apjThe Astrophysical JournalAPJAstrophys. J.0004-637X1538-4357The American Astronomical Societyapjac399b10.3847/1538-4357/ac399bac399bAAS35259310Galaxies and CosmologyFrom the Fire: A Deeper Look at the Phoenix Stream0000-0001-6584-6144TavangarK.12ktavangar@flatironinstitute.org0000-0001-6957-1627FergusonP.340000-0003-2497-091XShippN.1250000-0001-8251-933XDrlica-WagnerA.1260000-0003-2644-135XKoposovS.7890000-0002-8448-5505ErkalD.100000-0002-1322-3153BalbinotE.110000-0002-9370-8360García-BellidoJ.120000-0003-0120-0808KuehnK.13140000-0003-3081-9319LewisG. F.150000-0002-9110-6163LiT. S.161718550000-0003-3519-4004MauS.19200000-0002-6021-8760PaceA. B.210000-0001-5805-5766RileyA. H.4AbbottT. M. C.220000-0001-5679-6747AguenaM.230000-0002-7069-7857AllamS.6Andrade-OliveiraF.23240000-0002-0609-3987AnnisJ.60000-0002-3602-3664BertinE.25260000-0002-8458-5047BrooksD.270000-0003-1866-1950BurkeD. L.20280000-0003-3044-5150Carnero RosellA.230000-0002-4802-3194Carrasco KindM.29300000-0002-3130-0204CarreteroJ.310000-0001-8158-1449CostanziM.323334da CostaL. N.2335PereiraM. E. S.36370000-0001-8318-6813De VicenteJ.380000-0002-8357-7467DiehlH. T.6EverettS.39FerreroI.400000-0002-2367-5049FlaugherB.60000-0003-4079-3263FriemanJ.260000-0001-9632-0815GaztanagaE.41420000-0001-6942-2736GerdesD. W.36430000-0003-3270-7644GruenD.44GruendlR. A.29300000-0003-3023-8362GschwendJ.23350000-0003-0825-0517GutierrezG.6HintonS. R.45HollowoodD. L.390000-0002-6550-2023HonscheidK.46470000-0001-5160-4486JamesD. J.480000-0003-2511-0946KuropatkinN.60000-0001-9856-9307MaiaM. A. G.23350000-0003-0710-9474MarshallJ. L.40000-0002-1372-2534MenanteauF.29300000-0002-6610-4836MiquelR.3149MorganR.30000-0003-2120-1154OgandoR. L. C.350000-0002-6011-0530PalmeseA.260000-0003-1339-2683Paz-ChinchónF.8290000-0001-9186-6042PieresA.23350000-0002-2598-0514Plazas MalagónA. A.50Rodriguez-MonroyM.380000-0002-9646-8198SanchezE.38ScarpineV.6SerranoS.41420000-0002-1831-1953Sevilla-NoarbeI.380000-0002-3321-1432SmithM.510000-0002-7047-9358SuchytaE.52SwansonM. E. C.290000-0003-1704-0781TarleG.360000-0001-7836-2261ToC.192028VargaT. N.53540000-0002-7123-8943WalkerA. R.22 (DES Collaboration) Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637, USA; ktavangar@flatironinstitute.org Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637, USA Physics Department, 2320 Chamberlin Hall, University of Wisconsin−Madison, 1150 University Avenue Madison, WI 53706-1390, USA George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Ave., Cambridge, MA 02139, USA Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510, USA 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 Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK Department of Physics, University of Surrey, Guildford, GU2 7XH, UK Kapteyn Astronomical Institute, University of Groningen, Postbus 800, NL-9700AV Groningen, The Netherlands Instituto de Fisica Teorica UAM/CSIC, Universidad Autonoma de Madrid, E-28049 Madrid, Spain Lowell Observatory, 1400 Mars Hill Rd., Flagstaff, AZ 86001, USA Australian Astronomical Optics, Macquarie University, North Ryde, NSW 2113, Australia Sydney Institute for Astronomy, School of Physics, A28, The University of Sydney, NSW 2006, Australia Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101, USA Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, USA Kavli Institute for Particle Astrophysics & Cosmology, P.O. Box 2450, Stanford University, Stanford, CA 94305, USA Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15312, USA Cerro Tololo Inter-American Observatory, NSF's National Optical-Infrared Astronomy Research Laboratory, Casilla 603, La Serena, Chile Laboratório Interinstitucional de e-Astronomia—LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ—20921-400, Brazil Instituto de Física Teórica, Universidade Estadual Paulista, São Paulo, Brazil CNRS, UMR 7095, Institut d’Astrophysique de Paris, F-75014, Paris, France Sorbonne Universités, UPMC Univ Paris 06, UMR 7095, Institut d’Astrophysique de Paris, F-75014, Paris, France Department of Physics & Astronomy, University College London, Gower Street, London, WC1E 6BT, UK SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA Center for Astrophysical Surveys, National Center for Supercomputing Applications, 1205 West Clark St., Urbana, IL 61801, USA Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W. Green Street, Urbana, IL 61801, USA Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, E-08193 Bellaterra (Barcelona) Spain Astronomy Unit, Department of Physics, University of Trieste, via Tiepolo 11, I-34131 Trieste, Italy INAF-Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, I-34143 Trieste, Italy Institute for Fundamental Physics of the Universe, Via Beirut 2, I-34014 Trieste, Italy Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ—20921-400, Brazil Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg, Germany Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain Santa Cruz Institute for Particle Physics, Santa Cruz, CA 95064, USA Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo, Norway Institut d’Estudis Espacials de Catalunya (IEEC), E-08034 Barcelona, Spain Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, E-08193 Barcelona, Spain Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA Faculty of Physics, Ludwig-Maximilians-Universität, Scheinerstr. 1, D-81679 Munich, Germany School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210, USA Department of Physics, The Ohio State University, Columbus, OH 43210, USA Center for Astrophysics ∣ Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA Institució Catalana de Recerca i Estudis Avançats, E-08010 Barcelona, Spain Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544, USA School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, D-85748 Garching, Germany Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians Universität München, Scheinerstr. 1, D-81679 München, Germany

NHFP Einstein Fellow.

0122022310120223101202292521187102021121120211211202115112021© 2022. The Author(s). Published by the American Astronomical Society.2022 Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Abstract

We use 6 yr of data from the Dark Energy Survey to perform a detailed photometric characterization of the Phoenix stellar stream, a 15° long, thin, dynamically cold, low-metallicity stellar system in the Southern Hemisphere. We use natural splines, a nonparametric modeling technique, to simultaneously fit the stream track, width, and linear density. This updated stream model allows us to improve measurements of the heliocentric distance (17.4 ± 0.1 (stat.) ±0.8 (sys.) kpc) and distance gradient (−0.009 ± 0.006 kpc deg−1) of Phoenix, which corresponds to a small change of 0.13 ± 0.09 kpc in heliocentric distance along the length of the stream. We measure linear intensity variations on degree scales, as well as deviations in the stream track on ∼2° scales, suggesting that the stream may have been disturbed during its formation and/or evolution. We recover three peaks and one gap in linear intensity along with fluctuations in the stream track. Compared to other thin streams, the Phoenix stream shows more fluctuations and, consequently, the study of Phoenix offers a unique perspective on gravitational perturbations of stellar streams. We discuss possible sources of perturbations to Phoenix, including baryonic structures in the Galaxy and dark matter subhalos.

CosmologyDark matterStellar streamsGalaxy structureAstronomy data modelingMilky Way dynamicsNational Science Foundation (NSF)https://doi.org/10.13039/100000001 AST-1138766National Science Foundation (NSF)https://doi.org/10.13039/100000001 AST-1536171ccc0004-637X/22/118+14$33.00crossmarkyes