Black hole growth and starburst activity at<i>z</i>= 0.6–4 in the Chandra Deep Field South

Brusa, M.; Fiore, F.; Santini, P.; Grazian, A.; Comastri, A.; Zamorani, G.; Hasinger, G.; Merloni, A.; Civano, F.; Fontana, A.; Mainieri, V.

doi:10.1051/0004-6361/200912261

Cited by 103 publications

(142 citation statements)

References 94 publications

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“…Bands are plotted rather than curves to emphasize the rather large uncertainties, especially at highz (see next section). The same figure shows the previous evaluations of Brusa et al (2009b). These are consistent with the present estimates within their rather large error bars.…”

Section: Agn Luminosity Function and Duty Cycle Evolutionsupporting

confidence: 92%

“…Similar trends have been found by Kauffmann et al (2003), Best et al (2005), Bundy et al (2008), Yamada et al (2009), andBrusa et al (2009b) for optically-selected, radio-selected, and X-ray selected AGN. At each given stellar mass, the duty cycle increases with redshift up to z = 4-5, which is consistent with the results of Marconi et al (2004); Brusa et al (2009b), and Shankar et al (2009a). There are 22 galaxies in the GOODS-ERS catalog with z > 3 and stellar mass higher than 10 11.25 M , 7 of which are X-ray sources in Table 1, thus confirming an AGN duty cycle > ∼ 30% at z > 3 for these massive galaxies.…”

Section: Agn Luminosity Function and Duty Cycle Evolutionsupporting

confidence: 83%

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Faint high-redshift AGN in theChandradeep field south: the evolution of the AGN luminosity function and black hole demography

Fiore

Puccetti²,

Grazian

et al. 2011

A&A

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156

172

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Context. We present detection and analysis of faint X-ray sources in the Chandra deep field south (CDFS) using the 4 Ms Chandra observation. Aims. We place constraints on active galactic nuclei (AGN) luminosity functions at z = 3-7, its cosmological evolution, and highredshift black hole and AGN demography. Methods. We use a new detection algorithm, using the entire three-dimensional data-cube (position and energy), and searching for X-ray counts at the position of high-z galaxies in the GOODS-South survey.Results. This optimized technique results in the identification of 54 AGN at z > 3, 29 of which are new detections. Applying stringent completeness criteria, we derive AGN luminosity functions in the redshift bins 3-4, 4-5, and >5.8 and for 42.75 < log L(2-10 keV) < 44.5. We combine this data with the luminous AGN luminosity functions from optical surveys and find that the evolution of the high-z, wide luminosity range luminosity function can be modeled by pure luminosity evolution with L * decreasing from 6.6 × 10 44 erg/s at z = 3 to L * = 2 × 10 44 erg/s at z = 6. We compare the high-z luminosity function with the predictions of theoretical models using galaxy interactions as AGN triggering mechanism. We find that these models are broadly able to reproduce the high-z AGN luminosity functions. Closer agreement is found when we assume a minimum dark matter halo mass for black hole formation and growth. We compare our AGN luminosity functions with galaxy mass functions to derive the high-z AGN duty cycle, using observed Eddington ratio distributions to derive black hole masses. We find that the duty cycle increases with galaxy stellar mass and redshift by a factor of 10-30 from z = 0.25 to z = 4-5. We also report the detection of a large fraction of highly obscured, Compton thick AGN at z > 3 (18 +17 −10 %). Their optical counterparts do not show any reddening and we thus conclude that the size of the X-ray absorber is likely smaller than the dust sublimation radius. We finally report the discovery of a highly star-forming galaxy at z = 3.47, arguing that its X-ray luminosity is likely dominated by stellar sources. If confirmed, this would be one of the farthest objects in which stellar sources have been detected in X-rays.

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Section: Agn Luminosity Function and Duty Cycle Evolutionsupporting

confidence: 92%

Section: Agn Luminosity Function and Duty Cycle Evolutionsupporting

confidence: 83%

Faint high-redshift AGN in theChandradeep field south: the evolution of the AGN luminosity function and black hole demography

Fiore

Puccetti²,

Grazian

et al. 2011

A&A

Self Cite

156

172

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“…Interestingly most of our sources fall in the star-forming galaxy regime, although the vast majority are bona-fide AGN on the basis of their high X-ray luminosity and high L X /L 6 μm ratio. Brusa et al (2009b) reach similar conclusions by examining the Spitzer colours of obscured AGN in the 1Ms CDFS observation.…”

Section: Irac Colour-colour Diagramsupporting

confidence: 66%

X-ray detected infrared excess AGN in theChandradeep fields: a moderate fraction ofCompton-thick sources

Georgantopoulos

Rovilos

Xilouris

et al. 2010

A&A

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We examine the properties of the X-ray-detected infrared excess AGN or dust obscured galaxies (DOGs) in the Chandra deep fields (CDFs). We find 26 X-ray-detected sources that obey the 24 μm to R-band flux ratio criterion f 24 / f R > 1000. These are at a median redshift of 2.3, while their IR luminosities are above 10 12 L . Their X-ray luminosities are all above a few times 10 42 erg s −1 in the 2-10 keV band, which unambiguously argues that they host AGN. Nevertheless, their IR spectral energy distributions are split between AGN (Mrk231) and star-forming templates (Arp220). Our primary goal is to examine their individual X-ray spectra in order to assess whether this X-ray-detected DOG population contains heavily obscured or even Compton-thick sources. The X-ray spectroscopy reveals a mixed bag of objects. We find that four out of the 12 sources with adequate photon statistics and hence reliable X-ray spectra show evidence for a hard X-ray spectral index with Γ ∼ 1 or harder, which is consistent with a Compton-thick spectrum. In total 12 out of the 26 DOGs show evidence for flat spectral indices. However, owing to the limited photon statistics we cannot distinguish whether they are flat because they are reflection-dominated or because they show moderate amounts of absorption. Seven DOGs show relatively steep spectra Γ > 1.4, indicative of low column densities. All the above suggests a fraction of Compton-thick sources that does not exceed 50%. The average X-ray spectrum of all 26 DOGs is hard (Γ ∼ 1.1) or even harder (Γ ∼ 0.6) when we exclude the brightest sources. These spectral indices agree with the stacked spectrum of X-ray-undetected sources (Γ ≈ 0.8 in the CDFN). This could suggest (but not necessarily prove) that X-ray undetected DOGs, in a similar way as the X-ray-detected ones presented here, are hosting a moderate fraction of Compton-thick sources.

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“…Note that 133 GALs out of the total of 196 in total were not observed in the hard band. Stern et al 2005;Lacy et al 2007;Brusa et al 2009Brusa et al , 2010. In total 1467 (51%) AGN/QSOs and 117 GALs (60%) were observed in all 4 IRAC bands.…”

Section: The Hardness Ratiomentioning

confidence: 97%

Classification and environmental properties of X-ray selected point-like sources in the XMM-LSS field

Мelnyk

Plionis

Elyiv

et al. 2013

A&A

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Context. The XMM-Large Scale Structure survey, covering an area of 11.1 sq. deg., contains more than 6000 X-ray point-like sources detected with the XMM-Newton to a flux of 3 × 10 −15 erg s −1 cm −2 in the [0.5−2] keV band. The vast majority of these sources have optical (CFHTLS), infrared (SWIRE IRAC and MIPS), near-infrared (UKIDSS), and/or ultraviolet (GALEX) counterparts. Aims. We wish to investigate the environmental properties of the different types of the XMM-LSS X-ray sources by defining their environment using the i -band CFHTLS W1 catalog of optical galaxies to a magnitude limit of 23.5 mag. Methods. We have classified 4435 X-ray selected sources on the basis of their spectra, SEDs, and X-ray luminosity, and estimated their photometric redshifts, which have a 4−11 band photometry with an accuracy of σ z/(1+zsp) = 0.076 with 22.6% outliers for i < 26 mag. We estimated the local overdensities of 777 X-ray sources that have spectro-z or photo-z calculated by using more than seven bands (accuracy of σ z/(1+zsp) = 0.061 with 13.8% outliers) within the volume-limited region defined by 0.1 ≤ z ≤ 0.85 and −23.5 < M i < −20. Results. Although X-ray sources may be found in variety of environments, a high fraction ( > ∼ 55−60%), as verified by comparing with the random expectations, reside in overdense regions. The galaxy overdensities within which X-ray sources reside show a positive recent redshift evolution (at least for the range studied; z < ∼ 0.85). We also find that X-ray selected galaxies, when compared to AGN, inhabit significantly higher galaxy overdensities, although their spatial extent appear to be smaller than that of AGN. Hard AGN (HR ≥ −0.2) are located in more overdense regions than soft AGN (HR < −0.2), which is clearly seen in both redshift ranges, although it appears to be stronger in the higher redshift range (0.55 < z < 0.85). Furthermore, the galaxy overdensities (with δ > ∼ 1.5) within which soft AGN are embedded appear to evolve more rapidly compared to the corresponding overdensities around hard AGN.

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Black hole growth and starburst activity atz= 0.6–4 in the Chandra Deep Field South

Cited by 103 publications

References 94 publications

Faint high-redshift AGN in theChandradeep field south: the evolution of the AGN luminosity function and black hole demography

Faint high-redshift AGN in theChandradeep field south: the evolution of the AGN luminosity function and black hole demography

X-ray detected infrared excess AGN in theChandradeep fields: a moderate fraction ofCompton-thick sources

Classification and environmental properties of X-ray selected point-like sources in the XMM-LSS field

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