zeeman
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Fits a single pixel of Stokes I and Stokes V cubes for the B field and draws a summary plot.
Usage:
tt.zeeman(filename, Icube, Vcube, Vrms=None, trials=1000, Z=None,
restfreq=None, xrange='', xplotrange=[0, 0], plotfile='',
showStokesV=False, debug=False, blc=None, trc=None,
overwrite=False, stokes='V')
Inputs:
- filename: the ASCII file containing the I and V spectra. If it does not exist, and the cubes exist, then it will run ispecs to generate it.
- Icube: the name of the Stokes I cube used to extract the spectrum (You don't need the cube to be on disk, only need to give the name.)
- Vcube: the name of the Stokes V cube used to extract the spectrum (You don't need the cube to be on disk, only need to give the name.)
- Vrms: the rms intensity to use for the Stokes V spectrum
- trials: if greater than 1, then compute uncertainties in the fit parameters with a Monte Carlo method
- Z: if specified along w/restfreq, then compute B_los (from 2b*d_nu/Z)
- restfreq: if specified, then convert d_nu from units in the file to Hz; if Z is not specified, print Z*B_los (it can be string with units, or floating point value in Hz or GHz)
- xrange: e.g. '17~23' (in the current units)
- blc, trc: only used if filename does not exist (i.e. to generate it with tt.ispec)
- overwrite: if True, generate new ASCII file (only used if cubes exist)
- stokes: only used to label the Vcube spectrum in the plot (e.g. change to 'Q' if you feed a Q cube to Vcube parameter)
Examples:
CASA <6>: tt.zeeman('test.370.340.txt','G06.05_july31.ms.contsub.ch3oh.spw0_I.image','G06.05_july31_X5de.ms_StokesI_V.image',blc=[370,340])
Running tt.ispecs to generate a new ASCII file.
Results left in test.370.340.txt
Using Vrms = 0.00534025203855
Plot left in test.370.340.txt.png
a = 0.00151408 +- 2.17924e-05
b = -0.000582965 +- 3.82987e-05
Out[6]
(0.0015140766121552953,
2.1792429208692971e-05,
-0.00058296533147814329,
3.8298669040193728e-05)
CASA <7>: tt.zeeman('test.370.340.txt','G06.05_july31.ms.contsub.ch3oh.spw0_I.image','G06.05_july31_X5de.ms_StokesI_V.image',blc=[370,340])
Using existing ASCII file.
Set overwrite=True to generate a new one.
Using Vrms = 0.00534025203855
Plot left in test.370.340.txt.png
a = 0.00151161 +- 2.11203e-05
b = -0.000583493 +- 3.6178e-05
Out[7]:
(0.0015116128658256701,
2.1120288236439519e-05,
-0.00058349290302604079,
3.6178009644488677e-05)
CASA <8>: tt.zeeman('test.370.340.txt','G06.05_july31.ms.contsub.ch3oh.spw0_I.image','G06.05_july31_X5de.ms_StokesI_V.image',blc=[370,340],overwrite=True)
Running tt.ispecs to generate a new ASCII file.
Results left in test.370.340.txt
Using Vrms = 0.00534025203855
Plot left in test.370.340.txt.png
a = 0.00151129 +- 2.02815e-05
b = -0.000581035 +- 3.85263e-05
Out[8]:
(0.0015112891523722089,
2.0281539437892505e-05,
-0.00058103474858294674,
3.8526260063765163e-05)
--
ToddHunter - 2015-08-03