  We investigate two potential mechanisms that will produce X-ray and gamma-ray
flashes from Type Ia supernovae (SN-Ia). The mechanisms are the breakout of the
thermonuclear burning front as it reaches the surface of the white dwarf and
the interaction of the rapidly expanding envelope with an accretion disk. Based
on the delayed-detonation scenario and detailed radiation-hydro calculation
which include nuclear networks, we find that both mechanisms produce ~1 second
flashes of high energy radiation with peak luminosities of 10^48 to 10^50
erg/sec with fast rises and exponential declines. The X- and gamma-ray
visibility of a SN-Ia will depend strongly on self absorption within the
progenitor system, specifically on the properties of the accretion disk and its
orientation towards the observer. Such X-ray and gamma-ray flashes could be
detected as triggered events by Gamma-Ray Burst (GRB) detectors on satellites,
with events in current GRB catalogs. We have searched through the GRB catalogs
(for the BATSE, HETE, and Swift experiments) for GRBs that occur at the
extrapolated time of explosion and in the correct direction for known Type Ia
supernovae with radial velocity of less than 3,000 km/s. For BATSE about
12.9+-3.6 nearby SNe Ia should have been detected, but only 0.8+-0.7
non-coincidental matches have been found. With the HETE and Swift satellites,
we expect to see 5.6+-1.3 SN-Ia flashes from known nearby SNe Ia but, yet, no
SN-Ia flashes were detected. These place observational limits that the
bolometric peak luminosity of SN-Ia Flashes must be less ~10^46 erg/s. We
attribute the difference between theory and observational limits to the
absorption of the X- and gamma-rays by the accretion disk of large scale height
or common envelope that would be smothering the white dwarf.
