Tag: gamma ray burst

Moving Closer to Understanding of Universe’s Most Powerful Explosions

Good fortune and cutting-edge scientific equipment have allowed scientists to observe a Gamma Ray Burst jet with a radio telescope and detect the polarization of radio waves within it for the first time – moving us closer to an understanding of what causes the universe’s most powerful explosions.

Gamma Ray Bursts (GRBs) are the most energetic explosions in the universe, beaming out mighty jets which travel through space at over 99.9% the speed of light, as a star much more massive than our Sun collapses at the end of its life to produce a black hole. The study was published in Astrophysical Journal Letters.

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Studying the light from Gamma Ray Burst jets as we detect it travelling across space is our best hope of understanding how these powerful jets are formed, but scientists need to be quick to get their telescopes into position and get the best data. The detection of polarized radio waves from a burst’s jet, made possible by a new generation of advanced radio telescopes, offers new clues to this mystery.

The light from this particular event, known as GRB 190114C, which exploded with the force of millions of Suns’ worth of TNT about 4.5 billion years ago, reached NASA’s Neil Gehrels Swift Observatory on Jan 14, 2019.

A rapid alert from Swift allowed the research team to direct the Atacama Large Millimeter/Sub-millimeter Array (ALMA) telescope in Chile to observe the burst just two hours after Swift discovered it. Two hours later the team was able to observe the GRB from the Karl G. Jansky Very Large Array (VLA) telescope when it became visible in New Mexico, USA.

Combining the measurements from these observatories allowed the research team to determine the structure of magnetic fields within the jet itself, which affects how the radio light is polarized. Theories predict different arrangements of magnetic fields within the jet depending on the fields’ origin, so capturing radio data enabled the researchers to test these theories with observations from telescopes for the first time.

The research team, from the University of Bath, Northwestern University, the Open University of Israel, Harvard University, California State University in Sacramento, the Max Planck Institute in Garching, and Liverpool John Moores University discovered that only 0.8% of the jet light was polarized, meaning that jet’s magnetic field was only ordered over relatively small patches – each less than about 1% of the diameter of the jet. Larger patches would have produced more polarized light.

These measurements suggest that magnetic fields may play a less significant structural role in GRB jets than previously thought. This helps us narrow down the possible explanations for what causes and powers these extraordinary explosions.

First author Dr. Tanmoy Laskar, from the University of Bath’s Astrophysics group, said: “We want to understand why some stars produce these extraordinary jets when they die, and the mechanism by which these jets are fuelled – the fastest known outflows in the universe, moving at speeds close to that of light and shining with the incredible luminosity of over a billion Suns combined.

“I was in a cab on my way to O’Hare airport in Chicago, following a visit with collaborators when the burst went off. The extreme brightness of this event and the fact that it was visible in Chile right away made it a prime target for our study, and so I immediately contacted ALMA to say we were going to observe this one, in the hope of detecting the first radio polarization signal.

“It was fortuitous that the target was well placed in the sky for observations with both ALMA in Chile and the VLA in New Mexico. Both facilities responded quickly and the weather was excellent. We then spent two months in a painstaking process to make sure our measurement was genuine and free from instrumental effects. Everything checked out, and that was exciting.

Dr. Kate Alexander, who led the VLA observations, said: “The lower frequency data from the VLA helped confirm that we were seeing the light from the jet itself, rather than from the interaction of the jet with its environment.”

Dr. Laskar added: “This measurement opens a new window into GRB science and the studies of energetic astrophysical jets. We would like to understand whether the low level of polarization measured in this event is characteristic of all GRBs, and if so, what this could tell us about the magnetic structures in GRB jets and the role of magnetic fields in powering jets throughout the universe.”

Professor Carole Mundell, Head of Astrophysics at the University of Bath, added: “The exquisite sensitivity of ALMA and rapid response of the telescopes has, for the first time, allowed us to swiftly and accurately measure the degree of polarization of microwaves from a GRB afterglow just two hours after the blast and probe the magnetic fields that are thought to drive these powerful, ultra-fast outflows.”

The research team plans to hunt for more GRBs to continue to unravel the mysteries of the biggest explosions in the universe.

Part IV – Cycles Within Cycles, Within Cycles and ‘Science Of Cycles’

Here I am writing, then re-writing and then re-writing again. Partly because I find this exploratory research exhilarating, partly because it affirms the direction I chose to follow beginning mostly in 2012. And of course new information which was not available just a few years ago, and then formulating these strings of thought which has brought on a few spattering of “You’re kidding, no way, I thought so, and just plain wow”. Once again, as in my research of the Sun-Earth connection, but to a less noticeable degree, the right hand was not quite sure what the left hand was doing or aware of.

Those of you familiar with my first book “Solar Rain” will remember how I conveyed my unexpected surprise, when I realized how two of our greatest scientific bodies – NASA and NOAA, simply did not communicate with each other leaving me with no choice but to run back and forth as I pieced together NASA’s knowledge of space, and NOAA’s knowledge weather. When you put the two together you have “space-weather”.

A recent study published in the science journal ‘Nature’, indicates a direct connection between the acceleration of charged particles such as galactic cosmic rays and its effect on humans and animals. Charged particles come in many forms. From the Sun, they come in the form of solar flares, CMEs (coronal mass ejections), coronal holes, filament, and gamma ray burst. The more powerful and damaging particles are the galactic cosmic rays which comes from outside our solar system. These subatomic particles, made up of around ninety percent protons move through space at close to the speed of light. Magnetic fields deflect and distort the path of the particles, making it near impossible to determine their point of origin. Collision of stars, supernovae, even dark matter have all been named as a possible source.

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As mentioned previously, during times of high solar activity (expansion), cosmic rays are better reflected from entering Earth’s atmosphere. However, during times of low solar activity (contraction), cosmic rays are far more abundant therefore have the potential to cause significant damage to our planet and all those living on it. Moreover, when you factor in the two current events happening concurrently, the scenario adds anecdotal averment of how far along this cycle we reside. First) A weakening magnetic field diminishing 10x faster than original estimates. Second) Evidence of an extended solar minimum which is going beyond one, two, three, or possibly more cycles allowing a profusion of galactic cosmic rays entering our atmosphere, with the higher energy particles penetrating deep into the Lithosphere, Mantle, and some research says right through the other side.

When scenario’s such as this occur, one must go beyond the better known short-term cycles comprised of averaging 11 yr. and 22 yr-cyl; while looking deeper into the less known medium ‘extended cycles’ such as the Milankovitch Cycle, the Laschamp Event, and the Maunder Minimum indicating that some cycles commingle while others supplant with periodicities ranging from Maunder’s 60-70 yr-cyl, to Laschamp’s 40,000 and 60,000 yr-cyl, to Milankovitch’s 23,000, 41,000, and 100,000 yr-cyl.

Then we have long-term cycles which can be traced back 550 million years.

*My eyes hurt, I have to stop here. I will pick it up tomorrow with “long-term cycles”