We present a 6D map of the Orphan–Chenab (OC) stream by combining the data from Southern Stellar Stream Spectroscopic Survey (S5) and Gaia. We reconstruct the proper motion, radial velocity, distance, on-sky track, and stellar density along the stream with spline models. The stream has a total luminosity of MV = -8.2 and metallicity of [Fe/H] = -1.9, similar to classical Milky Way (MW) satellites like Draco. The stream shows drastic changes in its physical width varying from 200 pc to 1kpc, but a constant line-of-sight velocity dispersion of 5 km s-1. Despite the large apparent variation in the stellar number density along the stream, the flow rate of stars along the stream is remarkably constant. We model the 6D stream track by a Lagrange-point stripping method with a flexible MW potential in the presence of a moving extended Large Magellanic Cloud (LMC). This allows us to constrain the mass profile of the MW within the distance range 15.6 < r < 55∙5 kpc, with the best measured enclosed mass of (2.85 ± 0.1) X 1011 M⊙ within 32.4 kpc. Our stream measurements are highly sensitive to the LMC mass profile with the most precise measurement of its enclosed mass made at 32.8 kpc, 7.02 ± 0.9) X 1011 M⊙. We also detect that the LMC dark matter halo extends to at least 53 kpc. The fitting of the OC stream allows us to constrain the past LMC trajectory and the degree of dynamical friction it experienced. We demonstrate that the stars in the OC stream show large energy and angular momentum spreads caused by LMC perturbation.
Koposov, Sergey E., et al. "<em>S</em><sup>5</sup>: Probing the Milky Way and Magellanic Clouds potentials with the 6D map of the Orphan–Chenab stream." Monthly Notices of the Royal Astronomical Society, vol. 521, no. 4, Feb. 2023. https://doi.org/10.1093/mnras/stad551
Koposov, Sergey E., Erkal, Denis, Li, Ting S., Da Costa, Gary S., Cullinane, Lara R., Ji, Alexander P., Kuehn, Kyler, Lewis, Geraint F., Pace, Andrew B., Shipp, Nora, Zucker, Daniel B., Bland-Hawthorn, Joss, Lilleengen, Sophia, & Martell, Sarah L. (2023). <em>S</em><sup>5</sup>: Probing the Milky Way and Magellanic Clouds potentials with the 6D map of the Orphan–Chenab stream. Monthly Notices of the Royal Astronomical Society, 521(4). https://doi.org/10.1093/mnras/stad551
Koposov, Sergey E., Erkal, Denis, Li, Ting S., et al., "<em>S</em><sup>5</sup>: Probing the Milky Way and Magellanic Clouds potentials with the 6D map of the Orphan–Chenab stream," Monthly Notices of the Royal Astronomical Society 521, no. 4 (2023), https://doi.org/10.1093/mnras/stad551
@article{osti_2422857,
author = {Koposov, Sergey E. and Erkal, Denis and Li, Ting S. and Da Costa, Gary S. and Cullinane, Lara R. and Ji, Alexander P. and Kuehn, Kyler and Lewis, Geraint F. and Pace, Andrew B. and Shipp, Nora and others},
title = {<em>S</em><sup>5</sup>: Probing the Milky Way and Magellanic Clouds potentials with the 6D map of the Orphan–Chenab stream},
annote = {We present a 6D map of the Orphan–Chenab (OC) stream by combining the data from Southern Stellar Stream Spectroscopic Survey (S5) and Gaia. We reconstruct the proper motion, radial velocity, distance, on-sky track, and stellar density along the stream with spline models. The stream has a total luminosity of MV = -8.2 and metallicity of [Fe/H] = -1.9, similar to classical Milky Way (MW) satellites like Draco. The stream shows drastic changes in its physical width varying from 200 pc to 1kpc, but a constant line-of-sight velocity dispersion of 5 km s-1. Despite the large apparent variation in the stellar number density along the stream, the flow rate of stars along the stream is remarkably constant. We model the 6D stream track by a Lagrange-point stripping method with a flexible MW potential in the presence of a moving extended Large Magellanic Cloud (LMC). This allows us to constrain the mass profile of the MW within the distance range 15.6 11 M⊙ within 32.4 kpc. Our stream measurements are highly sensitive to the LMC mass profile with the most precise measurement of its enclosed mass made at 32.8 kpc, 7.02 ± 0.9) X 1011 M⊙. We also detect that the LMC dark matter halo extends to at least 53 kpc. The fitting of the OC stream allows us to constrain the past LMC trajectory and the degree of dynamical friction it experienced. We demonstrate that the stars in the OC stream show large energy and angular momentum spreads caused by LMC perturbation.},
doi = {10.1093/mnras/stad551},
url = {https://www.osti.gov/biblio/2422857},
journal = {Monthly Notices of the Royal Astronomical Society},
issn = {ISSN 0035-8711},
number = {4},
volume = {521},
place = {United States},
publisher = {Oxford University Press},
year = {2023},
month = {02}}
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP)
Contributing Organization:
S5 Collaboration
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
2422857
Journal Information:
Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 4 Vol. 521; ISSN 0035-8711