Skip to main content

Spatially Resolved Dust, Gas, and Star Formation in the Dwarf Magellanic Irregular NGC 4449

Author(s): Calzetti, D; Wilson, GW; Draine, Bruce T.; Roussel, H; Johnson, KE; et al

To refer to this page use:
Abstract: We investigate the relation between gas and star formation in subgalactic regions, similar to 360. pc to similar to 1.5. kpc in size, within the nearby starburst dwarf NGC 4449, in order to separate the underlying relation from the effects of sampling at varying spatial scales. Dust and gas mass surface densities are derived by combining new observations at 1.1. mm, obtained with the AzTEC instrument on the Large Millimeter Telescope, with archival infrared images in the range 8-500 mu m from the Spitzer Space Telescope and the Herschel Space Observatory. We extend the dynamic range of our millimeter (and dust) maps at the faint end, using a correlation between the far-infrared/millimeter colors F(70)/F(1100) (and F(160)/F(1100)) and the mid-infrared color F(8)/F(24) that we establish for the first time for this and other galaxies. Supplementing our data with maps of the extinction-corrected star formation rate (SFR) surface density, we measure both the SFR-molecular gas and the SFR-total. gas relations in NGC 4449. We find that the SFR-molecular. gas relation is described by a power law with an exponent that decreases from similar to 1.5 to similar to 1.2 for increasing region size, while the exponent of the SFR-total. gas relation remains constant with a value of similar to 1.5 independent of region size. We attribute the molecular law behavior to the increasingly better sampling of the molecular cloud mass function at larger region sizes; conversely, the total gas law behavior likely results from the balance between the atomic and molecular gas phases achieved in regions of active star formation. Our results indicate a nonlinear relation between SFR and gas surface density in NGC 4449, similar to what is observed for galaxy samples.
Publication Date: 10-Jan-2018
Electronic Publication Date: 12-Jan-2018
Citation: Calzetti, D, Wilson, GW, Draine, BT, Roussel, H, Johnson, KE, Heyer, MH, Wall, WF, Grasha, K, Battisti, A, Andrews, JE, Kirkpatrick, A, Rosa Gonzalez, D, Vega, O, Puschnig, J, Yun, M, Ostlin, G, Evans, AS, Tang, Y, Lowenthal, J, Sanchez-Arguelles, D. (2018). Spatially Resolved Dust, Gas, and Star Formation in the Dwarf Magellanic Irregular NGC 4449. ASTROPHYSICAL JOURNAL, 852 (10.3847/1538-4357/aaa1e2
DOI: doi:10.3847/1538-4357/aaa1e2
ISSN: 0004-637X
EISSN: 1538-4357
Type of Material: Journal Article
Journal/Proceeding Title: ASTROPHYSICAL JOURNAL
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.
Notes: Supplementary data available at and

Items in OAR@Princeton are protected by copyright, with all rights reserved, unless otherwise indicated.