APOD: Fermi's Gamma-ray Moon (2016 Apr 29)

[neufer]

Why is the Vela Pulsar so bright in gamma rays? I believe that it is pretty bright in X-rays too, although not strikingly bright in X-rays compared with everything else in the Milky Way. (The X-ray Vela Pulsar is probably the yellow dot located about halfway to the right edge from the center.) But what is that makes the Vela Pulsar so gamma-ray bright? Why is it so much brighter in gamma rays than the pulsar in the Crab Nebula, for example?

The Vela Pulsar is in our back yard... over 7 times closer than the pulsar in the Crab Nebula.

<<The Vela supernova remnant (SNR) is one of the closest known to us. The Geminga pulsar is closer (and also resulted from a supernova), and in 1998 another supernova remnant was discovered, RX J0852.0-4622, which from our point of view appears to be contained in the southeastern part of the Vela remnant. One estimate of its distance puts it only 200 parsecs away (about 650 ly), closer than the Vela remnant, and, surprisingly, it seems to have exploded much more recently (in the last thousand years or so) because it is still radiating gamma rays from the decay of titanium-44. This remnant was not seen earlier because in most wavelengths it is lost in the image of the Vela remnant.>>