Distances to Galaxies from the Brightest Stars in the Universe

Details Distances to Galaxies from the Brightest Stars in the Universe Distances to Galaxies from the Brightest Stars in the Universe

2011-12-16

arxiv.org/abs/1112.3935v1

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

Review paper to appear in "The Fundamental Cosmic Distance Scale: State of the Art and GAIA Perspective" 2012, Astrophysics an

Scientific paper

Blue Supergiants (BSGs) are the brightest stars in the universe at visual light with absolute magnitudes up to Mv=-10 mag. They are ideal stellar objects for the determination of extragalactic distances, in particular, because the perennial uncertainties troubling most of the other stellar distance indicators, interstellar extinction and metallicity, do not affect them. The quantitative spectral analysis of low resolution spectra of individual BSGs provides accurate stellar parameters and chemical composition, which are then used to determine accurate reddening and extinction from photometry for each individual object. Accurate distances can be determined from stellar gravities and effective temperatures using the "Flux Weighted Gravity - Luminosity Relationship (FGLR)". Most recent results of the quantitative spectral analysis of BSGs in galaxies within and beyond the Local Group based on medium and low resolution spectra obtained with the ESO VLT and the Keck telescopes on Mauna Kea are presented and distances obtained with the FGLR-method are discussed together with the effects of patchy extinction and abundance gradients in galaxies. BSG metallicities and metallicity gradients are compared with results from strong-line HII region studies and the consequences for the empirical calibration of the metallicity dependence of the Cepheid period-luminosity relationship are pointed out. The perspectives of future work are discussed, the use of the giant ground-based telescopes of the next generation such as the TMT on Mauna Kea and the E-ELT and the tremendous value of the GAIA mission to allow for the ultimate calibration of the FGLR using galactic BSGs.

Affiliated with

Also associated with

No associations

Rating

Distances to Galaxies from the Brightest Stars in the Universe does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Distances to Galaxies from the Brightest Stars in the Universe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Distances to Galaxies from the Brightest Stars in the Universe will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-170307