The Pisces Plume and the Magellanic Wake

Abstract

Using RR Lyrae stars in the Gaia Data Release 2 and Pan-STARRS1 we study the properties of the Pisces Overdensity, a diffuse sub-structure in the outer halo of the Milky Way. We show that along the line of sight, Pisces appears as a broad and long plume of stars stretching from 40 to 110 kpc with a steep distance gradient. On the sky Pisces's elongated shape is aligned with the Magellanic Stream. Using follow-up VLT FORS2 spectroscopy, we have measured the velocity distribution of the Pisces candidate member stars and have shown it to be as broad as that of the Galactic halo but offset to negative velocities. Using a suite of numerical simulations, we demonstrate that the structure has many properties in common with the predicted behaviour of the Magellanic wake, i.e. the Galactic halo overdensity induced by the in-fall of the Magellanic Clouds.

arXiv commentSubmitted to MNRAS Letters. Comments welcome!

References in corpus (24)

• Ultralight scalars as cosmological dark matter
• A distance to the Large Magellanic Cloud that is precise to one per cent
• New Understanding of Large Magellanic Cloud Structure, Dynamics and Orbit from Carbon Star Kinematics
• Are the Magellanic Clouds on their First Passage about the Milky Way?
• AGAMA: Action-based galaxy modelling architecture
• The total mass of the Large Magellanic Cloud from its perturbation on the Orphan stream
• The Milky Way stellar halo out to 40 kpc : Squashed, broken but smooth
• Substructure revealed by RR Lyraes in SDSS Stripe 82
• The Origin of the Magellanic Stream and Its Leading Arm
• Precession of the Sagittarius stream
• A timing constraint on the (total) mass of the Large Magellanic Cloud
• Quantifying Kinematic Substructure in the Milky Way's Stellar Halo
• A Magellanic Origin of the DES Dwarfs
• Response of the Milky Way's disc to the Large Magellanic Cloud in a first infall scenario
• The shape of the Galactic halo with $Gaia$ DR2 RR Lyrae. Anatomy of an ancient major merger
• Piercing the Milky Way: an all-sky view of the Orphan Stream
• The Halo's Ancient Metal-Rich Progenitor Revealed with BHB Stars
• Action-based distribution functions for spheroidal galaxy components
• Distant field BHB stars and the mass of the Galaxy I: Classification of halo A-type stars
• Gaia Data Release 2: Summary of the variability processing & analysis results
• First Detection of the [OIII] 88 micron Line at High Redshifts: Characterizing the Starburst and Narrow Line Regions in Extreme Luminosity Systems
• Modelling the Tucana III stream - a close passage with the LMC
• Halo Velocity Groups in the Pisces Overdensity
• Stellar streams around the Magellanic Clouds in 4D

Cited by in corpus (45)

• Mapping the Stellar Halo with the H3 Spectroscopic Survey
• The Southern Stellar Stream Spectroscopic Survey ($S^5$): Overview, Target Selection, Data Reduction, Validation, and Early Science
• Measuring the Mass of the Large Magellanic Cloud with Stellar Streams Observed by $S^5$
• The DECam Local Volume Exploration Survey: Overview and First Data Release
• All-Sky Dynamical Response of the Galactic Halo to the Large Magellanic Cloud
• Chemo-kinematics of the $Gaia$ RR Lyrae: the halo and the disc
• $S^5$: Probing the Milky Way and Magellanic Clouds potentials with the 6-D map of the Orphan-Chenab stream
• Detection of the LMC-induced sloshing of the Galactic halo
• Measuring the Milky Way mass distribution in the presence of the LMC
• The mass of the Milky Way out to 100 kpc using halo stars
• Galactic Archaeology with Gaia
• The effect of the LMC on the Milky Way system
• Equilibrium models of the Milky Way mass are biased high by the LMC
• The effect of the deforming dark matter haloes of the Milky Way and the Large Magellanic Cloud on the Orphan-Chenab stream
• Quantifying the Stellar Halo's Response to the LMC's Infall with Spherical Harmonics
• Discovery of the Magellanic Stellar Stream Out to 100 Kiloparsecs
• Distant Echoes of the Milky Way's Last Major Merger
• Mapping the anisotropic Galactic stellar halo with Blue Horizontal Branch stars
• Structure, Kinematics, and Observability of the Large Magellanic Cloud's Dynamical Friction Wake in Cold vs. Fuzzy Dark Matter
• Models of Distorted and Evolving Dark Matter Halos
• Tidally stripped halo stars from the Large Magellanic Cloud in the Galactic North
• Exploring the interaction between the MW and LMC with a large sample of blue horizontal branch stars from the DESI survey
• Comparing hypervelocity star populations from the Large Magellanic Cloud and the Milky Way
• All-Sky Kinematics of the Distant Halo: The Reflex Response to the LMC
• Vertical structure and kinematics of the LMC disc from SDSS/Gaia
• Galactic Mass Estimates using Dwarf Galaxies as Kinematic Tracers
• The LMC impact on the kinematics of the Milky Way satellites: clues from the running solar apex
• The heavy-elements heritage of the falling sky
• A determination of the LMC dark matter subhalo mass using the MW halo stars in its gravitational wake
• On the chaos induced by the Galactic bar on the orbits of nearby halo stars
• Mapping the Distant and Metal-Poor Milky Way with SDSS-V
• Following the tidal trail: a history of modeling the Magellanic Stream
• The Pristine survey XXVIII. Journey to the Galactic outskirts: Mapping the outer halo red giant stars down to the very metal-poor end
• Discovery of NES, an extended tidal structure in the North-East of the Large Magellanic Cloud
• A Simulation Based Inference Approach to the Dynamics of the MW-LMC System -- Validation
• Flattening of dark matter cusps during mergers: model of M31
• The neutron-capture and alpha-elements abundance ratios scatter in old stellar populations. Cosmological simulations of the stellar halo
• The Chemodynamical Nature of the Triangulum-Andromeda Overdensity
• How do the dynamics of the Milky Way -- Large Magellanic Cloud system affect gamma-ray constraints on particle dark matter?
• Effect of the Solar dark matter wake on planets
• Stellar halo striations from assumptions of axisymmetry
• Quantifying the Milky Way, LMC and their interaction using all-sky kinematics of outer halo stars
• Mapping the Distorted Dark Matter Distribution of the LMC-SMC System Prior to Milky Way Infall with Basis Function Expansions
• The orbital dynamics of the LMC and SMC about the Milky Way
• Tracing Milky Way substructure with an RR Lyrae hierarchical clustering forest