41
41
Sep 19, 2013
09/13
by
B. D. Lehmer; D. M. Alexander; F. E. Bauer; W. N. Brandt; A. D. Goulding; L. P. Jenkins; A. Ptak; T. P. Roberts
texts
eye 41
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We present new Chandra observations that complete a sample of seventeen (17) luminous infrared galaxies (LIRGs) with D < 60 Mpc and low Galactic column densities of N_H < 5 X 10^20 cm^-2. The LIRGs in our sample have total infrared (8-1000um) luminosities in the range of L_IR ~ (1-8) X 10^11 L_sol. The high-resolution imaging and X-ray spectral information from our Chandra observations allow us to measure separately X-ray contributions from active galactic nuclei (AGNs) and normal galaxy...
Source: http://arxiv.org/abs/1009.3943v1
11
11
Jun 27, 2018
06/18
by
C. Saez; B. D. Lehmer; F. E. Bauer; D. Stern; A. Gonzales; I. Rreza; D. M. Alexander; Y. Matsuda; J. E. Geach; F. A. Harrison; T. Havashino
texts
eye 11
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We present VLT VIMOS, Keck DEIMOS and Keck LRIS multi-object spectra of 367 sources in the field of the z ~ 3.09 protocluster SSA22. Sources are spectroscopically classified via template matching, allowing new identifications for 206 extragalactic sources, including 36 z > 2 Lyman-break galaxies (LBGs) and Lyman-\alpha\ emitters (LAEs), 8 protocluster members, and 94 X-ray sources from the ~ 400 ks Chandra deep survey of SSA22. Additionally, in the area covered by our study, we have...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1504.00737
13
13
Jun 28, 2018
06/18
by
N. K. Hine; J. E. Geach; D. M. Alexander; B. D. Lehmer; S C. Chapman; Y. Matsuda
texts
eye 13
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The over-dense environments of protoclusters of galaxies in the early Universe (z>2) are expected to accelerate the evolution of galaxies, with an increased rate of stellar mass assembly and black hole accretion compared to co-eval galaxies in the average density `field'. These galaxies are destined to form the passive population of massive systems that dominate the cores of rich clusters today. While signatures of accelerated growth of galaxies in the SSA22 protocluster (z=3.1) have been...
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1506.05115
50
50
Sep 21, 2013
09/13
by
M. A. Worsley; A. C. Fabian; F. E. Bauer; D. M. Alexander; W. N. Brandt; B. D. Lehmer
texts
eye 50
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The emission from individual X-ray sources in the Chandra Deep Fields and XMM-Newton Lockman Hole shows that almost half of the hard X-ray background above 6 keV is unresolved and implies the existence of a missing population of heavily obscured active galactic nuclei (AGN). We have stacked the 0.5-8 keV X-ray emission from optical sources in the Great Observatories Origins Deep Survey (GOODS; which covers the Chandra Deep Fields) to determine whether these galaxies, which are individually...
Source: http://arxiv.org/abs/astro-ph/0602605v1
67
67
Sep 18, 2013
09/13
by
A. T. Steffen; W. N. Brandt; D. M. Alexander; S. C. Gallagher; B. D. Lehmer
texts
eye 67
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We employ X-ray stacking techniques to examine the contribution from X-ray undetected, mid-infrared-selected sources to the unresolved, hard (6-8 keV) cosmic X-ray background (CXB). We use the publicly available, 24 micron Spitzer Space Telescope MIPS catalogs from the Great Observatories Origins Deep Survey (GOODS) - North and South fields, which are centered on the 2 Ms Chandra Deep Field-North and the 1 Ms Chandra Deep Field-South, to identify bright (S_24 > 80 microJy) mid-infrared...
Source: http://arxiv.org/abs/0705.2213v1
73
73
Jul 20, 2013
07/13
by
Y. Q. Xue; W. N. Brandt; B. Luo; D. A. Rafferty; D. M. Alexander; F. E. Bauer; B. D. Lehmer; D. P. Schneider; J. D. Silverman
texts
eye 73
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[Abridged] We extend color-magnitude relations for moderate-luminosity X-ray AGN hosts and non-AGN galaxies through the galaxy formation epoch in the Chandra Deep Fields. We utilized analyses of color-magnitude diagrams (CMDs) to assess the role of moderate-luminosity AGNs in galaxy evolution. First, we confirm some previous results and extend them to higher redshifts, e.g., there is no apparent color bimodality for AGN hosts from z~0-2, but non-AGN galaxy color bimodality exists up to z~3;...
Source: http://arxiv.org/abs/1007.1453v1
55
55
Sep 21, 2013
09/13
by
B. D. Lehmer; A. B. Lucy; D. M. Alexander; P. N. Best; J. E. Geach; C. M. Harrison; A. E. Hornschemeier; Y. Matsuda; J. R. Mullaney; Ian Smail; D. Sobral; A. M. Swinbank
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eye 55
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We present results from a ~100 ks Chandra observation of the 2QZ Cluster 1004+00 structure at z = 2.23 (hereafter, 2QZ Clus). 2QZ Clus was originally identified as an overdensity of four optically-selected QSOs at z = 2.23 within a 15x15 arcmin^2 region. Narrow-band imaging in the near-IR revealed that the structure contains an additional overdensity of 22 z = 2.23 Halpha-emitting galaxies (HAEs), resulting in 23 unique z = 2.23 HAEs/QSOs. Our Chandra observations reveal that 3 HAEs in addition...
Source: http://arxiv.org/abs/1301.3922v1
63
63
Sep 23, 2013
09/13
by
C. Saez; G. Chartas; W. N. Brandt; B. D. Lehmer; F. E. Bauer; X. Dai; G. P. Garmire
texts
eye 63
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We present results from a statistical analysis of 173 bright radio-quiet AGNs selected from the Chandra Deep Field-North and Chandra Deep Field-South surveys (hereafter, CDFs) in the redshift range of 0.1 < z < 4. We find that the X-ray power-law photon index (Gamma) of radio-quiet AGNs is correlated with their 2-10 keV rest-frame X-ray luminosity (L_X) at the > 99.5 percent confidence level in two redshift bins, 0.3 < z < 0.96, and 1.5 < z < 3.3 and is slightly less...
Source: http://arxiv.org/abs/0801.3599v1
47
47
Sep 21, 2013
09/13
by
B. Luo; W. N. Brandt; J. D. Silverman; I. V. Strateva; F. E. Bauer; P. Capak; J. Kartaltepe; B. D. Lehmer; V. Mainieri; M. Salvato; G. Szokoly; D. P. Schneider; C. Vignali
texts
eye 47
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We report the discovery of the most-distant double-peaked emitter, CXOECDFS J033115.0-275518, at z=1.369. A Keck/DEIMOS spectrum shows a clearly double-peaked broad Mg II $\lambda2799$ emission line, with FWHM 11000 km/s for the line complex. The line profile can be well fit by an elliptical relativistic Keplerian disk model. This is one of a handful of double-peaked emitters known to be a luminous quasar, with excellent multiwavelength coverage and a high-quality X-ray spectrum. CXOECDFS...
Source: http://arxiv.org/abs/0901.2929v1
48
48
Sep 20, 2013
09/13
by
B. Luo; W. N. Brandt; Y. Q. Xue; M. Brusa; D. M. Alexander; F. E. Bauer; A. Comastri; A. Koekemoer; B. D. Lehmer; V. Mainieri; D. A. Rafferty; D. P. Schneider; J. D. Silverman; C. Vignali
texts
eye 48
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[Abridged] We present reliable multiwavelength identifications and high-quality photometric redshifts for the 462 X-ray sources in the ~2 Ms Chandra Deep Field-South. Source identifications are carried out using deep optical-to-radio multiwavelength catalogs, and are then combined to create lists of primary and secondary counterparts for the X-ray sources. We identified reliable counterparts for 446 (96.5%) of the X-ray sources, with an expected false-match probability of ~6.2%. A...
Source: http://arxiv.org/abs/1002.3154v2
47
47
Sep 22, 2013
09/13
by
Ian Smail; Katherine M. Blundell; B. D. Lehmer; D. M. Alexander
texts
eye 47
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We report the detection of extended X-ray emission around two powerful high-z radio galaxies (HzRGs) at z~3.6 (4C03.24 & 4C19.71) and use these to investigate the origin of extended, Inverse Compton (IC) powered X-ray halos at high z. The halos have X-ray luminosities of Lx~3e44 erg/s and sizes of ~60kpc. Their morphologies are broadly similar to the ~60-kpc long radio lobes around these galaxies suggesting they are formed from IC scattering by relativistic electrons in the radio lobes, of...
Source: http://arxiv.org/abs/1210.4548v1
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54
Sep 18, 2013
09/13
by
C. Gronwall; R. Ciardullo; T. Hickey; E. Gawaiser; J. J. Feldmeier; P. G. van Dokkum; C. M. Urry; D. Herrera; B. D. Lehmer; L. Infante; A. Orsi; D. Marchesini; G. A. Blanc; H. Francke; P. Lira; E. Treister
texts
eye 54
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We describe the results of an extremely deep, 0.28 deg^2 survey for z = 3.1 Ly-alpha emission-line galaxies in the Extended Chandra Deep Field South. By using a narrow-band 5000 Anstrom filter and complementary broadband photometry from the MUSYC survey, we identify a statistically complete sample of 162 galaxies with monochromatic fluxes brighter than 1.5 x 10^-17 ergs cm^-2 s^-1 and observers frame equivalent widths greater than 80 Angstroms. We show that the equivalent width distribution of...
Source: http://arxiv.org/abs/0705.3917v1
80
80
Sep 22, 2013
09/13
by
M. Tremmel; T. Fragos; B. D. Lehmer; P. Tzanavaris; K. Belczynski; V. Kalogera; A. R. Basu-Zych; W. M. Farr; A. Hornschemeier; L. Jenkins; A. Ptak; A. Zezas
texts
eye 80
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Emission from X-ray binaries (XRBs) is a major component of the total X-ray luminosity of normal galaxies, so X-ray studies of high redshift galaxies allow us to probe the formation and evolution of X-ray binaries on very long timescales. In this paper, we present results from large-scale population synthesis models of binary populations in galaxies from z = 0 to 20. We use as input into our modeling the Millennium II Cosmological Simulation and the updated semi-analytic galaxy catalog by Guo...
Source: http://arxiv.org/abs/1210.7185v3
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40
Sep 19, 2013
09/13
by
Y. Tamura; D. Iono; D. J. Wilner; M. Kajisawa; Y. K. Uchimoto; D. M. Alexander; A. Chung; H. Ezawa; B. Hatsukade; T. Hayashino; D. H. Hughes; T. Ichikawa; S. Ikarashi; R. Kawabe; K. Kohno; B. D. Lehmer; Y. Matsuda; K. Nakanishi; T. Takata; G. W. Wilson; T. Yamada; M. S. Yun
texts
eye 40
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We present results from Submillimeter Array (SMA) 860-micron sub-arcsec astrometry and multiwavelength observations of the brightest millimeter (S_1.1mm = 8.4 mJy) source, SSA22-AzTEC1, found near the core of the SSA22 protocluster that is traced by Ly\alpha emitting galaxies at z = 3.09. We identify a 860-micron counterpart with a flux density of S_860um = 12.2 +/- 2.3 mJy and absolute positional accuracy that is better than 0.3". At the SMA position, we find radio to mid-infrared...
Source: http://arxiv.org/abs/1010.1267v1
51
51
Sep 21, 2013
09/13
by
D. A. Rafferty; W. N. Brandt; D. M. Alexander; Y. Q. Xue; F. E. Bauer; B. D. Lehmer; B. Luo; C. Papovich
texts
eye 51
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We present an analysis of deep multiwavelength data for z ~ 0.3-3 starburst galaxies selected by their 70 um emission in the Extended-Chandra Deep Field-South and Extended Groth Strip. We identify active galactic nuclei (AGNs) in these infrared sources through their X-ray emission and quantify the fraction that host an AGN. We find that the fraction depends strongly on both the mid-infrared color and rest-frame mid-infrared luminosity of the source, rising to ~ 50-70% at the warmest colors and...
Source: http://arxiv.org/abs/1108.3229v1
10
10.0
Jun 27, 2018
06/18
by
B. D. Lehmer; J. B. Tyler; A. E. Hornschemeier; D. R. Wik; M. Yukita; V. Antoniou; S. Boggs; F. E. Christensen; W. W. Craig; C. J. Hailey; F. A. Harrison; T. J. Maccarone; A. Ptak; D. Stern; A. Zezas; W. W. Zhang
texts
eye 10
favorite 0
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We present nearly simultaneous Chandra and NuSTAR observations of two actively star-forming galaxies within 50 Mpc: NGC 3256 and NGC 3310. Both galaxies are detected by both Chandra and NuSTAR, which together provide the first-ever spectra of these two galaxies spanning 0.3-30 keV. The X-ray emission from both galaxies is spatially resolved by Chandra; we find that hot gas dominates the E < 1-3 keV emission while ultraluminous X-ray sources (ULXs) dominate at E > 1-3 keV. The NuSTAR...
Topics: High Energy Astrophysical Phenomena, Astrophysics, Cosmology and Nongalactic Astrophysics,...
Source: http://arxiv.org/abs/1505.00789
49
49
Sep 21, 2013
09/13
by
B. D. Lehmer; Y. Q. Xue; W. N. Brandt; D. M. Alexander; F. E. Bauer; M. Brusa; A. Comastri; R. Gilli; A. E. Hornschemeier; B. Luo; M. Paolillo; A. Ptak; O. Shemmer; D. P. Schneider; P. Tozzi; C. Vignali
texts
eye 49
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We present 0.5-2 keV, 2-8 keV, 4-8 keV, and 0.5-8 keV cumulative and differential number counts (logN-logS) measurements for the recently completed ~4 Ms Chandra Deep Field-South (CDF-S) survey, the deepest X-ray survey to date. We implement a new Bayesian approach, which allows reliable calculation of number counts down to flux limits that are factors of ~1.9-4.3 times fainter than the previously deepest number-counts investigations. In the soft band, the most sensitive bandpass in our...
Source: http://arxiv.org/abs/1204.1977v1
57
57
Sep 23, 2013
09/13
by
Y. Q. Xue; B. Luo; W. N. Brandt; F. E. Bauer; B. D. Lehmer; P. S. Broos; D. P. Schneider; D. M. Alexander; M. Brusa; A. Comastri; A. C. Fabian; R. Gilli; G. Hasinger; A. E. Hornschemeier; A. Koekemoer; T. Liu; V. Mainieri; M. Paolillo; D. A. Rafferty; P. Rosati; O. Shemmer; J. D. Silverman; I. Smail; P. Tozzi; C. Vignali
texts
eye 57
favorite 1
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[abridged] We present point-source catalogs for the 4Ms Chandra Deep Field-South (CDF-S), which is the deepest Chandra survey to date and covers an area of 464.5 arcmin^2. We provide a main source catalog, which contains 740 X-ray point sources that are detected with wavdetect at a false-positive probability threshold of 1E-5 and also satisfy a binomial-probability source-selection criterion of P
Source: http://arxiv.org/abs/1105.5643v1
48
48
Sep 18, 2013
09/13
by
B. D. Lehmer; D. M. Alexander; J. E. Geach; Ian Smail; A. Basu-Zych; F. E. Bauer; S. C. Chapman; Y. Matsuda; C. A. Scharf; M. Volonteri; T. Yamada
texts
eye 48
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We present results from a new ultra-deep 400 ks Chandra observation of the SSA22 protocluster at z = 3.09. We have studied the X-ray properties of 234 z ~ 3 Lyman break galaxies (LBGs; protocluster and field) and 158 z = 3.09 Ly-alpha emitters (LAEs) in SSA22 to measure the influence of the high-density protocluster environment on the accretion activity of supermassive black holes (SMBHs) in these UV-selected star forming populations. We detect individually X-ray emission from active galactic...
Source: http://arxiv.org/abs/0809.5058v1
58
58
Sep 23, 2013
09/13
by
J. E. Geach; D. M. Alexander; B. D. Lehmer; Ian Smail; Y. Matsuda; S. C. Chapman; C. A. Scharf; R. J. Ivison; M. Volonteri; T. Yamada; A. W. Blain; R. G. Bower; F. E. Bauer; A. Basu-Zych
texts
eye 58
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We present the results of a 400ks Chandra survey of 29 extended Ly-alpha emitting nebulae (Ly-alpha Blobs, LABs) in the z=3.09 proto-cluster in the SSA22 field. We detect luminous X-ray counterparts in five LABs, implying a large fraction of active galactic nuclei (AGN) in LABs, f_AGN = 17% down to L_2-32keV ~ 10^44 erg/s. All of the AGN appear to be heavily obscured, with spectral indices implying obscuring column densities of N_H > 10^23 cm^-2. The AGN fraction should be considered a lower...
Source: http://arxiv.org/abs/0904.0452v3
55
55
Sep 21, 2013
09/13
by
J. D. Silverman; V. Mainieri; B. D. Lehmer; D. M. Alexander; F. E. Bauer; J. Bergeron; W. N. Brandt; R. Gilli; G. Hasinger; D. P. Schneider; P. Tozzi; C. Vignali; A. M. Koekemoer; T. Miyaji; P. Popesso; P. Rosati; G. Szokoly
texts
eye 55
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We present an analysis of 109 moderate-luminosity (41.9 < Log L{0.5-8.0 keV} < 43.7) AGN in the Extended Chandra Deep Field-South survey, which is drawn from 5,549 galaxies from the COMBO-17 and GEMS surveys having 0.4 < z < 1.1. These obscured or optically-weak AGN facilitate the study of their host galaxies since the AGN provide an insubstantial amount of contamination to the galaxy light. We find that the color distribution of AGN host galaxies is highly dependent upon (1) the...
Source: http://arxiv.org/abs/0709.3455v2
48
48
Sep 20, 2013
09/13
by
B. D. Lehmer; W. N. Brandt; D. M. Alexander; F. E. Bauer; D. P. Schneider; P. Tozzi; J. Bergeron; G. P. Garmire; R. Giacconi; R. Gilli; G. Hasinger; A. E. Hornschemeier; A. M. Koekemoer; V. Mainieri; T. Miyaji; M. Nonino; P. Rosati; J. D. Silverman; G. Szokoly; C. Vignali
texts
eye 48
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We present Chandra point-source catalogs for the Extended Chandra Deep Field-South (E-CDF-S) survey. The E-CDF-S consists of four contiguous 250 ks Chandra observations covering an approximately square region of total solid angle ~0.3 deg^2, which flank the existing ~1 Ms Chandra Deep Field-South (CDF-S). The survey reaches sensitivity limits of 1.1 X 10^-16 erg/cm^2/s and 6.7 X 10^-16 erg/cm^2/s for the 0.5-2.0 keV and 2-8 keV bands, respectively. We detect 762 distinct X-ray point sources...
Source: http://arxiv.org/abs/astro-ph/0506607v2
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45
Sep 19, 2013
09/13
by
J. D. Silverman; V. Mainieri; M. Salvato; G. Hasinger; J. Bergeron; P. Capak; G. Szokoly; A. Finoguenov; R. Gilli; P. Rosati; P. Tozzi; C. Vignali; D. M. Alexander; W. N. Brandt; B. D. Lehmer; B. Luo; D. Rafferty; Y. Q. Xue; I. Balestra; F. E. Bauer; M. Brusa; A. Comastri; J. Kartaltepe; A. M. Koekemoer; T. Miyaji; D. P. Schneider; E. Treister; L. Wisotski; M. Schramm
texts
eye 45
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We present the results of a program to acquire high-quality optical spectra of X-ray sources detected in the E-CDF-S and its central area. New spectroscopic redshifts are measured for 283 counterparts to Chandra sources with deep exposures (t~2-9 hr per pointing) using multi-slit facilities on both the VLT and Keck thus bringing the total number of spectroscopically-identified X-ray sources to over 500 in this survey field. We provide a comprehensive catalog of X-ray sources detected in the...
Source: http://arxiv.org/abs/1009.1923v1
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52
Sep 21, 2013
09/13
by
B. D. Lehmer; W. N. Brandt; A. E. Hornschemeier; D. M. Alexander; F. E. Bauer; A. M. Koekemoer; D. P. Schneider; A. T. Steffen
texts
eye 52
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We analyze a population of intermediate-redshift (z ~ 0.05-0.3), off-nuclear X-ray sources located within optically-bright galaxies in the Great Observatories Origins Deep Survey (GOODS) and Galaxy Evolution from Morphology and SEDs (GEMS) fields. A total of 24 off-nuclear source candidates are classified using deep Chandra exposures from the Chandra Deep Field-North, Chandra Deep Field-South, and Extended Chandra Deep Field-South; 15 of these are newly identified. These sources have average...
Source: http://arxiv.org/abs/astro-ph/0602001v1
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70
Sep 21, 2013
09/13
by
P. Tozzi; V. Mainieri; P. Rosati; P. Padovani; K. I. Kellermann; E. Fomalont; N. Miller; P. Shaver; J. Bergeron; W. N. Brandt; M. Brusa; R. Giacconi; G. Hasinger; B. D. Lehmer; M. Nonino; C. Norman; J. Silverman
texts
eye 70
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We discuss the X-ray properties of the radio sources detected in a deep 1.4 and 5 GHz VLA Radio survey of the Extended Chandra Deep Field South (E-CDFS). Among the 266 radio sources detected, we find 89 sources (1/3 of the total) with X-ray counterparts in the catalog of the 1Ms exposure of the central 0.08 deg^2 (Giacconi et al. 2002; Alexander et al. 2003) or in the catalog of the 250 ks exposure of the 0.3 deg^2 E-CDFS field (Lehmer et al. 2005). For 76 (85%) of these sources we have...
Source: http://arxiv.org/abs/0902.2930v1
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49
Sep 20, 2013
09/13
by
B. D. Lehmer; W. N. Brandt; D. M. Alexander; E. F. Bell; D. H. McIntosh; F. E. Bauer; G. Hasinger; V. Mainieri; T. Miyaji; D. P. Schneider; A. T. Steffen
texts
eye 49
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We investigate the evolution over the last 6.3 Gyr of cosmic time (i.e., since z ~ 0.7) of the average X-ray properties of early-type galaxies within the Extended Chandra Deep Field-South (E-CDF-S). Our early-type galaxy sample includes 539 objects with red-sequence colors and Sersic indices larger than n = 2.5, which were selected jointly from the COMBO-17 (Classifying Objects by Medium-Band Observations in 17 Filters) and GEMS (Galaxy Evolution from Morphologies and SEDs) surveys. We utilize...
Source: http://arxiv.org/abs/astro-ph/0612003v1
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57
Sep 21, 2013
09/13
by
A. T. Steffen; I. Strateva; W. N. Brandt; D. M. Alexander; A. M. Koekemoer; B. D. Lehmer; D. P. Schneider; C. Vignali
texts
eye 57
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We present partial-correlation analyses that examine the strengths of the relationships between L_UV, L_X, Alpha_OX, and redshift for optically-selected AGNs. We extend the work of Strateva et al. (2005), that analyzed optically-selected AGNs from the Sloan Digital Sky Survey (SDSS), by including 52 moderate-luminosity, optically-selected AGNs from the COMBO-17 survey with corresponding deep (~250 ks to 1 Ms) X-ray observations from the Extended Chandra Deep Field-South. The COMBO-17 survey...
Source: http://arxiv.org/abs/astro-ph/0602407v1
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48
Sep 18, 2013
09/13
by
B. D. Lehmer; W. N. Brandt; D. M. Alexander; E. F. Bell; A. E. Hornschemeier; D. H. McIntosh; F. E. Bauer; R. Gilli; V. Mainieri; D. P. Schneider; J. D. Silverman; A. T. Steffen; P. Tozzi; C. Wolf
texts
eye 48
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We report on the X-ray evolution over the last ~9 Gyr of cosmic history (i.e., since z = 1.4) of late-type galaxy populations in the Chandra Deep Field-North and Extended Chandra Deep Field-South (CDF-N and E-CDF-S, respectively; jointly CDFs) survey fields. Our late-type galaxy sample consists of 2568 galaxies, which were identified using rest-frame optical colors and HST morphologies. We utilized X-ray stacking analyses to investigate the X-ray emission from these galaxies, emphasizing the...
Source: http://arxiv.org/abs/0803.3620v2
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36
Sep 18, 2013
09/13
by
Y. Q. Xue; S. X. Wang; W. N. Brandt; B. Luo; D. M. Alexander; F. E. Bauer; A. Comastri; A. C. Fabian; R. Gilli; B. D. Lehmer; D. P. Schneider; C. Vignali; M. Young
texts
eye 36
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Using the 4 Ms Chandra Deep Field-South (CDF-S) survey, we have identified a sample of 6845 X-ray undetected galaxies that dominates the unresolved ~ 20-25% of the 6-8 keV cosmic X-ray background (XRB). This sample was constructed by applying mass and color cuts to sources from a parent catalog based on GOODS-South HST z-band imaging of the central 6'-radius area of the 4 Ms CDF-S. The stacked 6-8 keV detection is significant at the 3.9 sigma level, but the stacked emission was not detected in...
Source: http://arxiv.org/abs/1209.0467v1
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47
Sep 18, 2013
09/13
by
M. Young; W. N. Brandt; Y. Q. Xue; M. Paolillo; D. M. Alexander; F. E. Bauer; B. D. Lehmer; B. Luo; O. Shemmer; D. P. Schneider; C. Vignali
texts
eye 47
favorite 1
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The 4 Ms Chandra Deep Field-South (CDF-S) and other deep X-ray surveys have been highly effective at selecting active galactic nuclei (AGN). However, cosmologically distant low-luminosity AGN (LLAGN) have remained a challenge to identify due to significant contribution from the host galaxy. We identify long-term X-ray variability (~month-years, observed frame) in 20 of 92 CDF-S galaxies spanning redshifts z~0.08-1.02 that do not meet other AGN selection criteria. We show that the observed...
Source: http://arxiv.org/abs/1201.4391v1
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61
Sep 22, 2013
09/13
by
B. D. Lehmer; W. N. Brandt; D. M. Alexander; F. E. Bauer; C. J. Conselice; M. E. Dickinson; M. Giavalisco; N. A. Grogin; A. M. Koekemoer; K. S. Lee; L. A. Moustakas; D. P. Schneider
texts
eye 61
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We constrain the X-ray emission properties of Lyman break galaxies (LBGs) at z ~ 3-6 using the 2 Ms Chandra Deep Field-North and 1 Ms Chandra Deep Field-South. Large samples of LBGs were discovered using HST as part of the Great Observatories Origins Deep Survey (GOODS). Deep optical and X-ray imaging over the GOODS fields have allowed us to place the most significant constraints on the X-ray properties of LBGs to date. Mean X-ray properties of 449, 1734, 629, and 247 LBGs with z ~ 3, 4, 5, and...
Source: http://arxiv.org/abs/astro-ph/0409600v1
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Sep 21, 2013
09/13
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D. M. Alexander; F. E. Bauer; W. N. Brandt; E. Daddi; R. C. Hickox; B. D. Lehmer; B. Luo; Y. Q. Xue; M. Young; A. Comastri; A. Del Moro; A. C. Fabian; R. Gilli; A. D. Goulding; V. Mainieri; J. R. Mullaney; M. Paolillo; D. A. Rafferty; D. P. Schneider; O. Shemmer; C. Vignali
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We use the 4Ms CDF-S survey to place direct X-ray constraints on the ubiquity of z~2 heavily obscured AGNs in K 1E43 erg/s) heavily obscured and Compton-thick AGNs at z~2. Our space-density constraints are conservative lower limits but they are already consistent with the range of predictions from X-ray background models.
Source: http://arxiv.org/abs/1106.1443v1
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Sep 23, 2013
09/13
by
W. N. Brandt; C. Vignali; B. D. Lehmer; L. A. Lopez; D. P. Schneider; I. V. Strateva
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We briefly review some recent results from Chandra and XMM-Newton studies of the highest redshift (z > 4) active galactic nuclei (AGNs). Specific topics covered include radio-quiet quasars, radio-loud quasars, moderate-luminosity AGNs in X-ray surveys, and future prospects. No significant changes in AGN X-ray emission properties have yet been found at high redshift, indicating that the small-scale X-ray emission regions of AGNs are insensitive to the dramatic changes on larger scales that...
Source: http://arxiv.org/abs/astro-ph/0411355v1
