eprintid: 10093776
rev_number: 15
eprint_status: archive
userid: 608
dir: disk0/10/09/37/76
datestamp: 2020-04-27 15:13:43
lastmod: 2021-10-01 23:52:10
status_changed: 2020-04-27 15:13:43
type: article
metadata_visibility: show
creators_name: Schirm, MRP
creators_name: Wilson, CD
creators_name: Parkin, TJ
creators_name: Kamenetzky, J
creators_name: Glenn, J
creators_name: Rangwala, N
creators_name: Spinoglio, L
creators_name: Pereira-Santaella, M
creators_name: Baes, M
creators_name: Barlow, MJ
creators_name: Clements, DL
creators_name: Cooray, A
creators_name: De Looze, I
creators_name: Karczewski, OL
creators_name: Madden, SC
creators_name: Rémy-Ruyer, A
creators_name: Wu, R
title: Herschel-SPIRE Fourier Transform Spectrometer observations of excited CO and [C I] in the Antennae (NGC 4038/39): warm and cold molecular gas
ispublished: pub
divisions: UCL
divisions: B04
divisions: C06
divisions: F60
keywords: galaxies: individual (NGC 4038, NGC 4039), galaxies: interactions, infrared: galaxies, ISM: molecules, submillimeter: galaxies
note: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
abstract: We present Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) observations of the Antennae (NGC 4038/39), a well-studied, nearby (22 Mpc), ongoing merger between two gas-rich spiral galaxies. The SPIRE-FTS is a low spatial ( FWHM ~ 19''-43'') and spectral (~1.2 GHz) resolution mapping spectrometer covering a large spectral range (194-671 μm, 450-1545 GHz). We detect five CO transitions (J = 4-3 to J = 8-7), both [C I] transitions, and the [N II] 205 μm transition across the entire system, which we supplement with ground-based observations of the CO J = 1-0, J = 2-1, and J = 3-2 transitions and Herschel Photodetecting Array Camera and Spectrometer (PACS) observations of [C II] and [O I] 63 μm. Using the CO and [C I] transitions, we perform both a local thermodynamic equilibrium (LTE) analysis of [C I] and a non-LTE radiative transfer analysis of CO and [C I] using the radiative transfer code RADEX along with a Bayesian likelihood analysis. We find that there are two components to the molecular gas: a cold (T kin ~ 10-30 K) and a warm (T kin gsim 100 K) component. By comparing the warm gas mass to previously observed values, we determine a CO abundance in the warm gas of x CO ~ 5 × 10–5. If the CO abundance is the same in the warm and cold gas phases, this abundance corresponds to a CO J = 1-0 luminosity-to-mass conversion factor of αCO ~ 7 M ☉ pc–2 (K km s–1)–1 in the cold component, similar to the value for normal spiral galaxies. We estimate the cooling from H2, [C II], CO, and [O I] 63 μm to be ~0.01 L ☉/M ☉. We compare photon-dominated region models to the ratio of the flux of various CO transitions, along with the ratio of the CO flux to the far-infrared flux in NGC 4038, NGC 4039, and the overlap region. We find that the densities recovered from our non-LTE analysis are consistent with a background far-ultraviolet field of strength G 0 ~ 1000. Finally, we find that a combination of turbulent heating, due to the ongoing merger, and supernova and stellar winds are sufficient to heat the molecular gas.
date: 2014-02-01
date_type: published
official_url: https://doi.org/10.1088/0004-637X/781/2/101
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 926989
doi: 10.1088/0004-637X/781/2/101
lyricists_name: Barlow, Michael
lyricists_id: MJBAR75
actors_name: Barlow, Michael
actors_id: MJBAR75
actors_role: owner
full_text_status: public
publication: The Astrophysical Journal
volume: 781
number: 2
article_number: 101
citation:        Schirm, MRP;    Wilson, CD;    Parkin, TJ;    Kamenetzky, J;    Glenn, J;    Rangwala, N;    Spinoglio, L;                                         ... Wu, R; + view all <#>        Schirm, MRP;  Wilson, CD;  Parkin, TJ;  Kamenetzky, J;  Glenn, J;  Rangwala, N;  Spinoglio, L;  Pereira-Santaella, M;  Baes, M;  Barlow, MJ;  Clements, DL;  Cooray, A;  De Looze, I;  Karczewski, OL;  Madden, SC;  Rémy-Ruyer, A;  Wu, R;   - view fewer <#>    (2014)    Herschel-SPIRE Fourier Transform Spectrometer observations of excited CO and [C I] in the Antennae (NGC 4038/39): warm and cold molecular gas.                   The Astrophysical Journal , 781  (2)    , Article 101.  10.1088/0004-637X/781/2/101 <https://doi.org/10.1088/0004-637X%2F781%2F2%2F101>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10093776/1/schirm2013_1312.2522.pdf