A Multi-telescope Campaign on FRB 121102: Implications for the FRB Population

C. J. Law, M. W. Abruzzo, C. G. Bassa, G. C. Bower, S. Burke-Spolaor, B. J. Butler, T. Cantwell, S. H. Carey, S. Chatterjee, J. M. Cordes, P. Demorest, J. Dowell, R. Fender, K. Gourdji, K. Grainge, J. W. T. Hessels, J. Hickish, V. M. Kaspi, T. J. W. Lazio, M. A. McLaughlin, D. Michilli, K. Mooley, Y. C. Perrott, S. M. Ransom, N. Razavi-Ghods, M. Rupen, A. Scaife, P. Scott, P. Scholz, A. Seymour, L. G. Spitler, K. Stovall, S. P. Tendulkar, D. Titterington, R. S. Wharton, P. K. G. Williams

Published 2017-05-22Version 1

We present results of the coordinated observing campaign that made the first subarcsecond localization of a Fast Radio Burst, FRB 121102. During this campaign, we made the first simultaneous detection of an FRB burst by multiple telescopes: the VLA at 3 GHz and the Arecibo Observatory at 1.4 GHz. Of the nine bursts detected by the Very Large Array at 3 GHz, four had simultaneous observing coverage at other observatories. We use multi-observatory constraints and modeling of bursts seen only at 3 GHz to confirm earlier results showing that burst spectra are not well modeled by a power law. We find that burst spectra are characterized by a ~500 MHz envelope and apparent radio energy as high as $10^{40}$ erg. We measure significant changes in the apparent dispersion between bursts that can be attributed to frequency-dependent profiles or some other intrinsic burst structure that adds a systematic error to the estimate of DM by up to 1%. We use FRB 121102 as a prototype of the FRB class to estimate a volumetric birth rate of FRB sources $R_{FRB} \approx 5x10^{-5}/N_r$ Mpc$^{-3}$ yr$^{-1}$, where $N_r$ is the number of bursts per source over its lifetime. This rate is broadly consistent with models of FRBs from young pulsars or magnetars born in superluminous supernovae or long gamma-ray bursts, if the typical FRB repeats on the order of thousands of times during its lifetime.