Fermi Gamma-ray Space Telescope

Fermi ToO 060624-1-1

A ToO observation to observe PSR B1259-63 at RA, Dec = 195.6986, -63.8357 (J2000) was approved at 2014-06-03 18:59:28 UTC.

The justification for the ToO is: This is a very important gamma-ray source. Periastron events come every 3.4 years. Each cycle is a new experiment in the collision of a pulsar wind with a strong stellar outflow. No other source presents a comparably clean, repeatable experiment in wind interactions. The last encounter was winter of Dec 2010-11 and the next will not be until 2017. The major flare seen last cycle inspired many new theories that need to be tested with observations from this cycle. The flare was so bright that it reached a luminosity comparable to the spindown energy loss of the pulsar. It would be extremely unfortunate to discover that Fermi results were marginal but could have been made statistically significant by exercising a TOO option. For 3 days starting May 31, the TOO has doubled exposure.

The planned duration is 605.00 ks.

The autonomous request threshold during this ToO is LOW.

The ToO observation should begin between 2014-06-03 18:59:27 UTC and 2014-06-10 18:59:27 UTC.

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