Very high energy gamma rays from the Crab nebula and pulsar

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6711033

Kwok, P W

This project is to search for very high energy (VHE) (10(exp 11) to 10(exp 14)eV) gamma rays from the Crab nebula and pulsar using the atmospheric Cherenkov imaging technique. The technique uses an array of 37 photomultiplier tubes to record the images of the Cherenkov light pulses generated by energetic particles in the air showers initiated by VHE gamma rays or charged cosmic rays. Gamma ray like events are selected from numerous cosmic ray events based on the predicted properties of the image, such as the size, shape, and orientation with respect to the axis of the detector. A steady weak flux of VHE gamma rays from the Crab is detected at high statistical significance (9 sigma), which is not usually achieved in VHE gamma ray astronomy. No strong evidence of pulsed emission is found when the same data is folded at the Crab pulsar's radio ephemeris. The angular resolution of the technique cannot separate the emission coming from the nebula from that from the pulsar. Although it is generally believed that the unpulsed emission is coming from the nebula, there may be an unpulsed component coming at only a couple of light cylinder radii away from the pulsar too. Using the outer gap model of pulsar, the spectrum is derived and is found to be compatible with the observations.

• Research Organization: Arizona Univ., Tucson, AZ (USA)
• OSTI ID: 6711033
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHERENKOV RADIATION
COSMIC RADIATION
COSMIC RADIO SOURCES
CRAB NEBULA
DATA
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
GAMMA SPECTRA
INFORMATION
IONIZING RADIATIONS
MATHEMATICAL MODELS
NEBULAE
NUMERICAL DATA
PULSARS
RADIATIONS
SPECTRA
STAR MODELS
SUPERNOVA REMNANTS