Consequences of bursty star formation on galaxy observables at high redshifts

Alberto Domínguez, Brian Siana, Alyson M. Brooks, Charlotte R. Christensen, Gustavo Bruzual, Daniel P Stark, Anahita Alavi

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The star formation histories (SFHs) of dwarf galaxies are thought to be bursty, with large - order of magnitude - changes in the star formation rate on time-scales similar to O-star lifetimes. As a result, the standard interpretations of many galaxy observables (which assume a slowly varying SFH) are often incorrect. Here, we use the SFHs from hydrodynamical simulations to investigate the effects of bursty SFHs on sample selection and interpretation of observables and make predictions to confirm such SFHs in future surveys. First, because dwarf galaxies' star formation rates change rapidly, the mass-to-light ratio is also changing rapidly in both the ionizing continuum and, to a lesser extent, the non-ionizing ultraviolet continuum. Therefore, flux limited surveys are highly biased towards selecting galaxies in the burst phase and very deep observations are required to detect all dwarf galaxies at a given stellar mass. Second, we show that a log<inf>10</inf>[νL<inf>ν</inf>(1500 Å)/L<inf>Hα</inf>] > 2.5 implies a very recent quenching of star formation and can be used as evidence of stellar feedback regulating star formation. Third, we show that the ionizing continuum can be significantly higher than when assuming a constant SFH, which can affect the interpretation of nebular emission line equivalent widths and direct ionizing continuum detections. Finally, we show that a star formation rate estimate based on continuum measurements only (and not on nebular tracers such as the hydrogen Balmer lines) will not trace the rapid changes in star formation and will give the false impression of a star-forming main sequence with low dispersion.

Original languageEnglish (US)
Pages (from-to)839-848
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume451
Issue number1
DOIs
StatePublished - May 1 2015

Fingerprint

star formation
galaxies
history
histories
continuums
dwarf galaxies
star formation rate
O stars
mass to light ratios
tracer
hydrogen
stellar mass
timescale
tracers
bursts
prediction
quenching
simulation
rate
stars

Keywords

  • Galaxies: evolution
  • Galaxies: high-redshift
  • Galaxies: starburst

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Consequences of bursty star formation on galaxy observables at high redshifts. / Domínguez, Alberto; Siana, Brian; Brooks, Alyson M.; Christensen, Charlotte R.; Bruzual, Gustavo; Stark, Daniel P; Alavi, Anahita.

In: Monthly Notices of the Royal Astronomical Society, Vol. 451, No. 1, 01.05.2015, p. 839-848.

Research output: Contribution to journalArticle

Domínguez, A, Siana, B, Brooks, AM, Christensen, CR, Bruzual, G, Stark, DP & Alavi, A 2015, 'Consequences of bursty star formation on galaxy observables at high redshifts', Monthly Notices of the Royal Astronomical Society, vol. 451, no. 1, pp. 839-848. https://doi.org/10.1093/mnras/stv1001
Domínguez, Alberto ; Siana, Brian ; Brooks, Alyson M. ; Christensen, Charlotte R. ; Bruzual, Gustavo ; Stark, Daniel P ; Alavi, Anahita. / Consequences of bursty star formation on galaxy observables at high redshifts. In: Monthly Notices of the Royal Astronomical Society. 2015 ; Vol. 451, No. 1. pp. 839-848.
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