SDSS absolute magnitudes for thin-disc stars based on trigonometric parallaxes

Bilir S., Karaali S., Ak S., Coskunoglu K. B., Yaz E., Cabrera-Lavers A.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol.396, no.3, pp.1589-1595, 2009 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 396 Issue: 3
  • Publication Date: 2009
  • Doi Number: 10.1111/j.1365-2966.2009.14816.x
  • Journal Name: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1589-1595
  • Keywords: stars: distances, Galaxy: disc, solar neighbourhood, DIGITAL SKY SURVEY, SLOAN PHOTOMETRY, MAIN-SEQUENCE, 2MASS, TRANSFORMATIONS, CALIBRATION, SYSTEMS
  • Istanbul University Affiliated: Yes

Abstract

We present a new luminosity-colour relation based on trigonometric parallaxes for thin-disc main-sequence stars in Sloan Digital Sky Survey (SDSS) photometry. We matched stars from the newly reduced Hipparcos catalogue with the ones taken from Two-Micron All-Sky Survey (2MASS) All-Sky Catalogue of Point Sources, and applied a series of constraints, i.e. relative parallax errors (sigma pi/pi <= 0.05), metallicity (-0.30 <= [M/H] = 0.20 dex), age (0 <= t <= 10 Gyr) and surface gravity (logg > 4), and obtained a sample of thin-disc main-sequence stars. Then, we used our previous transformation equations (Bilir et al. 2008a) between SDSS and 2MASS photometries and calibrated the M(g) absolute magnitudes to the (g - r)(0) and (r - i)(0) colours. The transformation formulae between 2MASS and SDSS photometries along with the absolute magnitude calibration provide space densities for bright stars which saturate the SDSS magnitudes.