J-PLUS: Measuring H α emission line fluxes in the nearby universe
In this paper we aim to validate a methodology designed to obtain Hα emission line fluxes from J-PLUS photometric data. J-PLUS is a multi narrow-band filter survey carried out with the 2 deg2 field of view T80Cam camera, mounted on the JAST/T80 telescope in the OAJ, Teruel, Spain. The information of the twelve J-PLUS bands, including the J0660 narrow-band filter located at rest-frame Hα, is used over the first 42 deg2 observed to retrieve de-reddened and [NII] decontaminated Hα emission line fluxes of 46 star-forming regions with previous SDSS and/or CALIFA spectroscopic information. The agreement between the J-PLUS Hα fluxes and those obtained with spectroscopic data is remarkable, finding a median comparison ratio with a scatter of R = FJ-PLUS Hα=Fspec Hα = 1:05 ± 0:25. This demonstrates that it is possible to retrieve reliable Hα emission line fluxes from J-PLUS photometric data. With an expected area of thousands of square degrees upon completion, the J-PLUS dataset will allow the study of several star formation science cases in the nearby universe, as the spatially resolved star formation rate of nearby galaxies at z ≤ 0:015, and how it is influenced by the environment, morphology, stellar mass, and nuclear activity. As an illustrative example, the close pair of interacting galaxies NGC 3994 and NGC 3995 is analysed, finding an enhancement of the star formation rate not only in the centre, but also in outer parts of the disk of NGC 3994. ; Funding for the J-PLUS Project has been provided by the Governments of Spain and Aragon through the Fondo de Inversiones de Teruel, the Aragon Government through the Reseach Groups E96 and E103, the Spanish Ministry of Economy and Competitiveness (MINECO; under grants AYA2015-66211-C2-1-P, AYA2015-66211-C2-2, AYA2012-30789 and ICTS-2009-14), and European FEDER funding (FCDD10-4E-867, FCDD13-4E-2685). R.L.G acknowledges support from >Obra social de la fundacion bancaria Ibercaja>. K.V. acknowledges the Juan de la Cierva Incorporacion fellowship, IJCI-2014-21960, of the Spanish government. R.A.D acknowledges support from CNPq through BP grant 312307/2015-2, CSIC through grant COOPB20263, FINEP grants REF. 1217/13-01.13.0279.00 and REF 0859/10-01.10.0663.00 for partial hardware support for the J-PLUS project through the National Observatory of Brazil. L.G. was supported in part by the US National Science Foundation under Grant AST-1311862. R.M.G.D was supported by AYA2016-77846-P, AYA2014-57490-P, and Junta de Andalucia FQ1580. J.A.H.J. and S.A. thank the Brazilian institution CNPq for financial support through post-doctoral fellowship (project 150237/2017-0 and 300336/2016-0, respectively).R.L.O. was partially supported by the Brazilian agency CNPq (Universal Grants 459553/2014-3, PQ 302037/2015-2, and PDE 200289/2017-9). ; Peer Reviewed
