期刊
ASTROPHYSICAL JOURNAL
卷 911, 期 2, 页码 -出版社
IOP Publishing Ltd
DOI: 10.3847/1538-4357/abeb18
关键词
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资金
- NASA through Hubble Fellowship - Space Telescope Science Institute [HST-HF2-51439.001, HST-HF2-51393.001]
- NASA [NAS5-26555]
- NSF [AST-1813881, AST-1909584]
- Heising-Simons foundation grant [2018-1030]
- Science & Technology Facilities Council (STFC)
- European Research Council (ERC)
- U.S. Department of Energy
- U.S. National Science Foundation
- Ministry of Science and Education of Spain
- Science and Technology Facilities Council of the United Kingdom
- Higher Education Funding Council for England
- National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign
- Kavli Institute of Cosmological Physics at the University of Chicago
- Center for Cosmology and Astro-Particle Physics at The Ohio State University
- Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University
- Financiadora de Estudos e Projetos
- Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro
- Conselho Nacional de Desenvolvimento Cientifico e Tecnologico
- Ministerio da Ciencia, Tecnologia e Inovacao
- Deutsche Forschungsgemeinschaft
- Argonne National Laboratory
- University of California at Santa Cruz
- University of Cambridge
- Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid
- University of Chicago
- University College London
- DES-Brazil Consortium
- University of Edinburgh
- Eidgenossische Technische Hochschule (ETH) Zurich
- Fermi National Accelerator Laboratory
- University of Illinois at Urbana-Champaign
- Institut de Ciencies de l'Espai (IEEC/CSIC)
- Institut de Fisica d'Altes Energies
- Lawrence Berkeley National Laboratory
- Ludwig-Maximilians Universitat Munchen and the associated Excellence Cluster Universe
- University of Michigan
- National Optical Astronomy Observatory
- University of Nottingham
- Ohio State University
- OzDES Membership Consortium
- University of Pennsylvania
- University of Portsmouth
- SLAC National Accelerator Laboratory
- Stanford University
- University of Sussex
- Texas AM University
- Max Planck Institute for Astronomy, Heidelberg
- Max Planck Institute for Extraterrestrial Physics, Garching
- Johns Hopkins University
- Durham University
- Queen's University Belfast
- Las Cumbres Observatory Global Telescope Network Incorporated
- National Central University of Taiwan
- Space Telescope Science Institute
- National Aeronautics and Space Administration [NNX08AR22G]
- National Science Foundation [AST-1238877]
- University of Maryland
- Eotvos Lorand University (ELTE)
- Los Alamos National Laboratory
- Gordon and Betty Moore Foundation
The study reveals that the ATLAS and Aliqa Uma streams are likely to be one stream with discontinuity and broadening features. Only an encounter with the Sagittarius dwarf can create a similar kink feature. The gaps in the ATLAS component are likely formed by small mass perturbers, impacting the distant AAU stream with severe variations in density and track.
We present the first spectroscopic measurements of the ATLAS and Aliqa Uma streams from the Southern Stellar Stream Spectroscopic Survey (S (5)), in combination with the photometric data from the Dark Energy Survey and astrometric data from Gaia. From the coherence of spectroscopic members in radial velocity and proper motion, we find that these two systems are extremely likely to be one stream with discontinuity in morphology and density on the sky (the kink feature). We refer to this entire stream as the ATLAS-Aliqa Uma stream, or the AAU stream. We perform a comprehensive exploration of the effect of baryonic substructures and find that only an encounter with the Sagittarius dwarf similar to 0.5 Gyr ago can create a feature similar to the observed kink. In addition, we also identify two gaps in the ATLAS component associated with the broadening in the stream width (the broadening feature). These gaps have likely been created by small mass perturbers, such as dark matter halos, as the AAU stream is the most distant cold stream known with severe variations in both the stream surface density and the stream track on the sky. With the stream track, stream distance, and kinematic information, we determine the orbit of the AAU stream and find that it has been affected by the Large Magellanic Cloud, resulting in a misalignment between the proper motion and stream track. Together with the Orphan-Chenab Stream, AAU is the second stream pair that has been found to be a single stream separated into two segments by external perturbation.
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