Gamma-Ray Burst Captured In Unprecedented Detail

Gamma-ray bursts are among the most energetic and explosive events in the universe. They are also short-lived, lasting from a few milliseconds to about a minute. This has made it tough for astronomers to observe a gamma-ray burst in detail.

Using a wide array of ground- and space-based telescope observations, an international team led by University of Maryland astronomers constructed one of the most detailed descriptions of a gamma-ray burst to date. The event, named GRB160625B, revealed key details about the initial “prompt” phase of gamma-ray bursts and the evolution of the large jets of matter and energy that form as a result of the burst. The group’s findings are published in the July 27, 2017 issue of the journal Nature.

“Gamma-ray bursts are catastrophic events, related to the explosion of massive stars 50 times the size of our sun. If you ranked all the explosions in the universe based on their power, gamma-ray bursts would be right behind the Big Bang,” said Eleonora Troja, an assistant research scientist in the UMD Department of Astronomy and lead author of the research paper. “In a matter of seconds, the process can emit as much energy as a star the size of our sun would in its entire lifetime. We are very interested to learn how this is possible.”

The group’s observations provide the first answers to some long-standing questions about how a gamma-ray burst evolves as the dying star collapses to become a black hole. First, the data suggest that the black hole produces a strong magnetic field that initially dominates the energy emission jets. Then, as the magnetic field breaks down, matter takes over and begins to dominate the jets. Most gamma-ray burst researchers thought that the jets were dominated by either matter or the magnetic field, but not both. The current results suggest that both factors play key roles.

“There has been a dichotomy in the community. We find evidence for both models, suggesting that gamma-ray burst jets have a dual, hybrid nature,” said Troja, who is also a visiting research scientist at NASA’s Goddard Space Flight Center. “The jets start off magnetic, but as the jets grow, the magnetic field degrades and loses dominance. Matter takes over and dominates the jets, although sometimes a weaker vestige of the magnetic field might survive.”

The data also suggest that synchrotron radiation — which results when electrons are accelerated in a curved or spiral pathway — powers the initial, extremely bright phase of the burst, known as the “prompt” phase. Astronomers long considered two other main candidates in addition to synchrotron radiation: black-body radiation, which results from the emission of heat from an object, and inverse Compton radiation, which results when an accelerated particle transfers energy to a photon.

“Synchrotron radiation is the only emission mechanism that can create the same degree of polarization and the same spectrum we observed early in the burst,” Troja said. “Our study provides convincing evidence that the prompt gamma-ray burst emission is driven by synchrotron radiation. This is an important achievement because, despite decades of investigation, the physical mechanism that drives gamma-ray bursts had not yet been unambiguously identified.”

Comprehensive coverage of GRB160625B from a wide variety of telescopes that gathered data in multiple spectra made these conclusions possible, the researchers said.

“Gamma-ray bursts occur at cosmological distances, with some dating back to the birth of the universe,” said Alexander Kutyrev, an associate research scientist in the UMD Department of Astronomy and a co-author of the research paper. “The events are unpredictable and once the burst occurs, it’s gone. We are very fortunate to have observations from a wide variety of sources, especially during the prompt phase, which is very difficult to capture.”

NASA’s Fermi Gamma-ray Space Telescope first detected the gamma-ray emission from GRB160625B. Soon afterward, the ground-based MASTER-IAC telescope, a part of Russia’s MASTER robotic telescope network located at the Teide Observatory in Spain’s Canary Islands, followed up with optical light observations while the prompt phase was still active.

MASTER-IAC gathered critical data on the proportion of polarized optical light relative to the total light produced by the prompt phase. Because synchrotron radiation is one of only a limited number of phenomena that can create polarized light, these data provided the crucial link between synchrotron radiation and the prompt phase of GRB160625B.

A magnetic field can also influence how much polarized light is emitted as time passes and the burst evolves. Because the researchers were able to analyze polarization data that spanned nearly the entire timeframe of the burst — a rare achievement — they were able to discern the presence of a magnetic field and track how it changed as GRB160625B progressed.

“There is very little data on polarized emission from gamma-ray bursts,” said Kutyrev, who is also an associate scientist at NASA’s Goddard Space Flight Center. “This burst was unique because we caught the polarization state at an early stage. This is hard to do because it requires a very fast reaction time and there are relatively few telescopes with this capability. This paper shows how much can be done, but to get results like this consistently, we will need new rapid-response facilities for observing gamma-ray bursts.”

Dawn Of The Cosmos: Seeing Galaxies That Appeared Soon After The Big Bang

Arizona State University astronomers Sangeeta Malhotra and James Rhoads, working with international teams in Chile and China, have discovered 23 young galaxies, seen as they were 800 million years after the Big Bang. The results from this sample have been recently published in the Astrophysical Journal.

Long ago, about 300,000 years after the beginning of the universe (the Big Bang), the universe was dark. There were no stars or galaxies, and the universe was filled with neutral hydrogen gas. In the next half billion years or so the first galaxies and stars appeared. Their energetic radiation ionized their surroundings, illuminating and transforming the universe.

This dramatic transformation, known as re-ionization, occurred sometime in the interval between 300 million years and one billion years after the Big Bang. Astronomers are trying to pinpoint this milestone more precisely and the galaxies found in this study help in this determination.

“Before re-ionization, these galaxies were very hard to see, because their light is scattered by gas between galaxies, like a car’s headlights in fog,” says Malhotra. “As enough galaxies turn on and ‘burn off the fog’ they become easier to see. By doing so, they help provide a diagnostic to see how much of the ‘fog’ remains at any time in the early universe.”

The Dark Energy Camera

To detect these galaxies, Malhotra and Rhoads have been using the Dark Energy Camera (DECam), one of the new powerful instruments in the astronomy field. DECam is installed at the National Optical Astronomy Observatory (NOAO)’s 4-meter Blanco Telescope, located at the Cerro Tololo Inter-American Observatory (CTIO), in northern Chile, at an altitude of 7,200 feet.

“Several years ago, we carried out a similar study using a 64-megapixel camera that covers the same amount of sky as the full moon,” says Rhoads. “DECam, by comparison, is a 570-megapixel camera and covers 15 times the area of the full moon in a single image.”

DECam was recently made even more powerful when it was equipped with a special narrowband filter, designed at ASU’s School of Earth and Space Exploration (SESE), primarily by Rhoads and Zheng (who was a SESE postdoctoral fellow and is currently at the Shanghai Astronomical Observatory in China), with assistance from Alistair Walker of NOAO.

“We spent several months refining the design of the filter profile, optimizing the design to get maximum sensitivity in our search” says Zheng, the lead author of this study.

Touching the Cosmic Dawn

The galaxy search using the ASU-designed filter and DECam is part of the ongoing “Lyman Alpha Galaxies in the Epoch of Reionization” project (LAGER). It is the largest uniformly selected sample that goes far enough back in the history of the universe to reach cosmic dawn.

“The combination of large survey size and sensitivity of this survey enables us to study galaxies that are common but faint, as well as those that are bright but rare, at this early stage in the universe,” says Malhotra.

Junxian Wang, a co-author on this study and the lead of the Chinese LAGER team, adds that “our findings in this survey imply that a large fraction of the first galaxies that ionized and illuminated the universe formed early, less than 800 million years after the Big Bang.”

The next steps for the team will be to build on these results. They plan to continue to search for distant star forming galaxies over a larger volume of the universe and to further investigate the nature of some of the first galaxies in the universe.

‘Strong’ 6.1-Magnitude Earthquake Strikes Off Japan Coast

An earthquake of magnitude 6.1 struck in the Pacific Ocean, off the coast of Japan, this morning.

The shaker – which is classed as “strong” – was near the island of Okinawa, which has a population of more than 1.4million.

Almost 16,000 people were killed by an earthquake off Japan’s coast in 2011.

The under-sea tremor – which has a similar depth to today’s quake – caused a tsunami, which led to the Fukushima Daiichi nuclear disaster.

The epicentre was in the Pacific Ocean – between Japan, China, South Korea and the Philippines, which has a population of 100million.

The island of Taiwan – where 24million people live – is very near.

There were no immediate reports of damage or injuries in the quake, which hit at a depth of 21 miles, about 166 miles east of Okinawa.

The US Geological Survey – which monitors earthquakes and volcanoes worldwide – said there is a “low likelihood” of casualties and damage.
There is a one in three chance up to 10 people could be killed – and only a 4% chance of more deaths.

The 1.4million people who leave nearby will have felt “weak” effects.

A USGS spokesman said: “Overall, the population in this region resides in structures that are resistant to earthquake shaking – though vulnerable structures exist.

“The predominant vulnerable building types are low-rise concrete wall and light wood frame construction.”

Japan lies on the notorious “Ring of Fire” – land around the Pacific Ocean regularly rocked by earthquakes and volcanoes.

A powerful 6.6-magnitude earthquake struck Indonesia – also in the region – back in May.

Two people were killed and more than 120 injured when an earthquake hit the Mediterranean last week.

A series of earthquakes in Wyoming has sparked fears a giant supervolcano in Yellowstone National Park could blow.

Cosmologists Produce New Maps Of Dark Matter Dynamics

New maps of dark matter dynamics in the Universe have been produced by a team of international cosmologists.

Using advanced computer modelling techniques, the research team has translated the distribution of galaxies into detailed maps of matter streams and velocities for the first time.

The research was carried out by leading cosmologists from the UK, France and Germany.

Dr Florent Leclercq from the University of Portsmouth’s Institute of Cosmology and Gravitation said: “Dark matter is a substance of yet unknown nature that scientists believe makes up more than 80 per cent of the total mass of the Universe. As it does not emit or react to light, its distribution and evolution are not directly observable and have to be inferred.”

The researchers used legacy survey data obtained during 2000 — 2008 from the Sloan Digital Sky Survey (SDSS), a major three-dimensional survey of the Universe. The survey has deep multi-colour images of one fifth of the sky and spectra for more than 900,000 galaxies. The new dark matter maps cover the Northern Sky up to a distance of 600 megaparsecs, which is the equivalent of looking back about two billion years.

The researchers used a set of phase-space analysis tools and built on research from 2015, which reconstructed the initial conditions of the nearby Universe.

Dr Leclercq said: “Adopting a phase-space approach discloses a wealth of information, which was previously only analysed in simulations and thought to be inaccessible using observations.

“Accessing this information in galaxy surveys opens up new ways of assessing the validity of theoretical models in light of observations.”

The research is published in the Journal of Cosmology and Astroparticle Physics.

Large, Distant Comets More Common Than Previously Thought

that take more than 200 years to make one revolution around the sun are notoriously difficult to study. Because they spend most of their time far from our area of the solar system, many “long-period comets” will never approach the sun in a person’s lifetime. In fact, those that travel inward from the Oort Cloud — a group of icy bodies beginning roughly 300 billion kilometers away from the sun — can have periods of thousands or even millions of years.

NASA’s Wide-field Infrared Survey Explorer (WISE) spacecraft has delivered new insights about these distant wanderers. A team of astronomers led by James Bauer, a research professor of astronomy at the University of Maryland, found that there are about seven times more long-period comets measuring at least 1 kilometer across than previously predicted.

The researchers also found that long-period comets are, on average, nearly twice as large as “Jupiter family” comets, whose orbits are shaped by Jupiter’s gravity and have periods of less than 20 years. The findings were published July 14, 2017, in The Astronomical Journal.

“The number of comets speaks to the amount of material left over from the solar system’s formation,” Bauer said. “We now know that there are more relatively large chunks of ancient material coming from the Oort Cloud than we thought.”

The Oort Cloud is too distant to be seen by current telescopes, but is thought to be a spherical distribution of small icy bodies at the outermost edge of the solar system. The density of comets within it is low, so the odds of comets colliding within it are low. Long-period comets that WISE observed probably got kicked out of the Oort Cloud millions of years ago. The observations were carried out in 2010 during the spacecraft’s primary mission, before it was renamed NEOWISE and reactivated to target near-Earth objects (NEOs) in 2013.

“Our study is a rare look at objects perturbed out of the Oort Cloud,” said Amy Mainzer, a co-author of the study based at NASA’s Jet Propulsion Laboratory in Pasadena, California and principal investigator of the NEOWISE mission. “They are the most pristine examples of what the solar system was like when it formed.”

Astronomers already had broader estimates of how many long-period and Jupiter family comets are in our solar system, but had no good way of measuring the sizes of long-period comets. This is because the cloud of gas and dust that surrounds each comet — known as a coma — appears hazy in images and obscures the comet’s nucleus.

By using WISE data that shows the infrared glow of the coma, the scientists were able to “subtract” the coma from each comet and estimate the size of the nucleus. The data came from WISE observations of 164 cometary bodies — including 95 Jupiter family comets and 56 long-period comets.

The results reinforce the idea that comets that pass by the sun more frequently tend to be smaller than those spending much more time away from the sun. That is because Jupiter family comets get more heat exposure, which causes volatile substances like water to sublimate and drag away other material from the comet’s surface as well.

“Our results mean there’s an evolutionary difference between Jupiter family and long-period comets,” Bauer said.

The existence of so many more long-period comets than predicted suggests that more of them have likely impacted planets, delivering icy materials from the outer reaches of the solar system.

Researchers also found clustered orbits among the long-period comets they studied, suggesting there could have been larger bodies that broke apart to form these groups.

The results will be important for assessing the likelihood of comets impacting our solar system’s planets, including Earth.

“Comets travel much faster than asteroids, and some of them are very big,” Mainzer said. “Studies like this will help us define what kind of hazard long-period comets may pose.”

NASA’s Jet Propulsion Laboratory in Pasadena, California, managed and operated WISE for NASA’s Science Mission Directorate in Washington, D.C. The NEOWISE project is funded by the Near-Earth Object Observation Program, now part of NASA’s Planetary Defense Coordination Office. The spacecraft was put into hibernation mode in 2011 after twice scanning the entire sky, thereby completing its main objectives. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA’s efforts to identify potentially hazardous near-Earth objects.

Venus’s Turbulent Atmosphere

Venus is often referred to as Earth’s twin because both planets share a similar size and surface composition. Also, they both have atmospheres with complex weather systems. But that is about where the similarities end: Venus is one the most hostile places in our solar system. Its atmosphere consists of 96.5 percent carbon dioxide, with surface temperatures of constantly about 500 degrees Celsius. Venus is a slowly rotating planet — it needs about 243 terrestrial days to complete one rotation. We would expect its atmosphere to rotate with the same rhythm, but in fact it takes only four days. This phenomenon is called superrotation, and it causes substantial turbulences in the planet’s atmosphere. The scientists do not yet fully understand its origin and motor, but are working on an answer to this puzzle. The many waves in the planet’s atmosphere may play an important role.

The research results were generated by an international collaboration headed by the Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA). Experts in space and astronautical science and astrophysics from universities and institutions in Japan, Spain, Italy, and Germany are cooperating in the project. From Germany, the Rhenish Institute for Environmental Research at the University of Cologne and the Center for Astronomy and Astrophysics at Technische Universität Berlin are involved.

The research team analysed data generated by the spacecraft Venus Express to investigate components of Venus’s complex atmosphere, including thermal measurements with regard to horizontal and vertical wave patterns. The data also included first global measurements from the tracking of individual features in thermal emission images at 3.8 and 5.0 ?m (micrometer) during 2006-2008 and 2015.

Vertical information in unison with horizontal data help to understand the nature of the ob-served wave patterns. The vertical information from the VeRa instrument (an atmosphere experiment where radio waves sent by spacecraft Venus Express are being analysed) could help to identify the observed waves as gravity waves. This, in turn, is crucial for the analysis of atmospheric processes.

Dr. Silvia Tellmann is Vice-Director of the Department of Planetary Research at the Rhenish Institute for Environmental Research at the University of Cologne. She is an expert on the structure, dynamics, and circulation of planetary atmospheres and a co-author of the study. ‘We were able to relate the stationary gravity waves found at higher altitudes with the surface elevations of Venus’, she says. ‘Hence, the waves can be explained with wind currents caused by topographical obstacles. We assume that these stationary waves are substantial for the continuity of the superrotation in the atmosphere of Venus.’

BREAKING NEWS: August 21st Full Solar Eclipse Geographical Areas of Concern

I have highlighted areas of concern as related to the causal effects of a total solar eclipse. If tectonics are at their tipping point, it would not take much to set them off. As mentioned, it is mostly the rapid temperature change which causes an expansion and contraction of Earth’s lithosphere, even if ever so slight.

Most ‘mantle plumes’ as well as volcanoes are sub-marine (ocean bottom); hence the rapid shift in ocean temperatures is also prone to set off a rippling effect which is often unpredictable due to the spider webbing tentacles which connect a system of mantle plumes and volcanoes.

A mantle plume is a large column of hot rock (magma) mostly originating from Earth’s core-mantle boundary. This flow of viscous material rises through the mantle, asthenosphere, and lithosphere finding its way to Earth’s surface or crust. The expanding or contracting movement of these events are the cause of earthquakes and volcanoes. The surface includes ocean bottoms causing an increase of ocean temperatures, which in-turn destabilizing the atmosphere contributing to forming or escalation of tropical storms or hurricanes.

Next article will address perhaps a less scientific direction which suggest the current mode of global political dysfunction, may have some roots in history showing a pattern of “what happens below, reflects what happens above”. This suggest the turmoil which results from earth changing events appears to be in-sync with emotional unrest. Continued scientific data will of course follow.

Watch for ongoing reports as information comes in. I also plan to present greater outlines to the science behind by research, especially for those who may be new to my work.