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Dwarf spheroidal satellites of M31: I. Variable stars and stellar populations in Andromeda XIX

Authors :
M. Fumana
Stefano Gallozzi
Marcella Marconi
Vincenzo Ripepi
Ilaria Musella
Vincenzo Testa
Alessia Garofalo
Konstantina Boutsia
Felice Cusano
Luciana Federici
Gisella Clementini
Michele Cignoni
Cusano, Felice
Clementini, Gisella
Garofalo, Alessia
Cignoni, Michele
Federici, Luciana
Marconi, Marcella
Musella, Ilaria
Ripepi, Vincenzo
Boutsia, Konstantina
Fumana, Marco
Gallozzi, Stefano
Testa, Vincenzo
Publication Year :
2013
Publisher :
arXiv, 2013.

Abstract

We present B,V time-series photometry of Andromeda XIX (And XIX), the most extended (half-light radius of 6.2') of Andromeda's dwarf spheroidal companions, that we observed with the Large Binocular Cameras at the Large Binocular Telescope. We surveyed a 23'x 23' area centered on And XIX and present the deepest color magnitude diagram (CMD) ever obtained for this galaxy, reaching, at V~26.3 mag, about one magnitude below the horizontal branch (HB). The CMD shows a prominent and slightly widened red giant branch, along with a predominantly red HB, which, however, extends to the blue to significantly populate the classical instability strip. We have identified 39 pulsating variable stars, of which 31 are of RR Lyrae type and 8 are Anomalous Cepheids (ACs). Twelve of the RR Lyrae variables and 3 of the ACs are located within And XIX's half light radius. The average period of the fundamental mode RR Lyrae stars ( = 0.62 d, \sigma= 0.03 d) and the period-amplitude diagram qualify And XIX as an Oosterhoff-Intermediate system. From the average luminosity of the RR Lyrae stars ( = 25.34 mag, \sigma= 0.10 mag) we determine a distance modulus of (m-M)$_0$=$24.52\pm0.23$ mag in a scale where the distance to the Large Magellanic Cloud (LMC) is $18.5\pm0.1$ mag. The ACs follow a well defined Period-Wesenheit (PW) relation that appears to be in very good agreement with the PW relationship defined by the ACs in the LMC.<br />Comment: accepted for publication in ApJ

Details

Database :
OpenAIRE
Accession number :
edsair.doi.dedup.....df6287ce7e8faffbd8f1355157677935
Full Text :
https://doi.org/10.48550/arxiv.1310.1809