A Dwarf Irregular Galaxy at the Edge of the Local Group: Stellar Populations and Distance of IC 5152

1999 ◽  
Vol 117 (4) ◽  
pp. 1743-1757 ◽  
Author(s):  
Albert A. Zijlstra ◽  
Dante Minniti
Keyword(s):  
Local Group ◽  
Stellar Populations ◽  
Irregular Galaxy

scholarly journals Planetary nebulae as tracers of the kinematic structure of the starburst galaxy IC 10

2011 ◽  
Vol 7 (S283) ◽  
pp. 368-369
Author(s):  
Denise R. Gonçalves ◽  
Ana M. Teodorescu ◽  
Alan Alves-Brito ◽  
Roberto H. Méndez ◽  
Laura Magrini
Keyword(s):  
Star Formation ◽  
Kinematic Analysis ◽  
Local Group ◽  
Stellar Populations ◽  
Starburst Galaxy ◽  
Kinematic Structure ◽  
Irregular Galaxy ◽  
Tidal Interactions ◽  
Ic 10 ◽  
The Galaxy

AbstractThe Local Group dwarf irregular galaxy IC 10 is the nearest starburst galaxy (at 725 kpc) and presents extended and complex HI kinematics. It is believed that IC 10 is still experiencing an intense and very recent burst of star formation, likely triggered by infalling gas from an extended envelope which is counter-rotating with respect to the galaxy proper rotation. In this contribution we summarize our preliminary results (Gonçalves et al. 2011, in prep.) obtained by performing a kinematic analysis of the PN population of IC 10. Our aim is to explore the kinematic connection of its intermediate to old stellar populations with that obtained from HI observations. Some PNe were found at large galactocentric distances and could therefore represent a trace of past tidal interactions.

scholarly journals Star clusters in the dwarf irregular galaxy Leo A

2019 ◽  
Vol 627 ◽  
pp. A7
Author(s):  
R. Stonkutė ◽  
R. Naujalis ◽  
M. Čeponis ◽  
A. Leščinskaitė ◽  
V. Vansevičius
Keyword(s):  
Local Group ◽  
Spatial Clustering ◽  
Star Clusters ◽  
Stellar Populations ◽  
Stellar Mass ◽  
Star Cluster ◽  
Young Age ◽  
The Other ◽  
Irregular Galaxy ◽  
Low Mass

Context. Leo A is an isolated gas-rich dwarf irregular galaxy of low stellar mass and metallicity residing at the outskirts of the Local Group. Ages of the stellar populations in Leo A range from ∼10 Myr to ∼10 Gyr. So far, only one star cluster has been discovered in this galaxy. Aims. Our aim is to search for star cluster candidates in the Leo A galaxy. Methods. We performed photometry of star-like objects on HST ACS archive observation frames in the F475W and F814W passbands and studied the spatial clustering of the Leo A stars down to the turn-off point of the old stellar populations. Results. We report the discovery of four star clusters in the Leo A galaxy. This means that now a sample of five star clusters is known in Leo A. Two clusters are of a young age (∼20 Myr; overlapping with H II regions) and low in mass (≳400 M⊙ and ≳150 M⊙), the other three clusters are older (≳100 Myr) and also of low mass (≳300 M⊙). These rough estimates are made assuming the isochrones of a metallicity derived for H II regions (Z = 0.0007). Colour–magnitude diagrams of the stars residing in the circular areas of a 2.5″ radius around the clusters and integrated aperture photometry results of the clusters are presented.

The Stellar Populations of NGC 3109: Another Dwarf Irregular Galaxy with a Population II Stellar Halo

1999 ◽  
Vol 117 (2) ◽  
pp. 881-893 ◽  
Author(s):  
Dante Minniti ◽  
Albert A. Zijlstra, ◽  
M. Victoria Alonso
Keyword(s):  
Stellar Populations ◽  
Irregular Galaxy ◽  
Stellar Halo

scholarly journals Extragalactic GCs in the near-infrared: genuinely old in E/S0's?

2009 ◽  
Vol 5 (S262) ◽  
pp. 315-316
Author(s):  
Ana L. Chies-Santos ◽  
Søren S. Larsen
Keyword(s):  
Globular Cluster ◽  
Stellar Population ◽  
Near Infrared ◽  
Local Group ◽  
Stellar Populations ◽  
Age Dating ◽  
Early Type ◽  
Optical Photometry ◽  
Star Forming ◽  
Optical Images

Globular cluster (GC) systems are powerful probes to study the evolutionary histories of galaxies, being tracers of major star fomation episodes (Brodie & Strader 2006). They are found around all major galaxies and are easy to see far beyond the local group. Age dating GCs therefore helps pinpoint epochs of major star forming events. Spectroscopic age dating though (Strader et al. 2005) is extremely time consuming and can only access the few brightest clusters. An alternative is to combine near-infrared (NIR) and optical photometry, and therefore have a better chance in lifting the age metallicity degeneracy than with optical colours alone. This approach relies in testing GC colours against simple stellar population (SSP) models. The first studies following this technique showed the possible existence of a high percentage of intermediate age (2-3 Gyrs) GCs in early-type galaxies known to contain old stellar populations from integrated light studies. Two strong cases can be listed: NGC 4365 (Puzia et al. 2002, Larsen et al. 2005) and NGC 5846 (Hempel et al. 2003). In the present study we combine NIR deep photometry obtained with the WHT/LIRIS instrument and archival HST/ACS optical images to determine g(F475W), z(F840LP) and K(2.2m) magnitudes and colours of GCs in 14 early-type galaxies.

scholarly journals A High-Resolution Study of the HiContent of Local Group Dwarf Irregular Galaxy WLM

2007 ◽  
Vol 133 (5) ◽  
pp. 2242-2257 ◽  
Author(s):  
Amanda A. Kepley ◽  
Eric M. Wilcots ◽  
Deidre A. Hunter ◽  
Tyler Nordgren
Keyword(s):  
High Resolution ◽  
Local Group ◽  
Irregular Galaxy ◽  
Resolution Study

Discovery of Latent Star Formation in the Extended H i Gas around the Local Group Dwarf Irregular Galaxy NGC 6822

2003 ◽  
Vol 590 (1) ◽  
pp. L17-L20 ◽  
Author(s):  
Yutaka Komiyama ◽  
Sadanori Okamura ◽  
Masafumi Yagi ◽  
Hisanori Furusawa ◽  
Mamoru Doi ◽  
...  
Keyword(s):  
Star Formation ◽  
Local Group ◽  
Irregular Galaxy ◽  
Ngc 6822

scholarly journals Planetary Nebulae in Local Group Galaxies

1983 ◽  
Vol 103 ◽  
pp. 443-460
Author(s):  
Holland C. Ford
Keyword(s):  
Local Group ◽  
Planetary Nebulae ◽  
Stellar Populations ◽  
Chemical Compositions ◽  
H Ii Regions ◽  
Helium Abundance ◽  
Abundance Gradient ◽  
Star Forming ◽  
Ic 10 ◽  
Ngc 6822

Recent surveys for planetary nebulae have given the first identifications in Fornax, NGC 6822, M33, IC 10, Leo A, Sextans A, Pegasus, WLM, NGC 404, and M81, and extended the identifications in the SMC, the LMC, and M31. Observations of planetaries have established chemical compositions in old or intermediate age populations in 8 Local Group galaxies. The chemical compositions show that i) the helium abundance is higher in planetary nebulae than in H II regions in the same galaxy, and ii) nitrogen is overabundant relative to H II regions by factors of 4 to 100. Planetary nebulae are not a major source of helium in star-forming galaxies, and are a major source of nitrogen. The planetary in Fornax has a relatively high O abundance, and, together with Fornax's carbon stars, establishes the presence of at least 2 stellar populations. The abundance gradient derived from 3 planetaries in M31 is very shallow, and gives high abundances at ~ 20 kpc. By using planetary nebulae as standard candles, upper and lower distance limits have been set for 10 Local Group candidates, and a new distance estimated for M81.

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