Hidden depths in the local Universe: The Stellar Stream Legacy Survey

¹ Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía, 18080 Granada, Spain
e-mail: dmartinez@iaa.es
² Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12–14, 69120 Heidelberg, Germany
³ Institute of Astronomy and Department of Physics, National Tsing Hua University, Kuang Fu Rd. Sec. 2, Hsinchu 30013, Taiwan
⁴ Center for Informatics and Computation in Astronomy, National Tsing Hua University, Kuang Fu Rd. Sec. 2, Hsinchu 30013, Taiwan
⁵ Max Planck Institut für Astronomie Königstuhl 17, 69117 Heidelberg, Germany
⁶ Department of Physics, University of Surrey, Guildford GU2, 7XH, UK
⁷ Center for Cosmology and Particle Physics, Department of Physics, New York University, 726 Broadway, New York, NY 10003, USA
⁸ Siena College, Department of Physics & Astronomy, 515 Loudon Road, Loudonville, NY 12211, USA
⁹ Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokio, Chiba 277-8583, Japan
¹⁰ IPAC, Mail Code 314-6, Caltech, 1200 E. California BLVd., Pasadena, CA 91125, USA
¹¹ Instituto de Astrofísica de Canarias (IAC), Calle Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
¹² Facultad de Física, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez s/n, 38200 La Laguna, Tenerife, Spain
¹³ Perimeter Institute for Theoretical Physics, 31 Caroline St N, Waterloo, Canada
¹⁴ Special Astrophysical Observatory of the Russian Academy of Sciences, Nizhnij Arkhyz 369167, Russia
¹⁵ NASA Ames Research Center, Moffett Field, CA 94035, USA
¹⁶ UAI – Unione Astrofili Italiani/P.I. Sezione Nazionale di Ricerca Profondo Cielo, 72024 Oria, Italy
¹⁷ National Centre for Nuclear Research, ul. Pasteura 7, 02-093 Warszawa, Poland
¹⁸ Departamento de Física de la Tierra y Astrofísica, Universidad Complutense de Madrid, Plaza de las Ciencias, 28040 Madrid, Spain
¹⁹ AIM, CEA, CNRS, Université Paris-Saclay, Université de Paris, Orme des Merisiers, 91191 Gif-sur-Yvette, France
²⁰ Institute of Space Sciences (ICE,CSIC), Campus UAB, Carrer de Magrans, 08193 Barcelona, Spain
²¹ Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE, UK
²² Astrophysics Source Code Library, University of Maryland, 4254, Stadium Drive College Park, MD 20742, USA
²³ Leibniz-Institut für Astrophysik Postdam (AIP), An der Sternwarte 16, 14482 Postdam, Germany
²⁴ NSF’s National Optical-Infrared Astronomy Research Laboratory, 950 N. Cherry Ave., Tucson, AZ 85719, USA
²⁵ Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA
²⁶ Department of Physics & Astronomy, University of Wyoming, 1000 E. University, Dept. 3905, Laramie, WY 82071, USA
²⁷ Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
²⁸ Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Unidad Asociada al CSIC, Plaza San Juan 1, 44001 Teruel, Spain

Received: 19 September 2022
Accepted: 29 November 2022

Abstract

Context. Mergers and tidal interactions between massive galaxies and their dwarf satellites are a fundamental prediction of the Lambda-cold dark matter cosmology. These events are thought to provide important observational diagnostics of non-linear structure formation. Stellar streams in the Milky Way and Andromeda are spectacular evidence for ongoing satellite disruption. However, constructing a statistically meaningful sample of tidal streams beyond the Local Group has proven a daunting observational challenge, and the full potential for deepening our understanding of galaxy assembly using stellar streams has yet to be realised.

Aims. Here we introduce the Stellar Stream Legacy Survey, a systematic imaging survey of tidal features associated with dwarf galaxy accretion around a sample of ∼3100 nearby galaxies within z ∼ 0.02, including about 940 Milky Way analogues.

Methods. Our survey exploits public deep imaging data from the DESI Legacy Imaging Surveys, which reach surface brightness as faint as ∼29 mag arcsec⁻² in the r band. As a proof of concept of our survey, we report the detection and broad-band photometry of 24 new stellar streams in the local Universe.

Results. We discuss how these observations can yield new constraints on galaxy formation theory through comparison to mock observations from cosmological galaxy simulations. These tests will probe the present-day mass assembly rate of galaxies, the stellar populations and orbits of satellites, the growth of stellar halos, and the resilience of stellar disks to satellite bombardment.