Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Articles Article Faculty Publications -Articles Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Simultaneous X-Ray and Optical Polarization Observations of the Blazar Mrk 421 Description An account of the resource We present near-simultaneous X-ray and optical polarization measurements in the high synchrotron peaked (HSP) blazar Mrk 421. The X-ray polarimetric observations were carried out using Imaging X-ray Polarimetry Explorer (IXPE) on 2023 December 6. During IXPE observations, we also carried out optical polarimetric observations using 104 cm Sampurnanand telescope at Nainital and multiband optical imaging observations using 2 m Himalayan Chandra Telescope at Hanle. From model-independent analysis of IXPE data, we detected X-ray polarization with degree of polarization (?X) of 8.5% 0.5% and an electric vector position angle (?X) of 10.6 1.7 in the 2?8 keV band. From optical polarimetry on 2023 December 6, in B, V, and R bands, we found values of ?B = 4.27% 0.32%, ?V = 3.57% 0.31%, and ?R = 3.13% 0.25%. The value of ?B is greater than that observed at longer optical wavelengths, with the degree of polarization suggesting an energy-dependent trend, gradually decreasing from higher to lower energies. This is consistent with that seen in other HSP blazars and favors a stratified emission region encompassing a shock front. The emission happening in the vicinity of the shock front will be more polarized due to the ordered magnetic field resulting from shock compression. The X-ray emission, involving high-energy electrons, originates closer to the shock front than the optical emission. The difference in the spatial extension could plausibly account for the observed variation in polarization between X-ray and optical wavelengths. This hypothesis is further supported by the broadband spectral energy distribution modeling of the X-ray and optical data. 2024. The Author(s). Published by the American Astronomical Society. Creator An entity primarily responsible for making the resource Bharathan A.M.; Stalin C.S.; Sahayanathan S.; Wani K.; Mandal A.K.; Chatterjee R.; Joshi S.; Pandey J.C.; Mathew B.; Agrawal V.K. Source A related resource from which the described resource is derived Astrophysical Journal, Vol-975, No. 2 Publisher An entity responsible for making the resource available Institute of Physics Date A point or period of time associated with an event in the lifecycle of the resource 2024-01-01 Identifier An unambiguous reference to the resource within a given context <a href="https://doi.org/10.3847/1538-4357/ad8081" target="_blank" rel="noreferrer noopener">https://doi.org/10.3847/1538-4357/ad8081</a> <br /><br /><a href="https://www.scopus.com/inward/record.uri?eid=2-s2.0-85209195241&amp;doi=10.3847%2F1538-4357%2Fad8081&amp;partnerID=40&amp;md5=4947d2ebe3a66928b5fec7898d1ea302" target="_blank" rel="noreferrer noopener">https://www.scopus.com/inward/record.uri?eid=2-s2.0-85209195241&amp;doi=10.3847%2f1538-4357%2fad8081&amp;partnerID=40&amp;md5=4947d2ebe3a66928b5fec7898d1ea302</a> Rights Information about rights held in and over the resource All Open Access; Gold Open Access; Green Open Access Relation A related resource ISSN: 0004637X Format The file format, physical medium, or dimensions of the resource Online Language A language of the resource English Type The nature or genre of the resource Article Coverage The spatial or temporal topic of the resource, the spatial applicability of the resource, or the jurisdiction under which the resource is relevant Bharathan A.M., Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore, India; Stalin C.S., Indian Institute of Astrophysics, Block II, Koramangala, Bangalore, 560 034, India; Sahayanathan S., Astrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai, 400085, India, Homi Bhabha National Institute, Mumbai, 400094, India; Wani K., Aryabhatta Research Institute for Observational Sciences, Manora Peak, Nainital, India, School of Physical Sciences, SRTM University, Nanded, 431 606, India; Mandal A.K., Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul, 151-742, South Korea; Chatterjee R., Space Astronomy Group, U. R. Rao Satellite Centre, ISITE Campus, Bangalore, 560 037, India; Joshi S., Aryabhatta Research Institute for Observational Sciences, Manora Peak, Nainital, India; Pandey J.C., Aryabhatta Research Institute for Observational Sciences, Manora Peak, Nainital, India; Mathew B., Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore, India; Agrawal V.K., Space Astronomy Group, U. R. Rao Satellite Centre, ISITE Campus, Bangalore, 560 037, India