79 research outputs found
Synchrotron Self-Absorption Process in GRBs and the Isotropic Energy - Peak Energy Fundamental Relation
The existence of strong correlation between the peak luminosity (and/or
bolometric energetics) of Gamma Ray Bursts (GRB) is one of the most intrigue
problem of GRB physics. This correlation is not yet understood. Here we
demonstrate that this correlation can be explained in framework of synchrotron
self-absorption (SSA) mechanism of GRB prompt emission. We estimate the
magnetic field strength of the central engine at the level , where is the Lorentz factor of fireball.Comment: 5 page
Magnetic fields of active galaxy nuclei and cosmological models
We present the review of various methods of detection of magnetic field
strengths in the nearest regions of the active galaxy nuclei (AGN) which are
the high energetic machines. Original spectropolarimetric method developed in
the Pulkovo Observatory allows us to determine the magnitude and geometry of
the magnetic field in the region of the optical and more hard electromagnetic
radiation. The results of theoretical calculations are compared to the results
of spectropolarimetric observations of AGN. We used the method of determining
magnetic fields through the spectrum synchrotron radiation in the region of
synchrotron self-absorption. As the magnitude of magnetic field of the
extragalactic source depends very strongly on the angular size of extragalactic
source and therefore on the photometric distance the calculated magnetic field
magnitudes depends very strongly on the definite cosmological model. This
result allows us to present the new method for determination of the most
important cosmological parameters including dark matter and dark energy
parameters.Comment: 8 pages, 7 figure
Magnetic Fields of Nearby Active Galactic Nuclei and Correlation of the Highest-Energy Cosmic Rays with their Positions
The correlation between the pointing direction of ultra high energy cosmic
rays and AGN observed by the Pierre Auger Collaboration is explained in the
framework of acceleration process in AGN. This acceleration process is produced
by a rotating accretion disk around a black hole that is frozen-in magnetic
field. In a result the accretion disk is acting as a induction accelerator of
cosmic rays. We estimate the resulting magnetic field in the framework of the
magnetic coupling process. The results of our calculations allow to make the
conclusion that the Flat Spectrum Radio Quasars appear the effective cosmic
accelerators. We estimate also the attenuation of highest-energy cosmic rays in
a result of their interaction with ambient radiation field.Comment: 5 page
Photon-Axion-Like Particle Coupling Constant and Cosmological Observations
We estimated the photon-pseudoscalar particle mixing constant from the effect
of cosmological alignment and cosmological rotation of polarization plane of
distant QSOs. This effect is explained in terms of birefringent phenomenon due
to photon-pseudoscalar (axion-like) particle mixing in a cosmic magnetic field.
On the contrary, one can estimate the strength of the cosmic magnetic field
using the constraints on the photon-axion-like particle coupling constant from
the CAST experiment and from SNe Ia dimming effect. In a result, the lower
limit on the intergalactic () magnetic field appears at the
level of about G.Comment: 8 page
Constraining Recoiling Velocities of Black Holes Ejected by Gravitational Radiation in Galaxy Mergers
Recent general relativistic simulations have shown that the coalescence of
two spinning black holes (BH) can lead to recoiling speeds of the BH remnant of
up to thousands of km/s as a result of the gravitational radiation emission. It
is important that the accretion disc remains bound to ejected BH within the
region where the gas orbital velocity is larger than the ejection speed. We
considered the situation when the recoiling kick radius coincides with the
radius of the broad line region (BLR). We show that in this situation the
observed polarization data of accretion disk emission allow to determine the
value of the recoil velocity. We present the estimates of the kick velocity for
AGN with determined polarization data.Comment: 7 pages, 1 figures, 2 tables. Accepted for publication in
Astrophysics and Space Science
Intrinsic Origin Of Extreme-Scale Rotation Of Quasar Polarization Vectors
Extreme-scale alignment of quasar optical polarization vectors at
cosmological scales () is also characterized by the rotation of mean
position angle with per 1 Gpc. For
observing interval of the total rotation angle acquires the value . We suggest the possible explanation of the half of this rotation
as a consequence of physical transformation of initially vertical magnetic
field , directed along the normal to the surface of
accretion disk, into the horizontal (perpendicular to ) one. We found
asymptotical analytical expressions for axially averaged polarization degree
and mean position angle for various types of magnetized accretion
disks. We found also that during the evolution can be realized the case
where position angle rotates from
to zero. This rotation may occur during fairly great cosmological time
(corresponding to ). The part of rotation can be explained by a mechanism of alignment of
polarization vectors, say distribution of the part of quasars as a spiral in
the cosmic space with slow variation of rotation axis of corresponding
accretion disks. Both mechanisms are mutually related one with another.Comment: 7 page
Magnetic Fields of Black Holes and the Variability Plane
We estimated the magnetic field strength at the horizon radius of black
holes, that is derived by the magnetic coupling process and depended on the
black hole mass and the accretion rate . Our estimation is
based on the use of the fundamental variability plane for stellar mass black
holes, AGNs and QSOs. The typical values of magnetic field strength on the
black hole horizon are appeared at the level of G for stellar
mass black holes and G for the supermassive black holes. We
have obtained the relation between the intrinsic
polarization of the accretion disk radiation and the characteristic frequency
of the black hole X-ray variability.Comment: 4 page
Constraints on Spin of a Supermassive Black Hole in Quasars with Big Blue Bump
We determined the spin value of supermassive black hole (SMBH) in active
galactic nuclei (AGN) with investigated ultraviolet-to-optical spectral energy
distribution, presented in the sample of Shang et al. (2005). The estimates of
the spin values have been produced at the base of the standard geometrically
thin accretion disk model and with using the results of the polarimetric
observations. The polarimetric observations are very important for determining
the inclination angle of AGN disk. We presented the results of our
determinations of the radiation efficiency of the accretion flow and values of
the spins of SMBHs, that derives the coefficient of radiation efficiency. The
majority of SMBHs of AGNs from Shang et al. (2005) sample are to be the Kerr
black holes with the high spin value.Comment: 5 pages, 1 figur
The Black Hole Mass and Magnetic Field Correlation in AGN: Testing by Optical Polarimetry
We consider the integral light polarization from optically thick accretion
disks. Basic mechanism is the multiple light scattering on free electrons
(Milne's problem) in magnetized atmosphere. The Faraday rotation of the
polarization plane changes both the value of integral polarization degree
and the position angle . Besides, the characteristic spectra of these
values appear. We are testing the known relation between magnetic field of
black hole at the horizon and its mass , and the usual
power-law distribution inside the accretion disk. The formulae for
and depend on a number of parameters describing the particular
dependence of magnetic field in accretion disk (the index of power-law
distribution, the spin of the black hole, etc.). Comparison of our theoretical
values of and with observed polarization can help us to choice more
realistic values of parameters if the accretion disk mechanism gives the main
contribution to the observed integral polarization. The main content is
connected with estimation of validity of the relation between and
. We found for the AGN NGC 4258 that such procedure does not confirm
the mentioned correlation between magnetic field and mass of black hole.Comment: 7 page
Magnetic field and radius of innermost stable circular orbit near SMBH in AGNs
Magnetic fields in an accretion disk around the central black hole can modify
the position of the innermost stable circular orbit (ISCO) radius and produces
the difference for the classical Novikov-Thorne radius. We estimated the ISCO
magnetic field strength on the base of polarimetric observations of the
accretion disk radiation. This estimate can be obtained with taking into
account the effect of Faraday rotation of the polarization plane at the length
of the free path of photon between successive electron scattering events. In a
result we presented the new method for real estimation of the ISCO radius in
the accretion disk, i.e. in the nearest vicinity of a central black hole. Our
estimations confirmed the V.P. Frolov, A.A. Shoom and C. Tzounis (2014)
conclusion that magnetic field produces the effect in a result of which the
innermost stable circular orbit becomes closer to the horizon of a black hole.Comment: 7 page
- …