A new class of radio source, the so-called Odd Radio Circles (ORCs), havebeen discovered by recent sensitive, large-area radio continuum surveys. Thedistances of these sources have so far relied on photometric redshifts ofoptical galaxies found at the centers of or near the ORCs. Here we presentGemini rest-frame optical spectroscopy of six galaxies at the centers of, orpotentially associated with, the first five ORC discoveries. We supplement thiswith Legacy Survey imaging and Prospector fits to their griz+W1/W2 photometry.Of the three ORCs with central galaxies, all lie at distances (z = 0.27-0.55)that confirm the large intrinsic diameters of the radio circles (300-500 kpc).The central galaxies are massive ($M_*\sim10^{11}M_\odot$), red, unobscuredellipticals with old ($\gtrsim$1~Gyr) stellar populations. They have LINERspectral types that are shock- or AGN-powered. All three host low-luminosity,radio-quiet AGN. The similarity of their central galaxies are consistent with acommon origin, perhaps as a blastwave from an ancient starburst. The other twoORCs are adjacent and have no prominent central galaxies. However, the z=0.25disk galaxy that lies between them hosts a Type 2, moderate-luminosity AGN.They may instead be the lobes of a radio jet from this AGN.

We present a measurement of the low-mass quiescent size-mass relation atCosmic Noon (1<z<3) from the JWST PRIMER and UNCOVER treasury surveys, whichhighlight two distinct classes of quiescent galaxies. While the massivepopulation is well studied at these redshifts, the low-mass end has beenpreviously under-explored due to a lack of observing facilities with sufficientsensitivity and spatial resolution (in the rest-frame near-IR). We select aconservative sample of robust low-mass quiescent galaxy candidates usingrest-frame UVJ colors and specific star formation rate criteria and measuregalaxy morphology in both rest-frame UV/optical wavelengths (F150W) andrest-frame near-infrared (F444W). We confirm an unambiguous "flattening" of thelow-mass quiescent size-mass relation, which results from the separation of thequiescent galaxy sample into two distinct populations at$\log(M_\star/M_\odot)\sim10.3$: low-mass quiescent galaxies that are notablyyounger and have disky structures, and massive galaxies with prolatemorphologies and older median stellar ages. These separate populations implymass quenching dominates at the massive end while other mechanisms, such asenvironmental or feedback-driven quenching, form the low-mass end. This stellarmass dependent slope of the quiescent size-mass relation could also indicate ashift from size growth due to star formation (low masses) to growth via mergers(massive galaxies). The transition mass between these two populations alsocorresponds with other dramatic changes in galaxy evolutions (e.g.star-formation efficiency, dust obscuration, and stellar-halo mass ratios),further highlighting the stark dichotomy between low-mass and massive galaxyformation.

(abridged) We present the newly acquired data for an AstroSat/UVIT fieldcentered on a face-on spiral starburst galaxy UGC 10420, located in the clusterAbell 2199. We have analysed the FUV data for this field along with thearchival data from the Galex mission, optical photometric data from the SDSS,and low-frequency radio data from the LoTSS survey, respectively. The starswere separated from the galaxies using the SDSS pipeline classification, whilethe spectroscopic redshifts available for 35% of the detected UVIT sources wereused to identify member galaxies of the cluster Abell 2199. We find that (a)the non-cluster galaxies are on average fainter than the cluster galaxies atfixed magnitude, (b) stars and galaxies are indistinguishable in the r vs NUV-rplane, and (c) bright stars are ~1.5 mag bluer than the galaxies in the FUV-rvs NUV-r colour-colour plane. Besides UGC 10420 which is the only known clustergalaxy with an extended-UV disk, we identify five more galaxies with asymmetricFUV morphology and extended radio emission in this field. All the asymmetricmember galaxies of Abell 2199, lie within the virial boundaries of the cluster.This observation, together with the fact that these asymmetric cluster galaxieshave low-frequency radio tails or FUV emission pointing away from the clustercentre leads us to hypothesise that these galaxies are likely undergoingram-pressure stripping (RPS) under the influence of cluster-environment relatedmechanisms. A comparison of optical and FUV star formation rate of UVITdetected galaxies shows enhanced star formation in half of the RPS candidates,suggesting that environment-related mechanisms may lead to a burst of starformation in RPS galaxies. Our analysis indicates the presence of at least twomore groups or clusters at z~0.077 and 0.260, coincident with Abell 2199 alongthe line of sight of the field of view studied here.