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Title: Properties of M31. IV. Candidate luminous blue variables from PAndromeda

We perform a study on the optical and infrared photometric properties of known luminous blue variables (LBVs) in M31 using a sample of LBV candidates from the Local Group Galaxy Survey by Masset et al. We find that M31 LBV candidates show photometric variability ranging from 0.375 to 1.576 mag in r {sub P1} during a 3 yr time span observed by the Pan-STARRS 1 Andromeda survey (PAndromeda). Their near-infrared colors also follow the distribution of Galactic LBVs as shown by Oksala et al. We use these features as selection criteria to search for unknown LBV candidates in M31. We thus devise a method to search for candidate LBVs using both optical color from the Local Group Galaxy Survey and infrared color from the Two Micron All Sky Survey, as well as photometric variations observed by PAndromeda. We find four sources exhibiting common properties of known LBVs. These sources also exhibit UV emission as seen from Galaxy Evolution Explorer, which is one of the previously adopted methods of searching for LBV candidates. The locations of the LBVs are well aligned with M31 spiral arms as seen in UV light, suggesting that they are evolved stars at a young age givenmore » their high-mass nature. We compare these candidates with the latest Geneva evolutionary tracks, which show that our new M31 LBV candidates are massive, evolved stars with ages of 10-100 Myr.« less
Authors:
; ; ; ; ; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ; ; ; ; ; ;  [5] ;  [6]
  1. University Observatory Munich, Scheinerstrasse 1, D-81679 Munich (Germany)
  2. Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
  3. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
  4. Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom)
  5. Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)
  6. Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
Publication Date:
OSTI Identifier:
22357180
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 785; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ARMS; COMPARATIVE EVALUATIONS; DISTRIBUTION; EMISSION; GALAXIES; MASS; SKY; STAR EVOLUTION; STARS; ULTRAVIOLET RADIATION