scholarly journals Recent Star Formation History of the Magellanic Clouds

1999 ◽  
Vol 190 ◽  
pp. 470-472
Author(s):  
Eva K. Grebel ◽  
Wolfgang Brandner

A new age calibration of Cepheids and supergiants is used to study the large-scale recent star formation history of the LMC and the SMC. We find evidence for migration of star formation along the LMC bar as well as for the existence of long-lived (≈ 200 Myr) extended star-forming features.

2011 ◽  
Vol 2011 ◽  
pp. 1-18 ◽  
Author(s):  
James Schombert ◽  
Tamela Maciel ◽  
Stacy McGaugh

This paper presents optical and Hαimaging for a large sample of LSB galaxies selected from the PSS-II catalogs (Schombert et al., 1992). As noted in previous work, LSB galaxies span a range of luminosities () and sizes (), although they are consistent in their irregular morphology. Their Hαluminosities (L(Hα)) range from 1036to 1041 ergs s−1(corresponding to a range in star formation, using canonical prescriptions, from 10−5to 1  yr−1). Although their optical colors are at the extreme blue edge for galaxies, they are similar to the colors of dwarf galaxies (Van Zee, 2001) and gas-rich irregulars (Hunter and Elmegreen, 2006). However, their star formation rates per unit stellar mass are a factor of ten less than other galaxies of the same baryonic mass, indicating that they are not simply quiescent versions of more active star-forming galaxies. This paper presents the data, reduction techniques, and new philosophy of data storage and presentation. Later papers in this series will explore the stellar population and star formation history of LSB galaxies using this dataset.


1999 ◽  
Vol 190 ◽  
pp. 464-465
Author(s):  
Paolo Battinelli ◽  
Serge Demers

Recently, Demers & Battinelli (1998) have shown that the young intercloud stellar aggregates are 10 to 25 Myr old, thus younger than the estimated age (200 Myr) of the last close LMC–SMC encounter (see, e.g., Irwin et al. 1996). These stellar aggregates show a distance gradient that confirms the existence of a “link” between the two Magellanic Clouds. Numerous blue stars have been detected by Demers & Irwin (1991) east of the aggregate ICA76 (the closest to the LMC). These blue stars, that extend to the southwestern periphery of the LMC, may be an aftermath of the close LMC–SMC encounter. Our present study is aimed to survey this SW part of the LMC and to determine the origin of these blue stars.


2011 ◽  
Vol 48 ◽  
pp. 43-49 ◽  
Author(s):  
M. Monelli ◽  
R. Carrera ◽  
C. Gallart ◽  
I. Meschin ◽  
A. Aparicio ◽  
...  

2008 ◽  
Vol 25 (3) ◽  
pp. 116-120 ◽  
Author(s):  
Jason Harris ◽  
Dennis Zaritsky

AbstractWe present a detailed reconstruction of the star-formation history of the Constellation III region in the Large Magellanic Cloud, to constrain the formation mechanism of this enigmatic feature. Star formation in Constellation III seems to have taken place during two distinct epochs: there is the 8–15 Myr epoch that had previously been recognized, but we also see strong evidence for a separate ‘burst’ of star formation 25–30 Myr ago. The ‘super-supernova' or GRB blast wave model for the formation of Constellation III is difficult to reconcile with such an extended, two-epoch star formation history, because the shock wave should have induced star formation throughout the structure simultaneously, and any unconsumed gas would quickly be dissipated, leaving nothing from which to form a subsequent burst of activity. We propose a ‘truly stochastic’ self-propagating star formation model, distinct from the canonical model in which star formation proceeds in a radially directed wave from the center of Constellation III to its perimeter. As others have noted, and we now confirm, the bulk age gradients demanded by such a model are simply not present in Constellation III. In our scenario, the prestellar gas is somehow pushed into these large-scale arc structures, without simultaneously triggering immediate and violent star formation throughout the structure. Rather, star formation proceeds in the arc according to the local physical conditions of the gas. Self-propagating star formation is certainly possible, but in a truly stochastic manner, without a directed, large scale pattern.


2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Kentaro Nagamine

We examine the past and current work on the star formation (SF) histories of dwarf galaxies in cosmological hydrodynamic simulations. The results obtained from different numerical methods are still somewhat mixed, but the differences are understandable if we consider the numerical and resolution effects. It remains a challenge to simulate the episodic nature of SF history in dwarf galaxies at late times within the cosmological context of a cold dark matter model. More work is needed to solve the mysteries of SF history of dwarf galaxies employing large-scale hydrodynamic simulations on the next generation of supercomputers.


1984 ◽  
Vol 108 ◽  
pp. 79-87
Author(s):  
L. L. Stryker

One of the most fundamental questions we might ask about galaxies is, Do all galaxies have the same age? A less general question, and one which we can surely succeed in answering is, Are the Magellanic Clouds (MCs) the same age as the Galaxy? We must also make clear what is meant by the same age if, in fact, star forming activities in these systems have proceeded along different timescales. The age of a system can be masked if the strongest star-forming epoch was not coincident with the initial epoch. Deep colour-magnitude diagrams (CMDs) and luminosity functions (LFs) have had to wait until the advent of large southern telescopes, sensitive emulsions and detectors, and accurate methods of measuring crowded images.


2008 ◽  
Vol 4 (S258) ◽  
pp. 51-60
Author(s):  
Carme Gallart ◽  
Ingrid Meschin ◽  
Noelia E. D. Noël ◽  
Antonio Aparicio ◽  
Sebastián L. Hidalgo ◽  
...  

AbstractThe star formation history of the Magellanic Clouds, including the old and intermediate-age star formation events, can be studied reliably and in detail through color-magnitude diagrams reaching the oldest main sequence turnoffs. This paper reviews our current understanding of the Magellanic Clouds' star formation histories and discusses the impact of this information on general studies of galaxy formation and evolution.


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