Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 2002
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002aas...201.2303l&link_type=abstract
American Astronomical Society, 201st AAS Meeting, #23.03; Bulletin of the American Astronomical Society, Vol. 34, p.1143
Astronomy and Astrophysics
Astronomy
1
Scientific paper
Opportunities to directly compare distances estimated by two primary extragalactic distance indicators are rare. While Cepheid variables remain the most widely used and well studied extragalactic primary distance indicators, the Expanding Photosphere Method (EPM) of supernova (SN) distance determination is a powerful primary extragalactic distance indicator as well, providing distance estimates completely independent of the Cepheid scale. However, there have never been any measurements of Cepheids in a galaxy that has hosted a well-observed, spectroscopically and photometrically normal, type II-Plateau (II-P) supernova, the classic variety of core-collapse event to which EPM-derived distances are most robust. The appearance of SN 1999em, a bright, extremely well-observed SN II-P in the nearby SBc galaxy NGC 1637 (v = 717 km s-1), offers an outstanding opportunity to test the consistency between these two techniques. Two independently-derived EPM distances exist: d = 7.5 +/- 0.5 Mpc (Hamuy et al. 2001, ApJ, 558, 615), and d = 8.2 +/- 0.6 Mpc (Leonard et al. 2002, PASP, 114, 35). These EPM distances to SN 1999em agree with distances previously derived to NGC 1637 through analysis of the galaxy's brightest red supergiants (d = 7.8 Mpc; Sohn & Davidge 1998, AJ, 115, 130) as well as the Tully-Fisher relation (d = 8.9 Mpc; Tully 1988, Nearby Gal. Cat.). Using Hubble Space Telescope Cycle 10 observations, we present the discovery of several dozen Cepheid variables in NGC 1637. We derive the distance to NGC 1637 through the analysis of its Cepheid variable stars, and find that a significant discrepancy exists between the Cepheid-based distance and that derived through the EPM. Implications of this result on the extragalactic distance scale are discussed. Support for this work was provided by NASA through grant number GO-9155 from the Space Telescope Science Institute.
Kanbur Shashi M.
Leonard Douglas C.
Ngeow Chow Choong
Tanvir Nial R.
No associations
LandOfFree
The Cepheid Distance to NGC 1637: A Direct Comparison with the EPM Distance to SN 1999em 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 The Cepheid Distance to NGC 1637: A Direct Comparison with the EPM Distance to SN 1999em, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Cepheid Distance to NGC 1637: A Direct Comparison with the EPM Distance to SN 1999em will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1889576