The star formation burstiness and ionizing efficiency of low-mass galaxies
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
The star formation burstiness and ionizing efficiency of low-mass galaxies. / Atek, Hakim; Furtak, Lukas J.; Oesch, Pascal; van Dokkum, Pieter; Reddy, Naveen; Contini, Thierry; Illingworth, Garth; Wilkins, Stephen.
In: Monthly Notices of the Royal Astronomical Society, Vol. 511, No. 3, 25.02.2022, p. 4464-4479.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - The star formation burstiness and ionizing efficiency of low-mass galaxies
AU - Atek, Hakim
AU - Furtak, Lukas J.
AU - Oesch, Pascal
AU - van Dokkum, Pieter
AU - Reddy, Naveen
AU - Contini, Thierry
AU - Illingworth, Garth
AU - Wilkins, Stephen
PY - 2022/2/25
Y1 - 2022/2/25
N2 - We investigate the burstiness of star formation and the ionizing efficiency of a large sample of galaxies at 0.7 < z < 1.5 using HST grism spectroscopy and deep ultraviolet (UV) imaging in the GOODS-N and GOODS-S fields. The star formation history (SFH) in these strong emission-line low-mass galaxies indicates an elevated star formation rate (SFR) based on the H alpha emission line at a given stellar mass when compared to the standard main sequence. Moreover, when comparing the H alpha and UV SFR indicators, we find that an excess in SFRH alpha compared to SFRUV is preferentially observed in lower mass galaxies below 10(9) M-circle dot, which are also the highest-EW galaxies. These findings suggest that the burstiness parameters of these strong emission-line galaxies may differ from those inferred from hydrodynamical simulations and previous observations. For instance, a larger burstiness duty cycle would explain the observed SFRH alpha excess. We also estimate the ionizing photon production efficiency xi(ion), finding a median value of log(xi(ion)/erg(-1) Hz) = 24.80 +/- 0.26 when adopting a Galactic dust correction for H alpha and an SMC one for the stellar component. We observe an increase of xi(ion) with redshift, further confirming similar results at higher redshifts. We also find that xi(ion) is strongly correlated with EWH alpha, which provides an approach for deriving xi(ion) in early galaxies. We observe that lower mass, lower luminosity galaxies have a higher xi(ion). Overall, these results provide further support for faint galaxies playing a major role in the reionization of the Universe.
AB - We investigate the burstiness of star formation and the ionizing efficiency of a large sample of galaxies at 0.7 < z < 1.5 using HST grism spectroscopy and deep ultraviolet (UV) imaging in the GOODS-N and GOODS-S fields. The star formation history (SFH) in these strong emission-line low-mass galaxies indicates an elevated star formation rate (SFR) based on the H alpha emission line at a given stellar mass when compared to the standard main sequence. Moreover, when comparing the H alpha and UV SFR indicators, we find that an excess in SFRH alpha compared to SFRUV is preferentially observed in lower mass galaxies below 10(9) M-circle dot, which are also the highest-EW galaxies. These findings suggest that the burstiness parameters of these strong emission-line galaxies may differ from those inferred from hydrodynamical simulations and previous observations. For instance, a larger burstiness duty cycle would explain the observed SFRH alpha excess. We also estimate the ionizing photon production efficiency xi(ion), finding a median value of log(xi(ion)/erg(-1) Hz) = 24.80 +/- 0.26 when adopting a Galactic dust correction for H alpha and an SMC one for the stellar component. We observe an increase of xi(ion) with redshift, further confirming similar results at higher redshifts. We also find that xi(ion) is strongly correlated with EWH alpha, which provides an approach for deriving xi(ion) in early galaxies. We observe that lower mass, lower luminosity galaxies have a higher xi(ion). Overall, these results provide further support for faint galaxies playing a major role in the reionization of the Universe.
KW - galaxies: dwarf
KW - galaxies: evolution
KW - galaxies: high-redshift
KW - cosmology: observations
KW - PHOTON PRODUCTION EFFICIENCY
KW - HUBBLE-SPACE-TELESCOPE
KW - SIMILAR-TO 2.5
KW - FORMING GALAXIES
KW - LYMAN-CONTINUUM
KW - COSMIC REIONIZATION
KW - DUST ATTENUATION
KW - NEBULAR EMISSION
KW - FORMATION RATES
KW - STELLAR MASS
U2 - 10.1093/mnras/stac360
DO - 10.1093/mnras/stac360
M3 - Journal article
VL - 511
SP - 4464
EP - 4479
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
SN - 0035-8711
IS - 3
ER -
ID: 303683661