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!