Yan Zhou's lab receives Gentec EO gift

UNLV Department of Physics & Astronomy is pleased to acknowledge the recent donation of high-tech laser measuring technology by Gentec EO. The QE-25LP is a pyroelectric laser detector that provides a reliable and accurate solution to measure high-energy pulsed lasers in our department. In addition to scientific research impact, it will also improve the laser safety.

The equipment will be housed in the research lab of Assistant Professor, Yan Zhou, in UNLV's Cold and Ultracold Molecular Ions Lab and support research efforts on: (1) exploring new physics beyond the Standard Model by precision measurements using ultracold molecular ions and (2) investigating astrochemistry by emulating the interstellar environment in the laboratory.

Russell Frank Astronomy Lecture: Francis Halzen: IceCube: A Neutrino Window on the Universe. Thursday February 23, 2023 7:30PM. Bigelow Physics Building 102.

Francis Halzen: IceCube: A Neutrino Window on the Universe

The IceCube project at the South Pole melted 86 holes over 1.5 miles deep, in the Antarctic icecap, to construct an enormous observatory. The experiment discovered a flux of neutrinos reaching us from the cosmos, with energies more than a million times those of neutrinos produced at accelerator laboratories. These cosmic neutrinos are astronomical messengers from the extreme universe that is opaque to light. We discuss the IceCube telescope and recent discoveries that some high-energy neutrinos originate from sources powered by supermassive black holes.

This talk is intended for a general audience including enthusiasts of all backgrounds and ages.

The mission of the Russell Frank Astronomy Lecture Series is to bring distinguished scientists to UNLV to present lectures aimed at communicating cutting edge science to the general public. The lectures are free and are held once each semester. They are intended for a general audience and we encourage enthusiasts of all backgrounds and ages to attend.

The sponsor of the series, Russell Frank, is a New Jersey native who has multiple degrees and has taught at several prestigious institutions. Frank says: "I have enjoyed the various courses I have taken at UNLV and providing the astronomy and physics lecture series to the community is my way of giving back to the university."

Astrophysicists from UNLV and Nanjing University revise theoretical framework of Gamma Ray Bursts

Tony Allen from UNLV News Center summarized the work.

The mysteries of the cosmos continue to amaze astronomers, and with each new observation comes a chance to deepen – or upend – our understanding of the universe.

In the Dec. 7 issue of the journal Nature, an international team of astrophysicists report the discovery of a unique cosmological gamma-ray burst (GRB) that defies prevailing theories of how the violent cosmic explosions form. This “oddball” burst led the team to propose a new model, or source, for certain types of GRBs.

Gamma-ray bursts are the most luminous and violent explosions in the universe. They signify the deaths of stars or collisions of stellar remnants. Observed GRBs are typically placed into two categories: short- or long-duration GRBs. Long GRBs originate from the deaths of massive stars, and are typically associated with bright optical transients named supernovae. Short GRBs have a duration of less than two seconds and originate from the collisions of two neutron stars or a neutron star and a black hole, and are typically associated with more faint optical transients known as kilonovae.

For decades, GRBs nestled nicely into these cozy categories. Until now.

On Dec.11, 2021, a GRB triggered several gamma-ray detectors in space, including NASA’s Fermi Gamma-ray Telescope and the Neil Gehrels Swift Observatory. This burst, with a duration of nearly 70 seconds, would typically be regarded as a normal long GRB. That is, until multiple teams from the U.S. and Europe performed follow-up observations and discovered a surprising signature.

“This GRB includes two parts: a 13-second long hard spike and a 55-second softer extended emission,” said UNLV alumnus and study corresponding author Bin-Bin Zhang, who’s currently with China’s Nanjing University. “The duration of the 13-second hard spike should have completely excluded this burst from the short GRB category.”

In other words, instead of showing a much brighter supernova, as expected, the observation was consistent with a kilonova that is more typically associated with a short GRB.

“Such a peculiar GRB was the first of its kind ever detected,” said UNLV astrophysics professor Bing Zhang, co-corresponding-author of the Nature paper. “This discovery not only challenged our understanding of GRB origins, it also requires us to consider a new model for how some GRBs form.”

The research team believes that this unique GRB, known as GRB 211211A, likely formed through collision between a neutron star and a white dwarf, what’s known as a WD-NS merger.

White dwarfs are earth-sized objects that form from the death of low-mass stars – those with a mass smaller than that of about eight of our Suns. Neutron stars form when more massive stars, those with a mass of between about eight and 20 Suns, die off. When even larger stars die, they form black holes directly.

Massive, low-density stars make long-duration GRBs whereas high-density stars, including neutron stars, make short duration GRBs. According to UNLV’s Zhang, white dwarfs have intermediate densities, which make them ideal origins for the type of GRB discovered in 2021 as it displays an intermediately long duration without involving a massive star.

“Despite the relatively large number of GRBs observed each year, the unique signature of GRB 211211A pushed the envelope of our current categorial systems and required a new way of thinking,” said Zhang. “After careful review, the only merger scenario that made sense was that of a white dwarf and neutron star.”

UNLV doctoral student Shunke Ai and a student from Nanjing University collaborated to develop a detailed model to interpret the peculiar kilonova signature observed by GRB 211211A. Ai found that if a WD-NS merger leaves behind a rapidly spinning neutron star, known as a magnetar, the additional energy injection from the magnetar combined with the nuclear reaction energy from the material thrown during the burst can account for the kilonova emission observed for GRB 211211A. About the Study

The study, “A long-duration gamma-ray burst with a peculiar origin”, appeared Dec. 7 in the journal Nature. The paper includes 10 co-authors from 4 institutions, with UNLV and Nanjing University being the lead institutions. Published in the same issue are three parallel papers that report the detection of the kilonova. This paper focuses on the peculiar gamma-ray emission itself and proposes the WD-NS merger model to interpret the data.

 

(Image credit: Anyu Lei and Jing Chen, Nanjing University School of Arts)

International Team of Astronomers closer to an understanding of Fast Radio Bursts

Author: Tony Allen from UNLV News Center.

Nearly 15 years after the discovery of fast radio bursts (FRBs), the origin of the millisecond-long, deep-space cosmic explosions remains a mystery.

That may soon change, thanks to the work of an international team of scientists – including UNLV astrophysicist Bing Zhang – which tracked hundreds of the bursts from five different sources and found clues in FRB polarization patterns that may reveal their origin. The team’s findings were reported in the March 17 issue of the journal Science.

FRBs produce electromagnetic radio waves, which are essentially oscillations of electric and magnetic fields in space and time. The direction of the oscillating electric field is described as the direction of polarization. By analyzing the frequency of polarization in FRBs observed from various sources, scientists revealed similarities in repeating FRBs that point to a complex environment near the source of the bursts.

“This is a major step towards understanding the physical origin of FRBs,” said Zhang, a UNLV distinguished professor of astrophysics who coauthored the paper and contributed to the theoretical interpretation of the phenomena.

To make the connection between the bursts, an international research team, led by Yi Feng and Di Li of the National Astronomical Observatories of the Chinese Academy of Sciences, analyzed the polarization properties of five repeating FRB sources using the massive Five-hundred-meter Aperture Spherical radio Telescope (FAST) and the Robert C. Byrd Green Bank Telescope (GBT). Since FRBs were first discovered in 2007, astronomers worldwide have turned to powerful radio telescopes like FAST and GBT to trace the bursts and to look for clues on where they come from and how they’re produced.

Though still considered mysterious, the source of most FRBs is widely believed to be magnetars, incredibly dense, city-sized neutron stars that possess the strongest magnetic fields in the universe. They typically have nearly 100% polarization. Conversely, in many astrophysical sources that involve hot randomized plasmas, such as the Sun and other stars, the observed emission is unpolarized because the oscillating electric fields have random orientations.

That’s where the cosmic detective work kicks in.

In a study the team originally published last year in Nature, FAST detected 1,652 pulses from the active repeater FRB 121102. Even though the bursts from the source were discovered to be highly polarized with other telescopes using higher frequencies – consistent with magnetars – none of the bursts detected with FAST in its frequency band were polarized, despite FAST being the largest single-dish radio telescope in the world.

“We were very puzzled by the lack of polarization,” said Feng, first author on the newly released Science paper. “Later, when we systematically looked into other repeating FRBs with other telescopes in different frequency bands – particularly those higher than that of FAST, a unified picture emerged.”

According to Zhang, the unified picture is that every repeating FRB source is surrounded by a highly magnetized dense plasma. This plasma produces different rotation of the polarization angle as a function of frequency, and the received radio waves come from multiple paths due to scattering of the waves by the plasma.

When the team accounted for just a single adjustable parameter, Zhang says, the multiple observations revealed a systematic frequency evolution, namely depolarization toward lower frequencies.

“Such a simple explanation, with only one free parameter, could represent a major step toward a physical understanding of the origin of repeating FRBs,” he says.

Di Li, a corresponding author of the study, agrees that the analysis could represent a corner piece in completing the cosmic puzzle of FRBs. “For example, the extremely active FRBs could be a distinct population,” he says. “Alternatively, we’re starting to see the evolutionary trend in FRBs, with more active sources in more complex environments being younger explosions.”

The study, “Frequency-dependent polarization of repeating fast radio bursts—implications for their origin,” appeared March 17 in the journal Science. It includes 25 co-authors from 11 institutions and is part of long-running collaboration among institutions. In addition to UNLV and NAOC, collaborating institutions also include Yunnan University, Princeton University, Western Sidney University, Peking University and Green Bank Observatory, USA. 

(Image credit: Jingchuan Yu, Beijing Planetarium)

International Team of Astronomers Reports on Largest-ever Observed Set of Mysterious Fast Radio Bursts

Reported by Tony Allen in UNLV News Center.

An international team of astronomers recently observed more than 1,650 fast radio bursts (FRBs) detected from one source in deep space, which amounts to the largest set – by far – of the mysterious phenomena ever recorded.

More than a decade after the discovery of FRBs, astronomers are still baffled by the origins of the millisecond-long, cosmic explosions that each produce the energy equivalent to the sun’s annual output.

In a study published in the Oct. 13 issue of the journal Nature, scientists – including UNLV astrophysicist Bing Zhang – report on the discovery of a total of 1,652 independent FRBs from one source over the course of 47 days in 2019. The source, dubbed FRB 121102, was observed using the Five-hundred-meter Aperture Spherical Telescope (FAST) in China, and represents more FRBs in one event than all previous reported occurrences combined.

“This was the first time that one FRB source was studied in such great detail,” said Zhang, one of the study’s corresponding authors. “The large burst set helped our team hone in like never before on the characteristic energy and energy distribution of FRBs, which sheds new light on the engine that powers these mysterious phenomena.”

Since FRBs were first discovered in 2007, astronomers worldwide have turned to powerful radio telescopes like FAST to trace the bursts and to look for clues on where they come from and how they’re produced. The source that powers most FRBs is widely believed to be magnetars, incredibly dense, city-sized neutron stars that possess the strongest magnetic fields in the universe. And while scientists are gaining greater clarity on what produces FRBs, the exact location of where they occur is still a mystery.

A mystery that recent results may be starting to unravel.

According to Zhang, there are two active models for where FRBs come from. One could be that they come from magnetospheres, or within a magnetar’s strong magnetic field. Another theory is that FRBs form from relativistic shocks outside the magnetosphere traveling at the speed of light.

“These results pose great challenges to the latter model,” says Zhang. “The bursts are too frequent and - given that this episode alone amounts to 3.8% of the energy available from a magnetar - it adds up to too much energy for the second model to work.”

The bursts were measured by FAST within a total of 59.5 hours over 47 days from Aug. 29 to Oct. 29, 2019. 

“During its most active phase, FRB 121102 included 122 bursts measured within a one-hour period, the highest repeat rate ever observed for any FRB,” said Pei Wang, one of the article’s lead authors from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC).

Researchers expect that FAST will continue to systematically investigate a large number of repeating FRBs in the future.

“As the world’s largest antenna, FAST’s sensitivity proves to be conducive to revealing intricacies of cosmic transients, including FRBs,” said Di Li, the study’s lead researcher from NAOC.

The study includes more than 30 co-authors from 16 institutions in four countries and is part of a long-running collaboration among the institutions. In addition to UNLV and NAOC, collaborating institutions include Guizhou Normal University, Cornell University, Max Planck Institute for Radio Astronomy, West Virginia University, CSIRO Astronomy and Space Science, University of California Berkeley, and Nanjing University.

Publication Details: “A bimodal burst energy distribution of a repeating fast radio burst source,” was published in the Oct. 13, 2021 issue of the journal Nature.

Professor Monika Mościbrodzka. Imaging Magnetic Fields at the Edge of M87's Black Hole. Thursday April 29, 2021 at 7PM PDT (ONLINE).

The Russell Frank Astronomy Lecture Series
UNLV Physics and Astronomy Department
7:00PM PDT Thursday April 29, 2021
2:00AM GMT Friday April 30, 2021
Webex link https://unlv.webex.com/unlv/j.php??MTID=m9b77c4799c5efce726b9afdbd984e08a

Two years ago, scientists presented the first image of a black hole at the center of a galaxy. We see a bright ring formed as light bends in the intense gravity around a black hole that is 6.5 billion times more massive than the Sun. Last month, for the first time, observations revealed the signature of magnetic fields close to the edge of a black hole. These new images are the key to explaining how the black hole is able to launch energetic jets. Dr. Mościbrodzka will discuss how these images of the black hole were made and their meaning.

This talk is intended for a general audience including enthusiasts of all backgrounds and ages.

Bing Zhang contributes to understanding the physical mechanisms of fast radio bursts in three papers published in Nature.

Authored by Shane Bevell for the UNLV News Center, November 4, 2020.

Fast radio bursts, or FRBs – powerful, millisecond-duration radio waves coming from deep space outside the Milky Way Galaxy – have been among the most mysterious astronomical phenomena ever observed. Since FRBs were first discovered in 2007, astronomers from around the world have used radio telescopes to trace the bursts and look for clues on where they come from and how they’re produced.

UNLV astrophysicist Bing Zhang and international collaborators recently observed some of these mysterious sources, which led to a series of breakthrough discoveries reported in the journal Nature that may finally shed light into the physical mechanism of FRBs.

The first paper, for which Zhang is a corresponding author and leading theorist, was published in the Oct. 28 issue of Nature.

“There are two main questions regarding the origin of FRBs,” said Zhang, whose team made the observation using the Five-hundred-meter Aperture Spherical Telescope (FAST) in Guizhou, China. “The first is what are the engines of FRBs and the second is what is the mechanism to produce FRBs. We found the answer to the second question in this paper.”

Two competing theories have been proposed to interpret the mechanism of FRBs. One theory is that they’re similar to gamma-ray bursts (GRBs), the most powerful explosions in the universe. The other theory likens them more to radio pulsars, which are spinning neutron stars that emit bright, coherent radio pulses. The GRB-like models predict a non-varying polarization angle within each burst whereas the pulsar-like models predict variations of the polarization angle.

The team used FAST to observe one repeating FRB source and discovered 11 bursts from it. Surprisingly, seven of the 11 bright bursts showed diverse polarization angle swings during each burst. The polarization angles not only varied in each burst, the variation patterns were also diverse among bursts.

“Our observations essentially rules out the GRB-like models and offers support to the pulsar-like models,” said K.-J. Lee from the Kavli Institute for Astronomy and Astrophysics, Peking University, and corresponding author of the paper.

Four other papers on FRBs were published in Nature on Nov. 4. These include multiple research articles published by the FAST team led by Zhang and collaborators from the National Astronomical Observatories of China and Peking University. Researchers affiliated with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and the Survey for Transient Astronomical Radio Emission 2 (STARE2) group also partnered on the publications.

“Much like the first paper advanced our understanding of the mechanism behind FRBs, these papers solved the challenge of their mysterious origin,” explained Zhang.

Magnetars are incredibly dense, city-sized neutron stars that possess the most powerful magnetic fields in the universe. Magnetars occasionally make short X-ray or soft gamma-ray bursts through dissipation of magnetic fields, so they have been long speculated as plausible sources to power FRBs during high-energy bursts.

The first conclusive evidence of this came on April 28, 2020, when an extremely bright radio burst was detected from a magnetar sitting right in our backyard – at a distance of about 30,000 light years from Earth in the Milky Way Galaxy. As expected, the FRB was associated with a bright X-ray burst.

“We now know that the most magnetized objects in the universe, the so-called magnetars, can produce at least some or possibly all FRBs in the universe,” said Zhang.

The event was detected by CHIME and STARE2, two telescope arrays with many small radio telescopes that are suitable for detecting bright events from a large area of the sky.

Zhang’s team has been using FAST to observe the magnetar source for some time. Unfortunately, when the FRB occurred, FAST was not looking at the source. Nonetheless, FAST made some intriguing “non-detection” discoveries and reported them in one of the Nov. 4 Nature articles. During the FAST observational campaign, there were another 29 X-ray bursts emitted from the magnetar. However, none of these bursts were accompanied by a radio burst.

“Our non-detections and the detections by the CHIME and STARE2 teams delineate a complete picture of FRB-magnetar associations,” Zhang said.

To put it all into perspective, Zhang also worked with Nature to publish a single-author review of the various discoveries and their implications for the field of astronomy.

“Thanks to recent observational breakthroughs, the FRB theories can finally be reviewed critically,” said Zhang. “The mechanisms of producing FRBs are greatly narrowed down. Yet, many open questions remain. This will be an exciting field in the years to come.”

Read More

• "No pulsed radio emission during a bursting phase of a Galactic magnetar," published in the Nov. 4 issue of Nature.
• "The physical mechanisms of fast radio bursts," published in the Nov. 4 issue of Nature.
• "Diverse polarization angle swings from a repeating fast radio burst source," published in the Oct. 28 issue of Nature.

Ashkan Salamat's research about room-temperature superconductivity is one of 10 finalists in Physics World magazine's Breakthrough of the Year for 2020.

Ashkan Salamat's recent research about room-temperature superconductivity with colleague Ranga Dias from the University of Rochester was announced as one of 10 finalists in Physics World magazine's Breakthrough of the Year for 2020.

The announcement of the Breakthrough of the Year will be made Dec. 17.

This year’s Top 10 Breakthroughs were selected by a crack team of five Physics World editors, who have sifted through hundreds of research updates published on the website this year. In addition to having been reported in Physics World in 2020, selections must meet the following criteria:

• Significant advance in knowledge or understanding
• Importance of work for scientific progress and/or development of real-world applications
• Of general interest to Physics World readers

Rebecca Martin awarded NASA Exoplanets grant

Associate professor of Physics & Astronomy, Rebecca Martin, is the prinicipal investigator on a NASA Exoplanets grant that was awarded for $541,460 to study planet formation in binary star systems. Since most stars are in binaries, we need to understand how the binary affects the planet formation process in order to explain the properties of observed exoplanets.

Daniel Proga awarded NASA TCAN grant

Professor of Physics and Astronomy Daniel Proga was just awarded one of NASA's most prestigious research grants through the Theoretical and Computational Astrophysics Networks (TCAN) program. The grant totals $1,547,537 and will be shared with 4 other major research institutions: the Institute for Advanced Study, NASA's Goddard Space Flight Center, The University of Virginia, and the Flatiron Institute at the Center for Computational Astrophysics.

Professor Proga is the principal investigator and hence UNLV will be the head node of this network collaboration to advance the state of the art in modeling accretion processes in astrophysics. Specifically, the collaboration will develop algorithms and perform supercomputer simulations to understand exactly how the atmospheres of turbulent accretion disks should appear observationally, according to theory. It is well known that disk atmospheres around systems such as supermassive black holes and low mass X-ray binaries can be unbound, forming accretion disk winds. Professor Proga has spent much of his career understanding such disk winds, and this emphasis is apparent in the name of the collaboration: A New DAWN (Disk Accretion and Winds Network). The name also reflects the ambitious goals of the project, as the resulting modeling capability is expected to usher in a new dawn in understanding the physics of how matter is accreted and ejected from black holes, neutron stars, and newly born stars. The full UNLV team consists of Associate Professor of Physics and Astronomy and co-investigator Zhaohuan Zhu, Postdoctoral Researcher Tim Waters (who earned his PhD from UNLV in 2017), and graduate students Randall Dannen and Shalini Ganguly. This major grant will provide funding support for this team for a period of three years in addition to supporting two other postdoctoral researchers and several graduate students at the partnering research institutions.

Chao-Chin Yang awarded NASA TCAN grant

Assistant research professor Chao-Chin Yang was awarded a multi-institutional research grant by NASA through the Theoretical and Computational Astrophysics Networks (TCAN) program. Led by New Mexico State University, other collaborators include UNLV, University of Arizona, Iowa State University, and SETI Institute in the United States, and Max Planck Institute for Astronomy in Germany. Yang is a co-I/Institutional PI and will lead the UNLV node on the project. The grant totals $1.3 million with UNLV receiving $185,000. The team will investigate the influence of gas and dust dynamics in the protoplanetary disk around a newborn star on the formation of kilometer-scale planetary bodies — such as asteroids and comets in our own solar system — which are important intermediate building blocks of planets.

This award brings UNLV Physics & Astronomy's total active Theoretical and Computational Astrophysics Networks (TCAN) program awards to three. Meaning we have more active TCAN programs than any other institution in the US.

Ashkan Salamat and colleagues at UNLV and University of Rochester observe room-temperature superconductivity

Reported from the UNLV News Center press release release October 14 2020, Author: Natalie Bruzda.

Physicists from the University of Nevada, Las Vegas and the University of Rochester have made a breakthrough in the long sought-after quest for a room-temperature superconductor, what they call the “holy grail” of energy efficiency.

The research team led by University of Rochester physicist Ranga Dias in collaboration with Ashkan Salamat, assistant professor of physics and astronomy at UNLV, established room temperature superconductivity in a diamond anvil cell - a small, handheld, and commonly used research device that enables the compression of tiny materials to extreme pressures - pressures that you’d only find at the center of the Earth.

Though the phenomena observed by the research team and reported today as the cover story in the journal Nature was at an early stage, or fundamental level, the discovery has implications for how energy is stored and transmitted. It could also one day change how everyday technological devices - from laptops to MRI machines - are powered, how people and goods are transported, and how the whole of society could operate years into the future.

“It’s a revolutionary game changer,” said Salamat, who leads the Nevada Extreme Conditions Lab at UNLV, a newly formed, multidisciplinary group that explores fundamental experimental, computational, and engineering problems of materials under high pressure. “The discovery is new, and the technology is in its infancy and a vision of tomorrow, but the possibilities are endless. This could revolutionize the energy grid, and change every device that’s electronically driven.”

Superconductivity is a remarkable quantum phenomena as its hallmark properties include the expulsion of magnetic fields and zero resistance electrical flow, meaning that the energy current passing through a circuit is conducted infinitely and perfectly, with no loss of power.

Since its first observation in 1911, scientists have observed superconductivity only at very low temperatures — temperatures within a few degrees of absolute zero, (minus 273 degrees Celsius), which would make widespread and practical application unattainable. In 1968, however, scientists predicted that metallic hydrogen - accessed at very high pressures - could be the key ingredient to discovering superconductivity at or above room temperature.

"Because of the limits of low temperature, materials with such extraordinary properties have not quite transformed the world in the way that many might have imagined. However, our discovery will break down these barriers and open the door to many potential applications," Dias said in a University of Rochester release.

In Dias’ lab at the University of Rochester, the research team worked to chemically synthesize hydrogen in an effort to solve the century-old problem. Like a materials search engine, Salamat and Dias used the diamond anvil cell to scan through temperature and pressure space to find the right combination that would drive carbon sulfur hydrogen first into a metallic state, and then even further into a room-temperature superconducting state.

The U.S. energy grid, Salamat notes, which is made up of metallic cables loses about $20 billion a year to dissipating current. Though a metal like copper exhibits the least resistance of nearly all metals, it’s still resistant. Running current through copper and other metals generates heat, and as a consequence energy is lost (think of the heat exiting the bottom of your laptop).

Room-temperature superconductivity would allow current to flow through a closed loop forever, meaning that no energy would be lost. In the long distant future, such a state could enable a solar farm in the Southwest U.S. to transport energy to the East Coast with no loss, or MRI machines - which currently need liquid helium to operate - to be deployed to war zones. It could change how electronics are designed and built, and could revolutionize the transportation system.

Salamat calls it a “paradigm-shifting” discovery, which was made possible, in part, by the Early Career Award he received from the U.S. Department of Energy in 2019. The competitive DOE program bolsters financial support for exceptional talent during crucial early career years, when many scientists do their most formative work, and was the catalyst for Salamat to focus on the problem of identifying a room-temperature superconductor.

The discovery also dovetails perfectly into Salamat’s broader research priorities, which are identifying the precise makeup of metal superhydrides – extremely hydrogen-rich materials – and techniques to readily synthesize them.

The discovery of the room-temperature superconductor, Salamat said, was not what you would call a “eureka” moment, but rather, a methodical, targeted effort by he and Dias. They’re next step is to develop a protocol that releases the pressure for these materials while also retaining their superconducting properties.

To support their continued work on the problem, Dias and Salamat have started a new company, Unearthly Materials, to find a path to room temperature superconductors that can be produced at scale at ambient pressure.

“We live in a semiconductor society,” Salamat said. “With this kind of technology, you can take society from a semi-conducting society into a superconducting society.”

Coauthors on the Nature paper include Keith Lawler of UNLV's Nevada Extreme Conditions Lab; Elliot Snider, Nathan Dasenbrock-Gammon, Raymond McBride, Kevin Vencatasamy and Hiranya Vindana, all of the Dias lab at the University of Rochester; and Mathew Debessai of Intel Corporation.

Here is the publication in Nature where it was a cover feature. Room-temperature superconductivity in a carbonaceous sulfur hydride

The discovery has been widely reported including in these publications: Nature News, MIT Technology Review, Quanta magazine, Science magazine, New York Times, Nature podcast.

Additionally here is a nice interview with Ranga and Ash on Liv Boeree's Youtube channel.

Tim Waters appointed to working group on Athena X-Ray Observatory

Tim Waters has been appointed to be a member of the Athena X-Ray Observatory topical panel: SWG2.5: Physics of accretion, co-chaired by C. Done, J. Miller and C. Motch; this panel forms part of the SWG2: Energetic Universe working group, co-chaired by J. Aird, L. Brenneman and M. Cappi.

The Athena mission is scheduled to launch in 2031 and Tim as a member of the Physics of accretion working group aims to apply the simulations of X-ray binaries developed with Daniel Proga to make detailed predictions of the X-ray absorption lines that Athena should be able to resolve.

Athena Mission concept

The Athena mission will be a large X-ray observatory offering spatially-resolved X-ray spectroscopy and deep wide-field X-ray spectral imaging with performance greatly exceeding that offered by current X-ray observatories like XMM-Newton and Chandra, or by missions like Hitomi, XARM, and SRG/eROSITA.

Athena will be launched by an Ariane 6 vehicle, with equivalent or larger lift capability and fairing size to that of the Ariane 5 ECA. It will operate at the second Sun-Earth Lagrangian point (L2) in a large halo orbit, although the possibility of an L1 halo orbit is also being assessed. The operational orbit will be reached with a direct transfer trajectory towards L2, with limited delta-V demands, and it offers a very stable thermal environment as well as good instantaneous sky visibility and high observing efficiency.

Athena has a baseline mission lifetime of 4 years, although it is expected to be designed and have consumables for a longer time. Operations will be performed as in standard ESA science missions, with the Mission Operations Centre (MOC) at ESOC and the Science Operations Centre (SOC) at ESAC. The Instrument and Science Centre (ISC) associated with each of the two instruments will be in support of the SOC with regard to science ground segment activities.

Athena will be operated as an observatory, in a similar fashion to prior missions such as XMM-Newton and Herschel. Users will access the observatory via open proposal calls.

Science requirements

A detailed analysis of the scientific questions underlying the Hot and Energetic Universe theme sets the key performance parameters for the mission. Mapping the dynamics and chemical composition of hot gas in diffuse sources requires high spectral resolution (2.5 eV) imaging with large area and low background; the same capabilities also optimize the sensitivity to weak absorption and emission features needed to uncover the hot components of the intergalactic medium. High resolution X-ray spectroscopy of distant gamma-ray bursts (GRBs) will reveal the signature of the first generation of stars, provided that the observatory can be repointed within 4 hours of an external trigger. An angular resolution lower than 5” (Half Energy Width) is needed to disentangle contaminants (point-source and sub-clump) from extended thermal emission in clusters, groups and galaxies. The same angular resolution is needed to resolve the dominant core emission and smaller accreting structures in galaxy clusters and groups up to redshift z~2. This resolution, when combined with the mirror effective area, also provides the necessary flux sensitivity (~10-17 erg cm-2 s-1 in the 0.5-2 keV band) to uncover typical accreting SMBH at z>6. The area coverage needed to detect significant samples of these objects within a reasonable survey time demands a large field of view instrument, combined with excellent off-axis response for the X-ray optics. The spectral resolution of that instrument will reveal the most obscured black holes at the peak of the Universe’s activity at z=1-4. High timing resolution and high-count rate capability will shed new light on nearby accreting black hole systems.

Dr. Mario Livio. GALILEO and the Science Deniers. Thursday October 8, 2020 at 7PM PDT (ONLINE).

The Russell Frank Astronomy Lecture Series
UNLV Physics and Astronomy Department
7:00PM PDT Thursday October 8, 2020
2:00AM GMT Friday October 9, 2020
https://unlv.webex.com/unlv/j.php?MTID=me812ab108708bbf4c6ec830543909eff

A fresh biography of Galileo Galilei which puts his scientific discoveries in context.

Disturbed by rampant science denial in America—and around the world—that has only intensified in recent years, I began researching the life, ideas, and actions of this brilliant man who encountered similar pressures centuries ago. The result is a biography filled with lessons relevant for today—whether with respect to the COVID-19 pandemic, climate change, the efficacy of vaccines, or the teaching of creationist theories in schools. I will discuss a few of these topics in this talk.

Dr. Mario Livio is an internationally renowned astrophysicist, a best-selling author, and a popular speaker.

He is a Fellow of the American Association for the Advancement of Science.

He has published more than 400 scientific papers on topics ranging from Dark Energy and cosmology to black holes and extrasolar planets.

Dr Livio is also the author of seven popular science books, including "The Golden Ratio" (an International Bestseller for which he received the "Peano Prize" and the "International Pythagoras Prize”). Livio's book "Brilliant Blunders" was a national bestseller in the U.S., and was selected by the Washington Post as one of the " Best Books of the Year.”

His new book, “Galileo and the Science Deniers,”was published in May 2020 and received rave reviews in The Washington Post, the London Times, and many more.

Randall Dannen's work featured on NASA web site.

Why Clouds Form Near Black Holes

An article by by Elizabeth Landau, senior communications specialist with NASA summarizes Randall Dannen's recent work on the physics of active galactic nuclei in Daniel Proga's research group. Read the NASA website article here. and Randall's original paper here.

May 11, 2020 1:00PM PDT. Emily Siska dissertation defense: Investigations of technetium metal and the synthesis of binary technetium nitrides under extreme conditions

Investigations of technetium metal and the synthesis of binary technetium nitrides under extreme conditions Emily Siska
Ph.D. Candidate, Department of Chemistry and Biochemistry

This work investigates the structural and chemical stability of technetium under extreme conditions using in situ synchrotron X-ray diffraction. Utilizing advanced pressure and laser heating techniques we are able to access different regimes of the energy landscapes unexplored by previous studies. There are two sets of study; both of which are fundamental to understanding the physical and chemical behavior of this radioactive transition element. The first, is the discovery and characterization of a new, high pressure high temperature allotrope of Tc. Through structural analysis, we are able to demonstrate the existence of magnetic ordering - only the second example in a 4d metal. The second, is the synthesis of a new family of nitride compounds whose physical properties are explored.

The defense presentation is open to the public via Webex conference meeting hosted by Dr. Ashkan Salamat.

Monday, May 11, 2020 1:00 pm | 1 hour | (UTC-07:00) Pacific Time (US & Canada)
Meeting number: 289 418 495
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Randall Dannen published in Astrophysical Journal Letters.

PhD student Randall Dannen (College of Sciences, CoS) has recently demonstrated a novel method to create clouds around black holes. To appear in May as a Letter in the prestigious Astrophysical Journal, this work, led by Dannen, was co-authored with Prof. Daniel Proga (Dannen’s PhD adviser), Drs. Tim Waters (CoS) and Sergei Dyda (the University of Cambridge). It combines methodology from both observational and theoretical disciplines to address an outstanding problem in the field of Active Galactic Nuclei (AGN).

At the center of every massive galaxy, there exists a supermassive black hole (SMBH). When the gas around these SMBHs starts to fall in, it shines exceptionally bright. In fact, AGN are the most energetic long-lived objects in the universe. As a consequence of this immense release of energy, some material that is falling onto SMBHs can be ejected, forming AGN winds. These winds can extend all the way out to galactic scales, where astronomers see that rather than the flow being smooth, there exist discrete clumps. However, it has been challenging to form these clouds in state of the art computational models. Thus, this discovery of how to form clouds in numerical simulations is a major development.

Here is a link to the paper Clumpy AGN Outflows due to Thermal Instability and to the project website http://www.physics.unlv.edu/astro/clumpywindsims.html.

April 17, 2020 11:00AM PDT. Christian Childs dissertation defense: Development of CO2 laser-heating for the study of wide band gap oxide materials.

Development of CO2 laser-heating for the study of wide band gap oxide materials
Christian Childs
Ph.D. Candidate, Department of Physics and Astronomy

The ability to access a vast region of the pressure-temperature landscape using energy density tuning enables exotic states of matter to be probed. A well documented method for such exploration, under static conditions, is the use of the laser-heated diamond anvil cell (LH-DAC), utilizing a combination of high pressure (> 300 GPa) and high temperature (> 5000 K). Combining the LH-DAC with in situ synchrotron techniques utilizes characterization methods to measure structural and electronic responses at these extreme conditions.

The wavelength of the laser source defines the type of interaction with the sample that occurs, with metals typically being heated using near-IR light through an inverse-Bremsstrahlung process, while insulators are transparent at these wavelengths and must be coupled with mid-IR light through anharmonic polariton-phonon scattering processes. This technique of directly heating insulators is under developed and poorly understood.

I will present our development of CO2 laser heating techniques to directly heat a series of wide band gap insulators, La2Sn2O7, ZrO2, and CeO2, under high pressure conditions. As the emissivity of insulators are poorly constrained under extreme conditions, limiting optical pyrometry techniques, I will present a series of new, powerful tools for determining the absolute temperature of such systems. In addition to demonstrating the design of instrumentation here at UNLV I will present two dedicated laser heatings systems at Argonne National Laboratory's Advanced Photon Source at sector 16-IDB for in-situ x-ray diffraction and at sector 16-BMD for in-situ x-ray absorption spectroscopy. Both of these instruments are the first of their kind, permitting the direct probing of warm dense matter and providing the scientific community with the tools of tomorrow.

Committee Members:
Dr. Ashkan Salamat, Advisory Committee Chair
Dr. David Shelton, Advisory Committee Member
Dr. Andrew Cornelius, Advisory Committee Member
Dr. Paul Forster, Graduate College Representative

The defense presentation is open to the public via Webex conference meeting hosted by Dr. Ashkan Salamat

Friday, Apr 17, 2020 11:00 am | 1 hour | (UTC-07:00) Pacific Time (US & Canada)
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Chao-Chin Yang, Zhaohuan Zhu, Stephen Lepp, and Xiao Hu receive NASA Astrophysics Theory Program grant

Chao-Chin Yang, Zhaohuan Zhu, Stephen Lepp, and Xiao Hu just were awarded a $474,315 research grant by NASA through the Astrophysics Theory Program. They will conduct state-of-the-art computer simulations to model a circumstellar disk around a young star and study the dust-gas dynamics in the disk. The investigation will help us understand the variety of morphological features such as rings and gaps in nearby circumstellar disks detected recently by high-resolution, high-contrast observations. It will also improve the understanding of the process of planet formation. Zhu and Lepp are co-investigators on the project, and Hu is a collaborator.

The text courtesy an original announcement in UNLV Today.

Chao-Chin Yang, Zhaohuan Zhu and Stephen Lepp receive NASA Emerging Worlds Program grant

Chao-Chin Yang, Zhaohuan Zhu and Stephen Lepp just were awarded a $456,315 research grant by NASA through the Emerging Worlds Program. They will investigate one of the most difficult stages in the course of planet formation, for example, how kilometer-scale planetesimals can be built from pebble-sized materials around a young star before a planet can be fully assembled. By conducting state-of-the-art computer simulations and comparing the results with the properties of the Kuiper Belt objects observed in our own solar system, they will be able to test the leading theory of planetesimal formation at unprecedentedly high resolutions. The investigation will further improve our understanding of the origins of the solar system as well as the thousands of the extrasolar planetary systems. Zhu and Lepp are co-investigators on the project.

The text courtesy an original announcement in UNLV Today.