C. V. Rodrigues

S 111 and the polarization of the B[e] supergiants in the Magellanic Clouds

We have obtained linear polarization measurements of the Large Magellanic Cloud B(e) supergiant S 111 using optical imaging polarimetry. The intrinsic polarization found is consistent with the presence of an axisymmetric circumstellar envelope. We have additionally estimated the electron density for S 111 using data from the literature and revisited the correlation between polarization and envelope parameters of the B(e) supergiant stars using more recent IR calibration color data. The data suggest that the polarization can be indeed explained by electron scattering. We have used Monte Carlo codes to model the continuum polarization of the Magellanic B(e) supergiants. The results indicate that the electron density distribution in their envelopes is closer to a homogeneous distribution rather than an r 2 dependence. At the same time, the data are best tted by a spherical distribution with density contrast than a cylindrical distribution. The data and the model results support the idea of the presence of an equatorial disk and of the two-component wind model for the envelopes of the B(e) supergiants. Spectropolarimetry would help further our knowledge of these envelopes.

Optical polarimetry and infrared photometry of two AM Her binaries: 1RXS J161008.0+035222 and 1RXS J231603.9−052713

We present the first optical circular and linear polarizatio n measurements of two polar candidates from ROSAT: 1RXS J161008.0+035222 and 1RXS J231603.9 052713. We also present H band near-infrared photometry of the last object. The presence of strong circular polarization confirms them as AM Her systems. 1RXS J231603.9 052713 was observed in two different brightness states. The orbital phase dependence of the flux and polarization of 1RXS J161008.0+035222 is reasonably fitted with a simple mod el in which the binary is observed at a small inclination and the magnetic field axis is al most parallel to the white-dwarf rotation axis resulting in the accretion column axis being s een from top during the whole orbital revolution. An alternative geometry with intermediate inclination can fit the observed flux and circular polarization. However, in this case, the mo del produces a linear polarization peak which is not corroborated by the data. The estimated magnetic field is in the 10 to 20 MG range. The circular polarization of 1RXS J231603.9 052713 is complex and highly variable. The light-curves of that object have been fitted using a model which includes the white-dwarf, a heated secondary and a point-like accretion region. The secondary emission contributes significantly even in optical wavelengths. This model also repr oduces the main features of the optical polarization of 1RXS J231603.9 052713. We estimate the main parameters of the binary, of the accretion region and the distance to the syste m. An improved description of this system should include an extended and inhomogeneous accreting region as well as non-radial accretion.

Optical polarimetric monitoring of the type II-plateau SN 2005af

Aims. Core-collapse supernovae may show significant polarization that implies non-spherically symmetric explosions. We observed the type II-plateau SN 2005af using optical polarimetry in order to verify whether any asphericity is present in the supernova temporal evolution. Methods. We used the IAGPOL imaging polarimeter to obtain optical linear polarization measurements in

Stokes imaging of AM Her systems using 3D inhomogeneous models – I. Description of the code and an application to V834 Cen

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Stokes imaging of AM Her systems using 3D inhomogeneous models – II. Modelling X-ray and optical data of CP Tucanae

(five epochs) and

Polarimetry of the binary PDS 144

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Magnetic field dispersion in the neighbourhood of Bok Globules

(one epoch) broadbands. Interstellar polarization was estimated from the field stars in the CCD frames. The optical polarimetric monitoring began around one month after the explosion and lasted ~30 days, between the plateau and the early nebular phase. Results. The weighted mean observed polarization in

SPARC4 A simultaneous polarimeter and rapid camera in 4 bands

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The magnetic field structure of the Small Magellanic Cloud

band was [ 1.89 ± 0.03] % at position angle (PA) 54

Search for an Infrared Counterpart of IGR J16358‐4756

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