Strong FUV fields drive the [CII]/FIR deficit in z~3 dusty, star-forming galaxies

Abstract

We present 0.15-arcsec (1 kpc) resolution ALMA observations of the [CII] 157.74 um line and rest-frame 160-um continuum emission in two z~3 dusty, star-forming galaxies - ALESS 49.1 and ALESS 57.1, combined with resolved CO(3-2) observations. In both sources, the [CII] surface brightness distribution is dominated by a compact core $\le$1 kpc in radius, a factor of 2-3 smaller than the extent of the CO(3-2) emission. In ALESS 49.1, we find an additional extended (8-kpc radius), low surface-brightness [CII] component. Based on an analysis of mock ALMA observations, the [CII] and 160-um continuum surface brightness distributions are inconsistent with a single-Gaussian surface brightness distribution with the same size as the CO(3-2) emission. The [CII] rotation curves flatten at $\simeq$2 kpc radius, suggesting the kinematics of the central regions are dominated by a baryonic disc. Both galaxies exhibit a strong [CII]/FIR deficit on 1-kpc scales, with FIR-surface-brightness to [CII]/FIR slope steeper than in local star-forming galaxies. A comparison of the [CII]/CO(3-2) observations with PDR models suggests a strong FUV radiation field ($G_0\sim 10^4$) and high gas density ($n(\mathrm{H})\sim 10^4-10^5$ cm${}^{-3}$) in the central regions of ALESS 49.1 and 57.1. The most direct interpretation of the pronounced [CII]/FIR deficit is a thermal saturation of the C+ fine-structure levels at temperatures $\ge$500 K, driven by the strong FUV field.

Submitted to ApJ

References in corpus (20)

• A simple model to interpret the ultraviolet, optical and infrared emission from galaxies
• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• An ALMA survey of Sub-millimeter Galaxies in the Extended Chandra Deep Field South: Physical properties derived from ultraviolet-to-radio modelling
• An optimized algorithm for multi-scale wideband deconvolution of radio astronomical images
• Kiloparsec-scale dust disks in high-redshift luminous submillimeter galaxies
• A Kiloparsec-Scale Hyper-Starburst in a Quasar Host Less than 1 Gigayear after the Big Bang
• Very extended cold gas, star formation and outflows in the halo of a bright QSO at z>6
• The nature of the [CII] emission in dusty star-forming galaxies from the SPT survey
• The kiloparsec-scale star formation law at redshift 4: wide-spread, highly efficient star formation in the dust-obscured starburst galaxy GN20
• An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: Spectroscopic redshifts
• The VLA 1.4GHz Survey of the Extended Chandra Deep Field South: First Data Release
• The Spatially Resolved [CII] Cooling Line Deficit in Galaxies
• The Origins of [CII] Emission in Local Star-forming Galaxies
• A spatially resolved study of cold dust, molecular gas, HII regions, and stars in the $z=2.12$ submillimeter galaxy ALESS67.1
• Physical conditions of the interstellar medium of high-redshift, strongly lensed submillimetre galaxies from the Herschel-ATLAS
• Strong C+ emission in galaxies at z~1-2: Evidence for cold flow accretion powered star formation in the early Universe
• The interstellar medium in high-redshift submillimeter galaxies as probed by infrared spectroscopy
• The AT-LESS CO(1-0) survey of submillimetre galaxies in the Extended Chandra Deep Field South: First results on cold molecular gas in galaxies at z ~ 2
• High Spectral and Spatial Resolution Observations of the PDR Emission in the NGC2023 Reflection Nebula with SOFIA and APEX
• Detection of molecular gas in an ALMA [CII]-identified Submillimetre Galaxy at z = 4.44

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