J/A+A/702/A183 Stripe 82 QSOs ALMA Band 7 detections (Hatziminaoglou+, 2025)
An ALMA Band 7 survey of SDSS/Herschel quasars in Stripe 82.
I. The properties of the 870 micron counterparts.
Hatziminaoglou E., Messias H., Souza R., Borkar A., Farrah D., Feltre A.,
Magdis G., Pitchford L.K., Perez-Fournon I.
<Astron. Astrophys. 702, A183 (2025)>
=2025A&A...702A.183H 2025A&A...702A.183H (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Millimetric/submm sources ; Photometry, millimetric/submm
Keywords: techniques: interferometric - galaxies: active - quasars: general -
galaxies: starburst - radio continuum: galaxies
Abstract:
Over the past 15 years, studies of quasars in the far-infrared
(FIR) have reported host luminosities ranging from 1012 to 1014
solar luminosities. These luminosities, often derived from
Herschel/SPIRE photometry, suggest star formation rates (SFRs) of up
to several thousand solar masses per year, positioning them among the
most luminous starburst galaxies in the Universe. However, due to the
limited spatial resolution of SPIRE, there is considerable uncertainty
regarding whether the FIR emission originates from the quasar itself,
nearby sources at the same redshift, or unrelated sources within the
SPIRE beam. To resolve this uncertainty, high-resolution observations
at wavelengths close to the SPIRE coverage are required to pinpoint
the true source of the FIR emission.
The aim of the present work is to unambiguously identify the
submillimeter (submm) counterparts of a statistical sample of
FIR-bright SDSS quasars and estimate the real multiplicity rates among
these systems. We study the evolution of the incidence of
multiplicities with redshift, FIR properties and "balnicity". Based on
these multiplicities, we assess the importance of mergers as triggers
for concomitant accretion onto supermassive black holes (SMBHs) and
extreme star formation.
We conducted ALMA Band 7 continuum observations of 152 SDSS FIR-bright
quasars in Stripe 82, covering redshifts between 1 and 4, with a
spatial resolution of 0.8". We identified all the sources detected in
the Band 7 maps at or above 5 sigma and performed forced photometry on
the phase centre for the few quasars that were not detected otherwise.
Additionally, we examined the coarse Band 7 spectra for any
serendipitous detections of CO and other transitions.
We find that in approximately 60% of all cases, the submm emission
originates from a single counterpart within the SPIRE beam, centred on
the optical coordinates of the quasar. The rate of multiplicity
increases with redshift, rising by a factor of 2.5 between redshifts 1
and 2.5. The incidence of multiplicities is consistent among broad
absorption line (BAL) quasars and non-BAL quasars. The multiplicities
observed in a fraction of the sample indicate that, while mergers are
known to enhance gas inflow efficiency, there must be viable
alternatives for driving synchronous SMBH growth and intense star
formation in isolated systems. Additionally, we report the
serendipitous detection of two CO(6-5) and three CO(7-6) transitions
in five quasars at redshifts between 1 and 1.4, out of the eight such
transitions expected based on the spectral setup and the redshifts of
the objects in the sample. Higher transitions, although expected in a
fraction of the sample, are not detected, indicating that the quasars
are not exciting sufficiently the gas in their hosts. Finally, we also
detect a potential emission of H2O, HCN(10-9) or a combination of both
in the spectrum of a quasar at redshift 1.67.
Description:
This catalogue lists the ALMA Band 7 detections in the fields of the
152 SDSS quasars in Stripe 82. The data include SDSS Name, coordinates
of the light centroid position, the distance to the phase centre, the
signal-to-noise at the peak, the peak intensity and integrated flux,
for aperture photometry and from imfit, and sigma of the extractions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 99 209 ALMA Band 7 detections
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See also:
J/A+A/525/A37 : Variability indexes of QSOs in SDSS Stripe 82
(Meusinger+, 2011)
J/MNRAS/440/476 : Low-redshift quasars in SDSS Stripe 82 (Falomo+, 2014)
J/MNRAS/441/1802 : Low-redshift QSOs in SDSS Stripe 82 (Karhunen+, 2014)
J/ApJ/768/105 : z∼5 QSO luminosity function from SDSS Stripe 82
(McGreer+, 25)
J/ApJ/824/70 : UV-FIR SED results of SDSS QSOs and their hosts
(Dong+, 2016)
J/AJ/154/269 : A new photo-z method for quasars in Stripe 82 (Yang+, 2017)
J/ApJ/861/37 : Luminous WISE-selected quasars in SDSS Stripe 82
(Glikman+, 2018)
J/A+A/611/A97 : Photometric quasar candidates in Stripe 82
(Pasquet-Itam+, 2018)
J/ApJ/900/58 : Opt-IR LC compilation of DES Stripe 82 quasars (Yang+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- SDSS SDSS Name (HHMMSS.ss+DDMMSS,s)
20- 21 I2 h RAh Right Ascension (ICRS) at Ep=J2000
23- 24 I2 min RAm Right Ascension (ICRS) at Ep=J2000
26- 30 F5.2 s RAs Right Ascension (ICRS) at Ep=J2000
32 A1 --- DE- Declination sign (ICRS) at Ep=J2000
33- 34 I2 deg DEd Declination (ICRS) at Ep=J2000
36- 37 I2 arcmin DEm Declination (ICRS) at Ep=J2000
39- 43 F5.2 arcsec DEs Declination (ICRS) at Ep=J2000
45- 50 F6.3 arcsec D2P Distance to Phase Centre
52- 55 F4.1 --- SNR Signal-to-noise ratio
57- 61 F5.2 mJy/beam Iap Peak intensity at 870um, aperture photometry
63- 66 F4.2 mJy/beam e_Iap Error on Iap
68- 72 F5.2 mJy Sap Integrated flux at 870um, aperture photometry
74- 77 F4.2 mJy e_Sap Error on Sap
79- 83 F5.2 mJy/beam Iimfit ?=- Peak intensity at 870um, IMFIT
85- 88 F4.2 mJy/beam e_Iimfit ?=- Error on Iimfit
90- 94 F5.2 mJy Simfit ?=- Integrated flux at 870um, IMFIT
96- 99 F4.2 mJy e_Simfit ?=- Error on Simfit
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Acknowledgements:
Evanthia Hatziminaoglou, ehatzimi(at)eso.org
Based on observations obtained with ALMA under Program ID 2022.1.00029.S.
(End) Patricia Vannier [CDS] 06-Aug-2025