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Showing posts from November, 2024

A Bubbly Origin for Odd Radio Circles

   From- Sky & Te;escope  By - Aas Nova  Edited by - Amal Udawatta A radio image of the first odd radio circle to be discovered, ORC-1, with a visible-light image of stars and galaxies forming the background. Jayanne English (U. Manitoba), EMU (ASKAP/CSIRO), MeerKAT, DES (CTIO) Discovered in 2019, odd radio circles (ORCs) are among the newest and most mysterious astrophysical phenomena. New research examines how bubbles blown by black hole jets could create these striking features. ============================================== Stumped by Space ORCs ORCs are faint extragalactic circles of radio emission that appear to be invisible at other wavelengths. As the number of known ORCs slowly climbs, researchers have begun to test possible formation mechanisms. Among the many possibilities are the jets of active galactic nuclei: luminous galactic centers powered by accreting supermassive  black holes. In this hypothesis, active galactic nucleus jets filled with fa...

New Views of Vega’s Dusty Disk

  From - Sky & Telescope By - Colin Stuart Edited by - Amal Udawatta Constant Contact Use. Please leave this field blank. False-color views of the face-on circumstellar disk around Vega from the Hubble (left) and Webb (right) space telescopes. In both images, light from the star itself has been subtracted to create the dark spot at the center. The disk is very smooth, with no evidence of embedded large planets. NASA / ESA / CSA / STScI / S. Wolff, K. Su, A. Gáspár (University of Arizona) Vega, the stellar standout of the constellation Lyra, the Lyre, has long intrigued astronomers. It is one of the brightest stars in the sky, and the glow of all other is measured against it. To say that the circumstellar disk around Vega is vast would be an understatement — it spans about 100 billion miles. That’s more than 1,000 times Earth’s distance from the Sun. High-resolution images reveal the debris disk around Lyra’s brightest star to be exceedingly smooth. If any planets lurk therein, ...

Newfound Stellar Companion May Explain Black Hole System

  From - Sky & Telescope Camille M. Carlisle   By - Camille M. Carlisel  Edited by Amal Udawatta  Constant Contact Use. Please leave this field blank. Artist's concept of the V404 Cygni system, in which a black hole is stealing gas from a nearby star. Astronomers had thought the system was only a binary, but a second star (upper white flash) orbits at a much farther distance. Jorge Lugo The system V404 Cygni is an old favorite with astronomers. The binary contains a 9-solar-mass black hole that’s slurping gas from a star slightly less massive than the Sun. Astronomically speaking, only a hair’s breath separates the pair: 0.14 astronomical unit, or less than half Mercury’s average distance from the Sun. (This is normal for these kinds of systems.) The hot gas swirling down onto the black hole creates an X-ray beacon. In fact, V404 Cygni was the first system of its kind — called a  low-mass X-ray binary , or LMXB, where the “low mass” refers to the companion s...

Bat safety barrier will cost £100m - HS2 chairman

   From - BBC News  By -  Louise Parry  - BBC News, Buckinghamshire Edited by - Amal Udawatta Getty Images The current HS2 chairman asked "did people think about the bats?" when setting the project's budget A special barrier that will be built to protect rare   bats will cost £100m, according to the chairman of HS2 Ltd. Sir Jon Thompson told a rail industry conference the bat protection structure in Buckinghamshire was needed to appease Natural England, as bats are legally protected in the UK. The 1km (0.6 mile) curved barrier will cover the tracks alongside Sheephouse Wood near Calvert in Buckinghamshire, to prevent bats being disturbed by high-speed trains. Sir Jon said there was "no evidence that high-speed trains interfere with bats". "We call it a shed," he said. "This shed, you're not going to believe this, cost more than £100m to protect the bats in this wood." Natural England said it had not required HS2 to "adopt this struct...

A Radio Burst from a Giant "Dead" Galaxy

      From - Sky & telescope  By- Govert Schilling  Edited by - Amal Udawatta     Using the CHIME radio telescope, astronomers detected a three-second flash from a far-off galaxy that contained beat with a surprising regularity. Photo courtesy of CHIME, with background edited by MIT News Exotic magnetars make brief, powerful flashes of radio waves — but a new discovery suggests there may be more than one way to make a magnetar. For the first time ever, astronomers have detected a  fast radio burst  (FRB) in a large elliptical galaxy. The discovery, announced at the FRB2024 conference in Khao Lak, Thailand, supports earlier indications that there are various ways to form the extreme objects that produce these ultra-brief flashes of radio waves. Astronomers first discovered fast radio bursts in 2007, and more than 800 have been observed to date (see S&T’s  September 2022  issue). In just one-thousandth of a second, they radiat...

Black Hole Eats One Star, the Remains Pummel a Second One

     From- Sky &Telescope    By - Monica Young    Edited by - Amal Udawatta This artist’s illustration shows a disk of material (red, orange, and yellow) created after a supermassive black hole (depicted on the right) destroyed a star through intense tidal forces. After a few years, this disk expanded outward until it began intersecting another orbiting object — either a star or a small black hole — around the giant black hole. NASA / CXC / SAO and Soheb Mandhai / The Astro Phoenix In 2019 a supermassive black hole ate a star. It’s incredible that such an incredible event is now commonplace — not in individual galaxies, where such stellar meals happen only every 10,000 to 100,000 years, but in our telescopes, through which astronomers can monitor millions of galaxies to observe their feeding habits.      The crumbs of a supermassive black hole’s stellar meal has revealed the presence of a second star in a close orbit. But in the cour...