Universität zu Köln

Jameson, Katherine E., Bolatto, Alberto D., Wolfire, Mark, Warren, Steven R., Herrera-Camus, Rodrigo ORCID: 0000-0002-2775-0595, Croxall, Kevin ORCID: 0000-0002-5258-7224, Pellegrini, Eric, Smith, John-David ORCID: 0000-0003-1545-5078, Rubio, Monica, Indebetouw, Remy, Israel, Frank P., Meixner, Margaret, Roman-Duval, Julia ORCID: 0000-0001-6326-7069, van Loon, Jacco Th., Muller, Erik, Verdugo, Celia, Zinnecker, Hans and Okada, Yoko ORCID: 0000-0002-6838-6435 (2018). First Results from the Herschel and ALMA Spectroscopic Surveys of the SMC: The Relationship between [C II]-bright Gas and CO-bright Gas at Low Metallicity. Astrophys. J., 853 (2). BRISTOL: IOP PUBLISHING LTD. ISSN 1538-4357

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Abstract

The Small Magellanic Cloud (SMC) provides the only laboratory to study the structure of molecular gas at high resolution and low metallicity. We present results from the Herschel Spectroscopic Survey of the SMC (HS3), which mapped the key far-IR cooling lines [C II], [O I], [N II], and [O III] in five star-forming regions, and new ALMA 7 m array maps of (CO)-C-12 and (CO)-C-13 (2-1) with coverage overlapping four of the five HS3 regions. We detect [C II] and [O I] throughout all of the regions mapped. The data allow us to compare the structure of the molecular clouds and surrounding photodissociation regions using (CO)-C-13, (CO)-C-12, [C II], and [O I] emission at less than or similar to 10 '' (<3 pc) scales. We estimate A(V) using far-IR thermal continuum emission from dust and find that the CO/[C II] ratios reach the Milky Way value at high A(V) in the centers of the clouds and fall to similar to 1/5-1/10x the Milky Way value in the outskirts, indicating the presence of translucent molecular gas not traced by bright (CO)-C-12 emission. We estimate the amount of molecular gas traced by bright [C II] emission at low A(V) and bright (CO)-C-12 emission at high A(V). We find that most of the molecular gas is at low A(V) and traced by bright [C II] emission, but that faint (CO)-C-12 emission appears to extend to where we estimate that the H-2-to-H I transition occurs. By converting our H-2 gas estimates to a CO-to-H-2 conversion factor (X-CO), we show that X-CO is primarily a function of A(V), consistent with simulations and models of low-metallicity molecular clouds.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Jameson, Katherine E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bolatto, Alberto D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wolfire, Mark UNSPECIFIED UNSPECIFIED UNSPECIFIED Warren, Steven R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Herrera-Camus, Rodrigo UNSPECIFIED orcid.org/0000-0002-2775-0595 UNSPECIFIED Croxall, Kevin UNSPECIFIED orcid.org/0000-0002-5258-7224 UNSPECIFIED Pellegrini, Eric UNSPECIFIED UNSPECIFIED UNSPECIFIED Smith, John-David UNSPECIFIED orcid.org/0000-0003-1545-5078 UNSPECIFIED Rubio, Monica UNSPECIFIED UNSPECIFIED UNSPECIFIED Indebetouw, Remy UNSPECIFIED UNSPECIFIED UNSPECIFIED Israel, Frank P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Meixner, Margaret UNSPECIFIED UNSPECIFIED UNSPECIFIED Roman-Duval, Julia UNSPECIFIED orcid.org/0000-0001-6326-7069 UNSPECIFIED van Loon, Jacco Th. UNSPECIFIED UNSPECIFIED UNSPECIFIED Muller, Erik UNSPECIFIED UNSPECIFIED UNSPECIFIED Verdugo, Celia UNSPECIFIED UNSPECIFIED UNSPECIFIED Zinnecker, Hans UNSPECIFIED UNSPECIFIED UNSPECIFIED Okada, Yoko UNSPECIFIED orcid.org/0000-0002-6838-6435 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-196330
DOI:	10.3847/1538-4357/aaa4bb
Journal or Publication Title:	Astrophys. J.
Volume:	853
Number:	2
Date:	2018
Publisher:	IOP PUBLISHING LTD
Place of Publication:	BRISTOL
ISSN:	1538-4357
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SEST KEY PROGRAM; SMALL-MAGELLANIC-CLOUD; FAR-INFRARED SPECTROSCOPY; GIANT MOLECULAR CLOUDS; NEUTRAL ATOMIC PHASES; INTERSTELLAR-MEDIUM; PHOTODISSOCIATION REGIONS; GALAXIES DETECTION; SPITZER SURVEY; EMISSION-LINE Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/19633