Environmental Effects in Star-Forming Dwarf Galaxies

1994 ◽  
pp. 214-219
Author(s):  
J. M. Vilchez
Keyword(s):  
Environmental Effects ◽  
Dwarf Galaxies ◽  
Star Forming

scholarly journals Tidal Dwarf Galaxies

1998 ◽  
Vol 11 (1) ◽  
pp. 141-144
Author(s):  
P.-A. Duc ◽  
I.F. Mirabel ◽  
E. Brinks
Keyword(s):  
Environmental Effects ◽  
Intergalactic Medium ◽  
Dwarf Galaxies ◽  
Star Forming ◽  
Evolution Of Galaxies ◽  
New Generation

The life and evolution of galaxies are dramatically affected by environmental effects. Interactions with the intergalactic medium and collisions with companions cause major perturbations in the morphology and contents of galaxies: in particular stars and gas clouds may be gravitationally pulled out from their parent galaxies during tidal encounters, forming rings, tails and bridges. This debris of collisions lies at the origin of a new generation of small galaxies, the so-called “tidal dwarf galaxies” (hereafter TDGs). Such an exotic way of forming galaxies was put forward by Schweizer (1978) and by Mirabel et al. (1992), who clearly observed the genesis of a star-forming object, out of material tidally expelled from the interacting system NGC 4038/39 (“The Antennae”). Recent studies, based on optical and HI observations, have shown that TDGs actually form a class of “recycled” objects with some properties similar to the more classical dwarf irregulars (dIrr) and blue compact dwarf galaxies (BCDs).

scholarly journals The weak imprint of environment on the stellar populations of galaxies

2020 ◽  
Vol 500 (4) ◽  
pp. 4469-4490 ◽  
Author(s):  
James Trussler ◽  
Roberto Maiolino ◽  
Claudia Maraston ◽  
Yingjie Peng ◽  
Daniel Thomas ◽  
...  
Keyword(s):  
Environmental Effects ◽  
Unique Feature ◽  
Stellar Populations ◽  
Stellar Mass ◽  
Sloan Digital Sky Survey ◽  
Star Forming ◽  
Sky Survey ◽  
Satellite Galaxies ◽  
Projected Distance ◽  
Environmental Dependence

ABSTRACT We investigate the environmental dependence of the stellar populations of galaxies in Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Echoing earlier works, we find that satellites are both more metal-rich (<0.1 dex) and older (<2 Gyr) than centrals of the same stellar mass. However, after separating star-forming, green valley, and passive galaxies, we find that the true environmental dependence of both stellar metallicity (<0.03 dex) and age (<0.5 Gyr) is in fact much weaker. We show that the strong environmental effects found when galaxies are not differentiated result from a combination of selection effects brought about by the environmental dependence of the quenched fraction of galaxies, and thus we strongly advocate for the separation of star-forming, green valley, and passive galaxies when the environmental dependence of galaxy properties are investigated. We also study further environmental trends separately for both central and satellite galaxies. We find that star-forming galaxies show no environmental effects, neither for centrals nor for satellites. In contrast, the stellar metallicities of passive and green valley satellites increase weakly (<0.05 and <0.08 dex, respectively) with increasing halo mass, increasing local overdensity and decreasing projected distance from their central; this effect is interpreted in terms of moderate environmental starvation (‘strangulation’) contributing to the quenching of satellite galaxies. Finally, we find a unique feature in the stellar mass–stellar metallicity relation for passive centrals, where galaxies in more massive haloes have larger stellar mass (∼0.1 dex) at constant stellar metallicity; this effect is interpreted in terms of dry merging of passive central galaxies and/or progenitor bias.

scholarly journals The Violent Interstellar Medium of Nearby Dwarf Galaxies

1999 ◽  
Vol 16 (1) ◽  
pp. 106-112 ◽  
Author(s):  
Fabian Walter
Keyword(s):  
Interstellar Medium ◽  
Gamma Ray ◽  
Dwarf Galaxies ◽  
Young Star ◽  
Stellar Winds ◽  
Star Forming ◽  
Star Forming Regions ◽  
Supernova Explosions ◽  
High Velocity Clouds ◽  
Ob Associations

AbstractHigh resolution HI observations of nearby dwarf galaxies (most of which are situated in the M81 group at a distance of about 3·2 Mpc) reveal that their neutral interstellar medium (ISM) is dominated by hole-like features most of which are expanding. A comparison of the physical properties of these holes with the ones found in more massive spiral galaxies (such as M31 and M33) shows that they tend to reach much larger sizes in dwarf galaxies. This can be understood in terms of the galaxy's gravitational potential. The origin of these features is still a matter of debate. In general, young star forming regions (OB-associations) are held responsible for their formation. This picture, however, is not without its critics and other mechanisms such as the infall of high velocity clouds, turbulent motions or even gamma ray bursters have been recently proposed. Here I will present one example of a supergiant shell in IC 2574 which corroborates the picture that OB associations are indeed creating these structures. This particular supergiant shell is currently the most promising case to study the effects of the combined effects of stellar winds and supernova explosions which shape the neutral interstellar medium of (dwarf) galaxies.

scholarly journals On faint companions in the close environment of star-forming dwarf galaxies

2001 ◽  
Vol 371 (3) ◽  
pp. 806-815 ◽  
Author(s):  
K. G. Noeske ◽  
J. Iglesias-Páramo ◽  
J. M. Vílchez ◽  
P. Papaderos ◽  
K. J. Fricke
Keyword(s):  
Dwarf Galaxies ◽  
Star Forming

Sardinia Radio Telescope (SRT) observations of Local Group dwarf galaxies

2017 ◽  
Vol 13 (S336) ◽  
pp. 109-112
Author(s):  
A. Tarchi ◽  
P. Castangia ◽  
G. Surcis ◽  
A. Brunthaler ◽  
K. M. Menten ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Radio Continuum ◽  
Maser Emission ◽  
Star Forming ◽  
Star Forming Regions ◽  
First Results ◽  
Ngc 6822 ◽  
Almost All

AbstractThe dwarf galaxies in the Local Group (LG) reveal a surprising amount of spatial structuring. In particular, almost all non-satellite dwarfs belong to one of two planes that show a very pronounced symmetry. In order to determine if these structures in the LG are dynamically stable or, alternatively, if they only represent transient alignments, proper motion measurements of these galaxies are required. A viable method to derive proper motions is offered by VLBI studies of 22-GHz water (and 6.7-GHz methanol) maser lines in star-forming regions.In 2016, in the framework of the Early Science Program of the Sardinia Radio Telescope (SRT), we have conducted an extensive observational campaign to map the entire optical body of all the LG dwarf galaxies that belong to the two planes, at C and K band, in a search for methanol and water maser emission.Here, we outline the project and present its first results on 3 targets, NGC 6822, IC 1613, and WLM. While no luminous maser emission has been detected in these galaxies, a number of interesting weaker detections has been obtained, associated with particularly active star forming regions. In addition, we have produced deep radio continuum maps for these galaxies, aimed at investigating their star forming activity and providing an improved assessment of star formation rates in these galaxies.

scholarly journals Super Stellar Clusters in HII Galaxies

2002 ◽  
Vol 207 ◽  
pp. 357-366
Author(s):  
Eduardo Telles
Keyword(s):  
Dwarf Galaxies ◽  
Stellar Clusters ◽  
Star Forming

Stellar Clusters are identified in images and in the spectra of these star forming dwarf galaxies. These Stellar Clusters have properties similar to those observed in other violent star forming galaxies and may the elementary entities of a starburst.

A TREASURY STUDY OF STAR-FORMING REGIONS IN THE LOCAL GROUP. I.HSTPHOTOMETRY OF YOUNG POPULATIONS IN SIX DWARF GALAXIES

2012 ◽  
Vol 143 (3) ◽  
pp. 74 ◽  
Author(s):  
Luciana Bianchi ◽  
Boryana Efremova ◽  
Paul Hodge ◽  
Philip Massey ◽  
K. A. G. Olsen
Keyword(s):  
Local Group ◽  
Dwarf Galaxies ◽  
Star Forming ◽  
Star Forming Regions

scholarly journals Dust emission in star-forming dwarf galaxies: General properties and the nature of the submm excess

2014 ◽  
Vol 570 ◽  
pp. A97 ◽  
Author(s):  
Y. I. Izotov ◽  
N. G. Guseva ◽  
K. J. Fricke ◽  
E. Krügel ◽  
C. Henkel
Keyword(s):  
Dwarf Galaxies ◽  
Dust Emission ◽  
Star Forming ◽  
General Properties ◽  
Galaxies General
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