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Misaligned streamers around a Galactic Centre black hole from a single cloud's infall

Lucas, W. E. ; Bonnell, I. A. ; Davies, Melvyn B LU and Rice, W. K. M. (2013) In Monthly Notices of the Royal Astronomical Society 433(1). p.353-365
Abstract
We follow the near radial infall of a prolate cloud on to a 4 x 10(6) M-circle dot supermassive black hole in the Galactic Centre using smoothed particle hydrodynamics. We show that a prolate cloud oriented perpendicular to its orbital plane naturally produces a spread in angular momenta in the gas which can translate into misaligned discs as is seen in the young stars orbiting Sagittarius A*. A turbulent or otherwise highly structured cloud is necessary to avoid cancelling too much angular momentum through shocks at closest approach. Our standard model of a 2 x 10(4) M-circle dot gas cloud brought about the formation of a disc within 0.3 pc from the black hole and a larger, misaligned streamer at 0.5 pc. A total of 1.5 x 10(4) M-circle... (More)
We follow the near radial infall of a prolate cloud on to a 4 x 10(6) M-circle dot supermassive black hole in the Galactic Centre using smoothed particle hydrodynamics. We show that a prolate cloud oriented perpendicular to its orbital plane naturally produces a spread in angular momenta in the gas which can translate into misaligned discs as is seen in the young stars orbiting Sagittarius A*. A turbulent or otherwise highly structured cloud is necessary to avoid cancelling too much angular momentum through shocks at closest approach. Our standard model of a 2 x 10(4) M-circle dot gas cloud brought about the formation of a disc within 0.3 pc from the black hole and a larger, misaligned streamer at 0.5 pc. A total of 1.5 x 10(4) M-circle dot of gas formed these structures. Our exploration of the simulation parameter space showed that when star formation occurred, it resulted in top-heavy initial mass functions with stars on eccentric orbits with semi-major axes 0.02-0.3 pc and inclinations following the gas discs and streamers. We suggest that the single event of an infalling prolate cloud can explain the occurrence of multiple misaligned discs of young stars. (Less)
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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
stars: formation, accretion discs, accretion, hydrodynamics, Galaxy:, centre
in
Monthly Notices of the Royal Astronomical Society
volume
433
issue
1
pages
353 - 365
publisher
Oxford University Press
external identifiers
  • wos:000321461200029
  • scopus:84880435461
ISSN
1365-2966
DOI
10.1093/mnras/stt727
language
English
LU publication?
yes
id
f1b42925-bcca-4286-9b98-0a3f35b24d55 (old id 4039630)
date added to LUP
2016-04-01 10:14:30
date last changed
2024-02-21 11:44:44
@article{f1b42925-bcca-4286-9b98-0a3f35b24d55,
  abstract     = {{We follow the near radial infall of a prolate cloud on to a 4 x 10(6) M-circle dot supermassive black hole in the Galactic Centre using smoothed particle hydrodynamics. We show that a prolate cloud oriented perpendicular to its orbital plane naturally produces a spread in angular momenta in the gas which can translate into misaligned discs as is seen in the young stars orbiting Sagittarius A*. A turbulent or otherwise highly structured cloud is necessary to avoid cancelling too much angular momentum through shocks at closest approach. Our standard model of a 2 x 10(4) M-circle dot gas cloud brought about the formation of a disc within 0.3 pc from the black hole and a larger, misaligned streamer at 0.5 pc. A total of 1.5 x 10(4) M-circle dot of gas formed these structures. Our exploration of the simulation parameter space showed that when star formation occurred, it resulted in top-heavy initial mass functions with stars on eccentric orbits with semi-major axes 0.02-0.3 pc and inclinations following the gas discs and streamers. We suggest that the single event of an infalling prolate cloud can explain the occurrence of multiple misaligned discs of young stars.}},
  author       = {{Lucas, W. E. and Bonnell, I. A. and Davies, Melvyn B and Rice, W. K. M.}},
  issn         = {{1365-2966}},
  keywords     = {{stars: formation; accretion discs; accretion; hydrodynamics; Galaxy:; centre}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{353--365}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{Misaligned streamers around a Galactic Centre black hole from a single cloud's infall}},
  url          = {{http://dx.doi.org/10.1093/mnras/stt727}},
  doi          = {{10.1093/mnras/stt727}},
  volume       = {{433}},
  year         = {{2013}},
}