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--- evn:evn_science [2018/09/12 09:15] – antonis
+++ evn:evn_science [2018/09/12 09:19] – [Gravitationally-lensed radio arcs observed with global VLBI] antonis
@@ Line 61: / Line 61: @@
 rms is 41 μJy/beam and the peak surface brightness is 2.9 mJy/beam. The restored beam is 5.5x1.8
 mas, and is shown within the white box in the bottom-hand corner.
+Spingola et al. (2018) analysed these observations and identified lensed emission corresponding to the same source component, providing a very large number of constraints on the mass model that also sampled a large radial and tangential extent. When performing the mass modelling of this system, they found a discrepancy between the observed and predicted positions of the lensed images, with an average position rms of the order of 3 mas, which is much larger that the measurement errors (40 μas on average). A possible explanation for the offset between the observed and model-predicted positions is the presence of some additional mass structure (e.g. Metcalf & Madau 2001). However, since the lensing galaxy lies in a small group of galaxies, it is not clear whether this extra mass is in the form of sub-haloes within the lens or along the line of sight, or from a more complex halo for the galaxy group. Furthermore, the lens mass model suggests an inner density slope for the main lensing galaxy that is steeper than isothermal. This is consistent with studies of other low-mass early-type satellite galaxies in dense environments, and is in agreement with the two-phase galaxy formation scenario (Guo & White 2008).
 ===== The Repeating Fast Radio Burst FRB 121102 as seen on milliarcsecond angular scales =====