The star formation histories of dwarf spheroidal galaxies

1997 ◽  
Author(s):  
Tammy A. Smecker-Hane
Keyword(s):  
Star Formation ◽  
Dwarf Spheroidal Galaxies ◽  
Star Formation Histories ◽  
Spheroidal Galaxies

The spatial segregation impact on the star formation histories of nearby dwarf spheroidal galaxies

2018 ◽  
Vol 14 (S344) ◽  
pp. 389-391
Author(s):  
Lidia Makarova ◽  
Dmitry Makarov
Keyword(s):  
Comparative Analysis ◽  
Star Formation ◽  
Middle Ages ◽  
Local Group ◽  
Stellar Populations ◽  
Spatial Segregation ◽  
Dwarf Spheroidal Galaxies ◽  
Zero Velocity ◽  
Star Formation Histories ◽  
Spheroidal Galaxies

AbstractUsing our HST/ACS observations of the recently found isolated dwarf spheroidal galaxies, we homogeneously measured their star formation histories (SFHs). We determined SF rate as a function of time, as well as age and metallicity of the stellar populations. All objects demonstrate complex SFH, with a significant portion of stars formed 10–13 Gyr ago. Nevertheless, stars of middle ages (1–8 Gyr) are presented. In order to understand how the SF parameters influence the evolution of dSphs, we also studied a sample of nearest dSphs in different environment: isolated (d < 2 Mpc); beyond the Local Group virial radius (but within the LG zero velocity sphere); and the satellites of M31 located within the virial zone (300 kpc). Using archival HST/ACS observations, we measured their SFHs. A comparative analysis of the parameters obtained give us a possibility to distinguish a possible effect of the spatial segregation on the dSphs evolution scenario.

scholarly journals A possible formation scenario for dwarf spheroidal galaxies – III. Adding star formation histories to the fiducial model

2017 ◽  
Vol 473 (4) ◽  
pp. 5015-5025 ◽  
Author(s):  
A. G. Alarcón Jara ◽  
M. Fellhauer ◽  
D. R. Matus Carrillo ◽  
P. Assmann ◽  
F. Urrutia Zapata ◽  
...  
Keyword(s):  
Star Formation ◽  
Dwarf Spheroidal Galaxies ◽  
Star Formation Histories ◽  
Spheroidal Galaxies

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.

scholarly journals Pushing back the limits: detailed properties of dwarf galaxies in a ΛCDM universe

2018 ◽  
Vol 616 ◽  
pp. A96 ◽  
Author(s):  
Yves Revaz ◽  
Pascale Jablonka
Keyword(s):  
Star Formation ◽  
Local Group ◽  
Dwarf Galaxies ◽  
Mass Scale ◽  
Dwarf Spheroidal Galaxies ◽  
The Galaxy ◽  
Dynamical Simulations ◽  
Ursa Minor ◽  
Stellar Properties ◽  
Star Formation Histories

We present the results of a set of high-resolution chemo-dynamical simulations of dwarf galaxies in a ΛCDM cosmology. Out of an original (3.4 Mpc/h)3 cosmological box, a sample of 27 systems are re-simulated from z = 70 to z = 0 using a zoom-in technique. Gas and stellar properties are confronted to the observations in the greatest details: in addition to the galaxy global properties, we investigated the model galaxy velocity dispersion profiles, half-light radii, star formation histories, stellar metallicity distributions, and [Mg/Fe] abundance ratios. The formation and sustainability of the metallicity gradients and kinematically distinct stellar populations are also tackled. We show how the properties of six Local Group dwarf galaxies, NGC 6622, Andromeda II, Sculptor, Sextans, Ursa Minor and Draco are reproduced, and how they pertain to three main galaxy build-up modes. Our results indicate that the interaction with a massive central galaxy could be needed for a handful of Local Group dwarf spheroidal galaxies only, the vast majority of the systems and their variety of star formation histories arising naturally from a ΛCDM framework. We find that models fitting well the local Group dwarf galaxies are embedded in dark haloes of mass between 5 × 108 to a few 109 M⊙, without any missing satellite problem. We confirm the failure of the abundance matching approach at the mass scale of dwarf galaxies. Some of the observed faint however gas-rich galaxies with residual star formation, such as Leo T and Leo P, remain challenging. They point out the need of a better understanding of the UV-background heating.

The Local Group Dwarf Spheroidal Galaxies: A Key to Building Blocks in the Universe

2005 ◽  
Vol 201 ◽  
pp. 469-470
Author(s):  
Hiroyuki. Hirashita ◽  
Naoyuki. Tamura ◽  
Tsutomu T. Takeuchi
Keyword(s):  
Star Formation ◽  
Local Group ◽  
Building Blocks ◽  
Star Formation History ◽  
High Mass ◽  
Dwarf Spheroidal Galaxies ◽  
The Hierarchical Structure ◽  
History Of ◽  
Low Mass ◽  
Spheroidal Galaxies

Recent studies have been revealing the properties of dwarf spheroidal galaxies (dSphs). Their low mass indicates that the dSphs may provide a clue to physical properties of the building blocks in the hierarchical structure formation. We select the Local Group dSphs as a sample. To obtain the information on the star formation history of dSphs, we investigate the relation between their metallicity and virial mass. According to our scenario, the star formation efficiency of the dSphs is low because of strong regulation. This is consistent with their high mass-to-light ratios. We also comment on the environmental effects on the dSphs.

Modeling Star Formation in Dwarf Spheroidal Galaxies: A Case for Extended Dark Matter Halos

2005 ◽  
Vol 624 (2) ◽  
pp. 726-741 ◽  
Author(s):  
Sergey Mashchenko ◽  
H. M. P. Couchman ◽  
Alison Sills
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Dark Matter Halos ◽  
Dwarf Spheroidal Galaxies ◽  
Spheroidal Galaxies

scholarly journals Spatial segregation impact on star formation in nearby dwarf spheroidal galaxies

2021 ◽  
Vol 502 (2) ◽  
pp. 1623-1632
Author(s):  
L N Makarova ◽  
D I Makarov
Keyword(s):  
Comparative Analysis ◽  
Star Formation ◽  
Middle Ages ◽  
Local Group ◽  
Hubble Space Telescope ◽  
Spatial Segregation ◽  
Dwarf Spheroidal Galaxies ◽  
M 31 ◽  
Advanced Camera For Surveys ◽  
Star Formation Histories

ABSTRACT Using our Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) observations of the recently found isolated dwarf spheroidal (dSph) galaxies, we homogeneously measured their star formation histories (SFHs). We determined SF rate as a function of time, as well as age and metallicity of the stellar populations. All objects demonstrate complex SFH, with a significant portion of stars formed 10–13 Gyr ago. Nevertheless, stars of middle ages (1–8 Gyr) are presented. In order to understand how the SF parameters influence the evolution of dSphs, we also studied a sample of nearest dSphs in different environment: isolated (d &lt; 2 Mpc); beyond the Local Group (LG) virial radius (but within the LG zero-velocity sphere); and the satellites of M 31 located within the virial zone (300 kpc). Using archival HST/ACS observations, we measured their SFHs. A comparative analysis of the parameters obtained allow us to distinguish a possible effect of the spatial segregation on the dSphs evolution scenario.

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