scholarly journals The core dominance parameter for gamma-ray loud blazars

2014 ◽  
Vol 10 (S313) ◽  
pp. 83-84
Author(s):  
Z. Y. Pei ◽  
J. H. Fan ◽  
Y. Liu ◽  
H. J. Xie ◽  
Y. Gao ◽  
...  
Keyword(s):  
Gamma Ray ◽  
The Core ◽  
Parent Distribution ◽  
Variability Index ◽  
Γ Ray ◽  
To Come

AbstractIn this work, we compiled 604 blazars with available core-dominance parameter, out of which 149 blazars are known to have γ-ray emissions. We compared the logR between the 149 Fermi-detected blazars (FDB) and the rest non-Fermi-detected blazars (non-FDB), and found that the average values are < logR > = 1.12 ± 0.88 for FDBs and < logR > = 0.05 ± 0.94 for non-FDBs. A K-S test shows that the probability for the distributions of FDB and non-FDB to come from the same parent distribution is P = 2.38 × 10−7. We also investigated the correlation between the core-dominance parameters and the γ-ray emission variability index (VI) for 125 FDBs (45 BLs and 79 FSRQs), and found that there is a tendency for VI to increase with the core-dominance parameter for 79 FSRQs, but there is no such tendency for 46 BLs.

scholarly journals Radio VLBA polarization and multiband monitoring of the high-redshift quasar S5 0836 + 710 during a high-activity period

2019 ◽  
Vol 491 (1) ◽  
pp. 858-873 ◽  
Author(s):  
M Orienti ◽  
F D’Ammando ◽  
M Giroletti ◽  
D Dallacasa ◽  
G Giovannini ◽  
...  
Keyword(s):  
High Activity ◽  
Gamma Ray ◽  
High Redshift ◽  
Activity Period ◽  
X Rays ◽  
Large Area ◽  
The Core ◽  
Rotation Measure ◽  
Spectrum Radio ◽  
Γ Ray

ABSTRACT We report on results of a multiband monitoring campaign from radio to γ-rays of the high-redshift flat spectrum radio quasar S5 0836 + 710 during a high-activity period detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. Two major flares were detected, in 2015 August and November. In both episodes, the apparent isotropic γ-ray luminosity exceeds 1050 erg s−1, with a doubling time-scale of about 3 h. The high γ-ray activity may be related to a superluminal knot that emerged from the core in 2015 April at the peak of the radio activity and is moving downstream along the jet. The low variability observed in X-rays may indicate that X-ray emission is produced by the low-energy tail of the same electron population that produces the γ-ray emission. The analysis of full-polarization pc-scale radio observations suggests the presence of a limb-brightened polarization structure at about 1 mas from the core in which a rotation measure gradient with a sign change is observed transverse to the jet direction. These characteristics are consistent with a scenario in which Faraday rotation is produced by a sheath of thermal electrons with a toroidal magnetic field surrounding the emitting jet.

scholarly journals The Correlation between the Gamma-Ray Luminosity and the Core-Dominance Parameters for a Fermi Blazar Sample

2013 ◽  
Vol 9 (S304) ◽  
pp. 157-158
Author(s):  
J. H. Fan ◽  
J. H. Yang ◽  
D. X. Wu ◽  
S. H. Li ◽  
Y. Liu ◽  
...  
Keyword(s):  
Linear Correlation ◽  
Gamma Ray ◽  
The Other ◽  
Radio Emissions ◽  
The Core ◽  
Extended Radio ◽  
Γ Ray

AbstractIn this work, we investigated the correlation between the γ-ray luminosity, logLγ and the core-dominance parameter, log (1+R), for a sample of 124 Fermi blazars with available core and extended radio emissions. Our analysis shows that there is no correlation between the γ-ray luminosity, log Lγ and the core-dominance parameter, log (1+R). However, there is a closely linear correlation between log Lγ − log LExt and log (1+R), log Lγ−log LExt = (0.95 ± 0.08) log (1+R) + (2.72 ± 0.11), for the whole sample. The result suggests that the γ-ray emissions are composed of two components, one is beamed, the other is unbeamed.

scholarly journals Very Long Baseline Interferometry Observations of the Proposed Radio Counterpart of an EGRET Source

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1516
Author(s):  
Patrik Milán Veres ◽  
Krisztina Éva Gabányi ◽  
Sándor Frey
Keyword(s):  
Very Long Baseline Interferometry ◽  
Gamma Ray ◽  
Interferometric Imaging ◽  
High Brightness ◽  
The Core ◽  
Long Baseline ◽  
Superluminal Motion ◽  
Γ Ray ◽  
Previous Claim ◽  
Jet Structure

We present high-resolution radio interferometric imaging observations of the radio source NVSS J182659+343113 (hereafter J1826+3431), the proposed radio counterpart of the γ-ray source, 3EG J1824+3441 detected by the Energetic Gamma Ray Experiment Telescope (EGRET) on board the Compton Gamma Ray Observatory satellite. We analyzed eight epochs of archival multi-frequency very long baseline interferometry data. We imaged the asymmetric core–jet structure of the source, and detected apparent superluminal motion in the jet. At the highest observing frequency, 15.3 GHz, the core shows high brightness temperature indicating Doppler boosting. Additionally, the radio features undergo substantial flux density variability. These findings strengthen the previous claim of the association of the blazar J1826+3431 with the possible γ-ray source, 3EG J1824+3441.

scholarly journals Gamma-Ray Imaging of the Galactic Center Region

1989 ◽  
Vol 136 ◽  
pp. 581-585
Author(s):  
W. R. Cook ◽  
D. M. Palmer ◽  
T. A. Prince ◽  
S. M. Schindler ◽  
C. H. Starr ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Galactic Center ◽  
Coded Aperture ◽  
Center Region ◽  
Gamma Ray Imaging ◽  
The Galaxy ◽  
Γ Ray ◽  
Luminous Objects

The Caltech imaging γ-ray telescope was launched by balloon from Alice Springs, NT, Australia and performed observations of the galactic center during the period 12.62 to 13.00 April 1988 UT. The first coded-aperture images of the galactic center region at energies above 30 keV show a single strong γ-ray source which is located 0.7±0.1° from the galactic nucleus and is tentatively identified as 1E1740.7-2942. If the source is at the distance of the galactic center, it is one of the most luminous objects in the galaxy at energies from 35 to 200 keV.

Marc B. Shapiro. The Limits of Orthodox Theology: Maimonides' Thirteen Principles Reappraised. The Littman Library of Jewish Civilization. Oxford: Oxford University Press, 2004. 221 pp.

AJS Review ◽  
2005 ◽  
Vol 29 (1) ◽  
pp. 169-171
Author(s):  
Gidon Rothstein
Keyword(s):  
Oxford University ◽  
The Core ◽  
The World ◽  
Orthodox Theology ◽  
Contemporary Writers ◽  
To Come ◽  
Contemporary Context ◽  
Oxford University Press

Marc Shapiro puts an explicit contemporary context on this remarkable collection of sources that disagreed with one part or other of Maimonides' Thirteen Principles—the beliefs Maimonides asserted were absolutely necessary to be considered a believing Jew and to attain the World to Come. By showing the extent to which past authors disagreed with those Principles, Shapiro seeks to debunk assertions by contemporary writers that place those Principles at the core of Orthodox belief.

The Receding Animal: Theorizing Anxiety and Attachment in Psychoanalysis from Freud to Imre Hermann

2016 ◽  
Vol 29 (1) ◽  
pp. 55-76 ◽  
Author(s):  
Lydia Marinelli ◽  
Andreas Mayer
Keyword(s):  
Oedipus Complex ◽  
Death Instinct ◽  
Case Histories ◽  
The Core ◽  
The Status ◽  
Animal Phobias ◽  
Indirect Observation ◽  
To Come ◽  
Wolf Man ◽  
Little Hans

ArgumentAnimals played an important role in the formation of psychoanalysis as a theoretical and therapeutic enterprise. They are at the core of texts such as Freud's famous case histories of Little Hans, the Rat Man, or the Wolf Man. The infantile anxiety triggered by animals provided the essential link between the psychology of individual neuroses and the ambivalent status of the “totem” animal in so-called primitive societies in Freud's attempt to construct an anthropological basis for the Oedipus complex in Totem and Taboo. In the following, we attempt to track the status of animals as objects of indirect observation as they appear in Freud's classical texts, and in later revisionist accounts such as Otto Rank's Trauma of Birth and Imre Hermann's work on the clinging instinct. In the 1920s and 1930s, the Freudian conception of patients' animal phobias is substantially revised within Hermann's original psychoanalytic theory of instincts which draws heavily upon ethological observations of primates. Although such a reformulation remains grounded in the idea of “archaic” animal models for human development, it allows to a certain extent to empiricize the speculative elements of Freud's later instinct theory (notably the death instinct) and to come to a more embodied account of psychoanalytic practice.

scholarly journals Molecular Clouds Observed by the EGRET Gamma-Ray Telescope

1997 ◽  
Vol 170 ◽  
pp. 22-24 ◽  
Author(s):  
Seth. W. Digel ◽  
Stanley D. Hunter ◽  
Reshmi Mukherjee ◽  
Eugéne J. de Geus ◽  
Isabelle A. Grenier ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Molecular Clouds ◽  
Gamma Ray ◽  
Angular Resolution ◽  
Cosmic Ray ◽  
High Energy ◽  
Background Rejection ◽  
Γ Rays ◽  
Γ Ray ◽  
Production Mechanisms

EGRET, the high-energy γ-ray telescope on the Compton Gamma-Ray Observatory, has the sensitivity, angular resolution, and background rejection necessary to study diffuse γ-ray emission from the interstellar medium (ISM). High-energy γ rays produced in cosmic-ray (CR) interactions in the ISM can be used to determine the CR density and calibrate the CO line as a tracer of molecular mass. Dominant production mechanisms for γ rays of energies ∼30 MeV–30 GeV are the decay of pions produced in collisions of CR protons with ambient matter and Bremsstrahlung scattering of CR electrons.

scholarly journals Luminous supernovae associated with ultra-long gamma-ray bursts from hydrogen-free progenitors extended by pulsational pair-instability

2020 ◽  
Vol 641 ◽  
pp. L10
Author(s):  
Takashi J. Moriya ◽  
Pablo Marchant ◽  
Sergei I. Blinnikov
Keyword(s):  
Light Curve ◽  
Energy Input ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Core Collapse ◽  
Decay Energy ◽  
Slow Cooling ◽  
Gamma Ray Burst ◽  
The Core ◽  
Optical Light Curve

We show that the luminous supernovae associated with ultra-long gamma-ray bursts can be related to the slow cooling from the explosions of hydrogen-free progenitors that are extended by pulsational pair-instability. We have recently shown that some rapidly-rotating hydrogen-free gamma-ray burst progenitors that experience pulsational pair-instability can keep an extended structure caused by pulsational pair-instability until the core collapse. These types of progenitors have large radii exceeding 10 R⊙ and they sometimes reach beyond 1000 R⊙ at the time of the core collapse. They are, therefore, promising progenitors of ultra-long gamma-ray bursts. Here, we perform light-curve modeling of the explosions of one extended hydrogen-free progenitor with a radius of 1962 R⊙. The progenitor mass is 50 M⊙ and 5 M⊙ exists in the extended envelope. We use the one-dimensional radiation hydrodynamics code STELLA in which the explosions are initiated artificially by setting given explosion energy and 56Ni mass. Thanks to the large progenitor radius, the ejecta experience slow cooling after the shock breakout and they become rapidly evolving (≲10 days), luminous (≳1043 erg s−1) supernovae in the optical even without energy input from the 56Ni nuclear decay when the explosion energy is more than 1052 erg. The 56Ni decay energy input can affect the light curves after the optical light-curve peak and make the light-curve decay slowly when the 56Ni mass is around 1 M⊙. They also have a fast photospheric velocity above 10 000 km s−1 and a hot photospheric temperature above 10 000 K at around the peak luminosity. We find that the rapid rise and luminous peak found in the optical light curve of SN 2011kl, which is associated with the ultra-long gamma-ray burst GRB 111209A, can be explained as the cooling phase of the extended progenitor. The subsequent slow light-curve decline can be related to the 56Ni decay energy input. The ultra-long gamma-ray burst progenitors we proposed recently can explain both the ultra-long gamma-ray burst duration and the accompanying supernova properties. When the gamma-ray burst jet is off-axis or choked, the luminous supernovae could be observed as fast blue optical transients without accompanying gamma-ray bursts.

scholarly journals Fermi-LAT and WMAP observations of the supernova remnant Puppis A

2013 ◽  
Vol 9 (S296) ◽  
pp. 295-299
Author(s):  
Marie-Hélène Grondin ◽  
John W. Hewitt ◽  
Marianne Lemoine-Goumard ◽  
Thierry Reposeur ◽  
Keyword(s):  
Supernova Remnants ◽  
Supernova Remnant ◽  
Gamma Ray ◽  
High Energy ◽  
Radio Spectrum ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Large Area ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Γ Ray

AbstractThe supernova remnant (SNR) Puppis A (aka G260.4-3.4) is a middle-aged supernova remnant, which displays increasing X-ray surface brightness from West to East corresponding to an increasing density of the ambient interstellar medium at the Eastern and Northern shell. The dense IR photon field and the high ambient density around the remnant make it an ideal case to study in γ-rays. Gamma-ray studies based on three years of observations with the Large Area Telescope (LAT) aboard Fermi have revealed the high energy gamma-ray emission from SNR Puppis A. The γ-ray emission from the remnant is spatially extended, and nicely matches the radio and X-ray morphologies. Its γ-ray spectrum is well described by a simple power law with an index of ~2.1, and it is among the faintest supernova remnants yet detected at GeV energies. To constrain the relativistic electron population, seven years of Wilkinson Microwave Anisotropy Probe (WMAP) data were also analyzed, and enabled to extend the radio spectrum up to 93 GHz. The results obtained in the radio and γ-ray domains are described in detail, as well as the possible origins of the high energy γ-ray emission (Bremsstrahlung, Inverse Compton scattering by electrons or decay of neutral pions produced by proton interactions).

Effect of γ-ray irradiation on performance of LiNbO(3)-based piezoelectric vibration sensors

2021 ◽  
Author(s):  
Huifen Wei ◽  
Wenping Geng ◽  
Kaixi Bi ◽  
Tao Li ◽  
Xiangmeng Li ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Extreme Environments ◽  
Theoretical Work ◽  
High Dose ◽  
Mems Devices ◽  
Micro Electro Mechanical Systems ◽  
Vibration Sensors ◽  
Irradiation Dosage ◽  
Gamma Ray Irradiation ◽  
Γ Ray

Abstract LiNbO3 (LN)-based micro-electro-mechanical systems (MEMS) vibration sensors exhibit giant prospection in extreme environments, where exist a great amount of irradiation. However, to the best of our knowledge, it is still unknown whether the irradiation affects the performance of LN-based piezoelectric MEMS sensors. Based on this consideration, it is necessary to model the irradiation environment to investigate the effect of high dosage irradiation on LN-based vibration sensors. Firstly, the theoretical work is done to study the Compton Effect on the Gamma-ray irradiation with Co-60 source. After irradiation, X-ray diffraction (XRD) characterization was performed to verify the effect of irradiation on the crystalline of LN thin film. Meanwhile, the performances of output voltages on the five MEMS devices under various dosage of irradiation are compared. As a result, a neglected shift of 0.02 degrees was observed from the XRD image only under maximum irradiation dosage of 100 Mrad(Si). Moreover, the output voltages of cantilever-beam vibration sensors decrease by 3.1%. Therefore, it is verified that the γ-ray irradiation has very little influence on the LN-based MEMS vibration sensors, which have great attraction on the materials and sensors under high-dose irradiation.

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