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Long-term Optical Variability of Radio-Selected Quasars from the FIRST Survey
David J. Helfand, Remington P. S. Stone, Beth Willman +5
We have obtained single-epoch optical photometry for 201 quasars, taken from the FIRST Bright Quasar Survey, which span a wide range in radio loudness. Comparison with the magnitud…
The Vela Pulsar and its Synchrotron Nebula
D. J. Helfand, E. V. Gotthelf, J. P. Halpern
(Abridged) We present high-resolution Chandra X-ray observations of PSR B0833-45, the 89 ms pulsar associated with the Vela supernova remnant. We have acquired two observations sep…
A Possible X-ray and Radio Counterpart of the High-Energy Gamma-ray Source 3EG J2227+6122
J. P. Halpern, E. V. Gotthelf, K. M. Leighly +1
The identity of the persistent EGRET sources in the Galactic plane is largely a mystery. For one of these, 3EG J2227+6122, our complete census of X-ray and radio sources in its err…