Deep, wide-field g,i imaging of And XXXI Virtual Observatory Resource

Authors
  1. Rhode K.L.
  2. Crnojevic D.
  3. Sand D.J.
  4. Janowiecki S.
  5. Young M.D.
  6. Spekkens K.
  7. Published by
    CDS
Abstract

We present results from WIYN pODI imaging of Lacerta I (And XXXI), a satellite dwarf galaxy discovered in the outskirts of the Andromeda galaxy (M31) in Pan-STARRS1 survey data. Our deep, wide-field g,i photometry reaches ~3mag fainter than the photometry in the Pan-STARRS1 discovery paper and allows us to trace the stellar population of Lac I beyond two half-light radii from the galaxy center. We measure a Tip of the Red Giant Branch distance for Lac I of (m-M)_0_=24.44+/-0.11mag (773+/-40kpc, or 264+/-6kpc from M31), which is consistent with the Pan-STARRS1 distance. We use a maximum-likelihood technique to derive structural properties for the galaxy, and find a half-light radius (r_h_) of 3.24+/-0.21' (728+/-47pc), ellipticity ({epsilon}) of 0.44+/-0.03, total magnitude M_V_=-11.4+/-0.3, and central surface brightness {mu}_V,0_=24.8+/-0.3mag/arcsec^2^. We find no H I emission in archival data and set a limit on Lac I's neutral gas mass-to-light ratio of M_HI_/L_V_<0.06M_{sun}_/L_{sun}_, confirming Lac I as a gas-poor dwarf spheroidal galaxy. Photometric metallicities derived from Red Giant Branch stars within 2 r_h_ yield a median [Fe/H] of -1.68+/-0.03, which is more metal-rich than the spectroscopically derived value from Martin+ (2014ApJ...793L..14M). Combining our measured magnitude with this higher metallicity estimate places Lac I closer to its expected position on the luminosity-metallicity relation for dwarf galaxies.

Keywords
  1. galaxies
  2. photometry
  3. visible-astronomy
  4. sloan-photometry
Bibliographic source Bibcode
2017ApJ...836..137R
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/836/137
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJ/836/137
Document Object Identifer DOI
doi:10.26093/cds/vizier.18360137

Access

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http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/836/137
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History

2017-10-25T13:21:53Z
Resource record created
2017-10-25T13:21:53Z
Created
2017-12-13T18:41:48Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr