repeat expansions in the SCA1, SCA2, SCA3/MJD, SCA6, or DRPLA genes. Eighty-nine percent of the index cases had expansions of a CAG/CTG sequence greater than 40 repeats by RED, while these were observed in only 26.9% of 78 healthy subjects from the general population (p < 0.0001). The distribution of RED fragments in controls and ADCA patients also shows significant differences with the Mann-Whitney U test (U = 376.5, p = 0.0007). Moreover, there was a significant inverse correlation between the size of expansion and the age of onset (r = -0.54, p = 0.018). These results show CAG/CTG repeat expansions of over 40 repeats in our sample of ADCA families not resulting from known SCA genes. Images PMID:9507387

  15. 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

  16. Phenolic compositions of 50 and 30 year sequences of Australian red wines: the impact of wine age.

    PubMed

    McRae, Jacqui M; Dambergs, Robert G; Kassara, Stella; Parker, Mango; Jeffery, David W; Herderich, Markus J; Smith, Paul A

    2012-10-10

    The phenolic composition of red wine impacts upon the color and mouthfeel and thus quality of the wine. Both of these characteristics differ depending on the age of a wine, with the purple of young wines changing to brick red and the puckering or aggressive astringency softening in older wines. This study investigated the color parameters, tannin concentrations and tannin composition of a 50 year series of Cabernet Sauvignon wines from a commercial label as well as 30 year series of Cabernet Sauvignon and Shiraz wines from a separate commercial label to assess the impact of wine age on phenolic composition and concentration. The wine color density in wines of 40 to 50 years old was around 5 AU compared with 16 AU of wine less than 12 months old, which correlated well with the concentration of non-bleachable pigments and pigmented polymers. Conversely, the anthocyanin concentrations in 10 year old wines were substantially lower than that of recently bottled wines (around 100 mg/L compared with 627 mg/L, respectively), adding further evidence that non-bleachable pigments including pigmented polymers play a much larger role in long-term wine color than anthocyanins. No age-related trend was observed for tannin concentration, indicating that the widely noted softer astringency of older red wines cannot necessarily be directly related to lower concentrations of soluble wine tannin and is potentially a consequence of changes in tannin structure. Wine tannins from older wines were generally larger than tannins from younger wines and showed structural changes consistent with oxidation.

  17. The morphology of faint galaxies in Medium Deep Survey images using WFPC2

    NASA Technical Reports Server (NTRS)

    Griffiths, R. E.; Casertano, S.; Ratnatunga, K. U.; Neuschaefer, L. W.; Ellis, R. S.; Gilmore, G. F.; Glazebrook, K.; Santiago, B.; Huchra, J. P.; Windhorst, R. A.

    1994-01-01

    First results from Hubble Space Telescope (HST) Medium Deep Survey images taken with Wide Field/Planetary Camera-2 (WFPC2) demonstrate that galaxy classifications can be reliably performed to magnitudes I814 approximately less than 22.0 in the F815W band. Published spectroscopic surveys to this depth indicate a mean redshift of bar-z approximately 0.5. We have classified over 200 galaxies in nine WFPC2 fields according to a basic morphological scheme. The majority of these faint galaxies appear to be similar to regular Hubble-sequence examples observed at low redshift. To the precision of our classification scheme, the relative proportion of spheroidal and disk systems of normal appearance is as expected from nearby samples, indicating that the bulk of the local galaxy population was in place at half the Hubble time. However, the most intriguing result is the relatively high proportion (approximately 40%) of objects which are in some way anomalous, and which may be of relevance in understanding the origin of the familiar excess population of faint galaxies established by others. These diverse objects include apparently interacting pairs whose multiple structure is only revealed with HST's angular resolution, galaxies with superluminous star-forming regions, diffuse low surface brightness galaxies of various forms, and compact galaxies. These anomalous galaxies contribute a substantial fraction of the excess counts at our limiting magnitude, and may provide insights into the 'faint blue galaxy' problem.

  18. HST observations of faint Cold Classical KBOs

    NASA Astrophysics Data System (ADS)

    Penteado, Paulo F.; Trilling, David E.; Grundy, Will

    2016-10-01

    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, 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 KBOs, 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 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.We obtained HST observations of 16 faint Cold Classicals, which we combine with archival HST observations of 20 others, to examine the distribution of two properties of the smallest KBOs: colors and binary fraction. These 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. Another 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.We present the constraints to the color and binary

  19. Genome Sequences of Strain ATCC 29281 and Pin and Northern Red Oak Isolates of Lonsdalea quercina subsp. quercina

    PubMed Central

    Ibarra Caballero, Jorge; Zerillo, Marcelo M.; Snelling, Jacob; Cranshaw, Whitney; Boucher, Christina

    2014-01-01

    Two bacteria identified as Lonsdalea quercina subsp. quercina were isolated from oak trees showing symptoms of drippy blight. Here, we present their draft genome assemblies, as well as that of the type strain of this species. To our knowledge, these are the first published genome sequences of this subspecies of Lonsdalea quercina. PMID:24926062

  20. Draft Genome Sequence of Oenococcus oeni Strain X2L (CRL1947), Isolated from Red Wine of Northwest Argentina

    PubMed Central

    Saavedra, Lucila

    2015-01-01

    We report the draft genome sequence of Oenococcus oeni strain X2L, a potential starter culture of malolactic fermentation, isolated from Malbec wine of Argentina. Genes encoding for enzymes involved in the metabolism of malate, citrate, and nitrogen compounds, as well as aroma compounds, were found in this genome, showing its ability to improve the sensorial characteristics of wines. PMID:25555740

  1. Complete mitogenome sequences of the pacific red snapper (Lutjanus peru) and the spotted rose snapper (Lutjanus gutattus).

    PubMed

    Bayona-Vásquez, Natalia Juliana; Hernández-Álvarez, Cristóbal Alejandro; Glenn, Travis; Domínguez-Domínguez, Omar; Uribe-Alcocer, Manuel; Díaz-Jaimes, Píndaro

    2017-03-01

    The structure of the mitochondrial genome for the Pacific red snapper, Lutjanus peru, and the spotted rose snapper, Lutjanus gutattus, of specimens collected in the eastern Pacific is similar to the reported for other teleosts and shares the same configuration with other members of the family Lutjanidae. It has a total length of 16 502 and 16 508 base pairs (bp) for Lutjanus peru and L. gutattus, respectively; on average the base composition was A (27.9%), T (24.8%) C (30.9%), and G (16.4%), containing 13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes; and the leucine (Leu) tRNA is duplicated.

  2. Kinematics and chemistry of faint high latitude dwarf carbon stars

    NASA Astrophysics Data System (ADS)

    Yoon, Jinmi; Beers, Timothy C.; Dietz, Sarah; Lee, Young Sun; Placco, Vinicius M.

    2017-01-01

    The diffuse halo system of the Milky Way is complex, and has been shown to comprise at least two main components: a near-zero net rotation inner-halo and a more rapidly rotating outer-halo component. Studies of the ancient, very metal-poor stars in the Galactic halo system are crucial for understanding its early formation history. The so-called carbon-enhanced metal-poor (CEMP) stars are an important subset of the stars in the halo system, which exhibit distinctive kinematic and chemical signatures that can be used to constrain the star-formation histories and assembly of the various Galactic components.We have examined the sample of main-sequence dwarf and other faint high Galactic latitude carbon-enhanced stars from the Sloan Digital Sky Survey studied by Green (2013). As noted by Green, many of these starsexhibit high proper motions, which have been later claimed to be related to possible binary ejection models Plant et al. (2016). By use of the CEMP sub-classification approach of Yoon et al. (2016), we investigate whether the kinematics of these stars might instead result from their membership in the inner/outer halo populations of the Galaxy.ReferencesGreen, P. 2013, ApJ, 765, 12Plant, K. et al. 2016, AAS 227.34115Yoon, J. et al. 2016, ApJ, in pressAcknowledgementThis work was supported in part by the National Science Foundation under Grant No. PHY-1430152 (JINA Center for the Evolution of the Elements).

  3. Characterizing elusive, faint dusty star-forming galaxies: a lensed, optically undetected ALMA galaxy at z 3.3

    NASA Astrophysics Data System (ADS)

    Santini, P.; Castellano, M.; Fontana, A.; Merlin, E.; Maiolino, R.; Mason, C.; Mignano, A.; Pilo, S.; Amorin, R.; Berta, S.; Bourne, N.; Calura, F.; Daddi, E.; Elbaz, D.; Grazian, A.; Magliocchetti, M.; Michałowski, M. J.; Pentericci, L.; Pozzi, F.; Rodighiero, G.; Schreiber, C.; Valiante, R.

    2016-12-01

    We present the serendipitous ALMA detection of a faint submillimeter galaxy (SMG) lensed by a foreground z 1 galaxy. By optimizing the source detection to deblend the system, we accurately build the full spectral energy distribution of the distant galaxy from the I814 band to radio wavelengths. It is extremely red, with a I-K colour larger than 2.5. We estimate a photometric redshift of 3.28 and determine the physical parameters. The distant galaxy turns out to be magnified by the foreground lens by a factor of 1.5, which implies an intrinsic Ks-band magnitude of 24.5, a submillimeter flux at 870 μm of 2.5 mJy and a SFR of 150-300 M⊙/ yr, depending on the adopted tracer. These values place our source towards the faint end of the distribution of observed SMGs, and in particular among the still few faint SMGs with a fully characterized spectral energy distribution, which allows us not only to accurately estimate its redshift, but also to measure its stellar mass and other physical properties. The galaxy studied in this work is a representative of the population of faint SMGs, of which only few objects are known to date, that are undetected in optical and therefore are not typically accounted for when measuring the cosmic star formation history (SFH). This faint galaxy population thus likely represents an important and missing piece in our understanding of the cosmic SFH. Its observation and characterization is of major importance to achieve a solid picture of galaxy evolution.

  4. Seismic strain tensor in the area to the South of Ras Mohamed region during the November-December, 2012 seismic sequence, Northern Red Sea, Egypt

    NASA Astrophysics Data System (ADS)

    Mohamed, Gad-Elkareem A.; Abd Allah, Saud A.

    2014-06-01

    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).

  5. 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).

  6. Galaxy Populations in Massive Galaxy Clusters to z = 1.1: Color Distribution, Concentration, Halo Occupation Number and Red Sequence Fraction

    NASA Astrophysics Data System (ADS)

    Hennig, C.; Mohr, J. J.; Zenteno, A.; Desai, S.; Dietrich, J. P.; Bocquet, S.; Strazzullo, V.; Saro, A.; Abbott, T. M. C.; Abdalla, F. B.; Bayliss, M.; Benoit-Lévy, A.; Bernstein, R. A.; Bertin, E.; Brooks, D.; Capasso, R.; Capozzi, D.; Carnero, A.; Kind, M. Carrasco; Carretero, J.; Chiu, I.; D'Andrea, C. B.; daCosta, L. N.; Diehl, H. T.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Fausti-Neto, A.; Fosalba, P.; Frieman, J.; Gangkofner, C.; Gonzalez, A.; Gruen, D.; Gruendl, R. A.; Gupta, N.; Gutierrez, G.; Honscheid, K.; Hlavacek-Larrondo, J.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; March, M.; Marshall, J. L.; Martini, P.; McDonald, M.; Melchior, P.; Miller, C. J.; Miquel, R.; Neilsen, E.; Nord, B.; Ogando, R.; Plazas, A. A.; Reichardt, C.; Romer, A. K.; Rozo, E.; Rykoff, E. S.; Sanchez, E.; Santiago, B.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Stalder, B.; Stanford, S. A.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.; Zhang, Y.

    2017-01-01

    We study the galaxy populations in 74 Sunyaev Zeldovich Effect (SZE) selected clusters from the South Pole Telescope (SPT) survey that have been imaged in the science verification phase of the Dark Energy Survey (DES). The sample extends up to z ˜ 1.1 with 4 × 1014M⊙ ≤ M200 ≤ 3 × 1015M⊙. Using the band containing the 4000 Å break and its redward neighbor, we study the color-magnitude distributions of cluster galaxies to ˜m★ + 2, finding: (1) the intrinsic rest frame g - r color width of the red sequence (RS) population is ˜0.03 out to z ˜ 0.85 with a preference for an increase to ˜0.07 at z = 1 and (2) the prominence of the RS declines beyond z ˜ 0.6. The spatial distribution of cluster galaxies is well described by the NFW profile out to 4R200 with a concentration of cg = 3.59^{+0.20}_{-0.18}, 5.37^{+0.27}_{-0.24} and 1.38^{+0.21}_{-0.19} for the full, the RS and the blue non-RS populations, respectively, but with ˜40% to 55% cluster to cluster variation and no statistically significant redshift or mass trends. The number of galaxies within the virial region N200 exhibits a mass trend indicating that the number of galaxies per unit total mass is lower in the most massive clusters, and shows no significant redshift trend. The red sequence (RS) fraction within R200 is (68 ± 3)% at z = 0.46, varies from ˜55% at z = 1 to ˜80% at z = 0.1, and exhibits intrinsic variation among clusters of ˜14%. We discuss a model that suggests the observed redshift trend in RS fraction favors a transformation timescale for infalling field galaxies to become RS galaxies of 2 to 3 Gyr.

  7. 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.

  8. Cortical responses elicited by luminance and compound stimuli modulated by pseudo-random sequences: comparison between normal trichromats and congenital red-green color blinds.

    PubMed

    Risuenho, Bárbara B O; Miquilini, Letícia; Lacerda, Eliza Maria C B; Silveira, Luiz Carlos L; Souza, Givago S

    2015-01-01

    Conventional pattern-reversal visual evoked cortical potential (VECP) shows positivity for luminance and chromatic equiluminant stimuli while conventional pattern-onset VECP shows positivity for luminance pattern-onset and negativity for chromatic pattern-onset. We evaluated how the presentation mode affects VECPs elicited by luminance and compound (luminance plus chromatic) pseudo-random stimulation. Eleven normal trichromats and 17 red-green color-blinds were studied. Pattern-reversal and pattern-onset luminance and compound (luminance plus red-green) gratings were temporally modulated by m-sequence. We used a cross-correlation routine to extract the first order kernel (K1) and the first and second slices of the second order kernel (K2.1 and K2.2, respectively) from the VECP response. We integrated the amplitude of VECP components as a function of time in order to estimate its magnitude for each stimulus condition. We also used a normalized cross-correlation method in order to test the similarity of the VECP components. The VECP components varied with the presentation mode and the presence of red-green contrast in the stimuli. In trichromats, for compound conditions, pattern-onset K1, K2.1, and K2.2, and pattern-reversal K2.1 and K2.2 had negative-dominated waveforms at 100 ms. Small negativity or small positivity were observed in dichromats. Trichromats had larger VECP magnitude than color-blinds for compound pattern-onset K1 (with large variability across subjects), compound pattern-onset and pattern-reversal K2.1, and compound pattern-reversal K2.2. Trichromats and color-blinds had similar VECP amplitude for compound pattern-reversal K1 and compound pattern-onset K2.2, as well as for all luminance conditions. The cross-correlation analysis showed high similarity between waveforms of compound pattern-onset K2.1 and pattern-reversal K2.2 as well as pattern-reversal K2.1 and K2.2. We suggest that compound pattern-reversal K2.1 is an appropriate response to study

  9. GALAXY-SCALE STAR FORMATION ON THE RED SEQUENCE: THE CONTINUED GROWTH OF S0s AND THE QUIESCENCE OF ELLIPTICALS

    SciTech Connect

    Salim, Samir; Fang, Jerome J.; Faber, S. M.; Thilker, David A.

    2012-08-20

    This paper examines star formation (SF) in relatively massive, primarily early-type galaxies (ETGs) at z {approx} 0.1. A sample is drawn from bulge-dominated Galaxy Evolution Explorer/Sloan Digital Sky Survey (GALEX/SDSS) galaxies on the optical red sequence with strong UV excess and yet quiescent SDSS spectra. High-resolution far-UV imaging of 27 such ETGs using Hubble Space Telescope Advanced Camera for Surveys/Solar Blind Channel (ACS/SBC) reveals structured UV morphology in 93% of the sample, consistent with low-level ongoing SF ({approx}0.5 M{sub Sun} yr{sup -1}). In 3/4 of the sample the SF is extended on galaxy scales (25-75 kpc), while the rest contains smaller (5-15 kpc) SF patches in the vicinity of an ETG-presumably gas-rich satellites being disrupted. Optical imaging reveals that all ETGs with galaxy-scale SF in our sample have old stellar disks (mostly S0 type). None is classified as a true elliptical. In our sample, galaxy-scale SF takes the form of UV rings of varying sizes and morphologies. For the majority of such objects we conclude that the gas needed to fuel current SF has been accreted from the intergalactic medium, probably in a prolonged, quasi-static manner, leading in some cases to additional disk buildup. The remaining ETGs with galaxy-scale SF have UV and optical morphologies consistent with minor merger-driven SF or with the final stages of SF in fading spirals. Our analysis excludes that all recent SF on the red sequence resulted from gas-rich mergers. We find further evidence that galaxy-scale SF is almost exclusively an S0 phenomenon ({approx}20% S0s have SF) by examining the overall optically red SDSS ETGs. Conclusion is that significant number of field S0s maintain or resume low-level SF because the preventive feedback is not in place or is intermittent. True ellipticals, on the other hand, stay entirely quiescent even in the field.

  10. Enhanced faint companion photometry and astrometry using wavelength diversity.

    PubMed

    Burke, Daniel; Devaney, Nicholas

    2010-11-01

    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 limits 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 Extremely Large Telescope (ELT) that contain quasi-static speckle noise. The simulation includes Angular Differential Imaging and Spectral Differential Imaging to reduce the residual speckle and subsequent multi-wavelength processing. We examine the feasibility of this approach on simulated ELT observations of faint companions.

  11. Complete genome sequence of the orange-red pigmented, radioresistant Deinococcus proteolyticus type strain (MRP(T)).

    PubMed

    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

    2012-05-25

    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 MRP(T) 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 MRP(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 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.

  12. The Origin of the Heaviest Metals in Most Ultra-faint Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Roederer, Ian U.

    2017-01-01

    The heaviest metals found in stars in most ultra-faint dwarf (UFD) galaxies in the Milky Way halo are generally underabundant by an order of magnitude or more when compared with stars in the halo field. Among the heavy elements produced by n-capture reactions, only Sr and Ba can be detected in red giant stars in most UFD galaxies. This limited chemical information is unable to identify the nucleosynthesis process(es) responsible for producing the heavy elements in UFD galaxies. Similar [Sr/Ba] and [Ba/Fe] ratios are found in three bright halo field stars, BD‑18°5550, CS 22185–007, and CS 22891–200. Previous studies of high-quality spectra of these stars report detections of additional n-capture elements, including Eu. The [Eu/Ba] ratios in these stars span +0.41 to +0.86. These ratios and others among elements in the rare Earth domain indicate an r-process origin. These stars have some of the lowest levels of r-process enhancement known, with [Eu/H] spanning ‑3.95 to ‑3.32, and they may be considered nearby proxies for faint stars in UFD galaxies. Direct confirmation, however, must await future observations of additional heavy elements in stars in the UFD galaxies themselves.

  13. Post-main-sequence and POST red giant branch variables with pulsation periods less than one day

    NASA Astrophysics Data System (ADS)

    Eggen, Olin J.

    1994-06-01

    Post-main-sequence (mass 1 to 3 solar masses) and post-giant branch (0.5 to 1 solar mass) pulsators are discussed on the basis of four color and H beta light curves published elsewhere. The post-main-sequence variables, called ultrashort period cepheid (USPC) (delta Sct), pulsate in the fundamental and first harmonic modes of radial pulsation and, in many cases, in nonradial modes. The variables for which photometry allows accurate, luminosity estimates and are known to pulsate simultaneously in the fundamental and first harmonic or in the fundamental mode alone, define a PL relation (MV = -2.80 log P - 0.60, fundamental). It is notable that the slope of this relation is in the range of slopes found for classical cepheids. Accurate V photometry is lacking for many of the variables known as 'anomalous cepheids', but the available data divide them into low mass, pseudocepheids (BL Her and W Vir stars) and post-main-sequence USPC (delta Sct) variables. Four USPC in NGC 5053 and six in NGC 6466, for which accurate photometry is available, give remarkably consistent moduli of 16.06 +/- 0.05 and 15.98 +/- 0.08 mag, respectively, for the clusters, in which they are blue stragglers similar to SX Phe in Kapteyn's star group. The assumption that the four post-giant branch variables, called VSPC (RR Lyr), S Ari, SU Dra, and ST Leo in Kapteyn's star group and RR Lyr in the Groombridge 1830 group, are physical members of these groups and share their V-velocities, leads to a calibration of the photometry for the derivation of reddening, luminosity, and heavy element abundance of 45 field variables. The resulting reddenings are consistent with values obtained by other methods and the metallicities are consistent with the most accurately available spectroscopic determinations of delta S and of Ca II K. The luminosities of the bulk of the variables confirm Sandage's (1993) relation between MV and (Fe/H). Four or five of the field variables are probably binary, including BB Vir

  14. 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

  15. The VIMOS Public Extragalactic Redshift Survey (VIPERS):. A quiescent formation of massive red-sequence galaxies over the past 9 Gyr

    NASA Astrophysics Data System (ADS)

    Fritz, A.; Scodeggio, M.; Ilbert, O.; Bolzonella, M.; Davidzon, I.; Coupon, J.; Garilli, B.; Guzzo, L.; Zamorani, G.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bottini, D.; Branchini, E.; Cappi, A.; Cucciati, O.; De Lucia, G.; de la Torre, S.; Franzetti, P.; Fumana, M.; Granett, B. R.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; McCracken, H. J.; Paioro, L.; Polletta, M.; Pollo, A.; Schlagenhaufer, H.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Moscardini, L.; Nichol, R. C.; Peacock, J. A.; Percival, W. J.; Phleps, S.; Wolk, M.

    2014-03-01

    We explore the evolution of the colour-magnitude relation (CMR) and luminosity function (LF) at 0.4 < z < 1.3 from the VIMOS Public Extragalactic Redshift Survey (VIPERS) using ~45 000 galaxies with precise spectroscopic redshifts down to i'AB < 22.5 over ~10.32 deg2 in two fields. From z = 0.5 to z = 1.3 the LF and CMR are well defined for different galaxy populations and M*B evolves by ~1.04(1.09) ± 0.06(0.10) mag for the total (red) galaxy sample. We compare different criteria for selecting early-type galaxies: (1) a fixed cut in rest-frame (U - V) colours, (2) an evolving cut in (U - V) colours, (3) a rest-frame (NUV - r') - (r' - K) colour selection, and (4) a spectral-energy-distribution classification. The completeness and contamination varies for the different methods and with redshift, but regardless of the method we measure a consistent evolution of the red-sequence (RS). Between 0.4 < z < 1.3 we find a moderate evolution of the RS intercept of Δ(U - V) = 0.28 ± 0.14 mag, favouring exponentially declining star formation (SF) histories with SF truncation at 1.7 ≤ z ≤ 2.3. Together with the rise in the number density of red galaxies by 0.64 dex since z = 1, this suggests a rapid build-up of massive galaxies (M⋆ > 1011 M⊙) and expeditious RS formation over a short period of ~1.5 Gyr starting before z = 1. This is supported by the detection of ongoing SF in early-type galaxies at 0.9 < z < 1.0, in contrast with the quiescent red stellar populations of early-type galaxies at 0.5 < z < 0.6. There is an increase in the observed CMR scatter with redshift, which is two times larger than observed in galaxy clusters and at variance with theoretical model predictions. We discuss possible physical mechanisms that support the observed evolution of the red galaxy population. Our findings point out that massive galaxies have experienced a sharp SF quenching at z ~ 1 with only limited additional merging. In contrast, less-massive galaxies experience a mix of SF

  16. PESSTO monitoring of SN 2012hn: further heterogeneity among faint Type I supernovae

    NASA Astrophysics Data System (ADS)

    Valenti, S.; Yuan, F.; Taubenberger, S.; Maguire, K.; Pastorello, A.; Benetti, S.; Smartt, S. J.; Cappellaro, E.; Howell, D. A.; Bildsten, L.; Moore, K.; Stritzinger, M.; Anderson, J. P.; Benitez-Herrera, S.; Bufano, F.; Gonzalez-Gaitan, S.; McCrum, M. G.; Pignata, G.; Fraser, M.; Gal-Yam, A.; Le Guillou, L.; Inserra, C.; Reichart, D. E.; Scalzo, R.; Sullivan, M.; Yaron, O.; Young, D. R.

    2014-01-01

    We present optical and infrared monitoring data of SN 2012hn collected by the Public European Southern Observatory Spectroscopic Survey for Transient Objects. We show that SN 2012hn has a faint peak magnitude (MR ˜ -15.65) and shows no hydrogen and no clear evidence for helium in its spectral evolution. Instead, we detect prominent Ca II lines at all epochs, which relates this transient to previously described `Ca-rich' or `gap' transients. However, the photospheric spectra (from -3 to +32 d with respect to peak) of SN 2012hn show a series of absorption lines which are unique and a red continuum that is likely intrinsic rather than due to extinction. Lines of Ti II and Cr II are visible. This may be a temperature effect, which could also explain the red photospheric colour. A nebular spectrum at +150 d shows prominent Ca II, O I, C I and possibly Mg I lines which appear similar in strength to those displayed by core-collapse supernovae (SNe). To add to the puzzle, SN 2012hn is located at a projected distance of 6 kpc from an E/S0 host and is not close to any obvious star-forming region. Overall SN 2012hn resembles a group of faint H-poor SNe that have been discovered recently and for which a convincing and consistent physical explanation is still missing. They all appear to explode preferentially in remote locations offset from a massive host galaxy with deep limits on any dwarf host galaxies, favouring old progenitor systems. SN 2012hn adds heterogeneity to this sample of objects. We discuss potential explosion channels including He-shell detonations and double detonations of white dwarfs as well as peculiar core-collapse SNe.

  17. The CFHT (MOS/PUMA) faint quasar survey

    NASA Astrophysics Data System (ADS)

    Schade, David

    A multi-aperture spectroscopic survey for faint quasars has been carried out at Canada-France-Hawaii telescope. The survey is capable of reaching two magnitudes deeper into the luminosity function at redshifts greater than 3 than the deepest existing surveys. The technique is discussed and preliminary results are presented.

  18. 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

  19. 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.

  20. 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.

  1. Characterization of microRNAs by deep sequencing in red claw crayfish Cherax quadricarinatus haematopoietic tissue cells after white spot syndrome virus infection.

    PubMed

    Zhao, Meng-Ru; Meng, Chuang; Xie, Xiao-Lu; Li, Cheng-Hua; Liu, Hai-Peng

    2016-12-01

    White spot syndrome virus (WSSV) is one of the most prevalent and widespread viruses in both shrimp and crayfish aquaculture. MicroRNAs (miRNAs) are crucial post-transcriptional regulators and play critical roles in cell differentiation and proliferation, apoptosis, signal transduction and immunity. In this study, miRNA expression profiles were identified via deep sequencing in red claw crayfish Cherax quadricarinatus haematopoietic tissue (Hpt) cell cultures infected with WSSV at both early (i.e., 1 hpi) and late (i.e., 12 hpi) infection stages. The results showed that 2 known miRNAs, namely, miR-7 and miR-184 play key roles in immunity. Meanwhile, 106 novel miRNA candidates were predicted by software in these combined miRNA transcriptomes. Compared with two control groups, 36 miRNAs showed significantly different expression levels after WSSV challenge. Furthermore, 10 differentially expressed miRNAs in WSSV-exposed Hpt cells were randomly selected for expression analysis by quantitative real-time RT-PCR. Consistent with the expression profiles identified by deep sequencing, RT-PCR showed a significant increase or decrease in miRNA expression in Hpt cells after WSSV infection. Prediction of targets of miRNAs such as miR-7, cqu-miR-52, cqu-miR-126 and cqu-miR-141 revealed that their target genes have diverse biological roles, including not only immunity but also transcriptional regulation, energy metabolism, cell communication, cell differentiation, cell death, autophagy, endocytosis and apoptosis. These results provide insight into the molecular mechanism of WSSV infection and highlight the function of miRNAs in the regulation of the immune response against WSSV infection in crustaceans.

  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 High Orbit Debris Observations with ISON Optical Network

    NASA Astrophysics Data System (ADS)

    Molotov, I.; Agapov, V.

    New cooperation for global monitoring of space objects at high orbits, International Scientific Optical Network (ISON), is appeared under auspices of the Keldysh Institute of Applied Mathematics of the Russian Academy of Sciences. ISON provides the observations of faint deep space debris in cooperation with team of the Astronomical Institute of the University of Bern (AIUB) since 2004. It is jointly discovered already about 500 faint space debris fragments at high orbits and almost 200 of them are continuously tracked with ISON. Presence of space debris clouds created in earlier suspected fragmentations of GEO objects is proved by long deterministic observations of individual members of the clouds. For the first time, a large amount of data on long time intervals is obtained for objects with high area-to-mass ratio (AMR). Till present, the uncatalogued faint deep debris are discovering mainly with Teide ESA OGS telescope and Crimean observatory in Nauchny, while object tracking is providing by cooperation of the 0.5-2.6-m class telescopes including Zimmerwald, Gissar, Mondy, Abastumany, Arkhyz, Mayaki, Andrushivka and Terskol. During 2009 it is planned to join several telescopes with large field of view (1.3 - 2.3 degree) in Ussuriysk, Krasnojarsk, Mondy, Nauchniy, Andrushivka, Abastumani, Mayaki and Kitab into semi-automatic network in order to try to establish the faint debris quasi continuous orbit maintenance. It is planned to use survey mode for this purpose as it is adjusted now for brighter GEO objects with ISON survey subsystem of 22-cm telescopes. Along with sensors development, it is elaborated and tested a few survey modes and algorithm permitting to find correlation between short arc tracks of non-correlated objects in order to discovery of new objects and to establish their orbits.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. Chemical Diversity in the Ultra-faint Dwarf Galaxy Tucana II

    NASA Astrophysics Data System (ADS)

    Ji, Alexander P.; Frebel, Anna; Ezzeddine, Rana; Casey, Andrew R.

    2016-11-01

    We present the first detailed chemical abundance study of the ultra-faint dwarf galaxy Tucana II, based on high-resolution Magellan/MIKE spectra of four red giant stars. The metallicities of these stars range from [Fe/H] = -3.2 to -2.6, and all stars are low in neutron-capture abundances ([Sr/Fe] and [Ba/Fe] < -1). However, a number of anomalous chemical signatures are present. One star is relatively metal-rich ([Fe/H] = -2.6) and shows [Na, α, Sc/Fe] < 0, suggesting an extended star formation history with contributions from AGB stars and SNe Ia. Two stars with [Fe/H] < -3 are mildly carbon-enhanced ([C/Fe] ˜ 0.7) and may be consistent with enrichment by faint supernovae, if such supernovae can produce neutron-capture elements. A fourth star with [Fe/H] = -3 is carbon-normal, and exhibits distinct light element abundance ratios from the carbon-enhanced stars. This carbon-normal star implies that at least two distinct nucleosynthesis sources, both possibly associated with Population III stars, contributed to the early chemical enrichment of this galaxy. Despite its very low luminosity, Tucana II shows a diversity of chemical signatures that preclude it from being a simple “one-shot” first galaxy yet still provide a window into star and galaxy formation in the early universe. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  9. Abundances in Stars from the Red Giant Branch Tip to Near the Main-Sequence Turnoff in M71. III. Abundance Ratios

    NASA Astrophysics Data System (ADS)

    Ramírez, Solange V.; Cohen, Judith G.

    2002-06-01

    We present abundance ratios for 23 elements with respect to Fe in a sample of stars with a wide range in luminosity, from luminous giants to stars near the turnoff in a globular cluster. Our sample of 25 stars in M71 includes 10 giant stars more luminous than the red horizontal branch (RHB), three HB stars, nine giant stars less luminous than the RHB, and three stars near the turnoff. The analyzed spectra, obtained with HIRES at the Keck Observatory, are of high dispersion (R=λ/Δλ=35,000). We find that the neutron capture, the iron peak, and the α-element abundance ratios show no trend with Teff and low scatter around the mean between the top of the RGB and near the main-sequence turnoff. The α-elements Mg, Ca, Si, and Ti are overabundant relative to Fe. The anticorrelation between O and Na abundances observed in other metal-poor globular clusters is detected in our sample and extends to the main sequence. A statistically significant correlation between Al and Na abundances is observed among the M71 stars in our sample, extending to MV=+1.8, fainter than the luminosity of the RGB bump in M5. Lithium is varying, as expected, and Zr may be varying from star to star as well. M71 appears to have abundance ratios very similar to M5, whose bright giants were studied by Ivans et al., but seems to have a smaller amplitude of star-to-star variations at a given luminosity, as might be expected from its higher metallicity. Neither extremely O-poor, Na-rich stars nor extremely O-rich, Na-poor, stars such as are observed in M5 and in M13, are present in our sample of M71 stars. The results of our abundance analysis of 25 stars in M71 provide sufficient evidence of abundance variations at unexpectedly low luminosities to rule out the mixing scenario. Either alone or, even more powerfully, combined with other recent studies of C and N abundances in M71 stars, the existence of such abundance variations cannot be reproduced within the context of our current understanding of

  10. 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 ...

  11. Long-Term Continuous Double Station Observation of Faint Meteor Showers

    PubMed Central

    Vítek, Stanislav; Páta, Petr; Koten, Pavel; Fliegel, Karel

    2016-01-01

    Meteor detection and analysis is an essential topic in the field of astronomy. In this paper, a high-sensitivity and high-time-resolution imaging device for the detection of faint meteoric events is presented. The instrument is based on a fast CCD camera and an image intensifier. Two such instruments form a double-station observation network. The MAIA (Meteor Automatic Imager and Analyzer) system has been in continuous operation since 2013 and has successfully captured hundreds of meteors belonging to different meteor showers, as well as sporadic meteors. A data processing pipeline for the efficient processing and evaluation of the massive amount of video sequences is also introduced in this paper. PMID:27649179

  12. Long-Term Continuous Double Station Observation of Faint Meteor Showers.

    PubMed

    Vítek, Stanislav; Páta, Petr; Koten, Pavel; Fliegel, Karel

    2016-09-14

    Meteor detection and analysis is an essential topic in the field of astronomy. In this paper, a high-sensitivity and high-time-resolution imaging device for the detection of faint meteoric events is presented. The instrument is based on a fast CCD camera and an image intensifier. Two such instruments form a double-station observation network. The MAIA (Meteor Automatic Imager and Analyzer) system has been in continuous operation since 2013 and has successfully captured hundreds of meteors belonging to different meteor showers, as well as sporadic meteors. A data processing pipeline for the efficient processing and evaluation of the massive amount of video sequences is also introduced in this paper.

  13. OPTICAL–INFRARED PROPERTIES OF FAINT 1.3 mm SOURCES DETECTED WITH ALMA

    SciTech Connect

    Hatsukade, Bunyo; Yabe, Kiyoto; Ohta, Kouji; Seko, Akifumi; Makiya, Ryu; Akiyama, Masayuki

    2015-09-10

    We report optical-infrared (IR) properties of faint 1.3 mm sources (S{sub 1.3mm} = 0.2–1.0 mJy) detected with the Atacama Large Millimeter/submillimeter Array (ALMA) in the Subaru/XMM-Newton Deep Survey field. We searched for optical/IR counterparts of eight ALMA-detected sources (≥4.0σ, the sum of the probability of spurious source contamination is ∼1) in a K-band source catalog. Four ALMA sources have K-band counterpart candidates within a 0.″4 radius. Comparison between ALMA-detected and undetected K-band sources in the same observing fields shows that ALMA-detected sources tend to be brighter, more massive, and more actively forming stars. While many of the ALMA-identified submillimeter-bright galaxies (SMGs) in previous studies lie above the sequence of star-forming galaxies in the stellar mass–star formation rate plane, our ALMA sources are located in the sequence, suggesting that the ALMA-detected faint sources are more like “normal” star-forming galaxies rather than “classical” SMGs. We found a region where multiple ALMA sources and K-band sources reside in a narrow photometric redshift range (z ∼ 1.3–1.6) within a radius of 5″ (42 kpc if we assume z = 1.45). This is possibly a pre-merging system and we may be witnessing the early phase of formation of a massive elliptical galaxy.

  14. DISTRIBUTION OF FAINT ATOMIC GAS IN HICKSON COMPACT GROUPS

    SciTech Connect

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

    2015-10-10

    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.

  15. 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.

  16. Intermediate-band photometry of faint standard stars

    NASA Technical Reports Server (NTRS)

    Dawson, D. W.

    1976-01-01

    The David Dunlap Observatory system uses six intermediate-band filters whose central wavelengths were chosen to cover important features in the spectrum of a late-type star. Calibrations of the color indices with physical parameters, allow one to estimate T sub eff, log g, Fe/H, M sub v and reddening directly from the photometry. Although a number of standards lists exist, only a small fraction of the stars is fainter than V=6. It is desirable to add to the numbers of faint standards. Results are presented of photometry of sixteen stars obtained during a program of variable-star photometry at Blue Mesa Observatory.

  17. A survey for faint variable objects in SA 57

    SciTech Connect

    Trevese, D.; Pittella, G.; Kron, R.G.; Koo, D.C.; Bershady, M.; Roma, Osservatorio Astronomico; ESA, European Space Research Institute, Frascati; Yerkes Observatory, Williams Bay, WI; Space Telescope Science Institute, Baltimore, MD; Lick Observatory, Santa Cruz, CA; Chicago Univ., IL )

    1989-07-01

    Nine Mayall 4 m prime-focus Kodak IIIa-J plates spanning an 11-yr baseline are analyzed in a uniform manner for the detection of variable objects to B = 22.6 at the level of Sigma of about 0.1 mag. Techniques are developed that succeed in independently finding objects already known to be variable, namely a sample of QSOs. Few additional objects were identified as variables with high certainty. The principal result, therefore, is an upper limit both to variable QSOs not previously identified by other techniques, and an upper limit at faint magnitudes on other classes of variable objects. 21 refs.

  18. 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.

  19. SOLiD SAGE sequencing shows differential gene expression in jejunal lymph node samples of resistant and susceptible red deer (Cervus elaphus) challenged with Mycobacterium avium subsp. paratuberculosis.

    PubMed

    Mackintosh, C G; Griffin, J F T; Scott, I C; O'Brien, R; Stanton, J L; MacLean, P; Brauning, R

    2016-01-01

    This study compared in vivo lymph node gene expression levels between six young red deer that were either relatively resistant (R) or susceptible (S) to paratuberculosis following experimental challenge with Mycobacterium avium subsp. paratuberculosis. Intestinal lymph nodes were biopsied at 4, 12 and 50 weeks post challenge (pc) and parallel changes in histopathology, immunology and bacterial load monitored. SOLiD SAGE (serial analysis of gene expression) next generation sequencing of biopsied lymph node samples generated a total of 373 million transcript tags 26-28bp in length after filtering. A total of 36,632 unique transcripts were identified and 14,325 of these were able to be annotated. The copy number of each transcript was counted, averaged and compared for R and S animals (R-S). P values and False Discovery Rates (FDR) were calculated for each transcript. Genes differentially upregulated ≥2 fold (FDR<0.5) totalled 9, 40 and 32 in R animals (+ values) and 23, 164 and 47 in S animals (- values) at weeks 4, 12, and 50pc, respectively. Transcripts displaying greatest differential expression between R and S animals at each time point were IFIT2 (189 fold) and S100A8 (-32.7 fold) at week 4, LRR1 (52.7 fold), SERPINF2 (-214.6 fold) at week 12 and CEACAM8 (84.6 fold), and STK31 (-129.5 fold) at week 50, respectively. All 9 genes significantly upregulated at week 4 in R animals relate specifically to host defence and all involve Type I interferon stimulated genes. By contrast genes upregulated in S animals at week 4, relate predominantly to inflammation, but also involve adaptive immune responses, mitochondrial function and apoptosis regulation. At week 12, the genes differentially upregulated in R animals are linked predominantly to regulation of adaptive immunity and mucosal immunity, while many of the genes in S animals are associated with pro-inflammatory interleukins involved with innate and adaptive immunity. These correlated with greater lesion severity

  20. A Tool for Optimizing Observation Planning for Faint Moving Objects

    NASA Astrophysics Data System (ADS)

    Arredondo, Anicia; Bosh, Amanda S.; Levine, Stephen

    2016-10-01

    Observations of small solar system bodies such as trans-Neptunian objects and Centaurs are vital for understanding the basic properties of these small members of our solar system. Because these objects are often very faint, large telescopes and long exposures may be necessary, which can result in crowded fields in which the target of interest may be blended with a field star. For accurate photometry and astrometry, observations must be planned to occur when the target is free of background stars; this restriction results in limited observing windows. We have created a tool that can be used to plan observations of faint moving objects. Features of the tool include estimates of best times to observe (when the object is not too near another object), a finder chart output, a list of possible astrometric and photometric reference stars, and an exposure time calculator. This work makes use of the USNOFS Image and Catalogue Archive operated by the United States Naval Observatory, Flagstaff Station (S.E. Levine and D.G. Monet 2000), the JPL Horizons online ephemeris service (Giorgini et al. 1996), the Minor Planet Center's MPChecker (http://cgi.minorplanetcenter.net/cgi-bin/checkmp.cgi), and source extraction software SExtractor (Bertin & Arnouts 1996). Support for this work was provided by NASA SSO grant NNX15AJ82G.

  1. The faint radio AGN population in the spotlight

    NASA Astrophysics Data System (ADS)

    Herrera Ruiz, Noelia; Middelberg, Enno

    2016-08-01

    To determine the AGN component in the faint radio population is fundamental in galaxy evolution studies. A relatively easy and direct way to determine which galaxies do have a radio-active AGN is a detection using the Very Long Baseline Interferometry (VLBI) technique. The goal of this project is to study with statistically relevant numbers the faint radio source population using VLBI observations. To achieve this goal, the project is divided into two parts. In the first part, we have observed ~3000 radio sources in the COSMOS extragalactic field with the Very Long Baseline Array (VLBA) at 1.4GHz. We have detected 468 sources. In the second part, we have observed ~200 radio sources in the COSMOS field with extremely high sensitivity using the VLBA together with the Green Bank Telescope (GBT) at 1.4GHz, to explore an even fainter population in the flux density regime of tens of uJy. We are currently calibrating this data. In this overview I will present the survey design, observations, and calibration, along with some first results.

  2. 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).

  3. 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.

  4. Eye redness

    MedlinePlus

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

  5. Diet analysis by next-generation sequencing indicates the frequent consumption of introduced plants by the critically endangered red-headed wood pigeon (Columba janthina nitens) in oceanic island habitats.

    PubMed

    Ando, Haruko; Setsuko, Suzuki; Horikoshi, Kazuo; Suzuki, Hajime; Umehara, Shoko; Inoue-Murayama, Miho; Isagi, Yuji

    2013-10-01

    Oceanic island ecosystems are vulnerable to the introduction of alien species, and they provide a habitat for many endangered species. Knowing the diet of an endangered animal is important for appropriate nature restoration efforts on oceanic islands because introduced species may be a major component of the diets of some endangered species. DNA barcoding techniques together with next-generation sequencing may provide more detailed information on animal diets than other traditional methods. We performed a diet analysis using 48 fecal samples from the critically endangered red-headed wood pigeon that is endemic to the Ogasawara Islands based on chloroplast trnL P6 loop sequences. The frequency of each detected plant taxa was compared with a microhistological analysis of the same sample set. The DNA barcoding approach detected a much larger number of plants than the microhistological analysis. Plants that were difficult to identify by microhistological analysis after being digested in the pigeon stomachs were frequently identified only by DNA barcoding. The results of the barcoding analysis indicated the frequent consumption of introduced species, in addition to several native species, by the red-headed wood pigeon. The rapid eradication of specific introduced species may reduce the food resources available to this endangered bird; thus, balancing eradication efforts with the restoration of native food plants should be considered. Although some technical problems still exist, the trnL approach to next-generation sequencing may contribute to a better understanding of oceanic island ecosystems and their conservation.

  6. Diet analysis by next-generation sequencing indicates the frequent consumption of introduced plants by the critically endangered red-headed wood pigeon (Columba janthina nitens) in oceanic island habitats

    PubMed Central

    Ando, Haruko; Setsuko, Suzuki; Horikoshi, Kazuo; Suzuki, Hajime; Umehara, Shoko; Inoue-Murayama, Miho; Isagi, Yuji

    2013-01-01

    Oceanic island ecosystems are vulnerable to the introduction of alien species, and they provide a habitat for many endangered species. Knowing the diet of an endangered animal is important for appropriate nature restoration efforts on oceanic islands because introduced species may be a major component of the diets of some endangered species. DNA barcoding techniques together with next-generation sequencing may provide more detailed information on animal diets than other traditional methods. We performed a diet analysis using 48 fecal samples from the critically endangered red-headed wood pigeon that is endemic to the Ogasawara Islands based on chloroplast trnL P6 loop sequences. The frequency of each detected plant taxa was compared with a microhistological analysis of the same sample set. The DNA barcoding approach detected a much larger number of plants than the microhistological analysis. Plants that were difficult to identify by microhistological analysis after being digested in the pigeon stomachs were frequently identified only by DNA barcoding. The results of the barcoding analysis indicated the frequent consumption of introduced species, in addition to several native species, by the red-headed wood pigeon. The rapid eradication of specific introduced species may reduce the food resources available to this endangered bird; thus, balancing eradication efforts with the restoration of native food plants should be considered. Although some technical problems still exist, the trnL approach to next-generation sequencing may contribute to a better understanding of oceanic island ecosystems and their conservation. PMID:24324859

  7. 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

  8. 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.

  9. 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

  10. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... 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 ... 2000 - The Red Sea between the East Africa coast and Saudi Arabian peninsula. project:  MISR category:  ...

  11. 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...

  12. 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.

  13. 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.

  14. Faint UBVRI Standard Star Fields at +50° Declination

    NASA Astrophysics Data System (ADS)

    Clem, James L.; Landolt, Arlo U.

    2016-10-01

    Precise and accurate CCD-based UBVRI photometry is presented for ˜2000 stars distributed around the sky in a declination zone centered approximately at +50°. Their photometry has been calibrated to the standard Johnson UBV and Kron-Cousins RI systems through observations of the UBVRI standard stars presented in the various works of Landolt. The magnitude and color range for these stars are 12 ≲ V ≲ 22 and -0.3 ≲ (B - V) ≲ 1.8, respectively. Each star averages 13 measures in each UBVRI filter from data taken on 41 different photometric nights obtained over a 21 month period. Hence, there now exists a network of faint UBVRI photometric standard stars centered on the declination zones δ = -50°, 0°, and +50°.

  15. 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.

  16. Clustering Effect on the Number Count of Faint Galaxies

    NASA Astrophysics Data System (ADS)

    Yamashita, K.

    1992-08-01

    We have tested the cosmological model of Ω0 = 1 and Λ = 0 against the faint galaxy number count taking the clustering effect of galaxies into account. The evolution of the large scale structure is simulated numerically by means of the particle mesh method in three dimensional space. We use 643 particles and the same number of mesh cells. We have found that the flat Friedmann-Robertson-Walker model without the cosmological constant does not explain the excess of the number count observed by Tyson even if the clustering effect is taken into account, provided the cluster size and the correlation length among clusters are less than the simulation box size of 128 h-1 Mpc. The clustering on scales larger than 128 h-1 Mpc is also considered.

  17. First results from the Faint Object Camera - SN 1987A

    NASA Technical Reports Server (NTRS)

    Jakobsen, P.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.

    1991-01-01

    The first images of SN 1987A taken on day 1278 after outburst with the Faint Object Camera on board the Hubble Space Telescope are presented. The supernova is well detected and resolved spatially in three broadband ultraviolet exposures spanning the 1500-3800 A range and in a narrow-band image centered on the forbidden O III 5007 line. Simple uniform disk fits to the profiles of SN 1987A yield an average angular diameter of 170 + or - 30 mas, corresponding to an average expansion velocity of 6000 km/s. The derived broadband ultraviolet fluxes, when corrected for interstellar absorption, indicate a blue ultraviolet spectrum corresponding to a color temperature near 13,000 K.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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

  4. HST NICMOS snapshot survey of faint galaxies at z < 1

    NASA Astrophysics Data System (ADS)

    Hinkley, S.; Im, M.; DEEP Team

    2000-12-01

    During Cycle 7 HST observations, we have obtained NICMOS H-band images of faint field galaxies for which both HST morphological information (in V and/or I) and spectroscopic redshifts are available. The purpose of the NICMOS observation is to provide their morphology in rest frame NIR wavelengths (8000 - 16000 Å), where the effect of dust extinction is less severe, and to obtain their near infrared (NIR) colors. The objects in our field are partly contained in the Groth Strip being studied in detail by the DEEP team. In addition, we have made use of a software package called GIM2D (Simard et al. 2001). This package is designed to perform detailed 2-dimensional decompositions for images of distant galaxies. Using this software, we have obtained structural parameters for the objects in the H-band to complement those parameters in V and I. We will present: i) color gradients inside elliptical galaxies to test models of their formation; ii) the effect of dust extinction on the properties of field galaxies at 0 < z < 1; iii) evolution of V-H, and V-I colors of bulges as well as the B/T ratio of spiral galaxies as a function of redshift; iv) morphological k-correction. The median redshift of our sample is z ~ 0.5 and this corresponds to about one half of the current age of the universe. This work is supported by the STScI grant GO-07895.02-96A.

  5. 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.

  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. 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.

  8. 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

  9. Serendipitous ALMA detections of faint submm galaxies in SERVS

    NASA Astrophysics Data System (ADS)

    Patil, Pallavi; Lacy, Mark; Nyland, Kristina

    2017-01-01

    We present a preliminary ALMA study of faint (<1mJy) submm galaxies with counterparts in the Spitzer Extragalactic Representative Volume Survey (SERVS). SERVS provides post-cryogenic IRAC imaging at 3.6 and 4.5 microns over an 18 deg2 area of the sky over five famous deep fields. The depth of the survey is ~ 2 µJy, and it provides a complete census of galaxies up to z ~ 5. While it is known that bright submm galaxies are associated with dusty, ultra-luminous starforming galaxies at z ~ 2, the sub-mJy population is still not well understood. A key missing piece of information is their morphologies at rest-frame optical wavelengths, which for high-redshift submm galaxies is only accessible through ALMA observations. The high sensitivity, spatial resolution, and positional accuracy of ALMA have enabled us to probe the nature of the sub-mJy population by resolving their spatial extents and improving constraints on their SEDS and photometric redshifts. We are building a catalog of sources by searching the ALMA archive for moderate to deep observations in the area covered by SERVS. This study will help us begin to understand the contribution of obscured star formation to the total star formation rate at high redshift and guide future wide-area surveys of submm galaxies with ALMA.

  10. 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.

  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.

  12. 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.

  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. 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.

  15. Revealing a strongly reddened, faint active galactic nucleus population by stacking deep co-added images

    NASA Astrophysics Data System (ADS)

    Varga, József; Csabai, István.; Dobos, László

    2012-10-01

    More than half of the sources identified by recent radio sky surveys have not been detected by wide-field optical surveys. We present a study, based on our co-added image stacking technique, in which our aim is to detect the optical emission from unresolved, isolated radio sources of the Very Large Array (VLA) Faint Images of the Radio Sky at Twenty-cm (FIRST) survey that have no identified optical counterparts in the Sloan Digital Sky Survey (SDSS) Stripe 82 co-added data set. From the FIRST catalogue, 2116 such radio point sources were selected, and cut-out images, centred on the FIRST coordinates, were generated from the Stripe 82 images. The already co-added cut-outs were stacked once again to obtain images of high signal-to-noise ratio, in the hope that optical emission from the radio sources would become detectable. Multiple stacks were generated, based on the radio luminosity of the point sources. The resulting stacked images show central peaks similar to point sources. The peaks have very red colours with steep optical spectral energy distributions. We have found that the optical spectral index αν falls in the range -2.9 ≤ αν ≤ -2.2 (Sν∝ναν), depending only weakly on the radio flux. The total integration times of the stacks are between 270 and 300 h, and the corresponding 5σ detection limit is estimated to be about mr ≃ 26.6 mag. We argue that the detected light is mainly from the central regions of dust-reddened Type 1 active galactic nuclei. Dust-reddened quasars might represent an early phase of quasar evolution, and thus they can also give us an insight into the formation of massive galaxies. The data used in the paper are available on-line at http://www.vo.elte.hu/doublestacking.

  16. The Distribution of Alpha Elements in Ultra-faint Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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 [α/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 MV > -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 [α/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 (~100 Myr) and less than ~2 Gyr. We further show that the combined population of UFDs has an [α/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].

  17. 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.

  18. Red Sky with Red Mesa

    ScienceCinema

    None

    2016-07-12

    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.

  19. The Origin of Dwarf Galaxies in Clusters: The Faint-End Slope of Abell 85 Galaxy Luminosity Function

    NASA Astrophysics Data System (ADS)

    Agulli, I.; Aguerri, J. A. L.; Barrena, R.; Diaferio, A.; Sánchez-Janssen, R.

    2016-10-01

    Dwarf galaxies (Mb>-18) are important because of their cosmological interest as tests of hierarchical theories. The formation of these galaxies is still an open question but red dwarf galaxies are preferentially located in high density environments, indicating that they are end-products of galaxy transformations in clusters. Deep spectroscopic studies of galaxy clusters are needed to put some constraints on dwarf galaxy formation and evolution. We have observed and analyzed Abell 85, a nearby (z = 0.055) and massive cluster down to M*+6, using the MOS instruments VIMOS@VLT and AF2@WHT. The first and powerful tool to study the characteristics of galaxies and compare with different density environments is the galaxy luminosity function. The comparison of the results for Abell 85 with literature outcomes for clusters and field, allows us to conclude that, at least for this cluster, the environment plays a major role in the nature of the faint-end galaxies, transforming blue dwarfs in the field into red ones in the cluster, but not in the formation of the luminosity function slope.

  20. 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.

  1. Chemical enrichment in Ultra-Faint Dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Romano, Donatella

    2015-08-01

    The origin and evolution of galaxies is one of the great outstanding problems of astrophysics. The elusive, basic processes that govern galaxy formation can be advantageously studied in the simplest structures found orbiting the Milky Way, namely, the newly discovered Ultra-Faint Dwarf (UFD) galaxies. These low luminosity objects are the most dark matter-dominated galaxies known and likely the relics of the complex assembly processes that shaped the Galaxy over a Hubble time. They formed stars long (~12 Gyr) ago and have been quiescent ever since. Their present-day stellar masses are comparable to those of typical Milky Way globular clusters (GCs) but, at variance with GCs, they have large [Fe/H] spreads and average metallicities lower than those of the most metal-poor GCs, which clearly indicates they followed distinct evolutionary paths. The abundance ratios [α/Fe] measured in a few UFD giant stars closely resemble those of similarly metal-poor Galactic halo stars, suggesting that chemical evolution proceeded similarly in different systems at the earliest times. Despite their simplicity, a number of questions remain unanswered with regards to these systems: did they suffer 'one-shot' or extended star formation? what is the level and significance of chemical inhomogeneity inside these systems? was stellar feedback effective in removing all the gas left over from the star formation process, or did the interaction with the environment play a major role? In this contribution we discuss these issues basing on results we got from pure chemical evolution models, as well as three-dimensional hydrodynamical simulations run at subparsec resolution.

  2. On The Nature of Faint Galaxies with Strong UV Excess

    NASA Astrophysics Data System (ADS)

    Cruzen, S.; Weistrop, D.; Angione, R.

    1993-05-01

    Four faint galaxies identified in the Case Low-Dispersion Northern Sky Survey (Stephenson, Pesch, MacConnell 1992,ApJSS,82,471) show unusually strong UV excess in their objective prism spectra. We are currently investigating the nature of these galaxies (CG 1280, CG 1293, CG 1298, CG 1331). The preliminary results from the analysis of the spectra for galaxies CG 1293 (R.A.=15(h}22({m}00^{s)) .0, Decl.=+30deg 29(') .7 [1950]) and CG 1331 (R.A.=15(h}54({m}41^{s)) .9, Decl.=+29deg 57(') .4 [1950]) are presented. Stephenson, Pesch and MacConnell report that both galaxies have blue magnitudes of approximately 17. We obtained observations of these objects on 1992 July 2 and 3 with the CCD spectrograph on the 40-inch telescope at Mount Laguna Observatory. This CCD has an 800 x 800 format and covers an approximate wavelength range of 4000 Angstroms to 7000 Angstroms. Our analysis of the spectra reveals strong Hα emission with broad line profiles characteristic of Seyfert 1 galaxies. The spectrum of CG 1293 indicates a redshift of z = 0.1255 0.0003 and an Hα emission line width of 4180 km/sec (FWHM). The [SII] pair lambda 6717 and lambda 6731 have also been identified. We have determined a preliminary redshift for CG 1331 of z = 0.089 +/- 0.004. The Hα emission line width for CG 1331 is 7350 km/sec (FWHM). Lines corresponding to Hβ and Hγ have also been identified. This research has been supported in part by NASA through the Nevada Space Grant Consortium.

  3. 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.

  4. Astrometric observations of the faint outer satellites of Jupiter during the 1993 opposition

    NASA Technical Reports Server (NTRS)

    Shelus, Peter J.; Whipple, Arthur L.; Benedict, G. F.

    1993-01-01

    Astrometric positions for the faint outer Jovian satellites VI-XIII during the 1993 opposition have been obtained from the measurement of plates taken with the 2.1 m Otto Struve reflector at McDonald Observatory.

  5. Red Hill

    EPA Pesticide Factsheets

    Information about the Red Hill Bulk Fuel Storage Facility in Hawaii Administrative Order on Consent (AOC), an enforceable agreement of the Hawaii Department of Health, the Environmental Protection Agency, and the U.S. Navy -- Defense Logistics Agency.

  6. Population genetic structure and molecular diversity of the red swamp crayfish in China based on mtDNA COI gene sequences.

    PubMed

    Liu, Gang; Zhou, Lizhi

    2016-08-23

    Population genetic structure and molecular diversity are closely related to adaptability, potential and evolutionary of a species, which also reflects its population history. We analyzed the molecular variability and genetic structure among 24 populations of the red swamp crayfish in China based on the COI region. The COI of 687 bp aligned across 44 haplotypes, the average AT content (68.1%) was slightly higher than the AT content (31.9%). AMOVA indicated that a high proportion of the total genetic variance was attributable to variations within populations (87.57%), whereas only 12.43% occurred among populations. The Fst values were between 0.016 and 0.585, and the Nm values were between 0.178 and 15.182 in each population. All of the AMOVA, Fst statistics and Nm values suggested low genetic differentiation, but a high level genetic diversity existed in Chinese populations of Procambarus clarkii. The phylogenetic trees showed that some geographical populations were irregularly distributed according to the river systems while others were matched well, suggesting that genetic differentiation is created largely by geographic isolation.

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. ɛ Ophiuchi: Revisiting a Red Giant

    NASA Astrophysics Data System (ADS)

    Kallinger, T.; Matthews, J. M.; Guenther, D. B.; Gruberbauer, M.; Kuschnig, R.; Weiss, W. W.; MOST Team

    2012-09-01

    In only a decade, seismology of red-giant stars has grown from infancy to adulthood in the study of stellar structure and evolution. The stimulants for this accelerated growth have been space observations, first provided by the WIRE star-tracker and MOST, and continuing with CoRoT and Kepler, having detected oscillations in thousands of cool giants. However, almost all of the stars in this impressive sample are faint, with little known about their basic properties. Even reliable spectral classifications are lacking for many of them. MOST is the only space-based photometer capable of continuous observations of bright red giants for which we have independent constraints (e.g., spectroscopy) essential to extract the internal structure from the stars' p-modes.

  12. 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.

  13. 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.

  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.

  15. Estimating sizes of faint, distant galaxies in the submillimetre regime

    NASA Astrophysics Data System (ADS)

    Lindroos, L.; Knudsen, K. K.; Fan, L.; Conway, J.; Coppin, K.; Decarli, R.; Drouart, G.; Hodge, J. A.; Karim, A.; Simpson, J. M.; Wardlow, J.

    2016-10-01

    We measure the sizes of redshift ˜2 star-forming galaxies by stacking data from the Atacama Large Millimeter/submillimeter Array (ALMA). We use a uv-stacking algorithm in combination with model fitting in the uv-domain and show that this allows for robust measures of the sizes of marginally resolved sources. The analysis is primarily based on the 344 GHz ALMA continuum observations centred on 88 submillimetre galaxies in the LABOCA ECDFS Submillimeter Survey (ALESS). We study several samples of galaxies at z ≈ 2 with M* ≈ 5 × 1010 M⊙, selected using near-infrared photometry (distant red galaxies, extremely red objects, sBzK-galaxies, and galaxies selected on photometric redshift). We find that the typical sizes of these galaxies are ˜0.6 arcsec which corresponds to ˜5 kpc at z = 2, this agrees well with the median sizes measured in the near-infrared z band (˜0.6 arcsec). We find errors on our size estimates of ˜0.1-0.2 arcsec, which agree well with the expected errors for model fitting at the given signal-to-noise ratio. With the uv-coverage of our observations (18-160 m), the size and flux density measurements are sensitive to scales out to 2 arcsec. We compare this to a simulated ALMA Cycle 3 data set with intermediate length baseline coverage, and we find that, using only these baselines, the measured stacked flux density would be an order of magnitude fainter. This highlights the importance of short baselines to recover the full flux density of high-redshift galaxies.

  16. 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.

  17. 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.

  18. The faint limit of the Hubble Space Telescope faint object spectrograph and rejection of the cosmic-ray background

    NASA Technical Reports Server (NTRS)

    Tytler, David; Davis, Christopher

    1995-01-01

    The faintest object which can be observed with the Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) is set by the detector cosmic-ray background and not by object flux. We use data from Beaver and Lyons to show that 48% of the background counts are from cosmic rays which each generate a near instantaneous burst of two or more counts. Setting the FOS threshold parameter REJLIM = 1, which rejects all frames with more than one count increases the ratio of signal-to-dark counts (S/D) by a factor of 1.94, regardless of the frame time or the object signal, because half of the dark counts which arrive in single counts (from either cosmic-ray bursts or thermal dark current photoemission) are rejected at the same rate as the object signal. But the signal-to-noise ratio (SNR proportional to S/square root of S + D) increases by at most a factor of 1.35, and for realistic parameters and taking into account dead time, we expect a gain in SNR of only 1.18. If a diode has failed and now emits noise, no data at all will be recorded. The chance of this occurring is approximately = 10% , and for this reason we do not recommend the use of REJLIM. The two-point correlation function of dark counts per pixel has strong peaks every four pixels, caused by the action of quarter-stepping on the counts from large bursts. The counts from such bursts spread over at least 80-100 diodes, and we show that such bursts can be rejected during data reduction if the data are recorded in RAPID mode with individual exposures of about 35 seconds. The SNR of the spectrum can also be improved by weighting each exposure by its SNR (a function ofthe mean dark count rate at that time), since dark varies by a factor of 2 around an orbit. These two procedures together increase the SNR by a factor of 1.1.3 (a 28% gain in exposure time) in regions of a spectrum where the object is much fainter than the background. We find that the Ly-alpha and O I sky emission lines give at most 4 (counts

  19. DISSECTING THE RED SEQUENCE. IV. THE ROLE OF TRUNCATION IN THE TWO-DIMENSIONAL FAMILY OF EARLY-TYPE GALAXY STAR FORMATION HISTORIES

    SciTech Connect

    Graves, Genevieve J.; Faber, S. M.

    2010-09-20

    In the three-dimensional parameter space defined by velocity dispersion ({sigma}), effective radius (R{sub e}), and effective surface brightness (I{sub e}), early-type galaxies are observed to populate a two-dimensional fundamental plane (FP) with finite thickness. In Paper III of this series, we showed that the thickness of the FP is predominantly due to variations in the stellar mass surface density ({Sigma}{sub *}) inside the effective radius R{sub e} . These variations represent differences in the dark matter fraction inside R{sub e} (or possibly differences in the initial mass function) from galaxy to galaxy. This means that galaxies do not wind up below the FP at lower surface brightness due to the passive fading of their stellar populations; they are structurally different. Here, we show that these variations in {Sigma}{sub *} at fixed dynamical mass (M{sub dyn}) are linked to differences in the galaxy stellar populations, and therefore to differences in their star formation histories. We demonstrate that the ensemble of stellar population and {Sigma}{sub *} variations through the FP thickness can be explained by a model in which early-type galaxies at fixed M{sub dyn} have their star formation truncated at different times. The thickness of the FP can therefore be interpreted as a sequence of truncation times. Galaxies below the FP have earlier truncation times for a given M{sub dyn}, resulting in lower {Sigma}{sub *}, older ages, lower metallicities in both [Fe/H] and [Mg/H], and higher [Mg/Fe]. We show that this model is quantitatively consistent with simple expectations for chemical enrichment in galaxies. We also present fitting functions for luminosity-weighted age, [Fe/H], [Mg/H], and [Mg/Fe] as functions of the FP parameters {sigma}, R{sub e} , and I{sub e} . These provide a new tool for estimating the stellar population properties of quiescent early-type galaxies for which high-quality spectra are not available.

  20. Searching for Faint cataclysmic Variables: Seeking the truth about their Space Density

    NASA Astrophysics Data System (ADS)

    Howell, S. B.; Clowes, R.

    1996-12-01

    The current view of cataclysmic variables is based on theory and observation attempting to reach agreement. However recent work in both these areas has conclusively shown that the present observational sample of CVs is severely limited to intrinsically bright systems, while theory predicts that most should be intrinsically faint. We have begun a program designed to discover faint CVs, ones belonging to the predicted majority population. Using H-alpha and broadband R plates from the UK Schmidt digitized with SuperCOSMOS, we have begun sample selection of candidates to a faint limit of near 20th magnitude. The first spectroscopic results obtained using the ARGUS multi-fiber spectrograph at CTIO will be presented.

  1. 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.

  2. 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

    2016-06-06

    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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. American Red Cross

    MedlinePlus

    ... Espanol Local Red Cross ( ) Change Chapter Edit Zip Code Edit Zip Code Shop the Red Cross Store Toggle Navigation Menu ... Espanol Local Red Cross ( ) Change Chapter Edit Zip Code Edit Zip Code Shop the Red Cross Store ...

  8. Parapoxvirus infections of red deer, Italy.

    PubMed

    Scagliarini, Alessandra; Vaccari, Francesca; Turrini, Filippo; Bianchi, Alessandro; Cordioli, Paolo; Lavazza, Antonio

    2011-04-01

    To characterize parapoxviruses causing severe disease in wild ruminants in Stelvio Park, Italy, we sequenced and compared the DNA of several isolates. Results demonstrated that the red deer isolates are closely related to the parapox of red deer in New Zealand virus.

  9. Parapoxvirus Infections of Red Deer, Italy

    PubMed Central

    Vaccari, Francesca; Turrini, Filippo; Bianchi, Alessandro; Cordioli, Paolo; Lavazza, Antonio

    2011-01-01

    To characterize parapoxviruses causing severe disease in wild ruminants in Stelvio Park, Italy, we sequenced and compared the DNA of several isolates. Results demonstrated that the red deer isolates are closely related to the parapox of red deer in New Zealand virus. PMID:21470460

  10. 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...

  11. 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

  12. Study on the faint star extraction technology with MEMS gyro aided APS star tracker

    NASA Astrophysics Data System (ADS)

    Xing, Fei; Zhao, Borui; Sun, Ting; Xu, Wei; You, Zheng

    2013-08-01

    Star tracker is the most accurate attitude sensor for satellite. Generally speaking, the higher the accuracy, the fainter the star can be sensed by the star tracker. How to extract the faint star from a star image is becoming a critical technology in dynamic condition for star tracker, especially using the APS (Active Pixels Sensor) detector. A novel APS star tracker with MEMS Gyroscope aided system was proposed in this paper that could extremely improve the detection effect and capability for the faint stars. During the exposure time of star tracker, the trajectory of star projection on the detector maybe occupy more than ten pixels due to the satellite rotation. In this situation, the signal-to-noise ratio will decline sharply, and the traditional star extraction method for faint star will take no effect. As a result, the accuracy of star tracker would decline sharply, even more, couldn't work. Using the MEMS Gyroscope, the track of star projection can be predicated and measured, on the basis of which the deconvolution algorithm could be taken to recover the faint star signal. The accuracy of the star projection centroid could be improved obviously, and the dynamic performance of the star tracker would be improved by a magnitude. Meanwhile, the MEMS gyroscope has not less volume, mass and power consumption, which make it more suitable for the application of APS star tracker.

  13. DISCOVERY OF A FAINT QUASAR AT z ∼ 6 AND IMPLICATIONS FOR COSMIC REIONIZATION

    SciTech Connect

    Kim, Yongjung; Im, Myungshin; Jeon, Yiseul; Choi, Changsu; Hong, Jueun; Hyun, Minhee; Jun, Hyunsung David; Kim, Dohyeong; Kim, Duho; Kim, Jae-Woo; Lee, Seong-Kook; Taak, Yoon Chan; Yoon, Yongmin; Kim, Minjin; Park, Won-Kee; Karouzos, Marios; Kim, Ji Hoon; Pak, Soojong E-mail: mim@astro.snu.ac.kr

    2015-11-10

    Recent studies suggest that faint active galactic nuclei may be responsible for the reionization of the universe. Confirmation of this scenario requires spectroscopic identification of faint quasars (M{sub 1450} > −24 mag) at z ≳ 6, but only a very small number of such quasars have been spectroscopically identified so far. Here, we report the discovery of a faint quasar IMS J220417.92+011144.8 at z ∼ 6 in a 12.5 deg{sup 2} region of the SA22 field of the Infrared Medium-deep Survey (IMS). The spectrum of the quasar shows a sharp break at ∼8443 Å, with emission lines redshifted to z = 5.944 ± 0.002 and rest-frame ultraviolet continuum magnitude M{sub 1450} = −23.59 ± 0.10 AB mag. The discovery of IMS J220417.92+011144.8 is consistent with the expected number of quasars at z ∼ 6 estimated from quasar luminosity functions based on previous observations of spectroscopically identified low-luminosity quasars. This suggests that the number of M{sub 1450} ∼ −23 mag quasars at z ∼ 6 may not be high enough to fully account for the reionization of the universe. In addition, our study demonstrates that faint quasars in the early universe can be identified effectively with a moderately wide and deep near-infrared survey such as the IMS.

  14. Constraints on MACHO Dark Matter from Compact Stellar Systems in Ultra-Faint Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Brandt, Timothy

    2017-01-01

    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 ten 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. NASA Sagan Fellow.

  15. 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

  16. On the Dearth of Ultra-faint Extremely Metal-poor Galaxies

    NASA Astrophysics Data System (ADS)

    Sánchez Almeida, J.; Filho, M. E.; Dalla Vecchia, C.; Skillman, E. D.

    2017-02-01

    Local extremely metal-poor galaxies (XMPs) are of particular astrophysical interest since they allow us to look into physical processes characteristic of the early universe, from the assembly of galaxy disks to the formation of stars in conditions of low metallicity. Given the luminosity–metallicity relationship, all galaxies fainter than Mr ≃ ‑13 are expected to be XMPs. Therefore, XMPs should be common in galaxy surveys. However, they are not common, because several observational biases hamper their detection. This work compares the number of faint XMPs in the SDSS-DR7 spectroscopic survey with the expected number, given the known biases and the observed galaxy luminosity function (LF). The faint end of the LF is poorly constrained observationally, but it determines the expected number of XMPs. Surprisingly, the number of observed faint XMPs (∼10) is overpredicted by our calculation, unless the upturn in the faint end of the LF is not present in the model. The lack of an upturn can be naturally understood if most XMPs are central galaxies in their low-mass dark matter halos, which are highly depleted in baryons due to interaction with the cosmic ultraviolet background and to other physical processes. Our result also suggests that the upturn toward low luminosity of the observed galaxy LF is due to satellite galaxies.

  17. Photoelectric Photometry of Faint M-Type Stars in the Direction of the South Galactic Pole

    NASA Astrophysics Data System (ADS)

    Pesch, P.

    1982-04-01

    Photoelectric V (Johnson-Morgan UBV system) and (V I) (Kron-Mayall PVI system) photometry is presented for 54 faint M-type stars from Pesch and Sanduleak's catalog of probable dwarf stars of type M3 and later in the direction of the south galactic pole. The observations were made in November 1978 with the 1.5-m CTIO reflector.

  18. First results from the Faint Object Camera - Images of the gravitational lens system G2237 + 0305

    NASA Technical Reports Server (NTRS)

    Crane, P.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.

    1991-01-01

    Images of the gravitational lens system G2237 + 0305 have been obtained with the Faint Object Camera on board the Hubble Space Telescope. A preliminary analysis of these images is reported here and includes measurements of the relative positions and magnitudes of the lensed images of the QSO, and of the lensing galaxy. No evidence is found for a fifth lensed image.

  19. A VIRUS-P Survey of Galaxy Clusters to Find Faint Lyα-emitting Galaxies

    NASA Astrophysics Data System (ADS)

    McLinden, Emily; Finkelstein, S. L.; Siana, B. D.; Alavi, A.

    2014-01-01

    The VIRUS-P instrument on the 2.7m telescope at the McDonald Observatory was originally built as a prototype of the larger VIRUS instrument that will be used for HETDEX. We demonstrate that this multi-fiber, optical integral field unit spectrograph can be efficiently used to detect faint Lyα-emitting galaxies (LAEs) at intermediate redshift (z = 2-3) with the aid of gravitational lensing from galaxy clusters. The bulk z=2-3 LAEs to date have been discovered with narrowband imaging campaigns, which are highly efficient only at selecting L > L_star galaxies and only over a narrow redshift slice. By making use of gravitational lensing, however, we are able to observe intrinsically very faint galaxies that only appear to have brightnesses ≥ L_star. Gravitationally lensed faint LAEs, such as our sample from VIRUS-P, allow us to go fainter than existing narrowband surveys and therefore allow for better constraints at the faint end of the Lyα luminosity function at these intermediate redshifts.

  20. Chemical evolution of classical and ultra-faint dwarf spheroidal galaxies

    NASA Astrophysics Data System (ADS)

    Vincenzo, F.; Matteucci, F.; Vattakunnel, S.; Lanfranchi, G. A.

    2014-07-01

    We present updated chemical evolution models of two dwarf spheroidal galaxies (Sculptor and Carina) and the first detailed chemical evolution models of two ultra-faint dwarfs (Hercules and Boötes I). Our results suggest that the dwarf spheroidals evolve with a low efficiency of star formation, confirming previous results, and the ultra-faint dwarfs with an even lower one. Under these assumptions, we can reproduce the stellar metallicity distribution function, the [α/Fe] versus [Fe/H] abundance patterns and the total stellar and gas masses observed at the present time in these objects. In particular, for the ultra-faint dwarfs we assume a strong initial burst of star formation, with the mass of the system being already in place at early times. On the other hand, for the classical dwarf spheroidals the agreement with the data is found by assuming the star formation histories suggested by the colour-magnitude diagrams and a longer time-scale of formation via gas infall. We find that all these galaxies should experience galactic winds, starting in all cases before 1 Gyr from the beginning of their evolution. From comparison with Galaxy data, we conclude that it is unlikely that the ultra-faint dwarfs have been the building blocks of the whole Galactic halo, although more data are necessary before drawing firm conclusions.

  1. 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).

  2. THE FAINT END OF THE LUMINOSITY FUNCTION AND LOW SURFACE BRIGHTNESS GALAXIES

    SciTech Connect

    Geller, Margaret J.; Kurtz, Michael J.; Fabricant, Daniel G.; Diaferio, Antonaldo; Dell'Antonio, Ian P. E-mail: mkurtz@cfa.harvard.edu E-mail: adiaferio@cfa.harvard.edu

    2012-04-15

    Smithsonian Hectospec Lensing Survey (SHELS) is a dense redshift survey covering a 4 deg{sup 2} region to a limiting R = 20.6. In the construction of the galaxy catalog and in the acquisition of spectroscopic targets, we paid careful attention to the survey completeness for lower surface brightness dwarf galaxies. Thus, although the survey covers a small area, it is a robust basis for computation of the slope of the faint end of the galaxy luminosity function to a limiting M{sub R} = -13.3 + 5log h. We calculate the faint-end slope in the R band for the subset of SHELS galaxies with redshifts in the range 0.02 {<=}z < 0.1, SHELS{sub 0.1}. This sample contains 532 galaxies with R < 20.6 and with a median surface brightness within the half-light radius of SB{sub 50,R} = 21.82 mag arcsec{sup -2}. We used this sample to make one of the few direct measurements of the dependence of the faint end of the galaxy luminosity function on surface brightness. For the sample as a whole the faint-end slope, {alpha} = -1.31 {+-} 0.04, is consistent with both the Blanton et al. analysis of the Sloan Digital Sky Survey and the Liu et al. analysis of the COSMOS field. This consistency is impressive given the very different approaches of these three surveys. A magnitude-limited sample of 135 galaxies with optical spectroscopic redshifts with mean half-light surface brightness, SB{sub 50,R} {>=} 22.5 mag arcsec{sup -2} is unique to SHELS{sub 0.1}. The faint-end slope is {alpha}{sub 22.5} = -1.52 {+-} 0.16. SHELS{sub 0.1} shows that lower surface brightness objects dominate the faint-end slope of the luminosity function in the field, underscoring the importance of surface brightness limits in evaluating measurements of the faint-end slope and its evolution.

  3. 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

  4. Are the Faint Structures Ahead of Solar Coronal Mass Ejections Real Signatures of Driven Shocks?

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Ok; Moon, Y.-J.; Lee, Jin-Yi; Lee, Kyoung-Sun; Kim, Sujin; Lee, Kangjin

    2014-11-01

    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-1 and median = 1199 km s-1) than Group 2 events (average = 598 km s-1 and median = 518 km s-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-1, 0.65 (34/52) for intermediate CMEs with 500 km s-1 <= V < 1000 km s-1, and 0.14 (3/21) for slow CMEs with V < 500 km s-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.

  5. 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.

  6. 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

  7. 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.

  8. Strongly lensed gravitational waves from intrinsically faint double compact binaries—prediction for the Einstein Telescope

    SciTech Connect

    Ding, Xuheng; Biesiada, Marek; Zhu, Zong-Hong E-mail: marek.biesiada@us.edu.pl

    2015-12-01

    With a fantastic sensitivity improving significantly over the advanced GW detectors, Einstein Telescope (ET) will be able to observe hundreds of thousand inspiralling double compact objects per year. By virtue of gravitational lensing effect, intrinsically unobservable faint sources can be observed by ET due to the magnification by intervening galaxies. We explore the possibility of observing such faint sources amplified by strong gravitational lensing. Following our previous work, we use the merger rates of DCO (NS-NS,BH-NS,BH-BH systems) as calculated by Dominik et al.(2013). It turns out that tens to hundreds of such (lensed) extra events will be registered by ET. This will strongly broaden the ET's distance reach for signals from such coalescences to the redshift range z = 2 − 8. However, with respect to the full inspiral event catalog this magnification bias is at the level of 0.001 and should not affect much cosmological inferences.

  9. 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.

  10. 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.

  11. The Ultra-Faint Dwarfs: Fossils From the Epoch of Reionization?

    NASA Astrophysics Data System (ADS)

    Simon, Josh

    2013-02-01

    We propose to obtain larger samples of spectroscopic metallicity measurements in six ultra-faint dwarf galaxies in order to discern any cosmologically-driven synchronization of their formation histories. Combined with our deep HST photometry of the same galaxies, these data will enable us to measure the age of each galaxy to ~200 Myr. Hierarchical galaxy formation models predict that the ultra-faint dwarfs formed their stars before reionization. We will test whether suppression of star formation in low-mass halos by reionization could be responsible for the missing satellite problem. We will also place improved constraints on the dark matter content of UFDs and search for the most metal-poor stars ever found beyond the Milky Way.

  12. 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.

  13. 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.

  14. 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

  15. The Carnegie-Chicago Hubble Program: Discovery of the Most Distant Ultra-faint Dwarf Galaxy in the Local Universe

    NASA Astrophysics Data System (ADS)

    Lee, Myung Gyoon; Jang, In Sung; Beaton, Rachael; Seibert, Mark; Bono, Giuseppe; Madore, Barry

    2017-02-01

    Ultra-faint dwarf galaxies (UFDs) are the faintest known galaxies, and due to their incredibly low surface brightness, it is difficult to find them beyond the Local Group. We report a serendipitous discovery of a UFD, Fornax UFD1, in the outskirts of NGC 1316, a giant galaxy in the Fornax cluster. The new galaxy is located at a projected radius of 55 kpc in the south–east of NGC 1316. This UFD is found as a small group of resolved stars in the Hubble Space Telescope images of a halo field of NGC 1316, obtained as part of the Carnegie-Chicago Hubble Program. Resolved stars in this galaxy are consistent with being mostly metal-poor red giant branch (RGB) stars. Applying the tip of the RGB method to the mean magnitude of the two brightest RGB stars, we estimate the distance to this galaxy, 19.0 ± 1.3 Mpc. Fornax UFD1 is probably a member of the Fornax cluster. The color–magnitude diagram of these stars is matched by a 12 Gyr isochrone with low metallicity ([Fe/H] ≈ ‑2.4). Total magnitude and effective radius of Fornax UFD1 are MV ≈ ‑7.6 ± 0.2 mag and reff = 146 ± 9 pc, which are similar to those of Virgo UFD1 that was discovered recently in the intracluster field of Virgo by Jang & Lee. Fornax UFD1 is the most distant known UFD that is confirmed by resolved stars. This indicates that UFDs are ubiquitous and that more UFDs remain to be discovered in the Fornax cluster. 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 programs #10505 and #13691.

  16. A comparison of photon counting and current measuring techniques in spectrophotometry of faint sources.

    PubMed

    Tull, R G

    1968-10-01

    The component of dark noise produced by Cerenkov pulses in photomultipliers due to cosmic ray mu mesons is discussed. It is shown by integration of pulse height spectra that this source of noise can be the limiting factor in de measuring spectrophotometry of faint astronomical sources. Direct current methods of photometry are compared with photon counting, and the advantage of photon counting is demonstrated under various operating conditions.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    Yue, Bin; Ferrara, Andrea; Xu, Yidong

    2016-12-01

    Recent measurements of the luminosity function (LF) of galaxies in the Epoch of Reionization (EoR, z ≳ 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 haloes 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 parametrization 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 haloes 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.

  19. 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.

  20. Blind Search of Faint Moving Objects in 3D Data Sets

    DTIC Science & Technology

    2013-09-01

    Blind Search of Faint Moving Objects in 3D Data Sets Phan Dao*, Peter Crabtree and Patrick McNicholl AFRL/RVBYC Tamar Payne Applied...using a simulated object signature superimposed on measured background, and show that the limiting magnitude can be improved by up to 6 visual...magnitudes. A quasi blind search algorithm that identifies the streak of photons, assuming no prior knowledge of orbital information, will be discussed

  1. Astrometric Observations of the Faint Outer Satellites of Jupiter During the 1994 and 1995 Oppositions

    NASA Astrophysics Data System (ADS)

    Whipple, Arthur L.; Shelus, Peter J.; Whited, Randy W.; Cochran, Anita L.; MacQueen, Phillip J.; Benedict, George F.

    1996-07-01

    We present astrometric positions for the faint outer satellites of Jupiter VI-XIII during the 1994 and 1995 oppositions. These positions have been obtained from measurements of photographic plates taken with the 2.1 m Otto Struve reflector and from wide field CCD frames taken with the 0.76 m reflector. Both telescopes are located at McDonald Observatory. The new CCD-based instrumentation and astrometric reduction system is described.

  2. Astrometric observations of the faint satellites of Jupiter and minor planets, 1974-1977

    NASA Technical Reports Server (NTRS)

    Benedict, G. R.; Shelus, P. J.; Mulholland, J. D.

    1978-01-01

    Precise positions of the faint satellites VI-XII of Jupiter during the 1974 opposition, and for Jupiter XIII during the 1976-1977 and 1977-1978 oppositions, have been obtained from plates taken with the 2.1-m Otto Struve reflector of the McDonald Observatory by the use of a new quasi-automatic plate measurement and reduction procedure on a PDS microdensitometer. Observations of selected asteroids, including two of 1977 UB (Chiron) are given also.

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

    DOE PAGES

    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

  4. The SWIRE-VVDS-CFHTLS surveys: stellar mass assembly over the last 10 Gyr. Evidence for a major build up of the red sequence between z = 2 and z = 1

    NASA Astrophysics Data System (ADS)

    Arnouts, S.; Walcher, C. J.; Le Fèvre, O.; Zamorani, G.; Ilbert, O.; Le Brun, V.; Pozzetti, L.; Bardelli, S.; Tresse, L.; Zucca, E.; Charlot, S.; Lamareille, F.; McCracken, H. J.; Bolzonella, M.; Iovino, A.; Lonsdale, C.; Polletta, M.; Surace, J.; Bottini, D.; Garilli, B.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Vettolani, G.; Zanichelli, A.; Adami, C.; Cappi, A.; Ciliegi, P.; Contini, T.; de la Torre, S.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; Guzzo, L.; Marano, B.; Marinoni, C.; Mazure, A.; Meneux, B.; Merighi, R.; Paltani, S.; Pellò, R.; Pollo, A.; Radovich, M.; Temporin, S.; Vergani, D.

    2007-12-01

    , which balances the major fraction of new stars born according to our best SFR estimate (dotρ = 0.025(±0.003) M⊙/Mpc^3/yr). From z = 2 to z = 1.2, we observe a major build-up of the quiescent population with an increase by a factor of 10 in stellar mass (a mass growth rate of 0.063 M⊙/Mpc^3/yr). This rapid evolution suggests that we are observing the epoch when, for the first time in the history of the universe, an increasing fraction of galaxies end their star formation activity and start to build up the red sequence. Based on data obtained with the European southern observatory Very Large Telescope, Paranal, Chile, program 070A-9007(A) and on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS and on data obtained as part of the UKIRT Infrared Deep Sky Survey.

  5. An ultra-faint galaxy candidate discovered in early data from the Magellanic Satellites Survey

    DOE PAGES

    Drlica-Wagner, A.; Bechtol, Keith; Allam, S.; ...

    2016-11-30

    Here, we report a new ultra-faint stellar system found in Dark Energy Camera data from the first observing run of the Magellanic Satellites Survey (MagLiteS). MagLiteS J0644–5953 (Pictor II or Pic II) is a low surface brightness (more » $$\\mu ={28.5}_{-1}^{+1}\\,\\mathrm{mag}\\,\\,\\mathrm{arcsec}{}^{-2}$$ within its half-light radius) resolved overdensity of old and metal-poor stars located at a heliocentric distance of $${45}_{-4}^{+5}\\,\\mathrm{kpc}$$. The physical size ($${r}_{1/2}={46}_{-11}^{+15}\\,\\mathrm{pc}\\,$$) and low luminosity ($${M}_{V}=-{3.2}_{-0.5}^{+0.4}\\,\\mathrm{mag}\\,$$) of this satellite are consistent with the locus of spectroscopically confirmed ultra-faint galaxies. MagLiteS J0644–5953 (Pic II) is located $${11.3}_{-0.9}^{+3.1}\\,\\mathrm{kpc}\\,$$ from the Large Magellanic Cloud (LMC), and comparisons with simulation results in the literature suggest that this satellite was likely accreted with the LMC. The close proximity of MagLiteS J0644–5953 (Pic II) to the LMC also makes it the most likely ultra-faint galaxy candidate to still be gravitationally bound to the LMC.« less

  6. An Ultra-faint Galaxy Candidate Discovered in Early Data from the Magellanic Satellites Survey

    NASA Astrophysics Data System (ADS)

    Drlica-Wagner, A.; Bechtol, K.; Allam, S.; Tucker, D. L.; Gruendl, R. A.; Johnson, M. D.; Walker, A. R.; James, D. J.; Nidever, D. L.; Olsen, K. A. G.; Wechsler, R. H.; Cioni, M. R. L.; Conn, B. C.; Kuehn, K.; Li, T. S.; Mao, Y.-Y.; Martin, N. F.; Neilsen, E.; Noel, N. E. D.; Pieres, A.; Simon, J. D.; Stringfellow, G. S.; van der Marel, R. P.; Yanny, B.

    2016-12-01

    We report a new ultra-faint stellar system found in Dark Energy Camera data from the first observing run of the Magellanic Satellites Survey (MagLiteS). MagLiteS J0644-5953 (Pictor II or Pic II) is a low surface brightness (μ ={28.5}-1+1 {mag} {arcsec}{}-2 within its half-light radius) resolved overdensity of old and metal-poor stars located at a heliocentric distance of {45}-4+5 {kpc}. The physical size ({r}1/2={46}-11+15 {pc} ) and low luminosity ({M}V=-{3.2}-0.5+0.4 {mag} ) of this satellite are consistent with the locus of spectroscopically confirmed ultra-faint galaxies. MagLiteS J0644-5953 (Pic II) is located {11.3}-0.9+3.1 {kpc} from the Large Magellanic Cloud (LMC), and comparisons with simulation results in the literature suggest that this satellite was likely accreted with the LMC. The close proximity of MagLiteS J0644-5953 (Pic II) to the LMC also makes it the most likely ultra-faint galaxy candidate to still be gravitationally bound to the LMC.

  7. An ultra-faint galaxy candidate discovered in early data from the Magellanic Satellites Survey

    SciTech Connect

    Drlica-Wagner, A.; Bechtol, Keith; Allam, S.; Tucker, D. L.; Gruendl, R. A.; Johnson, M. D.; Walker, A. R.; James, D. J.; Nidever, D. L.; Olsen, K. A. G.; Wechsler, R. H.; Cioni, M. R. L.; Conn, B. C.; Kuehn, K.; Li, T. S.; Mao, Y. -Y.; Martin, N. F.; Neilsen, E.; Noel, N. E. D.; Pieres, A.; Simon, J. D.; Stringfellow, G. S.; Marel, R. P. van der; Yanny, B.

    2016-11-30

    Here, we report a new ultra-faint stellar system found in Dark Energy Camera data from the first observing run of the Magellanic Satellites Survey (MagLiteS). MagLiteS J0644–5953 (Pictor II or Pic II) is a low surface brightness ($\\mu ={28.5}_{-1}^{+1}\\,\\mathrm{mag}\\,\\,\\mathrm{arcsec}{}^{-2}$ within its half-light radius) resolved overdensity of old and metal-poor stars located at a heliocentric distance of ${45}_{-4}^{+5}\\,\\mathrm{kpc}$. The physical size (${r}_{1/2}={46}_{-11}^{+15}\\,\\mathrm{pc}\\,$) and low luminosity (${M}_{V}=-{3.2}_{-0.5}^{+0.4}\\,\\mathrm{mag}\\,$) of this satellite are consistent with the locus of spectroscopically confirmed ultra-faint galaxies. MagLiteS J0644–5953 (Pic II) is located ${11.3}_{-0.9}^{+3.1}\\,\\mathrm{kpc}\\,$ from the Large Magellanic Cloud (LMC), and comparisons with simulation results in the literature suggest that this satellite was likely accreted with the LMC. The close proximity of MagLiteS J0644–5953 (Pic II) to the LMC also makes it the most likely ultra-faint galaxy candidate to still be gravitationally bound to the LMC.

  8. Calibration of HST wide field camera for quantitative analysis of faint galaxy images

    NASA Technical Reports Server (NTRS)

    Ratnatunga, Kavan U.; Griffiths, Richard E.; Casertano, Stefano; Neuschaefer, Lyman W.; Wyckoff, Eric W.

    1994-01-01

    We present the methods adopted to optimize the calibration of images obtained with the Hubble Space Telescope (HST) Wide Field Camera (WFC) (1991-1993). Our main goal is to improve quantitative measurement of faint images, with special emphasis on the faint (I approximately 20-24 mag) stars and galaxies observed as a part of the Medium-Deep Survey. Several modifications to the standard calibration procedures have been introduced, including improved bias and dark images, and a new supersky flatfield obtained by combining a large number of relatively object-free Medium-Deep Survey exposures of random fields. The supersky flat has a pixel-to-pixel rms error of about 2.0% in F555W and of 2.4% in F785LP; large-scale variations are smaller than 1% rms. Overall, our modifications improve the quality of faint images with respect to the standard calibration by about a factor of five in photometric accuracy and about 0.3 mag in sensitivity, corresponding to about a factor of two in observing time. The relevant calibration images have been made available to the scientific community.

  9. 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

  10. 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

  11. Syncope (Fainting)

    MedlinePlus

    ... medication. This content was last reviewed September 2016. Arrhythmia • Home • About Arrhythmia • Why Arrhythmia Matters • Understand Your ... the Terms and Conditions and Privacy Policy Printable Arrhythmia Information Sheets What is Arrhythmia? What is Atrial ...

  12. The VVDS type-1 AGN sample: the faint end of the luminosity function

    NASA Astrophysics Data System (ADS)

    Bongiorno, A.; Zamorani, G.; Gavignaud, I.; Marano, B.; Paltani, S.; Mathez, G.; Møller, P.; Picat, J. P.; Cirasuolo, M.; Lamareille, F.; Bottini, D.; Garilli, B.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Cappi, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Guzzo, L.; Ilbert, O.; Iovino, A.; McCracken, H. J.; Marinoni, C.; Mazure, A.; Meneux, B.; Merighi, R.; Pellò, R.; Pollo, A.; Pozzetti, L.; Radovich, M.; Zucca, E.; Hatziminaoglou, E.; Polletta, M.; Bondi, M.; Brinchmann, J.; Cucciati, O.; de la Torre, S.; Gregorini, L.; Mellier, Y.; Merluzzi, P.; Temporin, S.; Vergani, D.; Walcher, C. J.

    2007-09-01

    In a previous paper (Gavignaud et al. 2006, A&A, 457, 79), we presented the type-1 Active Galactic Nuclei (AGN) sample obtained from the first epoch data of the VIMOS-VLT Deep Survey (VVDS). The sample consists of 130 faint, broad-line AGN with redshift up to z=5 and 17.5faint AGN. In this paper we present the measurement of the Optical Luminosity Function up to z=3.6 derived from this sample, we compare our results with previous results from brighter samples both at low and at high redshift and finally, through the estimate of the bolometric luminosity function, we compare them also with the results from X-ray and mid-IR selected samples. Our data, more than one magnitude fainter than previous optical surveys, allow us to constrain the faint part of the luminosity function up to high redshift. A comparison of our data with the 2dF sample at low redshift (1 < z < 2.1) shows that the VVDS data can not be well fitted with the PLE models derived by previous samples. Qualitatively, this appears to be due to the fact that our data suggest the presence of an excess of faint objects at low redshift (1.0faint VVDS sample with the large sample of bright AGN extracted from the SDSS DR3 (Richards et al. 2006b, AJ, 131, 2766) and testing a number of different evolutionary models, we find that the model which better represents the combined luminosity functions, over a wide range of redshift and luminosity, is a luminosity dependent density evolution (LDDE) model, similar to those derived from the major X-surveys. Such a parameterization allows the redshift of the AGN space density peak to change as a function of luminosity and explains the excess of faint AGN that we find at 1.0 < z < 1.5. On the basis of this model we find, for the

  13. 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

  14. Finding faint H I structure in and around galaxies: Scraping the barrel

    NASA Astrophysics Data System (ADS)

    Punzo, D.; van der Hulst, J. M.; Roerdink, J. B. T. M.

    2016-10-01

    Soon to be operational H I survey instruments such as APERTIF and ASKAP will produce large datasets. These surveys will provide information about the H I in and around hundreds of galaxies with a typical signal-to-noise ratio of ∼10 in the inner regions and ∼1 in the outer regions. In addition, such surveys will make it possible to probe faint H I structures, typically located in the vicinity of galaxies, such as extra-planar-gas, tails and filaments. These structures are crucial for understanding galaxy evolution, particularly when they are studied in relation to the local environment. Our aim is to find optimized kernels for the discovery of faint and morphologically complex H I structures. Therefore, using H I data from a variety of galaxies, we explore state-of-the-art filtering algorithms. We show that the intensity-driven gradient filter, due to its adaptive characteristics, is the optimal choice. In fact, this filter requires only minimal tuning of the input parameters to enhance the signal-to-noise ratio of faint components. In addition, it does not degrade the resolution of the high signal-to-noise component of a source. The filtering process must be fast and be embedded in an interactive visualization tool in order to support fast inspection of a large number of sources. To achieve such interactive exploration, we implemented a multi-core CPU (OpenMP) and a GPU (OpenGL) version of this filter in a 3D visualization environment (SlicerAstro).

  15. Faint progenitors of luminous z ∼ 6 quasars: Why do not we see them?

    NASA Astrophysics Data System (ADS)

    Pezzulli, Edwige; Valiante, Rosa; Orofino, Maria C.; Schneider, Raffaella; Gallerani, Simona; Sbarrato, Tullia

    2017-04-01

    Observational searches for faint active nuclei at z > 6 have been extremely elusive, with a few candidates whose high-z nature is still to be confirmed. Interpreting this lack of detections is crucial to improve our understanding of high-z supermassive black holes (SMBHs) formation and growth. In this work, we present a model for the emission of accreting black holes (BHs) in the X-ray band, taking into account super-Eddington accretion, which can be very common in gas-rich systems at high-z. We compute the spectral energy distribution for a sample of active galaxies simulated in a cosmological context, which represent the progenitors of a z ∼ 6 SMBH with MBH ∼ 109 M⊙. We find an average Compton-thick fraction of ∼45 per cent and large typical column densities (NH ≳ 1023 cm2). However, faint progenitors are still luminous enough to be detected in the X-ray band of current surveys. Even accounting for a maximum obscuration effect, the number of detectable BHs is reduced at most by a factor of 2. In our simulated sample, observations of faint quasars are mainly limited by their very low active fraction (fact ∼ 1 per cent), which is the result of short, supercritical growth episodes. We suggest that to detect high-z SMBHs progenitors, large area surveys with shallower sensitivities, such as COSMOS Legacy and XMM-LSS+XXL, are to be preferred with respect to deep surveys probing smaller fields, such as Chandra Deep Field South.

  16. 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.

  17. THE FAINT END OF THE CLUSTER-GALAXY LUMINOSITY FUNCTION AT HIGH REDSHIFT

    SciTech Connect

    Mancone, Conor L.; Baker, Troy; Gonzalez, Anthony H.; Ashby, Matthew L. N.; Snyder, Greg; Stanford, Spencer A.; Brodwin, Mark; Eisenhardt, Peter R. M.; Stern, Daniel; Wright, Edward L.

    2012-12-20

    We measure the faint-end slope of the galaxy luminosity function (LF) for cluster galaxies at 1 < z < 1.5 using Spitzer IRAC data. We investigate whether this slope, {alpha}, differs from that of the field LF at these redshifts, and with the cluster LF at low redshifts. The latter is of particular interest as low-luminosity galaxies are expected to undergo significant evolution. We use seven high-redshift spectroscopically confirmed galaxy clusters drawn from the IRAC Shallow Cluster Survey to measure the cluster-galaxy LF down to depths of M* + 3 (3.6 {mu}m) and M* + 2.5 (4.5 {mu}m). The summed LF at our median cluster redshift (z = 1.35) is well fit by a Schechter distribution with {alpha}{sub 3.6{mu}m} = -0.97 {+-} 0.14 and {alpha}{sub 4.5{mu}m} = -0.91 {+-} 0.28, consistent with a flat faint-end slope and is in agreement with measurements of the field LF in similar bands at these redshifts. A comparison to {alpha} in low-redshift clusters finds no statistically significant evidence of evolution. Combined with past studies which show that M* is passively evolving out to z {approx} 1.3, this means that the shape of the cluster LF is largely in place by z {approx} 1.3. This suggests that the processes that govern the buildup of the mass of low-mass cluster galaxies have no net effect on the faint-end slope of the cluster LF at z {approx}< 1.3.

  18. 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.

  19. 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).

  20. The early faint sun paradox: Organic shielding of ultraviolet-labile greenhouse gases

    SciTech Connect

    Sagan, C.; Chyba, C.

    1997-05-23

    Atmospheric mixing ratios of {approximately}10{sup -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. 78 refs., 2 figs., 1 tab.

  1. 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

  2. Alignment statistics of clusters with their brightest members at bright and faint isophotes

    SciTech Connect

    Struble, M.F.

    1987-06-01

    For a sample of 21 first-ranked cluster galaxies with published isophotal photometry and position angles of these isophotes, it is found that the major axes of both the bright and faint isophotal contours tend to be aligned within about 30 deg of the major axis of the parent cluster. This supports the hypothesis that first-ranked galaxies are formed already aligned with their parent clusters rather than the hypothesis that only outer envelopes which accreted after formation are aligned with the cluster. 21 references.

  3. 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.

  4. Application of digital image processing techniques to faint solar flare phenomena

    NASA Technical Reports Server (NTRS)

    Glackin, D. L.; Martin, S. F.

    1980-01-01

    Digital image processing of eight solar flare events was performed using the Video Information Communication and Retrieval language in order to study moving emission fronts, flare halos, and Moreton waves. The techniques used include contrast enhancement, isointensity contouring, the differencing of images, spatial filtering, and geometrical registration. The spatial extent and temporal behavior of the faint phenomena is examined along with the relation of the three types of phenomena to one another. The image processing techniques make possible the detailed study of the history of the phenomena and provide clues to their physical nature.

  5. First results from the Faint Object Camera - Observations of PKS 0521 - 36

    NASA Technical Reports Server (NTRS)

    Macchetto, F.; Albrecht, R.; Barbieri, C.; Blades, J. C.; Boksenberg, A.

    1991-01-01

    The Faint Object Camera on the Hubble Space Telescope was used to observe the radio galaxy PKS 0521 - 36 which hosts a prominent radio jet. Images of the jet show spatial structure comparable to VLA data and significantly better than optical ground-based observations. The jet structure is resolved at FOC resolution. In addition to the radio knot, well resolved by the FOC, an extension of the jet toward the nucleus is apparent. The rest of the jet does not show much clumpiness, implying that the synchrotron electrons must be accelerated all along the jet to account for the extent in the optical region.

  6. 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.

  7. Boo-1137—an Extremely Metal-Poor Star in the Ultra-Faint Dwarf Spheroidal Galaxy Boötes I

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

    We present high-resolution (R ~ 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) Boötes I, absolute magnitude M V ~ -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 Boötes 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] lsim-3.0. The α-elements Mg, Si, Ca, and Ti are all higher by Δ[X/Fe] ~ 0.2 than the average halo values. Monte Carlo analysis indicates that Δ[α/Fe] values this large are expected with a probability ~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 α-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. Observations obtained for ESO program P383.B-0038, using VLT-UT2/UVES.

  8. TURNING THE TIDES ON THE ULTRA-FAINT DWARF SPHEROIDAL GALAXIES: COMA BERENICES AND URSA MAJOR II

    SciTech Connect

    Munoz, Ricardo R.; Geha, Maria; Willman, Beth E-mail: marla.geha@yale.ed

    2010-07-15

    We present deep CFHT/MegaCam photometry of the ultra-faint Milky Way satellite galaxies: Coma Berenices (ComBer) and Ursa Major II (UMa II). These data extend to r {approx} 25, corresponding to 3 mag below the main-sequence turn-offs in these galaxies. We robustly calculate a total luminosity of M{sub V} = -3.8 {+-} 0.6 for ComBer and M{sub V} = -3.9 {+-} 0.5 for UMa II, in agreement with previous results and confirming that these galaxies are among the faintest of the known dwarf satellites of the Milky Way. ComBer shows a fairly regular morphology with no signs of active tidal stripping down to a surface brightness limit of 32.4 mag arcsec{sup -2}. Using a maximum likelihood analysis, we calculate the half-light radius of ComBer to be r{sub half} = 74 {+-} 4 pc (5.8 {+-} 0.'3) and its ellipticity {epsilon} = 0.36 {+-} 0.04. In contrast, UMa II shows signs of ongoing disruption. We map its morphology down to {mu}{sub V} = 32.6 mag arcsec{sup -2} and found that UMa II is larger than previously determined, extending at least {approx}600 pc (1.{sup 0}1 on the sky) and it is also quite elongated with an overall ellipticity of {epsilon} = 0.50 {+-} 0.2. However, our estimate for the half-light radius, 123 {+-} 3 pc (14.1 {+-} 0.'3) is similar to previous results. We discuss the implications of these findings in the context of potential indirect dark matter detections and galaxy formation. We conclude that while ComBer appears to be a stable dwarf galaxy, UMa II shows signs of ongoing tidal interaction.

  9. Recognizing Sequences of Sequences

    PubMed Central

    Kiebel, Stefan J.; von Kriegstein, Katharina; Daunizeau, Jean; Friston, Karl J.

    2009-01-01

    The brain's decoding of fast sensory streams is currently impossible to emulate, even approximately, with artificial agents. For example, robust speech recognition is relatively easy for humans but exceptionally difficult for artificial speech recognition systems. In this paper, we propose that recognition can be simplified with an internal model of how sensory input is generated, when formulated in a Bayesian framework. We show that a plausible candidate for an internal or generative model is a hierarchy of ‘stable heteroclinic channels’. This model describes continuous dynamics in the environment as a hierarchy of sequences, where slower sequences cause faster sequences. Under this model, online recognition corresponds to the dynamic decoding of causal sequences, giving a representation of the environment with predictive power on several timescales. We illustrate the ensuing decoding or recognition scheme using synthetic sequences of syllables, where syllables are sequences of phonemes and phonemes are sequences of sound-wave modulations. By presenting anomalous stimuli, we find that the resulting recognition dynamics disclose inference at multiple time scales and are reminiscent of neuronal dynamics seen in the real brain. PMID:19680429

  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. Analysis of a Close Pair of Faint Sources Near a Massive Young Star

    NASA Astrophysics Data System (ADS)

    Kamon, Saki; Kraus, Adam L.; Rizzuto, Aaron C.; Ireland, Michael; Carpenter, John M.

    2017-01-01

    Directly imaged exoplanets are rare but important, because they provide a rare glimpse at how planet interiors and atmospheres evolve over time via direct measurement of planetary luminosities and spectra. The details of individual planetary system architectures directly inform our understanding of planet formation and evolution. We present our findings from a high-resolution imaging survey of a nearby star-forming region that indicate the presence of a close pair of faint sources near a massive, A-type young star. From multiple epochs of AO imaging obtained with NIRC2, we test for association of each faint source with the host star via measurement of common proper motion. We also assess whether the sources are two planetary mass objects, or a more massive object obscured by an edge on disk. In the case of two planetary mass objects, we estimate the component masses from their luminosities and colors.We conclude by discussing possible future observations to further determine the nature of this complicated system.

  12. The First Science Flight of the Faint Intergalactic medium Redshifted Emission Balloon (FIREBALL)

    NASA Astrophysics Data System (ADS)

    Martin, Christopher; Milliard, Bruno; Schiminovich, David; Tuttle, Sarah; Matuszewski, Matt; Rahman, Shahin; Evrard, Jean; Frank, Stephan; Deharveng, Jean-Michel; Peroux, Celine

    We have completed the second flight of the path-finding experiment, the Faint Intergalactic medium Redshifted Emission Balloon (FIREBALL), designed to discover and map faint emis-sion from the Intergalactic Medium (IGM). The second flight was fully successful, proving a fully functional fine pointing gondola with arcsec level capability, a 1 meter diameter (fixed) parabola primary telescope with planar sidereostat for pointing, a complete closed loop guide camera and control software, and a fiber fed UV integral field spectrograph feeding a spare GALEX Near UV detector. Three scientific targets were observed, and analysis of the data shows that the instrument performed as expected. The flux measurements obtained will be compared to models for IGM emission. We discuss future modifications to the payload that will achieve a 10-to 30-fold increase in sensitivity over science flight 1. We also discuss other instrument configurations that can utilize the 1-meter UV telescope and arcsecond pointing platform, and their corresponding science objectives. FIREBALL is a collaboration of NASA, Caltech, Columbia University, CNES, and Laboratorie Astrophysique Marseille, and is sup-ported by NASA, CNES, and CNRS.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. The Intensity Distribution of Faint Gamma-Ray Bursts Detected with BATSE

    NASA Technical Reports Server (NTRS)

    Kommers, Jefferson; Lewin, Walter H.; Kouveliotou, Chryssa; vanParadijs, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    1998-01-01

    We have recently completed a search of 6 years of archival Burst and Transient Source Experiment (BATSE) data for gamma-ray bursts (GRBS) that were too faint to activate the real-time burst detection system running onboard the spacecraft. These "non-triggered" bursts can be combined with the "triggered" bursts detected onboard 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 (V/V(max)) statistic (in Euclidean space) for the bursts we detect is 0.177 +/- 0.006. This surprisingly low value is obtained because we detected very few bursts on the 4.096 s and 8.192 s time scales (where most bursts have their highest signal-to-noise ratio) that were not already detected on the 1.024 s time scale. 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. These results lend support to the conclusions of previous studies predicting that relatively few faint bursts are waiting to be found below the BATSE onboard detection threshold.

  20. Star/galaxy separation at faint magnitudes: application to a simulated Dark Energy Survey

    SciTech Connect

    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.

    2015-04-14

    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.

  1. 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.

  2. 2D Emission Line Galaxies in the Faint Infrared Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Pirzkal, Nor; Ryan, Russell E.; Rothberg, Barry; Meurer, Gerhardt R.; Malhotra, Sangeeta; Rhoads, James E.; Koekemoer, Anton M.; Finkelstein, Steven; Grogin, Norman A.

    2015-08-01

    The Faint Infrared Galaxy Survey (FIGS) provides us with a unique opportunity to identify emission line galaxies. Emission lines such as [OII], [OIII], Hα and Lya lines can be identified in the FIGS slitless spectroscopic observations down to faint line fluxes of a few times 10-17 erg/s/cm2. Crucially, the use of multiple observations, taken at different position angles on the sky allows us to accurately determine the location of these star forming regions within individual galaxies using the Emission Line 2D (EM2D) method. Our ability to detect high equivalent width lines independently of any host galaxies allows us to search for naked emission line objects. Combining this method with the wavelength coverage of the G102 grism, we are able to identify emission line objects using [OII] and [OIII], and Hα over 0.2 < z < 2 and using Lyman alpha from 6 < z < 8. Here, we present the first results on star forming galaxies selected using this method and demonstrate the wealth of data to be expected from the FIGS project.

  3. 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.

  4. Red blood cell production

    MedlinePlus

    ... hemocytoblasts give rise to all of the formed elements in blood. If a hemocytoblast commits to becoming a cell called a proerythroblast, it will develop into a new red blood cell. The formation of a red ...

  5. THE DETECTION OF ULTRA-FAINT LOW SURFACE BRIGHTNESS DWARF GALAXIES IN THE VIRGO CLUSTER: A PROBE OF DARK MATTER AND BARYONIC PHYSICS

    SciTech Connect

    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 ≲ μ{sub r} ≲ 26) dwarf galaxy candidates in one deep Virgo field of just 576 arcmin{sup 2} 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 ≲ M{sub r} ≲ −9 and 250 ≲ r{sub s} ≲ 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{sup −11} yr{sup −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 M{sub r} ∼ −9.3 (corresponding to total masses M ∼ 10{sup 7} M{sub ⊙}), 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.

  6. 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

  7. 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.

  8. 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.

  9. 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 ...

  10. Ultraviolet Interstellar Linear Polarization. IV. Cross-Calibration Between the Wisconsin Ultraviolet Photo-Polarimeter Experiment and the Faint Object Spectrograph

    NASA Astrophysics Data System (ADS)

    Wolff, M. J.; Clayton, G. C.; Allen, R. G.; Babler, B. L.; Meade, M. R.; Nordsieck, K. H.; Anderson, C. M.; Martin, P. G.; Whittet, D. C. B.

    1997-05-01

    The Wisconsin Ultraviolet Photo-Polarimeter experiment (WUPPE) and the Faint Object Spectrograph (FOS) started gathering UV spectropolarimetry from space in 1990. Although both instruments are no longer operating, each observed a wide range of polarimetrically interesting objects before being retired. We examined the polarimetric calibration of each instrument and compared the absolute calibrations through the use of the limited sample of ``standard stars'' observed by both instruments. We found: The internal polarization calibration of FOS for the pre- and post-COSTAR eras are consistent within the estimated statistical and systematic errors. The much higher post-COSTAR instrumental polarization is stable and correctable. The internal polarization calibration of WUPPE for Astro-1 and -2 are consistent within the estimated statistical and systematic errors. However, there appears to be some variation in region to the red of 3.5 micron (-1) , where the unpolarized star data show a larger dispersion. This may be related to focus issues. The systematic errors are estimated to be 0.1%+ 0.02p(%) and 0.1%+0.1p(%) for pre- and post-COSTAR datasets, respectively. For WUPPE, the systematic error is 0.05%+0.05p(%). The observations in common between FOS and WUPPE for HD 197770, 161056, and 161961 show that the data can be compared on same basis. Each calibration produces consistent results. This work was supported by NASA grants NAS5-26777, NAG5-3032 and NAG5-3032.

  11. Deep imaging of the field of the z = 4.9 quasar PC 1247+3406, and faint galaxy counts in the K band with the Keck telescope

    NASA Technical Reports Server (NTRS)

    Soifer, B. T.; Matthews, K.; Djorgovski, S.; Larkin, J.; Graham, J. R.; Harrison, W.; Jernigan, G.; Lin, S.; Nelson, J.; Neugebauer, G.

    1994-01-01

    We present deep images in the K(sub s) band of the field of the quasar PC 1247+3406 at z = 4.897, obtained using the near-infrared camera on the W. M. Keck telescope. A number of faint sources have been detected, some of which appear to be quite red. Their nature and redshifts remain uncertain at this time. These data are combined with deep Keck infrared images of five additional fields and present galaxy counts reaching down to K(sub s) = 22 mag, comparable to the deepest K-band surveys to date. The data presented here are in good agreement with the Hawaii Deep Survey and represent the first independent verification of those results. The slope of the log N-log S relation derived from these data agrees well with the Hawaii Deep Survey, while the counts are slightly higher, especially at the faintest levels probed here. This may be due to a presence of groups or clusters around the target objects at high redshifts.

  12. The radio spectral energy distribution of infrared-faint radio sources

    NASA Astrophysics Data System (ADS)

    Herzog, A.; Norris, R. P.; Middelberg, E.; Seymour, N.; Spitler, L. R.; Emonts, B. H. C.; Franzen, T. M. O.; Hunstead, R.; Intema, H. T.; Marvil, J.; Parker, Q. A.; Sirothia, S. K.; Hurley-Walker, N.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Callingham, J. R.; Deshpande, A. A.; Dwarakanath, K. S.; For, B.-Q.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hindson, L.; Johnston-Hollitt, M.; Kapińska, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Oberoi, D.; Offringa, A.; Ord, S. M.; Prabu, T.; Procopio, P.; Udaya Shankar, N.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q.; Bannister, K. W.; Chippendale, A. P.; Harvey-Smith, L.; Heywood, I.; Indermuehle, B.; Popping, A.; Sault, R. J.; Whiting, M. T.

    2016-10-01

    Context. Infrared-faint radio sources (IFRS) are a class of radio-loud (RL) active galactic nuclei (AGN) at high redshifts (z ≥ 1.7) that are characterised by their relative infrared faintness, resulting in enormous radio-to-infrared flux density ratios of up to several thousand. Aims: Because of their optical and infrared faintness, it is very challenging to study IFRS at these wavelengths. However, IFRS are relatively bright in the radio regime with 1.4 GHz flux densities of a few to a few tens of mJy. Therefore, the radio regime is the most promising wavelength regime in which to constrain their nature. We aim to test the hypothesis that IFRS are young AGN, particularly GHz peaked-spectrum (GPS) and compact steep-spectrum (CSS) sources that have a low frequency turnover. Methods: We use the rich radio data set available for the Australia Telescope Large Area Survey fields, covering the frequency range between 150 MHz and 34 GHz with up to 19 wavebands from different telescopes, and build radio spectral energy distributions (SEDs) for 34 IFRS. We then study the radio properties of this class of object with respect to turnover, spectral index, and behaviour towards higher frequencies. We also present the highest-frequency radio observations of an IFRS, observed with the Plateau de Bure Interferometer at 105 GHz, and model the multi-wavelength and radio-far-infrared SED of this source. Results: We find IFRS usually follow single power laws down to observed frequencies of around 150 MHz. Mostly, the radio SEDs are steep (α < -0.8; %), but we also find ultra-steep SEDs (α < -1.3; %). In particular, IFRS show statistically significantly steeper radio SEDs than the broader RL AGN population. Our analysis reveals that the fractions of GPS and CSS sources in the population of IFRS are consistent with the fractions in the broader RL AGN population. We find that at least % of IFRS contain young AGN, although the fraction might be significantly higher as suggested by

  13. Dust and Molecular Gas from the Optically Faint Quasars at z 6

    NASA Astrophysics Data System (ADS)

    Wang, Ran; Carilli, C.; Neri, R.; Riechers, D.; Wagg, J.; Walter, F.; Bertoldi, F.; Omont, A.; Cox, P.; Menten, K.; Fan, X.; Strauss, M.

    2011-01-01

    We present millimeter observations of the twelve z 6 quasars discovered from the SDSS southern survey. These objects are typically one or two magnitudes fainter in the optical (i.e., 20.6 faint quasars at z 6 reveal strong FIR emission from 40 to 60 K warm dust and highly excited molecular gas in the quasar host galaxies. The molecular gas masses of the two CO detections are all about 10^10 Msun, which are comparable to that of the CO-detected optically bright quasars at z 6. Their FIR-to-CO luminosity ratios are also consistent with that of the previous CO-detected quasars at z 2 to 6 and the dusty starbusrt systems, e.g., the submillimeter galaxies. However, their FIR-to-UV luminosity ratios are higher than that of the millimeter-detected optically bright quasars at z 6. This confirms the shallow nonlinear FIR-to-AGN luminosity relationship found with other AGN-starburst systems at local and high-z universe. All these results suggest massive star formation coeval with rapid black hole accretion in the host galaxies of the millimeter-detected optically faint quasars at z 6. Further high-resolution imaging of the Molecular CO emission (e.g., with ALMA) will be important to measure the dynamical masses of the spheroidal hosts and understand the black hole-bulge relationship of the optically faint quasars at the earliest epoch.

  14. 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.

  15. The Faint-End Slopes of Galaxy Luminosity Functions in the COSMOS Field

    NASA Astrophysics Data System (ADS)

    Liu, Charles T.; Capak, Peter; Mobasher, Bahram; Paglione, Timothy A. D.; Rich, R. Michael; Scoville, Nicholas Z.; Tribiano, Shana M.; Tyson, Neil D.

    2008-01-01

    We examine the faint-end slope of the rest-frame V-band luminosity function (LF), with respect to galaxy spectral type, of field galaxies with redshift z < 0.5, using a sample of 80,820 galaxies with photometric redshifts in the 2 deg2 Cosmic Evolution Survey (COSMOS) field. For all galaxy spectral types combined, the LF slope ranges from -1.24 to -1.12, from the lowest redshift bin to the highest. In the lowest redshift bin (0.02 < z < 0.1), where the magnitude limit is MVlesssim - 13, the slope ranges from α ~ - 1.1 for galaxies with early-type spectral energy distributions (SEDs) to α ~ - 1.9 for galaxies with low-extinction starburst SEDs. In each galaxy SED category (early-type, Sbc, Scd+Irr, and starburst), the faint-end slopes grow shallower with increasing redshift; in the highest redshift bin (0.4 < z < 0.5), α ~ - 0.5 and -1.3 for early types and starbursts, respectively. The steepness of α at lower redshifts could be qualitatively explained by LF evolution, or by large numbers of faint dwarf galaxies, perhaps of low surface brightness, that are not detected at higher redshifts. Based on observations 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 (AURA), Inc., under NASA contract NAS 5-26555; also based on data collected at Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and the National Optical Astronomy Observatory, which are operated by AURA, Inc., under cooperative agreement with the National Science Foundation; at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA; at the European Southern Observatory under Large Program 175.A-0839, Chile; at the Canada-France-Hawaii Telescope with MegaPrime/MegaCam, operated as a joint project by the CFHT

  16. 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.

  17. 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.

  18. Spectra of faint sources in crowded fields with FRODOSpec on the Liverpool Robotic Telescope

    NASA Astrophysics Data System (ADS)

    Shalyapin, V. N.; Goicoechea, L. J.

    We check the performance of the FRODOSpec integral-field spectrograph for observations of faint sources in crowded fields. Although the standard processing pipeline L2 yields too noisy fibre spectra, we present a new processing software (L2LENS) that gives rise to accurate spectra for the two images of the gravitationally lensed quasar Q0957+561. Among other things, this L2LENS reduction tool accounts for the presence of cosmic-ray events, scattered-light backgrounds, blended sources, and chromatic source displacements due to differential atmospheric refraction. Our non-standard reduction of Q0957+561 data shows the ability of FRODOSpec to provide useful information on a wide variety of targets, and thus, the big potential of integral-field spectrographs on current and future robotic telescopes.

  19. Cosmic reionization on computers: The faint end of the galaxy luminosity function

    DOE PAGES

    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

  20. Cosmic reionization on computers: The faint end of the galaxy luminosity function

    SciTech Connect

    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 $z\\gtrsim 6$. 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.

  1. 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.

  2. 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.

  3. 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.

  4. EVIDENCE FOR INFRARED-FAINT RADIO SOURCES AS z > 1 RADIO-LOUD ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Huynh, Minh T.; Norris, Ray P.; Siana, Brian; Middelberg, Enno

    2010-02-10

    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 {mu}m) 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 {approx}> 1) active galactic nuclei.

  5. 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.

  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. Discovery of a Type Ia Supernova in a Faint Dwarf Galaxy

    NASA Astrophysics Data System (ADS)

    Williams, R.; Hsiao, E. Y.; Mahabal, A.; Djorgovski, S. G.; Drake, A. J.; Graham, M. J.; Graham, M. L.; Pritchet, C. J.; Parker, A.; Sadavoy, S.; Balam, D.; Catelan, M.; Beshore, E. C.; Larson, S. M.; Boattini, A.; Christensen, E.

    2008-11-01

    We have discovered a supernova in observations from CSS, Palomar 60 and the Plaskett Telescope starting from 22 Nov UT. The discovery has the following parameters:

    CSS081122:094326+251021 2008-11-22 UT 10:18:11 RA 09:43:26.22 Dec 25:10:21.9 Mag 16.4 Type SN Iaz=0.027
    CSS081122:094326+251021 is associated with a very faint anonymous galaxy seen in SDSS DR7 images (mags: u= 23.2, g=22.7, r=22.8, i=22.7, z=23.6).

  8. Starburst and AGN Indicators in Optically Faint X-ray Sources in the Cosmic Evolution Survey

    NASA Astrophysics Data System (ADS)

    Robins, Derek; Elvis, M.; Civano, F.

    2011-01-01

    A sample of 55 faint, X-ray selected objects were chosen for analysis from the COSMOS survey with high quality Keck DEIMOS data. The average redshift of the sample was 1.36, consistent with the average redshift of type 1 AGN in COSMOS of 1.4. Emission lines, NeV - an indicator of AGN luminosity - and OII - an indicator of star formation rate, were measured for a subset of 34 objects. Line properties for these objects were measured. The combination of the two lines is evidence for significant star formation in these obscured AGN. Differences between OII and NeV redshifts were measured carefully. Significant differences between OII and NeV redshifts were found in 10-14 objects, implying OII outflows. The results are consistent with current models of galaxy evolution that invoke an interplay between AGN activity and star formation.

  9. A redshift limit for the faint blue galaxy population from deep U band imaging

    SciTech Connect

    Guhathakurta, P.; Tyson, J.A.; Majewski, S.R. AT T Bell Laboratories, Murray Hill, NJ Yerkes Observatory, Williams Bay, WI )

    1990-07-01

    A definitive upper limit for the redshift of the population of faint blue galaxies found in deep imaging surveys is obtained. The U-B(j), and particularly the B(j)-R, colors of these objects show a blueing trend toward fainter magnitudes. A typical galaxy at R = 26 has colors that are only slightly redder than a flat spectrum. For any reasonable Lyman limit break, this constrains 93 percent or more of the galaxies to under z about 3, beyond which the break gets redshifted through the U band. The galaxies appear to be undergoing relatively recent evolution with rest frame spectra that are approximately flat down to the Lyman limit. 23 refs.

  10. 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.

  11. 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.

  12. A review of the genus Pempheris (Perciformes, Pempheridae) of the Red Sea, with description of a new species.

    PubMed

    Koeda, Keita; Yoshino, Tetsuo; Imai, Hideyuki; Tachihara, Katsunori

    2014-04-30

    Mauritius, one is designated as the lectotype, the other is re-identified as P. mangula; P. nesogallica is presently known only from the southern Red Sea. This species has a similar morphology to P. mangula, but can be distinguished by a smaller eye than P. mangula, and lack irregular faint longitudinal light stripes on the body side. Pempheris tominagai are distinguished from P. schwenkii Bleeker 1855, formerly misidentified, by the form of posterior nostril, scale counts, color of caudal fin, and by a 2.1% mitochondrial DNA sequence divergence. 

  13. The VIMOS VLT Deep Survey: the faint type-1 AGN sample

    NASA Astrophysics Data System (ADS)

    Gavignaud, I.; Bongiorno, A.; Paltani, S.; Mathez, G.; Zamorani, G.; Møller, P.; Picat, J. P.; Le Brun, V.; Marano, B.; Le Fèvre, O.; Bottini, D.; Garilli, B.; Maccagni, D.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnaboldi, M.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Cappi, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Guzzo, L.; Ilbert, O.; Iovino, A.; McCracken, H. J.; Marinoni, C.; Mazure, A.; Meneux, B.; Merighi, R.; Pellò, R.; Pollo, A.; Pozzetti, L.; Radovich, M.; Zucca, E.; Bondi, M.; Busarello, G.; Cucciati, O.; de la Torre, S.; Gregorini, L.; Lamareille, F.; Mellier, Y.; Merluzzi, P.; Ripepi, V.; Rizzo, D.; Vergani, D.

    2006-10-01

    We present the type-1 active galactic nuclei (AGN) sample extracted from the VIMOS VLT Deep Survey's first observations of 21 000 spectra in 1.75 deg^2. This sample, which is purely magnitude-limited and free of morphological or color-selection biases, contains 130 broad-line AGN (BLAGN) spectra with redshift up to 5. Our data are divided into a wide (I_AB ≤ 22.5) and a deep (I_AB ≤ 24) subsample containing 56 and 74 objects, respectively. Because of its depth and selection criteria, this sample is uniquely suited for studying the population of faint type-1 AGN. Our measured surface density (~472 ± 48 BLAGN per square degree with I_AB ≤ 24) is significantly higher than that of any other optically selected sample of BLAGN with spectroscopic confirmation. By applying a morphological and color analysis to our AGN sample, we find that (1) ~23 % of the AGN brighter than I_AB=22.5 are classified as extended, and this percentage increases to ~42% for those with z < 1.6; (2) a non-negligible fraction of our BLAGN are lying close to the color-space area occupied by stars in the u^*-g' versus g'-r' color-color diagram. This leads us to the conclusion that the classical optical-ultraviolet preselection technique, if employed at such deep magnitudes (I_AB=22.5) in conjuction with a preselection of point-like sources, can miss up to ~35% of the AGN population. Finally, we present a composite spectrum of our sample of objects. While the continuum shape is very similar to that of the SDSS composite at short wavelengths, it is much redder than that of the SDSS composite at λ ≥ 3000 Å. We interpret this as due to significant contamination from emission of the host galaxies, as expected from the faint absolute magnitudes sampled by our survey.

  14. Infrared-faint radio sources in the SERVS deep fields. Pinpointing AGNs at high redshift

    NASA Astrophysics Data System (ADS)

    Maini, A.; Prandoni, I.; Norris, R. P.; Spitler, L. R.; Mignano, A.; Lacy, M.; Morganti, R.

    2016-12-01

    Context. Infrared-faint radio sources (IFRS) represent an unexpected class of objects which are relatively bright at radio wavelength, but unusually faint at infrared (IR) and optical wavelengths. A recent and extensive campaign on the radio-brightest IFRSs (S1.4 GHz≳ 10 mJy) has provided evidence that most of them (if not all) contain an active galactic nuclei (AGN). Still uncertain is the nature of the radio-faintest IFRSs (S1.4 GHz≲ 1 mJy). Aims: The scope of this paper is to assess the nature of the radio-faintest IFRSs, testing their classification and improving the knowledge of their IR properties by making use of the most sensitive IR survey available so far: the Spitzer Extragalactic Representative Volume Survey (SERVS). We also explore how the criteria of IFRSs can be fine-tuned to pinpoint radio-loud AGNs at very high redshift (z > 4). Methods: We analysed a number of IFRS samples identified in SERVS fields, including a new sample (21 sources) extracted from the Lockman Hole. 3.6 and 4.5 μm IR counterparts of the 64 sources located in the SERVS fields were searched for and, when detected, their IR properties were studied. Results: We compared the radio/IR properties of the IR-detected IFRSs with those expected for a number of known classes of objects. We found that IR-detected IFRSs are mostly consistent with a mixture of high-redshift (z ≳ 3) radio-loud AGNs. The faintest ones (S1.4 GHz 100 μJy), however, could be also associated with nearer (z 2) dust-enshrouded star-burst galaxies. We also argue that, while IFRSs with radio-to-IR ratios >500 can very efficiently pinpoint radio-loud AGNs at redshift 2 < z < 4, lower radio-to-IR ratios ( 100-200) are expected for higher redshift radio-loud AGNs.

  15. 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.

  16. 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.

  17. The Discovery of an Ultra-faint Star Cluster in the Constellation of Ursa Minor

    NASA Astrophysics Data System (ADS)

    Muñoz, R. R.; Geha, M.; Côté, P.; Vargas, L. C.; Santana, F. A.; Stetson, P.; 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, Muñoz 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 0farcm5, or equivalently 7 pc, and an ellipticity consistent with being zero. We estimate its absolute magnitude to be MV = -0.4 ± 0.9, which corresponds to LV = 120+160 -65 L ⊙ and we measure a heliocentric radial velocity of -137 ± 4 km s-1 based on Keck/DEIMOS spectroscopy. This new satellite is separate from Ursa Minor by ~30 kpc and 110 km s-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 Muñoz 1 is a new ultra-faint stellar cluster. Along with Segue 3 this is one of the faintest stellar clusters known to date. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. Spectroscopic 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.

  18. A Keck Search for Faint Satellites of Pluto in Support of New Horizons

    NASA Astrophysics Data System (ADS)

    Merline, William J.; Weaver, H. A.; Tamblyn, P. M.; Neyman, C.; Stern, S. A.; Carry, B.; Spencer, J. R.; Conrad, A. R.; Showalter, M. A.; Olkin, C. B.; Steffl, A. J.; Sheppard, S. S.; Buie, M. W.; Enke, B. L.

    2012-10-01

    We report on our efforts to search for faint satellites of Pluto using Keck 2 adaptive optics (AO). Last year, using HST, Showalter et al. 2011 (IAUC 9221) discovered a new, faint satellite ("P4") around Pluto, demonstrating that Pluto is even richer with orbiting material than was thought previously. That discovery led to speculations that these small satellites could be a source of debris (from random impacts) that could pose a hazard to the New Horizons (NH) spacecraft during its 2015 Pluto flyby. The ejecta would form a cloud around Pluto. The NH project began an aggressive program of HST- and ground-based studies to identify additional as-yet-unseen satellites or debris rings in the system. Only several days into their campaign, a 5th satellite "P5" was discovered with HST (Showalter et al. 2012, IAUC 9253). The output of these studies will be used to plan a contingency ("safe-haven") trajectory through the system. The Keck observations support and complement the new HST observations. Real objects in the HST images may be hidden by bad pixels or diffraction spikes, and Keck may have advantages in some regions of parameter space, such as interior to Charon. r Observing in a near-IR band, the Keck imaging provides additional constraints on the objects, but this makes the observations particularly challenging because of the sky brightness. We have made an effort to optimize the Keck AO observations. Near-IR imaging requires tradeoffs between sky brightness and post-correction Strehl. Expectations and our early results favor H-band in typical conditions. Contrary to prior experience with V 14 targets, we find Laser-Guide-Star AO correction to be far more effective than using Pluto as the wavefront source (NGS). We have achieved imaging that could detect satellites smaller than Nix at good S/N, even in a relatively short (15 min) span.

  19. Photometric and spectroscopic study of the ultra-faint Milky Way satellite Pegasus III

    NASA Astrophysics Data System (ADS)

    Kim, Dongwon; Jerjen, Helmut; Geha, Marla C.; Chiti, Anirudh; Milone, Antonino; Da Costa, Gary S.; Mackey, Dougal; Frebel, Anna; Conn, Blair

    2017-01-01

    Pegasus III (Peg III) is one of the few known ultra-faint dwarf (UFD) satellite galaxies in the outer halo (R >150 kpc) of the Milky Way (MW). We present results from a recent study of Peg III using Magellan/IMACS and Keck/DEIMOS. Our newly-measured structural parameters confirm that Peg III is large (rh = 53±14pc), elongated (∈ = 0.38+0.22-0.38 ), and faint (MV=-3.4±0.4 mag) — indicative of its nature as a dwarf rather than a globular cluster. In the color-magnitude diagram, Peg III is well described by an old (>12Gyr) and metal-poor ([Fe/H]<-2.0 dex) stellar population at a heliocentric distance of 215±12 kpc. Using spectroscopic measurements of individual stars, we identify seven kinematic members of Peg III. The Ca II triplet lines of the brightest members verify that Peg III indeed contains stars with metallicity as low as [Fe/H]=-2.55±0.15 dex. The systemic velocity and velocity dispersion of Peg III are -222.9±2.6 km/s and 5.4+3.0-2.5 km/s, respectively. The inferred dynamical mass within the half-light radius of 1.4+3.0-1.1×106M⊙, and the mass-to-light ratio of M/LV = 1470+5660-1240M⊙/L⊙ provide further evidence that Peg III is a bona fide UFD. Peg III and another distant UFD Pisces II lie relatively close to each other (△dspatial=43±19 kpc) and share similar systemic radial velocities (△vGSR=12.3±3.7 km/s), which suggests that they may share a common origin.

  20. 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; vanParadus, Jan; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.

    2000-01-01

    We have recently completed a search of six years of archival Burst and Transient Source Experiment (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 two lower than could be studied previously. The value of the statistic (in Euclidean space) for the bursts we detect is 0.177 +/- 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 Ib/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.

  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. The role of cognitions, trait anxiety and disgust sensitivity in generating faintness around blood-injury phobic stimuli.

    PubMed

    Exeter-Kent, Holly A; Page, Andrew C

    2006-03-01

    The effects on blood-injury fear and fainting of scripts concerning pain, nausea, and anger and individual differences in trait anxiety and disgust sensitivity were investigated. Eighteen participants were high in disgust sensitivity and trait anxiety, 11 were low in disgust sensitivity but high in trait anxiety, 10 were high in disgust sensitivity but low in trait anxiety, and 16 were low in disgust sensitivity and trait anxiety. Participants were exposed to pain, nausea, and anger scripts during presentation of blood-injury slides. The ability of the scripts to increase symptoms of fear and faintness, on a state version of the Blood-Injection Symptom Scale (BISS; Page, A. C., Bennett, K. S., Carter, O., Smith, J., & Woodmore, K. (1997). Blood-Injection Symptom Scale (BISS): Assessing the structure of phobic symptomatology elicited by blood and injections. Behaviour Research and Therapy, 35, 457-464) were examined. Analyses indicated that individual differences in trait anxiety and disgust sensitivity interact to generate symptoms of faintness when the pain script was read. That is, disgust sensitive and trait anxious participants reported greater faintness relative to other conditions. The implications for theory and treatment of blood-injury-injection phobia are discussed.

  3. 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.

  4. 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

  5. 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.

  6. Red giants: then and now

    NASA Astrophysics Data System (ADS)

    Faulkner, John

    Fred Hoyle's work on the structure and evolution of red giants, particularly his pathbreaking contribution with Martin Schwarzschild (Hoyle and Schwarzschild 1955), is both lauded and critically assessed. In his later lectures and work with students in the early 1960s, Hoyle presented more physical ways of understanding some of the approximations used, and results obtained, in that seminal paper. Although later ideas by other investigators will be touched upon, Hoyle's viewpoint - that low-mass red giants are essentially white dwarfs with a serious mass-storage problem - is still extremely fruitful. Over the years, I have further developed his method of attack. Relatively recently, I have been able to deepen and broaden the approach, finally extending the theory to provide a unifying treatment of the structure of low-mass stars from the main sequence though both the red-giant and horizontal-branch phases of evolution. Many aspects of these stars that had remained puzzling, even mysterious, for decades have now fallen into place, and some questions have been answered that were not even posed before. With low-mass red giants as the simplest example, this recent work emphasizes that stars, in general, may have at least two distinct but very important centres: (I) a geometrical centre, and (II) a separate nuclear centre, residing in a shell outside a zero-luminosity dense core for example. This two-centre perspective leads to an explicit, analytical, asymptotic theory of low-mass red-giant structure. It enables one to appreciate that the problem of understanding why such stars become red giants is one of anticipating a remarkable yet natural structural bifurcation that occurs in them. This bifurcation occurs because of a combination of known and understandable facts just summarized namely that, following central hydrogen exhaustion, a thin nuclear-burning shell does develop outside a more-or-less dense core. In the resulting theory, both ρsh/ρolinec and

  7. Faint star studies in the magellanic clouds. II. Field regions 9/sup 0/ northeast of the large magellanic cloud bar

    SciTech Connect

    Stryker, L.L.

    1984-06-01

    Photographic photometry is reported for 16 halo field regions. These fields lie 9./sup 0/1 northeast of the LMC bar, surrounding the old globular cluster NGC 2257. Field color-magnitude diagrams show a red horizontal branch, a subgiant branch redder than that of the cluster, and a profusion of blue stars delineating a younger main-sequence. Possible sources of the blue stars are discussed. The field is significantly younger than the cluster, showing that star formation, even in the outer regions of the LMC where the gas density is presently minimal, proceeded long after the formation of the old clusters. It appears that the major portion of stars in the LMC is of intermediate age. That this is true of a region 9 kpc from the bar is of great importance to the eventual derivation of a global history of star formation in the LMC.

  8. 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

  9. 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

  10. 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…

  11. Open clusters rich in red supergiants

    NASA Astrophysics Data System (ADS)

    Negueruela, Ignacio

    2015-08-01

    In the past few years, several clusters containing large numbers of red supergiants have been discovered. These clusters are amongst the most massive young clusters known in the Milky Way, with stellar masses reaching a few tens of thousands of solar masses. They have provided us, for the first time, with large homogeneous samples of red supergiants of a given age. These large populations make them, despite heavy extinction along their sightlines, powerful laboratories to understand the evolutionary status of red supergiants. While some of the clusters, such as the eponymous RSGC1, are so obscured that their members are only observable in the near-IR, at least van der Bergh-Hagen 222 is observable even in the U band, allowing for an excellent characterisation of cluster and stellar properties. The information gleaned so far from these clusters gives strong support to the idea that late-M type supergiants represent a separate class, characterised by very heavy mass loss. It also shows that the spectral-type distribution of red supergiants in the Milky Way is very strongly peaked towards M1, while providing strong hints about the possible evolutionary sequence of red supergiants. In addition, the clusters of red supergiants represent ideal tools to study metallicity in the inner regions of the Milky Way.

  12. 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.

  13. Whole-Genome Sequence Analysis of Bombella intestini LMG 28161T, a Novel Acetic Acid Bacterium Isolated from the Crop of a Red-Tailed Bumble Bee, Bombus lapidarius

    PubMed Central

    Li, Leilei; Illeghems, Koen; Van Kerrebroeck, Simon; Borremans, Wim; Cleenwerck, Ilse; Smagghe, Guy; De Vuyst, Luc

    2016-01-01

    The whole-genome sequence of Bombella intestini LMG 28161T, an endosymbiotic acetic acid bacterium (AAB) occurring in bumble bees, was determined to investigate the molecular mechanisms underlying its metabolic capabilities. The draft genome sequence of B. intestini LMG 28161T was 2.02 Mb. Metabolic carbohydrate pathways were in agreement with the metabolite analyses of fermentation experiments and revealed its oxidative capacity towards sucrose, D-glucose, D-fructose and D-mannitol, but not ethanol and glycerol. The results of the fermentation experiments also demonstrated that the lack of effective aeration in small-scale carbohydrate consumption experiments may be responsible for the lack of reproducibility of such results in taxonomic studies of AAB. Finally, compared to the genome sequences of its nearest phylogenetic neighbor and of three other insect associated AAB strains, the B. intestini LMG 28161T genome lost 69 orthologs and included 89 unique genes. Although many of the latter were hypothetical they also included several type IV secretion system proteins, amino acid transporter/permeases and membrane proteins which might play a role in the interaction with the bumble bee host. PMID:27851750

  14. 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)

  15. Genome Sequencing.

    PubMed

    Verma, Mansi; Kulshrestha, Samarth; Puri, Ayush

    2017-01-01

    Genome sequencing is an important step toward correlating genotypes with phenotypic characters. Sequencing technologies are important in many fields in the life sciences, including functional genomics, transcriptomics, oncology, evolutionary biology, forensic sciences, and many more. The era of sequencing has been divided into three generations. First generation sequencing involved sequencing by synthesis (Sanger sequencing) and sequencing by cleavage (Maxam-Gilbert sequencing). Sanger sequencing led to the completion of various genome sequences (including human) and provided the foundation for development of other sequencing technologies. Since then, various techniques have been developed which can overcome some of the limitations of Sanger sequencing. These techniques are collectively known as "Next-generation sequencing" (NGS), and are further classified into second and third generation technologies. Although NGS methods have many advantages in terms of speed, cost, and parallelism, the accuracy and read length of Sanger sequencing is still superior and has confined the use of NGS mainly to resequencing genomes. Consequently, there is a continuing need to develop improved real time sequencing techniques. This chapter reviews some of the options currently available and provides a generic workflow for sequencing a genome.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. T he Faint Drifting Decameter Radio Bursts From The Solar Corona

    NASA Astrophysics Data System (ADS)

    Briand, C.; Zaslavsky, A.; Lecacheux, A.; Zarka, P.; Maksimovic, M.; Mangeney, A.

    2007-01-01

    The radio observations of solar corona at decameter wavelengths reveal the presence of numerous faint, frequency drifting structures. We analyse observations performed on July 13th , 2002 with the DSP wideband spectrometer instrument implemented at the UTR-2 radiote- lescope. The main characteristics of these structures are statistically studied. Three populations of bursts are iden- tifies. The largest one presents negative frequency drifts of about -0.89 MHz.s-1 and a lifetime extending up to 11 sec (median value 2.72 sec). A second one shows positive frequency drifts of about +0.95 MHz.s-1 and a life- time extending up to 3 sec. The last population consists in structures with very small frequency drifts of about -0.1 MHz.s-1 and a shorter lifetime (about 1 sec). Assuming that those emissions are the signature of elec- tron beams propagating through the solar corona, we deduce that they have a velocity of about 3-5 times the electron thermal velocity. A new mechanism is proposed to explain the formation of plasma waves with such low beam velocity: spatially localized, temporal fluctuations of the electron distribution function width (heating).

  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 OLD ENVIRONMENT OF THE FAINT CALCIUM-RICH SUPERNOVA SN 2005cz

    SciTech Connect

    Perets, Hagai B.; Gal-yam, Avishay; Crockett, R. Mark; Sullivan, Mark; Anderson, Joseph P.; James, Phil A.; Neill, James D.; Leonard, Douglas C.

    2011-02-20

    The supernova SN 2005cz has recently attracted some attention due to the fact that it was spectroscopically similar to type Ib supernovae (SNe Ib), a class that is presumed to result from the core collapse of massive stars, yet it occurred in an elliptical galaxy, where one expects very few massive stars to exist. Two explanations for this remarkable event were put forward. Perets et al. associate SN 2005cz with the class of Ca-rich, faint SNe Ib, which likely result from old double-white-dwarf systems with an He-rich secondary. On the other hand, Kawabata et al. suggest that SN 2005cz is indeed a core-collapse event (in a binary system), albeit of a star at the lower end of the mass range, 10-12 M{sub sun}. The existence of this star in its elliptical host is explained as resulting from low-level star formation (SF) activity in that galaxy. Here we present extensive observations of the location of SN 2005cz, sensitive to a variety of SF tracers, including optical spectroscopy, H{alpha} emission, UV emission, and Hubble Space Telescope photometry. We show that NGC 4589, the host galaxy of SN 2005cz, does not show any signatures of a young stellar population or recent SF activity either close to or far from the location of SN 2005cz.

  4. 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.

  5. A catalog of 7000 optically faint periodic variable stars from the LINEAR survey

    NASA Astrophysics Data System (ADS)

    Ivezic, Zeljko; Palaversa, L.; Sesar, B.; Stuart, J.

    2014-01-01

    We present a catalog of about 7000 optically faint periodic variable stars with light curves obtained by the asteroid survey LINEAR across 10,000 sq.deg. of the northern sky. The majority of these variables have not been cataloged yet. The sample flux limit is several magnitudes fainter than most other wide-angle surveys; the photometric errors range from 0.03 mag at r = 15 to 0.20 mag at r = 18. Light curves include on average 250 data points, collected over about a decade. The sample is dominated by 3900 RR Lyrae stars and 2700 eclipsing binary stars of all subtypes and includes small fractions of relatively rare populations such as asymptotic giant branch stars and SX Phoenicis stars. These publicly available (from https://astroweb.lanl.gov/lineardb/) large samples of robustly classified variable stars will enable detailed statistical studies of the Galactic structure and physics of binary and other stars, and can be used for training automated light curve classification methods. Details about this catalog are available in Palaversa et al. (2013, AJ 146, 101).

  6. The Dark Matter Content of the Triangulum II Ultra-Faint Dwarf Galaxy

    NASA Astrophysics Data System (ADS)

    Kirby, Evan N.; Cohen, Judith G.; Simon, Joshua D.

    2017-01-01

    Triangulum II is an ultra-faint galaxy with a luminosity of 450 L⊙ discovered through Pan-STARRS imaging in 2015. Since then, two independent studies—including one of our own—based on Keck/DEIMOS spectroscopy found that the galaxy has a stellar velocity dispersion of about 5 km/s, indicating a very high concentration of dark matter. Here, we present additional DEIMOS observations over six epochs. We show that a combination of radial velocity variability (likely due to binarity) and inaccuracies in the previous measurements led to a spurious detection of a velocity dispersion in excess of what would be expected from the stellar population alone. Instead, we place an upper limits of 3.4 km/s (90% C.L.) and 4.3 km/s (95% C.L.) on the velocity dispersion. While these limits are compatible with very high mass-to-light ratios (1700 at 90% C.L. or 2600 at 95% C.L.), Triangulum II no longer seems extreme compared to dwarf galaxies of similar luminosity. Because the stars still span a large range of metallicity (-2.8 < [Fe/H] < -1.5), the galactic nature of Triangulum II is not in dispute.

  7. 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.

  8. 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 1574 spectra, obtained with the Hectospec spectrograph on the MMT Observatory (MMTO), to detect Lyman alpha emitters near z ~ 2.7. 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 649 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 at detecting faint sources is dependent on the accuracy of the sky subtraction.

  9. Isophotal Shapes of Early-type Galaxies to Very Faint Levels

    NASA Astrophysics Data System (ADS)

    Chaware, Laxmikant; Cannon, Russell; Kembhavi, Ajit K.; Mahabal, Ashish; Pandey, S. K.

    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.

  10. 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.

  11. 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.

  12. Ultra faint dwarf galaxies: an arena for testing dark matter versus modified gravity

    NASA Astrophysics Data System (ADS)

    Lin, Weikang; Ishak, Mustapha

    2016-10-01

    The scenario consistent with a wealth of observations for the missing mass problem is that of weakly interacting dark matter particles. However, arguments or proposals for a Newtonian or relativistic modified gravity scenario continue to be made. A distinguishing characteristic between the two scenarios is that dark matter particles can produce a gravitational effect, in principle, without the need of baryons while this is not the case for the modified gravity scenario where such an effect must be correlated with the amount of baryonic matter. We consider here ultra-faint dwarf (UFD) galaxies as a promising arena to test the two scenarios based on the above assertion. We compare the correlation of the luminosity with the velocity dispersion between samples of UFD and non-UFD galaxies, finding a significant loss of correlation for UFD galaxies. For example, we find for 28 non-UFD galaxies a strong correlation coefficient of -0.688 which drops to -0.077 for the 23 UFD galaxies. Incoming and future data will determine whether the observed stochasticity for UFD galaxies is physical or due to systematics in the data. Such a loss of correlation (if it is to persist) is possible and consistent with the dark matter scenario for UFD galaxies but would constitute a new challenge for the modified gravity scenario.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Investigation of Faint Galactic Carbon Stars from the First Byurakan Spectral Sky Survey

    NASA Astrophysics Data System (ADS)

    Kostandyan, G. R.; Gigoyan, K. S.

    2016-09-01

    The goal of this paper is to present the optical variability study of the comparatively faint carbon (C) stars which have been discovered by searching the First Byurakan Survey (FBS) low-resolution (lr) spectral plates at high Galactic latitudes using a recent wide-area variability databases. The light curves from the Catalina Sky Survey (CSS) and Northern Sky Variability Survey (NSVS) databases were exploited to study the variability nature of them. From the 120 detected objects 54 are N-type Asymptotic Giant Branch (AGB) C stars. 9 stars belongs to the group of Mira-type, 43 are Semi-Regular (SR), and 2 stars are Irregular (Irr) - type variables. The variability types of 27 objects has been established for the first time. From 66 objects showing early-type spectra 57 are CH-type stars, 4 objects are R-type stars and 5 are dC candidates. K-band absolute magnitudes, distances, and height from the Galactic plane were estimated for all of them. We aim to better understand the nature of the selected C stars through spectroscopy, 2MASS photometric colours, and variability data.

  20. 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.

  1. Discovery of a faint, star-forming, multiply lensed, Lyman-α blob

    NASA Astrophysics Data System (ADS)

    Caminha, G. B.; Karman, W.; Rosati, P.; Caputi, K. I.; Arrigoni Battaia, F.; Balestra, I.; Grillo, C.; Mercurio, A.; Nonino, M.; Vanzella, E.

    2016-11-01

    We report the discovery of a multiply lensed Lyman-α blob (LAB) behind the galaxy cluster AS1063 using the Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT). The background source is at z = 3.117 and is intrinsically faint compared to almost all previously reported LABs. We used our highly precise strong lensing model to reconstruct the source properties, and we find an intrinsic luminosity of LLyα = 1.9 × 1042 erg s-1, extending to 33 kpc. We find that the LAB is associated with a group of galaxies, and possibly a protocluster, in agreement with previous studies that find LABs in overdensities. In addition to Lyman-α (Lyα) emission, we find C iv, He ii, and O iii] ultraviolet (UV) emission lines arising from the centre of the nebula. We used the compactness of these lines in combination with the line ratios to conclude that the Lyα nebula is likely powered by embedded star formation. Resonant scattering of the Lyα photons then produces the extended shape of the emission. Thanks to the combined power of MUSE and strong gravitational lensing, we are now able to probe the circumgalatic medium of sub-L∗ galaxies at z ≈ 3.

  2. 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.

  3. 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.

  4. Thermal balance qualification testing of the thermal control system of the Faint Object Camera

    NASA Astrophysics Data System (ADS)

    Jaekel, E.; Best, R.; Camus, J. P.; Soulat, G.

    1982-06-01

    The stringent image stability requirements (better than 6.5 microns) on the Faint Object Camera (FOC) on the Space Telescope necessitate an active thermal control system to provide for the stability of the optical bench, optical heads and detector head unit during data acquisition. The paper presents results of the thermal performance testing of the FOC thermal control system under simulated flight conditions. The Structure Thermal Module of the FOC, which includes an arrangement of computer-controlled heaters, multi-layer insulation and radiators to provide for thermal stability, was tested in environments corresponding to transient initial deployment without power, steady-state operation in a fixed power mode, a cold hold mode, warm-up from hold to cold operation, transition from cold to intermediate operation, and hot operation. Measurements of image displacement and temperature variations demonstrate that the control system can easily achieve the specified image stability, long-term temperature stability at 17 + or - 2 C, and short-term temperature stability to within less than 0.25 C.

  5. Ultraviolet to optical diffuse sky emission as seen by the Hubble Space Telescope Faint Object Spectrograph

    NASA Astrophysics Data System (ADS)

    Kawara, Kimiaki; Matsuoka, Yoshiki; Sano, Kei; Brandt, Timothy D.; Sameshima, Hiroaki; Tsumura, Kohji; Oyabu, Shinki; Ienaka, Nobuyuki

    2017-02-01

    We present an analysis of the blank-sky spectra observed with the Faint Object Spectrograph on board the Hubble Space Telescope. We study the diffuse sky emission from ultraviolet to optical wavelengths, which is composed of zodiacal light (ZL), diffuse Galactic light (DGL), and residual emission. The observations were performed towards 54 fields distributed widely over the sky, with spectral coverage from 0.2 to 0.7 μm. In order to avoid contaminating light from earthshine, we use the data collected only in orbital nighttime. The observed intensity is decomposed into the ZL, DGL, and residual emission, in eight photometric bands spanning our spectral coverage. We found that the derived ZL reflectance spectrum is flat in the optical, which indicates major contribution of C-type asteroids to the interplanetary dust (IPD). In addition, the ZL reflectance spectrum has an absorption feature at ∼0.3 μm. The shape of the DGL spectrum is consistent with those found in earlier measurements and model predictions. While the residual emission contains a contribution from the extragalactic background light, we found that the spectral shape of the residual looks similar to the ZL spectrum. Moreover, its optical intensity is much higher than that measured from beyond the IPD cloud by Pioneer 10/11, and also than that of the integrated galaxy light. These findings may indicate the presence of an isotropic ZL component, which is missed in the conventional ZL models.

  6. Herschel discovery of a new class of cold, faint debris discs

    NASA Astrophysics Data System (ADS)

    Eiroa, C.; Marshall, J. P.; Mora, A.; Krivov, A. V.; Montesinos, B.; Absil, O.; Ardila, D.; Arévalo, M.; Augereau, J.-Ch.; Bayo, A.; Danchi, W.; Del Burgo, C.; Ertel, S.; Fridlund, M.; González-García, 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.; Thébault, P.; White, G. J.; Wolf, S.

    2011-12-01

    We present Herschel PACS 100 and 160 μm observations of the solar-type stars α 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 μm for all three stars. HD 210277 also shows a small excess at 100 μm, while the 100 μm fluxes of α Men and HD 88230 agree with the stellar photospheric predictions. We attribute these infrared excesses to a new class of cold, faint debris discs. Both α Men and HD 88230 are spatially resolved in the PACS 160 μm images, while HD 210277 is point-like at that wavelength. The projected linear sizes of the extended emission lie in the range from ~115 to ≤ 250 AU. The estimated black body temperatures from the 100 and 160 μm fluxes are ≲22 K, and the fractional luminosity of the cold dust is Ldust/L ⋆ ~ 10-6, 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, so they cannot be explained easily invoking "classical" debris disc models. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  7. 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.

  8. faint sausage encodes a novel extracellular protein of the immunoglobulin superfamily required for cell migration and the establishment of normal axonal pathways in the Drosophila nervous system.

    PubMed

    Lekven, A C; Tepass, U; Keshmeshian, M; Hartenstein, V

    1998-07-01

    We examined the structure of the nervous system in Drosophila embryos homozygous for a null mutation in the faint sausage (fas) gene. In the peripheral nervous system (PNS) of fas mutants, neurons fail to delaminate from the ectodermal epithelium; in the central nervous system (CNS), the positions of neuronal cell bodies and glial cells are abnormal and normal axonal pathways do not form. Sequence analysis of fas cDNAs revealed that the fas protein product has characteristics of an extracellular protein and that it is a novel member of the immunoglobulin (Ig) superfamily. In situ hybridization demonstrated that fas transcripts are expressed throughout the embryo but they are in relatively high concentrations in the lateral ectoderm, from which the peripheral nervous system delaminates and in the CNS. Antiserum directed against Fas protein was found to stain neurons but not glia in the CNS. We conclude that fas encodes a protein that, in the developing nervous system, is present on the surface of neurons and is essential for nerve cell migration and the establishment of axonal pathways.

  9. High Red Blood Cell Count

    MedlinePlus

    Symptoms High red blood cell count By Mayo Clinic Staff A high red blood cell count is an increase in oxygen-carrying cells in your bloodstream. Red blood cells transport oxygen from your lungs to tissues throughout ...

  10. Mass and environment as drivers of galaxy evolution. III. The constancy of the faint-end slope and the merging of galaxies

    SciTech Connect

    Peng, Ying-jie; Lilly, Simon J.; Carollo, Marcella; Renzini, Alvio

    2014-08-01

    Using our continuity approach, we explore the underlying connections between the evolution of the faint-end slope α{sub s} of the stellar mass function of star-forming galaxies, the logarithmic slope β of the specific star formation rate (sSFR)-mass relation, and the merging of galaxies. We derive analytically the consequences of the observed constancy of α{sub s} since redshifts of at least z ∼ 2. If the logarithmic slope β of the sSFR-mass relation is negative, then the faint-end slope α{sub s} should quickly diverge due to the differential mass increase of galaxies on the star-forming main sequence, and this will also quickly destroy the Schechter form of the mass function. This problem can be solved by removing low-mass galaxies by merging them into more massive galaxies. We quantify this process by introducing the specific merger mass rate (sMMR) as the specific rate of mass added to a given galaxy through mergers. For a modest negative value of β ∼ –0.1, an average sMMR ∼ 0.1 sSFR across the population is required to keep α{sub s} constant with epoch, as observed. This in turn implies a merger rate of ∼0.2 sSFR for major mergers, which is consistent with the available observational estimates. More negative values of β require higher sMMR and higher merger rates, and the steepening of the mass function becomes impossible to control for β < –(α{sub s} + 2). The close link that is required between the in situ sSFR and the sMMR probably arises because both are closely linked to the buildup of dark matter halos. These new findings further develop the formalism for the evolving galaxy population that we introduced earlier and show how striking symmetries in the galaxy population can emerge as the result of deep links between the physical processes involved.

  11. Far-ultraviolet spectroscopy of the quasar UM 675 with the faint object spectrograph on the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Beaver, E. A.; Burbidge, E. M.; Cohen, Ross D.; Junkkarinen, Vesa T.; Lyons, Ronald W.

    1991-01-01

    To investigate the far-UV spectral properties of a QSO and to look for evidence of He I 584 A emission and absorption the Faint Object Spectrograph aboard the HST was used to observed UM 675. Light is detected down to 520 A in the object in the rest frame and limits are set to He I emission, the He I Gunn-Peterson effect at z = 2.148, and Ly-alpha absorption at z roughly 0.5.

  12. 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.

  13. 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.

  14. The Galaxy End Sequence

    NASA Astrophysics Data System (ADS)

    Eales, Stephen; de Vis, Pieter; Smith, Matthew W. L.; Appah, Kiran; Ciesla, Laure; Duffield, Chris; Schofield, Simon

    2017-03-01

    A common assumption is that galaxies fall in two distinct regions of a plot of specific star formation rate (SSFR) versus galaxy stellar mass: a star-forming galaxy main sequence (GMS) and a separate region of 'passive' or 'red and dead galaxies'. Starting from a volume-limited sample of nearby galaxies designed to contain most of the stellar mass in this volume, and thus representing the end-point of ≃12 billion years of galaxy evolution, we investigate the distribution of galaxies in this diagram today. We show that galaxies follow a strongly curved extended GMS with a steep negative slope at high galaxy stellar masses. There is a gradual change in the morphologies of the galaxies along this distribution, but there is no clear break between early-type and late-type galaxies. Examining the other evidence that there are two distinct populations, we argue that the 'red sequence' is the result of the colours of galaxies changing very little below a critical value of the SSFR, rather than implying a distinct population of galaxies. Herschel observations, which show at least half of early-type galaxies contain a cool interstellar medium, also imply continuity between early-type and late-type galaxies. This picture of a unitary population of galaxies requires more gradual evolutionary processes than the rapid quenching process needed to explain two distinct populations. We challenge theorists to predict quantitatively the properties of this 'Galaxy End Sequence'.

  15. 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 ...

  16. Red Hill Updates

    EPA Pesticide Factsheets

    This and other periodic updates are intended to keep the public informed on major progress being made to protect public health and the environment at the Red Hill Underground Fuel Storage Facility in Hawaii.

  17. Faint electric dynamic forces in atmosphere is a possible precursor for a Seismic events phenomena

    NASA Astrophysics Data System (ADS)

    Grigoropoulos, K. N.; Nastos, P. T.; Tselentis, G.; Saragas, E.; Ifantis, A.

    2009-04-01

    The objective of this paper is to monitor the propagation of faint electric forces (D.C. potentials) in Athens' atmosphere before an earthquake. Many authors refer to radio emissions (ELF,HF,VLF,UHF ) before an event. Several other researches have been done with ICE (Instrument Champ Electrique), measurement of quasi-continuous electric fields and electric components of waves, from DC up to 3.5 MHz, or IMSC (Measuring the magnetic components of waves), for measuring magnetic field from a few Hz up to 18 kHz. More studies, within the last twenty years are correlated also with monitoring underground electromagnetic fields from different countries, but few are dealing with D.C.field. The concept is that, the aerosols are injected into the lower atmosphere due to intensifying soil gas content during the increase of seismic activity. At our station in Athens, a continuous monitoring has been conducted by three D.C.detectors which follow the ionosphere variations of the electric field daily, for the years 2007-2008. Multiple antennas have been posted and tested up to the height of thirty meters above the ground. The faint electro potentials received, had been continuously registered by two electrometers. A cross over study of aerosols simulation has been simultaneously done with photo detectors. For this purpose an array of four photo diodes, posted in infrared and visible band in function, and was connected to electro meters too. Several approaches have been taken in past years by researchers attempting to correlate changes in geophysical parameters with earthquake phenomena. In particular, many works examine possible connections of Geoelectric Field (Long and Sort Term Geoelectric Potential) variations to seismic activity and their possible use as precursors of seismic events. Long Term Geoelectric Potential (LTGP) acquisition data consists of potential difference measured between pairs of electrodes placed in the ground at specific location and distance. The electric

  18. 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.

  19. Kernel-Phase Interferometry for Super-Resolution Detection of Faint Companions

    NASA Astrophysics Data System (ADS)

    Factor, Samuel M.; Kraus, Adam L.

    2017-01-01

    Direct detection of close in companions (exoplanets or binary systems) is notoriously difficult. While coronagraphs and point spread function (PSF) subtraction can be used to reduce contrast and dig out signals of companions under the PSF, there are still significant limitations in separation and contrast. Non-redundant aperture masking (NRM) interferometry can be used to detect companions well inside the PSF of a diffraction limited image, though the mask discards ˜95% of the light gathered by the telescope and thus the technique is severely flux limited. Kernel-phase analysis applies interferometric techniques similar to NRM to a diffraction limited image utilizing the full aperture. Instead of non-redundant closure-phases, kernel-phases are constructed from a grid of points on the full aperture, simulating a redundant interferometer. I have developed my own faint companion detection pipeline which utilizes an Bayesian analysis of kernel-phases. I have used this pipeline to search for new companions in archival images from HST/NICMOS in order to constrain planet and binary formation models at separations inaccessible to previous techniques. Using this method, it is possible to detect a companion well within the classical λ/D Rayleigh diffraction limit using a fraction of the telescope time as NRM. This technique can easily be applied to archival data as no mask is needed and will thus make the detection of close in companions cheap and simple as no additional observations are needed. Since the James Webb Space Telescope (JWST) will be able to perform NRM observations, further development and characterization of kernel-phase analysis will allow efficient use of highly competitive JWST telescope time.

  20. 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.

  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. Investigating the Faint young Sun problem with a general circulation model

    NASA Astrophysics Data System (ADS)

    Kunze, M.; Godolt, M.; Langematz, U.; Rauer, H.

    2012-04-01

    The faint young sun problem, the contradiction of a reduced solar luminosity by 15-25% during the Archean and the geologic evidence for relatively high surface temperatures that allowed the presence of liquid water, is still unresolved. It is suggested that the cooling induced by a fainter sun was e.g. offset by higher levels of greenhouse gases (GHGs) during the Archean, but the amounts of GHGs that are necessary to solve the problem can not be supported by proxy data. We present a study in which we investigate this problem by using the Chemistry Climate model EMAC (ECHAM/MESSy Atmospheric Chemistry) with a, spectrally resolved irradiance dataset valid for the Archean. As proxy for the irradiance of the young Sun at 2.5 Ga before today we use the G0V-dwarf star beta Com, which is scaled to have a total solar irradiance of 82% the present value. The EMAC model is used in a configuration with the highly resolving short-wave radiative transfer parametrization FUBRad, coupled to a mixed layer ocean, where the sea surface temperatures and the sea ice are derived from the thermodynamics of an ocean layer. We analyse the climatic impact of the spectrally resolved irradiances and other parameters representing the late Archean Earth, such as the composition of the atmosphere and the land/ocean distribution. We can show that an increase of the CO2 concentration by a factor of 10 is sufficient to obtain liquid oceans in the tropics. Further analysis concentrates on the thermal and dynamical state of the atmosphere with emphasis on the middle atmosphere.

  3. Exploding Satellites—The Tidal Debris of the Ultra-faint Dwarf Galaxy Hercules

    NASA Astrophysics Data System (ADS)

    Küpper, Andreas H. W.; Johnston, Kathryn V.; Mieske, Steffen; Collins, Michelle L. M.; Tollerud, Erik J.

    2017-01-01

    The ultra-faint satellite galaxy Hercules has a strongly elongated and irregular morphology with detections of tidal features up to 1.3 deg (3 kpc) from its center. This suggests that Hercules may be dissolving under the Milky Way’s gravitational influence, and hence could be a tidal stream in formation rather than a bound, dark-matter-dominated satellite. Using Bayesian inference in combination with N-body simulations, we show that Hercules has to be on a very eccentric orbit (ε ≈ 0.95) within the Milky Way in this scenario. On such an orbit, Hercules “explodes” as a consequence of the last tidal shock at pericenter 0.5 Gyr ago. It is currently decelerating toward the apocenter of its orbit with a velocity of V = 157 km s‑1—of which 99% is directed radially outwards. Due to differential orbital plane precession caused by the non-spherical nature of the Galactic potential, its debris fans out nearly perpendicular to its orbit. This explains why Hercules has an elongated shape without showing a distance gradient along its main body: it is in fact a stream that is significantly broader than it is long. In other words, it is moving perpendicular to its apparent major axis. In this scenario, there is a spike in the radial velocity profile created by the dominant debris component that formed through the last pericenter passage. This is similar to kinematic substructure that is observed in the real Hercules. Modeling a satellite on such a highly eccentric orbit is strongly dependent on the form of the Galactic potential. We therefore propose that detailed kinematic investigation of Hercules and other exploding satellite candidates can yield strong constraints on the potential of the Milky Way.

  4. A DEEPER LOOK AT FAINT Hα EMISSION IN NEARBY DWARF GALAXIES

    SciTech Connect

    Lee, Janice C.; Hilbert, Bryan; Veilleux, Sylvain; McDonald, Michael

    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{sup −18} erg s{sup −1} cm{sup −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.

  5. 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 ☉}.

  6. Faint Population III Supernovae as the Origin of the Most Iron-poor Stars

    NASA Astrophysics Data System (ADS)

    Ishigaki, Miho N.; Tominaga, Nozomu; Kobayashi, Chiaki; Nomoto, Ken'ichi

    2014-09-01

    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 51 = E/1051 erg =1) and hypernovae (E 51 >= 10) of Population III 25 M ⊙ or 40 M ⊙ 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 56Ni less than 10-3 M ⊙.

  7. Faint gamma-ray bursts and other high-energy transients detected with BATSE

    NASA Astrophysics Data System (ADS)

    Kommers, Jefferson Michael

    1999-03-01

    The Burst and Transient Source Experiment (BATSE) onboard the Compton Gamma Ray Observatory detects gamma-ray bursts (GRBs) and other high-energy astronomical transients using a real-time burst detection system running onboard the spacecraft. This thesis describes a search of the archival BATSE data for GRBs, emission from soft gamma-ray repeaters (SGRs), bursts and flares from X-ray binaries, and other transients that were not detected by the onboard system. The search covers six years of the mission, from 1992 December 9.0 to 1997 December 17.0. The search reveals 873 GRB candidates that did not activate the onboard burst detection because they were too faint, because they occurred while the onboard system was disabled for technical reasons, or because their time profile artificially raised the onboard detection threshold. The catalog of these bursts increases the number of GRBs detected with BATSE by 48% during the time period of the search. The intensity distribution of the GRBs detected with the search reaches peak fluxes that are a factor of ~2 lower than could be studied previously. The value of the statistic (in Euclidean space) for these bursts, 0.177 +/- 0.006, is the lowest so far obtained for a global sample of GRBs. The differential peak flux distribution is consistent with cosmological models in which the co-moving GRB rate approximately traces the star-formation history of the Universe. These results suggest that more sensitive detectors are likely to discover relatively few GRBs (of the kind currently known) that are fainter than the BATSE detection threshold. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. FAINT HIGH-ENERGY GAMMA-RAY PHOTON EMISSION OF GRB 081006A FROM FERMI OBSERVATIONS

    SciTech Connect

    Zheng Weikang; Akerlof, Carl W.; Pandey, Shashi B.; McKay, Timothy A.; Zhang Binbin; Zhang Bing

    2012-01-20

    Since the launch of the Fermi Gamma-ray Space Telescope on 2008 June 11, the Large Area Telescope (LAT) instrument has firmly detected more than 20 gamma-ray bursts (GRBs) with high-energy photon emission above 100 MeV. Using the matched filter technique, three more GRBs have also shown evidence of correlation with high-energy photon emission as demonstrated by Akerlof et al. In this paper, we present another GRB, GRB 081006A, unambiguously detected by the matched filter technique. This event is associated with more than 13 high-energy photons above 100 MeV. The likelihood analysis code provided by the Fermi Science Support Center generated an independent verification of this detection using a comparison of the test statistics value with similar calculations for random LAT data fields. We have performed detailed temporal and spectral analysis of photons from 8 keV up to 0.8 GeV from the Gamma-ray Burst Monitor and the LAT. The properties of GRB 081006A can be compared to those of the other two long-duration GRBs detected at similar significance, GRB 080825C and GRB 090217A. We find that GRB 081006A is more similar to GRB 080825C with comparable appearances of late high-energy photon emission. As demonstrated previously, there appears to be a surprising dearth of faint LAT GRBs, with only one additional GRB identified in a sample of 74. In this unique period when both Swift and Fermi are operational, there is some urgency to explore this aspect of GRBs as fully as possible.

  13. Aurora Australis, Red Crown

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Aurora Australis or Southern Lights (location unknown) shows a spiked band of red airglow called a 'Red Crown' above the Earth Limb. Calculated to be in the 80 - 120 km altitude region, auroral activity is due to exitation of atomic oxygen in the upper atmosphere by radiation from the van Allen Radiation Belts and is most common above the 65 degree north and south latitude range during the spring and fall of the year.

  14. Egypt and Red Sea

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A panaramic view of eastern Egypt, The Red Sea and Saudi Arabia beyond (24.0N, 33.0E). In this desert country, where water is life, the high Aswan Dam and the impounded waters of the Nile River in the foreground assure water availability into the next century. The Red Sea beyond, part of the Suez Canal seaway, serves as a commercial link to the world and separates Egypt from Saudi Arabia.

  15. 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.

  16. 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.

  17. Massive unseen companions to hot faint underluminous stars from SDSS (MUCHFUSS). Analysis of seven close subdwarf B binaries

    NASA Astrophysics Data System (ADS)

    Geier, S.; Maxted, P. F. L.; Napiwotzki, R.; Østensen, R. H.; Heber, U.; Hirsch, H.; Kupfer, T.; Müller, S.; Tillich, A.; Barlow, B. N.; Oreiro, R.; Ottosen, T. A.; Copperwheat, C.; Gänsicke, B. T.; Marsh, T. R.

    2011-02-01

    The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs (M > 1.0 M⊙), neutron stars or stellar mass black holes. The existence of such systems is predicted by binary evolution theory and recent discoveries indicate that they exist in our Galaxy. First results are presented for seven close binary sdBs with short orbital periods ranging from ≃ 0.21 d to 1.5 d. The atmospheric parameters of all objects are compatible with core helium-burning stars. The companions are most likely white dwarfs. In one case the companion could be shown to be a white dwarf by the absence of light-curve variations. However, in most cases late type main sequence stars cannot be firmly excluded. Comparing our small sample with the known population of close sdB binaries we show that our target selection method aiming at massive companions is efficient. The minimum companion masses of all binaries in our sample are high compared to the reference sample of known sdB binaries. Based on observations at the Paranal Observatory of the European Southern Observatory for programme number 081.D-0819. Based on observations at the La Silla Observatory of the European Southern Observatory for programmes number 082.D-0649 and 084.D-0348. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC). Based on observations with the William Herschel Telescope and the Isaac Newton Telescope operated both by the Isaac Newton Group at the Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias on the island of La Palma, Spain. Based on observations with the Southern Astrophysical Research (SOAR) telescope operated by the U.S. National Optical Astronomy Observatory (NOAO), the Ministerio da Ciłncia e

  18. 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.

  19. The search for faint radio supernova remnants in the outer Galaxy: five new discoveries

    NASA Astrophysics Data System (ADS)

    Gerbrandt, Stephanie; Foster, Tyler J.; Kothes, Roland; Geisbüsch, Jörn; Tung, Albert

    2014-06-01

    Context. High resolution and sensitivity large-scale radio surveys of the Milky Way are critical in the discovery of very low surface brightness supernova remnants (SNRs), which may constitute a significant portion of the Galactic SNRs still unaccounted for (ostensibly the "missing SNR problem"). Aims: The overall purpose here is to present the results of a systematic, deep data-mining of the Canadian Galactic plane Survey (CGPS) for faint, extended non-thermal and polarized emission structures that are likely the shells of uncatalogued SNRs. Methods: We examine 5 × 5 degree mosaics from the entire 1420 MHz continuum and polarization dataset of the CGPS after removing unresolved "point" sources and subsequently smoothing them. Newly revealed extended emission objects are compared to similarly prepared CGPS 408 MHz continuum mosaics, as well as to source-removed mosaics from various existing radio surveys at 4.8 GHz, 2.7 GHz, and 327 MHz, to identify candidates with non-thermal emission characteristics. We integrate flux densities at each frequency to characterise the radio spectra behaviour of these candidates. We further look for mid- and high-frequency (1420 MHz, 4.8 GHz) ordered polarized emission from the limb brightened "shell"-like continuum features that the candidates sport. Finally, we use IR and optical maps to provide additional backing evidence. Results: Here we present evidence that five new objects, identified as filling all or some of the criteria above, are strong candidates for new SNRs. These five are designated by their Galactic coordinate names G108.5+11.0, G128.5+2.6, G149.5+3.2, G150.8+3.8, and G160.1-1.1. The radio spectrum of each is presented, highlighting their steepness, which is characteristic of synchrotron radiation. CGPS 1420 MHz polarization data and 4.8 GHz polarization data also provide evidence that these objects are newly discovered SNRs. These discoveries represent a significant increase in the number of SNRs known in the outer

  20. 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

  1. Stellar kinematics and metallicities in the ultra-faint dwarf galaxy Reticulum II

    DOE PAGES

    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

  2. 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.

  3. 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

    2014-04-07

    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. 

  4. 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.

  5. Exploring the faint young Sun problem and the possible climates of the Archean Earth with a 3-D GCM

    NASA Astrophysics Data System (ADS)

    Charnay, B.; Forget, F.; Wordsworth, R.; Leconte, J.; Millour, E.; Codron, F.; Spiga, A.

    2013-09-01

    Different solutions have been proposed to solve the "faint young Sun problem," defined by the fact that the Earth was not fully frozen during the Archean despite the fainter Sun. Most previous studies were performed with simple 1-D radiative convective models and did not account well for the clouds and ice-albedo feedback or the atmospheric and oceanic transport of energy. We apply a global climate model (GCM) to test the different solutions to the faint young Sun problem. We explore the effect of greenhouse gases (CO2 and CH4), atmospheric pressure, cloud droplet size, land distribution, and Earth's rotation rate. We show that neglecting organic haze, 100 mbar of CO2 with 2 mbar of CH4 at 3.8 Ga and 10 mbar of CO2 with 2 mbar of CH4 at 2.5 Ga allow a temperate climate (mean surface temperature between 10°C and 20°C). Such amounts of greenhouse gases remain consistent with the geological data. Removing continents produces a warming lower than +4°C. The effect of rotation rate is even more limited. Larger droplets (radii of 17 μm versus 12 μm) and a doubling of the atmospheric pressure produce a similar warming of around +7°C. In our model, ice-free water belts can be maintained up to 25°N/S with less than 1 mbar of CO2 and no methane. An interesting cloud feedback appears above cold oceans, stopping the glaciation. Such a resistance against full glaciation tends to strongly mitigate the faint young Sun problem.

  6. 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).

  7. 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.

  8. Sequencing technologies and genome sequencing.

    PubMed

    Pareek, Chandra Shekhar; Smoczynski, Rafal; Tretyn, Andrzej

    2011-11-01

    The high-throughput - next generation sequencing (HT-NGS) technologies are currently the hottest topic in the field of human and animals genomics researches, which can produce over 100 times more data compared to the most sophisticated capillary sequencers based on the Sanger method. With the ongoing developments of high throughput sequencing machines and advancement of modern bioinformatics tools at unprecedented pace, the target goal of sequencing individual genomes of living organism at a cost of $1,000 each is seemed to be realistically feasible in the near future. In the relatively short time frame since 2005, the HT-NGS technologies are revolutionizing the human and animal genome researches by analysis of chromatin immunoprecipitation coupled to DNA microarray (ChIP-chip) or sequencing (ChIP-seq), RNA sequencing (RNA-seq), whole genome genotyping, genome wide structural variation, de novo assembling and re-assembling of genome, mutation detection and carrier screening, detection of inherited disorders and complex human diseases, DNA library preparation, paired ends and genomic captures, sequencing of mitochondrial genome and personal genomics. In this review, we addressed the important features of HT-NGS like, first generation DNA sequencers, birth of HT-NGS, second generation HT-NGS platforms, third generation HT-NGS platforms: including single molecule Heliscope™, SMRT™ and RNAP sequencers, Nanopore, Archon Genomics X PRIZE foundation, comparison of second and third HT-NGS platforms, applications, advances and future perspectives of sequencing technologies on human and animal genome research.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  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 sea drillings.

    PubMed

    Ross, D A; Whitmarsh, R B; Ali, S A; Boudreaux, J E; Coleman, R; Fleisher, R L; Girdler, R; Manheim, F; Matter, A; Nigrini, C; Stoffers, P; Supko, P R

    1973-01-26

    Recent drilling in the Red Sea has shown that much of the basin is underlain by evaporites of a similar age to that of evaporites found in the Mediterranean Sea. These evaporites and their structural positions indicate that other brine areas are present-and, indeed, several others have been discovered.

  15. 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)

  16. 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.

  17. RED2TEX: A TRIX RED to LATEX converter

    SciTech Connect

    Chase, L.; Langdon, A.B.

    1987-05-20

    A summary of RED2TEX is presented. RED2TEX converts standard TRIX RED format commands to TEX or LATEX commands for subsequent LATEX formatting. LATEX is a special version of the TEX document preparation system. LATEX adds to TEX a collection of commands that simplifies formatting. LATEX runs on the J-Vax and the LLL-LCC Pyramid machines. RED2TEX resides in Unix directory CHASE/TEX.

  18. Faint Intergalactic Redshifted Emission Balloon (FIREBALL)-2: Flight Test of Next Generation UV Detector and Spectrograph (Lead Institution)

    NASA Astrophysics Data System (ADS)

    Martin, Christopher

    We have developed and successfully flown a path-finding experiment, for which this is the lead proposal, the Faint Intergalactic-medium Redshifted Emission Balloon (FIREBALL), designed to discover and map faint emission from the Intergalactic Medium (IGM). Our successful science flight in June 2009, proved every aspect of the complex instrument performance, and provided the strongest measurements and constraints on IGM emission available from any instrument. We are preparing a significantly upgraded experiment, FIREBALL-2, for launch in Fall 2015 at Ft. Sumner, New Mexico. We have made progress in spectrograph, detector, and payload design and development. CNES is providing the spectrograph, gondola, and gondola flight support team. Because of a CNES balloon mishap and funding constraints, support for a FIREBALL launch was delayed from Fall 2013 to Fall 2015. We propose 18 months of bridge funding to support the FIREBALL team that includes two female graduate students and one female Post Doctoral scholar (separately supported by NSF and Caltech Millikan Fellowships). FIREBALL directly supports NASA Science Plan Objectives to "Understand the many phenom-ena and processes associated with galaxy, stellar, and planetary system formation and evolution from the earliest epochs to today." FIREBALL directly addresses four Core Science Questions from the Astrophysics 2010 Decadal Survey (New Worlds New Horizons). FIREBALL provides flight and science testing of new UV technologies directly called out by NWNH as high priority for the next decade as a precursor to a 4-m class UV/optical future mission.

  19. What do you gain from deconvolution? - Observing faint galaxies with the Hubble Space Telescope Wide Field Camera

    NASA Technical Reports Server (NTRS)

    Schade, David J.; Elson, Rebecca A. W.

    1993-01-01

    We describe experiments with deconvolutions of simulations of deep HST Wide Field Camera images containing faint, compact galaxies to determine under what circumstances there is a quantitative advantage to image deconvolution, and explore whether it is (1) helpful for distinguishing between stars and compact galaxies, or between spiral and elliptical galaxies, and whether it (2) improves the accuracy with which characteristic radii and integrated magnitudes may be determined. The Maximum Entropy and Richardson-Lucy deconvolution algorithms give the same results. For medium and low S/N images, deconvolution does not significantly improve our ability to distinguish between faint stars and compact galaxies, nor between spiral and elliptical galaxies. Measurements from both raw and deconvolved images are biased and must be corrected; it is easier to quantify and remove the biases for cases that have not been deconvolved. We find no benefit from deconvolution for measuring luminosity profiles, but these results are limited to low S/N images of very compact (often undersampled) galaxies.

  20. PROBING THE FAINT END OF THE QUASAR LUMINOSITY FUNCTION AT z{approx} 4 IN THE COSMOS FIELD

    SciTech Connect

    Ikeda, H.; Nagao, T.; Matsuoka, K.; Ideue, Y.; Taniguchi, Y.; Shioya, Y.; Trump, J. R.; Comastri, A.; Enoki, M.; Koekemoer, A. M.; Morokuma, T.; Murayama, T.; Saito, T.; Silverman, J. D.; Salvato, M.; Schinnerer, E.

    2011-02-20

    We searched for quasars that are {approx}3 mag fainter than the SDSS quasars in the redshift range 3.7 {approx}< z {approx}< 4.7 in the COSMOS field to constrain the faint end of the quasar luminosity function (QLF). Using optical photometric data, we selected 31 quasar candidates with 22 < i' < 24 at z {approx} 4. We obtained optical spectra for most of these candidates using FOCAS on the Subaru telescope and identified eight low-luminosity quasars at z {approx} 4. In order to derive the QLF based on our spectroscopic follow-up campaign, we estimated the photometric completeness of our quasar survey through detailed Monte Carlo simulations. Our QLF at z {approx} 4 has a much shallower faint-end slope ({beta} = -1.67{sup +0.11}{sub -0.17}) than that obtained by other recent surveys in the same redshift. Our result is consistent with the scenario of downsizing evolution of active galactic nuclei inferred by recent optical and X-ray quasar surveys at lower redshifts.

  1. Faint Intergalactic Redshifted Emission Balloon (FIREBALL)-2: Flight Test of Next Generation UV Detector and Spectrograph (Co-I Proposal)

    NASA Astrophysics Data System (ADS)

    Schiminovich, David

    Columbia University is a Co-I institution in a collaborative research program with Caltech, the Lead Institution (PI: Christopher Martin). We have developed and successfully flown a path-finding experiment, the Faint Intergalactic-medium Redshifted Emission Balloon (FIREBALL), designed to discover and map faint emission from the Intergalactic Medium (IGM). Our successful science flight in June 2009, proved every aspect of the complex instrument performance, and provided the strongest measurements and constraints on IGM emission available from any instrument. We are preparing a significantly upgraded experiment, FIREBALL-2, for launch in Fall 2015 at Ft. Sumner, New Mexico. We have made progress in spectrograph, detector, and payload design and development. CNES is providing the spectrograph, gondola, and gondola flight support team. Because of a CNES balloon mishap and funding constraints, support for a FIREBALL launch was delayed from Fall 2013 to Fall 2015. We propose 18 months of bridge funding to support the FIREBALL team that includes one woman Ph.D. student at Columbia University. FIREBALL directly supports NASA Science Plan Objectives to "Understand the many phenomena and processes associated with galaxy, stellar, and planetary system formation and evolution from the earliest epochs to today." FIREBALL directly addresses four Core Science Questions from the Astrophysics 2010 Decadal Survey (New Worlds New Horizons). FIREBALL provides flight and science testing of new UV technologies directly called out by NWNH as high priority for the next decade as a precursor to a 4-m class UV/optical future mission.

  2. The faint end slope of the UV LF at z~2 from the Hubble UV Ultra Deep Field

    NASA Astrophysics Data System (ADS)

    Mehta, Vihang; Scarlata, Claudia; Rafelski, Marc; Gburek, Timothy; Teplitz, Harry I.; Alavi, Anahita; Siana, Brian D.; Finkelstein, Steven L.

    2016-01-01

    We present the z˜2 UV luminosity function (LF) at 1500Å derived using UV imaging data obtained as part of the Hubble Ultra-Violet Ultra Deep Field (UVUDF) program (Teplitz et al. 2013). We apply the Lyman break dropout selection to isolate a sample of z˜2 Lyman-break galaxy (LBG) candidates. We perform simulations to quantify the survey incompleteness for UVUDF, as a function of magnitude and size, and also compute the selection function for our dropout selection criteria. Our simulations indicate that we are 50% complete at M1500=-17.5 (AB). We used the modified maximum likelihood estimator introduced in Mehta et al. (2015) to derive the best fit parameters of the Schechter luminosity function. The faint end slope value for the z˜2 UV LF in recent literature ranges from very steep (α=-1.74) to considerably shallow (α=-1.17) values. We find a faint end slope value that lies in between these extremes.

  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. 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.

  5. 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.

  6. Stellar Parameters and Winds of Red Supergiants in Binaries

    NASA Astrophysics Data System (ADS)

    Bennett, K.

    The proposed target stars (zeta Aur, 31 Cyg) are eclipsing binary systems with K supergiant primaries and B-type main sequence companions. From these binaries, we will determine key information about fundamental stellar parameters and outer atmospheric structure that can not be obtained from observations of single red supergiants. The proposed observations are directed towards understanding the mass loss process driving the massive winds of red supergiants. In particular, the proposed FUSE observations will support the following analyses: -- detailed model atmosphere analyses of the B-stars' continua -- determining accurate radial velocities of the B-type secondaries -- analyses of the wind absorption features of the red supergiant primaries. From these FUSE observations, we will determine improved fundamental stellar parameters of red supergiants (effective temperatures, radii, masses and luminosities) and wind properties (velocity laws and mass loss rates).

  7. The Mass and Age Dependence of Dusty Red Supergiant Winds, and Their Impact on Supernova Progenitors

    NASA Astrophysics Data System (ADS)

    Smith, Nathan

    The dusty winds of red supergiants (RSGs) have a tremendous impact on the evolution of stars of 8-40 M_sun. Wind strength determines whether a star can shed its H envelope or not, thus determining the type of resulting SN, and these dusty winds create the circumstellar medium (CSM) at the end of the stars life. However, RSG mass-loss rates are very uncertain, which hampers the predictive power of stellar evolution models. RSGs are expected to end their lives as Type II-P supernovae. Many RSGs are observed with initial masses well above 20 M_sun, but from Type II-P progenitors directly detected so far it seems that the stars that explode are of relatively low mass, with all progenitor mass estimates below 16-17 M_sun. This is known as the Red Supergiant Problem, prompting suggestions that the massive RSGs collapse to black holes with undetectably faint SNe. Alternatively, it has also been suggested that the more massive RSGs evolve to yield other types of SNe or that dusty CSM could cause the progenitor to faint, underestimating its mass. One expects that the most massive and most evolved RSGs would also have the highest extinction or would be the most likely to evolve to a H-free star -- this is qualitatively what is needed to explain the missing high-mass RSGs. To test this idea, we propose to use FORCAST to obtain mid-IR photometry for RSGs in three coeval star clusters with known ages(and different turnoff masses of 12, 18, and 35 M_sun). By modeling CSM dust emission, we will derive mass and age dependent mass-loss rates and CSM extinction, below and above the derived cutoff mass for Type II-P progenitors, thereby determining whether this effect is large enough to solve the Red Supergiant Problem.

  8. Faint Submillimeter Galaxies Identified through Their Optical/Near-infrared Colors. I. Spatial Clustering and Halo Masses

    NASA Astrophysics Data System (ADS)

    Chen, Chian-Chou; Smail, Ian; Swinbank, A. M.; Simpson, James M.; Almaini, Omar; Conselice, Christopher J.; Hartley, Will G.; Mortlock, Alice; Simpson, Chris; Wilkinson, Aaron

    2016-11-01

    The properties of submillimeter galaxies (SMGs) that are fainter than the confusion limit of blank-field single-dish surveys ({S}850 ≲ 2 mJy) are poorly constrained. Using a newly developed color selection technique, Optical-Infrared Triple Color (OIRTC), that has been shown to successfully select such faint SMGs, we identify a sample of 2938 OIRTC-selected galaxies, dubbed Triple Color Galaxies (TCGs), in the UKIDSS-UDS field. We show that these galaxies have a median 850 μm flux of {S}850=0.96+/- 0.04 mJy (equivalent to a star formation rate SFR ˜ 60{--}100 {M}⊙ yr-1 based on spectral energy distribution fitting), representing the first large sample of faint SMGs that bridges the gap between bright SMGs and normal star-forming galaxies in S 850 and L IR. We assess the basic properties of TCGs and their relationship with other galaxy populations at z˜ 2. We measure the two-point autocorrelation function for this population and derive a typical halo mass of log10({M}{halo}) = {12.9}-0.3+0.2, {12.7}-0.2+0.1, and {12.9}-0.3+0.2 {h}-1 {M}⊙ at z=1{--}2, 2-3, and 3-5, respectively. Together with the bright SMGs ({S}850≳ 2 mJy) and a comparison sample of less far-infrared luminous star-forming galaxies, we find a lack of dependence between spatial clustering and S 850 (or SFR), suggesting that the difference between these populations may lie in their local galactic environment. Lastly, on the scale of ˜ 8{--}17 {kpc} at 1\\lt z\\lt 5 we find a tentative enhancement of the clustering of TCGs over the comparison star-forming galaxies, suggesting that some faint SMGs are physically associated pairs, perhaps reflecting a merging origin in their triggering.

  9. Sweating the small stuff: simulating dwarf galaxies, ultra-faint dwarf galaxies, and their own tiny satellites

    NASA Astrophysics Data System (ADS)

    Wheeler, Coral Rose

    2016-06-01

    The high dark matter content and the shallow potential wells of low mass galaxies (10^3 Msun < Mstar < 10^9.5 Msun) make them excellent testbeds for differing theories of galaxy formation. Additionally, the recent up-tick in the number and detail of Local Group dwarf galaxy observations provides a rich dataset for comparison to simulations that attempt to answer important questions in near field cosmology: why are there so few observed dwarfs compared to the number predicted by simulations? What shuts down star formation in ultra-faint galaxies? Why do dwarfs have inverted age gradients and what does it take to convert a dwarf irregular (dIrrs) into a dwarf spheroidal (dSph) galaxy?We to attempt to answer these questions by running ultra-high resolution cosmological FIRE simulations of isolated dwarf galaxies. We predict that many ultra-faint dwarfs should exist as satellites of more massive isolated Local Group dwarfs. The ultra-faints (Mstar < 10^4 Msun) formed in these simulations have uniformly ancient stellar populations (> 10 Gyr), having had their star formation shut down by reionization. Additionally, we show that the kinematics and ellipticities of isolated simulated dwarf centrals are consistent with observed dSphs satellites without the need for harassment from a massive host. We further show that most (but not all) observed *isolated* dIrrs in the Local Volume also have dispersion-supported stellar populations, contradicting the previous view that these objects are rotating. Finally, we investigate the stellar age gradients in dwarfs — showing that early mergers and strong feedback can create an inverted gradient, with the older stars occupying larger galactocentric radii.These results offer an interesting direction in testing models that attempt to solve dark matter problems via explosive feedback episodes. Can the same models that create large cores in simulated dwarfs preserve the mild stellar rotation that is seen in a minority of isolated d

  10. 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.

  11. Depositional environments of the Red Fork Sandstone in Custer and Roger Mills Counties, southwestern Oklahoma

    SciTech Connect

    Tolson, P.M. )

    1993-09-01

    The Desmoinesian Red Fork formation is a prolific, overpressured gas-producing sequence of interbedded sandstones and shales. Total thickness ranges from less than 100 ft (northeast) to more than 1100 ft (south). Isopach maps suggest that syndepositional faulting controlled major depositional trends. The lower Red Fork, whose base is defined by a persistent, hot, black shale (sequence boundary ), is mainly deep-marine shale and siltstone. Two major shallowing-upward deltaic sequences separated by a marine transgression are evident in the middle (50-400-ft thick) and upper (30-250-ft thick) Red Fork. The middle Red Fork is marine dominated and was deposited into a relatively deep basin on a steep, unstable delta-front slope. In contrast, the upper Red Fork deltaic sequence is more fluvial dominated and was deposited in shallower water. The upper Red Fork is overlain by the Pink lime interval which appears to be shallow-marine/lagoonal black shale. The Pink lime contains fish scales, coffee-ground to branch-size lignitic plant debris, and brackish to shallow-marine ostracodes, linguloid brachiopods, Tasmanites algae, and gastropods. Most of the Red Fork has an easterly, possibly Ouachita Mountain area source. The prolific Southwest Leedey field has a different mineral assemblage and diagenetic sequence and may have a northern source.

  12. Mass influx obtained from low-light-level television observations of faint meteors. [for modeling meteoroid mass distribution

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    Low light level television systems 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 gram. The results of these observations, using image orthicons and intensified vidicons, 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 meteor 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.

  13. Investigation of Variability of Faint Galactic Early-Type Carbon Stars from the First Byurakan Spectral Sky Survey

    NASA Astrophysics Data System (ADS)

    Gigoyan, K. S.; Kostandyan, G. R.; Paronyan, G. M.

    2016-06-01

    In this poster, we discuss the nature of 66 faint carbon (C) stars which have been discovered by scrutinizing the plates of the First Byurakan Survey (FBS). These plates display low-resolution spectra of objects located at high Galactic latitudes and have a limiting magnitude of about V=16. Our sample of 66 confirmed spectroscopically to be C stars. These 66 objects are those which show early-type spectra. To better characterize these objects, medium-resolution CCD spectra were obtained and are exploited for them all, together with consideration of their 2MASS near-infrared (NIR) colors and their optical variability. We derive effective temperatures from photometry. Finally, the optical variability of our objects are studied by using the data of the Catalina Sky Survey (CSS). It is found that the vast majority does not display variability. However, for some of them, the phased light curve may indicate the presence of a secondary component.

  14. BEASTS OF THE SOUTHERN WILD: DISCOVERY OF NINE ULTRA FAINT SATELLITES IN THE VICINITY OF THE MAGELLANIC CLOUDS

    SciTech Connect

    Koposov, Sergey E.; Belokurov, Vasily; Torrealba, Gabriel; Evans, N. Wyn E-mail: vasily@ast.cam.ac.uk

    2015-06-01

    We have used the publicly released Dark Energy Survey (DES) data to hunt for new satellites of the Milky Way (MW) in the southern hemisphere. Our search yielded a large number of promising candidates. In this paper, we announce the discovery of nine new unambiguous ultra-faint objects, whose authenticity can be established with the DES data alone. Based on the morphological properties, three of the new satellites are dwarf galaxies, one of which is located at the very outskirts of the MW, at a distance of 380 kpc. The remaining six objects have sizes and luminosities comparable to the Segue 1 satellite and cannot be classified straightforwardly without follow-up spectroscopic observations. The satellites we have discovered cluster around the LMC and the SMC. We show that such spatial distribution is unlikely under the assumption of isotropy, and, therefore, conclude that at least some of the new satellites must have been associated with the Magellanic Clouds in the past.

  15. Improved γ/hadron separation for the detection of faint γ-ray sources using boosted decision trees

    NASA Astrophysics Data System (ADS)

    Krause, Maria; Pueschel, Elisa; Maier, Gernot

    2017-03-01

    Imaging atmospheric Cherenkov telescopes record an enormous number of cosmic-ray background events. Suppressing these background events while retaining γ-rays is key to achieving good sensitivity to faint γ-ray sources. The differentiation between signal and background events can be accomplished using machine learning algorithms, which are already used in various fields of physics. Multivariate analyses combine several variables into a single variable that indicates the degree to which an event is γ-ray-like or cosmic-ray-like. In this paper we will focus on the use of "boosted decision trees" for γ/hadron separation. We apply the method to data from the Very Energetic Radiation Imaging Telescope Array System (VERITAS), and demonstrate an improved sensitivity compared to the VERITAS standard analysis.

  16. CONSTRAINTS ON THE FAINT END OF THE QUASAR LUMINOSITY FUNCTION AT z {approx} 5 IN THE COSMOS FIELD

    SciTech Connect

    Ikeda, H.; Matsuoka, K.; Kajisawa, M.; Nagao, T.; Taniguchi, Y.; Shioya, Y.; Enoki, M.; Capak, P.; Masters, D.; Scoville, N. Z.; Civano, F.; Koekemoer, A. M.; Morokuma, T.; Salvato, M.; Schinnerer, E.

    2012-09-10

    We present the result of our low-luminosity quasar survey in the redshift range of 4.5 {approx}< z {approx}< 5.5 in the COSMOS field. Using the COSMOS photometric catalog, we selected 15 quasar candidates with 22 < i' < 24 at z {approx} 5 that are {approx}3 mag fainter than the Sloan Digital Sky Survey quasars in the same redshift range. We obtained optical spectra for 14 of the 15 candidates using FOCAS on the Subaru Telescope and did not identify any low-luminosity type-1 quasars at z {approx} 5, while a low-luminosity type-2 quasar at z {approx} 5.07 was discovered. In order to constrain the faint end of the quasar luminosity function at z {approx} 5, we calculated the 1{sigma} confidence upper limits of the space density of type-1 quasars. As a result, the 1{sigma} confidence upper limits on the quasar space density are {Phi} < 1.33 Multiplication-Sign 10{sup -7} Mpc{sup -3} mag{sup -1} for -24.52 < M{sub 1450} < -23.52 and {Phi} < 2.88 Multiplication-Sign 10{sup -7} Mpc{sup -3} mag{sup -1} for -23.52 < M{sub 1450} < -22.52. The inferred 1{sigma} confidence upper limits of the space density are then used to provide constraints on the faint-end slope and the break absolute magnitude of the quasar luminosity function at z {approx} 5. We find that the quasar space density decreases gradually as a function of redshift at low luminosity (M{sub 1450} {approx} -23), being similar to the trend found for quasars with high luminosity (M{sub 1450} < -26). This result is consistent with the so-called downsizing evolution of quasars seen at lower redshifts.

  17. MOA-2008-BLG-379Lb: A massive planet from a high magnification event with a faint source

    SciTech Connect

    Suzuki, D.; Sumi, T.; Fukagawa, M.; Shibai, H.; Udalski, A.; Bennett, D. P.; Bond, I. A.; Ling, C. H.; Abe, F.; Furusawa, K.; Itow, Y.; Masuda, K.; Matsubara, Y.; Botzler, C. S.; Freeman, M.; Rattenbury, N.; Fukui, A.; Muraki, Y.; Ohnishi, K.; Saito, To.; Collaboration: MOA Collaboration; OGLE Collaboration; and others

    2014-01-10

    We report on the analysis of the high microlensing event MOA-2008-BLG-379, which has a strong microlensing anomaly at its peak due to a massive planet with a mass ratio of q = 6.9 × 10{sup –3}. Because the faint source star crosses the large resonant caustic, the planetary signal dominates the light curve. This is unusual for planetary microlensing events, and as a result, the planetary nature of this light curve was not immediately noticed. The planetary nature of the event was found when the Microlensing Observations in Astrophysics (MOA) Collaboration conducted a systematic study of binary microlensing events previously identified by the MOA alert system. We have conducted a Bayesian analysis based on a standard Galactic model to estimate the physical parameters of the lens system. This yields a host star mass of M{sub L}=3.3{sub −1.2}{sup +1.7} M{sub ⊙} orbited by a planet of mass m{sub P}=0.56{sub −0.27}{sup +0.24} M{sub Jup} at an orbital separation of a=3.3{sub −1.2}{sup +1.3} AU at a distance of D{sub L}=4.1{sub −1.9}{sup +1.7} kpc. The faint source magnitude of I {sub S} = 21.30 and relatively high lens-source relative proper motion of μ{sub rel} = 7.6 ± 1.6 mas yr{sup –1} imply that high angular resolution adaptive optics or Hubble Space Telescope observations are likely to be able to detect the source star, which would determine the masses and distance of the planet and its host star.

  18. Fundamental Physics with the Hubble Frontier Fields: Constraining Dark Matter Models with the Abundance of Extremely Faint and Distant Galaxies

    NASA Astrophysics Data System (ADS)

    Menci, N.; Merle, A.; Totzauer, M.; Schneider, A.; Grazian, A.; Castellano, M.; Sanchez, N. G.

    2017-02-01

    We show that the measured abundance of ultra-faint lensed galaxies at z≈ 6 in the Hubble Frontier Fields (HFF) provides stringent constraints on the parameter space of (i) dark matter models based on keV sterile neutrinos; (ii) “fuzzy” wavelike dark matter models, based on Bose–Einstein condensates of ultra-light particles. For the case of sterile neutrinos, we consider two production mechanisms: resonant production through mixing with active neutrinos and the decay of scalar particles. For the former model, we derive constraints for the combination of sterile neutrino mass {m}ν and mixi