The Remarkable γ-Ray Activity in the Gravitationally Lensed Blazar PKS 1830-211
Abstract
We report the extraordinary γ-ray activity (E > 100 MeV) of the gravitationally lensed blazar PKS 1830-211 (z = 2.507) detected by AGILE between 2010 October and November. On October 14, the source experienced a factor of ~12 flux increase with respect to its average value and remained brightest at this flux level (~500 × 10-8 photons cm-2 s-1) for about four days. The one-month γ-ray light curve across the flare showed a mean flux F(E > 100 MeV) = 200 × 10-8 photons cm-2 s-1, which resulted in a factor of four enhancement with respect to the average value. Following the γ-ray flare, the source was observed in near-IR (NIR)-optical energy bands at the Cerro Tololo Inter-American Observatory and in X-Rays by Swift/X-Ray Telescope and INTEGRAL/IBIS. The main result of these multifrequency observations is that the large variability observed in γ-rays does not have a significant counterpart at lower frequencies: no variation greater than a factor of ~1.5 appeared in the NIR and X-Ray energy bands. PKS 1830-211 is then a good "γ-ray only flaring" blazar showing substantial variability only above 10-100 MeV. We discuss the theoretical implications of our findings.
- Publication:
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The Astrophysical Journal
- Pub Date:
- August 2011
- DOI:
- 10.1088/2041-8205/736/2/L30
- arXiv:
- arXiv:1106.4224
- Bibcode:
- 2011ApJ...736L..30D
- Keywords:
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- galaxies: active;
- galaxies: jets;
- quasars: general;
- quasars: individual: PKS 1830-211;
- radiation mechanisms: non-thermal;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 7 pages, 2 figures, 1 table, accepted for publication in ApJL