ar X iv : a st ro - p h / 04 11 09 5 v 1 3 N ov 2 00 4 Carbon Stars and other Luminous Stellar Populations in M 33
نویسندگان
چکیده
The M33 galaxy is a nearby, relatively metal-poor, late-type spiral. Its proximity and almost face-on inclination means that it projects over a large area on the sky, making it an ideal candidate for wide-field CCD mosaic imaging. Photometry was obtained for more than 10 6 stars covering a 74 ′ × 56 ′ field centered on M33. Main sequence (MS), supergiant branch (SGB), red giant branch (RGB) and asymptotic giant branch (AGB) populations are identified and classified based on broad-band V and I photometry. Narrow-band filters are used to measure spectral features allowing the AGB population to be further divided into C and M-star types. The galactic structure of M33 is examined using star counts, colour-colour and colour-magnitude selected stellar populations. We use the C to M-star ratio to investigate the metallicity gradient in the disk of M33. The C/M-star ratio is found to increase and then flatten with increasing galactocentric radius in agreement with viscous disk formation models. The C-star luminosity function is found to be similar to M31 and the SMC, suggesting that C-stars should be useful distance indicators. The " spectacular arcs of carbon stars " in M33 postulated recently by Block et al. (2004) are found in our work to be simply an extension of M33's disk.
منابع مشابه
ar X iv : a st ro - p h / 04 11 30 1 v 1 1 1 N ov 2 00 4 K - LUMINOUS GALAXIES AT Z ∼ 2 Metallicity and B Stars
We present the results from the analysis of the composite spectrum of five near-IR luminous (K < 20) galaxies at z ∼ 2. Several of the strongest absorption lines are present in the merging galaxy NGC 6090 UV spectrum and are not present in the spectra of Lyman Break Galaxies at z ∼ 3. They were identified as SiIII 1296, CIII 1428, SiII 1485, and Fe ∼1380 Å which are photospheric lines typical o...
متن کاملar X iv : a st ro - p h / 06 11 03 3 v 1 1 N ov 2 00 6 On the Progenitor of Supernova 1987 A
A previously unpublished ultralow–dispersion spectrum of Sanduleak -69 202, the stellar progenitor of SN 1987A, is presented and the uncertain presupernova evolution of Sanduleak -69 202 is discussed. Subject headings: Supernovae: individual (SN 1987A) — techniques: ultralow– dispersion spectra — Large Magellanic Cloud — supergiants — stars: Sanduleak -69 202
متن کاملar X iv : a st ro - p h / 06 11 09 9 v 1 2 N ov 2 00 6 Nuclear Activity in UZC Compact Groups of Galaxies
متن کامل
ar X iv : a st ro - p h / 01 11 10 9 v 1 6 N ov 2 00 1 Big Bang Nucleosynthesis , Population III , and Stellar Genetics in the Galactic Halo ∗ Sean
The diverse isotopic and elemental signatures produced in different nucleosynthetic sites are passed on to successive generations of stars. By tracing these chemical signatures back through the stellar populations of the Galaxy, it is possible to unravel its nucleosynthetic history and even to study stars which are now extinct. This review considers recent applications of ”stellar genetics” to ...
متن کاملar X iv : a st ro - p h / 04 11 75 1 v 1 2 8 N ov 2 00 4 Where Are We Now , and Where Are We Going ? Perspectives on Cosmic Abundances
I was asked at the end of this (excellent!) conference to provide a few comments on the present status of the field of cosmic abundances, which I summarize (and extend upon) in this contribution. A discussion of the present " state of play " is given, along with some suggested directions for the future.
متن کامل