The essence supernova survey: Survey optimization, observations, and supernova photometry

G. Miknaitis, G. Pignata, A. Rest, W. M. Wood-Vasey, S. Blondin, P. Challis, R. C. Smith, C. W. Stubbs, N. B. Suntzeff, R. J. Foley, T. Matheson, J. L. Tonry, C. Aguilera, J. W. Blackman, A. C. Becker, A. Clocchiatti, R. Covarrubias, T. M. Davis, A. V. Filippenko, A. GargP. M. Garnavich, M. Hicken, S. Jha, K. Krisciunas, R. P. Kirshner, B. Leibundgut, W. Li, A. Miceli, G. Narayan, J. L. Prieto, A. G. Rmss, M. E. Salvo, B. P. Schmidt, J. Sollerman, J. Spyromilio, A. Zenteno

Research output: Contribution to journalArticlepeer-review


We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the dark energy equation-of-state parameter, w = P/(pc2). We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to w for a given fixed amount of telescope time. For our survey on the CTIO 4 m telescope, measuring the luminosity distances and redshifts for Supernovae at modest redshifts (z ≈ 0.5± 0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find Supernovae automatically and in nearly real time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their apparent brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4 m telescope's natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 Type Ia supernovae, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for all of the Type Ia Supernovae found by ESSENCE and used in our measurement of w, presented in a companion paper by Wood-Vasey and coworkers.

Original languageEnglish (US)
Pages (from-to)674-693
Number of pages20
JournalAstrophysical Journal
Issue number2 I
StatePublished - 2007


  • Cosmology: observations
  • Methods: data analysis
  • Supernovae: general
  • Surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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