light echoes – Astronomy Now

Rings around a black hole from X-ray echoes off interstellar dust

8 August 2021 Astronomy Now

An X-ray outburst from a binary black hole system creates spectacular “light echoes” as the radiation bounces off intervening dust clouds, shedding light on the hole’s activity and the nature of the smoke-like dust grains.

X-ray echoes of a shredded star provide close-up of monster black hole

23 June 2016 Astronomy Now

Some 3.9 billion years ago in the heart of a distant galaxy, the intense tidal pull of a monster black hole shredded a star that passed too close. After X-rays produced in this event first reached Earth on 28 March 2011, scientists concluded that the outburst, now known as Swift J1644+57, also represented the sudden flare-up of a previously inactive black hole.

Light echoes give clues to young star’s protoplanetary disc

27 April 2016 Astronomy Now

Protoplanetary discs are ‘doughnuts’ of gas and dust surrounding young stars, the sites where planets form over the course of millions of years. Researchers studying the one-million-year-old infant star YLW 16B, some 400 light-years from Earth, were able to determine the distance from the star to the inner rim of its surrounding protoplanetary disc by observing its light echo.