X-ray binaries are stellar systems composed of a compact object (either a stellar-mass black hole or a neutron star) and a donor star that transfers mass to the former. Outflows represent fundamental physical phenomena to understand accretion processes in these systems. Black holes show three types of outflows: radio-jets and optical winds during the hard accretion states, and highly ionised winds observed in X-rays during the soft states. The black hole transient MAXI J1820+070 showed optical winds with velocities up to 1800 km/s during the hard state of its 2018-2019 outburst. In this work we present the discovery of infrared winds that are present throughout the entire outburst of the black hole, that is, during both hard and soft states. This represents the first detection of a state-independent wind in a black hole transient. Furthermore, this near-infrared wind shows similar kinetic properties to the optical one, suggesting that we are observing the same wind, whose visibility varies as a function of the accretion state. This discovery represents a new milestone in our understanding of accretion and its associated outflows in stellar-mass black holes.
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An eclipse, a superconjunction, and the last meteor shower of the year: Geminids 2020
During the nights of 12th and 13th of December we will enjoy the peak of the Geminid meteor shower. This will be broadcast live from the Teide Observatory (Tenerife) and from the Roque de los Muchachos Observatory ( La Palma) via the sky-live.tv channel, with the collaboration with the Energy Efficiency Labs (EELabs project of the Instituto de Astrofísica de Canarias (IAC) and the Programme of Astronomical Outreach of SODEPAL and the Innovation Service of the Cabildo Insular of La Palma. During the past decade the Geminids have always bid farewell to the year by producing over 100 meteors
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An ionised bubble powered by a proto-cluster at z = 6.5
We show herein that a proto-cluster of Lyα emitting galaxies, spectroscopically confirmed at redshift 6.5, produces a remarkable number of ionising continuum photons. We start from the Lyα fluxes measured in the spectra of the sources detected spectroscopically. From these fluxes we derive the ionising emissivity of continuum photons of the proto-cluster, which we compare with the ionising emissivity required to reionise the proto-cluster volume. We find that the sources in the proto-cluster are capable of ionising a large bubble, indeed larger than the volume occupied by the proto-cluster
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