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S. Jha, R. P. Kirshner, P. M. Challis (Harvard-Smithsonian CfA), P. M. Garnavich (Notre Dame)
Type Ia supernovae (SN Ia) have proven to be excellent distance indicators, with an overall homogeneity which yields a good standard candle. A quantifiable heterogeneity, in the form of the SN light curve shape, sharpens our cosmological tool, turning a good standard candle into an excellent calibrated candle. The combination of high luminosity and high precision provides many applications of these distance indicators, from precise verification of the Hubble Law and measurement of the Hubble constant to the measurement of the expansion history and geometry of the Universe, with the tantalizing possibility that the Universe is accelerating at the current epoch.
Almost all of these results rely on photometric observations of SN Ia in the rest-frame optical B, V, R and I passbands. Through a study at the CfA over the last few years, we have expanded this domain, observing a large sample of nearby SN Ia with attention to the near ultraviolet (U-band) and the near infrared (J, H, K) in an effort to refine our understanding of these stellar explosions as well as refine their use as distance indicators. The rest-frame U-band data is particularly relevant to comparisons with SN Ia at high redshift, where rest-frame B and V shift into the observer-frame infrared. The rest-frame infrared data is excellent for untangling the effects of intrinsic variations of SN Ia luminosity from apparent variations due to extinction along the line of sight. We present results from our study, with applications to SN Ia near and far.
This work has been supported in part by an NSF Graduate Research Fellowship.
The author(s) of this abstract have provided an email address for comments about the abstract: mailto:sjha@cfa.harvard.edu