Dr. Phil Armitage. No Place Like Home: Building Extrasolar Planets. 7:30PM Thurs. November 8, 2018.

The Russell Frank Astronomy Lecture Series
UNLV Physics and Astronomy Department
7:30PM Thursday November 8, 2018
Bigelow Physics Building 102

Revolutionary observational advances mean that extrasolar planetary systems are now two a penny, but few look like our own Solar System. The lecture will describe what we know about how planetary systems form, and highlight recent discoveries that may show planets caught in the act of forming. We will discuss the prospects for first finding, and then characterizing, other planets that could host life.

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

Dr. Mario Livio. The Golden Ratio. 7:30PM Thurs. October 18, 2018.

UNLV Physics and Astronomy Public Lecture
7:30PM Thursday October 18, 2018
Bigelow Physics Building 102

Dr. Mario Livio, an internationally known astrophysicist and best-selling author will talk about the Golden Ratio.

The number 1.618 known as “The Golden Ratio,” has fascinated scholars since antiquity. Some even considered it to be divine, and others were obsessed with it. In this talk I will describe the incredible history of this number, and its uncanny appearances, true and false, in natural phenomena, in the arts, in mathematics, and in human-created artifacts.

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

Dr Zhaohuan Zhu's paper in Astrophysical Journal featured on AAS Nova

Turbulent accretion disk density.

From the AAS Nova post, the image shows the density of a turbulent accretion disk in one of the first in-depth, three-dimensional magnetohydrodynamic simulations of a thin disk threaded by a large-scale vertical magnetic field. Accretion disks — which include everything from protoplanetary disks to disks around supermassive black holes — are notoriously challenging to model. Both small-scale turbulence and large-scale magnetic fields are thought to be critical processes governing motions within the disk, accretion of material, and launching of disk outflows — but capturing both of these different scales simultaneously in simulations is very difficult. The image above shows computations by Zhaohuan Zhu (University of Nevada, Las Vegas) and James Stone (Princeton University) that span three orders of magnitude in radius, extend all the way to the pole, and are evolved for more than 1,000 innermost orbits. The behavior the authors find is widely applicable to many different kinds of accretion disk systems.

The Article:

Zhaohuan Zhu and James M. Stone 2018 ApJ 857 34. doi:10.3847/1538-4357/aaafc9 Global Evolution of an Accretion Disk with a Net Vertical Field: Coronal Accretion, Flux Transport, and Disk Winds

Dr. Qiang Zhu published in Nature Communications

Qiang Zhu published an article, Predicting Phase Behavior of Grain Boundaries with Evolutionary Search and Machine Learning, in Nature Communications. The study of grain boundary phase transitions is an emerging field until recently dominated by experiments. Zhu, along with collaborators at Lawrence Livermore National Laboratory, developed a computational tool based on evolutionary algorithms that performs efficient grand-canonical grain boundary structure search. Its application to a model system of symmetric tilt boundaries in Cu uncovers an unexpected rich polymorphism in the grain boundary structures. The results demonstrate that the grain boundaries within the entire misorientation range have multiple phases and exhibit structural transitions, suggesting that phase behavior of interfaces is likely a general phenomenon.

doi:10.1038/s41467-018-02937-2

Dr. Zhaohuan Zhu named 2016-2017 College of Sciences Distinguished Researcher

College of Sciences 2016-2017 Distinguished Researcher Award

Dr. Zhu joined the UNLV faculty in 2016 as an assistant professor. He is a theoretical astrophysicist whose research focuses on understanding physics of astrophysical fluids, planet formation, and accretion processes in astrophysical disks around black holes, compact objects, and young stars and planets.

Dr. Zhu already has made tremendous contributions to UNLV, as evidenced by being the first UNLV scientist to earn the prestigious Sloan Research Fellowship that honors early-career scholars whose achievements mark them as the next generation of scientific leaders, as well as receiving two major research grants, including a prestigious NSF five-year early CAREER award and a three-year NASA Astrophysical Theory (ATP) grant.

Bill O'Donnell named 2016-2017 College of Sciences Distinguished Professional Staff member

2016-2017 College of Sciences Distinguished Professional Staff Award

Mr. O’Donnell has been a UNLV employee since 1996, serving as a Research Associate/Design Engineer in the Department of Physics and Astronomy.

His duties include designing computer hardware and software, designing analog and digital instruments for researchers, maintaining electronics shops, repairing equipment, teaching electronics classes, and training students. He has tirelessly contributed to the department in many ways, and has maintained the productive research activities in the department.

March 8, 2018. 7:30PM. Bigelow Physics Building 102. Mitchell C. Begelman. What Can Black Holes Do for You?

The Russell Frank Astronomy Lecture Series
UNLV Department of Physics & Astronomy

What Can Black Holes Do for You?

Professor Mitchell C. Begelman
Department of Astrophysics and Planetary Sciences
University of Colorado

Black holes are often regarded as cosmic vacuum cleaners, but it is actually rather hard to get them to eat. And when they do feed, they make a mess, disturbing their surroundings out to thousands or even millions of light years. I will explain why black holes are “fussy eaters”, and why the messes they make are important for the evolution of the Universe.

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

Dr. Dean Smith and members of Salamat Lab published in Phys. Rev. Materials

The Salamat lab has successfully demonstrated that the mineral CaCO3, under high pressure and temperature conditions, is capable of undergoing sp² -sp³ hybridization change purely in a P 2₁ /c structure—forgoing the accepted postaragonite Pmmn structure. Their newly reported work in Phys. rev. Materials has significant relevance for the storage of carbon within the Earth’s deep mantle.

Postaragonite phases of CaCO3 at lower mantle pressures
Dean Smith, Keith V. Lawler, Miguel Martinez-Canales, Austin W. Daykin, Zachary Fussell, G. Alexander Smith, Christian Childs, Jesse S. Smith, Chris J. Pickard, and Ashkan Salamat
Phys. Rev. Materials 2, 013605 (2018) – Published 31 January 2018

Prof. Bing Zhang and former UNLV students/postdocs published in Nature Publishing Group journals

Prof. Bing Zhang from Department of Physics and Astronomy published two papers in Nature Publishing Group journals recently: one in the 2018 January issue of Nature Astronomy (DOI:10.1038/s41550-017-0309-8) and the other in the upcoming issue of Nature Communications (DOI: 10.1038/s41467-018-02847-3). Both papers are led by former UNLV Ph.D. student Dr. Bin-Bin Zhang, who just finished a postdoctoral fellowship at Instituto de Astrofísica de Andalucía (IAA-CSIC), Spain (where the research reported in both papers was carried out) and joined the faculty of Nanjing University, China, as an associate professor. Prof. Zhang is the second and co-corresponding author of both papers.

In the Nature Astronomy paper, the team discovered for the first time a change of the composition of the gamma-ray burst (GRB) jet in one source, dubbed GRB 160625B. GRBs are the most luminous explosions in the universe, marking the birth of a black hole when a massive star collapses or two compact stars merge. A collimated “jet”, whose composition is poorly known, is launched from the system and travels towards earth with a speed greater than 0.99995 speed of light, which is observed as a burst of gamma-rays. In the past, there has been a debate within the community regarding whether the jet is mostly made of matter we are familiar with (which is called a “fireball”) or strong alternating magnetic and electric magnetic fields (which is called a Poynting-flux-dominated flow). The Nature Astronomy paper, which is co-authored by 54 people from 39 institutions, reported a detailed observation of a bright burst GRB 160625B, which has three clearly-separated emission episodes. A detailed analysis by the team suggests that the jet composition of the burst clearly transitions from a fireball in the first episode to a Poynting outflow in the second episode. The results shed light on the poorly known explosion mechanism of these mysterious events.

The most important discovery in astronomy in 2017 was the groundbreaking discovery of a gravitational wave event GW170817 due to the merger of two neutron stars as well as its associated short GRB 170817A and other electromagnetic counterpart emissions in multi-wavelength. The Nature Communications paper reports an independent analysis of the emission properties of GRB 170817A as well as the physical implications. This paper has 18 authors, including 4 former UNLV Ph.D. students (Drs. He Gao, Ye Li, Hou-Jun Lü besides Bin-Bin Zhang) and 3 former UNLV postdoc fellows (Drs. Wei-Hua Lei, Xue-Feng Wu, and En-Wei Liang) as the key authors. This paper nicely complements the official papers by the LIGO/Virgo gravitational wave detector team and the NASA’s Fermi Gamma-Ray Telescope team by studying the luminosity function of short GRBs as well as the possible physical mechanism that powers this unique event.