Revealing jet radio emission from intermediate-mass black holes
Abstract
Relativistic jets were first discovered in the nuclei of galaxies. The later finding of collimated jets arising from the compact counterpart of X-ray binaries suggested that jets should be present not only in supermassive and stellar-mass black holes, but also in intermediate-mass black holes (IMBHs). According to evolutionary models of black hole growth, IMBHs could be the initial seed of supermassive black holes. They could form from very young and massive stars or from the direct collapse of pre-galactic gas discs. These processes should have left a population of IMBHs in the haloes of galaxies, where they could be observed as ultraluminous X-ray sources (ULXs). However, observational evidence of IMBHs and of their jet radio emission is scarce. I will review the few detected IMBHs with jet radio emission and present the results of European VLBI Network (EVN) observations aimed at studying radio emission in ULXs and clarifying the nature of these sources. The EVN observations revealed compact radio emission from the ULX N5457-X9, which becomes a potential IMBH candidate, as well as the detection of pc-scale jet emission from an IMBH in the spiral arm of NGC 2276. With a total radio lobe size of ∼650 pc, this source could be the largest non-nuclear extragalactic jet ever discovered.
- Publication:
-
Proceedings of the 12th European VLBI Network Symposium and Users Meeting (EVN 2014). 7-10 October 2014. Cagliari
- Pub Date:
- 2014
- DOI:
- 10.22323/1.230.0002
- Bibcode:
- 2014evn..confE...2M