Black Hole Search Begins In Australian Outback

Sandeater writes: "BBC news is reporting that an new telescope has just been completed to search out black holes from the Australian outback. The astronomers using the telescope will be looking for huge black holes at the centres of galaxies, as well as seeing how they evolve. The Cangaroo II will be offically opened tomorrow. The BBC link can be found here."

Comments

Why it's ground based

[spiralx]

Well, for one, the cost of a ground based installation is much less than a satellite, but that's the obvious answer :)

What they're doing is looking for the Cerenkov radiation produced when a high energy gamma ray from the "blazar" produced by a black hole hits the upper atmosphere. Cerenkov radiation is the product of electron/positron pair creation and bremmstrahlung and consists of relativistic particles which travel at velocities faster than the local speed of light. This results in the production of Cerenkov radiation in the blue part of the visible spectrum, which is what the telescopes actually detect.

However there is a far greater amount of Cerenkov radiation from normal cosmic ray incidents than there is from gamma rays produced in blazars. Since the cosmic ray particles are charged (they are usually protons) whereas the gamma rays aren't, they can be distinguished by whether they curve in the galactic magnetic field.

Anyway, since this is a proven technique, there's really no need for a space-based detector as of yet.