Bibcode
Quinn, J.; Jackson, Neal; Tagore, Amitpal; Biggs, Andrew; Birkinshaw, Mark; Chapman, Scott; De Zotti, Gianfranco; McKean, John; Pérez-Fournon, I.; Scott, Douglas; Serjeant, Stephen
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 459, Issue 3, p.2394-2407
Advertised on:
7
2016
Citations
24
Refereed citations
20
Description
We present the new Very Large Array 22 GHz and extended Multi-Element
Remote-Linked Interferometer Network 5 GHz observations of CLASS
B1030+074, a two-image strong gravitational lens system whose background
source is a compact flat-spectrum radio quasar. In such systems we
expect a third image of the background source to form close to the
centre of the lensing galaxy. The existence and brightness of such
images is important for investigation of the central mass distributions
of lensing galaxies, but only one secure detection has been made so far
in a galaxy-scale lens system. The noise levels achieved in our new
B1030+074 images reach 3 μJy beam-1 and represent an
improvement in central image constraints of nearly an order of magnitude
over previous work, with correspondingly better resulting limits on the
shape of the central mass profile of the lensing galaxy. Simple models
with an isothermal outer power-law slope now require either the
influence of a central supermassive black hole (SMBH), or an inner
power-law slope very close to isothermal, in order to suppress the
central image below our detection limit. Using the central mass profiles
inferred from light distributions in Virgo galaxies, moved to z = 0.5,
and matching to the observed Einstein radius, we now find that 45 per
cent of such mass profiles should give observable central images, 10 per
cent should give central images with a flux density still below our
limit, and the remaining systems have extreme demagnification produced
by the central SMBH. Further observations of similar objects will
therefore allow proper statistical constraints to be placed on the
central properties of elliptical galaxies at high redshift.