Multiwavelength Monitoring of the Narrow‐Line Seyfert 1 Galaxy Arakelian 564. I.ASCAObservations and the Variability of the X‐Ray Spectral Components

2001 ◽  
Vol 561 (1) ◽  
pp. 131-145 ◽  
Author(s):  
T. J. Turner ◽  
P. Romano ◽  
I. M. George ◽  
R. Edelson ◽  
S. J. Collier ◽  
...  
Keyword(s):  
Narrow Line ◽  
X Ray ◽  
Spectral Components

Formalism for the determination of intermediate stress gradients using X-ray diffraction

2009 ◽  
Vol 42 (2) ◽  
pp. 192-197 ◽  
Author(s):  
Thomas Gnäupel-Herold
Keyword(s):  
Lattice Strain ◽  
Narrow Line ◽  
X Ray Diffraction ◽  
Beam Spot ◽  
Strain Measurements ◽  
One Dimensional ◽  
X Ray ◽  
Stress Gradients ◽  
Shaped Beam

A method is outlined that allows the determination of one-dimensional stress gradients at length scales greater than 0.2 mm. By using standard four-circle X-ray diffractometer equipment and simple aperture components, length resolutions down to 0.05 mm in one direction can be achieved through constant orientation of a narrow, line-shaped beam spot. Angle calculations are given for the adjustment of goniometer angles, and for the effective azimuth and tilt of the scattering vector for general angle settings in a four-circle goniometer. The latter is necessary for the computation of stresses from lattice strain measurements.

scholarly journals Independent Estimation of Black Hole Mass for the γ-ray-detected Archetypal Narrow-line Seyfert 1 Galaxy 1H 0323+342 from X-Ray Variability

2018 ◽  
Vol 866 (1) ◽  
pp. 69 ◽  
Author(s):  
Hai-Wu Pan ◽  
Weimin Yuan ◽  
Su Yao ◽  
S. Komossa ◽  
Chichuan Jin
Keyword(s):  
Black Hole ◽  
Narrow Line ◽  
Black Hole Mass ◽  
X Ray ◽  
Γ Ray

scholarly journals An Emission Line in the Hard X-Ray Spectrum of Hercules X-1: Quantized Cyclotron Emission from the Neutron Star

1977 ◽  
Vol 43 ◽  
pp. 34-34
Author(s):  
W. Pietsch ◽  
C. Reppin ◽  
R. Staubert ◽  
J. Truemper ◽  
W. Voges ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Second Harmonic ◽  
Narrow Line ◽  
Electron Cyclotron Emission ◽  
Polar Cap ◽  
Astrophysical Application ◽  
X Ray ◽  
Cyclotron Emission

A four hour balloon observation of HERC X-l during the 'On-state' in the 35 day cycle was performed on May 3rd, 1976. The 1.24 second pulsations show a pulsed fraction of 58 ± 8% in the 18-31 KeV interval. A pulsed flux (1.24 sec) was discovered in the 31-88 KeV interval with a pulsed fraction of 51 ± 14%. The spectrum of the pulsed flux can be represented up to 50 KeV by an exponential distribution with KT approximately 8 KeV. At approximately 58 KeV a strong and narrow line feature occurs which we interpret as electron cyclotron emission (ΔN = 1 Landau transition) from the polar cap plasma of the rotating neutron star. The corresponding magnetic field strength is approximately 5 x 1012 Gauss, neglecting gravitational red shift. There is evidence for a second harmonic at approximately 110 KeV (ΔN = 2 ).The astrophysical application of this discovery will be discussed in some detail.

A Rapid X‐Ray Flare in the Radio‐loud Narrow‐Line Quasar PKS 0558−504

2001 ◽  
Vol 554 (1) ◽  
pp. 233-239 ◽  
Author(s):  
T. G. Wang ◽  
M. Matsuoka ◽  
H. Kubo ◽  
T. Mihara ◽  
H. Negoro
Keyword(s):  
Narrow Line ◽  
X Ray

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 Evidence for an emerging disc wind and collimated outflow during an X-ray flare in the narrow-line Seyfert 1 galaxy Mrk 335

2019 ◽  
Vol 484 (3) ◽  
pp. 4287-4297 ◽  
Author(s):  
L C Gallo ◽  
A G Gonzalez ◽  
S G H Waddell ◽  
H J S Ehler ◽  
D R Wilkins ◽  
...  
Keyword(s):  
Narrow Line ◽  
X Ray

scholarly journals ASCA Observations of Narrow-Line Seyfert 1 Galaxies

1997 ◽  
Vol 159 ◽  
pp. 40-43 ◽  
Author(s):  
K. Hayashida
Keyword(s):  
Black Hole ◽  
Narrow Line ◽  
Black Hole Mass ◽  
Central Black Hole ◽  
X Ray ◽  
Eddington Limit

AbstractASCA observations of four narrow-line Seyfert 1 galaxies are presented. Among the four sources, two show X-ray spectra consisting of soft and hard components. Rapid X-ray variability is observed in all four sources. We estimate the central black-hole mass of these sources and find indications that the apparent luminosities exceed the Eddington limit under some assumptions.

scholarly journals X-Ray Observations of GRS 1915+105

1997 ◽  
Vol 163 ◽  
pp. 709-710 ◽  
Author(s):  
J. Greiner ◽  
B.A. Harmon ◽  
W.S. Paciesas ◽  
E.H. Morgan ◽  
R.A. Remillard
Keyword(s):  
Power Law ◽  
Count Rate ◽  
Monitoring Data ◽  
Detector Response ◽  
X Ray ◽  
Spectral Fitting ◽  
Spectral Components ◽  
Best Fit ◽  
Intensity Evolution ◽  
Thermal Bremsstrahlung

After the discovery of GRS 1915+105 (Castro-Tirado et al. 1992) we obtained pointed ROSAT observations every six months (12 until now). The flux in the ROSAT (0.1–2.4 keV) band is strikingly different from the simultaneous BATSE (25–50 keV) flux which was obtained by integrating the best fit power law (Fig. 1). Motivated by the different intensity evolution in the soft and hard X-ray band we have selected BATSE monitoring data collected simultaneously to ROSATdata and performed joint spectral fitting with XSPEC. As a result, we never got an acceptable fit (see Fig. 2): The BATSE power law (upper dotted line) is too steep to match the ROSAT band, and even allowing for an increased absorbing column (lower dotted line) does not solve the problem. Alternatively, neither a thermal bremsstrahlung fit (solid line) nor a power law fit (lower dash-dot line) to the ROSAT data match the BATSE flux. The upper dash-dot line is a -2.5 powerlaw which would match the BATSE data while giving too much 1–2 keV emission. A similar, but less stringent result is obtained when folding the best fit BATSE power law models with the HRI detector response to compare the expected count rate with the observed one. We therefore conclude that the spectrum during all simultaneous ROSAT/BATSE observations seemingly consists of two different spectral components.

scholarly journals Gamma-ray-emitting narrow-line Seyfert 1 galaxies: the Swift view

2020 ◽  
Vol 496 (2) ◽  
pp. 2213-2229 ◽  
Author(s):  
F D’Ammando
Keyword(s):  
Gamma Ray ◽  
Thermal Emission ◽  
Optical Emission ◽  
X Rays ◽  
Narrow Line ◽  
X Ray ◽  
Relativistic Jet ◽  
Photon Index ◽  
Γ Ray ◽  
Lower Variability

ABSTRACT We report the analysis of all Swift observations available up to 2019 April of γ-ray-emitting narrow-line Seyfert 1 galaxies (NLSy1). The distribution of X-ray luminosities (and fluxes) indicates that the jet radiation significantly contributes to their X-ray emission, with Doppler boosting making values higher than other radio-loud NLSy1. The 0.3–10 keV photon indices are on average harder with respect to radio-quiet and radio-loud NLSy1, confirming a dominant jet contribution in X-rays. However, the lower variability amplitude with respect to blazars and the softening of the spectrum in some periods suggests that also the corona radiation contributes to the X-ray emission. In optical and ultraviolet (UV) significant flux changes have been observed on daily, weekly, and monthly time-scale, providing a clear indication of the significant contribution of the jet radiation in this part of spectrum. A strong correlation between X-ray, UV, and optical emission and simultaneous flux variations have been observed in 1H 0323+342, SBS 0846+513, PMN J0948+0022 as expected in case the jet radiation is the dominant mechanism. Correlated multiband variability favours the jet-dominated scenario also in FBQS J1644+2619 and PKS 2004−447. The summed X-ray Telescope spectra of 1H 0323+342, SBS 0846+513, PMN J0948+0022, and FBQS J1644+2619 are well fitted by a broken power law with a break around 2 keV. The spectrum above 2 keV is dominated by the non-thermal emission from a beamed relativistic jet, as suggested by the hard photon index. A Seyfert-like feature like the soft X-ray excess has been observed below 2 keV, making these γ-ray-emitting NLSy1 different from typical blazars.

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