منابع مشابه
The Star Formation Histories of the M31 and M33 Spheroids
I review the observational constraints on the star formation histories in the spheroids of M33 and M31, the other two spiral galaxies in the Local Group. M33 does not possess a traditional bulge; instead, it has a small nuclear region hosting stars with a wide range of ages. The star formation history of the M33 halo is poorly constrained, but composite spectra of its halo globular clusters imp...
متن کاملComparing Giant Molecular Clouds in M31, M33 & the Milky Way
We present new observations of a 2 field in the north-eastern spiral arm of M31. In the 0.8 × 3.6 kpc mosaicked region, we have detected six distinct, large complexes of molecular gas, most of which lie along the spiral arm dust lane or in the vicinity of HII regions. The mean properties of these complexes are as follows: D∼57±13 pc, ∆V∼ 6.5±1.2 km s, MCO∼3.0±1.6 ×10 5 M⊙, peak brightness tempe...
متن کاملExtended Hi Rotation Curve and Mass Distribution of M31
New HI observations of Messier 31 (M31) obtained with the Effelsberg and Green Bank 100-m telescopes make it possible to measure the rotation curve of that galaxy out to ∼ 35 kpc. Between 20 and 35 kpc, the rotation curve is nearly flat at a velocity of ∼ 226 km s−1 . A model of the mass distribution shows that at the last observed velocity point, the minimum dark–to–luminous mass ratio is ∼ 0....
متن کاملUnveiling Dark Matter with HI and Hα Data - Observational Problems
We present combined Hα+HI rotation curves for a sample of spiral galaxies. Most of the velocity profiles (spectra at single points) in these galaxies are asymmetric, preventing the use of standard methods like the first moment analysis and the single Gaussian fitting. We thus propose a method similar to the Envelope-Tracing method (Sofue & Rubin 2001) to analyse those profiles from which we obt...
متن کاملComparative Analysis of Molecular Clouds in M31, M33, and the Milky Way
We present BIMA observations of a 20 field in the northeastern spiral arm of M31. In this region we find six giant molecular clouds (GMCs) that have a mean diameter of 57 13 pc, a mean velocity width of 6:5 1:2 km s , and a mean molecular mass of 3:0 1:6 ð Þ ; 10 M . The peak brightness temperature of these clouds ranges from 1.6 to 4.2 K. We compare these clouds to clouds in M33 observed by Wi...
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ژورنال
عنوان ژورنال: Proceedings of the International Astronomical Union
سال: 2010
ISSN: 1743-9213,1743-9221
DOI: 10.1017/s1743921311022599