Infrared Properties of a Complete Sample of Star-Forming Dwarf Galaxies

Abstract

We present a study of a large, statistically complete sample of star-forming dwarf galaxies using mid-infrared observations from the {\it Spitzer Space Telescope}. The relationships between metallicity, star formation rate (SFR) and mid-infrared color in these systems show that the galaxies span a wide range of properties. However, the galaxies do show a deficit of 8.0 \um\ polycyclic aromatic hydrocarbon emission as is apparent from the median 8.0 \um\ luminosity which is only 0.004 \lstarf\ while the median $B$-band luminosity is 0.05 \lstarb. Despite many of the galaxies being 8.0 \um\ deficient, there is about a factor of 4 more extremely red galaxies in the [3.6] $-$ [8.0] color than for a sample of normal galaxies with similar optical colors. We show correlations between the [3.6] $-$ [8.0] color and luminosity, metallicity, and to a lesser extent SFRs that were not evident in the original, smaller sample studied previously. The luminosity--metallicity relation has a flatter slope for dwarf galaxies as has been indicated by previous work. We also show a relationship between the 8.0 \um\ luminosity and the metallicity of the galaxy which is not expected given the competing effects (stellar mass, stellar population age, and the hardness of the radiation field) that influence the 8.0 \um\ emission. This larger sample plus a well-defined selection function also allows us to compute the 8.0 \um\ luminosity function and compare it with the one for the local galaxy population. Our results show that below 10${}^9$ $L$\solar, nearly all the 8.0 \um\ luminosity density of the local universe arises from dwarf galaxies that exhibit strong \ha\ emission -- i.e., 8.0 \um\ and \ha\ selection identify similar galaxy populations despite the deficit of 8.0 \um\ emission observed in these dwarfs.

arXiv comment13 pages, 11 figures, Published in ApJ

References in corpus (38)

• The chemical composition of the Sun
• The Global Schmidt Law in Star Forming Galaxies
• The Origin of the Mass--Metallicity Relation: Insights from 53,000 Star-Forming Galaxies in the SDSS
• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• The Spitzer Space Telescope Mission
• Stellar mass-to-light ratios and the Tully-Fisher relation
• The Sixth Data Release of the Sloan Digital Sky Survey
• SINGS: The SIRTF Nearby Galaxies Survey
• The Spitzer Local Volume Legacy: Survey Description and Infrared Photometry
• An Ultraviolet-to-Radio Broadband Spectral Atlas of Nearby Galaxies
• Metallicity Effects on Dust Properties in Starbursting Galaxies
• Metallicity Effects on Mid-Infrared Colors and the 8 micron PAH Emission in Galaxies
• The Evolving Luminosity Function of Red Galaxies
• Oxygen and Nitrogen in Isolated Dwarf Irregular Galaxies
• Mid Infrared Properties of Low Metallicity Blue Compact Dwarf Galaxies From Spitzer/IRS
• Stellar Evolutionary Effects on the Abundances of PAH and SN-Condensed Dust in Galaxies
• The Spitzer Deep, Wide-Field Survey
• The IRAC Shallow Survey
• The Extraordinary Mid-infrared Spectrum of the Blue Compact Dwarf Galaxy SBS0335-052
• The PAH Emission Deficit In Low-Metallicity Galaxies - A Spitzer View
• Metal Abundances of KISS Galaxies III. Nebular Abundances for Fourteen Galaxies and the Luminosity-Metallicity Relationship for HII Galaxies
• Mid-Infrared Galaxy Morphology Along the Hubble Sequence
• Spectroscopic study of blue compact galaxies V. oxygen abundance and the metallicity-luminosity relation
• The KPNO International Spectroscopic Survey. I. Description of the Survey
• Metal Abundances of KISS Galaxies. IV. Galaxian Luminosity-Metallicity Relations in the Optical and Near-IR
• Metal Abundances of KISS Galaxies. I. Coarse Metal Abundances and the Metallicity-Luminosity Relation
• Spatial Distribution of Warm Dust in Early-Type Galaxies
• The Diverse Infrared Properties of a Complete Sample of Star-Forming Dwarf Galaxies
• The Spitzer Space Telescope First-Look Survey: KPNO MOSAIC-1 R-band Images and Source Catalogs
• The Local Galaxy 8 micron Luminosity Function
• The KPNO International Spectroscopic Survey. II. H-alpha Selected Survey List 1
• Luminosity-Metallicity Relations for Blue Compact Dwarf Galaxies in the Optical and Near-Infrared
• Dust in the Extremely Metal-Poor Blue Compact Dwarf Galaxy IZw18: The Spitzer Mid-Infrared View
• Mid-Infrared Galaxy Luminosity Functions from the AGN and Galaxy Evolution Survey
• Stellar Mass Estimation Based on IRAC Photometry for Spitzer SWIRE-field Galaxies
• Dust Properties and Star-Formation Rates in Star-Forming Dwarf Galaxies
• The Global, Local and Cluster Galaxy Luminosity Function
• The Spitzer View of Low-Metallicity Star Formation: I. Haro 3

Cited by in corpus (2)

• Spitzer Local Volume Legacy (LVL) SEDs and Physical Properties
• Comparing Infrared Star-Formation Rate Indicators with Optically-Derived Quantities