{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,19]],"date-time":"2026-03-19T21:28:49Z","timestamp":1773955729731,"version":"3.50.1"},"reference-count":77,"publisher":"EDP Sciences","license":[{"start":{"date-parts":[[2021,12,24]],"date-time":"2021-12-24T00:00:00Z","timestamp":1640304000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.edpsciences.org\/en\/authors\/copyright-and-licensing"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["A&amp;A"],"accepted":{"date-parts":[[2021,9,23]]},"published-print":{"date-parts":[[2022,1]]},"abstract":"<jats:p><jats:italic>Context.<\/jats:italic> We explore the stellar content of the Javalambre Photometric Local Universe Survey (J-PLUS) Data Release 2 and show its potential for identifying low-metallicity stars using the Stellar Parameters Estimation based on Ensemble Methods (SPEEM) pipeline.<\/jats:p>\n<jats:p><jats:italic>Aims.<\/jats:italic> SPEEM is a tool used to provide determinations of atmospheric parameters for stars and separate stellar sources from quasars based on the unique J-PLUS photometric system. The adoption of adequate selection criteria allows for the identification of metal-poor star candidates that are suitable for spectroscopic follow-up investigations.<\/jats:p>\n<jats:p><jats:italic>Methods.<\/jats:italic> SPEEM consists of a series of machine-learning models that use a training sample observed by both J-PLUS and the SEGUE spectroscopic survey. The training sample has temperatures, <jats:italic>T<\/jats:italic><jats:sub>eff<\/jats:sub>, between 4800 K and 9000 K, values of log <jats:italic>g<\/jats:italic> between 1.0 and 4.5, as well as \u22123.1 &lt; [Fe\/H] &lt; +0.5. The performance of the pipeline was tested with a sample of stars observed by the LAMOST survey within the same parameter range.<\/jats:p>\n<jats:p><jats:italic>Results.<\/jats:italic> The average differences between the parameters of a sample of stars observed with SEGUE and J-PLUS, obtained with the SEGUE Stellar Parameter Pipeline and SPEEM, respectively, are \u0394<jats:italic>T<\/jats:italic><jats:sub>eff<\/jats:sub> ~ 41 K, \u0394log <jats:italic>g<\/jats:italic> ~ 0.11 dex, and \u0394[Fe\/H] ~ 0.09 dex. We define a sample of 177 stars that have been identified as new candidates with [Fe\/H] &lt; \u22122.5, with 11 of them having been observed with the ISIS spectrograph at the <jats:italic>William Herschel<\/jats:italic> Telescope. The spectroscopic analysis confirms that 64% of stars have [Fe\/H] &lt; \u22122.5, including one new star with [Fe\/H] &lt; \u22123.0.<\/jats:p>\n<jats:p><jats:italic>Conclusions.<\/jats:italic> Using SPEEM in combination with the J-PLUS filter system has demonstrated their potential in estimating the stellar atmospheric parameters (<jats:italic>T<\/jats:italic><jats:sub>eff<\/jats:sub>, log <jats:italic>g<\/jats:italic>, and [Fe\/H]). The spectroscopic validation of the candidates shows that SPEEM yields a success rate of 64% on the identification of very metal-poor star candidates with [Fe\/H] &lt; \u22122.5.<\/jats:p>","DOI":"10.1051\/0004-6361\/202141717","type":"journal-article","created":{"date-parts":[[2021,10,13]],"date-time":"2021-10-13T09:22:46Z","timestamp":1634116966000},"page":"A35","source":"Crossref","is-referenced-by-count":25,"title":["J-PLUS: Searching for very metal-poor star candidates using the SPEEM pipeline"],"prefix":"10.1051","volume":"657","author":[{"given":"Carlos Andr\u00e9s","family":"Galarza","sequence":"first","affiliation":[]},{"given":"Simone","family":"Daflon","sequence":"additional","affiliation":[]},{"given":"Vinicius M.","family":"Placco","sequence":"additional","affiliation":[]},{"given":"Carlos Allende","family":"Prieto","sequence":"additional","affiliation":[]},{"given":"Marcelo","family":"Borges Fernandes","sequence":"additional","affiliation":[]},{"given":"Haibo","family":"Yuan","sequence":"additional","affiliation":[]},{"given":"Carlos","family":"L\u00f3pez-Sanjuan","sequence":"additional","affiliation":[]},{"given":"Young Sun","family":"Lee","sequence":"additional","affiliation":[]},{"given":"Enrique","family":"Solano","sequence":"additional","affiliation":[]},{"given":"F.","family":"Jim\u00e9nez-Esteban","sequence":"additional","affiliation":[]},{"given":"David","family":"Sobral","sequence":"additional","affiliation":[]},{"given":"Alvaro","family":"Alvarez Candal","sequence":"additional","affiliation":[]},{"given":"Claudio B.","family":"Pereira","sequence":"additional","affiliation":[]},{"given":"Stavros","family":"Akras","sequence":"additional","affiliation":[]},{"given":"Eduardo","family":"Mart\u00edn","sequence":"additional","affiliation":[]},{"given":"Yolanda","family":"Jim\u00e9nez Teja","sequence":"additional","affiliation":[]},{"given":"Javier","family":"Cenarro","sequence":"additional","affiliation":[]},{"given":"David","family":"Crist\u00f3bal-Hornillos","sequence":"additional","affiliation":[]},{"given":"Carlos","family":"Hern\u00e1ndez-Monteagudo","sequence":"additional","affiliation":[]},{"given":"Antonio","family":"Mar\u00edn-Franch","sequence":"additional","affiliation":[]},{"given":"Mariano","family":"Moles","sequence":"additional","affiliation":[]},{"given":"Jes\u00fas","family":"Varela","sequence":"additional","affiliation":[]},{"given":"H\u00e9ctor V\u00e1zquez","family":"Rami\u00f3","sequence":"additional","affiliation":[]},{"given":"Jailson","family":"Alcaniz","sequence":"additional","affiliation":[]},{"given":"Renato","family":"Dupke","sequence":"additional","affiliation":[]},{"given":"Alessandro","family":"Ederoclite","sequence":"additional","affiliation":[]},{"suffix":"Jr.","given":"Laerte","family":"Sodr\u00e9","sequence":"additional","affiliation":[]},{"given":"Raul E.","family":"Angulo","sequence":"additional","affiliation":[]}],"member":"250","published-online":{"date-parts":[[2021,12,24]]},"reference":[{"key":"R1","doi-asserted-by":"crossref","first-page":"804","DOI":"10.1086\/498131","volume":"636","author":"Allende Prieto","year":"2006","journal-title":"ApJ"},{"key":"R2","unstructured":"Almeida-Fernandes F., \nSampedro L., \nHerpich F. 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