The spatial clustering of X-ray selected AGN in the XMM-COSMOS field

R. Gilli, G. Zamorani, T. Miyaji, J. Silverman, M. Brusa, V. Mainieri, N. Cappelluti, E. Daddi, C. Porciani, L. Pozzetti, F. Civano, A. Comastri, A. Finoguenov, F. Fiore, M. Salvato, C. Vignali, G. Hasinger, S. Lilly, Christopher D Impey, J. TrumpP. Capak, H. McCracken, N. Scoville, Y. Taniguchi, C. M. Carollo, T. Contini, J. P. Kneib, O. Le Fevre, A. Renzini, M. Scodeggio, S. Bardelli, M. Bolzonella, A. Bongiorno, K. Caputi, A. Cimatti, G. Coppa, O. Cucciati, S. De La Torre, L. De Ravel, P. Franzetti, B. Garilli, A. Iovino, P. Kampczyk, C. Knobel, K. Kovač, F. Lamareille, J. F. Le Borgne, V. Le Brun, C. Maier, M. Mignoli, R. Pellò, Y. Peng, E. Perez Montero, E. Ricciardelli, M. Tanaka, L. Tasca, L. Tresse, D. Vergani, E. Zucca, U. Abbas, D. Bottini, A. Cappi, P. Cassata, M. Fumana, L. Guzzo, A. Leauthaud, D. Maccagni, C. Marinoni, P. Memeo, B. Meneux, P. Oesch, R. Scaramella, J. Walcher

Research output: Contribution to journalArticle

78 Citations (Scopus)

Abstract

We study the spatial clustering of 538 X-ray selected AGN in the 2 deg 2 XMM-COSMOS field that are spectroscopically identified with I AB < 23 and span the redshift range z = 0.2-3.0. The median redshift and X-ray luminosity of the sample are z = 0.98 and L0.5-10 = 6.3 × 1043 erg s-1, respectively. A strong clustering signal is detected at ∼ 18σ level, which is the most significant measurement obtained to date for clustering of X-ray selected AGN. By fitting the projected correlation function w(rp) with, a power law on scales of rp = 0.3-40 h-1 Mpc, we derive a best-fit comoving con-elation length of r0 = 8.6 ± 0.5 h-1 Mpc and slope of γ = 1.88 ± 0.07 (Poissonian errors; bootstrap errors are about a factor of 2 larger). An excess signal is observed in the range rp ∼ 5-15 h-1 Mpc, which is due to a large-scale structure at z ∼ 0.36 containing about 40 AGN, a feature which is evident over many wavelengths in the COSMOS field. When removing the z ∼ 0.36 structure or computing w(rp) in a narrower range around the peak of the redshift distribution (e.g. z = 0.4-1.6), the correlation length decreases to r0 ∼ 5-6 h-1 Mpc, which is consistent with what is observed for bright optical QSOs at the same redshift. We investigate the clustering properties of obscured and unobscured AGN separately, adopting different definitions for the source obscuration. For the first time, we are able to provide a significant measurement for the spatial clustering of obscured AGN at z ∼ 1. Within the statistical uncertainties, we do not find evidence that AGN with broad optical lines (BLAGN) cluster differently from AGN without broad optical lines (non-BLAGN). Based on these results, which are limited by object statistics, however, obscured and unobscured AGN are consistent with inhabiting similar environments. The evolution of AGN clustering with redshift is also investigated. No significant difference is found between the clustering properties of XMM-COSMOS AGN at redshifts below or above z = 1. The con-elation length measured for XMM-COSMOS AGN at z ∼ 1 is similar to that of massive galaxies (stellar mass M* ≳ 3 × 1010 M ) at the same redshift. This suggests that AGN at z ∼ 1 are preferentially hosted by massive galaxies, as observed both in the local and in the distant (z ∼ 2) Universe. According to a simple clustering evolution scenario, we find that the relics of AGN are expected to have a correlation length as large as r0 ∼ 8 h-1 Mpc by z = 0, and hence to be hosted by local bright (L ∼ L*) ellipticals. We make use of dark matter halo catalogs from the Millennium simulation to determine the typical halo hosting moderately luminous z ∼ 1 AGN. We find that XMM-COSMOS AGN live in halos with masses M ≳ 2.5 × 1012 M h-1. By combining the number density of XMM-COSMOS AGN to that of the hosting dark matter halos we estimate the AGN duty cycle and lifetimes. We find lifetimes approximately of 1 Gyr for AGN at z ∼ 1, which are longer than those estimated for optically bright QSOs at the same redshift. These longer lifetimes mainly reflect the higher number density of AGN selected by X-ray samples.

Original languageEnglish (US)
Pages (from-to)33-48
Number of pages16
JournalAstronomy and Astrophysics
Volume494
Issue number1
DOIs
StatePublished - Jan 2009

Fingerprint

XMM-Newton telescope
halos
x rays
life (durability)
quasars
dark matter
galaxies
occultation
stellar mass
catalogs
erg
universe
luminosity
COSMOS
statistics
slopes
power law
cycles
wavelength
estimates

Keywords

  • Cosmology
  • Cosmology: observations
  • Galaxies: active
  • Large-scale structure of universe
  • X-rays: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Gilli, R., Zamorani, G., Miyaji, T., Silverman, J., Brusa, M., Mainieri, V., ... Walcher, J. (2009). The spatial clustering of X-ray selected AGN in the XMM-COSMOS field. Astronomy and Astrophysics, 494(1), 33-48. https://doi.org/10.1051/0004-6361:200810821

The spatial clustering of X-ray selected AGN in the XMM-COSMOS field. / Gilli, R.; Zamorani, G.; Miyaji, T.; Silverman, J.; Brusa, M.; Mainieri, V.; Cappelluti, N.; Daddi, E.; Porciani, C.; Pozzetti, L.; Civano, F.; Comastri, A.; Finoguenov, A.; Fiore, F.; Salvato, M.; Vignali, C.; Hasinger, G.; Lilly, S.; Impey, Christopher D; Trump, J.; Capak, P.; McCracken, H.; Scoville, N.; Taniguchi, Y.; Carollo, C. M.; Contini, T.; Kneib, J. P.; Le Fevre, O.; Renzini, A.; Scodeggio, M.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Caputi, K.; Cimatti, A.; Coppa, G.; Cucciati, O.; De La Torre, S.; De Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Knobel, C.; Kovač, K.; Lamareille, F.; Le Borgne, J. F.; Le Brun, V.; Maier, C.; Mignoli, M.; Pellò, R.; Peng, Y.; Perez Montero, E.; Ricciardelli, E.; Tanaka, M.; Tasca, L.; Tresse, L.; Vergani, D.; Zucca, E.; Abbas, U.; Bottini, D.; Cappi, A.; Cassata, P.; Fumana, M.; Guzzo, L.; Leauthaud, A.; Maccagni, D.; Marinoni, C.; Memeo, P.; Meneux, B.; Oesch, P.; Scaramella, R.; Walcher, J.

In: Astronomy and Astrophysics, Vol. 494, No. 1, 01.2009, p. 33-48.

Research output: Contribution to journalArticle

Gilli, R, Zamorani, G, Miyaji, T, Silverman, J, Brusa, M, Mainieri, V, Cappelluti, N, Daddi, E, Porciani, C, Pozzetti, L, Civano, F, Comastri, A, Finoguenov, A, Fiore, F, Salvato, M, Vignali, C, Hasinger, G, Lilly, S, Impey, CD, Trump, J, Capak, P, McCracken, H, Scoville, N, Taniguchi, Y, Carollo, CM, Contini, T, Kneib, JP, Le Fevre, O, Renzini, A, Scodeggio, M, Bardelli, S, Bolzonella, M, Bongiorno, A, Caputi, K, Cimatti, A, Coppa, G, Cucciati, O, De La Torre, S, De Ravel, L, Franzetti, P, Garilli, B, Iovino, A, Kampczyk, P, Knobel, C, Kovač, K, Lamareille, F, Le Borgne, JF, Le Brun, V, Maier, C, Mignoli, M, Pellò, R, Peng, Y, Perez Montero, E, Ricciardelli, E, Tanaka, M, Tasca, L, Tresse, L, Vergani, D, Zucca, E, Abbas, U, Bottini, D, Cappi, A, Cassata, P, Fumana, M, Guzzo, L, Leauthaud, A, Maccagni, D, Marinoni, C, Memeo, P, Meneux, B, Oesch, P, Scaramella, R & Walcher, J 2009, 'The spatial clustering of X-ray selected AGN in the XMM-COSMOS field', Astronomy and Astrophysics, vol. 494, no. 1, pp. 33-48. https://doi.org/10.1051/0004-6361:200810821
Gilli R, Zamorani G, Miyaji T, Silverman J, Brusa M, Mainieri V et al. The spatial clustering of X-ray selected AGN in the XMM-COSMOS field. Astronomy and Astrophysics. 2009 Jan;494(1):33-48. https://doi.org/10.1051/0004-6361:200810821
Gilli, R. ; Zamorani, G. ; Miyaji, T. ; Silverman, J. ; Brusa, M. ; Mainieri, V. ; Cappelluti, N. ; Daddi, E. ; Porciani, C. ; Pozzetti, L. ; Civano, F. ; Comastri, A. ; Finoguenov, A. ; Fiore, F. ; Salvato, M. ; Vignali, C. ; Hasinger, G. ; Lilly, S. ; Impey, Christopher D ; Trump, J. ; Capak, P. ; McCracken, H. ; Scoville, N. ; Taniguchi, Y. ; Carollo, C. M. ; Contini, T. ; Kneib, J. P. ; Le Fevre, O. ; Renzini, A. ; Scodeggio, M. ; Bardelli, S. ; Bolzonella, M. ; Bongiorno, A. ; Caputi, K. ; Cimatti, A. ; Coppa, G. ; Cucciati, O. ; De La Torre, S. ; De Ravel, L. ; Franzetti, P. ; Garilli, B. ; Iovino, A. ; Kampczyk, P. ; Knobel, C. ; Kovač, K. ; Lamareille, F. ; Le Borgne, J. F. ; Le Brun, V. ; Maier, C. ; Mignoli, M. ; Pellò, R. ; Peng, Y. ; Perez Montero, E. ; Ricciardelli, E. ; Tanaka, M. ; Tasca, L. ; Tresse, L. ; Vergani, D. ; Zucca, E. ; Abbas, U. ; Bottini, D. ; Cappi, A. ; Cassata, P. ; Fumana, M. ; Guzzo, L. ; Leauthaud, A. ; Maccagni, D. ; Marinoni, C. ; Memeo, P. ; Meneux, B. ; Oesch, P. ; Scaramella, R. ; Walcher, J. / The spatial clustering of X-ray selected AGN in the XMM-COSMOS field. In: Astronomy and Astrophysics. 2009 ; Vol. 494, No. 1. pp. 33-48.
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title = "The spatial clustering of X-ray selected AGN in the XMM-COSMOS field",
abstract = "We study the spatial clustering of 538 X-ray selected AGN in the 2 deg 2 XMM-COSMOS field that are spectroscopically identified with I AB < 23 and span the redshift range z = 0.2-3.0. The median redshift and X-ray luminosity of the sample are z = 0.98 and L0.5-10 = 6.3 × 1043 erg s-1, respectively. A strong clustering signal is detected at ∼ 18σ level, which is the most significant measurement obtained to date for clustering of X-ray selected AGN. By fitting the projected correlation function w(rp) with, a power law on scales of rp = 0.3-40 h-1 Mpc, we derive a best-fit comoving con-elation length of r0 = 8.6 ± 0.5 h-1 Mpc and slope of γ = 1.88 ± 0.07 (Poissonian errors; bootstrap errors are about a factor of 2 larger). An excess signal is observed in the range rp ∼ 5-15 h-1 Mpc, which is due to a large-scale structure at z ∼ 0.36 containing about 40 AGN, a feature which is evident over many wavelengths in the COSMOS field. When removing the z ∼ 0.36 structure or computing w(rp) in a narrower range around the peak of the redshift distribution (e.g. z = 0.4-1.6), the correlation length decreases to r0 ∼ 5-6 h-1 Mpc, which is consistent with what is observed for bright optical QSOs at the same redshift. We investigate the clustering properties of obscured and unobscured AGN separately, adopting different definitions for the source obscuration. For the first time, we are able to provide a significant measurement for the spatial clustering of obscured AGN at z ∼ 1. Within the statistical uncertainties, we do not find evidence that AGN with broad optical lines (BLAGN) cluster differently from AGN without broad optical lines (non-BLAGN). Based on these results, which are limited by object statistics, however, obscured and unobscured AGN are consistent with inhabiting similar environments. The evolution of AGN clustering with redshift is also investigated. No significant difference is found between the clustering properties of XMM-COSMOS AGN at redshifts below or above z = 1. The con-elation length measured for XMM-COSMOS AGN at z ∼ 1 is similar to that of massive galaxies (stellar mass M* ≳ 3 × 1010 M ⊙) at the same redshift. This suggests that AGN at z ∼ 1 are preferentially hosted by massive galaxies, as observed both in the local and in the distant (z ∼ 2) Universe. According to a simple clustering evolution scenario, we find that the relics of AGN are expected to have a correlation length as large as r0 ∼ 8 h-1 Mpc by z = 0, and hence to be hosted by local bright (L ∼ L*) ellipticals. We make use of dark matter halo catalogs from the Millennium simulation to determine the typical halo hosting moderately luminous z ∼ 1 AGN. We find that XMM-COSMOS AGN live in halos with masses M ≳ 2.5 × 1012 M⊙ h-1. By combining the number density of XMM-COSMOS AGN to that of the hosting dark matter halos we estimate the AGN duty cycle and lifetimes. We find lifetimes approximately of 1 Gyr for AGN at z ∼ 1, which are longer than those estimated for optically bright QSOs at the same redshift. These longer lifetimes mainly reflect the higher number density of AGN selected by X-ray samples.",
keywords = "Cosmology, Cosmology: observations, Galaxies: active, Large-scale structure of universe, X-rays: galaxies",
author = "R. Gilli and G. Zamorani and T. Miyaji and J. Silverman and M. Brusa and V. Mainieri and N. Cappelluti and E. Daddi and C. Porciani and L. Pozzetti and F. Civano and A. Comastri and A. Finoguenov and F. Fiore and M. Salvato and C. Vignali and G. Hasinger and S. Lilly and Impey, {Christopher D} and J. Trump and P. Capak and H. McCracken and N. Scoville and Y. Taniguchi and Carollo, {C. M.} and T. Contini and Kneib, {J. P.} and {Le Fevre}, O. and A. Renzini and M. Scodeggio and S. Bardelli and M. Bolzonella and A. Bongiorno and K. Caputi and A. Cimatti and G. Coppa and O. Cucciati and {De La Torre}, S. and {De Ravel}, L. and P. Franzetti and B. Garilli and A. Iovino and P. Kampczyk and C. Knobel and K. Kovač and F. Lamareille and {Le Borgne}, {J. F.} and {Le Brun}, V. and C. Maier and M. Mignoli and R. Pell{\`o} and Y. Peng and {Perez Montero}, E. and E. Ricciardelli and M. Tanaka and L. Tasca and L. Tresse and D. Vergani and E. Zucca and U. Abbas and D. Bottini and A. Cappi and P. Cassata and M. Fumana and L. Guzzo and A. Leauthaud and D. Maccagni and C. Marinoni and P. Memeo and B. Meneux and P. Oesch and R. Scaramella and J. Walcher",
year = "2009",
month = "1",
doi = "10.1051/0004-6361:200810821",
language = "English (US)",
volume = "494",
pages = "33--48",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
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TY - JOUR

T1 - The spatial clustering of X-ray selected AGN in the XMM-COSMOS field

AU - Gilli, R.

AU - Zamorani, G.

AU - Miyaji, T.

AU - Silverman, J.

AU - Brusa, M.

AU - Mainieri, V.

AU - Cappelluti, N.

AU - Daddi, E.

AU - Porciani, C.

AU - Pozzetti, L.

AU - Civano, F.

AU - Comastri, A.

AU - Finoguenov, A.

AU - Fiore, F.

AU - Salvato, M.

AU - Vignali, C.

AU - Hasinger, G.

AU - Lilly, S.

AU - Impey, Christopher D

AU - Trump, J.

AU - Capak, P.

AU - McCracken, H.

AU - Scoville, N.

AU - Taniguchi, Y.

AU - Carollo, C. M.

AU - Contini, T.

AU - Kneib, J. P.

AU - Le Fevre, O.

AU - Renzini, A.

AU - Scodeggio, M.

AU - Bardelli, S.

AU - Bolzonella, M.

AU - Bongiorno, A.

AU - Caputi, K.

AU - Cimatti, A.

AU - Coppa, G.

AU - Cucciati, O.

AU - De La Torre, S.

AU - De Ravel, L.

AU - Franzetti, P.

AU - Garilli, B.

AU - Iovino, A.

AU - Kampczyk, P.

AU - Knobel, C.

AU - Kovač, K.

AU - Lamareille, F.

AU - Le Borgne, J. F.

AU - Le Brun, V.

AU - Maier, C.

AU - Mignoli, M.

AU - Pellò, R.

AU - Peng, Y.

AU - Perez Montero, E.

AU - Ricciardelli, E.

AU - Tanaka, M.

AU - Tasca, L.

AU - Tresse, L.

AU - Vergani, D.

AU - Zucca, E.

AU - Abbas, U.

AU - Bottini, D.

AU - Cappi, A.

AU - Cassata, P.

AU - Fumana, M.

AU - Guzzo, L.

AU - Leauthaud, A.

AU - Maccagni, D.

AU - Marinoni, C.

AU - Memeo, P.

AU - Meneux, B.

AU - Oesch, P.

AU - Scaramella, R.

AU - Walcher, J.

PY - 2009/1

Y1 - 2009/1

N2 - We study the spatial clustering of 538 X-ray selected AGN in the 2 deg 2 XMM-COSMOS field that are spectroscopically identified with I AB < 23 and span the redshift range z = 0.2-3.0. The median redshift and X-ray luminosity of the sample are z = 0.98 and L0.5-10 = 6.3 × 1043 erg s-1, respectively. A strong clustering signal is detected at ∼ 18σ level, which is the most significant measurement obtained to date for clustering of X-ray selected AGN. By fitting the projected correlation function w(rp) with, a power law on scales of rp = 0.3-40 h-1 Mpc, we derive a best-fit comoving con-elation length of r0 = 8.6 ± 0.5 h-1 Mpc and slope of γ = 1.88 ± 0.07 (Poissonian errors; bootstrap errors are about a factor of 2 larger). An excess signal is observed in the range rp ∼ 5-15 h-1 Mpc, which is due to a large-scale structure at z ∼ 0.36 containing about 40 AGN, a feature which is evident over many wavelengths in the COSMOS field. When removing the z ∼ 0.36 structure or computing w(rp) in a narrower range around the peak of the redshift distribution (e.g. z = 0.4-1.6), the correlation length decreases to r0 ∼ 5-6 h-1 Mpc, which is consistent with what is observed for bright optical QSOs at the same redshift. We investigate the clustering properties of obscured and unobscured AGN separately, adopting different definitions for the source obscuration. For the first time, we are able to provide a significant measurement for the spatial clustering of obscured AGN at z ∼ 1. Within the statistical uncertainties, we do not find evidence that AGN with broad optical lines (BLAGN) cluster differently from AGN without broad optical lines (non-BLAGN). Based on these results, which are limited by object statistics, however, obscured and unobscured AGN are consistent with inhabiting similar environments. The evolution of AGN clustering with redshift is also investigated. No significant difference is found between the clustering properties of XMM-COSMOS AGN at redshifts below or above z = 1. The con-elation length measured for XMM-COSMOS AGN at z ∼ 1 is similar to that of massive galaxies (stellar mass M* ≳ 3 × 1010 M ⊙) at the same redshift. This suggests that AGN at z ∼ 1 are preferentially hosted by massive galaxies, as observed both in the local and in the distant (z ∼ 2) Universe. According to a simple clustering evolution scenario, we find that the relics of AGN are expected to have a correlation length as large as r0 ∼ 8 h-1 Mpc by z = 0, and hence to be hosted by local bright (L ∼ L*) ellipticals. We make use of dark matter halo catalogs from the Millennium simulation to determine the typical halo hosting moderately luminous z ∼ 1 AGN. We find that XMM-COSMOS AGN live in halos with masses M ≳ 2.5 × 1012 M⊙ h-1. By combining the number density of XMM-COSMOS AGN to that of the hosting dark matter halos we estimate the AGN duty cycle and lifetimes. We find lifetimes approximately of 1 Gyr for AGN at z ∼ 1, which are longer than those estimated for optically bright QSOs at the same redshift. These longer lifetimes mainly reflect the higher number density of AGN selected by X-ray samples.

AB - We study the spatial clustering of 538 X-ray selected AGN in the 2 deg 2 XMM-COSMOS field that are spectroscopically identified with I AB < 23 and span the redshift range z = 0.2-3.0. The median redshift and X-ray luminosity of the sample are z = 0.98 and L0.5-10 = 6.3 × 1043 erg s-1, respectively. A strong clustering signal is detected at ∼ 18σ level, which is the most significant measurement obtained to date for clustering of X-ray selected AGN. By fitting the projected correlation function w(rp) with, a power law on scales of rp = 0.3-40 h-1 Mpc, we derive a best-fit comoving con-elation length of r0 = 8.6 ± 0.5 h-1 Mpc and slope of γ = 1.88 ± 0.07 (Poissonian errors; bootstrap errors are about a factor of 2 larger). An excess signal is observed in the range rp ∼ 5-15 h-1 Mpc, which is due to a large-scale structure at z ∼ 0.36 containing about 40 AGN, a feature which is evident over many wavelengths in the COSMOS field. When removing the z ∼ 0.36 structure or computing w(rp) in a narrower range around the peak of the redshift distribution (e.g. z = 0.4-1.6), the correlation length decreases to r0 ∼ 5-6 h-1 Mpc, which is consistent with what is observed for bright optical QSOs at the same redshift. We investigate the clustering properties of obscured and unobscured AGN separately, adopting different definitions for the source obscuration. For the first time, we are able to provide a significant measurement for the spatial clustering of obscured AGN at z ∼ 1. Within the statistical uncertainties, we do not find evidence that AGN with broad optical lines (BLAGN) cluster differently from AGN without broad optical lines (non-BLAGN). Based on these results, which are limited by object statistics, however, obscured and unobscured AGN are consistent with inhabiting similar environments. The evolution of AGN clustering with redshift is also investigated. No significant difference is found between the clustering properties of XMM-COSMOS AGN at redshifts below or above z = 1. The con-elation length measured for XMM-COSMOS AGN at z ∼ 1 is similar to that of massive galaxies (stellar mass M* ≳ 3 × 1010 M ⊙) at the same redshift. This suggests that AGN at z ∼ 1 are preferentially hosted by massive galaxies, as observed both in the local and in the distant (z ∼ 2) Universe. According to a simple clustering evolution scenario, we find that the relics of AGN are expected to have a correlation length as large as r0 ∼ 8 h-1 Mpc by z = 0, and hence to be hosted by local bright (L ∼ L*) ellipticals. We make use of dark matter halo catalogs from the Millennium simulation to determine the typical halo hosting moderately luminous z ∼ 1 AGN. We find that XMM-COSMOS AGN live in halos with masses M ≳ 2.5 × 1012 M⊙ h-1. By combining the number density of XMM-COSMOS AGN to that of the hosting dark matter halos we estimate the AGN duty cycle and lifetimes. We find lifetimes approximately of 1 Gyr for AGN at z ∼ 1, which are longer than those estimated for optically bright QSOs at the same redshift. These longer lifetimes mainly reflect the higher number density of AGN selected by X-ray samples.

KW - Cosmology

KW - Cosmology: observations

KW - Galaxies: active

KW - Large-scale structure of universe

KW - X-rays: galaxies

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