A fast radio burst’s extragalactic home
DOI: 10.1063/PT.3.3487
Discovered in 2007, fast radio bursts (FRBs) emit luminous pulses of radio light that last mere milliseconds. To date, astronomers have reported about 20 FRBs but don’t know what causes them. One, identified in 2014 by Laura Spitler and colleagues, stands apart because it has been observed to burst repeatedly (see Physics Today, April 2016, page 22 ). The source was first detected on 2 November 2012, hence its designation FRB121102. An international team took advantage of FRB121102’s ongoing intermittent activity to run a series of follow-up observations with several radio telescopes in the US and Europe and has located FRB121102 with unprecedented precision. The radio observations didn’t just refine the location of FRB121102, they also spotted a persistent source coincident with the FRB, to within experimental uncertainty. It is possible that the persistent source is related to the FRB; it could be, for example, a highly energetic neutron star in a young supernova remnant or an unusual active galactic nucleus.
DANIELLE FUTSELAAR
The researchers also observed the neighborhood of FRB121102 with the Gemini North optical telescope. They determined that the location of the FRB coincides with that of a dwarf galaxy some 3 billion light-years distant from Earth. Although astronomers had expected FRBs to lie beyond the Milky Way, some models allowed for sources in our galaxy; the new work provides the first direct confirmation of the earlier consensus. Dwarf galaxies are more likely than regular galaxies to host two other classes of high-energy transients: superluminous supernovae and long-duration gamma-ray bursts. The observation of an FRB in a dwarf galaxy creates the tantalizing prospect that all three types of high-energy events may be generated by massive progenitors. (S. Chatterjee et al., Nature 541, 58, 2017, doi:10.1038/nature20797 ; S. P. Tendulkar et al., Astrophys. J. Lett. 834, L7, 2017, doi:10.3847/2041-8213/834/2/L7 ; B. Marcote et al., Astrophys. J. Lett. 834, L8, 2017, doi:10.3847/2041-8213/834/2/L8 .)
