English

Distance to the Sagittarius Dwarf Galaxy using MACHO Project RR Lyrae stars

Solar and Stellar Astrophysics 2009-11-13 v1 Astrophysics of Galaxies

Abstract

We derive the distance to the northern extension of the Sagittarius (Sgr) dwarf spheroidal galaxy from 203 Sgr RR0 Lyrae stars found in the MACHO database. Their distances are determined differentially with respect to 288 Galactic Bulge RR0 Lyrae stars also found in the MACHO data. We find a distance modulus difference of 2.41 mags at ll = 5^{\circ} and bb = -8^{\circ} and that the extension of the Sgr galaxy towards the galactic plane is inclined toward us. Assuming RGC\rm R_{GC} = 8 kpc, this implies the distance to these stars is (mM)0(m-M)_0 = 16.97 ±\pm 0.07 mags, which corresponds to D = 24.8 ±\pm 0.8 kpc. Although this estimate is smaller than previous determinations for this galaxy and agrees with previous suggestions that Sgr's body is truly closer to us, this estimate is larger than studies at comparable galactic latitudes.

Keywords

Cite

@article{arxiv.0903.3040,
  title  = {Distance to the Sagittarius Dwarf Galaxy using MACHO Project RR Lyrae stars},
  author = {Andrea Kunder and Brian Chaboyer},
  journal= {arXiv preprint arXiv:0903.3040},
  year   = {2009}
}

Comments

accepted in AJ