An ALMA Band 7 survey of SDSS Herschel quasars in Stripe 82: I. The properties of the 870 micron counterparts

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00642102" target="_blank" >RIV/67985815:_____/25:00642102 - isvavai.cz</a>

Výsledek na webu

<a href="https://hdl.handle.net/11104/0372065" target="_blank" >https://hdl.handle.net/11104/0372065</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202555105" target="_blank" >10.1051/0004-6361/202555105</a>

Jazyk výsledku

angličtina

Název v původním jazyce

An ALMA Band 7 survey of SDSS Herschel quasars in Stripe 82: I. The properties of the 870 micron counterparts

Popis výsledku v původním jazyce

Context. Over the past 15 years, studies of quasars in the far-infrared (FIR) have reported host luminosities ranging from 10(12) to 10(14) L-circle dot. These luminosities, often derived from Herschel/SPIRE photometry, suggest star formation rates (SFRs) of up to several thousand M-circle dot yr(-1), positioning them among the most luminous starburst galaxies in the Universe. However, owing 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. Aims. The aim of the present work is to unambiguously identify the submillimetre (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. Methods. 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 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. Results. 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 similar to 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 sufficiently exciting 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.

Název v anglickém jazyce

An ALMA Band 7 survey of SDSS Herschel quasars in Stripe 82: I. The properties of the 870 micron counterparts

Popis výsledku anglicky

Context. Over the past 15 years, studies of quasars in the far-infrared (FIR) have reported host luminosities ranging from 10(12) to 10(14) L-circle dot. These luminosities, often derived from Herschel/SPIRE photometry, suggest star formation rates (SFRs) of up to several thousand M-circle dot yr(-1), positioning them among the most luminous starburst galaxies in the Universe. However, owing 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. Aims. The aim of the present work is to unambiguously identify the submillimetre (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. Methods. 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 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. Results. 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 similar to 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 sufficiently exciting 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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

<a href="/cs/project/LM2023059" target="_blank" >LM2023059: Atacama Large Millimeter /submillimeter Array – účast České republiky</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

702

Číslo periodika v rámci svazku

Oct.

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

12

Strana od-do

A183

Kód UT WoS článku

001597841900010

EID výsledku v databázi Scopus

2-s2.0-105020023852