Astronomers Detect Regular Rhythm of Radio Waves From Outside Our Galaxy

A team of astronomers, including researchers at MIT, has picked up on a curious, repeating rhythm of fast radio bursts emanating from an unknown source outside our galaxy, 500 million light years away.

Fast radio bursts, or FRBs, are short, intense flashes of radio waves that are thought to be the product of small, distant, extremely dense objects, though exactly what those objects might be is a longstanding mystery in astrophysics. FRBs typically last a few milliseconds, during which time they can outshine entire galaxies.

Since the first FRB was observed in 2007, astronomers have cataloged over 100 fast radio bursts from distant sources scattered across the universe, outside our own galaxy. For the most part, these detections were one-offs, flashing briefly before disappearing entirely. In a handful of instances, astronomers observed fast radio bursts multiple times from the same source, though with no discernible pattern.

This new FRB source, which the team has cataloged as FRB 180916.J0158+65, is the first to produce a periodic, or cyclical pattern of fast radio bursts. The pattern begins with a noisy, four-day window, during which the source emits random bursts of radio waves, followed by a 12-day period of radio silence.

The astronomers observed that this 16-day pattern of fast radio bursts reoccurred consistently over 500 days of observations.

“This FRB we’re reporting now is like clockwork,” says Kiyoshi Masui, assistant professor of physics in MIT’s Kavli Institute for Astrophysics and Space Research. “It’s the most definitive pattern we’ve seen from one of these sources. And it’s a big clue that we can use to start hunting down the physics of what’s causing these bright flashes, which nobody really understands.”

Masui is a member of the CHIME/FRB collaboration, a group of more than 50 scientists led by the University of British Columbia, McGill University, University of Toronto, and the National Research Council of Canada, that operates and analyzes the data from the Canadian Hydrogen Intensity Mapping Experiment, or CHIME, a radio telescope in British Columbia that was the first to pick up signals of the new periodic FRB source.

The CHIME/FRB Collaboration has published the details of the new observation today (June 17, 2020) in the journal Nature.

A radio view
In 2017, CHIME was erected at the Dominion Radio Astrophysical Observatory in British Columbia, where it quickly began detecting fast radio bursts from galaxies across the universe, billions of light years from Earth.

CHIME consists of four large antennas, each about the size and shape of a snowboarding half-pipe, and is designed with no moving parts. Rather than swiveling to focus on different parts of the sky, CHIME stares fixedly at the entire sky, using digital signal processing to pinpoint the region of space where incoming radio waves are originating.

From September 2018 to February 2020, CHIME picked out 38 fast radio bursts from a single source, FRB 180916.J0158+65, which the astronomers traced to a star-churning region on the outskirts of a massive spiral galaxy, 500 million light years from Earth. The source is the most active FRB source that CHIME has yet detected, and until recently it was the closest FRB source to Earth

Source: scitechdaily

اكتشف تلسكوب CHIME اللاسلكي الكندي مصدرا غريبا من الإشارات اللاسلكية الكونية ذات طبيعة غامضة.

وقال العلماء الكنديون في مقال نشرته مجلة Nature إن مصدر الإشارات لا يمكن أن تفسره أية نظرية كونية وفلكية سارية المفعول، لأن الإشارات التي يولدها تتكرر بعد كل 16 يوما أرضيا. ونقلت المجلة عن العالم الفلكي الفيزيائي في جامعة نيفادا الأمريكية، جان بين، قوله إن هناك 50 نظرية تصف طبيعة الإشارات اللاسلكية الكونية، لكن كلها تعجز عن إيضاح طبيعة تلك الإشارات المتكررة الغامضة.

وقال الفلكي إن تلك الإشارات عبارة عن نبضات لاسلكية قوية قصيرة ذات تشكيلة غريبة يبعد مصدرها مسافة هائلة عن الأرض. ويمكن أن يقول العلماء في الوقت الحاضر إن تلك الإشارات التي أطلقوا عليها تسمية “إشارات سكان كواكب أخرى” لديها بضع ميزات تجمع بينها وهي تكرارها المنتظم وقوتها الكبيرة ومسافة هائلة تفصل بين مصادرها والأرض. وافترض العلماء أولا أن كوارث كونية، بما فيها اندماج نجمين نيترونيين، أو ثقبين أسودين يمكن أن تولدها. وتوصلوا عام 2017 إلى استنتاج يفيد بأن هذا الافتراض خاطئ. وذلك بعد أن اكتشف تلسكوب CHIME اللاسلكي الكندي عام 2017 مصدرا آخر للإشارات اللاسلكية القوية المتكررة في نقطة من السماء كانت الإشارات المتكررة بعد 16 يوما قد أتت منها واكتشفت عام 2012. وتم اكتشاف مصدر لتلك الإشارات في كوكبة كاسيوبيا التي تبعد عن الأرض 500 مليون سنة ضوئية.

المصدر: al-sharq