{"id":"https://openalex.org/W4416396237","doi":"https://doi.org/10.33232/001c.147696","title":"A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II","display_name":"A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II","publication_year":2025,"publication_date":"2025-11-19","ids":{"openalex":"https://openalex.org/W4416396237","doi":"https://doi.org/10.33232/001c.147696"},"language":"en","primary_location":{"id":"doi:10.33232/001c.147696","doi":"https://doi.org/10.33232/001c.147696","is_oa":true,"landing_page_url":"https://doi.org/10.33232/001c.147696","pdf_url":null,"source":{"id":"https://openalex.org/S4210224606","display_name":"The Open Journal of Astrophysics","issn_l":"2565-6120","issn":["2565-6120"],"is_oa":true,"is_in_doaj":true,"is_core":true,"listed_in":["cwts-core","doaj","jufo-1","norway-1"],"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"The Open Journal of Astrophysics","raw_type":"journal-article"},"volume":null,"type":"article","indexed_in":["arxiv","crossref","datacite","doaj"],"open_access":{"is_oa":true,"oa_status":"diamond","oa_url":"https://doi.org/10.33232/001c.147696","any_repository_has_fulltext":true},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5035275696","display_name":"Alice Luna","orcid":"https://orcid.org/0009-0009-9570-0715","observed_orcids":["https://orcid.org/0009-0009-9570-0715"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Alice M. Luna","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]},{"author_position":"middle","author":{"id":"https://openalex.org/A5032289846","display_name":"Alexander P. Ji","orcid":"https://orcid.org/0000-0002-4863-8842","observed_orcids":["https://orcid.org/0000-0002-4863-8842"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Alexander P. Ji","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]},{"author_position":"middle","author":{"id":"https://openalex.org/A5064678524","display_name":"Anirudh Chiti","orcid":"https://orcid.org/0000-0002-7155-679X","observed_orcids":["https://orcid.org/0000-0002-7155-679X"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Anirudh Chiti","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]},{"author_position":"middle","author":{"id":"https://openalex.org/A5042925803","display_name":"Joshua D. Simon","orcid":"https://orcid.org/0000-0002-4733-4994","observed_orcids":["https://orcid.org/0000-0002-4733-4994"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Joshua D. Simon","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]},{"author_position":"middle","author":{"id":"https://openalex.org/A5084948126","display_name":"Daniel D. Kelson","orcid":"https://orcid.org/0000-0003-4727-4327","observed_orcids":["https://orcid.org/0000-0003-4727-4327"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Daniel D. Kelson","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]},{"author_position":"middle","author":{"id":"https://openalex.org/A5118571851","display_name":"Minsung Go","orcid":"https://orcid.org/0009-0008-7277-3818","observed_orcids":["https://orcid.org/0009-0008-7277-3818"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Minsung Go","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]},{"author_position":"middle","author":{"id":"https://openalex.org/A5011594887","display_name":"Guilherme Limberg","orcid":"https://orcid.org/0000-0002-9269-8287","observed_orcids":["https://orcid.org/0000-0002-9269-8287"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Guilherme Limberg","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]},{"author_position":"middle","author":{"id":"https://openalex.org/A5017684904","display_name":"Ting S. Li","orcid":"https://orcid.org/0000-0002-9110-6163","observed_orcids":["https://orcid.org/0000-0002-9110-6163"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Ting S. Li","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]},{"author_position":"last","author":{"id":"https://openalex.org/A5049021876","display_name":"Anna Frebel","orcid":"https://orcid.org/0000-0002-2139-7145","observed_orcids":["https://orcid.org/0000-0002-2139-7145"]},"institutions":[],"countries":[],"is_corresponding":false,"raw_author_name":"Anna Frebel","raw_affiliation_strings":[],"raw_orcid":null,"affiliations":[]}],"institutions":[],"countries_distinct_count":0,"institutions_distinct_count":0,"corresponding_author_ids":[],"corresponding_institution_ids":[],"apc_list":null,"apc_paid":null,"fwci":1.9357,"has_fulltext":false,"cited_by_count":4,"citation_normalized_percentile":{"value":0.86688009,"is_in_top_1_percent":false,"is_in_top_10_percent":false},"cited_by_percentile_year":{"min":98,"max":99},"biblio":{"volume":"8","issue":null,"first_page":null,"last_page":null},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10026","display_name":"Galaxies: Formation, Evolution, Phenomena","score":0.5038999915122986,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T10026","display_name":"Galaxies: Formation, Evolution, Phenomena","score":0.5038999915122986,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10039","display_name":"Stellar, planetary, and galactic studies","score":0.48660001158714294,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10477","display_name":"Astrophysics and Star Formation Studies","score":0.002199999988079071,"subfield":{"id":"https://openalex.org/subfields/3103","display_name":"Astronomy and Astrophysics"},"field":{"id":"https://openalex.org/fields/31","display_name":"Physics and Astronomy"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/reticulum-ii","display_name":"Reticulum II","score":0.9580000042915344},{"id":"https://openalex.org/keywords/ultra-faint-dwarf-galaxies","display_name":"ultra-faint dwarf galaxies","score":0.996999979019165},{"id":"https://openalex.org/keywords/metallicity-distribution-function","display_name":"metallicity distribution function","score":0.9829999804496765},{"id":"https://openalex.org/keywords/cosmic-reionization","display_name":"cosmic reionization","score":0.7419999837875366},{"id":"https://openalex.org/keywords/main-sequence-turn-off-stars","display_name":"main-sequence turnoff stars","score":0.9269999861717224},{"id":"https://openalex.org/keywords/red-giant-branch-stars","display_name":"red giant branch stars","score":0.7829999923706055},{"id":"https://openalex.org/keywords/stellar-metallicity","display_name":"stellar metallicity","score":0.5379999876022339}],"concepts":[{"id":"https://openalex.org/C121332964","wikidata":"https://www.wikidata.org/wiki/Q413","display_name":"Physics","level":0,"score":0.8906999826431274},{"id":"https://openalex.org/C44870925","wikidata":"https://www.wikidata.org/wiki/Q37547","display_name":"Astrophysics","level":1,"score":0.8098999857902527},{"id":"https://openalex.org/C99465377","wikidata":"https://www.wikidata.org/wiki/Q217030","display_name":"Metallicity","level":3,"score":0.7200000286102295},{"id":"https://openalex.org/C37119246","wikidata":"https://www.wikidata.org/wiki/Q190438","display_name":"Dwarf galaxy","level":3,"score":0.6747999787330627},{"id":"https://openalex.org/C150846664","wikidata":"https://www.wikidata.org/wiki/Q7602306","display_name":"Stars","level":2,"score":0.6498000025749207},{"id":"https://openalex.org/C98444146","wikidata":"https://www.wikidata.org/wiki/Q318","display_name":"Galaxy","level":2,"score":0.5551999807357788},{"id":"https://openalex.org/C125857072","wikidata":"https://www.wikidata.org/wiki/Q16744","display_name":"Star formation","level":3,"score":0.4374000132083893},{"id":"https://openalex.org/C1276947","wikidata":"https://www.wikidata.org/wiki/Q333","display_name":"Astronomy","level":1,"score":0.4223000109195709},{"id":"https://openalex.org/C189159749","wikidata":"https://www.wikidata.org/wiki/Q1194026","display_name":"Initial mass function","level":4,"score":0.3806999921798706},{"id":"https://openalex.org/C80518518","wikidata":"https://www.wikidata.org/wiki/Q863936","display_name":"K-type main-sequence star","level":4,"score":0.3668999969959259},{"id":"https://openalex.org/C127592171","wikidata":"https://www.wikidata.org/wiki/Q3937","display_name":"Supernova","level":2,"score":0.34310001134872437},{"id":"https://openalex.org/C438757","wikidata":"https://www.wikidata.org/wiki/Q654754","display_name":"Dwarf spheroidal galaxy","level":5,"score":0.32710000872612},{"id":"https://openalex.org/C32891209","wikidata":"https://www.wikidata.org/wiki/Q483666","display_name":"Spectroscopy","level":2,"score":0.3260999917984009},{"id":"https://openalex.org/C17959413","wikidata":"https://www.wikidata.org/wiki/Q899219","display_name":"Luminosity function","level":4,"score":0.3149000108242035},{"id":"https://openalex.org/C56956389","wikidata":"https://www.wikidata.org/wiki/Q3450","display_name":"Main sequence","level":3,"score":0.30320000648498535},{"id":"https://openalex.org/C188525179","wikidata":"https://www.wikidata.org/wiki/Q190397","display_name":"Irregular galaxy","level":5,"score":0.2892000079154968},{"id":"https://openalex.org/C63585750","wikidata":"https://www.wikidata.org/wiki/Q2488","display_name":"Spiral galaxy","level":3,"score":0.2793999910354614},{"id":"https://openalex.org/C164546044","wikidata":"https://www.wikidata.org/wiki/Q285400","display_name":"Flare star","level":5,"score":0.2766999900341034},{"id":"https://openalex.org/C85837739","wikidata":"https://www.wikidata.org/wiki/Q5875","display_name":"Giant star","level":3,"score":0.271699994802475},{"id":"https://openalex.org/C9652623","wikidata":"https://www.wikidata.org/wiki/Q190109","display_name":"Field (mathematics)","level":2,"score":0.27079999446868896}],"mesh":[],"locations_count":4,"locations":[{"id":"doi:10.33232/001c.147696","doi":"https://doi.org/10.33232/001c.147696","is_oa":true,"landing_page_url":"https://doi.org/10.33232/001c.147696","pdf_url":null,"source":{"id":"https://openalex.org/S4210224606","display_name":"The Open Journal of Astrophysics","issn_l":"2565-6120","issn":["2565-6120"],"is_oa":true,"is_in_doaj":true,"is_core":true,"listed_in":["cwts-core","doaj","jufo-1","norway-1"],"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"The Open Journal of Astrophysics","raw_type":"journal-article"},{"id":"pmh:oai:arXiv.org:2506.16462","doi":null,"is_oa":true,"landing_page_url":"http://arxiv.org/abs/2506.16462","pdf_url":"https://arxiv.org/pdf/2506.16462","source":{"id":"https://openalex.org/S4306400194","display_name":"arXiv (Cornell University)","issn_l":"2331-8422","issn":["2331-8422"],"is_oa":true,"is_in_doaj":false,"is_core":false,"listed_in":[],"host_organization":"https://openalex.org/I205783295","host_organization_name":"Cornell University","host_organization_lineage":["https://openalex.org/I205783295"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":null,"raw_type":"text"},{"id":"pmh:oai:doaj.org/article:1dab49723f2842c5bd5570f265e2c232","doi":null,"is_oa":true,"landing_page_url":"https://doaj.org/article/1dab49723f2842c5bd5570f265e2c232","pdf_url":null,"source":{"id":"https://openalex.org/S4306401280","display_name":"DOAJ (DOAJ: Directory of Open Access Journals)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"listed_in":[],"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by-sa","license_id":"https://openalex.org/licenses/cc-by-sa","version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"The Open Journal of Astrophysics, Vol 8 (2025)","raw_type":"article"},{"id":"doi:10.48550/arxiv.2506.16462","doi":"https://doi.org/10.48550/arxiv.2506.16462","is_oa":true,"landing_page_url":"https://doi.org/10.48550/arxiv.2506.16462","pdf_url":null,"source":{"id":"https://openalex.org/S4306400194","display_name":"arXiv (Cornell University)","issn_l":"2331-8422","issn":["2331-8422"],"is_oa":true,"is_in_doaj":false,"is_core":false,"listed_in":[],"host_organization":"https://openalex.org/I205783295","host_organization_name":"Cornell University","host_organization_lineage":["https://openalex.org/I205783295"],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":null,"is_accepted":false,"is_published":null,"raw_source_name":null,"raw_type":"Preprint"}],"best_oa_location":{"id":"doi:10.33232/001c.147696","doi":"https://doi.org/10.33232/001c.147696","is_oa":true,"landing_page_url":"https://doi.org/10.33232/001c.147696","pdf_url":null,"source":{"id":"https://openalex.org/S4210224606","display_name":"The Open Journal of Astrophysics","issn_l":"2565-6120","issn":["2565-6120"],"is_oa":true,"is_in_doaj":true,"is_core":true,"listed_in":["cwts-core","doaj","jufo-1","norway-1"],"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"The Open Journal of Astrophysics","raw_type":"journal-article"},"sustainable_development_goals":[],"sustainable_development_goals_aurora":[],"study_designs":[],"awards":[],"funders":[],"has_content":{"pdf":false,"grobid_xml":false},"content_urls":null,"referenced_works_count":0,"referenced_works":[],"related_works":[],"abstract_inverted_index":{"Star":[0],"formation":[1,190],"in":[2,32,63,75,99,125,148,159],"ultra-faint":[3,33],"dwarf":[4,34],"galaxies":[5,35,200],"(UFDs,":[6],"M":[7,12,81,85],"*":[8,82],"<":[9],"10":[10],"5":[11],"\u2299":[13,86],")":[14],"is":[15,111,133],"suppressed":[16],"by":[17,94,174],"reionization,":[18],"but":[19],"may":[20],"not":[21],"be":[22,172],"completely":[23],"quenched.":[24],"The":[25,128],"metallicity":[26,104,169],"distribution":[27,105],"function":[28,106],"(MDF)":[29],"of":[30,40,45,72,91,107,120,130,145,156],"stars":[31,62,74,124,147,158,204],"could":[36],"show":[37],"these":[38],"signatures":[39],"reionization.":[41,206],"However,":[42],"past":[43],"studies":[44],"UFD":[46,77],"MDFs":[47],"have":[48],"been":[49],"limited,":[50],"because":[51,113],"there":[52],"are":[53],"only":[54],"a":[55,135,167,180],"few":[56],"dozen":[57],"red":[58],"giant":[59],"branch":[60],"(RGB)":[61],"such":[64,198],"low-mass":[65,199],"galaxies.":[66],"We":[67],"present":[68],"low-resolution":[69],"Magellan/IMACS":[70],"spectroscopy":[71],"167":[73],"the":[76,89,100,116,146,149,157,160,186],"Reticulum":[78,131,193],"II":[79,132,194],"(":[80],"\u2248":[83],"3000":[84],"),":[87],"increasing":[88],"number":[90],"stellar":[92],"metallicities":[93,119],"6.5":[95],"times":[96],"and":[97,153,195],"resulting":[98],"most":[101],"populated":[102],"spectroscopic":[103,118],"any":[108,126],"UFD.":[109,127],"This":[110,184],"possible":[112],"we":[114],"determined":[115],"first":[117],"main":[121],"sequence":[122],"turn-off":[123],"MDF":[129],"clearly":[134,201],"bimodal":[136],"distribution,":[137],"displaying":[138],"two":[139],"peaks":[140],"with":[141],"about":[142],"80":[143],"%":[144,155],"metal-poor":[150],"peak":[151,163],"at":[152,164],"20":[154],"more":[161],"metal-rich":[162],".":[165],"Such":[166],"large":[168],"gap":[170],"can":[171,202],"explained":[173],"Type":[175],"Ia":[176],"supernova":[177],"enrichment":[178],"during":[179],"long":[181],"quiescent":[182],"period.":[183],"supports":[185],"currently-favored":[187],"two-burst":[188],"star":[189],"history":[191],"for":[192],"shows":[196],"that":[197],"form":[203],"after":[205]},"counts_by_year":[{"year":2026,"cited_by_count":4}],"updated_date":"2026-09-29T14:09:16.559479","created_date":"2025-11-19T00:00:00"}