Photometric SN Ia Candidates from the Three-Year SDSS-II SN Survey Data
Autor: | Sako, Masao, Bassett, Bruce, Connolly, Brian, Dilday, Benjamin, Campbell, Heather, Frieman, Joshua, Gladney, Larry, Kessler, Richard, Lampeitl, Hubert, Marriner, John, Miquel, Ramon, Nichol, Robert, Schneider, Donald, Smith, Mathew, Sollerman, Jesper |
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Rok vydání: | 2011 |
Předmět: | |
Druh dokumentu: | Working Paper |
DOI: | 10.1088/0004-637X/738/2/162 |
Popis: | We analyze the three-year SDSS-II Superernova (SN) Survey data and identify a sample of 1070 photometric SN Ia candidates based on their multi-band light curve data. This sample consists of SN candidates with no spectroscopic confirmation, with a subset of 210 candidates having spectroscopic redshifts of their host galaxies measured, while the remaining 860 candidates are purely photometric in their identification. We describe a method for estimating the efficiency and purity of photometric SN Ia classification when spectroscopic confirmation of only a limited sample is available, and demonstrate that SN Ia candidates from SDSS-II can be identified photometrically with ~91% efficiency and with a contamination of ~6%. Although this is the largest uniform sample of SN candidates to date for studying photometric identification, we find that a larger spectroscopic sample of contaminating sources is required to obtain a better characterization of the background events. A Hubble diagram using SN candidates with no spectroscopic confirmation, but with host galaxy spectroscopic redshifts, yields a distance modulus dispersion that is only ~20 - 40% larger than that of the spectroscopically-confirmed SN Ia sample alone with no significant bias. A Hubble diagram with purely photometric classification and redshift-distance measurements, however, exhibit biases that require further investigation for precision cosmology. Comment: The Astrophysical Journal (in press) |
Databáze: | arXiv |
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