A new VLA/e-MERLIN limit on central images in the gravitational lens system CLASS B1030+074

Abstract

We present new VLA 22-GHz and e-MERLIN 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, 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% of such mass profiles should give observable central images, 10% 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.

A Likely Supermassive Black Hole Revealed by Its Einstein Radius in Hubble Frontier Fields Images

“…The SMBH masses thus derived for the foreground lensing galaxies in both PMN J1632-0033 and SDP81 are in agreement with the local M BH − σ relation. Quinn et al (2016) discussed the implications for the non-detection of a central image in the lens system CLASS B1030+074 with the data from VLA and the extended Multi-Element Remote-Linked Interferometer (e-MERLIN), and argued in favour of a central SMBH with a mass slightly greater than that implied by the local M BH − σ relation, yet again, whether the SMBH is required in the lens model is dependent on the mass profile chosen for the lensing galaxy. A relatively large SMBH mass of ∼ 1.2 × 10 10 M , lying well above the M BH − σ relation, has been inferred for the brightest cluster galaxy (BCG; central giant elliptical galaxy) in the cluster Abell 1201 at z = 0.17 based on the detection of a faint central image based on observations with the Hubble Space Telescope (HST) (Smith et al 2017).…”

H0LiCOW. VI. Testing the fidelity of lensed quasar host galaxy reconstruction

“…In this paper we present extensive and realistic simulations of ultradeep HST images of lensed AGNs obtained with the goal of measuring cosmological parameters from gravitational time delays. We then analyze the simulated images with the state of the art code 1 In very rare cases gravitational lensing can also be used to estimate the black hole mass using the properties of the central image (Quinn et al 2016;Wong et al 2015;Winn et al 2004;Tamura et al 2015).…”

ALMA Observations of the Gravitational Lens SDP.9

“…These systems also present a unique opportunity to study the supermassive black hole (SMBH) at the center of the lens galaxy through the brightness of the central image of the lens (e.g., Winn et al 2004;Tamura et al 2015;Wong et al 2015;Quinn et al 2016). There are known correlations between the mass of a SMBH and physical properties of the bulge component of its host galaxy (e.g., Kormendy & Ho 2013), such as luminosity, velocity dispersion, and stellar mass.…”