Jets provide an important channel of kinetic feedback from accreting black holes into their environments. In the absence of instantaneous jet power measurements the extent of this feedback has proven difficult to quantify. Here we report the detection of stellar wind-induced bending of the jets in black hole X-ray binary Cygnus X-1, using 18 years of high-resolution radio imaging. By...
The X-ray flux from black hole X-ray binaries in the hard state is highly variable on a broad range of timescales. On a timescale of seconds, such broadband noise is thought to arise in the turbulent accretion disk and propagated to the corona, which emits harder X-rays in the spectral shape of a powerlaw with a cut-off. The nature and geometry of the corona is subject to debate, but there is...
We compare observations at radio wavelengths made along three decades toward the prototypical galactic microquasar. In the year 2023 the source presented major changes with respect to the historical values since 1994. The position angle of the bipolar ejecta in the plane of the sky has increased counter-clockwise by 24◦. The inclination angle of the flow with respect to the line of sight...
Jets from stellar mass black holes in X-ray binaries (XRBs) and supermassive black holes in blazars provide distinct opportunities to study the jets of black holes across two different mass regimes. They also represent samples with very different selection effects. Historically, the apparent speeds of XRB jets have been observed to be lower than those of blazars, leading to the assumption that...
Ultraluminous X-ray sources (ULXs) are accreting stellar compact objects whose X-ray luminosities exceed the Eddington limit. In order to get more insights on the nature of their accreting compact object (black hole or neutron star) and the geometries of super-Eddington accretion flows, it is useful to look at the influence of ULXs on their environment. I will present how VLT/MUSE 3-D...
Previous observational and simulation work has explored the role the kink instability (KI) could play in explaining the phenomenology of active galactic nuclei jets and gamma ray bursts. Internal modes of this instability have been shown to drive conversion of magnetic energy into thermal energy without disrupting the overall flow of the jet. We suggest that these modes may therefore be able...
Black Hole X-ray binaries (BHXBs) serve as powerful laboratories for studying relativistic jets and their impact on the surrounding medium. MAXI J1348-630 is a BHXB that was recently discovered in outburst. This source was shown to exhibit strong radio jets with a distinct deceleration pattern of motion, indicative of the presence of a jet-blown cavity in the interstellar medium (ISM)....
We investigate the 2018 main outburst and the subsequent mini-outbursts of the black hole low-mass X-ray binary MAXI J1820+070 using optical/ultraviolet data from the Las Cumbres Observatory (LCO), the American Association of Variable Star Observers (AAVSO), and SWIFT/UVOT, as well as X-ray data from Insight-HXMT and SWIFT/XRT. Given the high-cadence observations, we identify a broad dip-like...
One of the most amazing microquasars is the Cyg X-3 binary system with a black hole and a massive Wolf-Rayet star. In 2024, during multi-frequency monitoring with the RATAN-600 radio telescope, we detected five giant (>10Jy) flares from Cyg X-3. The onsets of flares was clearly associated with the detection of significant Gamma-ray radiation at 0.1-300 GeV (Fermi space observatory). The...
Recent endeavors to directly classify the donor star mass of extragalactic X-ray binaries (XRBs) through optical photometric modeling has uncovered an apparent overabundance of XRBs with donor stars with a mass between 3 and 8 solar masses. These so-called 'intermediate-mass XRBs' (IMXBs) make up as many as 30% of the XRBs in nearby spiral galaxies. A population of this size is in...
Black hole X-ray binaries in outburst launch discrete, large-scale jet ejections which can propagate to parsec scales. The kinematics of these ejecta appear to be well described by relativistic blast wave models originally devised for gamma-ray burst afterglows. In kinematic-only modelling a crucial degeneracy prevents the ejecta energy and interstellar medium density from being accurately...
We have used The Chandra Source Catalog to extract light curves of point sources from nearby galaxies, ULXs, and 25 nearby (z lt 0.2) QSOs. We have Chandra grating observations of 25 Galactic XRBs adjusted to ACIS count rates at a distance of 1 Mpc. A three-dimensional color-color-RelInt diagram shows that the distribution of ULXs is well matched in both color and luminosity with point...
Studying the chemical composition of accretion discs around compact objects, such as neutron stars in low-mass X-ray binaries (LMXBs), provides vital information about their formation and evolutionary history. This touches on a range of important topics, including key uncertainties in binary evolution such as mass transfer efficiency and common-envelope phases, that in turn impact the...
The spectral modelling of accreting X-ray pulsars is difficult owing to the anisotropy linked to the strong magnetic field and the geometrical properties such as the inclination of the line of sight and the location of the magnetic poles. This strongly influences the observed phase variability at the spin frequency. In Ferrigno et al. (2023), we introduced a method to compute pulsed profiles...
The Imaging X-ray Polarimetry Explorer (IXPE) is opening a new observational window into the physics of weakly magnetized neutron stars in low-mass X-ray binaries (LMXBs). In particular, coordinated multi-instrument campaigns have enabled the first systematic studies of the polarization signatures from bright Atoll-type sources. In this contribution, we focus on the source GX 9+1 and present...
I will discuss recent results of the radiation effect on magnetically-arrested disks (MAD) around rotating black holes and the resulting jets, obtained using the general-relativistic radiative magneto-hydrodynamic (GR-R-MHD) code cuHARM. I will show that (i) The jet width, MAD parameter and jet efficiency increase with the accretion rate, before saturation caused by gas-pressure to...
Resolving spatially the complex emission geometry of the micro-quasar SS433 requires interferometric observations to be understood. SS433 is likely composed of a black hole accreting from a massive star. Multi-wavelength observations show an unresolved accretion disk, a more extended circumbinary outflow of variable geometry and the presence of cold dust.
The systems present two precessing...
We present a reanalysis of archive radio interferometric data for the gamma-ray binary LS I +61303. Our aim is to expand our previous searches for associated extended emission at the few arc-second/arc-minute level. The existence of such large scale features is expected no matter the physical scenario that is really at work in this system: pulsar wind interaction or microquasar. The main...
Spectral-timing analyses are a key tool to investigate the innermost region in accreting X-ray sources.
However, when encounter them, such techniques can appear strenuous to implement and use in an easy way. An advantageous way is to rely on well-maintained and reliable software such as Stingray.
Stingray is an open-source Python library that is able to compute the main Fourier analyses...
The BHB GRS~1915+105 was bright for 26 years since its discovery and is well known for its disk instabilities, quasi-periodic oscillations, and disk wind signatures. We report a long-term spectral-timing tracing of this source from mid-2017 until the onset of the so-called obscured state based on the complete data from NICER and other potential X-ray missions. In the soft state predating 2018,...
Strong radio flare events were detected in black hole X-ray binary system 4U 1543-47 by MeerKAT. In this work, we investigated X-ray observation data during these periods. Our results suggest a four-step jet cycle: (1) the accretion disk is full, (2) the inner disk becomes unstable, (3) the jet is formed, (4) the disk refills.
Accretion states, which are universally observed in stellar-mass black holes in X-ray binaries, are also anticipated in active galactic nuclei (AGN). The luminosity-excitation diagram (LED), based on IR nebular emission-line ratios, successfully identifies distinct accretion regimes in AGN —from jet/corona-dominated emission in low-luminosity AGN (LLAGN) to disc-dominated emission in Seyfert...
Currently a sample of 5 microquasars are reported by LHASSO to have ultrahigh-energies (UHE, above 100TeV) emissions which remains a puzzle for the mechanism underneath. Among this sample, evidences of jet-dominated X-ray emissions were revealed from MAXI J1820+070 during an outburst well observed by Insight-HXMT. Here we report similar properties found in Swift J1727.8–1613 from the joint...
We performed a long-term study of the Z-track X-ray binary source GX 17+2, using AstroSat and NICER observations from the year 2016 to 2020. The source spectra is well defined by combination of disk emission, blackbody emisison component and a Comptonized component. Since the factor responsible for such spectral evolution in Z-track sources remain uncertain, we investigated the variation of...
Polarized X-ray emission from weakly magnetized neutron stars provides key insights into the geometry of the innermost regions of the accretion flow. The results of the spectro-polarimetric analysis of GX 340+0 in both HB and NB, as well as of GX 349+2 in the NB, will be presented. Notably, the soft spectral component exhibits variation between the hard and soft states, while the Comptonized...
GX 339–4 is a low-mass X-ray binary often used as an archetype, showing typical source behaviors. The source undergoes a full outburst every 2-3 years, passing through all known accretion
states. The 2023-2024 outburst was monitored as part of a multiwavelength campaign, which
included X-ray observations by IXPE and NICER. We
used NICER data to analyze the spectral-timing properties of GX...
We report the results obtained from the analysis of XMM–Newton observations together with simultaneous NICER and NuSTAR observations of the ultraluminous X-ray source NGC 4190 ULX-1. Our goal is to constrain the structure of the accretion disk and the geometrical properties of the source, performing temporal and spectral analyses in the 0.4−30 keV energy range. The temporal analysis shows no...
