The TeV HBL blazar 1ES 1011+496 in Gamma-, X-, Optical flaring activity
ATel #7267; Luigi Pacciani (IAPS-INAF Italy), Antonio Stamerra (INAF-Italy & SNS Pisa Italy)
on 21 Mar 2015; 16:10 UT
Credential Certification: Luigi Pacciani (luigi.pacciani@iaps.inaf.it)
Subjects: Optical, Ultra-Violet, X-ray, Gamma Ray, >GeV, AGN, Blazar
We detected a gamma-ray flare from the TeV HBL blazar 1ES 1011+496 (z=0.212), triggering on FERMI-LAT data at E > 10 GeV with TS ~50, from 2015-03-12 to 2015-03-16, following the prescription of Pacciani et al. 2014, ApJ, 790, 45.
The gamma-ray flux was (3.0+/-0.9)E-8 ph cm^-2 s^-1, photon index 1.32+/-0.25, TS ~94 (E>1 GeV),
to be compared with the catalog flux of (0.73+/-0.02)E-8 ph cm^-2 s^-1 reported in the 3rd Fermi-LAT point-source catalog.
The Swift Follow-up revealed the source in high state in optical and X-ray.
The preliminary Swift-UVOT photometry on 2015-03-17 is:
V = 15.69 +/- 0.05
B = 16.01 +/- 0.03
U = 15.02 +/- 0.03
UVW1 = 14.89 +/- 0.03
UVM2 = 14.69 +/- 0.02
UVW2 = 14.79 +/- 0.02
which is 5-15% brighter then the peak flux on 2014.
Magnitudes are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) and have not been corrected for Galactic extinction.
The simultaneous Swift-XRT observation gives a counting rate of 4.2 cps (to be compared with 5.1 cps of the brightest state on 2014-02-25, Swift obsid 00035012033 http://www.swift.psu.edu/monitoring/source.php?source=1ES1011+496 , and ATel 5866 http://www.astronomerstelegram.org/?read=5866 ) and a flux of (1.02+/-0.07)E-10 erg cm^-2 s^-1 (0.3-10 keV).
We fit an absorbed log-parabola model to the data, obtaining
alpha=1.65 +/-0.15 , beta=0.49 +/- 0.12, Epivot=0.3keV, Epeak~0.7 keV,
nH fixed at the galactic value of 8.4E19cm-2, chi2/ndof =0.97).
We encourage further multi-wavelength observations, particularly TeV observations.
We thank the Swift team and Swift Observatory Duty Scientist for rapidly scheduling our observations.
