Radio galaxy phenomenon is directly connected to mass accreting, spinning supermassive black holes found in the active galactic nuclei (AGN). It is still unclear how the collimated jets of relativistic plasma on hundreds to thousands of kpc scale form, and why nearly always they are launched from the nuclei of bulge dominated elliptical galaxies and not flat spirals. Here we present the discovery of giant radio source J2345-0449 (z = 0.0755), a clear and extremely rare counter example where relativistic jets are ejected from a luminous and massive spiral galaxy on scale of ∼ 1.6 Mpc, the largest known so far. Extreme physical properties observed for this bulgeless spiral host, such as its high optical and infra-red luminosity, large dynamical mass, rapid disk rotation, and episodic jet activity are possibly the results of its unusual formation history, which has also assembled, via gas accretion from a disk, its central black hole of mass > 2 × 10 8 M ⊙ . The very high mid-IR luminosity of the galaxy suggests that it is actively forming stars and still building a massive disk. We argue that the launch of these powerful jets is facilitated by an advection dominated, magnetized accretion flow at low Eddington rate onto this unusually massive (for a bulgeless disk galaxy) and possibly fast-spinning central black hole. Therefore, J2345-0449 is an extremely rare, unusual galactic system whose properties challenge -2the standard paradigms for black hole growth and formation of relativistic jets in disk galaxies. Thus, it provides fundamental insight into accretion diskrelativistic jet coupling processes.

We present a study of the radio properties of 870 µm-selected submillimetre galaxies (SMGs), observed at high resolution with ALMA in the Extended Chandra Deep Field South. From our initial sample of 76 ALMA SMGs, we detect 52 SMGs at > 3σ significance in VLA 1400 MHz imaging, of which 35 are also detected at > 3σ in new 610 MHz GMRT imaging. Within this sample of radio-detected SMGs, we measure a median radio spectral index α 1400 610 = −0.79 ± 0.06, (with inter-quartile range α = [−1.16, −0.56]) and investigate the far-infrared/radio correlation via the parameter q IR , the logarithmic ratio of the rest-frame 8-1000 µm flux and monochromatic radio flux. Our median q IR = 2.56 ± 0.05 (inter-quartile range q IR = [2.42, 2.78]) is higher than that typically seen in single-dish 870 µm-selected sources (q IR ∼ 2.4), which may reflect the fact that our ALMA-based study is not biased to radio-bright counterparts, as previous samples were. Finally, we search for evidence that q IR and α evolve with age in a co-dependent manner, as predicted by starburst models: the data populate the predicted region of parameter space, with the stellar mass tending to increase along tracks of q IR versus α in the direction expected, providing the first observational evidence in support of these models.

New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622–4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100× larger than during its dormant state. The X-ray flux one month after reactivation was at least 800× larger than during quiescence, and has been decaying exponentially on a 111 ± 19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3–6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6–8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation.