Abstract
Host galaxy identification is a crucial step for modern supernova (SN) surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope, which will discover SNe by the thousands. Spectroscopic resources are limited, and so in the absence of real-time SN spectra these surveys must rely on host galaxy spectra to obtain accurate redshifts for the Hubble diagram and to improve photometric classification of SNe. In addition, SN luminosities are known to correlate with host-galaxy properties. Therefore, reliable identification of host galaxies is essential for cosmology and SN science. We simulate SN events and their locations within their host galaxies to develop and test methods for matching SNe to their hosts. We use both real and simulated galaxy catalog data from the Advanced Camera for Surveys General Catalog and MICECATv2.0, respectively. We also incorporate "hostless" SNe residing in undetected faint hosts into our analysis, with an assumed hostless rate of 5%. Our fully automated algorithm is run on catalog data and matches SNe to their hosts with 91% accuracy. We find that including a machine learning component, run after the initial matching algorithm, improves the accuracy (purity) of the matching to 97% with a 2% cost in efficiency (true positive rate). Although the exact results are dependent on the details of the survey and the galaxy catalogs used, the method of identifying host galaxies we outline here can be applied to any transient survey.
Original language | English |
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Article number | 154 |
Journal | Astronomical Journal |
Volume | 152 |
Issue number | 6 |
DOIs | |
State | Published - Dec 2016 |
Externally published | Yes |
Funding
The DES data management system is supported by the National Science Foundation under Grant Number AST- 1138766. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2012- 39559, ESP2013-48274, FPA2013-47986, and Centro de Excelencia Severo Ochoa SEV-2012-0234. Research leading to these results has received funding from the European Research Council under the European Unions Seventh Framework Programme (FP7/2007-2013) including ERC grant agreements 240672, 291329, and 306478.
Funders | Funder number |
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Centro de Excelencia Severo Ochoa | SEV-2012-0234 |
National Science Foundation | AST- 1138766 |
Seventh Framework Programme | 1138766, 240672, 615929, 306478, 291329 |
Engineering Research Centers | |
European Research Council | |
Ministerio de Economía y Competitividad | AYA2012- 39559, FPA2013-47986, ESP2013-48274 |
Seventh Framework Programme |
Keywords
- catalogs
- galaxies: general
- supernovae: general
- surveys