Abstract / Description of output
We present a renewed look at M31's giant stellar stream along with the
nearby structures streams C and D, exploiting a new algorithm capable of
fitting to the red giant branch (RGB) of a structure in both colour and
magnitude space. Using this algorithm, we are able to generate
probability distributions in distance, metallicity and RGB width for a
series of subfields spanning these structures. Specifically, we confirm
a distance gradient of approximately 20 kpc per degree along a 6 deg
extension of the giant stellar stream, with the farthest subfields from
M31 lying ˜120 kpc more distant than the innermost subfields.
Further, we find a metallicity that steadily increases from
-0.7^{+0.1}_{-0.1} to -0.2^{+0.2}_{-0.1} dex along the inner half of the
stream before steadily dropping to a value of -1.0^{+0.2}_{-0.2} dex at
the farthest reaches of our coverage. The RGB width is found to increase
rapidly from 0.4^{+0.1}_{-0.1} to 1.1^{+0.2}_{-0.1} dex in the inner
portion of the stream before plateauing and decreasing marginally in the
outer subfields of the stream. In addition, we estimate stream C to lie
at a distance between 794 and 862 kpc and stream D between 758 and 868
kpc. We estimate the median metallicity of stream C to lie in the range
-0.7 to -1.6 dex and a metallicity of -1.1^{+0.3}_{-0.2} dex for stream
D. RGB widths for the two structures are estimated to lie in the range
0.4-1.2 dex and 0.3-0.7 dex, respectively. In total, measurements are
obtained for 19 subfields along the giant stellar stream, four along
stream C, five along stream D and three general M31 spheroid fields for
comparison. We thus provide a higher resolution coverage of the
structures in these parameters than has previously been available in the
literature.
Original language | English |
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Pages (from-to) | 3282-3298 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 458 |
Issue number | 3 |
Early online date | 7 Mar 2016 |
DOIs | |
Publication status | Published - 21 May 2016 |
Keywords / Materials (for Non-textual outputs)
- Local Group
- galaxies: structure