Photometric redshifts from reconstructed quasar templates

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

Research output: Contribution to journalArticle

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Abstract

From Sloan Digital Sky Survey (SDSS) commissioning photometric and spectroscopic data, we investigate the utility of photometric redshift techniques in 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, because of 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 broadband photometric and spectral photometric calibrations.

Original languageEnglish (US)
Pages (from-to)1163-1171
Number of pages9
JournalAstronomical Journal
Volume122
Issue number3
DOIs
StatePublished - Sep 1 2001

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quasars
templates
photometry
polynomials
broadband
spectral energy distribution
calibration
education
estimating
energy
method

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Budavári, T., Csabai, I., Szalay, A. S., Connolly, A. J., Szokoly, G. P., Vanden Berk, D. E., ... York, D. G. (2001). Photometric redshifts from reconstructed quasar templates. Astronomical Journal, 122(3), 1163-1171. https://doi.org/10.1086/322131
Budavári, Tamás ; Csabai, István ; Szalay, Alexander S. ; Connolly, Andrew J. ; Szokoly, Gyula P. ; Vanden Berk, Daniel E. ; Richards, Gordon T. ; Weinstein, Michael A. ; Schneider, Donald P. ; Benítez, Narciso ; Brinkmann, J. ; Brunner, Robert ; Hall, Patrick B. ; Hennessy, G. S. ; Ivezić, Željko ; Kunszt, Péter Z. ; Munn, Jeffrey A. ; Nichol, R. C. ; Pier, Jeffrey R. ; York, Donald G. / Photometric redshifts from reconstructed quasar templates. In: Astronomical Journal. 2001 ; Vol. 122, No. 3. pp. 1163-1171.
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abstract = "From Sloan Digital Sky Survey (SDSS) commissioning photometric and spectroscopic data, we investigate the utility of photometric redshift techniques in 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, because of 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 broadband photometric and spectral photometric calibrations.",
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Budavári, T, Csabai, I, Szalay, AS, Connolly, AJ, Szokoly, GP, Vanden Berk, DE, Richards, GT, Weinstein, MA, Schneider, DP, Benítez, N, Brinkmann, J, Brunner, R, Hall, PB, Hennessy, GS, Ivezić, Ž, Kunszt, PZ, Munn, JA, Nichol, RC, Pier, JR & York, DG 2001, 'Photometric redshifts from reconstructed quasar templates', Astronomical Journal, vol. 122, no. 3, pp. 1163-1171. https://doi.org/10.1086/322131

Photometric redshifts from reconstructed quasar templates. / Budavári, Tamás; Csabai, István; Szalay, Alexander S.; Connolly, Andrew J.; Szokoly, Gyula P.; Vanden Berk, Daniel E.; Richards, Gordon T.; Weinstein, Michael A.; Schneider, Donald P.; Benítez, Narciso; Brinkmann, J.; Brunner, Robert; Hall, Patrick B.; Hennessy, G. S.; Ivezić, Željko; Kunszt, Péter Z.; Munn, Jeffrey A.; Nichol, R. C.; Pier, Jeffrey R.; York, Donald G.

In: Astronomical Journal, Vol. 122, No. 3, 01.09.2001, p. 1163-1171.

Research output: Contribution to journalArticle

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T1 - Photometric redshifts from reconstructed quasar templates

AU - Budavári, Tamás

AU - Csabai, István

AU - Szalay, Alexander S.

AU - Connolly, Andrew J.

AU - Szokoly, Gyula P.

AU - Vanden Berk, Daniel E.

AU - Richards, Gordon T.

AU - Weinstein, Michael A.

AU - Schneider, Donald P.

AU - Benítez, Narciso

AU - Brinkmann, J.

AU - Brunner, Robert

AU - Hall, Patrick B.

AU - Hennessy, G. S.

AU - Ivezić, Željko

AU - Kunszt, Péter Z.

AU - Munn, Jeffrey A.

AU - Nichol, R. C.

AU - Pier, Jeffrey R.

AU - York, Donald G.

PY - 2001/9/1

Y1 - 2001/9/1

N2 - From Sloan Digital Sky Survey (SDSS) commissioning photometric and spectroscopic data, we investigate the utility of photometric redshift techniques in 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, because of 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 broadband photometric and spectral photometric calibrations.

AB - From Sloan Digital Sky Survey (SDSS) commissioning photometric and spectroscopic data, we investigate the utility of photometric redshift techniques in 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, because of 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 broadband photometric and spectral photometric calibrations.

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Budavári T, Csabai I, Szalay AS, Connolly AJ, Szokoly GP, Vanden Berk DE et al. Photometric redshifts from reconstructed quasar templates. Astronomical Journal. 2001 Sep 1;122(3):1163-1171. https://doi.org/10.1086/322131