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J/A+A/539/A138      RR Lyr variable stars in M32         (Fiorentino+, 2012)
The ancient population of M 32: RR Lyrae variable stars confirmed.
    Fiorentino G., Contreras Ramos R., Tolstoy E., Clementini G., Saha A.
   <Astron. Astrophys. 539, A138 (2012)>
   =2012A&A...539A.138F
ADC_Keywords: Galaxies, nearby ; Stars, variable ; Photometry, HST

Keywords: Local Group - stars: variables: RR Lyrae -
          galaxies: individual: M 31 - stars: horizontal-branch -
          galaxies: individual: M 32

Abstract:
    Using archival multi-epoch ACS/WFC images in the F606W and F814W
    filters of a resolved stellar field in Local Group dwarf elliptical
    galaxy M 32 we have made an accurate Colour-Magnitude Diagram and a
    careful search for RR Lyr variable stars. We identified 416 bona fide
    RR Lyr stars over our field of view, and their spatial distribution
    shows a rising number density towards the centre of M 32. These new
    observations clearly confirm the tentative result of Fiorentino et al.
    (2010ApJ...708..817F), on a much smaller field of view, associating an
    ancient population of RR Lyr variables to M 32. We associate at least
    83 RR Lyr stars in our field to M 32.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2.dat        82      416   The RR Lyr variable stars we have identified


Byte-by-byte Description of file: table2.dat

   Bytes Format Units   Label     Explanations

   1-  4  A4    ---     Name      Variable name, VNNN (1)
       6  I1    h       RAh       Right ascension (J2000)
   8-  9  I2    min     RAm       Right ascension (J2000)
  11- 17  F7.4  s       RAs       Right ascension (J2000)
      19  A1    ---     DE-       Declination sign (J2000)
  20- 21  I2    deg     DEd       Declination (J2000)
  23- 24  I2    arcmin  DEm       Declination (J2000)
  26- 31  F6.3  arcsec  DEs       Declination (J2000)
  33- 37  F5.3  d       Per       Period
  39- 42  A4    ---     Type      RR Lyrae type (2)
  44- 49  F6.3  mag     <F606W>   Light-curve weighted mean magnitude calibrated
                                   in HST VEGAMAG
  51- 55  F5.3  mag     Vamp      Amplitude in filter F606W
  57- 62  F6.3  mag     <F814W>   light-curve weighted mean magnitude calibrated
                                   in HST VEGAMAG for 2-filter RR Lyrae and
                                   from Dolphot output for 1-filter RR Lyrae
  64- 68  F5.3  mag     Iamp      ?=- Amplitude in filter F814W
                                      (only available for 2-filter RR Lyrae)
  70- 75  F6.3  mag     <V0mag>   ?=- Dereddened mean magnitude <F606W> (3)
  77- 82  F6.3  mag     <I0mag>   ? Dereddened mean magnitude <F814W> (3)

Note (1): The RR Lyrae have been named using their increasing distance from
     the centre of M 32 (RA: 10.67375, DE: 40.8652777800)
Note (2): Pulsation mode RRab corresponds to fundamental and RRc to
     first-overtone pulsators.
Note (3): transformed in Johnson-Cousins photometric system obtained
     following the prescriptions by Sirianni et al. (2005PASP..117.1049S).
     Only available for 2-filter RR Lyrae.


Acknowledgements:
    Giuliana Fiorentino, stregaccia30(at)gmail.com
(End)                                        Patricia Vannier [CDS]  24-Jan-2012