The DECam MAGIC Survey: Spectroscopic Follow-up of the Most Metal-poor Stars in the Distant Milky Way Halo<sup>*</sup>

Abstract In this work, we present high-resolution spectroscopic observations for six metal-poor stars with [Fe/H] &lt; –3 (including one with [Fe/H] &lt; –4), selected using narrowband Ca ii HK photometry from the DECam MAGIC Survey. The spectroscopic data confirm the accuracy of the photometric metallicities and allow for the determination of chemical abundances for 16 elements, from carbon to barium. The program stars have chemical abundances consistent with the [Fe/H] &lt; –3 range. A kinematic/dynamical analysis suggests that all program stars belong to the distant Milky Way halo population (heliocentric distances 35 &lt; d helio /kpc ≲ 55), including three with high-energy orbits that might have been associated with the Magellanic system and one, J0026−5445, having parameters consistent with being a member of the Sagittarius stream. The remaining two stars show kinematics consistent with the Gaia-Sausage/Enceladus dwarf galaxy merger. J0433−5548, with [Fe/H] = –4.12, is a carbon-enhanced ultra metal-poor star, with [C/Fe] = +1.73. This star is believed to be a bona fide second-generation star, and its chemical abundance pattern was compared with yields from metal-free supernova models. Results suggest that J0433−5548 could have been formed from a gas cloud enriched by a single supernova explosion from an ∼11 M ⊙ star in the early Universe. The successful identification of such objects demonstrates the reliability of photometric metallicity estimates, which can be used for target selection and statistical studies of faint targets in the Milky Way and its satellite population. These discoveries illustrate the power of measuring chemical abundances of metal-poor Milky Way halo stars to learn more about early galaxy formation and evolution.

Authors

Institutions

Publication Details

Journal
The Astrophysical Journal
Published
2025-09-18
DOI
https://doi.org/10.3847/1538-4357/adf846
Citations
7
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
8.08

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

The DECam MAGIC Survey: Spectroscopic Follow-up of the Most Metal-poor Stars in the Distant Milky Way Halo*

Fabrícia O. Barbosa, G. E. Medina, A. K. Vivas, Guilherme Limberg et al.
7 citations
The Astrophysical Journal
Stellar, planetary, and galactic studies
8.08
article

The DECam MAGIC Survey: Spectroscopic Follow-up of the Most Metal-poor Stars in the Distant Milky Way Halo*

Fabrícia O. Barbosa, G. E. Medina, A. K. Vivas, Guilherme Limberg, Silvia Rossi, Chin Yi Tan, W. Cerny, C. E. Martínez-Vázquez, Denija Crnojević, Guy S. Stringfellow, Alexander P. Ji, Alexander H. Riley, Pol Massana, J. A. Carballo-Bello, Deepthi S. Prabhu, Vinicius M. Placco, Andrew B. Pace, Burçı̇n Mutlu-Pakdı̇l, David J. Sand, Anirudh Chiti, J. D. Sakowska, A. Drlica-Wagner, Noelia E. D. Noël, Yumi Choi
article en
7 citations

Abstract

Abstract In this work, we present high-resolution spectroscopic observations for six metal-poor stars with [Fe/H] &lt; –3 (including one with [Fe/H] &lt; –4), selected using narrowband Ca ii HK photometry from the DECam MAGIC Survey. The spectroscopic data confirm the accuracy of the photometric metallicities and allow for the determination of chemical abundances for 16 elements, from carbon to barium. The program stars have chemical abundances consistent with the [Fe/H] &lt; –3 range. A kinematic/dynamical analysis suggests that all program stars belong to the distant Milky Way halo population (heliocentric distances 35 &lt; d helio /kpc ≲ 55), including three with high-energy orbits that might have been associated with the Magellanic system and one, J0026−5445, having parameters consistent with being a member of the Sagittarius stream. The remaining two stars show kinematics consistent with the Gaia-Sausage/Enceladus dwarf galaxy merger. J0433−5548, with [Fe/H] = –4.12, is a carbon-enhanced ultra metal-poor star, with [C/Fe] = +1.73. This star is believed to be a bona fide second-generation star, and its chemical abundance pattern was compared with yields from metal-free supernova models. Results suggest that J0433−5548 could have been formed from a gas cloud enriched by a single supernova explosion from an ∼11 M ⊙ star in the early Universe. The successful identification of such objects demonstrates the reliability of photometric metallicity estimates, which can be used for target selection and statistical studies of faint targets in the Milky Way and its satellite population. These discoveries illustrate the power of measuring chemical abundances of metal-poor Milky Way halo stars to learn more about early galaxy formation and evolution.

The Astrophysical JournalVol. 991(1)
Dartmouth College (US), Fermi National Accelerator Laboratory (US), Universidade de São Paulo (BR), University of Toronto (CA), University of Tarapacá (CL), University of Colorado Boulder (US), Durham University (GB), Kitt Peak National Observatory (US), University of Surrey (GB), Yale University (US), University of Hawaii at Hilo (US), University of Chicago (US), McCormick (United States) (US), Simons Foundation (US), Laboratory for Atmospheric and Space Physics (US), Gemini South Observatory (CL), Community Science and Data Center (US), Cerro Tololo Inter-American Observatory (CL), NSF NOIRLab (US), Instituto de Geofísica y Astronomía (CU), Instituto de Astrofísica de Andalucía (ES), University of Virginia (US), University of La Serena (CL), University of Tampa (US)
National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Ohio State University, University of Chicago, University College London, Deutsche Forschungsgemeinschaft, Fundação de Amparo à Pesquisa do Estado de São Paulo, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Ministério da Ciência, Tecnologia e Inovação, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Financiadora de Estudos e Projetos, Institut de Física d'Altes Energies, University of Illinois at Urbana-Champaign, Kavli Institute for Cosmological Physics, University of Chicago, Science and Technology Facilities Council, Laboratory Directed Research and Development, Integrated Electronics Engineering Center, Binghamton University, Argonne National Laboratory, Fermilab, Lawrence Berkeley National Laboratory
Openalex Percentile: Top 3%
Stellar, planetary, and galactic studies
8.08
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.