scholarly journals The star formation histories of two Wolf-Rayet galaxies: NGC 1741 and He2-10. Two butterflies in a collection

1999 ◽  
Vol 193 ◽  
pp. 517-522
Author(s):  
Kelsey E. Johnson

In an effort to better understand how the properties of star formation in starburst galaxies depend on various environmental parameters, I present a comparison between two well-known WR galaxies: the interacting galaxy system NGC 1741 in the Hickson Compact Group 31, and the dwarf galaxy He2-10. The high spatial resolution of HST has allowed identification of a large number of starburst knots, or ‘super star clusters’ in these WR galaxies. Broad-band photometry and the latest stellar synthesis models are used to estimate the ages and masses of the super star clusters. The properties of the clusters are then used to compare and contrast the overall star-formation histories in the two WR galaxies.

2004 ◽  
Vol 221 ◽  
pp. 125-130
Author(s):  
Jean L. Turner ◽  
Sara C. Beck

Subarcsecond infrared and radio observations yield important information about the formation of super star clusters from their surrounding gas. We discuss the general properties of ionized and molecular gas near young, forming SSCs, as illustrated by the prototypical young, forming super star cluster nebula in the dwarf galaxy NGC 5253. This super star cluster appears to have a gravitationally bound nebula, and the lack of molecular gas suggests a very high star formation efficiency, consistent with the formation of a large, bound cluster.


2017 ◽  
Vol 842 (1) ◽  
pp. 47 ◽  
Author(s):  
E. Vanzella ◽  
M. Castellano ◽  
M. Meneghetti ◽  
A. Mercurio ◽  
G. B. Caminha ◽  
...  

2002 ◽  
Vol 207 ◽  
pp. 471-473
Author(s):  
Andrea M. Gilbert ◽  
James R. Graham

We summarize recent results from our study of the massive young super star clusters (SSCs) in the dwarf galaxy NGC 1569, and present new high-resolution NIRSPEC spectra that permit the measurement of a cluster's intrinsic stellar velocity dispersion. Thus we derive kinematic masses for the two brightest SSCs: 2.3 × 105 Msun for SSC B, and 3.9 × 105 and 4.4 × 105 Msun for the two components of SSC A.


2006 ◽  
Vol 2 (S237) ◽  
pp. 323-330 ◽  
Author(s):  
Pierre-Alain Duc ◽  
Frédéric Bournaud ◽  
Médéric Boquien

AbstractStar formation may take place in a variety of locations in interacting systems: in the dense core of mergers, in the shock regions at the interface of the colliding galaxies and even within the tidal debris expelled into the intergalactic medium. Along tidal tails, objects may be formed with masses ranging from those of super-star clusters to dwarf galaxies: the so-called Tidal Dwarf Galaxies (TDGs). Based on a set of multi-wavelength observations and extensive numerical simulations, we show how TDGs may simultaneously be used as laboratories to study the process of star-formation (SFE, IMF) in a specific environment and as probes of various cosmological properties, such as the distribution of dark matter and satellites around galaxies.


2008 ◽  
Vol 4 (S254) ◽  
pp. 209-220
Author(s):  
Pavel Kroupa

AbstractStars form in embedded star clusters which play a key role in determining the properties of a galaxy's stellar population. A large fraction of newly born massive stars are shot out from dynamically unstable embedded-cluster cores spreading them to large distances before they explode. Embedded clusters blow out their gas once the feedback energy from the new stellar population overcomes its binding energy, leading to cluster expansion and in many cases dissolution into the galaxy. Galactic disks may be thickened by such processes, and some thick disks may be the result of an early epoch of vigorous star-formation. Binary stellar systems are disrupted in clusters leading to a lower fraction of binaries in the field, while long-lived clusters harden degenerate-stellar binaries such that the SNIa rate may increase by orders of magnitude in those galaxies that were able to form long-lived clusters. The stellar initial mass function of the whole galaxy must be computed by adding the IMFs in the individual clusters. The resulting integrated galactic initial mass function (IGIMF) is top-light for SFRs < 10 M⊙/yr, and its slope and, more importantly, its upper stellar mass limit depend on the star-formation rate (SFR), explaining naturally the mass–metallicity relation of galaxies. Based on the IGIMF theory, the re-calibrated Hα-luminosity–SFR relation implies dwarf irregular galaxies to have the same gas-depletion time-scale as major disk galaxies, implying a major change of our concept of dwarf-galaxy evolution. A galaxy transforms about 0.3 per cent of its neutral gas mass every 10 Myr into stars. The IGIMF-theory also naturally leads to the observed radial Hα cutoff in disk galaxies without a radial star-formation cutoff. It emerges that the thorough understanding of the physics and distribution of star clusters may be leading to a major paradigm shift in our understanding of galaxy evolution.


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