Bibcode
Rozas, Maite; Cardwell, Andrew; Zurita, Almudena; Beckman, John E.
Bibliographical reference
In: New quests in stellar astrophysics: the link between stars and cosmology. Proceedings of the international conference held in Puerto Vallarta, México, 26-30 March 2001, edited by Miguel Chávez, Alessandro Bressan, Alberto Buzzoni and Divakara Mayya. Astrophysics and Space Science Library, Vol. 274, Dordrecht: Kluwer Academic Publishers, ISBN 1-4020-0644-6, 2002, p. 147 - 150
Advertised on:
0
2002
Citations
0
Refereed citations
0
Description
We propose the use of the H II region luminosity function (LF) as a
refined powerful standard candle for extragalactic distances. We have
found evidence of a change in the properties of H II regions in spirals
at a fixed luminosity in Hα which we term the Strömgren
luminosity (LHα = 3.39×1038 erg
s-1). The key piece of evidence is the presence in the
Hα H II region LF of a change in gradient and a local sharp peak.
The invariance and high luminosity of the change measured in the LF was
proposed in previous studies as a possible secondary standard candle,
but it is calibrated here for the first time using the LFs of NGC 925,
NGC 4535 and M100, whose Cepheid distances have been determined in the
HST Extragalactic Distance Scale Key Project. Using this method we
derive a value of H0 of 73±7 km s-1
Mpc-1.