scholarly journals Statistics and properties of emission-line regions in the local volume dwarf galaxies

2020 ◽  
Vol 495 (4) ◽  
pp. 3592-3601
Author(s):  
I D Karachentsev ◽  
S S Kaisin
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Supernova Remnants ◽  
Dwarf Galaxies ◽  
Star Formation History ◽  
H Ii Regions ◽  
Late Type ◽  
Formation History ◽  
History Of ◽  
Hydrogen Mass

ABSTRACT We used the H α images  from a large sample of nearby late-type dwarf galaxies to investigate properties of their emission structure. The sample consists of 300 galaxies of the irregular (Irr), Magellanic irregular (Im), blue compact dwarf (BCD), and transition (Tr) types situated within a distance of 11 Mpc. In each galaxy, we indicated the number of compact H ii regions, the presence of bubble-like or filament-like structures, the presence of a faint diffuse emission, and a sign of the global burst. The larger the luminosity of a galaxy, the greater number of compact H ii sources in it. The integral and specific star formation rates (SFRs) of the dwarf increase steeply with the increase of the number of H ii regions showing the evidence of the epidemic character of the star formation process. The dwarf galaxies with emission-line bubbles, or filaments, or signs of the global star formation burst have approximately the same hydrogen-mass-to-luminosity ratio as that of the whole sample objects. However, their mean SFR is significantly higher than that of other galaxies in the sample. Emission bubble-like structures are found in the nearby dwarfs with a frequency of one case per four to five galaxies. Their linear diameters are close to those expected for supernova remnants. The mean specific SFR for the nearby late-type dwarfs is close to the Hubble parameter, H0 = −10.14 dex (yr)−1, consistent with the sluggish cosmic star formation history of galaxies of this kind.

scholarly journals Star Formation History of Nearby Dwarf Galaxies

1983 ◽  
Vol 6 ◽  
pp. 179-186
Author(s):  
J. R. Mould
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Star Formation History ◽  
Stellar Systems ◽  
Amount Of Information ◽  
Formation History ◽  
History Of

This review will take the linear view of the history of stellar systems. Thus the last billion years of a dwarf galaxy’s development receives no special attention. A considerable amount of information has recently come to light on the intermediate age populations of dwarf galaxies.

scholarly journals HUBBLE SPACE TELESCOPEGRISM SPECTROSCOPY OF EXTREME STARBURSTS ACROSS COSMIC TIME: THE ROLE OF DWARF GALAXIES IN THE STAR FORMATION HISTORY OF THE UNIVERSE

2014 ◽  
Vol 789 (2) ◽  
pp. 96 ◽  
Author(s):  
Hakim Atek ◽  
Jean-Paul Kneib ◽  
Camilla Pacifici ◽  
Matthew Malkan ◽  
Stephane Charlot ◽  
...  
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Cosmic Time ◽  
Star Formation History ◽  
Formation History ◽  
History Of ◽  
The Universe

scholarly journals Dwarf Galaxies: From the Epoch of Peak Star Formation to the Epoch of Reionization

2018 ◽  
Vol 14 (S344) ◽  
pp. 429-436
Author(s):  
Hakim Atek
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
High Redshift ◽  
Great Part ◽  
Star Formation History ◽  
Dark Matter Halos ◽  
Galaxy Surveys ◽  
Formation History ◽  
History Of ◽  
Low Mass

AbstractDwarf galaxies represent the dominant population at high redshift and they most likely contributed in great part to star formation history of the Universe and cosmic reionization. The importance of dwarf galaxies at high redshift has been mostly recognized in the last decade due to large progress in observing facilities allowing deep galaxy surveys to identify low-mass galaxies. This population appear to have extreme emission lines and ionizing properties that challenge stellar population models. Star formation follows a stochastic process in these galaxies, which has important implication on the ionizing photon production and its escape fraction whose measurements are challenging for both simulations and observations. Outstanding questions include: what are the physical properties at the origin of such extreme properties? What are the smallest dark matter halos that host star formation? Are dwarf galaxies responsible for cosmic reionization?

scholarly journals THE ACS LCID PROJECT. IX. IMPRINTS OF THE EARLY UNIVERSE IN THE RADIAL VARIATION OF THE STAR FORMATION HISTORY OF DWARF GALAXIES

2013 ◽  
Vol 778 (2) ◽  
pp. 103 ◽  
Author(s):  
Sebastian L. Hidalgo ◽  
Matteo Monelli ◽  
Antonio Aparicio ◽  
Carme Gallart ◽  
Evan D. Skillman ◽  
...  
Keyword(s):  
Star Formation ◽  
Early Universe ◽  
Dwarf Galaxies ◽  
Radial Variation ◽  
Star Formation History ◽  
Formation History ◽  
History Of

scholarly journals The size-density relation of H ii regions in blue compact dwarf galaxies

2008 ◽  
Vol 4 (S255) ◽  
pp. 361-365
Author(s):  
Hiroyuki Hirashita ◽  
Leslie K. Hunt
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Star Formation History ◽  
H Ii Regions ◽  
Scale Free ◽  
Dust Extinction ◽  
Star Formation Activity ◽  
Formation History ◽  
Density Relation ◽  
Low Metallicity

AbstractWe investigate the size-density relation of H ii regions in blue compact dwarf galaxies (BCDs) by compiling observational data of their size (Di) and electron density (ne). We find that the size-density relation follows a relation with constant column density (ne ∝ Di−1) rather than with constant luminosity (ne ∝ Di−1.5). Such behavior resembles that of Galactic H ii regions, and may imply an underlying “scale-free” connection. Because this size-density relation cannot be explained by static models, we model and examine the evolution of the size-density relation of H ii regions by considering the star formation history and pressure-driven expansion of H ii regions. We find that the size-density relation of the entire BCD sample does not result from an evolutionary sequence of H ii regions but rather reflects a sequence with different initial gas densities (or “hierarchy” of density). We also find that the dust extinction of ionizing photons is significant for the BCD sample, despite their blue optical colors. This means that as long as the emission from H ii regions is used to trace massive star formation, we would miss the star formation activity in dense environments even in low-metallicity galaxies such as BCDs.

scholarly journals The Star Formation History of Eridanus II: On the Role of Supernova Feedback in the Quenching of Ultrafaint Dwarf Galaxies*

2021 ◽  
Vol 909 (2) ◽  
pp. 192 ◽  
Author(s):  
C. Gallart ◽  
M. Monelli ◽  
T. Ruiz-Lara ◽  
A. Calamida ◽  
S. Cassisi ◽  
...  
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Star Formation History ◽  
Formation History ◽  
History Of ◽  
Supernova Feedback
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