Gamma-Ray Imaging of the Crab and Vela Regions with the UCR Double Compton Telescope
Session 66 -- Supernova Remnants
Oral presentation, Thursday, 2, 1994, 10:00-11:30

## [66.05] Gamma-Ray Imaging of the Crab and Vela Regions with the UCR Double Compton Telescope

A. Sarmouk (University of california, Riverside)

Results are presented for a new imaging technique applied to the reconstruction of celestial gamma-ray source images. This algorithm uses an expectation maximization maximum likelihood method (EMML) and is applied to the UCR double Compton telescope. This technique has been applied to the Crab pulsar/Nebula and the Vela regions. These data were collected in 1988 from Alice Springs, Australia and in 1989 from Fort Sumner, New Mexico. An excess of 1200 counts from the Crab has been detected at $4\sigma$ in the energy range 1-30 MeV, 920 counts at $3\sigma$ in the energy range 1-5 MeV and 202 counts at $2.7\sigma$ in the energy range 5-10 MeV. The total measured flux from 1-30 MeV is (2.0 $\pm$ 0.5) $\times$ 10$^{-3}$ photons cm$^{-2}$ s$^{-1}$. Pulsar analysis was also performed. The pulsed flux in the energy range 1-30 MeV is equal to (1.4 $\pm$ 0.4) $\times$ 10$^{-3}$ photons cm$^{-2}$ s$^{-2}$. $2\sigma$ upper limits for the pulsed flux have been placed in the individual energy range of 5-10 MeV and 10-30 MeV. The Vela region image shows an excess of 575 counts in the energy range 1.1-30 MeV at 2.8$\sigma$, 340 counts at 2.4$\sigma$ in the energy range 1.1-5 MeV and 130 counts from 5 to 10 MeV at 2.2$\sigma$. No excess is seen above 10 MeV. The total flux for the energy range 1.1 to 30 MeV is equal to (1.0 $\pm$ 0.4) $\times$ 10$^{-3}$ photons cm$^{-2}$ s$^{-1}$. The Vela pulsed flux in the energy range 1.1 to 30 MeV is equal to (3.5 $\pm$ 1.4) $\times$ 10$^{-4}$ photons cm$^{-2}$ s$^{-2}$.