papers

Publications (81)

astro-ph.HE2022

The X-ray polarimetry view of the accreting pulsar Cen X-3

Sergey S. Tsygankov, Victor Doroshenko, Juri Poutanen +95

Cen X-3 is the first X-ray pulsar discovered 50 years ago. Radiation from such objects is expected to be highly polarized due to birefringence of plasma and vacuum associated with…

astro-ph.HE2024

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…

astro-ph.HE2022

Incremental Fermi Large Area Telescope Fourth Source Catalog

LAT collaboration, Soheila Abdollahi, Fabio Acero +137

We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi-LAT catalog of gamma-ray sources. Based on the first twelve years of science data in the energy…

astro-ph.HE2023

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…

astro-ph.HE2025

Super-Eddington Accretion Geometry: a Remarkable Stability of the Hidden Ultraluminous X-Ray Source Cygnus X-3

Romana Mikušincová, Alexandra Veledina, Fabio Muleri +112

We report on the average and orbital phase-resolved polarization of Cyg X-3 in the hard state during the 2023 Imaging X-ray Polarimetry Explorer (IXPE) observational campaign. We f…

astro-ph.HE2022

The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope -- Data Release 3

LAT collaboration, Marco Ajello, Luca Baldini +100

An incremental version of the fourth catalog of active galactic nuclei (AGNs) detected by the Fermi-Large Area Telescope is presented. This version (4LAC-DR3) derives from the thir…

astro-ph.HE2022

The X-ray Polarization View of Mrk~421 in an Average Flux State as Observed by the Imaging X-ray Polarimetry Explorer

Laura Di Gesu, Immacolata Donnarumma, Fabrizio Tavecchio +100

Particle acceleration mechanisms in supermassive black hole jets, such as shock acceleration, magnetic reconnection, and turbulence, are expected to have observable signatures in t…

astro-ph.HE2015

Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory

The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu +461

A measurement of the cosmic-ray spectrum for energies exceeding eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\…

astro-ph.IM2025

Mitigating Polarization Leakage in Gas Pixel Detectors through Hybrid Machine Learning and Analytic Event Reconstruction

Nicoló Cibrario, Michela Negro, Raffaella Bonino +18

Spatially resolved polarization measurements of extended X-ray sources are expanding our understanding of the emission mechanisms and magnetic field properties involved. Such measu…

astro-ph.HE2023

X-ray Polarization of the Eastern Lobe of SS 433

Philip Kaaret, Riccardo Ferrazzoli, Stefano Silvestri +103

How astrophysical systems translate the kinetic energy of bulk motion into the acceleration of particles to very high energies is a pressing question. SS 433 is a microquasar that…

astro-ph.HE2023

Discovery of strongly variable X-ray polarization in the neutron star low-mass X-ray binary transient XTE J1701462

Massimo Cocchi, Andrea Gnarini, Sergio Fabiani +105

After about 16 years since its first outburst, the transient neutron star low-mass X-ray binary XTE J1701462 turned on again in September 2022, allowing for the first study of i…

astro-ph.HE2024

Evidence for a shock-compressed magnetic field in the northwestern rim of Vela Jr. from X-ray polarimetry

Dmitry A. Prokhorov, Yi-Jung Yang, Riccardo Ferrazzoli +97

Synchrotron X-ray emission has been detected from nearly a dozen young supernova remnants (SNRs). X-rays of synchrotron origin exhibit linear polarization in a regular, non-randoml…

astro-ph.HE2023

Complex variations of X-ray polarization in the X-ray pulsar LS V +44 17/RX J0440.9+4431

Victor Doroshenko, Juri Poutanen, Jeremy Heyl +109

We report on Imaging X-ray polarimetry explorer (IXPE) observations of the Be-transient X-ray pulsar LS V +44 17/RX J0440.9+4431 made at two luminosity levels during the giant outb…

astro-ph.HE2022

X-ray polarization detection of Cassiopeia A with IXPE

Jacco Vink, Dmitry Prokhorov, Riccardo Ferrazzoli +92

We report on a detection of polarized 3-6 keV X-ray emission from the supernova remnant Cassiopeia A with the Imaging X-ray Polarimetry Explorer (IXPE). The overall pola…

astro-ph.HE2023

Polarized Blazar X-rays imply particle acceleration in shocks

Ioannis Liodakis, Alan P. Marscher, Iván Agudo +125

Most of the light from blazars, active galactic nuclei with jets of magnetized plasma that point nearly along the line of sight, is produced by high-energy particles, up to $\sim 1…

astro-ph.HE2022

Polarization properties of the weakly magnetized neutron star X-ray binary GS 1826-238 in the high soft state

Fiamma Capitanio, Sergio Fabiani, Andrea Gnarini +94

The launch of the Imaging X-ray Polarimetry Explorer (IXPE) on 2021 December 9 has opened a new window in X-ray astronomy. We report here the results of the first IXPE observation…

astro-ph.HE2023

X-ray polarimetry of the accreting pulsar GX 301-2

Valery F. Suleimanov, Sofia V. Forsblom, Sergey S. Tsygankov +102

The phase- and energy-resolved polarization measurements of accreting X-ray pulsars (XRPs) allow us to test different theoretical models of their emission, and they also provide an…

astro-ph.HE2024

Tracking the X-ray Polarization of the Black Hole Transient Swift J1727.8-1613 during a State Transition

Adam Ingram, Niek Bollemeijer, Alexandra Veledina +120

We report on an observational campaign on the bright black hole X-ray binary Swift J1727.81613 centered around five observations by the Imaging X-ray Polarimetry Explorer (IXPE)…

astro-ph.HE2023

The Third Fermi Large Area Telescope Catalog of Gamma-ray Pulsars

David A. Smith, Philippe Bruel, Colin J. Clark +156

We present 294 pulsars found in GeV data from the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. Another 33 millisecond pulsars (MSPs) discovered in deep radio…

astro-ph.HE2024

First detection of polarization in X-rays for PSR B0540-69 and its nebula

Fei Xie, Josephine Wong, Fabio La Monaca +100

We report on X-ray polarization measurements of the extra-galactic Crab-like PSR B0540-69 and its Pulsar Wind Nebula (PWN) in the Large Magellanic Cloud (LMC), using a ~850 ks Imag…

astro-ph.IM2021

The Instrument of the Imaging X-ray Polarimetry Explorer

Paolo Soffitta, Luca Baldini, Ronaldo Bellazzini +78

While X-ray Spectroscopy, Timing and Imaging have improved verymuch since 1962, when the first astronomical non-solar source was discovered, especially with the launch of Newton/X-…

astro-ph.HE2024

An IXPE-Led X-ray Spectro-Polarimetric Campaign on the Soft State of Cygnus X-1: X-ray Polarimetric Evidence for Strong Gravitational Lensing

James F. Steiner, Edward Nathan, Kun Hu +134

We present the first X-ray spectropolarimetric results for Cygnus X-1 in its soft state from a campaign of five IXPE observations conducted during 2023 May-June. Companion multiwav…

astro-ph.HE2022

Observations of 4U 1626-67 with the Imaging X-ray Polarimetry Explorer

Herman L. Marshall, Mason Ng, Daniele Rogantini +91

We present measurements of the polarization of X-rays in the 2-8 keV band from the pulsar in the ultracompact low mass X-ray binary 4U1626-67 using data from the Imaging X-ray Pola…

astro-ph.HE2024

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…

astro-ph.HE2023

The first X-ray polarimetric observation of the black hole binary LMC X-1

Jakub Podgorny, Lorenzo Marra, Fabio Muleri +108

We report on an X-ray polarimetric observation of the high-mass X-ray binary LMC X-1 in the high/soft state, obtained by the Imaging X-ray Polarimetry Explorer (IXPE) in October 20…

astro-ph.HE2023

The Polarized Cosmic Hand: IXPE Observations of PSR B1509-58/MSH 15-52

Roger W. Romani, Josephine Wong, Niccolo Di Lalla +99

We describe IXPE polarization observations of the Pulsar Wind Nebula (PWN) MSH15-52, the `Cosmic Hand'. We find X-ray polarization across the PWN, with B field vectors generally al…

astro-ph.HE2024

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…

astro-ph.HE2025

IXPE Observation of the Low-Synchrotron Peaked Blazar S4 0954+65 During An Optical-X-ray Flare

Pouya M. Kouch, Ioannis Liodakis, Francesco Fenu +134

The X-ray polarization observations made possible with the Imaging X-ray Polarimetry Explorer (IXPE) offer new ways of probing high-energy emission processes in astrophysical jets…

astro-ph.HE2023

Vela pulsar wind nebula x-rays are polarized to near the synchrotron limit

Fei Xie, Alessandro Di Marco, Fabio La Monaca +90

Pulsar wind nebulae are formed when outflows of relativistic electrons and positrons hit the surrounding supernova remnant or interstellar medium at a shock front. The Vela pulsar…

astro-ph.HE2024

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…

astro-ph.HE2024

X-Ray Polarimetry of the Dipping Accreting Neutron Star 4U 1624-49

M. Lynne Saade, Philip Kaaret, Andrea Gnarini +98

We present the first X-ray polarimetric study of the dipping accreting neutron star 4U 162449 with the Imaging X-ray Polarimetry Explorer (IXPE). We report a detection of polari…

astro-ph.HE2024

Highly Significant Detection of X-Ray Polarization from the Brightest Accreting Neutron Star Sco X-1

Fabio La Monaca, Alessandro Di Marco, Juri Poutanen +116

The Imaging X-ray Polarimetry Explorer (IXPE) measured with high significance the X-ray polarization of the brightest Z-source Scorpius X-1, resulting in the nominal 2-8 keV energy…

astro-ph.HE2023

X-Ray Polarized View on the Accretion Geometry in the X-Ray Binary Circinus X-1

John Rankin, Fabio La Monaca, Alessandro Di Marco +101

Cir X-1 is a neutron star X-ray binary characterized by strong variations in flux during its eccentric 16.6 days orbit. There are also strong variations in the spectral state…

astro-ph.HE2024

Discovery of a strong rotation of the X-ray polarization angle in the galactic burster GX 13+1

Anna Bobrikova, Sofia V. Forsblom, Alessandro Di Marco +106

Weakly magnetized neutron stars in X-ray binaries show complex phenomenology with several spectral components that can be associated with the accretion disk, boundary and/or spread…

astro-ph.HE2023

X-ray Polarization of the BL Lac Type Blazar 1ES 0229+200

Steven R. Ehlert, Ioannis Liodakis, Riccardo Middei +110

We present polarization measurements in the band from blazar 1ES 0229+200, the first extreme high synchrotron peaked source to be observed by the Imag…

astro-ph.HE2026

Magnetic-field Order in the Southwestern Rim of RCW 86 Constrained Using X-Ray Polarimetry

Stefano Silvestri, Dmitry Prokhorov, Jacco Vink +97

RCW 86 is a supernova remnant whose origin has recently been linked to an off-center explosion within a cavity created by its progenitor star. In the southwestern region, the forwa…

astro-ph.HE2024

Cygnus X-3 revealed as a Galactic ultraluminous X-ray source by IXPE

Alexandra Veledina, Fabio Muleri, Juri Poutanen +127

The accretion of matter by compact objects can be inhibited by radiation pressure if the luminosity exceeds the critical value, known as the Eddington limit. Discovery of ultralumi…

astro-ph.HE2022

Polarized x-rays from a magnetar

Roberto Taverna, Roberto Turolla, Fabio Muleri +93

We report on the first detection of linearly polarized x-ray emission from an ultra-magnetized neutron star with the Imaging X-ray Polarimetry Explorer (IXPE). The IXPE 35 observat…

astro-ph.HE2025

The enhanced X-ray Timing and Polarimetry mission -- eXTP for launch in 2030

Shuang-Nan Zhang, Andrea Santangelo, Yupeng Xu +155

In this paper we present the current status of the enhanced X-ray Timing and Polarimetry mission, which has been fully approved for launch in 2030. eXTP is a space science mission…

astro-ph.HE2025

High optical to X-ray polarization ratio reveals Compton scattering in BL Lacertae's jet

Ivan Agudo, Ioannis Liodakis, Jorge Otero-Santos +147

Blazars, supermassive black hole systems (SMBHs) with highly relativistic jets aligned with the line of sight, are the most powerful long-lived emitters of electromagnetic emission…

astro-ph.HE2022

X-ray Polarization Observations of BL Lacertae

Riccardo Middei, Ioannis Liodakis, Matteo Perri +143

Blazars are a class of jet-dominated active galactic nuclei with a typical double-humped spectral energy distribution. It is of common consensus the Synchrotron emission to be resp…

astro-ph.HE2015

An improved limit to the diffuse flux of ultra-high energy neutrinos from the Pierre Auger Observatory

The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu +462

Neutrinos in the cosmic ray flux with energies near 1 EeV and above are detectable with the Surface Detector array of the Pierre Auger Observatory. We report here on searches throu…

astro-ph.IM2022

A weighted analysis to improve the X-ray polarization sensitivity of IXPE

Alessandro Di Marco, Enrico Costa, Fabio Muleri +29

IXPE is a Small Explorer mission that was launched at the end of 2021 to measure the polarization of X-ray emission from tens of astronomical sources. Its focal plane detectors are…

astro-ph.HE2023

X-ray polarization evidence for a 200 years-old flare of Sgr A

Frédéric Marin, Eugene Churazov, Ildar Khabibullin +101

The center of the Milky Way Galaxy hosts a 4 million solar mass black hole (Sgr A) that is currently very quiescent with a luminosity many orders of magnitude below those…

astro-ph.HE2023

IXPE and multi-wavelength observations of blazar PG 1553+113 reveal an orphan optical polarization swing

Riccardo Middei, Matteo Perri, Simonetta Puccetti +119

The lower energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consen…

astro-ph.HE2024

Probing the polarized emission from SMC X-1: the brightest X-ray pulsar observed by IXPE

Sofia V. Forsblom, Sergey S. Tsygankov, Juri Poutanen +101

Recent observations of X-ray pulsars (XRPs) performed by the Imaging X-ray Polarimetry Explorer (IXPE) have made it possible to investigate the intricate details of these objects i…

astro-ph.HE2024

X-ray Polarization of the Black Hole X-ray Binary 4U 1630-47 Challenges Standard Thin Accretion Disk Scenario

Ajay Ratheesh, Michal Dovčiak, Henric Krawczynski +112

Large energy-dependent X-ray polarization degree is detected by the Imaging X-ray Polarimetry Explorer ({IXPE}) in the high-soft emission state of the black hole X-ray binary 4U 16…

astro-ph.HE2023

The detection of polarized x-ray emission from the magnetar 1E 2259+586

Jeremy Heyl, Roberto Taverna, Roberto Turolla +98

We report on IXPE, NICER and XMM-Newton observations of the magnetar 1E 2259+586. We find that the source is significantly polarized at about or above 20% for all phases except for…

astro-ph.HE2024

Studying geometry of the ultraluminous X-ray pulsar Swift J0243.6+6124 using X-ray and optical polarimetry

Juri Poutanen, Sergey S. Tsygankov, Victor Doroshenko +108

Discovery of pulsations from a number of ULXs proved that accretion onto neutron stars can produce luminosities exceeding the Eddington limit by several orders of magnitude. The co…

astro-ph.HE2023

X-ray Polarization of BL Lacertae in Outburst

Abel L. Peirson, Michela Negro, Ioannis Liodakis +128

We report the first confidence detection of X-ray polarization in BL Lacertae. During a recent X-ray/-ray outburst, a 287 ksec observation (2022 November 27-30) was ta…

astro-ph.HE2023

IXPE observations of the quintessential wind-accreting X-ray pulsar Vela X-1

Sofia V. Forsblom, Juri Poutanen, Sergey S. Tsygankov +97

The radiation from accreting X-ray pulsars was expected to be highly polarized, with some estimates for the polarization degree of up to 80%. However, phase-resolved and energy-res…

astro-ph.HE2023

IXPE and XMM-Newton observations of the Soft Gamma Repeater SGR 1806-20

Roberto Turolla, Roberto Taverna, Gian Luca Israel +96

Recent observations with the Imaging X-ray Polarimetry Explorer (IXPE) of two anomalous X-ray pulsars provided evidence that X-ray emission from magnetar sources is strongly polari…

astro-ph.HE2013

The Pierre Auger Observatory: Contributions to the 33rd International Cosmic Ray Conference (ICRC 2013)

The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu +495

Contributions of the Pierre Auger Collaboration to the 33rd International Cosmic Ray Conference, Rio de Janeiro, Brazil, July 2013

astro-ph.HE2026

Polarization of reflected X-ray emission from the Sgr A molecular complex: multiple flares, multiple sources?

Ildar Khabibullin, Eugene Churazov, Riccardo Ferrazzoli +100

The extended X-ray emission observed in the direction of several molecular clouds in the central molecular zone of our Galaxy exhibits spectral and temporal properties consistent w…

astro-ph.IM2022

Calibration of the IXPE focal plane X-ray polarimeters to polarized radiation

Alessandro Di Marco, Sergio Fabiani, Fabio La Monaca +80

IXPE (Imaging X-ray Polarimetry Explorer) is a NASA Small Explorer mission -- in partnership with the Italian Space Agency (ASI) -- dedicated to X-ray polarimetry in the 2--8 keV e…

astro-ph.HE2023

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…

astro-ph.HE2023

The First X-ray Polarization Observation of the Black Hole X-ray Binary 4U 1630-47 in the Steep Power Law State

Nicole Rodriguez Cavero, Lorenzo Marra, Henric Krawczynski +107

The Imaging X-ray Polarimetry Explorer (IXPE) observed the black hole X-ray binary 4U 1630-47 in the steep power law (or very high) state. The observations reveal a linear polariza…

astro-ph.HE2023

Determination of X-ray pulsar geometry with IXPE polarimetry

Victor Doroshenko, Juri Poutanen, Sergey S. Tsygankov +91

Using observations of X-ray pulsar Her X-1 by the Imaging X-ray Polarimetry Explorer, we report on a highly significant () detection of the polarization signal from an accre…

astro-ph.HE2025

X-ray Polarization Detection of the Pulsar Wind Nebula in G21.5-0.9 with IXPE

Niccolò Di Lalla, Nicola Omodei, Niccolò Bucciantini +98

We present the X-ray polarization observation of G21.5-0.9, a young Galactic supernova remnant (SNR), conducted with the Imaging X-ray Polarimetry Explorer (IXPE) in October 2023,…

astro-ph.HE2023

Discovery of X-ray Polarization from the Black Hole Transient Swift J1727.8-1613

Alexandra Veledina, Fabio Muleri, Michal Dovciak +113

We report the first detection of the X-ray polarization of the bright transient Swift J1727.8-1613 with the Imaging X-ray Polarimetry Explorer. The observation was performed at the…

astro-ph.IM2021

The Imaging X-Ray Polarimetry Explorer (IXPE): Pre-Launch

Martin C. Weisskopf, Paolo Soffitta, Luca Baldini +155

Scheduled to launch in late 2021, the Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Small Explorer Mission in collaboration with the Italian Space Agency (ASI). The mission w…

astro-ph.HE2022

Simultaneous space and phase resolved X-ray polarimetry of the Crab Pulsar and Nebula

Niccolò Bucciantini, Riccardo Ferrazzoli, Matteo Bachetti +93

The Crab pulsar and its nebula are among the most studied astrophysical systems, and constitute one of the most promising environments where high energy processes and particle acce…

astro-ph.HE2024

Discovery of a shock-compressed magnetic field in the north-western rim of the young supernova remnant RX J1713.7-3946 with X-ray polarimetry

Riccardo Ferrazzoli, Dmitry Prokhorov, Niccolò Bucciantini +99

Supernova remnants (SNRs) provide insights into cosmic-ray acceleration and magnetic field dynamics at shock fronts. Recent X-ray polarimetric measurements by the Imaging X-ray Pol…

astro-ph.HE2024

Pulsar-wind-nebula-powered Galactic center X-ray filament G0.13-0.11: Proof of the synchrotron nature by IXPE

Eugene Churazov, Ildar Khabibullin, Thibault Barnouin +103

We report the discovery of X-ray polarization from the X-ray-bright filament. G0.13-0.11 in the Galactic center (GC) region. This filament features a bright, hard X-ray source that…

astro-ph.HE2023

X-ray pulsar GRO J100857 as an orthogonal rotator

Sergey S. Tsygankov, Victor Doroshenko, Alexander A. Mushtukov +99

X-ray polarimetry is a unique way to probe the geometrical configuration of highly magnetized accreting neutron stars (X-ray pulsars). GRO J100857 is the first transient X-ray p…

astro-ph.HE2023

X-ray polarimetry reveals the magnetic field topology on sub-parsec scales in Tycho's supernova remnant

Riccardo Ferrazzoli, Patrick Slane, Dmitry Prokhorov +97

Supernova remnants are commonly considered to produce most of the Galactic cosmic rays via diffusive shock acceleration. However, many questions about the physical conditions at sh…

astro-ph.HE2023

Discovery of X-ray polarization angle rotation in active galaxy Mrk 421

Laura Di Gesu, Herman L. Marshall, Steven R. Ehlert +140

The magnetic field conditions in astrophysical relativistic jets can be probed by multiwavelength polarimetry, which has been recently extended to X-rays. For example, one can trac…

astro-ph.HE2023

First detection of X-ray polarization from the accreting neutron star 4U 1820-303

Alessandro Di Marco, Fabio La Monaca, Juri Poutanen +116

This paper reports the first detection of polarization in the X-rays for atoll-source 4U 1820-303, obtained with the Imaging X-ray Polarimetry Explorer (IXPE) at 99.999% confidence…

astro-ph.HE2023

A polarimetrically oriented X-ray stare at the accreting pulsar EXO 2030+375

Christian Malacaria, Jeremy Heyl, Victor Doroshenko +104

Accreting X-ray pulsars (XRPs) are presumably ideal targets for polarization measurements, as their high magnetic field strength is expected to polarize the emission up to a polari…

astro-ph.HE2023

X-ray Polarization Reveals the Precessions of the Neutron Star in Hercules X-1

Jeremy Heyl, Victor Doroshenko, Denis González-Caniulef +100

In an accreting X-ray pulsar, a neutron star accretes matter from a stellar companion through an accretion disk. The high magnetic field of the rotating neutron star disrupts the i…

astro-ph.HE2023

The IXPE view of GRB 221009A

Michela Negro, Niccoló Di Lalla, Nicola Omodei +108

We present the IXPE observation of GRB 221009A which includes upper limits on the linear polarization degree of both prompt and afterglow emission in the soft X-ray energy band. GR…

astro-ph.HE2023

A strong X-ray polarization signal from the magnetar 1RXS J170849.0-400910

Silvia Zane, Roberto Taverna, Denis Gonzalez Caniulef +99

Magnetars are the most strongly magnetized neutron stars, and one of the most promising targets for X-ray polarimetric measurements. We present here the first Imaging X-ray Polarim…

astro-ph.HE2023

Discovery of a variable energy-dependent X-ray polarization in the accreting neutron star GX 5-1

Sergio Fabiani, Fiamma Capitanio, Rosario Iaria +116

We report on the coordinated observations of the neutron star low-mass X-ray binary (NS-LMXB) \gx in X-rays (IXPE, NICER, Nustar and INTEGRAL), optical (REM and LCO), near-infrared…

astro-ph.HE2023

Magnetic structures and turbulence in SN 1006 revealed with imaging X-ray polarimetry

Ping Zhou, Dmitry Prokhorov, Riccardo Ferrazzoli +99

Young supernova remnants (SNRs) strongly modify surrounding magnetic fields, which in turn play an essential role in accelerating cosmic rays (CRs). X-ray polarization measurements…

astro-ph.HE2020

Theoretical interpretation of Pass 8 Fermi-LAT data

Mattia Di Mauro, Silvia Manconi, Andrea Vittino +12

The flux of positrons and electrons () has been measured by the Large Area Telescope (LAT) in the energy range between 7 GeV and 2 TeV. We discuss a number of in…

astro-ph.HE2024

Analysis of Crab X-ray Polarization using Deeper IXPE Observations

Josephine Wong, Tsunefumi Mizuno, Niccoló Bucciantini +98

We present Crab X-ray polarization measurements using IXPE data with a total exposure of 300ks, three times more than the initial 2022 discovery paper. Polarization is detected in…

astro-ph.HE2023

First X-ray polarization measurement confirms the low black-hole spin in LMC X-3

Jiří Svoboda, Michal Dovčiak, James F. Steiner +109

X-ray polarization is a powerful tool to investigate the geometry of accreting material around black holes, allowing independent measurements of the black hole spin and orientation…

astro-ph.IM2023

Joint machine learning and analytic track reconstruction for X-ray polarimetry with gas pixel detectors

Nicoló Cibrario, Michela Negro, Nikita Moriakov +9

We present our study on the reconstruction of photoelectron tracks in gas pixel detectors used for astrophysical X-ray polarimetry. Our work aims to maximize the performance of con…

astro-ph.HE2025

X-ray Polarization of the High-Synchrotron-Peak BL Lacertae Object 1ES 1959+650 during Intermediate and High X-ray Flux States

Luigi Pacciani, Dawoon E. Kim, Riccardo Middei +97

We report the Imaging X-ray Polarimetry Explorer (IXPE) polarimetric and simultaneous multiwavelength observations of the high-energy-peaked BL Lacertae (HBL) object 1ES 1959+650,…

astro-ph.HE2023

Polarized x-rays constrain the disk-jet geometry in the black hole x-ray binary Cygnus X-1

Henric Krawczynski, Fabio Muleri, Michal Dovčiak +111

A black hole x-ray binary (XRB) system forms when gas is stripped from a normal star and accretes onto a black hole, which heats the gas sufficiently to emit x-rays. We report a po…

astro-ph.HE2022

Limits on X-ray Polarization at the Core of Centaurus A as Observed with the Imaging X-ray Polarimetry Explorer

Steven R. Ehlert, Riccardo Ferrazzoli, Andrea Marinucci +95

We present measurements of the polarization of X-rays in the band from the nucleus of the radio galaxy Centaurus A (Cen A), using a 100ks observation…