Search for cosmic gamma radiation with a vidicon spark chamber

1968 ◽  
Vol 46 (10) ◽  
pp. S427-S432 ◽  
Author(s):  
G. G. Fazio ◽  
H. F. Helmken ◽  
S. J. Cavrak Jr. ◽  
D. R. Hearn
Keyword(s):  
Energy Spectrum ◽  
Solar Flare ◽  
Gamma Radiation ◽  
High Altitude ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Upper Limit ◽  
Flux Formula ◽  
The Crab Nebula

A vidicon spark chamber flown in a high-altitude balloon has been used to search for primary gamma radiation (E > 100 MeV). No celestial gamma-ray source was detected. The new upper limit to the flux from the Crab nebula was found to be 3.1 × 10−5 cm−2 s−1, and the flux from the quiet sun to be [Formula: see text]. A solar flare (type 2) also occurred during the flight, of flux [Formula: see text], which is also a new upper limit. The gamma-ray background flux and energy spectrum at 4 g cm−2 altitude were measured.

scholarly journals Recent Results on the Search for 1011 eV Gamma Rays from the Crab Nebula

1971 ◽  
Vol 46 ◽  
pp. 65-67
Author(s):  
G. G. Fazio ◽  
H. F. Helmken ◽  
G. H. Rieke ◽  
T. C. Weekes
Keyword(s):  
Magnetic Field ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Cosmic Ray ◽  
Air Showers ◽  
Upper Limit ◽  
The Crab Nebula ◽  
Cerenkov Light ◽  
Significant Flux

The detection of Čerenkov light emitted by cosmic-ray air showers was used to search for cosmic gamma rays from the Crab Nebula. By use of the 10-m optical reflector at Mt. Hopkins, Arizona, the Crab Nebula was observed during the winter of 1969–1970 for approximately 112 hours, which was a significant increase in exposure time over previous experiments. Above a gamma-ray energy of 2.2 × 1011 eV, no significant flux was detected, resulting in an upper limit to the flux of 8.1 × 10-11 photon/cm2 sec. In the synchrotron-Compton-scattering model of gamma-ray production in the Crab Nebula, this limit on the flux indicates the average magnetic field in the nebula must be greater than 3 × 10-4 G.

scholarly journals High-Energy Discrete Sources

1973 ◽  
Vol 55 ◽  
pp. 303-323 ◽  
Author(s):  
G. G. Fazio
Keyword(s):  
Gamma Radiation ◽  
Gamma Ray ◽  
Galactic Center ◽  
Galactic Plane ◽  
Crab Nebula ◽  
High Energy ◽  
Continuous Emission ◽  
X Ray ◽  
The Crab Nebula ◽  
Variable Radio

The origin of the gamma-radiation from the galactic plane and the region near the galactic center is still uncertain. However, during this meeting, several groups reported evidence for discrete sources of cosmic gamma-rays. Most of the sources are located near the galactic plane, and some are associated with X-ray sources. The galactic gamma-radiation may be due to these previously unresolved sources. Other sources detected may be associated with variable radio galaxies.The Crab Nebula still remains the most investigated source at gamma-ray energies. Pulsed emission from NP0532 was detected in the 10 to 30 MeV region, but no continuous emission was observed. At the highest energies, pulsed emission was reported at ∼1012 eV. Continuous emission from the Crab Nebula was observed at ∼1011 eV; the radiation may be time variable.The recent gamma-ray experiments on Apollo 15 and 16 and the ESRO satellite TD-1 are described, as well as future experiments on the satellites SAS-B, COS-B, and HEAO-B.

scholarly journals The Crab nebula variability at short time-scales with the Cherenkov telescope array

2020 ◽  
Vol 501 (1) ◽  
pp. 337-346
Author(s):  
E Mestre ◽  
E de Oña Wilhelmi ◽  
D Khangulyan ◽  
R Zanin ◽  
F Acero ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Crab Nebula ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Telescope Array ◽  
Cherenkov Telescopes ◽  
Cherenkov Telescope ◽  
Emission Models ◽  
Short Time ◽  
The Crab Nebula

ABSTRACT Since 2009, several rapid and bright flares have been observed at high energies (>100 MeV) from the direction of the Crab nebula. Several hypotheses have been put forward to explain this phenomenon, but the origin is still unclear. The detection of counterparts at higher energies with the next generation of Cherenkov telescopes will be determinant to constrain the underlying emission mechanisms. We aim at studying the capability of the Cherenkov Telescope Array (CTA) to explore the physics behind the flares, by performing simulations of the Crab nebula spectral energy distribution, both in flaring and steady state, for different parameters related to the physical conditions in the nebula. In particular, we explore the data recorded by Fermi during two particular flares that occurred in 2011 and 2013. The expected GeV and TeV gamma-ray emission is derived using different radiation models. The resulting emission is convoluted with the CTA response and tested for detection, obtaining an exclusion region for the space of parameters that rule the different flare emission models. Our simulations show different scenarios that may be favourable for achieving the detection of the flares in Crab with CTA, in different regimes of energy. In particular, we find that observations with low sub-100 GeV energy threshold telescopes could provide the most model-constraining results.

First results of LHAASO

2021 ◽  
Author(s):  
Ruo-Yu Liu
Keyword(s):  
High Altitude ◽  
Detailed Analysis ◽  
Confidence Level ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Ultrahigh Energy ◽  
Air Shower ◽  
First Results ◽  
Energy Gamma

The Large High Altitude Air Shower Observatory (LHAASO) has recently published the first results, including the discovery of 12 ultrahigh-energy gamma-ray sources (with emission above 100[Formula: see text]TeV) above [Formula: see text] confidence level and a detailed analysis of Crab Nebula. This contribution gives a brief introduction to the LHAASO experiment and its recent discoveries.

scholarly journals Chambre à étincelles optique pour la recherche de sources de rayons gamma

1971 ◽  
Vol 41 ◽  
pp. 79-86
Author(s):  
J. Vasseur ◽  
J. Paul ◽  
B. Parlier ◽  
J. P. Leray ◽  
M. Forichon ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Plastic Scintillator ◽  
Crab Nebula ◽  
Time Of Arrival ◽  
Gamma Emission ◽  
Cerenkov Counter ◽  
Stereo Camera ◽  
Millisecond Accuracy ◽  
The Crab Nebula

A gamma-ray telescope with a 850 cm2 multiplate spark chamber as a detector, has been used in an experiment of six balloon flights to investigate the Crab Nebula Pulsar 0532. The triggering signal is provided by a plastic scintillator-directional Čerenkov counter system. The spark chamber events are photographed by a stereo camera. The time of arrival of each event is recorded in UTC time with one millisecond accuracy, to search for a possible pulsed gamma emission from NP0532 above 50 MeV.

VERITAS Prototype Performance and Construction Status

2005 ◽  
Vol 20 (14) ◽  
pp. 3154-3155
Author(s):  
◽  
T. B. HUMENSKY
Keyword(s):  
Energy Band ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Cherenkov Telescopes ◽  
Gamma Ray Astronomy ◽  
The Crab Nebula

VERITAS is an array of 12-m imaging air-Cherenkov telescopes dedicated to gamma-ray astronomy in the 50 GeV - 50 TeV energy band. A prototype telescope was successfully operated between September 2003 and April 2004, yielding detections of the Crab Nebula and Mrk421 blazar. Construction has begun on the full array.

scholarly journals Time-Domain Astronomy with Swift, Fermi and Lobster

2011 ◽  
Vol 7 (S285) ◽  
pp. 41-46 ◽  
Author(s):  
Neil Gehrels ◽  
Scott D. Barthelmy ◽  
John K. Cannizzo
Keyword(s):  
Gamma Ray ◽  
Crab Nebula ◽  
High Energy ◽  
Tidal Disruption ◽  
X Ray ◽  
Order Of Magnitude ◽  
New Type ◽  
The Crab Nebula ◽  
High Energy Emission ◽  
Higher Sensitivity

AbstractThe dynamic transient gamma-ray sky is revealing many interesting results, largely due to findings by Fermi and Swift. The list includes new twists on gamma-ray bursts (GRBs), a GeV flare from a symbiotic star, GeV flares from the Crab Nebula, high-energy emission from novae and supernovae, and, within the last year, a new type of object discovered by Swift—a jetted tidal disruption event. In this review we present highlights of these exciting discoveries. A new mission concept called Lobster is also described; it would monitor the X-ray sky at order-of-magnitude higher sensitivity than current missions can.

scholarly journals Gamma-ray line features from the Crab Nebula in the energy range 50-2000 keV

1983 ◽  
Vol 205 (2) ◽  
pp. 285-295 ◽  
Author(s):  
C. A. Ayre ◽  
P. N. Bhat ◽  
Y. Q. Ma ◽  
R. M. Myers ◽  
M. G. Thompson
Keyword(s):  
Energy Range ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Line Features ◽  
The Crab Nebula

No indication of excess MeV gamma radiation from the Crab Nebula

Nature ◽  
1975 ◽  
Vol 257 (5525) ◽  
pp. 375-376 ◽  
Author(s):  
V. SCHÖNFELDER ◽  
G. LICHTI ◽  
C. MOYANO
Keyword(s):  
Gamma Radiation ◽  
Crab Nebula ◽  
The Crab Nebula
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