Stacked Average Far-infrared Spectrum of Dusty Star-forming Galaxies from the Herschel/SPIRE Fourier Transform Spectrometer∗
Open Access
- 9 October 2017
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 848 (1), 30
- https://doi.org/10.3847/1538-4357/aa8cc7
Abstract
We present stacked average far-infrared spectra of a sample of 197 dusty star-forming galaxies (DSFGs) at using about 90% of the Herschel Space Observatory SPIRE Fourier Transform Spectrometer (FTS) extragalactic data archive based on 3.5 years of science operations. These spectra explore an observed-frame 447–1568 GHz frequency range, allowing us to observe the main atomic and molecular lines emitted by gas in the interstellar medium. The sample is subdivided into redshift bins, and a subset of the bins are stacked by infrared luminosity as well. These stacked spectra are used to determine the average gas density and radiation field strength in the photodissociation regions (PDRs) of DSFGs. For the low-redshift sample, we present the average spectral line energy distributions of CO and H2O rotational transitions and consider PDR conditions based on observed [C i] 370 and 609 μm, and CO (7-6) lines. For the high-z () sample, PDR models suggest a molecular gas distribution in the presence of a radiation field that is at least a factor of 103 larger than the Milky Way and with a neutral gas density of roughly – cm−3. The corresponding PDR models for the low-z sample suggest a UV radiation field and gas density comparable to those at high-z. Given the challenges in obtaining adequate far-infrared observations, the stacked average spectra we present here will remain the measurements with the highest signal-to-noise ratio for at least a decade and a half until the launch of the next far-infrared facility.This publication has 136 references indexed in Scilit:
- EXPLAINING THE [C II]157.7 μm DEFICIT IN LUMINOUS INFRARED GALAXIES—FIRST RESULTS FROM AHERSCHEL/PACS STUDY OF THE GOALS SAMPLEThe Astrophysical Journal, 2013
- Cool Gas in High-Redshift GalaxiesAnnual Review of Astronomy and Astrophysics, 2013
- AHerschelview of the far-infrared properties of submillimetre galaxiesAstronomy & Astrophysics, 2012
- GOODS–Herschel: an infrared main sequence for star-forming galaxiesAstronomy & Astrophysics, 2011
- Dust and molecular content of the lensed quasar, MG0751+2716, atz = 3.2Astronomy & Astrophysics, 2007
- 350 μm Dust Emission from High‐Redshift QuasarsThe Astrophysical Journal, 2006
- The H+ region contribution to [C II] 158- m emissionMonthly Notices of the Royal Astronomical Society, 2006
- Dense Molecular Gas and the Role of Star Formation in the Host Galaxies of Quasi?stellar ObjectsThe Astronomical Journal, 2006
- Heating of interstellar gas by large molecules or small grainsThe Astrophysical Journal, 1988
- H2O heating in molecular clouds - Line transfer and thermal balance in a warm dusty mediumThe Astrophysical Journal, 1983