Molecular Gas in Infrared Ultraluminous Qso Hosts

Xia, X. Y.; Gao, Yu; Hao, Cai-Na; Tan, Qinghua; Mao, Sui Ann; Omont, A.; Flaquer, B. Ocaña; Léon, S.; Cox, P.

doi:10.1088/0004-637x/750/2/92

Cited by 60 publications

(86 citation statements)

References 74 publications

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“…However, recent studies find lower values of R 21 on the global scales of nearby galactic disks (R 21 0.8; Leroy et al 2013;Rosolowsky et al 2015;Saintonge et al 2017). Ocaña Flaquer et al (2010 report R 21 ≈ 0.6 for nearby radio galaxies, and some low-redshift quasars can reach R 21 ≈ 0.5 (Husemann et al 2017), while in IR-luminous quasars R 21 ≈ 0.4 − 1.2, with a mean value of ∼ 0.8 (Xia et al 2012). Therefore, our low-redshift quasars exhibit R 21 values fully consistent with those derived from global measurements of nearby inactive and active galaxies.…”

Section: Measurements From the Literaturesupporting

confidence: 87%

An ALMA CO(2–1) Survey of Nearby Palomar–Green Quasars

Shangguan

Bauer

et al. 2020

ApJS

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The properties of the molecular gas can shed light on the physical conditions of quasar host galaxies and the effect of feedback from accreting supermassive black holes. We present a new CO(2-1) survey of 23 z < 0.1 Palomar-Green quasars conducted with the Atacama Large Millimeter/submillimeter Array. CO emission was successfully detected in 91% (21/23) of the objects, from which we derive CO luminosities, molecular gas masses, and velocity line widths. Together with CO(1-0) measurements in the literature for 32 quasars (detection rate 53%), there are 15 quasars with both CO(1-0) and CO(2-1) measurements and in total 40 sources with CO measurements. We find that the line ratio R 21 ≡ L CO(2-1) /L CO(1-0) is subthermal, broadly consistent with nearby galaxies and other quasars previously studied. No clear correlation is found between R 21 and the intensity of the interstellar radiation field or the luminosity of the active nucleus. As with the general galaxy population, quasar host galaxies exhibit a strong, tight, linear L IR -L CO(1-0) relation, with a normalization consistent with that of starburst systems. We investigate the molecular-to-total gas mass fraction with the aid of total gas masses inferred from dust masses previously derived from infrared observations. Although the scatter is considerable, the current data do not suggest that the CO-to-H 2 conversion factor of quasar host galaxies significantly differs from that of normal star-forming galaxies.

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Section: Measurements From the Literaturesupporting

confidence: 87%

An ALMA CO(2–1) Survey of Nearby Palomar–Green Quasars

Shangguan

Bauer

et al. 2020

ApJS

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“…An alternate approach is to use L FIR (40-500 μm or 42.5-11.5 μm) instead of L IR (8-1000 μm), as dust emission in this regime should come primarily from heating by young stars. Xia et al (2012) conclude that L FIR /L CO in a sample of 17 QSOs is similar to the ratios in local ULIRGs (many of which are known to host obscured AGNs), and Evans et al (2006) finds high L FIR /L CO ratios in QSOs relative to the IRAS galaxies.…”

Section: Introductionmentioning

confidence: 72%

Early Science With the Large Millimeter Telescope: Exploring the Effect of Agn Activity on the Relationships Between Molecular Gas, Dust, and Star Formation

Kirkpatrick

Pope

Aretxaga

et al. 2014

ApJ

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The molecular gas, H 2 , that fuels star formation in galaxies is difficult to observe directly. As such, the ratio of L IR to L CO is an observational estimate of the star formation rate compared with the amount of molecular gas available to form stars, which is related to the star formation efficiency and the inverse of the gas consumption timescale. We test what effect an IR luminous active galactic nucleus (AGN) has on the ratio L IR /L CO in a sample of 24 intermediate redshift galaxies from the 5 mJy Unbiased Spitzer Extragalactic Survey (5MUSES). We obtain new CO(1-0) observations with the Redshift Search Receiver on the Large Millimeter Telescope. We diagnose the presence and strength of an AGN using Spitzer IRS spectroscopy. We find that removing the AGN contribution to L tot IR results in a mean L SF IR /L CO for our entire sample consistent with the mean L IR /L CO derived for a large sample of star forming galaxies from z ∼ 0-3. We also include in our comparison the relative amount of polycyclic aromatic hydrocarbon emission for our sample and a literature sample of local and high-redshift ultra luminous infrared galaxies and find a consistent trend between L 6.2 /L SF IR and L SF IR /L CO , such that small dust grain emission decreases with increasing L SF IR /L CO for both local and high-redshift dusty galaxies.

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“…2 (see table caption for details on different source populations). The grey symbols represent z< 1 measurements: the 0.2<z<1 ULIRG sample by Combes et al 2011 and2012b (crosses), low-z quasars from the Hamburg-ESO QSO survey (diamonds, Bertram et al 2007), PG quasars (squares, Evans et al 2001, Evans 2006, Scoville et al 2003, nearby spiral galaxies (upward triangles), low-z spirals, starburst galaxies, and ULIRGs (downward and upward triangles, Gao& Solomon 2004a,b), the z< 0.2 IR QSO sample by Xia et al (2012) and 0.04<z<0.11 ULIRG sample by Chung et al (2009, open circles). The full line is a fit to all data points which gives a slope of 1.35±0.04.…”

Section: Acknowledgementsmentioning

confidence: 99%

Cool Gas in High-Redshift Galaxies

Carilli

Walter

2013

Annu. Rev. Astron. Astrophys.

1,114

1,251

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Over the last decade, observations of the cool interstellar medium in distant galaxies via molecular and atomic fine structure line emission has gone from a curious look into a few extreme, rare objects, to a mainstream tool to study galaxy formation, out to the highest redshifts. Molecular gas has now been observed in close to 200 galaxies at z > 1, including numerous AGN hostgalaxies out to z ∼ 7, highly starforming sub-millimeter galaxies (median redshift z ∼ 2.5), and increasing samples of 'main-sequence' color-selected star forming galaxies at z∼1.5-2.5. Studies have moved well beyond simple detections, to dynamical imaging at kpc-scale resolution, and multi-line, multi-species studies that determine the physical conditions in the interstellar medium in early galaxies. Observations of the cool gas are the required complement to studies of the stellar density and star formation history of the Universe, as they reveal the phase of the interstellar medium that immediately preceeds star formation in galaxies. Current observations suggest that the order of magnitude increase in the cosmic star formation rate density from z ∼ 0 to 2 is commensurate with a similar increase in the gas to stellar mass ratio in star forming disk galaxies. Progress has been made on determining the CO luminosity to H2 mass conversion factor at high-z, and the dicotomy between high versus low values for main sequence versus starburst galaxies, respectively, appears to persist with increasing redshift, with a likely dependence on metallicity and other local physical conditions. Studies of atomic fine structure line emission are rapidly progressing, with some tens of galaxies detected in the exceptionally bright [C II] 158µm line to date. The [C II] line is proving to be a unique tracer of galaxy dynamics in the early Universe, and, together with other atomic fine structure lines, has the potential to be the most direct means of obtaining spectroscopic redshifts for the first galaxies during cosmic reionization.

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Molecular Gas in Infrared Ultraluminous Qso Hosts

Cited by 60 publications

References 74 publications

An ALMA CO(2–1) Survey of Nearby Palomar–Green Quasars

An ALMA CO(2–1) Survey of Nearby Palomar–Green Quasars

Early Science With the Large Millimeter Telescope: Exploring the Effect of Agn Activity on the Relationships Between Molecular Gas, Dust, and Star Formation

Cool Gas in High-Redshift Galaxies

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