The Repeating Fast Radio Burst FRB 121102: Multi-Wavelength Observations and Additional Bursts

Abstract

We report on radio and X-ray observations of the only known repeating Fast Radio Burst (FRB) source, FRB 121102. We have detected six additional radio bursts from this source: five with the Green Bank Telescope at 2 GHz, and one at 1.4 GHz with the Arecibo Observatory for a total of 17 bursts from this source. All have dispersion measures consistent with a single value (∼ 559 pc cm −3 ) that is three times the predicted maximum Galactic contribution. The 2-GHz bursts have highly variable spectra like those at 1.4 GHz, indicating that the frequency structure seen across the individual 1.4 and 2-GHz bandpasses is part of a wideband process. X-ray observations of the FRB 121102 field with the Swift and Chandra observatories show at least one possible counterpart; however, the probability of chance superposition is high. A radio imaging observation of the field with the Jansky Very Large Array at 1.6 GHz yields a 5σ upper limit of 0.3 mJy on any point-source continuum emission. This upper limit, combined with archival WISE 22-µm and IPHAS Hα surveys, rules out the presence of an intervening Galactic H II region. We update our estimate of the FRB detection rate in the PALFA survey to be 1.1 +3.7 −1.0 × 10 4 FRBs sky −1 day −1 (95% confidence) for peak flux density at 1.4 GHz above 300 mJy. We find that the intrinsic widths of the 12 FRB 121102 bursts from Arecibo are, on average, significantly longer than the intrinsic widths of the 13 single-component FRBs detected with the Parkes telescope.

The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102

“…Our measurement of the redshift z = 0.19273 is consistent with the DM-estimated value of z DM <0.32 (Chatterjee et al 2017) and together with the very low chance superposition probability firmly places FRB 121102 at a cosmological distance, ruling out all Galactic models for this source, consistent with the conclusions of Scholz et al (2016) and Chatterjee et al (2017).…”

“…Repeated radio bursts were observed from the location of the Arecibo-detected FRB 121102 Scholz et al 2016), with the same DM as the first detection, indicating a common source. As discussed by Spitler et al (2016), it is unclear whether the repetition makes FRB 121102 unique among known FRBs, or whether radio telescopes other than Arecibo lack the sensitivity to readily detect repeat bursts from other known FRBs.…”

“…We note, of course, that our above discussion regarding the possible relationship between FRBs and dwarf galaxies in general is based on a single data point of a repeating FRB, which may not be representative of the broader FRB population (see Scholz et al 2016;Spitler et al 2016 for more details).…”

The Fate of Neutron Star Binary Mergers

“…Even the highest rate of supramassive NSs by APR4 will only produce roughly ∼1% of FRBs (Rane et al 2016;Nicholl et al 2017). Furthermore, the repeating FRB 121102 (Spitler et al 2014Scholz et al 2016) cannot be reconciled with such a scenario in which the FRB is generated in a single catastrophic event.…”

A Search for Fast Radio Bursts with the GBNCC Pulsar Survey

“…Additionally, if the latitude dependence of the FRB event rate is due to diffractive scintillation, as suggested by Macquart & Johnston (2015), then the frequency dependence of this effect can also weaken the spectral index constraints. However, we do not account for this effect here since Scholz et al (2016) demonstrate that the analysis by Macquart & Johnston (2015) is incorrect, as its prediction for a high FRB rate with the PALFA survey is not matched by observations.…”