Skip to content
DraconiticResearch
Search Sources API
186,123 studies31 sourcesUpdated 53 min ago
Peer-reviewedCC BY 4.0The Astrophysical Journal

The DESI Y1 RR Lyrae Catalog. I. Empirical Modeling of the Cyclic Variation of Spectroscopic Properties and a Chemodynamical Analysis of the Outer Halo

  • G. E. Medina1
  • T. S. Li1
  • S. E. Koposov2,3
  • A. H. Riley4
  • L. Beraldo e Silva5,6
  • M. Valluri7
  • W. Wang8,9
  • A. Byström2
  • O. Y. Gnedin7
  • R. G. Carlberg1
  • N. Kizhuprakkat10
  • B. A. Weaver11
35 more authors
  • J. Aguilar12
  • S. Ahlen13
  • D. Bianchi14,15
  • D. Brooks16
  • T. Claybaugh12
  • A. P. Cooper10
  • A. de la Macorra17
  • A. Dey11
  • P. Doel16
  • A. Font-Ribera18
  • J. E. Forero-Romero19
  • E. Gaztañaga20,21,22
  • S. Gontcho A Gontcho12
  • G. Gutierrez23
  • J. Guy12
  • K. Honscheid24
  • M. Ishak25
  • T. Kisner12
  • M. Landriau12
  • L. Le Guillou26
  • A. Meisner11
  • R. Miquel18,27
  • A. D. Myers28
  • S. Nadathur21
  • C. Poppett12,29
  • F. Prada30
  • I. Pérez-Ràfols31
  • G. Rossi32
  • E. Sanchez33
  • H. Seo34
  • D. Sprayberry11
  • G. Tarlé7
  • R. H. Wechsler35,36
  • R. Zhou12
  • H. Zou37
37 affiliations
  1. 1University of Toronto
  2. 2University of Edinburgh
  3. 3University of Cambridge
  4. 4Durham University
  5. 5University of Arizona
  6. 6Observatório Nacional
  7. 7University of Michigan
  8. 8Shanghai Jiao Tong University
  9. 9Shanghai Key Laboratory for Particle Physics and Cosmology
  10. 10National Tsing Hua University
  11. 11NSF NOIRLab
  12. 12Lawrence Berkeley National Laboratory
  13. 13Boston University
  14. 14Università degli Studi di Milano
  15. 15INAF-Osservatorio Astronomico di Brera
  16. 16University College London
  17. 17Universidad Nacional Autónoma de México
  18. 18Institut de Física d’Altes Energies (IFAE)
  19. 19Universidad de los Andes
  20. 20Institut d’Estudis Espacials de Catalunya (IEEC)
  21. 21University of Portsmouth
  22. 22Institute of Space Sciences
  23. 23Fermi National Accelerator Laboratory
  24. 24The Ohio State University
  25. 25The University of Texas at Dallas
  26. 26Sorbonne Université
  27. 27Institució Catalana de Recerca i Estudis Avançats
  28. 28University of Wyoming
  29. 29University of California
  30. 30Instituto de Astrofísica de Andalucía (CSIC)
  31. 31Universitat Politècnica de Catalunya
  32. 32Sejong University
  33. 33CIEMAT
  34. 34Ohio University
  35. 35Stanford University
  36. 36SLAC National Accelerator Laboratory
  37. 37Chinese Academy of Sciences
Open at sourcePDFDOICite

Abstract

We present the catalog of RR Lyrae stars (RRLs) observed in the first year of operations of the Dark Energy Spectroscopic Instrument (DESI) survey. This catalog contains 6240 RRLs out to ∼120 kpc from the Galactic center and over 12,000 individual epochs with homogeneously derived stellar atmospheric parameters. We introduce a novel methodology to model the cyclical variation of the spectroscopic properties of RRLs from single-epoch measurements. We employ this method to infer the systemic velocities and mean temperatures of fundamental- and first-overtone-mode RRLs in our sample (without distinguishing between individual spectral lines). For fundamental-mode pulsators, we obtain radial velocity curves with amplitudes of ∼30–80 km s ⁻¹ and effective temperature curves with 300–1000 K variations, whereas for first-overtone pulsators these amplitudes are ∼20 km s ⁻¹ and ∼600 K, respectively. We use our sample to study the metallicity distribution of the halo and its dependence on Galactocentric distance ( R GC ). Using a radius-dependent mixture model, we split the data into chemodynamically distinct components and find that our inner halo sample ( R GC ≲ 50 kpc) is predominantly composed of stars with [Fe/H] ∼ −1.5 and largely radial orbits (with an anisotropy parameter β ∼ 0.94), which we associate with the Gaia–Sausage–Enceladus merger. Stars in the halo field exhibit a broader and more metal-poor [Fe/H] distribution with more circular orbits ( β ∼ 0.39). The metallicity gradient of the metal-rich and metal-poor components is found to be 0.005 and 0.010 dex kpc ⁻¹ , respectively. Our catalog highlights DESI’s tantalizing potential for studying the Milky Way and the pulsation properties of RRLs in the era of large spectroscopic surveys.

Related

  1. Nitrogen-Loud Quasars from the Dark Energy Spectroscopic Instrument. I. Sample Selection and Basic Properties
    Shuo Zhai, Wei-Jian Guo, Yong-Jie Chen +4
    arXivPreprintCC BY 4.0Full textGalaxiesarXiv
  2. SPAMMS: 3D spectroscopic modeling of stellar surfaces. II. Implementation of Kurucz and TLUSTY model atmospheres
    D. Galán-Diéguez, M. Abdul-Masih, C. Allende Prieto +3
    arXivPreprintarXiv licenceFull textPlanetary science & exoplanetsSolar & stellar physicsarXiv
  3. SPAMMS: 3D spectroscopic modeling of stellar surfaces
    D. Galán-Diéguez, M. Abdul-Masih, C. Allende Prieto +3
    Astronomy & AstrophysicsPeer-reviewedCC BY 4.0Solar & stellar physicsCrossref
  4. BSN-VIII: Detailed Photometric Modeling of Ten W UMa Contact Binaries and a Revised Empirical Period-Mass Relationship
    Atila Poro, S. Javad Jafarzadeh, Kai Li +15
    arXivPreprintCC BY 4.0Full textSolar & stellar physicsarXiv
  5. Chemodynamical Study and Evidence for Hot Compact Companions to Blue Straggler Stars in Berkeley 31
    Deniz Cennet Çınar, D. Bisht, Ing-Guey Jiang +2
    arXivPreprintarXiv licenceFull textGalaxiesarXiv

Cite

BibTeXRIS
BibTeX
@article{medina2026desi,
  title = {{The DESI Y1 RR Lyrae Catalog. I. Empirical Modeling of the Cyclic Variation of Spectroscopic Properties and a Chemodynamical Analysis of the Outer Halo}},
  author = {G. E. Medina and T. S. Li and S. E. Koposov and A. H. Riley and L. Beraldo e Silva and M. Valluri and W. Wang and A. Byström and O. Y. Gnedin and R. G. Carlberg and N. Kizhuprakkat and B. A. Weaver and J. Aguilar and S. Ahlen and D. Bianchi and D. Brooks and T. Claybaugh and A. P. Cooper and A. de la Macorra and A. Dey and P. Doel and A. Font-Ribera and J. E. Forero-Romero and E. Gaztañaga and S. Gontcho A Gontcho and G. Gutierrez and J. Guy and K. Honscheid and M. Ishak and T. Kisner and M. Landriau and L. Le Guillou and A. Meisner and R. Miquel and A. D. Myers and S. Nadathur and C. Poppett and F. Prada and I. Pérez-Ràfols and G. Rossi and E. Sanchez and H. Seo and D. Sprayberry and G. Tarlé and R. H. Wechsler and R. Zhou and H. Zou},
  journal = {The Astrophysical Journal},
  year = {2026},
  month = oct,
  doi = {10.3847/1538-4357/ae9746},
  url = {https://iopscience.iop.org/article/10.3847/1538-4357/ae9746},
  note = {CC BY 4.0},
}
RIS
TY  - JOUR
TI  - The DESI Y1 RR Lyrae Catalog. I. Empirical Modeling of the Cyclic Variation of Spectroscopic Properties and a Chemodynamical Analysis of the Outer Halo
AU  - G. E. Medina
AU  - T. S. Li
AU  - S. E. Koposov
AU  - A. H. Riley
AU  - L. Beraldo e Silva
AU  - M. Valluri
AU  - W. Wang
AU  - A. Byström
AU  - O. Y. Gnedin
AU  - R. G. Carlberg
AU  - N. Kizhuprakkat
AU  - B. A. Weaver
AU  - J. Aguilar
AU  - S. Ahlen
AU  - D. Bianchi
AU  - D. Brooks
AU  - T. Claybaugh
AU  - A. P. Cooper
AU  - A. de la Macorra
AU  - A. Dey
AU  - P. Doel
AU  - A. Font-Ribera
AU  - J. E. Forero-Romero
AU  - E. Gaztañaga
AU  - S. Gontcho A Gontcho
AU  - G. Gutierrez
AU  - J. Guy
AU  - K. Honscheid
AU  - M. Ishak
AU  - T. Kisner
AU  - M. Landriau
AU  - L. Le Guillou
AU  - A. Meisner
AU  - R. Miquel
AU  - A. D. Myers
AU  - S. Nadathur
AU  - C. Poppett
AU  - F. Prada
AU  - I. Pérez-Ràfols
AU  - G. Rossi
AU  - E. Sanchez
AU  - H. Seo
AU  - D. Sprayberry
AU  - G. Tarlé
AU  - R. H. Wechsler
AU  - R. Zhou
AU  - H. Zou
PY  - 2026
DA  - 2026/10/01
JO  - The Astrophysical Journal
DO  - 10.3847/1538-4357/ae9746
UR  - https://iopscience.iop.org/article/10.3847/1538-4357/ae9746
AB  - We present the catalog of RR Lyrae stars (RRLs) observed in the first year of operations of the Dark Energy Spectroscopic Instrument (DESI) survey. This catalog contains 6240 RRLs out to ∼120 kpc from the Galactic center and over 12,000 individual epochs with homogeneously derived stellar atmospheric parameters. We introduce a novel methodology to model the cyclical variation of the spectroscopic properties of RRLs from single-epoch measurements. We employ this method to infer the systemic velocities and mean temperatures of fundamental- and first-overtone-mode RRLs in our sample (without distinguishing between individual spectral lines). For fundamental-mode pulsators, we obtain radial velocity curves with amplitudes of ∼30–80 km s ⁻¹ and effective temperature curves with 300–1000 K variations, whereas for first-overtone pulsators these amplitudes are ∼20 km s ⁻¹ and ∼600 K, respectively. We use our sample to study the metallicity distribution of the halo and its dependence on Galactocentric distance ( R GC ). Using a radius-dependent mixture model, we split the data into chemodynamically distinct components and find that our inner halo sample ( R GC ≲ 50 kpc) is predominantly composed of stars with [Fe/H] ∼ −1.5 and largely radial orbits (with an anisotropy parameter β ∼ 0.94), which we associate with the Gaia–Sausage–Enceladus merger. Stars in the halo field exhibit a broader and more metal-poor [Fe/H] distribution with more circular orbits ( β ∼ 0.39). The metallicity gradient of the metal-rich and metal-poor components is found to be 0.005 and 0.010 dex kpc ⁻¹ , respectively. Our catalog highlights DESI’s tantalizing potential for studying the Milky Way and the pulsation properties of RRLs in the era of large spectroscopic surveys.
SN  - 0004-637X
SN  - 1538-4357
ER  -