Van Grootel, Valérie ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Alonso, M.L.
Stetson, P.B.
Stellingwerf, R.F.
Language :
English
Title :
The soundtrack of RR Lyrae in Omega Cen at high-frequency
Publication date :
2015
Event name :
EWASS 2012 Symposium "Stellar Populations 55 years after the Vatican Conference"
Event place :
Italy
Event date :
2-4 juillet 2012
Audience :
International
Journal title :
Memorie della Societa Astronomica Italiana
ISSN :
0037-8720
Publisher :
Società Astronomica Italiana, Milano, Italy
Volume :
86
Pages :
253
Commentary :
We present preliminary Sloan u',g'-band light curves for a sample of known RR Lyrae variables in the Galactic globular cluster Omega Cen. Results are based on the partial reduction of multi-band time series photometric data collected during six consecutive nights with the visitor instrument ULTRACAM mounted on the New Technology Telescope (La Silla, ESO). This facility allowed us to simultaneously observe in three different bands (Sloan u',g',r') a field of view of about 6x6 arcminutes. The telescope and the good seeing conditions allowed us to sample the light curves every 15 seconds. We ended up with a data set of about 6,000 images per night per filter, for a total of more than 200,000 images of the selected field. This data set allowed us to detect different kind of variables, such as RR-Lyraes, SX Phoenicis, eclipsing binaries, semi-regulars. More importantly, we were able for the first time to sample at high-frequency cluster RR Lyraes in the u',g'-band and to show in detail the pulsation phases across the dip located along the rising branch of RR-Lyraes.
