Dust and gas content of high-redshift galaxies hosting obscured AGN in the CDF-S

Abstract

Obscured AGN represent a significant fraction of the entire AGN population, especially at high redshift (~70% at z=3--5). They are often characterized by the presence of large gas and dust reservoirs that are thought to sustain and possibly obscure vigorous star formation processes that make these objects shine at far-IR and sub-mm wavelengths. We exploit ALMA Cycle 4 observations of the continuum (~2.1mm) and high-J CO emission of a sample of six X-ray selected SMGs hosting an obscured AGN at z_spec>2.5 in the 7 Ms CDF-S. We measured the masses and sizes of the dust and molecular gas and we derived the gas density and column density on the basis of a uniform sphere geometry. Finally, we compared the measured column densities with those derived from the Chandra X-ray spectra. We detected both the continuum and line emission for three sources for which we measured both the flux density and size. For the undetected sources, we derived an upper limit on the flux density. We found that the detected galaxies are rich in gas and dust (molecular gas mass in the range <0.5 - 2.7 x 10^10 M_sun for α_CO=0.8 and up to ~2 x 10^11~M_sun for α_CO=6.5, and dust mass <0.9 - 4.9 x 10^8 M_sun) and compact (gas major axis 2.1-3.0 kpc, dust major axis 1.4-2.7 kpc). The column densities associated with the ISM are on the order of 10^(23-24) cm-2, which is comparable with those derived from the X-ray spectra. For the detected sources we also derived dynamical masses in the range 0.8 - 3.7 x 10^10 M_sun. We conclude that the ISM of high redshift galaxies can substantially contribute to nuclear obscuration up to the Compton-thick (>10^24 cm-2) regime. In addition, we found that all the detected sources show a velocity gradient reminding one rotating system, even though two of them show peculiar features in their morphology that can be associated with a chaotic, possibly merging, structure.

15 pages, 6 figures, 7 tables. Accepted for publication in A&A

References in corpus (23)

• Cosmic Star Formation History
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• The Herschel view of the dominant mode of galaxy growth from z=4 to the present day
• Combined CO & Dust Scaling Relations of Depletion Time and Molecular Gas Fractions with Cosmic Time, Specific Star Formation Rate and Stellar Mass
• The Chandra Deep Field-South Survey: 7 Ms Source Catalogs
• The 1% Concordance Hubble Constant
• Kiloparsec-scale dust disks in high-redshift luminous submillimeter galaxies
• CO excitation of normal star forming galaxies out to z=1.5 as regulated by the properties of their interstellar medium
• High-redshift AGN in the Chandra Deep Fields: the obscured fraction and space density of the sub-$L_{\ast }$ population
• Tracing the reionization epoch with ALMA: [CII] emission in z~7 galaxies
• An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South: Near-infrared morphologies and stellar sizes
• Radial distribution of dust, stars, gas, and star-formation rate in DustPedia face-on galaxies
• ALMA reveals metals yet no dust within multiple components in CR7
• Strong FUV fields drive the [CII]/FIR deficit in z~3 dusty, star-forming galaxies
• The X-ray emission of z>2.5 active galactic nuclei can be obscured by their host galaxies
• The Molecular Gas Reservoirs of $z\sim 2$ Galaxies: A comparison of CO(1-0) and dust-based molecular gas masses
• CO Emission in Infrared-Selected Active Galactic Nuclei
• Impact of X-rays on CO emission from high-z galaxies
• The high-redshift (z>3) AGN population in the 4 Ms Chandra Deep Field South
• CO excitation in the Seyfert galaxy NGC 34: stars, shock or AGN driven?
• CO excitation in the Seyfert galaxy NGC7130

Cited by in corpus (32)

• Supermassive Black Holes at High Redshift are Expected to be Obscured by their Massive Host Galaxies' Inter Stellar Medium
• The WISSH QSOs project IX. Cold gas content and environment of luminous QSOs at z~2.4-4.7
• Mock catalogs for the extragalactic X-ray sky: simulating AGN surveys with Athena and with the AXIS probe
• Revealing the relation between black-hole growth and host-galaxy compactness among star-forming galaxies
• The rocky road to quiescence: compaction and quenching of quasar host galaxies at z~2
• GA-NIFS: Early-stage feedback in a heavily obscured AGN at $z=4.76$
• AGN impact on the molecular gas in galactic centers as probed by CO lines
• "Little red dots" cannot reside in the same dark matter halos as comparably luminous unobscured quasars
• A unified model for the clustering of quasars and galaxies at $z\approx 6$
• Unveiling the nature of 11 dusty star-forming galaxies at the peak of cosmic star formation history
• AGN X-ray luminosity function and absorption function in the Early Universe ($3\le z\le 6$)
• X-ray properties and obscured fraction of AGN in the J1030 Chandra field
• Comparing the host galaxy ages of X-ray selected AGN in COSMOS: Obscured AGN are associated with older galaxies
• The Obscured Fraction of Quasars at Cosmic Noon
• The effect of active galactic nuclei on the cold interstellar medium in distant star-forming galaxies
• Fast SMBH growth in the SPT2349--56 protocluster at $z=4.3$
• Piercing through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields. II. Are Highly Obscured AGNs the Missing Link in the Merger-Triggered AGN-Galaxy Coevolution Models?
• Molecular Outflows in z > 6 QSO Hosts Driven by Star Formation
• The Black Hole Mass Function Across Cosmic Times II. Heavy Seeds and (Super)Massive Black Holes
• A deep 1.4 GHz survey of the J1030 equatorial field: a new window on radio source populations across cosmic time
• A big red dot at cosmic noon
• Chandra Observations of Excess Fe K$\alpha$ Line Emission in Galaxies with High Star Formation Rates: X-ray Reflection on Galaxy Scales?
• BASS. XLIX. Characterization of highly luminous and obscured AGNs: local X-ray and [NeV]$\lambda$3426 emission in comparison with the high-redshift Universe
• Massive black holes in high-redshift Lyman Break Galaxies
• X-ray Redshifts for Obscured Active Galactic Nuclei with AXIS Deep and Intermediate Surveys
• The Dawn of Black Holes
• Shedding the envelope: JWST reveals a kiloparsec-scale [OIII]-weak Balmer shell around a z=7.64 quasar
• LBT-MODS spectroscopy of high-redshift candidates in the Chandra J1030 field. A newly discovered z$\sim$2.8 large scale structure
• A first look at quasar-galaxy clustering at $z\simeq 7.3$
• The Additional Representative Images for Legacy (ARI-L) project for the ALMA Science Archive
• Selection of Compton-thick AGN from a hard photometric sample using XMM-Newton observations
• High-Energy Neutrino Production in Clusters of Galaxies