Proper motion measurements for stars up to $100$ kpc with Subaru HSC and SDSS Stripe 82

Abstract

We present proper motion measurements for more than $0.55$ million main-sequence stars, by comparing astrometric positions of matched stars between the multi-band imaging datasets from the Hyper Suprime-Cam (HSC) Survey and the SDSS Stripe 82. In doing this we use $3$ million galaxies to recalibrate the astrometry and set up a common reference frame between the two catalogues. The exquisite depth and the nearly $12$ years of time baseline between HSC and SDSS enable high-precision measurements of statistical proper motions for stars down to $i\simeq 24$. A validation of our method is demonstrated by the agreement with the $Gaia$ proper motions, to the precision better than $0.1$ mas yr${}^{-1}$. To retain the precision, we make a correction of the subtle effects due to the differential chromatic refraction in the SDSS images based on the comparison with the $Gaia$ proper motions against colour of stars, which is validated using the SDSS spectroscopic quasars. Combining with the photometric distance estimates for individual stars based on the precise HSC photometry, we show a significant detection of the net proper motions for stars in each bin of distance out to $100$ kpc. The two-component tangential velocities after subtracting the apparent motions due to our own motion display rich phase-space structures including a clear signature of the Sagittarius stream in the halo region of distance range $[10,35]$ kpc. We also measure the tangential velocity dispersion in the distance range $5-20$ kpc and find that the data are consistent with a constant isotropic dispersion of $80\pm 10km/s$. More distant stars appear to have random motions with respect to the Galactic centre on average.

accepted by MNRAS, add more details

References in corpus (25)

• The Gaia mission
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• Two Stellar Components in the Halo of the Milky Way
• The Milky Way Tomography with SDSS: II. Stellar Metallicity
• Second Data Release of the Hyper Suprime-Cam Subaru Strategic Program
• Constraints on Earth-mass primordial black holes from OGLE 5-year microlensing events
• Streams, substructures and the early history of the Milky Way
• No large population of unbound or wide-orbit Jupiter-mass planets
• On the Shoulders of Giants: Properties of the Stellar Halo and the Milky Way Mass Distribution
• Light and Motion in SDSS Stripe 82: The Catalogues
• The velocity dispersion and mass profile of the Milky Way
• The mass of our Milky Way
• Limit on the LMC mass from a census of its satellites
• The Sloan Digital Sky Survey Stripe 82 Imaging Data: Depth-Optimized Co-adds Over 300 Deg^2 in Five Filters
• An all-sky proper motion map of the Sagittarius stream using Gaia DR2
• The mass of our Galaxy from satellite proper motions in the Gaia era
• Constraining the Milky Way Mass Profile with Phase-Space Distribution of Satellite Galaxies
• The fall of the Northern Unicorn: Tangential motions in the Galactic Anti-centre with SDSS and Gaia
• A Blueprint for the Milky Way's Stellar Populations: The Power of Large Photometric and Astrometric Surveys
• Sagittarius stream 3-d kinematics from SDSS Stripe 82
• A Deep Proper Motion Catalog Within The Sloan Digital Sky Survey Footprint
• The Metallicity Gradient and Complex Formation History of the Outermost Halo of the Milky Way
• A Versatile and Accurate Method for Halo Mass Determination from Phase-Space Distribution of Satellite Galaxies

Cited by in corpus (7)

• Constraints on the assembly history of the Milky Way's smooth, diffuse stellar halo from the metallicity-dependent, radially-dominated velocity anisotropy profiles probed with K giants and BHB stars using LAMOST, SDSS/SEGUE, and Gaia
• A comparative study of satellite galaxies in Milky Way-like galaxies from HSC, DECaLS and SDSS
• The nature of the Milky Way's stellar halo revealed by the three integrals of motion
• Is the core-cusp problem a matter of perspective: Jeans Anisotropic Modeling against numerical simulations
• Hunting isolated neutron stars with proper motions from wide-area optical surveys
• Exploring faint white dwarfs and the luminosity function with Subaru HSC and SDSS in Stripe 82
• Joint Survey Processing II: Stellar Proper Motions in the COSMOS Field, from Hubble Space Telescope ACS and Subaru Telescope HSC Observations