Photometric Redshifts from Reconstructed Quasar Templates
| Autor: | Tamás Budavári, István Csabai, Alexander S. Szalay, Andrew J. Connolly, Gyula P. Szokoly, Daniel E. Vanden Berk, Gordon T. Richards, Michael A. Weinstein, Donald P. Schneider, Narciso Benítez, J. Brinkmann, Robert Brunner, Patrick B. Hall, G. S. Hennessy, Željko Ivezić, Péter Z. Kunszt, Jeffrey A. Munn, R. C. Nichol, Jeffrey R. Pier, Donald G. York |
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| Rok vydání: | 2001 |
| Předmět: |
QSOS
Physics 010308 nuclear & particles physics Astrophysics (astro-ph) Astrophysics::Instrumentation and Methods for Astrophysics FOS: Physical sciences Spectral density Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics 01 natural sciences Spectral line Redshift 3. Good health Photometry (optics) Template Space and Planetary Science 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics Emission spectrum 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Photometric redshift |
| Zdroj: | ASTRONOMICAL JOURNAL Artículos CONICYT CONICYT Chile instacron:CONICYT |
| ISSN: | 0004-6256 |
| DOI: | 10.1086/322131 |
| Popis: | From SDSS commissioning photometric and spectroscopic data, we investigate the utility of photometric redshift techniques to the task of estimating QSO redshifts. We consider empirical methods (e.g. nearest-neighbor searches and polynomial fitting), standard spectral template fitting and hybrid approaches (i.e. training spectral templates from spectroscopic and photometric observations of QSOs). We find that in all cases, due to the presence of strong emission-lines within the QSO spectra, the nearest-neighbor and template fitting methods are superior to the polynomial fitting approach. Applying a novel reconstruction technique, we can, from the SDSS multicolor photometry, reconstruct a statistical representation of the underlying SEDs of the SDSS QSOs. Although, the reconstructed templates are based on only broadband photometry the common emission lines present within the QSO spectra can be recovered in the resulting spectral energy distributions. The technique should be useful in searching for spectral differences among QSOs at a given redshift, in searching for spectral evolution of QSOs, in comparing photometric redshifts for objects beyond the SDSS spectroscopic sample with those in the well calibrated photometric redshifts for objects brighter than 20th magnitude and in searching for systematic and time variable effects in the SDSS broad band photometric and spectral photometric calibrations. 21 pages, 9 figures, LaTeX AASTeX, submitted to AJ |
| Databáze: | OpenAIRE |
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