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Date and Time of the Query: 2019-05-20 T03:51:09 PDT
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For refcode 2010ApJ...721..297M:
Retrieve 18 NED objects in this reference.
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Copyright by American Astronomical Society. Reproduced by permission
2010ApJ...721..297M The Nature of Starbursts. I. The Star Formation Histories of Eighteen Nearby Starburst Dwarf Galaxies McQuinn, Kristen B. W.; Skillman, Evan D.; Cannon, John M.; Dalcanton, Julianne; Dolphin, Andrew; Hidalgo-Rodriguez, Sebastian; Holtzman, Jon; Stark, David; Weisz, Daniel; Williams, Benjamin Abstract. We use archival Hubble Space Telescope observations of resolved stellar populations to derive the star formation histories (SFHs) of 18 nearby starburst dwarf galaxies. In this first paper, we present the observations, color-magnitude diagrams (CMDs), and the SFHs of the 18 starburst galaxies, based on a homogeneous approach to the data reduction, differential extinction, and treatment of photometric completeness. We adopt a star formation rate (SFR) threshold normalized to the average SFR of the individual system as a metric for classifying starbursts in SFHs derived from resolved stellar populations. This choice facilitates finding not only the currently bursting galaxies but also "fossil" bursts increasing the sample size of starburst galaxies in the nearby (D < 8 Mpc) universe. Thirteen of the eighteen galaxies are experiencing ongoing bursts and five galaxies show fossil bursts. From our reconstructed SFHs, it is evident that the elevated SFRs of a burst are sustained for hundreds of Myr with variations on small timescales. A long >100 Myr temporal baseline is thus fundamental to any starburst definition or identification method. The longer lived bursts rule out rapid "self-quenching" of starbursts on global scales. The bursting galaxies' gas consumption timescales are shorter than the Hubble time for all but one galaxy confirming the short-lived nature of starbursts based on fuel limitations. Additionally, we find that the strength of the H{alpha} emission usually correlates with the CMD-based SFR during the last 4-10 Myr. However, in four cases, the H{alpha} emission is significantly less than what is expected for models of starbursts; the discrepancy is due to the SFR changing on timescales of a few Myr. The inherently short timescale of the H{alpha} emission limits identifying galaxies as starbursts based on the current characteristics which may or may not be representative of the recent SFH of a galaxy. Key words: galaxies: dwarf, galaxies: evolution, galaxies: individual: Antlia ESO154-023 SBS1415+437 UGC 4483 UGC 9128 NGC 625 NGC 784 NGC 1569 NGC 2366 NGC 4068 NGC 4163 NGC 4214 NGC 4449 NGC 5253 NGC 6456 NGC 6789 NGC 6822 IC 4662, galaxies: starburst
Retrieve 18 NED objects in this reference.
Please click here for ADS abstract

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