Strong Far-ultraviolet Fields Drive the [C ii]/Far-infrared Deficit in z ∼ 3 Dusty, Star-forming Galaxies

Matus Rybak; G. Calistro Rivera; J. A. Hodge; Ian Smail; F. Walter; P. Van Der Werf; E. Da Cunha; Chian Chou Chen; H. Dannerbauer; R. J. Ivison; A. Karim; J. M. Simpson; A. M. Swinbank; J. L. Wardlow

doi:10.3847/1538-4357/ab0e0f

Strong Far-ultraviolet Fields Drive the [C ii]/Far-infrared Deficit in z ∼ 3 Dusty, Star-forming Galaxies

Matus Rybak, G. Calistro Rivera, J. A. Hodge, Ian Smail, F. Walter, P. Van Der Werf, E. Da Cunha, Chian Chou Chen, H. Dannerbauer, R. J. Ivison, A. Karim, J. M. Simpson, A. M. Swinbank, J. L. Wardlow

Research output: Contribution to journal › Article › peer-review

48 Citations (Scopus)

Abstract

We present 0.″15 (1 kpc) resolution ALMA observations of the [C ii] 157.74 μm line and rest-frame 160 μm 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 [C ii] surface brightness distribution is dominated by a compact core ≤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 [C ii] component. Based on an analysis of mock ALMA observations, the [C ii] and 160 μm continuum surface brightness distributions are inconsistent with a single-Gaussian surface brightness distribution with the same size as the CO (3-2) emission. The [C ii] rotation curves flatten at ≃2 kpc radius, suggesting that the kinematics of the central regions are dominated by a baryonic disk. Both galaxies exhibit a strong [C ii]/far-IR (FIR) deficit on 1 kpc scales, with FIR surface brightness to [C ii]/FIR slope steeper than in local star-forming galaxies. A comparison of the [C ii]/CO (3-2) observations with photodissociation region models suggests a strong far-UV (FUV) radiation field (G ₀ ∼ 10⁴) and high gas density (n(H) ∼ 10⁴-10⁵ cm^-3) in the central regions of ALESS 49.1 and ALESS 57.1. The most direct interpretation of the pronounced [C ii]/FIR deficit is a thermal saturation of the C⁺ fine-structure levels at temperatures ≥500 K, driven by the strong FUV field.

Original language	English
Article number	112
Journal	Astrophysical Journal
Volume	876
Issue number	2
DOIs	https://doi.org/10.3847/1538-4357/ab0e0f
Publication status	Published - 10 May 2019

Access to Document

10.3847/1538-4357/ab0e0f

Cite this

Rybak, M., Rivera, G. C., Hodge, J. A., Smail, I., Walter, F., Van Der Werf, P., Da Cunha, E., Chen, C. C., Dannerbauer, H., Ivison, R. J., Karim, A., Simpson, J. M., Swinbank, A. M., & Wardlow, J. L. (2019). Strong Far-ultraviolet Fields Drive the [C ii]/Far-infrared Deficit in z ∼ 3 Dusty, Star-forming Galaxies. Astrophysical Journal, 876(2), Article 112. https://doi.org/10.3847/1538-4357/ab0e0f

@article{0163175426f04a288c5196a38ba7e099,

title = "Strong Far-ultraviolet Fields Drive the [C ii]/Far-infrared Deficit in z ∼ 3 Dusty, Star-forming Galaxies",

abstract = "We present 0.″15 (1 kpc) resolution ALMA observations of the [C ii] 157.74 μm line and rest-frame 160 μm 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 [C ii] surface brightness distribution is dominated by a compact core ≤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 [C ii] component. Based on an analysis of mock ALMA observations, the [C ii] and 160 μm continuum surface brightness distributions are inconsistent with a single-Gaussian surface brightness distribution with the same size as the CO (3-2) emission. The [C ii] rotation curves flatten at ≃2 kpc radius, suggesting that the kinematics of the central regions are dominated by a baryonic disk. Both galaxies exhibit a strong [C ii]/far-IR (FIR) deficit on 1 kpc scales, with FIR surface brightness to [C ii]/FIR slope steeper than in local star-forming galaxies. A comparison of the [C ii]/CO (3-2) observations with photodissociation region models suggests a strong far-UV (FUV) radiation field (G 0 ∼ 104) and high gas density (n(H) ∼ 104-105 cm-3) in the central regions of ALESS 49.1 and ALESS 57.1. The most direct interpretation of the pronounced [C ii]/FIR deficit is a thermal saturation of the C+ fine-structure levels at temperatures ≥500 K, driven by the strong FUV field.",

keywords = "galaxies: high-redshift, galaxies: star formation, submillimeter: galaxies",

author = "Matus Rybak and Rivera, {G. Calistro} and Hodge, {J. A.} and Ian Smail and F. Walter and {Van Der Werf}, P. and {Da Cunha}, E. and Chen, {Chian Chou} and H. Dannerbauer and Ivison, {R. J.} and A. Karim and Simpson, {J. M.} and Swinbank, {A. M.} and Wardlow, {J. L.}",

year = "2019",

month = may,

day = "10",

doi = "10.3847/1538-4357/ab0e0f",

language = "English",

volume = "876",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2",

}

Rybak, M, Rivera, GC, Hodge, JA, Smail, I, Walter, F, Van Der Werf, P, Da Cunha, E, Chen, CC, Dannerbauer, H, Ivison, RJ, Karim, A, Simpson, JM, Swinbank, AM & Wardlow, JL 2019, 'Strong Far-ultraviolet Fields Drive the [C ii]/Far-infrared Deficit in z ∼ 3 Dusty, Star-forming Galaxies', Astrophysical Journal, vol. 876, no. 2, 112. https://doi.org/10.3847/1538-4357/ab0e0f

TY - JOUR

T1 - Strong Far-ultraviolet Fields Drive the [C ii]/Far-infrared Deficit in z ∼ 3 Dusty, Star-forming Galaxies

AU - Rybak, Matus

AU - Rivera, G. Calistro

AU - Hodge, J. A.

AU - Smail, Ian

AU - Walter, F.

AU - Van Der Werf, P.

AU - Da Cunha, E.

AU - Chen, Chian Chou

AU - Dannerbauer, H.

AU - Ivison, R. J.

AU - Karim, A.

AU - Simpson, J. M.

AU - Swinbank, A. M.

AU - Wardlow, J. L.

PY - 2019/5/10

Y1 - 2019/5/10

N2 - We present 0.″15 (1 kpc) resolution ALMA observations of the [C ii] 157.74 μm line and rest-frame 160 μm 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 [C ii] surface brightness distribution is dominated by a compact core ≤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 [C ii] component. Based on an analysis of mock ALMA observations, the [C ii] and 160 μm continuum surface brightness distributions are inconsistent with a single-Gaussian surface brightness distribution with the same size as the CO (3-2) emission. The [C ii] rotation curves flatten at ≃2 kpc radius, suggesting that the kinematics of the central regions are dominated by a baryonic disk. Both galaxies exhibit a strong [C ii]/far-IR (FIR) deficit on 1 kpc scales, with FIR surface brightness to [C ii]/FIR slope steeper than in local star-forming galaxies. A comparison of the [C ii]/CO (3-2) observations with photodissociation region models suggests a strong far-UV (FUV) radiation field (G 0 ∼ 104) and high gas density (n(H) ∼ 104-105 cm-3) in the central regions of ALESS 49.1 and ALESS 57.1. The most direct interpretation of the pronounced [C ii]/FIR deficit is a thermal saturation of the C+ fine-structure levels at temperatures ≥500 K, driven by the strong FUV field.

AB - We present 0.″15 (1 kpc) resolution ALMA observations of the [C ii] 157.74 μm line and rest-frame 160 μm 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 [C ii] surface brightness distribution is dominated by a compact core ≤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 [C ii] component. Based on an analysis of mock ALMA observations, the [C ii] and 160 μm continuum surface brightness distributions are inconsistent with a single-Gaussian surface brightness distribution with the same size as the CO (3-2) emission. The [C ii] rotation curves flatten at ≃2 kpc radius, suggesting that the kinematics of the central regions are dominated by a baryonic disk. Both galaxies exhibit a strong [C ii]/far-IR (FIR) deficit on 1 kpc scales, with FIR surface brightness to [C ii]/FIR slope steeper than in local star-forming galaxies. A comparison of the [C ii]/CO (3-2) observations with photodissociation region models suggests a strong far-UV (FUV) radiation field (G 0 ∼ 104) and high gas density (n(H) ∼ 104-105 cm-3) in the central regions of ALESS 49.1 and ALESS 57.1. The most direct interpretation of the pronounced [C ii]/FIR deficit is a thermal saturation of the C+ fine-structure levels at temperatures ≥500 K, driven by the strong FUV field.

KW - galaxies: high-redshift

KW - galaxies: star formation

KW - submillimeter: galaxies

UR - http://www.scopus.com/inward/record.url?scp=85067316169&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/ab0e0f

DO - 10.3847/1538-4357/ab0e0f

M3 - Article

SN - 0004-637X

VL - 876

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 112

ER -

Strong Far-ultraviolet Fields Drive the [C ii]/Far-infrared Deficit in z ∼ 3 Dusty, Star-forming Galaxies

Abstract

Access to Document

Other files and links

Fingerprint

Cite this