Artistic impression of the constant emission of winds produced during the eruption of a black hole in an X-ray beam. Credit: Gabriel Pérez Díaz, SMM (IAC)
Until now, these material streams were only discovered in other wavelength ranges, such as X-rays or the visible, depending on the phase in which the black hole consumes the surrounding material. This study provides the first evidence that the winds are present in the evolution of the eruption, regardless of the phase, and this is a step forward in our understanding of the mysterious processes of accretion on dead mass black holes. The article was just published in Astronomy and Astrophysics Letters, and was chosen as an ‘excellent article’ by the magazine itself.
X-ray binaries, as their name implies, are binary stars that emit strong radiation in X-ray images. They are formed by a compact object, usually a black hole, with a stellar size. Low mass X-ray binaries (LMXB) have companions with masses equal to or less than the mass of the sun. In these systems, the two stars rotate at a distance so small that some of the star’s mass falls into the gravity pit of the black hole, forming a flat disk of material around it. This process is called accretion, and the disk is an accretion disc.
Some X-ray binaries, called transient, change from quiescent states, where the amount of mass applied to the black hole is small and the brightness is too low to detect from the earth, to eruptive states in which the black hole has an increased application level, so that the material in the disk heats up, and values reach between one and ten million degrees Kelvin. During these eruptions, which can last from weeks to several months, the system emits a large stream of X-rays, increasing the brightness by various magnitudes.
We do not yet know exactly what are the physical processes that occur during these deviation episodes. “These systems are places where matter is subjected to gravitational fields that belong to the strongest in the universe, so X-ray binaries are physics laboratories that nature provides us for the study of compact objects, and the behavior of the case around them, ”explains Javier Sánchez Sierras, a pre-doctoral researcher at the IAC and the first author of the article.
One of the most important physical processes that scientists need to understand is the release of material, such as winds, during episode episodes. According to Teo Muñoz Darias, an IAC researcher and co-author of the article, “the study of wines in those systems is a key to understanding accretion processes, because wine can dispel even more matter than is accepted through the black hole. “.
Same wine, different states
The article just published in Astronomy and Astrophysics Letters, which was chosen by the magazine as a “highlight article”, presents the discovery of wines from the black hole MAXI J1820 + 070 in the infrared, during the eruption that lasted place during 2018-2019. Over the past two decades, winds have been observed in X-rays during eruption, so-called in which the radiation emitted by the accretion disk is dominant, with high brightness. More recently, the same group at the IAC has discovered at visible wavelengths winds in the hard state of accretion, which is characterized by the appearance of a jet, which is essentially perpendicular to the accretion disk, and which strongly emits at radio wave lengths.
“In the present study – emphasizes Sánchez Sierras – we have shown the discovery of infrared debris present in both the hard and soft ore states, during the full evolution of the eruption, so that its presence is not dependent on ‘ the accretion status, and this is the first time this type of wind has been observed. ”The researchers were also able to show that the kinematic properties of the wind are very similar to those observed in 2019 in the visible range, reaching speeds up to 1800 km / s .
“These data suggest that the wind is the same for both cases, but its visibility changes wavelength during the evolution of the eruption, which would indicate that the system loses mass as well as angular momentum during the eruption process,” explains Muñoz Darias, These results are very important for the scientists, because they add a new element to the global picture of the wines in these systems, and represent a step forward towards the goal of completing our understanding of the processes of mining on stars. mass of black holes.
Reference: “Near-infrared emission lines follow the state-independent extraction disk wind of the black hole transient MAXI J1820 + 070” by J. Sánchez-Sierras and T. Muñoz-Darias, 28 July 2020, Astronomy & Astrophysics.
DOI: 10.1051 / 0004-6361 / 202038406
