QUASAR MONITORING

DESCRIPTION:
We are monitoring 20 flat spectrum radio quasars with Fermi to trigger VERITAS observations in case of flare. Details on the source selection, physics case and trigger criteria can be found in our TAC proposal.
The plots show the arrival time and energy (orange dots) of high energy photons for the selected quasars during the last 15 days. In order to meet the trigger threshold, 2 or more photons with energy larger than 10 GeV must be observed in the last 2 days. The trigger window is indicated in blue. The analysis is automatically launched every 30 minutes, but new photon hits will only appear when new Fermi data is available (approximately 4 times a day). As Fermi data is not public immediately, a red dashed line indicates the last Fermi data that was available at the time of download. Typical time gap is between 6 and 10 hours.
Example plot
Fig 1: Example photon arrival plot
Example plot
Fig 2: Crab Nebula plot (for monitoring purposes)

Photons are selected if the arrival direction is within a 95% containment radius of the Fermi PSF, which evaluated according to the photon energy separately for front and back converting photons:
Example plot
Fig 3: Fermi PSF

CONTACT:

Manel Errando (errando at astro.columbia.edu)
Erin Kara (ek2398 at barnard.edu)