The WISSH quasars project

Bischetti, M.; Piconcelli, E.; Feruglio, C.; Duras, F.; Bongiorno, A.; Carniani, Stefano; Marconi, A.; Pappalardo, C.; Schneider, Raffaella; Travascio, A.; Valiante, Rosa; Vietri, G.; Zappacosta, L.; Fiore, F.

doi:10.1051/0004-6361/201833249

Cited by 25 publications

(37 citation statements)

References 79 publications

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“…However, it should be noted that the gas fractions derived for the IR QSOs in our sample are largely affected by the uncertainties of dynamical mass, e.g., the relatively smaller CO size compared to the full CO flux distribution that adopted for the dynamical mass estimates would lead to an overestimation of gas fraction (see Section 3.5). Similar results have been obtained for z ∼ 6 QSOs detected in CO emission, with a median value of M gas /M dyn = 0.16 (e.g., Wang et al 2010Wang et al , 2016Feruglio et al 2018). For comparison, the gas fraction of molecular gas to total baryonic mass of M gas /(M + M gas ) is found to have a mean value of about 0.3 in z = 1 main sequence galaxies, and the fraction increases with look-back time (e.g., Tan et al 2013;Schinnerer et al 2016;Magdis et al 2017;Tacconi et al 2018).…”

Section: Discussion 41 Host Galaxy Propertiessupporting

confidence: 84%

Resolving the Interstellar Medium in Ultraluminous Infrared QSO Hosts with ALMA

Tan

Gao

Kohno

et al. 2019

ApJ

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We present ALMA observations of the CO(1−0) line and 3-mm continuum emission in eight ultraluminous infrared (IR) quasi-stellar objects (QSOs) at z = 0.06−0.19. All eight IR QSO hosts are clearly resolved in their CO molecular gas emission with a median source size of 3.2 kpc, and seven out of eight sources are detected in 3-mm continuum, which is found to be more centrally concentrated with respect to molecular gas with sizes of 0.4−1.0 kpc. Our observations reveal a diversity of CO morphology and kinematics for the IR QSO systems which can be roughly classified into three categories, rotating gas disk with ordered velocity gradient, compact CO peak with disturbed velocity, and multiple CO distinct sources undergoing a merger between luminous QSO and a companion galaxy separated by a few kpc. The molecular gas in three of IR QSO hosts are found to be rotation-dominated with the ratio of the maximum rotation velocity to the local velocity dispersion of V rot /σ = 4 − 6. Basic estimates of the dynamical masses within the CO-emitting regions give masses between 7.4 × 10 9 and 6.9 × 10 10 M . We find an increasing trend between BH mass accretion rate and star formation rate (SFR) over three orders of magnitude in far-IR luminosity/SFR, in line with the correlation between QSO bolometric luminosity and SF activity, indicative of a likely direct connection between AGN and SF activity over galaxy evolution timescales.

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Section: Discussion 41 Host Galaxy Propertiessupporting

confidence: 84%

Resolving the Interstellar Medium in Ultraluminous Infrared QSO Hosts with ALMA

Tan

Gao

Kohno

et al. 2019

ApJ

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“…Indeed, some studies of quasar environments at z 4 report the detection of close submillimeter galaxies (SMGs) companions on scales of R 0.5 cMpc (e.g. Trakhtenbrot et al 2017;Decarli et al 2017;Bischetti et al 2018), some of which are totally extincted or at least very faint in the rest-frame UV. The acquisition of data at radio/submillimeter wavelengths in our quasar fields would allow one to explore this possibility, and would allow measurement of the clustering properties of both optical and dusty galaxy populations around quasars simultaneously.…”

Section: Discussionmentioning

confidence: 99%

Clustering of Lyα Emitters around Quasars at z ∼ 4*

García-Vergara

Barrientos

Battaia

2019

ApJ

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The strong observed clustering of z > 3.5 quasars indicates they are hosted by massive (M halo 10 12 h −1 M ) dark matter halos. Assuming quasars and galaxies trace the same large-scale structures, this should also manifest as strong clustering of galaxies around quasars. Previous work on highredshift quasar environments, mostly focused at z > 5, have failed to find convincing evidence for these overdensities. Here we conduct a survey for Lyman alpha emitters (LAEs) in the environs of 17 quasars at z ∼ 4 probing scales of R 7 h −1 Mpc. We measure an average LAE overdensity around quasars of 1.4 for our full sample, which we quantify by fitting the quasar-LAE cross-correlation function. We find consistency with a power-law shape with correlation length of r QG 0 = 2.78 +1.16 −1.05 h −1 cMpc for a fixed slope of γ = 1.8. We also measure the LAE auto-correlation length and find r GG 0 = 9.12 +1.32 −1.31 h −1 cMpc (γ = 1.8), which is 3.3 times higher than the value measured in blank fields. Taken together our results clearly indicate that LAEs are significantly clustered around z ∼ 4 quasars. We compare the observed clustering with the expectation from a deterministic bias model, whereby LAEs and quasars probe the same underlying dark matter overdensities, and find that our measurements fall short of the predicted overdensities by a factor of 2.1. We discuss possible explanations for this discrepancy including largescale quenching or the presence of excess dust in galaxies near quasars. Finally, the large cosmic variance from field-to-field observed in our sample (10/17 fields are actually underdense) cautions one from over-interpreting studies of z ∼ 6 quasar environments based on a single or handful of quasar fields.

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“…One FIR-bright source, J1404, presents an unusual [C II] double peak that could signal a late-stage merger. Bischetti et al (2018) found three companions around their targeted z=4.4 quasar, two of which have double-peaked line emission, while in Willott et al (2017), the high spectral and spatial resolution allows them to attribute different peaks in the [C II] line to the quasar source, a 5 kpc separated companion, and a "central excess" component between the two.…”

Section: Major Mergers Among Hostsmentioning

confidence: 99%

ALMA Observations of Quasar Host Galaxies at z ≃ 4.8

Nguyen

Lira

Trakhtenbrot

et al. 2020

ApJ

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We present ALMA Band 7 data of the [C II]l m 157.74 m emission line and underlying far-IR (FIR) continuum for 12 luminous quasars at  z 4.8 powered by fast-growing supermassive black holes (SMBHs). Our total sample consists of 18 quasars, 12 of which are presented here for the first time. The new sources consist of six Herschel/SPIRE-detected systems, which we define as "FIR-bright" sources, and six Herschel/SPIRE-undetected systems, which we define as "FIR-faint" sources. We determine dust masses for the quasars hosts of-  M M 0.2 25.0 10 dust 8 , implying interstellar medium gas masses comparable to the dynamical masses derived from the [C II] kinematics. It is found that, on average, the Mg II line is blueshifted by~-500 km s 1 with respect to the [C II] emission line, which is also observed when complementing our observations with data from the literature. We find that all of our FIR-bright subsample and most of the FIR-faint objects lie above the main sequence of star-forming galaxies atz 5. We detect companion submillimeter galaxies for two sources, both FIR-faint, with a range of projected distances of-20 60 kpc and typical velocity shifts of | | D- v 200 km s 1 from the quasar hosts. Of our total sample of 18 quasars, 5/18 are found to have dust-obscured star-forming companions.

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The WISSH quasars project

Cited by 25 publications

References 79 publications

Resolving the Interstellar Medium in Ultraluminous Infrared QSO Hosts with ALMA

Resolving the Interstellar Medium in Ultraluminous Infrared QSO Hosts with ALMA

Clustering of Lyα Emitters around Quasars at z ∼ 4*

ALMA Observations of Quasar Host Galaxies at z ≃ 4.8

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