Science-advisor
REGISTER info/FAQ
Login
username
password
     
forgot password?
register here
 
Research articles
  search articles
  reviews guidelines
  reviews
  articles index
My Pages
my alerts
  my messages
  my reviews
  my favorites
 
 
Stat
Members: 3643
Articles: 2'488'730
Articles rated: 2609

29 March 2024
 
  » arxiv » astro-ph/9607167

 Article overview


The mv vs fe Calibration: I. HST Color-Magnitude Diagrams of 8 Globular Clusters in M 31
F. Fusi Pecci ; R. Buonanno ; C. Cacciari ; C.E. Corsi ; S.G. Djorgovski ; L. Federici ; F.R. Ferraro ; G. Parmeggiani ; R.M. Rich ;
Date 31 Jul 1996
Subject astro-ph
AbstractColor Magnitude Diagrams (CMDs) of individual stars in 8 Globular Clusters in M31 down to about 1 mag fainter (V$sim 26.5$) than the Horizontal Branch have been obtained with the Hubble Space Telescope. In particular, we observed G280 and G351 with the FOC (f/96+F430W, f/96+F480LP) while the WFPC2 (F555W,F814W) frames for G1,G58,G105,G108,G219+Bo468 were retrieved from the HST archive. The cluster metallicities -fe- range from -1.8 to -0.4. Coupled with sufficiently accurate (to $simpm0.1$ mag) measures of the mean brightness of the HB --vhb--, appropriate estimates of reddening for each cluster, and the adoption of a distance modulus to M31 of dmo = 24.43, this has allowed us to yield a direct calibration for the mean absolute magnitude of the HB at the instability strip --mv-- with varying fe: M_V^{HB} = (0.13 pm 0.07)fe + (0.95 pm 0.09), where the associated errors result from the adopted global errors in the measure and best fitting procedures. The slope of the derived relation is fully consistent with that predicted by the standard and canonical models ($sim0.15$) and obtained by various ground-based observations, while it is only marginally compatible with higher values ($sim0.30$), also obtained in the past. The zero-point, which is crucial to absolute age determinations, depends on the adopted distance to M31 and is moreover affected by an additional error due to the residual uncertainties in the hst photometric zero-points ($sim0.05$ mag, at least). If confirmed, such a calibration of the mv vs fe relationship would imply old absolute ages ($> 16$Gyr) for the oldest Galactic globulars and fairly small age spread among those having a constant magnitude difference between the Main-Sequence Turnoff and the HB.
Source arXiv, astro-ph/9607167
Services Forum | Review | PDF | Favorites   
 
Visitor rating: did you like this article? no 1   2   3   4   5   yes

No review found.
 Did you like this article?

This article or document is ...
important:
of broad interest:
readable:
new:
correct:
Global appreciation:

  Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.

browser claudebot






ScienXe.org
» my Online CV
» Free


News, job offers and information for researchers and scientists:
home  |  contact  |  terms of use  |  sitemap
Copyright © 2005-2024 - Scimetrica