Properties of the lower segment of M31’s North West stream
ABSTRACT We present a kinematic and spectroscopic analysis of 40 red giant branch stars, in 9 fields, exquisitely delineating the lower segment of the North West stream (NW-K2), which extends for $\sim$80 kpc from the centre of the Andromeda galaxy. We measure the stream’s systemic velocity as −439.3$^{+4.1}_{-3.8}$ km s$^{-1}$ with a velocity dispersion =16.4$^{+5.6}_{-3.8}$ km s$^{-1}$ that is in keeping with its progenitor being a dwarf galaxy. We find no detectable velocity gradient along the stream. We determine $-1.3\pm0.1$$\le$$\langle[\mathrm{ Fe/H}]_{\rm spec}\rangle$$\le$$-1.2\pm0.8$ but find no metallicity gradient along the stream. We are able to plausibly associate NW-K2 with the globular clusters PAndAS-04, PAndAS-09, PAndAS-10, PAndAS-11, and PAndAS-12 but not with PAndAS-13 or PAndAS-15, which we find to be superimposed on the stream but not kinematically associated with it.
Authors
- Rodrigo Ibata (ORCID: https://orcid.org/0000-0002-3292-9709)
- Denis Erkal
- R. Michael Rich (ORCID: https://orcid.org/0000-0003-0427-8387)
- Janet Preston (ORCID: https://orcid.org/0000-0003-4506-8263)
- Michelle Collins (ORCID: https://orcid.org/0000-0002-1693-3265)
Institutions
- University of California, Los Angeles (US)
- Observatoire astronomique de Strasbourg (FR)
- University of Surrey (GB)
- Université de Strasbourg (FR)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society
- Published
- 2024-12-11
- DOI
- https://doi.org/10.1093/mnras/stae2726
- Primary Topic
- Geophysics and Gravity Measurements
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Aeronautics and Space Administration
- W. M. Keck Foundation
- California Institute of Technology
- Centre National de la Recherche Scientifique
- Commissariat à l'Énergie Atomique et aux Énergies Alternatives
- Institut national des sciences de l'Univers