Title: Constraints on the Intergalactic Magnetic Field from Bow Ties in the Gamma-ray Sky,
Abstract: Pair creation on the cosmic infrared background and subsequent
inverse-Compton scattering on the CMB potentially reprocesses the TeV emission
of blazars into faint GeV halos with structures sensitive to intergalactic
magnetic fields (IGMF). We attempt to detect such halos exploiting their highly
anisotropic shape. Their persistent nondetection excludes at greater than
$3.9\sigma$ an IGMF with correlation lengths >100 Mpc and current-day strengths
in the range $10^{-16}$ to $10^{-15}$ G, and at 2 sigma from $10^{-17}$ to
$10^{-14}$ G, covering the range implied by gamma-ray spectra of nearby TeV
emitters. Alternatively, plasma processes could pre-empt the inverse-Compton
cascade.