27 research outputs found
Flares, wind and nebulae: the 2015 December mini-outburst of V404 Cygni
After more than 26 years in quiescence, the black hole transient V404 Cyg went into a luminous outburst in June 2015, and additional activity was detected in late December of the same year. Here, we present an optical spectroscopic follow-up of the December mini-outburst, together with X-ray, optical and radio monitoring that spanned more than a month. Strong ïŹares with gradually increasing intensity are detected in the three spectral ranges during the ⌠10 days following the Swift trigger. Our optical spectra reveal the presence of a fast outïŹowing wind, as implied by the detection of a P-Cyg proïŹle (He iâ5876 ËA) with a terminal velocity of ⌠2500 kmsâ1 . Nebularlike spectra â with an H α equivalent width of ⌠500 ËA â are also observed. All these features are similar to those seen during the main June 2015 outburst. Thus, the fast optical wind simultaneous with the radio jet is most likely present in every V404 Cyg outburst. Finally, we report on the detection of a strong radio ïŹare in late January 2016, when X-ray and optical monitoring had stopped due to Sun constraints
AMI-CL J0300+2613: a Galactic anomalous-microwave-emission ring masquerading as a galaxy cluster
Large scale structure and cosmolog
State of the worldâs plants and fungi 2020
Kewâs State of the Worldâs Plants and Fungi project provides assessments of our current knowledge of the diversity of plants and fungi on Earth, the global threats that they face, and the policies to safeguard them. Produced in conjunction with an international scientific symposium, Kewâs State of the Worldâs Plants and Fungi sets an important international standard from which we can annually track trends in the global status of plant and fungal diversity