Stellar content of nearby galaxies. III - The local group spiral galaxy M33

1990 ◽  
Vol 99 ◽  
pp. 149 ◽  
Author(s):  
Christine D. Wilson ◽  
Barry F. Madore ◽  
Wendy L. Freedman
Keyword(s):  
Spiral Galaxy ◽  
Local Group ◽  
Stellar Content ◽  
Nearby Galaxies

scholarly journals Infrared, Optical, and X-ray Properties of the Nuclei of Nearby Galaxies

1978 ◽  
Vol 77 ◽  
pp. 227-236
Author(s):  
G. Burbidge
Keyword(s):  
Local Group ◽  
Galactic Center ◽  
Virgo Cluster ◽  
Physical Entity ◽  
Stellar Content ◽  
Nuclear Activity ◽  
X Ray ◽  
Show Evidence ◽  
Nearby Galaxies

The term “nearby galaxies” is not very precise. If we restrict ourselves to galaxies within the local group, we are really only talking about our Galaxy, M31 and M33. Since the Galactic Center has been reviewed extensively by Oort in Annual Reviews (1977), and I feel that there is nothing exceptional to say about the nuclei of M31 and M33 as far as phenomena other than their stellar content and central dynamics are concerned, to discuss interesting properties we must consider more distant objects. If we go out to the distance of the Virgo cluster, we already include objects such as NGC 5128, M82 and M87. Each of these galaxies shows or was claimed to show evidence of different kinds of violent nuclear activity. Indeed, it is obvious that within the volume occupied by the supercluster (whether or not it is really a physical entity) there must be many galaxies in which nuclear activity can be detected.

The Stellar Content of the Local Group Dwarf Galaxy Phoenix

1999 ◽  
Vol 118 (2) ◽  
pp. 862-882 ◽  
Author(s):  
D. Martínez-Delgado ◽  
C. Gallart ◽  
A. Aparicio
Keyword(s):  
Local Group ◽  
Dwarf Galaxy ◽  
Stellar Content

scholarly journals Wolf-Rayet stars at 1 - 2 Mpc

2003 ◽  
Vol 212 ◽  
pp. 547-548 ◽  
Author(s):  
Paul A. Crowther ◽  
Jay B. Abbott ◽  
Laurent Drissen ◽  
Hansrüdi Schild ◽  
Werner Schmutz ◽  
...  
Keyword(s):  
Optical Spectroscopy ◽  
Spiral Galaxy ◽  
Local Group ◽  
Narrow Band ◽  
Dwarf Galaxy ◽  
Narrow Band Imaging ◽  
Ic 10

We present new narrow-band imaging and optical spectroscopy of Wolf-Rayet stars in the Local Group dwarf galaxy IC 10 (Gemini-N- gmos) and Sculptor group spiral galaxy NGC 300 (VLT fors2).

scholarly journals The strange case of the peculiar spiral galaxy NGC 5474

2020 ◽  
Vol 634 ◽  
pp. A124 ◽  
Author(s):  
M. Bellazzini ◽  
F. Annibali ◽  
M. Tosi ◽  
A. Mucciarelli ◽  
M. Cignoni ◽  
...  
Keyword(s):  
Old Age ◽  
Spiral Galaxy ◽  
The Other ◽  
Spiral Pattern ◽  
Stellar Content ◽  
Peculiar Star ◽  
Space Telescope ◽  
Stellar Disc ◽  
Star Forming ◽  
The Galaxy

We present the first analysis of the stellar content of the structures and substructures identified in the peculiar star-forming galaxy NGC 5474, based on Hubble Space Telescope resolved photometry from the LEGUS survey. NGC 5474 is a satellite of the giant spiral M 101, and it is known to have a prominent bulge that is significantly off-set from the kinematic centre of the underlying H I and stellar disc. The youngest stars (age ≲ 100 Myr) trace a flocculent spiral pattern extending out to ≳8 kpc from the centre of the galaxy. On the other hand, intermediate-age (age ≳ 500 Myr) and old (age ≳ 2 Gyr) stars dominate the off-centred bulge and a large substructure residing in the south-western part of the disc (SW over-density) and they are not correlated with the spiral arms. The old age of the stars in the SW over-density suggests that this may be another signature of any dynamical interactions that have shaped this anomalous galaxy. We suggest that a fly by with M 101, generally invoked as the origin of the anomalies, may not be sufficient to explain all the observations. A more local and more recent interaction may help to put all the pieces of this galactic puzzle together.

scholarly journals What do planetary nebulae and H II regions reveal about the chemical evolution of nearby dwarf galaxies?

2018 ◽  
Vol 14 (S344) ◽  
pp. 161-177 ◽  
Author(s):  
Denise R. Gonçalves
Keyword(s):  
Chemical Evolution ◽  
Local Group ◽  
Planetary Nebulae ◽  
H Ii Regions ◽  
Chemical Abundances ◽  
Local Universe ◽  
Time Line ◽  
Nearby Galaxies ◽  
H Ii Region ◽  
Age Range

AbstractThe Local Group contains a great number of dwarf irregulars and spheroidals, for which the spectroscopy of individual stars can be obtained. Thus, the chemical evolution of these galaxies can be traced, with the only need of finding populations spanning a large age range and such that we can accurately derive the composition. Planetary nebulae (PNe) are old- and intermediate-age star remnants and their chemical abundances can be obtained up to 3-4 Mpc. H ii regions, which are brighter and much easily detected, represent galaxies young content. PNe and H ii regions share similar spectroscopic features and are analysed in the same way. Both are among the best tracers of the chemical evolution allowing to draw the chemical time line of nearby galaxies. The focus in this review are the PN and H ii region populations as constraints to the chemical evolution models and the mass-metallicity relation of the local universe.

scholarly journals The Motion of the Local Group of Galaxies with Respect to the Background of Galaxies

1983 ◽  
Vol 104 ◽  
pp. 255-258
Author(s):  
R. D. Davies
Keyword(s):  
Large Scale ◽  
Local Group ◽  
Microwave Background ◽  
Optical Studies ◽  
Group Motion ◽  
Gravitational Influence ◽  
Nearby Galaxies ◽  
Peculiar Motion ◽  
The Universe ◽  
Hubble Flow

A measurement of the motion of the Local Group of galaxies through the Universe provides an indication of their peculiar motion relative to the Hubble flow consequent upon the gravitational influence of the local large scale mass inhomogeneities. This motion can be measured either relative to the cosmic microwave background at z ∼ 1000 or relative to the background or nearby (z ∼ 0.01) galaxies. The interpretation of published measurements is subject to some uncertainty. As an example, the Local Group motion derived from optical studies of nearby galaxies (Rubin et al. 1976) differs from that derived from radio frequency measurements of the dipole anisotropy in the microwave background. (Boughn et al. 1981, Gorenstein & Smoot 1981).

scholarly journals Super star clusters in the Galactic Center as revealed by HST-NICMOS

1999 ◽  
Vol 193 ◽  
pp. 459-469
Author(s):  
Donald F. Figer ◽  
Sungsoo S. Kim ◽  
Mark Morris ◽  
Eugene Serabyn
Keyword(s):  
Main Sequence ◽  
Local Group ◽  
Galactic Center ◽  
Formation Rate ◽  
Star Clusters ◽  
Initial Mass Function ◽  
Stellar Content ◽  
Multiple Star ◽  
Super Star Clusters ◽  
Massive Clusters

The three massive clusters in the Galactic Center are not only the most massive young clusters in the Galaxy, but they harbor more Wolf-Rayet stars than any other starburst region in the Local Group. An understanding of their stellar content will be valuable for extending models to starburst regions in other galaxies. We present HST-NICMOS images, luminosity functions, and color-magnitude diagrams of two of these: the Quintuplet and Arches clusters. The images allow the detection of stars over 6 magnitudes fainter than ever before and reveal previously undetected multiple star systems. For the first time, we clearly identify the main sequence in the Quintuplet cluster, and we extend earlier detections of the main sequence in the Arches cluster to Minitial < 10 M⊙. We estimate that the Arches cluster has an initial mass function slope which is greater than the Salpeter value. Given their stellar content, the Galactic Center clusters provide both the best nearby examples of super star clusters and the best nearby locale in which to investigate WR phenomena in starburst galaxies and galactic nuclei. We discuss the content of the Galactic Center clusters, with a particular emphasis on how they compare to other massive clusters of the local group. We expect that many of the massive stars in the Galactic Center will soon evolve to become WR stars, and eventually become supernovae at a rate of ∼ 1 per 20 000 years for the next several Myr. We note that our preliminary N-body simulations suggest that such dense clusters are short-lived in the strong tidal field of the Galactic Center, consistent with the fact that no older dense clusters are seen in the central 50 pc. This implies a star formation rate of 5(10−3) M⊙ yr−1 in the Galactic Center.

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