出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present the results of VLBI and MERLIN observations of the massive disk galaxy IC 2497.
Optical observations of IC 2497 revealed the existence of a giant emission nebula "Hanny’s Voorwerp"
in the proximity of the galaxy. Earlier short-track 18 cm observations with e-VLBI at l
18 cm, detected a compact radio component (C1) at the centre of IC 2497. The brightness temperature
of C1 was measured to be > 4 105 K. Deeper, long-track e-VLBI observations presented
here, re-confirm the existence of C1 but also reveal the existence of a second compact component
(C2) located about 230 milliarcseconds to the North-East of C1. The brightness temperature of
C2 is measured to be > 1.4 105 K, suggesting that both components may be related to AGN
activity (e.g. a radio core and jet hotspot). Lower resolution l 18 cm MERLIN observations
show both components. C1 is shown to be compact with a slight elongation along the direction of
Hanny’s Voorwerp, and C2 shows a lot of extended emission in an almost perpendicular direction
to the direction of the Voorwerp. Our results continue to support the hypothesis that IC 2497
contains an Active Galactic Nucleus (AGN), and that a jet associated with this AGN clears a path
that permits ionising radiation from the AGN to directly illuminate the emission nebula.
