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Age and metallicity gradients in the Galactic Bulge : A differential study using HST/WFPC2 observations

Feltzing, Sofia LU orcid and Gilmore, Gerry (1999) In Astrophysics and Space Science 265(1-4). p.337-340
Abstract

We test for age and metallicity gradients in the Galactic Bulge between the two low extinction windows Baade's window (l = 1°.1 b = -4°.8) and Sagittarius-I (l = 1°.3 b = -2°.7). We derive a metallicity difference of ≤ 0.2 dex between BW and SGR-I window. This corresponds to a metallicity gradient of 1.3 dex kpc-1. This steep gradient is reconcilable with the existence of a short scale length inner component to the Bulge, most likely that prominent in the NIR, which perhaps forms a separate entity superimposed on the larger, optical Bulge. Through number counts in colour-magnitude diagram around the turnoff for several fields and clusters, extending over a range in galactic longitude we find no evidence for a significant... (More)

We test for age and metallicity gradients in the Galactic Bulge between the two low extinction windows Baade's window (l = 1°.1 b = -4°.8) and Sagittarius-I (l = 1°.3 b = -2°.7). We derive a metallicity difference of ≤ 0.2 dex between BW and SGR-I window. This corresponds to a metallicity gradient of 1.3 dex kpc-1. This steep gradient is reconcilable with the existence of a short scale length inner component to the Bulge, most likely that prominent in the NIR, which perhaps forms a separate entity superimposed on the larger, optical Bulge. Through number counts in colour-magnitude diagram around the turnoff for several fields and clusters, extending over a range in galactic longitude we find no evidence for a significant young stellar population in the Galactic Bulge. Previous suggestions of the existence of a significant young stellar population have most likely incorrectly identified the foreground disk stars.

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author
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publishing date
type
Contribution to journal
publication status
published
subject
in
Astrophysics and Space Science
volume
265
issue
1-4
pages
4 pages
publisher
Springer
external identifiers
  • scopus:0346553201
ISSN
0004-640X
DOI
10.1023/A:1002188616863
language
English
LU publication?
no
id
681d5c7b-bbdc-4183-83ea-32eb6bdb063e
date added to LUP
2021-02-15 13:57:49
date last changed
2022-03-18 23:25:41
@article{681d5c7b-bbdc-4183-83ea-32eb6bdb063e,
  abstract     = {{<p>We test for age and metallicity gradients in the Galactic Bulge between the two low extinction windows Baade's window (l = 1°.1 b = -4°.8) and Sagittarius-I (l = 1°.3 b = -2°.7). We derive a metallicity difference of ≤ 0.2 dex between BW and SGR-I window. This corresponds to a metallicity gradient of 1.3 dex kpc<sup>-1</sup>. This steep gradient is reconcilable with the existence of a short scale length inner component to the Bulge, most likely that prominent in the NIR, which perhaps forms a separate entity superimposed on the larger, optical Bulge. Through number counts in colour-magnitude diagram around the turnoff for several fields and clusters, extending over a range in galactic longitude we find no evidence for a significant young stellar population in the Galactic Bulge. Previous suggestions of the existence of a significant young stellar population have most likely incorrectly identified the foreground disk stars.</p>}},
  author       = {{Feltzing, Sofia and Gilmore, Gerry}},
  issn         = {{0004-640X}},
  language     = {{eng}},
  number       = {{1-4}},
  pages        = {{337--340}},
  publisher    = {{Springer}},
  series       = {{Astrophysics and Space Science}},
  title        = {{Age and metallicity gradients in the Galactic Bulge : A differential study using HST/WFPC2 observations}},
  url          = {{http://dx.doi.org/10.1023/A:1002188616863}},
  doi          = {{10.1023/A:1002188616863}},
  volume       = {{265}},
  year         = {{1999}},
}