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$80 kpc from the centre of the Andromeda galaxy. We measure the stream's systemic velocity as -439.3${}_{-3.8}^{+4.1}$ km/s with a velocity dispersion = 16.4${}_{-3.8}^{+5.6}$ km/s that is in keeping with its progenitor being a dwarf galaxy. We find no detectable velocity gradient along the stream. We determine $-$1.3$\pm$0.1 $\le$ <[Fe/H]${}_{\mathrm{spec}}$> $\le$ $-$1.2$\pm$0.8 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, 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.

arXiv comment14 pages, 8 figures

References in corpus (78)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The NumPy array: a structure for efficient numerical computation
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The observed properties of dwarf galaxies in and around the Local Group
• The Dartmouth Stellar Evolution Database
• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• The large-scale structure of the Universe
• Extragalactic Science, Cosmology and Galactic Archaeology with the Subaru Prime Focus Spectrograph (PFS)
• The remnants of galaxy formation from a panoramic survey of the region around M31
• A giant stream of metal-rich stars in the halo of the galaxy M31
• Constraining the Milky Way potential with a 6-D phase-space map of the GD-1 stellar stream
• The Haunted Halos of Andromeda and Triangulum: A panorama of galaxy formation in action
• Dark matter and cosmic structure
• The total mass of the Large Magellanic Cloud from its perturbation on the Orphan stream
• The Kinematics, Orbit, and Survival of the Sagittarius Dwarf Spheroidal Galaxy
• Data analysis recipes: Using Markov Chain Monte Carlo
• Galactic Globular Cluster Metallicity Scale from the Calcium Triplet. II. Rankings, Comparisons and Puzzles
• The large-scale structure of the halo of the Andromeda Galaxy Part I: global stellar density, morphology and metallicity properties
• On the accretion origin of a vast extended stellar disk around the Andromeda galaxy
• The NIR Ca II triplet at low metallicity - Searching for extremely low-metallicity stars in classical dwarf galaxies
• Analysis and calibration of CaII triplet spectroscopy of Red Giant Branch stars from VLT/FLAMES observations
• Clumpy Streams from Clumpy Halos: Detecting Missing Satellites with Cold Stellar Structures
• A kinematic study of the Andromeda dwarf spheroidal system
• PAndAS' progeny: extending the M31 dwarf galaxy cabal
• The large-scale structure of the halo of the Andromeda galaxy II. Hierarchical structure in the Pan-Andromeda Archaeological Survey
• Taking measure of the Andromeda halo: a kinematic analysis of the giant stream surrounding M31
• Evidence for an accretion origin for the outer halo globular cluster system of M31
• The SPLASH Survey: Spectroscopy of 15 M31 Dwarf Spheroidal Satellite Galaxies
• The PAndAS view of the Andromeda satellite system - II. Detailed properties of 23 M31 dwarf spheroidal galaxies
• A trio of new Local Group galaxies with extreme properties
• PAndAS' cubs: discovery of two new dwarf galaxies in the surroundings of the Andromeda and Triangulum galaxies
• Age and metallicity gradients in early-type galaxies: A dwarf to giant sequence
• Inferring the Andromeda Galaxy's mass from its giant southern stream with Bayesian simulation sampling
• A kinematically selected, metal-poor stellar halo in the outskirts of M31
• Extensive Globular Cluster Systems Associated with Ultra Diffuse Galaxies in the Coma Cluster
• A sharper view of Pal 5's tails: Discovery of stream perturbations with a novel non-parametric technique
• Extending the Globular Cluster System-Halo Mass Relation to the Lowest Galaxy Masses
• The Globular Cluster Systems of Ultra-Diffuse Galaxies in the Coma Cluster
• Piercing the Milky Way: an all-sky view of the Orphan Stream
• The SPLASH Survey: Internal Kinematics, Chemical Abundances, and Masses of the Andromeda I, II, III, VII, X, and XIV dSphs
• The outer halo globular cluster system of M31 - I. The final PAndAS catalogue
• The globular cluster systems of 54 Coma ultra-diffuse galaxies: statistical constraints from HST data
• $S^5$: Probing the Milky Way and Magellanic Clouds potentials with the 6-D map of the Orphan-Chenab stream
• The outer halo globular cluster system of M31 - II. Kinematics
• $S^5$: The Orbital and Chemical Properties of One Dozen Stellar Streams
• The PAndAS Field of Streams: stellar structures in the Milky Way halo toward Andromeda and Triangulum
• Globular Clusters in Coma Cluster Ultra Diffuse Galaxies (UDGs): Evidence for Two Types of UDG?
• The SPLASH Survey: A Spectroscopic Portrait of Andromeda's Giant Southern Stream
• Kinematics of Outer Halo Globular Clusters in M31
• Strangers in the night: Discovery of a dwarf spheroidal galaxy on its first Local Group infall
• A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, And XI, And XII, and And XIII
• DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of our Nearest Neighbor
• A Keck/DEIMOS Kinematic Study of Andromeda IX: dark matter on the smallest galactic scales
• A Relationship Between Stellar Metallicity Gradients and Galaxy Age in Dwarf Galaxies
• The kinematic identification of a thick stellar disc in M31
• Spectroscopy of the three distant Andromedan satellites Cassiopeia III, Lacerta I, and Perseus I
• The outer halo globular cluster system of M31 - III. Relationship to the stellar halo
• A sub-2% Distance to M31 from Photometrically Homogeneous Near-Infrared Cepheid Period-Luminosity Relations Measured with the Hubble Space Telescope
• A spectroscopic survey of Andromeda's Western Shelf
• Constraining the Milky Way Halo Shape Using Thin Streams
• Young accreted globular clusters in the outer halo of M31
• An Excess of Globular Clusters in UDGs Formed Through Tidal Heating
• Two major accretion epochs in M31 from two distinct populations of globular clusters
• The Hercules satellite: a stellar stream in the Milky Way halo?
• Global Properties of M31's Stellar Halo from the SPLASH Survey: III. Measuring the Stellar Velocity Dispersion Profile
• Substructure and Tidal Streams in the Andromeda Galaxy and its Satellites
• Density Variations in the NW Star Stream of M31
• Stellar Stream and Halo Structure in the Andromeda Galaxy From a Subaru/Hyper Suprime-Cam Survey
• Formation of the Andromeda Giant Stream: Asymmetric Structure and Disc Progenitor
• Evidence for non-axisymmetry in M31 from wide-field kinematics of stars and gas
• The nature of the progenitor of the M31 North-western stream: globular clusters as milestones of its orbit
• A Dwarf Disrupting -- Andromeda XXVII and the North West Stream
• Metallicities of Outer Halo M31 Globular Clusters from Integrated Light Calcium-II Triplet Spectroscopy
• Measuring distances to galaxies with globular cluster velocity dispersions
• The origin of the metallicity distributions of the NE and W stellar shelves in the Andromeda Galaxy