The Nature of Starbursts. I. The Star Formation Histories of Eighteen Nearby Starburst Dwarf Galaxies

McQuinn, Kristen B. W.; Skillman, Evan D.; Cannon, John; Dalcanton, Julianne J.; Dolphin, Andrew E.; Hidalgo, Sebastián L.; Holtzman, Jon A.; Stark, David; Weisz, Daniel R.; Williams, Benjamin F.

doi:10.1088/0004-637x/721/1/297

Cited by 183 publications

(246 citation statements)

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“…Several definitions of a starburst exist in the literature (e.g., Knapen & James 2009;McQuinn et al 2010;Bergvall et al 2015). The birthrate parameter, b = SFR/ SFR is often used, and compares the current SFR or the peak of the burst to the average SFR over the past Gyr or even the lifetime of the system.…”

Section: Discussionmentioning

confidence: 99%

Dark influences

Starkenburg

Helmi

Sales

2016

A&A

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Context. It has been proposed that mergers induce starbursts and lead to important morphological changes in galaxies. Most studies so far have focused on large galaxies, but dwarfs might also experience such events, since the halo mass function is scale-free in the concordance cosmological model. Notably, because of their low mass, most of their interactions will be with dark satellites. Aims. In this paper we follow the evolution of gas-rich disky dwarf galaxies as they experience a minor merger with a dark satellite. We aim to characterize the effects of such an interaction on the dwarf's star formation, morphology, and kinematical properties. Methods. We performed a suite of carefully set-up hydrodynamical simulations of dwarf galaxies that include dark matter, gas, and stars merging with a satellite consisting solely of dark matter. For the host system we vary the gas fraction, disk size and thickness, halo mass, and concentration, while we explore different masses, concentrations, and orbits for the satellite. Results. We find that the interactions cause strong starbursts of both short and long duration in the dwarfs. Their star formation rates increase by factors of a few to 10 or more. They are strongest for systems with extended gas disks and high gas fractions merging with a high-concentration satellite on a planar, radial orbit. In contrast to analogous simulations of Milky Way-mass galaxies, many of the systems experience strong morphological changes and become spheroidal even in the presence of significant amounts of gas. Conclusions. The simulated systems compare remarkably well with the observational properties of a large selection of irregular dwarf galaxies and blue compact dwarfs. This implies that mergers with dark satellites might well be happening but not be fully evident, and may thus play a role in the diversity of the dwarf galaxy population.

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Section: Discussionmentioning

confidence: 99%

Dark influences

Starkenburg

Helmi

Sales

2016

A&A

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“…Episodes of large star formation are intertwined with long quiescent phases. This result is inferred using fitting techniques on integrated galaxy spectra (e.g., Cid Fernandes 2007), color-magnitude diagrams of resolved stellar populations (McQuinn et al 2010a), and statistical arguments involving active and quiescent BCDs (Sánchez Almeida et al 2008). Convulsive SF histories fit in well the cold-flow accretion scenario.…”

Section: Kinematical Distortionsmentioning

confidence: 92%

Star formation sustained by gas accretion

Alméida

Elmegreen

Muñoz–Tuñón

et al. 2014

Astron Astrophys Rev

171

130

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Numerical simulations predict that metal-poor gas accretion from the cosmic web fuels the formation of disk galaxies. This paper discusses how cosmic gas accretion controls star formation, and summarizes the physical properties expected for the cosmic gas accreted by galaxies. The paper also collects observational evidence for gas accretion sustaining star formation. It reviews evidence inferred from neutral and ionized hydrogen, as well as from stars. A number of properties characterizing large samples of star-forming galaxies can be explained by metal-poor gas accretion, in particular, the relationship among stellar mass, metallicity, and star-formation rate (the so-called fundamental metallicity relationship). They are put forward and analyzed. Theory predicts gas accretion to be particularly important at high redshift, so indications based on distant objects are reviewed, including the global star-formation history of the universe, and the gas around galaxies as inferred from absorption features in the spectra of background sources.

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“…In particular, dwarf galaxies in nearby groups have been predominantly found to have similar properties to those of our close neighbors (e.g. Karachentsev et al 2002aKarachentsev et al ,b, 2003aKarachentsev et al ,b, 2004Karachentsev et al , 2007Trentham & Tully 2002;Karachentsev 2005;Sharina et al 2008;Bouchard et al 2009;Weisz et al 2008;Côté et al 2009;Dalcanton et al 2009;Koleva et al 2009;McQuinn et al 2009;McQuinn et al 2010;Crnojević et al 2010Crnojević et al , 2011bLianou et al 2010;Makarova et al 2010). A recent Hubble Space Telescope (HST) survey of dwarf galaxies (ANGST, Weisz et al 2011), comprising about 60 objects located within ∼4 Mpc, has led to a large compilation of color-magnitude diagrams (CMDs) of their resolved stellar populations.…”

Section: Introductionmentioning

confidence: 99%

A close look at the Centaurus A group of galaxies

Crnojević

Grebel

Cole

2012

A&A

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Aims. We study a sample of five dwarf irregular galaxies in the CenA/M 83 group, which are companions to the giant elliptical CenA. We aim at deriving their physical properties over their lifetime and compare them to those of dwarfs located in different environments. Methods. We use archival HST/ACS data and apply synthetic color-magnitude diagram fitting in order to reconstruct the past star formation activity of the target galaxies. Results. The average star formation rate for the studied galaxies ranges from 10 −3 M yr −1 up to ∼7 × 10 −2 M yr −1 , and their mean metallicities correlate with their luminosities (from [Fe/H] ∼ −1.4 up to ∼−1.0). The form of the star formation histories varies across the sample, with quiescent periods alternating with intermittent enhancements in the star formation (from a few up to several times the average lifetime value). The dwarfs in this sample formed ∼35% to 60% of their stellar content prior to ∼5 Gyr ago. Conclusions. The resulting star formation histories for the CenA companions are similar to those found for comparable Local Group and M 81 group dwarfs. We consider this sample of dwarfs together with five previously studied M 83 dwarf irregular companions. We find no trend of the average star formation rate with tidal index or distance from the main galaxy of the group. However, dwarfs with higher baryonic masses do show higher average star formation rates, underlining the importance of intrinsic properties in governing the evolution of these galaxies. On the other hand, there is also a clear trend when looking at the recent (∼0.5−1 Gyr) level of activity. Namely, dwarfs within a denser region of the group appear to have had their star formation quenched while dwarfs located in the group outskirts show a wide range of possible star formation rates, thus indicating that external processes play a fundamental role, complementary to mass, in shaping the star formation histories of dwarf galaxies.

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The Nature of Starbursts. I. The Star Formation Histories of Eighteen Nearby Starburst Dwarf Galaxies

Cited by 183 publications

References 100 publications

Dark influences

Dark influences

Star formation sustained by gas accretion

A close look at the Centaurus A group of galaxies

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