Sagittarius A*- Our Nearest BlackHole | Do You Know Why It Is Quiet?

Sagittarius A* is the nearest supermassive black hole to the sun and provides a reasonable opportunity to find out how the mystifying giant works.

We all have watched “Interstellar,” the incredible movie. The astronauts get drowned into the black hole to explore the new upside-down universe where the gravitational attraction was too strong that light could not escape. Even astronauts got drifted so strong by an invisible, powerful force around that black hole, in the movie.

The recent benchmark stimulated image of the black hole “Powei” has also proved its monstrous look all around the world, hence given the evidence of how gravity and other forces workaround that giant thing.

Using the Event Horizon Telescope, scientists obtained an image of the black hole at the center of galaxy M87, outlined by emission from hot gas swirling around it under the influence of strong gravity near its event horizon. Credits: Event Horizon Telescope collaboration et al.

Researchers accept that at the core of every galaxy exists a supermassive black hole that incorporates our apparently non-chaotic Milky Way galaxy. They said, while the black holes in other galaxies are exceptionally dynamic with a large amount of matter falling into it in the process of feeding, the one in the Milky Way is relatively quiet in nature.

The recent study done by them opens answer to the question of why is it quiet in nature. The black hole at the centre of our galaxy is quite silent in nature.

The SOFIA Has Discovered Why It Is So

NASA owned Stratospheric Observatory developed for Infrared Astronomy (SOFIA), has a device called the High-resolution Airborne Wideband Camera-Plus (HAWC+) which is measuring a powerful magnetic field around the centre of the Milky Way galaxy.

HAWC: The Game-Changer

HAWC was constructed at the University of Chicago; the NASA’s Jet Propulsion Laboratory led the HAWC+ upgrade. It is intended to cover the parts of the infrared spectrum that is unavailable to the ground-based observatories and crucial for studies of astronomical sources with temperatures ranging from tens and hundreds of degrees Kelvin.

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It was also designed to accommodate advances in technology and changing science needs. HAWC+, an advanced version of HAWC, is seven times more sensitive to extended emission fifty times more sensitive to point sources. It also has a facility of providing ten times better areal resolution. It covers five wavelength bands instead of one and hence proved a better instrument to take measurements.

Do You Know Why Sagittarius A* is Quiet? | ScienceMonk
A close look at HAWC+ before installation. Image credits: NASA/SOFIA

Strong Magnetic Force Playing Wild

Scientists said that these invisible forces might be so strong that they may help in the evolution of matter millions of years ago. The team said that these forces even influence the motion of charged particles in space.
It is believed that magnetic forces can explain, why in other galaxies the supermassive black holes are much louder than its counterpart at the Milky Way’s core. Though gravity in a black hole is easily understood, the impact of its magnetic field on the solar system often remains a puzzle.

HAWC+ results also imply that perhaps the magnetic field is sufficiently strong to restrict the dynamic motion of gases.

Do You Know Why Sagittarius A* is Quiet? | ScienceMonk
Streamlines are depicting magnetic fields spread over the colour image of the dusty loop around the Milky Way’s massive black hole. Image credit: NASA/SOFIA/Hubble Space Telescope.

The strong gravitational pull of the central black hole of the Milky Way, known as Sagittarius A*, dominates the galaxy’s core. Being the nearest to our solar system gives a lot of chances to study the role of the magnetic field and its interaction with matter.

Do You Know Why Sagittarius A* is Quiet? | ScienceMonk
A close look at the black hole Sagittarius A* in the Milky Way galaxy seen in spectra of X-rays by NASA’s Chandra Observatory. The blue-coloured spots are hot gas emitting rays which are being pulled towards the black hole.

In particular, as matter crashes into black holes, the dark giants produce high energy radiation that confirms their existent. Compared to black holes seen in other galaxies, nevertheless, the Milky Way’s heart is surprisingly quiet, transmitting far less radiation than anticipated.

Knowing how black holes associated with their magnetic fields can aid researchers to grasp the difference between active and quiet black holes. Magnetic fields aren’t easy to see, and haven’t been imaged like visible, infrared signals in space have been. So it’s heading on a landmark when the HAWC+ tool went on to pick up polarized far-infrared light that is produced by space dust which is invisible to the human eye.

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To study the invisible magnetic field around Sagittarius A*, researchers tracked polarized far-infrared light emitted by dust particles around the black giant. The wavelength of far-infrared radiation emitted by dust grains is 40-300 microns. This spectral region is accessible to aircraft operating within the stratosphere.

The team, looking at dust particles line up perpendicular to magnetic fields, were able to trace the shape and conclude the power of the magnetic field across the black hole. When merged with the mid and far-infrared images of Sagittarius A* disclosed the direction of the magnetic field.

“While some of the material from the surrounding ring of gas and dust is falling toward the black hole, the magnetic field also directs material away from the hungry giant,”said researchers. “The spiral shape of the magnetic field channels the gas into an orbit around the black hole,” said the principal investigator Darren Dowell, of NASA’s Jet Propulsion Laboratory in Pasadena, California.“This could explain why our black hole is quiet while others are active,” added Dowell, lead author of a new study reporting the SOFIA results.

Sagittarius A* is the nearest supermassive black hole to the sun and provides a reasonable opportunity to find out how the mystifying giant works. Cosmologists plan to use this fresh stream of information to outline the shape and assess the power of the unseen magnetic field around the centre, which could assist to better image black holes.

“This is one of the first instances we can see how magnetic fields and interstellar matter interact with each other,” John Schmelz, a co-author on a paper and astrophysicist at NASA Ames Research Centre in California, noted in a statement. HAWC+ is a game-changer”

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What kind of sounds like a spiral-shaped magnetic field channel around the black hole might be a significant discovery that can help address most of the astrophysicists’ questions about all this? For example, why the black hole in the Milky Way’s main portion is comparatively weak while others are much brighter.

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