J/ApJ/765/87 Chandra observations of the 2QZ Cluster 1004+00 (Lehmer+, 2013)
Concurrent supermassive black hole and galaxy growth: linking environment and
nuclear activity in z = 2.23 Hα emitters.
Lehmer B.D., Lucy A.B., Alexander D.M., Best P.N., Geach J.E.,
Harrison C.M., Hornschemeier A.E., Matsuda Y., Mullaney J.R., Smail I.,
Sobral D., Swinbank A.M.
<Astrophys. J., 765, 87 (2013)>
=2013ApJ...765...87L 2013ApJ...765...87L
ADC_Keywords: X-ray sources ; Galaxies, optical ; QSOs
Keywords: cosmology: observations; early universe; galaxies: active;
galaxies: clusters: general; surveys; X-rays: general
Abstract:
We present results from a ~100ks 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 15x15arcmin2 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 Hα-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 2-10keV luminosities of ~(8-60)x1043erg/s
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
~2 times over the field), and after excluding
optically-selected QSOs, we find that the AGN fraction is a factor of
~3.5+3.8-2.2 times higher than C-COSMOS HAEs in similar
environments. Using stacking analyses of the Chandra data and Herschel
SPIRE observations at 250µm, we respectively estimate mean SMBH
accretion rates ((dM/dt)BH) and star formation rates (SFRs) for the
2QZ Clus and C-COSMOS samples.
Description:
We obtained a ∼100ks Chandra exposure consisting of a single
16.9'x16.9' ACIS-I pointing (Chandra ObsID 13976; taken over the 2012
January 13 and 14; PI: B. D. Lehmer) centered on the 2QZ Clus region
surveyed by Matsuda et al. (2011, J/MNRAS/416/2041; see Figure 1). The
observation was centered on the aim point coordinates RA=10:03:43.3,
DE=+00:13:26.47 (J2000).
The Galactic column densities for 2QZ Clus and COSMOS are
3.0x1020/cm2 and 2.5x1020/cm2, respectively. All of the X-ray
fluxes and luminosities quoted throughout this paper have been
corrected for Galactic absorption.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 165 133 Chandra point-source catalog of the 2QZ Cluster field
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
VIII/95 : Herschel Multi-tiered Extragalactic Survey (Oliver+, 2012)
VII/265 : COSMOS Morphological Catalog (V1.1) (Tasca+ 2009)
VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004)
J/MNRAS/428/1128 : UDS/COSMOS HiZELS galaxies (Sobral+, 2013)
J/ApJS/201/30 : The Chandra COSMOS survey. III. (Civano+, 2012)
J/MNRAS/416/2041 : Hα emitters at z=2.23 (Matsuda+, 2011)
J/ApJ/720/368 : Color-magnitude relations of galaxies in CDFs (Xue+, 2010)
J/MNRAS/400/299 : Chandra deep protocluster survey (Lehmer+, 2009)
J/ApJS/184/158 : Chandra COSMOS survey I. (Elvis+, 2009)
J/ApJ/681/1163 : Late-type galaxies in Chandra deep fields (Lehmer+, 2008)
J/ApJ/666/806 : SED of Spitzer quasars (QUEST) (Netzer+, 2007)
J/ApJ/554/742 : Chandra Deep Survey of the HDF-N (Hornschemeier+, 2001)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/133] Source identification number
5- 6 I2 h RAh [10] Hour of Right Ascension (J2000)
8- 9 I2 min RAm [3/4] Minute of Right Ascension (J2000)
11- 14 F4.1 s RAs Second of Right Ascension (J2000)
16 A1 --- DE- [+] Sign of the Declination (J2000)
17- 18 I2 deg DEd [00] Degree of Declination (J2000)
20- 21 I2 arcmin DEm [3/23] Arcminute of Declination (J2000)
23- 26 F4.1 arcsec DEs Arcsecond of Declination (J2000)
28- 32 F5.1 ct Fcts [2.2/464] Net full 0.5-7keV band counts
34- 37 F4.1 ct E_Fcts [-1/24] Upper 1σ bound on Fcts (1)
39- 42 F4.1 ct e_Fcts [-1/23] Lower 1σ bound on Fcts (1)
44- 48 F5.1 ct Scts [1.9/307] Net soft 0.5-2keV band counts
50- 53 F4.1 ct E_Scts [-1/20] Upper 1σ bound on Scts (1)
55- 58 F4.1 ct e_Scts [-1/19] Lower 1σ bound on Scts (1)
60- 64 F5.1 ct Hcts [6.2/157] Net hard 2-7keV band counts
66- 69 F4.1 ct E_Hcts [-1/15] Upper 1σ bound on Hcts (1)
71- 74 F4.1 ct e_Hcts [-1/14] Lower 1σ bound on Hcts (1)
76- 79 F4.1 ks Fexp Full 0.5-7keV vignetting corrected exposure
81- 84 F4.1 ks Sexp Soft 0.5-2keV vignetting corrected exposure
86- 89 F4.1 ks Hexp Hard 2-7keV vignetting corrected exposure
91- 94 F4.1 10-4ct/s FCR [0.3/51] Full 0.5-7keV band count rate
96- 99 F4.1 10-4ct/s E_FCR [-1/7] Upper 1σ bound on FCR (1)
101-104 F4.1 10-4ct/s e_FCR [-1/5] Lower 1σ bound on FCR (1)
106-109 F4.1 10-4ct/s SCR [0.2/34] Soft 0.5-2keV band count rate
111-114 F4.1 10-4ct/s E_SCR [-1/6] Upper 1σ bound on SCR (1)
116-119 F4.1 10-4ct/s e_SCR [-1/4] Lower 1σ bound on SCR (1)
121-124 F4.1 10-4ct/s HCR [0.6/17] Hard 2-7keV band count rate
126-129 F4.1 10-4ct/s E_HCR [-1/2] Upper 1σ bound on HCR (1)
131-134 F4.1 10-4ct/s e_HCR [-1/5] Lower 1σ bound on HCR (1)
136-143 E8.2 mW/m2 Fflux Full 0.5-7keV band flux; erg/s/cm2
145-152 E8.2 mW/m2 Sflux Soft 0.5-2keV band flux; erg/s/cm2
154-161 E8.2 mW/m2 Hflux Hard 2-7keV band flux; erg/s/cm2
163-165 A3 --- n_Seq Note(s) on source (2)
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Note (1): A negative value indicates an upper limit, e.g. "-1.00".
Note (2): Flag as follows:
M = Manual photometry required due to image edge;
H = Coincident with z=2.23 HAE;
Q = Coincident with QSO.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 31-Oct-2014