M dwarfs in the b201 tile of the VVV survey: Colour-based Selection, Spectral Types and Light Curves

Abstract

The intrinsically faint M dwarfs are the most numerous stars in the Galaxy, have main-sequence lifetimes longer than the Hubble time, and host some of the most interesting planetary systems known to date. Their identification and classification throughout the Galaxy is crucial to unravel the processes involved in the formation of planets, stars and the Milky Way. The ESO Public Survey VVV is a deep near-IR survey mapping the Galactic bulge and southern plane. The VVV b201 tile, located in the border of the bulge, was specifically selected for the characterisation of M dwarfs. We used VISTA photometry to identify M dwarfs in the VVV b201 tile, to estimate their subtypes, and to search for transit-like light curves from the first 26 epochs of the survey. UKIDSS photometry from SDSS spectroscopically identified M dwarfs was used to calculate their expected colours in the $YJH{K}_s$ VISTA system. A colour-based spectral subtype calibration was computed. Possible giants were identified by a $(J-K_s,H_J)$ reduced proper motion diagram. The light curves of 12.8<$K_s$<15.8 colour-selected M dwarfs were inspected for signals consistent with transiting objects. We identified 23,345 objects in VVV b201 with colours consistent with M dwarfs. We provided their spectral types and photometric distances, up to $\sim$ 300 pc for M9s and $\sim$ 1.2 kpc for M4s, from photometry. In the range 12<$K_s$<16, we identified 753 stars as possible giants out of 9,232 M dwarf candidates. While only the first 26 epochs of VVV were available, and 1 epoch was excluded, we were already able to identify transit-like signals in the light curves of 95 M dwarfs and of 12 possible giants. Thanks to its deeper photometry ($\sim$4 magnitudes deeper than 2MASS), the VVV survey will be a major contributor to the discovery and study of M dwarfs and possible companions towards the center of the Milky Way.

arXiv comment11 pages, 4 figures. Accepted for publication in Catalogs and data of Astronomy and Astrophysics

References in corpus (37)

• The Sloan Digital Sky Survey: Technical Summary
• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• GAIA: Composition, Formation and Evolution of the Galaxy
• VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
• A Universal Stellar Initial Mass Function? A Critical Look at Variations
• The PPMXL catalog of positions and proper motions on the ICRS. Combining USNO-B1.0 and 2MASS
• The UKIRT Infrared Deep Sky Survey ZYJHK Photometric System: Passbands and Synthetic Colours
• The Infrared Telescope Facility (IRTF) Spectral Library: Cool Stars
• The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample
• An Infrared Spectroscopic Sequence of M, L and T Dwarfs
• The Occurrence Rate of Small Planets around Small Stars
• Stellar SEDs from 0.3-2.5 Microns: Tracing the Stellar Locus and Searching for Color Outliers in SDSS and 2MASS
• Characterization of M,L and T dwarfs in the Sloan Digital Sky Survey
• VVV DR1: The First Data Release of the Milky Way Bulge and Southern Plane from the Near-Infrared ESO Public Survey VISTA Variables in the Via Lactea
• Metallicity and Temperature Indicators in M dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs
• The Luminosity and Mass Functions of Low-Mass Stars in the Galactic Disk: II. The Field
• Spectroscopic Properties of Cool Stars in the SDSS: An Analysis of Magnetic Activity and a Search for Subdwarfs
• The Sloan Digital Sky Survey Data Release 7 Spectroscopic M Dwarf Catalog I: Data
• A revised estimate of the occurrence rate of terrestrial planets in the habitable zones around kepler m-dwarfs
• An All-Sky Catalog of Bright M Dwarfs
• The Bulge Radial Velocity Assay (BRAVA): II. Complete Sample and Data Release
• Bayesian search for low-mass planets around nearby M dwarfs. Estimates for occurrence rate based on global detectability statistics
• The Bulge Radial Velocity Assay (BRAVA): I. Techniques and a Rotation Curve
• The Southern Proper Motion Program IV. The SPM4 Catalog
• The Luminosity and Mass Functions of Low-Mass Stars in the Galactic Disk: I. The Calibration Region
• M Dwarf Flares from Time-Resolved SDSS Spectra
• Multi-wavelength characterization of stellar flares on low-mass stars using SDSS and 2MASS time domain surveys
• Milky Way demographics with the VVV survey. I. The 84-million star colour-magnitude diagram of the Galactic bulge
• Astrometric and photometric initial mass functions from the UKIDSS Galactic Clusters Survey: I The Pleiades
• Astrometric and photometric initial mass functions from the UKIDSS Galactic Clusters Survey: IV Upper Sco
• The Effects of Close Companions (and Rotation) on the Magnetic Activity of M Dwarfs
• Group finding in the stellar halo using M-giants in 2MASS: An extended view of the Pisces Overdensity?
• Astrometric and photometric initial mass functions from the UKIDSS Galactic Clusters Survey: III Praesepe
• The UKIDSS-2MASS Proper Motion Survey I: Ultracool dwarfs from UKIDSS DR4
• New ultracool subdwarfs identified in large-scale surveys using Virtual Observatory tools: Part I: UKIDSS LAS DR5 vs SDSS DR7
• Astrometric and photometric initial mass functions from the UKIDSS Galactic Clusters Survey: II The Alpha Persei open cluster
• Hunting The Most Distant Stars in the Milky Way: Methods and Initial Results

Cited by in corpus (9)

• VIRAC: The VVV Infrared Astrometric Catalogue
• Constraining the radio-loud fraction of quasars at z>5.5
• Radial velocity information content of M dwarf spectra in the near-infrared
• VVV High proper motion stars I. The catalogue of bright Ks < 13.5 stars
• Updated orbital monitoring and dynamical masses for nearby M-dwarf binaries
• VVVX near-IR photometry for 99 low-mass stars in the Gaia EDR3 Catalog of Nearby Stars
• M-dwarf stars in the b294 field from the VISTA Variables in the Vía Láctea (VVV)
• Search for Exoplanetary Transits in the Galactic Bulge
• Low mass variable stars in the globular cluster NGC 6397