The Astrophysical Journal (Jan 2025)
GD-1 Stellar Stream and Cocoon in the DESI Early Data Release
- M. Valluri,
- P. Fagrelius,
- S. E. Koposov,
- T. S. Li,
- Oleg Y. Gnedin,
- E. F. Bell,
- R. G. Carlberg,
- A. P. Cooper,
- J. Aguilar,
- S. Ahlen,
- C. Allende Prieto,
- V. Belokurov,
- L. Beraldo e Silva,
- D. Brooks,
- A. Byström,
- T. Claybaugh,
- K. Dawson,
- A. Dey,
- P. Doel,
- J. E. Forero-Romero,
- E. Gaztañaga,
- S. Gontcho A Gontcho,
- J. Han,
- K. Honscheid,
- T. Kisner,
- A. Kremin,
- A. Lambert,
- M. Landriau,
- L. Le Guillou,
- M. E. Levi,
- A. de la Macorra,
- M. Manera,
- P. Martini,
- G. E. Medina,
- A. Meisner,
- R. Miquel,
- J. Moustakas,
- A. D. Myers,
- J. Najita,
- C. Poppett,
- F. Prada,
- M. Rezaie,
- G. Rossi,
- A. H. Riley,
- E. Sanchez,
- D. Schlegel,
- M. Schubnell,
- D. Sprayberry,
- G. Tarlé,
- G. Thomas,
- B. A. Weaver,
- R. H. Wechsler,
- R. Zhou,
- H. Zou
Affiliations
- M. Valluri
- ORCiD
- Department of Astronomy, University of Michigan , Ann Arbor, MI 48109, USA ; [email protected]
- P. Fagrelius
- NSF NOIRLab , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- S. E. Koposov
- ORCiD
- Institute for Astronomy, University of Edinburgh , Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK; Institute of Astronomy, University of Cambridge , Madingley Road, Cambridge CB3 0HA, UK
- T. S. Li
- ORCiD
- Department of Astronomy & Astrophysics, University of Toronto , Toronto, ON M5S 3H4, Canada
- Oleg Y. Gnedin
- ORCiD
- Department of Astronomy, University of Michigan , Ann Arbor, MI 48109, USA ; [email protected]
- E. F. Bell
- ORCiD
- Department of Astronomy, University of Michigan , Ann Arbor, MI 48109, USA ; [email protected]
- R. G. Carlberg
- ORCiD
- Department of Astronomy & Astrophysics, University of Toronto , Toronto, ON M5S 3H4, Canada
- A. P. Cooper
- ORCiD
- Institute of Astronomy and Department of Physics, National Tsing Hua University , 101 Kuang-Fu Road Sec. 2, Hsinchu 30013, Taiwan
- J. Aguilar
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- S. Ahlen
- ORCiD
- Physics Dept., Boston University , 590 Commonwealth Avenue, Boston, MA 02215, USA
- C. Allende Prieto
- ORCiD
- Departamento de Astrofísica, Universidad de La Laguna (ULL) , E-38206, La Laguna, Tenerife, Spain; Instituto de Astrofísica de Canarias , C/ Vía Láctea, s/n, E-38205 La Laguna, Tenerife, Spain
- V. Belokurov
- ORCiD
- Institute of Astronomy , Madingley Road, Cambridge CB3 0HA, UK
- L. Beraldo e Silva
- ORCiD
- Steward Observatory, University of Arizona , 933 N, Cherry Avenue, Tucson, AZ 85721, USA
- D. Brooks
- ORCiD
- Department of Physics & Astronomy, University College London , Gower Street, London, WC1E 6BT, UK
- A. Byström
- ORCiD
- Institute for Astronomy, University of Edinburgh , Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
- T. Claybaugh
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- K. Dawson
- ORCiD
- Department of Physics and Astronomy, The University of Utah , 115 South 1400 East, Salt Lake City, UT 84112, USA
- A. Dey
- ORCiD
- NSF NOIRLab , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- P. Doel
- Department of Physics & Astronomy, University College London , Gower Street, London, WC1E 6BT, UK
- J. E. Forero-Romero
- ORCiD
- Departamento de Física, Universidad de los Andes , Cra. 1 No. 18A-10, Edificio Ip, CP 111711, Bogotá, Colombia
- E. Gaztañaga
- ORCiD
- Institut d’Estudis Espacials de Catalunya (IEEC) , 08034 Barcelona, Spain; Institute of Cosmology and Gravitation, University of Portsmouth , Dennis Sciama Building, Portsmouth, PO1 3FX, UK; Institute of Space Sciences , ICE-CSIC, Campus UAB, Carrer de Can Magrans s/n, 08913 Bellaterra, Barcelona, Spain
- S. Gontcho A Gontcho
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- J. Han
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- K. Honscheid
- Center for Cosmology and AstroParticle Physics, The Ohio State University , 191 West Woodruff Avenue, Columbus, OH 43210, USA; Department of Physics, The Ohio State University , 191 West Woodruff Avenue, Columbus, OH 43210, USA; The Ohio State University , Columbus, 43210 OH, USA
- T. Kisner
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- A. Kremin
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- A. Lambert
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- M. Landriau
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- L. Le Guillou
- ORCiD
- Sorbonne Université , CNRS/IN2P3, Laboratoire de Physique Nucléaire et de Hautes Energies (LPNHE), FR-75005 Paris, France
- M. E. Levi
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- A. de la Macorra
- ORCiD
- Instituto de Física, Universidad Nacional Autónoma de México , Cd. de México C.P. 04510, México
- M. Manera
- ORCiD
- Departament de Física, Serra Húnter, Universitat Autònoma de Barcelona , 08193 Bellaterra (Barcelona), Spain; Institut de Física d’Altes Energies (IFAE) , The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra Barcelona, Spain
- P. Martini
- ORCiD
- Center for Cosmology and AstroParticle Physics, The Ohio State University , 191 West Woodruff Avenue, Columbus, OH 43210, USA; The Ohio State University , Columbus, 43210 OH, USA; Department of Astronomy, The Ohio State University , 4055 McPherson Laboratory, 140 W 18th Avenue, Columbus, OH 43210, USA
- G. E. Medina
- ORCiD
- Department of Astronomy & Astrophysics, University of Toronto , Toronto, ON M5S 3H4, Canada
- A. Meisner
- ORCiD
- NSF NOIRLab , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- R. Miquel
- Institut de Física d’Altes Energies (IFAE) , The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats , Passeig de Lluís Companys, 23, 08010 Barcelona, Spain
- J. Moustakas
- ORCiD
- Department of Physics and Astronomy, Siena College , 515 Loudon Road, Loudonville, NY 12211, USA
- A. D. Myers
- Department of Physics & Astronomy, University of Wyoming , 1000 E. University, Dept. 3905, Laramie, WY 82071, USA
- J. Najita
- ORCiD
- NSF NOIRLab , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- C. Poppett
- Space Sciences Laboratory, University of California , Berkeley, 7 Gauss Way, Berkeley, CA 94720, USA; University of California , Berkeley, 110 Sproul Hall #5800 Berkeley, CA 94720, USA
- F. Prada
- ORCiD
- Instituto de Astrofísica de Andalucía (CSIC) , Glorieta de la Astronomía, s/n, E-18008 Granada, Spain
- M. Rezaie
- ORCiD
- Department of Physics, Kansas State University , 116 Cardwell Hall, Manhattan, KS 66506, USA
- G. Rossi
- Department of Physics and Astronomy, Sejong University , Seoul, 143-747, Republic of Korea
- A. H. Riley
- ORCiD
- Institute for Computational Cosmology, Department of Physics, Durham University , South Road, Durham DH1 3LE, UK
- E. Sanchez
- ORCiD
- CIEMAT , Avenida Complutense 40, E-28040 Madrid, Spain
- D. Schlegel
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- M. Schubnell
- Department of Physics, University of Michigan , Ann Arbor, MI 48109, USA; University of Michigan , Ann Arbor, MI 48109, USA
- D. Sprayberry
- ORCiD
- NSF NOIRLab , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- G. Tarlé
- ORCiD
- University of Michigan , Ann Arbor, MI 48109, USA
- G. Thomas
- ORCiD
- Instituto de Astrofísica de Canarias , C/ Vía Láctea, s/n, E-38205 La Laguna, Tenerife, SpainDepartamento de Astrofísica, Universidad de La Laguna (ULL), E-38206, La Laguna, Tenerife, Spain
- B. A. Weaver
- NSF NOIRLab , 950 N. Cherry Avenue, Tucson, AZ 85719, USA
- R. H. Wechsler
- ORCiD
- Kavli Institute for Particle Astrophysics and Cosmology, Stanford University , Menlo Park, CA 94305, USA; Physics Department, Stanford University , Stanford, CA 93405, USA; SLAC National Accelerator Laboratory , Menlo Park, CA 94305, USA
- R. Zhou
- ORCiD
- Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA 94720, USA
- H. Zou
- ORCiD
- National Astronomical Observatories , Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing, 100012, People's Republic of China
- DOI
- https://doi.org/10.3847/1538-4357/ada690
- Journal volume & issue
-
Vol. 980,
no. 1
p. 71
Abstract
We present ∼115 new spectroscopically identified members of the GD-1 tidal stream observed with the 5000-fiber Dark Energy Spectroscopic Instrument (DESI). We confirm the existence of a “cocoon,” which is a broad (FWHM ∼ 2 $\mathop{.}\limits^{\unicode{x000b0}}$ 932 ∼ 460 pc) and kinematically hot (velocity dispersion, σ ∼ 5–8 km s ^−1 ) component that surrounds a narrower (FWHM ∼ 0 $\mathop{.}\limits^{\unicode{x000b0}}$ 353 ∼ 55 pc) and colder [( σ = 3.09 ± 0.76 km s ^−1 )] thin stream component (based on a median per star velocity precision of 2.7 km s ^−1 ). The cocoon extends over at least a 30 ^∘ segment of the stream observed by DESI. The thin and cocoon components have similar mean values of [Fe/H]: −2.54 ± 0.04 dex and −2.47 ± 0.06 dex, suggestive of a common origin. The data are consistent with the following scenarios for the origin of the cocoon. The progenitor of the GD-1 stream was an accreted globular cluster (GC) and: (a) the cocoon was produced by pre-accretion tidal stripping of the GC while it was still inside its parent dwarf galaxy; (b) the cocoon comprises debris from the parent dwarf galaxy; (c) an initially thin GC tidal stream was heated by impacts from dark subhalos in the Milky Way; (d) an initially thin GC stream was heated by a massive Sagittarius dwarf galaxy; or a combination of some of these. Future DESI spectroscopy and detailed modeling may enable us to distinguish between these possible origins.
Keywords
- Atomic spectroscopy
- Spectroscopy
- Milky Way dark matter halo
- Dark matter
- Stellar streams
- Milky Way dynamics
