2017ApJ...835..288A

Query : 2017ApJ...835..288A

2017ApJ...835..288A - Astrophys. J., 835, 288-288 (2017/February-1)

Search for magnetically broadened cascade emission from blazars with VERITAS.

ARCHAMBAULT S., ARCHER A., BENBOW W., BUCHOVECKY M., BUGAEV V., CERRUTI M., CONNOLLY M.P., CUI W., FALCONE A., FERNANDEZ ALONSO M., FINLEY J.P., FLEISCHHACK H., FORTSON L., FURNISS A., GRIFFIN S., HUTTEN M., HERVET O., HOLDER J., HUMENSKY T.B., JOHNSON C.A., KAARET P., KAR P., KIEDA D., KRAUSE M., KRENNRICH F., LANG M.J., LIN T.T.Y., MAIER G., McARTHUR S., MORIARTY P., NIETO D., O'BRIEN S., ONG R.A., OTTE A.N., POHL M., POPKOW A., PUESCHEL E., QUINN J., RAGAN K., REYNOLDS P.T., RICHARDS G.T., ROACHE E., ROVERO A.C., SADEH I., SHAHINYAN K., STASZAK D., TELEZHINSKY I., TYLER J., WAKELY S.P., WEINSTEIN A., WEISGARBER T., WILCOX P., WILHELM A., WILLIAMS D.A. and ZITZER B.

Abstract (from CDS):

We present a search for magnetically broadened gamma-ray emission around active galactic nuclei (AGNs), using VERITAS observations of seven hard-spectrum blazars. A cascade process occurs when multi-TeV gamma-rays from an AGN interact with extragalactic background light (EBL) photons to produce electron-positron pairs, which then interact with cosmic microwave background photons via inverse-Compton scattering to produce gamma-rays. Due to the deflection of the electron-positron pairs, a non-zero intergalactic magnetic field (IGMF) would potentially produce detectable effects on the angular distribution of the cascade emission. In particular, an angular broadening compared to the unscattered emission could occur. Through non-detection of angularly broadened emission from 1ES 1218+304, the source with the largest predicted cascade fraction, we exclude a range of IGMF strengths around 10–14 G at the 95% confidence level. The extent of the exclusion range varies with the assumptions made about the intrinsic spectrum of 1ES 1218+304 and the EBL model used in the simulation of the cascade process. All of the sources are used to set limits on the flux due to extended emission.

Abstract Copyright: © 2017. The American Astronomical Society. All rights reserved.

Journal keyword(s): BL Lacertae objects: general - galaxies: active - gamma rays: galaxies - magnetic fields - magnetic fields

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 RX J0232.8+2017 BLL 02 32 48.6148874688 +20 17 17.486717388     18.00 13.96   ~ 387 1
2 RX J0521.7+2112 BLL 05 21 45.9657388992 +21 12 51.452786736           ~ 162 1
3 M 1 SNR 05 34 31.8 +22 01 03           ~ 6516 1
4 PMN J1103-2329 BLL 11 03 37.6150845072 -23 29 31.203773520   17.00 16.55 16.61   ~ 405 1
5 Z 184-50 BLL 11 04 27.3140835504 +38 12 31.798495872   13.50 12.90 8.31   ~ 2841 1
6 PG 1218+304 BLL 12 21 21.9426947832 +30 10 37.158534012   16.50 15.85 15.7   ~ 497 1
7 RX J1428.5+4240 BLL 14 28 32.6090008440 +42 40 21.048123396   16.95 16.45 14.4   ~ 549 1
8 PG 1553+113 BLL 15 55 43.0440048528 +11 11 24.365649948 14.91 14.72 14.57 13.99   ~ 672 1
9 Z 225-7 BLL 16 53 52.21668403 +39 45 36.6088754 14.09 14.15 13.29 8.26   ~ 2304 2
10 PKS J2158-3013 BLL 21 58 52.0652249880 -30 13 32.118447792   13.36 13.09 12.62   ~ 1829 1

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