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SN 2023gfo: A Peculiar Type IIP Supernova with High Luminosity and Normal Plateau Duration
Riko Namba, Masayuki Yamanaka, Keiichi Maeda +9
We present near-infrared (NIR) and optical observations of the highly reddened Type IIP supernova (SN) 2023gfo in the nearby galaxy NGC 4995 ( Mpc), which reached…
Two years of shock interaction tracing three phases of evolution: the explosion of a Type IIn supernova, SN 2019vxm
Gitika Rameshan, Rishabh Singh Teja, D. K. Sahu +10
We present multi-wavelength photometric and optical spectroscopic observations of the long-lived interacting supernova SN 2019vxm, spanning more than two years after the explosion.…
SN 2024dy: Dust formation in a long-lived Type IIn supernova and constraints on the dust mass
Sota Goto, Masayuki Yamanaka, Koji S. Kawabata +10
Type~IIn supernovae (SNe) are a subclass of core-collapse SNe powered by interaction between the ejecta and the dense circumstellar material. Among them, long-lived Type~IIn events…
Tracking down the broadband polarimetric properties of PG 1553+113
Riccardo Middei, Svetlana G. Jorstad, Alan P. Marscher +78
We report on a nine-month monitoring campaign of the blazar PG 1553+113, relying on three observations carried out in 2025 with the Imaging X-ray Polarimetry Explorer (IXPE) and su…
The IXPE and multifrequency polarimetric view of the extreme blazars 1ES 1101-232 and RGB J0710+591
Fabrizio Tavecchio, Dawoon E. Kim, Gabriel Emery +53
Multiwavelength polarimetry is a powerful tool to probe magnetic field and flow geometries in the relativistic jets of blazars. In this respect, particularly interesting are the so…
Identifying the secondary jet in the RadioAstron image of OJ~287
Mauri J. Valtonen, Lankeswar Dey, Staszek Zola +26
The 136 year long optical light curve of OJ~287 is explained by a binary black hole model where the secondary is in a 12 year orbit around the primary. Impacts of the secondary on…
Unveiling blazar synchrotron emission: a multiwavelength polarimetric study of HSP and LSP populations
Sara Capecchiacci, Ioannis Liodakis, Riccardo Middei +96
Polarimetric properties of blazars allow us to put constraints on the acceleration mechanisms that fuel their powerful jets. By studying the multiwavelength polarimetric behaviour…
SN 2023xgo: Helium-rich Type Icn or Carbon-Flash Type Ibn supernova?
Anjasha Gangopadhyay, Jesper Sollerman, Konstantinos Tsalapatas +35
We present observations of SN~2023xgo, a transitional Type Ibn/Icn supernova, from to ~days relative to the -band peak. Early spectra show C~III emission rem…
A Two-Week Monitoring Campaign on Mrk 421
W. Peter Maksym, Ioannis Liodakis, M. Lynne Saade +153
X-ray polarization is a unique new probe of the particle acceleration in astrophysical jets made possible through the Imaging X-ray Polarimetry Explorer. Here we report on the firs…
SN 2021foa: the bridge between SN IIn and Ibn
Anjasha Gangopadhyay, Naveen Dukiya, Takashi J Moriya +26
We present the long-term photometric and spectroscopic analysis of a transitioning SN~IIn/Ibn from 10.8 d to 150.7 d post -band maximum. SN~2021foa shows prominent He {\sc i}…
X-ray and multiwavelength polarization of Mrk 501 from 2022 to 2023
Chien-Ting J. Chen, Ioannis Liodakis, Riccardo Middei +143
We present multiwavelength polarization measurements of the luminous blazar Mrk~501 over a 14-month period. The 2--8 keV X-ray polarization was measured with the Imaging X-ray Pola…
IXPE observation of PKS 2155-304 reveals the most highly polarized blazar
Pouya M. Kouch, Ioannis Liodakis, Riccardo Middei +133
We report the X-ray polarization properties of the high-synchrotron-peaked (HSP) blazar PKS 2155304 based on observations with the Imaging X-ray Polarimetry Explorer (IXPE). We…
Evidence of jet activity from the secondary black hole in the OJ287 binary system
Mauri J. Valtonen, Staszek Zola, Alok C. Gupta +29
We report the study of a huge optical intraday flare on November 12, 2021, at 2 am UT, in the blazar OJ287. In the binary black hole model it is associated with an impact of the se…
Unravelling the asphericities in the explosion and multi-faceted circumstellar matter of SN 2023ixf
Avinash Singh, R. S. Teja, T. J. Moriya +33
We present a detailed investigation of photometric, spectroscopic, and polarimetric observations of the Type II SN 2023ixf. Earlier studies have provided compelling evidence for a…
Intermediate-luminosity Type IIP SN 2021gmj: a low-energy explosion with signatures of circumstellar material
Yuta Murai, Masaomi Tanaka, Miho Kawabata +28
We present photometric, spectroscopic and polarimetric observations of the intermediate-luminosity Type IIP supernova (SN) 2021gmj from 1 to 386 days after the explosion. The peak…
Detection of X-ray Polarization from the Blazar 1ES 1959+650 with the Imaging X-ray Polarimetry Explorer
Manel Errando, Ioannis Liodakis, Alan P. Marscher +142
Observations of linear polarization in the 2-8 keV energy range with the Imaging X-ray Polarimetry Explorer (IXPE) explore the magnetic field geometry and dynamics of the regions g…
Insights into the broad-band emission of the TeV blazar Mrk 501 during the first X-ray polarization measurements
S. Abe, J. Abhir, V. A. Acciari +260
We present the first multi-wavelength study of Mrk 501 including very-high-energy (VHE) gamma-ray observations simultaneous to X-ray polarization measurements from the Imaging X-ra…
Quasi-simultaneous Optical Flux and Polarization Variability of the Binary Super Massive Black Hole Blazar OJ 287 from 2015 to 2023: Detection of an Anticorrelation in Flux and Polarization Variability
Alok C. Gupta, Pankaj Kushwaha, Mauri J. Valtonen +25
We study the optical flux and polarization variability of the binary black hole blazar OJ 287 using quasi-simultaneous observations from 2015 to 2023 carried out using telescopes i…
Observations of Low and Intermediate Spectral Peak Blazars with the Imaging X-ray Polarimetry Explorer
Herman L. Marshall, Ioannis Liodakis, Alan P. Marscher +145
We present X-ray polarimetry observations from the Imaging X-ray Polarimetry Explorer (IXPE) of three low spectral peak and one intermediate spectral peak blazars, namely 3C 273, 3…
Magnetic Field Properties inside the Jet of Mrk 421: Multiwavelength Polarimetry Including the Imaging X-ray Polarimetry Explorer
Dawoon E. Kim, Laura Di Gesu, Ioannis Liodakis +133
We conducted a polarimetry campaign from radio to X-ray wavelengths of the high-synchrotron-peak (HSP) blazar Mrk 421, including Imaging X-ray Polarimetry Explorer (IXPE) measureme…
Gamma rays from a reverse shock with turbulent magnetic fields in GRB 180720B
Makoto Arimoto, Katsuaki Asano, Koji S. Kawabata +14
Gamma-ray bursts (GRBs) are the most electromagnetically luminous cosmic explosions. They are powered by collimated streams of plasma (jets) ejected by a newborn stellar-mass black…
Bridging between type IIb and Ib supernovae: SN IIb 2022crv with a very thin Hydrogen envelope
Anjasha Gangopadhyay, Keiichi Maeda, Avinash Singh +26
We present optical, near-infrared, and radio observations of supernova (SN) SN~IIb 2022crv. We show that it retained a very thin H envelope and transitioned from a SN~IIb to a SN~I…
SN 2018gj: A Short-plateau Type II Supernova with Persistent Blue-shifted H-alpha Emission
Rishabh Singh Teja, Avinash Singh, D. K. Sahu +7
We present an extensive, panchromatic photometric (UV, Optical, and NIR) and low-resolution optical spectroscopic coverage of a Type IIP supernova SN 2018gj that occurred on the ou…
Far-Ultraviolet to Near-Infrared Observations of SN 2023ixf: A high energy explosion engulfed in complex circumstellar material
Rishabh Singh Teja, Avinash Singh, Judhajeet Basu +13
We present early-phase panchromatic photometric and spectroscopic coverage spanning far-ultraviolet (FUV) to the near-infrared (NIR) regime of the nearest hydrogen-rich core-collap…