А.М. Sobolev (Ural Federal University, Ekaterinburg, Russia)
S. Deguchi, W.D. Watson, D.M. Cragg, A.B. Ostrovskii, M.A. Voronkov, E.C. Sutton,
V.S. Strelnitskii, M. Gray, et al.
Hong Kong, 2011
Basics of Numerical Modelling of Molecular
Masers
Microwave I=I0 exp(-)
Amplification by if <0 matter
Stimulated amplifies background
Emission of instead of obscuring it
Radiation Maser effect is realized due to the pumping mechanism which reflects the balance between population transfer processes (radiative, collisional and chemical)
Why do we need to study masers?-------------------------------------------------------------
+ Sensitive tracers of specific objects
+ Tool to study kinematics (arranged and chaotic)
+ Tool to measure physical parameters
+ Tool to measure magnetic fields
+ Tool for direct measurement of distance
+ Tool to study structure of the Galaxy, etc.
Why do we need to study masers?-------------------------------------------------------------
+ Sensitive tracers of specific objects
+ Tool to study kinematics (arranged and chaotic)
+ Tool to measure physical parameters
+ Tool to measure magnetic fields
+ Tool for direct measurement of distance
+ Tool to study structure of the Galaxy, etc.
+ Unique phenomenon which is interesting by itself
Why do we need models?-------------------------------------------------------------
+ Find likely / optimum conditions
+ Reveal source gist: entities or correlations?
+ Understand spectra and maps:
(1) generic sources
(2) individual objects
+ Understand variability
+ Predict likely new masers
+ Reveal detailed pumping schemes
+ Resolve propagation problems
Model construction requires INPUT
elaboration of basic description which allows computation:
-definition of parameter space -basic relations.
OSO 20m CS(2-1)OSO 20m CS(2-1)Spitzer 3.6 uSpitzer 3.6 u
2m Faulkes telescope 2m Faulkes telescope optical imageoptical image
RHCP- - LHCP
relevant molecular spectroscopy and collisional rate coefficients importance of spectroscopy Sobolev&Deguchi (1994a)
relevant molecular spectroscopy and collisional rate coefficients importance of spectroscopy Sobolev&Deguchi (1994a)
relevant molecular spectroscopy and collisional rate coefficients importance of collisional coefficients
Dinah CraggDinah Cragg
conditions in and around
masing region
internal conditions
conditions in and around
masing region
internal conditions
conditions in and around
masing region
internal conditions
conditions in and around
masing region
external conditions
conditions in and around
masing region
external conditions
Dependence of maser line ratios on the pumping dust composition Ostrovskii & Sobolev (2002)
conditions in and around
masing region
external conditions
geometry and size of the masing region
G23.6576-0.127 S Per Bartkiewicz et al. (2005) Asaki et al. (2011)
colour -18.3 μm white cont.- 15 GHz grey cont. - L′
colour - 11.7 μm white cont. - K-band grey cont. - 8.5 GHz
G35.20-0.74 jet at different wavelengths (de Buizer et al. 2006)
zoom in on the centre colour - 11.7 μm white cont. - L′ black – 8.5 GHz * - OH masers x – H2O masers+ - CH3OH masers
BIMA spectra of methanol maser candidates in W3(OH) Sutton, Sobolev et al. (2001)
SuttonSutton
relevant molecular spectroscopy and collisional rate coefficients importance of spectroscopy Sobolev&Deguchi (1994a)
25 GHz masersin ОМС-1(Sobolev, Wallin & Watson 1998)
WatsonWatson
MentenMenten
propagation of maser radiation
So, we have considered INPUT
of the molecular maser numerical modeling
This description is not full. Mainly because we did not consider polarization and
related phenomena
Further we will consider OUTPUT
of the molecular maser numerical modeling
This description is also not full. We will be happy to hear
suggestions on what else is expected from the models!
Images and evolution for 25 GHz maser clusters
in model (Sobolev, Watson & Okorokov 2003)
WatsonWatson
MentenMenten
propagation of maser radiation
Time dependence of fluxes of 25 GHz maser spots and spectra in Model (Sobolev, Watson & Okorokov 2003)
Analysis of the images shows that the maser spots formed in the turbulent medium have fine structure and the brightest spots have small sizes (Sobolev, Watson & Okorokov 2003)
WatsonWatson
propagation of maser radiation
Change of the image with the viewing angle (Sobolev,Sutton,Watson,Ostrovskii & Shelemei 2008)
ShelemeiShelemei
OstrovskiiOstrovskii
One of the basic outputs is exploration of parameter space
Models of individual sources based on multi-transitional data on maser emission can be
found in Cragg et al. (2001, 2004), Sutton et al.(2001)Cragg et al. (2001, 2004), Sutton et al.(2001)
One of the basic outputs is exploration of parameter space
Model of generic (common) source based on extensive surveys of the 6, 23 & 107 GHz CH3OH
maser emission (Cragg et al., 2004)(Cragg et al., 2004)
Analysis of the pumping mechanismProcesses which control population numbers
1) Radiative Processes responsible for interaction with radiation field (i.e., emission and absorption of photons)
2) Collisional Processes responsible for interaction with particles of substance (acceleration of other particles)
3) Chemical Processes responsible for appearance/disappearance of particles in particular quantum states (chemical reactions, injection of particles, etc.)
Strelnitski
Analysis of the pumping mechanismSobolev & Deguchi (1994b)
Analysis of CH3OH maser pumping in W3(OH)
Sutton et al.(2001)
Predictions: list of maser candidates
class I CH3OH maser pumping (see poster) (Sobolev, Ostrovskii, Voronkov etal., 2005)(Sobolev, Ostrovskii, Voronkov etal., 2005)
Log TbLog Tb
Log densityLog density
Beaming=20, Tk= 50 K, Beaming=20, Tk= 50 K, log(Nm/dV)=10log(Nm/dV)=10
4 regimes distinguished by 4 regimes distinguished by the set of transitions displaying the set of transitions displaying the highest brightness temperature:the highest brightness temperature:
- JJ-1-1-(J-1)-(J-1)00E series: 4E series: 4-1-1-3-300E at 36.1, 5E at 36.1, 5-1-1-4-400E at E at
84.5 GHz , etc. (SgrB2, G1.6-0.025) 84.5 GHz , etc. (SgrB2, G1.6-0.025)
- JJ00-(J-1)-(J-1)11A+ series: 7A+ series: 700-6-611A+ at 44.1, 8A+ at 44.1, 800-7-711A+ A+
at 95.2 GHz, etc. (DR21W, NGC2264, OMC-2)at 95.2 GHz, etc. (DR21W, NGC2264, OMC-2)
- JJ22-J-J11E series at about 25 GHz: OMC-1E series at about 25 GHz: OMC-1
-JJ-2-2-(J-1)-(J-1)-1-1E series: 9E series: 9-2-2-8-8-1-1E at 9.9 & 11E at 9.9 & 11-2-2-10-10-1-1E E
line at 104.3 GHz (G343.12-0.06, W33A) line at 104.3 GHz (G343.12-0.06, W33A) VoronkovVoronkov
Implementation of the modeling for future research with the new facilities
Lists of maser candidate transitions for SMA (some of them are detected already) and ALMA ranges (to be published soon)
It is shown that changes of the CH3OH maser images in the turbulent model are quite slow and do not prevent measurement of the distances by trigonometric parallax method using data on the 12 GHz methanol masers (Sobolev et al. 2008)
Brightest maser spots have small sizes which fit demand of the space vlbi
THANKS A LOT!