Fermi Gamma-ray Space Telescope

Fermi ToO 060623-1-1

A ToO observation to observe PSR B1259-63 at RA, Dec = 195.6986, -63.8357 (J2000) was approved at 2014-05-30 20:32:44 UTC.

The justification for the ToO is: This is a very important gamma-ray source. Periastrons occur every 3.4 years. Each cycle is a new experiment in collision of a pulsar wind with a strong stellar outflow. No other source presents a comparably clean, repeatable experiment in wind interactions. The major flare seen last cycle inspired new theories that need to be tested. That flare reached a luminosity comparable to the spindown energy loss of the pulsar, the apparent energy supply for the flare. It would be extremely unfortunate to find that Fermi results were marginal but could have been made statistically significant by exercising a TOO option. The phase of the earlier flare is only a few days away. It is important to catch the rise of the flare with the best sensitivity available.

The planned duration is 600.00 ks.

The autonomous request threshold during this ToO is LOW.

The ToO observation should begin between 2014-05-30 20:32:43 UTC and 2014-06-06 20:32:43 UTC.

The ToO observation was requested by DR. KENT S WOOD.