A Caltech Library Service

Euclid preparation. V. Predicted yield of redshift 7 < z < 9 quasars from the wide survey

Barnett, R. and Warren, S. J. and Mortlock, D. J. and Cuby, J.-G. and Conselice, C. and Hewett, P. C. and Willott, C. J. and Auricchio, N. and Balaguera-Antolínez, A. and Baldi, M. and Bardelli, S. and Bellagamba, F. and Bender, R. and Biviano, A. and Bonino, D. and Bozzo, E. and Branchini, E. and Brescia, M. and Brinchmann, J. and Burigana, C. and Camera, S. and Capobianco, V. and Carbone, C. and Carretero, J. and Carvalho, C. S. and Castander, F. J. and Castellano, M. and Cavuoti, S. and Cimatti, A. and Clédassou, R. and Congedo, G. and Conversi, L. and Copin, Y. and Corcione, L. and Coupon, J. and Courtois, H. M. and Cropper, M. and Da Silva, A. and Duncan, C. A. J. and Dusini, S. and Ealet, A. and Farrens, S. and Fosalba, P. and Fotopoulou, S. and Fourmanoit, N. and Frailis, M. and Fumana, M. and Galeotta, S. and Garilli, B. and Gillard, W. and Gillis, B. R. and Graciá-Carpio, J. and Grupp, F. and Hoekstra, H. and Hormuth, F. and Israel, H. and Jahnke, K. and Kermiche, S. and Kilbinger, M. and Kirkpatrick, C. C. and Kitching, T. and Kohley, R. and Kubik, B. and Kunz, M. and Kurki-Suonio, H. and Laureijs, R. and Ligori, S. and Lilje, P. B. and Lloro, I. and Maiorano, E. and Mansutti, O. and Marggraf, O. and Martinet, N. and Marulli, F. and Massey, R. and Mauri, N. and Medinaceli, E. and Mei, S. and Mellier, Y. and Metcalf, R. B. and Metge, J. J. and Meylan, G. and Moresco, M. and Moscardini, L. and Munari, E. and Neissner, C. and Niemi, S. M. and Nutma, T. and Padilla, C. and Paltani, S. and Pasian, F. and Paykari, P. and Percival, W. J. and Pettorino, V. and Polenta, G. and Poncet, M. and Pozzetti, L. and Raison, F. and Renzi, A. and Rhodes, J. and Rix, H.-W. and Romelli, E. and Roncarelli, M. and Rossetti, E. and Saglia, R. and Sapone, D. and Scaramella, R. and Schneider, P. and Scottez, V. and Secroun, A. and Serrano, S. and Sirri, G. and Stanco, L. and Sureau, F. and Tallada-Crespí, P. and Tavagnacco, D. and Taylor, A. N. and Tenti, M. and Tereno, I. and Toledo-Moreo, R. and Torradeflot, F. and Valenziano, L. and Vassallo, T. and Wang, Y. and Zacchei, A. and Zamorani, G. and Zoubian, J. and Zucca, E. (2019) Euclid preparation. V. Predicted yield of redshift 7 < z < 9 quasars from the wide survey. Astronomy and Astrophysics, 631 . Art. No. A85. ISSN 0004-6361. doi:10.1051/0004-6361/201936427.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Accepted Version
See Usage Policy.


Use this Persistent URL to link to this item:


We provide predictions of the yield of 7 <  z <  9 quasars from the Euclid wide survey, updating the calculation presented in the Euclid Red Book in several ways. We account for revisions to the Euclid near-infrared filter wavelengths; we adopt steeper rates of decline of the quasar luminosity function (QLF; Φ) with redshift, Φ ∝ 10^(k(z − 6)), k = −0.72, and a further steeper rate of decline, k = −0.92; we use better models of the contaminating populations (MLT dwarfs and compact early-type galaxies); and we make use of an improved Bayesian selection method, compared to the colour cuts used for the Red Book calculation, allowing the identification of fainter quasars, down to J_(AB) ∼ 23. Quasars at z >  8 may be selected from Euclid OYJH photometry alone, but selection over the redshift interval 7 <  z <  8 is greatly improved by the addition of z-band data from, e.g., Pan-STARRS and LSST. We calculate predicted quasar yields for the assumed values of the rate of decline of the QLF beyond z = 6. If the decline of the QLF accelerates beyond z = 6, with k = −0.92, Euclid should nevertheless find over 100 quasars with 7.0 <  z <  7.5, and ∼25 quasars beyond the current record of z = 7.5, including ∼8 beyond z = 8.0. The first Euclid quasars at z >  7.5 should be found in the DR1 data release, expected in 2024. It will be possible to determine the bright-end slope of the QLF, 7 <  z <  8, M₁₄₅₀ <  −25, using 8 m class telescopes to confirm candidates, but follow-up with JWST or E-ELT will be required to measure the faint-end slope. Contamination of the candidate lists is predicted to be modest even at J_(AB) ∼ 23. The precision with which k can be determined over 7 <  z <  8 depends on the value of k, but assuming k = −0.72 it can be measured to a 1σ uncertainty of 0.07.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Rhodes, J.0000-0002-4485-8549
Additional Information:© 2019 ESO. Article published by EDP Sciences. Received 1 August 2019; Accepted 16 September 2019; Published online 25 October 2019. We would like to acknowledge the anonymous A&A referee, who provided useful and detailed comments on this manuscript. The Euclid internal referees were Francisco Castander and Johan Fynbo, whose reports led to several improvements in the presentation of this paper. We are also grateful to several members of the Euclid Primeval Universe Science Working Group, who provided comprehensive comments and suggestions for this work, which have led to significant changes in the analysis and discussion: Rebecca Bowler; Peter Capak; Pratika Dayal; Andrea Ferrara; Kari Helgason; and Michael Strauss. We would additionally like to thank Konrad Kuijken and Jean-Charles Cuillandre for their advice on Pan-STARRS. The Euclid Consortium acknowledges the European Space Agency and the support of a number of agencies and institutes that have supported the development of Euclid. A detailed complete list is available on the Euclid web site ( In particular the Academy of Finland, the Agenzia Spaziale Italiana, the Belgian Science Policy, the Canadian Euclid Consortium, the Centre National d’Etudes Spatiales, the Deutsches Zentrum für Luft- and Raumfahrt, the Danish Space Research Institute, the Fundação para a Ciênca e a Tecnologia, the Ministerio de Economia y Competitividad, the National Aeronautics and Space Administration, the Netherlandse Onderzoekschool Voor Astronomie, the Norvegian Space Center, the Romanian Space Agency, the State Secretariat for Education, Research and Innovation (SERI) at the Swiss Space Office (SSO), and the United Kingdom Space Agency. This work was supported by grant ST/N000838/1 from the Science and Technology Facilities Council. This research has benefitted from the SpeX Prism Spectral Libraries, maintained by Adam Burgasser at
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
European Space Agency (ESA)UNSPECIFIED
Academy of FinlandUNSPECIFIED
Agenzia Spaziale Italiana (ASI)UNSPECIFIED
Belgian Federal Science Policy Office (BELSPO)UNSPECIFIED
Canadian Euclid ConsortiumUNSPECIFIED
Centre National d’Études Spatiales (CNES)UNSPECIFIED
Deutsches Zentrum für Luft- und Raumfahrt (DLR)UNSPECIFIED
Danish Space Research InstituteUNSPECIFIED
Fundação para a Ciência e a Tecnologia (FCT)UNSPECIFIED
Ministerio de Economia y Competitividad (MINECO)UNSPECIFIED
Nederlandse Onderzoekschool Voor Astronomie (NOVA)UNSPECIFIED
Norwegian Space AgencyUNSPECIFIED
Romanian Space AgencyUNSPECIFIED
State Secretariat for Education, Research and Innovation (SERI)UNSPECIFIED
Swiss Space Office (SSO)UNSPECIFIED
United Kingdom Space Agency (UKSA)UNSPECIFIED
Science and Technology Facilities Council (STFC)ST/N000838/1
Subject Keywords:quasars: general – methods: statistical – surveys
Record Number:CaltechAUTHORS:20200309-144823827
Persistent URL:
Official Citation:Euclid preparation - V. Predicted yield of redshift 7 < z < 9 quasars from the wide survey. Euclid Collaboration, R. Barnett, S. J. Warren, D. J. Mortlock, J.-G. Cuby, C. Conselice, P. C. Hewett, C. J. Willott, N. Auricchio, A. Balaguera-Antolínez, M. Baldi, S. Bardelli, F. Bellagamba, R. Bender, A. Biviano, D. Bonino, E. Bozzo, E. Branchini, M. Brescia, J. Brinchmann, C. Burigana, S. Camera, V. Capobianco, C. Carbone, J. Carretero, C. S. Carvalho, F. J. Castander, M. Castellano, S. Cavuoti, A. Cimatti, R. Clédassou, G. Congedo, L. Conversi, Y. Copin, L. Corcione, J. Coupon, H. M. Courtois, M. Cropper, A. Da Silva, C. A. J. Duncan, S. Dusini, A. Ealet, S. Farrens, P. Fosalba, S. Fotopoulou, N. Fourmanoit, M. Frailis, M. Fumana, S. Galeotta, B. Garilli, W. Gillard, B. R. Gillis, J. Graciá-Carpio, F. Grupp, H. Hoekstra, F. Hormuth, H. Israel, K. Jahnke, S. Kermiche, M. Kilbinger, C. C. Kirkpatrick, T. Kitching, R. Kohley, B. Kubik, M. Kunz, H. Kurki-Suonio, R. Laureijs, S. Ligori, P. B. Lilje, I. Lloro, E. Maiorano, O. Mansutti, O. Marggraf, N. Martinet, F. Marulli, R. Massey, N. Mauri, E. Medinaceli, S. Mei, Y. Mellier, R. B. Metcalf, J. J. Metge, G. Meylan, M. Moresco, L. Moscardini, E. Munari, C. Neissner, S. M. Niemi, T. Nutma, C. Padilla, S. Paltani, F. Pasian, P. Paykari, W. J. Percival, V. Pettorino, G. Polenta, M. Poncet, L. Pozzetti, F. Raison, A. Renzi, J. Rhodes, H.-W. Rix, E. Romelli, M. Roncarelli, E. Rossetti, R. Saglia, D. Sapone, R. Scaramella, P. Schneider, V. Scottez, A. Secroun, S. Serrano, G. Sirri, L. Stanco, F. Sureau, P. Tallada-Crespí, D. Tavagnacco, A. N. Taylor, M. Tenti, I. Tereno, R. Toledo-Moreo, F. Torradeflot, L. Valenziano, T. Vassallo, Y. Wang, A. Zacchei, G. Zamorani, J. Zoubian and E. Zucca. A&A, 631 (2019) A85; DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:101794
Deposited By: Tony Diaz
Deposited On:09 Mar 2020 23:08
Last Modified:16 Nov 2021 18:05

Repository Staff Only: item control page