Publications (74)
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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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)…
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…
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-…
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…
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…
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…
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…
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…
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 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…
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…
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…
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…
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…
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…
Comparative analysis of local angular rotation between the Ring Laser Gyroscope GINGERINO and GNSS stations
Giuseppe Di Somma, Nicolò Beverini, Giorgio Carelli +5
The study of local deformations is a hot topic in geodesy. Local rotations of the crust around the vertical axis can be caused by deformations. In the Gran Sasso area the ring lase…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
Fringe Contrast characterization and optimization for Ring Laser Gyroscopes
Nicolò Beverini, Giorgio Carelli, Simone Castellano +4
Top sensitivity Ring Laser Gyroscopes based on a simple mechanical scheme, so called heterolithic, have shown to operate on a continuous basis; since the mirror positions are not f…
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…
X-ray Polarization of the Black Hole X-ray Binary 4U 1630-47 Challenges Standard Thin Accretion Disk Scenario
Ajay Ratheesh, Michal DovÄiak, 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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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,…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
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…
Status of the GINGER project
Carlo Altucci, Francesco Bajardi, Andrea Basti +20
Large frame Ring laser gyroscopes, based on the Sagnac effect, are top sensitivity instrumentation to measure angular velocity with respect to the fixed stars. GINGER (Gyroscopes I…
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…
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…
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…
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…
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…
First X-ray polarization measurement confirms the low black-hole spin in LMC X-3
JiÅÃ Svoboda, Michal DovÄiak, 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…
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,…
Polarized x-rays constrain the disk-jet geometry in the black hole x-ray binary Cygnus X-1
Henric Krawczynski, Fabio Muleri, Michal DovÄiak +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…
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…