Constraining Cosmic Evolution of Type Ia Supernovae

We present a large-scale effort of creating composite spectra of high-redshift SNe Ia and comparing them to low-redshift counterparts in an attempt to understand possible cosmic evolution of SNe Ia, which has major implications for studies of dark energy. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe Ia through a multiple-decade effort at the Lick and Keck Observatories, and we have used 45 UV spectra obtained by HST and IUE. The low-redshift spectra act as a control sample when comparing to the ESSENCE spectra. In all instances, the ESSENCE and Lick composite spectra appear very similar. The addition of galaxy light to the Lick composite spectra allows an excellent match of the overall SED with the ESSENCE composite spectra, indicating that the high-redshift SNe are more contaminated with host galaxy light than their low-redshift counterparts. This is caused by observing objects at all redshifts with similar angular slit widths, which corresponds to different projected physical distances. After correcting for the galaxy light contamination, a few marginally significant differences in the spectra remain. We have estimated the systematic errors when using current spectral templates for K-corrections to be ~0.02 mag. The variance in the composite spectra gives an estimate of the intrinsic variance in low-redshift maximum light SN spectra of ~3% relative flux in the optical and growing toward the UV. The difference between the maximum light low- and high-redshift spectra constrains the evolution of SN spectral features between our samples to be <10% relative flux in the rest-frame optical. Currently, galaxy contamination and the small samples of rest-frame UV spectra at low and high redshifts are the limiting factors for future studies.

[1]  William Press,et al.  A Precise Distance Indicator: Type Ia Supernova Multicolor Light-Curve Shapes , 1996, astro-ph/9604143.

[2]  G. Graves,et al.  OPTICAL SPECTROSCOPY OF TYPE Ia SUPERNOVAE , 2008, The Astronomical Journal.

[3]  SUPERNOVA 1983G AND THE DISTANCE TO NGC 4753. , 1985 .

[4]  Berkeley,et al.  SNLS Spectroscopy: Testing for Evolution in Type Ia Supernovae , 2007, 0709.0859.

[5]  N. B. Suntzeff,et al.  Observational Constraints on the Nature of Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey , 2007, astro-ph/0701041.

[6]  M. Phillips,et al.  Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant , 1998, astro-ph/9805201.

[7]  R. Ellis,et al.  Verifying the Cosmological Utility of Type Ia Supernovae: Implications of a Dispersion in the Ultraviolet Spectra , 2007, 0710.3896.

[8]  BVRI Light Curves for 29 Type Ia Supernovae , 1996, astro-ph/9609064.

[9]  D. Schlegel,et al.  The peculiar type Ia SN 1991T : detonation of a white dwarf ? , 1992 .

[10]  Harry L. Shipman,et al.  White Dwarfs: Cosmological and Galactic Probes , 2005 .

[11]  F. Timmes,et al.  TO APPEAR IN THE ASTROPHYSICAL JOURNAL LETTERS Preprint typeset using LATEX style emulateapj v. 3/3/03 ON VARIATIONS IN THE PEAK LUMINOSITY OF TYPE IA SUPERNOVAE , 2003 .

[12]  J. Wheeler,et al.  Type Ia Supernovae: Influence of the Initial Composition on the Nucleosynthesis, Light Curves, and Spectra and Consequences for the Determination of ΩM and Λ , 1997, astro-ph/9709233.

[13]  Stefano Casertano,et al.  New Hubble Space Telescope Discoveries of Type Ia Supernovae at z ≥ 1: Narrowing Constraints on the Early Behavior of Dark Energy , 2006, astro-ph/0611572.

[14]  N. B. Suntzeff,et al.  The ESSENCE Supernova Survey: Survey Optimization, Observations, and Supernova Photometry , 2007, astro-ph/0701043.

[15]  A. S. Fruchter,et al.  Timescale Stretch Parameterization of Type Ia Supernova B-Band Light Curves , 2001, astro-ph/0104382.

[16]  COSMOLOGICAL IMPLICATIONS FROM OBSERVATIONS OF TYPE IA SUPERNOVAE , 2001 .

[17]  L. Ho,et al.  The subluminous spectroscopically peculiar type Ia supernova 1991bg in the elliptical galaxy NGC 4374 , 1992 .

[18]  J. Tonry,et al.  Determining the Type, Redshift, and Age of a Supernova Spectrum , 2006, astro-ph/0612512.

[19]  D. Branch,et al.  On the spectrum of the peculiar type Ia supernova 1997br and the nature of SN 1991T-like events , 2002 .

[20]  Thomas Matheson,et al.  Optical Spectroscopy of Type Ib/c Supernovae , 2001, astro-ph/0101119.

[21]  P. Nugent,et al.  Metallicity Effects in Non-LTE Model Atmospheres of Type Ia Supernovae , 1999, astro-ph/9906016.

[22]  B. Efron.  The jackknife, the bootstrap, and other resampling plans , 1987 .

[23]  A. V. Filippenko,et al.  THE IMPORTANCE OF ATMOSPHERIC DIFFERENTIAL REFRACTION IN SPECTROPHOTOMETRY. , 1982 .

[24]  J. Mathis,et al.  The relationship between infrared, optical, and ultraviolet extinction , 1989 .

[25]  P. Nugent,et al.  K‐Corrections and Extinction Corrections for Type Ia Supernovae , 2002, astro-ph/0205351.

[26]  A Definitive Measurement of Time Dilation in the Spectral Evolution of the Moderate-Redshift Type Ia Supernova 1997ex , 2005, astro-ph/0504481.

[27]  R. Nichol,et al.  Distributions of Galaxy Spectral Types in the Sloan Digital Sky Survey , 2004, astro-ph/0407061.

[29]  J. Neill,et al.  Gemini Spectroscopy of Supernovae from the Supernova Legacy Survey: Improving High-Redshift Supernova Selection and Classification , 2005, astro-ph/0509195.

[30]  et al,et al.  UBVRI Light Curves of 44 Type Ia Supernovae , 2005 .

[31]  Detailed analysis of early to late-time spectra of supernova 1993j , 2000, astro-ph/0006264.

[32]  Adam G. Riess,et al.  BVRI Light Curves for 22 Type Ia Supernovae , 1998 .

[33]  Old galaxies in the young Universe , 2004, Nature.

[34]  Spectra of high-redshift type Ia supernovae and a comparison with their low-redshift counterparts , 2005, astro-ph/0509041.

[35]  R. Kirshner,et al.  Analysis of the photospheric epoch spectra of type 1a supernovae SN 1990N and SN 1991T , 1992 .

[36]  D. Branch,et al.  On the ultraviolet spectra of Type I supernovae , 1986 .

[37]  R. Ellis,et al.  The Rise Time of Type Ia Supernovae from the Supernova Legacy Survey , 2006, astro-ph/0607363.

[38]  The effects of Fe II non-LTE on nova atmospheres and spectra , 1996, astro-ph/9601149.

[39]  Adam G. Riess,et al.  Improved Distances to Type Ia Supernovae with Multicolor Light-Curve Shapes: MLCS2k2 , 2006 .

[40]  Spectral diversity of Type Ia Supernovae , 2006, astro-ph/0605147.

[41]  P. Berlind,et al.  Chemistry and Star Formation in the Host Galaxies of Type Ia Supernovae , 2005 .

[42]  L. Bildsten,et al.  The Type Ia Supernova Rate , 2005, astro-ph/0507456.

[43]  Claudia Winge,et al.  SN 1992A : ultraviolet and optical studies based on HST, IUE and CTIO observations , 1993 .

[44]  M. S. Burns,et al.  Quantitative comparison between Type Ia supernova spectra at low and high redshifts: A case study , 2007, astro-ph/0703629.

[45]  A. Oemler,et al.  Type I supernovae come from short-lived stars , 1979 .

[46]  W. M. Wood-Vasey,et al.  Using Line Profiles to Test the Fraternity of Type Ia Supernovae at High and Low Redshifts , 2005, astro-ph/0510089.

[47]  Constraints on the Progenitors of Type Ia Supernovae and Implications for the Cosmological Equation of State , 2001, astro-ph/0104257.

[48]  M. Turatto,et al.  THE TYPE IA SUPERNOVA 1994D IN NGC 4526 : THE EARLY PHASES , 1996 .

[49]  L. Marschall,et al.  UBVRI Photometry of the Type Ia SN 1994D in NGC 4526 , 1995 .

[50]  J. Walsh,et al.  Extracting clean supernova spectra - Towards a quantitative analysis of high-redshift Type Ia supernova spectra , 2004, astro-ph/0410406.

[51]  The Case against the progenitor's carbon - to - oxygen ratio as a source of peak luminosity variations in Type Ia supernovae , 2004, astro-ph/0403509.

[52]  E. I. Robson,et al.  The Type IA Supernova 1989B in NGC 3627 (M66) , 1994 .

[53]  K. L. Page,et al.  Ultraviolet, Optical and X-ray Observations of the Type 1a Supernova 2005am with Swift , 2005 .

[54]  M. Phillips,et al.  Evidence for a Spectroscopic Sequence among Type Ia Supernovae , 1995, astro-ph/9510004.

[55]  F. Mannucci,et al.  The Supernova rate per unit mass , 2004, astro-ph/0411450.

[56]  Kevin Krisciunas,et al.  Hubble Space Telescope Observations of Nine High-Redshift ESSENCE Supernovae,, , 2005, astro-ph/0508681.

[57]  Ion Signatures in Supernova Spectra , 1998, astro-ph/9809236.

[58]  R. Ellis,et al.  Measurements of $\Omega$ and $\Lambda$ from 42 high redshift supernovae , 1998, astro-ph/9812133.

[59]  R. Ellis,et al.  Rates and Properties of Type Ia Supernovae as a Function of Mass and Star Formation in Their Host Galaxies , 2006, astro-ph/0605455.

[60]  P. E. Nugent,et al.  K-corrections and spectral templates of Type Ia supernovae , 2007 .

[61]  Mark Sullivan,et al.  Predicted and Observed Evolution in the Mean Properties of Type Ia Supernovae with Redshift , 2007 .

[62]  A. Kim,et al.  A GENERALIZED K CORRECTION FOR TYPE IA SUPERNOVAE: COMPARING R-BAND PHOTOMETRY BEYOND Z=0.2 WITH B, V, AND R-BAND NEARBY PHOTOMETRY , 1996 .

[63]  M. Phillips,et al.  The Absolute Magnitudes of Type IA Supernovae , 1993 .