skip to main content

Title: Type IIP supernovae as cosmological probes: A SEAM distance to SN1999em

Because of their intrinsic brightness, supernovae make excellent cosmological probes. We describe the spectral-fitting expanding atmosphere method (SEAM) for obtaining distances to Type IIP supernovae (SNe IIP) and present a distance to SN 1999em for which a Cepheid distance exists. Our models give results consistent with the Cepheid distance, even though we have not attempted to tune the underlying hydrodynamical model but have simply chosen the best fits. This is in contradistinction to the expanding photosphere method (EPM), which yields a distance to SN 1999em that is 50 percent smaller than the Cepheid distance. We emphasize the differences between the SEAM and the EPM. We show that the dilution factors used in the EPM analysis were systematically too small at later epochs. We also show that the EPM blackbody assumption is suspect. Since SNe IIP are visible to redshifts as high as z {approx}< 6, with the James Webb Space Telescope, the SEAM may be a valuable probe of the early universe.
Authors:
; ; ;
Publication Date:
OSTI Identifier:
886966
Report Number(s):
LBNL--56193
Journal ID: ISSN 0004-637X; ASJOAB; R&D Project: 43CX01; BnR: 400409900; TRN: US0604149
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 616; Related Information: Journal Publication Date: 12/2004
Research Org:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org:
USDOE; National Science Foundation Grants AST-0204771 andAST-0307323, National Aeronautics and Space Administration GrantsNAG5-8425 and NAG5-3619 and NAG5-3505; IBM SUR Grant, Pole Scientifiquede Modelisation Numerique, Hochstleistungs Rechenzentrum Nord
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BRIGHTNESS; CEPHEIDS; DILUTION; PHOTOSPHERE; PROBES; SUPERNOVAE; UNIVERSE supernovae cosmology