Bibcode
Martínez-Vázquez, C. E.; Monelli, M.; Bono, G.; Stetson, P. B.; Ferraro, I.; Bernard, E. J.; Gallart, C.; Fiorentino, G.; Iannicola, G.; Udalski, A.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 454, Issue 2, p.1509-1516
Advertised on:
12
2015
Citations
51
Refereed citations
44
Description
We identified and characterized the largest (536) RR Lyrae (RRL) sample
in a Milky Way dSph satellite (Sculptor) based on optical photometry
data collected over ˜24 years. The RRLs display a spread in
V-magnitude (˜0.35 mag) which appears larger than photometric
errors and the horizontal branch (HB) luminosity evolution of a
mono-metallic population. Using several calibrations of two different
reddening free and metal independent period-Wesenheit relations we
provide a new distance estimate μ = 19.62 mag (σμ
= 0.04 mag) that agrees well with literature estimates. We constrained
the metallicity distribution of the old population, using the
MI period-luminosity relation, and we found that it ranges
from -2.3 to -1.5 dex. The current estimate is narrower than suggested
by low and intermediate spectroscopy of RGBs (Δ [Fe/H]≤ 1.5).
We also investigated the HB morphology as a function of the
galactocentric distance. The HB in the innermost regions is dominated by
red HB stars and by RRLs, consistent with a more metal-rich population,
while in the outermost regions it is dominated by blue HB stars and RRLs
typical of a metal-poor population. Our results suggest that fast
chemical evolution occurred in Sculptor, and that the radial gradients
were in place at an early epoch.
Related projects
![A laser beam launched from the VLT's Yepun telescope and in background a majestic view of the southern sky, with the disc of the Milky Way crossing the image and the Magellanic Clouds on the top right A view of our Milky Way galaxy with its close neighbors the Magellanic Clouds](/sites/default/files/styles/crop_square_2_2_to_320px/public/images/project/imagen-battaglia.jpg?h=fc948ffc&itok=zzZBOpLu)
Galaxy Evolution in the Local Group
Galaxy formation and evolution is a fundamental Astrophysical problem. Its study requires “travelling back in time”, for which there are two complementary approaches. One is to analyse galaxy properties as a function of red-shift. Our team focuses on the other approach, called “Galactic Archaeology”. It is based on the determination of galaxy
Matteo
Monelli