Library
local_library Home Repository

PRUSSIC

I. A JVLA survey of HCN, HCO+, and HNC (1–0) emission in z 3 dusty galaxies: Low dense-gas fractions in high-redshift star-forming galaxies

Journal Article (2022)
Author(s)

Matus Rybak (Universiteit Leiden, TU Delft - Tera-Hertz Sensing)

JA Hodges (Universiteit Leiden)

T. R. Greve3 (University College London, Dawning Information Industry Co., Ltd, Technical University of Denmark (DTU))

D. Riechers (Universität zu Köln)

I. Lamperti (Centro de Astrobiología (INTA-CSIC))

J. van Marrewijk (Universiteit Leiden, European Southern Observatory)

F. Walter (Max Planck Institute for Astronomy)

J. Wagg (SKA Observatory)

P. P. van der Werf (Universiteit Leiden)

Research Group
Tera-Hertz Sensing
Copyright
© 2022 M. Rybak, JA Hodges, T. R. Greve3, D. Riechers, I. Lamperti, J. van Marrewijk, F. Walter, J. Wagg, P. P. van der Werf
DOI related publication
https://doi.org/10.1051/0004-6361/202243894
More Info
expand_more
Publication Year
2022
Language
English
Copyright
© 2022 M. Rybak, JA Hodges, T. R. Greve3, D. Riechers, I. Lamperti, J. van Marrewijk, F. Walter, J. Wagg, P. P. van der Werf
Research Group
Tera-Hertz Sensing
Volume number
667
Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Abstract

Dusty star-forming galaxies (DSFGs) at redshift z ≥ 1 are among the most vigorously star-forming galaxies in the Universe. However, their dense (≥10
5cm
-3) gas phase - typically traced by HCN(1-0) - remains almost entirely unexplored: only two DSFGs have been detected in HCN(1-0) to date. We present the results of a Karl G. Jansky Very Large Array survey of the J = 1-0 transition of HCN, HCO+, and HNC(1-0) in six strongly lensed DSFGs at z = 2:5-3:3, effectively doubling the number of DSFGs with deep observations of these lines. We detect HCN(1-0) emission in one source (J1202+5354, 4.6 σ), with a tentative HCO+(1-0) detection in another (J1609+6045, 3.3). Spectral stacking yields strict upper limits on the HCN/FIR (≤3:6 × 10
-4) and HCN/CO(1-0) ratios (≤0.045). The inferred HCN/FIR ratios (a proxy for the star-formation efficiency) are consistent with those in z ∼ 0 far-infrared-luminous starbursts. However, the HCN/CO ratios - a proxy for the dense-gas fraction - are a factor of a few lower than suggested by the two previous DSFG detections. Our results imply that most DSFGs have low dense-gas fractions. A comparison with theoretical models of star-forming galaxies indicates that the bulk of gas in DSFGs is at lower densities (≈10
2cm
-3), similar to normal star-forming galaxies, rather than ultraluminous starbursts.