Thermal transpiration in molecular gas

2020 ◽  
Vol 32 (8) ◽  
pp. 082005 ◽  
Author(s):  
Peng Wang ◽  
Wei Su ◽  
Lei Wu
Keyword(s):  
Molecular Gas ◽  
Thermal Transpiration

scholarly journals Poiseuille and thermal transpiration flows of a highly rarefied gas: over-concentration in the velocity distribution function

2011 ◽  
Vol 669 ◽  
pp. 242-259 ◽  
Author(s):  
SHIGERU TAKATA ◽  
HITOSHI FUNAGANE
Keyword(s):  
Mass Flow ◽  
Hard Sphere ◽  
Rarefied Gas ◽  
Velocity Distribution Function ◽  
Molecular Gas ◽  
Approximation Procedure ◽  
Molecular Models ◽  
Iterative Approximation ◽  
Thermal Transpiration ◽  
Linearized Boltzmann Equation

Poiseuille and thermal transpiration flows of a highly rarefied gas are investigated on the basis of the linearized Boltzmann equation, with a special interest in the over-concentration of molecules on velocities parallel to the walls. An iterative approximation procedure with an explicit error estimate is presented, by which the structure of the over-concentration is clarified. A numerical computation on the basis of the procedure is performed for a hard-sphere molecular gas to construct a database that promptly gives the induced net mass flow for an arbitrary value of large Knudsen numbers. An asymptotic formula of the net mass flow is also presented for molecular models belonging to Grad's hard potential. Finally, the resemblance of the profiles between the heat flow of the Poiseuille flow and the flow velocity of the thermal transpiration is pointed out. The reason is also given.

Central kiloparsec of NGC 1326 observed with SINFONI

2020 ◽  
Vol 638 ◽  
pp. A53
Author(s):  
Nastaran Fazeli ◽  
Gerold Busch ◽  
Andreas Eckart ◽  
Françoise Combes ◽  
Persis Misquitta ◽  
...  
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Near Infrared ◽  
Velocity Fields ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Stellar Content ◽  
Stellar Rotation ◽  
Supermassive Black Hole ◽  
Integral Field Spectrograph

Gas inflow processes in the vicinity of galactic nuclei play a crucial role in galaxy evolution and supermassive black hole growth. Exploring the central kiloparsec of galaxies is essential to shed more light on this subject. We present near-infrared H- and K-band results of the nuclear region of the nearby galaxy NGC 1326, observed with the integral-field spectrograph SINFONI mounted on the Very Large Telescope. The field of view covers 9″ × 9″ (650 × 650 pc2). Our work is concentrated on excitation conditions, morphology, and stellar content. The nucleus of NGC 1326 was classified as a LINER, however in our data we observed an absence of ionised gas emission in the central r ∼ 3″. We studied the morphology by analysing the distribution of ionised and molecular gas, and thereby detected an elliptically shaped, circum-nuclear star-forming ring at a mean radius of 300 pc. We estimate the starburst regions in the ring to be young with dominating ages of < 10 Myr. The molecular gas distribution also reveals an elongated east to west central structure about 3″ in radius, where gas is excited by slow or mild shock mechanisms. We calculate the ionised gas mass of 8 × 105 M⊙ completely concentrated in the nuclear ring and the warm molecular gas mass of 187 M⊙, from which half is concentrated in the ring and the other half in the elongated central structure. The stellar velocity fields show pure rotation in the plane of the galaxy. The gas velocity fields show similar rotation in the ring, but in the central elongated H2 structure they show much higher amplitudes and indications of further deviation from the stellar rotation in the central 1″ aperture. We suggest that the central 6″ elongated H2 structure might be a fast-rotating central disc. The CO(3–2) emission observations with the Atacama Large Millimeter/submillimeter Array reveal a central 1″ torus. In the central 1″ of the H2 velocity field and residual maps, we find indications for a further decoupled structure closer to a nuclear disc, which could be identified with the torus surrounding the supermassive black hole.

Kinetics of a nonequilibrium molecular gas

1988 ◽  
Vol 155 (7) ◽  
pp. 545-545
Author(s):  
Boris M. Smirnov
Keyword(s):  
Molecular Gas ◽  
Kinetics Of

Morphology and Energetics of the Molecular Gas within a Core and a Diffuse Region in the Filamentary Dark Cloud GF 9

2000 ◽  
Vol 120 (1) ◽  
pp. 393-406 ◽  
Author(s):  
David R. Ciardi ◽  
Charles E. Woodward ◽  
Dan P. Clemens ◽  
David E. Harker ◽  
Richard J. Rudy
Keyword(s):  
Molecular Gas ◽  
Dark Cloud ◽  
Diffuse Region

High‐Resolution13CO and C18OJ= 1–0 Observations of NGC 1068: Molecular Gas Properties and a High C18O/13CO Intensity Ratio

1997 ◽  
Vol 477 (1) ◽  
pp. 518-518 ◽  
Author(s):  
Padeli P. Papadopoulos ◽  
E. R. Seaquist ◽  
N. Z. Scoville
Keyword(s):  
Intensity Ratio ◽  
Molecular Gas ◽  
Ngc 1068 ◽  
Gas Properties

The State of the Molecular Gas in a Luminous Starburst/Seyfert 2 Galaxy: NGC 1068 Revisited

1999 ◽  
Vol 516 (1) ◽  
pp. 114-126 ◽  
Author(s):  
Padeli P. Papadopoulos ◽  
E. R. Seaquist
Keyword(s):  
The State ◽  
Molecular Gas ◽  
Ngc 1068

scholarly journals Molecular Gas Distribution in Barred and Nonbarred Galaxies along the Hubble Sequence

2008 ◽  
Vol 178 (2) ◽  
pp. 225-246 ◽  
Author(s):  
S. Komugi ◽  
Y. Sofue ◽  
K. Kohno ◽  
H. Nakanishi ◽  
S. Onodera ◽  
...  
Keyword(s):  
Molecular Gas ◽  
Gas Distribution ◽  
Hubble Sequence

Class I Methanol Maser Emission in NGC 4945

2017 ◽  
Vol 13 (S336) ◽  
pp. 105-108
Author(s):  
Tiege P. McCarthy ◽  
Simon P. Ellingsen ◽  
Xi Chen ◽  
Shari L. Breen ◽  
Maxim A. Voronkov ◽  
...  
Keyword(s):  
Large Scale ◽  
Class I ◽  
Molecular Gas ◽  
Low Velocity ◽  
Extragalactic Source ◽  
Maser Emission ◽  
Methanol Maser ◽  
Methanol Masers

AbstractWe have detected maser emission from the 36.2 GHz (4−1 → 30E) methanol transition towards NGC 4945. This emission has been observed in two separate epochs and is approximately five orders of magnitude more luminous than typical emission from this transition within our Galaxy. NGC 4945 is only the fourth extragalactic source observed hosting class I methanol maser emission. Extragalactic class I methanol masers do not appear to be simply highly-luminous variants of their galactic counterparts and instead appear to trace large-scale regions where low-velocity shocks are present in molecular gas.

scholarly journals WISDOM project – VII. Molecular gas measurement of the supermassive black hole mass in the elliptical galaxy NGC 7052

2021 ◽  
Vol 503 (4) ◽  
pp. 5984-5996
Author(s):  
Mark D Smith ◽  
Martin Bureau ◽  
Timothy A Davis ◽  
Michele Cappellari ◽  
Lijie Liu ◽  
...  
Keyword(s):  
Black Hole ◽  
Hubble Space Telescope ◽  
Elliptical Galaxy ◽  
Continuum Emission ◽  
Molecular Gas ◽  
Supermassive Black Hole ◽  
Gas Kinematics ◽  
Long Baseline ◽  
Gas Measurement ◽  
Strong Gradient

ABSTRACT Supermassive black hole (SMBH) masses can be measured by resolving the dynamical influences of the SMBHs on tracers of the central potentials. Modern long-baseline interferometers have enabled the use of molecular gas as such a tracer. We present here Atacama Large Millimeter/submillimeter Array observations of the elliptical galaxy NGC 7052 at 0${^{\prime\prime}_{.}}$11 ($37\,$pc) resolution in the 12CO(2-1) line and $1.3\,$ mm continuum emission. This resolution is sufficient to resolve the region in which the potential is dominated by the SMBH. We forward model these observations, using a multi-Gaussian expansion of a Hubble Space Telescope F814W image and a spatially constant mass-to-light ratio to model the stellar mass distribution. We infer an SMBH mass of $2.5\pm 0.3\times 10^{9}\, \mathrm{M_\odot }$ and a stellar I-band mass-to-light ratio of $4.6\pm 0.2\, \mathrm{M_\odot /L_{\odot ,I}}$ (3σ confidence intervals). This SMBH mass is significantly larger than that derived using ionized gas kinematics, which however appears significantly more kinematically disturbed than the molecular gas. We also show that a central molecular gas deficit is likely to be the result of tidal disruption of molecular gas clouds due to the strong gradient in the central gravitational potential.

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