Search Publications
Discovery of a variable energy-dependent X-ray polarization in the accreting neutron star GX 5−1
Kaaret, Philip; Wu, Kinwah; Steiner, James F. +116 more
We report on the coordinated observations of the neutron star low-mass X-ray binary (NS-LMXB) GX 5−1 in X-rays (IXPE, NICER, NuSTAR, and INTEGRAL), optical (REM and LCO), near-infrared (REM), mid-infrared (VLT VISIR), and radio (ATCA). This Z-source was observed by IXPE twice in March-April 2023 (Obs. 1 and 2). In the radio band the source was det…
GRB 180128A: A second magnetar giant flare candidate from the Sculptor Galaxy
Andreoni, Igor; Frederiks, Dmitry D.; Svinkin, Dmitry S. +14 more
Magnetars are slowly rotating neutron stars that possess the strongest magnetic fields known in the cosmos (1014 − 1015 G). They display a range of transient high-energy electromagnetic activity. The brightest and most energetic of these events are the gamma-ray bursts (GRBs) known as magnetar giant flares (MGFs), with isotro…
A catalogue of low-mass X-ray binaries in the Galaxy: From the INTEGRAL to the Gaia era
Chaty, S.; García, F.; Fortin, F. +2 more
Context. Low-mass X-ray binaries (LMXBs) are high-energy sources that require multi-wavelength follow-up campaigns to be fully characterised. New transients associated with LMXBs are regularly discovered, and previously known systems are often revisited by astronomers to constrain their intrinsic parameters. All of this information compiled into a…
Long term variability of Cygnus X-1. VIII. A spectral-timing look at low energies with NICER
Ingram, Adam; Steiner, James F.; Grinberg, Victoria +19 more
The Neutron Star Interior Composition Explorer (NICER) monitoring campaign of Cyg X-1 allows us to study its spectral-timing behavior at energies < 1 keV across all states. The hard state power spectrum can be decomposed into two main broad Lorentzians with a transition at around 1 Hz. The lower-frequency Lorentzian is the dominant component at…
SRG/ART-XC all-sky X-ray survey: Catalog of sources detected during the first five surveys
Sunyaev, R.; Krivonos, R.; Sazonov, S. +27 more
We present an updated catalog of sources detected by the Mikhail Pavlinsky ART-XC telescope aboard the Spektrum-Roentgen-Gamma (SRG) observatory during its all-sky survey. It is based on the data of the first four and the partially completed fifth scans of the sky (ARTSS1-5). The catalog comprises 1545 sources detected in the 4-12 keV energy band.…
INTEGRAL/IBIS polarization detection in the hard and soft intermediate states of Swift J1727.8−1613
Rodriguez, J.; Wilms, J.; Laurent, P. +5 more
Aims: Soft γ-ray emission (100 keV-10 MeV) has previously been detected in the hard state of several microquasars. In some sources, this emission was found to be highly polarized and was suggested to be emitted at the base of the jet. Until now, no γ-ray polarization had been found in any other state.
Methods: Using INTEGRAL/IBIS, we stu…
INTEGRAL view of GRB 221009A. Prompt energetics and week-long hard X-ray afterglow
Mereghetti, Sandro; Tiengo, Andrea; Kuulkers, Erik +11 more
The gamma-ray burst GRB 221009A is among the most luminous of its kind and its proximity to Earth has made it an exceptionally rare observational event. The International Gamma-ray Astrophysics Laboratory (INTEGRAL) was in an optimal aspect position to use its all-sky instruments for recording the prompt emission and early gamma-ray afterglow in u…
Early photometric and spectroscopic observations of the extraordinarily bright INTEGRAL-detected GRB 221009A
Sánchez-Ramírez, R.; Pandey, S. B.; Castro-Tirado, A. J. +46 more
Context. GRB 221009A, initially detected as an X-ray transient by Swift, was later revealed to have triggered the Fermi satellite about an hour earlier, marking it as a post-peak observation of the event's emission. This GRB distinguished itself as the brightest ever recorded, presenting an unparalleled opportunity to probe the complexities of GRB…
Constraining the overcontact phase in massive binary evolution: III. Period stability of known B+B and O+B overcontact systems
Mahy, Laurent; Abdul-Masih, Michael; Marchant, Pablo +3 more
Context. Binary systems play a crucial role in massive star evolution. Systems composed of B-type and O-type stars are of particular interest due to their potential to lead to very energetic phenomena or the merging of exotic compact objects. Aims. We aim to determine the orbital period variations of a sample of B+B and O+B massive overcontact bin…
Spectral and timing properties of the accreting millisecond X-ray pulsar IGR J17498‑2921 during its 2023 outburst
Sanna, A.; Papitto, A.; Di Salvo, T. +13 more
We present a comprehensive study of the spectral properties of the accreting millisecond X-ray pulsar IGR J17498‑2921 during its 2023 outburst. Similar to other accreting millisecond X-ray pulsars, the broadband spectral emission observed quasi-simultaneously by NICER and NuSTAR is well described by an absorbed Comptonized emission with an electro…