The DECam MAGIC Survey: A Wide-field Photometric Metallicity Study of the Sculptor Dwarf Spheroidal Galaxy
Abstract The metallicity distribution function (MDF) and internal chemical variations of a galaxy are fundamental to understand its formation and assembly history. In this work, we analyze photometric metallicities for 3883 stars over 7 half-light radii ( r h ) in the Sculptor (Scl) dwarf spheroidal (dSph) galaxy, using new narrowband imaging data from the Mapping the Ancient Galaxy in CaHK (MAGIC) survey conducted with the Dark Energy Camera (DECam) at the 4 m Blanco Telescope. This work demonstrates the scientific potential of MAGIC using the Scl dSph galaxy, one of the most well-studied satellites of the Milky Way. Our sample ranges from [Fe/H] ≈ –4.0 to [Fe/H] ≈ –0.6, includes six new extremely metal-poor candidates ([Fe/H] ≤ –3.0), and is almost 3 times larger than the largest spectroscopic metallicity data set in the Scl dSph. Our spatially unbiased sample of metallicities provides a more accurate representation of the MDF, revealing a more metal-rich peak than observed in the most recent spectroscopic sample. It also reveals a break in the metallicity gradient, with a strong change in the slope: from −3.26 ± 0.18 dex deg −1 for stars inside ∼1 r h to −0.55 ± 0.26 dex deg −1 for the outer part of the Scl dSph. Our study demonstrates that combining photometric metallicity analysis with the wide field of view of DECam offers an efficient and unbiased approach for studying the stellar populations of dwarf galaxies in the Local Group.
Authors
- Fabrícia O. Barbosa (ORCID: https://orcid.org/0000-0002-8262-2246)
- Nitya Kallivayalil (ORCID: https://orcid.org/0000-0002-3204-1742)
- G. E. Medina (ORCID: https://orcid.org/0000-0003-0105-9576)
- A. K. Vivas (ORCID: https://orcid.org/0000-0003-4341-6172)
- Guilherme Limberg (ORCID: https://orcid.org/0000-0002-9269-8287)
- W. Cerny (ORCID: https://orcid.org/0000-0003-1697-7062)
- C. E. Martínez-Vázquez (ORCID: https://orcid.org/0000-0002-9144-7726)
- V. M. Placco
- Denija Crnojević (ORCID: https://orcid.org/0000-0002-1763-4128)
- Jeffrey L. Carlin (ORCID: https://orcid.org/0000-0002-3936-9628)
- Alexander H. Riley (ORCID: https://orcid.org/0000-0001-5805-5766)
- Avinash Chaturvedi (ORCID: https://orcid.org/0000-0002-4175-4728)
- S. Rossi
- J. A. Carballo-Bello (ORCID: https://orcid.org/0000-0002-3690-105X)
- A Drlica-Wagner
- Andrew B. Pace (ORCID: https://orcid.org/0000-0002-6021-8760)
- Clécio R. Bom (ORCID: https://orcid.org/0000-0003-4383-2969)
- Burçı̇n Mutlu-Pakdı̇l (ORCID: https://orcid.org/0000-0001-9649-4815)
- P. S. Ferguson (ORCID: https://orcid.org/0000-0001-6957-1627)
- Anirudh Chiti (ORCID: https://orcid.org/0000-0002-7155-679X)
- J. D. Sakowska (ORCID: https://orcid.org/0000-0002-1594-1466)
- M. Navabi (ORCID: https://orcid.org/0000-0001-9438-5228)
- G. S. Stringfellow
- Noelia E. D. Noël (ORCID: https://orcid.org/0000-0002-8282-469X)
- A. Zenteno (ORCID: https://orcid.org/0000-0001-6455-9135)
- Yumi Choi (ORCID: https://orcid.org/0000-0003-1680-1884)
- D. J. Sand
- A. P. Ji
- Kaia R. Atzberger (ORCID: https://orcid.org/0000-0001-9649-8103)
Institutions
- Dartmouth College (US)
- Fermi National Accelerator Laboratory (US)
- University of Toronto (CA)
- University of Tarapacá (CL)
- University of Colorado Boulder (US)
- Durham University (GB)
- University of Washington (US)
- Chestnut Hill College (US)
- University of South Florida (US)
- University of Colorado System (US)
- University of Surrey (GB)
- Yale University (US)
- University of Chicago (US)
- National Solar Observatory (US)
- Kavli Institute for Particle Astrophysics and Cosmology (US)
- Astron Wireless Technologies (United States) (US)
- Gemini North Observatory (US)
- McCormick (United States) (US)
- Indiana Cancer Consortium (US)
- Canadian Institute for Theoretical Astrophysics (CA)
- Laboratory for Atmospheric and Space Physics (US)
- Centro Brasileiro de Pesquisas Físicas (BR)
- 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)
- Dartmouth Hospital (GB)
- City University of Seattle (US)
- University of Virginia (US)
- Seattle University (US)
- University of South Florida St. Petersburg (US)
- Netherlands Institute for Radio Astronomy (NL)
- University of Tampa (US)
- Stanford University (US)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-10-24
- DOI
- https://doi.org/10.3847/1538-4357/ae0039
- Citations
- 3
- Primary Topic
- Stellar, planetary, and galactic studies
- Type
- article
- Field-Weighted Citation Impact
- 3.46
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- Yale University
- University of Chicago
- Fundação de Amparo à Pesquisa do Estado de São Paulo
- Kavli Institute for Cosmological Physics, University of Chicago
- Laboratory Directed Research and Development
- Fermilab