J/A+A/524/A99 Polarisation of S Per and VX Sgr in OH (Szymczak+, 2010)
Outburst OH maser activity in the envelopes of S Persei and VX Sagittarii.
Szymczak M., Wolak P., Gerard E., Richards A.M.S.
<Astron. Astrophys. 524, A99 (2010)>
=2010A&A...524A..99S 2010A&A...524A..99S
ADC_Keywords: Stars, supergiant ; Polarization
Keywords: masers - polarization - circumstellar matter - supergiants -
stars: individual (S Per, VX Sgr)
Abstract:
Two red supergiant star S Per and VX Sgr were observed in the OH 1612
and 1667MHz maser lines with the Nancay radio telescope at several
runs in 2002-2005 and 2002-2008, respectively. Both targets were
sampled at irregular intervals of 2-3 days up to 4 months. Time
series of OH spectra in the Stokes parameters I, Q, U and V are
presented. The spectra of the linearly polarized flux density,
p=sqrt{Q2+U2}, the degrees of circular polarization, mC=V/I
linear polarization, mL=p/I, and position angle,
χ=0.5xtan-1(U/Q), drived from the Stokes parameters are also
given. The degrees of polarization at 1667MHz show diverse behaviours
usually uncorrelated with the total flux, whereas those at 1612MHz are
commonly stable on time scales of 4-6yr. Several outbursts of the
1667MHz emission on time scales of 0.5-2yr were found in both targets.
The bursting features are highly polarized and show drifts in
velocity. Small changes of the degrees of polarization and smooth
variations of position angle of linear polarization during the bursts
were observed in S Per but they are more dramatic in VX Sgr.
Description:
Full-polarization OH 1612 and 1667MHz time-series of the red
supergiants S Per and VX Sgr are presented.
Objects:
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RA (2000) DE Designation(s)
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02 22 51.71 +58 35 11.4 S Per = IRAS 02192+5821
18 08 04.05 -22 13 26.6 VX Sgr = IRAS 18050-2213
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 262 17920 OH 1612MHz time series for S Per
table2.dat 262 18432 OH 1667MHz time series for S Per
table3.dat 262 37376 OH 1612MHz time series for VX Sgr
table4.dat 262 37376 OH 1667MHz time series for VX Sgr
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See also:
J/ApJ/640/982 : 43GHz SiO maser features around VX Sgr (Chen+, 2006)
Byte-by-byte Description of file: table1.dat table2.dat table3.dat table4.dat
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Bytes Format Units Label Explanations
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4- 5 I2 --- N Epoch number
9- 12 I4 d MJD Modified Julian Date of observation
15- 23 F9.4 yr Year Year of observation
26- 28 I3 --- Chan Number of spectral channel
33- 40 F8.4 km/s VLSR Local Standard of Rest velocity
47- 53 F7.3 Jy I Stokes I flux density
60- 64 F5.3 Jy e_I Error of Stokes I flux density
69- 75 F7.3 Jy Q Stokes Q flux density
82- 86 F5.3 Jy e_Q Error of Stokes Q flux density
91- 97 F7.3 Jy U Stokes U flux density
104-108 F5.3 Jy e_U Error of Stokes U flux density
113-119 F7.3 Jy V Stokes V flux density
126-130 F5.3 Jy e_V Error of Stokes V flux density
135-141 F7.3 Jy p Flux density of linear polarization
148-152 F5.3 Jy e_p Error of flux density of linear polarization
155-163 F9.3 % mL Degree of linear polarization
166-174 F9.3 % e_mL ? Error of degree of linear polarization
175 A1 --- n_mL [I] I for +Infinity
177-185 F9.3 % mC Degree of circular polarization
188-196 F9.3 % e_mC ? Error of degree of circular polarization
197 A1 --- n_mC [I] I for +Infinity
200-207 F8.3 deg chi Polarization angle (1)
210-218 F9.3 deg e_chi ?=- Error of polarization angle (1)
223-229 F7.3 Jy LHC Flux density of left hand circular polarization
236-240 F5.3 Jy e_LHC Error of LHC flux density
245-251 F7.3 Jy RHC Flux density of right hand circular polarization
258-262 F5.3 Jy e_RHC Error of RHC flux density
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Note (1): For spectral channels free of emission 'chi' cannot be determined,
so the values for 'chi' and 'e_chi' are random and senseless.
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Acknowledgements:
Marian Szymczak, msz(at)astro.uni.torun.pl
(End) Patricia Vannier [CDS] 25-Nov-2010