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23 High Redshift Supernovae from the IfA Deep Survey: Doubling the SN Sample at z>0.7

Brian J. Barris, John Tonry, Stephane Blondin, Peter Challis, Ryan Chornock, Alejandro Clocchiatti, Alexei Filippenko, Peter Garnavich, Stephen Holland, Saurabh Jha, Robert Kirshner, Kevin Krisciunas, Bruno Leibundgut, Weidong Li, Thomas Matheson, Gajus Miknaitis, Adam Riess, Brian Schmidt, R. Chris Smith, Jesper Sollerman, Jason Spyromilio, Christopher Stubbs, Nicholas Suntzeff, H. Aussel, K. C. Chambers, M. S. Connelley, D. Donovan, J. P. Henry, N. Kaiser, M. C. Liu, E. L. Martin, R. J. Wainscoat

TL;DR

This paper reports photometric and spectroscopic observations of 23 high-redshift supernovae from the IfA Deep Survey, including 9 unambiguous SNe Ia, spanning z=0.34–1.03. It introduces a novel N(N-1)/2 approach to construct light curves from a continuous survey, combines MLCS with cross-checks from BATM and dm15, and uses a marginalized likelihood framework to constrain cosmological parameters. The results, when combined with prior SN data, favor a flat universe with best-fit values around $\Omega_m\approx 0.33$ and $\Omega_\Lambda\approx 0.67$, and they demonstrate that the acceleration evidence remains robust against redshift-dependent systematics. The study highlights the challenges of ground-based SN searches at z~1 and emphasizes the value of homogeneous datasets for cross-checking cosmological inferences, while pointing to space-based surveys as essential for future progress.

Abstract

We present photometric and spectroscopic observations of 23 high redshift supernovae spanning a range of z=0.34-1.03, 9 of which are unambiguously classified as Type Ia. These supernovae were discovered during the IfA Deep Survey, which began in September 2001 and observed a total of 2.5 square degrees to a depth of approximately m=25-26 in RIZ over 9-17 visits, typically every 1-3 weeks for nearly 5 months, with additional observations continuing until April 2002. We give a brief description of the survey motivations, observational strategy, and reduction process. This sample of 23 high-redshift supernovae includes 15 at z>0.7, doubling the published number of objects at these redshifts, and indicates that the evidence for acceleration of the universe is not due to a systematic effect proportional to redshift. In combination with the recent compilation of Tonry et al. (2003), we calculate cosmological parameter density contours which are consistent with the flat universe indicated by the CMB (Spergel et al. 2003). Adopting the constraint that Omega_total = 1.0, we obtain best-fit values of (Omega_m, Omega_Lambda)=(0.33, 0.67) using 22 SNe from this survey augmented by the literature compilation. We show that using the empty-beam model for gravitational lensing does not eliminate the need for Omega_Lambda > 0. Experience from this survey indicates great potential for similar large-scale surveys while also revealing the limitations of performing surveys for z>1 SNe from the ground.

23 High Redshift Supernovae from the IfA Deep Survey: Doubling the SN Sample at z>0.7

TL;DR

This paper reports photometric and spectroscopic observations of 23 high-redshift supernovae from the IfA Deep Survey, including 9 unambiguous SNe Ia, spanning z=0.34–1.03. It introduces a novel N(N-1)/2 approach to construct light curves from a continuous survey, combines MLCS with cross-checks from BATM and dm15, and uses a marginalized likelihood framework to constrain cosmological parameters. The results, when combined with prior SN data, favor a flat universe with best-fit values around and , and they demonstrate that the acceleration evidence remains robust against redshift-dependent systematics. The study highlights the challenges of ground-based SN searches at z~1 and emphasizes the value of homogeneous datasets for cross-checking cosmological inferences, while pointing to space-based surveys as essential for future progress.

Abstract

We present photometric and spectroscopic observations of 23 high redshift supernovae spanning a range of z=0.34-1.03, 9 of which are unambiguously classified as Type Ia. These supernovae were discovered during the IfA Deep Survey, which began in September 2001 and observed a total of 2.5 square degrees to a depth of approximately m=25-26 in RIZ over 9-17 visits, typically every 1-3 weeks for nearly 5 months, with additional observations continuing until April 2002. We give a brief description of the survey motivations, observational strategy, and reduction process. This sample of 23 high-redshift supernovae includes 15 at z>0.7, doubling the published number of objects at these redshifts, and indicates that the evidence for acceleration of the universe is not due to a systematic effect proportional to redshift. In combination with the recent compilation of Tonry et al. (2003), we calculate cosmological parameter density contours which are consistent with the flat universe indicated by the CMB (Spergel et al. 2003). Adopting the constraint that Omega_total = 1.0, we obtain best-fit values of (Omega_m, Omega_Lambda)=(0.33, 0.67) using 22 SNe from this survey augmented by the literature compilation. We show that using the empty-beam model for gravitational lensing does not eliminate the need for Omega_Lambda > 0. Experience from this survey indicates great potential for similar large-scale surveys while also revealing the limitations of performing surveys for z>1 SNe from the ground.

Paper Structure

This paper contains 25 sections, 6 equations, 12 figures.

Table of Contents

  1. Introduction
  2. Searching for Cosmological SNe Ia--Past and Future
  3. The IfA Deep Survey
  4. Observations
  5. Survey Science Observations
  6. Astrometric Observations
  7. Photometric Observations
  8. Pipeline Reductions
  9. Supernova Search
  10. Supernova Discovery
  11. Spectroscopic Observations
  12. Keck-II + ESI
  13. Keck-I + LRIS
  14. VLT + FORS
  15. Supernova Classification
  16. ...and 10 more sections

Figures (12)

  • Figure 1: Configuration of the Suprime-Cam and CFHT+12K fields of view during the IfA Deep Survey. Solid lines depict the two Suprime-Cam fields of view, dashed lines show the coverage of the single 12K field of view. Shown on the left is the layout for Fields 0230, 0438, 0749, and 0848. Shown on the right is the layout for Field 1052.
  • Figure 2: A plot of depth (approximate AB magnitudes) versus size for several recent and historical surveys. Diagonal lines show contours of constant volume. The IfA Deep Survey covers a unique region of this parameter space. SDSS (Sloan Digital Sky Survey, www.sdss.org, York et al. 2000). Deeprange (Postman et al. 1998). EIS (ESO Imaging Survey) Deep, Deep Public (www.eso.org/eis). CFRS (Canada-France Redshift Survey, Lilly et al. 1995). LDSS (Low Dispersion Survey Spectrograph, Glazebrook et al. 1995). CDFS (GOODS/ESO Chandra Deep Field South, www.eso.org/eis). HDF (Hubble Deep Field, Williams et al. 1996).
  • Figure 3: $I$-band Subaru images centered on the location of each of the 9 IfA Deep Survey SNID-confirmed SNe Ia (indicated with a circle), taken as close to peak brightness as possible. Images are $20"$ on a side. North is up and East to the left.
  • Figure 4: $I$-band Subaru images centered on the location of each of the 14 additional SNe Ia (indicated with a circle), taken as close to peak brightness as possible. Images are $20"$ on a side. North is up and East to the left.
  • Figure 5: Spectra of the 9 SNe with spectral matches to local SNe Ia as determined by SNID. The spectra have been smoothed by taking a weighted median of FWHM 80 Å. Both spectra and template are shown as F$_{\lambda}$. Observed wavelength is indicated along top of graphs, with all wavelengths given in angstroms.
  • ...and 7 more figures