CfA4: Light curves for 94 type Ia supernovae

Malcolm Hicken, Peter Challis, Robert P. Kirshner, Armin Rest, Claire E. Cramer, W. Michael Wood-Vasey, Gaspar Bakos, Perry Berlind, Warren R. Brown, Nelson Caldwell, Mike Calkins, Thayne Currie, Kathy De Kleer, Gil Esquerdo, Mark Everett, Emilio Falco, Jose Fernandez, Andrew S. Friedman, Ted Groner, Joel HartmanMatthew J. Holman, Robert Hutchins, Sonia Keys, David Kipping, Dave Latham, George H. Marion, Gautham Narayan, Michael Pahre, Andras Pal, Wayne Peters, Gopakumar Perumpilly, Ben Ripman, Brigitta Sipocz, Andrew Szentgyorgyi, Sumin Tang, Manuel A.P. Torres, Amali Vaz, Scott Wolk, Andreas Zezas

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158 Scopus citations


We present multi-band optical photometry of 94 spectroscopically confirmed Type Ia supernovae (SNe Ia) in the redshift range 0.0055-0.073, obtained between 2006 and 2011. There are a total of 5522 light-curve points. We show that our natural-system SN photometry has a precision of ≲ 0.03mag in BVr′i′, ≲ 0.06mag in u′, and ≲ 0.07mag in U for points brighter than 17.5mag and estimate that it has a systematic uncertainty of 0.014, 0.010, 0.012, 0.014, 0.046, and 0.073mag in BVr′i′u′ U, respectively. Comparisons of our standard-system photometry with published SN Ia light curves and comparison stars reveal mean agreement across samples in the range of 0.00-0.03mag. We discuss the recent measurements of our telescope-plus-detector throughput by direct monochromatic illumination by Cramer et al. This technique measures the whole optical path through the telescope, auxiliary optics, filters, and detector under the same conditions used to make SN measurements. Extremely well characterized natural-system passbands (both in wavelength and over time) are crucial for the next generation of SN Ia photometry to reach the 0.01mag accuracy level. The current sample of low-z SNe Ia is now sufficiently large to remove most of the statistical sampling error from the dark-energy error budget. But pursuing the dark-energy systematic errors by determining highly accurate detector passbands, combining optical and near-infrared (NIR) photometry and spectra, using the nearby sample to illuminate the population properties of SNe Ia, and measuring the local departures from the Hubble flow will benefit from larger, carefully measured nearby samples.

Original languageEnglish (US)
Article number12
JournalAstrophysical Journal, Supplement Series
Issue number2
StatePublished - Jun 2012

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • supernovae: general


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