3
3.0
Jun 28, 2018
06/18
by
M. Mezcua; F. Civano; G. Fabbiano; T. Miyaji; S. Marchesi
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We study a sample of $\sim$50,000 dwarf starburst and late-type galaxies drawn from the COSMOS survey with the aim of investigating the presence of nuclear accreting black holes (BHs) as those seed BHs from which supermassive BHs could grow in the early Universe. We divide the sample into five complete redshift bins up to $z=1.5$ and perform an X-ray stacking analysis using the \textit{Chandra} COSMOS-Legacy survey data. After removing the contribution from X-ray binaries and hot gas to the...
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1511.05844
4
4.0
Jun 29, 2018
06/18
by
F. Ricci; S. Marchesi; F. Shankar; F. La Franca; F. Civano
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The cosmological process of hydrogen (HI) reionization in the intergalactic medium is thought to be driven by UV photons emitted by star-forming galaxies and ionizing active galactic nuclei (AGN). The contribution of QSOs to HI reionization at $z>4$ has been traditionally believed to be quite modest. However, this view has been recently challenged by new estimates of a higher faint-end UV luminosity function (LF). To set firmer constraints on the emissivity of AGN at $z
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1610.01638
6
6.0
Jun 29, 2018
06/18
by
N. Baran; V. Smolčić; M. Novak; J. Delhaize; I. Delvecchio; P. Capak; F. Civano; N. Herrera-Ruiz; O. Ilbert; C. Laigle; S. Marchesi; H. J. McCracken; E. Middelberg; M. Salvato; E. Schinnerer
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eye 6
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We study the composition of the faint radio population selected from the VLA-COSMOS 3GHz Large Project, a radio continuum survey performed at 10 cm wavelength. The survey covers the full 2 square degree COSMOS field with mean $rms\sim2.3$ $\mu$Jy/beam, cataloging 10,899 source components above $5\times rms$. By combining these radio data with UltraVISTA, optical, near-infrared, and Spitzer/IRAC mid-infrared data, as well as X-ray data from the Chandra Legacy, and Chandra COSMOS surveys, we gain...
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1603.05996
8
8.0
Jun 29, 2018
06/18
by
S. Marchesi; G. Lanzuisi; F. Civano; K. Iwasawa; H. Suh; A. Comastri; G. Zamorani; V. Allevato; R. Griffiths; T. Miyaji; P. Ranalli; M. Salvato; K. Schawinski; J. Silverman; E. Treister; C. M. Urry; C. Vignali
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eye 8
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We present the X-ray spectral analysis of the 1855 extragalactic sources in the Chandra COSMOS-Legacy survey catalog having more than 30 net counts in the 0.5-7 keV band. 38% of the sources are optically classified Type 1 active galactic nuclei (AGN), 60% are Type 2 AGN and 2% are passive, low-redshift galaxies. We study the distribution of AGN photon index and of the intrinsic absorption N(H,z) based on the sources optical classification: Type 1 have a slightly steeper mean photon index than...
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1608.05149
3
3.0
Jun 29, 2018
06/18
by
V. Allevato; F. Civano; A. Finoguenov; S. Marchesi; F. Shankar; G. Zamorani; G. Hasinger; M. Salvato; T. Miyaji; R. Gilli; N. Cappelluti; M. Brusa; H. Suh; G. Lanzuisi; B. Trakhtenbrot; R. Griffiths; C. Vignali; K. Schawinski; A. Karim
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We present the measurement of the projected and redshift space 2-point correlation function (2pcf) of the new catalog of Chandra COSMOS-Legacy AGN at 2.9$\leq$z$\leq$5.5 ($\langle L_{bol} \rangle \sim$10$^{46}$ erg/s) using the generalized clustering estimator based on phot-z probability distribution functions (Pdfs) in addition to any available spec-z. We model the projected 2pcf estimated using $\pi_{max}$ = 200 h$^{-1}$ Mpc with the 2-halo term and we derive a bias at z$\sim$3.4 equal to b =...
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1609.02553
7
7.0
Jun 29, 2018
06/18
by
S. Marchesi; F. Civano; M. Salvato; F. Shankar; A. Comastri; M. Elvis; G. Lanzuisi; B. Trakhtenbrot; C. Vignali; G. Zamorani; V. Allevato; M. Brusa; F. Fiore; R. Gilli; R. Griffiths; G. Hasinger; T. Miyaji; K. Schawinski; E. Treister; C. M. Urry
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We present the largest high-redshift (30 at z>3. We compute the number counts in the observed 0.5-2 keV band, finding a decline in the number of sources at z>3 and constraining phenomenological models of X-ray background. We compute the AGN space density at z>3 in two different luminosity bins. At higher luminosities (logL(2-10 keV) > 44.1 erg/s) the space density declines exponentially, dropping by a factor ~20 from z~3 to z~6. The observed decline is ~80% steeper at lower...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1606.06813
3
3.0
Jun 29, 2018
06/18
by
V. Smolcic; O. Miettinen; N. Tomicic; G. Zamorani; A. Finoguenov; B. C. Lemaux; M. Aravena; P. Capak; Y-K. Chiang; F. Civano; I. Delvecchio; O. Ilbert; N. Jurlin; A. Karim; C. Laigle; O. Le Fevre; S. Marchesi; H. J. McCracken; D. A. Riechers; M. Salvato; E. Schinnerer; L. Tasca; S. Toft
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We study the environment of 23 submillimetre galaxies (SMGs) drawn from the JCMT/AzTEC 1.1mm S/N-limited sample in the COSMOS field, as well as 4 COSMOS SMGs at z_spec>4.5, and 1 at z_spec=2.49, yielding a sample of 28 SMGs. We search for overdensities using the COSMOS photometric redshifts based on over 30 UV-NIR photometric bands, reaching an accuracy of sigma(Delta z/(1+z))=0.0067 (0.0155) at z 3.5). To identify overdensities we apply the Voronoi tessellation analysis, and estimate the...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1604.01775
3
3.0
Jun 30, 2018
06/18
by
G. Lanzuisi; P. Ranalli; I. Georgantopoulos; A. Georgakakis; I. Delvecchio; T. Akylas; S. Berta; A. Bongiorno; M. Brusa; N. Cappelluti; F. Civano; A. Comastri; R. Gilli; C. Gruppioni; G. Hasinger; K. Iwasawa; A. Koekemoer; E. Lusso; S. Marchesi; V. Mainieri; A. Merloni; M. Mignoli; E. Piconcelli; F. Pozzi; D. J. Rosario; M. Salvato; J. Silverman; B. Trakhtenbrot; C. Vignali; G. Zamorani
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Heavily obscured, Compton Thick (CT, NH>10^24 cm^-2) AGN may represent an important phase in AGN/galaxy co-evolution and are expected to provide a significant contribution to the cosmic X-ray background (CXB). Through direct X-ray spectra analysis, we selected 39 heavily obscured AGN (NH>3x10^23 cm^-2) in the 2 deg^2 XMM-COSMOS survey. After selecting CT AGN based on the fit of a simple absorbed two power law model to the XMM data, the presence of CT AGN was confirmed in 80% of the...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1409.1867
5
5.0
Jun 28, 2018
06/18
by
S. Marchesi; F. Civano; M. Elvis; M. Salvato; M. Brusa; A. Comastri; R. Gilli; G. Hasinger; G. Lanzuisi; T. Miyaji; E. Treister; C. M. Urry; C. Vignali; G. Zamorani; V. Allevato; N. Cappelluti; C. Cardamone; A. Finoguenov; R. E. Griffiths; A. Karim; C. Laigle; S. M. LaMassa; K. Jahnke; P. Ranalli; K. Schawinski; E. Schinnerer; J. D. Silverman; V. Smolcic; H. Suh; B. Trakhtenbrot
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We present the catalog of optical and infrared counterparts of the Chandra COSMOS-Legacy Survey, a 4.6 Ms Chandra program on the 2.2 square degrees of the COSMOS field, combination of 56 new overlapping observations obtained in Cycle 14 with the previous C-COSMOS survey. In this Paper we report the i, K, and 3.6 micron identifications of the 2273 X-ray point sources detected in the new Cycle 14 observations. We use the likelihood ratio technique to derive the association of optical/infrared...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1512.01105
3
3.0
Jun 29, 2018
06/18
by
G. B. Lansbury; D. Stern; J. Aird; D. M. Alexander; C. Fuentes; F. A. Harrison; E. Treister; F. E. Bauer; J. A. Tomsick; M. Balokovic; A. Del Moro; P. Gandhi; M. Ajello; A. Annuar; D. R. Ballantyne; S. E. Boggs; N. Brandt; M. Brightman; C. J. Chen; F. E. Christensen; F. Civano; A. Comastri; W. W. Craig; K. Forster; B. W. Grefenstette; C. J. Hailey; R. Hickox; B. Jiang; H. Jun; M. Koss; S. Marchesi; A. D. Melo; J. R. Mullaney; G. Noirot; S. Schulze; D. J. Walton; L. Zappacosta; W. Zhang
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We present the first full catalog and science results for the NuSTAR serendipitous survey. The catalog incorporates data taken during the first 40 months of NuSTAR operation, which provide ~20Ms of effective exposure time over 331 fields, with an areal coverage of 13 sq deg, and 497 sources detected in total over the 3-24 keV energy range. There are 276 sources with spectroscopic redshifts and classifications, largely resulting from our extensive campaign of ground-based spectroscopic followup....
Topics: Astrophysics, High Energy Astrophysical Phenomena, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1612.06389
4
4.0
Jun 29, 2018
06/18
by
F. Civano; S. Marchesi; A. Comastri; M. C. Urry; M. Elvis; N. Cappelluti; S. Puccetti; M. Brusa; G. Zamorani; G. Hasinger; T. Aldcroft; D. M. Alexander; V. Allevato; H. Brunner; P. Capak; A. Finoguenov; F. Fiore; A. Fruscione; R. Gilli; K. Glotfelty; R. E. Griffiths; H. Hao; F. A. Harrison; K. Jahnke; J. Kartaltepe; A. Karim; S. M. LaMassa; G. Lanzuisi; T. Miyaji; P. Ranalli; M. Salvato; M. Sargent; N. J. Scoville; K. Schawinski; E. Schinnerer; J. Silverman; V. Smolcic; D. Stern; S. Toft; B....
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The COSMOS-Legacy survey is a 4.6 Ms Chandra program that has imaged 2.2 deg$^2$ of the COSMOS field with an effective exposure of $\simeq$160 ks over the central 1.5 deg$^2$ and of $\simeq$80 ks in the remaining area. The survey is the combination of 56 new observations, obtained as an X-ray Visionary Project, with the previous C-COSMOS survey. We describe the reduction and analysis of the new observations and the properties of 2273 point sources detected above a spurious probability of...
Topics: Astrophysics, Astrophysics of Galaxies
Source: http://arxiv.org/abs/1601.00941
