Naslov
MAGIC and Swift detection of renewed activity from the blazar PG1553+113 during a MWL campaign

Autori
Aleksić, Jelena ; ... ; Dominis Prester, Dijana ; ... ; Ferenc, Daniel ; ... ; Godinović, Nikola ; ... ; Hrupec, Dario ; ... ; Lelas, Damir ; ... ; Puljak, Ivica ; ... ; Surić, Tihomir ; ... ; Šnidarić, Iva ; ... ; Terzić, Tomislav ; ...

Izvornik
The Astronomer's Telegram, #3977

Vrsta, podvrsta
Ostale vrste radova, ostalo

Godina
2012

Ključne riječi
Radio ; Infra-Red ; Optical ; Ultra-Violet ; X-ray ; Gamma Ray ; >GeV ; TeV ; VHE ; Request for Observations ; AGN ; Blazar

Sažetak
The MAGIC telescopes have observed an increased VHE (E>~100 GeV) gamma-ray flux from the blazar PG 1553+113 in the course of a multi-wavelength campaign started on 2012 February 23. PG 1553+113 (RA: 15h 55m 43.0s Dec: +11d 11m 24s) is a TeV BL-Lac object likely located at redshift 0.4-0.5 (Danforth et al. 2010). Between February 23 and March 5 an extensive multi-wavelength campaign coordinated by the MAGIC Collaboration was performed, involving besides MAGIC, radio (Metsahovi), near-infrared (REM), optical (KVA), UV (Swift/UVOT), and X-ray (Swift/XRT) observations. Preliminary analysis of MAGIC data shows a firm detection with significance around 15 sigma in 4 hours of good quality data. According to this analysis the estimated flux is above 15% Crab in the VHE range, one of the highest fluxes ever detected from PG 1553+113. The analysis of MAGIC data is still in progress. Preliminary analysis of X-ray data taken with Swift/XRT reports a 2-10 keV flux rising from (16.8+/-1.0)E-12 erg/cm2/s to (23.0+/-1.3)E-12 erg/cm2/s between February 16 to March 2. The XRT spectrum obtained on single daily snapshots is fairly fitted with an absorbed power law with an absorbing column density fixed to the Galactic value of 3.65E20 cm-2 (Kalberla et al. 2005), yielding a photon index around 2.3+/-0.1, relatively stable within errors. Swift/UVOT observed with all the optical and UV filters, providing the following preliminary averaged magnitudes, not corrected for absorption, and fluxes, corrected for Galactic extinctions due to reddening of E(B-V)=0.052 mag in the direction of the source (Schlegel et al 1998).

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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