Photometric redshifts of quasars

Gordon T. Richards; Michael A. Weinstein; Donald P. Schneider; Xiaohui Fan; Michael A. Strauss; Daniel E. Vanden Berk; James Annis; Scott Burles; Emily M. Laubacher; Donald G. York; Joshua A. Frieman; David Johnston; Ryan Scranton; James E. Gunn; Željko Ivezić; R. C. Nichol; Tamás Budavári; István Csabai; Alexander S. Szalay; Andrew J. Connolly; Gyula P. Szokoly; Neta A. Bahcall; Narciso Benítez; J. Brinkmann; Robert Brunner; Masataka Fukugita; Patrick B. Hall; G. S. Hennessy; G. R. Knapp; Peter Z. Kunszt; D. Q. Lamb; Jeffrey A. Munn; Heidi J.O. Newberg; Chris Stoughton

doi:10.1086/322132

Photometric redshifts of quasars

Gordon T. Richards, Michael A. Weinstein, Donald P. Schneider, Xiaohui Fan, Michael A. Strauss, Daniel E. Vanden Berk, James Annis, Scott Burles, Emily M. Laubacher, Donald G. York, Joshua A. Frieman, David Johnston, Ryan Scranton, James E. Gunn, Željko Ivezić, R. C. Nichol, Tamás Budavári, István Csabai, Alexander S. Szalay, Andrew J. ConnollyGyula P. Szokoly, Neta A. Bahcall, Narciso Benítez, J. Brinkmann, Robert Brunner, Masataka Fukugita, Patrick B. Hall, G. S. Hennessy, G. R. Knapp, Peter Z. Kunszt, D. Q. Lamb, Jeffrey A. Munn, Heidi J.O. Newberg, Chris Stoughton

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90 Scopus citations

Abstract

We demonstrate that the design of the Sloan Digital Sky Survey (SDSS) filter system and the quality of the SDSS imaging data are sufficient for determining accurate and precise photometric redshifts of quasars. Using a sample of 2625 quasars, we show that "photo-z" determination is even possible for z ≤ 2.2 despite the lack of a strong continuum break, which robust photo-z techniques normally require. We find that, using our empirical method on our sample of objects known to be quasars, approximately 70% of the photometric redshifts are correct to within Δz = 0.2; the fraction of correct photometric redshifts is even better for z > 3. The accuracy of quasar photometric redshifts does not appear to be dependent upon magnitude to nearly 21st magnitude in i′. Careful calibration of the color-redshift relation to 21st magnitude may allow for the discovery of ∼10⁶ quasar candidates in addition to the 10⁵ quasars that the SDSS will confirm spectroscopically. We discuss the efficient selection of quasar candidates from imaging data for use with the photometric redshift technique and the potential scientific uses of a large sample of quasar candidates with photometric redshifts.

Original language	English (US)
Pages (from-to)	1151-1162
Number of pages	12
Journal	Astronomical Journal
Volume	122
Issue number	3
DOIs	https://doi.org/10.1086/322132
State	Published - Sep 2001

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

Galaxies: distances and redshifts
Galaxies: photometry
Methods: statistical
Quasars: general

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10.1086/322132

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Richards, G. T., Weinstein, M. A., Schneider, D. P., Fan, X., Strauss, M. A., Vanden Berk, D. E., Annis, J., Burles, S., Laubacher, E. M., York, D. G., Frieman, J. A., Johnston, D., Scranton, R., Gunn, J. E., Ivezić, Ž., Nichol, R. C., Budavári, T., Csabai, I., Szalay, A. S., ... Stoughton, C. (2001). Photometric redshifts of quasars. Astronomical Journal, 122(3), 1151-1162. https://doi.org/10.1086/322132

@article{0f1eba40e7e347018810a457abea16f6,

title = "Photometric redshifts of quasars",

abstract = "We demonstrate that the design of the Sloan Digital Sky Survey (SDSS) filter system and the quality of the SDSS imaging data are sufficient for determining accurate and precise photometric redshifts of quasars. Using a sample of 2625 quasars, we show that {"}photo-z{"} determination is even possible for z ≤ 2.2 despite the lack of a strong continuum break, which robust photo-z techniques normally require. We find that, using our empirical method on our sample of objects known to be quasars, approximately 70% of the photometric redshifts are correct to within Δz = 0.2; the fraction of correct photometric redshifts is even better for z > 3. The accuracy of quasar photometric redshifts does not appear to be dependent upon magnitude to nearly 21st magnitude in i′. Careful calibration of the color-redshift relation to 21st magnitude may allow for the discovery of ∼106 quasar candidates in addition to the 105 quasars that the SDSS will confirm spectroscopically. We discuss the efficient selection of quasar candidates from imaging data for use with the photometric redshift technique and the potential scientific uses of a large sample of quasar candidates with photometric redshifts.",

keywords = "Galaxies: distances and redshifts, Galaxies: photometry, Methods: statistical, Quasars: general",

author = "Richards, {Gordon T.} and Weinstein, {Michael A.} and Schneider, {Donald P.} and Xiaohui Fan and Strauss, {Michael A.} and {Vanden Berk}, {Daniel E.} and James Annis and Scott Burles and Laubacher, {Emily M.} and York, {Donald G.} and Frieman, {Joshua A.} and David Johnston and Ryan Scranton and Gunn, {James E.} and {\v Z}eljko Ivezi{\'c} and Nichol, {R. C.} and Tam{\'a}s Budav{\'a}ri and Istv{\'a}n Csabai and Szalay, {Alexander S.} and Connolly, {Andrew J.} and Szokoly, {Gyula P.} and Bahcall, {Neta A.} and Narciso Ben{\'i}tez and J. Brinkmann and Robert Brunner and Masataka Fukugita and Hall, {Patrick B.} and Hennessy, {G. S.} and Knapp, {G. R.} and Kunszt, {Peter Z.} and Lamb, {D. Q.} and Munn, {Jeffrey A.} and Newberg, {Heidi J.O.} and Chris Stoughton",

year = "2001",

month = sep,

doi = "10.1086/322132",

language = "English (US)",

volume = "122",

pages = "1151--1162",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "IOP Publishing Ltd.",

number = "3",

}

Richards, GT, Weinstein, MA, Schneider, DP, Fan, X, Strauss, MA, Vanden Berk, DE, Annis, J, Burles, S, Laubacher, EM, York, DG, Frieman, JA, Johnston, D, Scranton, R, Gunn, JE, Ivezić, Ž, Nichol, RC, Budavári, T, Csabai, I, Szalay, AS, Connolly, AJ, Szokoly, GP, Bahcall, NA, Benítez, N, Brinkmann, J, Brunner, R, Fukugita, M, Hall, PB, Hennessy, GS, Knapp, GR, Kunszt, PZ, Lamb, DQ, Munn, JA, Newberg, HJO & Stoughton, C 2001, 'Photometric redshifts of quasars', Astronomical Journal, vol. 122, no. 3, pp. 1151-1162. https://doi.org/10.1086/322132

TY - JOUR

T1 - Photometric redshifts of quasars

AU - Richards, Gordon T.

AU - Weinstein, Michael A.

AU - Schneider, Donald P.

AU - Fan, Xiaohui

AU - Strauss, Michael A.

AU - Vanden Berk, Daniel E.

AU - Annis, James

AU - Burles, Scott

AU - Laubacher, Emily M.

AU - York, Donald G.

AU - Frieman, Joshua A.

AU - Johnston, David

AU - Scranton, Ryan

AU - Gunn, James E.

AU - Ivezić, Željko

AU - Nichol, R. C.

AU - Budavári, Tamás

AU - Csabai, István

AU - Szalay, Alexander S.

AU - Connolly, Andrew J.

AU - Szokoly, Gyula P.

AU - Bahcall, Neta A.

AU - Benítez, Narciso

AU - Brinkmann, J.

AU - Brunner, Robert

AU - Fukugita, Masataka

AU - Hall, Patrick B.

AU - Hennessy, G. S.

AU - Knapp, G. R.

AU - Kunszt, Peter Z.

AU - Lamb, D. Q.

AU - Munn, Jeffrey A.

AU - Newberg, Heidi J.O.

AU - Stoughton, Chris

PY - 2001/9

Y1 - 2001/9

N2 - We demonstrate that the design of the Sloan Digital Sky Survey (SDSS) filter system and the quality of the SDSS imaging data are sufficient for determining accurate and precise photometric redshifts of quasars. Using a sample of 2625 quasars, we show that "photo-z" determination is even possible for z ≤ 2.2 despite the lack of a strong continuum break, which robust photo-z techniques normally require. We find that, using our empirical method on our sample of objects known to be quasars, approximately 70% of the photometric redshifts are correct to within Δz = 0.2; the fraction of correct photometric redshifts is even better for z > 3. The accuracy of quasar photometric redshifts does not appear to be dependent upon magnitude to nearly 21st magnitude in i′. Careful calibration of the color-redshift relation to 21st magnitude may allow for the discovery of ∼106 quasar candidates in addition to the 105 quasars that the SDSS will confirm spectroscopically. We discuss the efficient selection of quasar candidates from imaging data for use with the photometric redshift technique and the potential scientific uses of a large sample of quasar candidates with photometric redshifts.

AB - We demonstrate that the design of the Sloan Digital Sky Survey (SDSS) filter system and the quality of the SDSS imaging data are sufficient for determining accurate and precise photometric redshifts of quasars. Using a sample of 2625 quasars, we show that "photo-z" determination is even possible for z ≤ 2.2 despite the lack of a strong continuum break, which robust photo-z techniques normally require. We find that, using our empirical method on our sample of objects known to be quasars, approximately 70% of the photometric redshifts are correct to within Δz = 0.2; the fraction of correct photometric redshifts is even better for z > 3. The accuracy of quasar photometric redshifts does not appear to be dependent upon magnitude to nearly 21st magnitude in i′. Careful calibration of the color-redshift relation to 21st magnitude may allow for the discovery of ∼106 quasar candidates in addition to the 105 quasars that the SDSS will confirm spectroscopically. We discuss the efficient selection of quasar candidates from imaging data for use with the photometric redshift technique and the potential scientific uses of a large sample of quasar candidates with photometric redshifts.

KW - Galaxies: distances and redshifts

KW - Galaxies: photometry

KW - Methods: statistical

KW - Quasars: general

UR - http://www.scopus.com/inward/record.url?scp=18044374160&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=18044374160&partnerID=8YFLogxK

U2 - 10.1086/322132

DO - 10.1086/322132

M3 - Article

AN - SCOPUS:18044374160

SN - 0004-6256

VL - 122

SP - 1151

EP - 1162

JO - Astronomical Journal

JF - Astronomical Journal

IS - 3

ER -

Photometric redshifts of quasars

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