Heavy-element production in a compact object merger observed by JWST.

The mergers of binary compact objects such as neutron stars and black holes are of central interest to several areas of astrophysics, including as the progenitors of gamma-ray bursts (GRBs)1, sources of high-frequency gravitational waves (GWs)2 and likely production sites for heavy-element nucleosynthesis by means of rapid neutron capture (the r-process)3. Here we present observations of the exceptionally bright GRB 230307A. We show that GRB 230307A belongs to the class of long-duration GRBs associated with compact object mergers4-6 and contains a kilonova similar to AT2017gfo, associated with the GW merger GW170817 (refs. 7-12). We obtained James Webb Space Telescope (JWST) mid-infrared imaging and spectroscopy 29 and 61 days after the burst. The spectroscopy shows an emission line at 2.15 microns, which we interpret as tellurium (atomic mass A = 130) and a very red source, emitting most of its light in the mid-infrared owing to the production of lanthanides. These observations demonstrate that nucleosynthesis in GRBs can create r-process elements across a broad atomic mass range and play a central role in heavy-element nucleosynthesis across the Universe.

A structured jet explains the extreme GRB 221009A.

Long-duration gamma-ray bursts (GRBs) are powerful cosmic explosions, signaling the death of massive stars. Among them, GRB 221009A is by far the brightest burst ever observed. Because of its enormous energy (Eiso ≈ 1055 erg) and proximity (z ≈ 0.15), GRB 221009A is an exceptionally rare event that pushes the limits of our theories. We present multiwavelength observations covering the first 3 months of its afterglow evolution. The x-ray brightness decays as a power law with slope ≈t-1.66, which is not consistent with standard predictions for jetted emission. We attribute this behavior to a shallow energy profile of the relativistic jet. A similar trend is observed in other energetic GRBs, suggesting that the most extreme explosions may be powered by structured jets launched by a common central engine.

Tuberculosis of the spine--Prospective neurological and patient reported outcome study.

OBJECTIVE: To prospectively investigate the rate of neurological recovery and patient reported outcome of tuberculosis (TB) spine patients following surgery at a tertiary referral hospital. TB spine remains a major cause of neurological impairment in the developing world fuelled by poor socio-economic conditions and HIV co-infection. Although numerous retrospective studies are available, there is a paucity of prospective data regarding rate of neurological improvement and patient reported outcome. METHODS: Twenty adult patients were prospectively recruited. The average age was 44.5 years. Half had co-existent HIV infection. All patients underwent decompressive surgery utilising a variety of anterior and posterior procedures. All received a minimum of 9 months TB medication. They were followed up at 4, 8, 12, 26 and 52 weeks post operatively. Neurological status was monitored by Nurick, mJOA and ASIA systems. Patient reported outcome was monitored by SF36 questionnaires at all-time points. RESULTS: All patients improved neurologically including 4 ASIA A's. By last follow up, 17 could walk as opposed to 5 pre-op. The Nurick average score improved from 5.5 to 1.9 and the mJOA lower limb score 1.8-5.5. The SF36 improved from 31 to 62 over the year with the biggest gains occurring after 3 months. This was confirmed in all domains except pain and social, which improved earlier. CONCLUSIONS: There is a positive prognosis for neurological outcome in TB spine following a variety of surgical decompressive procedures and medical therapy. The majority of the recovery occurs after the 3 months post-operative mark.

A possible relativistic jetted outburst from a massive black hole fed by a tidally disrupted star.

Gas accretion onto some massive black holes (MBHs) at the centers of galaxies actively powers luminous emission, but most MBHs are considered dormant. Occasionally, a star passing too near an MBH is torn apart by gravitational forces, leading to a bright tidal disruption flare (TDF). Although the high-energy transient Sw 1644+57 initially displayed none of the theoretically anticipated (nor previously observed) TDF characteristics, we show that observations suggest a sudden accretion event onto a central MBH of mass about 10(6) to 10(7) solar masses. There is evidence for a mildly relativistic outflow, jet collimation, and a spectrum characterized by synchrotron and inverse Compton processes; this leads to a natural analogy of Sw 1644+57 to a temporary smaller-scale blazar.