CONCURRENT SUPERMASSIVE BLACK HOLE AND GALAXY GROWTH: LINKING ENVIRONMENT AND NUCLEAR ACTIVITY IN z = 2.23 H{alpha} EMITTERS

Journal Article · Sun Mar 10 04:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/765/2/87· OSTI ID:22127018

Lehmer, B. D.; Hornschemeier, A. E. ^[1]; Lucy, A. B. ^[2]; Alexander, D. M.; Harrison, C. M.; Mullaney, J. R.; Swinbank, A. M. ^[3]; Best, P. N. ^[4]; Geach, J. E. ^[5]; Matsuda, Y. ^[6]; Smail, Ian ^[7]; Sobral, D. ^[8]

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1. Department of Physics and Astronomy, Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States)
2. NASA Goddard Space Flight Centre, Code 662, Greenbelt, MD 20771 (United States)
3. Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
4. SUPA, Institute for Astronomy, Royal Observatory of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)
5. Department of Physics, McGill University, 3600 rue University, Montreal, Quebec H3A 2T8 (Canada)
6. Chile Observatory, National Astronomical Observatory of Japan, Tokyo 181-8588 (Japan)
7. Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom)
8. Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands)

We present results from a Almost-Equal-To 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 15 Multiplication-Sign 15 arcmin{sup 2} region. Narrow-band imaging in the near-IR (within the K band) revealed that the structure contains an additional overdensity of 22 z = 2.23 H{alpha}-emitting galaxies (HAEs), resulting in 23 unique z = 2.23 HAEs/QSOs (22 within the Chandra field of view). Our Chandra observations reveal that three HAEs in addition to the four QSOs harbor powerfully accreting supermassive black holes (SMBHs), with 2-10 keV luminosities of Almost-Equal-To (8-60) Multiplication-Sign 10{sup 43} erg s{sup -1} and X-ray spectral slopes consistent with unobscured active galactic nucleus (AGN). Using a large comparison sample of 210 z = 2.23 HAEs in the Chandra-COSMOS field (C-COSMOS), we find suggestive evidence that the AGN fraction increases with local HAE galaxy density. The 2QZ Clus HAEs reside in a moderately overdense environment (a factor of Almost-Equal-To 2 times over the field), and after excluding optically-selected QSOs, we find that the AGN fraction is a factor of Almost-Equal-To 3.5{sup +3.8}{sub -2.2} times higher than C-COSMOS HAEs in similar environments. Using stacking analyses of the Chandra data and Herschel SPIRE observations at 250 {mu}m, we respectively estimate mean SMBH accretion rates ( M-dot{sub BH}) and star formation rates (SFRs) for the 2QZ Clus and C-COSMOS samples. We find that the mean 2QZ Clus HAE stacked X-ray luminosity is QSO-like (L{sub 2-10{sub keV}} Almost-Equal-To [6-10] Multiplication-Sign 10{sup 43} erg s{sup -1}), and the implied M-dot{sub BH}/SFR Almost-Equal-To (1.6-3.2) Multiplication-Sign 10{sup -3} is broadly consistent with the local M{sub BH}/M{sub *} relation and z Almost-Equal-To 2 X-ray selected AGN. In contrast, the C-COSMOS HAEs are on average an order of magnitude less X-ray luminous and have M-dot{sub BH}/SFR Almost-Equal-To (0.2-0.4) Multiplication-Sign 10{sup -3}, somewhat lower than the local M{sub BH}/M{sub *} relation, but comparable to that found for z Almost-Equal-To 1-2 star-forming galaxies with similar mean X-ray luminosities. We estimate that a periodic QSO phase with duty cycle Almost-Equal-To 2%-8% would be sufficient to bring star-forming galaxies onto the local M{sub BH}/M{sub *} relation. This duty cycle is broadly consistent with the observed C-COSMOS HAE AGN fraction ( Almost-Equal-To 0.4%-2.3%) for powerful AGN with L{sub X} {approx}> 10{sup 44} erg s{sup -1}. Future observations of 2QZ Clus will be needed to identify key factors responsible for driving the mutual growth of the SMBHs and galaxies.

• OSTI ID: 22127018
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 765; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
BLACK HOLES
COMPARATIVE EVALUATIONS
COSMOLOGY
GALAXIES
GALAXY CLUSTERS
GALAXY NUCLEI
KEV RANGE
LUMINOSITY
NEAR INFRARED RADIATION
PERIODICITY
STAR EVOLUTION
STARS
X RADIATION