Stefano Ciprini

The 3rd Catalog of AGN Detected by the Fermi LAT

The third catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (3LAC) is presented. It is based on the third catalog (3FGL,cite{3FGL}) of sources detected with a test statistic greater than 25, using the first 4 years of data. The 3LAC includes 1591 AGNs located at high (

Four years of Fermi LAT flare advocate activity

|b|>10^circ

Multi-wavelength observations of blazar 4C + 49.22 during flaring state

) Galactic latitudes (with 28 duplicate associations, thus corresponding to 1563 gamma-ray sources among 2192 sources in the 3FGL catalog), providing

Monitoring the Gamma-ray Sky through 4.5 Years of Fermi LAT Flare Advocate Service

71%

Gamma-Ray Band and Multi-Waveband Variability of Blazars with the Fermi Large Area Space Telescope

more sources with respect to the 2FGL. Various properties, such as gamma-ray fluxes and photon power law spectral indices, redshifts, gamma-ray luminosities, variability, and their correlations are presented and discussed for the different blazar and non-blazar classes.

Possible Quasi-Periodic Gamma-ray Emission from Blazar PG 1553+113

The Fermi Flare Advocate (also known as Gamma-ray Sky Watcher, FA-GSW) service provides for a daily quicklook analysis and review of the high-energy gamma-ray sky seen by the Fermi Large Area Telescope (LAT). The FA-GSW service communicates alerts for potentially new gamma-ray sources, interesting transients and flares. A weekly digest containing the highlights about the GeV gamma-ray sky is published in the web-based Fermi Sky Blog and email for special events are posted through the LAT multifrequency mailing-list. During the first 4 years of Fermi allsky survey, more than 200 Astronomical Telegrams, several alerts to the TeV Cherenkov telescopes, and target of opportunity to Swift and other observatories have been realized. This increased the rate of simultaneous multi-frequency observing campaigns and the level of international scientific cooperation.

Fermi LAT Flare Advocate Activity

The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope detected a strong γ-ray flare on 2011 May 15 from a source identified through dedicated and intensive followup multifrequency observations with the core-dominated and compact flat spectrum radio quasar 4C + 49.22 (also known as S4 1150+49, SBS 1150+497, z=0.334). 4C + 49.22 was in a low γ-ray activity during the first year of Fermi survey operations and it is not included in the first Fermi - LAT Source Catalog (1FGL [1]). Simultaneous multi-wavelength observations during the transition phase including the quiescent, outburst and post-flare γ-ray states are obtained by Swift, Planck and ground-based optical observatories and radio observatories (INAOE, Catalina CSS, VLBA). The flaring state was observed also from microwaves to X-ray bands, and correlated variability is found.