A relativistic funnel scattering model with variable bulk velocity reproduces the ~23% hard-state and ~12% soft-state polarization in Cygnus X-3 at low inclination using half-opening angles of 13-16 degrees.
Broad-band gamma-ray and X-ray spectra of NGC 4151 and their implications for physical processes and geometry
10 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
We study gamma-ray observations of NGC 4151 by GRO/OSSE contemporaneous with X-ray observations by ROSAT and Ginga in 1991 June and with ASCA in 1993 May. The spectra are well modeled by thermal Comptonization and a dual neutral absorber. We also find, for the first time for NGC 4151, a Compton-reflection spectral component in the Ginga/OSSE data. The OSSE spectra of those and other observations of NGC 4151 are statistically undistinguishable from the average OSSE spectrum of radio-quiet Seyfert 1s. NGC 4151 observed in 1991 and 1993 has the intrinsic X-ray/gamma-ray spectrum typical for Seyfert 1s, and the main property distinguishing it from other Seyfert 1s is a large absorbing column of $\sim 10^{23}$ cm$^{-2}$. We find no evidence for a strong, broad and redshifted, Fe K$\alpha$ line component in the ASCA spectrum of 1993 May. On the other hand, we confirm previous studies in that archival X-ray data do imply strong intrinsic X-ray variability and hardness of the intrinsic spectrum in low X-ray states. An observed softening of the intrinsic X-ray spectrum with the increasing flux implies variability in gamma-rays weaker than in X-rays, which agrees with the 100 keV flux changing only within a factor of 2 in archival OSSE and Granat/SIGMA observations. The relative hardness of the intrinsic X-ray spectrum rules out the homogeneous hot corona/cold disk model for this source. Instead, the hot plasma has to subtend a small solid angle as seen from the source of UV radiation. If the hot plasma is purely thermal, it consists of electrons rather than $e^+e^-$ pairs. On the other hand, the plasma can be pair-dominated if a small fraction of the power is nonthermal.
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Joint NICER+IXPE pulse-profile modeling of SRGA J144459.2-604207 favors large neutron-star mass and radius with two independent hotspots but shows strong sensitivity to joint-analysis methodology.
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citing papers explorer
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Relativistic Scattering in the Funnel of Cygnus X-3
A relativistic funnel scattering model with variable bulk velocity reproduces the ~23% hard-state and ~12% soft-state polarization in Cygnus X-3 at low inclination using half-opening angles of 13-16 degrees.
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On the assessment of the disk truncation and detection of type-II bursts from the accreting millisecond X-ray Pulsar IGR J17062-6143
Spectral fitting of 2022 observations indicates the disk reaches 7-17 R_g from the neutron star at low inclination, with first reported type-II bursts attributed to magnetospheric gating.
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Photon Escape from Slab Thomson Media: A Scattering-order-resolved Recursive Formalism for Comptonization Applications
A two-component recursion solves scattering-order-resolved escape in Thomson slabs exactly, yielding ⟨N⟩=2τ for Lambert injection and a universal high-order angular distribution.
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Pulse profile modelling of the 2024 outburst of the accreting millisecond pulsar SRGA J144459.2-604207
Joint NICER+IXPE pulse-profile modeling of SRGA J144459.2-604207 favors large neutron-star mass and radius with two independent hotspots but shows strong sensitivity to joint-analysis methodology.
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A bright flare in the obscured state of GRS 1915+105 as seen by NICER and Swift
A bright flare in GRS 1915+105's obscured state arises from enhanced intrinsic emission plus reduced obscuration, with stratified absorber-reflector geometry consistent with re-illumination after a failed disk wind and a delayed radio flare.
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Dense, multi-phase accretion disk atmosphere in the low-luminosity state of black hole transientV4641 Sgr
RGS spectra of V4641 Sgr reveal narrow N and O lines from a dense, multi-phase, photoionized disk atmosphere with log ξ ≈ 3.1 and 0.36 and velocities 540-720 km/s.
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The X-ray-to-UV relation does not evolve in homogeneous quasar samples
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