The miniJPAS and J-NEP surveys: Identification and characterization of the Lyα emitter population and the Lyα luminosity function at redshift 2.05 < z < 3.75

¹ Observatori Astronòmic de la Universitat de València, Ed. Instituts d’Investigació, Parc Científic. C/ Catedrático José Beltrán, n2, 46980 Paterna, Valencia, Spain
e-mail: alberto.torralba@uv.es
² Departament d’Astronomia i Astrofísica, Universitat de València, 46100 Burjassot, Spain
³ Department of Astronomy, MongManWai Building, Tsinghua University, Beijing 100084, PR China
⁴ Dipartimento di Fisica “G. Occhialini”, Università degli Studi di Milano-Bicocca, Università degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
⁵ INFN, Sezione di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
⁶ Instituto de Física de Cantabria (CSIC-UC), Avda. Los Castros s/n, 39005 Santander, Spain
⁷ Unidad Asociada “Grupo de Astrofísica Extragaláctica y Cosmología”, IFCA-CSIC/Universitat de València, València, Spain
⁸ Donostia International Physics Center, Paseo Manuel de Lardizabal, 4, 20018 Donostia-San Sebastián (Gipuzkoa), Spain
⁹ IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
¹⁰ Instituto de Astrofísica de Andalucía – CSIC, Apdo 3004, 18080 Granada, Spain
¹¹ Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza San Juan 1, 44001 Teruel, Spain
¹² Departamento de Física Matemática, Instituto de Física, Universidade de Saõ Paulo, Rua do Matão 1371, CEP 05508-090, São Paulo, Brazil
¹³ Observatório Nacional, Rua General é Cristino 77, São Cristóvão, 20921-400 Rio de Janeiro, RJ, Brazil
¹⁴ Instituto de Física, Universidade Federal da Bahia, 40210-340 Salvador, BA, Brazil
¹⁵ Departamento de Astronomia, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Sáo Paulo, Brazil
¹⁶ Instruments4, 4121 Pembury Place, La Canada Flintridge, CA, 91011 California, USA

Received: 14 July 2023
Accepted: 8 October 2023

Abstract

We present the Lyman-α (Lyα) luminosity function (LF) at 2.05 < z < 3.75, estimated from a sample of 67 Lyα-emitter (LAE) candidates in the Javalambre Physics of the Accelerating Universe Astronomical Survey (J-PAS) pathfinder surveys: miniJPAS and J-NEP. These two surveys cover a total effective area of ∼1.14 deg² with 54 narrow band (NB) filters (FWHM ∼ 145 Å) across the optical range, with typical limiting magnitudes of ∼23. This set of NBs allowed us to probe Lyα emission in a wide and continuous range of redshifts. We developed a method for detecting Lyα emission for the estimation of the Lyα LF using the whole J-PAS filter set. We tested this method by applying it to the miniJPAS and J-NEP data. In order to compute the corrections needed to estimate the Lyα LF and to test the performance of the candidate selection method, we built mock catalogs. These include representative populations of LAEs at 1.9 < z < 4.5 as well as their expected contaminants, namely low-z galaxies and z < 2 quasi-stellar objects (QSOs). We show that our method is able to provide the Lyα LF at the intermediate-bright range of luminosity (43.5 ≲ log₁₀(L_Lyα/erg s⁻¹) ≲ 44.5) combining both miniJPAS and J-NEP. The photometric information provided by these surveys suggests that our samples are dominated by bright, Lyα-emitting active galactic nuclei (i.e., AGNs). At log₁₀(L_Lyα/erg s⁻¹) < 44.5, we fit our Lyα LF to a power law with a slope of A = 0.70 ± 0.25. We also fit a Schechter function to our data, obtaining the following: log₁₀(Φ^∗/Mpc⁻³) = −6.30_−0.70^+0.48, log₁₀(L^∗/erg s⁻¹) = 44.85_−0.32^+0.50, and α = −1.65_−0.27^+0.29. Overall, our results confirm the presence of an AGN component at the bright end of the Lyα LF. In particular, we find no significant contribution of star-forming LAEs to the Lyα LF at log₁₀(L_Lyα/erg s⁻¹) > 43.5. This work serves as a proof of concept for the results that can be obtained with the upcoming data releases of the J-PAS survey.