[Speaker1]
Takafumi Tsukui,
SOKENDAI 3rd year (D1),
(Supervisor: Satoru Iguchi, Hiroshi Nagai, Yuichi Matsuda)
[Title1]
Galactic Dynamics and Dark Matter Profile of NGC1380 with ALMA and VLT/MUSE.
[Abstract1]
ALMA’s high resolution and high sensitivity images enable us to
obtain kinematics of molecular gas in the center of early-type galaxies (~1kpc)
complementarily to the stellar dynamics obtained with optical IFU instrument.
The cold molecular gas dynamics is a powerful tracer of mass distribution of
galaxies because the velocity dispersion is low(~10km/s) and the simple
rotational model is applicable. To understand the interaction between dark
matter and baryonic matter in the galaxy evolution history, it is fundamental
to measure dark matter distribution in galaxies. However, it is difficult to
derive the dark matter profile in the central region of early-type galaxies
because of the lack of neutral hydrogen gas in early-type galaxies and the
degeneracy between dynamical stellar M/L and dark matter distribution. To
resolve this difficulty, we conducted a combined analysis of ALMA cold
molecular gas kinematics data and MUSE stellar kinematics data of early-type
fast rotator galaxy NGC1380. Our strategy is to measure BH mass and stellar
mass well in the central region (~radius of 6”, 500pc) with the cold gas
kinematics. Then we derive dark matter profile with the stellar kinematics
which is available in a wide field of view(~radius of 120’’, 10kpc) with the help
of information of the central cold gas modeling. Dynamical measurement of
stellar M/L and BH mass is conducted with ALMA high angular resolution data
(0.24”×0.18” ~ 21pc×16pc where BH sphere of influence of the resulted BH mass
is 0.37”~ 33pc). Simple gas rotational disk model reproduce observed data cube
well. The obtained BH mass of 3.38×10^8^{+0.30}_{-0.24} solar masses is close
to the estimated value of 3.9×10^8 solar masses from the empirical M – sigma
relation. With Jeans Anisotropic Models (JAM; Cappellari 2008) of stellar
kinematics, we found that the substantial dark matter halo needs to exist to
maintain flat velocity profile at large radius. However, the mass model
obtained with ALMA cold gas modeling cannot reproduce the central high-velocity
dispersion peak in the stellar kinematics data (~10” 900pc ), which may
indicate several possibilities including the steep M/L variation and hidden
non-axisymmetric bar structure. We obtained dark matter profile by using
information from the central gas rotational disk model as a prior knowledge
with Bayesian inference. The obtained central slope of the dark matter was
gamma=0.45^{+0.11}_{-0.10} which is lower than 1.0 NFW profile predict.
[Speaker2]
Shishido, Takaharu,
SOKENDAI 3rd year (D1),
(Supervisor:Takayuki tomaru, Yoichi Aso, Ryutaro Takahashi)
[Title2]
A study of the sapphire suspension fiber
for cryogenic gravitational wave detector KAGRA