The stellar populations of the M31 halo substructure
(2005) In Astrophysical Journal 622(2). p.109-112- Abstract
- We present the first results from our survey of stellar substructure in the outskirts of M31 using the Advanced Camera for Surveys on board the Hubble Space Telescope. We discuss the stellar populations associated with five prominent stellar overdensities discovered during the course of our panoramic ground-based imaging survey with the Isaac Newton Telescope Wide-Field Camera; a sixth pointing targets a region of "clean" halo. The color-magnitude diagrams, which contain between approximate to 10,000 and 90,000 stars and reach 4 mag below the horizontal branch, reveal clear variations in morphology between most fields, indicating that the age and/or metallicity mix of stars is not constant at large radius. This directly confirms the... (More)
- We present the first results from our survey of stellar substructure in the outskirts of M31 using the Advanced Camera for Surveys on board the Hubble Space Telescope. We discuss the stellar populations associated with five prominent stellar overdensities discovered during the course of our panoramic ground-based imaging survey with the Isaac Newton Telescope Wide-Field Camera; a sixth pointing targets a region of "clean" halo. The color-magnitude diagrams, which contain between approximate to 10,000 and 90,000 stars and reach 4 mag below the horizontal branch, reveal clear variations in morphology between most fields, indicating that the age and/or metallicity mix of stars is not constant at large radius. This directly confirms the existence of large-scale population inhomogeneities within the halo of M31 and lends further support to the notion that M31 has formed, at least in part, through satellite accretions. We find a striking similarity between the populations of the giant stellar stream and those of another overdensity, the NE shelf, which lies northeast of the galaxy center. If these overdensities are associated with the same population, then the difference in their red clump magnitudes implies that the NE shelf lies in front of the stream by several tens of kiloparsecs, in good agreement with recent orbit calculations for the stream progenitor. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/247218
- author
- Ferguson, A M N ; Johnson, R A ; Faria, Daniel LU ; Irwin, M J ; Ibata, R A ; Johnston, K V ; Lewis, G F and Tanvir, N R
- organization
- publishing date
- 2005
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- galaxies : stellar content, : individual ( M31), galaxies, galaxies : halos, galaxies : evolution, galaxies : formation, galaxies : structure
- in
- Astrophysical Journal
- volume
- 622
- issue
- 2
- pages
- 109 - 112
- publisher
- American Astronomical Society
- external identifiers
-
- wos:000228093800009
- scopus:19944386582
- ISSN
- 0004-637X
- DOI
- 10.1086/429371
- language
- English
- LU publication?
- yes
- id
- 0ac965b5-1337-4d72-a403-f2daa8320083 (old id 247218)
- date added to LUP
- 2016-04-01 16:49:27
- date last changed
- 2022-12-12 21:38:10
@article{0ac965b5-1337-4d72-a403-f2daa8320083,
abstract = {{We present the first results from our survey of stellar substructure in the outskirts of M31 using the Advanced Camera for Surveys on board the Hubble Space Telescope. We discuss the stellar populations associated with five prominent stellar overdensities discovered during the course of our panoramic ground-based imaging survey with the Isaac Newton Telescope Wide-Field Camera; a sixth pointing targets a region of "clean" halo. The color-magnitude diagrams, which contain between approximate to 10,000 and 90,000 stars and reach 4 mag below the horizontal branch, reveal clear variations in morphology between most fields, indicating that the age and/or metallicity mix of stars is not constant at large radius. This directly confirms the existence of large-scale population inhomogeneities within the halo of M31 and lends further support to the notion that M31 has formed, at least in part, through satellite accretions. We find a striking similarity between the populations of the giant stellar stream and those of another overdensity, the NE shelf, which lies northeast of the galaxy center. If these overdensities are associated with the same population, then the difference in their red clump magnitudes implies that the NE shelf lies in front of the stream by several tens of kiloparsecs, in good agreement with recent orbit calculations for the stream progenitor.}},
author = {{Ferguson, A M N and Johnson, R A and Faria, Daniel and Irwin, M J and Ibata, R A and Johnston, K V and Lewis, G F and Tanvir, N R}},
issn = {{0004-637X}},
keywords = {{galaxies : stellar content; : individual ( M31); galaxies; galaxies : halos; galaxies : evolution; galaxies : formation; galaxies : structure}},
language = {{eng}},
number = {{2}},
pages = {{109--112}},
publisher = {{American Astronomical Society}},
series = {{Astrophysical Journal}},
title = {{The stellar populations of the M31 halo substructure}},
url = {{http://dx.doi.org/10.1086/429371}},
doi = {{10.1086/429371}},
volume = {{622}},
year = {{2005}},
}