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Dust and Atomic Gas in Dwarf Irregular Galaxies of the M81 Group: The SINGS and THINGS View

Walter, Fabian and Cannon, John M. and Roussel, Hélène and Bendo, George J. and Calzetti, Daniela and Dale, Daniel A. and Draine, Bruce T. and Helou, George and Kennicutt, Robert C., Jr. and Moustakas, John and Rieke, George H. and Armus, Lee and Engelbracht, Charles W. and Gordon, Karl and Hollenbach, David J. and Lee, Janice and Li, Aigen and Meyer, Martin J. and Murphy, Eric J. and Regan, Michael W. and Smith, John-David T. and Brinks, Elias and de Blok, W. J. G. and Bigiel, Frank and Thornley, Michele D. (2007) Dust and Atomic Gas in Dwarf Irregular Galaxies of the M81 Group: The SINGS and THINGS View. Astrophysical Journal, 661 (1). pp. 102-114. ISSN 0004-637X. doi:10.1086/514807.

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We present observations of the dust and atomic gas phase in seven dwarf irregular galaxies of the M81 group from the Spitzer SINGS and VLA THINGS surveys. The Spitzer observations provide a first glimpse of the nature of the nonatomic ISM in these metal-poor (Z ~ 0.1 Z_☉), quiescent (SFR ~ 0.001-0.1 M_☉ yr^(-1)) dwarf galaxies. Most detected dust emission is restricted to H I column densities >1 × 10^(21) cm^(-2), and almost all regions of high H I column density (>2.5 × 10^(21) cm^(-2)) have associated dust emission. Spitzer spectroscopy of two regions in the brightest galaxies (IC 2574 and Holmberg II) show distinctly different spectral shapes and aromatic features, although the galaxies have comparable gas-phase metallicities. This result emphasizes that the strength of the aromatic features is not a simple linear function of metallicity. We estimate dust masses of ~10^(4)-10^(6) M_☉ for the M81 dwarf galaxies, resulting in an average dust-to-gas ratio (M_(dust)/M_(H I)) of ~3 × 10^(-4) (1.5 × 10^(-3) if only the H I that is associated with dust emission is considered); this is an order of magnitude lower than the typical value derived for the SINGS spirals. The dwarf galaxies are underluminous per unit star formation rate at 70 μm as compared to the more massive galaxies in SINGS by a factor of ~2. However, the average 70/160 μm ratio in the sample dwarf galaxies is higher than what is found in the other galaxies of the SINGS sample. This can be explained by a combination of a lower dust content in conjunction with a higher dust temperature in the dwarfs.

Item Type:Article
Related URLs:
URLURL TypeDescription
Walter, Fabian0000-0003-4793-7880
Calzetti, Daniela0000-0002-5189-8004
Dale, Daniel A.0000-0002-5782-9093
Draine, Bruce T.0000-0002-0846-936X
Helou, George0000-0003-3367-3415
Kennicutt, Robert C., Jr.0000-0001-5448-1821
Rieke, George H.0000-0003-2303-6519
Armus, Lee0000-0003-3498-2973
Lee, Janice0000-0002-2278-9407
Murphy, Eric J.0000-0001-7089-7325
Smith, John-David T.0000-0003-1545-5078
Brinks, Elias0000-0002-7758-9699
Additional Information:© 2007 American Astronomical Society. Print publication: Issue 1 (2007 May 20); received 2006 September 26; accepted for publication 2007 February 12. Some of the data presented here are part of the Spitzer Space Telescope Legacy Science Program The Spitzer Nearby Galaxies Survey (SINGS), which was made possible by NASA through contract 1224769 issued by JPL/Caltech under NASA contract 1407. This work was also supported in part by NSF grant AST 04-06883.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NSFAST 04-06883
Subject Keywords:galaxies: dwarf; galaxies: individual (DDO 53, DDO 165, Holmberg I, Holmberg II, IC 2574, M81 dwA, M81 dwB); galaxies: irregular; galaxies: ISM; infrared: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20091119-084804447
Persistent URL:
Official Citation:Dust and Atomic Gas in Dwarf Irregular Galaxies of the M81 Group: The SINGS and THINGS View Fabian Walter, John M. Cannon, Hélène Roussel, George J. Bendo, Daniela Calzetti, Daniel A. Dale, Bruce T. Draine, George Helou, Robert C. Kennicutt, Jr., John Moustakas, George H. Rieke, Lee Armus, Charles W. Engelbracht, Karl Gordon, David J. Hollenbach, Janice Lee, Aigen Li, Martin J. Meyer, Eric J. Murphy, Michael W. Regan, John-David T. Smith, Elias Brinks, W. J. G. de Blok, Frank Bigiel, and Michele D. Thornley 2007 ApJ 661 102-114 doi: 10.1086/514807
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16755
Deposited By: Jason Perez
Deposited On:20 Nov 2009 16:56
Last Modified:08 Nov 2021 23:29

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