scholarly journals Scaling of X-ray spectral properties of a black hole in the Seyfert 1 galaxy NGC7469

2018 ◽  
Vol 619 ◽  
pp. A21 ◽  
Author(s):  
Elena Seifina ◽  
Lev Titarchuk ◽  
Lyubov Ugolkova
Keyword(s):  
Black Hole ◽  
Spectral Properties ◽  
Observational Evidence ◽  
X Ray ◽  
Bulk Motion ◽  
Photon Index ◽  
Hard State ◽  
Mass Estimate ◽  
Ngc 4051 ◽  
Ngc 7469

We present our analysis of X-ray spectral properties observed from the Seyfert 1 galactic nucleus NGC 7469 using the Rossi X-ray Timing Explorer (RXTE) and Advanced Satellite for Cosmology and Astrophysics mission (ASCA) observations. We demonstrate strong observational evidence that NGC 7469 undergoes spectral transitions from the low hard state (LHS) to the intermediate state (IS) during these observations. The RXTE observations (1996–2009) show that the source was in the IS ∼75% of the time only ∼25% of the time in the LHS. The spectra of NGC 7469 are well fitted by the so-called bulk motion Comptonization (BMC) model for all spectral states. We have established the photon index (Γ) saturation level, Γsat = 2.1 ± 0.1, in the Γ versus mass accretion rate, Ṁ correlation. This Γ – Ṁ correlation allows us to estimate the black hole (BH) mass in NGC 7469 to be MBH ≥ 3 × 106 M⊙ assuming the distance to NGC 7469 of 70 Mpc. For this BH mass estimate, we use the scaling method taking Galactic BHs, GRO J1655–40, Cyg X–1, and an extragalactic BH source, NGC 4051 as reference sources. The Γ versus Ṁ correlation revealed in NGC 7469 is similar to those in a number of Galactic and extragalactic BHs and it clearly shows the correlation along with the strong Γ saturation at ≈2.1. This is robust observational evidence for the presence of a BH in NGC 7469. We also find that the seed (disk) photon temperatures are quite low, of the order of 140–200 eV, which are consistent with a high BH mass in NGC 7469 that is more than 3 × 106 solar masses.

scholarly journals Correlation of time lag and photon index in GX 339-4

2018 ◽  
Vol 614 ◽  
pp. L5 ◽  
Author(s):  
Nikolaos D. Kylafis ◽  
Pablo Reig
Keyword(s):  
Black Hole ◽  
Power Law ◽  
Time Lag ◽  
Radio Spectrum ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Photon Index ◽  
Hard State ◽  
Two Parameters ◽  
Soft Disk

Context. Black hole transients, as a class, exhibit during their outbursts a correlation between the time lag of hard photons with respect to softer ones and the photon index of the hard X-ray power law. The correlation is not very tight and therefore it is necessary to examine it source by source. Aims. The objective of the present work is to investigate in detail the correlation between the time lag and the photon index in GX 339-4, which is the best studied black hole transient. Methods. We have obtained RXTE energy spectra and light curves and have computed the photon index and the time lag of the 9–15 keV photons with respect to the 2–6 keV photons. The observations cover the first stages of the hard state, the pure hard state, and the hard-intermediate state. Results. We have found a tight correlation between time lag and photon index Γ in the hard and hard-intermediate states. At low Γ, the correlation is positive; it becomes negative at high Γ By assuming that the hard X-ray power-law index Γ is produced by inverse Compton scattering of soft disk photons in the jet, we have reproduced the entire correlation by varying two parameters in the jet: the radius of the jet at its base R0 and the Thomson optical depth along the jet τ∥. We have found that as the luminosity of the source increases, R0 initially increases and then decreases. This behavior is expected in the context of the Cosmic Battery. Conclusions. Our jet model nicely explains the correlation with reasonable values of the parameters R0 and τ∥ These parameters also correlate between themselves. As a further test of our model, we predict the break frequency in the radio spectrum as a function of the photon index during the rising part of an outburst.

scholarly journals Investigating state transition luminosities of Galactic black hole transients in the outburst decay

2019 ◽  
Vol 485 (2) ◽  
pp. 2744-2758 ◽  
Author(s):  
A Vahdat Motlagh ◽  
E Kalemci ◽  
T J Maccarone
Keyword(s):  
Black Hole ◽  
Power Law ◽  
Intermediate State ◽  
State Transition ◽  
Archival Data ◽  
Weighted Mean ◽  
X Ray ◽  
Galactic Black Hole ◽  
Photon Index ◽  
Hard State

Abstract We have performed a comprehensive spectral and timing analyses of Galactic black hole transients (GBHTs) during outburst decay in order to obtain the distribution of state transition luminosities. Using the archival data of the Rossi X-ray Timing Explorer (RXTE), we have calculated the weighted mean for state transition luminosities of 11 BH sources in 19 different outbursts and for disc and power law luminosities separately. We also produced histograms of these luminosities in terms of Eddington luminosity fraction (ELF) and fitted them with a Gaussian. Our results show the tightest clustering in bolometric power law luminosity with a mean logarithmic ELF of −1.70 ± 0.21 during the index transition (as the photon index starts to decrease towards the hard state). We obtained mean logarithmic ELF of −1.80 ± 0.25 during the transition to the hard state (as the photon index reaches the lowest value) and −1.50 ± 0.32 for disc-blackbody luminosity (DBB) during the transition to the hard-intermediate state (HIMS). We discussed the reasons for clustering and possible explanations for sources that show a transition luminosity significantly below or above the general trends.

scholarly journals A quantitative explanation of the type-B QPOs in GX 339–4

2020 ◽  
Vol 640 ◽  
pp. L16
Author(s):  
Nikolaos D. Kylafis ◽  
Pablo Reig ◽  
Iossif Papadakis
Keyword(s):  
Black Hole ◽  
Photon Number ◽  
Low Frequency ◽  
Polar Angle ◽  
Periodic Variation ◽  
X Rays ◽  
Type B ◽  
X Ray ◽  
Bulk Motion ◽  
Photon Index

Context. Type-B quasi periodic oscillations (QPOs) in black-hole X-ray binaries are a class of low-frequency QPOs that are observed in the soft intermediate state in the rising and the declining phases of an outburst. They are suspected to result from the precession of the jet that is ejected from the source. Aims. The objective of the present work is to investigate in detail the emissivity of the jet in hard X-rays and to see whether the type-B QPOs from GX 339−4, which is the best studied black-hole transient, can be explained quantitatively with a precessing jet. Methods. We used our simple jet model, which invokes Comptonization in the jet, and examined the angular dependence of the upscattered photons that emerge from the jet and their energy distribution, which is a power law. Results. Due to the elongation of the jet, assisted by the bulk motion of the electrons, the angular distribution of the emerging hard X-ray photons from the jet is not isotropic. More importantly, the photon-number spectral index, Γ, is an increasing function of the polar angle, θ, with respect to the axis of the jet. If the jet is fixed, then an observer at infinity sees the photon index, Γ, which corresponds to this specific observational direction. However, if the jet is precessing, then the observer sees a periodic variation of Γ with the precession period. Such a periodic variation of Γ has been observed in GX 339−4 and in this work, we reproduce it quantitatively, using our model. Conclusions. Our jet model nicely explains through quantitative means the type-B QPOs seen in GX 339−4 as originating from a precessing jet. The given model has previously explained several observed correlations thus far.

scholarly journals The structure and emission of an inner disk and a corona in the low/hard state

2012 ◽  
Vol 8 (S290) ◽  
pp. 299-300
Author(s):  
Erlin Qiao ◽  
Bifang Liu
Keyword(s):  
Black Hole ◽  
X Ray ◽  
Stable Circular Orbit ◽  
Photon Index ◽  
Hard State ◽  
Innermost Stable Circular Orbit ◽  
Inner Region ◽  
Hot Corona ◽  
X Ray Binaries ◽  
Disk Component

AbstractRecent observations reveal that a cool disk may survive in the innermost stable circular orbit (ISCO) for some black hole X-ray binaries in the low/hard state. The spectrum is characterized by a power law with a photon index Γ ~ 1.5-2.1 in the range of 2-10 keV and a weak disk component with temperature of ~ 0.2 keV. The formation of such a cool disk in the most inner region of black hole X-ray binaries at the low/hard state is investigated within the framework of disk accretion fed by condensation of hot corona. We also calculate the emergent spectra of the inner disk and corona. It's found that our model can very well explain the spectral features of GX 339-4 and Cyg X-1, in which the thin disk may exist at ISCO in the low/hard state.

scholarly journals X-ray properties of reverberation-mapped AGNs with super-Eddington accreting massive black holes

2019 ◽  
Vol 15 (S356) ◽  
pp. 143-143
Author(s):  
Jaya Maithil ◽  
Michael S. Brotherton ◽  
Bin Luo ◽  
Ohad Shemmer ◽  
Sarah C. Gallagher ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Accretion Rate ◽  
Time Lags ◽  
Black Hole Mass ◽  
Host Galaxies ◽  
Massive Black Holes ◽  
X Ray ◽  
Photon Index ◽  
The Impact

AbstractActive Galactic Nuclei (AGN) exhibit multi-wavelength properties that are representative of the underlying physical processes taking place in the vicinity of the accreting supermassive black hole. The black hole mass and the accretion rate are fundamental for understanding the growth of black holes, their evolution, and the impact on the host galaxies. Recent results on reverberation-mapped AGNs show that the highest accretion rate objects have systematic shorter time-lags. These super-Eddington accreting massive black holes (SEAMBHs) show BLR size 3-8 times smaller than predicted by the Radius-Luminosity (R-L) relationship. Hence, the single-epoch virial black hole mass estimates of highly accreting AGNs have an overestimation of a factor of 3-8 times. SEAMBHs likely have a slim accretion disk rather than a thin disk that is diagnostic in X-ray. I will present the extreme X-ray properties of a sample of dozen of SEAMBHs. They indeed have a steep hard X-ray photon index, Γ, and demonstrate a steeper power-law slope, ασx.

X-ray spectral and timing studies of black hole transients in the hard state at low luminosity

2012 ◽  
Author(s):  
John A. Tomsick ◽  
Kazutaka Yamaoka ◽  
Emrah Kalemci ◽  
Stéphane Corbel ◽  
Philip Kaaret ◽  
...  
Keyword(s):  
Black Hole ◽  
X Ray ◽  
Hard State

scholarly journals Magnetar X-ray emission mechanisms

2012 ◽  
Vol 8 (S291) ◽  
pp. 160-160
Author(s):  
Silvia Zane
Keyword(s):  
Spectral Analysis ◽  
Physical Interpretation ◽  
Spectral Properties ◽  
Gamma Ray ◽  
X Ray ◽  
Spectral Components ◽  
Self Consistent ◽  
Photon Index ◽  
Index 2 ◽  
Surface Fields

AbstractSoft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are peculiar X-ray sources which are believed to be magnetars: ultra-magnetized neutron stars which emission is dominated by surface fields (often in excess of 1E14 G, i.e. well above the QED threshold).Spectral analysis is an important tool in magnetar astrophysics since it can provide key information on the emission mechanisms. The first attempts at modelling the persistent (i.e. outside bursts) soft X-ray (¡10 keV) spectra of AXPs proved that a model consisting of a blackbody (kT 0.3-0.6 keV) plus a power-law (photon index 2-4) could successfully reproduce the observed emission. Moreover, INTEGRAL observations have shown that, while in quiescence, magnetars emit substantial persistent radiation also at higher energies, up to a few hundreds of keV. However, a convincing physical interpretation of the various spectral components is still missing.In this talk I will focus on the interpretation of magnetar spectral properties during quiescence. I will summarise the present status of the art and the currents attempts to model the broadband persistent emission of magnetars (from IR to hard Xrays) within a self consistent, physical scenario.

scholarly journals Energy and time-lag spectra of galactic black-hole X-ray sources in the low/hard state

2003 ◽  
Vol 403 (1) ◽  
pp. L15-L18 ◽  
Author(s):  
P. Reig ◽  
N. D. Kylafis ◽  
D. Giannios
Keyword(s):  
Black Hole ◽  
Time Lag ◽  
X Ray ◽  
Galactic Black Hole ◽  
Hard State

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.

Sign in / Sign up

Export Citation Format

Share Document