Andromeda XXVII and the North West Stream

DOI

We present a kinematic and spectroscopic analysis of 38 red giant branch stars, in seven fields, spanning the dwarf spheroidal galaxy Andromeda XXVII and the upper segment of the North West Stream. Both features are located in the outer halo of the Andromeda galaxy at a projected radius of 50-80kpc, with the stream extending for ~3{deg} on the sky. Our data are obtained as part of the PAndAS survey and enables us to confirm that Andromeda XXVII's heliocentric distance is 827+/-47kpc and spectroscopic metallicity is -2.1^+0.4^-0.5. We also re-derive Andromeda XXVII's kinematic properties, measuring a systemic velocity =-526.1^+10.0^-11.0_km/s and a velocity dispersion that we find to be non-Gaussian but for which we derive a formal value of 27.0^+2.2^-3.9_km/s. In the upper segment of the North West Stream we measure mean values for the metallicity =-1.8+/-0.4, systemic velocity =-519.4+/-4.0km/s, and velocity dispersion =10.0+/-4.0km/s. We also detect a velocity gradient of 1.7+/-0.3km/s/kpc on an infall trajectory towards M31. With a similar gradient, acting in the same direction, in the lower segment we suggest that the North West Stream is not a single structure. As the properties of the upper segment of the North West Stream and Andromeda XXVII are consistent within 90 per cent confidence limits, it is likely that the two are related and plausible that Andromeda XXVII is the progenitor of this stream.

Cone search capability for table J/MNRAS/490/2905/tablea1 (Properties of observed stars from the masks)

Identifier
DOI http://doi.org/10.26093/cds/vizier.74902905
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/MNRAS/490/2905
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/490/2905
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/490/2905
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/MNRAS/490/2905
Provenance
Creator Preston J.; Collins M.L.M.; Ibata R.A.; Tollerud E.J.; Rich R.M.,Bonaca A.; McConnachie A.W.; Mackey D.; Lewis G.F.; Martin N.F.,Penarrubia J.; Chapman S.C.; Delorme M.
Publisher CDS
Publication Year 2023
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Exoplanet Astronomy; Galactic and extragalactic Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy