THE KENNICUTT-SCHMIDT RELATION IN EXTREMELY METAL-POOR DWARF GALAXIES

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Mercedes E Filho (Author) FEUP; Sanchez Almeida, JS (Author) Other; Amorin, R (Author) Other; Munoz Tunon, C (Author) Other; Elmegreen, BG (Author) Other; Elmegreen, DM (Author) Other

Journal

Title: Astrophysical Journal

Vol. 820

Final page: 109

ISSN: 0004-637X

Publisher: American Astronomical Society

Indexing

ISI Web of Knowledge - 22 Citations

Scopus - 26 Citations

Other information

Authenticus ID: P-00K-CS1

DOI: 10.3847/0004-637x/820/2/109

Abstract (EN): The Kennicutt-Schmidt (KS) relation between the gas mass and star formation rate (SFR) describes the star formation regulation in disk galaxies. It is a function of gas metallicity, but the low-metallicity regime of the KS diagram is poorly sampled. We have analyzed data for a representative set of extremely metal-poor galaxies (XMPs), as well as auxiliary data, and compared these to empirical and theoretical predictions. The majority of the XMPs possess high specific SFRs, similar to high-redshift star-forming galaxies. On the KS plot, the XMP H I. data occupy the same region as dwarfs. and extend the relation for low surface brightness galaxies. Considering the H I. gas alone, a considerable fraction of the XMPs already fall off the KS law. Significant quantities of "dark" H-2 mass (i.e., not traced by CO) would imply that XMPs possess low star formation efficiencies (SFEgas). Low SFEgas in XMPs may be the result of the metal-poor nature of the H I. gas. Alternatively, the H I. reservoir may be largely inert, the star formation being dominated by cosmological accretion. Time lags between gas accretion and star formation may also reduce the apparent SFEgas, as may galaxy winds, which can expel most of the gas into the intergalactic medium. Hence, on global scales, XMPs could be H I-dominated, high-specific-SFR (greater than or similar to 10(-10) yr(-1)), low-SFEgas (less than or similar to 10(-9) yr(-1)) systems, in which the total H I. mass is likely not a good predictor of the total H-2 mass, nor of the SFR.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 15