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Title: HST/ACS OBSERVATIONS OF RR LYRAE STARS IN SIX ULTRA-DEEP FIELDS OF M31

Abstract

We present HST/ACS observations of RR Lyrae variable stars in six ultra-deep fields of the Andromeda galaxy (M31), including parts of the halo, disk, and giant stellar stream. Past work on the RR Lyrae stars in M31 has focused on various aspects of the stellar populations that make up the galaxy's halo, including their distances and metallicities. This study builds upon this previous work by increasing the spatial coverage (something that has been lacking in previous studies) and by searching for these variable stars in constituents of the galaxy not yet explored. Besides the 55 RR Lyrae stars we found in our initial field located 11 kpc from the galactic nucleus, we find additional RR Lyrae stars in four of the remaining five ultra-deep fields as follows: 21 in the disk, 24 in the giant stellar stream, three in the halo field 21 kpc from the galactic nucleus, and five in one of the halo fields at 35 kpc. No RR Lyrae stars were found in the second halo field at 35 kpc. The RR Lyrae populations of these fields appear to be mostly of Oosterhoff I type, although the 11 kpc field appears to be intermediate or mixed. Wemore » will discuss the properties of these stars including period and reddening distributions. We calculate metallicities and distances for the stars in each of these fields using different methods and compare the results, to an extent that has not yet been done. We compare these methods not just on RR Lyrae stars in our M31 fields, but also on a data set of Milky Way field RR Lyrae stars.« less

Authors:
; ; ; ;  [1];  [2];  [3];  [4]
  1. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  2. NASA/Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771 (United States)
  3. UCO/Lick Observatory, University of California Santa Cruz, Santa Cruz, CA 95064 (United States)
  4. Osservatorio Astronomico, Vicolo Dell'Osservatorio 5, I-35122, Padova (Italy)
Publication Date:
OSTI Identifier:
21583128
Resource Type:
Journal Article
Journal Name:
Astronomical Journal (New York, N.Y. Online)
Additional Journal Information:
Journal Volume: 141; Journal Issue: 5; Other Information: DOI: 10.1088/0004-6256/141/5/171; Journal ID: ISSN 1538-3881
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; GALACTIC EVOLUTION; GALAXIES; MILKY WAY; VARIABLE STARS; EVALUATION; EVOLUTION; STARS

Citation Formats

Jeffery, E J, Smith, E, Brown, T M, Kalirai, J S, Ferguson, H C, Sweigart, A V, Guhathakurta, P, Renzini, A, and Rich, R. M., E-mail: jeffery@stsci.edu. HST/ACS OBSERVATIONS OF RR LYRAE STARS IN SIX ULTRA-DEEP FIELDS OF M31. United States: N. p., 2011. Web. doi:10.1088/0004-6256/141/5/171.
Jeffery, E J, Smith, E, Brown, T M, Kalirai, J S, Ferguson, H C, Sweigart, A V, Guhathakurta, P, Renzini, A, & Rich, R. M., E-mail: jeffery@stsci.edu. HST/ACS OBSERVATIONS OF RR LYRAE STARS IN SIX ULTRA-DEEP FIELDS OF M31. United States. https://doi.org/10.1088/0004-6256/141/5/171
Jeffery, E J, Smith, E, Brown, T M, Kalirai, J S, Ferguson, H C, Sweigart, A V, Guhathakurta, P, Renzini, A, and Rich, R. M., E-mail: jeffery@stsci.edu. 2011. "HST/ACS OBSERVATIONS OF RR LYRAE STARS IN SIX ULTRA-DEEP FIELDS OF M31". United States. https://doi.org/10.1088/0004-6256/141/5/171.
@article{osti_21583128,
title = {HST/ACS OBSERVATIONS OF RR LYRAE STARS IN SIX ULTRA-DEEP FIELDS OF M31},
author = {Jeffery, E J and Smith, E and Brown, T M and Kalirai, J S and Ferguson, H C and Sweigart, A V and Guhathakurta, P and Renzini, A and Rich, R. M., E-mail: jeffery@stsci.edu},
abstractNote = {We present HST/ACS observations of RR Lyrae variable stars in six ultra-deep fields of the Andromeda galaxy (M31), including parts of the halo, disk, and giant stellar stream. Past work on the RR Lyrae stars in M31 has focused on various aspects of the stellar populations that make up the galaxy's halo, including their distances and metallicities. This study builds upon this previous work by increasing the spatial coverage (something that has been lacking in previous studies) and by searching for these variable stars in constituents of the galaxy not yet explored. Besides the 55 RR Lyrae stars we found in our initial field located 11 kpc from the galactic nucleus, we find additional RR Lyrae stars in four of the remaining five ultra-deep fields as follows: 21 in the disk, 24 in the giant stellar stream, three in the halo field 21 kpc from the galactic nucleus, and five in one of the halo fields at 35 kpc. No RR Lyrae stars were found in the second halo field at 35 kpc. The RR Lyrae populations of these fields appear to be mostly of Oosterhoff I type, although the 11 kpc field appears to be intermediate or mixed. We will discuss the properties of these stars including period and reddening distributions. We calculate metallicities and distances for the stars in each of these fields using different methods and compare the results, to an extent that has not yet been done. We compare these methods not just on RR Lyrae stars in our M31 fields, but also on a data set of Milky Way field RR Lyrae stars.},
doi = {10.1088/0004-6256/141/5/171},
url = {https://www.osti.gov/biblio/21583128}, journal = {Astronomical Journal (New York, N.Y. Online)},
issn = {1538-3881},
number = 5,
volume = 141,
place = {United States},
year = {Sun May 15 00:00:00 EDT 2011},
month = {Sun May 15 00:00:00 EDT 2011}
}