An HST/ACS View of the Inhomogeneous Outer Halo of M31

Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Accepted for publication in MNRAS. 10 pages, 6 figures

Scientific paper

We present a high precision photometric view of the stellar populations in the outer halo of M31, using data taken with the Hubble Space Telescope Advanced Camera for Surveys (HST/ACS). We analyse the field populations adjacent to 11 luminous globular clusters which sample the galactocentric radial range 18 < R < 100 kpc and reach a photometric depth of ~2.5 magnitudes below the horizontal branch (m_F814W ~27 mag). The colour-magnitude diagrams (CMDs) are well populated out to ~60 kpc and exhibit relatively metal-rich red giant branches, with the densest fields also showing evidence for prominent red clumps. We use the Dartmouth isochrones to construct metallicity distribution functions (MDFs) which confirm the presence of dominant populations with <[Fe/H]> = -0.6 to -1.0 dex and considerable metallicity dispersions of 0.2 to 0.3 dex (assuming a 10 Gyr population and scaled-Solar abundances). The average metallicity over the range 30 - 60 kpc is [Fe/H] = -0.8 +/- 0.14 dex, with no evidence for a significant radial gradient. Metal-poor stars ([Fe/H] <= -1.3) typically account for < 10-20 % of the population in each field, irrespective of radius. Assuming our fields are unbiased probes of the dominant stellar populations in these parts, we find that the M31 outer halo remains considerably more metal-rich than that of the Milky Way out to at least 60 kpc.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

An HST/ACS View of the Inhomogeneous Outer Halo of M31 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with An HST/ACS View of the Inhomogeneous Outer Halo of M31, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An HST/ACS View of the Inhomogeneous Outer Halo of M31 will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-648148

All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.