July 7, 2022


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Astronomers confirm the discovery of the first moving arc of the micro-lens |  urania

Astronomers confirm the discovery of the first moving arc of the micro-lens | urania

An international research team, including astronomers from the Astronomical Observatory of the University of Warsaw, has determined the mass of the invisible object with great accuracy, using the phenomenon of microgravity.

April 18, 2019 Gaia space probe Astronomers around the world have warned of a very bright but fleeting event in the sky: microgravity Gaia19bld. The temporary and random alignment between two unrelated star systems produced double background images and gave scientists the first opportunity to observe the arc-shaped images moving in real time, unlocking key information. other notes Photometry I Spectroscopy It was made by the instruments of the Las Cumbres Observatory (LCO) that accurately determined the angular between the brackets. In parallel, the Pioneer instrument in the interferometer Very Large Telescope (VLT) Watch the images evolve over time during the climax of the event. Combining all of this data made it possible for the first time to quantify microlens body mass with unprecedented accuracy.

Microgravitational lensing is a powerful technique for measuring the mass of isolated, faint, or non-luminous objects in Milky Way. In a galactic microlens, a massive anterior object (“lens”) intersects the background star’s line of sight and divides its disk-shaped image into multiple anamorphic images. The separation of these images of stellar-mass lenses is so small that astronomers typically cannot distinguish them, and instead measure the overall increase in total light received from the source (called magnification) as star systems align, and then exceed. The clear images produced by the stellar lens have only been discovered once before, but their movement in real time has not yet been observed, although it was predicted several decades ago. Because a fine lens does not depend on the light emitted by the lenses themselves, it can be used to detect distant planets (even those without a host star), faint Brown I white dwarfs, And neutron stars I stellar mass black holes.

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In most cases, a combination of optical and spectroscopic observations is required to accurately measure the mass of microlensing lenses.

W Article – Commodity Published in the Journal of Astronomy and Astrophysics, LCO’s Dr. Etienne Bachelet describes the use of spectroscopic and imaging observations from LCO to calculate mass and distance to a Gaia19bld lens. During this event, low- and high-resolution spectroscopy was obtained from many sites around the world. astronomers from University of Warsaw Astronomical Observatory.

Gaia19bld is a stunning demonstration of the multifaceted observational capabilities of the micro-lens phenomenon. Using two space satellites, ground-based telescopes, a network of smaller telescopes, and high-resolution spectroscopy and interferometry, it was possible to accurately determine the characteristics of the lens and the source, which was not possible with either of these two channels separately.

We decided to look closely at this phenomenon, called Gaia19bld, with the hope of very strong signal amplification in the coming days. We pointed ground-based telescopes on different continents and the Spitzer Space Telescope at the star – says Krzysztof Rybicki, a doctoral student at OA Warsaw University, lead author of the analysis and one of the publishing on the Gaia19bld phenomenon.

This work demonstrates the possibility of spectral monitoring of microlensing events. It allows for accurate characterization of the source star parameters, which are necessary to discover the physical properties of the hidden lens system. This is especially useful for events in galaxy disk, where the distance to the source and how dark it is dusted is not well known. The methods described in this paper are expected to be routinely used in the era of the next generation of whole-sky surveys that are currently being developed. In particular, the Paleolithic Survey of Space and Time will discover thousands of events each year that will require spectroscopic observations to better characterize their properties and ultimately advance our understanding of faint objects across the Milky Way.

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As Krzysztof Rebicki adds: For the first time, we were able to record not only two separate images of the source, but also change their position during lensing. Such an effect results directly from Albert Einstein’s general theory of relativity and was predicted by the professor more than 30 years ago. Bohdan Baczinski, prominent Polish astronomer and graduate of the University of Warsaw.

Agnieszka Nowak

more information:

Source: LCO

In the illustration: an image of an elliptical galaxy LRG 3-757, an example of galactic light distorted by a gravitational lensing. Source: ESA/Hubble, NASA.