J/ApJ/954/174 JCMT-SCUBA2 High rEdshift bRight quasaR surveY. II. (Li+, 2023)
SCUBA-2 High rEdshift bRight quasaR surveY (SHERRY).
II. The environment of z∼6 quasars at submillimeter band.
Li Q., Wang R., Fan X., Wu X.-B., Jiang L., Banados E., Venemans B.,
Shao Y., Li J., Wagg J., Decarli R., Mazzucchelli C., Omont A.,
Bertoldi F., Johnson S., Conselice C.J., Zhang C.
<Astrophys. J., 954, 174 (2023)>
=2023ApJ...954..174L 2023ApJ...954..174L
ADC_Keywords: QSOs; Photometry, millimetric/submm; Galaxies;
Keywords: Quasars ; Submillimeter astronomy ; Active galaxies
Abstract:
The formation of the first supermassive black holes is expected to
have occurred in some most pronounced matter and galaxy overdensities
in the early universe. We have conducted a submillimeter wavelength
continuum survey of 54 z∼6 quasars using the Submillimeter Common-User
Bolometre Array-2 on the James Clerk Maxwell Telescope to study the
environments around z∼6 quasars. We identified 170 submillimeter
galaxies (SMGs) with above 3.5σ detections in 450 or 850µm
maps. Their far-IR luminosities are (2.2-6.4)x1012L☉, and
their star formation rates are ∼400-1200M☉/yr. We also
calculated the SMGs' differential and cumulative number counts in a
combined area of ∼620arcmin2. To a 4σ detection (at ∼5.5mJy),
SMGs' overdensity is 0.68-0.19+0.21(±0.19), exceeding the
blank-field source counts by a factor of 1.68. We find that 13/54
quasars show overdensities (at ∼5.5mJy) of δSMG∼1.5-5.4. The
combined area of these 13 quasars exceeds the blank-field counts with
the overdensity to 5.5mJy of δSMG∼2.46-0.55+0.64(±0.25)
in the regions of ∼150arcmin2. However, the excess is insignificant
on the bright end (e.g., 7.5mJy). We also compare results with
previous environmental studies of Lyα emitters and Lyman break
galaxies on a similar scale. Our survey presents the first systematic
study of the environment of quasars at z∼6. The newly discovered SMGs
provide essential candidates for follow-up spectroscopic observations
to test whether they reside in the same large-scale structures as the
quasars and search for protoclusters at an early epoch.
Description:
We observed 54 quasars at 5.7<z<7.1, which have rest-frame 1450Å
absolute magnitudes of M1450≤-25.4. The observations were carried
out with the SCUBA-2 camera on the JCMT in Hawaii from 2015 August to
2018 January (Program ID: M15BI055, M16AP013, M17AP062, M17BP034). We
used "the constant velocity Daisy scan" observation mode ("CV Daisy"
mode) with a field of view of 15' in diameter.
SCUBA-2 observes two bands, 450 and 850um, simultaneously. The main
beam sizes of SCUBA-2 are 7.9" at 450um and 14.9" at 850um, with a
spatial resolution of 4" and 2"/pixel, respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 102 190 The catalog of submillimeter galaxies (SMGs) and
SMG candidates in the quasar nearby fields at z∼6
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See also:
J/MNRAS/384/1611 : Submm observations in gravitational lenses (Knudsen+, 2008)
J/ApJ/704/548 : Phot. properties of galaxies at z=4-6 (Overzier+, 2009)
J/MNRAS/416/2041 : Hα emitters at z=2.23 (Matsuda+, 2011)
J/MNRAS/436/1919 : SCUBA observations of COSMOS galaxies (Casey+, 2013)
J/ApJ/768/91 : ALMA observations of LESS submm galaxies (Hodge+, 2013)
J/ApJS/227/11 : PS1 z>5.6 quasars follow-up (Banados+, 2016)
J/MNRAS/465/1789 : SCUBA-2 Cosmology Legacy Survey (Geach+, 2017)
J/ApJ/863/92 : LAE at z∼5.7 in the field of QSO J0148+0600 (Becker+, 2018)
J/ApJ/903/4 : Lyα Emitters at Redshift z∼5.7 with M2FS (Ning+, 2020)
J/ApJ/923/262 : NIR spectroscopic obs. of z>6.5 quasars (Yang+, 2021)
J/ApJS/265/29 : PS1 z>5.6 QSO Survey. II. 55 QSOs follow-up (Banados+, 2023)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- SMG SMG identifier (1)
17- 18 I2 h RAh Hour of Right Ascension (J2000)
20- 21 I2 min RAm Minute of Right Ascension (J2000)
23- 26 F4.1 s RAs Second of Right Ascension (J2000)
28 A1 --- DE- Sign of the Declination (J2000)
29- 30 I2 deg DEd Degree of Declination (J2000)
32- 33 I2 arcmin DEm Arcminute of Declination (J2000)
35- 38 F4.1 arcsec DEs Arcsecond of Declination (J2000)
40- 44 F5.2 mJy S850 [3.5/17] SMG peak flux density, Sν at 850um
46- 49 F4.2 mJy e_S850 [0.9/1.5] Uncertainty in S850
51- 55 F5.2 --- SN850 [3/15.4] Signal-to-noise ratio, S850
57- 61 F5.2 mJy S850d [2.6/17] Deboosted flux density, Sν at 850um
63- 66 F4.2 mJy e_S850d [0.9/2.2] Uncertainty in S850d
68- 73 F6.2 mJy S450 [25/114]? SMG peak flux density, Sν at 450um
75- 79 F5.2 mJy e_S450 [7.7/36.2]? Uncertainty in S450
81- 84 F4.2 --- SN450 [3/4.2]? Signal-to-noise ratio, S450
86- 90 F5.2 mJy S450d [20/94]? Deboosted flux density, Sν at 450um
92- 96 F5.2 mJy e_S450d [7.2/33.6]? Uncertainty in S450d
98- 102 F5.3 arcmin Offset [0/2.8] Angular distance between SMGs &
central quasar
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Note (1): SMG identifiers of the form -- ObjectShortName-SMG+index
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History:
From electronic version of the journal
References:
Li et al. Paper I. 2020ApJ...900...12L 2020ApJ...900...12L
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Oct-2025