Science.gov

Sample records for deep survey evolution

  1. A very deep IRAS survey - Constraints on the evolution of starburst galaxies

    NASA Astrophysics Data System (ADS)

    Hacking, Perry; Condon, J. J.; Houck, J. R.

    1987-05-01

    Counts of sources (primarily starburst galaxies) from a deep 60 microns IRAS survey published by Hacking and Houck (1987) are compared with four evolutionary models. The counts below 100 mJy are higher than expected if no evolution has taken place out to a redshift of approximately 0.2. Redshift measurements of the survey sources should be able to distinguish between luminosity-evolution and density-evolution models and detect as little as a 20 percent brightening or increase in density of infrared sources per billion years ago (H/0/ = 100 km/s per Mpc). Starburst galaxies cannot account for the reported 100 microns background without extreme evolution at high redshifts.

  2. Very deep IRAS survey - constraints on the evolution of starburst galaxies

    SciTech Connect

    Hacking, P.; Houck, J.R.; Condon, J.J.

    1987-05-01

    Counts of sources (primarily starburst galaxies) from a deep 60 microns IRAS survey published by Hacking and Houck (1987) are compared with four evolutionary models. The counts below 100 mJy are higher than expected if no evolution has taken place out to a redshift of approximately 0.2. Redshift measurements of the survey sources should be able to distinguish between luminosity-evolution and density-evolution models and detect as little as a 20 percent brightening or increase in density of infrared sources per billion years ago (H/0/ = 100 km/s per Mpc). Starburst galaxies cannot account for the reported 100 microns background without extreme evolution at high redshifts. 21 references.

  3. MOIRCS DEEP SURVEY. IV. EVOLUTION OF GALAXY STELLAR MASS FUNCTION BACK TO z {approx} 3

    SciTech Connect

    Kajisawa, M.; Ichikawa, T.; Yamada, T.; Akiyama, M.; Tokoku, C.; Yoshikawa, T.; Tanaka, I.; Suzuki, R.; Konishi, M.; Uchimoto, Y. K.; Ouchi, M.; Iwata, I.; Hamana, T.; Onodera, M.

    2009-09-10

    We use very deep near-infrared (NIR) imaging data obtained in MOIRCS Deep Survey (MODS) to investigate the evolution of the galaxy stellar mass function back to z {approx} 3. The MODS data reach J = 24.2, H = 23.1, and K = 23.1 (5{sigma}, Vega magnitude) over 103 arcmin{sup 2} (wide) and J = 25.1, H = 23.7, and K = 24.1 over 28 arcmin{sup 2} (deep) in the GOODS-North region. The wide and very deep NIR data allow us to measure the number density of galaxies down to low stellar mass (10{sup 9}-10{sup 10} M{sub sun}) even at high redshift with high statistical accuracy. The normalization of the mass function decreases with redshift, and the integrated stellar mass density becomes {approx}8%-18% of the local value at z {approx} 2 and {approx}4%-9% at z {approx} 3, which are consistent with results of previous studies in general fields. Furthermore, we found that the low-mass slope becomes steeper with redshift from {alpha} {approx} -1.3 at z {approx} 1 to {alpha} {approx} -1.6 at z {approx} 3 and that the evolution of the number density of low-mass (10{sup 9}-10{sup 10} M{sub sun}) galaxies is weaker than that of M* ({approx}10{sup 11} M{sub sun}) galaxies. This indicates that the contribution of low-mass galaxies to the total stellar mass density has been significant at high redshift. The steepening of the low-mass slope with redshift is an opposite trend expected from the stellar mass dependence of the specific star formation rate reported in previous studies. The present result suggests that the hierarchical merging process overwhelmed the effect of the stellar mass growth by star formation and was very important for the stellar mass assembly of these galaxies at 1 {approx}< z {approx}< 3.

  4. Enhancing the Legacy of Spitzer and Herschel with the MOSFIRE Deep Evolution Field Survey

    NASA Astrophysics Data System (ADS)

    Reddy, Naveen

    The next frontier for comprehensive galaxy surveys is the epoch at z~1.5-3.5, the peak of star formation and black hole activity. Despite the new windows that Spitzer and Herschel have opened up into the stellar and dust emission of distant galaxies and AGN during this key epoch, these studies have been limited by the lack of spectroscopic redshifts and the unknown physical conditions (e.g., metallicities, ionization) within the targeted galaxies. To realize the full potential of Spitzer and Herschel, we require a large spectroscopic survey that will: (a) efficiently assemble spectroscopic redshifts for large samples of galaxies at z=1.4-3.8; (b) yield the physical conditions, including the ionization and metallicities of these galaxies; and (c) easily obtain spectroscopic redshifts even for very dusty/confused galaxies. To this end, our team has been allocated a large program of 47 Keck nights with the multi-object near-IR spectrograph MOSFIRE to carry out the MOSFIRE Deep Evolution Field Survey (MOSDEF) in three of the Hubble CANDELS fields. MOSDEF will obtain rest-optical spectra of ~1500 galaxies at redshifts z=1.4-3.8, targeting many of the optical nebular emission lines and continuum features (e.g., [OII], [OIII], H-beta, H-alpha, [NII], [SII], 4000 Angstrom break, Ca H and K, and Mbg) that until now have been inaccessible for large samples of distant galaxies, but which are routinely used to measure the SFRs, dust attenuation, metal and gas content, and ionization and dynamical properties in nearby galaxies. MOSDEF spectroscopy provides a critical supporting role for the analysis of Spitzer and Herschel observations of distant galaxies. With this transformative dataset, we will perform the following analyses. First, we will use Spitzer and Herschel imaging, aided with spectroscopic redshifts from MOSDEF, to construct individual and mean dust SEDs for galaxies at redshifts 1.4

  5. CHILES Con Pol: An ultra-deep JVLA survey probing galaxy evolution and cosmic magnetism

    NASA Astrophysics Data System (ADS)

    Hales, Christopher A.; Momjian, Emmanuel; van Gorkom, Jacqueline; Rupen, Michael P.; Greiner, Maksim; Ensslin, Torsten A.; Bonzini, Margherita; Padovani, Paolo; Harrison, Ian; Brown, Michael L.; Gim, Hansung; Yun, Min S.; Maddox, Natasha; Stewart, Adam; Fender, Rob P.; Tremou, Evangelia; Chomiuk, Laura; Peters, Charee; Wilcots, Eric M.; Lazio, Joseph

    2015-08-01

    We are undertaking a 1000 hour campaign with the Karl G. Jansky VLA to survey 0.2 square degrees of the COSMOS field in full polarization continuum at 1.4 GHz. Our observations are part of a joint program with the spectral line COSMOS HI Large Extragalactic Survey (CHILES). When complete, we expect our CHILES Continuum Polarization (CHILES Con Pol) survey to reach an SKA-era sensitivity of 500 nJy per 4 arcsecond resolving beam, the deepest view of the radio sky yet. CHILES Con Pol will open new and fertile parameter space, with sensitivity to star formation rates of 10 Msun per year out to an unprecedented redshift of z=2, and ultra-luminous infrared galaxies and sub-millimeter galaxies out to redshifts of z=8 and beyond. This rich resource will extend the utility of radio band studies beyond the usual radio quasar and radio galaxy populations, opening sensitivity to the starforming and radio-quiet AGN populations that form the bulk of extragalactic sources detected in the optical, X-ray, and infrared bands. In this talk I will outline the key science of CHILES Con Pol, including galaxy evolution and novel measurements of intergalactic magnetic fields. I will present initial results from the first 180 hours of the survey and describe our forthcoming Data Release 1. I invite the astronomical community to consider unique science that can be pursued with CHILES Con Pol radio data.

  6. Tracing Evolution of Starbursts and AGNs using Ultra-deep Radio and mm/smm Surveys

    NASA Astrophysics Data System (ADS)

    Yun, Min S.; Gim, Hansung; Morrison, Glenn; Hales, Christopher A.; Momjian, Emmanuel; Owen, Frazer; Kellermann, Ken; Aretxaga, Itziar; Giavalisco, Mauro; Hughes, David; Lowenthal, James; Miller, Neal; Kawabe, Ryohei; Kohno, Kotaro

    2015-08-01

    There is growing evidence supporting a rapid build up of metals among massive galaxies during their rapid growth via an intense starburst in the early epochs. These star formation activities may be largely obscured in the UV and optical light, as in the local universe. If the growth of supermassive blackholes occurs at or nearly the same time, the accompanying AGN activity may also be heavily obscured. Ultra-deep surveys in the radio and far-infrared can offer extinction-free view of these systems, and the advent of new facilities such as the Jansky VLA, ALMA, and LMT now allows us to probe directly the population of starburst galaxies that are responsible for the bulk of the stellar mass build-up during the epoch of galaxy growth (SFR > 10-100 M⊙/yr at z≈2 or earlier). We will present our analysis of the properties of the micro-Jansky radio sources identified by new Jansky VLA surveys of the GOODS and COSMOS fields using the rich archival data already available (Herschel, Spitzer, Chandra, ALMA, LMT, etc.). Specifically, we find evidence for two populations of microJy radio sources with distinct spectral index distribution. We explore whether this reflects differences in the underlying powering mechanisms by examining their radio-FIR correlation and X-ray properties. We also find the previously reported apparent systematic change in the "q-value" with increasing redshift, and we examine the reality of this trend in some detail. Finally, we will also examine the spatial extent of activities for a subset of the sample where high angular resolution (better than 1") information is available.

  7. The DEEP2 Galaxy Redshift Survey: The Evolution of Void Statistics from z ~ 1 to z ~ 0

    NASA Astrophysics Data System (ADS)

    Conroy, Charlie; Coil, Alison L.; White, Martin; Newman, Jeffrey A.; Yan, Renbin; Cooper, Michael C.; Gerke, Brian F.; Davis, Marc; Koo, David C.

    2005-12-01

    We present measurements of the void probability function (VPF) at z~1 using data from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Redshift Survey and its evolution to z~0 using data from the Sloan Digital Sky Survey (SDSS). We measure the VPF as a function of galaxy color and luminosity in both surveys and find that it mimics trends displayed in the two-point correlation function, ξ: namely, that samples of brighter, red galaxies have larger voids (i.e., are more strongly clustered) than fainter, blue galaxies. We also clearly detect evolution in the VPF with cosmic time, with voids being larger in comoving units at z~0. We find that the reduced VPF matches the predictions of a ``negative binomial'' model for galaxies of all colors, luminosities, and redshifts studied. This model lacks a physical motivation but produces a simple analytic prediction for sources of any number density and integrated two-point correlation function, ξ¯. This implies that differences in the VPF across different galaxy populations are consistent with being due entirely to differences in the population number density and ξ¯. We compare the VPF at z~1 to N-body ΛCDM simulations and find good agreement between the DEEP2 data and mock galaxy catalogs. Interestingly, we find that the dark matter particle reduced VPF follows the physically motivated ``thermodynamic'' model, while the dark matter halo reduced VPF more closely follows the negative binomial model. The robust result that all galaxy populations follow the negative binomial model appears to be due primarily to the clustering of dark matter halos. The reduced VPF is insensitive to changes in the parameters of the halo occupation distribution, in the sense that halo models with the same ξ¯ will produce the same VPF. For the wide range of galaxies studied, the VPF therefore does not appear to provide useful constraints on galaxy evolution models that cannot be gleaned from studies of ξ¯ alone.

  8. The DEEP Groth Strip Survey. VIII. The Evolution of Luminous Field Bulges at Redshift z ~ 1

    NASA Astrophysics Data System (ADS)

    Koo, David C.; Simard, Luc; Willmer, Christopher N. A.; Gebhardt, Karl; Bouwens, Rychard J.; Kauffmann, Guinevere; Crosby, Timothy; Faber, S. M.; Harker, Justin; Sarajedini, Vicki L.; Vogt, Nicole P.; Weiner, Benjamin J.; Phillips, Andrew J.; Im, Myungshin; Wu, K. L.

    2005-04-01

    We present a candidate sample of luminous bulges (including ellipticals) found within the Groth Strip Survey (GSS), with spectroscopic redshifts of 0.73evolution of a single-burst stellar population results in redder colors as the galaxy fades, the observed constancy of very red colors at high redshift suggests more complex histories. One alternative starts with a metal-rich (twice solar), early-formation (z~1.5-2.0) population that is later polluted with small amounts (~4% by total mass) of star formation over an extended period of several Gyr. This ``drizzling'' history is supported by our finding spectroscopic evidence for continued star formation ([O II] emission lines) among 80% of luminous high

  9. Toughening up DELORES: the evolution of the British Antarctic Survey DEep LOok Radio Echo Sounder

    NASA Astrophysics Data System (ADS)

    King, Edward

    2014-05-01

    DELORES is a ground-based radar designed to map the bed and internal structure of thick ice sheets. It is a monopulse radar driven by a ± 2 kV transmitter and using resistively-loaded wire dipole antennae. The recording system is based on a DC-powered digital oscilloscope. All the electronics are housed in weatherproof boxes mounted on sledges and the whole system is towed behind a snowmobile. In the 2013/14 Antarctic field season alone DELORES systems collected over 4000 km of radargrams over ice up to 2.5 km thick. The main operating area has been West Antarctica where surface conditions have varied from deep, soft snow to iron-hard sastrugi. The majority of deployments have been with two-person field teams at locations over 1000 km from support facilities. Therefore the principle design criteria has been 'tough and simple', i.e. make the system robust enough not to break and simple enough to fix with basic tools if it does. Here we describe how the engineering design has evolved over the past eight years and what future developments are planned to achieve greater reliability and versatility.

  10. Size evolution of star-forming galaxies with 2 Deep Survey

    NASA Astrophysics Data System (ADS)

    Ribeiro, B.; Le Fèvre, O.; Tasca, L. A. M.; Lemaux, B. C.; Cassata, P.; Garilli, B.; Maccagni, D.; Zamorani, G.; Zucca, E.; Amorín, R.; Bardelli, S.; Fontana, A.; Giavalisco, M.; Hathi, N. P.; Koekemoer, A.; Pforr, J.; Tresse, L.; Dunlop, J.

    2016-08-01

    Context. The size of a galaxy encapsulates the signature of the different physical processes driving its evolution. The distribution of galaxy sizes in the Universe as a function of cosmic time is therefore a key to understand galaxy evolution. Aims: We aim to measure the average sizes and size distributions of galaxies as they are assembling before the peak in the comoving star formation rate density of the Universe to better understand the evolution of galaxies across cosmic time. Methods: We used a sample of ~1200 galaxies in the COSMOS and ECDFS fields with confirmed spectroscopic redshifts 2 ≤ zspec ≤ 4.5 in the VIMOS Ultra Deep Survey (VUDS), representative of star-forming galaxies with iAB ≤ 25. We first derived galaxy sizes by applying a classical parametric profile-fitting method using GALFIT. We then measured the total pixel area covered by a galaxy above a given surface brightness threshold, which overcomes the difficulty of measuring sizes of galaxies with irregular shapes. We then compared the results obtained for the equivalent circularized radius enclosing 100% of the measured galaxy light r100T ~2.2 to those obtained with the effective radius re,circ measured with GALFIT. Results: We find that the sizes of galaxies computed with our non-parametric approach span a wide range but remain roughly constant on average with a median value r100T ~2.2 kpc for galaxies with 2 evolution of re with increasing redshift, down to sizes of <1 kpc at z ~ 4.5. We analyze the difference and find that parametric fitting of complex, asymmetric, multicomponent galaxies is severely underestimating their sizes. By comparing r100T with physical parameters obtained through fitting the spectral energy distribution we find that the star-forming galaxies that are the largest at any redshift are, on average, more massive and form more stars. We discover that galaxies present more concentrated light profiles with

  11. Deep Extragalactic X-Ray Surveys

    NASA Astrophysics Data System (ADS)

    Brandt, W. N.; Hasinger, G.

    2005-09-01

    Deep surveys of the cosmic X-ray background are reviewed in the context of observational progress enabled by the Chandra X-Ray Observatory and the X-Ray Multi-Mirror Mission-Newton. The sources found by deep surveys are described along with their redshift and luminosity distributions, and the effectiveness of such surveys at selecting active galactic nuclei (AGN) is assessed. Some key results from deep surveys are highlighted, including (a) measurements of AGN evolution and the growth of supermassive black holes, (b) constraints on the demography and physics of high-redshift AGN, (c) the X-ray AGN content of infrared and submillimeter galaxies, and (d) X-ray emission from distant starburst and normal galaxies. We also describe some outstanding problems and future prospects for deep extragalactic X-ray surveys.

  12. The VISTA Deep Extragalactic Observations (VIDEO) Survey

    NASA Astrophysics Data System (ADS)

    Jarvis, M. J.; Häußler, B.; McAlpine, K.

    2013-12-01

    The VIDEO survey is designed to answer key questions regarding the formation and evolution of galaxies, in particular the role of accretion onto black holes and how galaxy evolution may vary depending on environment. VIDEO undertakes deep near-infrared imaging over three well-observed extragalactic fields allowing in-depth study of galaxy evolution over 1 < z < 4, linking the shallower VST and VISTA surveys with the UltraVISTA survey. The area and depth of the VIDEO survey enables the detection of the bulk of the luminosity density arising from galaxies over 90% of the history of the Universe, as well as the most massive galaxies at all epochs and any associated accretion activity. A few scientific highlights from the early VIDEO data are provided.

  13. The evolution of the near-infrared galaxy luminosity function and colour bimodality up to z ~= 2 from the UKIDSS Ultra Deep Survey Early Data Release

    NASA Astrophysics Data System (ADS)

    Cirasuolo, M.; McLure, R. J.; Dunlop, J. S.; Almaini, O.; Foucaud, S.; Smail, Ian; Sekiguchi, K.; Simpson, C.; Eales, S.; Dye, S.; Watson, M. G.; Page, M. J.; Hirst, P.

    2007-09-01

    We present new results on the cosmological evolution of the near-infrared (near-IR) galaxy luminosity function (LF), derived from the analysis of a new sample of ~22000KAB <= 22.5 galaxies selected over an area of 0.6 deg2 from the Early Data Release of the UKIDSS Ultra Deep Survey (UDS). Our study has exploited the multiwavelength coverage of the UDS field provided by the new UKIDSS WFCAM K- and J-band imaging, the Subaru/XMM-Newton Deep Survey and the Spitzer Wide-Area Infrared Extragalactic survey. The unique combination of large area and depth provided by this new survey minimizes the complicating effect of cosmic variance and has allowed us, for the first time, to trace the evolution of the brightest sources out to z ~= 2 with good statistical accuracy. In agreement with previous studies, we find that the characteristic luminosity of the near-IR LF brightens by ~=1 mag between z = 0 and z ~= 2, while the total density decreases by a factor of ~=2. Using the rest-frame (U - B) colour to split the sample into red and blue galaxies, we confirm the classic luminosity-dependent colour bimodality at z <~ 1. However, the strength of the colour bimodality is found to be a decreasing function of redshift, and seems to disappear by z >~ 1.5. Due to the large size of our sample, we are able to investigate the differing cosmological evolution of the red and blue galaxy populations. It is found that the space density of the brightest red galaxies (MK <= - 23) stays approximately constant with redshift, and that these sources dominate the bright end of the LF at redshifts z <~ 1. In contrast, the brightening of the characteristic luminosity and mild decrease in space density displayed by the blue galaxy population leads them to dominate the bright end of the LF at redshifts z >~ 1.

  14. CHILES Con Pol: Probing galaxy evolution, the dark Universe, and cosmic magnetism with a deep 1000 hour Jansky VLA survey

    NASA Astrophysics Data System (ADS)

    Hales, Christopher A.; Chiles Con Pol Collaboration

    2014-04-01

    We recently started a 1000 hour campaign to observe 0.2 square degrees of the COSMOS field in full polarization continuum at 1.4 GHz with the Jansky VLA, as part of a joint program with the spectral line COSMOS HI Large Extragalactic Survey (CHILES). When complete, we expect our CHILES Continuum Polarization (CHILES Con Pol) survey to reach an unprecedented SKA-era sensitivity of 0.7 uJy per 4 arcsecond FWHM beam. Here we present the key goals of CHILES Con Pol, which are to (i) produce a source catalog of legacy value to the astronomical community, (ii) measure differential source counts in total intensity, linear polarization, and circular polarization in order to constrain the redshift and luminosity distributions of source populations, (iii) perform a novel weak lensing study using radio polarization as an indicator of intrinsic alignment to better study dark energy and dark matter, and (iv) probe the unknown origin of cosmic magnetism by measuring the strength and structure of intergalactic magnetic fields in the filaments of large scale structure. The CHILES Con Pol source catalog will be a useful resource for upcoming wide-field surveys by acting as a training set for machine learning algorithms, which can then be used to identify and classify radio sources in regions lacking deep multiwavelength coverage.

  15. Evolution of star formation in the UKIDSS Ultra Deep Survey field - I. Luminosity functions and cosmic star formation rate out to z = 1.6

    NASA Astrophysics Data System (ADS)

    Drake, Alyssa B.; Simpson, Chris; Collins, Chris A.; James, Phil A.; Baldry, Ivan K.; Ouchi, Masami; Jarvis, Matt J.; Bonfield, David G.; Ono, Yoshiaki; Best, Philip N.; Dalton, Gavin B.; Dunlop, James S.; McLure, Ross J.; Smith, Daniel J. B.

    2013-07-01

    We present new results on the cosmic star formation history in the Subaru/XMM-Newton Deep Survey (SXDS)-Ultra Deep Survey (UDS) field out to z = 1.6. We compile narrow-band data from the Subaru Telescope and the Visible and Infrared Survey Telescope for Astronomy (VISTA) in conjunction with broad-band data from the SXDS and UDS, to make a selection of 5725 emission-line galaxies in 12 redshift slices, spanning 10 Gyr of cosmic time. We determine photometric redshifts for the sample using 11-band photometry, and use a spectroscopically confirmed subset to fine tune the resultant redshift distribution. We use the maximum-likelihood technique to determine luminosity functions in each redshift slice and model the selection effects inherent in any narrow-band selection statistically, to obviate the retrospective corrections ordinarily required. The deep narrow-band data are sensitive to very low star formation rates (SFRs), and allow an accurate evaluation of the faint end slope of the Schechter function, α. We find that α is particularly sensitive to the assumed faintest broad-band magnitude of a galaxy capable of hosting an emission line, and propose that this limit should be empirically motivated. For this analysis, we base our threshold on the limiting observed equivalent widths of emission lines in the local Universe. We compute the characteristic SFR of galaxies in each redshift slice, and the integrated SFR density, ρSFR. We find our results to be in good agreement with the literature and parametrize the evolution of the SFR density as ρSFR ∝ (1 + z)4.58 confirming a steep decline in star formation activity since z ˜ 1.6.

  16. ESO imaging survey: infrared deep public survey

    NASA Astrophysics Data System (ADS)

    Olsen, L. F.; Miralles, J.-M.; da Costa, L.; Madejsky, R.; Jørgensen, H. E.; Mignano, A.; Arnouts, S.; Benoist, C.; Dietrich, J. P.; Slijkhuis, R.; Zaggia, S.

    2006-09-01

    This paper is part of the series presenting the final results obtained by the ESO Imaging Survey (EIS) project. It presents new J and Ks data obtained from observations conducted at the ESO 3.5 m New Technology Telescope (NTT) using the SOFI camera. These data were taken as part of the Deep Public Survey (DPS) carried out by the ESO Imaging Survey program, significantly extending the earlier optical/infrared EIS-DEEP survey presented in a previous paper of this series. The DPS-IR survey comprises two observing strategies: shallow Ks observations providing nearly full coverage of pointings with complementary multi-band (in general {UBVRI}) optical data obtained using ESO's wide-field imager (WFI) and deeper J and Ks observations of the central parts of these fields. Currently, the DPS-IR survey provides a coverage of roughly 2.1 square degrees ( 300 SOFI pointings) in Ks with 0.63 square degrees to fainter magnitudes and also covered in J, over three independent regions of the sky. The goal of the present paper is to briefly describe the observations, the data reduction procedures, and to present the final survey products which include fully calibrated pixel-maps and catalogs extracted from them. The astrometric solution with an estimated accuracy of ⪉0.15 arcsec is based on the USNO catalog and limited only by the accuracy of the reference catalog. The final stacked images presented here number 89 and 272, in J and K_s, respectively, the latter reflecting the larger surveyed area. The J and Ks images were taken with a median seeing of 0.77 arcsec and 0.8 arcsec. The images reach a median 5σ limiting magnitude of JAB˜23.06 as measured within an aperture of 2´´, while the corresponding limiting magnitude in KsAB is 21.41 and 22.16 mag for the shallow and deep strategies. Although some spatial variation due to varying observing conditions is observed, overall the observed limiting magnitudes are consistent with those originally proposed. The quality of the data

  17. Deep multicolor surveys of the galaxy population

    NASA Astrophysics Data System (ADS)

    Szokoly, Gyula Pal

    1999-10-01

    I present various surveys that benefit from the tremendous improvements in observational astronomy in recent years and I develop new techniques to analyze data obtained in these new generation of surveys. In participation of upcoming, very deep near-infrared galaxy surveys, I constructed a survey aimed at determining the near-infrared luminosity function of galaxies. The evolutionary effects are much weaker at the red end of the atmospheric window ranging from the near- ultraviolet to about 2.2 μ m than in the optical and UV bands, as the infrared light coming from a galaxy is dominated by the old stellar population, while optical luminosity is strongly affected by the star formation history of galaxies. Measuring the luminosity function of galaxies is essential to interpret future surveys. Utilizing my deep, large area, multi-color optical galaxy survey, I studied the structure evolution of the Universe on cosmologically relevant scales. The multicolor nature of the survey (B, V, R and I bands) made it possible to estimate the radial distance to a very large number of galaxies very efficiently. Using these photometric redshifts, one can reduce the effects of galaxy evolution by analyzing galaxies at roughly the same redshift (lookback time). Due to the large area (about 1.5 square degrees) and very faint limiting magnitude (I = 23.8), structure evolution can be studied with a very high precision. I also propose a new object detection technique to replace traditional methods that use a single band or an arbitrarily co-added image. Our new technique uses all available bands of a survey and provides a nearly optimal way to take advantage of all the information available. We demonstrate the strength of this technique using the Hubble Deep Field, where we show that we can extend the detection limit significantly. We also show that this method can identify a significant number of objects that traditional techniques usually can not detect. Finally I propose a new

  18. The VISTA Deep Extragalactic Observations (VIDEO) Survey

    NASA Astrophysics Data System (ADS)

    Bonfield, David G.; Jarvis, M. J.; VIDEO Consortium

    2010-01-01

    The VISTA Deep Extragalactic Observations (VIDEO) survey is a 12 sq. degree, Z,Y,J,H,Ks survey, to be carried out with the new ESO Visible and Infrared Survey Telescope for Astronomy (VISTA). The survey is specifically designed to enable galaxy and cluster/structure evolution to be traced as a function of both epoch and environment from the present day out to redshift z=4, and AGN and the most massive galaxies up to and into the epoch of reionization. With its depth and area, VIDEO will be able to fully probe the epoch of activity in the Universe, where AGN and starburst activity were at their peak and the first galaxy clusters were beginning to virialise. VIDEO therefore offers a unique data set with which to investigate the interplay between AGN, starbursts and environment, and the role of feedback at a time when it is most crucial. The three survey fields (ELAIS-S1, XMM-LSS, and CDF-S) have been chosen to maximise overlap with complementary multiwavelength data, and, as an ESO public survey, for future follow-up from southern facilities including the VLT, APEX, and ALMA. We have also recently established an agreement with the Dark Energy Survey Supernova Survey which will allow rest-frame optical light curves to be measured for distant supernovae, thus negating some of the biases inherent to optical surveys.

  19. Oceanic crust deep seismic survey

    NASA Astrophysics Data System (ADS)

    McBride, J. H.; White, R. S.

    In September 1991, the British Institutions Reflection Profiling Syndicate (BIRPS) collected 578 km of deep seismic reflection profiles over the oceanic crust beneath the Cape Verde abssyal plain in approximately 4900 m of water (Fig. 1). The survey, under the direction of J. H. McBride, was undertaken in response to a proposal made by R. S. White at the 1990 BIRPS open syndicate meeting in Birmingham, England, and was acquired using GECO-PRAKLA'S M/V Bin Hai 511. The survey consisted of two strike lines parallel to magnetic sea-floor lineations and nine orthogonal crossing lines oriented parallel to the spreading direction (Fig. 2). Adjacent lines are spaced at 4 km. For the first time, this provides the ability to map oceanic crust in “3D,” since the line spacing is less than or equal to the Fresnel-zone diameter for the lower crust.

  20. The MOSFIRE Deep Evolution Field (MOSDEF) Survey: Rest-frame Optical Spectroscopy for ~1500 H-selected Galaxies at 1.37 < z < 3.8

    NASA Astrophysics Data System (ADS)

    Kriek, Mariska; Shapley, Alice E.; Reddy, Naveen A.; Siana, Brian; Coil, Alison L.; Mobasher, Bahram; Freeman, William R.; de Groot, Laura; Price, Sedona H.; Sanders, Ryan; Shivaei, Irene; Brammer, Gabriel B.; Momcheva, Ivelina G.; Skelton, Rosalind E.; van Dokkum, Pieter G.; Whitaker, Katherine E.; Aird, James; Azadi, Mojegan; Kassis, Marc; Bullock, James S.; Conroy, Charlie; Davé, Romeel; Kereš, Dušan; Krumholz, Mark

    2015-06-01

    In this paper we present the MOSFIRE Deep Evolution Field (MOSDEF) survey. The MOSDEF survey aims to obtain moderate-resolution (R = 3000-3650) rest-frame optical spectra (˜3700-7000 Å) for ˜1500 galaxies at 1.37≤ z≤ 3.80 in three well-studied CANDELS fields: AEGIS, COSMOS, and GOODS-N. Targets are selected in three redshift intervals: 1.37≤ z≤ 1.70, 2.09≤ z≤ 2.61, and 2.95≤ z≤ 3.80, down to fixed {H}{AB} (F160W) magnitudes of 24.0, 24.5, and 25.0, respectively, using the photometric and spectroscopic catalogs from the 3D-HST survey. We target both strong nebular emission lines (e.g., [O ii] λ λ 3727,3730, Hβ, [O iii] λ λ 4960,5008, Hα, [N ii] λ λ 6550,6585, and [S ii] λ λ 6718,6733) and stellar continuum and absorption features (e.g., Balmer lines, Ca-ii H and K, Mgb, 4000 Å break). Here we present an overview of our survey, the observational strategy, the data reduction and analysis, and the sample characteristics based on spectra obtained during the first 24 nights. To date, we have completed 21 masks, obtaining spectra for 591 galaxies. For ˜80% of the targets we derive a robust redshift from either emission or absorption lines. In addition, we confirm 55 additional galaxies, which were serendipitously detected. The MOSDEF galaxy sample includes unobscured star-forming, dusty star-forming, and quiescent galaxies and spans a wide range in stellar mass (˜ {10}9-{10}11.5 {M}⊙ ) and star formation rate (˜ {10}0-{10}3 {M}⊙ {{yr}}-1). The spectroscopically confirmed sample is roughly representative of an H-band limited galaxy sample at these redshifts. With its large sample size, broad diversity in galaxy properties, and wealth of available ancillary data, MOSDEF will transform our understanding of the stellar, gaseous, metal, dust, and black hole content of galaxies during the time when the universe was most active.

  1. Galaxy formation from deep surveys with Herschel-PACS

    NASA Astrophysics Data System (ADS)

    Lutz, D.

    2011-11-01

    Deep far-infrared photometric surveys studying galaxy evolution and the nature of the cosmic infrared background are a key strength of the Herschel mission. The PACS Evolutionary Probe (PEP) guaranteed time key program obtains deep photometric surveys of some of the key extragalactic multiwavelength fields at wavelengths between 70 and 160 μm. This contribution gives an overview of first science results, illustrating the potential of Herschel in providing calorimetric star formation rates for various high redshift galaxy populations, thus testing and superseding previous extrapolations from other wavelengths, and enabling a wide range of galaxy evolution studies.

  2. The properties and evolution of a K-band selected sample of massive galaxies at z ~ 0.4-2 in the Palomar/DEEP2 survey

    NASA Astrophysics Data System (ADS)

    Conselice, C. J.; Bundy, K.; Trujillo, I.; Coil, A.; Eisenhardt, P.; Ellis, R. S.; Georgakakis, A.; Huang, J.; Lotz, J.; Nandra, K.; Newman, J.; Papovich, C.; Weiner, B.; Willmer, C.

    2007-11-01

    We present the results of a study on the properties and evolution of massive (M* > 1011Msolar) galaxies at z ~ 0.4-2 utilizing Keck spectroscopy, near-infrared Palomar imaging, and Hubble, Chandra and Spitzer data covering fields targeted by the DEEP2 galaxy spectroscopic survey. Our sample is K-band selected and stellar mass limited, based on wide-area near-infrared imaging from the Palomar Observatory Wide-Field Infrared Survey, which covers 1.53 deg2 to a 5σ depth of Ks,vega ~ 20.5. Our primary goal is to obtain a broad census of massive galaxies through measuring how their number and mass densities, morphology, as well as their star formation and active galactic nucleus content evolve from z ~ 0.4-2. Our major findings include: (i) statistically the mass and number densities of M* > 1011Msolar galaxies show little evolution between z = 0 and 1 and from z ~ 0 to 2 for M* > 1011.5Msolar galaxies. We however find significant evolution within 1 < z < 1.5 for 1011 Msolar < M* < 1011.5Msolar galaxies. (ii) After examining the structures of our galaxies using Hubble ACS imaging, we find that M* > 1011Msolar selected galaxies show a nearly constant elliptical fraction of ~70-90 per cent at all redshifts. The remaining objects tend to be peculiars possibly undergoing mergers at z > 0.8, while spirals dominate the remainder at lower redshifts. A significant fraction (~25 per cent) of these early-types contain minor structural anomalies. (iii) We find that only a fraction (~60 per cent) of massive galaxies with M* > 1011Msolar are on the red sequence at z ~ 1.4, while nearly 100 per cent evolve on to it by z ~ 0.4. (iv) By utilizing Spitzer MIPS imaging and [OII] line fluxes we argue that M* > 1011.5Msolar galaxies have a steeply declining star formation rate (SFR) density ~ (1 + z)6. By examining the contribution of star formation to the evolution of the mass function, as well as the merger history through the CAS parameters, we determine that M* > 1011Msolar galaxies

  3. Evolution of clustering length, large-scale bias, and host halo mass at 2 < z < 5 in the VIMOS Ultra Deep Survey (VUDS)⋆

    NASA Astrophysics Data System (ADS)

    Durkalec, A.; Le Fèvre, O.; Pollo, A.; de la Torre, S.; Cassata, P.; Garilli, B.; Le Brun, V.; Lemaux, B. C.; Maccagni, D.; Pentericci, L.; Tasca, L. A. M.; Thomas, R.; Vanzella, E.; Zamorani, G.; Zucca, E.; Amorín, R.; Bardelli, S.; Cassarà, L. P.; Castellano, M.; Cimatti, A.; Cucciati, O.; Fontana, A.; Giavalisco, M.; Grazian, A.; Hathi, N. P.; Ilbert, O.; Paltani, S.; Ribeiro, B.; Schaerer, D.; Scodeggio, M.; Sommariva, V.; Talia, M.; Tresse, L.; Vergani, D.; Capak, P.; Charlot, S.; Contini, T.; Cuby, J. G.; Dunlop, J.; Fotopoulou, S.; Koekemoer, A.; López-Sanjuan, C.; Mellier, Y.; Pforr, J.; Salvato, M.; Scoville, N.; Taniguchi, Y.; Wang, P. W.

    2015-11-01

    We investigate the evolution of galaxy clustering for galaxies in the redshift range 2.0 Deep Survey (VUDS). We present the projected (real-space) two-point correlation function wp(rp) measured by using 3022 galaxies with robust spectroscopic redshifts in two independent fields (COSMOS and VVDS-02h) covering in total 0.8deg2. We quantify how the scale dependent clustering amplitude r0 changes with redshift making use of mock samples to evaluate and correct the survey selection function. Using a power-law model ξ(r) = (r/r0)- γ we find that the correlation function for the general population is best fit by a model with a clustering length r0 = 3.95+0.48-0.54 h-1 Mpc and slope γ = 1.8+0.02-0.06 at z ~ 2.5, r0 = 4.35 ± 0.60 h-1 Mpc and γ = 1.6+0.12-0.13 at z ~ 3.5. We use these clustering parameters to derive the large-scale linear galaxy bias bLPL, between galaxies and dark matter. We find bLPL = 2.68 ± 0.22 at redshift z ~ 3 (assuming σ8 = 0.8), significantly higher than found at intermediate and low redshifts for the similarly general galaxy populations. We fit a halo occupation distribution (HOD) model to the data and we obtain that the average halo mass at redshift z ~ 3 is Mh = 1011.75 ± 0.23 h-1M⊙. From this fit we confirm that the large-scale linear galaxy bias is relatively high at bLHOD = 2.82 ± 0.27. Comparing these measurements with similar measurements at lower redshifts we infer that the star-forming population of galaxies at z ~ 3 should evolve into the massive and bright (Mr< -21.5)galaxy population, which typically occupy haloes of mass ⟨ Mh ⟩ = 1013.9 h-1M⊙ at redshift z = 0. Based on data obtained with the European Southern Observatory Very Large Telescope, Paranal, Chile, under Large Program 185.A-0791.Appendices are available in electronic form at http://www.aanda.org

  4. The VISTA Deep Extragalactic Observations (VIDEO) survey

    NASA Astrophysics Data System (ADS)

    Jarvis, Matt J.; Bonfield, D. G.; Bruce, V. A.; Geach, J. E.; McAlpine, K.; McLure, R. J.; González-Solares, E.; Irwin, M.; Lewis, J.; Yoldas, A. Kupcu; Andreon, S.; Cross, N. J. G.; Emerson, J. P.; Dalton, G.; Dunlop, J. S.; Hodgkin, S. T.; Le, Fèvre O.; Karouzos, M.; Meisenheimer, K.; Oliver, S.; Rawlings, S.; Simpson, C.; Smail, I.; Smith, D. J. B.; Sullivan, M.; Sutherland, W.; White, S. V.; Zwart, J. T. L.

    2013-01-01

    In this paper, we describe the first data release of the Visible and Infrared Survey Telescope for Astronomy (VISTA) Deep Extragalactic Observations (VIDEO) survey. VIDEO is a ˜12 deg2 survey in the near-infrared Z, Y, J, H and Ks bands, specifically designed to enable the evolution of galaxies and large structures to be traced as a function of both epoch and environment from the present day out to z = 4, and active galactic nuclei (AGNs) and the most massive galaxies up to and into the epoch of reionization. With its depth and area, VIDEO will be able to fully explore the period in the Universe where AGN and starburst activity were at their peak and the first galaxy clusters were beginning to virialize. VIDEO therefore offers a unique data set with which to investigate the interplay between AGN, starbursts and environment, and the role of feedback at a time when it was potentially most crucial. We provide data over the VIDEO-XMM3 tile, which also covers the Canada-France-Hawaii Telescope Legacy Survey Deep-1 field (CFHTLS-D1). The released VIDEO data reach a 5σ AB-magnitude depth of Z = 25.7, Y = 24.5, J = 24.4, H = 24.1 and Ks = 23.8 in 2 arcsec diameter apertures (the full depth of Y = 24.6 will be reached within the full integration time in future releases). The data are compared to previous surveys over this field and we find good astrometric agreement with the Two Micron All Sky Survey, and source counts in agreement with the recently released UltraVISTA survey data. The addition of the VIDEO data to the CFHTLS-D1 optical data increases the accuracy of photometric redshifts and significantly reduces the fraction of catastrophic outliers over the redshift range 0 < z < 1 from 5.8 to 3.1 per cent in the absence of an i-band luminosity prior. However, we expect that the main improvement in photometric redshifts will come in the redshift range 1 < z < 4 due to the sensitivity to the Balmer and 4000 Å breaks provided by the near-infrared VISTA filters. All

  5. The BMW Deep X-ray Cluster Survey

    NASA Astrophysics Data System (ADS)

    Moretti, A.; Guzzo, L.; Campana, S.; Covino, S.; Lazzati, D.; Longhetti, M.; Molinari, E.; Panzera, M. R.; Tagliaferri, G.; dell'Antonio, I.

    We describe the main features of the BMW survey of serendipitous X-ray clusters, based on the still unexploited ROSAT-HRI archival observations. The sky coverage, surface density and first deep optical CCD images of the candidates indicate that this sample can represent an excellent complement to the existing PSPC deep cluster surveys and will provide us with a fully independent probe of the evolution of the cluster abundance, in addition to significantly increasing the number of clusters known at z>0.6.

  6. Accelerated Evolution of the Lyα Luminosity Function at z >~ 7 Revealed by the Subaru Ultra-deep Survey for Lyα Emitters at z = 7.3

    NASA Astrophysics Data System (ADS)

    Konno, Akira; Ouchi, Masami; Ono, Yoshiaki; Shimasaku, Kazuhiro; Shibuya, Takatoshi; Furusawa, Hisanori; Nakajima, Kimihiko; Naito, Yoshiaki; Momose, Rieko; Yuma, Suraphong; Iye, Masanori

    2014-12-01

    We present the ultra-deep Subaru narrowband imaging survey for Lyα emitters (LAEs) at z = 7.3 in the Subaru/XMM-Newton Deep Survey (SXDS) and Cosmic Evolution Survey (COSMOS) fields (~0.5 deg2) with a total integration time of 106 hr. Exploiting our new sharp bandwidth filter, NB101, installed on the Suprime-Cam, we have reached L(Lyα) = 2.4 × 1042 erg s-1 (5σ) for z = 7.3 LAEs, about four times deeper than previous Subaru z >~ 7 studies, which allows us to reliably investigate the evolution of the Lyα luminosity function (LF) for the first time down to the luminosity limit same as those of Subaru z = 3.1-6.6 LAE samples. Surprisingly, we only find three and four LAEs in the SXDS and COSMOS fields, respectively, while one expects a total of ~65 LAEs by our survey in the case of no Lyα LF evolution from z = 6.6 to 7.3. We identify a decrease of the Lyα LF from z = 6.6 to 7.3 at the >90% confidence level from our z = 7.3 Lyα LF with the best-fit Schechter parameters of L*{Lyα } = 2.7+8.0-1.2 × 1042 {erg} {s}-1 and φ * = 3.7+17.6-3.3 × 10-4 {Mpc}-3 for a fixed α = -1.5. Moreover, the evolution of the Lyα LF is clearly accelerated at z > 6.6 beyond the measurement uncertainties including cosmic variance. Because no such accelerated evolution of the UV-continuum LF or the cosmic star formation rate (SFR) is found at z ~ 7, but suggested only at z > 8, this accelerated Lyα LF evolution is explained by physical mechanisms different from a pure SFR decrease but related to the Lyα production and escape in the process of cosmic reionization. Because a simple accelerating increase of intergalactic medium neutral hydrogen absorbing Lyα cannot be reconciled with Thomson scattering of optical depth measurements from WMAP and Planck, our findings may support new physical pictures suggested by recent theoretical studies, such as the existence of HI clumpy clouds within cosmic ionized bubbles that are selectively absorbing Lyα and the large ionizing photon escape

  7. MOIRCS DEEP SURVEY. VIII. EVOLUTION OF STAR FORMATION ACTIVITY AS A FUNCTION OF STELLAR MASS IN GALAXIES SINCE z {approx} 3

    SciTech Connect

    Kajisawa, M.; Ichikawa, T.; Yamada, T.; Akiyama, M.; Uchimoto, Y. K.; Yoshikawa, T.; Onodera, M.

    2010-11-01

    We study the evolution of star formation activity of galaxies at 0.5 < z < 3.5 as a function of stellar mass, using very deep NIR data taken with the Multi-Object Infrared Camera and Spectrograph on the Subaru telescope in the GOODS-North region. The NIR imaging data reach K{approx} 23-24 Vega magnitude and they allow us to construct a nearly stellar-mass-limited sample down to {approx}10{sup 9.5-10} M{sub sun} even at z {approx} 3. We estimated star formation rates (SFRs) of the sample with two indicators, namely, the Spitzer/MIPS 24 {mu}m flux and the rest-frame 2800 A luminosity. The SFR distribution at a fixed M{sub star} shifts to higher values with increasing redshift at 0.5 < z < 3.5. More massive galaxies show stronger evolution of SFR at z {approx}> 1. We found galaxies at 2.5 < z < 3.5 show a bimodality in their SSFR distribution, which can be divided into two populations by a constant SSFR of {approx}2 Gyr{sup -1}. Galaxies in the low-SSFR group have SSFRs of {approx}0.5-1.0 Gyr{sup -1}, while the high-SSFR population shows {approx}10 Gyr{sup -1}. The cosmic SFR density (SFRD) is dominated by galaxies with M{sub star} = 10{sup 10-11} M{sub sun} at 0.5 < z < 3.5, while the contribution of massive galaxies with M{sub star} = 10{sup 11-11.5} M{sub sun} shows a strong evolution at z>1 and becomes significant at z {approx} 3, especially in the case with the SFR based on MIPS 24 {mu}m. In galaxies with M{sub star} = 10{sup 10-11.5} M{sub sun}, those with a relatively narrow range of SSFR ({approx}<1 dex) dominates the cosmic SFRD at 0.5 < z < 3.5. The SSFR of galaxies that dominate the SFRD systematically increases with redshift. At 2.5 < z < 3.5, the high-SSFR population, which is relatively small in number, dominates the SFRD. Major star formation in the universe at higher redshift seems to be associated with a more rapid growth of stellar mass of galaxies.

  8. The ALFA ZOA Deep Survey: First Results

    NASA Astrophysics Data System (ADS)

    McIntyre, T. P.; Henning, P. A.; Minchin, R. F.; Momjian, E.; Butcher, Z.

    2015-07-01

    The Arecibo L-band Feed Array Zone of Avoidance (ALFA ZOA) Deep Survey is the deepest and most sensitive blind H i survey undertaken in the ZOA. ALFA ZOA Deep will cover about 300 square degrees of sky behind the Galactic Plane in both the inner (30^\\circ ≤slant l≤slant 75^\\circ ;b≤slant | 2^\\circ | ) and outer (175^\\circ ≤slant l≤slant 207^\\circ ;-2^\\circ ≤slant b≤slant +1^\\circ ) Galaxy, using the Arecibo Radio Telescope. First results from the survey have found 61 galaxies within a 15 square degree area centered on l=192^\\circ and b = -2°. The survey reached its expected sensitivity of rms = 1 mJy at 9 km s-1 channel resolution, and is shown to be complete above integrated flux, FHi = 0.5 Jy km s-1. The positional accuracy of the survey is 28″ and detections are found out to a recessional velocity of nearly 19,000 km s-1. The survey confirms the extent of the Orion and Abell 539 clusters behind the plane of the Milky Way and discovers expansive voids, at 10,000 and 18,000 km s-1. Twenty-six detections (43%) have a counterpart in the literature, but only two of these have known redshifts. Counterparts are 20% less common beyond vhel = 10,000 km s-1 and 33% less common at extinctions higher than AB = 3.5 mag. The ALFA ZOA Deep survey is able to probe large scale structure beyond redshifts that even the most modern wide-angle surveys have been able to detect in the ZOA at any wavelength.

  9. Pan-STARRS-1 Medium Deep Survey

    NASA Astrophysics Data System (ADS)

    Huber, Mark

    2015-08-01

    The Panoramic Survey Telescope And Rapid Response System-1 (Pan-STARRS-1, PS1) has been in full science operation since Spring 2010 and concluded the observing program for the PS1 Science Consortium (PS1SC) in early 2014. The Medium Deep Survey (MDS) component of the program regularly visited 10 fields (~7 sq. deg. each) with significant multi-wavelength overlap from previous and concurrent surveys (e.g. SDSS, DEEP2, CDFS, COSMOS, GALEX) for 25% of the total time allocation. The cadence generally includes the g,r,i,z filters for a MDS field every 3 days over the 6-8 month season the field is visible, with the y filter done primarily during bright time. The nightly stacks of eight exposures typically reach depths of r,i~23.5 mag. Development work continued to improve the single exposure processing though to deep stacks during the transient event discovery and other science consortium programs over the course of the survey, the culmination of those improvements being applied in a more uniformly reprocessed dataset used for the public data release. A summary of the MDS public data release products will be presented.For details on PS1 and the Science Collaboration, visit http://ps1sc.org/

  10. Microclimate controls on weathering: Insights into deep critical zone evolution from seismic refraction surveys in the Susquehanna Shale Hills Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    West, N.; Kirby, E.; Nyblade, A.; Brantley, S. L.; Clarke, B. A.

    2015-12-01

    The formation of regolith is fundamental to the functioning and structure of the critical zone - the physically and chemically altered material formed from in situ parent bedrock that is available for transport. Understanding how regolith production and transport respond to perturbations in climate and/or tectonic forcing remains a first-order question. At the Susquehanna Shale Hills Critical Zone Observatory (SSHO), high resolution LiDAR-derived topographic data and depths to hand auger refusal reveal a systematic asymmetry in hillslope gradient and mobile regolith thickness; both are greater on north-facing hillslopes. Hydrologic and geochemical studies at the SSHO also suggest asymmetric sediment transport, fluid flow, and mineral weathering with respect to hillslope aspect. Here, we combine shallow seismic surveys completed along 4 hillslope transects (2 north-facing and 2-south facing), 2 ridgetops transects, and subsurface observations in boreholes to investigate the role of climate in inducing fracturing and priming the development of the observed asymmetry. Comparisons of shallow p-wave velocities with borehole and pit observations lead us to hypothesize the presence of three distinct layers at SSHO: 1) a deep, high velocity layer that is consistent with unweathered shale bedrock; 2) an intermediate velocity layer that is consistent with fractured and chemically altered bedrock which overlies unaltered bedrock, and 3) a shallow, slow velocity layer that is consistent with mobile material or shallow soil. Shallow p-wave velocity profiles suggest differences in thickness for both the mobile and immobile regolith material with respect to aspect. Patterns of p-wave velocities with depth are consistent with patterns of fracture densities observed in boreholes and with predictive cracking intensity models related to frost action. The models and data are consistent with climate as a primary driver for the development of asymmetry in the subsurface architecture at

  11. DeepSurveyCam—A Deep Ocean Optical Mapping System

    PubMed Central

    Kwasnitschka, Tom; Köser, Kevin; Sticklus, Jan; Rothenbeck, Marcel; Weiß, Tim; Wenzlaff, Emanuel; Schoening, Timm; Triebe, Lars; Steinführer, Anja; Devey, Colin; Greinert, Jens

    2016-01-01

    Underwater photogrammetry and in particular systematic visual surveys of the deep sea are by far less developed than similar techniques on land or in space. The main challenges are the rough conditions with extremely high pressure, the accessibility of target areas (container and ship deployment of robust sensors, then diving for hours to the ocean floor), and the limitations of localization technologies (no GPS). The absence of natural light complicates energy budget considerations for deep diving flash-equipped drones. Refraction effects influence geometric image formation considerations with respect to field of view and focus, while attenuation and scattering degrade the radiometric image quality and limit the effective visibility. As an improvement on the stated issues, we present an AUV-based optical system intended for autonomous visual mapping of large areas of the seafloor (square kilometers) in up to 6000 m water depth. We compare it to existing systems and discuss tradeoffs such as resolution vs. mapped area and show results from a recent deployment with 90,000 mapped square meters of deep ocean floor. PMID:26828495

  12. DeepSurveyCam--A Deep Ocean Optical Mapping System.

    PubMed

    Kwasnitschka, Tom; Köser, Kevin; Sticklus, Jan; Rothenbeck, Marcel; Weiß, Tim; Wenzlaff, Emanuel; Schoening, Timm; Triebe, Lars; Steinführer, Anja; Devey, Colin; Greinert, Jens

    2016-01-01

    Underwater photogrammetry and in particular systematic visual surveys of the deep sea are by far less developed than similar techniques on land or in space. The main challenges are the rough conditions with extremely high pressure, the accessibility of target areas (container and ship deployment of robust sensors, then diving for hours to the ocean floor), and the limitations of localization technologies (no GPS). The absence of natural light complicates energy budget considerations for deep diving flash-equipped drones. Refraction effects influence geometric image formation considerations with respect to field of view and focus, while attenuation and scattering degrade the radiometric image quality and limit the effective visibility. As an improvement on the stated issues, we present an AUV-based optical system intended for autonomous visual mapping of large areas of the seafloor (square kilometers) in up to 6000 m water depth. We compare it to existing systems and discuss tradeoffs such as resolution vs. mapped area and show results from a recent deployment with 90,000 mapped square meters of deep ocean floor. PMID:26828495

  13. Pan-STARRS-1 Medium Deep Survey

    NASA Astrophysics Data System (ADS)

    Huber, Mark; PS1-IPP Team, PS1 Science Consortium

    2015-01-01

    The Panoramic Survey Telescope And Rapid Response System-1 (Pan-STARRS-1, PS1) has been in full operation since Spring 2010 and concluded the PS1 Science Consortium (PS1SC) observational program in early 2014. The Medium Deep Survey (MDS) component of the program, allocated 25% of the time, regularly visited 10 fields (~7 sq. deg. each) with significant multi-wavelength overlap from previous and concurrent surveys (e.g. SDSS, DEEP2, CDFS, COSMOS, GALEX). The cadence generally includes the g,r,i,z filters for a MDS field every 3 days with a nightly stack depth of r,i~23.5 mag and the y filter primarily during bright time over the 6-8 month season the field is visible. While regularly producing data for the transient event discovery and science consortium programs, development work continued to improve the single exposures though production of deep stacks for reprocessing into the final and public release. The data products, to be publicly available after the post-observing proprietary period, will be summarized.For details on PS1 and the Science Collaboration, visit http://ps1sc.org/

  14. Accelerated evolution of the Lyα luminosity function at z ≳ 7 revealed by the Subaru ultra-deep survey for Lyα emitters at z = 7.3

    SciTech Connect

    Konno, Akira; Ouchi, Masami; Ono, Yoshiaki; Shibuya, Takatoshi; Naito, Yoshiaki; Momose, Rieko; Yuma, Suraphong; Shimasaku, Kazuhiro; Nakajima, Kimihiko; Furusawa, Hisanori; Iye, Masanori

    2014-12-10

    We present the ultra-deep Subaru narrowband imaging survey for Lyα emitters (LAEs) at z = 7.3 in the Subaru/XMM-Newton Deep Survey (SXDS) and Cosmic Evolution Survey (COSMOS) fields (∼0.5 deg{sup 2}) with a total integration time of 106 hr. Exploiting our new sharp bandwidth filter, NB101, installed on the Suprime-Cam, we have reached L(Lyα) = 2.4 × 10{sup 42} erg s{sup –1} (5σ) for z = 7.3 LAEs, about four times deeper than previous Subaru z ≳ 7 studies, which allows us to reliably investigate the evolution of the Lyα luminosity function (LF) for the first time down to the luminosity limit same as those of Subaru z = 3.1-6.6 LAE samples. Surprisingly, we only find three and four LAEs in the SXDS and COSMOS fields, respectively, while one expects a total of ∼65 LAEs by our survey in the case of no Lyα LF evolution from z = 6.6 to 7.3. We identify a decrease of the Lyα LF from z = 6.6 to 7.3 at the >90% confidence level from our z = 7.3 Lyα LF with the best-fit Schechter parameters of L{sub Lyα}{sup ∗}=2.7{sub −1.2}{sup +8.0}×10{sup 42} erg s{sup −1} and ϕ{sup ∗}=3.7{sub −3.3}{sup +17.6}×10{sup −4} Mpc{sup −3} for a fixed α = –1.5. Moreover, the evolution of the Lyα LF is clearly accelerated at z > 6.6 beyond the measurement uncertainties including cosmic variance. Because no such accelerated evolution of the UV-continuum LF or the cosmic star formation rate (SFR) is found at z ∼ 7, but suggested only at z > 8, this accelerated Lyα LF evolution is explained by physical mechanisms different from a pure SFR decrease but related to the Lyα production and escape in the process of cosmic reionization. Because a simple accelerating increase of intergalactic medium neutral hydrogen absorbing Lyα cannot be reconciled with Thomson scattering of optical depth measurements from WMAP and Planck, our findings may support new physical pictures suggested by recent theoretical studies, such as the existence of HI clumpy clouds within

  15. SEDS: The Spitzer Extended Deep Survey. Survey Design, Photometry, and Deep IRAC Source Counts

    NASA Technical Reports Server (NTRS)

    Ashby, M. L. N.; Willner, S. P.; Fazio, G. G.; Huang, J.-S.; Arendt, A.; Barmby, P.; Barro, G; Bell, E. F.; Bouwens, R.; Cattaneo, A.; Croton, D.; Dave, R.; Dunlop, J. S.; Egami, E.; Faber, S.; Finlator, K.; Grogin, N. A.; Guhathakurta, P.; Hernquist, L.; Hora, J. L.; Illingworth, G.; Kashlinsky, A; Koekmoer, A. M.; Koo, D. C.; Moseley, H.

    2013-01-01

    The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg(exp 2) to a depth of 26 AB mag (3sigma) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 micron. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 +/- 1.0 and 4.4 +/- 0.8 nW / square m/sr at 3.6 and 4.5 micron to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component.

  16. Ubercalibration of the Deep Lens Survey

    NASA Astrophysics Data System (ADS)

    Wittman, D.; Ryan, R.; Thorman, P.

    2012-04-01

    We describe the internal photometric calibration of the Deep Lens Survey, which consists of five widely separated fields observed by two different observatories. Adopting the global linear least-squares ('ubercal') approach developed for the Sloan Digital Sky Survey (SDSS), we derive flat-field corrections for all observing runs, which indicate that the original sky flats were non-uniform by up to 0.13 mag peak-to-valley in z band, and by up to half of that amount in BVR. We show that the application of these corrections reduces spatial non-uniformities in corrected exposures to the 0.01-0.02 mag level. We conclude with some lessons learned in applying ubercal to a survey structured very differently from SDSS, with isolated fields, multiple observatories and shift-and-stare rather than drift-scan imaging. Although the size of the error caused by using sky or dome flats is instrument and wavelength dependent, users of wide-field cameras should not assume that it is small. Pipeline developers should facilitate routine application of this procedure, and surveys should include it in their plans from the outset.

  17. Applying galactic archeology to massive galaxies using deep imaging surveys

    NASA Astrophysics Data System (ADS)

    Duc, Pierre-Alain

    2015-04-01

    Various programs aimed at exploring the still largely unknown low surface brightness Universe with deep imaging optical surveys have recently started. They open a new window for studies of galaxy evolution, pushing the technique of galactic archeology outside the Local Group (LG). The method, based on the detection and analysis of the diffuse light emitted by collisional debris or extended stellar halos (rather than on stellar counts as done for LG systems), faces however a number of technical difficulties, like the contamination of the images by reflection halos and Galactic cirrus. I review here the on-going efforts to address them and highlight the preliminary promising results obtained with a systematic survey with MegaCam on the CFHT of nearby massive early-type galaxies done as part of the ATLAS3D, NGVS and MATLAS collaborations.

  18. MOIRCS Deep Survey. I: DRG Number Counts

    NASA Astrophysics Data System (ADS)

    Kajisawa, Masaru; Konishi, Masahiro; Suzuki, Ryuji; Tokoku, Chihiro; Uchimoto, Yuka; Katsuno; Yoshikawa, Tomohiro; Akiyama, Masayuki; Ichikawa, Takashi; Ouchi, Masami; Omata, Koji; Tanaka, Ichi; Nishimura, Tetsuo; Yamada, Toru

    2006-12-01

    We used very deep near-infrared imaging data taken with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru Telescope to investigate the number counts of Distant Red Galaxies (DRGs). We observed a 4' × 7' field in the Great Observatories Origins Deep Survey-North (GOODS-N), and our data reached J=24.6 and K=23.2 (5σ, Vega magnitude). The surface density of DRGs selected by J - K > 2.3 is 2.35 ± 0.31 arcmin-2 at K < 22 and 3.54 ± 0.38 arcmin-2 at K < 23, respectively. These values are consistent with those in the GOODS-South and FIRES. Our deep and wide data suggest that the number counts of DRGs turn over at K ˜ 22, and the surface density of the faint DRGs with K > 22 is smaller than that expected from the number counts at the brighter magnitude. The result indicates that while there are many bright galaxies at 2 < z < 4 with the relatively old stellar population and/or heavy dust extinction, the number of faint galaxies with a similar red color is relatively small. Different behavior patterns of the number counts of the DRGs and bluer galaxies with 2 < zphot < 4 at K > 22 suggest that the mass-dependent color distribution, where most of the low-mass galaxies are blue, while more massive galaxies tend to have redder colors, had already been established at that epoch.

  19. An ALMA survey of submillimeter galaxies in the extended Chandra deep field south: The redshift distribution and evolution of submillimeter galaxies

    SciTech Connect

    Simpson, J. M.; Swinbank, A. M.; Smail, Ian; Alexander, D. M.; Danielson, A. L. R.; Thomson, A. P.; Brandt, W. N.; Bertoldi, F.; Karim, A.; De Breuck, C.; Chapman, S. C.; Coppin, K. E. K.; Da Cunha, E.; Hodge, J. A.; Schinnerer, E.; Dannerbauer, H.; Greve, T. R.; Ivison, R. J.; Knudsen, K. K.; Poggianti, B. M.; and others

    2014-06-20

    We present the first photometric redshift distribution for a large sample of 870 μm submillimeter galaxies (SMGs) with robust identifications based on observations with ALMA. In our analysis we consider 96 SMGs in the Extended Chandra Deep Field South, 77 of which have 4-19 band photometry. We model the SEDs for these 77 SMGs, deriving a median photometric redshift of z {sub phot} = 2.3 ± 0.1. The remaining 19 SMGs have insufficient photometry to derive photometric redshifts, but a stacking analysis of Herschel observations confirms they are not spurious. Assuming that these SMGs have an absolute H-band magnitude distribution comparable to that of a complete sample of z ∼ 1-2 SMGs, we demonstrate that they lie at slightly higher redshifts, raising the median redshift for SMGs to z {sub phot} = 2.5 ± 0.2. Critically we show that the proportion of galaxies undergoing an SMG-like phase at z ≥ 3 is at most 35% ± 5% of the total population. We derive a median stellar mass of M {sub *} = (8 ± 1) × 10{sup 10} M {sub ☉}, although there are systematic uncertainties of up to 5 × for individual sources. Assuming that the star formation activity in SMGs has a timescale of ∼100 Myr, we show that their descendants at z ∼ 0 would have a space density and M{sub H} distribution that are in good agreement with those of local ellipticals. In addition, the inferred mass-weighted ages of the local ellipticals broadly agree with the look-back times of the SMG events. Taken together, these results are consistent with a simple model that identifies SMGs as events that form most of the stars seen in the majority of luminous elliptical galaxies at the present day.

  20. The BMW Deep X-Ray Cluster Survey

    NASA Astrophysics Data System (ADS)

    Guzzo, Luigi; Moretti, Alberto; Campana, Sergio; Covino, Stefano; Dell'Antonio, Ian; Lazzati, Davide; Longhetti, Marcella; Molinari, Emilio; Panzera, Maria Rosa; Tagliaferri, Gianpiero

    We briely describe the main features and first results of the BMW survey of serendipitous X-ray clusters, based on the still unexploited ROSAT-HRI archival observations. The sky coverage, surface density and first deep CCD images of the candidates indicate that this sample can represent an excellent complement to the existing PSPC deep cluster surveys.

  1. The Gemini Deep Planet Survey - GDPS

    SciTech Connect

    Lafreniere, D; Doyon, R; Marois, C; Nadeau, D; Oppenheimer, B R; Roche, P F; Rigaut, F; Graham, J R; Jayawardhana, R; Johnstone, D; Kalas, P G; Macintosh, B; Racine, R

    2007-06-01

    We present the results of the Gemini Deep Planet Survey, a near-infrared adaptive optics search for giant planets and brown dwarfs around nearby young stars. The observations were obtained with the Altair adaptive optics system at the Gemini North telescope and angular differential imaging was used to suppress the speckle noise of the central star. Detection limits for the 85 stars observed are presented, along with a list of all faint point sources detected around them. Typically, the observations are sensitive to angular separations beyond 0.5-inch with 5{sigma} contrast sensitivities in magnitude difference at 1.6 {micro}m of 9.6 at 0.5-inch, 12.9 at 1-inch, 15 at 2-inch, and 16.6 at 5-inch. For the typical target of the survey, a 100 Myr old K0 star located 22 pc from the Sun, the observations are sensitive enough to detect planets more massive than 2 M{sub Jup} with a projected separation in the range 40-200 AU. Depending on the age, spectral type, and distance of the target stars, the minimum mass that could be detected with our observations can be {approx}1 M{sub Jup}. Second epoch observations of 48 stars with candidates (out of 54) have confirmed that all candidates are unrelated background stars. A detailed statistical analysis of the survey results, which provide upper limits on the fractions of stars with giant planet or low mass brown dwarf companions, is presented. Assuming a planet mass distribution dn/dm {proportional_to} m{sup -1.2} and a semi-major axis distribution dn/da {proportional_to} a{sup -1}, the upper limits on the fraction of stars with at least one planet of mass 0.5-13 M{sub Jup} are 0.29 for the range 10-25 AU, 0.13 for 25-50 AU, and 0.09 for 50-250 AU, with a 95% confidence level; this result is weakly dependent on the semi-major axis distribution power-law index. Without making any assumption on the mass and semi-major axis distributions, the fraction of stars with at least one brown dwarf companion having a semi-major axis in the

  2. Deep Surveys for Inner Oort Cloud Objects

    NASA Astrophysics Data System (ADS)

    Trujillo, Chadwick A.; Tholen, David J.; Sheppard, Scott S.

    2015-11-01

    We are undertaking two deep wide-field surveys to discover extremely distant solar system objects. While our target solar system population is the Inner Oort Cloud objects such as 2012 VP113 and Sedna, we are also sensitive to other populations with high perihelia such as the Scattered Kuiper Belt Objects and the highest perihelion Kuiper Belt Objects which have similar arguments of perihelion to the Inner Oort Cloud Objects. These unusual populations are thought to consist primarily of highly eccentric objects which spend most of their orbits hundreds or thousands of AU from the sun. Large aperture telescopes are needed to reach the faintness limits, red magnitudes of 23.5 to 25, required for detection of even the large members of the population. In addition, wide fields of view are also needed since the sky density of the detectable members of the populations approach 1 in 100 square degrees even with large telescopes.Our primary discovery instruments are the Dark Energy Camera (DECam) on the 4 meter Blanco Telescope at the Cerro Tololo Inter-American Observatory and Hyper Suprime-Cam (HSC) on Subaru Telescope at Maunakea. Each of these instruments has a tremendously wide field of view considering the size of the telescope they are mounted on. DECam has a field of view of about 3 square degrees and HSC has a field of view of about 1.75 square degrees. We will present our survey progress in terms of sky area covered and new objects discovered and highlight some of our more interesting findings.

  3. Impact Crater Size and Evolution: Expectations for Deep Impact

    NASA Technical Reports Server (NTRS)

    Schultz, P. H.; Anderson, J. L. B.; Heineck, J. T.

    2002-01-01

    Deep Impact will involve a unique cratering experiment designed to probe below the surface of a comet. Laboratory experiments provide critical data for crater scaling and evolution of the ejecta curtain. Additional information is contained in the original extended abstract.

  4. Optical galaxy clusters in the Deep Lens Survey

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Wittman, D.; Dawson, W.

    2014-04-01

    We present the first sample of 882 optically selected galaxy clusters in the Deep Lens Survey (DLS), selected with the Bayesian Cluster Finder. We create mock DLS data to assess completeness and purity rates, and find that both are at least 70 per cent within 0.1 ≤ z ≤ 1.2 for clusters with M200 ≥ 1.2 × 1014 M⊙. We verified the integrity of the sample by performing several comparisons with other optical, weak lensing, X-ray and spectroscopic surveys which overlap the DLS footprint: the estimated redshifts are consistent with the spectroscopic redshifts of known clusters (for z > 0.25 where saturation in the DLS is not an issue); our richness estimates in combination with a previously calibrated richness-mass relation yield individual cluster mass estimates consistent with available Smithsonian Hectospec Lensing Survey dynamical mass estimates; synthetic mass maps made from the optical mass estimates are correlated (>3σ significance) with the weak lensing mass maps; and the mass function thus derived is consistent with theoretical predictions for the cold dark matter scenario. With the verified sample, we investigated correlations between the brightest cluster galaxy (BCG) properties and the host cluster properties within a broader range in redshift (0.25 ≤ z ≤ 0.8) and mass (≥2.4 × 1014 M⊙) than in previous work. We find that the slope of the BCG magnitude-redshift relation throughout this redshift range is consistent with that found at lower redshifts. This result supports an extrapolation to higher redshift of passive evolution of the BCG within the hierarchical scenario.

  5. Origin and Evolution of Deep Brain Stimulation

    PubMed Central

    Sironi, Vittorio A.

    2011-01-01

    This paper briefly describes how the electrical stimulation, used since antiquity to modulate the nervous system, has been a fundamental tool of neurophysiologic investigation in the second half of the eighteenth century and was subsequently used by the early twentieth century, even for therapeutic purposes. In mid-twentieth century the advent of stereotactic procedures has allowed the drift from lesional to stimulating technique of deep nuclei of the brain for therapeutic purposes. In this way, deep brain stimulation (DBS) was born, that, over the last two decades, has led to positive results for the treatment of medically refractory Parkinson’s disease, essential tremor, and dystonia. In recent years, the indications for therapeutic use of DBS have been extended to epilepsy, Tourette’s syndrome, psychiatric diseases (depression, obsessive–compulsive disorder), some kinds of headache, eating disorders, and the minimally conscious state. The potentials of the DBS for therapeutic use are fascinating, but there are still many unresolved technical and ethical problems, concerning the identification of the targets for each disease, the selection of the patients and the evaluation of the results. PMID:21887135

  6. A very deep IRAS survey at the north ecliptic pole

    NASA Technical Reports Server (NTRS)

    Houck, J. R.; Hacking, P. B.; Condon, J. J.

    1987-01-01

    The data from approximately 20 hours observation of the 4- to 6-square degree field surrounding the north ecliptic pole have been combined to produce a very deep IR survey at the four IRAS bands. Scans from both pointed and survey observations were included in the data analysis. At 12 and 25 microns the deep survey is limited by detector noise and is approximately 50 times deeper than the IRAS Point Source Catalog (PSC). At 60 microns the problems of source confusion and Galactic cirrus combine to limit the deep survey to approximately 12 times deeper than the PSC. These problems are so severe at 100 microns that flux values are only given for locations corresponding to sources selected at 60 microns. In all, 47 sources were detected at 12 microns, 37 at 25 microns, and 99 at 60 microns. The data-analysis procedures and the significance of the 12- and 60-micron source-count results are discussed.

  7. The variable sky of deep synoptic surveys

    SciTech Connect

    Ridgway, Stephen T.; Matheson, Thomas; Mighell, Kenneth J.; Olsen, Knut A.; Howell, Steve B.

    2014-11-20

    The discovery of variable and transient sources is an essential product of synoptic surveys. The alert stream will require filtering for personalized criteria—a process managed by a functionality commonly described as a Broker. In order to understand quantitatively the magnitude of the alert generation and Broker tasks, we have undertaken an analysis of the most numerous types of variable targets in the sky—Galactic stars, quasi-stellar objects (QSOs), active galactic nuclei (AGNs), and asteroids. It is found that the Large Synoptic Survey Telescope (LSST) will be capable of discovering ∼10{sup 5} high latitude (|b| > 20°) variable stars per night at the beginning of the survey. (The corresponding number for |b| < 20° is orders of magnitude larger, but subject to caveats concerning extinction and crowding.) However, the number of new discoveries may well drop below 100 per night within less than one year. The same analysis applied to GAIA clarifies the complementarity of the GAIA and LSST surveys. Discovery of AGNs and QSOs are each predicted to begin at ∼3000 per night and decrease by 50 times over four years. Supernovae are expected at ∼1100 per night, and after several survey years will dominate the new variable discovery rate. LSST asteroid discoveries will start at >10{sup 5} per night, and if orbital determination has a 50% success rate per epoch, they will drop below 1000 per night within two years.

  8. A warm Spitzer survey of the LSST/DES 'Deep drilling' fields

    NASA Astrophysics Data System (ADS)

    Lacy, Mark; Farrah, Duncan; Brandt, Niel; Sako, Masao; Richards, Gordon; Norris, Ray; Ridgway, Susan; Afonso, Jose; Brunner, Robert; Clements, Dave; Cooray, Asantha; Covone, Giovanni; D'Andrea, Chris; Dickinson, Mark; Ferguson, Harry; Frieman, Joshua; Gupta, Ravi; Hatziminaoglou, Evanthia; Jarvis, Matt; Kimball, Amy; Lubin, Lori; Mao, Minnie; Marchetti, Lucia; Mauduit, Jean-Christophe; Mei, Simona; Newman, Jeffrey; Nichol, Robert; Oliver, Seb; Perez-Fournon, Ismael; Pierre, Marguerite; Rottgering, Huub; Seymour, Nick; Smail, Ian; Surace, Jason; Thorman, Paul; Vaccari, Mattia; Verma, Aprajita; Wilson, Gillian; Wood-Vasey, Michael; Cane, Rachel; Wechsler, Risa; Martini, Paul; Evrard, August; McMahon, Richard; Borne, Kirk; Capozzi, Diego; Huang, Jiashang; Lagos, Claudia; Lidman, Chris; Maraston, Claudia; Pforr, Janine; Sajina, Anna; Somerville, Rachel; Strauss, Michael; Jones, Kristen; Barkhouse, Wayne; Cooper, Michael; Ballantyne, David; Jagannathan, Preshanth; Murphy, Eric; Pradoni, Isabella; Suntzeff, Nicholas; Covarrubias, Ricardo; Spitler, Lee

    2014-12-01

    We propose a warm Spitzer survey to microJy depth of the four predefined Deep Drilling Fields (DDFs) for the Large Synoptic Survey Telescope (LSST) (three of which are also deep drilling fields for the Dark Energy Survey (DES)). Imaging these fields with warm Spitzer is a key component of the overall success of these projects, that address the 'Physics of the Universe' theme of the Astro2010 decadal survey. With deep, accurate, near-infrared photometry from Spitzer in the DDFs, we will generate photometric redshift distributions to apply to the surveys as a whole. The DDFs are also the areas where the supernova searches of DES and LSST are concentrated, and deep Spitzer data is essential to obtain photometric redshifts, stellar masses and constraints on ages and metallicities for the >10000 supernova host galaxies these surveys will find. This 'DEEPDRILL' survey will also address the 'Cosmic Dawn' goal of Astro2010 through being deep enough to find all the >10^11 solar mass galaxies within the survey area out to z~6. DEEPDRILL will complete the final 24.4 square degrees of imaging in the DDFs, which, when added to the 14 square degrees already imaged to this depth, will map a volume of 1-Gpc^3 at z>2. It will find ~100 > 10^11 solar mass galaxies at z~5 and ~40 protoclusters at z>2, providing targets for JWST that can be found in no other way. The Spitzer data, in conjunction with the multiwavelength surveys in these fields, ranging from X-ray through far-infrared and cm-radio, will comprise a unique legacy dataset for studies of galaxy evolution.

  9. CANDELS: THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY

    SciTech Connect

    Grogin, Norman A.; Ferguson, Henry C.; Koekemoer, Anton M.; Brown, Thomas M.; Casertano, Stefano; Kocevski, Dale D.; Faber, S. M.; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Cassata, Paolo; Castellano, Marco; Challis, Peter; Chary, Ranga-Ram; and others

    2011-12-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8-1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the mid-ultraviolet to the near-infrared, and will find and measure Type Ia supernovae at z > 1.5 to test their accuracy as standardizable candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10{sup 9} M{sub Sun} to z Almost-Equal-To 2, reaching the knee of the ultraviolet luminosity function of galaxies to z Almost-Equal-To 8. The survey covers approximately 800 arcmin{sup 2} and is divided into two parts. The CANDELS/Deep survey (5{sigma} point-source limit H = 27.7 mag) covers {approx}125 arcmin{sup 2} within Great Observatories Origins Deep Survey (GOODS)-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (Extended Groth Strip, COSMOS, and Ultra-deep Survey) and covers the full area to a 5{sigma} point-source limit of H {approx}> 27.0 mag. Together with the Hubble Ultra Deep Fields, the strategy creates a three-tiered 'wedding-cake' approach that has proven efficient for extragalactic surveys. Data from the survey are nonproprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design. The Hubble data processing and products are described in a companion paper.

  10. The UKIDSS Deep eXtra-Galactic Survey

    NASA Astrophysics Data System (ADS)

    Swinbank, A. M.

    The UKIDSS Deep eXtra-Galactic (DXS) will image an area of 35 sq.deg. at high Galactic latitudes in the J and K-band filters to a depth K = 21.0 (with 5 sq.deg. also imaged in H-band). When completed in 2012, the DXS will have used 118 nights to survey 4 of the best-studied extra-galactic fields: XMM-LSS, the Lockman Hole, SSA22 and ELAIS-N1. The principal goals of the DXS are to identify and measure the abundance of galaxy clusters at 0.8 < z < 1.5; to measure galaxy clustering in well defined samples at z > 1 (and hence measure the evolution of bias, a key test of hierarchical models); and to provide a multi-wavelength census of the luminosity density in star formation and AGN. Here, we describe some of the recent science highlights. Specifically, the discovery of a supercluster at z = 0.9 which spans >30 Mpc and has properties similar to local super-clusters (such as Hercules) and some of the first wide-field (˜3-sq.deg.) clustering measurements in EROs and DRGs.

  11. The Deep Ecliptic Survey -- A Status Report

    NASA Astrophysics Data System (ADS)

    Millis, R. L.; Buie, M. W.; Wasserman, L. H.; Elliot, J. L.; Kern, S. D.; Wagner, R. M.; Chiang, E.; Trilling, D.

    2001-11-01

    We are conducting a survey of the Kuiper Belt using the 4-m telescopes and MOSAIC cameras at KPNO and CTIO. This program has resulted in the discovery of well over 200 KBOs and Centaurs including 28978 = 2001 KX76, the intrinsically brightest KBO (Millis, et al., IAUC 7657, 2001); 1998 WW31, subsequently found to be a binary (Veillet, IAUC 7610, 2001); 2000 CR105, a scattered disk object with a perihelion distance of at least 44 AU (Gladman, et al., Science News 159, 213, 2001); and 2000 OO67, a scattered disk object with an aphelion distance in excess of 1000 AU (Marsden, MPEC P43, 2001). Beginning with semester 2001B, this program has been granted survey status at the national observatories and will receive 20 nights per year for the next 3 years. In this paper, we will summarize the results to date from the survey, discuss plans for dissemination of the survey data and results, highlight certain problems we are facing, and propose ways in which the community can cooperate to increase the overall productivity of Kuiper Belt searches. This work is supported at Lowell Observatory by NASA Grants NAG5-8990 and NAG5-11058 and at MIT by NASA Grant NAG5-10444.

  12. Origin and Evolution of Deep Plasmaspheric Notches

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Adrian, M. L.; Liemohn, M. W.

    2005-01-01

    Deep plasmaspheric notches can extend over more than 2 R(sub E) in radial distance and 3 hours MLT in the magnetic equatorial plane, as observed by the extreme ultraviolet (EUV) imager on the IMAGE mission. They are among the largest evacuated features in the exterior plasmaspheric boundary. They can last for days and exhibit a variety of shapes. It appears that weak convection and limited erosion precedes notch formation at the westward, near-Earth edge of the convection plume. Eighteen clear notch events were found and analyzed in 2000. Among these events, notches were found to drift as slowly as 44% of corotation. In only one case was a notch found to drift at the corotation rate within measurement error. On average, these notches drift at about 21.5 h d(sup -1) or 90% of the corotational rate. Notches sometimes exhibit an interior structure that appears as an extended prominence of dense plasma, which forms a W- or M-like feature in IMAGE/EUV images, depending on viewing perspective. Initial modeling suggests that notches and notch prominences may be caused in part by intense small-scale potential structures that result from the localized injection of ring current plasma. Plasma filling rates during recovery are examined in three L shell ranges from L = 2 to L = 3.5 with rates ranging from 5 to 140 cm(sup -3) d(sup -1). Plasma loss during a minor substorm is found to extend to surprisingly low L shell with rates ranging from 100 to 130 cm(sup -3) d(sup -1) across the L shells examined.

  13. DEEP 21 cm H I OBSERVATIONS AT z {approx} 0.1: THE PRECURSOR TO THE ARECIBO ULTRA DEEP SURVEY

    SciTech Connect

    Freudling, Wolfram; Zwaan, Martin; Staveley-Smith, Lister; Meyer, Martin; Catinella, Barbara; Minchin, Robert; Calabretta, Mark; Momjian, Emmanuel; O'Neil, Karen

    2011-01-20

    The 'ALFA Ultra Deep Survey' (AUDS) is an ongoing 21 cm spectral survey with the Arecibo 305 m telescope. AUDS will be the most sensitive blind survey undertaken with Arecibo's 300 MHz Mock spectrometer. The survey searches for 21 cm H I line emission at redshifts between 0 and 0.16. The main goals of the survey are to investigate the H I content and probe the evolution of H I gas within that redshift region. In this paper, we report on a set of precursor observations with a total integration time of 53 hr. The survey detected a total of eighteen 21 cm emission lines at redshifts between 0.07 and 0.15 in a region centered around {alpha}{sub 2000} {approx} 0{sup h}, {delta} {approx} 15{sup 0}42'. The rate of detection is consistent with the one expected from the local H I mass function. The derived relative H I density at the median redshift of the survey is {rho}{sub H{sub I}}[z = 0.125] = (1.0 {+-} 0.3){rho}{sub 0}, where {rho}{sub 0} is the H I density at zero redshift.

  14. A Deep Optical Survey of the Ecliptic

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    1997-01-01

    This was an observing-intensive investigation into the newly discovered regions of the solar system beyond Neptune. The research was focussed on the use of unique imaging facilities on telescopes atop Mauna Kea, Hawaii, although other observatories (in Arizona and Chile) were also occasionally used. We secured about 20 nights of telescope time per year for our 'Medium Depth Wide Area' survey (JLC96). In this, we covered 5 sq. deg. of sky to apparent red magnitude 24.2. We used a high quantum efficiency Tektronix 2048x2048 CCD for all observations in this program. We secured observing time at the UH 2.2 meter for testing the suitability of a much larger array CCD camera for survey work (an 8192x8192 pixel device). We obtained observing runs at the twin Schmidt telescopes of Kitt Peak National Observatory and Cerro-Tololo InterAmerican Observatory in order to assess the number of bright Kuiper Belt objects, Centaurs and gas giant Trojans.

  15. Initial results from a ROSAT deep survey in Lynx

    NASA Technical Reports Server (NTRS)

    Anderson, S. F.; Windhorst, R. A.; Maccacaro, T.; Burstein, D.; Franklin, B. E.; Griffiths, R. E.; Koo, D. C.; Mathis, D. F.; Morgan, W. A.; Neuschaefer, L. W.

    1992-01-01

    Preliminary results from a deep (70 ksec) Rosat survey of the high galactic latitude selected area Lynx.3A are presented. Lynx.3A sensitivity was previously studied in both the optical radio, with deep Westerbork surveys and deep multicolor Charge Couple Device (CCD) images form the Palomar 200 inch Four-Shooter. About 70 x-ray sources were detected within the central 40 foot diameter region of the Position Sensitive Proportional Counter (PSPC), observed surface densities of approximately 200 x-ray sources/sq deg are suggested, and these x-ray sources alone account for approximately 30 percent of the cosmic x-ray background (0.9 to 2.2 keV). An initial look at the observed x-ray logN - logS curve is presented, but a detailed assessment requires further study. The 4 sigma limit of about 7 times 10 to the minus 15th power erg/s.sq cm (0.5 to 2.0 keV) is considerably deeper then the Einstein deep surveys, and of comparable sensitivity to the deepest current Rosat surveys. Cross correlation with our Four Shooter optical catalogs yields at least one likely optical candidate for nearly all of the Rosat x-ray sources; a number of the likely optical identifications have colors of quasi-stellar objects (and stellar PSF), but in other cases galaxies/groups are also viable candidates.

  16. The Secret Lives Of Galaxies Unveiled In Deep Survey

    NASA Astrophysics Data System (ADS)

    2003-06-01

    Two of NASA's Great Observatories, bolstered by the largest ground-based telescopes around the world, are beginning to harvest new clues to the origin and evolution of galaxies. It's a bit like finding a family scrapbook containing snapshots that capture the lives of family members from infancy through adolescence to adulthood. "This is the first time the cosmic tale of how galaxies build themselves has been traced reliably to such early times in the universe's life," said Mauro Giavalisco, head of the Hubble Space Telescope (HST) portion of the survey, and research astronomer at the Space Telescope Science Institute (STScI) in Baltimore. The HST has joined forces with the Chandra X-ray Observatory to survey a relatively broad swath of sky encompassing tens of thousands of galaxies stretching far back into time. The Space Infrared Telescope Facility (SIRTF), scheduled for launch in August, will soon join this unprecedented survey. Called the Great Observatories Origins Deep Survey (GOODS), astronomers are studying galaxy formation and evolution over a wide range of distances and ages. The project is tracing the assembly history of galaxies, the evolution of their stellar populations, and the gusher of energy from star formation and active nuclei powered by immense black holes. HST astronomers report the sizes of galaxies clearly increase continuously from the time the universe was about 1 billion years old to an age of 6 billion years. This is approximately half the current age of the universe, 13.7 billion years. GOODS astronomers also find the star birth rate rose mildly, by about a factor of three, between the time the universe was about one billion years old and 1.5 billion years old, and remained high until about 7 billion years ago, when it quickly dropped to one-tenth the earlier "baby boomer" rate. This is further evidence major galaxy building trailed off when the universe was about half its current age. GOODS Chandra Deep Fields South Chandra Deep Field

  17. The Secret Lives Of Galaxies Unveiled In Deep Survey

    NASA Astrophysics Data System (ADS)

    2003-06-01

    Two of NASA's Great Observatories, bolstered by the largest ground-based telescopes around the world, are beginning to harvest new clues to the origin and evolution of galaxies. It's a bit like finding a family scrapbook containing snapshots that capture the lives of family members from infancy through adolescence to adulthood. "This is the first time the cosmic tale of how galaxies build themselves has been traced reliably to such early times in the universe's life," said Mauro Giavalisco, head of the Hubble Space Telescope (HST) portion of the survey, and research astronomer at the Space Telescope Science Institute (STScI) in Baltimore. The HST has joined forces with the Chandra X-ray Observatory to survey a relatively broad swath of sky encompassing tens of thousands of galaxies stretching far back into time. The Space Infrared Telescope Facility (SIRTF), scheduled for launch in August, will soon join this unprecedented survey. Called the Great Observatories Origins Deep Survey (GOODS), astronomers are studying galaxy formation and evolution over a wide range of distances and ages. The project is tracing the assembly history of galaxies, the evolution of their stellar populations, and the gusher of energy from star formation and active nuclei powered by immense black holes. HST astronomers report the sizes of galaxies clearly increase continuously from the time the universe was about 1 billion years old to an age of 6 billion years. This is approximately half the current age of the universe, 13.7 billion years. GOODS astronomers also find the star birth rate rose mildly, by about a factor of three, between the time the universe was about one billion years old and 1.5 billion years old, and remained high until about 7 billion years ago, when it quickly dropped to one-tenth the earlier "baby boomer" rate. This is further evidence major galaxy building trailed off when the universe was about half its current age. GOODS Chandra Deep Fields South Chandra Deep Field

  18. Prospects for the Study of Evolution in the Deep Biosphere

    PubMed Central

    Biddle, Jennifer F.; Sylvan, Jason B.; Brazelton, William J.; Tully, Benjamin J.; Edwards, Katrina J.; Moyer, Craig L.; Heidelberg, John F.; Nelson, William C.

    2012-01-01

    Since the days of Darwin, scientists have used the framework of the theory of evolution to explore the interconnectedness of life on Earth and adaptation of organisms to the ever-changing environment. The advent of molecular biology has advanced and accelerated the study of evolution by allowing direct examination of the genetic material that ultimately determines the phenotypes upon which selection acts. The study of evolution has been furthered through examination of microbial evolution, with large population numbers, short generation times, and easily extractable DNA. Such work has spawned the study of microbial biogeography, with the realization that concepts developed in population genetics may be applicable to microbial genomes (Martiny et al., 2006; Manhes and Velicer, 2011). Microbial biogeography and adaptation has been examined in many different environments. Here we argue that the deep biosphere is a unique environment for the study of evolution and list specific factors that can be considered and where the studies may be performed. This publication is the result of the NSF-funded Center for Dark Energy Biosphere Investigations (C-DEBI) theme team on Evolution (www.darkenergybiosphere.org). PMID:22319515

  19. Cosmic Shear Tomography from the Deep Lens Survey

    NASA Astrophysics Data System (ADS)

    Jee, Myungkook J.; Tyson, J. Anthony; Hilbert, Stefan; Schneider, Michael; Schmidt, Samuel; Wittman, David M.

    2016-01-01

    The Deep Lens Survey (DLS) is designed as a pre-cursor Large Synoptic Survey Telescope (LSST) survey with an emphasis on depth. Using five tomographic redshift bins, we study their auto- and cross-correlations to constrain cosmological parameters. Both instrumental and astrophysical systematics are carefully addressed with the state-of-the-art techniques. We find that the cosmological leverage of the DLS is among the highest among existing >10 sq. deg cosmic shear surveys. Combining the DLS tomography with the 9-year results of the Wilkinson Microwave Anisotropy Probe (WMAP9) reduces the uncertainties of the WMAP9-only constraints by ~50%. Our constraints are fully consistent with the final Planck results and also the predictions of a LCDM universe.

  20. Deep near-infrared survey of the Southern Sky (DENIS)

    NASA Technical Reports Server (NTRS)

    Deul, E.

    1992-01-01

    DENIS (Deep Near-Infrared Survey of the Southern Sky) will be the first complete census of astronomical sources in the near-infrared spectral range. The challenges of this novel survey are both scientific and technical. Phenomena radiating in the near-infrared range from brown dwarfs to galaxies in the early stages of cosmological evolution, the scientific exploitation of data relevant over such a wide range requires pooling expertise from several of the leading European astronomical centers. The technical challenges of a project which will provide an order of magnitude more sources than given by the IRAS space mission, and which will involve advanced data-handling and image-processing techniques, likewise require pooling of hardware and software resources, as well as of human expertise. The DENIS project team is composed of some 40 scientists, computer specialists, and engineers located in 5 European Community countries (France, Germany, Italy, The Netherlands, and Spain), with important contributions from specialists in Australia, Brazil, Chile, and Hungary. DENIS will survey the entire southern sky in 3 colors, namely in the I band at a wavelength of 0.8 micron, in the 1.25 micron J band, and in the 2.15 micron K' band. The sensitivity limits will be 18th magnitude in the I band, 16th in the J band, and 14.5th in the K' band. The angular resolution achieved will be 1 arcsecond in the I band, and 3.0 arcseconds in the J and K' bands. The European Southern Observatory 1 m telescope on La Silla will be dedicated to survey use during operations expected to last four years, commencing in late 1993. DENIS aims to provide the astronomical community with complete digitized infrared images of the full southern sky and a catalogue of extracted objects, both of the best quality and in readily accessible form. This will be achieved through dedicated software packages and specialized catalogues, and with assistance from the Leiden and Paris Data Analysis Centers. The data

  1. The VLA Survey of Chandra Deep Field South. V. Evolution and Luminosity Functions of Sub-millijansky Radio Sources and the Issue of Radio Emission in Radio-quiet Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Padovani, P.; Miller, N.; Kellermann, K. I.; Mainieri, V.; Rosati, P.; Tozzi, P.

    2011-10-01

    We present the evolutionary properties and luminosity functions of the radio sources belonging to the Chandra Deep Field South Very Large Array survey, which reaches a flux density limit at 1.4 GHz of 43 μJy at the field center and redshift ~5 and which includes the first radio-selected complete sample of radio-quiet active galactic nuclei (AGNs). We use a new, comprehensive classification scheme based on radio, far- and near-IR, optical, and X-ray data to disentangle star-forming galaxies (SFGs) from AGNs and radio-quiet from radio-loud AGNs. We confirm our previous result that SFGs become dominant only below 0.1 mJy. The sub-millijansky radio sky turns out to be a complex mix of SFGs and radio-quiet AGNs evolving at a similar, strong rate; non-evolving low-luminosity radio galaxies; and declining radio powerful (P >~ 3 × 1024 W Hz-1) AGNs. Our results suggest that radio emission from radio-quiet AGNs is closely related to star formation. The detection of compact, high brightness temperature cores in several nearby radio-quiet AGNs can be explained by the coexistence of two components, one non-evolving and AGN related and one evolving and star formation related. Radio-quiet AGNs are an important class of sub-millijansky sources, accounting for ~30% of the sample and ~60% of all AGNs, and outnumbering radio-loud AGNs at <~ 0.1 mJy. This implies that future, large area sub-millijansky surveys, given the appropriate ancillary multiwavelength data, have the potential of being able to assemble vast samples of radio-quiet AGNs, bypassing the problems of obscuration that plague the optical and soft X-ray bands.

  2. THE VLA SURVEY OF CHANDRA DEEP FIELD SOUTH. V. EVOLUTION AND LUMINOSITY FUNCTIONS OF SUB-MILLIJANSKY RADIO SOURCES AND THE ISSUE OF RADIO EMISSION IN RADIO-QUIET ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Padovani, P.; Mainieri, V.; Rosati, P.; Miller, N.; Kellermann, K. I.; Tozzi, P.

    2011-10-10

    We present the evolutionary properties and luminosity functions of the radio sources belonging to the Chandra Deep Field South Very Large Array survey, which reaches a flux density limit at 1.4 GHz of 43 {mu}Jy at the field center and redshift {approx}5 and which includes the first radio-selected complete sample of radio-quiet active galactic nuclei (AGNs). We use a new, comprehensive classification scheme based on radio, far- and near-IR, optical, and X-ray data to disentangle star-forming galaxies (SFGs) from AGNs and radio-quiet from radio-loud AGNs. We confirm our previous result that SFGs become dominant only below 0.1 mJy. The sub-millijansky radio sky turns out to be a complex mix of SFGs and radio-quiet AGNs evolving at a similar, strong rate; non-evolving low-luminosity radio galaxies; and declining radio powerful (P {approx}> 3 x 10{sup 24} W Hz{sup -1}) AGNs. Our results suggest that radio emission from radio-quiet AGNs is closely related to star formation. The detection of compact, high brightness temperature cores in several nearby radio-quiet AGNs can be explained by the coexistence of two components, one non-evolving and AGN related and one evolving and star formation related. Radio-quiet AGNs are an important class of sub-millijansky sources, accounting for {approx}30% of the sample and {approx}60% of all AGNs, and outnumbering radio-loud AGNs at {approx}< 0.1 mJy. This implies that future, large area sub-millijansky surveys, given the appropriate ancillary multiwavelength data, have the potential of being able to assemble vast samples of radio-quiet AGNs, bypassing the problems of obscuration that plague the optical and soft X-ray bands.

  3. The Spitzer Deep, Wide-Field Survey (SDWFS)

    NASA Astrophysics Data System (ADS)

    Ashby, Matthew; Stern, D.; Brodwin, M.; Griffith, R.; Eisenhardt, P.; Kozlowski, S.; Kochanek, C. S.; Bock, J.; Borys, C.; Brand, K.; Brown, M. J. I.; Cool, R.; Cooray, A.; Croft, S.; Dey, A.; Eisenstein, D.; Gonzalez, A.; Gorjian, V.; Grogin, N.; Ivison, R.; Jacob, J.; Jannuzi, B.; Mainzer, A.; Moustakas, L.; Rottgering, H.; Seymour, N.; Smith, H.; Stanford, A.; Stauffer, J. R.; Sullivan, I.; van Breugel, W.; Wright, E. L.; Willner, S. P.

    2009-05-01

    The Spitzer Deep, Wide-Field Survey (SDWFS) is four-epoch infrared survey of ten square degrees in the Bootes field of the NOAO Deep Wide-Field Survey using the IRAC instrument on the Spitzer Space Telescope. The four epochs, which span the interval from 2003 to 2008, make it possible to identify nearby, high-proper-motion targets, as well as infrared-variable objects. SDWFS is a Spitzer Cycle 4 Legacy program (PID 40839). The SDWFS catalogs are publicly available, and contain roughly 7e5, 5e5, 1e5, and 1e5 distinct sources brighter than the 5-sigma survey limits of 19.8, 18.8, 16.5, and 15.8 Vega magnitudes at 3.6, 4.5, 5.8, and 8.0 microns, respectively. In this contribution we describe the SDWFS survey and some initial findings. This work was supported by NASA grant number 1314516, administered by JPL.

  4. Evolution of the large Deep Space Network antennas

    NASA Astrophysics Data System (ADS)

    Imbriale, William A.

    1991-12-01

    The evolution of the largest antenna of the US NASA Deep Space Network (DSN) is described. The design, performance analysis, and measurement techniques, beginning with its initial 64-m operation at S-band (2295 MHz) in 1966 and continuing through the present ka-band (32-GHz) operation at 70 m, is described. Although their diameters and mountings differ, these parabolic antennas all employ a Cassegrainian feed system, and each antenna dish surface is constructed of precision-shaped perforated-aluminum panels that are secured to an open steel framework

  5. The Evolution of Deep Space Navigation: 1989-1999

    NASA Technical Reports Server (NTRS)

    Wood, Lincoln J.

    2008-01-01

    The exploration of the planets of the solar system using robotic vehicles has been underway since the early 1960s. During this time the navigational capabilities employed have increased greatly in accuracy, as required by the scientific objectives of the missions and as enabled by improvements in technology. This paper is the second in a chronological sequence dealing with the evolution of deep space navigation. The time interval covered extends from the 1989 launch of the Magellan spacecraft to Venus through a multiplicity of planetary exploration activities in 1999. The paper focuses on the observational techniques that have been used to obtain navigational information, propellant-efficient means for modifying spacecraft trajectories, and the computational methods that have been employed, tracing their evolution through a dozen planetary missions.

  6. THE GALAXY OPTICAL LUMINOSITY FUNCTION FROM THE AGN AND GALAXY EVOLUTION SURVEY

    SciTech Connect

    Cool, Richard J.; Eisenstein, Daniel J.; Kochanek, Christopher S.; Brown, Michael J. I.; Caldwell, Nelson; Forman, William R.; Hickox, Ryan C.; Jones, Christine; Murray, Stephen S.; Dey, Arjun; Jannuzi, Buell T.; Moustakas, John

    2012-03-20

    We present the galaxy optical luminosity function for the redshift range 0.05 < z < 0.75 from the AGN and Galaxy Evolution Survey, a spectroscopic survey of 7.6 deg{sup 2} in the Booetes field of the NOAO Deep Wide-Field Survey. Our statistical sample is composed of 12,473 galaxies with known redshifts down to I = 20.4 (AB). Our results at low redshift are consistent with those from Sloan Digital Sky Survey; at higher redshift, we find strong evidence for evolution in the luminosity function, including differential evolution between blue and red galaxies. We find that the luminosity density evolves as (1 + z){sup (0.54{+-}0.64)} for red galaxies and (1 + z){sup (1.64{+-}0.39)} for blue galaxies.

  7. Microbial Evolution at High Pressure: Deep Sea and Laboratory Studies

    NASA Astrophysics Data System (ADS)

    Bartlett, D. H.

    2011-12-01

    Elevated hydrostatic pressures are present in deep-sea and deep-Earth environments where this physical parameter has influenced the evolution and characteristics of life. Piezophilic (high-pressure-adapted) microbes have been isolated from diverse deep-sea settings, and would appear likely to occur in deep-subsurface habitats as well. In order to discern the factors enabling life at high pressure my research group has explored these adaptations at various levels, most recently including molecular analyses of deep-sea trench communities, and through the selective evolution of the model microbe Escherichia coli in the laboratory to progressively higher pressures. Much of the field work has focused on the microbes present in the deeper portions of the Puerto Rico Trench (PRT)and in the Peru-Chile Trench (PCT), from 6-8.5 km below the sea surface (~60-85 megapascals pressure). Culture-independent phylogenetic data on the Bacteria and Archaea present on particles or free-living, along with data on the microeukarya present was complemented with genomic analyses and the isolation and characterization of microbes in culture. Metagenomic analyses of the PRT revealed increased genome sizes and an overrepresentation at depth of sulfatases for the breakdown of sulfated polysaccharides and specific categories of transporters, including those associated with the transport of diverse cations or carboxylate ions, or associated with heavy metal resistance. Single-cell genomic studies revealed several linneages which recruited to the PRT metagenome far better than existing marine microbial genome sequences. analyses. Novel high pressure culture approaches have yielded new piezophiles including species preferring very low nutrient levels, those living off of hydrocarbons, and those adapted to various electron donor/electron acceptor combinations. In order to more specifically focus on functions enabling life at increased pressure selective evolution experiments were performed with

  8. A very deep IRAS survey. III - VLA observations

    NASA Astrophysics Data System (ADS)

    Hacking, Perry; Beichman, C. A.; Condon, J. J.; Houck, J. R.

    1989-04-01

    The 60-micron fluxes and positions of sources (primarily starburst galaxies) found in a deep IRAS survey by Hacking and Houck (1987) are compared with 1.49 HGz maps made by the Very Large Array. The radio results are consistent with radio measurements of brighter IRAS galaxies and provide evidence that infrared cirrus does not contaminate the 60-micron sample. The flux-independent ratio of infrared to radio flux densities implies that the 1.4 GHz luminosity function for spiral galaxies is evolving at less than (1 + z) to the power of 4 relative to the 60-micron luminosity function.

  9. Metabolic Evolution of a Deep-Branching Hyperthermophilic Chemoautotrophic Bacterium

    PubMed Central

    Braakman, Rogier; Smith, Eric

    2014-01-01

    Aquifex aeolicus is a deep-branching hyperthermophilic chemoautotrophic bacterium restricted to hydrothermal vents and hot springs. These characteristics make it an excellent model system for studying the early evolution of metabolism. Here we present the whole-genome metabolic network of this organism and examine in detail the driving forces that have shaped it. We make extensive use of phylometabolic analysis, a method we recently introduced that generates trees of metabolic phenotypes by integrating phylogenetic and metabolic constraints. We reconstruct the evolution of a range of metabolic sub-systems, including the reductive citric acid (rTCA) cycle, as well as the biosynthesis and functional roles of several amino acids and cofactors. We show that A. aeolicus uses the reconstructed ancestral pathways within many of these sub-systems, and highlight how the evolutionary interconnections between sub-systems facilitated several key innovations. Our analyses further highlight three general classes of driving forces in metabolic evolution. One is the duplication and divergence of genes for enzymes as these progress from lower to higher substrate specificity, improving the kinetics of certain sub-systems. A second is the kinetic optimization of established pathways through fusion of enzymes, or their organization into larger complexes. The third is the minimization of the ATP unit cost to synthesize biomass, improving thermodynamic efficiency. Quantifying the distribution of these classes of innovations across metabolic sub-systems and across the tree of life will allow us to assess how a tradeoff between maximizing growth rate and growth efficiency has shaped the long-term metabolic evolution of the biosphere. PMID:24516572

  10. Metabolic evolution of a deep-branching hyperthermophilic chemoautotrophic bacterium.

    PubMed

    Braakman, Rogier; Smith, Eric

    2014-01-01

    Aquifex aeolicus is a deep-branching hyperthermophilic chemoautotrophic bacterium restricted to hydrothermal vents and hot springs. These characteristics make it an excellent model system for studying the early evolution of metabolism. Here we present the whole-genome metabolic network of this organism and examine in detail the driving forces that have shaped it. We make extensive use of phylometabolic analysis, a method we recently introduced that generates trees of metabolic phenotypes by integrating phylogenetic and metabolic constraints. We reconstruct the evolution of a range of metabolic sub-systems, including the reductive citric acid (rTCA) cycle, as well as the biosynthesis and functional roles of several amino acids and cofactors. We show that A. aeolicus uses the reconstructed ancestral pathways within many of these sub-systems, and highlight how the evolutionary interconnections between sub-systems facilitated several key innovations. Our analyses further highlight three general classes of driving forces in metabolic evolution. One is the duplication and divergence of genes for enzymes as these progress from lower to higher substrate specificity, improving the kinetics of certain sub-systems. A second is the kinetic optimization of established pathways through fusion of enzymes, or their organization into larger complexes. The third is the minimization of the ATP unit cost to synthesize biomass, improving thermodynamic efficiency. Quantifying the distribution of these classes of innovations across metabolic sub-systems and across the tree of life will allow us to assess how a tradeoff between maximizing growth rate and growth efficiency has shaped the long-term metabolic evolution of the biosphere. PMID:24516572

  11. Weak lensing survey of galaxy clusters in the CFHTLS Deep

    NASA Astrophysics Data System (ADS)

    Gavazzi, R.; Soucail, G.

    2007-02-01

    Aims: We present a weak lensing search of galaxy clusters in the 4 deg2 of the CFHT Legacy Survey Deep. This work aims at building a mass-selected sample of clusters with well controlled selection effects. This present survey is a preliminary step toward a full implementation in the forthcoming 170 deg2 of the CFHTLS Wide survey. Methods: We use the deep i' band images observed under subarcsecond seeing conditions to perform weak lensing mass reconstructions and to identify high convergence peaks. Thanks to the availability of deep u^*g'r'i'z' exposures, sources are selected from their photometric redshifts in the weak lensing analysis. We also use lensing tomography to derive an estimate of the lens redshift. After considering the raw statistics of peaks we check whether they can be associated to a clear optical counterpart or to published X-ray selected clusters. Results: Among the 14 peaks found above a signal-to-noise detection threshold ν=3.5, nine are secure detections with estimated redshift 0.1⪉ z_l⪉0.7 and a velocity dispersion 450⪉σ_v⪉ 700 {km s}-1. This low mass range is accessible thanks to the high density of background sources. Considering the intersection between the shear-selected clusters and XMM-LSS X-ray clusters in the D1 field, we observe that the ICM gas in these low-mass clusters (T_X˜1{-}2 keV) is not hotter than the temperature inferred from shear, this trend being different for published massive clusters. A more extended weak lensing survey, with higher statistics of mass structures will be a promising way to bypass several of the problems related to standard detection methods based on the complex physics of baryons. Based 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 Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of

  12. Deep phylogeny and evolution of sponges (phylum Porifera).

    PubMed

    Wörheide, G; Dohrmann, M; Erpenbeck, D; Larroux, C; Maldonado, M; Voigt, O; Borchiellini, C; Lavrov, D V

    2012-01-01

    Sponges (phylum Porifera) are a diverse taxon of benthic aquatic animals of great ecological, commercial, and biopharmaceutical importance. They are arguably the earliest-branching metazoan taxon, and therefore, they have great significance in the reconstruction of early metazoan evolution. Yet, the phylogeny and systematics of sponges are to some extent still unresolved, and there is an on-going debate about the exact branching pattern of their main clades and their relationships to the other non-bilaterian animals. Here, we review the current state of the deep phylogeny of sponges. Several studies have suggested that sponges are paraphyletic. However, based on recent phylogenomic analyses, we suggest that the phylum Porifera could well be monophyletic, in accordance with cladistic analyses based on morphology. This finding has many implications for the evolutionary interpretation of early animal traits and sponge development. We further review the contribution that mitochondrial genes and genomes have made to sponge phylogenetics and explore the current state of the molecular phylogenies of the four main sponge lineages (Classes), that is, Demospongiae, Hexactinellida, Calcarea, and Homoscleromorpha, in detail. While classical systematic systems are largely congruent with molecular phylogenies in the class Hexactinellida and in certain parts of Demospongiae and Homoscleromorpha, the high degree of incongruence in the class Calcarea still represents a challenge. We highlight future areas of research to fill existing gaps in our knowledge. By reviewing sponge development in an evolutionary and phylogenetic context, we support previous suggestions that sponge larvae share traits and complexity with eumetazoans and that the simple sedentary adult lifestyle of sponges probably reflects some degree of secondary simplification. In summary, while deep sponge phylogenetics has made many advances in the past years, considerable efforts are still required to achieve a

  13. Hα Emitting Galaxies in the Deep And Wide Narrowband Survey

    NASA Astrophysics Data System (ADS)

    Gonzalez, Alicia; Malhotra, Sangeeta; Rhoads, James E.; DAWN collaboration

    2016-06-01

    We present new measurements of the Hα luminosity function (LF) and star formation rate (SFR) volume density for galaxies at z∼0.62. Our results are part of the Deep And Wide Narrowband Survey (DAWN), a unique infrared imaging program with large areal coverage (∼1.1 deg2 over 5 fields) and sensitivity (9.9 × 10‑18 erg/cm2/s at 5σ). The present sample, based on a single DAWN field, contains 85 Hα emission-line candidates at z∼0.62, 25% of which have spectroscopic confirmations. These candidates have been selected through comparison of narrow and broad-band images and through matching with existing catalogs in the COSMOS field. The dust-corrected LF is well described by a Schechter function. We calculate a SFR density of ρSFR =10(‑1.15±0.07) M○ / yr/ Mpc3. We compare our results to already existing surveys at similar redshifts and find that our faint slope of the LF is flatter than that of most other surveys and that our SFR density is higher than that reported from similar surveys at z<2.

  14. Field Galaxy Evolution with the MUNICS Survey

    NASA Astrophysics Data System (ADS)

    Drory, Niv; Feulner, Georg; Hopp, Ulrich; Snigula, Jan; Bender, Ralf

    The Munich Near-IR Cluster Survey (MUNICS) is a K'-selected survey uniformly covering 1 square degree in the J and K' near-IR bands. The survey area consists of 8 13.2 × 26.2 arcmin randomly selected fields at high galactic latitude, as well as 13 7 × 7 arcmin fields targeted towards 0.6 < z <1.5 QSOs. The 3 σ detection limits for a point source are 19.5 in the K'-band and 21.5 in the J-band. The data have been acquired at the 3.5m telescope at Calar Alto Observatory using the Ω - Prime camera. Optical photometry in the V, R, and I bands was obtained for a subsample of the survey fields covering 0.35 square degrees in total. These data have been obtained at the 2.2m telescope at Calar Alto Observatory and the 2.7m telescope at McDonald Observatory. These data enable us to determine photometric redshifts for the galaxies and thus are of great importance in selecting and confirming cluster candidates as well as individual galaxies for follow-up spectroscopy. The project has two main scientific aims, namely - the identification of galaxy clusters at redshifts around unity, and - the selection of a fair sample of field early-type galaxies at similar redshifts for evolutionary studies. Near-IR selection is an efficient tool for tracing the massive galaxy population at redshifts around unity because of its high sensitivity for evolved stellar populations even in the presence of moderate star formation activity. The formation and evolution of the population of massive galaxies is still a matter of lively and controversial debate. While models of hierarchical galaxy formation consistently predict a steep decline in the number density of massive spheroidals, they have a rather large number of free parameters, some of which involve ill-understood processes. Observation has not yet been successful in constraining the ranges of the involved model parameters tightly enough, so that comparisons between theory and experiment are difficult to interpret.

  15. CANDELS: The Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey

    NASA Technical Reports Server (NTRS)

    Grogin, Norman A.; Koekemoer, anton M.; Faber, S. M.; Ferguson, Henry C.; Kocevski, Dale D.; Riess, Adam G.; Acquaviva, Viviana; Alexander, David M.; Almaini, Omar; Ashby, Matthew L. N.; Barden, Marco; Bell, Eric F.; Bournaud, Frederic; Brown, Thomas M.; Caputi, Karina I.; Casertano, Stefano; Cassata, Paolo; Challis, Peter; Chary, Ranga-Ram; Cheung, Edmond; Cirasuolo, Michele; DeMello, Duilla; Gardner, Jonathan P.; Straughn, Amber N.

    2011-01-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, from z approx. 8 - 1.5. It will image > 250,000 distant galaxies using three separate cameras on the Hubble Space Tele8cope, from the mid-UV to near-IR, and will find and measure Type Ia supernovae beyond z > 1.5 to test their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10(exp 9) solar mass to z approx. 2, reaching the knee of the UV luminosity function of galaxies to z approx. 8. The survey covers approximately 800 square arc minutes and is divided into two parts. The CANDELS/Deep survey (5(sigma) point-source limit H =27.7mag) covers approx. 125 square arcminutes within GOODS-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (EGS, COSMOS, and UDS) and covers the full area to a 50(sigma) point-source limit of H ? or approx. = 27.0 mag. Together with the Hubble Ultradeep Fields, the strategy creates a three-tiered "wedding cake" approach that has proven efficient for extragalactic surveys. Data from the survey are non-proprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design.

  16. When is stacking confusing? The impact of confusion on stacking in deep H I galaxy surveys

    NASA Astrophysics Data System (ADS)

    Jones, Michael G.; Haynes, Martha P.; Giovanelli, Riccardo; Papastergis, Emmanouil

    2016-01-01

    We present an analytic model to predict the H I mass contributed by confused sources to a stacked spectrum in a generic H I survey. Based on the ALFALFA (Arecibo Legacy Fast ALFA) correlation function, this model is in agreement with the estimates of confusion present in stacked Parkes telescope data, and was used to predict how confusion will limit stacking in the deepest Square Kilometre Array precursor H I surveys. Stacking with LADUMA (Looking At the Distant Universe with MeerKAT) and DINGO UDEEP (Deep Investigation of Neutral Gas Origins - Ultra Deep) data will only be mildly impacted by confusion if their target synthesized beam size of 10 arcsec can be achieved. Any beam size significantly above this will result in stacks that contain a mass in confused sources that is comparable to (or greater than) that which is detectable via stacking, at all redshifts. CHILES (COSMOS H I Large Extragalactic Survey) 5 arcsec resolution is more than adequate to prevent confusion influencing stacking of its data, throughout its bandpass range. FAST (Five hundred metre Aperture Spherical Telescope) will be the most impeded by confusion, with H I surveys likely becoming heavily confused much beyond z = 0.1. The largest uncertainties in our model are the redshift evolution of the H I density of the Universe and the H I correlation function. However, we argue that the two idealized cases we adopt should bracket the true evolution, and the qualitative conclusions are unchanged regardless of the model choice. The profile shape of the signal due to confusion (in the absence of any detection) was also modelled, revealing that it can take the form of a double Gaussian with a narrow and wide component.

  17. The infrared medium-deep survey. II. How to trigger radio AGNs? Hints from their environments

    SciTech Connect

    Karouzos, Marios; Im, Myungshin; Kim, Jae-Woo; Lee, Seong-Kook; Jeon, Yiseul; Choi, Changsu; Hong, Jueun; Hyun, Minhee; Jun, Hyunsung David; Kim, Dohyeong; Kim, Yongjung; Kim, Ji Hoon; Kim, Duho; Park, Won-Kee; Taak, Yoon Chan; Yoon, Yongmin; Chapman, Scott; Pak, Soojong; Edge, Alastair

    2014-12-10

    Activity at the centers of galaxies, during which the central supermassive black hole is accreting material, is nowadays accepted to be rather ubiquitous and most probably a phase of every galaxy's evolution. It has been suggested that galactic mergers and interactions may be the culprits behind the triggering of nuclear activity. We use near-infrared data from the new Infrared Medium-Deep Survey and the Deep eXtragalactic Survey of the VIMOS-SA22 field and radio data at 1.4 GHz from the FIRST survey and a deep Very Large Array survey to study the environments of radio active galactic nuclei (AGNs) over an area of ∼25 deg{sup 2} and down to a radio flux limit of 0.1 mJy and a J-band magnitude of 23 mag AB. Radio AGNs are predominantly found in environments similar to those of control galaxies at similar redshift, J-band magnitude, and (M{sub u} – M{sub r} ) rest-frame color. However, a subpopulation of radio AGNs is found in environments up to 100 times denser than their control sources. We thus preclude merging as the dominant triggering mechanism of radio AGNs. By fitting the broadband spectral energy distribution of radio AGNs in the least and most dense environments, we find that those in the least dense environments show higher radio-loudness, higher star formation efficiencies, and higher accretion rates, typical of the so-called high-excitation radio AGNs. These differences tend to disappear at z > 1. We interpret our results in terms of a different triggering mechanism for these sources that is driven by mass loss through winds of young stars created during the observed ongoing star formation.

  18. The Infrared Medium-Deep Survey. II. How to Trigger Radio AGNs? Hints from their Environments

    NASA Astrophysics Data System (ADS)

    Karouzos, Marios; Im, Myungshin; Kim, Jae-Woo; Lee, Seong-Kook; Chapman, Scott; Jeon, Yiseul; Choi, Changsu; Hong, Jueun; Hyun, Minhee; Jun, Hyunsung David; Kim, Dohyeong; Kim, Yongjung; Kim, Ji Hoon; Kim, Duho; Pak, Soojong; Park, Won-Kee; Taak, Yoon Chan; Yoon, Yongmin; Edge, Alastair

    2014-12-01

    Activity at the centers of galaxies, during which the central supermassive black hole is accreting material, is nowadays accepted to be rather ubiquitous and most probably a phase of every galaxy's evolution. It has been suggested that galactic mergers and interactions may be the culprits behind the triggering of nuclear activity. We use near-infrared data from the new Infrared Medium-Deep Survey and the Deep eXtragalactic Survey of the VIMOS-SA22 field and radio data at 1.4 GHz from the FIRST survey and a deep Very Large Array survey to study the environments of radio active galactic nuclei (AGNs) over an area of ~25 deg2 and down to a radio flux limit of 0.1 mJy and a J-band magnitude of 23 mag AB. Radio AGNs are predominantly found in environments similar to those of control galaxies at similar redshift, J-band magnitude, and (Mu - Mr ) rest-frame color. However, a subpopulation of radio AGNs is found in environments up to 100 times denser than their control sources. We thus preclude merging as the dominant triggering mechanism of radio AGNs. By fitting the broadband spectral energy distribution of radio AGNs in the least and most dense environments, we find that those in the least dense environments show higher radio-loudness, higher star formation efficiencies, and higher accretion rates, typical of the so-called high-excitation radio AGNs. These differences tend to disappear at z > 1. We interpret our results in terms of a different triggering mechanism for these sources that is driven by mass loss through winds of young stars created during the observed ongoing star formation.

  19. Spitzer Survey of the Large Magellanic Cloud: Surveying the Agents of a Galaxy's Evolution (SAGE)

    NASA Astrophysics Data System (ADS)

    Meixner, Margaret; Babler, Brian; Bernard, Jean-Philippe; Blum, Robert; Boulanger, Francois; Churchwell, Edward; Cohen, Martin; Engelbracht, Charles; Frogel, Jay; Fukui, Yasuo; Gallagher, Jay; Gordon, Karl; Gorjian, Varoujan; Harris, Jason; Hora, Joseph; Indebetouw, Remy; Jansen, Stephen; Kawamura, Akiko; Kelly, Douglas; Kemper, Ciska; Latter, William; Leitherer, Claus; Madden, Suzanne; Meade, Marilyn; Misselt, Karl; Mizuno, Norikazu; Mizuno, Akira; Mould, Jeremy; Nota, Antonella; Oey, Sally; Olsen, Knut; Onishi, Toshikazu; Paladini, Roberta; Panagia, Nino; Perez-Gonzalez, Pablo; Reach, William; Shibai, Hiroshi; Shuji, Sato; Smith, Linda; Staveley-Smith, Lister; Tielens, Xander; Ueta, Toshiya; van Dyk, Schuyler; Volk, Kevin; Werner, Michael; Whitney, Barbara; Zaritsky, Dennis

    2005-06-01

    The recycling of matter between the interstellar medium (ISM) and stars drives the evolution of a galaxy's visible matter. To understand this recycling, we propose to study the physical processes of the ISM, the formation of new stars and the injection of mass by evolved stars and their relationships on the galaxy-wide scale of the Large Magellanic Cloud (LMC). Due to its proximity, favorable viewing angle, multi-wavelength information, and measured tidal interactions with the Milky Way (MW) and Small Magellanic Cloud (SMC), the LMC is uniquely suited for surveying the agents of a galaxy's evolution (SAGE), the ISM and stars. Our uniform and unbiased survey of the LMC (7x7 degrees) in all IRAC and MIPS bands will have much better wavelength coverage, up to ~1000 times better point source sensitivity and ~11 times better angular resolution than previous IR surveys. Full and uniform coverage of the LMC is necessary to study the galaxy as a system, to develop a template for more distant galaxies and to create an archival data set (rights waived) that promises a lasting legacy to match current LMC surveys at other wavelengths. SAGE will reveal over 6 million sources including ~150,000 evolved stars, ~50,000 young stellar objects and the diffuse ISM with column densities >1.2e21 H/cm2. In contrast to the MW and SMC, the diffuse IR emission in the LMC can be unambiguously associated with individual gas/dust clouds, thereby permitting unique studies of dust processes in the ISM. SAGE's complete census of newly formed stars with masses >1-3 Msun will reveal whether tidally-triggered star formation events in the LMC are sustained or short-lived. SAGE's complete census of evolved stars with mass loss rates >1e-8 Msun/yr will quantitatively measure the rate at which evolved stars inject mass into the ISM. SAGE will be the crucial link between Spitzer's survey of individual IR sources in the MW (GLIMPSE) and its surveys of galaxies (e.g., SINGS) and a stepping stone to the

  20. Deep Near-Infrared Survey toward the M17 Region

    NASA Astrophysics Data System (ADS)

    Jiang, Zhibo; Yao, Yongqiang; Yang, Ji; Ando, Minoru; Kato, Daisuke; Kawai, Toshihide; Kurita, Mikio; Nagata, Tetsuya; Nagayama, Takahiro; Nakajima, Yasushi; Nagashima, Chie; Sato, Shuji; Tamura, Motohide; Nakaya, Hidehiko; Sugitani, Koji

    2002-09-01

    We conducted a deep JHKs-band imaging survey of the M17 region, using a near-infrared camera, the Simultaneous 3-color InfraRed Imager for Unbiased Survey (SIRIUS), mounted on the InfraRed Survey Facility (IRSF) 1.4 m telescope at the South African Astronomical Observatory. This survey covers an area of ~200 arcmin2 with 10 σ limiting magnitudes of J~18.7, H~18.2, and Ks~17.5. The near-infrared (NIR) images reveal an unprecedented view of the region. The NIR nebulae are highly structured, with two nebular bars corresponding to, but a little larger than, the H II region defined by Felli, Massi, & Churchwell, constructing a conical shape. Fine structures are found all over the nebular area. The central region contains a congregation of intermediate- to high-mass stars. From the slope of the Ks-band luminosity function and the frequency of young stellar objects (YSOs) we infer that the central cluster has an age less than 3 Myr. The central OB cluster provides tremendous energy that heats and ionizes its surrounding materials, triggering the star formation of second-generation in the nebular bars. The second generation stars are so numerous that could they affect the star formation efficiency in the whole region. To the southwest of the central cluster and the nebular bars, where a giant molecular cloud core is located, a large number of red stars are detected. We argue that these red stars are most probably associated YSOs with intrinsic color excesses, not normal field stars reddened by the molecular cloud in front of them. Being located beyond the photodissociation region, the star-forming process in the molecular region could be independent of the impact of the central cluster.

  1. ESO imaging survey. Deep public survey: Multi-color optical data for the Chandra Deep Field South

    NASA Astrophysics Data System (ADS)

    Arnouts, S.; Vandame, B.; Benoist, C.; Groenewegen, M. A. T.; da Costa, L.; Schirmer, M.; Mignani, R. P.; Slijkhuis, R.; Hatziminaoglou, E.; Hook, R.; Madejsky, R.; Rité, C.; Wicenec, A.

    2001-11-01

    This paper presents multi-passband optical data obtained from observations of the Chandra Deep Field South (CDF-S), located at alpha ~ 3h 32m, delta ~ -27o 48'. The observations were conducted at the ESO/MPG 2.2 m telescope at La Silla using the 8kx8k Wide-Field Imager (WFI). This data set, taken over a period of one year, represents the first field to be completed by the ongoing Deep Public Survey (DPS) being carried out as a part of the ESO Imaging Survey (EIS) project. This paper describes the optical observations, the techniques employed for un-supervised pipeline processing and the general characteristics of the final data set. Image processing has been performed using multi-resolution image decomposition techniques adapted to the EIS pipeline. The automatic processing steps include standard de-bias and flat-field, automatic removal of satellite tracks, de-fringing/sky-subtraction, image stacking/mosaicking and astrometry. Stacking of dithered images is carried out using pixel-based astrometry which enables the efficient removal of cosmic rays and image defects, yielding remarkably clean final images. The final astrometric calibration is based on a pre-release of the GSC-II catalog and has an estimated intrinsic accuracy of la 0.10 arcsec, with all passbands sharing the same solution. The paper includes data taken in six different filters (U'UBVRI). The data cover an area of about 0.25 square degrees reaching 5sigma limiting magnitudes of U'AB=26.0, UAB=25.7, BAB=26.4, VAB=25.4, RAB=25.5 and IAB= 24.7 mag, as measured within a 2 x FWHM aperture. The optical data covers an area of ~ 0.1 square degrees for which moderately deep observations in two near-infrared bands are also available, reaching 5sigma limiting magnitudes of JAB ~ 23.4 and KAB ~ 22.6. The current optical/infrared data also fully encompass the region of the deep X-ray observations recently completed by the Chandra telescope. The optical data presented here, as well as the infrared data released

  2. A 6 GHz Synoptic Survey of the COSMOS Deep Field with the JVLA

    NASA Astrophysics Data System (ADS)

    Sink, Joseph R.; Myers, Steven T.

    2016-01-01

    The Cosmic Evolution Survey (COSMOS) covers two square degrees, and is observed over a large portion of the electromagnetic spectrum from X-ray to Radio. Key science goals of COSMOS include probing the evolution of galaxies, AGN, and large scale structures of the Universe. As well as constraining cosmological models and the star and structure formation history of the Universe. The wide range of frequencies and deep surveys are suitable for many astrophysical studies.Beginning in 2013, observations of the COSMOS field in C-band (4 - 8 GHz) using the JVLA have been carried out in every configuration spanning 21 months (April 2013 - Jan 2015) for a total of 13 observations. The observations are comprised of 1 hour time blocks using a technique called On-The-Fly Mosaicking (OTFM). Using OTFM we see an increased efficiency for an allotted observation block by collecting data as the array scans across the field, rather than a pointed mosaic which requires settle down time after each new pointing. Each observation consists of 2160 1-second integrations on 432 phase centers that require calibration and image processing before they can be mosaicked to create the final image of the entire COSMOS field.The primary science goal of this survey is to identify, catalog, and study the variable and transient radio sources in the COSMOS field, comparing these to other radio, optical, IR, and X-ray observations. The main class of variables we are interested in Active Galactic Nuclei.

  3. Simulation of deep one- and two-dimensional redshift surveys

    NASA Technical Reports Server (NTRS)

    Park, Changbom; Gott, J. Richard, III

    1991-01-01

    It is shown that slice or pencil-beam redshift surveys of galaxies can be simulated in a box with nonequal sides. This method saves a lot of computer time and memory while providing essentially the same results as from whole-cube simulations. A 2457.6/h Mpc-long rod (out to a redshift z = 0.58 in two opposite directions) is simulated using the standard biased cold dark matter model as an example to mimic the recent deep pencil-beam surveys by Broadhurst et al. (1990). The structures (spikes) seen in these simulated samples occur when the narrow pencil-beam pierces walls, filaments, and clusters appearing randomly along the line-of-sight. A statistical test for goodness of fit to a periodic lattice has been applied to the observations and the simulations. It is found that the statistical significance level (P = 15.4 percent) is not strong enough to reject the null hypothesis that the observations and the simulations were drawn at random from the same set.

  4. Collective Landmarks for Deep Time: A New Tool for Evolution Education

    ERIC Educational Resources Information Center

    Delgado, Cesar

    2014-01-01

    Evolution is a fundamental, organising concept in biology, yet there is widespread resistance to evolution among US students and there are rising creationist challenges in Europe. Resistance to evolution is linked to lack of understanding of the age of the Earth. An understanding of deep time is thus essential for effective biology education.…

  5. A Deep XMM-Newton Legacy Survey of M33

    NASA Astrophysics Data System (ADS)

    Williams, Benjamin

    We propose for financial support that will allow us to reduce and analyze all XMM- Newton data relevant to an A09 deep XMM-Newton legacy survey of M33 covering the entire optical disk with a total of 700000 seconds of exposure time. These data will allow us to determine how the temperature and energetics of the hot interstellar medium (ISM) are affected by star formation, constrain the nature and dynamical masses of new pulsating and eclipsing X-ray binaries, and perform detailed statistical and spectral studies on the largest known extragalactic population of X-ray supernova remnants (SNRs). The support proposed here is crucial for the full analysis and publication of the entire data set. Measurements and model fitting of the spectra and timing of all of the discrete sources detected in our data will constrain the nature and dynamical masses of new pulsating and eclipsing X-ray binaries, as well as provide new insight into the origins of the X-ray SNRs. Spatially-resolved, spectral studies of the diffuse emission will allow us to determine how the temperature and energetics of the hot interstellar medium (ISM) are affected by star formation. Several members of our team have already performed similar analysis to those proposed using data from the deep Chandra ACIS-I survey of M33 (ChASeM33), and we intend to hire a postdoctoral research associate who has experience working with large XMM-Newton data sets. Therefore the techniques for making the measurements are well-understood; however, the deep Chandra ACIS-I survey of M33 does not provide sufficient soft response for detailed spectral measurements of the diffuse gas emission from dozens of individual star forming regions. To reliably determine the temperature structure of the interstellar gas of these regions, our simulations show that we need to go a factor of 10 deeper in the soft X-ray band than existing X-ray data, which will be achieved with our proposed observations. Furthermore, XMM-Newton studies of X

  6. Identifying Luminous AGN in Deep Surveys: Revised IRAC Selection Criteria

    NASA Astrophysics Data System (ADS)

    Donley, Jennifer; Koekemoer, A. M.; Brusa, M.; Capak, P.; Cardamone, C. N.; Civano, F.; Ilbert, O.; Impey, C. D.; Kartaltepe, J.; Miyaji, T.; Salvato, M.; Sanders, D. B.; Trump, J. R.; Zamorani, G.

    2012-01-01

    Spitzer IRAC selection is a powerful tool for identifying luminous AGN. The AGN selection wedges currently in use, however, are heavily contaminated by star-forming galaxies, especially at high redshift. Using the large samples of luminous AGN and high-redshift star-forming galaxies in COSMOS, we redefine the AGN selection criteria for use in deep IRAC surveys. The new IRAC criteria are designed to be both highly complete and reliable, and incorporate the best aspects of the current AGN selection wedges and of infrared power-law selection while excluding high redshift star-forming galaxies selected via the BzK, DRG, LBG, and SMG criteria. At QSO-luminosities of log L(2-10 keV)>44, the new IRAC criteria recover 75% of the hard X-ray and IRAC-detected XMM-COSMOS sample, yet only 37% of the IRAC AGN candidates have X-ray counterparts, a fraction that rises to 51% in regions with Chandra exposures of 50-160 ks. X-ray stacking of the individually X-ray non-detected AGN candidates leads to a hard X-ray signal indicative of heavily obscured to mildly Compton-thick obscuration (log NH >= 23.7). While IRAC selection recovers a substantial fraction of luminous unobscured and obscured AGN, it is incomplete to low-luminosity and host-dominated AGN.

  7. Asteroid Size-Frequency Distribution (The ISO Deep Asteroid Survey)

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    2001-01-01

    A total of six deep exposures (using AOT CAM01 with a 6" PFOV) through the ISOCAM LW10 filter (IRAS Band 1, i.e., 12 micro-m) were obtained on an approximately 15 arcminute square field centered on the ecliptic plane. Point sources were extracted using the technique described by Desert, et al. Two known asteroids appear in these frames and 20 sources moving with velocities appropriate for main belt asteroids are present. Most of the asteroids detected have flux densities less than 1 mJy, i.e., between 150 and 350 times fainter than any of the asteroids observed by Infrared Astronomy Satellite (IRAS). These data provide the first direct measurement of the 12 micro-m sky-plane density for asteroids on the ecliptic equator. The median zodiacal foreground, as measured by ISOCAM during this survey, is found to be 22.1 +/- 1.5 mJy per pixel, i.e., 26.2 +/- 1.7 MJy/sr. The results presented here imply that the actual number of kilometer-sized asteroids is significantly greater than previously believed and in reasonable agreement with the Statistical Asteroid Model.

  8. The Spitzer Ultra-Deep Survey of the HST/ERS Field

    NASA Astrophysics Data System (ADS)

    Fazio, Giovanni; Soifer, Tom; Willner, Steven; Ashby, Matt; Hora, Joseph; Huang, Jiasheng; Wang, Zhong

    2011-02-01

    The HST WFC3 Early Release Science (ERS) observations in the GOODS South field, together with the existing HST ACS observations provide a panchromatic 10-band survey of the ERS field that cover 40-50 square arcmin over the wavelength interval 0.2 to 1.7 microns to WFC3/IR depths of AB ~ 27.3 mag (5 sigma) for point sources. Such a deep, multiwavelegth survey provides a unique opportunity to study galaxy evolution out to z ~ 8 and even possibly to z ~ 10. These early galaxies are important because they serve as beacons of the first sites of star formation, as a constraint on galaxy formation models, and as probes of reionization. The only limitation to even further progress in exploring the early universe using the ERS data is the current depth of Spitzer/IRAC mid-infrared data in this field. IRAC adds the unique and important capability of tracing early galaxy stellar mass growth, stellar ages, and star formation rates back to z ~ 7 - 10. In this DDT program we propose significantly increasing the IRAC depth achieved in a 5'x5' area in the ERS field to ~ 27 AB mag (5 sigma, 3.6 micron). This probe of the early Universe to such a depth by HST and Spitzer/IRAC, will have a major impact on our knowledge of the galaxy evolution and leave an important legacy for years to come.

  9. A Deep Multicolor Survey. VII. Extremely Red Objects and Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Martini, Paul

    2001-05-01

    Extremely red objects (EROs) offer a window to the universe at z~1 analogous to that provided by the Lyman break galaxies at z=3. Passive evolution and hierarchical galaxy formation models make very distinct predictions for the K (2.2 μm) surface density of galaxies at z~1, and EROs are a powerful constraint on these theories. I present a study of nine resolved EROs with R-K>=5.3 and K<=18 mag found in the 185 arcmin2 of the Deep Multicolor Survey with near-infrared imaging. Photometric redshifts for these galaxies show they all lie at z=0.8-1.3. The relatively blue J-K colors of these galaxies suggest that most are old elliptical galaxies rather than dusty starbursts. The surface density of EROs in this survey (>0.05 arcmin-2), which is a lower limit to the total z~1 galaxy surface density, is an order of magnitude below the prediction of passive galaxy evolution, yet over a factor of 2 higher than the hierarchical galaxy formation prediction for a flat, matter-dominated universe. A flat, Λ-dominated universe may bring the hierarchical galaxy formation model into agreement with the observed ERO surface density. Based on observations obtained at MDM Observatory, operated by Columbia University, Dartmouth College, the University of Michigan, and the Ohio State University.

  10. Galaxy Evolution Within the Kilo-Degree Survey

    NASA Astrophysics Data System (ADS)

    Tortora, C.; Napolitano, N. R.; La Barbera, F.; Roy, N.; Radovich, M.; Getman, F.; Brescia, M.; Cavuoti, S.; Capaccioli, M.; Longo, G.

    The ESO Public Kilo-Degree Survey (KiDS) is an optical wide-field imaging survey carried out with the VLT Survey Telescope and the OmegaCAM camera. KiDS will scan 1,500 deg2 in four optical filters (u, g, r, i). Designed to be a weak lensing survey, it is ideal for galaxy evolution studies, thanks to the high spatial resolution of VST, the excellent seeing and the photometric depth. The surface photometry has provided with structural parameters (e.g. size and Sérsic index), aperture and total magnitudes have been used to obtain photometric redshifts from Machine Learning methods and stellar masses/luminositites from stellar population synthesis. Our project aimed at investigating the evolution of the colour and structural properties of galaxies with mass and environment up to redshift z ˜ 0.5 and more, to put constraints on galaxy evolution processes, as galaxy mergers.

  11. On the use of seismic reflection surveys from oil exploration in deep crustal studies

    NASA Astrophysics Data System (ADS)

    Rotstein, Y.; Trachtman, P.

    1986-09-01

    A very large number of seismic reflection surveys is carried out by the oil industry throughout the world. Some of these surveys are designed to study deep oil traps and may use field parameters which, for the most part, are not significantly different from those used in deep crustal reflection studies. The one parameter which always varies is the record length (listening time). In the case of a vibratory source, the record length can be increased at the processing stage by the equivalent reduction of vibration time through partial correlation. We have used an oil exploration survey from a deep sedimentary basin in the coastal plain of Israel and extended its record length using this technique. We show that if a survey with appropriated field parameters, i.e., a survey for a deep target is chosen, deep crustal reflectors can be traced. Since a COCORP type deep crustal reflection study was also carried out in the same region, we can compare the two sets of results. We note that in this case the extended oil exploration record is at least equivalent to, and probably of better quality than, the COCORP type survey. This result is due mostly to a better S/N ratio in the oil exploration survey where input power was significantly larger than in special purpose study. This result indicates the as yet untapped potential of oil exploration data in deep continental crustal studies.

  12. DISK EVOLUTION IN OB ASSOCIATIONS: DEEP SPITZER/IRAC OBSERVATIONS OF IC 1795

    SciTech Connect

    Roccatagliata, Veronica; Bouwman, Jeroen; Henning, Thomas; Gennaro, Mario; Sicilia-Aguilar, Aurora; Feigelson, Eric; Kim, Jinyoung Serena; Lawson, Warrick A.

    2011-06-01

    We present a deep Spitzer/Infrared Array Camera (IRAC) survey of the OB association IC 1795 carried out to investigate the evolution of protoplanetary disks in regions of massive star formation. Combining Spitzer/IRAC data with Chandra/Advanced CCD Imaging Spectrometer observations, we find 289 cluster members. An additional 340 sources with an infrared excess, but without X-ray counterpart, are classified as cluster member candidates. Both surveys are complete down to stellar masses of about 1 M{sub sun}. We present pre-main-sequence isochrones computed for the first time in the Spitzer/IRAC colors. The age of the cluster, determined via the location of the Class III sources in the [3.6]-[4.5]/[3.6] color-magnitude diagram, is in the range of 3-5 Myr. As theoretically expected, we do not find any systematic variation in the spatial distribution of disks within 0.6 pc of either O-type star in the association. However, the disk fraction in IC 1795 does depend on the stellar mass: sources with masses >2 M{sub sun} have a disk fraction of {approx}20%, while lower mass objects (2-0.8 M{sub sun}) have a disk fraction of {approx}50%. This implies that disks around massive stars have a shorter dissipation timescale.

  13. A deep imaging survey of the Pleiades with ROSAT

    NASA Technical Reports Server (NTRS)

    Stauffer, J. R.; Caillault, J.-P.; Gagne, M.; Prosser, C. F.; Hartmann, L. W.

    1994-01-01

    We have obtained deep ROSAT images of three regions within the Pleiades open cluster. We have detected 317 X-ray sources in these ROSAT Position Sensitive Proportional Counter (PSPC) images, 171 of which we associate with certain or probable members of the Pleiades cluster. We detect nearly all Pleiades members with spectral types later than G0 and within 25 arcminutes of our three field centers where our sensitivity is highest. This has allowed us to derive for the first time the luminosity function for the G, K, amd M dwarfs of an open cluster without the need to use statistical techniques to account for the presence of upper limits in the data sample. Because of our high X-ray detection frequency down to the faint limit of the optical catalog, we suspect that some of our unidentified X-ray sources are previously unknown, very low-mass members of Pleiades. A large fraction of the Pleiades members detected with ROSAT have published rotational velocities. Plots of L(sub X)/L(sub Bol) versus spectroscopic rotational velocity show tightly correlated `saturation' type relations for stars with ((B - V)(sub 0)) greater than or equal to 0.60. For each of several color ranges, X-ray luminosities rise rapidly with increasing rotation rate until c sin i approximately equal to 15 km/sec, and then remains essentially flat for rotation rates up to at least v sin i approximately equal to 100 km/sec. The dispersion in rotation among low-mass stars in the Pleiades is by far the dominant contributor to the dispersion in L(sub X) at a given mass. Only about 35% of the B, A, and early F stars in the Pleiades are detected as X-ray sources in our survey. There is no correlation between X-ray flux and rotation for these stars. The X-ray luminosity function for the early-type Pleiades stars appears to be bimodal -- with only a few exceptions, we either detect these stars at fluxes in the range found for low-mass stars or we derive X-ray limits below the level found for most Pleiades

  14. Clustering at High Redshift: Precise Constraints from a Deep, Wide-Area Survey

    NASA Astrophysics Data System (ADS)

    Postman, Marc; Lauer, Tod R.; Szapudi, István; Oegerle, William

    1998-10-01

    We present constraints on the evolution of large-scale structure from a catalog of 710,000 galaxies with IAB <= 24 derived from a KPNO 4 m CCD imaging survey of a contiguous 4° × 4° region. The advantage of using large contiguous surveys for measuring clustering properties on even modest angular scales is substantial: the effects of cosmic scatter are strongly suppressed. We provide highly accurate measurements of the two-point angular correlation function, ω(θ), as a function of magnitude on scales up to 1.5d. The amplitude of ω(θ) declines by a factor of ~10 over the range 16 <= I <= 20 but only by a factor of 2-3 over the range 20 < I <= 23. For a redshift dependence of the spatial correlation function, ξ(r), parameterized as ξ(r, z) = (r/r0)-γ(1 + z)-(3+ε), we find r0 = 5.2 +/- 0.4 h-1 Mpc, and ε >~ 0 for I <= 20. This is in good agreement with the results from local redshift surveys. At I > 20, our best-fit values shift toward lower r0 and more negative ε. A strong covariance between r0 and ε prevents us from rejecting ε > 0 even at faint magnitudes, but if ε > 1, we strongly reject r0 <~ 4 h-1 Mpc (comoving). The above expression for ξ(r, z) and our data give a correlation length of r0(z = 0.5) ~ 3.0 +/- 0.4 h-1 Mpc, about a factor of 2 larger than the correlation length at z = 0.5 derived from the Canada-France Redshift Survey (CFRS). The small volume sampled by the CFRS and other deep redshift probes, however, makes these spatial surveys strongly susceptible to cosmic scatter and will tend to bias their derived correlation lengths toward the low end. Our results are consistent with redshift distributions in which ~30%-50% of the galaxies at I = 23 lie at z > 1. The best-fit power-law slope of the correlation function remains independent of I magnitude for I <= 22. At fainter limits, there is a suggestive trend toward flatter slopes that occurs at fluxes consistent with similar trends seen by Neuschaffer & Windhorst and Campos and coworkers

  15. Deep Structure and Evolution of the Cyprus Arc, With Implications for the Tectonic Evolution of Anatolia

    NASA Astrophysics Data System (ADS)

    Wortel, M. J.; Spakman, W.; Govers, R.; Ben-Avraham, Z.

    2006-12-01

    This study addresses the easternmost segment of the convergent plate boundary in the Mediterranean, encompassing the Cyprus arc and its connection to the Arabia-Eurasia collision zone and the Dead Sea fault. Seismic activity along the arc is limited (certainly relative to the adjacent Hellenic arc). Although marine geophysical surveys have elucidated many pertinent features of the region, the plate boundary configuration is not well understood. Therefore, we use seismic tomography results to study the deep structure of this plate boundary segment. We find that the deep structure of the eastern part of the Cyprus arc, exhibiting a broad zone of sinistral deformation at the surface, is very similar to the eastern segment of the Hellenic subduction zone. A slab related anomaly is missing here in the upper mantle, and this part can be identified as a STEP fault zone (Subduction-Transform Edge Propagator; see Govers and Wortel, EPSL, v. 236, p. 505-523, 2005), allowing S-SW directed slab retreat. We propose that the inception of the STEP fault and the associated back-arc extension is triggered by the continental collision and subsequent slab detachment in the Bitlis suture to the east. From a quantitative analysis of tomographic anomalies in the mantle below the Bitlis suture zone (Hafkenscheid et al., JGR, v. 111, 2006) slab detachment is inferred to have taken place at 8-12 Ma, the younger end of this age range being more pertinent for the westernmost Bitlis segment. Slab detachment creates an edge to the subducting slab, which is a favourable condition for the inception of a STEP fault. The slab in the central part of the Cypus arc has become detached possibly resulting from the collision with the Eratosthenes Seamount in the (Late) Pliocene. Only in the northwestern segment of the arc below the Antalya Basin and the Isparta Angle the slab appears to be continuous. The short duration of the time window between inception of STEP faulting and collision with the

  16. EXTENDED PHOTOMETRY FOR THE DEEP2 GALAXY REDSHIFT SURVEY: A TESTBED FOR PHOTOMETRIC REDSHIFT EXPERIMENTS

    SciTech Connect

    Matthews, Daniel J.; Newman, Jeffrey A.; Coil, Alison L.; Cooper, Michael C.; Gwyn, Stephen D. J. E-mail: janewman@pitt.edu E-mail: m.cooper@uci.edu

    2013-02-15

    This paper describes a new catalog that supplements the existing DEEP2 Galaxy Redshift Survey photometric and spectroscopic catalogs with ugriz photometry from two other surveys: the Canada-France-Hawaii Legacy Survey (CFHTLS) and the Sloan Digital Sky Survey (SDSS). Each catalog is cross-matched by position on the sky in order to assign ugriz photometry to objects in the DEEP2 catalogs. We have recalibrated the CFHTLS photometry where it overlaps DEEP2 in order to provide a more uniform data set. We have also used this improved photometry to predict DEEP2 BRI photometry in regions where only poorer measurements were available previously. In addition, we have included improved astrometry tied to SDSS rather than USNO-A2.0 for all DEEP2 objects. In total this catalog contains {approx}27, 000 objects with full ugriz photometry as well as robust spectroscopic redshift measurements, 64% of which have r > 23. By combining the secure and accurate redshifts of the DEEP2 Galaxy Redshift Survey with ugriz photometry, we have created a catalog that can be used as an excellent testbed for future photo-z studies, including tests of algorithms for surveys such as LSST and DES.

  17. Investigating the Local and High Redshift Universe With Deep Survey Data and Ground-Based Spectroscopy

    NASA Astrophysics Data System (ADS)

    Masters, Daniel Charles

    Large multiwavelength surveys are now driving the frontiers of astronomical research. I describe results from my work using data from two large astronomical surveys: the Cosmic Evolution Survey (COSMOS), which has obtained deep photometric and spectroscopic data on two square degrees of the sky using many of the most powerful telescopes in the world, and the WFC3 Infrared Spectroscopic Parallels (WISP) Survey, which uses the highly sensitive slitless spectroscopic capability of the Hubble Space Telescope Wide Field Camera 3 to detect star-forming galaxies over most of the universe's history. First I describe my work on the evolution of the high-redshift quasar luminosity function, an important observational quantity constraining the growth of the supermassive black holes in the early universe. I show that the number density of faint quasars declines rapidly above z ˜ 3. This result is discussed in the context of cosmic reionization and the coevolution of galaxies and their central black holes. Next I present results of a multi-year campaign of near-infrared spectroscopy with FIRE, a world-class near-infrared spectrometer on the Magellan Baade 6.5 meter telescope in Chile, targeting emission-line galaxies at z ˜ 2 discovered with the Hubble Space Telescope. Our results showed that the typical emission-line galaxy at this redshift has low-metallicity, low dust obscuration, high ionization parameter, and little evidence for significant active galactic nucleus (AGN) contribution to the emission lines. We also find evidence that high redshift star-forming galaxies have enhanced nitrogen abundances. This result has interesting implications for the nature of the star formation in such galaxies -- in particular, it could mean that a large fraction of such galaxies harbor substantial populations of Wolf-Rayet stars, which are massive, evolved stars ejecting large amounts of enriched matter into the interstellar medium. Finally, I will discuss the discovery of three

  18. Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- UDS Field

    NASA Astrophysics Data System (ADS)

    Faber, Sandra

    2010-09-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey {CANDELS}is designed to document the ?rst third of galactic evolution from z =8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IRand ACS. It will also find the first Type Ia SNe beyond z > 1.5 andestablish their accuracy as standard candles for cosmology. Fivepremier multi-wavelength sky regions are selected from the SpitzerExtragalactic Deep Survey {SEDS} to provide complementary IRAC imagingdata down to 26.5 AB mag, a unique resource for stellar masses at allredshifts. The use of ?ve widely separated ?elds mitigates cosmicvariance and yields statistically robust and complete samples ofgalaxies down to 10^9 solar masses out to z 8.The program merges two originally separate MCT proposals. The Faberprogram incorporates a ?Wide? imaging survey in three separate fieldsto 2 orbit depth over 0.2 sq. degrees, plus a ?Deep? imaging surveyto 12 orbit depth in the two GOODS regions over 0.04 sq. degrees.In combination with ultra-deep imaging from the Hubble Ultradeep Fieldprogram {GO 11563}, the result is a three-tiered strategy that ef?cientlysamples both bright/rare and faint/common extragalactic objects. TheFerguson program adds an extensive high-redshift Type Ia SNe search,plus ultraviolet "daytime" UVIS exposures in GOODS-N to exploit theCVZ opportunity in that field.This program, GO 12064, is part of the Wide mosaic survey, which has thefollowing field centers and sizes: Field ID RA{2000} Dec{2000} WFC3 Dim. PA on sky UDS 02 17 38 -05 12 02 4x11 270 COSMOS 10 00 31 +02 24 00 4x11 180 EGS 14 19 31 +52 54 10 3x15 41 Science highlights from the Wide program: * Underlying structural properties of galaxies as revealed by WFC3-IR images sensitive to older stars {beyond the 4000-A break} and less affected by dust than ACS. A key redshift is z 2, where star-formation peaks, QSOs are most abundant, and where restframe B-band is still accessible to WFC3. Sample questions include: - Structure in young

  19. A deep redshift survey of field galaxies. Comments on the reality of the Butcher-Oemler effect

    NASA Technical Reports Server (NTRS)

    Koo, David C.; Kron, Richard G.

    1987-01-01

    A spectroscopic survey of over 400 field galaxies has been completed in three fields for which we have deep UBVI photographic photometry. The galaxies typically range from B=20 to 22 and possess redshifts z from 0.1 to 0.5 that are often quite spiky in distribution. Little, if any, luminosity evolution is observed up to redshifts z approx 0.5. By such redshifts, however, an unexpectedly large fraction of luminous galaxies has very blue intrinsic colors that suggest extensive star formation; in contrast, the reddest galaxies still have colors that match those of present-day ellipticals.

  20. A Socratic Method for Surveying Students' Readiness to Study Evolution

    ERIC Educational Resources Information Center

    Stansfield, William D.

    2013-01-01

    Before beginning a series of presentations on evolution, it would be prudent to survey the general level of students' understanding of prerequisite basic concepts of reproduction, heredity, ontology, and phenotypic diversity so that teachers can avoid devoting time to well-known subjects of general knowledge and can spend more time on subjects…

  1. South China Sea Tectonics and Magnetics: Constraints from IODP Expedition 349 and Deep-tow Magnetic Surveys

    NASA Astrophysics Data System (ADS)

    Lin, J.; Li, C. F.; Kulhanek, D. K.; Zhao, X.; Liu, Q.; Xu, X.; Sun, Z.; Zhu, J.

    2014-12-01

    The South China Sea (SCS) is the largest low-latitude marginal sea in the world. Its formation and evolution are linked to the complex continental-oceanic tectonic interaction of the Eurasian, Pacific, and Indo-Australian plates. Despite its relatively small size and short history, the SCS has undergone nearly a complete Wilson cycle from continental break-up to seafloor spreading to subduction. In January-March 2014, Expedition 349 of the International Ocean Discovery Program (IODP) drilled five sites in the deep basin of the SCS. Three sites (U1431, U1433, and U1434) cored into oceanic basement near the fossil spreading center on the East and Southwest Subbasins, whereas Sites U1432 and U1435 are located near the northern continent/ocean boundary of the East Subbasin. Shipboard biostratigraphy based on microfossils preserved in sediment directly above or within basement suggests that the preliminary cessation age of spreading in both the East and Southwest Subbasins is around early Miocene (16-20 Ma); however, post-cruise radiometric dating is being conducted to directly date the basement basalt in these subbasins. Prior to the IODP drilling, high-resolution near-seafloor magnetic surveys were conducted in 2012 and 2013 in the SCS with survey lines passing near the five IODP drilling sites. The deep-tow surveys revealed detailed patterns of the SCS magnetic anomalies with amplitude and spatial resolutions several times better than that of traditional sea surface measurements. Preliminary results reveal several episodes of magnetic reversal events that were not recognized by sea surface measurements. Together the IODP drilling and deep-tow magnetic surveys provide critical constraints for investigating the processes of seafloor spreading in the SCS and evolution of a mid-ocean ridge from active spreading to termination.

  2. Viral evolution in deep time: lentiviruses and mammals.

    PubMed

    Gifford, Robert J

    2012-02-01

    Lentiviruses are a distinctive genus of retroviruses that cause chronic, persistent infections in mammals, including humans. The emergence of pandemic HIV type-1 (HIV-1) infection during the late 20th century shaped a view of lentiviruses as 'modern' viruses. However, recent research has revealed an entirely different perspective, elucidating aspects of an evolutionary relationship with mammals that extends across many millions of years. Such deep evolutionary history is likely to be typical of many host-virus systems, fundamentally underpinning their interactions in the present day. For this reason, establishing the deep history of virus and host interaction is key to developing a fully informed approach to tackling viral diseases. Here, I use the example of lentiviruses to illustrate how paleovirological, geographic and genetic calibrations allow observations of virus and host interaction across a wide range of temporal and spatial scales to be integrated into a coherent ecological and evolutionary framework. PMID:22197521

  3. White dwarfs in the UKIRT infrared deep sky survey data release

    SciTech Connect

    Tremblay, P.-E.; Kalirai, J. S.; Leggett, S. K.; Lodieu, N.; Bergeron, P.; Ludwig, H.-G.

    2014-06-20

    We have identified 8 to 10 new cool white dwarfs from the Large Area Survey (LAS) Data Release 9 of the United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS). The data set was paired with the Sloan Digital Sky Survey to obtain proper motions and a broad ugrizYJHK wavelength coverage. Optical spectroscopic observations were secured at Gemini Observatory and confirm the degenerate status for eight of our targets. The final sample includes two additional white dwarf candidates with no spectroscopic observations. We rely on improved one-dimensional model atmospheres and new multi-dimensional simulations with CO5BOLD to review the stellar parameters of the published LAS white dwarf sample along with our additional discoveries. Most of the new objects possess very cool atmospheres with effective temperatures below 5000 K, including two pure-hydrogen remnants with a cooling age between 8.5 and 9.0 Gyr, and tangential velocities in the range 40 km s{sup –1} ≤v {sub tan} ≤ 60 km s{sup –1}. They are likely thick disk 10-11 Gyr old objects. In addition, we find a resolved double degenerate system with v {sub tan} ∼ 155 km s{sup –1} and a cooling age between 3.0 and 5.0 Gyr. These white dwarfs could be disk remnants with a very high velocity or former halo G stars. We also compare the LAS sample with earlier studies of very cool degenerates and observe a similar deficit of helium-dominated atmospheres in the range 5000 < T {sub eff} (K) < 6000. We review the possible explanations for the spectral evolution from helium-dominated toward hydrogen-rich atmospheres at low temperatures.

  4. X-ray Evolution of Normal Galaxies in the 6 Ms Chandra Deep Field-South

    NASA Astrophysics Data System (ADS)

    Lehmer, Bret; Basu-Zych, Antara; Mineo, Stefano; Brandt, W. Niel; Eufrasio, Rafael T.; Fragos, Tassos; Hornschemeier, Ann E.; Luo, Bin; Xue, Yongquan; Bauer, Franz E.; Gilfanov, Marat; Kalogera, Vassiliki; Ranalli, Piero; Schneider, Donald P.; Shemmer, Ohad; Tozzi, Paolo; Trump, Jonathan R.; Vignali, Cristian; Wang, JunXian; Yukita, Mihoko; Zezas, Andreas

    2016-04-01

    I will discuss recent efforts to quantify the evolution of X-ray binary (XRB) populations through cosmic time using the 6 Ms Chandra Deep Field-South (CDF-S) survey. The formation of XRBs is sensitive to galaxy properties like stellar age and metallicity---properties that have evolved significantly in the broader galaxy population throughout cosmic history. I will show that scaling relations between X-ray emission from low-mass XRBs (LMXBs) with stellar mass (LX/M) and high-mass XRBs (HMXBs) with star-formation rate (LX/SFR) change significantly with redshift, such that LX(LMXB)/M ~ (1+z)^2-3 and LX(HMXB)/SFR ~ (1+z). These findings are consistent with population synthesis models, which attribute the increase in LMXB and HMXB scaling relations with redshift as being due to declining host galaxy stellar ages and metallicities, respectively. These findings have important implications for the X-ray emission from young, low-metallicity galaxies at high redshift, which are likely to be more X-ray luminous per SFR and play a significant role in the heating of the intergalactic medium.

  5. A single evolutionary innovation drives the deep evolution of symbiotic N2-fixation in angiosperms

    PubMed Central

    Werner, Gijsbert D. A.; Cornwell, William K.; Sprent, Janet I.; Kattge, Jens; Kiers, E. Toby

    2014-01-01

    Symbiotic associations occur in every habitat on earth, but we know very little about their evolutionary histories. Current models of trait evolution cannot adequately reconstruct the deep history of symbiotic innovation, because they assume homogenous evolutionary processes across millions of years. Here we use a recently developed, heterogeneous and quantitative phylogenetic framework to study the origin of the symbiosis between angiosperms and nitrogen-fixing (N2) bacterial symbionts housed in nodules. We compile the largest database of global nodulating plant species and reconstruct the symbiosis’ evolution. We identify a single, cryptic evolutionary innovation driving symbiotic N2-fixation evolution, followed by multiple gains and losses of the symbiosis, and the subsequent emergence of ‘stable fixers’ (clades extremely unlikely to lose the symbiosis). Originating over 100 MYA, this innovation suggests deep homology in symbiotic N2-fixation. Identifying cryptic innovations on the tree of life is key to understanding the evolution of complex traits, including symbiotic partnerships. PMID:24912610

  6. A single evolutionary innovation drives the deep evolution of symbiotic N2-fixation in angiosperms.

    PubMed

    Werner, Gijsbert D A; Cornwell, William K; Sprent, Janet I; Kattge, Jens; Kiers, E Toby

    2014-01-01

    Symbiotic associations occur in every habitat on earth, but we know very little about their evolutionary histories. Current models of trait evolution cannot adequately reconstruct the deep history of symbiotic innovation, because they assume homogenous evolutionary processes across millions of years. Here we use a recently developed, heterogeneous and quantitative phylogenetic framework to study the origin of the symbiosis between angiosperms and nitrogen-fixing (N2) bacterial symbionts housed in nodules. We compile the largest database of global nodulating plant species and reconstruct the symbiosis' evolution. We identify a single, cryptic evolutionary innovation driving symbiotic N2-fixation evolution, followed by multiple gains and losses of the symbiosis, and the subsequent emergence of 'stable fixers' (clades extremely unlikely to lose the symbiosis). Originating over 100 MYA, this innovation suggests deep homology in symbiotic N2-fixation. Identifying cryptic innovations on the tree of life is key to understanding the evolution of complex traits, including symbiotic partnerships. PMID:24912610

  7. The Observations of Redshift Evolution in Large Scale Environments (ORELSE) Survey

    NASA Astrophysics Data System (ADS)

    Squires, Gordon K.; Lubin, L. M.; Gal, R. R.

    2007-05-01

    We present the motivation, design, and latest results from the Observations of Redshift Evolution in Large Scale Environments (ORELSE) Survey, a systematic search for structure on scales greater than 10 Mpc around 20 known galaxy clusters at z > 0.6. When complete, the survey will cover nearly 5 square degrees, all targeted at high-density regions, making it complementary and comparable to field surveys such as DEEP2, GOODS, and COSMOS. For the survey, we are using the Large Format Camera on the Palomar 5-m and SuPRIME-Cam on the Subaru 8-m to obtain optical/near-infrared imaging of an approximately 30 arcmin region around previously studied high-redshift clusters. Colors are used to identify likely member galaxies which are targeted for follow-up spectroscopy with the DEep Imaging Multi-Object Spectrograph on the Keck 10-m. This technique has been used to identify successfully the Cl 1604 supercluster at z = 0.9, a large scale structure containing at least eight clusters (Gal & Lubin 2004; Gal, Lubin & Squires 2005). We present the most recent structures to be photometrically and spectroscopically confirmed through this program, discuss the properties of the member galaxies as a function of environment, and describe our planned multi-wavelength (radio, mid-IR, and X-ray) observations of these systems. The goal of this survey is to identify and examine a statistical sample of large scale structures during an active period in the assembly history of the most massive clusters. With such a sample, we can begin to constrain large scale cluster dynamics and determine the effect of the larger environment on galaxy evolution.

  8. Successful Completion of Pre-Site Survey for Deep Drilling at El'gygytgyn Crater Lake

    NASA Astrophysics Data System (ADS)

    Melles, M.; Minyuk, P.; Brigham-Grette, J.; Niessen, F.

    2003-12-01

    Lake El'gygytgyn, located in central Chukotka, NE Russia, is a 3.6 million year old impact crater lake with a diameter of 12 km and a water depth of 170 m. The sedimentary record of the lake has become a major focus of multi-disciplinary multi-national paleoclimatic research and is now a potential target for deep drilling. A full-length sediment core would yield a complete record of Arctic climate evolution, back one million years prior to the first major glaciation of the Northern Hemisphere. Geomorphological evidence from the catchment suggests that the crater was never glaciated during the entire Late Cenozoic. A 13.0 m long sediment core retrieved from the deepest part of the lake in 1998 revealed a basal age of approx. 300 ka, confirmed the lack of glacial erosion, and underlined the sensitivity of this lacustrine environment to reflect high resolution climatic change. The first single channel seismic survey carried out in 2000 discovered undisturbed and well-stratified sediments to a depth of 160 m below the lake floor. Refraction data from sonobuoys indicated the top of the impact breccia at about 360 m subbottom. An ICDP workshop held in 2001 recognised the unique potential of the lake for both paleoclimate and impact-related research and suggested more site survey work. This final pre-site survey expedition took place from April to September 2003. Modern process studies of the lake hydrology, limnology, meteorology, and sedimentology took place over this entire period to better understand the various proxies we are using to decipher the paleoclimate record of the sediment fill. Geomorphic and permafrost studies of lake and river terrace stratigraphies contribute to our understanding of climate dependent landscape evolution. A 16 m long sediment core from the central part of the lake presumably extents the existing record towards more than 400 ka BP. The matching of proxies from this core and the core recovered in 1998 illustrates the lateral continuity of

  9. The redshift evolution of clustering in the Hubble Deep Field

    NASA Astrophysics Data System (ADS)

    Magliocchetti, M.; Maddox, S. J.

    1999-07-01

    We present a correlation function analysis for the catalogue of photometric redshifts obtained from the Hubble Deep Field image by Fernandez-Soto, Lanzetta & Yahil. By dividing the catalogue into redshift bins of width Deltaz=0.4 we measured the angular correlation function w(theta) as a function of redshift up to z~4.8. From these measurements we derive the trend of the correlation length r_0. We find that r_0(z) is roughly constant with look-back time up to z~=2, and then increases to higher values at z>~2.4. We estimate the values of r_0, assuming xi(r,z)=[rr_0(z)]^-gamma, gamma=1.8 and various geometries. For Omega_0=1 we find r_0(z=3)~=7.00+/-4.87h^-1Mpc, in good agreement with the values obtained from analysis of the Lyman break galaxies.

  10. Unsteady evolution of localized unidirectional deep-water wave groups

    NASA Astrophysics Data System (ADS)

    Cousins, Will; Sapsis, Themistoklis P.

    2015-06-01

    We study the evolution of localized wave groups in unidirectional water wave envelope equations [the nonlinear Schrödinger (NLSE) and the modified NLSE (MNLSE)]. These localizations of energy can lead to disastrous extreme responses (rogue waves). We analytically quantify the role of such spatial localization, introducing a technique to reduce the underlying partial differential equation dynamics to a simple ordinary differential equation for the wave packet amplitude. We use this reduced model to show how the scale-invariant symmetries of the NLSE break down when the additional terms in the MNLSE are included, inducing a critical scale for the occurrence of extreme waves.

  11. Deep 20-GHz survey of the Chandra Deep Field South and SDSS Stripe 82: source catalogue and spectral properties

    NASA Astrophysics Data System (ADS)

    Franzen, Thomas M. O.; Sadler, Elaine M.; Chhetri, Rajan; Ekers, Ronald D.; Mahony, Elizabeth K.; Murphy, Tara; Norris, Ray P.; Waldram, Elizabeth M.; Whittam, Imogen H.

    2014-04-01

    We present a source catalogue and first results from a deep, blind radio survey carried out at 20 GHz with the Australia Telescope Compact Array, with follow-up observations at 5.5, 9 and 18 GHz. The Australia Telescope 20 GHz (AT20G) deep pilot survey covers a total area of 5 deg2 in the Chandra Deep Field South and in Stripe 82 of the Sloan Digital Sky Survey. We estimate the survey to be 90 per cent complete above 2.5 mJy. Of the 85 sources detected, 55 per cent have steep spectra (α _{1.4}^{20} < -0.5) and 45 per cent have flat or inverted spectra (α _{1.4}^{20} ≥ -0.5). The steep-spectrum sources tend to have single power-law spectra between 1.4 and 18 GHz, while the spectral indices of the flat- or inverted-spectrum sources tend to steepen with frequency. Among the 18 inverted-spectrum (α _{1.4}^{20} ≥ 0.0) sources, 10 have clearly defined peaks in their spectra with α _{1.4}^{5.5} > 0.15 and α 9^{18} < -0.15. On a 3-yr time-scale, at least 10 sources varied by more than 15 per cent at 20 GHz, showing that variability is still common at the low flux densities probed by the AT20G-deep pilot survey. We find a strong and puzzling shift in the typical spectral index of the 15-20-GHz source population when combining data from the AT20G, Ninth Cambridge and Tenth Cambridge surveys: there is a shift towards a steeper-spectrum population when going from ˜1 Jy to ˜5 mJy, which is followed by a shift back towards a flatter-spectrum population below ˜5 mJy. The 5-GHz source-count model by Jackson & Wall, which only includes contributions from FRI and FRII sources, and star-forming galaxies, does not reproduce the observed flattening of the flat-spectrum counts below ˜5 mJy. It is therefore possible that another population of sources is contributing to this effect.

  12. A sub-millimetre survey of dust enshrouded galaxies in the Hubble Deep Field region

    NASA Astrophysics Data System (ADS)

    Borys, Colin James Kelvin

    This thesis investigates the emission of sub-millimetre- wave radiation from galaxies in the Hubble Deep Field North region. The data were obtained from dedicated observing runs from our group and others using the SCUBA camera on the James Clerk Maxwell Telescope. The data were combined using techniques specifically developed here for low signal-to-noise source recovery. The sources found represent over 10% of all cosmological sources SCUBA has detected since it was commissioned. The number of sub-mm galaxies we detect account for a significant fraction of the sub-mm back-ground, and we show that mild extrapolations can reproduce it entirely. We comment on their clustering properties, both with themselves and other high-redshift galaxy types. A multi-wavelength analysis of these galaxies shows that SCUBA sources do not all have similar properties, and are made of a collection including: star-forming radio galaxies; optically invisible objects; active galactic nuclei; and extremely red objects. Reasonable attempts to determine the redshift distribution of the sample show that SCUBA galaxies have a median redshift of around 2, and suggest that the global star formation rate may be dominated by such objects at redshifts beyond about 1. The thesis summarises the current state of extra-galactic sub-mm astronomy, and comments on how new surveys and detectors will allow us to place stronger constraints on the evolution properties of the high-redshift Universe.

  13. In Brief: Evolution teacher survey; Effects of drought on rainforest

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2005-05-01

    More than 30% of teachers responding to an informal survey indicated that they feel pressured to include creationism, intelligent design, or other nonscientific alternatives to evolution in their science classrooms. An experiment to simulate the effects of climate change and severe drought on a parcel of rainforest in the Brazilian Amazon has found that some parts of the affected forest tolerated the dry condition by absorbing water from deeper in the soil.

  14. Age and evolution of deep continental roots beneath northern Canada

    NASA Astrophysics Data System (ADS)

    Liu, J.; Riches, A. J.; Brin, L.; Pearson, G. D.; Kjarsgaard, B. A.; Stachel, T.; Armstrong, J. P.

    2014-12-01

    The age, composition and extent of Archean lithosphere is well documented beneath the Slave Craton, however, little is known about the deep continental roots beneath the rest of Canada's vast north, despite the discovery of many new diamond-bearing kimberlites. Here we present age and composition information for kimberlite-borne peridotite xenoliths from the western Rae Craton (two localities: Repulse Bay and Pelly Bay) and central Victoria Island (CVI - a possible northern extension of the Slave Craton), as well as the Parry Peninsula (a possible new micro-craton). The peridotites from the western Rae Craton, CVI and Parry Peninsula are generally characterized by high forsterite contents (Fo 92-93) and low whole-rock Al2O3 contents (< 2 wt.%, many < 1wt.%), similar to typical cratonic peridotites worldwide. However, these peridotites show a large span in Re-depletion model ages (TRD). For the western Rae Craton, both localities preserve evidence of Archean parentage, with more of the Repulse Bay samples yielding Archean TRD ages (>2.5 Ga) than for Pelly Bay. The samples from these two localities with post-Archean TRD ages indicate significant lithospheric disturbance likely related to the Arrowsmith Orogeny (ca. 2.3 to 2.5 Ga), contrasting with the little disturbed central Slave lithosphere by other studies. For both CVI and Parry Peninsula peridotites, despite whole-rock and mineralogical compositions analogous to previously studied portions of cratonic mantle, there is no evidence of any Archean TRD ages. Given that the CVI peridotites have major modes in TRD ages of 1.7 to 2.1 Ga, the local lithosphere is more likely to represent an extension of the Wopmay Orogen (ca. 1.9 Ga) to the southwest or the Thelon tectonic-magmatic zone to the east, instead of the northern extension of the Slave Craton. Similarly, TRD ages of 1.8 to 2.3 Ga indicate that the highly depleted Parry Peninsula peridotites are also synchronous with formation of the Wopmay Orogen with a

  15. Geologic evolution of the Bering Sea Komandorksy deep basin

    SciTech Connect

    Bogdanov, N.A.

    1986-07-01

    The deep-water Komandorsky basin is located in the southwestern part of the Bering Sea. On the east, it is separated from the Aleutian basin by the submerged Shirshov Ridge; on the west, it is bordered by structures of the north Kamchatka accretionary prism. The Komandorsky basin is characterized by strongly dissected relief of it acoustic basement, which is overlain by a 1.5 to 2.0-km thick sedimentary cover. The western part of the basin is occupied by a rift zone, which is characterized by modern seismicity and high heat flow. It is considered to be the axial zone of Miocene-Pleistocene spreading. On the north terrace of the Komandorsky island arc, traced active volcanos provide evidence that subduction is occurring under the arc from the north. The spreading rift zone is reflected on the continent in Miocene-Pleistocene volcanic rocks, characterized by typical oceanic tholeiitic composition. The Komandorsky basin formed as a result of spreading during the Maestrichtian. Spreading within the basin occurred during the early and middle Oligocene and the late Miocene. East and west of the spreading axis, accretionary prisms formed. The latter are observed along the western flank of the Shirshov Ridge and on the eastern sides of the Kamchatka Peninsula and Koraginsky Island.

  16. The Origin and Evolution of Deep Plasmaspheric Notches

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Adrian, M. L.; Liemohn, M.

    2004-01-01

    Deep plasmaspheric notches can extend over more than 2 RE in radial distance and 3 hours MLT in the magnetic equatorial plane. They appear to be among the largest evacuated features in the exterior plasmaspheric boundary. They can last for days and exhibit varying structure. It appears that low-density channels resulting from the entrainment of the plasmaspheric convection plume during storm-time recovery share the same origin as notches. Notches rather than channels result from differences in storm- time conditions. Strong convection tends to result in low-density channels, while weaker convection and limited erosion results in notches. Eighteen events in 2000 have been analyzed. Among these events, notches were found to drift as slowly as 72% of corotation. In only one case was a notch found to drift at the corotation rate within measurement error. On average, notches drift at about 2 1.5 hours per day or 90% of the co-rotational rate. Notches also sometimes exhibit an interior structure that appears as an extended prominence of dense plasma, which forms a W-like feature in IMAGEEUV images when viewed from Earth-center. Modeling suggests such features may be caused by small-scale potential structures that result from the localized injection of ring current plasma. Plasma filling rates during recovery and drainage during a minor storm are reported.

  17. The UKIRT Infrared Deep Sky Survey (UKIDSS): Origins and Highlights

    NASA Astrophysics Data System (ADS)

    Lawrence, Andy

    UKIDSS is now roughly half finished, covering several thousand square degrees, and expected to complete by the middle of 2012. So far 13.5 billion rows of data have been downloaded by several hundred users, resulting in 154 publications concerning high-z quasars, the nearest and coolest brown dwarfs, the evolution of galaxies, the sub-stellar mass function, and many other topics. I summarise the origins and status of UKIDSS, and briefly describe some scientific highlights.

  18. SCORPIO: a deep survey of radio emission from the stellar life-cycle

    NASA Astrophysics Data System (ADS)

    Umana, G.; Trigilio, C.; Franzen, T. M. O.; Norris, R. P.; Leto, P.; Ingallinera, A.; Buemi, C. S.; Agliozzo, C.; Cavallaro, F.; Cerrigone, L.

    2015-11-01

    Radio emission has been detected in a broad variety of stellar objects from all stages of stellar evolution. However, most of our knowledge originates from targeted observations of small samples, which are strongly biased to sources which are peculiar at other wavelengths. In order to tackle this problem we have conducted a deep 1.4 GHz survey by using the Australian Telescope Compact Array, with a net bandwidth of 1.7 GHz (1.4-3.1 GHz) , following the same observing setup as that used for the Australia Telescope Large Area Survey project, this time choosing a region more appropriate for stellar work. In this paper, the Stellar Continuum Originating from Radio Physics In Ourgalaxy (SCORPIO) project is presented as well as results from the pilot experiment. The achieved rms is 30 μJy and the angular resolution ˜10 arcsec. 614 point-like sources have been extracted just from the pilot field. Only 34 of them are classified in SIMBAD or the NASA/IPAC Extragalactic Database. About 80 per cent of the extracted sources are reported in one of the inspected catalogues and 50 per cent of them appears to belong to a reddened stellar/Galactic population. However, the evaluation of extragalactic contaminants is very difficult without further investigations. Interesting results have been obtained for extended radio sources that fall in the SCORPIO field. Many roundish-like structures (indicated as bubbles in the following) have been found, some of which are classified at other wavelengths. However, for all of these sources, our project has provided us with images of unprecedented sensitivity and angular resolution.

  19. The Ejecta Evolution of Deep Impact: Insight from Experiments

    NASA Astrophysics Data System (ADS)

    Hermalyn, B.; Schultz, P. H.; Heineck, J. T.

    2010-12-01

    The Deep Impact (DI) probe impacted comet 9P/Tempel 1 at an angle of ~30° from local horizontal with a velocity of 10.2 km/s. Examination of the resulting ballistic (e.g., non-vapor driven) ejecta revealed phenomena that largely followed expectations from laboratory investigations of oblique impacts into low-density porous material, including a downrange bias, uprange zone of avoidance, and cardioid (curved) rays (Schultz, et al, 2005, 2007). Modeling of the impact based on canonical models and scaling laws (Richardson, et al, 2007) allowed a first-order reconstruction of the event, but did not fully represent the three-dimensional nature of the ejecta flow-field in an oblique impact essential for interpretation of the DI data. In this study, we present new experimental measurements of the early-time ejecta dynamics in oblique impacts that allow a more complete reconstruction of the ballistic ejecta from the impact, including visualization of the DI encounter and predictions for the upcoming re-encounter with Tempel 1. A suite of hypervelocity 30° impact experiments into granular materials was performed at the NASA Ames Vertical Gun Range (AVGR) for the purpose of interpreting the Deep Impact event. A technique based on Particle Tracking Velocimetry (PTV) permitted non-intrusive measurement of the ejecta velocity within the ejecta curtain. The PTV system developed at the AVGR utilizes a laser light sheet projected parallel to the impact surface to illuminate horizontal “slices” of the ejecta curtain that are then recorded by multiple cameras. Particle displacement between successive frames and cameras allows determination of the three-component velocity of the ejecta curtain. Pioneering efforts with a similar technique (Anderson, et al, 2003, 2006) characterized the main-stage ejecta velocity distributions and demonstrated that asymmetries in velocity and ejection angle persist well into the far-field for oblique impacts. In this study, high-speed cameras

  20. Galaxy evolution at high-redshift: Millimeter-wavelength surveys with the AzTEC camera

    NASA Astrophysics Data System (ADS)

    Scott, Kimberly S.

    Galaxies detected by their thermal dust emission at submillimeter (submm) and millimeter (mm) wavelengths comprise a population of massive, intensely star-forming systems in the early Universe. These "submm/mm- galaxies", or SMGs, likely represent an important phase in the assembly and/or evolution of massive galaxies and are thought to be the progenitors of massive elliptical galaxies. While their projected number density as a function of source brightness provides key constraints on models of galaxy evolution, SMG surveys carried out over the past twelve years with the first generation of submm/mm-wavelength cameras have not imaged a large enough area to sufficient depths to provide the statistical power needed to discriminate between competing galaxy evolution scenarios. In this dissertation, we present the results from SMG surveys carried out over the past four years using the new sensitive mm-wavelength camera AzTEC. With the improved mapping speed of the AzTEC camera combined with dedicated telescope time devoted to deep, large-area extragalactic surveys, we have tripled both the area surveyed towards blank- fields (that is, regions with no known galaxy over-densities) at submm/mm wavelengths and the total number of detected SMGs. Here, we describe the properties and performance of the AzTEC instrument while operating on the James Clerk Maxwell Telescope (JCMT) and the Atacama Submillimeter Telescope Experiment (ASTE). We then present the results from two of the blank-field regions imaged with AzTEC: the JCMT/COSMOS field, which we discovered is over- dense in the number of very bright SMGs, and the ASTE survey of the Great Observatories Origins Deep-South field, which represents one of the deepest surveys ever carried out at submm/mm wavelengths. Finally, we combine the results from all of the blank-fields imaged with AzTEC while operating on the JCMT and the ASTE to calculate the most accurate measurements to date of the SMG number counts.

  1. The SuperCLASS Weak Lensing Deep Field Survey

    NASA Astrophysics Data System (ADS)

    Harrison, Ian; Superclass Collaboration

    2014-04-01

    SuperCLASS is a survey of 1.75 square degrees of the Northern sky using the e-MERLIN telescope array at a frequency of 1.4GHz, aiming to reach an image noise RMS level of 4 micro-Jy/beam. The primary goal is to use the expected source density of ~1 per square arcminute (giving a total of ~10,000), ~150 milli-arcsecond resolution and presence in the survey region of 5 massive Abell clusters to measure a significant weak lensing effect in the radio band for only the second time, proving the potential of radio weak lensing as a powerful tool for mapping dark matter and constraining cosmological models. In doing this we will also learn a significant amount about the source population (star forming galaxies and radio AGN) themselves and their polarisation properties. SuperCLASS will not only require development of a pipeline for making the highly accurate determination of shapes of a large number of sources for performing standard weak lensing measurements, but will also form a test bed for new methods, such as the use of polarisation information to mitigate the biasing effect of intrinsic alignments between galaxies, which will be a key systematic for future weak lensing surveys. Whilst the challenges of the necessary shape measurement in image plane optical data are relatively well-explored, there is little experience in meeting those involved in the use of data from radio interferometers. The knowledge gained about efficient and accurate techniques for large scale radio astronomy from SuperCLASS will be invaluable in the build up to the next generation of experiments.

  2. A Deep Chandra ACIS Survey of M51

    NASA Astrophysics Data System (ADS)

    Kuntz, K. D.; Long, Knox S.; Kilgard, Roy E.

    2016-08-01

    We have obtained a deep X-ray image of the nearby galaxy M51 using Chandra. Here we present the catalog of X-ray sources detected in these observations and provide an overview of the properties of the point-source population. We find 298 sources within the D 25 radii of NGC 5194/5, of which 20% are variable, a dozen are classical transients, and another half dozen are transient-like sources. The typical number of active ultraluminous X-ray sources in any given observation is ˜5, and only two of those sources persist in an ultraluminous state over the 12 yr of observations. Given reasonable assumptions about the supernova remnant population, the luminosity function is well described by a power law with an index between 1.55 and 1.7, only slightly shallower than that found for populations dominated by high-mass X-ray binaries (HMXBs), which suggests that the binary population in NGC 5194 is also dominated by HMXBs. The luminosity function of NGC 5195 is more consistent with a low-mass X-ray binary dominated population. Based on observations made with NASA's Chandra X-ray Observatory, which is operated by the Smithsonian Astrophysical Observatory under contract #NAS83060, and the data were obtained through program GO1-12115.

  3. A Deep Chandra ACIS Survey of M51

    NASA Astrophysics Data System (ADS)

    Kuntz, K. D.; Long, Knox S.; Kilgard, Roy E.

    2016-08-01

    We have obtained a deep X-ray image of the nearby galaxy M51 using Chandra. Here we present the catalog of X-ray sources detected in these observations and provide an overview of the properties of the point-source population. We find 298 sources within the D 25 radii of NGC 5194/5, of which 20% are variable, a dozen are classical transients, and another half dozen are transient-like sources. The typical number of active ultraluminous X-ray sources in any given observation is ∼5, and only two of those sources persist in an ultraluminous state over the 12 yr of observations. Given reasonable assumptions about the supernova remnant population, the luminosity function is well described by a power law with an index between 1.55 and 1.7, only slightly shallower than that found for populations dominated by high-mass X-ray binaries (HMXBs), which suggests that the binary population in NGC 5194 is also dominated by HMXBs. The luminosity function of NGC 5195 is more consistent with a low-mass X-ray binary dominated population. Based on observations made with NASA's Chandra X-ray Observatory, which is operated by the Smithsonian Astrophysical Observatory under contract #NAS83060, and the data were obtained through program GO1-12115.

  4. Radio variability in the Phoenix Deep Survey at 1.4 GHz

    NASA Astrophysics Data System (ADS)

    Hancock, P. J.; Drury, J. A.; Bell, M. E.; Murphy, T.; Gaensler, B. M.

    2016-09-01

    We use archival data from the Phoenix Deep Survey to investigate the variable radio source population above 1 mJy beam-1 at 1.4 GHz. Given the similarity of this survey to other such surveys we take the opportunity to investigate the conflicting results which have appeared in the literature. Two previous surveys for variability conducted with the Very Large Array (VLA) achieved a sensitivity of 1 mJy beam-1. However, one survey found an areal density of radio variables on time-scales of decades that is a factor of ˜4 times greater than a second survey which was conducted on time-scales of less than a few years. In the Phoenix deep field we measure the density of variable radio sources to be ρ = 0.98 deg-2 on time-scales of 6 months to 8 yr. We make use of Wide-field Infrared Survey Explorer infrared cross-ids, and identify all variable sources as an active galactic nucleus of some description. We suggest that the discrepancy between previous VLA results is due to the different time-scales probed by each of the surveys, and that radio variability at 1.4 GHz is greatest on time-scales of 2-5 yr.

  5. A Deep Imaging Survey of NGC 6475 and a Deep Survey of the Young Open Cluster Alpha Persei

    NASA Technical Reports Server (NTRS)

    Stauffer, John R.

    1997-01-01

    We have published three papers directly related to the x-ray data (see below), and one other paper directly related to the optical photometry obtained in connection to the ROSAT data analysis (also listed below). In addition, we have used the x-ray data in combination with the optical photometry and with high resolution optical spectra that we have obtained (to derive spectroscopic rotational velocities) to address questions related to the dependence of coronal activity on the rotation rate, mass, and other characteristics of the target stars. The overall goal of our ROSAT projects has been to determine the time evolution of coronal activity in low mass stars, and from that behavior place constraints on the physical processes involved in generating coronal activity. NGC 6475 and Alpha Persei are important parts of that process. We are now beginning to address how these data constrain theoretical models of angular momentum evolution and dynamo magnetic field generation (see paper by Stauffer et al. and Krishnamurthi et al. listed below in the "related papers" section). We are still working on two papers pertaining to this grant (rotational velocities and chromospheric activity of Alpha Persei x-ray sources and rotational velocities and lithium abundances of NGC 6475 sources), but we will publish those papers using funds from other grants.

  6. Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- GOODS-North Field, Late Visits of SNe Search

    NASA Astrophysics Data System (ADS)

    Faber, Sandra

    2012-10-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey {CANDELS}is designed to document the |*|rst third of galactic evolution from z =8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IRand ACS. It will also find the first Type Ia SNe beyond z > 1.5 andestablish their accuracy as standard candles for cosmology. Fivepremier multi-wavelength sky regions selected from the SpitzerExtragalactic Deep Survey {SEDS} provide complementary IRAC imagingdata down to 26.5 AB mag, a unique resource for stellar masses at allredshifts. The use of |*|ve widely separated |*|elds mitigates cosmicvariance and yields statistically robust and complete samples ofgalaxies down to 10^9 solar masses out to z 8.The program merges two originally separate MCT proposals. The Faberprogram incorporates a |*|Wide|*| imaging survey in three separate fieldsto 2 orbit depth over 0.2 sq. degrees, plus a |*|Deep|*| imaging surveyto 12 orbit depth in the two GOODS regions over 0.04 sq. degrees.When combined with ultra-deep imaging from the Hubble Ultradeep Fieldprogram {GO 11563}, the result is a three-tiered strategy that ef|*|cientlysamples both bright/rare and faint/common extragalactic objects. TheFerguson program adds an extensive high-redshift Type Ia SNe search,plus ultraviolet "daytime" UVIS exposures in GOODS-N to exploit theCVZ opportunity in that field.This program, GO 12060, is part of the GOODS-S Deep survey. Special Deepscience highlights include: * Detection and counts of early galaxies to z 7-8 as revealed by red-sensitive WFC3-IR images beyond the Lya break - Measurement of the luminosity function of infant galaxies down to 10^9 solar masses out to z = 7-8 - Measurement of the faint-end LF slope to assess the contribution of faint galaxies to cosmic reionization * The physics of early star formation - Propertes of the earliest star-forming regions - sizes, star-formation rates, stellar masses and radiation densities, dust contents - In concert with Spitzer

  7. A Deep Submillimeter Survey of the Galactic Center

    NASA Astrophysics Data System (ADS)

    Pierce-Price, D.; Richer, J. S.; Greaves, J. S.; Holland, W. S.; Jenness, T.; Lasenby, A. N.; White, G. J.; Matthews, H. E.; Ward-Thompson, D.; Dent, W. R. F.; Zylka, R.; Mezger, P.; Hasegawa, T.; Oka, T.; Omont, A.; Gilmore, G.

    2000-12-01

    We present first results from a submillimeter continuum survey of the Galactic center ``central molecular zone'' (CMZ), made with the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope. SCUBA's scan-map mode has allowed us to make extremely wide field maps of thermal dust emission with unprecedented speed and sensitivity. We also discuss some issues related to the elimination of artifacts in scan-map data. Our simultaneous 850/450 μm maps have a total size of approximately 2.8d×0.5d (400×75 pc) elongated along the Galactic plane. They cover the Sagittarius A region, including Sgr A*, the circumnuclear disk, and the 20 and 50 km s-1 clouds; the area around the Pistol; Sgr B2, the brightest feature on the maps; and at their Galactic western and eastern edges the Sgr C and Sgr D regions. There are many striking features such as filaments and shell-like structures as well as point sources such as Sgr A* itself. The total mass in the CMZ is greater than that revealed in previous optically thin molecular line maps by a factor of ~3, and new details are revealed on scales down to 0.33 pc across this 400 pc-wide region.

  8. The NOAO Deep Wide-Field Survey Image Cutout Web Service

    NASA Astrophysics Data System (ADS)

    Davis, Lindsey E.; Fitzpatrick, Mike; Tody, Doug

    A Web service for extracting multi-band science grade image cutouts from the NOAO Deep Wide-Field Survey (NDWFS) is described. The NDWFS data is stored as a multi-band database of large images on the NDWFS archive server. Given a cutout center and size the NDWFS image cutout service creates cutout images on-the-fly. The service provides high performance access to the survey data and isolates the client from the details of how the survey data is stored in the archive.

  9. Multiparametrical survey to understand the dynamic of monitored deep seated Landslide (La Clapière DSL)

    NASA Astrophysics Data System (ADS)

    Palis, Edouard; Lebourg, Thomas; Vidal, Maurin; Vitard, Clement; Tric, Emmanuel

    2014-05-01

    The geology and the structure of a deep seated landslide (La Clapiere with 65 million m3, south eastern France) explains the complex hydrology of the site which plays a key-role in the destabilization and the multiphase dynamics of the slope (water circulation within the sliding mass, fluid exchanges between superficial and deep layers aquifer through faults). To understand fluid circulations within the unstable slope, a pluri-annual multi parametric survey was set up, but since 18 months the survey combines new research multiparametric station. The landslide (La Clapiere) is located in the Argentera-Mercantour massif, and it has been instrumented since 1982 by academic researchers and since 2003 by the Multidisciplinary Observatory of Versant Instabilities (OMIV, the French National Observation Service (SNO)). A permanent electrical tomography monitoring was installed on the landslide since November 2012 to complement the actual monitoring system (GPS, seismic, pluviometric and hydrogeologic data). The aim of this study is to analyze the temporal evolution of resistivity, positioning and pluviometry during the November 2012 to March 2013 period. A qualitative and statistical approach by clustering, principal component analysis (PCA), and probability density function (Pdf) of resistivity data, coupled with pluviometric and GPS data provides a better understanding of the dynamics in this place. Rainfall induces strong accelerations of the rockslide movement. This new statistical study also explained the major roles of the fault and the basement of the landslide, and the time chronology of the water flow in the massif.

  10. The WIRCam Deep Survey. I. Counts, colours, and mass-functions derived from near-infrared imaging in the CFHTLS deep fields

    NASA Astrophysics Data System (ADS)

    Bielby, R.; Hudelot, P.; McCracken, H. J.; Ilbert, O.; Daddi, E.; Le Fèvre, O.; Gonzalez-Perez, V.; Kneib, J.-P.; Marmo, C.; Mellier, Y.; Salvato, M.; Sanders, D. B.; Willott, C. J.

    2012-09-01

    We present a new near-infrared imaging survey in the four CFHTLS deep fields: the WIRCam Deep Survey or "WIRDS". WIRDS comprises extremely deep, high quality (FWHM ~ 0.6″) J, H, and Ks imaging covering a total effective area of 2.1 deg2 and reaching AB 50% completeness limits of ≈ 24.5. We combine our images with the CFHTLS to create a unique eight-band ugrizJHKS photometric catalogues in the four CFHTLS deep fields; these four separate fields allow us to make a robust estimate of the effect of cosmic variance for all our measurements. We use these catalogues in combination with ≈ 9800 spectroscopic redshifts to estimate precise photometric redshifts (σΔz/(1 + z) ≲ 0.03 at i < 25), galaxy types, star-formation rates and stellar masses for a unique sample of ≈ 1.8 million galaxies. Our JHKs number counts are consistent with previous studies. We apply the "BzK" selection to our gzK filter set and find that the star forming BzK selection successfully selects 76% of star-forming galaxies in the redshift range 1.4 < z < 2.5 in our photometric catalogue, based on our photometric redshift measurement. Similarly the passive BzK selection returns 52% of the passive 1.4 < z < 2.5 population identified in the photometric catalogue. We present the mass functions of the total galaxy population as a function of redshift up to z = 2 and present fits using double Schechter functions. A mass-dependent evolution of the mass function is seen with the numbers of galaxies with masses of M ≲ 1010.75 still evolving at z ≲ 1, but galaxies of higher mass reaching their present day numbers by z ~ 0.8-1. This is consistent with the present picture of downsizing in galaxy evolution. We compare our results with the predictions of the GALFORM semi-analytical galaxy formation model and find that the simulations provide a relatively successful fit to the observed mass functions at intermediate masses (i.e. 10 ≲ log (M/M⊙) ≲ 11). However, as is common with semi

  11. Bright z ~ 3 Lyman break galaxies in deep wide field surveys

    NASA Astrophysics Data System (ADS)

    Bian, Fuyan

    In my thesis I investigate the luminous z ˜ 3 Lyman break galaxies in deep wide field surveys. In the first part of the thesis, I use the LBT/LUCIFER to observe a lensed high-redshift star-forming galaxy (J0900+2234) at z = 2.03. With the high S/N near-IR spectroscopic observations, I reveal the detailed physical properties of this high-redshift galaxy, including SFR, metallicity, dust extinction, dynamical mass, and electron number density. In the second part of the thesis, I select a large sample of LBGs at z ˜ 3 from our new LBT Bootes field survey, and study the bright end luminosity function (LF), stellar mass function (SMF) and clustering properties of bright LBGs (1L* < L < 2.5L*). Together with other LF and SMF measurements, the evolution of LF and SMF can be well described by continuously rising star formation history model. Using the clustering measurements in this work and other works, a tight relation between the average host galaxy halo mass and the galaxy star formation rate is found, which can be interpreted as arising from cold flow accretion. The relation also suggests that the cosmic star formation efficiency is about 5%-20% of the total cold flow mass. This cosmic star formation efficiency does not evolve with redshift (from z ˜ 5 to z ˜ 3), hosting dark matter halo mass (1011 -- 1013 M⊙ ), or galaxy luminosity (from 0.3L* to 3L* ). In the third and fourth parts, with the spectroscopic follow-up observations of the bright LBGs, I establish a sample of spectroscopically-confirmed ultraluminous LBGs (ULBGs) in NOAO Boo¨tes field. With this new ULBG sample, the rest-frame UV LF of LBG at M1700A = -23.0 was measured for the first time. I find that the ULBGs have larger outflow velocity, broader Lyalpha emission and ISM absorption line profiles, and more prominent C IV P-Cygni profile. This profile may imply a top-heavy IMF in these ULBGs. The ULBGs have larger stellar mass and SFR, but smaller dust extinction than the typical L* LBGs at z ˜ 2

  12. First results from the Bulge Asymmetries and Dynamic Evolution survey

    NASA Astrophysics Data System (ADS)

    Pihlstrom, Ylva; Sjouwerman, Lorant; Rich, Robert Michael; Claussen, Mark J.; Morris, Mark; BAaDE Collaboration

    2016-01-01

    The goal of the Bulge Asymmetries and Dynamic Evolution (BAaDE) project is to undertake the largest ever survey of red giant SiO maser sources (~20,000) in the bulge and inner Galaxy. This survey will provide a confusion-free, extinction-free, densely sampled set of point-masses in the regions of the Galaxy that are not reachable with optical surveys (concentrated along 0°

  13. The ALHAMBRA Survey: Evolution of Galaxy Spectral Segregation

    NASA Astrophysics Data System (ADS)

    Hurtado-Gil, Ll.; Arnalte-Mur, P.; Martínez, V. J.; Fernández-Soto, A.; Stefanon, M.; Ascaso, B.; López-Sanjuán, C.; Márquez, I.; Pović, M.; Viironen, K.; Aguerri, J. A. L.; Alfaro, E.; Aparicio-Villegas, T.; Benítez, N.; Broadhurst, T.; Cabrera-Caño, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; Cristóbal-Hornillos, D.; González Delgado, R. M.; Husillos, C.; Infante, L.; Masegosa, J.; Moles, M.; Molino, A.; del Olmo, A.; Paredes, S.; Perea, J.; Prada, F.; Quintana, J. M.

    2016-02-01

    We study the clustering of galaxies as a function of spectral type and redshift in the range 0.35 < z < 1.1 using data from the Advanced Large Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) survey. The data cover 2.381 deg2 in 7 fields, after applying a detailed angular selection mask, with accurate photometric redshifts {{[}}{σ }z\\lt 0.014(1+z){{]}} down to IAB < 24. From this catalog we draw five fixed number density redshift-limited bins. We estimate the clustering evolution for two different spectral populations selected using the ALHAMBRA-based photometric templates: quiescent and star-forming galaxies. For each sample we measure the real-space clustering using the projected correlation function. Our calculations are performed over the range [0.03, 10.0] h-1 Mpc, allowing us to find a steeper trend for {r}p≲ 0.2 {h}-1 Mpc, which is especially clear for star-forming galaxies. Our analysis also shows a clear early differentiation in the clustering properties of both populations: star-forming galaxies show weaker clustering with evolution in the correlation length over the analyzed redshift range, while quiescent galaxies show stronger clustering already at high redshifts and no appreciable evolution. We also perform the bias calculation where similar segregation is found, but now it is among the quiescent galaxies where a growing evolution with redshift is clearer (abrigatted). These findings clearly corroborate the well-known color-density relation, confirming that quiescent galaxies are mainly located in dark matter halos that are more massive than those typically populated by star-forming galaxies.

  14. Evolution of Balmer jump selected galaxies in the ALHAMBRA survey

    NASA Astrophysics Data System (ADS)

    Troncoso Iribarren, P.; Infante, L.; Padilla, N.; Lacerna, I.; Garcia, S.; Orsi, A.; Muñoz Arancibia, A.; Moustakas, J.; Cristóbal-Hornillos, D.; Moles, M.; Fernández-Soto, A.; Martínez, V. J.; Cerviño, M.; Alfaro, E. J.; Ascaso, B.; Arnalte-Mur, P.; Nieves-Seoane, L.; Benítez, N.

    2016-04-01

    Context. Samples of star-forming galaxies at different redshifts have been traditionally selected via color techniques. The ALHAMBRA survey was designed to perform a uniform cosmic tomography of the Universe, and we here exploit it to trace the evolution of these galaxies. Aims: Our objective is to use the homogeneous optical coverage of the ALHAMBRA filter system to select samples of star-forming galaxies at different epochs of the Universe and study their properties. Methods: We present a new color-selection technique, based on the models of spectral evolution convolved with the ALHAMBRA bands and the redshifted position of the Balmer jump to select star-forming galaxies in the redshift range 0.5 evolution of an evolving population of halos as they grow to reach a mass of ~1012.7 ± 0.1 at z = 0.5. The likely progenitors of our samples at z ~ 3 are Lyman-break galaxies, which at z ~ 2 would evolve into star-forming BzK galaxies, and their descendants in the local Universe are galaxies with luminosities of 1-3 L∗. Hence, this allows us to follow the putative evolution of the SFR, stellar mass, and age of these galaxies. Conclusions: From z ~ 1.0 to z ~ 0.5, the stellar mass of the volume-limited BJG samples changes almost not at all with redshift, suggesting that major mergers play a minor role in the evolution of these galaxies. The SFR evolution accounts for the small

  15. The DEEP2 Galaxy Redshift Survey: Design, Observations, Data Reduction, and Redshifts

    NASA Technical Reports Server (NTRS)

    Newman, Jeffrey A.; Cooper, Michael C.; Davis, Marc; Faber, S. M.; Coil, Alison L; Guhathakurta, Puraga; Koo, David C.; Phillips, Andrew C.; Conroy, Charlie; Dutton, Aaron A.; Finkbeiner, Douglas P.; Gerke, Brian F.; Rosario, David J.; Weiner, Benjamin J.; Wilmer, C. N. A.; Yan, Renbin; Harker, Justin J.; Kassin, Susan A.; Konidaris, N. P.; Lai, Kamson; Madgwick, Darren S.; Noeske, K. G.; Wirth, Gregory D.; Kirby, Evan N.; Lotz, Jennifer M.

    2013-01-01

    We describe the design and data analysis of the DEEP2 Galaxy Redshift Survey, the densest and largest high-precision redshift survey of galaxies at z approx. 1 completed to date. The survey was designed to conduct a comprehensive census of massive galaxies, their properties, environments, and large-scale structure down to absolute magnitude MB = -20 at z approx. 1 via approx.90 nights of observation on the Keck telescope. The survey covers an area of 2.8 Sq. deg divided into four separate fields observed to a limiting apparent magnitude of R(sub AB) = 24.1. Objects with z approx. < 0.7 are readily identifiable using BRI photometry and rejected in three of the four DEEP2 fields, allowing galaxies with z > 0.7 to be targeted approx. 2.5 times more efficiently than in a purely magnitude-limited sample. Approximately 60% of eligible targets are chosen for spectroscopy, yielding nearly 53,000 spectra and more than 38,000 reliable redshift measurements. Most of the targets that fail to yield secure redshifts are blue objects that lie beyond z approx. 1.45, where the [O ii] 3727 Ang. doublet lies in the infrared. The DEIMOS 1200 line mm(exp -1) grating used for the survey delivers high spectral resolution (R approx. 6000), accurate and secure redshifts, and unique internal kinematic information. Extensive ancillary data are available in the DEEP2 fields, particularly in the Extended Groth Strip, which has evolved into one of the richest multiwavelength regions on the sky. This paper is intended as a handbook for users of the DEEP2 Data Release 4, which includes all DEEP2 spectra and redshifts, as well as for the DEEP2 DEIMOS data reduction pipelines. Extensive details are provided on object selection, mask design, biases in target selection and redshift measurements, the spec2d two-dimensional data-reduction pipeline, the spec1d automated redshift pipeline, and the zspec visual redshift verification process, along with examples of instrumental signatures or other

  16. The DEEP2 Galaxy Redshift Survey: Design, Observations, Data Reduction, and Redshifts

    NASA Astrophysics Data System (ADS)

    Newman, Jeffrey A.; Cooper, Michael C.; Davis, Marc; Faber, S. M.; Coil, Alison L.; Guhathakurta, Puragra; Koo, David C.; Phillips, Andrew C.; Conroy, Charlie; Dutton, Aaron A.; Finkbeiner, Douglas P.; Gerke, Brian F.; Rosario, David J.; Weiner, Benjamin J.; Willmer, C. N. A.; Yan, Renbin; Harker, Justin J.; Kassin, Susan A.; Konidaris, N. P.; Lai, Kamson; Madgwick, Darren S.; Noeske, K. G.; Wirth, Gregory D.; Connolly, A. J.; Kaiser, N.; Kirby, Evan N.; Lemaux, Brian C.; Lin, Lihwai; Lotz, Jennifer M.; Luppino, G. A.; Marinoni, C.; Matthews, Daniel J.; Metevier, Anne; Schiavon, Ricardo P.

    2013-09-01

    We describe the design and data analysis of the DEEP2 Galaxy Redshift Survey, the densest and largest high-precision redshift survey of galaxies at z ~ 1 completed to date. The survey was designed to conduct a comprehensive census of massive galaxies, their properties, environments, and large-scale structure down to absolute magnitude MB = -20 at z ~ 1 via ~90 nights of observation on the Keck telescope. The survey covers an area of 2.8 deg2 divided into four separate fields observed to a limiting apparent magnitude of R AB = 24.1. Objects with z <~ 0.7 are readily identifiable using BRI photometry and rejected in three of the four DEEP2 fields, allowing galaxies with z > 0.7 to be targeted ~2.5 times more efficiently than in a purely magnitude-limited sample. Approximately 60% of eligible targets are chosen for spectroscopy, yielding nearly 53,000 spectra and more than 38,000 reliable redshift measurements. Most of the targets that fail to yield secure redshifts are blue objects that lie beyond z ~ 1.45, where the [O II] 3727 Å doublet lies in the infrared. The DEIMOS 1200 line mm-1 grating used for the survey delivers high spectral resolution (R ~ 6000), accurate and secure redshifts, and unique internal kinematic information. Extensive ancillary data are available in the DEEP2 fields, particularly in the Extended Groth Strip, which has evolved into one of the richest multiwavelength regions on the sky. This paper is intended as a handbook for users of the DEEP2 Data Release 4, which includes all DEEP2 spectra and redshifts, as well as for the DEEP2 DEIMOS data reduction pipelines. Extensive details are provided on object selection, mask design, biases in target selection and redshift measurements, the spec2d two-dimensional data-reduction pipeline, the spec1d automated redshift pipeline, and the zspec visual redshift verification process, along with examples of instrumental signatures or other artifacts that in some cases remain after data reduction. Redshift

  17. THE DEEP2 GALAXY REDSHIFT SURVEY: DESIGN, OBSERVATIONS, DATA REDUCTION, AND REDSHIFTS

    SciTech Connect

    Newman, Jeffrey A.; Cooper, Michael C.; Davis, Marc; Faber, S. M.; Guhathakurta, Puragra; Koo, David C.; Phillips, Andrew C.; Conroy, Charlie; Harker, Justin J.; Lai, Kamson; Dutton, Aaron A.; Finkbeiner, Douglas P.; Gerke, Brian F.; Rosario, David J.; Weiner, Benjamin J.; Willmer, C. N. A.; Yan Renbin; Kassin, Susan A.; Konidaris, N. P. E-mail: djm70@pitt.edu E-mail: mdavis@berkeley.edu E-mail: koo@ucolick.org E-mail: phillips@ucolick.org; and others

    2013-09-15

    We describe the design and data analysis of the DEEP2 Galaxy Redshift Survey, the densest and largest high-precision redshift survey of galaxies at z {approx} 1 completed to date. The survey was designed to conduct a comprehensive census of massive galaxies, their properties, environments, and large-scale structure down to absolute magnitude M{sub B} = -20 at z {approx} 1 via {approx}90 nights of observation on the Keck telescope. The survey covers an area of 2.8 deg{sup 2} divided into four separate fields observed to a limiting apparent magnitude of R{sub AB} = 24.1. Objects with z {approx}< 0.7 are readily identifiable using BRI photometry and rejected in three of the four DEEP2 fields, allowing galaxies with z > 0.7 to be targeted {approx}2.5 times more efficiently than in a purely magnitude-limited sample. Approximately 60% of eligible targets are chosen for spectroscopy, yielding nearly 53,000 spectra and more than 38,000 reliable redshift measurements. Most of the targets that fail to yield secure redshifts are blue objects that lie beyond z {approx} 1.45, where the [O II] 3727 A doublet lies in the infrared. The DEIMOS 1200 line mm{sup -1} grating used for the survey delivers high spectral resolution (R {approx} 6000), accurate and secure redshifts, and unique internal kinematic information. Extensive ancillary data are available in the DEEP2 fields, particularly in the Extended Groth Strip, which has evolved into one of the richest multiwavelength regions on the sky. This paper is intended as a handbook for users of the DEEP2 Data Release 4, which includes all DEEP2 spectra and redshifts, as well as for the DEEP2 DEIMOS data reduction pipelines. Extensive details are provided on object selection, mask design, biases in target selection and redshift measurements, the spec2d two-dimensional data-reduction pipeline, the spec1d automated redshift pipeline, and the zspec visual redshift verification process, along with examples of instrumental signatures or

  18. Deep 2mm Surveys with GISMO : Searching for submillimeter galaxies at the highest redshifts

    NASA Astrophysics Data System (ADS)

    Staguhn, Johannes Gunter; Kovacs, Attila; Karim, Alexander; Arendt, Richard; Benford, Dominic J.; Decarli, Roberto; Dwek, Eli; Fixsen, Dale; Gene, Hilton; Irwin, Kent; Moseley, S. Harvey; Sharp, Elmer; Walter, Fabian; Edward, Wollack

    2015-08-01

    The GISMO 2 mm camera at the IRAM 30m telescope has been available to the astronomical community for years through the semi-annual IRAM call for proposals. The 2 mm band is in particular well suited to trace the first dusty galaxies in the universe, since their redshifted SEDs peak close to GISMO's observing frequency, whereas the medium redshift galaxy foreground is almost invisible in this band. This effect makes GISMO's deep field observations a valuable complement, rather than a redundancy, to the HERSCHEL far-infrared and sub-mm surveys. Two survey projects aiming at obtaining 2mm galaxy number counts are at the core of GISMO’s science. Simple models predict an appreciable number of galaxies detected in these surveys to be be at very high redshifts (z~5-6 and above) with intrinsic luminosities of a few 10^12 L_sol.The first of these projects is the GISMO Deep Field (GDF) survey, which is centered on the Hubble Deep Field North. This survey by now has reached the confusion limit (we measure a confusion noise of 60 microJy). Our detailed statistical analysis of the GDF data provides a solid estimate of the expected rate of false detections among those source identifications. Furthermore, numerical simulations were used, to estimate the "completeness" of our set of extracted sources. A comparison of our observations with model predictions shows that our results are in good agreement with galaxy count models.The second survey covers a ~ 1/4 square degree region in the COSMOS field, in which by now we have obtained sufficient sensitivity to extract statistically relevant galaxy number counts, and by using auxiliary data, redshift distributions. We will present first results that complement those obtained in the deeper GDF.

  19. Large-Scale Transportation Network Congestion Evolution Prediction Using Deep Learning Theory

    PubMed Central

    Ma, Xiaolei; Yu, Haiyang; Wang, Yunpeng; Wang, Yinhai

    2015-01-01

    Understanding how congestion at one location can cause ripples throughout large-scale transportation network is vital for transportation researchers and practitioners to pinpoint traffic bottlenecks for congestion mitigation. Traditional studies rely on either mathematical equations or simulation techniques to model traffic congestion dynamics. However, most of the approaches have limitations, largely due to unrealistic assumptions and cumbersome parameter calibration process. With the development of Intelligent Transportation Systems (ITS) and Internet of Things (IoT), transportation data become more and more ubiquitous. This triggers a series of data-driven research to investigate transportation phenomena. Among them, deep learning theory is considered one of the most promising techniques to tackle tremendous high-dimensional data. This study attempts to extend deep learning theory into large-scale transportation network analysis. A deep Restricted Boltzmann Machine and Recurrent Neural Network architecture is utilized to model and predict traffic congestion evolution based on Global Positioning System (GPS) data from taxi. A numerical study in Ningbo, China is conducted to validate the effectiveness and efficiency of the proposed method. Results show that the prediction accuracy can achieve as high as 88% within less than 6 minutes when the model is implemented in a Graphic Processing Unit (GPU)-based parallel computing environment. The predicted congestion evolution patterns can be visualized temporally and spatially through a map-based platform to identify the vulnerable links for proactive congestion mitigation. PMID:25780910

  20. Large-scale transportation network congestion evolution prediction using deep learning theory.

    PubMed

    Ma, Xiaolei; Yu, Haiyang; Wang, Yunpeng; Wang, Yinhai

    2015-01-01

    Understanding how congestion at one location can cause ripples throughout large-scale transportation network is vital for transportation researchers and practitioners to pinpoint traffic bottlenecks for congestion mitigation. Traditional studies rely on either mathematical equations or simulation techniques to model traffic congestion dynamics. However, most of the approaches have limitations, largely due to unrealistic assumptions and cumbersome parameter calibration process. With the development of Intelligent Transportation Systems (ITS) and Internet of Things (IoT), transportation data become more and more ubiquitous. This triggers a series of data-driven research to investigate transportation phenomena. Among them, deep learning theory is considered one of the most promising techniques to tackle tremendous high-dimensional data. This study attempts to extend deep learning theory into large-scale transportation network analysis. A deep Restricted Boltzmann Machine and Recurrent Neural Network architecture is utilized to model and predict traffic congestion evolution based on Global Positioning System (GPS) data from taxi. A numerical study in Ningbo, China is conducted to validate the effectiveness and efficiency of the proposed method. Results show that the prediction accuracy can achieve as high as 88% within less than 6 minutes when the model is implemented in a Graphic Processing Unit (GPU)-based parallel computing environment. The predicted congestion evolution patterns can be visualized temporally and spatially through a map-based platform to identify the vulnerable links for proactive congestion mitigation. PMID:25780910

  1. CP survey of deep water structures and subsea installations using an ROV

    SciTech Connect

    Leask, L.J. )

    1989-01-01

    The successful and efficient CP survey of a deep water structure using a remotely operated vehicle (ROV) has remained an enigma to many corrosion engineers in oil companies. The location of the corrosion group within the company structure often plays a major role in the success of the project. Operators locate their corrosion departments in different groups, some in the offshore/onshore operations and others in the design group. This location often has a bearing on the financial and operational approach to the project. This paper discusses how a successful CP survey is both an achievable and exciting project with experienced pre- planning and selection of the correct equipment.

  2. Cathodic protection survey of deep-water structures and subsea installations

    SciTech Connect

    Leask, L.J. )

    1989-11-01

    The successful and efficient cathodic protection (CP) survey of a deep water structure using a remotely operated vehicle (ROV) has remained an enigma to many corrosion engineers in oil companies. The location of the corrosion group within the company structure often plays a major role in the success of the project. Operators locate their corrosion departments in different groups, some in the offshore/onshore operations and others in the design group. This location often has a bearing on the financial and operational approach to the project. The author discusses how a successful CP survey is both an achievable and exciting project with experienced preplanning and selection of the correct equipment.

  3. Did shifting seawater sulfate concentrations drive the evolution of deep-sea methane-seep ecosystems?

    PubMed

    Kiel, Steffen

    2015-04-01

    The origin and evolution of the faunas inhabiting deep-sea hydrothermal vents and methane seeps have been debated for decades. These faunas rely on a local source of sulfide and other reduced chemicals for nutrition, which spawned the hypothesis that their evolutionary history is independent from that of photosynthesis-based food chains and instead driven by extinction events caused by deep-sea anoxia. Here I use the fossil record of seep molluscs to show that trends in body size, relative abundance and epifaunal/infaunal ratios track current estimates of seawater sulfate concentrations through the last 150 Myr. Furthermore, the two main faunal turnovers during this time interval coincide with major changes in seawater sulfate concentrations. Because sulfide at seeps originates mostly from seawater sulfate, variations in sulfate concentrations should directly affect the base of the food chain of this ecosystem and are thus the likely driver of the observed macroecologic and evolutionary patterns. The results imply that the methane-seep fauna evolved largely independently from developments and mass extinctions affecting the photosynthesis-based biosphere and add to the growing body of evidence that the chemical evolution of the oceans had a major impact on the evolution of marine life. PMID:25716797

  4. Did shifting seawater sulfate concentrations drive the evolution of deep-sea methane-seep ecosystems?

    PubMed Central

    Kiel, Steffen

    2015-01-01

    The origin and evolution of the faunas inhabiting deep-sea hydrothermal vents and methane seeps have been debated for decades. These faunas rely on a local source of sulfide and other reduced chemicals for nutrition, which spawned the hypothesis that their evolutionary history is independent from that of photosynthesis-based food chains and instead driven by extinction events caused by deep-sea anoxia. Here I use the fossil record of seep molluscs to show that trends in body size, relative abundance and epifaunal/infaunal ratios track current estimates of seawater sulfate concentrations through the last 150 Myr. Furthermore, the two main faunal turnovers during this time interval coincide with major changes in seawater sulfate concentrations. Because sulfide at seeps originates mostly from seawater sulfate, variations in sulfate concentrations should directly affect the base of the food chain of this ecosystem and are thus the likely driver of the observed macroecologic and evolutionary patterns. The results imply that the methane-seep fauna evolved largely independently from developments and mass extinctions affecting the photosynthesis-based biosphere and add to the growing body of evidence that the chemical evolution of the oceans had a major impact on the evolution of marine life. PMID:25716797

  5. The most distant galaxy clusters in the SPT Spitzer Deep Field Survey

    NASA Astrophysics Data System (ADS)

    Rettura, Alessandro; Stanford, S. A.; Stern, D.; Mei, S.; Brodwin, M.; Gonzalez, A. H.; Gettings, D.; Ashby, M.; Bartlett, J.; Rosati, P.

    2014-01-01

    We present a sample of more than 300 galaxy cluster candidates at z>1.3 selected within 94 deg2 from the Spitzer SPT Deep Field (SSDF) survey. To discover distant clusters at z>1.3, we have used a three-filter algorithm based upon Spitzer/IRAC color ([3.6]-[4.5]>-0.1,AB) combined with a non-detection in shallow optical data. Our sample is selected to be a complete stellar mass-limited sample at z>1.3 and therefore has a well defined survey volume. The uniqueness of SSDF resides not just in its area, one of the very largest with Spitzer, but also in its coverage by deep observations for the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope (SPT). Deeper observations are also planned with the new SPT camera, SPTpol, that will reach, for the first time, SZ clusters up to 2 (George et al., 2012). This field also has deep X-ray observations from the XMM XXL Survey (Pierre et al., 2012). Thanks to this rich data set, we will be able to determine accurate cluster masses for the vast majority of our SSDF clusters at 1.3

  6. CSTACK: A Web-Based Stacking Analysis Tool for Deep/Wide Chandra Surveys

    NASA Astrophysics Data System (ADS)

    Miyaji, Takamitsu; Griffiths, R. E.; C-COSMOS Team

    2008-03-01

    Stacking analysis is a strong tool to probe the average X-ray properties of X-ray faint objects as a class, each of which are fainter than the detection limit as an individual source. This is especially the case for deep/wide surveys with Chandra, with its superb spatial resolution and the existence of survey data on the fields with extensive multiwavelength coverages. We present an easy-to use web-based tool (http://saturn.phys.cmu.edu/cstack), which enables users to perform a stacking analysis on a number of Chandra survey fields.Currently supported are C-COSMOS, Extended Chandra Deep Field South (proprietary access, password protected), Chandra Deep Fields South, and North (Guest access user=password=guest). For an input list of positions (e.g. galaxies selected from an optical catalog), the WWW tool returns stacked Chandra images in soft and hard bands and statistical analysis results including bootstrap histograms. We present running examples on the C-COSMOS data. The next version will also include the use of off-axis dependent aperture size, automatic exclusions of resolved sources, and histograms of stacks on random positions.

  7. CANDELS MULTIWAVELENGTH CATALOGS: SOURCE IDENTIFICATION AND PHOTOMETRY IN THE CANDELS UKIDSS ULTRA-DEEP SURVEY FIELD

    SciTech Connect

    Galametz, Audrey; Grazian, Andrea; Fontana, Adriano; Castellano, Marco; Ferguson, Henry C.; Dahlen, Tomas; Grogin, Norman; Huang, Kuang-Han; Koekemoer, Anton M.; Ashby, M. L. N.; Willner, S. P.; Barro, Guillermo; Faber, Sandy M.; Guo, Yicheng; Kocevski, Dale D.; Lee, Kyoung-Soo; McGrath, Elizabeth J.; Peth, Michael; Almaini, Omar; Collaboration: CANDELS team; and others

    2013-06-01

    We present the multiwavelength-ultraviolet to mid-infrared-catalog of the UKIRT Infrared Deep Sky Survey (UKIDSS) Ultra-Deep Survey field observed as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). Based on publicly available data, the catalog includes the CANDELS data from the Hubble Space Telescope (near-infrared WFC3 F125W and F160W data and visible ACS F606W and F814W data); u-band data from CFHT/Megacam; B, V, R{sub c} , i', and z' band data from Subaru/Suprime-Cam; Y and K{sub s} band data from VLT/HAWK-I; J, H, and K band data from UKIDSS (Data Release 8); and Spitzer/IRAC data (3.6, 4.5 {mu}m from SEDS; 5.8 and 8.0 {mu}m from SpUDS). The present catalog is F160W-selected and contains 35, 932 sources over an area of 201.7 arcmin{sup 2} and includes radio- and X-ray-detected sources and spectroscopic redshifts available for 210 sources.

  8. Large-scale fluctuations in the number density of galaxies in independent surveys of deep fields

    NASA Astrophysics Data System (ADS)

    Shirokov, S. I.; Lovyagin, N. Yu.; Baryshev, Yu. V.; Gorokhov, V. L.

    2016-06-01

    New arguments supporting the reality of large-scale fluctuations in the density of the visible matter in deep galaxy surveys are presented. A statistical analysis of the radial distributions of galaxies in the COSMOS and HDF-N deep fields is presented. Independent spectral and photometric surveys exist for each field, carried out in different wavelength ranges and using different observing methods. Catalogs of photometric redshifts in the optical (COSMOS-Zphot) and infrared (UltraVISTA) were used for the COSMOS field in the redshift interval 0.1 < z < 3.5, as well as the zCOSMOS (10kZ) spectroscopic survey and the XMM-COSMOS and ALHAMBRA-F4 photometric redshift surveys. The HDFN-Zphot and ALHAMBRA-F5 catalogs of photometric redshifts were used for the HDF-N field. The Pearson correlation coefficient for the fluctuations in the numbers of galaxies obtained for independent surveys of the same deep field reaches R = 0.70 ± 0.16. The presence of this positive correlation supports the reality of fluctuations in the density of visible matter with sizes of up to 1000 Mpc and amplitudes of up to 20% at redshifts z ~ 2. The absence of correlations between the fluctuations in different fields (the correlation coefficient between COSMOS and HDF-N is R = -0.20 ± 0.31) testifies to the independence of structures visible in different directions on the celestial sphere. This also indicates an absence of any influence from universal systematic errors (such as "spectral voids"), which could imitate the detection of correlated structures.

  9. Pockmark formation and evolution in deep water Nigeria: Rapid hydrate growth versus slow hydrate dissolution

    NASA Astrophysics Data System (ADS)

    Sultan, N.; Bohrmann, G.; Ruffine, L.; Pape, T.; Riboulot, V.; Colliat, J.-L.; De Prunelé, A.; Dennielou, B.; Garziglia, S.; Himmler, T.; Marsset, T.; Peters, C. A.; Rabiu, A.; Wei, J.

    2014-04-01

    In previous works, it has been suggested that dissolution of gas hydrate can be responsible for pockmark formation and evolution in deep water Nigeria. It was shown that those pockmarks which are at different stages of maturation are characterized by a common internal architecture associated to gas hydrate dynamics. New results obtained by drilling into gas hydrate-bearing sediments with the MeBo seafloor drill rig in concert with geotechnical in situ measurements and pore water analyses indicate that pockmark formation and evolution in the study area are mainly controlled by rapid hydrate growth opposed to slow hydrate dissolution. On one hand, positive temperature anomalies, free gas trapped in shallow microfractures near the seafloor and coexistence of free gas and gas hydrate indicate rapid hydrate growth. On the other hand, slow hydrate dissolution is evident by low methane concentrations and almost constant sulfate values 2 m above the Gas Hydrate Occurrence Zone.

  10. The CfA Einstein Observatory extended deep X-ray survey

    NASA Technical Reports Server (NTRS)

    Primini, F. A.; Murray, S. S.; Huchra, J.; Schild, R.; Burg, R.

    1991-01-01

    All IPC exposures in the Einstein Extended Deep X-ray Survey program have been reanalyzed. The current survey covers about 2.3 sq deg with a typical limiting sensitivity of about 5 x 10 to the -14th ergs/sq cm/s in the energy range from 0.8-3.5 keV. A total of 25 IPC sources are detected above a threshold of 4.5 sigma. A total of 18 are detected independently in the HRI, leading to the identification of six with stars and 11 with extragalactic objects. The remaining sources are classified as extragalactic. The population of identified extragalactic objects is dominated by QSOs, with one or two possible clusters. The basic conclusions of the original survey remain unchanged.

  11. Deep Crustal Structure beneath Large Igneous Provinces and the Petrologic Evolution of Flood Basalts

    NASA Astrophysics Data System (ADS)

    Richards, M. A.; Ridley, V. A.

    2010-12-01

    We present a review of seismological constraints on deep crustal structures underlying large igneous provinces (LIPs), largely from wide-angle seismic refraction surveys. The main purpose of this review is to ascertain whether this seismic evidence is consistent with, or contrary to, petrological models for the genesis of flood basalt lavas. Where high-quality data are available beneath continental flood basalt (CFB) provinces (Emeishan, Columbia River, Deccan, Siberia), high-velocity structures (Vp ~6.9-7.5 km/sec) are typically found immediately overlying the Moho in layers of order ~5-15 km thick. Oceanic plateau (OP) LIPs exhibit similar layers, with a conspicuous layer of very high crustal velocity (Vp~7.7 km/sec) beneath the enormous Ontong-Java plateau. These structures are similar to inferred ultramafic underplating structures seen beneath active hotspots such as Hawaii, the Marquesas, and La Reunion. Petrogenetic models for flood basalt volcanism based on hot plume melting beneath mature lithosphere suggest that these deep seismic structures may consist in large part of cumulate bodies of olivine and clinopyroxene which result from ponding and deep-crustal fractionation of ultramafic primary melts. Such fractionation is necessary to produce basalts with typical MgO contents of ~6-8%, as observed for the vast bulk of observed flood basalts, from primary melts with MgO contents of order ~15-18% (or greater) such as result from hot, deep melting beneath the lithosphere. The volumes of cumulate bodies and ultramafic intrusions in the lowermost crust, often described in the literature as “underplating,” are comparable to those of the overlying basaltic formations, also consistent with petrological models. Further definition of the deep seismic structure beneath such prominent LIPs as the Ontong-Java Plateau could place better constraints on flood basalt petrogenesis by determining the relative volumes of ultramafic bodies and basaltic lavas, thereby better

  12. Deep Crustal Structure beneath Large Igneous Provinces and the Petrologic Evolution of Flood Basalts

    NASA Astrophysics Data System (ADS)

    Richards, Mark; Ridley, Victoria

    2010-05-01

    We present a review of seismological constraints on deep crustal structures underlying large igneous provinces (LIPs), largely from wide-angle seismic refraction surveys. The main purpose of this review is to ascertain whether this seismic evidence is consistent with, or contrary to, petrological models for the genesis of flood basalt lavas. Where high-quality data are available beneath continental flood basalt (CFB) provinces (Emeishan, Columbia River, Deccan, Siberia), high-velocity structures (Vp ~6.9-7.5 km/sec) are typically found immediately overlying the Moho in layers of order ~5-15 km thick. Oceanic plateau (OP) LIPs exhibit similar layers, with a conspicuous layer of very high crustal velocity (Vp~7.7 km/sec) beneath the enormous Ontong-Java plateau. These structures are similar to inferred ultramafic underplating structures seen beneath active hotspots such as Hawaii, the Marqueses, and La Reunion. Petrogenetic models for flood basalt volcanism based on hot plume melting beneath mature lithosphere suggest that these deep seismic structures may consist in large part of cumulate bodies of olivine and clinopyroxene which result from ponding and deep-crustal fractionation of ultramafic primary melts. Such fractionation is necessary to produce basalts with typical MgO contents of ~6-8%, as observed for the vast bulk of observed flood basalts, from primary melts with MgO contents of order ~15-18% (or greater) such as result from hot, deep melting beneath the lithosphere. The volumes of cumulate bodies and ultramafic intrusions in the lowermost crust, often described in the literature as "underplating," are comparable to those of the overlying basaltic formations, also consistent with petrological models. Further definition of the deep seismic structure beneath such prominent LIPs as the Ontong-Java Plateau could place better constraints on flood basalt petrogenesis by determining the relative volumes of ultramafic bodies and basaltic lavas, thereby better

  13. Deep crustal structure beneath large igneous provinces and the petrologic evolution of flood basalts

    NASA Astrophysics Data System (ADS)

    Ridley, Victoria A.; Richards, Mark A.

    2010-09-01

    We present a review of seismological constraints on deep crustal structures underlying large igneous provinces (LIPs), largely from wide-angle seismic refraction surveys. The main purpose of this review is to ascertain whether this seismic evidence is consistent with, or contrary to, petrological models for the genesis of flood basalt lavas. Where high-quality data are available beneath continental flood basalt (CFB) provinces (Emeishan, Columbia River, Deccan, Siberia), high-velocity structures (Vp ˜ 6.9-7.5 km/sec) are typically found immediately overlying the Moho in layers of order ˜5-15 km thick. Oceanic plateau (OP) LIPs exhibit similar layers, with a conspicuous layer of very high crustal velocity (Vp ˜ 7.7 km/sec) beneath the enormous Ontong-Java plateau. These structures are similar to inferred ultramafic underplating structures seen beneath active hot spots such as Hawaii, the Marquesas, and La Reunion. Petrogenetic models for flood basalt volcanism based on hot plume melting beneath mature lithosphere suggest that these deep seismic structures may consist in large part of cumulate bodies of olivine and clinopyroxene which result from ponding and deep-crustal fractionation of ultramafic primary melts. Such fractionation is necessary to produce basalts with typical MgO contents of ˜6-8%, as observed for the vast bulk of observed flood basalts, from primary melts with MgO contents of order ˜15-18% (or greater) such as result from hot, deep melting beneath the lithosphere. The volumes of cumulate bodies and ultramafic intrusions in the lowermost crust, often described in the literature as "underplating," are comparable to those of the overlying basaltic formations, also consistent with petrological models. Further definition of the deep seismic structure beneath such prominent LIPs as the Ontong-Java Plateau could place better constraints on flood basalt petrogenesis by determining the relative volumes of ultramafic bodies and basaltic lavas, thereby

  14. Convective scale interaction: Arc cloud lines and the development and evolution of deep convection

    NASA Technical Reports Server (NTRS)

    Purdom, James Francis Whitehurst

    1986-01-01

    Information is used from satellite data and research aircraft data to provide new insights concerning the mesoscale development and evolution of deep convection in an atmosphere typified by weak synoptic-scale forcing. The importance of convective scale interaction in the development and evolution of deep convection is examined. This interaction is shown to manifest itself as the merger and intersection of thunderstorm outflow boundaries (arc cloud lines) with other convective lines, areas or boundaries. Using geostationary satellite visible and infrared data convective scale interaction is shown to be responsible for over 85 percent of the intense convection over the southeast U.S. by late afternoon, and a majority of that area's afternoon rainfall. The aircraft observations provided valuable information concerning critically important regions of the arc cloud line: (1) the cool outflow region, (2) the density surge line interface region; and (3) the sub-cloud region above the surge line. The observations when analyzed with rapid scan satellite data, helped in defining the arc cloud line's life cycle as 3 evolving stages.

  15. Pressure tomography for exploring CO2 plume evolution in a deep saline homogeneous aquifer

    NASA Astrophysics Data System (ADS)

    Hu, Linwei; Bayer, Peter; Alt-Epping, Peter; Tatomir, Alexandru; Sauter, Martin; Brauchler, Ralf

    2015-04-01

    Deep saline aquifers serve as the potential CO2 storage formations due to their often large storage capacity. For characterizing and monitoring CO2 migration in deep saline aquifers, cost-efficient and expressive field methods are required to provide direct insight into the prevailing physical conditions of the subsurface. In our study, we propose an innovative pressure tomography approach to characterize the initial flow properties of the aquifer and the development of CO2 plume based on a virtual homogeneous saline aquifer. Deep CO2 injection has an impact on the flow properties of the CO2 and brine mixture depending on the saturation. Variations of the flow properties, such as hydraulic diffusivity, are considered as indicators for tracking the plume, which can roughly be approximated by a single-phase model. Comparable to seismic tomography experiments, pressure tomography generates streamline patterns by either injecting brine at variable depths (sources) prior to full-scale CO2 injection, or by injecting small amounts of CO2 into the CO2-brine system during later stages of storage. The streamlines are derived by recording the introduced pressure responses at given observation locations (receivers). An eikonal-based pressure tomographical framework allows the quantification of the apparent single-phase or mixed-phase diffusivity of the formation. By applying the inversion at different times and by comparison of the inverted diffusivity tomograms, the evolution of the CO2 plume shape can be monitored temporally in a time-lapse strategy.

  16. The Hawk-I UDS and GOODS Survey (HUGS): Survey design and deep K-band number counts

    NASA Astrophysics Data System (ADS)

    Fontana, A.; Dunlop, J. S.; Paris, D.; Targett, T. A.; Boutsia, K.; Castellano, M.; Galametz, A.; Grazian, A.; McLure, R.; Merlin, E.; Pentericci, L.; Wuyts, S.; Almaini, O.; Caputi, K.; Chary, R.-R.; Cirasuolo, M.; Conselice, C. J.; Cooray, A.; Daddi, E.; Dickinson, M.; Faber, S. M.; Fazio, G.; Ferguson, H. C.; Giallongo, E.; Giavalisco, M.; Grogin, N. A.; Hathi, N.; Koekemoer, A. M.; Koo, D. C.; Lucas, R. A.; Nonino, M.; Rix, H. W.; Renzini, A.; Rosario, D.; Santini, P.; Scarlata, C.; Sommariva, V.; Stark, D. P.; van der Wel, A.; Vanzella, E.; Wild, V.; Yan, H.; Zibetti, S.

    2014-10-01

    We present the results of a new, ultra-deep, near-infrared imaging survey executed with the Hawk-I imager at the ESO VLT, of which we make all the data (images and catalog) public. This survey, named HUGS (Hawk-I UDS and GOODS Survey), provides deep, high-quality imaging in the K and Y bands over the portions of the UKIDSS UDS and GOODS-South fields covered by the CANDELS HST WFC3/IR survey. In this paper we describe the survey strategy, the observational campaign, the data reduction process, and the data quality. We show that, thanks to exquisite image quality and extremely long exposure times, HUGS delivers the deepest K-band images ever collected over areas of cosmological interest, and in general ideally complements the CANDELS data set in terms of image quality and depth. In the GOODS-S field, the K-band observations cover the whole CANDELS area with a complex geometry made of 6 different, partly overlapping pointings, in order to best match the deep and wide areas of CANDELS imaging. In the deepest region (which includes most of the Hubble Ultra Deep Field) exposure times exceed 80 hours of integration, yielding a 1 - σ magnitude limit per square arcsec of ≃28.0 AB mag. The seeing is exceptional and homogeneous across the various pointings, confined to the range 0.38-0.43 arcsec. In the UDS field the survey is about one magnitude shallower (to match the correspondingly shallower depth of the CANDELS images) but includes also Y-band band imaging (which, in the UDS, was not provided by the CANDELS WFC3/IR imaging). In the K-band, with an average exposure time of 13 hours, and seeing in the range 0.37-0.43 arcsec, the 1 - σ limit per square arcsec in the UDS imaging is ≃27.3 AB mag. In the Y-band, with an average exposure time ≃8 h, and seeing in the range 0.45-0.5 arcsec, the imaging yields a 1 - σ limit per square arcsec of ≃28.3 AB mag. We show that the HUGS observations are well matched to the depth of the CANDELS WFC3/IR data, since the majority

  17. Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey -- GOODS-South Field, Non-SNe-Searched Visits

    NASA Astrophysics Data System (ADS)

    Faber, Sandra

    2011-10-01

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey {CANDELS}is designed to document the ?rst third of galactic evolution from z =8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IRand ACS. It will also find the first Type Ia SNe beyond z > 1.5 andestablish their accuracy as standard candles for cosmology. Fivepremier multi-wavelength sky regions selected from the SpitzerExtragalactic Deep Survey {SEDS} provide complementary IRAC imagingdata down to 26.5 AB mag, a unique resource for stellar masses at allredshifts. The use of ?ve widely separated ?elds mitigates cosmicvariance and yields statistically robust and complete samples ofgalaxies down to 10^9 solar masses out to z 8.The program merges two originally separate MCT proposals. The Faberprogram incorporates a ?Wide? imaging survey in three separate fieldsto 2 orbit depth over 0.2 sq. degrees, plus a ?Deep? imaging surveyto 12 orbit depth in the two GOODS regions over 0.04 sq. degrees.When combined with ultra-deep imaging from the Hubble Ultradeep Fieldprogram {GO 11563}, the result is a three-tiered strategy that ef?cientlysamples both bright/rare and faint/common extragalactic objects. TheFerguson program adds an extensive high-redshift Type Ia SNe search,plus ultraviolet "daytime" UVIS exposures in GOODS-N to exploit theCVZ opportunity in that field.This program, GO 12064, is part of the Wide mosaic survey, which has thefollowing field centers and sizes: Field ID RA{2000} Dec{2000} WFC3 Dim. PA on sky UDS 02 17 38 -05 12 02 4x11 270 COSMOS 10 00 31 +02 24 00 4x11 180 EGS 14 19 31 +52 54 10 3x15 41 Science highlights from the Wide program: * Underlying structural properties of galaxies as revealed by WFC3-IR images sensitive to older stars {beyond the 4000-A break} and less affected by dust than ACS. A key redshift is z 2, where star-formation peaks, QSOs are most abundant, and where restframe B-band is still accessible to WFC3. Sample questions include: - Structure in young vs. old

  18. THE DEEP2 GALAXY REDSHIFT SURVEY: THE VORONOI-DELAUNAY METHOD CATALOG OF GALAXY GROUPS

    SciTech Connect

    Gerke, Brian F.; Newman, Jeffrey A.; Davis, Marc; Coil, Alison L.; Cooper, Michael C.; Dutton, Aaron A.; Faber, S. M.; Guhathakurta, Puragra; Koo, David C.; Phillips, Andrew C.; Noeske, Kai; Rosario, David J.; Weiner, Benjamin J.; Willmer, Christopher N. A.; Yan, Renbin

    2012-05-20

    We present a public catalog of galaxy groups constructed from the spectroscopic sample of galaxies in the fourth data release from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Galaxy Redshift Survey, including the Extended Groth Strip (EGS). The catalog contains 1165 groups with two or more members in the EGS over the redshift range 0 < z < 1.5 and 1295 groups at z > 0.6 in the rest of DEEP2. Twenty-five percent of EGS galaxies and fourteen percent of high-z DEEP2 galaxies are assigned to galaxy groups. The groups were detected using the Voronoi-Delaunay method (VDM) after it has been optimized on mock DEEP2 catalogs following similar methods to those employed in Gerke et al. In the optimization effort, we have taken particular care to ensure that the mock catalogs resemble the data as closely as possible, and we have fine-tuned our methods separately on mocks constructed for the EGS and the rest of DEEP2. We have also probed the effect of the assumed cosmology on our inferred group-finding efficiency by performing our optimization on three different mock catalogs with different background cosmologies, finding large differences in the group-finding success we can achieve for these different mocks. Using the mock catalog whose background cosmology is most consistent with current data, we estimate that the DEEP2 group catalog is 72% complete and 61% pure (74% and 67% for the EGS) and that the group finder correctly classifies 70% of galaxies that truly belong to groups, with an additional 46% of interloper galaxies contaminating the catalog (66% and 43% for the EGS). We also confirm that the VDM catalog reconstructs the abundance of galaxy groups with velocity dispersions above {approx}300 km s{sup -1} to an accuracy better than the sample variance, and this successful reconstruction is not strongly dependent on cosmology. This makes the DEEP2 group catalog a promising probe of the growth of cosmic structure that can potentially be used for cosmological tests.

  19. A WSRT 21 CM deep survey of two fields in Hercules

    NASA Astrophysics Data System (ADS)

    Oort, M. J. A.; van Langevelde, H. J.

    1987-10-01

    A deep 21 cm survey, carried out with the Westerbork Synthesis Radio Telescope (WSRT), of two fields in the constellation of Hercules is presented. These areas were observed previously at 21 cm in the Leiden-Berkeley Deep Survey (LBDS), (Windhorst et al., 1984), but with a factor of three higher noise level. A complete sample is defined, containing 116 radio sources with a peak flux above 5 sigma, within the -7dB attenuation radius (0.464 deg). This complete sample is used to determine the 1412 MHz source counts down to 0.45 mJy. The counts from the current sample show the same small scale structure at about 1 mJy, as was found in previous surveys. A direct comparison is made with the LBDS observations of the same fields. It is shown that the 5 sigma peak flux cut-off in the complete sample is not stringent enough to sufficiently avoid contamination by spurious sources, especially when strong (S of not less than 100 mJy) sources are present in the field. Finally, a search was made for the variable sources.

  20. The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method Catalog of Galaxy Groups

    SciTech Connect

    Gerke, Brian F.; Newman, Jeffrey A.; Davis, Marc; Marinoni, Christian; Yan, Renbin; Coil, Alison L.; Conroy, Charlie; Cooper, Michael C.; Faber, S.M.; Finkbeiner, Douglas P.; Guhathakurta, Puragra; Kaiser, Nick; Koo, David C.; Phillips, Andrew C.; Weiner, Benjamin J.; /Maryland U.

    2012-02-14

    We use the first 25% of the DEEP2 Galaxy Redshift Survey spectroscopic data to identify groups and clusters of galaxies in redshift space. The data set contains 8370 galaxies with confirmed redshifts in the range 0.7 {<=} z {<=} 1.4, over one square degree on the sky. Groups are identified using an algorithm (the Voronoi-Delaunay Method) that has been shown to accurately reproduce the statistics of groups in simulated DEEP2-like samples. We optimize this algorithm for the DEEP2 survey by applying it to realistic mock galaxy catalogs and assessing the results using a stringent set of criteria for measuring group-finding success, which we develop and describe in detail here. We find in particular that the group-finder can successfully identify {approx}78% of real groups and that {approx}79% of the galaxies that are true members of groups can be identified as such. Conversely, we estimate that {approx}55% of the groups we find can be definitively identified with real groups and that {approx}46% of the galaxies we place into groups are interloper field galaxies. Most importantly, we find that it is possible to measure the distribution of groups in redshift and velocity dispersion, n({sigma}, z), to an accuracy limited by cosmic variance, for dispersions greater than 350 km s{sup -1}. We anticipate that such measurements will allow strong constraints to be placed on the equation of state of the dark energy in the future. Finally, we present the first DEEP2 group catalog, which assigns 32% of the galaxies to 899 distinct groups with two or more members, 153 of which have velocity dispersions above 350 km s{sup -1}. We provide locations, redshifts and properties for this high-dispersion subsample. This catalog represents the largest sample to date of spectroscopically detected groups at z {approx} 1.

  1. Experimental palaeobiomechanics: What can engineering tell us about evolution in deep time?

    NASA Astrophysics Data System (ADS)

    Anderson, Philip

    2016-04-01

    What did Tyrannosaurus rex eat? This is the sort of question that immediately bombards any palaeontologist when interacting with the general public. Even among scientists, how extinct animals moved or fed is a major objective of the palaeobiological research agenda. The last decade has seen a sharp increase in the technology and experimental methods available for collecting biomechanical data, which has greatly improved out ability to examine the function of both live and extinct animals. With new technologies and methods come new pitfalls and opportunities. In this review, I address three aspects of experimental biomechanics that exemplify the challenges and opportunities it provides for addressing deep-time problems in palaeontology. 1) Interpretation: It has never been easier to acquire large amounts of high-quality biomechanical data on extinct animals. However, the lack of behavioural information means that interpreting this data can be problematic. We will never know precisely what a dinosaur ate, but we can explore what constraints there might have been on the mechanical function of its jaws. Palaeobiomechanics defines potential function and becomes especially effective when dealing with multiple examples. 2) Comparison: Understanding the potential function of one extinct animal is interesting; however, examining mechanical features across multiple taxa allows for a greater understanding of biomechanical variation. Comparative studies help identify common trends and underlying mechanical principles which can have long reaching influences on morphological evolution. 3) Evolution: The physical principles established through comparative biomechanical studies can be utilized in phylogenetic comparative methods in order to explore evolutionary morphology across clades. Comparative evolutionary biomechanics offers potential for exploring the evolution of functional systems in deep time utilizing experimental biomechanical data.

  2. OT2_sserje01_2: THE HERSCHEL-AKARI NEP DEEP SURVEY: the cosmological history of stellar mass assembly and black hole accretion

    NASA Astrophysics Data System (ADS)

    Serjeant, S.

    2011-09-01

    We propose a far-IR and submm mapping survey of the premier AKARI deep field in the North Ecliptic Pole, in PACS/SPIRE parallel mode. This is the only major deep infrared field not yet covered by Herschel guaranteed or open time key projects. The outstanding and unparalleled continuous mid-IR photometric coverage from AKARI, far better than equivalent Spitzer surveys, enables a wide range of galaxy evolution diagnostics unachievable in any other survey field (including Herschel HerMES/PEP fields), by spanning the wavelengths of redshifted PAH and silicate features and the peak energy output of AGN dust tori. The investment by AKARI in the NEP represents ~10 percent of the entire pointed observations available throughout the lifetime of AKARI. Our proposal remedies the remarkable omission from Herschel's legacy surveys of the premier extragalactic deep field from another IR space telescope. We will simultaneously identify and find photometric redshifts for the Herschel point source population, make stacking analysis detections of the galaxies which dominate the submm extragalactic background light as a function of redshift, determine the bolometric power outputs of the galaxies that dominate the submm background, compare the UV/optical/mid-IR continuum/PAH/far-IR/submm/radio star formation rate estimator in the most comprehensive IR survey data set to date, and track the coupled stellar mass assembly and black hole accretion throughout most of the history of the Universe. In OT1 the HOTAC concluded "The science output from the proposed survey will be outstanding [...] The panel was convinced that these observations should be done" but it since became clear that priority 2 time is very unlikely to be executed, so we request reclassification to priority 1.

  3. Mass and Light Correlated with Galaxies on Local and Cosmic Scales: Weak Gravitational Lensing in the Deep Lens Survey

    NASA Astrophysics Data System (ADS)

    Choi, Ami

    In this dissertation, we describe the results of applying weak gravitational lensing techniques to probe the connection between luminous galaxies and the dark matter halos in which they live. Specifically, we study galaxy-shear correlations in the Deep Lens Survey, and we investigate how this function changes with observable galaxy properties such as stellar mass, luminosity, color, and redshift. In Chapter 3, we examine the galaxy-shear correlation function on a large range of scales from small radii where the dominant contribution is from halos associated with individual galaxies to large radii where the dominant contribution is from neighboring galaxies and large-scale structure. We study the lensing signal for galaxies binned by luminosity and find that more luminous galaxies are more massive. More interestingly, the galaxy-shear correlation function shows features consistent with satellite and 2-halo terms from the halo model and cannot be fit with a single power law out to 15 Mpc. We also find more correlated large scale structure mass at lower redshift, consistent with the paradigm of bottom-up hierarchical structure formation. In Chapter 4, we focus on a subset of the survey with ancillary infrared data that allow estimates of stellar mass. We study the lensing signal for galaxies binned by stellar mass and infer the nature and evolution of the relationship between virial mass and stellar mass. We show that stellar mass and virial mass scale such that galaxies with smaller stellar masses also have smaller virial masses. This work has implications for the idea of downsizing, but does not yet have the S/N to provide competitive constraints. In the process of making lensing measurements on the Deep Lens Survey, we have also investigated errors related to the two most important variables: shapes and photometric redshifts. we discuss our findings in the context of the survey characteristics in Chapter 2 and in the simulations section of Chapter 3. While neither

  4. The Spitzer South Pole Telescope Deep Field: Survey Design and Infrared Array Camera Catalogs

    NASA Astrophysics Data System (ADS)

    Ashby, M. L. N.; Stanford, S. A.; Brodwin, M.; Gonzalez, A. H.; Martinez-Manso, J.; Bartlett, J. G.; Benson, B. A.; Bleem, L. E.; Crawford, T. M.; Dey, A.; Dressler, A.; Eisenhardt, P. R. M.; Galametz, A.; Jannuzi, B. T.; Marrone, D. P.; Mei, S.; Muzzin, A.; Pacaud, F.; Pierre, M.; Stern, D.; Vieira, J. D.

    2013-12-01

    The Spitzer South Pole Telescope Deep Field (SSDF) is a wide-area survey using Spitzer's Infrared Array Camera (IRAC) to cover 94 deg2 of extragalactic sky, making it the largest IRAC survey completed to date outside the Milky Way midplane. The SSDF is centered at (α, δ) = (23:30, -55:00), in a region that combines observations spanning a broad wavelength range from numerous facilities. These include millimeter imaging from the South Pole Telescope, far-infrared observations from Herschel/SPIRE, X-ray observations from the XMM XXL survey, near-infrared observations from the VISTA Hemisphere Survey, and radio-wavelength imaging from the Australia Telescope Compact Array, in a panchromatic project designed to address major outstanding questions surrounding galaxy clusters and the baryon budget. Here we describe the Spitzer/IRAC observations of the SSDF, including the survey design, observations, processing, source extraction, and publicly available data products. In particular, we present two band-merged catalogs, one for each of the two warm IRAC selection bands. They contain roughly 5.5 and 3.7 million distinct sources, the vast majority of which are galaxies, down to the SSDF 5σ sensitivity limits of 19.0 and 18.2 Vega mag (7.0 and 9.4 μJy) at 3.6 and 4.5 μm, respectively.

  5. Evidence for isolated evolution of deep-sea ciliate communities through geological separation and environmental selection

    PubMed Central

    2013-01-01

    Background Deep hypersaline anoxic basins (DHABs) are isolated habitats at the bottom of the eastern Mediterranean Sea, which originate from the ancient dissolution of Messinian evaporites. The different basins have recruited their original biota from the same source, but their geological evolution eventually constituted sharp environmental barriers, restricting genetic exchange between the individual basins. Therefore, DHABs are unique model systems to assess the effect of geological events and environmental conditions on the evolution and diversification of protistan plankton. Here, we examine evidence for isolated evolution of unicellular eukaryote protistan plankton communities driven by geological separation and environmental selection. We specifically focused on ciliated protists as a major component of protistan DHAB plankton by pyrosequencing the hypervariable V4 fragment of the small subunit ribosomal RNA. Geospatial distributions and responses of marine ciliates to differential hydrochemistries suggest strong physical and chemical barriers to dispersal that influence the evolution of this plankton group. Results Ciliate communities in the brines of four investigated DHABs are distinctively different from ciliate communities in the interfaces (haloclines) immediately above the brines. While the interface ciliate communities from different sites are relatively similar to each other, the brine ciliate communities are significantly different between sites. We found no distance-decay relationship, and canonical correspondence analyses identified oxygen and sodium as most important hydrochemical parameters explaining the partitioning of diversity between interface and brine ciliate communities. However, none of the analyzed hydrochemical parameters explained the significant differences between brine ciliate communities in different basins. Conclusions Our data indicate a frequent genetic exchange in the deep-sea water above the brines. The “isolated island

  6. The cosmological significance of low surface brightness galaxies found in a deep blind neutral hydrogen survey

    NASA Astrophysics Data System (ADS)

    Minchin, R. F.; Disney, M. J.; Parker, Q. A.; Boyce, P. J.; de Blok, W. J. G.; Banks, G. D.; Ekers, R. D.; Freeman, K. C.; Garcia, D. A.; Gibson, B. K.; Grossi, M.; Haynes, R. F.; Knezek, P. M.; Lang, R. H.; Malin, D. F.; Price, R. M.; Putman, M.; Stewart, I. M.; Wright, A. E.

    2004-12-01

    Minchin et al. have recently placed limits on the cosmological significance of gas-rich low surface brightness (LSB) galaxies as a proportion of the total population of gas-rich galaxies by carrying out a very deep survey (HIDEEP) for neutral hydrogen (HI) with the Parkes multibeam system. Such a survey avoids the surface brightness selection effects that limit the usefulness of optical surveys for finding LSB galaxies. To complement the HIDEEP survey, we have digitally stacked eight 1-h R-band Tech Pan films from the UK Schmidt Telescope covering 36 deg2 of the survey area to reach a very deep isophotal limit of 26.5 Rmag arcsec-2. At this level, we find that all of the 129 HI sources within this area have optical counterparts and that 107 of them can be identified with individual galaxies. We have used the properties of the galaxies identified as the optical counterparts of the HI sources to estimate the significance of LSB galaxies (defined to be those at least 1.5 mag dimmer in effective surface brightness than the peak in the observed distribution seen in optical surveys). Two different methods of correcting for ease of detection do not yield significantly different results: LSB galaxies make up 62 +/- 37 per cent of gas-rich galaxies by number according to our first method (weighting by HI mass function), which includes a correction for large-scale structure, or 51 +/- 20 per cent when calculated by our second method (1/Vmax correction). We also find that LSB galaxies provide 30 +/- 10 per cent of the contribution of gas-rich galaxies to the neutral hydrogen density of the Universe, 7 +/- 3 per cent of their contribution to the luminosity density of the Universe, 9 +/- 4 of their contribution to the baryonic mass density of the Universe, 20 +/- 10 per cent of their contribution to the dynamical mass density of the Universe, and 40 +/- 20 per cent of their cross-sectional area. We do not find any `crouching giant' LSB galaxies such as Malin 1, nor do we find a

  7. Photometric identification of objects from Galaxy Evolution Explorer Survey and Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Preethi, K.; Gudennavar, S. B.; Bubbly, S. G.; Murthy, Jayant; Brosch, Noah

    Sloan Digital Sky Survey photometric observations have been cross-matched with observations from the Galaxy Evolution Explorer for high-latitude stars in the northern hemisphere (≥75°). This provides a wide range of wavelength coverage from Far Ultra-Violet through the optical spectrum and gives one unique SDSS source for every GALEX source. We discuss a sample of 84,649 point sources in the north galactic pole (NGP) from this combined database. We made use of Kinney-Calzetti spectral atlas of galaxies in combination with the Castelli & Kurucz Atlas of stellar atmosphere models, in order to create a grid of models that spans a wide range of spectral types for stars and galaxies. This grid was fit to the GALEX and SDSS data and extinctions obtained. In 54,795 (˜65%) of the total number of objects in our dataset, the fit was found to be better with the galaxy models than with the stellar models.

  8. VizieR Online Data Catalog: AKARI NEP Deep Survey revised catalog (Murata+, 2013)

    NASA Astrophysics Data System (ADS)

    Murata, K.; Matsuhara, H.; Wada, T.; Arimatsu, K.; Oi, N.; Takagi, T.; Oyabu, S.; Goto, T.; Ohyama, Y.; Malkan, M.; Pearson, C.; Malek, K.; Solarz, A.

    2013-09-01

    This is the revised catalogue of the AKARI North Ecliptic Pole Deep survey. The survey was carried out with the InfraRed Camera (IRC) onboard AKARI which has a comprehensive mid-IR wavelength coverage in nine photometric bands at 2-24 micron. For mid-IR source extraction we used a detection image while for near-IR source detection we used optical to near-IR ground-based catalogue which is based on CFHT/MegaCam z', CFHT/WIRCam Ks and Subaru/Scam z' band detection. Here we present an AKARI source with the identification from the ground-based catalogue. For objects with multiple counterparts, all of these were listed in the catalogue with an upper limit for the AKARI flux. The magnitudes are given in the AB system. (1 data file).

  9. NO EVIDENCE FOR EVOLUTION IN THE FAR-INFRARED-RADIO CORRELATION OUT TO z {approx} 2 IN THE EXTENDED CHANDRA DEEP FIELD SOUTH

    SciTech Connect

    Mao, Minnie Y.; Huynh, Minh T.; Helou, George; Norris, Ray P.; Dickinson, Mark; Frayer, Dave; Monkiewicz, Jacqueline A.

    2011-04-20

    We investigate the 70 {mu}m far-infrared-radio correlation (FRC) of star-forming galaxies in the Extended Chandra Deep Field South (ECDFS) out to z > 2. We use 70 {mu}m data from the Far-Infrared Deep Extragalactic Legacy Survey (FIDEL), which comprises the most sensitive ({approx}0.8 mJy rms) and extensive far-infrared deep field observations using MIPS on the Spitzer Space Telescope, and 1.4 GHz radio data ({approx}8 {mu}Jy beam{sup -1} rms) from the Very Large Array. In order to quantify the evolution of the FRC, we use both survival analysis and stacking techniques, which we find give similar results. We also calculate the FRC using total infrared luminosity and rest-frame radio luminosity, q{sub TIR}, and find that q{sub TIR} is constant (within 0.22) over the redshift range 0-2. We see no evidence for evolution in the FRC at 70 {mu}m, which is surprising given the many factors that are expected to change this ratio at high redshifts.

  10. Star formation and galaxy evolution since z˜2: Results from multiwavelength surveys

    NASA Astrophysics Data System (ADS)

    Brisbin, Drew

    Our recent studies in galaxy evolution have revealed a surprising new paradigm of star formation. Contrary to the notion that major mergers play an increasingly dominant role going backwards in cosmic history, we find that over the last ˜10 Gyr, much of star formation has been fueled by accreting cold gas from the cosmic web. Accretion rates were presumably larger in the past, so star forming systems may have very different properties in the early Universe and today. Large scale astronomical surveys, such as the Herschel Multi-Tiered Extragalactic Survey (HerMES), and the Sloan Digital Sky Survey (SDSS) have provided a wealth of extragalactic data covering a statistically large number of sources. Targeted, niche surveys, like our fine structure line survey of star forming galaxies in the early Universe observed with the redshift (z) Early Universe Spectrometer (ZEUS) have provided detailed observations of high interest sources. We have made use of this diverse set of data to study galaxy evolution from the epoch of peak star formation at z=1-2 up to the present. Data from HerMES is a reliable probe of infrared emission, particularly useful for characterizing the far infrared dust peak, and therefore determining star formation rates out to redshifts of a few. Deep integrations with the Herschel SPIRE photometer rapidly reach the confusion limit, tempering its utility in studying faint high redshift galaxies. With appropriate care taken to identify blended sources, however, HerMES data is useful in identifying bright, redshifted, star forming sources. We have compiled spectral energy distributions from HerMES and ancillary data and found that, even sources at high redshift are well fit by local star forming galaxy templates. In the local Universe, spectroscopic SDSS data has allowed us to estimate crucial galaxy properties on ˜105 sources, providing an opportunity to observe general statistical trends, and constrain theories of galaxy evolution. A toy model of cold

  11. Attitudes and expectations of treating deep caries: a PEARL Network survey.

    PubMed

    Oen, Kay T; Thompson, Van P; Vena, Don; Caufield, Page W; Curro, Fredrick; Dasanayake, Ananda; Ship, Jonathan A; Lindblad, Anne

    2007-01-01

    A survey was conducted within a practice-based dental research network to determine dentists' treatment methods for deep caries lesions and whether the dentists' intended treatment approaches were influenced by their expectations for pulpal exposure. The survey further examined how general dentistry practices have adopted scientific evidence of caries classification, excavation, and capping techniques. Dentists were queried regarding liner use, hypersensitivity considerations, point of endodontic therapy, and anticipated vitality outcomes from Class I resin-based composite restorations over three to five years. Of the 93 practitioner-investigators who were in the network at the time of the survey, 85 (92%) completed it. Of those who responded, 62% said that they would remove all caries when presented with a case in which one would expect pulpal exposure, while 18% would partially remove caries and 21% would initiate endodontic treatment; 17% reported that they would utilize an antimicrobial agent before a liner or bonding agent during restoration. The outcomes projected for tooth vitality over the next three to five years were equivalent regardless of the caries removal approach or the use of a liner/bonding agent. When beginning the preparation, the method of treatment did not change if a pulpal exposure was anticipated, other than a threefold increase in immediate endodontic treatment. When dentists were given a direct pulp cap scenario, the projected use of a liner/bonding agent changed little while the vitality projections decreased. Overall survey findings indicate that approximately 20% of network dentists favor partial caries removal techniques and that deep caries treatment outcome studies are warranted, given the various treatments employed. PMID:17511360

  12. The VIMOS-VLT Deep Survey. Galaxy luminosity function per morphological type up to z = 1.2

    NASA Astrophysics Data System (ADS)

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

    2006-07-01

    Aims.We have computed the evolution of the rest-frame B-band luminosity function (LF) for bulge and disk-dominated galaxies since z=1.2. Methods: .We use a sample of 605 spectroscopic redshifts with IAB≤ 24 in the Chandra Deep Field South from the VIMOS-VLT Deep Survey, 3555 galaxies with photometric redshifts from the COMBO-17 multi-color data, coupled with multi-color HST/ACS images from the Great Observatories Origin Deep Survey. We split the sample in bulge- and disk-dominated populations on the basis of asymmetry and concentration parameters measured in the rest-frame B-band. Results: .We find that at z=0.4-0.8, the LF slope is significantly steeper for the disk-dominated population (α=-1.19 ± 0.07) compared to the bulge-dominated population (α=-0.53 ± 0.13). The LF of the bulge-dominated population is composed of two distinct populations separated in rest-frame color: 68% of red (B-I)AB>0.9 and bright galaxies showing a strongly decreasing LF slope α=+0.55 ± 0.21, and 32% of blue (B-I)AB<0.9 and more compact galaxies which populate the LF faint-end. We observe that red bulge-dominated galaxies are already well in place at z≃1, but the volume density of this population is increasing by a factor 2.7 between z˜ 1 and z˜ 0.6. It may be related to the building-up of massive elliptical galaxies in the hierarchical scenario. In addition, we observe that the blue bulge-dominated population is dimming by 0.7 mag between z˜ 1 and z˜ 0.6. Galaxies in this faint and more compact population could possibly be the progenitors of the local dwarf spheroidal galaxies.

  13. The influence of deep mantle heterogeneity on the rhythms and scales of surface topography evolution

    NASA Astrophysics Data System (ADS)

    Arnould, Maëlis; Coltice, Nicolas; Flament, Nicolas

    2016-04-01

    Earth's surface, the interface between external processes and internal dynamics (lithosphere motions and mantle convection), is continuously reorganised. A large part of Earth's topography is generated by mantle motions and lithospheric stresses [1], which impacts for instance the global sea-level, the dynamics of sedimentary basins and the geoid. Studying how surface topography evolves in both space and time thus not only provides information on the rhythms and scales of evolution of those processes, but would also be a tool for the study of the mantle motions and properties from which it originates [2]. In this study, we propose to characterise the spatial and temporal scales of evolution of surface topography in 2D spherical annulus numerical models of mantle convection developing a plate-like behaviour. We use the geodynamical code StagYY [3] to first determine a mantle convection regime generating a surface topography with Earth-like amplitudes and realistic mantle dynamics at first order (e.g. high Rayleigh number, reasonable lithosphere thickness, pseudo-plastic lithosphere rheology generating plate tectonics). We then use this convection regime to investigate how the presence of stable deep-rooted thermochemical heterogeneities influence the rhythms of evolution of surface topography. We analyse our results to identify how the timescales of evolution are connected with the lengthscales of topography, in light of the tectonic histories produced by the models. References: [1] M. Gurnis, Long-term controls of eustatic and epeirogenic motions by mantle convection, GSA Today, 2(7):141-157, 1992. [2] B.H. Hager, R.W. Clayton, M.A. Richards, R.P. Comer, and A.M. Dziewonski, Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313:541-545, 1985. [3] J.W. Hernlund and P.J. Tackley, Modeling mantle convection in the spherical annulus, Phys. Earth Planet. Interiors, 171(1):48-54, 2008.

  14. SMUVS: Spitzer Matching survey of the UltraVISTA ultra-deep Stripes

    NASA Astrophysics Data System (ADS)

    Caputi, Karina; Ashby, Matthew; Fazio, Giovanni; Huang, Jiasheng; Dunlop, James; Franx, Marijn; Le Fevre, Olivier; Fynbo, Johan; McCracken, Henry; Milvang-Jensen, Bo; Muzzin, Adam; Ilbert, Olivier; Somerville, Rachel; Wechsler, Risa; Behroozi, Peter; Lu, Yu

    2014-12-01

    We request 2026.5 hours to homogenize the matching ultra-deep IRAC data of the UltraVISTA ultra-deep stripes, producing a final area of ~0.6 square degrees with the deepest near- and mid-IR coverage existing in any such large area of the sky (H, Ks, [3.6], [4.5] ~ 25.3-26.1 AB mag; 5 sigma). The UltraVISTA ultra-deep stripes are contained within the larger COSMOS field, which has a rich collection of multi-wavelength, ancillary data, making it ideal to study different aspects of galaxy evolution with high statistical significance and excellent redshift accuracy. The UltraVISTA ultra-deep stripes are the region of the COSMOS field where these studies can be pushed to the highest redshifts, but securely identifying high-z galaxies, and determining their stellar masses, will only be possible if ultra-deep mid-IR data are available. Our IRAC observations will allow us to: 1) extend the galaxy stellar mass function at redshifts z=3 to z=5 to the intermediate mass regime (M~5x10^9-10^10 Msun), which is critical to constrain galaxy formation models; 2) gain a factor of six in the area where it is possible to effectively search for z>=6 galaxies and study their properties; 3) measure, for the first time, the large-scale structure traced by an unbiased galaxy sample at z=5 to z=7, and make the link to their host dark matter haloes. This cannot be done in any other field of the sky, as the UltraVISTA ultra-deep stripes form a quasi-contiguous, regular-shape field, which has a unique combination of large area and photometric depth. 4) provide a unique resource for the selection of secure z>5 targets for JWST and ALMA follow up. Our observations will have an enormous legacy value which amply justifies this new observing-time investment in the COSMOS field. Spitzer cannot miss this unique opportunity to open up a large 0.6 square-degree window to the early Universe.

  15. The Metal Abundances across Cosmic Time (MACT) Survey. I. Optical Spectroscopy in the Subaru Deep Field

    NASA Astrophysics Data System (ADS)

    Ly, Chun; Malhotra, Sangeeta; Malkan, Matthew A.; Rigby, Jane R.; Kashikawa, Nobunari; de los Reyes, Mithi A.; Rhoads, James E.

    2016-09-01

    Deep rest-frame optical spectroscopy is critical for characterizing and understanding the physical conditions and properties of the ionized gas in galaxies. Here, we present a new spectroscopic survey called “Metal Abundances across Cosmic Time” or { M }{ A }{ C }{ T }, which will obtain rest-frame optical spectra for ∼3000 emission-line galaxies. This paper describes the optical spectroscopy that has been conducted with MMT/Hectospec and Keck/DEIMOS for ≈1900 z = 0.1–1 emission-line galaxies selected from our narrowband and intermediate-band imaging in the Subaru Deep Field. In addition, we present a sample of 164 galaxies for which we have measured the weak [O iii]λ4363 line (66 with at least 3σ detections and 98 with significant upper limits). This nebular emission line determines the gas-phase metallicity by measuring the electron temperature of the ionized gas. This paper presents the optical spectra, emission-line measurements, interstellar properties (e.g., metallicity, gas density), and stellar properties (e.g., star formation rates, stellar mass). Paper II of the { M }{ A }{ C }{ T } survey (Ly et al.) presents the first results on the stellar mass–gas metallicity relation at z ≲ 1 using the sample with [O iii]λ4363 measurements.

  16. Attitudes and behaviour regarding deep dentin caries removal: a survey among German dentists.

    PubMed

    Schwendicke, F; Meyer-Lueckel, H; Dörfer, C; Paris, S

    2013-01-01

    Incomplete removal of deep caries has been shown to reduce the risks of pulp exposure and postoperative pulpal complications. It is therefore of interest whether dentists perform one- or two-step incomplete excavation, and which criteria and methods they use to assess and provide removal of deep caries. This study investigated the attitudes and behaviour of dentists in northern Germany using a new, validated questionnaire. The survey included 2,346 practitioners, 821 (35%) of whom responded. Demographic and sensitivity analysis did not indicate selection bias. 50% of dentists considered only complete excavation, even if pulp exposure was likely. If caries was to be removed incompletely, 77% considered two-step excavation. Hardness was the most important criterion to assess excavation. To treat an exposed pulp, 75% of dentists considered direct capping, 70% refused incomplete excavation fearing caries progression or pulp damage, and 59% reported to prefer more invasive treatment to facilitate restoration longevity. Over 50% recognised an influence of professional regulations on their treatment decisions. There was a moderate correlation between attitudes and behaviour of dentists, with dentists who suspected residual caries to be harmful rejecting incomplete excavation and vice versa. Cluster analysis identified two groups of dentists with opposite attitudes and behaviour, independently from dentist's age or gender. In conclusion, the majority of surveyed dentists was sceptical about leaving caries during excavation and does not practice incomplete caries removal. Therefore, benefits of partial excavation should be highlighted in under- and postgraduate education and regulatory incentives modified to promote minimally invasive techniques. PMID:23899958

  17. Geophysical evidence for melt in the deep lunar interior and implications for lunar evolution

    NASA Astrophysics Data System (ADS)

    Khan, A.; Connolly, J. A. D.; Pommier, A.; Noir, J.

    2014-10-01

    Analysis of lunar laser ranging and seismic data has yielded evidence that has been interpreted to indicate a molten zone in the lowermost mantle overlying a fluid core. Such a zone provides strong constraints on models of lunar thermal evolution. Here we determine thermochemical and physical structure of the deep Moon by inverting lunar geophysical data (mean mass and moment of inertia, tidal Love number, and electromagnetic sounding data) in combination with phase-equilibrium computations. Specifically, we assess whether a molten layer is required by the geophysical data. The main conclusion drawn from this study is that a region with high dissipation located deep within the Moon is required to explain the geophysical data. This region is located within the mantle where the solidus is crossed at a depth of ˜1200 km (≥1600°C). Inverted compositions for the partially molten layer (150-200 km thick) are enriched in FeO and TiO2 relative to the surrounding mantle. The melt phase is neutrally buoyant at pressures of ˜4.5-4.6 GPa but contains less TiO2 (<15 wt %) than the Ti-rich (˜16 wt %) melts that produced a set of high-density primitive lunar magmas (density of 3.4 g/cm3). Melt densities computed here range from 3.25 to 3.45 g/cm3 bracketing the density of lunar magmas with moderate-to-high TiO2 contents. Our results are consistent with a model of lunar evolution in which the cumulate pile formed from crystallization of the magma ocean as it overturned, trapping heat-producing elements in the lower mantle.

  18. Deep-tow magnetic survey above large exhumed mantle domains of the eastern Southwest Indian ridge

    NASA Astrophysics Data System (ADS)

    Bronner, A.; Munschy, M.; Carlut, J. H.; Searle, R. C.; Sauter, D.; Cannat, M.

    2011-12-01

    The recent discovery of a new type of seafloor, the "smooth seafloor", formed with no or very little volcanic activity along the ultra-slow spreading Southwest Indian ridge (SWIR) shows an unexpected complexity in processes of generation of the oceanic lithosphere. There, detachment faulting is thought to be a mechanism for efficient exhumation of deep-seated mantle rocks. We present here a deep-tow geological-geophysical survey over smooth seafloor at the eastern SWIR (62-64°N) combining magnetic data, geology mapping from side-scan sonar images and results from dredge sampling. We introduce a new type of calibration approach for deep-tow fluxgate magnetometer. We show that magnetic data can be corrected from the magnetic effect of the vehicle with no recourse to its attitude (pitch, roll and heading) but only using the 3 components recorded by the magnetometer and an approximation of the scalar intensity of the Earth magnetic field. The collected dredge samples as well as the side-scan images confirm the presence of large areas of exhumed mantle-derived peridodites surrounded by a few volcanic constructions. This allows us to hypothesis that magnetic anomalies are caused by serpentinized peridotites or magmatic intrusions. We show that the magnetic signature of the smooth seafloor is clearly weaker than the surrounding volcanic areas. Moreover, the calculated magnetization of a source layer as well as the comparison between deep-tow and sea-surface magnetic data argue for strong East-West variability in the distribution of the magnetized sources. This variability may results from fluid-rocks interaction along the detachment faults as well as from the repartition of the volcanic material and thus questions the seafloor spreading origin of the corresponding magnetic anomalies. Finally, we provide magnetic arguments, as calculation of block rotation or spreading asymmetry in order to better constrain tectonic mechanisms that occur during the formation of this

  19. AzTEC/ASTE 1.1 mm Deep Surveys: Number Counts and Clustering of Millimeter-bright Galaxies

    NASA Astrophysics Data System (ADS)

    Hatsukade, B.; Kohno, K.; Aretxaga, I.; Austermann, J. E.; Ezawa, H.; Hughes, D. H.; Ikarashi, S.; Iono, D.; Kawabe, R.; Matsuo, H.; Matsuura, S.; Nakanishi, K.; Oshima, T.; Perera, T.; Scott, K. S.; Shirahata, M.; Takeuchi, T. T.; Tamura, Y.; Tanaka, K.; Tosaki, T.; Wilson, G. W.; Yun, M. S.

    2010-10-01

    We present number counts and clustering properties of millimeter-bright galaxies uncovered by the AzTEC camera mounted on the Atacama Submillimeter Telescope Experiment (ASTE). We surveyed the AKARI Deep Field South (ADF-S), the Subaru/XMM Newton Deep Field (SXDF), and the SSA22 fields with an area of ~0.25 deg2 each with an rms noise level of ~0.4-1.0 mJy. We constructed differential and cumulative number counts, which provide currently the tightest constraints on the faint end. The integration of the best-fit number counts in the ADF-S find that the contribution of 1.1 mm sources with fluxes >=1 mJy to the cosmic infrared background (CIB) at 1.1 mm is 12-16%, suggesting that the large fraction of the CIB originates from faint sources of which the number counts are not yet constrained. We estimate the cosmic star-formation rate density contributed by 1.1 mm sources with >=1 mJy using the best-fit number counts in the ADF-S and find that it is lower by about a factor of 5-10 compared to those derived from UV/optically-selected galaxies at z~2-3. The average mass of dark halos hosting bright 1.1 mm sources was calculated to be 1013-1014 Msolar. Comparison of correlation lengths of 1.1 mm sources with other populations and with a bias evolution model suggests that dark halos hosting bright 1.1 mm sources evolve into systems of clusters at present universe and the 1.1 mm sources residing the dark halos evolve into massive elliptical galaxies located in the center of clusters.

  20. Geophysical evidence for melt in the deep lunar interior and implications for lunar evolution (Invited)

    NASA Astrophysics Data System (ADS)

    Khan, A.; Connolly, J. A.; Pommier, A.

    2013-12-01

    Analysis of lunar seismic and lunar laser ranging data has yielded evidence that has been interpreted to indicate a molten zone in the lower-most mantle and/or the outer core of the Moon. Such a zone would provide strong constraints on models of the thermal evolution of the Moon. Here we invert lunar geophysical data in combination with phase-equilibrium modeling to derive information about the thermo-chemical and physical structure of the deep lunar interior. Specifically, we assess whether a molten layer is required by the geophysical data and, if so, its likely composition and physical properties (e.g., density and seismic wave speeds). The data considered are mean mass and moment of inertia, second-degree tidal Love number, and frequency-dependent electromagnetic sounding data. The main conclusion drawn from this study is that a region with high dissipation located deep within the Moon is indeed required to explain the geophysical data. If this dissipative region is located within the mantle, then the solidus is crossed at a depth of ~1200 km (>1600 deg C). The apparent absence of far-side deep moonquakes (DMQs) is supporting evidence for a highly dissipative layer. Inverted compositions for the partially molten layer (typically 100--200 km thick) are enriched in FeO and TiO2 relative to the surrounding mantle. While the melt phase in >95 % of inverted models is neutrally buoyant at pressures of ~4.5--4.6 GPa, the melt contains less TiO2 (>~4 wt %) than the Ti-rich (~16 wt % TiO2) melts that produced a set of high-density primitive lunar magmas (~3.4 g/ccm). Melt densities computed here range from 3.3 to 3.4 g/ccm bracketing the density of lunar magmas with moderate-to-high TiO2 contents. Our results are consistent with a model of lunar evolution in which the cumulate pile formed from crystallization of the magma ocean as it overturned, trapping heat-producing elements in the lower mantle.

  1. The Evolution of Technology in the Deep Space Network: A History of the Advanced Systems Program

    NASA Technical Reports Server (NTRS)

    Layland, J. W.; Rauch, L. L.

    1994-01-01

    The Deep Space Network (DSN) of 1995 might be described as the evolutionary result of 45 years of deep space communication and navigation, together with the synergistic activities of radio science and radar and radio astronomy. But the evolution of the DSN did not just happen - it was carefully planned and created. The evolution of the DSN has been an ongoing engineering activity, and engineering is a process of problem solving under constraints, one of which is technology. In turn, technology is the knowledge base providing the capability and experience for practical application of various areas of science, when needed. The best engineering solutions result from optimization under the fewest constraints, and if technology needs are well anticipated (ready when needed), then the most effective engineering solution is possible. Throughout the history of the DSN it has been the goal and function of DSN advanced technology development (designated the DSN Advanced Systems Program from 1963 through 1994) to supply the technology needs of the DSN when needed, and thus to minimize this constraint on DSN engineering. Technology often takes considerable time to develop, and when that happens, it is important to have anticipated engineering needs; at times, this anticipation has been by as much as 15 years. Also, on a number of occasions, mission malfunctions or emergencies have resulted in unplanned needs for technology that has, in fact, been available from the reservoir of advanced technology provided by the DSN Advanced Systems Program. Sometimes, even DSN engineering personnel fail to realize that the organization of JPL permits an overlap of DSN advanced technology activities with subsequent engineering activities. This can result in the flow of advanced technology into DSN engineering in a natural and sometimes almost unnoticed way. In the following pages, we will explore some of the many contributions of the DSN Advanced Systems Program that were provided to DSN

  2. The 2 Ms Chandra Deep Field-North Survey and the 250 ks Extended Chandra Deep Field-South Survey: Improved Point-source Catalogs

    NASA Astrophysics Data System (ADS)

    Xue, Y. Q.; Luo, B.; Brandt, W. N.; Alexander, D. M.; Bauer, F. E.; Lehmer, B. D.; Yang, G.

    2016-06-01

    We present improved point-source catalogs for the 2 Ms Chandra Deep Field-North (CDF-N) and the 250 ks Extended Chandra Deep Field-South (E-CDF-S) Surveys, implementing a number of recent improvements in Chandra source-cataloging methodology. For CDF-N/E-CDF-S, we provide a main catalog that contains 683/1003 X-ray sources detected with wavdetect at a false-positive probability threshold of 10‑5 that also satisfy a binomial-probability source-selection criterion of P\\lt 0.004/P < 0.002. Such an approach maximizes the number of reliable sources detected: a total of 196/275 main-catalog sources are new compared to the Alexander et al. CDF-N/Lehmer et al. E-CDF-S main catalogs. We also provide CDF-N/E-CDF-S supplementary catalogs that consist of 72/56 sources detected at the same wavdetect threshold and having P of 0.004–0.1/0.002–0.1 and {K}s≤slant 22.9/{K}s≤slant 22.3 mag counterparts. For all ≈ 1800 CDF-N and E-CDF-S sources, including the ≈ 500 newly detected ones (these being generally fainter and more obscured), we determine X-ray source positions utilizing centroid and matched-filter techniques; we also provide multiwavelength identifications, apparent magnitudes of counterparts, spectroscopic and/or photometric redshifts, basic source classifications, and estimates of observed active galactic nucleus and galaxy source densities around respective field centers. Simulations show that both the CDF-N and E-CDF-S main catalogs are highly reliable and reasonably complete. Background and sensitivity analyses indicate that the on-axis mean flux limits reached represent a factor of ≈ 1.5–2.0 improvement over the previous CDF-N and E-CDF-S limits. We make our data products publicly available.

  3. Surveying Galaxy Evolution in the Far-Infrared: A Far-Infrared All-Sky Survey Concept

    NASA Technical Reports Server (NTRS)

    Benford, D. J.; Amato, M. J.; Dwek, E.; Freund, M. M.; Gardner, J. P.; Kashlinsky, A.; Leisawitz, D. T.; Mather, J. C.; Moseley, S. H.; Shafer, R. A.

    2004-01-01

    Half of the total luminosity in the Universe is emitted at rest wavelengths approximately 80-100 microns. At the highest known galaxy redshifts (z greater than or equal to 6) this energy is redshifted to approximately 600 microns. Quantifying the evolution of galaxies at these wavelengths is crucial to our understanding of the formation of structure in the Universe following the big bang. Surveying the whole sky will find the rare and unique objects, enabling follow-up observations. SIRCE, the Survey of Infrared Cosmic Evolution, is such a mission concept under study at NASA's Goddard Space Flight Center. A helium-cooled telescope with ultrasensitive detectors can image the whole sky to the confusion limit in 6 months. Multiple wavelength bands permit the extraction of photometric redshifts, while a large telescope yields a low confusion limit. We discuss the implications of such a survey for galaxy formation and evolution, large-scale structure, star formation, and the structure of interstellar dust.

  4. Morphology of Florida escarpment chemosynthetic brine seep community sites: deep-tow, seabeam, and GLORIA surveys

    SciTech Connect

    Paull, C.K.; Spiess, F.N.; Curray, J.R.; Twitchell, D.

    1988-02-01

    The Florida Escarpment near 26/degree/N was surveyed with Deep-Tow, Seabeam, and GLORIA in the area where chemosynthetic communities were discovered via ALVIN in the abyssal Gulf of Mexico. Seabeam bathymetry and GLORIA images indicate that the escarpment is a generally straight cliff with average slopes of about 45/degree/ from 2200 to more than 3250 m. The escarpment's face is cut by 2-km wide box canyons whose head walls are as steep as the intervening escarpment's face. The shapes of these canyons are difficult to explain with the traditional models of canyon formation. Sidescan sonar images and bottom photographs reveal that the escarpment's face is composed of a series of long, straight bedding-plain terraces which are truncated along nearly vertical orthogonal joints. Exposure of these truncated strata indicate the face of the escarpment is eroded. The contact between the basal escarpment and the flat-lying abyssal hemipelagic sediments is abrupt. Basal talus is uncommon because the abyssal floor is part of the distal Mississippi fan which is rapidly burying the escarpment. However, where talus occurs, it is in tongues of angular megabreccia of meter- and larger-sized blocks which indicate periodic catastrophic collapse. Sidescan images reveal bands of contrast in the reflective texture of the sea floor that extends 10-20 m from the base along more than 10% of the surveyed area. Photographic surveys show that these areas are associated with communities of abundant organisms. Apparently chemosynthetic communities line extensive sections of the escarpment base where reduced brines seep out into the sea floor. The morphology suggests joints and deep seeps are controlling factors in scarp retreat.

  5. Deep sequencing identifies genetic heterogeneity and recurrent convergent evolution in chronic lymphocytic leukemia

    PubMed Central

    Ojha, Juhi; Ayres, Jackline; Secreto, Charla; Tschumper, Renee; Rabe, Kari; Van Dyke, Daniel; Slager, Susan; Shanafelt, Tait; Fonseca, Rafael; Kay, Neil E.

    2015-01-01

    Recent high-throughput sequencing and microarray studies have characterized the genetic landscape and clonal complexity of chronic lymphocytic leukemia (CLL). Here, we performed a longitudinal study in a homogeneously treated cohort of 12 patients, with sequential samples obtained at comparable stages of disease. We identified clonal competition between 2 or more genetic subclones in 70% of the patients with relapse, and stable clonal dynamics in the remaining 30%. By deep sequencing, we identified a high reservoir of genetic heterogeneity in the form of several driver genes mutated in small subclones underlying the disease course. Furthermore, in 2 patients, we identified convergent evolution, characterized by the combination of genetic lesions affecting the same genes or copy number abnormality in different subclones. The phenomenon affects multiple CLL putative driver abnormalities, including mutations in NOTCH1, SF3B1, DDX3X, and del(11q23). This is the first report documenting convergent evolution as a recurrent event in the CLL genome. Furthermore, this finding suggests the selective advantage of specific combinations of genetic lesions for CLL pathogenesis in a subset of patients. PMID:25377784

  6. Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY FIELD: PHOTOMETRIC CANDIDATES AND LUMINOSITY FUNCTION

    SciTech Connect

    Ota, Kazuaki; Ouchi, Masami; Iye, Masanori; Kashikawa, Nobunari; Kobayashi, Masakazu A. R.; Morokuma, Tomoki; Furusawa, Hisanori; Shimasaku, Kazuhiro; Totani, Tomonori; Nagashima, Masahiro; Harayama, Atsushi; Kodaka, Natsuki; Tajitsu, Akito; Hattori, Takashi

    2010-10-10

    We conducted a deep narrowband NB973 (FWHM = 200 A centered at 9755 A) survey of z = 7 Ly{alpha} emitters (LAEs) in the Subaru/XMM-Newton Deep Survey Field, using the fully depleted CCDs newly installed on the Subaru Telescope Suprime-Cam, which is twice more sensitive to z = 7 Ly{alpha} at {approx}1 {mu}m than the previous CCDs. Reaching the depth 0.5 mag deeper than our previous survey in the Subaru Deep Field that led to the discovery of a z = 6.96 LAE, we detected three probable z = 7 LAE candidates. Even if all the candidates are real, the Ly{alpha} luminosity function (LF) at z = 7 shows a significant deficit from the LF at z = 5.7 determined by previous surveys. The LAE number and Ly{alpha} luminosity densities at z = 7 are {approx}7.7%-54% and {approx}5.5%-39%, respectively, of those at z = 5.7, to the Ly{alpha} line luminosity limit of L(Ly{alpha}) {approx}> 9.2 x 10{sup 42} erg s{sup -1}. This could be due to evolution of the LAE population at these epochs as a recent galaxy evolution model predicts that the LAE modestly evolves from z = 5.7 to 7. However, even after correcting for this effect of galaxy evolution on the decrease in LAE number density, the z = 7 Ly{alpha} LF still shows a deficit from z = 5.7 LF. This might reflect the attenuation of Ly{alpha} emission by neutral hydrogen remaining at the epoch of reionization and suggests that reionization of the universe might not be complete yet at z = 7. If we attribute the density deficit to reionization, the intergalactic medium transmission for Ly{alpha} photons at z = 7 would be 0.4 {<=} T {sup IGM}{sub Ly{alpha} {<=}} 1, supporting the possible higher neutral fraction at the earlier epochs at z > 6 suggested by the previous surveys of z = 5.7-7 LAEs, z {approx} 6 quasars, and z > 6 gamma-ray bursts.

  7. Correlation of deep moonquakes and mare basalts: Implications for lunar mantle structure and evolution

    NASA Astrophysics Data System (ADS)

    Qin, Chuan; Muirhead, Alicia C.; Zhong, Shijie

    2012-07-01

    The genesis of mare basalts and deep moonquakes are important events that have major implications for understanding the thermal evolution and interior dynamics of the Moon. The eruption of mare basalts predominantly from 3.9 Ga to 3 Ga ago represents one of the most important events in lunar geological history. Deep moonquakes recorded by the Apollo Seismic Network show the dynamic nature of the present-day lunar mantle. In this study, we have correlated the presence of the mare basalts, using FeO concentration as a proxy, with the epicenters of 52 well-located deep moonquake (DMQ) clusters. We determine FeO concentrations of 13 wt.% or higher to be representative of the mare basalt deposits. Our analysis shows that over 63% of the DMQs occur within 1° from the mare basalt deposits, while over 80% of the DMQs are within 5° from the mare basalt deposits. Our analysis also shows that for the same amount of randomly distributed DMQs within a spherical cap on the nearside that encompasses all the nearside DMQs, the probability of over 80% of the DMQs occurring within 5° from the mare basalt deposits is about 0.01, thus rejecting a random distribution of the DMQs with respect to the mare basalts. The correlation between mare basalts and the DMQs from our analysis suggests that the mare basalts may be derived from melting processes at relatively large depths, consistent with previous petrology and geodynamic studies. We propose that the water and volatiles in the mare basalt source material (i.e., a mixture of ilmenite cumulates and olivine orthopyroxene, together called MIC) play an important role in causing the DMQs and that the DMQs delineate the present-day locations of MIC in the deep mantle. Since the mare basalts are predominately distributed on the nearside, our results further suggest that the DMQs may indeed be largely nearside features, which is a prediction that can be tested in future lunar seismic exploration.

  8. INTEGRAL/IBIS deep extragalactic survey: M81, LMC and 3C 273/Coma fields

    NASA Astrophysics Data System (ADS)

    Mereminskiy, Ilya A.; Krivonos, Roman A.; Lutovinov, Alexander A.; Sazonov, Sergey Yu.; Revnivtsev, Mikhail G.; Sunyaev, Rashid A.

    2016-06-01

    We present results of a deep survey of three extragalactic fields, M81 (exposure of 9.7 Ms), Large Magellanic Cloud (6.8 Ms) and 3C 273/Coma (9.3 Ms), in the hard X-ray (17-60 keV) energy band with the IBIS telescope onboard the INTEGRAL observatory, based on 12 years of observations (2003-2015). The combined survey reaches a 4σ peak sensitivity of 0.18 mCrab (2.6 × 10-12 erg s-1 cm-2) and sensitivity better than 0.25 and 0.87 mCrab over 10 per cent and 90 per cent of its full area of 4900 deg2, respectively. We have detected in total 147 sources at S/N > 4σ, including 37 sources observed in hard X-rays for the first time. The survey is dominated by extragalactic sources, mostly active galactic nuclei (AGN). The sample of identified sources contains 98 AGN (including 64 Seyfert galaxies, seven low-ionization nuclear emission-line region galaxies, three X-ray bright optically normal galaxies, 16 blazars and eight AGN of unclear optical class), two galaxy clusters (Coma and Abell 3266), 17 objects located in the Large and Small Magellanic Clouds (13 high- and two low-mass X-ray binaries and two X-ray pulsars), three Galactic cataclysmic variables, one ultraluminous X-ray source (M82 X-1) and one blended source (SWIFT J1105.7+5854). The nature of 25 sources remains unknown, so that the survey's identification is currently complete at 83 per cent. We have constructed AGN number-flux relations (log N-log S) and calculated AGN number densities in the local Universe for the entire survey and for each of the three extragalactic fields.

  9. Spectroscopic identification of a redshift 1.55 supernova host galaxy from the Subaru Deep Field Supernova Survey

    NASA Astrophysics Data System (ADS)

    Frederiksen, Teddy F.; Graur, Or; Hjorth, Jens; Maoz, Dan; Poznanski, Dovi

    2014-03-01

    Context. The Subaru Deep Field (SDF) Supernova Survey discovered ten Type Ia supernovae (SNe Ia) in the redshift range 1.5 < z < 2.0, determined solely from photometric redshifts of the host galaxies. However, photometric redshifts might be biased, and the SN sample could be contaminated by active galactic nuclei (AGNs). Aims: We aim to obtain the first robust redshift measurement and classification of a z > 1.5 SDF SN Ia host galaxy candidate. Methods: We use the X-shooter (U-to-K-band) spectrograph on the Very Large Telescope to allow the detection of different emission lines in a wide spectral range. Results: We measure a spectroscopic redshift of 1.54563 ± 0.00027 of hSDF0705.25, consistent with its photometric redshift of 1.552 ± 0.018. From the strong emission-line spectrum we rule out AGN activity, thereby confirming the optical transient as a SN. The host galaxy follows the fundamental metallicity relation showing that the properties of this high-redshift SN Ia host galaxy is similar to other field galaxies. Conclusions: Spectroscopic confirmation of additional SDF SN hosts would be required to confirm the cosmic SN rate evolution measured in the SDF. Based on observations made with ESO telescopes at the La Silla Paranal Observatory under program ID 089.A-0739.

  10. The Galaxy Evolution Explorer (GALEX). Its legacy of UV surveys, and science highlights

    NASA Astrophysics Data System (ADS)

    Bianchi, Luciana

    2014-11-01

    The Galaxy Evolution Explorer (GALEX) imaged the sky in the Ultraviolet (UV) for almost a decade, delivering the first sky surveys at these wavelengths. Its database contains far-UV (FUV, λ eff˜1528 Å) and near-UV (NUV, λ eff˜2310 Å) images of most of the sky, including deep UV-mapping of extended galaxies, over 200 million source measurements, and more than 100,000 low-resolution UV spectra. The GALEX archive will remain a long-lasting resource for statistical studies of hot stellar objects, QSOs, star-forming galaxies, nebulae and the interstellar medium. It provides an unprecedented road-map for planning future UV instrumentation and follow-up observing programs in the UV and at other wavelengths. We review the characteristics of the GALEX data, and describe final catalogs and available tools, that facilitate future exploitation of this database. We also recall highlights from the science results uniquely enabled by GALEX data so far.

  11. Geophysical Survey To Understand Failure Mechanisms Involved On Deep Seated Landslides

    NASA Astrophysics Data System (ADS)

    Lebourg, T.; Tric, E.; Guglielmi, Y.; Cappa, F.; Charmoille, A.; Bouissou, S.

    2003-04-01

    The understanding of rupture processes involve on deep seated landslides and hence the prediction of such phenomenon is difficult for two main reasons. The first one, arise from the difficulty in estimating the mechanical behaviour of the whole mountain which is very different from that of a rock sample we can study on laboratory. This is mainly true in the upper part of slope subjected to weathering (Lebourg and al., 2002). The second reason, is due to the necessity of taking into account both the 3D geometry of the phenomenon and geological discontinuities affecting the mountain slide. We propose to show geophysical research on a deep seated landslide and the way we use to integreted then into numerical models. One of main problem of study deep seatted landslides with geophysical survey is the size of the landslide and the deep of the slope. The landslides we studied are located in the French Alps (Clapière landslide and Rocbillière landslide). It concern various geological formation, triggered by hydrological sollicitations. Our geophysical methods allow us to obtain 2D and 3D imagery of the geological structures, but also the shearing surface and the hydrological system used in the numerical and physical modeling. The research of the hydrogeological system can become one of the must importante result for the administration. After the first geophysical survey, we can quantify the hydrogeological level who can initiate or accelerate the paroxism of the landslide. Numerical model and prediction can also propose a 'surveillance' on the geophysical pseudo-dynamic prospecting. Our results showed also the importance of the weathering and the complexe chenalisation of the water whithin the slope, in the initiation of the movement. Our futur goal is to study the relative influence of the mechanical behaviour of the mountain, the behaviour of the wheathering zone, faults and intial topography of the mountain on landslide to determine the key parameter controlling this

  12. A very deep IRAS survey at l(II) = 97 deg, b(II) = +30 deg

    NASA Technical Reports Server (NTRS)

    Hacking, Perry; Houck, James R.

    1987-01-01

    A deep far-infrared survey is presented using over 1000 scans made of a 4 to 6 sq. deg. field at the north ecliptic pole by the IRAS. Point sources from this survey are up to 100 times fainter than the IRAS point source catalog at 12 and 25 micrometers, and up to 10 times fainter at 60 and 100 micrometers. The 12 and 25 micrometer maps are instrumental noise-limited, and the 60 and 100 micrometer maps are confusion noise-limited. The majority of the 12 micrometer point sources are stars within the Milky Way. The 25 micrometer sources are composed almost equally of stars and galaxies. About 80% of the 60 micrometer sources correspond to galaxies on Palomar Observatory Sky Survey (POSS) enlargements. The remaining 20% are probably galaxies below the POSS detection limit. The differential source counts are presented and compared with what is predicted by the Bahcall and Soneira Standard Galaxy Model using the B-V-12 micrometer colors of stars without circumstellar dust shells given by Waters, Cote and Aumann. The 60 micrometer source counts are inconsistent with those predicted for a uniformly distributed, nonevolving universe. The implications are briefly discussed.

  13. A skewer survey of the Galactic halo from deep CFHT and INT images

    NASA Astrophysics Data System (ADS)

    Pila-Díez, B.; de Jong, J. T. A.; Kuijken, K.; van der Burg, R. F. J.; Hoekstra, H.

    2015-07-01

    We study the density profile and shape of the Galactic halo using deep multicolour images from the MENeaCS and CCCP projects, over 33 fields selected to avoid overlap with the Galactic plane. Using multicolour selection and point spread function homogenization techniques we obtain catalogues of F stars (near-main sequence turnoff stars) out to Galactocentric distances up to 60 kpc. Grouping nearby lines of sight, we construct the stellar density profiles through the halo in eight different directions by means of photometric parallaxes. Smooth halo models are then fitted to these profiles. We find clear evidence for a steepening of the density profile power law index around R = 20 kpc, from -2.50 ± 0.04 to -4.85 ± 0.04, and for a flattening of the halo towards the poles with best-fit axis ratio 0.79 ± 0.02. Furthermore, we cannot rule out a mild triaxiality (w ≥ 0.88 ± 0.07). We recover the signatures of well-known substructure and streams that intersect our lines of sight. These results are consistent with those derived from wider but shallower surveys, and augur well for upcoming, wide-field surveys of comparable depth to our pencil beam surveys.

  14. Search for cosmic strings in the Great Observatories Origins Deep Survey

    SciTech Connect

    Christiansen, J. L.; Albin, E.; James, K. A.; Goldman, J.; Maruyama, D.; Smoot, G. F.

    2008-06-15

    We search Hubble Space Telescope Treasury Program images collected as part of the Great Observatories Origins Deep Survey for pairs of galaxies consistent with the gravitational lensing signature of a cosmic string. Our technique includes estimates of the efficiency for finding the lensed galaxy pair. In the north (south) survey field we find no evidence out to a redshift of greater than 0.5 (0.3) for cosmic strings to a mass per unit length limit of G{mu}/c{sup 2}<3.0x10{sup -7} at 95% confidence limits (C.L.). In the combined 314.9 arcmin{sup 2} of the north and south survey fields this corresponds to a global limit on {omega}{sub strings}<0.02. Our limit on G{mu}/c{sup 2} is more than an order of magnitude lower than searches for individual strings in cosmic microwave background (CMB) data. Our limit is higher than other CMB and gravitational wave searches, however, we note that it is less model dependent than these other searches.

  15. New insights on the deep structure and evolution of the Gibraltar Arc System and Atlas Mountains: results from TOPOMED-TOPOEUROPE Project

    NASA Astrophysics Data System (ADS)

    Fernandez, Manel; Jones, Alan G.; Grevemeyer, Ingo; Terrinha, Pedro; Faccenna, Claudio; Wortel, Rinus; Topomed Team

    2013-04-01

    One of the target areas of the TOPO-MED CRP within the ESF TOPO-EUROPE EUROCORES Project is the westernmost Mediterranean region, which includes the Gibraltar Arc System (Betic-Rif orogen, Guadalquivir and Rharb foreland basins, Alboran back-arc basin and Gulf of Cadiz imbricated accretionary wedge) and the Atlas Mountains (High and Middle Atlas). Within this framework, several geological and geophysical surveys have been carried out including, among others, a 6-month deployment of OBSes in the Gulf of Cadiz and the Alboran basin, active seismic surveys combining MCS and OBS along five profiles on the Alboran and Algerian basins, a wide angle seismic profile across the Atlas Mountains, a deep MCS survey on the Alboran basin and the Gulf of Cadiz totaling 2560 km, a high resolution seismic survey on the Alboran basin, a back-scatter and high resolution topography survey on the Alboran Basin and several MT profiles across the Atlas mountains. The results of these surveys - some of them still preliminary and under processing - together with integrated models allow us to better define the geometries and properties of the crust and upper mantle structures and to link them with surface processes and the geodynamic evolution of the region. Outstanding results are the large crustal thickness variations between the Betic-Rif orogen and the Alboran basin, the very moderate crustal root beneath the Atlas Mountains and a conspicuous crust/mantle strain partitioning affecting most of the region. These results, together with those coming from the TOPO-IBERIA Spanish project, have allowed to propose different geodynamic models to explain the tectonic evolution of the region where the leading mechanism implies twisted mantle slab roll-back. In addition, modeling the Messinian salinity crisis including both the closure of the Mediterranean and desiccation and the re-opening and flooding have also been proposed.

  16. VLA high resolution observations of weak Leiden-Berkeley Deep-Survey (LBDS) sources

    NASA Astrophysics Data System (ADS)

    Oort, M. J. A.; Katgert, P.; Steeman, F. W. M.; Windhorst, R. A.

    1987-06-01

    The majority of the 1-arcsec resolution snapshot maps of 133 radio sources presented from the Leiden-Berkeley Deep Survey (LBDS) indicate that the sources have flux densities in the 1-100 mJy range at 1.4 GHz, with a median flux density of 5 mJy. A combination of all radio-morphological data available for the LBDS, the median angular size of a complete radio sample is found to decrease with decreasing flux density to a value as low as about 2 arcsec between 1 and 10 mJy. Definite indications are found for a decrease of intrinsic size with increasing redshift, with a relation that results in a size decrease of factor 4 with respect to the local value at the same radio power.

  17. Photometric identification of objects from Galaxy Evolution Explorer Survey and Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Preethi, K.; Gudennavar, S. B.; Bubbly, S. G.; Murthy, Jayant; Brosch, Noah

    2014-01-01

    We have used Galaxy Evolution Explorer (GALEX) and Sloan Digital Sky Survey (SDSS) observations to extract seven band photometric magnitudes for over 80 000 objects in the vicinity of the North Galactic Pole. Although these had been identified as stars by the SDSS pipeline, we found through fitting with model spectral energy distributions that most were, in fact, of extragalactic origin. Only about 9 per cent of these objects turned out to be main-sequence stars and about 11 per cent were white dwarfs and red giants collectively, while galaxies and quasars contributed to the remaining 80 per cent of the data. We have classified these objects into different spectral types (for the stars) and into different galactic types (for the galaxies). As part of our fitting procedure, we derive the distance and extinction to each object and the photometric redshift towards galaxies and quasars. This method easily allows for the addition of any number of observations to cover a more diverse range of wavelengths, as well as the addition of any number of model templates. The primary objective of this work is to eventually derive a three-dimensional extinction map of the Milky Way Galaxy.

  18. MOIRCS DEEP SURVEY. III. ACTIVE GALACTIC NUCLEI IN MASSIVE GALAXIES AT z = 2-4

    SciTech Connect

    Yamada, T.; Kajisawa, M.; Akiyama, M.; Ichikawa, T.; Tokoku, C.; Yoshikawa, T.; Konishi, M.; Nishimura, T.; Omata, K.; Suzuki, R.; Tanaka, I.; Uchimoto, Y. K.

    2009-07-10

    We investigate the X-ray properties of the K-band-selected galaxies at redshift 2 < z < 4 by using our deep near-infrared images obtained in the Multi-Object Infrared Camera and Spectrograph Deep Survey project and the published Chandra X-ray source catalog. Sixty-one X-ray sources with the 2-10 keV luminosity L{sub X} = 10{sup 42}-10{sup 44} erg s{sup -1} are identified with the K-selected galaxies and we found that they are exclusively (90%) associated with the massive objects with a stellar mass larger than 10{sup 10.5} M{sub sun}. Our results are consistent with the idea that the M {sub BH}/M{sub str} ratio of the galaxies at z = 2-4 is similar to the present-day value. On the other hand, the active galactic nucleus (AGN) detection rate among the very massive galaxies with a stellar mass larger than 10{sup 11} M{sub sun} is high, 33% (26/78). They are active objects in the sense that the black hole mass accretion rate is {approx}1%-50% of the Eddington limit if they indeed have similar M {sub BH}/M {sub str} ratio with those observed in the local universe. The active duration in the AGN duty cycle of the high-redshift massive galaxies seems large.

  19. Shear wave velocity analysis of a deep seated gravel landslide structure using the microtremor survey method

    NASA Astrophysics Data System (ADS)

    Su, L.; Xu, X.; Liao, H.; Geng, X.-Y.

    2015-09-01

    The depth and geometry of potential failure surface is the fundamental for evaluating the mechanisms of a landslide. Traditional techniques to acquire information on potential sliding surface are mainly drilling, pitting, and trenching, but these techniques are time consuming and expensive. In this study, microtremor signals and the dispersion curves of surface wave are extracted from the vertical component of microtremor records using the spatial autocorrelation (SPAC) method to estimate shear wave velocity structure. The results suggest that the buried depth of phyllite bedrock is approximately 47.4m, and the thickness of weathered bedrock layer is about 9.9m at about 57.3m deep, which could be interpreted as the potential sliding surface of this landslide, in accordance with borehole data. The microtremor survey method (MSM) is flexible, non-invasive, relatively quick and deployable on the landslide. It clearly demonstrat that it is an effective tool to improve the drilling success rate, and hence allow a large scale and high density investigation of structure characteristics of a deep seated landslide.

  20. Cosmic Shear Results from the Deep Lens Survey. II. Full Cosmological Parameter Constraints from Tomography

    NASA Astrophysics Data System (ADS)

    Jee, M. James; Tyson, J. Anthony; Hilbert, Stefan; Schneider, Michael D.; Schmidt, Samuel; Wittman, David

    2016-06-01

    We present a tomographic cosmic shear study from the Deep Lens Survey (DLS), which, providing a limiting magnitude {r}{lim}∼ 27 (5σ ), is designed as a precursor Large Synoptic Survey Telescope (LSST) survey with an emphasis on depth. Using five tomographic redshift bins, we study their auto- and cross-correlations to constrain cosmological parameters. We use a luminosity-dependent nonlinear model to account for the astrophysical systematics originating from intrinsic alignments of galaxy shapes. We find that the cosmological leverage of the DLS is among the highest among existing \\gt 10 deg2 cosmic shear surveys. Combining the DLS tomography with the 9 yr results of the Wilkinson Microwave Anisotropy Probe (WMAP9) gives {{{Ω }}}m={0.293}-0.014+0.012, {σ }8={0.833}-0.018+0.011, {H}0={68.6}-1.2+1.4 {\\text{km s}}-1 {{{Mpc}}}-1, and {{{Ω }}}b=0.0475+/- 0.0012 for ΛCDM, reducing the uncertainties of the WMAP9-only constraints by ∼50%. When we do not assume flatness for ΛCDM, we obtain the curvature constraint {{{Ω }}}k=-{0.010}-0.015+0.013 from the DLS+WMAP9 combination, which, however, is not well constrained when WMAP9 is used alone. The dark energy equation-of-state parameter w is tightly constrained when baryonic acoustic oscillation (BAO) data are added, yielding w=-{1.02}-0.09+0.10 with the DLS+WMAP9+BAO joint probe. The addition of supernova constraints further tightens the parameter to w=-1.03+/- 0.03. Our joint constraints are fully consistent with the final Planck results and also with the predictions of a ΛCDM universe.

  1. Cosmic Shear Results from the Deep Lens Survey. II. Full Cosmological Parameter Constraints from Tomography

    NASA Astrophysics Data System (ADS)

    Jee, M. James; Tyson, J. Anthony; Hilbert, Stefan; Schneider, Michael D.; Schmidt, Samuel; Wittman, David

    2016-06-01

    We present a tomographic cosmic shear study from the Deep Lens Survey (DLS), which, providing a limiting magnitude {r}{lim}˜ 27 (5σ ), is designed as a precursor Large Synoptic Survey Telescope (LSST) survey with an emphasis on depth. Using five tomographic redshift bins, we study their auto- and cross-correlations to constrain cosmological parameters. We use a luminosity-dependent nonlinear model to account for the astrophysical systematics originating from intrinsic alignments of galaxy shapes. We find that the cosmological leverage of the DLS is among the highest among existing \\gt 10 deg2 cosmic shear surveys. Combining the DLS tomography with the 9 yr results of the Wilkinson Microwave Anisotropy Probe (WMAP9) gives {{{Ω }}}m={0.293}-0.014+0.012, {σ }8={0.833}-0.018+0.011, {H}0={68.6}-1.2+1.4 {\\text{km s}}-1 {{{Mpc}}}-1, and {{{Ω }}}b=0.0475+/- 0.0012 for ΛCDM, reducing the uncertainties of the WMAP9-only constraints by ˜50%. When we do not assume flatness for ΛCDM, we obtain the curvature constraint {{{Ω }}}k=-{0.010}-0.015+0.013 from the DLS+WMAP9 combination, which, however, is not well constrained when WMAP9 is used alone. The dark energy equation-of-state parameter w is tightly constrained when baryonic acoustic oscillation (BAO) data are added, yielding w=-{1.02}-0.09+0.10 with the DLS+WMAP9+BAO joint probe. The addition of supernova constraints further tightens the parameter to w=-1.03+/- 0.03. Our joint constraints are fully consistent with the final Planck results and also with the predictions of a ΛCDM universe.

  2. Constraining the temporal evolution of a deep hypersaline anoxic basin by 1D geochemical modelling

    NASA Astrophysics Data System (ADS)

    Goldhammer, Tobias; Aiello, Ivano; Zabel, Matthias

    2014-05-01

    Deep hypersaline anoxic basins (DHABs) are seafloor features of the accretionary prism of the Mediterranean Ridge. They have formed by the dissolution of exhumed shallow Messinian evaporites and subsequent concentration of the ultra-saline solutions in depressions on the seafloor. As an example, the horseshoe-shaped Urania basin is a DHAB south of the Peloponnese peninsula contains one of the most saline (about six times higher than Mediterranean seawater) and sulfidic (up to 15mM) water bodies of the Earth. Furthermore, its deepest part is underlain by a mud volcano that is responsible for the injection of fluid mud beneath the brine lake, with exceptionally sharp chemoclines between water column, brine, and mud layer. We here present a model approach to reconstruct the temporal aspects of the formation, dynamics and persistence of the brine-mud-system in the deep pit of the Urania Basin. Based on data from a sampling campaign with RV Meteor (Cruise M84/1 in February 2011), we set up a one-dimensional geochemical model that integrates diffusion, reaction and advective transport and mixing. Using a set of model preconditions, we aimed to answer (1) which processes are required to maintain the current situation of steep chemical gradients of the brine-mud-system, (2) how fast the current situation could have developed under different scenarios, and (3) how long such extraordinary conditions could have persisted through Earth's history. We further discuss the consequences of the temporal framework for the evolution of prokaryotic life in this extreme habitat.

  3. The Chandra Deep Survey of the Hubble Deep Field-North Area. II. Results from the Caltech Faint Field Galaxy Redshift Survey Area

    NASA Astrophysics Data System (ADS)

    Hornschemeier, A. E.; Brandt, W. N.; Garmire, G. P.; Schneider, D. P.; Barger, A. J.; Broos, P. S.; Cowie, L. L.; Townsley, L. K.; Bautz, M. W.; Burrows, D. N.; Chartas, G.; Feigelson, E. D.; Griffiths, R. E.; Lumb, D.; Nousek, J. A.; Ramsey, L. W.; Sargent, W. L. W.

    2001-06-01

    A deep X-ray survey of the Hubble Deep Field-North (HDF-N) and its environs is performed using data collected by the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-Ray Observatory. Currently a 221.9 ks exposure is available, the deepest ever presented, and here we give results on X-ray sources located in the 8.6‧×8.7‧ area covered by the Caltech Faint Field Galaxy Redshift Survey (the ``Caltech area''). This area has (1) deep photometric coverage in several optical and near-infrared bands; (2) extensive coverage at radio, submillimeter, and mid-infrared wavelengths; and (3) some of the deepest and most complete spectroscopic coverage ever obtained. It is also where the X-ray data have the greatest sensitivity; the minimum detectable fluxes in the 0.5-2 keV (soft) and 2-8 keV (hard) bands are ~1.3×10-16 and ~6.5×10-16 ergs cm-2 s-1, respectively. More than ~80% of the extragalactic X-ray background in the hard band is resolved. The 82 Chandra sources detected in the Caltech area are correlated with more than 25 multiwavelength source catalogs, and the results of these correlations as well as spectroscopic follow-up results obtained with the Keck and Hobby-Eberly Telescopes are presented. All but nine of the Chandra sources are detected optically with R<~26.5. Redshifts are available for 39% of the Chandra sources, including 96% of the sources with R<23 the redshift range is 0.1-3.5, with most sources having z<1.5. Eight of the X-ray sources are located in the HDF-N itself, including two not previously reported. A population of X-ray faint, optically bright, nearby galaxies emerges at soft-band fluxes of <~3×10-16 ergs cm-2 s-1. Our multiwavelength correlations have set the tightest constraints to date on the X-ray emission properties of μJy radio sources, mid-infrared sources detected by the Infrared Space Observatory (ISO), and very red (R-Ks>5.0) objects. A total of 16 of the 67 1.4 GHz μJy sources in the Caltech area are detected in the

  4. Wide-Field Imaging of the Hubble Deep Field-South Region. II. The Evolution of Galaxy Clustering at z < 1

    NASA Astrophysics Data System (ADS)

    Teplitz, Harry I.; Hill, Robert S.; Malumuth, Eliot M.; Collins, Nicholas R.; Gardner, Jonathan P.; Palunas, Povilas; Woodgate, Bruce E.

    2001-02-01

    We present the galaxy-galaxy angular correlations as a function of photometric redshift in a deep, wide galaxy survey centered on the Hubble Deep Field-South (HDF-S). Images were obtained with the Big Throughput Camera on the Blanco 4 m telescope at CTIO, of 1/2 square degree in broadband uBVRI, reaching ~24 mag. Approximately 40,000 galaxies are detected in the survey. We determine photometric redshifts using galaxy template fitting to the photometry. Monte Carlo simulations show that redshifts from these data should be reliable out to z~1, where the 4000 Å break shifts into the I band. The inferred redshift distribution, n(z), shows good agreement with the distribution of galaxies measured in the Hubble Deep Field-North (HDF-N) and the Canada-France Redshift Survey. After assigning galaxies to redshift bins with width Δz=0.33, we determine the two-point angular correlation function in each bin. We find that the amplitude of the correlation, Aw, drops across the three bins to redshift z~1. Simple ɛ models of clustering evolution fit this result, with the best agreement for ɛ=0. Hierarchical cold dark matter models best fit in a low-density, Λ-dominated universe. Based on observations obtained at Cerro Tololo Inter-American Observatory, a division of the National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.

  5. Stirring by deep cyclones and the evolution of Denmark strait overflow water observed at line W

    NASA Astrophysics Data System (ADS)

    Andres, M.; Toole, J. M.; Torres, D. J.; Smethie, W. M.; Joyce, T. M.; Curry, R. G.

    2016-03-01

    Shipboard velocity and water property data from 18 transects across the North Atlantic Deep Western Boundary Current (DWBC) near 40 °N are examined to study the evolution of the Denmark Strait Overflow Water (DSOW) component of the DWBC and mixing between DSOW and the interior. The examined transects along Line W - which stretches from the continental shelf south of New England to Bermuda - were made between 1994 and 2014. The shipboard data comprise measurements at regular stations of velocity from lowered acoustic Doppler current profilers, CTD profiles and trace gas chlorofluorocarbon (CFC) concentrations from bottle samples at discrete depths. Comparison of the Line W velocity sections with concurrent sea surface height maps from satellite altimetry indicates that large cyclones in the deep ocean accompany intermittent quasi-stationary meander troughs in the Gulf Stream path at Line W. A composite of 5 velocity sections along Line W suggests that a typical cyclone reaches swirl speeds of greater than 30 cm s-1 at 3400-m depth and has a radius (distance between the center and the maximum velocity) of 75 km. Tracer data suggest that these cyclones affect not only the deep velocity structure along Line W, but also provide a mechanism for water exchange between the DWBC's DSOW and the interior. Vigorous exchange is corroborated by a mismatch in the CFC-11:CFC-12 and CFC-113:CFC-12 ratio ages calculated for DSOW at Line W. During the most recent 5-year period (2010-2014), a decrease in DSOW density has been driven by warming (increasing by almost 0.1 °C) as salinity has increased only slightly (by 0.003, which is close to the 0.002 uncertainty of the measurements). The abyssal ocean offshore of the DWBC and Gulf Stream and deeper than 3000-m depth has freshened at a rate of 6×10-4 yr-1 since at least 2003. Density here remains nearly unchanged over this period, due to temperature compensation, though a linear cooling trend in the abyssal ocean (to compensate the

  6. Evolution and Functional Characterisation of Melanopsins in a Deep-Sea Chimaera (Elephant Shark, Callorhinchus milii)

    PubMed Central

    Davies, Wayne I. L.; Tay, Boon-Hui; Zheng, Lei; Danks, Janine A.; Brenner, Sydney; Foster, Russell G.; Collin, Shaun P.; Hankins, Mark W.; Venkatesh, Byrappa; Hunt, David M.

    2012-01-01

    Non-visual photoreception in mammals is primarily mediated by two splice variants that derive from a single melanopsin (OPN4M) gene, whose expression is restricted to a subset of retinal ganglion cells. Physiologically, this sensory system regulates the photoentrainment of many biological rhythms, such as sleep via the melatonin endocrine system and pupil constriction. By contrast, melanopsin exists as two distinct lineages in non-mammals, opn4m and opn4x, and is broadly expressed in a wide range of tissue types, including the eye, brain, pineal gland and skin. Despite these findings, the evolution and function of melanopsin in early vertebrates are largely unknown. We, therefore, investigated the complement of opn4 classes present in the genome of a model deep-sea cartilaginous species, the elephant shark (Callorhinchus milii), as a representative vertebrate that resides at the base of the gnathostome (jawed vertebrate) lineage. We reveal that three melanopsin genes, opn4m1, opn4m2 and opn4x, are expressed in multiple tissues of the elephant shark. The two opn4m genes are likely to have arisen as a result of a lineage-specific duplication, whereas “long” and “short” splice variants are generated from a single opn4x gene. By using a heterologous expression system, we suggest that these genes encode functional photopigments that exhibit both “invertebrate-like” bistable and classical “vertebrate-like” monostable biochemical characteristics. We discuss the evolution and function of these melanopsin pigments within the context of the diverse photic and ecological environments inhabited by this chimaerid holocephalan, as well as the origin of non-visual sensory systems in early vertebrates. PMID:23251480

  7. Evolution of deep-water rifted margins: Testing depth-dependent extensional models

    NASA Astrophysics Data System (ADS)

    Crosby, A. G.; White, N. J.; Edwards, G. R. H.; Thompson, M.; Corfield, R.; Mackay, L.

    2011-02-01

    A general understanding of rifted margins, which form by thinning of the continental lithosphere, exists. Nevertheless, the exact form of thinning is unclear. This debate has been stimulated by acquisition of dense seismic wide-angle and deep reflection surveys from Atlantic Ocean margins. A central issue concerns the way in which thinning changes with depth. We have tackled this issue by developing a generalized inverse model. This model attempts to fit subsidence and crustal thinning observations by varying strain rate as a function of time and space. Depth-dependent thinning is permitted but we do not prescribe its existence or form. Here, the algorithm is applied to six margins, including two of the most contentious conjugate margins: Newfoundland-Iberia and Brazil-Angola. Calculated strain rate histories predict thinning estimates which broadly match estimates inferred from normal faulting. The Eastern Indian and Beaufort Sea margins formed by largely uniform lithospheric thinning. In contrast, the Newfoundland-Iberian conjugate margins formed by a pattern of strongly depth-dependent strain rate. To account for the paucity of syn-rift decompression melting of the underlying asthenosphere, the lithospheric mantle close to oceanic-continent transition must thin more slowly than the overlying crust. This form of depth dependency is not common. For example, the Brazil-Angolan conjugate margin could have formed by uniform lithospheric thinning provided thick layers of salt were deposited in a preexisting 400 m deep topographic depression. Depth-dependent thinning is not required to account for rapid subsidence of presalt strata.

  8. Deep-tow geophysical survey above large exhumed mantle domains of the eastern Southwest Indian ridge

    NASA Astrophysics Data System (ADS)

    Bronner, A.; Munschy, M.; Sauter, D.; Carlut, J.; Searle, R.; Cannat, M.

    2012-04-01

    The recent discovery of a new type of seafloor, the "smooth seafloor", formed with no or very little volcanic activity along the easternmost part of the ultra-slow spreading Southwest Indian ridge (SWIR) shows an unexpected complexity in processes of generation of the oceanic lithosphere. There, detachment faulting is thought to be a mechanism for efficient exhumation of deep-seated mantle rocks. We present here a deep-tow geological-geophysical survey over smooth seafloor at the eastern SWIR (62-64°N) combining multibeam bathymetric data, magnetic data, geology mapping from sidescan sonar (TOBI) images and results from dredge sampling. We introduce a new type of calibration approach for deep-tow fluxgate magnetometer. We show that magnetic data can be corrected from the magnetic effect of the vehicle with no recourse to its attitude (pitch, roll and heading) but only using the 3 components recorded by the magnetometer and an approximation of the scalar intensity of the Earth magnetic field. The collected dredge samples as well as the sidescan sonar images confirm the presence of large areas of exhumed mantle-derived peridodites surrounded by a few volcanic constructions. We investigate the possibility that magnetic anomalies are either caused by serpentinized peridotites and/or magmatic intrusions. We show that the magnetic signature of the smooth seafloor is clearly weaker than the surrounding volcanic areas. Moreover, the calculated magnetization of a source layer as well as the comparison between deep-tow and sea-surface magnetic data argue for strong East-West variability in the distribution of the magnetized sources. This variability may result from fluid-rock interactions along the detachment faults as well as from the occurrence of small sized and thin volcanic patches and thus questions the seafloor spreading origin of the corresponding magnetic anomalies. Finally, we provide magnetic arguments, as calculation of block rotation or spreading asymmetry in

  9. Short and long term evolution of deep giant submarine dunes in continental shelf environment: the example of the 'Banc du Four' (Western Brittany, France)

    NASA Astrophysics Data System (ADS)

    Franzetti, M.; Le Roy, P.; Garlan, T.; Delacourt, C.; Thibaud, R.; Cancouet, R.; Graindorge, D.; Prunier, C.; Sukhovich, A.; Deschamps, A.

    2013-12-01

    The deep sandwave dynamics is still in debate. Understanding the migration processes and the resulting evolution of their 3D internal architecture are scientifically challenging. To address these questions we realized two swath bathymetry surveys complemented with seismic reflection across the large sandwaves field named 'Banc du Four'. It is located offshore the Western Brittany and is composed of more 500 dunes. Some of the dunes' wavelengths and heights exceed 1000m and 30m respectively placing them among the largest dunes ever described. Equilibrium laws obtained from our morphological analysis are not completely in agreement with those described in previous studies of similar structures in shallow waters. Relatively high migration velocities on deep continental shelves (from 3 to 20m.yr-1) attest of their still present dynamical equilibrium. Internal-external morphological and kinematical analyses show the existence of two different dynamic regimes. Interpretation of the seismic reflection data allowed reconstructing long-term evolution of the sandbank and the establishment of progressive connections between stepped submarine channels and tidal dynamics during the last sea-level rise.

  10. DUAL SUPERMASSIVE BLACK HOLE CANDIDATES IN THE AGN AND GALAXY EVOLUTION SURVEY

    SciTech Connect

    Comerford, Julia M.; Schluns, Kyle; Greene, Jenny E.; Cool, Richard J.

    2013-11-01

    Dual supermassive black holes (SMBHs) with kiloparsec-scale separations in merger-remnant galaxies are informative tracers of galaxy evolution, but the avenue for identifying them in large numbers for such studies is not yet clear. One promising approach is to target spectroscopic signatures of systems where both SMBHs are fueled as dual active galactic nuclei (AGNs), or where one SMBH is fueled as an offset AGN. Dual AGNs may produce double-peaked narrow AGN emission lines, while offset AGNs may produce single-peaked narrow AGN emission lines with line-of-sight velocity offsets relative to the host galaxy. We search for such dual and offset systems among 173 Type 2 AGNs at z < 0.37 in the AGN and Galaxy Evolution Survey (AGES), and we find two double-peaked AGNs and five offset AGN candidates. When we compare these results to a similar search of the DEEP2 Galaxy Redshift Survey and match the two samples in color, absolute magnitude, and minimum velocity offset, we find that the fraction of AGNs that are dual SMBH candidates increases from z = 0.25 to z = 0.7 by a factor of ∼6 (from 2/70 to 16/91, or 2.9{sup +3.6}{sub -1.9}% to 18{sup +5}{sub -5}%). This may be associated with the rise in the galaxy merger fraction over the same cosmic time. As further evidence for a link with galaxy mergers, the AGES offset and dual AGN candidates are tentatively ∼3 times more likely than the overall AGN population to reside in a host galaxy that has a companion galaxy (from 16/173 to 2/7, or 9{sup +3}{sub -2}% to 29{sub -19}{sup +26}%). Follow-up observations of the seven offset and dual AGN candidates in AGES will definitively distinguish velocity offsets produced by dual SMBHs from those produced by narrow-line region kinematics, and will help sharpen our observational approach to detecting dual SMBHs.

  11. SXDF-ALMA 2-arcmin2 deep survey: 1.1-mm number counts

    NASA Astrophysics Data System (ADS)

    Hatsukade, Bunyo; Kohno, Kotaro; Umehata, Hideki; Aretxaga, Itziar; Caputi, Karina I.; Dunlop, James S.; Ikarashi, Soh; Iono, Daisuke; Ivison, Rob J.; Lee, Minju; Makiya, Ryu; Matsuda, Yuichi; Motohara, Kentaro; Nakanishi, Kouichiro; Ohta, Kouji; Tadaki, Ken-ich; Tamura, Yoichi; Wang, Wei-Hao; Wilson, Grant W.; Yamaguchi, Yuki; Yun, Min S.

    2016-06-01

    We report 1.1-mm number counts revealed with the Atacama Large Millimeter/submillimeter Array (ALMA) in the Subaru/XMM-Newton Deep Survey Field (SXDF). The advent of ALMA enables us to reveal millimeter-wavelength number counts down to the faint end without source confusion. However, previous studies are based on the ensemble of serendipitously detected sources in fields originally targeting different sources and could be biased due to the clustering of sources around the targets. We derive number counts in the flux range of 0.2-2 mJy by using 23 (≥4σ) sources detected in a continuous 2.0-arcmin2 area of the SXDF. The number counts are consistent with previous results within errors, suggesting that the counts derived from serendipitously detected sources are not significantly biased, although there could be field-to-field variation due to the small survey area. By using the best-fitting function of the number counts, we find that ˜40% of the extragalactic background light at 1.1 mm is resolved at S1.1mm > 0.2 mJy.

  12. The Top 10 List of Gravitational Lens Candidates from the HUBBLE SPACE TELESCOPE Medium Deep Survey

    NASA Astrophysics Data System (ADS)

    Ratnatunga, Kavan U.; Griffiths, Richard E.; Ostrander, Eric J.

    1999-05-01

    A total of 10 good candidates for gravitational lensing have been discovered in the WFPC2 images from the Hubble Space Telescope (HST) Medium Deep Survey (MDS) and archival primary observations. These candidate lenses are unique HST discoveries, i.e., they are faint systems with subarcsecond separations between the lensing objects and the lensed source images. Most of them are difficult objects for ground-based spectroscopic confirmation or for measurement of the lens and source redshifts. Seven are ``strong lens'' candidates that appear to have multiple images of the source. Three are cases in which the single image of the source galaxy has been significantly distorted into an arc. The first two quadruply lensed candidates were reported by Ratnatunga et al. We report on the subsequent eight candidates and describe them with simple models based on the assumption of singular isothermal potentials. Residuals from the simple models for some of the candidates indicate that a more complex model for the potential will probably be required to explain the full structural detail of the observations once they are confirmed to be lenses. We also discuss the effective survey area that was searched for these candidate lens objects.

  13. COOL WHITE DWARFS FOUND IN THE UKIRT INFRARED DEEP SKY SURVEY

    SciTech Connect

    Leggett, S. K.; Nitta, A.; Lodieu, N.

    2011-07-01

    We present the results of a search for cool white dwarfs in the United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). The UKIDSS LAS photometry was paired with the Sloan Digital Sky Survey to identify cool hydrogen-rich white dwarf candidates by their neutral optical colors and blue near-infrared colors, as well as faint reduced proper motion magnitudes. Optical spectroscopy was obtained at Gemini Observatory and showed the majority of the candidates to be newly identified cool degenerates, with a small number of G- to K-type (sub)dwarf contaminants. Our initial search of 280 deg{sup 2} of sky resulted in seven new white dwarfs with effective temperature T{sub eff} {approx} 6000 K. The current follow-up of 1400 deg{sup 2} of sky has produced 13 new white dwarfs. Model fits to the photometry show that seven of the newly identified white dwarfs have 4120 K {<=}T{sub eff} {<=} 4480 K, and cooling ages between 7.3 Gyr and 8.7 Gyr; they have 40 km s{sup -1} {<=} v{sub tan} {<=} 85 km s{sup -1} and are likely to be thick disk 10-11 Gyr-old objects. The other half of the sample has 4610 K {<=}T{sub eff} {<=} 5260 K, cooling ages between 4.3 Gyr and 6.9 Gyr, and 60 km s{sup -1} {<=} v{sub tan} {<=} 100 km s{sup -1}. These are either thin disk remnants with unusually high velocities, or lower-mass remnants of thick disk or halo late-F or G stars.

  14. The evolution of volcano-hosted geothermal systems based on deep wells from Karaha-Telaga Bodas, Indonesia

    USGS Publications Warehouse

    Moore, J.N.; Allis, R.G.; Nemcok, M.; Powell, T.S.; Bruton, C.J.; Wannamaker, P.E.; Raharjo, I.B.; Norman, D.I.

    2008-01-01

    Temperature and pressure surveys, fluid samples, and petrologic analyses of rock samples from deep drill holes at the Karaha - Telaga Bodas geothermal field on the volcanic ridge extending northward from Galunggung Volcano, West Java, have provided a unique opportunity to characterize the evolution of an active volcano-hosted geothermal system. Wells up to 3 km in depth have encountered temperatures as high as 353??C and a weakly altered granodiorite that intruded to within 2 to 3 km of the surface. The intrusion is shallowest beneath the southern end of the field where an acid lake overlies a nearly vertical low resistivity structure (<10 ohm-m) defined by magnetotelluric measurements. This structure is interpreted to represent a vapor-dominated chimney that provides a pathway to the surface for magmatic gases. Four distinct hydrothermal mineral assemblages document the evolution of the geothermal system and the transition from liquid- to vapor-dominated conditions. The earliest assemblage represents the initial liquid-dominated system generated during emplacement of the granodiorite between 5910 ?? 76 and 4200 ?? 150 y BP. Tourmaline, biotite, actinolite, epidote and clay minerals were deposited contemporaneously at progressively greater distances from the intrusive contact (assemblage 1). At 4200 ?? 150 y BP, flank collapse and the formation of the volcano's crater, Kawah Galunggung, resulted in catastrophic decompression and boiling of the hydrothermal fluids. This event initiated development of the modern vapor-dominated regime. Chalcedony and then quartz were deposited as the early low salinity liquids boiled (assemblage 2). Both vapor- and liquid-rich fluid inclusions were trapped in the quartz crystals. Liquid-rich fluid inclusions from the southern part of the field record salinities ranging from 0 to 26 weight percent NaCl- CaCl2 equivalent and locally contain fluorite daughter crystals. We suggest, based on temperature-salinity relationships and evidence

  15. MOIRCS DEEP SURVEY. V. A UNIVERSAL RELATION FOR STELLAR MASS AND SURFACE BRIGHTNESS OF GALAXIES

    SciTech Connect

    Ichikawa, Takashi; Kajisawa, Masaru; Yamada, Toru; Akiyama, Masayuki; Yoshikawa, Tomohiro; Onodera, Masato

    2010-02-01

    We present a universal linear correlation between the stellar mass and surface brightness (SB) of galaxies at 0.3 < z < 3, using a deep K-band-selected catalog in the GOODS-North region. The correlation has a nearly constant slope, independent of redshift and color of galaxies in the rest-z frame. Considering unresolved compact galaxies, the tight correlation gives a lower boundary of SB for a given stellar mass; lower SB galaxies are prohibited over the boundary. The universal slope suggests that the stellar mass in galaxies was built up over their cosmic histories in a similar manner irrelevant to galaxy mass, as opposed to the scenario that massive galaxies mainly accumulated their stellar mass by major merging. In contrast, SB shows a strong dependence on redshift for a given stellar mass. It evolves as approx(1 + z){sup -2.0a}pprox{sup -0.8}, in addition to dimming as (1 + z){sup 4} by the cosmological expansion effect. The brightening depends on galaxy color and stellar mass. The blue population (rest-frame U - V < 0), which is dominated by young and star-forming galaxies, evolves as approx(1 + z){sup -0.8+}-{sup 0.3} in the rest-V band. On the other hand, the red population (U - V>0) and the massive galaxies (M{sub *}>10{sup 10} M{sub sun}) show stronger brightening, (1 + z){sup -1.5+}-{sup 0.1}. By comparison with galaxy evolution models, the phenomena are well understood by the pure luminosity evolution of galaxies out to z approx 3.

  16. IDENTIFYING LUMINOUS ACTIVE GALACTIC NUCLEI IN DEEP SURVEYS: REVISED IRAC SELECTION CRITERIA

    SciTech Connect

    Donley, J. L.; Koekemoer, A. M.; Brusa, M.; Salvato, M.; Capak, P.; Cardamone, C. N.; Civano, F.; Ilbert, O.; Impey, C. D.; Kartaltepe, J. S.; Miyaji, T.; Sanders, D. B.; Trump, J. R.

    2012-04-01

    Spitzer/IRAC selection is a powerful tool for identifying luminous active galactic nuclei (AGNs). For deep IRAC data, however, the AGN selection wedges currently in use are heavily contaminated by star-forming galaxies, especially at high redshift. Using the large samples of luminous AGNs and high-redshift star-forming galaxies in COSMOS, we redefine the AGN selection criteria for use in deep IRAC surveys. The new IRAC criteria are designed to be both highly complete and reliable, and incorporate the best aspects of the current AGN selection wedges and of infrared power-law selection while excluding high-redshift star-forming galaxies selected via the BzK, distant red galaxy, Lyman-break galaxy, and submillimeter galaxy criteria. At QSO luminosities of log L{sub 2-10keV}(erg s{sup -1}) {>=}44, the new IRAC criteria recover 75% of the hard X-ray and IRAC-detected XMM-COSMOS sample, yet only 38% of the IRAC AGN candidates have X-ray counterparts, a fraction that rises to 52% in regions with Chandra exposures of 50-160 ks. X-ray stacking of the individually X-ray non-detected AGN candidates leads to a hard X-ray signal indicative of heavily obscured to mildly Compton-thick obscuration (log N{sub H} (cm{sup -2}) = 23.5 {+-} 0.4). While IRAC selection recovers a substantial fraction of luminous unobscured and obscured AGNs, it is incomplete to low-luminosity and host-dominated AGNs.

  17. Deep Photometry of Galaxies in the VEGAS Survey: The Case of NGC 4472

    NASA Astrophysics Data System (ADS)

    Spavone, M.

    The VST-VEGAS project is aimed at observing and studying a rich sample of nearby early-type galaxies in order to systematically characterize their properties over a wide baseline of sizes and out to the faint outskirts where data are rather scarce so far. The external regions of galaxies more easily retain signatures about the formation and evolution mechanisms which shaped them, as their relaxation time are longer, and they are more weakly influenced by processes such as mergers, secular evolution, central black hole activity, and supernova feedback on the ISM, which tend to level age and metallicity gradients. The collection of a wide photometric dataset of a large number of galaxies in various environmental conditions, may help to shed light on these questions. To this end VEGAS exploits the potential of the VLT Survey Telescope (VST) which provides high quality images of 1 deg2 field of view in order to satisfy both the requirement of high resolution data and the need of studying nearby, and thus large, objects. We present a detailed study of the surface photometry of the elliptical galaxy NGC4472 and of smaller ETGs in its field, performed by using new g and i bands images to constrain the formation history of this nearby giant galaxy, and to investigate the presence of very faint substructures in its surroundings.

  18. The Great Observatories Origins Deep Survey. VLT/VIMOS spectroscopy in the GOODS-south field: Part II

    NASA Astrophysics Data System (ADS)

    Balestra, I.; Mainieri, V.; Popesso, P.; Dickinson, M.; Nonino, M.; Rosati, P.; Teimoorinia, H.; Vanzella, E.; Cristiani, S.; Cesarsky, C.; Fosbury, R. A. E.; Kuntschner, H.; Rettura, A.

    2010-03-01

    (EW) of the Ly-α and found evidence for a lack of bright LBGs with high EW of the Ly-α. Finally, we obtained new redshifts for 12 X-ray sources of the CDFS and extended-CDFS. Conclusions: After the completion of the two complementary ESO/GOODS spectroscopic campaigns with VIMOS and FORS2 at VLT, the number of spectroscopic redshifts in CDFS/GOODS field increased dramatically, in particular at z ⪆ 2. These data provide the redshift information indispensable to achieve the scientific goals of GOODS, such as tracing the evolution of galaxy masses, morphologies, clustering, and star formation. Based on observations made at the European Southern Observatory, Paranal, Chile (ESO program 171.A-3045 The Great Observatories Origins Deep Survey: ESO Public Observations of the SIRTF Legacy/HST Treasury/Chandra Deep Field South.)Catalogs and data products are available in electronic form at http://archive.eso.org/cms/eso-data/data-packagesAppendices are only available in electronic form at http://www.aanda.org

  19. The DEEP2 Galaxy Redshift Survey: Clustering of Galaxies in Early Data

    NASA Astrophysics Data System (ADS)

    Coil, Alison L.; Davis, Marc; Madgwick, Darren S.; Newman, Jeffrey A.; Conselice, Christopher J.; Cooper, Michael; Ellis, Richard S.; Faber, S. M.; Finkbeiner, Douglas P.; Guhathakurta, Puragra; Kaiser, Nick; Koo, David C.; Phillips, Andrew C.; Steidel, Charles C.; Weiner, Benjamin J.; Willmer, Christopher N. A.; Yan, Renbin

    2004-07-01

    We measure the two-point correlation function ξ(rp,π) in a sample of 2219 galaxies between z=0.7 and 1.35 to a magnitude limit of RAB=24.1 from the first season of the DEEP2 Galaxy Redshift Survey. From ξ(rp,π) we recover the real-space correlation function, ξ(r), which we find can be approximated within the errors by a power law, ξ(r)=(r/r0)-γ, on scales ~0.1-10 h-1 Mpc. In a sample with an effective redshift of zeff=0.82, for a ΛCDM cosmology we find r0=3.53+/-0.81 h-1 Mpc (comoving) and γ=1.66+/-0.12, while in a higher redshift sample with zeff=1.14 we find r0=3.12+/-0.72 h-1 Mpc and γ=1.66+/-0.12. These errors are estimated from mock galaxy catalogs and are dominated by the cosmic variance present in the current data sample. We find that red, absorption-dominated, passively evolving galaxies have a larger clustering scale length, r0, than blue, emission-line, actively star-forming galaxies. Intrinsically brighter galaxies also cluster more strongly than fainter galaxies at z~=1. Our results imply that the DEEP2 galaxies have an effective bias b=0.96+/-0.13 if σ8DM=1 today or b=1.19+/-0.16 if σ8DM=0.8 today. This bias is lower than that predicted by semianalytic simulations at z~=1, which may be the result of our R-band target selection. We discuss possible evolutionary effects within our survey volume, and we compare our results with galaxy-clustering studies at other redshifts, noting that our star-forming sample at z~=1 has selection criteria very similar to the Lyman break galaxies at z~=3 and that our red, absorption-line sample displays a clustering strength comparable to the expected clustering of the Lyman break galaxy descendants at z~=1. Our results demonstrate that galaxy-clustering properties as a function of color, spectral type, and luminosity seen in the local universe were largely in place by z~=1.

  20. The Swift serendipitous survey in deep XRT GRB fields (SwiftFT). I. The X-ray catalog and number counts

    NASA Astrophysics Data System (ADS)

    Puccetti, S.; Capalbi, M.; Giommi, P.; Perri, M.; Stratta, G.; Angelini, L.; Burrows, D. N.; Campana, S.; Chincarini, G.; Cusumano, G.; Gehrels, N.; Moretti, A.; Nousek, J.; Osborne, J. P.; Tagliaferri, G.

    2011-04-01

    Aims: An accurate census of the active galactic nuclei (AGN) is a key step in investigating the nature of the correlation between the growth and evolution of super massive black holes and galaxy evolution. X-ray surveys provide one of the most efficient ways of selecting AGN. Methods: We searched for X-ray serendipitous sources in over 370 Swift-XRT fields centered on gamma ray bursts detected between 2004 and 2008 and observed with total exposures ranging from 10 ks to over 1 Ms. This defines the Swift Serendipitous Survey in deep XRT GRB fields, which is quite broad compared to existing surveys (~33 square degrees) and medium depth, with a faintest flux limit of 7.2 × 10-16 erg cm-2 s-1 in the 0.5 to 2 keV energy range (4.8 × 10-15 erg cm-2 s-1 at 50% completeness). The survey has a high degree of uniformity thanks to the stable point spread function and small vignetting correction factors of the XRT, moreover is completely random on the sky as GRBs explode in totally unrelated parts of the sky. Results: In this paper we present the sample and the X-ray number counts of the high Galactic-latitude sample, estimated with high statistics over a wide flux range (i.e., 7.2 × 10-16 ÷ ~ 5 × 10-13 erg cm-2 s-1 in the 0.5-2 keV band and 3.4 × 10-15 ÷ ~ 6 × 10-13 erg cm-2 s-1 in the 2-10 keV band). We detect 9387 point-like sources with a detection Poisson probability threshold of ≤ 2 × 10-5, in at least one of the three energy bands considered (i.e. 0.3-3 keV, 2-10 keV, and 0.3-10 keV), for the total sample, while 7071 point-like sources are found at high Galactic-latitudes (i.e. |b| ≥ 20 deg). The large number of detected sources resulting from the combination of large area and deep flux limits make this survey a new important tool for investigating the evolution of AGN. In particular, the large area permits finding rare high-luminosity objects like QSO2, which are poorly sampled by other surveys, adding precious information for the luminosity function

  1. A Wide-Field Survey in the Chandra Deep Field-South Region: A Combined GTO + GO Approach

    NASA Astrophysics Data System (ADS)

    Garmire, Gordon

    2013-09-01

    We propose to perform a wide-field (2.2 square degree) survey around the Chandra Deep Field-South (CDF-S) and Extended Chandra Deep Field-South (E-CDF-S). This survey will complement the large observational investments made in multi-square-degree surveys in the CDF-S region by Spitzer, Herschel, the Australia Telescope Compact Array, PRIMUS, Pan-STARRS, DES, LSST, and other facilities. It will allow us to identify the most-luminous active galaxies to z = 1.5-2 and to investigate large-scale structures in the CDF-S region. This is the GTO component of a GTO + GO project; the associated GO observations will be proposed as a Cycle 15 Large Project.

  2. deepBase v2.0: identification, expression, evolution and function of small RNAs, LncRNAs and circular RNAs from deep-sequencing data

    PubMed Central

    Zheng, Ling-Ling; Li, Jun-Hao; Wu, Jie; Sun, Wen-Ju; Liu, Shun; Wang, Ze-Lin; Zhou, Hui; Yang, Jian-Hua; Qu, Liang-Hu

    2016-01-01

    Small non-coding RNAs (e.g. miRNAs) and long non-coding RNAs (e.g. lincRNAs and circRNAs) are emerging as key regulators of various cellular processes. However, only a very small fraction of these enigmatic RNAs have been well functionally characterized. In this study, we describe deepBase v2.0 (http://biocenter.sysu.edu.cn/deepBase/), an updated platform, to decode evolution, expression patterns and functions of diverse ncRNAs across 19 species. deepBase v2.0 has been updated to provide the most comprehensive collection of ncRNA-derived small RNAs generated from 588 sRNA-Seq datasets. Moreover, we developed a pipeline named lncSeeker to identify 176 680 high-confidence lncRNAs from 14 species. Temporal and spatial expression patterns of various ncRNAs were profiled. We identified approximately 24 280 primate-specific, 5193 rodent-specific lncRNAs, and 55 highly conserved lncRNA orthologs between human and zebrafish. We annotated 14 867 human circRNAs, 1260 of which are orthologous to mouse circRNAs. By combining expression profiles and functional genomic annotations, we developed lncFunction web-server to predict the function of lncRNAs based on protein-lncRNA co-expression networks. This study is expected to provide considerable resources to facilitate future experimental studies and to uncover ncRNA functions. PMID:26590255

  3. deepBase v2.0: identification, expression, evolution and function of small RNAs, LncRNAs and circular RNAs from deep-sequencing data.

    PubMed

    Zheng, Ling-Ling; Li, Jun-Hao; Wu, Jie; Sun, Wen-Ju; Liu, Shun; Wang, Ze-Lin; Zhou, Hui; Yang, Jian-Hua; Qu, Liang-Hu

    2016-01-01

    Small non-coding RNAs (e.g. miRNAs) and long non-coding RNAs (e.g. lincRNAs and circRNAs) are emerging as key regulators of various cellular processes. However, only a very small fraction of these enigmatic RNAs have been well functionally characterized. In this study, we describe deepBase v2.0 (http://biocenter.sysu.edu.cn/deepBase/), an updated platform, to decode evolution, expression patterns and functions of diverse ncRNAs across 19 species. deepBase v2.0 has been updated to provide the most comprehensive collection of ncRNA-derived small RNAs generated from 588 sRNA-Seq datasets. Moreover, we developed a pipeline named lncSeeker to identify 176 680 high-confidence lncRNAs from 14 species. Temporal and spatial expression patterns of various ncRNAs were profiled. We identified approximately 24 280 primate-specific, 5193 rodent-specific lncRNAs, and 55 highly conserved lncRNA orthologs between human and zebrafish. We annotated 14 867 human circRNAs, 1260 of which are orthologous to mouse circRNAs. By combining expression profiles and functional genomic annotations, we developed lncFunction web-server to predict the function of lncRNAs based on protein-lncRNA co-expression networks. This study is expected to provide considerable resources to facilitate future experimental studies and to uncover ncRNA functions. PMID:26590255

  4. Near-Infrared Galaxy Counts and Evolution from the Wide-Field ALHAMBRA Survey

    NASA Astrophysics Data System (ADS)

    Cristóbal-Hornillos, D.; Aguerri, J. A. L.; Moles, M.; Perea, J.; Castander, F. J.; Broadhurst, T.; Alfaro, E. J.; Benítez, N.; Cabrera-Caño, J.; Cepa, J.; Cerviño, M.; Fernández-Soto, A.; González Delgado, R. M.; Husillos, C.; Infante, L.; Márquez, I.; Martínez, V. J.; Masegosa, J.; del Olmo, A.; Prada, F.; Quintana, J. M.; Sánchez, S. F.

    2009-05-01

    The ALHAMBRA survey aims to cover 4 deg2 using a system of 20 contiguous, equal width, medium-band filters spanning the range 3500 Å-9700 Å plus the standard JHKs filters. Here we analyze deep near-IR number counts of one of our fields (ALH08) for which we have a relatively large area (0.5 deg2) and faint photometry (J = 22.4, H = 21.3, and K = 20.0 at the 50% of recovery efficiency for point-like sources). We find that the logarithmic gradient of the galaxy counts undergoes a distinct change to a flatter slope in each band: from 0.44 at [17.0, 18.5] to 0.34 at [19.5, 22.0] for the J band; for the H band 0.46 at [15.5, 18.0] to 0.36 at [19.0, 21.0], and in Ks the change is from 0.53 in the range [15.0, 17.0] to 0.33 in the interval [18.0, 20.0]. These observations together with faint optical counts are used to constrain models that include density and luminosity evolution of the local type-dependent luminosity functions. Our models imply a decline in the space density of evolved early-type galaxies with increasing redshift, such that only 30%-50% of the bulk of the present day red ellipticals was already in place at z ~ 1. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC).

  5. On the formation and evolution of plasmoids: A survey of ISEE 3 geotail data

    SciTech Connect

    Moldwin, M.B.; Hughes, W.J. )

    1992-12-01

    ISEE 3 magnetometer and electron plasma measurements from the 1983 Geotail Mission were surveyed to determine the magnetic and plasma properties of plasmoids and their evolution with distance downtail. Events were selected on the basis of a bipolar magnetic signature in either the geocentric solar magnetospheric B[sub z] and/or B[sub y] component; most had B[sub z] bipolar signatures. The authors found 366 events consistent with this signature while ISEE 3 was in the plasma sheet. Plasmoid length was determined using both the magnetometer and the electron plasma velocity data. They found the average length of plasmoids is 16.7 [plus minus] 13.0 R[sub E], significantly smaller than previous estimates. Many plasmoids have a well-defined magnetic core field, characterized by a field strength maximum at the center of the pass through the structure. The size, velocity, magnetic core strength, and B[sub z] field amplitude of plasmoids do not depend on distance beyond 100 R[sub E] downtail. The average electron temperature inside plasmoids drops by a factor of 2 and the electron density increases by a factor of 2 as plasmoids propagate from near Earth distances (within 100 R[sub E] of the Earth) to the deep tail. They conclude that the stable size of the plasmoids, the density increase and the temperature decrease are consistent with a flux of cold electrons into the plasmoid. The strong correlation of interplanetary magnetic field B[sub y] an hour before the event with the strength and direction of B[sub y] observed inside plasmoids, the existence of events with the bipolar signature in both the B[sub y] and B[sub z] components, and the possible mass flux all are consistent with plasmoids being open' magnetic structures.

  6. A Systematic Survey of Protoclusters at z ~ 3–6 in the CFHTLS Deep Fields

    NASA Astrophysics Data System (ADS)

    Toshikawa, Jun; Kashikawa, Nobunari; Overzier, Roderik; Malkan, Matthew A.; Furusawa, Hisanori; Ishikawa, Shogo; Onoue, Masafusa; Ota, Kazuaki; Tanaka, Masayuki; Niino, Yuu; Uchiyama, Hisakazu

    2016-08-01

    We present the discovery of three protoclusters at z ˜ 3–4 with spectroscopic confirmation in the Canada–France–Hawaii Telescope Legacy Survey Deep Fields. In these fields, we investigate the large-scale projected sky distribution of z ˜ 3–6 Lyman-break galaxies and identify 21 protocluster candidates from regions that are overdense at more than 4σ overdensity significance. Based on cosmological simulations, it is expected that more than 76% of these candidates will evolve into a galaxy cluster of at least a halo mass of 1014 M ⊙ at z = 0. We perform follow-up spectroscopy for eight of the candidates using Subaru/FOCAS, Keck II/DEIMOS, and Gemini-N/GMOS. In total we target 462 dropout candidates and obtain 138 spectroscopic redshifts. We confirm three real protoclusters at z = 3–4 with more than five members spectroscopically identified and find one to be an incidental overdense region by mere chance alignment. The other four candidate regions at z ˜ 5–6 require more spectroscopic follow-up in order to be conclusive. A z = 3.67 protocluster, which has 11 spectroscopically confirmed members, shows a remarkable core-like structure composed of a central small region (<0.5 physical Mpc) and an outskirts region (˜1.0 physical Mpc). The Lyα equivalent widths of members of the protocluster are significantly smaller than those of field galaxies at the same redshift, while there is no difference in the UV luminosity distributions. These results imply that some environmental effects start operating as early as at z ˜ 4 along with the growth of the protocluster structure. This study provides an important benchmark for our analysis of protoclusters in the upcoming Subaru/HSC imaging survey and its spectroscopic follow-up with the Subaru/PFS that will detect thousands of protoclusters up to z ˜ 6.

  7. Initial Optical Counterpart Identifications for Chandra Deep Survey X-ray Sources towards the Galactic Center

    NASA Astrophysics Data System (ADS)

    Zhao, P.; Grindlay, J. E.; Hong, J.; Laycock, S.; Baganoff, F. K.; Muno, M. P.; Garmire, G. P.; Morris, M.

    2003-03-01

    We present the initial optical counterpart identifications for the Chandra Catalog of X-ray sources towards the Galactic Center (Muno et al. ApJ submitted). 2357 X-ray point sources are detected during 590 ks of Chandra ACIS-I observations with a 17'x17' field around SgrA*. The search for their optical counterparts is conducted with moderately deep V, R, I and Hα images covering the same field taken with the Mosaic camera on the CTIO 4-m telescope in March 2000 as part of the Chandra Multiwavelength Plane (ChaMPlane) Survey. The error radius of each Chandra source is estimated with a raytrace/wavdetect simulation based on the source off-axis angle and net counts. Some 237 sources are detected below 1.2 keV and with >99% source significance in the full 17' field. They are likely sources in the foreground of the Galactic Center. 204 of the 237 sources have matching optical counterparts. For the ˜2000 sources detected in the hard band (2.5--8 keV), only ˜10% have optical matching (at R<23). And most of these ˜10% matches are likely coincident matches with foreground stars. We present our optical counterpart identification method used for the ChaMPlane Survey and the V, R, I, Hα magnitudes of the optical counterparts of this initial sample. This work is supported by NASA/SAO grant AR1-2001X, AR2-3002A and NSF grant AST-0098683.

  8. Reconstructing the Dynamics of HIV Evolution within Hosts from Serial Deep Sequence Data

    PubMed Central

    Poon, Art F. Y.; Swenson, Luke C.; Bunnik, Evelien M.; Edo-Matas, Diana; Schuitemaker, Hanneke; van 't Wout, Angélique B.; Harrigan, P. Richard

    2012-01-01

    At the early stage of infection, human immunodeficiency virus (HIV)-1 predominantly uses the CCR5 coreceptor for host cell entry. The subsequent emergence of HIV variants that use the CXCR4 coreceptor in roughly half of all infections is associated with an accelerated decline of CD4+ T-cells and rate of progression to AIDS. The presence of a ‘fitness valley’ separating CCR5- and CXCR4-using genotypes is postulated to be a biological determinant of whether the HIV coreceptor switch occurs. Using phylogenetic methods to reconstruct the evolutionary dynamics of HIV within hosts enables us to discriminate between competing models of this process. We have developed a phylogenetic pipeline for the molecular clock analysis, ancestral reconstruction, and visualization of deep sequence data. These data were generated by next-generation sequencing of HIV RNA extracted from longitudinal serum samples (median 7 time points) from 8 untreated subjects with chronic HIV infections (Amsterdam Cohort Studies on HIV-1 infection and AIDS). We used the known dates of sampling to directly estimate rates of evolution and to map ancestral mutations to a reconstructed timeline in units of days. HIV coreceptor usage was predicted from reconstructed ancestral sequences using the geno2pheno algorithm. We determined that the first mutations contributing to CXCR4 use emerged about 16 (per subject range 4 to 30) months before the earliest predicted CXCR4-using ancestor, which preceded the first positive cell-based assay of CXCR4 usage by 10 (range 5 to 25) months. CXCR4 usage arose in multiple lineages within 5 of 8 subjects, and ancestral lineages following alternate mutational pathways before going extinct were common. We observed highly patient-specific distributions and time-scales of mutation accumulation, implying that the role of a fitness valley is contingent on the genotype of the transmitted variant. PMID:23133358

  9. Galaxy pairs in deep HST images: Evidence for evolution in the galaxy merger rate

    NASA Technical Reports Server (NTRS)

    Burkey, Jordan M.; Keel, William C.; Windhorst, Rogier A.; Franklin, Barbara E.

    1994-01-01

    We use four deep serendipitous fields observed with the Hubble Space Telescope (HST) Wide-Field Camera to constrain the rate of galaxy merging between the current epoch and z approximately equals 0.7. Since most mergers occur between members of bound pairs, the merger rate is given to a good approximation by (half) the rate of disappearance of galaxies in pairs. An objective criterion for pair membership shows that 34% +/- 9% of our HST galaxies with I = 18-22 belong to pairs, compared to 7% locally. This means that about 13% of the galaxy population has disappeared due to merging in the cosmic epoch corresponding to this magnitude interval (or 0.1 approximately less than z approximately less than 0.7). Our pair fraction is a lower limit: correction for pair members falling below our detection threshold might raise the fraction to approximately 50%. Since we address only two-galaxy merging, these values do not include physical systems of higher multiplicity. Incorporating I-band field-galaxy redshift distributions, the pair fraction grows with redshift as alpha(1 + z)(exp 3.5 +/- 0.5) and the merger rate as (1 + z)(exp 2.5 +/- 0.5). This may have significant implications for the interpretation of galaxy counts (disappearance of faint blue galaxies), the cosmological evolution of faint radio sources and quasars (which evolve approximately as (1 + z)(exp 3), the similarity in the power law is necessary but not sufficient evidence for a causal relation), statistics of QSO companions, the galaxy content in distant clusters, and the merging history of a 'typical' galaxy.

  10. DEEP NEAR-INFRARED SURVEY OF THE PIPE NEBULA. II. DATA, METHODS, AND DUST EXTINCTION MAPS

    SciTech Connect

    Roman-Zuniga, Carlos G.; Lada, Charles J.; Lombardi, Marco

    2010-12-20

    We present a new set of high-resolution dust extinction maps of the nearby and essentially starless Pipe Nebula molecular cloud. The maps were constructed from a concerted deep near-infrared imaging survey with the ESO-VLT, ESO-NTT, CAHA 3.5 m telescopes, and 2MASS data. The new maps have a resolution three times higher than the previous extinction map of this cloud by Lombardi et al. and are able to resolve structures down to 2600 AU. We detect 244 significant extinction peaks across the cloud. These peaks have masses between 0.1 and 18.4 M{sub sun}, diameters between 1.2 and 5.7 x 10{sup 4} AU (0.06 and 0.28 pc), and mean densities of about 10{sup 4} cm{sup -3}, all in good agreement with previous results. From the analysis of the mean surface density of companions we find a well-defined scale near 1.4 x 10{sup 4} AU below which we detect a significant decrease in structure of the cloud. This scale is smaller than the Jeans length calculated from the mean density of the peaks. The surface density of peaks is not uniform but instead it displays clustering. Extinction peaks in the Pipe Nebula appear to have a spatial distribution similar to the stars in Taurus, suggesting that the spatial distribution of stars evolves directly from the primordial spatial distribution of high-density material.

  11. X-ray Properties of Clusters from the Palomar Deep Survey

    NASA Astrophysics Data System (ADS)

    Holden, B. H.; Nichol, B. C.; Romer, A. K.; Ulmer, M. P.

    1996-05-01

    Twenty of the 79 z>0.2 distant, optically selected, cluster candidates in the Palomar Deep Cluster Survey (Postman et al. 1996) were serendipitously observed by the ROSAT satellite. We have reduced the three PSPC pointings that overlapped Postman et al. (1996) fields using the Snowden et al. (1994) Extended X-ray Analysis Software and a wavelet analysis source detection algorithm. We derive count rates for the cluster candidates inside a metric aperture defined by the estimate redshift quoted in Postman et al. (1996). We find all 20 clusters observed by the PSPC to be X-ray faint; only 4 were detected at >3sigma . The luminosities derived from the measured/upper-limit count rates are significantly lower than those predicted from the richness vs luminosity distribution derived for X-ray selected clusters (Edge & Stewart 1991). This discrepancy cannot be wholly attributed to projection effects; according to Postman et al. (1996) less than 30% of their objects are ``phantom clusters''. We will present evidence to support our conclusion that optically selected clusters are younger and less evolved than their X-ray selected counterparts.

  12. Measuring M Dwarf Rotation in the Pan-STARRS 1 Medium Deep Survey

    NASA Astrophysics Data System (ADS)

    Fong, Erin R.; Williams, Peter K. G.; Berger, Edo

    2016-01-01

    The rise of large-format CCDs and automated detection methods has greatly increased the tractability of large-scale studies of stellar rotation. Studies of the relationship between stellar rotation and magnetic activity show a strong correlation, supporting the concept of a rotationally-driven dynamo. However, the number of confirmed rotation periods for stars in the fully convective regime, whose magnetic dynamos are less well understood, remains low. Here we report on ongoing work to measure rotation periods for the M dwarf stellar population observed by the Pan-STARRS 1 Medium Deep Survey (PS1/MDS). We refine an initial sample of around 4.3 million sources using color cuts in each of the five Pan-STARRS 1 filters. Of these sources, we estimate there to be around 135,000 sources which are candidate M dwarfs with a spectral type of M1 or higher. We discuss the outcomes of various rotation period detection methods and present preliminary results. This work is supported in part by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant no. 1262851 and by the Smithsonian Institution.

  13. Survey of some recent stellar-evolution calculations

    NASA Technical Reports Server (NTRS)

    Sweigart, A. V.

    1978-01-01

    The stellar-evolution program developed by Sweigart (1973) was used to compute main sequence turnoff, red giant sequences, and horizontal branch sequences for many values of helium abundance and heavy-element abundance. The immediate aim has been to produce a self-consistent set of evolutionary sequences for wide ranges in the composition and mass. The long-term aim involves application to cluster HR diagrams and the integrated properties of galaxies. Turnoff sequences, red giant sequences, and horizontal branch sequences are discussed.

  14. A DEEP HUBBLE SPACE TELESCOPE H-BAND IMAGING SURVEY OF MASSIVE GAS-RICH MERGERS. II. THE QUEST QSOs

    SciTech Connect

    Veilleux, S.; Kim, D.-C.; Rupke, D. S. N. E-mail: ddk3wc@mail.astro.virginia.edu

    2009-08-10

    We report the results from a deep Hubble Space Telescope (HST) NICMOS H-band imaging survey of 28 z < 0.3 QSOs from the Palomar-Green (PG) sample. This program is part of QUEST (Quasar/ULIRG Evolution Study) and complements a similar set of data on 26 highly nucleated ULIRGs presented in Paper I. Our analysis indicates that the fraction of QSOs with elliptical hosts is higher among QSOs with undetected far-infrared (FIR) emission, small infrared excess (L {sub IR}/L {sub B} < 10), and luminous hosts. The hosts of FIR-faint QSOs show a tendency to have less pronounced merger-induced morphological anomalies and larger QSO-to-host luminosity ratios on average than the hosts of FIR-bright QSOs, consistent with late-merger evolution from FIR-bright to FIR-faint QSOs. The spheroid sizes ({approx} 0.3-5.5 kpc) and total host luminosities ({approx} 0.6-7.2 L* {sub H}) of the radio-quiet PG QSOs in our sample are statistically indistinguishable from the ULIRG hosts presented in Paper I, while those of radio-loud PG QSOs are systematically larger and more luminous. ULIRGs and PG QSOs with elliptical hosts fall near, but not exactly on, the fundamental plane of inactive spheroids. We confirm the systematic trend noted in Paper I for objects with small ({approx}< 2 kpc) spheroids to be up to {approx} 1 mag brighter than inactive spheroids. The host colors and wavelength dependence of their sizes support the idea that these deviations are at least in part due to non-nuclear star formation. However, the amplitudes of these deviations depend mainly on host sizes, and possibly on infrared excess, but not on merger phase, QSO-to-host luminosity ratio, optical spectral type, active galactic nucleus fractional contribution to the bolometric luminosity, or host R - H color. Taken at face value (i.e., no correction for extinction or the presence of a young stellar population), the H-band spheroid-host luminosities imply black hole masses {approx} (5-200) x 10{sup 7} M {sub sun} and sub

  15. Evolution of deep centers in GaN grown by hydride vapor phaseepitaxy

    SciTech Connect

    Fang, Z.-Q.; Look, D.C.; Jasinski, J.; Benamara, M.; Liliental-Weber, Z.; Molnar, R.J.

    2001-04-18

    Deep centers and dislocation densities in undoped n GaN, grown by hydride vapor phase epitaxy (HVPE), were characterized as a function of the layer thickness by deep level transient spectroscopy and transmission electron microscopy, respectively. As the layer thickness decreases, the variety and concentration of deep centers increase, in conjunction with the increase of dislocation density. Based on comparison with electron irradiation induced centers, some dominant centers in HVPE GaN are identified as possible point defects.

  16. The Hubble Space Telescope Medium Deep Survey with the Wide Field and Planetary Camera. 1: Methodology and results on the field near 3C 273

    NASA Technical Reports Server (NTRS)

    Griffiths, R. E.; Ratnatunga, K. U.; Neuschaefer, L. W.; Casertano, S.; Im, M.; Wyckoff, E. W.; Ellis, R. S.; Gilmore, G. F.; Elson, R. A. W.; Glazebrook, K.

    1994-01-01

    We present results from the Medium Deep Survey (MDS), a Key Project using the Hubble Space Telescope (HST). Wide Field Camera (WFC) images of random fields have been taken in 'parallel mode' with an effective resolution of 0.2 sec full width at half maximum (FWHM) in the V(F555W) and I(F785LP) filters. The exposures presented here were targeted on a field away from 3C 273, and resulted in approximately 5 hr integration time in each filter. Detailed morphological structure is seen in galaxy images with total integrated magnitudes down to V approximately = 22.5 and I approximately = 21.5. Parameters are estimated that best fit the observed galaxy images, and 143 objects are identified (including 23 stars) in the field to a fainter limiting magnitude of I approximately = 23.5. We outline the extragalactic goals of the HST Medium Deep Survey, summarize our basic data reduction procedures, and present number (magnitude) counts, a color-magnitude diagram for the field, surface brightness profiles for the brighter galaxies, and best-fit half-light radii for the fainter galaxies as a function of apparent magnitude. A median galaxy half-light radius of 0.4 sec is measured, and the distribution of galaxy sizes versus magnitude is presented. We observe an apparent deficit of galaxies with half-light radii between approximately 0.6 sec and 1.5 sec, with respect to standard no-evolution or mild evolution cosmological models. An apparent excess of compact objects (half-light radii approximately 0.1 sec) is also observed with respect to those models. Finally, we find a small excess in the number of faint galaxy pairs and groups with respect to a random low-redshift field sample.

  17. Consistent nonlinear deterministic and stochastic evolution equations for deep to shallow water wave shoaling

    NASA Astrophysics Data System (ADS)

    Vrecica, Teodor; Toledo, Yaron

    2015-04-01

    oscillating terms, but as the water depth becomes shallow they change to an exponential growth (or decay) behavior. Hence, the formerly used localization technique cannot be justified for the shallow water region. A new formulation is devised for the localization in shallow water, it approximates the nonlinear non-local shoaling coefficient in shallow water and matches it to the one fitting to the intermediate water region. This allows the model behavior to be consistent from deep water to intermediate depths and up to the shallow water regime. Various simulations of the model were performed for the cases of intermediate, and shallow water, overall the model was found to give good results in both shallow and intermediate water depths. The essential difference between the shallow and intermediate nonlinear shoaling physics is explained via the dominating class III Bragg resonances phenomenon. By inspecting the resonance conditions and the nature of the dispersion relation, it is shown that unlike in the intermediate water regime, in shallow water depths the formation of resonant interactions is possible without taking into account bottom components. References Agnon, Y. & Sheremet, A. 1997 Stochastic nonlinear shoaling of directional spectra. J. Fluid Mech. 345, 79-99. Benney, D. J. & Saffman, P. G. 1966 Nonlinear interactions of random waves. Proc. R. Soc. Lond. A 289, 301-321. Bredmose, H., Agnon, Y., Madsen, P.A. & Schaffer, H.A. 2005 Wave transformation models with exact second-order transfer. European J. of Mech. - B/Fluids 24 (6), 659-682. Eldeberky, Y. & Madsen, P. A. 1999 Deterministic and stochastic evolution equations for fully dispersive and weakly nonlinear waves. Coastal Engineering 38, 1-24. Kaihatu, J. M. & Kirby, J. T. 1995 Nonlinear transformation of waves in infinite water depth. Phys. Fluids 8, 175-188. Holloway, G. 1980 Oceanic internal waves are not weak waves. J. Phys. Oceanogr. 10, 906-914. Stiassnie, M. & Drimer, N. 2006 Prediction of long forcing waves

  18. Numerical Simulation of Possible Evolution Scenarios of the Rosone Deep-Seated Gravitational Slope Deformation (Italian Alps, Piedmont)

    NASA Astrophysics Data System (ADS)

    Pirulli, Marina

    2016-06-01

    The large, deep-seated Rosone landslide (Western Italian Alps) has been known since the beginning of the twentieth century as an active phenomenon characterized by a slow but constant evolution. Its possible evolution, in terms of a catastrophic rock avalanche, could have serious consequences on several elements at risk, including a hydroelectric power plant. Runout estimates are needed to identify the potential impact on the territory of such an event and, when possible, to minimize hazard areas. This article analyses the evolution of three potential rock avalanche scenarios, with decreasing probability of occurrence and increasing impact on land planning. A comparison between runout results obtained by other authors and some new analyses that have been carried out with the three-dimensional continuum mechanics-based RASH3D code is made and commented on by highlighting the advantages, but also the limits, of using a more complete tool, such as RASH3D.

  19. Ocean Melting Greenland (OMG) bathymetric survey of northwest Greenland and implications for the recent evolution of its glaciers

    NASA Astrophysics Data System (ADS)

    Wood, M.; Rignot, E. J.; Willis, J. K.; Fenty, I. G.

    2015-12-01

    Oceans Melting Greenland (OMG) is a five-year Earth Ventures Suborbital Mission funded by NASA to investigate the role of the oceans in ice loss around the margins of the Greenland Ice Sheet, which includes measurements of seafloor bathymetry from multibeam surveys and airborne gravity, glacier surface elevation from high-frequency radar interferometry, and temperature/salinity/depth from vessels and airborne-dropped probes. Here, we describe the results of the 2016 bathymetry survey of northwest Greenland that took place in the summer of 2015: july 22-August 19 and Sept 2-Sept 16 spanning from Ilulissat to Thule AFB in north Greenland, and to be complemented by a survey of southeast Greenland in 2016. We deployed a multibeam Reson 7160 with 512 beams installed on the hull of the Cape Race vessel, with enhanced capabilities for fjord wall and ice face mapping. The survey tracks were optimized based on the IBCAO3 database, recent cruises, airborne gravity data collected by NASA Operation IceBridge which indicated the presence of troughs, bed topography mapped inland using a mass conservation approach, the spatial distribution of ice discharge to locate the largest outlets and maximizing the number of major fjords sampled during the survey, with the goal to identify all troughs that are major pathways for subsurface ocean heat, and constrain as many glacier ice front thickness as permitted by time and the practicality of navigating the ice-choked fjords. The data reveal many deep, U-shaped, submarine valleys connected to the glaciers, intercut with sills and over deepened in narrower passages where former glaciers and ice streams merged into larger units; as well as fjords ending in shallow plateaus with glaciers in retreated positions. The presence of warm, salty water of Atlantic origin (AW) in the fjords is documented using CTD. Some glaciers sit on shallow plateaus in cold, fresh polar waters (PW) at the end of deep fjords, while others are deeper and standing in

  20. The WARPS Survey - VIII. Evolution of the galaxy cluster X-ray Luminosity Function

    NASA Astrophysics Data System (ADS)

    Koens, L. A.; Maughan, B. J.; Jones, L. R.; Ebeling, H.; Horner, D. J.; Perlman, E. S.; Phillipps, S.; Scharf, C. A.

    2013-11-01

    We present measurements of the galaxy cluster X-ray Luminosity Function (XLF) from the Wide Angle ROSAT Pointed Survey (WARPS) and quantify its evolution. WARPS is a serendipitous survey of the central region of ROSAT pointed observations and was carried out in two phases (WARPS-I and WARPS-II). The results here are based on a final sample of 124 clusters, complete above a flux limit of 6.5 × 10-14 erg cm-2 s-1, with members out to redshift z ˜ 1.05, and a sky coverage of 70.9 deg2. We find significant evidence for negative evolution of the XLF, which complements the majority of X-ray cluster surveys. To quantify the suggested evolution, we perform a maximum likelihood analysis and conclude that the evolution is driven by a decreasing number density of high-luminosity clusters with redshift, while the bulk of the cluster population remains nearly unchanged out to redshift z ≈ 1.1, as expected in a low-density universe. The results are found to be insensitive to a variety of sources of systematic uncertainty that affect the measurement of the XLF and determination of the survey selection function. We perform a Bayesian analysis of the XLF to fully account for uncertainties in the local XLF on the measured evolution, and find that the detected evolution remains significant at the 95 per cent level. We observe a significant excess of clusters in the WARPS at 0.1 < z < 0.3 and LX ≈ 2 × 1043 erg s-1 compared with the reference low-redshift XLF, or our Bayesian fit to the WARPS data. We find that the excess cannot be explained by sample variance, or Eddington bias, and is unlikely to be due to problems with the survey selection function.

  1. From Romanticism to Deep Ecology: The Continuing Evolution in American Environmental Thought.

    ERIC Educational Resources Information Center

    Ackerson, David

    2000-01-01

    Describes the contributions to deep ecology of Henry Thoreau, who advocated acting upon strongly held convictions; John Muir, who adopted a biocentric view of nature; and Aldo Leopold, who formulated an egalitarian ecosystem ethic. While deep ecology is moving toward a new vision of humankind's relation to nature, it has yet to coalesce into a…

  2. A deep Spitzer survey of circumstellar disks in the young double cluster, h and χ Persei

    SciTech Connect

    Cloutier, Ryan; Currie, Thayne; Jayawardhana, Ray; Rieke, George H.; Kenyon, Scott J.; Balog, Zoltan E-mail: currie@astro.utoronto.ca E-mail: skenyon@cfa.harvard.edu

    2014-12-01

    We analyze very deep Infrared Array Camera and Multiband Imaging Photometer for Spitzer (MIPS) photometry of ∼12, 500 members of the 14 Myr old Double Cluster, h and χ Persei, building upon our earlier, shallower Spitzer Cycle 1 studies. Numerous likely members show infrared (IR) excesses at 8 μm and 24 μm, indicative of circumstellar dust. The frequency of stars with 8 μm excess is at least 2% for our entire sample, slightly lower (higher) for B/A stars (later type, lower mass stars). Optical spectroscopy also identifies gas in about 2% of systems, but with no clear trend between the presence of dust and gas. Spectral energy distribution modeling of 18 sources with detections at optical wavelengths through MIPS 24 μm reveals a diverse set of disk evolutionary states, including a high fraction of transitional disks, though similar data for all disk-bearing members would provide constraints. Using Monte Carlo simulations, we combine our results with those for other young clusters to study the global evolution of dust/gas disks. For nominal cluster ages, the e-folding times (τ{sub 0}) for the frequency of warm dust and gas are 2.75 Myr and 1.75 Myr, respectively. Assuming a revised set of ages for some clusters, these timescales increase to 5.75 and 3.75 Myr, respectively, implying a significantly longer typical protoplanetary disk lifetime than previously thought. In both cases, the transitional disk duration, averaged over multiple evolutionary pathways, is ≈1 Myr. Finally, 24 μm excess frequencies for 4-6 M {sub ☉} stars appear lower than for 1-2.5 M {sub ☉} stars in other 10-30 Myr old clusters.

  3. The Taiwan ECDFS Near-Infrared Survey: Ultra-deep J and KS Imaging in the Extended Chandra Deep Field-South

    NASA Astrophysics Data System (ADS)

    Hsieh, Bau-Ching; Wang, Wei-Hao; Hsieh, Chih-Chiang; Lin, Lihwai; Yan, Haojing; Lim, Jeremy; Ho, Paul T. P.

    2012-12-01

    We present ultra-deep J and KS imaging observations covering a 30' × 30' area of the Extended Chandra Deep Field-South (ECDFS) carried out by our Taiwan ECDFS Near-Infrared Survey (TENIS). The median 5σ limiting magnitudes for all detected objects in the ECDFS reach 24.5 and 23.9 mag (AB) for J and KS , respectively. In the inner 400 arcmin2 region where the sensitivity is more uniform, objects as faint as 25.6 and 25.0 mag are detected at 5σ. Thus, this is by far the deepest J and KS data sets available for the ECDFS. To combine TENIS with the Spitzer IRAC data for obtaining better spectral energy distributions of high-redshift objects, we developed a novel deconvolution technique (IRACLEAN) to accurately estimate the IRAC fluxes. IRACLEAN can minimize the effect of blending in the IRAC images caused by the large point-spread functions and reduce the confusion noise. We applied IRACLEAN to the images from the Spitzer IRAC/MUSYC Public Legacy in the ECDFS survey (SIMPLE) and generated a J+KS -selected multi-wavelength catalog including the photometry of both the TENIS near-infrared and the SIMPLE IRAC data. We publicly release the data products derived from this work, including the J and KS images and the J+KS -selected multi-wavelength catalog.

  4. Carbonate mound evolution and coral diagenesis viewed by U-series dating of deep water corals

    NASA Astrophysics Data System (ADS)

    Frank, N.; Ricard, E.; Blamart, D.; van der Land, C.; Colin, C.; Foubert, A.; van Rooij, D.; van Weering, T.

    2007-12-01

    U-series dating of constructional deep sea corals is a powerful tool to reconstruct the evolution of carbonate mound sediments driven by coral growth, sediment trapping and diagenesis. Here we have investigated in great detail the time framework of constructional corals such as L. pertusa and M. oculata on 5 different mounds of the eastern North Atlantic (on Rockall Bank and in Porcupine Seabight) taken at variable depth and location (610 to 880m water depth). Periods favorable for coral growth are the Holocene and prior interglacials such as marine isotope stage 5 and 7, while glacial coral growth seems inhibited or extremely reduced. Coral development is almost continuous throughout the Holocene since mound re-colonization about 10,500 years ago. Mound accumulation rates vary between 20 and 220 cm/kyr determined from the coral age - depth relationship in each core. Those changes are most likely driven by changes between horizontal and vertical mound accumulation, food supply and ocean circulation. In addition, coral dating allowed to identify an important erosional event recorded in core MD01-2455G from Rockall Bank. Here a 1m thick sediment layer containing ancient corals likely from the start of Holocene re-colonization was displaced (collapsed) from further upslope on top of younger corals of ~2500 to 3000 years age. Prior to the initiation of coral growth diagenesis occurred frequently resulting in (1) the construction of so called carbonate hardgrounds and/or (2) the dissolution of the pre-Holocene coral framework. Solely, the deepest selected core in Porcupine Seabight (MD01-2463G at 880m depth) reveals coral re-colonization on an undisturbed ancient reef structure that dates back to 250,000 years. Diagenesis of earlier coral reef generations leading to coral dissolution leads to a loss of magnetic susceptibility and open system behavior of the coral skeletons with respect to U-series dating. While the processes causing such diagenetic layers are barely

  5. Evolution of Continental Lower Crust Recorded By an Exhumed Deep Crustal Intracontinental Shear Zone

    NASA Astrophysics Data System (ADS)

    Dumond, G.; Mahan, K. H.; Regan, S. P.; Williams, M. L.; Goncalves, P.; Wood, V. R.

    2014-12-01

    Exposures of deep crustal shear zones are fundamental records of strain localization and the temporal evolution of ductile to brittle behavior as these tectonites were exhumed to the surface. We present results from a decade of field-based research on a deeply exhumed (~35 km-paleodepths) strike-slip shear zone in the western Churchill province of the Canadian Shield. The Grease River shear zone is a >400 km-long and 7 km-thick structure that cuts the Athabasca granulite terrane, North America's largest exposure of continental lower crust (>20,000 km2). The shear zone is dominated by granulite- to amphibolite-grade L-S and L>S tectonites characterized by penetrative NE-striking steeply-dipping foliations with gently-plunging to sub-horizontal stretching and intersection lineations. These fabrics are locally overprinted by pseudotachylyte and narrow (<500 m-thick) greenschist-grade zones of cataclasite. Dextral kinematics are defined by deflected foliation trajectories, C' shear bands, and well-developed σ- and δ-type porphyroclasts of Kfs + Pl + Opx + Grt + Hb in felsic to intermediate granulite paragneisses and orthogneisses. Data collected along a well-exposed, nearly 150 km-long segment of the shear zone documents a >100 m.y. episodic record of transpressive to strike-slip intracontinental strain accumulation that coincided with two oppositely convergent orogenies: the east-vergent arc-continent collision of the 1.94-1.90 Ga Taltson orogen and the west-vergent continent-continent collision of the 1.9-1.8 Ga Trans-Hudson orogen. Deformation mechanisms evolved from distributed ductile dynamic recrystallization and grain-size reduction to localized pseudotachylyte development, cataclastic flow, and brittle faulting. Lower crustal behavior during strain localization was dynamic. Melt-weakened mono-cyclic crust was juxtaposed against strong isobarically-cooled poly-cyclic crust along the shear zone at 1.92-1.90 Ga. Brittle-ductile reactivation of the structure

  6. Commercial bottom trawling: a driver of deep seascape evolution in the Anthropocene?

    NASA Astrophysics Data System (ADS)

    Martín, Jacobo; Puig, Pere; Canals, Miquel; Company, Joan B.; Amblas, David; Lastras, Galderic; Palanques, Albert; Calafat, Antoni M.

    2013-04-01

    The offshore displacement of bottom trawling fleets has raised concerns over the impact of this human activity on deep-sea ecosystems and associated living resources, which are characterized by a lower resilience than shallow water correlatives. However, the effects of bottom trawling on sediment remobilization across continental margins and on the alteration of seafloor morphology still remain largely unaddressed. We present a compilation of results from studies conducted during the last decade in the La Fonera (Palamós) submarine canyon (NW Mediterranean Sea), where a bottom trawling fishing fleet is active on a daily basis at depths from 400 to 800 m. Deployments of mooring lines equipped with punctual and profiling current-meters, turbidimeters and sediment traps have documented that trawling gears passing along the canyon flanks generate daily sediment gravity flows, implying a periodic sediment removal from fishing grounds. These sediment-laden flows are able to reach the main canyon axis and progress to a minimum depth of 1200 m. Also, sediment accumulation rates in the lower canyon have increased since the industrialization of the local trawling fleet (1970s), suggesting a human-induced enhancement of along-canyon transfer of sediments from the fishing grounds to greater depths. Sedimentological and Pb-210 analysis of interface sediment cores collected from the canyon flanks confirm that widespread erosion and stirring of surface sediments is notable on trawled areas when compared to control (untrawled) sites at similar depths. This chronic reworking and removal of surface sediments from trawling grounds has ultimately led to modifications of the seafloor morphology over large spatial scales, as revealed by high-resolution multibeam bathymetry and Vessel Monitoring Systems (VMS) data sets. Untrawled canyon flank segments are dominated by a dense network of tributary valleys that progress upslope from the main canyon axis, reaching up to five orders of

  7. X-ray selected galaxy clusters in the Pan-STARRS Medium Deep Survey

    NASA Astrophysics Data System (ADS)

    Ebeling, H.; Edge, A. C.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Huber, M. E.; Kaiser, N.; Price, P. A.; Tonry, J. L.

    2013-06-01

    We present the results of a pilot study for the extended Massive Cluster Survey (eMACS), a comprehensive search for distant, X-ray luminous galaxy clusters at z > 0.5. Our pilot study applies the eMACS concept to the 71 deg2 area extended by the 10 fields of the Pan-STARRS1 (PS1) Medium Deep Survey (MDS). Candidate clusters are identified by visual inspection of PS1 images in the g, r, i and z bands in a 5 × 5 arcmin2 region around X-ray sources detected in the ROSAT All-Sky Survey (RASS). To test and optimize the eMACS X-ray selection criteria, our pilot study uses the largest possible RASS data base, i.e. all RASS sources listed in the Bright and Faint Source Catalogues (BSC and FSC) that fall within the MDS footprint. We apply no additional constraints regarding X-ray flux, spectral hardness ratio or photon statistics and lower the redshift threshold to z > 0.3 to extend the probed luminosity range to poorer systems. Scrutiny of PS1/MDS images for 41 BSC and 200 FSC sources combined with dedicated spectroscopic follow-up observations results in a sample of 11 clusters with estimated or spectroscopic redshifts of z > 0.3. In order to assess and quantify the degree of point source contamination of the observed RASS fluxes, we examine archival Chandra data obtained in targeted and serendipitous observations of six of the 11 clusters found. As expected, the diffuse emission from all six systems is contaminated by point sources to some degree, and for half of them active galactic nucleus emission dominates. X-ray follow-up observations will thus be crucial in order to establish robust cluster luminosities for eMACS clusters. Although the small number of distant X-ray luminous clusters in the MDS does not allow us to make firm predictions for the over 20 000 deg2 of extragalactic sky covered by eMACS, the identification of two extremely promising eMACS cluster candidates at z ≳ 0.6 (both yet to be observed with Chandra) in such a small solid angle is encouraging

  8. The Chandra Deep Field North Survey. XV. Optically Bright, X-Ray-Faint Sources

    NASA Astrophysics Data System (ADS)

    Hornschemeier, A. E.; Bauer, F. E.; Alexander, D. M.; Brandt, W. N.; Sargent, W. L. W.; Bautz, M. W.; Conselice, C.; Garmire, G. P.; Schneider, D. P.; Wilson, G.

    2003-08-01

    We have analyzed optically bright, X-ray-faint [OBXF; i.e., log(fX/fR)<~-2] sources identified in an 178.9 arcmin2 area having high exposure (greater than 1500 ks) within the Chandra Deep Field North 2 Ms survey. We find 43 OBXF sources in this area, making up ~15% of the X-ray sources above a 0.5-2 keV flux of ~2.3×10-17 ergs cm-2 s-1. We present spectroscopic identifications for 42 of the OBXF sources and optical spectra for 25, including five previously unpublished redshifts. Deep optical imaging data (either Hubble Space Telescope [HST] or ground-based) are presented for all the OBXF sources; we measure the optical morphologies of the 20 galaxies having HST imaging data. The OBXF population consists mainly of normal and starburst galaxies detected out to cosmologically significant distances (i.e., to a median redshift of z=0.297 and a full redshift range z=0.06-0.845). This is notable since these distances equate to look-back times of up to ~8 Gyr; we are thus provided with a window on the X-ray emission from galaxies at redshifts much closer to the cosmic star formation peak than was possible prior to the Chandra X-Ray Observatory. The X-ray luminosity distribution of OBXF sources extends to higher luminosity than does that of ``normal'' galaxies, indicating that a significant fraction are likely dominated by low-luminosity active galactic nuclei or vigorous star formation. The lowest redshift galaxies (z~0.06-0.2) have very low X-ray-to-optical flux ratios [i.e., log(fX/fR)<~-3], which are consistent with those of normal galaxies in the local universe. By combining the detected X-ray counts, we find the average OBXF X-ray spectrum to be consistent with a Γ~2.0 power law. The 0.5-2 keV logN-logS for the OBXF galaxies is much steeper (α~-1.7) than for the general X-ray source population. Indeed, the number of OBXF sources has doubled between the 1 and 2 Ms surveys, rising sharply in numbers at faint fluxes. The extragalactic OBXF sources are found to

  9. Assessing the deep drilling potential of Lago de Tota, Colombia, with a seismic survey

    NASA Astrophysics Data System (ADS)

    Bird, B. W.; Wattrus, N. J.; Fonseca, H.; Velasco, F.; Escobar, J.

    2015-12-01

    Reconciling orbital-scale patterns of inter-hemispheric South American climate during the Quaternary requires continuous, high-resolution paleoclimate records that span multiple glacial cycles from both hemispheres. Southern Andean Quaternary climates are represented by multi-proxy results from Lake Titicaca (Peru-Bolivia) spanning the last 400 ka and by pending results from the Lago Junin Drilling Project (Peru). Although Northern Andean sediment records spanning the last few million years have been retrieved from the Bogota and Fúquene Basins in the Eastern Cordillera of the Colombian Andes, climatic reconstructions based on these cores have thus far been limited to pollen-based investigations. When viewed together with the Southern Hemisphere results, these records suggest an anti-phased hemispheric climatic response during glacial cycles. In order to better assess orbital-scale climate responses, however, independent temperature and hydroclimate proxies from the Northern Hemisphere are needed in addition to vegetation histories. As part of this objective, an effort is underway to develop a paleoclimate record from Lago de Tota (3030 m asl), the largest lake in Colombia and the third largest lake in the Andes. One of 17 highland tectonic basins in Eastern Cordillera, Lago de Tota formed during Tertiary uplift that deformed pre-foreland megasequences, synrift and back-arc megasequences. The precise age and thickness of sediments in the Lago de Tota basin has not previously been established. Here, we present results from a recent single-channel seismic reflection survey collected with a small (5 cubic inch) air gun and high-resolution CHIRP sub-bottom data. With these data, we examine the depositional history and sequence stratigraphy of Lago de Tota and assess its potential as a deep drilling target.

  10. A Rapid Radiocarbon Method for Age Surveys of Southern Ocean Deep-sea Corals

    NASA Astrophysics Data System (ADS)

    Burke, A.; Robinson, L. F.; Gerlach, D. S.; Jenkins, W. J.; McNichol, A. P.

    2008-12-01

    Deep-sea corals provide a unique archive of past ocean radiocarbon because they are sessile and can be dated independently using U-series nuclides. One difficulty, however, is that using current techniques it is impractical to date large numbers of corals in order to determine which specimens have the appropriate ages for radiocarbon reconstructions. Here we present results from a quick method of making graphite for radiocarbon dating that reduces the amount of sample preparation time, thus allowing us to date a greater number of corals. In addition, these rapid age surveys provide important information on coral age populations, allowing us to examine coral distributions through time. The corals used in this study come from a sample set of about 6,000 specimens of Flabellum, Balanophyllia and Desmophyllum spp. collected from the Drake Passage area (50S -70S, 120 m-1700 m depth). Replicate samples from a single coral yielded a standard deviation of 81 years (n=9). Variations in sample mass (3 to 85 mg) have no clear effect on the Fm and furthermore, a simple cleaning using methanol yields the same results as a more involved cleaning procedure that includes an oxidizing solution and perchloric acid rinse. To improve the efficiency of the method, we assumed a delta13C = 0 per mil. This assumption is likely our largest source of uncertainty, resulting in offsets of up to 200 radiocarbon years over a reasonable range of delta13C. This level of uncertainty is sufficiently low to allow distinction between corals from different time periods over the past 35 ky (e.g. Last Glacial Maximum, Younger Dryas, etc.). To date, we have found corals from Burdwood Bank dating from the modern to the Younger Dryas and corals from the Drake Passage dating from the modern to Heinrich Event 1, which will be used in future paleo-climatic reconstructions in this important part of the ocean.