| Name: | Athira M Bharathan |
| Affiliation: | CHRIST (Deemed to be University) |
| Conference ID : | ASI2024_1013 |
| Title : | Detection of X-ray polarization in the high synchrotron peaked blazar 1ES 1959+650 |
| Authors : | Athira M. Bharathan, 1,
C. S. Stalin, 2,
Rwitika Chatterjee, 3
S. Sahayanathan, 4
Indrani Pal, 2
Blesson Mathew, 1
Vivek K. Agrawal 3 |
| Authors Affiliation: | (1 )Department of Physics, CHRIST (Deemed to be University), Bangalore, India
(2) Indian Institute of Astrophysics, Block II, Koramangala, Bangalore 560 034 India
(3) Space Astronomy Group, ISITE Campus, U. R. Rao Satellite Centre, Bangalore 560 037, India
(4) Astrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai-400085, India
and Homi Bhabha National Institute, Mumbai-400094, India |
| Mode of Presentation: | Poster |
| Abstract Category : | High Energy Phenomena, Fundamental Physics and Astronomy |
| Abstract : | We report the first time measurement of X-ray polarization in the 2−8 keV band from the high
synchrotron peaked (HSP) blazar 1ES 1959+650. The low energy hump in the broadband spectral
energy distribution (SED) of blazars in the logν versus νF ν plane is believed to be due to the
synchrotron emission process from relativistic particles in their jets. In HSP blazars, the observed
X-ray emission lies in the high energy tail of the synchrotron part of the SED, and X-ray polarization
measurements can constrain the processes by which particles are accelerated in their jets. We present here our results on the X-ray polarization characteristics of 1ES 1959+650 using observations carried out by the Imaging X-ray Polarimetry Explorer (IXPE). IXPE observed this source for four epochs between May 2022 and August 2023, with observation time ranging from about 50 to 300 ksec. Of the four epochs of observations, we detected polarization on two epochs, significantly larger than the minimum detectable polarization values. From model-independent analysis during the observations on 28 October 2022, in the 2−8 keV band, we found the degree of polarization of Π X = 9.0 ± 1.6 % and an electric vector position angle of ψ X = 53 ± 5 deg. Similarly, from the observations on 14 August 2023, we found Π X and ψ X values as 12.5 ± 0.7 % and 20 ± 2 deg respectively in the 2−8 keV band. These values obtained from model-independent analysis are also in agreement with the values obtained from spectro-polarimetric analysis of the I,Q, and U spectra in the 2−8 keV range. The measured X-ray polarization is larger than that known in the optical that ranges between 2.5−9% during the period 2008 to 2018. This result can be inferred as the shock acceleration of the particles in the jet of 1ES 1959+650. |
