Publications (157)
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…
A candidate proton cyclotron feature in the ultraluminous X-ray source NGC 4656 ULX-1
Nelson Cruz-Sanchez, Enzo A. Saavedra, Federico A. Fogantini +6
Ultraluminous X-ray sources represent extreme super-Eddington accretion regimes, and a subset is now known to host highly magnetized neutron stars. However, direct observational pr…
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,…
Synchrotron radiation from NGC 470 HLX1 - a hidden hyperluminous accreting neutron star?
Tanuman Ghosh, Shiv Sethi, Gulab Chand Dewangan +3
We present the first broadband spectral analysis of NGC 470 HLX1, a hyperluminous X-ray source that exhibits significant flux variability over different epochs. We investigate the…
Magnetar-like activity from the central compact object in the SNR RCW103
Nanda Rea, Alice Borghese, Paolo Esposito +4
The 6.67 hr periodicity and the variable X-ray flux of the central compact object (CCO) at the center of the SNR RCW 103, named 1E 161348-5055, have been always difficult to interp…
Calibration of the NuSTAR High Energy Focusing X-ray Telescope
Kristin K. Madsen, Fiona A. Harrison, Craig B. Markwardt +19
We present the calibration of the \textit{Nuclear Spectroscopic Telescope Array} (\nustar) X-ray satellite. We used the Crab as the primary effective area calibrator and constructe…
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…
IXPE view of the Crab pulsar following the 17 July and 6 August 2025 glitches
Paolo Soffitta, Niccolò Bucciantini, Josephine Wong +19
The Crab pulsar experienced two relatively small glitches separated by only 20 days in September and October 2025. IXPE observed the source twice, with delay times since the glitch…
Discovering periodic and repeating nuclear transients in the XMM-Newton archives
Natalie A. Webb, Vincent Foustoul, Robbie Webbe +3
The regions around massive black holes can show X-ray variability on timescales from seconds to decades. Observing many black holes over different timescales can enhance our chance…
PINT: Maximum-likelihood estimation of pulsar timing noise parameters
Abhimanyu Susobhanan, David Kaplan, Anne Archibald +21
PINT is a pure-Python framework for high-precision pulsar timing developed on top of widely used and well-tested Python libraries, supporting both interactive and programmatic data…
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…
Peering through the dip: IXPE unveils the extended scattering environment of GX 13+1
Alessandro Di Marco, Fabio La Monaca, Luigi Stella +17
Neutron star low-mass X-ray binaries feature complex accretion geometries, often including an accretion disk corona or disk winds. Here, a study of the highly inclined dipping sour…
The Reflection Component from Cygnus X-1 in the Soft State Measured by NuSTAR and Suzaku
John A. Tomsick, Michael A. Nowak, Michael Parker +21
The black hole binary Cygnus X-1 was observed in late-2012 with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku, providing spectral coverage over the ~1-300 keV range…
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…
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…
The Advanced X-ray Imaging Satellite (AXIS) Community Science Book
Michael Koss, Nafisa Aftab, Steven W. Allen +395
The AXIS Community Science Book represents the collective effort of 592 scientists worldwide to define the transformative science enabled by the Advanced X-ray Imaging Satellite (A…
The Broadband XMM-Newton and NuSTAR X-ray Spectra of Two Ultraluminous X-ray Sources in the Galaxy IC 342
Vikram Rana, Fiona A. Harrison, Matteo Bachetti +15
We present results for two Ultraluminous X-ray Sources (ULXs), IC 342 X-1 and IC 342 X-2, using two epochs of XMM-Newton and NuSTAR observations separated by 7 days. We obser…
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…
NuSTAR observations of magnetar 1E 1841-045
Hongjun An, Romain Hascoet, Victoria M. Kaspi +18
We report new spectral and temporal observations of the magnetar 1E 1841-045 in the Kes 73 supernova remnant obtained with the Nuclear Spectroscopic Telescope Array (NuSTAR). Combi…
A ~60-day super-orbital period originating from the ultraluminous X-ray pulsar in M82
Murray Brightman, Fiona A. Harrison, Matteo Bachetti +6
Ultraluminous X-ray (ULX) pulsars are a new class of object powered by apparent super-critical accretion onto magnetized neutron stars. Three sources in this class identified so fa…
Equalizing the Pixel Response of the Imaging Photoelectric Polarimeter On-Board the IXPE Mission
John Rankin, Fabio Muleri, Alessandro Di Marco +18
The Gas Pixel Detector is a gas detector, sensitive to the polarization of X-rays, currently flying on-board IXPE - the first observatory dedicated to X-ray polarimetry. It detects…
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-…
The slowest spinning X-ray pulsar in an extragalactic globular cluster
Ivan Zolotukhin, Matteo Bachetti, Nicola Sartore +2
Neutron stars are thought to be born rapidly rotating and then exhibit a phase of a rotation-powered pulsations as they slow down to 1-10 s periods. The significant population of m…
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…
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…
Probing the Black Hole Engine with Measurements of the Relativistic X-ray Reflection Component
Javier A. GarcÃa, Matteo Bachetti, David R. Ballantyne +21
Over the last decades X-ray spectroscopy has proven to be a powerful tool for the estimation of black hole spin and several other key parameters in dozens of AGN and black hole X-r…
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…
Correlation between active regions' spectra at high radio frequencies and solar flare occurrences
Sara Mulas, Alberto Pellizzoni, Marco Marongiu +31
High radio frequencies observations with the Italian network of large single-dish radio telescopes resulted in ~450 solar images between 2018 and 2023 in K-band frequency range (18…
A NuSTAR study of quasi-periodic oscillations from the ultraluminous X-ray sources in M82
Hamza El Byad, Matteo Bachetti, Silvia Columbu +13
The study of quasi-periodic oscillations in X-ray binaries provides valuable insights into the physics of accretion around compact objects. The M82 galaxy hosts two ultraluminous X…
Extending the and statistics to generic pulsed profiles
Matteo Bachetti, Maura Pilia, Daniela Huppenkothen +3
The search for astronomical pulsed signals within noisy data, in the radio band, is usually performed through an initial Fourier analysis to find "candidate" frequencies and then r…
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…
Hard X-ray flares and spectral variability in NGC 4395 ULX1
Tanuman Ghosh, Vikram Rana, Matteo Bachetti
We report the detection of flaring events in NGC 4395 ULX1, a nearby ultraluminous X-ray source (ULX), for the first time, using recent XMM-NEWTON observations. The flaring episode…
Skipping a beat: discovery of persistent quasi-periodic oscillations associated with pulsed fraction drop of the spin signal in M51 ULX-7
Matteo Imbrogno, Sara Elisa Motta, Roberta Amato +24
The discovery of pulsations in (at least) six ultraluminous X-ray sources (ULXs) has shown that neutron stars can accrete at (highly) super-Eddington rates, challenging the standar…
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…
X-ray Dips and Polarization Angle Swings in GX 13+1
Alessandro Di Marco, Fabio La Monaca, Anna Bobrikova +8
We present the result from the April 2024 observation of the low-mass X-ray binary GX 13+1 with the Imaging X-ray Polarimetry Explorer (IXPE), together with NICER and Swift-XRT coo…
Evolution of the spin, spectrum and super-orbital period of the ultraluminous X-ray pulsar M51 ULX7
Murray Brightman, Matteo Bachetti, Hannah Earnshaw +6
M51 ULX7 is among a small group of known ultraluminous X-ray pulsars (ULXP). The neutron star powering the source has a spin period of 2.8s, orbits its companion star with a period…
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…
A joint MeerKAT and Parkes view of Omega Centauri: New TRAPUM Searches and Pulsar Timing
Miquel Colom i Bernadich, Shi Dai, Federico Abbate +27
Millisecond pulsars (MSPs) are powerful probes of globular clusters (GCs), tracing stellar evolution, cluster dynamics, and the local gravitational potential. We investigate the MS…
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…
A Hard X-Ray Power-Law Spectral Cutoff in Centaurus X-4
Deepto Chakrabarty, John A. Tomsick, Brian W. Grefenstette +17
The low-mass X-ray binary Cen X-4 is the brightest and closest (<1.2 kpc) quiescent neutron star transient. Previous 0.5-10 keV X-ray observations of Cen X-4 in quiescence identifi…
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…
The IXPE Instrument Calibration Equipment
Fabio Muleri, Raffaele Piazzolla, Alessandro Di Marco +28
The Imaging X-ray Polarimetry Explorer is a mission dedicated to the measurement of X-ray polarization from tens of astrophysical sources belonging to different classes. Expected t…
Orbital decay in M82 X-2
Matteo Bachetti, Marianne Heida, Thomas Maccarone +21
M82 X-2 is the first pulsating ultraluminous X-ray source (PULX) discovered. The luminosity of these extreme pulsars, if isotropic, implies an extreme mass transfer rate. An altern…
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…
The High Energy X-ray Probe (HEX-P): resolving the nature of Sgr A* flares, compact object binaries and diffuse X-ray emission in the Galactic Center and beyond
Kaya Mori, Gabriele Ponti, Matteo Bachetti +24
HEX-P is a probe-class mission concept that will combine high spatial resolution X-ray imaging ( FWHM) and broad spectral coverage (0.2-80 keV) with an effective area far sup…
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…
Kes 75 with IXPE: Detection of Nebular X-ray Polarization and Change in Pulsar Lightcurve
Josephine Wong, Jack T. Dinsmore, Roger W. Romani +16
We present the first X-ray polarization measurements of the PSR/PWN complex within SNR Kes 75. Two IXPE observations were conducted in October/November 2024 a…
NuSTAR discovery of an unusually steady long-term spin-up of the Be binary 2RXP J130159.6-635806
Roman A. Krivonos, Sergey S. Tsygankov, Alexander A. Lutovinov +14
We present spectral and timing analysis of NuSTAR observations of the accreting X-ray pulsar 2RXP J130159.6-635806. The source was serendipitously observed during a campaign focuse…
On the magnetic field in M51 ULX-8
Matthew Middleton, Murray Brightman, Fabio Pintore +4
The reported discovery of a cyclotron resonance scattering feature (CRSF) in the spectrum of M51 ULX-8 may provide an important clue as to the nature of the magnetic field in those…
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…
The NuSTAR view of the non-thermal emission from PSR J0437-4715
Sebastien Guillot, Victoria M. Kaspi, Robert F. Archibald +11
We present a hard X-ray NuSTAR observation of PSR J0437-4715, the nearest millisecond pulsar. The known pulsations at the apparent pulse period ~5.76 ms are detected at energies up…
A broadband X-ray study of the Geminga pulsar with NuSTAR and XMM-Newton
Kaya Mori, Eric V. Gotthelf, Francois Dufour +14
We report on the first hard X-ray detection of the Geminga pulsar above 10 keV using a 150 ks observation with the NuSTAR observatory. The double-peaked pulse profile of non-therma…
ULX spectra revisited: Accreting, highly magnetized neutron stars as the engines of ultraluminous X-ray sources
Filippos Koliopanos, Georgios Vasilopoulos, Olivier Godet +3
Aims: In light of recent discoveries of pulsating ULXs and recently introduced models, that propose neutron stars (NSs) as the central engines of ULXs, we revisit the (XMM-Newton a…
Phase-resolved NuSTAR and Swift-XRT Observations of Magnetar 4U 0142+61
Shriharsh P. Tendulkar, Romain Hascöet, Chengwei Yang +12
We present temporal and spectral analysis of simultaneous 0.5-79 keV Swift-XRT and NuSTAR observations of the magnetar 4U 0142+61. The pulse profile changes significantly with phot…
The ultraluminous X-ray sources NGC 1313 X-1 and X-2: a broadband study with NuSTAR and XMM-Newton
Matteo Bachetti, Vikram Rana, Dominic J. Walton +16
We present the results of NuSTAR and XMM-Newton observations of the two ultraluminous X-ray sources (ULX) NGC 1313 X-1 and X-2. The combined spectral bandpass of the two satellites…
NuSTAR results and future plans for magnetar and rotation-powered pulsar observations
Hongjun An, Victoria M. Kaspi, Robert Archibald +27
The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing hard X-ray mission in orbit and operates in the 3-79 keV range. NuSTAR's sensitivity is roughly two orders…
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…
A simple, flexible method for timing cross-calibration of space missions
Matteo Bachetti, Yukikatsu Terada, Megumi Shidatsu +25
The timing (cross-)calibration of astronomical instruments is often done by comparing pulsar times-of-arrival (TOAs) to a reference timing model. In high-energy astronomy, the choi…
A multi-wavelength pipeline for pulsar searches
Maura Pilia, Alessio Trois, Matteo Bachetti +7
Pulsar studies in the recent years have shown, more than others, to have benefited from a multi-wavelength approach. The INAF - Astronomical Observatory in Cagliari (INAF-OAC) is a…
Long term variability of Cygnus X-1. IX. A spectral-timing comparison of Cygnus X-1 and MAXI J1820+070 in the hard state
Arkadip Basak, Phil Uttley, Niek Bollemeijer +11
Cygnus X-1 is a persistent, high-mass black hole X-ray binary (BHXRB) which in the hard state shows many similar properties to transient BHXRBs, along with intriguing differences,…
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…
The Science of the Einstein Telescope
Adrian Abac, Raul Abramo, Simone Albanesi +485
Einstein Telescope (ET) is the European project for a gravitational-wave (GW) observatory of third-generation. In this paper we present a comprehensive discussion of its science ob…
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,…
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…
Magnetic field strength of a neutron-star-powered ultraluminous X-ray source
Murray Brightman, Fiona A. Harrison, Felix Fuerst +7
Ultraluminous X-ray sources (ULXs) are bright X-ray sources in nearby galaxies not associated with the central supermassive black hole. Their luminosities imply they are powered by…
Timing Calibration of the NuSTAR X-ray Telescope
Matteo Bachetti, Craig B. Markwardt, Brian W. Grefenstette +13
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission is the first focusing X-ray telescope in the hard X-ray (3-79 keV) band. Among the phenomena that can be studied in this…
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…
No Time for Dead Time: Use the Fourier Amplitude Differences to Normalize Dead-time-affected Periodograms
Matteo Bachetti, Daniela Huppenkothen
Dead time affects many of the instruments used in X-ray astronomy, by producing a strong distortion in power density spectra. This can make it difficult to model the aperiodic vari…
The High Energy X-ray Probe: Resolved X-ray Populations in Extragalactic Environments
Bret D. Lehmer, Kristen Garofali, Breanna A. Binder +15
We construct simulated galaxy data sets based on the High Energy X-ray Probe (HEX-P) mission concept to demonstrate the significant advances in galaxy science that will be yielded…
A search for hyperluminous X-ray sources in the XMM-Newton source catalog
Ivan Zolotukhin, Natalie A. Webb, Olivier Godet +2
We present a new method to identify luminous off-nuclear X-ray sources in the outskirts of galaxies from large public redshift surveys, distinguishing them from foreground and back…
The smooth cyclotron line in Her X-1 as seen with NuSTAR
Felix Fuerst, Brian W. Grefenstette, Ruediger Staubert +17
Her X-1, one of the brightest and best studied X-ray binaries, shows a cyclotron resonant scattering feature (CRSF) near 37 keV. This makes it an ideal target for detailed study wi…
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…
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…
The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
Fiona A. Harrison, William W. Craig, Finn E. Christensen +77
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 13 June 2012, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in the band from 3…
Modelling high-resolution spatially-resolved Supernova Remnant spectra with the Sardinia Radio Telescope
Sara Loru, Alberto Pellizzoni, Elise Egron +12
Supernova Remnants (SNRs) exhibit spectra featured by synchrotron radio emission arising from the relativistic electrons, and high-energy emission from both leptonic (Bremsstrahlun…
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…
Ultraluminous X-ray sources: three exciting years
Matteo Bachetti
The extreme extragalactic sources known as Ultraluminous X-ray Sources (ULX) represent a unique testing environment for compact objects population studies and the accretion process…
Spectral and Timing Analysis of NuSTAR and Swift/XRT Observations of the X-Ray Transient MAXI J0637-430
Hadar Lazar, John A. Tomsick, Sean N. Pike +10
We present results for the first observed outburst from the transient X-ray binary source MAXI J0637-430. This study is based on eight observations from the Nuclear Spectroscopic T…
All at once: transient pulsations, spin down and a glitch from the Pulsating Ultraluminous X-ray Source M82 X-2
Matteo Bachetti, Thomas J. Maccarone, Murray Brightman +9
M82 X-2 is the first pulsating ultraluminous X-ray source (PULX)to be identified. Since the discovery in 2014, NuSTAR has observed the M82 field 15 times throughout 2015 and 2016.…
The drop of the coherence of the lower kHz QPOs is also observed in XTE J1701-462
Didier Barret, Matteo Bachetti, M. Coleman Miller
We investigate the quality factor and RMS amplitude of the lower kHz QPOs from XTE J1701-462, a unique X-ray source which was observed in both the so-called Z and atoll states. Cor…
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…
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…
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…
A multiwavelength study of the Galactic center black hole candidate MAXI J1744-294
Shifra Mandel, Kaya Mori, Paul A. Draghis +37
For the first time in nearly a decade, a bright transient was detected in the central parsec (pc) of the Galaxy. MAXI J1744-294, or -- as it was known in its previous life -- Swift…
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…
QPO emission from moving hot spots on the surface of neutron stars: a model
Matteo Bachetti, Marina Romanova, Akshay Kulkarni +2
We present recent results of 3D magnetohydrodynamic simulations of neutron stars with small misalignment angles, as regards the features in lightcurves produced by regular movement…
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…
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…
The X-ray Polarization Probe mission concept
Keith Jahoda, Henric Krawczynski, Fabian Kislat +100
The X-ray Polarization Probe (XPP) is a second generation X-ray polarimeter following up on the Imaging X-ray Polarimetry Explorer (IXPE). The XPP will offer true broadband polarim…
NuSTAR and INTEGRAL observations of a low/hard state of 1E1740.7-2942
Lorenzo Natalucci, John A. Tomsick, Angela Bazzano +19
The microquasar 1E1740.7-2942, also known as the "Great Annihilator", was observed by NuSTAR in the Summer of 2012. We have analyzed in detail two observations taken ~2 weeks apart…