scholarly journals NuSTAR monitoring of MAXI J1348-630: evidence of high density disc reflection

2021 ◽  
Author(s):  
Sudip Chakraborty ◽  
Ajay Ratheesh ◽  
Sudip Bhattacharyya ◽  
John A Tomsick ◽  
Francesco Tombesi ◽  
...  
Keyword(s):  
Black Hole ◽  
Statistical Significance ◽  
High Density ◽  
X Ray ◽  
Soft State ◽  
Iron Abundance ◽  
Model Scheme ◽  
Best Fit ◽  
Very High ◽  
Reflection Models

Abstract We present the broadband spectral analysis of all the six hard, intermediate and soft state NuSTAR observations of the recently discovered transient black hole X-ray binary MAXI J1348-630 during its first outburst in 2019. We first model the data with a combination of a multi-colour disc and a relativistic blurred reflection, and, whenever needed, a distant reflection. We find that this simple model scheme is inadequate in explaining the spectra, resulting in a very high iron abundance. We, therefore, explore the possibility of reflection from a high-density disc. We use two different sets of models to describe the high-density disc reflection: relxill-based reflection models, and reflionx-based ones. The reflionx-based high-density disc reflection models bring down the iron abundance to around the solar value, while the density is found to be $10^{20.3-21.4} \rm cm^{-3}$. We also find evidence of a high-velocity outflow in the form of ∼7.3 keV absorption lines. The consistency between the best-fit parameters for different epochs and the statistical significance of the corresponding model indicates the existence of high-density disc reflection in MAXI J1348-630.

scholarly journals Thermal and radiation driving can produce observable disc winds in hard-state X-ray binaries

2020 ◽  
Vol 492 (4) ◽  
pp. 5271-5279 ◽  
Author(s):  
Nick Higginbottom ◽  
Christian Knigge ◽  
Stuart A Sim ◽  
Knox S Long ◽  
James H Matthews ◽  
...  
Keyword(s):  
Black Hole ◽  
Binary Systems ◽  
Velocity Structure ◽  
Spectral Energy ◽  
X Ray ◽  
Black Hole Binaries ◽  
Soft State ◽  
Before And After ◽  
Hard State ◽  
New Generation

ABSTRACT X-ray signatures of outflowing gas have been detected in several accreting black hole binaries, always in the soft state. A key question raised by these observations is whether these winds might also exist in the hard state. Here, we carry out the first full-frequency radiation hydrodynamic simulations of luminous (${L = 0.5 \, L_{\mathrm{\mathrm{ Edd}}}}$) black hole X-ray binary systems in both the hard and the soft state, with realistic spectral energy distributions (SEDs). Our simulations are designed to describe X-ray transients near the peak of their outburst, just before and after the hard-to-soft state transition. At these luminosities, it is essential to include radiation driving, and we include not only electron scattering, but also photoelectric and line interactions. We find powerful outflows with ${\dot{M}_{\mathrm{ wind}} \simeq 2 \, \dot{M}_{\mathrm{ acc}}}$ are driven by thermal and radiation pressure in both hard and soft states. The hard-state wind is significantly faster and carries approximately 20 times as much kinetic energy as the soft-state wind. However, in the hard state the wind is more ionized, and so weaker X-ray absorption lines are seen over a narrower range of viewing angles. Nevertheless, for inclinations ≳80°, blueshifted wind-formed Fe xxv and Fe xxvi features should be observable even in the hard state. Given that the data required to detect these lines currently exist for only a single system in a luminous hard state – the peculiar GRS 1915+105 – we urge the acquisition of new observations to test this prediction. The new generation of X-ray spectrometers should be able to resolve the velocity structure.

scholarly journals The soft state of the black hole transient source MAXI J1820+070: emission from the edge of the plunge region?

2020 ◽  
Vol 493 (4) ◽  
pp. 5389-5396 ◽  
Author(s):  
A C Fabian ◽  
D J Buisson ◽  
P Kosec ◽  
C S Reynolds ◽  
D R Wilkins ◽  
...  
Keyword(s):  
Black Hole ◽  
Photon Counting ◽  
Black Hole Mass ◽  
X Ray ◽  
Excess Emission ◽  
Transient Source ◽  
Stable Circular Orbit ◽  
Soft State ◽  
Galactic Black Hole ◽  
Innermost Stable Circular Orbit

ABSTRACT The Galactic black hole X-ray binary MAXI J1820+070 had a bright outburst in 2018 when it became the second brightest X-ray source in the sky. It was too bright for X-ray CCD instruments such as XMM–Newton and Chandra, but was well observed by photon-counting instruments such as Neutron star Inner Composition Explorer (NICER) and Nuclear Spectroscopic Telescope Array(NuSTAR). We report here on the discovery of an excess-emission component during the soft state. It is best modelled with a blackbody spectrum in addition to the regular disc emission, modelled as either diskbb or kerrbb. Its temperature varies from about 0.9 to 1.1 keV, which is about 30–80 per cent higher than the inner disc temperature of diskbb. Its flux varies between 4 and 12 per cent of the disc flux. Simulations of magnetized accretion discs have predicted the possibility of excess emission associated with a non-zero torque at the innermost stable circular orbit (ISCO) about the black hole, which, from other NuSTAR studies, lies at about 5 gravitational radii or about 60 km (for a black hole, mass is $8\, {\rm M}_{\odot }$). In this case, the emitting region at the ISCO has a width varying between 1.3 and 4.6 km and would encompass the start of the plunge region where matter begins to fall freely into the black hole.

scholarly journals The stringent upper limit on jet power in the persistent soft-state source 4U 1957+11

2020 ◽  
Vol 498 (1) ◽  
pp. L40-L45
Author(s):  
Thomas J Maccarone ◽  
Arlo Osler ◽  
James C A Miller-Jones ◽  
P Atri ◽  
David M Russell ◽  
...  
Keyword(s):  
Black Hole ◽  
Type I ◽  
X Ray ◽  
Upper Limit ◽  
Source Distance ◽  
Upper Limits ◽  
Soft State ◽  
Hard State ◽  
Comprehensive Search ◽  
Radio Power

ABSTRACT We present extremely deep upper limits on the radio emission from 4U 1957+11, an X-ray binary that is generally believed to be a persistently accreting black hole that is almost always in the soft state. We discuss a more comprehensive search for Type I bursts than in past work, revealing a stringent upper limit on the burst rate, bolstering the case for a black hole accretor. The lack of detection of this source at the 1.07 μJy/beam noise level indicates jet suppression that is stronger than expected even in the most extreme thin disc models for radio jet production – the radio power here is 1500–3700 times lower than the extrapolation of the hard state radio/X-ray correlation, with the uncertainties depending primarily on the poorly constrained source distance. We also discuss the location and velocity of the source and show that it must have either formed in the halo or with a strong asymmetric natal kick.

scholarly journals Mixed H/He bursts in SAX J1748.9–2021 during the spectral change of its 2015 outburst

2018 ◽  
Vol 620 ◽  
pp. A114 ◽  
Author(s):  
Z. Li ◽  
V. De Falco ◽  
M. Falanga ◽  
E. Bozzo ◽  
L. Kuiper ◽  
...  
Keyword(s):  
Plasma Temperature ◽  
Compact Object ◽  
Recurrence Time ◽  
Type I ◽  
Slab Geometry ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Best Fit ◽  
Spectral States

SAX J1748.9–2021 is a transiently accreting X-ray millisecond pulsar. It is also known as an X-ray burster source discovered by Beppo-SAX. We analyzed the persistent emission and type-I X-ray burst properties during its 2015 outburst. The source changed from hard to soft state within half day. We modeled the broadband spectra of the persistent emission in the (1–250) keV energy band for both spectral states using the quasi-simultaneous INTEGRAL and Swift data. The broadband spectra are well fitted by an absorbed thermal Componization model, COMPPS, in a slab geometry. The best-fits for the two states indicate significantly different plasma temperature of 18 and 5 keV and the Thomson optical depths of three and four, respectively. In total, 56 type-I X-ray bursts were observed during the 2015 outburst, of which 26 detected by INTEGRAL in the hard state, 25 by XMM-Newton in the soft state, and five by Swift in both states. As the object transited from the hard to the soft state, the recurrence time for X-ray bursts decreased from ≈2 to ≈1 h. The relation between the recurrence time, Δtrec, and the local mass accretion rate per unit area onto the compact object, ṁ, is fitted by a power-law model, and yielded as best fit at Δtrec ∼ ⟨ṁ⟩−1.02±0.03 using all X-ray bursts. In both cases, the observed recurrence times are consistent with the mixed hydrogen and helium bursts. We also discuss the effects of type-I X-ray bursts prior to the hard to soft transition.

scholarly journals OBSERVATIONS OF MICROQUASAR CANDIDATES WITH THE MAGIC TELESCOPE

2008 ◽  
Vol 17 (10) ◽  
pp. 1859-1866
Author(s):  
◽  
J. RICO
Keyword(s):  
Black Hole ◽  
Experimental Evidence ◽  
Energy Band ◽  
High Energy ◽  
Time Dependent ◽  
X Ray ◽  
Orbital Cycles ◽  
Very High Energy ◽  
Γ Ray ◽  
Very High

We report on the results from the observations in very high energy band (VHE, Eγ ≥ 100 GeV ) of the γ-ray binary LS I +61 303 and the black hole X-ray binary (BHXB) Cygnus X-1. LS I +61 303 was recently discovered at VHE by MAGIC1 and here we present the preliminary results from an extensive observation campaign, comprising 112 observation hours covering 4 orbital cycles, aiming at determining the time-dependent features of the VHE emission. Cygnus X-1 was observed for a total of 40 hours during 26 nights, spanning the period between June and November 2006. We report on the results of the searches for steady and variable γ-ray signals from Cygnus X-1, including the first experimental evidence for an intense flare, of duration between 1.5 and 24 hours.

scholarly journals A detailed study on the reflection component for the black hole candidate MAXI J1836−194

2020 ◽  
Vol 493 (2) ◽  
pp. 2178-2187
Author(s):  
Yanting Dong ◽  
Javier A García ◽  
Zhu Liu ◽  
Xueshan Zhao ◽  
Xueying Zheng ◽  
...  
Keyword(s):  
Black Hole ◽  
Spectral Analysis ◽  
Primary Source ◽  
Ionization State ◽  
X Ray ◽  
Black Hole Candidate ◽  
Reflection Model ◽  
Iron Abundance ◽  
Reflection Component ◽  
Ionization Gradient

ABSTRACT We present a detailed spectral analysis of the black hole candidate MAXI J1836−194. The source was caught in the intermediate state during its 2011 outburst by Suzaku and RXTE. We jointly fit the X-ray data from these two missions using the relxill model to study the reflection component, and a steep inner emissivity profile indicating a compact corona as the primary source is required in order to achieve a good fit. In addition, a reflection model with a lamp-post configuration (relxilllp), which is normally invoked to explain the steep emissivity profile, gives a worse fit and is excluded at 99 per cent confidence level compared to relxill. We also explore the effect of the ionization gradient on the emissivity profile by fitting the data with two relativistic reflection components, and it is found that the inner emissivity flattens. These results may indicate that the ionization state of the disc is not constant. All the models above require a supersolar iron abundance higher than ∼4.5. However, we find that the high-density version of reflionx can describe the same spectra even with solar iron abundance well. A moderate rotating black hole (a* = 0.84–0.94) is consistently obtained by our models, which is in agreement with previously reported values.

scholarly journals Disc and wind in black hole X-ray binary MAXI J1820+070 observed through polarized light during its 2018 outburst

2020 ◽  
Vol 496 (1) ◽  
pp. L96-L100
Author(s):  
Ilia A Kosenkov ◽  
Alexandra Veledina ◽  
Andrei V Berdyugin ◽  
Vadim Kravtsov ◽  
Vilppu Piirola ◽  
...  
Keyword(s):  
Black Hole ◽  
Polarized Light ◽  
Position Angle ◽  
Intrinsic Polarization ◽  
Data Set ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Low Mass ◽  
Optical Flux

ABSTRACT We describe the first complete polarimetric data set of the entire outburst of a low-mass black hole X-ray binary system and discuss the constraints for geometry and radiative mechanisms it imposes. During the decaying hard state, when the optical flux is dominated by the non-thermal component, the observed polarization is consistent with the interstellar values in all filters. During the soft state, the intrinsic polarization of the source is small, ∼0.15 per cent in B and V filters, and is likely produced in the irradiated disc. A much higher polarization, reaching ∼0.5 per cent in V and R filters, at a position angle of ∼25○ observed in the rising hard state coincides in time with the detection of winds in the system. This angle coincides with the position angle of the jet. The detected optical polarization is best explained by scattering of the non-thermal (hot flow or jet base) radiation in an equatorial wind.

scholarly journals Colors and patterns of black hole X-ray binary GX 339-4

2020 ◽  
Vol 638 ◽  
pp. A127
Author(s):  
Ilia A. Kosenkov ◽  
Alexandra Veledina ◽  
Valery F. Suleimanov ◽  
Juri Poutanen
Keyword(s):  
Black Hole ◽  
Accretion Disk ◽  
Near Infrared ◽  
Interstellar Extinction ◽  
State Transitions ◽  
Infrared Range ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Infrared Wavelengths

Black hole X-ray binaries show signs of nonthermal emission in the optical to near-infrared range. We analyzed optical to near-infrared SMARTS data on GX 339-4 over the 2002–2011 period. Using soft state data, we estimated the interstellar extinction toward the source and characteristic color temperatures of the accretion disk. We show that various spectral states of regular outbursts occupy similar regions on color-magnitude diagrams, and that transitions between the states proceed along the same tracks despite substantial differences in the morphology of the observed light curves. We determine the typical duration of hard-to-soft and soft-to-hard state transitions and the hard state at the decaying stage of the outburst to be one, two, and four weeks, respectively. We find that the failed outbursts cannot be easily distinguished from the regular outbursts at their early stages, but if the source reaches 16 mag in V band, it transits to the soft state. By subtracting the contribution of the accretion disk, we obtain spectra of the nonthermal component, which have constant, nearly flat shapes during the transitions between the hard and soft states. In contrast to the slowly evolving nonthermal component seen at optical and near-infrared wavelengths, the mid-infrared spectrum is strongly variable on short timescales and sometimes shows a prominent excess with a cutoff below 1014 Hz. We show that the radio to optical spectrum can be modeled using three components corresponding to the jet, hot flow, and irradiated accretion disk.

scholarly journals GRS 1758–258: RXTE Monitoring of a Rare Persistent Hard State Black Hole

10.14311/1480 ◽  
2011 ◽  
Vol 51 (6) ◽  
Author(s):  
M. Obst ◽  
K. Pottschmidt ◽  
A. Lohfink ◽  
J. Wilms ◽  
M. Böck ◽  
...  
Keyword(s):  
Black Hole ◽  
State Transitions ◽  
Spectral Evolution ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Long Term Behavior ◽  
X Ray Binaries ◽  
Black Hole Candidates

GRS 1758–258 is the least studied of the three persistent black hole X-ray binaries in our Galaxy. It is also one of only two known black hole candidates, including all black hole transients, which shows a decrease of its 3-10 keV flux when entering the thermally dominated soft state, rather than an increase.We present the spectral evolution of GRS 1758–258 from RXTE-PCA observations spanning a time of about 11 years from 1996 to 2007. During this time, seven dim soft states are detected. We also consider INTEGRAL monitoring observations of the source and compare the long-term behavior to that of the bright persistent black hole X-ray binary Cygnus X-1. We discuss the observed state transitions in the light of physical scenarios for black hole transitions.

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