# TYPE Ia SUPERNOVA DISTANCE MODULUS BIAS AND DISPERSION FROM K-CORRECTION ERRORS: A DIRECT MEASUREMENT USING LIGHT CURVE FITS TO OBSERVED SPECTRAL TIME SERIES

## Abstract

We estimate systematic errors due to K-corrections in standard photometric analyses of high-redshift Type Ia supernovae. Errors due to K-correction occur when the spectral template model underlying the light curve fitter poorly represents the actual supernova spectral energy distribution, meaning that the distance modulus cannot be recovered accurately. In order to quantify this effect, synthetic photometry is performed on artificially redshifted spectrophotometric data from 119 low-redshift supernovae from the Nearby Supernova Factory, and the resulting light curves are fit with a conventional light curve fitter. We measure the variation in the standardized magnitude that would be fit for a given supernova if located at a range of redshifts and observed with various filter sets corresponding to current and future supernova surveys. We find significant variation in the measurements of the same supernovae placed at different redshifts regardless of filters used, which causes dispersion greater than ∼0.05 mag for measurements of photometry using the Sloan-like filters and a bias that corresponds to a 0.03 shift in w when applied to an outside data set. To test the result of a shift in supernova population or environment at higher redshifts, we repeat our calculations with the addition of a reweighting of themore »

- Authors:
- more »

- Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
- Laboratoire de Physique Nucléaire et des Hautes Énergies, Université Pierre et Marie Curie Paris 6, Université Paris Diderot Paris 7, CNRS-IN2P3, 4 Place Jussieu, F-75252 Paris Cedex 05 (France)
- Department of Physics, Yale University, New Haven, CT 06250-8121 (United States)
- Université de Lyon, Université Lyon 1, CNRS/IN2P3, Institut de Physique Nucléaire de Lyon, 69622 Villeurbanne (France)
- Physikalisches Institut, Universität Bonn, Nußallee 12, D-53115 Bonn (Germany)

- Publication Date:

- OSTI Identifier:
- 22364212

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Astrophysical Journal; Journal Volume: 800; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CORRECTIONS; COSMOLOGY; DIAGRAMS; DISTANCE; ENERGY SPECTRA; PHOTOMETRY; RED SHIFT; SPECTROPHOTOMETRY; STAR MODELS; SUPERNOVAE; VARIATIONS; VISIBLE RADIATION

### Citation Formats

```
Saunders, C., Aldering, G., Aragon, C., Bailey, S., Childress, M., Fakhouri, H. K., Kim, A. G., Antilogus, P., Bongard, S., Canto, A., Cellier-Holzem, F., Guy, J., Baltay, C., Buton, C., Chotard, N., Copin, Y., Gangler, E., Feindt, U., Kerschhaggl, M., Kowalski, M., and and others.
```*TYPE Ia SUPERNOVA DISTANCE MODULUS BIAS AND DISPERSION FROM K-CORRECTION ERRORS: A DIRECT MEASUREMENT USING LIGHT CURVE FITS TO OBSERVED SPECTRAL TIME SERIES*. United States: N. p., 2015.
Web. doi:10.1088/0004-637X/800/1/57.

```
Saunders, C., Aldering, G., Aragon, C., Bailey, S., Childress, M., Fakhouri, H. K., Kim, A. G., Antilogus, P., Bongard, S., Canto, A., Cellier-Holzem, F., Guy, J., Baltay, C., Buton, C., Chotard, N., Copin, Y., Gangler, E., Feindt, U., Kerschhaggl, M., Kowalski, M., & and others.
```*TYPE Ia SUPERNOVA DISTANCE MODULUS BIAS AND DISPERSION FROM K-CORRECTION ERRORS: A DIRECT MEASUREMENT USING LIGHT CURVE FITS TO OBSERVED SPECTRAL TIME SERIES*. United States. doi:10.1088/0004-637X/800/1/57.

```
Saunders, C., Aldering, G., Aragon, C., Bailey, S., Childress, M., Fakhouri, H. K., Kim, A. G., Antilogus, P., Bongard, S., Canto, A., Cellier-Holzem, F., Guy, J., Baltay, C., Buton, C., Chotard, N., Copin, Y., Gangler, E., Feindt, U., Kerschhaggl, M., Kowalski, M., and and others. Tue .
"TYPE Ia SUPERNOVA DISTANCE MODULUS BIAS AND DISPERSION FROM K-CORRECTION ERRORS: A DIRECT MEASUREMENT USING LIGHT CURVE FITS TO OBSERVED SPECTRAL TIME SERIES". United States.
doi:10.1088/0004-637X/800/1/57.
```

```
@article{osti_22364212,
```

title = {TYPE Ia SUPERNOVA DISTANCE MODULUS BIAS AND DISPERSION FROM K-CORRECTION ERRORS: A DIRECT MEASUREMENT USING LIGHT CURVE FITS TO OBSERVED SPECTRAL TIME SERIES},

author = {Saunders, C. and Aldering, G. and Aragon, C. and Bailey, S. and Childress, M. and Fakhouri, H. K. and Kim, A. G. and Antilogus, P. and Bongard, S. and Canto, A. and Cellier-Holzem, F. and Guy, J. and Baltay, C. and Buton, C. and Chotard, N. and Copin, Y. and Gangler, E. and Feindt, U. and Kerschhaggl, M. and Kowalski, M. and and others},

abstractNote = {We estimate systematic errors due to K-corrections in standard photometric analyses of high-redshift Type Ia supernovae. Errors due to K-correction occur when the spectral template model underlying the light curve fitter poorly represents the actual supernova spectral energy distribution, meaning that the distance modulus cannot be recovered accurately. In order to quantify this effect, synthetic photometry is performed on artificially redshifted spectrophotometric data from 119 low-redshift supernovae from the Nearby Supernova Factory, and the resulting light curves are fit with a conventional light curve fitter. We measure the variation in the standardized magnitude that would be fit for a given supernova if located at a range of redshifts and observed with various filter sets corresponding to current and future supernova surveys. We find significant variation in the measurements of the same supernovae placed at different redshifts regardless of filters used, which causes dispersion greater than ∼0.05 mag for measurements of photometry using the Sloan-like filters and a bias that corresponds to a 0.03 shift in w when applied to an outside data set. To test the result of a shift in supernova population or environment at higher redshifts, we repeat our calculations with the addition of a reweighting of the supernovae as a function of redshift and find that this strongly affects the results and would have repercussions for cosmology. We discuss possible methods to reduce the contribution of the K-correction bias and uncertainty.},

doi = {10.1088/0004-637X/800/1/57},

journal = {Astrophysical Journal},

number = 1,

volume = 800,

place = {United States},

year = {Tue Feb 10 00:00:00 EST 2015},

month = {Tue Feb 10 00:00:00 EST 2015}

}