2016/10/15 by R. V. Yudin, S. Potter, S. B. Potter +1
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Binary number #Galaxy #Gamma-ray bursts and supernovae #Optics #Orbital inclination #Physics #Polarimetry #Polarization (electrochemistry) #Position angle #Scattering #Stars #Wavelength #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.1093/mnras/stw2676
7 pages, 4 figures, Accepted for publication in MNRAS on 2016 October 14
arxiv created 2016/10/15 · openalex publication_date 2016/10/17 · openalex created_date 2016/10/28 · arxiv updated 2016/12/07 · openalex updated_date 2026/08/05
We present the results of UBVRI polarimetry of the TeV γ-ray binary HESS J0632+057 obtained on 2015 March 24 (JD 245 7106) and 2015 December 12 (JD 245 7369). The detected polarization values of HESS J0632+057, just after periastron passage (March 24), are higher than all previously published values (pV ∼ 4.2 per cent), and the position angle (Θobs ∼ 171°–172°) is also different by ∼6°–10° from previously published values. The data obtained just before the subsequent periastron passage (December 12) show a statistically lower polarization in all photometric bands (pV ∼3.9 per cent) and a different position angle Θobs ∼ 167°–168°. From observations of a nearby field star, the interstellar component of the measured polarization was estimated as |p_\rm isV| ∼ 0.65 per cent and Θis ∼ 153°. This estimate was used with the previous ‘V’-band estimation by the ‘field-stars method’ (|p_\rm isV| ∼ 2 per cent and Θis ∼ 165°) of Yudin to identify the wavelength dependence of the intrinsic polarization in HESS J0632+057. It was found that after subtraction of the interstellar component (for both pis estimates), the wavelength dependence of the intrinsic polarization in HESS J0632+057 is essentially flat. We propose that the formation of an additional source of polarization or some perturbation of circumstellar material at this orbital phase can explain the changes in the level of polarization in HESS J0632+057 close to periastron passage.