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The 3C 220.3 system is a rare case of a foreground narrow-line radio galaxy (“galaxy A,” z _A = 0.6850) lensing a background submillimeter galaxy ( z _SMG = 2.221). New spectra from MMT/Binospec confirm that the companion galaxy (“galaxy B”) is part of the lensing system with z _B = 0.6835. New three-color Hubble Space Telescope (HST) data reveal a full Einstein ring and allow a more precise lens model. The new HST images also reveal extended emission around galaxy A, and the spectra show extended [O ii ] emission with irregular morphology and complex velocity structure. All indications are that the two lensing galaxies are a gravitationally interacting pair. Strong [O ii ] emission from both galaxies A and B suggests current star formation, which could be a consequence of the interaction. This would indicate a younger stellar population than previously assumed and imply smaller stellar masses for the same luminosity. The improved lens model and expanded spectral energy distributions have enabled better stellar mass estimates for the foreground galaxies. The resulting dark matter fractions are ∼0.8, which are higher than previously calculated. Deeper Chandra imaging shows extended X-ray emission but no evidence for an X-ray point source associated with either galaxy. The detection of X-rays from the radio lobes of 3C 220.3 allows an estimate of ∼3 nT for the magnetic fields in the lobes, a factor of ∼3 below the equipartition fields, as is typical for radio galaxies.

While supermassive black holes are ubiquitous features of galactic nuclei, only a small minority are observed during episodes of luminous accretion. The physical mechanism(s) driving the onset of fueling and ignition in these active galactic nuclei (AGN) are still largely unknown for many galaxies and AGN-selection criteria. Attention has focused on AGN triggering by means of major galaxy mergers gravitationally funneling gas toward the galactic center, with evidence both for and against this scenario. However, several recent studies have found that radio-loud AGN overwhelmingly reside in ongoing or recent major galaxy mergers. In this study, we test the hypothesis that major galaxy mergers are important triggers for radio-loud AGN activity in powerful quasars during cosmic noon (1 ≲ z ≲ 2). To this end, we compare Hubble Space Telescope WFC3/IR observations of the z > 1 3CR radio-loud broad-lined quasars to three matched radio-quiet quasar control samples. We find strong evidence for major-merger activity in nearly all radio-loud AGN, in contrast to the much lower merger fraction in the radio-quiet AGN. These results suggest major galaxy mergers are key ingredients in launching powerful radio jets. Given many of our radio-loud quasars are blue, our results present a possible challenge to the “blowout” paradigm of galaxy evolution models in which blue quasars are the quiescent end result following a period of red quasar feedback initiated by a galaxy merger. Finally, we find a tight correlation between black hole mass and host galaxy luminosity for these different high-redshift AGN samples that is inconsistent with those observed for local elliptical galaxies.

During an expedition in 2016, a rich fauna of freshwater gastropods of the family Tateidae Thiele, 1925 was discovered on the ultramafic terrains of the Southeast of New Caledonia (NC). Hitherto, only three of the 62 known NC family members were reported from this type of bedrock. With less than 1.5 mm in length, many of the new species are particularly small. In order to establish a methodological setup for the description and phylogenetic analyses of these new species, we here describe Viriiella touaouroua gen. et sp. nov. and assess its relationships based on three gene fragments. Viriiella is morphologically well defined and resembles Fluviopupa Pilsbry, 1911 not present in NC. In the phylogenetic analyses, though, Viriiella appeared as a member of the Hemistomia-clade, the NC tateids occurring on non-ultramafic terrain. However, Viriiella had the longest branch and, sister group to different genera in maximum likelihood and Bayesian analyses, its position was unstable, probably an artifact due to long-branch attraction. Considering that Viriiella does not share the defining character states of Hemistomia s. lat., it may well be possible that inclusion of more related genera will show that the new taxa share a most recent common ancestor with the Hemistomia-clade, but as sister group.