Volume 643, November 2020
|Number of page(s)||27|
|Published online||17 November 2020|
J-PLUS: Unveiling the brightest end of the Lyα luminosity function at 2.0 < z < 3.3 over 1000 deg2⋆
Centro de Estudios de Física del Cosmos de Aragón, Plaza San Juan 1, planta 2, 44001 Teruel, Spain
2 PlantTech Research Institute Limited, South British House, 4th Floor, 35 Grey Street, Tauranga 3110, New Zealand
3 Donostia International Physics Center, Paseo Manuel de Lardizabal, 4, 20018 Donostia-San Sebastián (Gipuzkoa), Spain
4 IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
5 Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
6 Institute for Multi-messenger Astrophysics and Cosmology, Department of Physics, Missouri University of Science and Technology, 1315 N. Pine St., Rolla, MO 65409, USA
7 Universidade de São Paulo, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, 05508090 São Paulo, SP, Brazil
8 Asociación Astrofísica para la Promoción de la Investigación, Instrumentación y su Desarrollo, 38205 La Laguna, Tenerife, Spain
9 Observatório Nacional/MCTIC, Rua José Cristino, 77, CEP 20921-400 São Cristóvão, Rio de Janeiro (RJ), Brazil
10 Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
11 Institució Catalana de Recerca i Estudis Avançats, 08034 Barcelona, Spain
12 Institute for Advanced Study, Princeton, NJ 08544, USA
13 Department of Astronomy, University of Michigan, Ann Arbor, MI 48109-1107, USA
14 Instituto de Astrofísica de Andalucía – CSIC, Apdo 3004, 18080 Granada, Spain
15 Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-970 Natal, RN, Brazil
16 Instituto Nacional de Pesquisas Espaciais. INPE/CRN, 59076-740 Natal, RN, Brazil
Accepted: 8 September 2020
We present the photometric determination of the bright end of the Lyα luminosity function (LF; at LLyα ≳ 1043.3 erg s−1) within four redshift windows (Δ z < 0.16) in the interval 2.2 ≲ z ≲ 3.3. Our work is based on the Javalambre Photometric Local Universe Survey (J-PLUS) first data release, which provides multiple narrow-band measurements over ∼1000 deg2, with limiting magnitude r ∼ 22. The analysis of high-z Lyα-emitting sources over such a wide area is unprecedented and allows us to select approximately 14 500 hyper-bright (LLyα > 1043.3 erg s−1) Lyα-emitting candidates. We test our selection with two spectroscopic programs at the GTC telescope, which confirm ∼89% of the targets as line-emitting sources, with ∼64% being genuine z ∼ 2.2 quasars (QSOs). We extend the 2.2 ≲ z ≲ 3.3 Lyα LF for the first time above LLyα ∼ 1044 erg s−1 and down to densities of ∼10−8 Mpc−3. Our results unveil the Schechter exponential decay of the brightest-end of the Lyα LF in great detail, complementing the power-law component of previous determinations at 43.3 ≲ Log10(LLyα/erg s−1) ≲ 44. We measure Φ* = (3.33 ± 0.19)×10−6, Log(L*) = 44.65 ± 0.65, and α = −1.35 ± 0.84 as an average over the probed redshifts. These values are significantly different from the typical Schechter parameters measured for the Lyα LF of high-z star-forming Lyman-α emitters (LAEs). This implies that z > 2 AGNs/QSOs (likely dominant in our samples) are described by a structurally different LF from that used to describe z > 2 star-forming LAEs, namely LQSOs* ~ 100LLAEs* and ΦQSOs* ~ 10−3 ΦLAEs*, with the transition between the two LFs happening at LLyα ∼ 1043.5 erg s−1. This supports the scenario in which Lyα-emitting AGNs/QSOs are the most abundant class of z ≳ 2 Lyα emitters at LLyα ≳ 1043.3 erg s−1. Finally, we suggest that a significant number of these z ≳ 2 AGNs/QSOs (∼60% of our samples) are currently misclassified as stars based on their broad-band colours, but are identified for the first time as high-z line-emitters by our narrow-band-based selection.
Key words: galaxies: luminosity function / mass function / galaxies: high-redshift / quasars: emission lines / techniques: photometric / methods: observational / surveys
Catalogs are available in electronic form both on the J-PLUS website at https://www.j-plus.es/ancillarydata/dr1_lya_emitting_candidates and at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/643/A149
© ESO 2020
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