Tag: Govinda Dhungana

Solving the dark energy mystery: A new sky survey assignment for a 45-year-old telescope

Post author By Margaret Allen
Post date February 16, 2018

SMU and other members of a scientific consortium prepare for installation of the Dark Energy Spectroscopic Instrument to survey the night sky from a mile-high mountain peak in Arizona

As part of a large scientific consortium studying dark energy, SMU physicists are on course to help create the largest 3-D map of the universe ever made.

The map will emerge from data gathered by the Dark Energy Spectroscopic Instrument (DESI) being installed on the Nicholas U. Mayall Telescope atop a mountain in Arizona.

The map could help solve the mystery of dark energy, which is driving the accelerating expansion of the universe.

DESI will capture about 10 times more data than a predecessor survey of space using an array of 5,000 swiveling robots. Each robot will be carefully choreographed to point a fiber-optic cable at a preprogrammed sequence of deep-space objects, including millions of galaxies and quasars, which are galaxies that harbor massive, actively feeding black holes.

“DESI will provide the first precise measures of the expansion history of the universe covering approximately the last 10 billion years,” said SMU physicist Robert Kehoe, a professor in the SMU Department of Physics. “This is most of the 13 billion year age of the universe, and it encompasses a critical period in which the universe went from being matter-dominated to dark-energy dominated.”

The universe was expanding, but at a slowing pace, until a few billion years ago, Kehoe said.

“Then the expansion started accelerating,” he said. “The unknown ‘dark energy’ driving that acceleration is now dominating the universe. Seeing this transition clearly will provide a critical test of ideas of what this dark energy is, and how it may tie into theories of gravitation and other fundamental forces.”

The Mayall telescope was originally commissioned 45 years ago to survey the night sky and record observations on glass photographic plates. The telescope is tucked inside a 14-story, 500-ton dome atop a mile-high peak at the National Science Foundation’s Kitt Peak National Observatory – part of the National Optical Astronomy Observatory.

SMU researchers have conducted observing with the Mayall. Decommissioning of that telescope allows for building DESI in it’s place, as well as reusing some parts of the telescope and adding major new sytems. As part of DESI, SMU is involved in development of software for operation of the experiment, as well as for data simulation to aid data anlysis.

“We are also involved in studying the ways in which observational effects impact the cosmology measurements DESI is pursuing,” Kehoe said. SMU graduate students Govinda Dhungana and Ryan Staten also work on DESI. A new addition to the SMU DESI team, post-doctoral researcher Sarah Eftekharzadeh, is working on the SMU software and has studied the same kinds of galaxies
DESI will be measuring.

Now the dome is closing on the previous science chapters of the 4-meter Mayall Telescope so that it can prepare for its new role in creating the 3-D map.

The temporary closure sets in motion the largest overhaul in the telescope’s history and sets the stage for the installation of the Dark Energy Spectroscopic Instrument, which will begin a five-year observing run next year.

“This day marks an enormous milestone for us,” said DESI Director Michael Levi of the Department of Energy’s Lawrence Berkeley National Laboratory , which leads the project’s international collaboration. “Now we remove the old equipment and start the yearlong process of putting the new stuff on.”

More than 465 researchers from about 71 institutions are participating in the DESI collaboration.

The entire top end of the telescope, which weighs as much as a school bus and houses the telescope’s secondary mirror and a large digital camera, will be removed and replaced with DESI instruments. A large crane will lift the telescope’s top end through the observing slit in its dome.

Besides providing new insights about the universe’s expansion and large-scale structure, DESI will also help to set limits on theories related to gravity and the formative stages of the universe, and could even provide new mass measurements for a variety of elusive yet abundant subatomic particles called neutrinos.

“One of the primary ways that we learn about the unseen universe is by its subtle effects on the clustering of galaxies,” said DESI collaboration co-spokesperson Daniel Eisenstein of Harvard University. “The new maps from DESI will provide an exquisite new level of sensitivity in our study of cosmology.”

Mayall’s sturdy construction is perfect platform for new 9-ton instrument
The Mayall Telescope has played an important role in many astronomical discoveries, including measurements supporting the discovery of dark energy and establishing the role of dark matter in the universe from measurements of galaxy rotation. Its observations have also been used in determining the scale and structure of the universe. Dark matter and dark energy together are believed to make up about 95 percent of all of the universe’s mass and energy.

It was one of the world’s largest optical telescopes at the time it was built, and because of its sturdy construction it is perfectly suited to carry the new 9-ton instrument.

“We started this project by surveying large telescopes to find one that had a suitable mirror and wouldn’t collapse under the weight of such a massive instrument,” said Berkeley Lab’s David Schlegel, a DESI project scientist.

Arjun Dey, the NOAO project scientist for DESI, explained, “The Mayall was precociously engineered like a battleship and designed with a wide field of view.”

The expansion of the telescope’s field-of-view will allow DESI to map out about one-third of the sky.

DESI will transform the speed of science with automated preprogrammed robots
Brenna Flaugher, a DESI project scientist who leads the astrophysics department at Fermi National Accelerator Laboratory, said DESI will transform the speed of science at the Mayall Telescope.

“The telescope was designed to carry a person at the top who aimed and steered it, but with DESI it’s all automated,” she said. “Instead of one at a time we can measure the velocities of 5,000 galaxies at a time – we will measure more than 30 million of them in our five-year survey.”

DESI will use an array of 5,000 swiveling robots, each carefully choreographed to point a fiber-optic cable at a preprogrammed sequence of deep-space objects, including millions of galaxies and quasars, which are galaxies that harbor massive, actively feeding black holes.

The fiber-optic cables will carry the light from these objects to 10 spectrographs, which are tools that will measure the properties of this light and help to pinpoint the objects’ distance and the rate at which they are moving away from us. DESI’s observations will provide a deep look into the early universe, up to about 11 billion years ago.

DESI will capture about 10 times more data than a predecessor survey
The cylindrical, fiber-toting robots, which will be embedded in a rounded metal unit called a focal plate, will reposition to capture a new exposure of the sky roughly every 20 minutes. The focal plane assembly, which is now being assembled at Berkeley Lab, is expected to be completed and delivered to Kitt Peak this year.

DESI will scan one-third of the sky and will capture about 10 times more data than a predecessor survey, the Baryon Oscillation Spectroscopic Survey (BOSS). That project relied on a manually rotated sequence of metal plates – with fibers plugged by hand into pre-drilled holes – to target objects.

All of DESI’s six lenses, each about a meter in diameter, are complete. They will be carefully stacked and aligned in a steel support structure and will ultimately ride with the focal plane atop the telescope.

Each of these lenses took shape from large blocks of glass. They have criss-crossed the globe to receive various treatments, including grinding, polishing, and coatings. It took about 3.5 years to produce each of the lenses, which now reside at University College London in the U.K. and will be shipped to the DESI site this spring.

Precise measurements of millions of galaxies will reveal effects of dark energy
The Mayall Telescope has most recently been enlisted in a DESI-supporting sky survey known as the Mayall z-Band Legacy Survey, which is one of four sky surveys that DESI will use to preselect its targeted sky objects. SMU astrophysicists carried out observing duties on that survey, which wrapped up just days ago on Feb. 11, to support the coming DESI scientific results.

Data from these surveys are analyzed at Berkeley Lab’s National Energy Research Scientific Computing Center, a DOE Office of Science User Facility. Data from these surveys have been released to the public at http://legacysurvey.org.

“We can see about a billion galaxies in the survey images, which is quite a bit of fun to explore,” Schlegel said. “The DESI instrument will precisely measure millions of those galaxies to see the effects of dark energy.” 

Levi noted that there is already a lot of computing work underway at the Berkeley computing center to prepare for the stream of data that will pour out of DESI once it starts up.

“This project is all about generating huge quantities of data,” Levi said. “The data will go directly from the telescope to the Berkeley computing center for processing. We will create hundreds of universes in these computers and see which universe best fits our data.”

Installation of DESI’s components is expected to begin soon and to wrap up in April 2019, with first science observations planned in September 2019.

“Installing DESI on the Mayall will put the telescope at the heart of the next decade of discoveries in cosmology,” said Risa Wechsler, DESI collaboration co-spokesperson and associate professor of physics and astrophysics at SLAC National Accelerator Laboratory and Stanford University. “The amazing 3-D map it will measure may solve some of the biggest outstanding questions in cosmology, or surprise us and bring up new ones.” — Berkeley Lab and SMU

Tags Dark Energy Spectroscopic Instrument, Dedman College, DESI, Govinda Dhungana, Robert Kehoe, Ryan Staten, Sarah Eftekharzadeh, SMU Department of Physics

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Nearby massive star explosion 30 million years ago equaled brightness of 100 million suns

Post author By Margaret Allen
Post date April 26, 2016

Analysis of exploding star’s light curve and color spectrum reveal spectacular demise of one of the closest supernova to Earth in recent years; its parent star was so big it’s radius was 200 times larger than our sun

A giant star that exploded 30 million years ago in a galaxy near Earth had a radius prior to going supernova that was 200 times larger than our sun, according to astrophysicists at Southern Methodist University, Dallas.

The sudden blast hurled material outward from the star at a speed of 10,000 kilometers a second. That’s equivalent to 36 million kilometers an hour or 22.4 million miles an hour, said SMU physicist Govinda Dhungana, lead author on the new analysis.

The comprehensive analysis of the exploding star’s light curve and color spectrum have revealed new information about the existence and sudden death of supernovae in general, many aspects of which have long baffled scientists.

“There are so many characteristics we can derive from the early data,” Dhungana said. “This was a big massive star, burning tremendous fuel. When it finally reached a point its core couldn’t support the gravitational pull inward, suddenly it collapsed and then exploded.”

The massive explosion was one of the closest to Earth in recent years, visible as a point of light in the night sky starting July 24, 2013, said Robert Kehoe, SMU physics professor, who leads SMU’s astrophysics team.

The explosion, termed by astronomers Supernova 2013ej, in a galaxy near our Milky Way was equal in energy output to the simultaneous brightness of 100 million of the Earth’s suns.

The star was one of billions in the spiral galaxy M74 in the constellation Pisces.

Considered close by supernova standards, SN 2013ej was in fact so far away that light from the explosion took 30 million years to reach Earth. At that distance, even such a large explosion was only visible by telescopes.

Dhungana and colleagues were able to explore SN 2013ej via a rare collection of extensive data from seven ground-based telescopes and NASA’s Swift satellite.

The data span a time period prior to appearance of the supernova in July 2013 until more than 450 days after.

The team measured the supernova’s evolving temperature, its mass, its radius, the abundance of a variety of chemical elements in its explosion and debris and its distance from Earth. They also estimated the time of the shock breakout, the bright flash from the shockwave of the explosion.

The star’s original mass was about 15 times that of our sun, Dhungana said. Its temperature was a hot 12,000 Kelvin (approximately 22,000 degrees Fahrenheit) on the tenth day after the explosion, steadily cooling until it reached 4,500 Kelvin after 50 days. The sun’s surface is 5,800 Kelvin, while the Earth’s core is estimated to be about 6,000 Kelvin.

The new measurements are published online here in the May 2016 issue of The Astrophysical Journal, “Extensive spectroscopy and photometry of the Type IIP Supernova 2013j.”

Shedding new light on supernovae, mysterious objects of our universe
Supernovae occur throughout the universe, but they are not fully understood. Scientists don’t directly observe the explosions but instead detect changes in emerging light as material is hurled from the exploding star in the seconds and days after the blast.

Telescopes such as SMU’s robotic ROTSE-IIIb telescope at McDonald Observatory in Texas, watch our sky and pick up the light as a point of brightening light. Others, such as the Hobby Eberly telescope, also at McDonald, observe a spectrum.

SN 2013ej is M74’s third supernova in just 10 years. That is quite frequent compared to our Milky Way, which has had a scant one supernova observed over the past 400 years. NASA estimates that the M74 galaxy consists of 100 billion stars.

M74 is one of only a few dozen galaxies first cataloged by the astronomer Charles Messier in the late 1700s. It has a spiral structure — also the Milky Way’s apparent shape — indicating it is still undergoing star formation, as opposed to being an elliptical galaxy in which new stars no longer form.

It’s possible that planets were orbiting SN 2013ej’s progenitor star prior to it going supernova, in which case those objects would have been obliterated by the blast, Kehoe said.

“If you were nearby, you wouldn’t know there was a problem beforehand, because at the surface you can’t see the core heating up and collapsing,” Kehoe said. “Then suddenly it explodes — and you’re toast.”

Distances to nearby galaxies help determine cosmic distance ladder
Scientists remain unsure whether supernovae leave behind a black hole or a neutron star like a giant atomic nucleus the size of a city.

“The core collapse and how it produces the explosion is particularly tricky,” Kehoe said. “Part of what makes SN 2013ej so interesting is that astronomers are able to compare a variety of models to better understand what is happening. Using some of this information, we are also able to calculate the distance to this object. This allows us a new type of object with which to study the larger universe, and maybe someday dark energy.”

Being 30 million light years away, SN 2013ej was a relatively nearby extragalactic event, according to Jozsef Vinko, astrophysicist at Konkoly Observatory and University of Szeged in Hungary.

“Distances to nearby galaxies play a significant role in establishing the so-called cosmic distance ladder, where each rung is a galaxy at a known distance.”

Vinko provided important data from telescopes at Konkoly Observatory and Hungary’s Baja Observatory and carried out distance measurement analysis on SN 2013ej.

“Nearby supernovae are especially important,” Vinko said. “Paradoxically, we know the distances to the nearest galaxies less certainly than to the more distant ones. In this particular case we were able to combine the extensive datasets of SN 2013ej with those of another supernova, SN 2002ap, both of which occurred in M74, to suppress the uncertainty of their common distance derived from those data.”

Supernova spectrum analysis is like taking a core sample
While stars appear to be static objects that exist indefinitely, in reality they are primarily a burning ball, fueled by the fusion of elements, including hydrogen and helium into heavier elements. As they exhaust lighter elements, they must contract in the core and heat up to burn heavier elements. Over time, they fuse the various chemical elements of the periodic table, proceeding from lightest to heaviest. Initially they fuse helium into carbon, nitrogen and oxygen. Those elements then fuel the fusion of progressively heavier elements such as sulfur, argon, chlorine and potassium.

“Studying the spectrum of a supernova over time is like taking a core sample,” Kehoe said. “The calcium in our bones, for example, was cooked in a star. A star’s nuclear fusion is always forging heavier and heavier elements. At the beginning of the universe there was only hydrogen and helium. The other elements were made in stars and in supernovae. The last product to get created is iron, which is an element that is so heavy it can’t be burned as fuel.”

Dhungana’s spectrum analysis of SN 2013ej revealed many elements, including hydrogen, helium, calcium, titanium, barium, sodium and iron.

“When we have as many spectra as we have for this supernova at different times,” Kehoe added, “we are able to look deeper and deeper into the original star, sort of like an X-ray or a CAT scan.”

SN 2013ej’s short-lived existence was just tens of millions of years
Analysis of SN 2013ej’s spectrum from ultraviolet through infrared indicates light from the explosion reached Earth July 23, 2013. It was discovered July 25, 2013 by the Katzman Automatic Imaging Telescope at California’s Lick Observatory. A look back at images captured by SMU’s ROTSE-IIIb showed that SMU’s robotic telescope detected the supernova several hours earlier, Dhungana said.

“These observations were able to show a rapidly brightening supernova that started just 20 hours beforehand,” he said. “The start of the supernova, termed ‘shock breakout,’ corresponds to the moment when the internal explosion crashes through the star’s outer layers.”

Like many others, SN 2013ej was a Type II supernova. That is a massive star still undergoing nuclear fusion. Once iron is fused, the fuel runs out, causing the core to collapse. Within a quarter second the star explodes.

Supernovae have death and birth written all over them
Massive stars typically have a shorter life span than smaller ones.

“SN 2013ej probably lived tens of millions of years,” Kehoe said. “In universe time, that’s the blink of an eye. It’s not very long-lived at all compared to our sun, which will live billions of years. Even though these stars are bigger and have a lot more fuel, they burn it really fast, so they just get hotter and hotter until they just gobble up the matter and burn it.”

For most of its brief life, SN 2013ej would probably have burned hydrogen, which then fused to helium, burning for a few hundred thousand years, then perhaps carbon and oxygen for a few hundred days, calcium for a few months and silicon for several days.

“Supernovae have death and birth written all over them,” Kehoe said. “Not only do they create the elements we are made of, but the shockwave that goes out from the explosion — that’s where our solar system comes from.”

Outflowing material slams into clouds of material in interstellar space, causing it to collapse and form a solar system.

“The heavy elements made in the supernova and its parent star are those which comprise the bulk of terrestrial planets, like Earth, and are necessary for life,” Kehoe said.

Besides physicists in the SMU Department of Physics, researchers on the project also included scientists from the University of Szeged, Szeged, Hungary; the University of Texas, Austin, Texas; Konkoly Observatory, Budapest, Hungary; and the University of California, Berkeley, Calif. — Margaret Allen

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

Tags Dedman College, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

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Houston Chronicle: Texas scientists spot 12-billion-year old star explosion

Post author By Margaret Allen
Post date June 8, 2014

“You’re looking at things a long time ago in the universe, you can get a sense for the movie of the universe,” said Kehoe. “It’s the evolution of the universe.”

The Texas newspaper the Houston Chronicle covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

The astronomy team in May reported observation of intense light from the enormous explosion of a star more than 12 billion years ago — shortly after the Big Bang — that recently reached Earth and was visible in the sky.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.

Recorded as GRB 140419A by NASA’s Gamma-ray Coordinates Network, the burst was spotted at 11 p.m. April 19 by SMU’s robotic telescope at the McDonald Observatory in the Davis Mountains of West Texas.

Houston Chronicle reporter Heather Alexander reported the news in his article “Texas scientists spot 12-billion-year old star explosion.”

Read the full story.

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By Heather Alexander
Houston Chronicle

Texas scientists have spotted a massive explosion in space that dates back 12 billion years, almost to the time of the Big Bang, according to Southern Methodist University in Dallas.

NASA satellites recorded the burst and signalled back to the McDonald Observatory in West Texas. Telescope pictures showed a gamma ray burst, believed to be the collapse of a star.

“Gamma-ray bursts are the most powerful explosions in the universe since the Big Bang,” said graduate student Farley Ferrante, who was monitoring the telescope. “These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.”

The scientists said explosions like this are key to understanding the development of the universe.

“Twelve billion years ago, it was a very different universe,” said Robert Kehoe, physics professor and leader of the SMU astronomy team. “It was just hydrogen and helium. There were no rocks, there was no matter; our solar system had not formed.”

Kehoe says explosions like the one shown in the photo are stars exploding, scattering new elements like carbon, oxygen, silicon and iron into the surrounding area.

Read the full story.

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SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.

Tags Dedman College, Farley Ferrante, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

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Digital Journal: Scientists spot 12-billion-year-old star burst

Post author By Margaret Allen
Post date June 8, 2014

A star exploded billions of years back, but the light of this explosion has just reached the earth, allowing scientists to peep into the past of the universe

The news web site digitaljournal.com covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.

Digitaljournal.com reporter Sonia D’Costa reported the news in her article “Scientists spot 12-billion-year-old star burst.”

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By Sonia D’Costa
digitaljournal.com

A star exploded billions of years back, but the light of this explosion has just reached the earth, allowing scientists to peep into the past of the universe and figure out what it might have been like during the earliest stages of its development.

The light was observed through a telescope at the McDonald Observatory at Fort Davis in Texas. Called a gamma-ray burst, this stellar explosion is believed to have taken place just after the Big Bang, over 12 billion years in the past.

Farley Ferrante, a physics student at the Southern Methodist University (SMU), which owns the telescope, said: “Gamma-ray bursts are the most powerful explosions in the universe since the Big Bang. These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.”

Read the full story.

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Tags Dedman College, Farley Ferrante, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

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Global Post: Light from this 12-billion-year-old explosion just reached Earth

Post author By Margaret Allen
Post date June 7, 2014

To put the age of the latest discovery into context, scientists believe the Big Bang occurred 13.81 billion years ago.

The news service Global Post covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.

Global Post reporter Sarah Wolfe reported the news in his article “Light from this 12-billion-year-old explosion just reached Earth.”

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By Sarah Wolfe
Global Post

It took 12 billion years, but light from a massive explosion that occurred shortly after the Big Bang has just reached Earth.

The rare gamma-ray burst could help scientists understand more about the early universe.

Recorded as GRB 140423A, the explosion was first observed in April by the telescope Rotse-IIIB at an observatory in western Texas owned by Southern Methodist University.

The area of the explosion’s peak afterglow, circled in blue and yellow, can be seen in the image above. A bright star sits to its left.

Gamma-ray bursts are believed to be the catastrophic collapse of a star at the end of its life.

“As NASA points out, gamma-ray bursts are the most powerful explosions in the universe since the Big Bang,” Farley Ferrante, a graduate student at Southern Methodist University who monitored the explosions with astronomers in Hawaii and Turkey, said in a release from the university.

“These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.”

Scientists weren’t even able to detect visual light from gamma-ray bursts until technology improved in the late 1990s. Gamma rays have the shortest wavelengths and can only be seen using special detectors.

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Tags Dedman College, Farley Ferrante, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

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CBS News: See an exploding star from 12 billion years ago

Post author By Margaret Allen
Post date June 7, 2014

Armed with images of the burst, astronomers can now analyze the data in order to understand more about the structure of the universe at its infancy

CBS News covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.

CBS News reporter Hani Shawwa reported the news in his article “See an exploding star from 12 billion years ago.”

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By Hani Shawwa
CBS News

It took billions of years for the light of this cosmic explosion to reach Earth, and now it’s offering scientists a rare glimpse of the universe at one of its earliest stages.

A McDonald Observatory telescope in Fort Davis, Texas captured the image of a gamma-ray burst — the enormous explosion of a star, which took place more than 12 billion years ago, shortly after the Big Bang.

“Gamma-ray bursts are the most powerful explosions in the universe since the Big Bang. These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years,” said Farley Ferrante, a graduate student at Southern Methodist University’s Department of Physics, who monitored the explosion along with two astronomers in Turkey and Hawaii.

The phenomenon is not well understood by astronomers, but it is believed to be the result of a catastrophic collapse of a star at the end of its life.

“Gamma-ray bursts may be particularly massive cousins to supernovae… By studying them, we learn about supernovae,” said Robert Kehoe, physics professor and leader of the SMU astronomy team.

The photo was snapped in mid-April and released this week.

Scientists weren’t able to detect optical light from gamma-ray bursts until the late 1990s, when telescope technology improved.

Among all lights in the electromagnetic spectrum, gamma rays have the shortest wavelengths and are visible only using special detectors.

Read the full story.

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Tags Dedman College, Farley Ferrante, Govinda Dhungana, Robert Kehoe, SMU Department of Physics

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Daily Mail: Huge 12 billion-year-old explosion in space has been spotted from Earth – and it could reveal secrets of the early universe

Post author By Margaret Allen
Post date June 6, 2014

Armed with images of the burst, astronomers can now analyze the data in order to understand more about the structure of the universe at its infancy

The U.K.’s widely read newspaper the Daily Mail covered the astronomy research of physicist Robert Kehoe, SMU professor, and two graduate students in the SMU Department of Physics, Farley Ferrante and Govinda Dhungana.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by SMU.
Gamma-ray bursts are believed to be the catastrophic collapse of a star at the end of its life. SMU physicists report that their telescope was the first on the ground to observe the burst and to capture an image.

Daily Mail reporter Jonathan O’Callaghan reported the news in his article “Huge 12 billion-year-old explosion in space has been spotted from Earth – and it could reveal secrets of the early universe.”

Read the full story.

EXCERPT:

By Jonathan O’Callaghan
Daily Mail

One of the biggest and hottest explosions in the universe – a rare event known as a gamma-ray burst (GRB) – has been spotted on camera.

And this particular event, caused by the enormous explosions of a star, occurred shortly after the Big Bang about 12.1 billion years ago.

The intense light recently reached Earth and it could give astronomers useful information about the conditions in the young universe.

Gamma-ray bursts are believed to be the catastrophic collapse of a star at the end of its life.

The observation was made by the telescope Rotse-IIIB at the McDonald Observatory in the Davis Mountains of West Texas, owned by the Southern Methodist University (SMU) in Dallas.

SMU physicists report that their telescope was the first on the ground to observe the burst, and to capture an image.

This particular explosion, first spotted back in April, was recorded as GRB 140419A by Nasa’s Gamma-ray Coordinates Network (GCN).

Gamma-ray bursts are not well understood by astronomers, but they are considered important, according to Farley Ferrante, a graduate student in SMU’s Department of Physics, who monitored the observations along with two astronomers in Turkey and Hawaii.

‘As Nasa points out, gamma-ray bursts are the most powerful explosions in the universe since the Big Bang,’ he said.

‘These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.’

Some of these GRBs appear to be related to supernovae and correspond to the end-of-life of a massive star, said Dr Robert Kehoe, physics professor and leader of the SMU astronomy team.

‘Gamma-ray bursts may be particularly massive cousins to supernovae, or may correspond to cases in which the explosion ejecta are more beamed in our direction. By studying them, we learn about supernovae,’ Kehoe said.

Read the full story.

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Observed by Texas telescope: Light from huge explosion 12 billion years ago reaches Earth

Post author By Margaret Allen
Post date June 3, 2014

Known as a gamma-ray burst, the intense light captured in the night sky resulted from one of the biggest and hottest explosions in the universe, occurring shortly after the Big Bang.

Intense light from the enormous explosion of a star more than 12 billion years ago — shortly after the Big Bang — recently reached Earth and was visible in the sky.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope, ROTSE-IIIb, owned by Southern Methodist University, Dallas.

Gamma-ray bursts are believed to be the catastrophic collapse of a star at the end of its life. SMU physicists report that their telescope was the first on the ground to observe the burst and to capture an image, said Farley Ferrante, a graduate student in SMU’s Department of Physics, who monitored the observations along with two astronomers in Turkey and Hawaii.

Gamma-ray burst 1404191 was spotted at 11 p.m. on April 19 by SMU's robotic ROTSE-IIIb telescope at McDonald Observatory, Fort Davis, Texas. — Gamma-ray burst 1404191 was spotted at 11 p.m. April 19 by SMU’s robotic ROTSE-IIIb telescope at McDonald Observatory, Fort Davis, Texas.

Gamma-ray bursts are not well understood by astronomers, but they are considered important, Ferrante said.

“As NASA points out, gamma-ray bursts are the most powerful explosions in the universe since the Big Bang,” he said. “These bursts release more energy in 10 seconds than our Earth’s sun during its entire expected lifespan of 10 billion years.”

Some of these gamma-ray bursts appear to be related to supernovae, and correspond to the end-of-life of a massive star, said Robert Kehoe, physics professor and leader of the SMU astronomy team.

“Gamma-ray bursts may be particularly massive cousins to supernovae, or may correspond to cases in which the explosion ejecta are more beamed in our direction. By studying them, we learn about supernovae,” Kehoe said.

Scientists weren’t able to detect optical light from gamma-ray bursts until the late 1990s, when telescope technology improved. Among all lights in the electromagnetic spectrum, gamma rays have the shortest wavelengths and are visible only using special detectors.

Gamma-ray bursts result from hot stars that measure as enormous as 50 solar masses. The explosion occurs when the stars run out of fuel and collapse in on themselves, forming black holes.

The ROTSE-IIIb robotic telescope at McDonald Observatory, Fort Davis, Texas. (Photo: McDonald Observatory)

Outer layers detonate, shooting out material along the rotation axis in powerful, high-energy jets that include gamma radiation.

As the gamma radiation declines, the explosion produces an afterglow of visible optical light. The light, in turn, fades very quickly, said Kehoe. Physicists calculate the distance of the explosion based on the shifting wavelength of the light, or redshift.

“The optical light is visible for anywhere from a few seconds to a few hours,” Kehoe said. “Sometimes optical telescopes can capture the spectra. This allows us to calculate the redshift of the light, which tells us how fast the light is moving away from us. This is an indirect indication of the distance from us.”

Observational data from gamma-ray bursts allows scientists to understand structure of the early universe
To put into context the age of the new gamma-ray burst discoveries, Kehoe and Ferrante point out that the Big Bang occurred 13.81 billion years ago. GRB 140419A is at a red shift of 3.96, Ferrante said.

“That means that GRB 140419A exploded about 12.1 billion years ago,” he said, “which is only about one-and-a-half billion years after the universe began. That is really old.”

Armed with images of the burst, astronomers can analyze the observational data to draw further conclusions about the structure of the early universe.

“At the time of this gamma-ray burst’s explosion, the universe looked vastly different than it does now,” Kehoe said. “It was an early stage of galaxy formation. There weren’t heavy elements to make Earth-like planets. So this is a glimpse at the early universe. Observing gamma-ray bursts is important for gaining information about the early universe.”

GRB 140419A’s brightness, measured by its ability to be seen by someone on Earth, was of the 12th magnitude, Kehoe said, indicating it was only 10 times dimmer than what is visible through binoculars, and only 200 times dimmer than the human eye can see, Kehoe said.

“The difference in brightness is about the same as between the brightest star you can see in the sky, and the dimmest you can see with the naked eye on a clear, dark night,” Kehoe said. “Considering this thing was at the edge of the visible universe, that’s an extreme explosion. That was something big. Really big.”

SMU telescope responded to NASA satellite’s detection and notification
SMU’s Robotic Optical Transient Search Experiment (ROTSE) IIIb is a robotic telescope. It is part of a network of ground telescopes responsive to a NASA satellite that is central to the space agency’s Swift Gamma-Ray Burst Mission. Images of the gamma-ray bursts are at http://bit.ly/1kKZeh5.

When the Swift satellite detects a gamma-ray burst, it instantly relays the location. Telescopes around the world, such as SMU’s ROTSE-IIIb, swing into action to observe the burst’s afterglow and capture images, said Govinda Dhungana, an SMU graduate student who participated in the gamma-ray burst research.

SMU’s ROTSE-IIIb observes optical emission from several gamma-ray bursts each year. It observed GRB 140419A just 55 seconds after the burst was detected by Swift.

Just days later, ROTSE-IIIb observed and reported a second rare and distant gamma-ray burst, GRB 140423A, at 3:30 a.m. April 23. The redshift of that burst corresponds to a look back in time of 11.8 billion years. ROTSE-IIIb observed it 51 seconds after the burst was detected by Swift.

“We have the brightest detection and the earliest response on both of those because our telescope is fully robotic and no human hands were involved,” Ferrante said.

Ferrante, the first to check observations on GRB 140423A, is first-author on that gamma-ray burst. Tolga Guver, associate professor in the Department of Astronomy and Space Sciences at Istanbul University, Turkey, is second author. On GRB 140419A, Guver is first author and Ferrante is second.

The research is funded by the Texas Space Grant Consortium, an affiliate of NASA. — Margaret Allen

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UPI: Cosmic explosions give dark energy clues

Post author By Margaret Allen
Post date March 4, 2013

The international news wire service United Press International has covered the SMU Physics Department’s recent supernovae discoveries. The article, “Cosmic explosions give dark energy clues,” was published Feb. 27. Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova by SMU graduate students in the physics department.

Both supernovae were spotted with the Robotic Optical Transient Search Experiment‘s robotic telescope ROTSE3b, which is now operated by SMU graduate students. ROTSE3b is at the McDonald Observatory in the Davis Mountains of West Texas near Fort Davis.

The Central Bureau for Astronomical Telegrams of the International Astronomical Union officially designated the discoveries as Supernova 2013X and Supernova 2012ha.

Ferrante and Dhungana made both discoveries as part of an international collaboration of physicists from nine universities. Everest and Sherpa were discovered with a fully automated, remotely controlled robotic telescope at the University of Texas’ McDonald Observatory. The discovery is a first for the SMU collaboration members.

See the article.

EXCERPT:

DALLAS, Feb. 27 (UPI) — Light from exploding stars is improving the astronomical “yardstick” used to calculate the acceleration of the expansion of the universe, U.S. scientists say.

The light from two supernovae, massive stars that exploded hundreds of millions of years ago, has recently reached Earth, Southern Methodist University researchers said.

A supernova discovered Feb. 6 exploded about 450 million years ago, while a second supernova discovered Nov. 20 exploded about 230 million years ago, Farley Ferrante, an SMU graduate student who made the initial Feb. 6 observation, said.

Both are Type 1a supernovae, the result of white dwarf explosions, he said.

“We call these Type 1a supernovae standard candles,” Ferrante said. “Since Type 1a supernovae begin from this standard process, their intrinsic brightness is very similar. So they become a device by which scientists can measure cosmic distance.”

Type 1a supernova provide astronomers with indirect information about dark energy, which makes up 73 percent of the mass-energy in the universe and is theorized as being responsible for the accelerating expansion of our universe at various times after the Big Bang.

“Every exploding star observed allows astronomers to more precisely calibrate the increasing speed at which our universe is expanding,” Ferrante said. “The older the explosion, the farther away, the closer it was to the Big Bang and the better it helps us understand dark energy.”

See the article.

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SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.

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ANI News: Exploding stars offer clues to dark energy

Post author By Margaret Allen
Post date March 4, 2013

The Asian news wire service Asian News International has covered the SMU Physics Department’s recent supernovae discoveries. The article, “Exploding stars offer clues to dark energy,” was published Feb. 28. Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova by SMU graduate students in the physics department.

The Central Bureau for Astronomical Telegrams of the International Astronomical Union officially designated the discoveries as Supernova 2013X and Supernova 2012ha.

Read the full article.

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Washington, February 28 (ANI): Observation of two bright exploding stars is improving the astronomical “tape measure” used to calculate the acceleration of the expansion of the universe, say scientists.

Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova, Southern Methodist University scientists said.

A supernova discovered Feb. 6 exploded about 450 million years ago, said Farley Ferrante, a graduate student at Southern Methodist University, Dallas, who made the initial observation.

The exploding star is in a relatively empty portion of the sky labeled “anonymous” in the faint constellation Canes Venatici. Home to a handful of galaxies, Canes Venatici is near the constellation Ursa Major , best known for the Big Dipper.

A second supernova discovered Nov. 20 exploded about 230 million years ago, said Ferrante, who made the initial observation. That exploding star is in one of the many galaxies of the Virgo constellation.

Both supernovae were spotted with the Robotic Optical Transient Search Experiment’s robotic telescope ROTSE3b, which is now operated by SMU graduate students. ROTSE3b is at the McDonald Observatory in the Davis Mountains of West Texas near Fort Davis.

The supernova that exploded about 450 million years ago is officially designated Supernova 2013X. It occurred when life on Earth consisted of creatures in the seas and oceans and along coastlines. Following naming conventions for supernova, Supernova 2013X was nicknamed “Everest” by Govinda Dhungana, an SMU graduate student who participated in the discovery.

The supernova that exploded about 230 million years ago is officially designated Supernova 2012ha. The light from that explosion has been en route to Earth since the Triassic geologic period, when dinosaurs roamed the planet.

“That’s fairly recent as these explosions go,” Ferrante said.

Dhungana gave the nickname “Sherpa” to Supernova 2012ha.

Everest and Sherpa are two of about 200 supernovae discovered worldwide in a given year, according to the scientists.

“Everest and Sherpa aren’t noteworthy for being the youngest, oldest, closest, furthest or biggest supernovae ever observed. But both, like other supernovae of their kind, are important because they provide us with information for further science,” Ferrante said.

Read the full article.

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redOrbit: Astronomers Discover White Dwarf Supernovae

Post author By Margaret Allen
Post date March 1, 2013

The news web site redOrbit has covered the SMU Physics Department’s recent supernovae discoveries. The article, “Astronomers Discover White Dwarf Supernovae,” was published Feb. 27. Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova by SMU graduate students in the physics department.

The Central Bureau for Astronomical Telegrams of the International Astronomical Union officially designated the discoveries as Supernova 2013X and Supernova 2012ha.

Read the full article.

EXCERPT:

By Lee Rannals
redOrbit.com
White dwarf supernovae that occurred millions of years ago have popped up in the Virgo Cluster galaxy and part of the sky labelled as “anonymous.”

Southern Methodist University (SMU) researchers say they’ve confirmed two bright stars that showed up in our skies in February and November are supernovae. Supernovae are the result of stars that have reached the end of their life, resulting in a large explosion that can consume anything in its path.

In November, Farley Ferrante, a graduate student at SMU, made the initial observation of a supernova, Supernova 2012ha or “Sherpa,” that derived from the Virgo constellation, about 230 million light years away. Another supernova, Supernova 2013X or “Everest,” was discovered on February 6, sitting 450 million years away in a part of the sky labeled “animus” near the faint constellation Canes Venatici.

“Everest and Sherpa aren’t noteworthy for being the youngest, oldest, closest, furthest or biggest supernovae ever observed,” Ferrante said. “But both, like other supernovae of their kind, are important because they provide us with information for further science.”

Both supernovae are considered Type 1a, which are the result of white dwarf explosions. A white dwarf star has a mass comparable to that of the Sun and its core is a comparable size to that of the Earth. According to Robert Kehoe, physics professor and leader of the SMU astronomy team in the SMU Department of Physics, a teaspoon of a white dwarf star would weigh about as much as Mount Everest.

When a white dwarf heads towards the end of its life, it grows to about one and a half times the size of the sun and eventually collapses and explodes, resulting in a Type 1a supernova.

“We call these Type 1a supernovae standard candles,” Ferrante said. “Since Type 1a supernovae begin from this standard process, their intrinsic brightness is very similar. So they become a device by which scientists can measure cosmic distance. From Earth, we measure the light intensity of the exploded star. As star distances from Earth increase, their brilliance diminishes.”

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White dwarf supernovae are discovered in Virgo Cluster galaxy and in sky area “anonymous”

Post author By Margaret Allen
Post date February 26, 2013

Observation of two bright exploding stars improves the astronomical “tape measure” that scientists use to calculate the acceleration of the expansion of the universe

Light from two massive stars that exploded hundreds of millions of years ago recently reached Earth, and each event was identified as a supernova.

A supernova discovered Feb. 6 exploded about 450 million years ago, said Farley Ferrante, a graduate student at Southern Methodist University, Dallas, who made the initial observation.

The exploding star is in a relatively empty portion of the sky labeled “anonymous” in the faint constellation Canes Venatici. Home to a handful of galaxies, Canes Venatici is near the constellation Ursa Major, best known for the Big Dipper.

Reidus hilli, John Graf, SMU, coelacanth, Dipluridae,

A second supernova discovered Nov. 20 exploded about 230 million years ago, said Ferrante, who made the initial observation. That exploding star is in one of the many galaxies of the Virgo constellation.

The supernova that exploded about 450 million years ago is officially designated Supernova 2013X. It occurred when life on Earth consisted of creatures in the seas and oceans and along coastlines. Following naming conventions for supernova, Supernova 2013X was nicknamed “Everest” by Govinda Dhungana, an SMU graduate student who participated in the discovery.

The supernova that exploded about 230 million years ago is officially designated Supernova 2012ha. The light from that explosion has been en route to Earth since the Triassic geologic period, when dinosaurs roamed the planet. “That’s fairly recent as these explosions go,” Ferrante said. Dhungana gave the nickname “Sherpa” to Supernova 2012ha.

Type 1a supernovae help measure cosmic distances
Everest and Sherpa are two of about 200 supernovae discovered worldwide in a given year. Before telescopes, supernovae observations were rare — sometimes only several every few centuries, according to the scientists.

“Everest and Sherpa aren’t noteworthy for being the youngest, oldest, closest, furthest or biggest supernovae ever observed,” Ferrante said. “But both, like other supernovae of their kind, are important because they provide us with information for further science.”

Everest and Sherpa are Type 1a supernovae, the result of white dwarf explosions, said Robert Kehoe, physics professor and leader of the SMU astronomy team in the SMU Department of Physics.

The scientists explain that a white dwarf is a dying star that has burned up all its energy. It is about as massive as the Earth’s sun. It’s core is about the size of the Earth. The core is dense, however, and one teaspoon of it weighs as much as Mount Everest, Kehoe said.

A white dwarf explodes if fusion restarts by tugging material from a nearby star, according to the scientists. The white dwarf grows to about one and a half times the size of the sun. Unable to support its weight, Kehoe said, collapse is rapid, fusion reignites and the white dwarf explodes. The result is a Type 1a supernova.

“We call these Type 1a supernovae standard candles,” Ferrante said. “Since Type 1a supernovae begin from this standard process, their intrinsic brightness is very similar. So they become a device by which scientists can measure cosmic distance. From Earth, we measure the light intensity of the exploded star. As star distances from Earth increase, their brilliance diminishes.”

While Sherpa is a standard Type 1a, Everest is peculiar. It exhibits the characteristics of a Type 1a called a 1991T, Ferrante said.

“Everest is the result of two white dwarfs that collide, then merge,” he said.

The brightness of Sherpa’s explosion was a magnitude 16, which is far dimmer than can be seen with the naked eye. Everest’s explosion was even dimmer, a magnitude 18.

For perspective, light travels 5.88 trillion miles in a year. The sun is 93 million miles from Earth, so light from the sun reaches Earth in eight minutes.

Supernovae help in search to understand mysterious dark energy
Like other Type 1a supernovae, Everest and Sherpa provide scientists with a tiny piece to the puzzle of one of the greatest mysteries of the universe: What is dark energy?

Every Type 1a supernova provides astronomers with indirect information about dark energy, which makes up 73 percent of the mass-energy in the universe. It’s theorized that dark energy explains the accelerating expansion of our universe at various epochs after the Big Bang.

“Every exploding star observed allows astronomers to more precisely calibrate the increasing speed at which our universe is expanding,” Ferrante said. “The older the explosion, the farther away, the closer it was to the Big Bang and the better it helps us understand dark energy.”

Hobby-Eberly spectrogram confirms discovery of supernovae
Everest’s discovery was confirmed by a spectrogram obtained Feb. 10 with the Hobby-Eberly Telescope, also at McDonald Observatory. Everest is located in a host galaxy identified as 2286144 in the Principal Galaxies Catalog.

A spectrogram obtained Nov. 29 with the Hobby-Eberly Telescope confirmed Sherpa’s discovery in one of the many galaxies of the Virgo Cluster.

The Central Bureau for Astronomical Telegrams of the International Astronomical Union officially designated the discoveries as Supernova 2013X and Supernova 2012ha.

The telescope, ROTSE, constantly scans the skies for any significant changes, such as supernovae, novae and variable stars. Data from the telescope are reviewed daily by Ferrante, Dhungana and other scientists on the team, who search for signs of stellar activity.

Until now, primary responsibility for the management and operation of ROTSE3b was held by the University of Michigan. The SMU team took over that responsibility starting in Fall 2012. The ownership transfer will be completed by summer 2013, said SMU’s Kehoe.

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SMU and other members of a scientific consortium prepare for installation of the Dark Energy Spectroscopic Instrument to survey the night sky from a mile-high mountain peak in Arizona

Analysis of exploding star’s light curve and color spectrum reveal spectacular demise of one of the closest supernova to Earth in recent years; its parent star was so big it’s radius was 200 times larger than our sun

“You’re looking at things a long time ago in the universe, you can get a sense for the movie of the universe,” said Kehoe. “It’s the evolution of the universe.”

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A star exploded billions of years back, but the light of this explosion has just reached the earth, allowing scientists to peep into the past of the universe

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To put the age of the latest discovery into context, scientists believe the Big Bang occurred 13.81 billion years ago.

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Armed with images of the burst, astronomers can now analyze the data in order to understand more about the structure of the universe at its infancy

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Armed with images of the burst, astronomers can now analyze the data in order to understand more about the structure of the universe at its infancy

Known as a gamma-ray burst, the intense light captured in the night sky resulted from one of the biggest and hottest explosions in the universe, occurring shortly after the Big Bang.

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Observation of two bright exploding stars improves the astronomical “tape measure” that scientists use to calculate the acceleration of the expansion of the universe

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