- ID:
- ivo://CDS.VizieR/J/A+A/591/A92
- Title:
- BVR polarimetry of HD 48099
- Short Name:
- J/A+A/591/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the structure of the O-type binary system HD 48099 by measuring linear polarization that arises due to light scattering process. High-precision polarimetry provides independent estimates of the orbital parameters and gives important information on the properties of the system. Linear polarization measurements of HD 48099 in the B, V and R passbands with the high-precision Dipol-2 polarimeter have been carried out. The data have been obtained with the 60cm KVA (Observatory Roque de los Muchachos, La Palma, Spain) and T60 (Haleakala, Hawaii, USA) remotely controlled telescopes during 31 observing nights.Polarimetry in the optical wavelengths has been complemented by observations in the X-rays with the SWIFT space observatory. Optical polarimetry revealed small intrinsic polarization in HD 48099 with 0.1% peak to peak variation over the orbital period of 3.08d. The variability pattern is typical for binary systems, showing strong second harmonic of the orbital period. We apply our model code for the electron scattering in the circumstellar matter to put constraints on the system geometry. A good model fit is obtained for scattering of light on a cloud produced by the colliding stellar winds. The geometry of the cloud, with a broad distribution of scattering particles away from the orbital plane, helps in constraining the (low) orbital inclination. We derive from the polarization data the inclination i=17{deg}+/-2{deg} and the longitude of the ascending node Omega=82{deg}+/-1{deg} of the binary orbit. The available X-ray data provide additional evidence for the existence of the colliding stellar winds in the system. Another possible source of the polarized light could be scattering from the stellar photospheres. The models with circumstellar envelopes, or matter confined to the orbital plane, do not provide good constraints on the low inclination, better than i<=27{deg}, as is already suggested by the absence of eclipses.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/575/A89
- Title:
- Center-to-limb polarization of FGK stars
- Short Name:
- J/A+A/575/A89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Scattering and absorption processes in stellar atmosphere act the center-to-limb variations of the intensity (CLVI) and the linear polarization (CLVP) of stellar radiation. There are several theoretical and observational studies of CLVI using different stellar models, however, most studies of CLVP have concentrated on the solar atmosphere and have not considered the CLVP in cooler non-gray stellar atmospheres at all. In this paper, we present a theoretical study of the CLV of the intensity and the linear polarization in continuum spectra of different spectral type stars. We solve the radiative transfer equations for polarized light iteratively assuming no magnetic field and considering a planeparallel model atmospheres and various opacities.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A87
- Title:
- Center-to-limb polarization of FGK stars
- Short Name:
- J/A+A/586/A87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the necessary parameters needed for the interpretation of the light curves of transiting exoplanets or eclipsing binary stars (as well as interferometric measurements of a star or microlensing events) is how the intensity and polarization of light changes from the center to the limb of a star. Scattering and absorption processes in the stellar atmosphere affect both the center-to-limb variation of intensity (CLVI) and polarization (CLVP). In this paper, we present a study of the CLVI and CLVP in continuum spectra, taking into consideration the different contributions of scattering and absorption opacity for a variety of spectral type stars with spherical atmospheres. We solve the radiative transfer equation for polarized light in the presence of a continuum scattering, taking into consideration the spherical model of a stellar atmosphere. To cross-check our results, we developed two independent codes that are based on Feautrier and short characteristics methods, respectively, We calculate the center-to-limb variation of intensity (CLVI) and polarization (CLVP) in continuum for the Phoenix grid of spherical stellar model atmospheres for a range of effective temperatures (4000-7000K), gravities (logg=1.0-5.5), and wavelengths (4000-7000{AA}). In addition, we present several tests of our codes and compare our calculations for the solar atmosphere with published photometric and polarimetric measurements. We also show that our two codes provide similar results in all considered cases.
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/1210
- Title:
- Characteristics of energetic pulsars
- Short Name:
- J/MNRAS/391/1210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we compare the characteristics of pulsars with a high spin-down energy loss rate (Edot) against those with a low Edot. We show that the differences in the total intensity pulse morphology between the two classes are in general rather subtle. A much more significant difference is the fractional polarization which is very high for high Edot pulsars and low for low Edot pulsars. The Edot at the transition is very similar to the death line predicted for curvature radiation. This suggests a possible link between high energy and radio emission in pulsars and could imply that gamma-ray efficiency is correlated with the degree of linear polarization in the radio band. As part of this study, we have discovered three previous unknown interpulse pulsars (and we detected one for the first time at 20cm). We also obtained rotation measures for 18 pulsars whose values had not previously been measured.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1262
- Title:
- Circular polarization images at 15GHz of AGN jets
- Short Name:
- J/AJ/131/1262
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report first-epoch circular polarization results for 133 active galactic nuclei in the MOJAVE (Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments) program to monitor the structure and polarization of a flux-limited sample of extragalactic radio jets with the VLBA at 15GHz. We found strong circular polarization (0.3%) in approximately 15% of our sample. The circular polarization was usually associated with jet cores; however, we did find a few strong jet components to be circularly polarized.
- ID:
- ivo://CDS.VizieR/J/other/ChJAA/6.237
- Title:
- Circular polarization in pulsars
- Short Name:
- J/other/ChJAA/6.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We update the systematic studies of circular polarization in integrated pulse profiles by Han et al. (1998MNRAS.300..373H). Data of circular polarization profiles are compiled. Sense reversals can occur in core or cone components, or near the intersection between components. The correlation between the sense of circular polarization and the sense of position angle variation for conal-double pulsars is confirmed with a much large database. Circular polarization of some pulsars has clear changes with frequency. Circular polarization of millisecond pulsars is marginally different from that of normal pulsars.
- ID:
- ivo://CDS.VizieR/J/other/Ap/47.305
- Title:
- Circular polarization of starlight
- Short Name:
- J/other/Ap/47.30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Of the 7500 stars cited in the Catalog of starlight polarization (Cat. <II/34>), those which satisfy the condition P<=0.3% and A_V_>=0.5mag are selected. It is presumed that the selected stars (n=216) have circularly polarized light.
- ID:
- ivo://CDS.VizieR/J/AZh/73/194
- Title:
- Circumstellar Disks of Ae/Be Herbig Stars
- Short Name:
- J/AZh/73/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The data of the photo-polarimetric activity of Ae/Be Herbig stars and the types of Ha profiles observed in their spectra was carried out using data from the literature. The analysis of the data supports the presence of a relationship between the type of Ha profile and the level of photo-polarimetric activity in young stars.
- ID:
- ivo://CDS.VizieR/J/A+A/503/827
- Title:
- 6cm and 11cm polarisation maps of SNR G65.2+5.7
- Short Name:
- J/A+A/503/827
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SNR G65.2+5.7 is one of few supernova remnants (SNRs) that have been optically detected. It is exceptionally bright in X-rays and the optical [O III]-line. Its low surface brightness and large diameter ensure that radio observations of SNR G65.2+5.7 are technically difficult and thus have hardly been completed. Many physical properties of this SNR, such as spectrum and polarization, can only be investigated by radio observations.
- ID:
- ivo://CDS.VizieR/J/A+A/482/783
- Title:
- 6cm and 11cm polarisation maps of SNR S147
- Short Name:
- J/A+A/482/783
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- S147 is a large faint shell-type supernova remnant (SNR) known for its remarkable spectral break at cm-wavelength, which is an important physical property to characterize SNR evolution. However, the spectral break is based on radio observations with limited precision. New sensitive observations at high frequencies are required for a detailed study of the spectral properties and the magnetic field structure of S147.
