TY - JOUR
T1 - NGC 147, NGC 185 and CassII: a genetic approach to orbital properties, star formation and tidal debris
AU - Arias, Veronica
AU - Guglielmo, Magda
AU - Fernando, Nuwanthika
AU - Lewis, Geraint F.
AU - Bland-Hawthorn, Joss
AU - Bate, Nicholas F.
AU - Conn, Anthony
AU - Irwin, Mike J.
AU - Ferguson, Annette M. N.
AU - Ibata, Rodrigo A.
AU - McConnachie, Alan W.
AU - Martin, Nicolas
PY - 2016/2/1
Y1 - 2016/2/1
N2 - NGC 147, NGC 185 and Cassiopeia II (CassII) have similar positions in
the sky, distances and measured line-of-sight velocities. This proximity
in phase space suggests that these three satellites of M31 form a
subgroup within the Local Group. Nevertheless, the differences in their
star formation history and interstellar medium, and the recent discovery
of a stellar stream in NGC 147, combined with the lack of tidal features
in the other two satellites, are all indications of complex and diverse
interactions between M31 and these three satellites. We use a genetic
algorithm to explore the different orbits that these satellites can have
and select six sets of orbits that could best explain the observational
features of the NGC 147, NGC 185 and CassII satellites. The parameters
of these orbits are then used as a starting point for N-body
simulations. We present models for which NGC 147, NGC 185 and CassII are
a bound group for a total time of at least 1 Gyr but still undergo
different interactions with M31 and as a result NGC 147 has a clear
stellar stream, whereas the other two satellites have no significant
tidal features. This result shows that it is possible to find solutions
that reproduce the contrasting properties of the satellites and for
which NGC 147-NGC 185-CassII have been gravitationally bound.
AB - NGC 147, NGC 185 and Cassiopeia II (CassII) have similar positions in
the sky, distances and measured line-of-sight velocities. This proximity
in phase space suggests that these three satellites of M31 form a
subgroup within the Local Group. Nevertheless, the differences in their
star formation history and interstellar medium, and the recent discovery
of a stellar stream in NGC 147, combined with the lack of tidal features
in the other two satellites, are all indications of complex and diverse
interactions between M31 and these three satellites. We use a genetic
algorithm to explore the different orbits that these satellites can have
and select six sets of orbits that could best explain the observational
features of the NGC 147, NGC 185 and CassII satellites. The parameters
of these orbits are then used as a starting point for N-body
simulations. We present models for which NGC 147, NGC 185 and CassII are
a bound group for a total time of at least 1 Gyr but still undergo
different interactions with M31 and as a result NGC 147 has a clear
stellar stream, whereas the other two satellites have no significant
tidal features. This result shows that it is possible to find solutions
that reproduce the contrasting properties of the satellites and for
which NGC 147-NGC 185-CassII have been gravitationally bound.
KW - methods: numerical
KW - galaxies: dwarf
KW - galaxies: individual: NGC 147
KW - galaxies: individual: NGC 185
KW - galaxies: individual: CassII
KW - Local Group
U2 - 10.1093/mnras/stv2781
DO - 10.1093/mnras/stv2781
M3 - Article
SN - 0035-8711
VL - 456
SP - 1654
EP - 1665
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -