MeerKAT

Abstract:

VANDELS is an ESO Public Spectroscopic Survey designed to build a sample of high-signal-to-noise ratio, medium-resolution spectra of galaxies at redshifts between 1 and 6.5. Here we present the final Public Data Release of the VANDELS Survey, comprising 2087 redshift measurements. We provide a detailed description of sample selection, observations, and data reduction procedures. The final catalogue reaches a target selection completeness of 40% at iAB = 25. The high signal-to-noise ratio of the spectra (above 7 in 80% of the spectra) and the dispersion of 2.5 Å allowed us to measure redshifts with high precision, the redshift measurement success rate reaching almost 100%. Together with the redshift catalogue and the reduced spectra, we also provide optical mid-infrared photometry and physical parameters derived through fitting the spectral energy distribution. The observed galaxy sample comprises both passive and star forming galaxies covering a stellar mass range of 8.3 < Log(M∗/M⊙) < 11.7.

Abstract:

We present the radio and X-ray monitoring campaign of the 2019/2020 outburst of MAXI J1348-630, a new black hole X-ray binary (BH XRB) discovered in 2019 January. We observed MAXI J1348-630 for ∼14 months in the radio band with MeerKAT and the Australia Telescope Compact Array, and in the X-rays with MAXI and Swift/XRT. Throughout the outburst, we detected and tracked the evolution of compact and transient jets. Following the main outburst, the system underwent at least four hard-state-only re-flares, during which compact jets were again detected. For the major outburst, we observed the rise, quenching and reactivation of compact jets, as well as two single-sided discrete ejecta travelling away from the BH, launched ∼2 months apart. These ejecta displayed the highest proper motion (≳100 mas d-1) ever measured for an accreting BH binary. From the jet motion, we constrain the ejecta inclination and speed to be ≤46° and ≥0.69 c, and the opening angle and transverse expansion speed of the first component to be ≤6° and ≤0.05 c. We also infer that the first ejection happened at the hard-to-soft state transition, before a strong radio flare, while the second ejection was launched during a short excursion from the soft to the intermediate state. After travelling with constant speed, the first component underwent a strong deceleration, which was covered with unprecedented detail and suggested that MAXI J1348-630 could be located inside a low-density cavity in the interstellar medium, as already proposed for XTE J1550-564 and H1743-322.