J/A+A/676/A51 SCUBA-2 obs of high-z quasars (Arrigoni Battaia+, 2023)
JCMT/SCUBA-2 uncovers excess of 850 µm counts on megaparsec scales around
high-redshift quasars. Characterisation of the overdensities and their alignment
with the quasars' Lyman-alpha nebulae.
Arrigoni Battaia F., Obreja A., Chen C.-C., Nowotka M., Fumagalli M.,
Prochaska J.X., Yang Y., Cai Z., Munoz-Elgueta N., Fossati M.
<Astron. Astrophys. 676, A51 (2023)>
=2023A&A...676A..51A 2023A&A...676A..51A (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Millimetric/submm sources ; QSOs
Keywords: submillimeter: galaxies - galaxies: high-redshift - galaxies: halos -
quasars: general - galaxies: evolution -
large-scale structure of Universe
Abstract:
We conducted a systematic survey of the environment of high-redshift
quasars at submillimeter wavelengths to unveil and characterize the
surrounding distribution of dusty submillimeter galaxies (SMGs). We
took sensitive observations with the SCUBA-2 instrument on the James
Clerk Maxwell Telescope for 3 Enormous Lyman-Alpha Nebulae (ELANe) and
17 quasar fields in the redshift range 2<z<4.2 selected from recent
Lyman-α (Lyα) surveys. These observations uncovered 523
and 102 sources at 850µm and 450µm, respectively, with
signal-to-noise S/N>4 or detected in both bands at S/N>3. We run
self-consistent Monte-Carlo simulations to construct 850µm number
counts and unveil an excess of sources in 75% of the targeted fields.
Overall, regions around ELANe and quasars are overabundant with
respect to blank fields by a factor of (weighted averages) 3.4±0.4
and 2.5±0.2, respectively. Therefore, the excess of submillimeter
sources is likely part of the Mpc-scale environment around these
systems. By combining all fields and repeating the counts analysis in
radial apertures, we find (at high significance ≳5σ) a
decrease of the overdensity factor from >3 within ∼2cMpc to ∼2 in the
annulus at the edge of the surveyed field (∼10cMpc), suggesting that
the physical extent of the overdensities is larger than our maps. We
computed preferred directions for the overdensities of SMGs from the
positions of the sources, and used them to orient and create stacked
maps of source densities for the quasars' environment. This stacking
unveils an elongated structure reminiscent of a large-scale filament
with a scale width of ~=3cMpc. Finally, the directions of the
overdensities are roughly aligned with the major axis of the Lyα
nebulae, suggesting that the latter trace, on hundreds of kpc, the
central regions of the projected large-scale structure described by
the SMGs on Mpc scales. Confirming member associations of the SMGs is
required to further characterize their spatial and kinematic
distribution around ELANe and quasars.
Description:
The dataset for the 20 quasar fields studied in this work were
acquired with the Submillimetre Common-User Bolometer Array 2
(SCUBA-2) on the James Clerk Maxwell Telescope (JCMT) during flexible
observing from 2017 September till 2021 July 17 (programs IDs:
M17BP024, M18AP054, M18BP062, M19BP048, M21AP041, M21AP046) under good
weather conditions (τ225GHz≤0.07). For each target, the
observations covered a field-of-view of ~=13.7' in diameter using a
DAISY scanning pattern centered on each quasar position. Each field
was scheduled with cycles (scans) of about 30 minutes, resulting
in ∼7 hours (∼14 scans) for the targets Jackpot, MAMMOTH-1, and
Fabulous; ∼6 hours (∼12 scans) for the target SDSSJ1209+1138;
∼3.5-4.8 hours (∼7-10 scans) for targets SDSSJ1557+1540,
SDSSJ1342+1702, Q-0115-30, J024401-013403; and ∼3 hours (∼6 scans) for
the remaining targets. Precise details of the observations can be
found in Table 1 of the paper. SCUBA-2 acquires simultaneously data at
850 and 450µm.
For each field we provide the source catalogs at 850 and 450µm.
These catalogs include ≥4σ detections and those which are at
>3σ in both bands. Entries with no value have -99 or -99.9
For the three fields Jackpot, MAMMOTH-1, and Fabulous we kept the
naming from Nowotka et al. (2022A&A...658A..77N 2022A&A...658A..77N) for the sources in
common.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tab_450u.dat 139 101 SCUBA-2 450um detected sources within the
assumed effective area in 20 quasar fields
tab_850u.dat 136 525 SCUBA-2 850um detected sources within the
assumed effective area in 20 quasar fields
list.dat 126 40 List of fits files
fits/* . 40 Individual fits files
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Byte-by-byte Description of file: tab_450u.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Field Table number (F1-F40 even numbers) (1)
5- 27 A23 --- Name450 Source name at 450um
28- 29 I2 h RAh Right ascension (J2000)
31- 32 I2 min RAm Right ascension (J2000)
34- 37 F4.1 s RAs Right ascension (J2000)
40 A1 --- DE- Declination sign (J2000)
41- 42 I2 deg DEd Declination (J2000)
44- 45 I2 arcmin DEm Declination (J2000)
47- 48 I2 arcsec DEs Declination (J2000)
53- 55 F3.1 --- S/N Signal-to-noise ratio
59- 61 I3 mJy F450 Flux density at 450um
63- 64 I2 mJy e_F450 Error on flux density at 450um
68- 69 I2 mJy F450D Deboosted flux density at 450um
71- 72 I2 mJy e_F450D Error on Deboosted flux density at 450um
77- 79 F3.1 arcsec ePos Error on position
83-106 A24 --- Name850 Counterpart name at 850um
107-110 F4.1 --- S/N850 Signal-to-noise ratio at 850um
113-116 F4.1 mJy F850 Flux density at 850um
118-120 F3.1 mJy e_F850 Error on flux density at 850um
123-127 F5.1 mJy F850D ?=-99.9 Deboosted flux density at 850um
129-133 F5.1 mJy e_F850D ?=-99.9 Error on Deboosted flux density
at 850um
135-139 F5.1 arcsec Dist ?=-99.9 Distance between 850um and 850um
detections
--------------------------------------------------------------------------------
Note (1): Fields as follows:
F2 = MAMMOTH-1
F4 = Jackpot
F6 = Fabulous
F8 = J0525-233
F10 = SDSSJ1209+1138
F12 = SDSSJ1025+0452
F14 = SDSSJ1557+1540
F16 = SDSSJ1342+1702
F18 = Q-0115-30
F20 = Q2355+0108
F22 = SDSSJ0819+0823
F24 = J015741-01062957
F26 = J020944+051713
F28 = J024401-013403
F30 = J033900-013318
F32 = J111113-080401
F34 = 193957-100241
F36 = J221527-161133
F38 = J230301-093930
F40 = J233446-090812
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Byte-by-byte Description of file: tab_850u.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Field Table number (F1-F40 odd numbers) (1)
5- 27 A23 --- Name850 Source name at 850um
28- 29 I2 h RAh Right ascension (J2000)
31- 32 I2 min RAm Right ascension (J2000)
34- 37 F4.1 s RAs Right ascension (J2000)
40 A1 --- DE- Declination sign (J2000)
41- 42 I2 deg DEd Declination (J2000)
44- 45 I2 arcmin DEm Declination (J2000)
47- 48 I2 arcsec DEs Declination (J2000)
52- 55 F4.1 --- S/N Signal-to-noise ratio
59- 62 F4.1 mJy F850 Flux density at 850um
64- 66 F3.1 mJy e_F850 Error on flux density at 850um
70- 73 F4.1 mJy F850D Deboosted flux density at 850um
74- 77 F4.1 mJy e_F850D Error on Deboosted flux density at 850um
81- 83 F3.1 arcsec ePos Error on position
87-109 A23 --- Name450 Counterpart name at 450um
110-113 F4.1 --- S/N450 Signal-to-noise ratio at 450um
116-118 I3 mJy F450 Flux density at 450um
120-121 I2 mJy e_F450 Error on flux density at 450um
123-125 I3 mJy F450D ?=-99 Deboosted flux density at 450um
128-130 I3 mJy e_F450D ?=-99 Error on Deboosted flux density at 450um
132-136 F5.1 arcsec Dist ?=-99.9 Distance between 850um and 450um
detections
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Note (1): Fields as follows:
F1 = MAMMOTH-1
F3 = Jackpot
F5 = Fabulous
F7 = J0525-233
F9 = SDSSJ1209+1138
F11 = SDSSJ1025+0452
F13 = SDSSJ1557+1540
F15 = SDSSJ1342+1702
F17 = Q-0115-30
F19 = Q2355+0108
F21 = SDSSJ0819+0823
F23 = J015741-01062957
F25 = J020944+051713
F27 = J024401-013403
F29 = J033900-013318
F31 = J111113-080401
F33 = 193957-100241
F35 = J221527-161133
F37 = J230301-093930
F39 = J233446-090812
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Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- Field Field
5- 13 F9.5 deg RAdeg Right Ascension of center (J2000)
14- 22 F9.5 deg DEdeg Declination of center (J2000)
24- 26 I3 --- Nx Number of pixels along X-axis
28- 30 I3 --- Ny Number of pixels along Y-axis
32- 54 A23 "datime" Obs.date Observation date
56- 62 F7.5 m lambda Wavelength
64- 67 I4 Kibyte size Size of FITS file
69- 93 A25 --- FileName Name of FITS file, in subdirectory fits
95-126 A32 --- Title Title of the FITS file
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Acknowledgements:
Fabrizio Arrigoni Battaia, arrigoni(at)mpa-garching.mpg.de
(End) Patricia Vannier [CDS] 27-Apr-2023