AGILE and blazar studies

TL;DR

The paper reports on AGILE's gamma-ray observations of multiple blazars, highlighting significant detections, rapid alerts enabling multi-wavelength follow-ups, and insights into blazar variability and energy mechanisms.

Contribution

It presents new gamma-ray detections of several blazars and demonstrates the importance of rapid alerts for coordinated multi-wavelength observations.

Findings

Detection of multiple blazars at high significance

Rapid alerts facilitated multi-wavelength follow-up

Observation of fast gamma-ray transient in S5 0716+714

Abstract

During the first two years of observation, AGILE detected several blazars at high significance: 3C 279, 3C 454.3, PKS 1510-089, S5 0716+714, 3C 273, W Comae, Mrk 421 and PKS 0537-441. We obtained long-term coverage of 3C 454.3, for a total of more than three months at energies above 100 MeV. 3C 273 was the first blazar detected simultaneously by the AGILE gamma-ray detector and by its hard X-ray monitor. S5 0716+714, an intermediate BL Lac object, exhibited a very fast and intense gamma-ray transient during an optical high-state phase, challenging the current theoretical models for energy extraction from a rotating black hole, while W Comae and Mkn 421 were detected during an AGILE Target of Opportunity (ToO) repointing, and were simultaneously detected by Cherenkov telescopes. Thanks to the rapid dissemination of our alerts, we were able to obtain multi-wavelength ToO data from other observatories such as Spitzer, Swift, RXTE, Suzaku, INTEGRAL, MAGIC, VERITAS, as well as radio-to-optical coverage by means of the WEBT Consortium and REM, allowing us to study truly simultaneous spectral energy distributions from the radio to the TeV energy band.