TY - JOUR
T1 - All-sky dynamical response of the Galactic halo to the Large Magellanic Cloud
AU - Conroy, Charlie
AU - Naidu, Rohan P.
AU - Garavito-Camargo, Nicolás
AU - Besla, Gurtina
AU - Zaritsky, Dennis
AU - Bonaca, Ana
AU - Johnson, Benjamin D.
N1 - Funding Information: Acknowledgements C.C. is partially supported by the Packard Foundation. R.P.N. acknowledges an Ashford Fellowship and Peirce Fellowship granted by Harvard University. G.B. and N.G.-C. are supported by HST grant AR 15004, NASA ATP grant 17-ATP17-0006, NSF CAREER AST-1941096. A.B. acknowledges support from NASA through HST grant HST-GO-15930. All the simulations were run on El-Gato supercomputer, which was supported by the National Science Foundation under grant no. 1228509. We have made use of data from the European Space Agency mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC; see http://www.cosmos.esa.int/web/ gaia/dpac/consortium). Funding for DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/ California Institute of Technology, and NEOWISE, which is a project of the Jet Propulsion Laboratory/ California Institute of Technology. WISE and NEOWISE are funded by the National Aeronautics and Space Administration. Publisher Copyright: © 2021, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2021/4/22
Y1 - 2021/4/22
N2 - Gravitational interactions between the Large Magellanic Cloud (LMC) and the stellar and dark matter halo of the Milky Way are expected to give rise to disequilibrium phenomena in the outer Milky Way1–7. A local wake is predicted to trail the orbit of the LMC, and a large-scale overdensity is predicted to exist across a large area of the northern Galactic hemisphere. Here we report the detection of both the local wake and northern overdensity (hereafter the ‘collective response’) in a map of the Galaxy based on 1,301 stars at Galactocentric distances between 60 and 100 kiloparsecs. The location of the wake is in good agreement with an N-body simulation that includes the dynamical effect of the LMC on the Milky Way halo. The density contrast of the wake and collective response are stronger in the data than in the simulation. The detection of a strong local wake is independent evidence that the Magellanic clouds are on their first orbit around the Milky Way. The wake traces the path of the LMC, which will provide insight into the orbit of the LMC, which in turn is a sensitive probe of the mass of the LMC and the Milky Way. These data demonstrate that the outer halo is not in dynamical equilibrium, as is often assumed. The morphology and strength of the wake could be used to test the nature of dark matter and gravity.
AB - Gravitational interactions between the Large Magellanic Cloud (LMC) and the stellar and dark matter halo of the Milky Way are expected to give rise to disequilibrium phenomena in the outer Milky Way1–7. A local wake is predicted to trail the orbit of the LMC, and a large-scale overdensity is predicted to exist across a large area of the northern Galactic hemisphere. Here we report the detection of both the local wake and northern overdensity (hereafter the ‘collective response’) in a map of the Galaxy based on 1,301 stars at Galactocentric distances between 60 and 100 kiloparsecs. The location of the wake is in good agreement with an N-body simulation that includes the dynamical effect of the LMC on the Milky Way halo. The density contrast of the wake and collective response are stronger in the data than in the simulation. The detection of a strong local wake is independent evidence that the Magellanic clouds are on their first orbit around the Milky Way. The wake traces the path of the LMC, which will provide insight into the orbit of the LMC, which in turn is a sensitive probe of the mass of the LMC and the Milky Way. These data demonstrate that the outer halo is not in dynamical equilibrium, as is often assumed. The morphology and strength of the wake could be used to test the nature of dark matter and gravity.
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U2 - 10.1038/s41586-021-03385-7
DO - 10.1038/s41586-021-03385-7
M3 - Article
C2 - 33883729
SN - 0028-0836
VL - 592
SP - 534
EP - 536
JO - Nature
JF - Nature
IS - 7855
ER -