VLBA19A-005

Unveiling the particle acceleration regions in two X-ray emitting hotspots

Abstract

We propose high sensitivity array (HSA) observations at 5 GHz of the X-ray synchrotron emitting hotspots 3C 227 West and 3C 445 South. The discovery in these hotspots of diffuse optical and X-ray synchrotron emission requires a revision of the standard scenario of particles accelerated by a single strong shock generated at the jet termination. High energy electrons
like those responsible for the X-ray emission should arise from very small regions because their short lifetime should limit their emission at a narrow emitting disk. Extended emission may be interpreted in terms of
either multiple, transient shock structures likely produced by jet
dithering, or turbulence. Our new Jansky Very Large Array (JVLA) observations of these hotspots point out the presence of unresolved regions and set an upper limit to their size of about 75 mas (about 100 pc). However, the expected size of transient features should be of the order of a few parsecs, i.e. much smaller than the size proved by the JVLA observations. The proposed HSA observations will allow us to constrain the size of these transient regions, improving our knowledge of jet interaction processes at the edge of powerful radio galaxies.

Investigators

Name	Institution
Giulia Migliori	Istituto Nazionale di Astrofisica
Filippo D'Ammando	Istituto Nazionale di Astrofisica
Lodovico Coccato	European Southern Observatory
Gianfranco Brunetti	Istituto Nazionale di Astrofisica
Monica Orienti *	Istituto Nazionale di Astrofisica; Bologna, Università degli Studi di
GBT Operator	Green Bank Observatory

* indicates the PI