Selection of AGN candidates in the GOODS-South Field through Spitzer/MIPS 24 μm variability
We present a study of galaxies showing mid-infrared variability in data taken in the deepest Spitzer/MIPS 24 mu m surveys in the Great Observatory Origins Deep Survey South field. We divide the data set in epochs and subepochs to study the long-term (months-years) and the short-term (days) variabili...
| Autores: | , , , , , |
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| Tipo de documento: | artigo |
| Data de publicação: | 2015 |
| País: | España |
| Recursos: | Universidad Complutense de Madrid (UCM) |
| Repositório: | Docta Complutense |
| Idioma: | inglês |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/23014 |
| Acesso em linha: | https://hdl.handle.net/20.500.14352/23014 |
| Access Level: | Acceso aberto |
| Palavra-chave: | 52 Active galactic nuclei Star-forming galaxies Supermassive black-holes Point-source catalogs Hubble deep field X-ray sources Midinfrared selection Photometric redshifts Spectral properties Formation history Astrofísica Astronomía (Física) Física atmosférica 2501 Ciencias de la Atmósfera |
| Resumo: | We present a study of galaxies showing mid-infrared variability in data taken in the deepest Spitzer/MIPS 24 mu m surveys in the Great Observatory Origins Deep Survey South field. We divide the data set in epochs and subepochs to study the long-term (months-years) and the short-term (days) variability. We use a chi^(2)-statistics method to select active galactic nucleus (AGN) candidates with a probability <≤ 1% that the observed variability is due to statistical errors alone. We find 39 (1.7 per cent of the parent sample) sources that show long-term variability and 55 (2.2 per cent of the parent sample) showing short-term variability. That is, 0.03 sources x arcmin^(-2) for both, long-term and short-term variable sources. After removing the expected number of false positives inherent to the method, the estimated percentages are 1.0 and 1.4 per cent of the parent sample for the long term and short term, respectively. We compare our candidates with AGN selected in the X-ray and radio bands, and AGN candidates selected by their IR emission. Approximately, 50 per cent of the MIPS (Multiband Imaging Photometer for Spitzer) 24 mu m variable sources would be identified as AGN with these other methods. Therefore, MIPS 24 μm variability is a new method to identify AGN candidates, possibly dust obscured and low-luminosity AGN, that might be missed by other methods. However, the contribution of the MIPS 24 mu m variable identified AGN to the general AGN population is small (≤ 13%) in GOODS-South. |
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