scholarly journals The Recent Star Formation Histories of M81 Group Dwarf Irregular Galaxies

2008 ◽  
Vol 689 (1) ◽  
pp. 160-183 ◽  
Author(s):  
Daniel R. Weisz ◽  
Evan D. Skillman ◽  
John M. Cannon ◽  
Andrew E. Dolphin ◽  
Robert C. Kennicutt, Jr. ◽  
...  
Keyword(s):  
Star Formation ◽  
Irregular Galaxies ◽  
Star Formation Histories ◽  
Dwarf Irregular Galaxies

scholarly journals A new method to derive star formation histories in dwarf galaxies

2018 ◽  
Vol 14 (S344) ◽  
pp. 267-270
Author(s):  
Marius Čeponis ◽  
Rima Stonkutė ◽  
Vladas Vansevičius
Keyword(s):  
Star Formation ◽  
New Method ◽  
Star Forming ◽  
Stellar Photometry ◽  
Star Forming Regions ◽  
Density Maps ◽  
Irregular Galaxies ◽  
Star Formation Histories ◽  
Dwarf Irregular Galaxies ◽  
Inside Out

AbstractWe present a new method to derive 2D star formation histories in dwarf irregular galaxies. Based on multicolor stellar photometry data we have found that in the Leo A galaxy during the last ∽400 Myr star formation was propagating according to the inside-out scenario. Star-forming regions have spread strongly asymmetrically from the center and their present day distribution correlates well with the Hi surface density maps.

scholarly journals Star formation histories in dwarf irregular galaxies in the Local Group

1991 ◽  
Vol 148 ◽  
pp. 343-344
Author(s):  
L. Greggio ◽  
G. Marconi ◽  
P. Focardi ◽  
M. Tosi
Keyword(s):  
Star Formation ◽  
Local Group ◽  
Mass Function ◽  
Initial Mass Function ◽  
Main Sequence Stars ◽  
Star Formation Activity ◽  
Irregular Galaxies ◽  
Ccd Observations ◽  
Star Formation Histories ◽  
Dwarf Irregular Galaxies

The process of star formation (SF) and the modalities with which it occurs in galaxies of different sizes are still poorly understood. On the other hand, interpretation of the chemical and photometric properties of galaxies requires the adoption of adequate laws for the SF rate and Initial Mass Function (IMF) in model computations. Dwarf irregular galaxies in the Local Group offer the chance to study their SF history through analysis of their HR diagrams, which can be derived down to V 25, corresponding to MV0, i.e. to main sequence stars of 2 M⊙. Therefore, for these galaxies, we can derive information on the star formation activity which has occurred over the last 1 Gyr approximately. In this framework, we have undertaken CCD observations of Dwarf irregular galaxies in the Local Group with ESO telescopes and briefly present here the results obtained for DDO 210, Sextans B and NGC 3109.

scholarly journals HI Distribution in Extreme Dwarf Irregulars and Dwarf Spheroidals

1998 ◽  
Vol 11 (1) ◽  
pp. 121-122
Author(s):  
Claude Carignan
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Large Fraction ◽  
Dwarf Spheroidal Galaxies ◽  
Irregular Galaxies ◽  
Single Burst ◽  
Dwarf Spheroidals ◽  
Dwarf Irregular Galaxies ◽  
Spheroidal Galaxies

Recent studies (Puche & Westpfahl 1994, Young & Lo 1996) have shown that the distribution of HI in some extreme low luminosity dwarf irregular galaxies (e.g. M81dwA, Holmberg I, Leo A) tends to have a ring-like (or shell-like) distribution which suggests that a single burst of star formation could expell most of the remaining ISM (or at least a large fraction of it) from the system. In view of this, Puche & Westpfahl (1994) suggested that in dwarf spheroidal galaxies, the HI should be found at large radii since no young stellar population is observed in most of them.

Stellar feedback in dwarf irregular galaxies with radio continuum observations

2018 ◽  
Vol 14 (S344) ◽  
pp. 255-258
Author(s):  
Volker Heesen ◽  
Aritra Basu ◽  
Elias Brinks ◽  
George Heald ◽  
Andrew Fletcher ◽  
...  
Keyword(s):  
Star Formation ◽  
Low Frequency ◽  
Cosmic Ray ◽  
Radio Continuum ◽  
Very Large Array ◽  
Radio Halo ◽  
Spatially Resolved ◽  
Ic 10 ◽  
Irregular Galaxies ◽  
Dwarf Irregular Galaxies

AbstractLow-mass dwarf irregular galaxies are subject to outflows, in which cosmic rays may play a very important role; they can be traced via their electron component, the cosmic ray electrons (CRe), in the radio continuum as non-thermal synchrotron emission. With the advent of sensitive low-frequency observations, such as with the Low-Frequency Array (LOFAR), we can trace CRe far away from star formation sites. Together with GHz-observations, such as with the Very Large Array (VLA), we can study spatially resolved radio continuum spectra at matched angular resolution and sensitivity. Here, we present results from our 6-GHz VLA survey of 40 nearby dwarf galaxies and our LOFAR study of the nearby starburst dwarf irregular galaxy IC 10. We explore the relation of RC emission with star formation tracers and study in IC 10 the nature of a low-frequency radio halo, which we find to be the result of a galactic wind.

Star formation in dwarf irregular galaxies - DDO 210 and NGC 3109

1993 ◽  
Vol 105 ◽  
pp. 894 ◽  
Author(s):  
L. Greggio ◽  
G. Marconi ◽  
M. Tosi ◽  
P. Focardi
Keyword(s):  
Star Formation ◽  
Irregular Galaxies ◽  
Dwarf Irregular Galaxies

scholarly journals Chemical abundances of massive stars in Local Group galaxies

2003 ◽  
Vol 212 ◽  
pp. 30-37 ◽  
Author(s):  
Kim A. Venn ◽  
Andreas Kaufer ◽  
Eline Tolstoy ◽  
Rolf-Peter Kudritzki ◽  
Norbert Przybilla ◽  
...  
Keyword(s):  
High Efficiency ◽  
Local Group ◽  
Iron Group ◽  
Chemical Abundances ◽  
Elemental Abundances ◽  
Irregular Galaxies ◽  
Ngc 6822 ◽  
Process Elements ◽  
Star Formation Histories ◽  
Dwarf Irregular Galaxies

The relative abundances of elements in galaxies can provide valuable information on the stellar and chemical evolution of a galaxy. While nebulae can provide abundances for a variety of light elements, stars are the only way to directly determine the abundances of iron-group and s-process and r-process elements in a galaxy. The new 8m and 10m class telescopes and high-efficiency spectrographs now make high-quality spectral observations of bright supergiants possible in dwarf galaxies in the Local Group. We have been concentrating on elemental abundances in the metal-poor dwarf irregular galaxies, NGC 6822, WLM, Sextants A, and GR 8. Comparing abundance ratios to those predicted from their star formation histories, determined from color-magnitude diagrams, and comparing those ratios between these galaxies can give us new insights into the evolution of these dwarf irregular galaxies. Iron-group abundances also allow us to examine the metallicities of the stars in these galaxies directly, which affects their inferred mass loss rates and predicted stellar evolution properties.

scholarly journals The relation between atomic gas and star formation rate densities in faint dwarf irregular galaxies

2014 ◽  
Vol 445 (2) ◽  
pp. 1392-1402 ◽  
Author(s):  
Sambit Roychowdhury ◽  
Jayaram N. Chengalur ◽  
Serafim S. Kaisin ◽  
Igor D. Karachentsev
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Irregular Galaxies ◽  
Atomic Gas ◽  
Dwarf Irregular Galaxies
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