Department in the News: 2019
Astronomers May Have Detected Neutron Star Being Consumed by Black Hole
May 15, 2019
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WWCI, by Paul Caine
Astronomers in the U.S. and Italy believe they may have detected gravitational waves created when a black hole swallowed a neutron star. If the discovery is confirmed, it would be the first evidence that black holes and neutron stars can pair up to form binary systems.

The apparent detection was made on April 26 by the twin LIGO observatories in the U.S. and the Virgo detector in Italy.

Neutron stars are extremely dense stars formed when massive stars collapse.

"A neutron star is kind of the most extreme star that is possible," said Daniel Holz, a University of Chicago astrophysicist who is part of the LIGO team. "When a star starts collapsing the first stop along the way is a white dwarf and that's when electrons inside the star are pushing against each other and that can hold the star up. But if the star is big enough it will continue to collapse and you'd end up with something called a neutron star. And that's when the neutrons are actually pushing against each other. And as far as we know that is it, that's the densest matter that is possible."

Related:
Department members: Daniel E. Holz
Scientific projects: Laser Interferometer Gravitational-wave Observatory

Astronomers Take First-Ever Picture of a Black Hole
April 11, 2019
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Chicago Tonight (WTTW), by Paul Caine
An international team of astronomers has for the very first time captured an image of one of the most exotic and mysterious objects in the universe: a black hole.

Ever since Einstein's theory of relativity first predicted them, black holes have captured the imagination of the public and scientists alike.

A black hole is an object so dense, literally so massive, that the gravity it generates is so strong that light itself cannot escape and even the fabric of space-time breaks down.

"Black holes are one of those things where the public fascination and the scientific fascination completely align," said Daniel Holz, an astrophysicist at the University of Chicago and part of the LIGO team that in 2016 first detected gravitational waves from the collision of two black holes.

"From a scientific perspective they are also incredibly extreme. The equations are very clean. You end up with this solution. But the solution is so crazy - the idea that there are black holes - that even Einstein said they are probably not real," said Holz.

But real they are and now we have a picture of one.

Carlstrom said that his first reaction on seeing the image of the black hole for the first time was: "Holy Smokes! It really works."

"For the people who have worked in this field for decades it's just disbelief that it is really there," he added.

Related:
Department members: John E. Carlstrom, Daniel E. Holz
Scientific projects: Laser Interferometer Gravitational-wave Observatory, South Pole Telescope

Astronomers capture historic first image of a black hole
April 10, 2019
The first image ever captured of a black hole.
Courtesy of EHT Collaboration
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UChicago News
South Pole Telescope contributes to observations of black hole in distant galaxy

The Event Horizon Telescope - a planet-scale array of eight ground-based radio telescopes forged through international collaboration - was designed to capture images of a black hole. On April 10, in coordinated news conferences across the globe, researchers reveal that they have succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow.

This breakthrough was announced April 10 in a series of six papers published in a special issue of The Astrophysical Journal Letters. The image reveals the black hole at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. This black hole sits 55 million light-years from Earth and has a mass 6.5 billion times that of the sun.

The EHT links telescopes around the globe, including the University of Chicago-run South Pole Telescope, to form an unprecedented Earth-sized "virtual telescope" with unprecedented sensitivity and resolution. The EHT is the result of years of international collaboration, and offers scientists a new way to study the most extreme objects in the universe predicted by Einstein's theory of general relativity.

"The South Pole Telescope's location at the southernmost point of the Earth makes it an important component of the global EHT network," said Prof. John Carlstrom, who directs the telescope. "Although M87 is not visible from the South Pole, it is a crucial player in observing other black holes, such as the massive one at the center of our own galaxy."

Related:
Department members: John E. Carlstrom
Scientific projects: South Pole Telescope

How to use gravitational waves to measure the expansion of the universe
April 2, 2019
Prof. Daniel Holz
University of Chicago News Office, by Louise Lerner
Prof. Daniel Holz discusses a new way to calculate the Hubble constant, a crucial number that measures the expansion rate of the universe and holds answers to questions about the universe's size, age and history.

Related:
Department members: Daniel E. Holz
Scientific projects: Laser Interferometer Gravitational-wave Observatory

Lifetime Achievement Award
March 13, 2019
Wendy L. Freedman, John and Marion Sullivan University Professor in Astronomy and Astrophysics, University of Chicago
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The Chicago Council on Science and Technology
Wendy Freedman is a renowned astronomer who was instrumental in precisely measuring the Hubble constant and determining the age of the universe. Freedman received both her BSc and PhD in astronomy and astrophysics from the University of Toronto. In 1984 she accepted a position as a postdoctoral fellow at the Carnegie Observatories in Pasadena, California. In 1987 Freedman became the first woman to join Carnegie's permanent staff, and in 2003 she became its director. She also initiated the Giant Magellan Telescope project and served as chair of its board of directors from the project's inception in 2003 until 2015. In 2014 she joined the faculty of the University of Chicago as the John and Marion Sullivan University Professor of Astronomy and Astrophysics. Freedman first rose to prominence leading the Hubble Space Telescope Key Project, which began in the mid-1980s and involved an international group of some 30 astronomers. The team used the Hubble telescope to study Cepheid variable stars in order to estimate intergalactic distances and thus determine the expansion rate of the universe.

Related:
Department members: Wendy L. Freedman
Scientific projects: Giant Magellan Telescope

Edward 'Rocky' Kolb to direct Kavli Institute for Cosmological Physics
February 27, 2019
Prof. Rocky Kolb
Photo by Jason Smith
UChicago News
Cosmologist to lead center dedicated to study of origin and evolution of universe

The University of Chicago has named Edward W. 'Rocky' Kolb as director of its Kavli Institute for Cosmological Physics, a leading center dedicated to deepening our understanding of the origin and evolution of the universe and the laws that govern it.

Kolb, the Arthur Holly Compton Distinguished Service Professor in the Department of Astronomy and Astrophysics, succeeds Michael S. Turner as director, effective April 1. Turner, the Bruce V. & Diana M. Rauner Distinguished Service Professor in the Department of Astronomy and Astrophysics, has served in the role since 2010.

"We are thrilled that Rocky Kolb will lead KICP. Kolb, together with current KICP director Michael Turner, helped define a new discipline at the intersection of cosmology, particle physics and astrophysics," said Angela V. Olinto, dean of the Physical Sciences Division. "Kolb's extensive leadership experience will guarantee a brilliant future for KICP."

The institute was created as an interdisciplinary center to bridge astronomy and physics, exploring physics ranging from the subatomic scale to the birth and constitution of the cosmos. It is an international hub for cosmology and has furthered the careers of many young scientists.

At the institute, UChicago researchers tackle questions about the nature of dark energy and dark matter, the first moments of the universe, and nature's highest-energy particles. Members lead some of the most significant international astronomy projects in the field, such as the Dark Energy Survey, an unprecedented survey of distant galaxies to better understand the mysterious force accelerating the expansion of the universe; the South Pole Telescope, which with its third-generation camera will be among the most sensitive instruments observing the cosmic microwave background; and the Giant Magellan Telescope, a giant ground-based telescope under construction in Chile that is expected to produce images that are 10 times sharper than those from the Hubble Space Telescope.

"Rocky Kolb is an eminent cosmologist, known for his contributions to the study of the very early universe," said Kevin Moses, vice president of science programs at the Kavli Foundation. "He has had a distinguished career at the University of Chicago and Fermi National Accelerator Laboratory and is a longtime member of KICP. Rocky will continue the strong tradition of leadership at KICP, paving the way for further understanding of our cosmos."

Kolb is a fellow of the American Academy of Arts and Sciences and the American Physical Society. He has received numerous honors, including the Dannie Heineman Prize for Astrophysics, which he shared with Turner for their work to understand the early universe. Kolb has formerly served as dean of the Physical Sciences Division, chair of the Department of Astronomy and Astrophysics, and director of Fermi National Accelerator Laboratory's Particle Astrophysics Center.

The University established the Center for Cosmological Physics in 2001 with National Science Foundation support. The center was renamed the Kavli Institute for Cosmological Physics in 2004 in honor of Fred Kavli, who through the Kavli Foundation provided $7.5 million to endow the institute and support its programs.

UChicago's Kavli Institute works closely with the other Kavli Institutes in astrophysics at Stanford University, Peking University, Massachusetts Institute of Technology, University of California, Berkeley; and the University of Cambridge.

Related:
Department members: Edward ''Rocky'' W. Kolb, Angela V. Olinto, Michael S. Turner
Scientific projects: Dark Energy Survey, Giant Magellan Telescope

Big Brains podcast: "What Ripples in Space-Time Tell Us About the Universe with Daniel Holz"
January 24, 2019
Prof. Daniel Holz
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UChicago News
UChicago cosmologist discusses discovery of gravitational waves and colliding black holes

All around us in the universe, black holes are smashing into each other with tremendous force. These events are so powerful that they cause ripples in the fabric of space-time - and these ripples, called gravitational waves, travel hundreds of millions of light-years across the universe, eventually passing through the Earth.

Prof. Daniel Holz and fellow scientists at LIGO knew that detecting these waves would take us closer to figuring out many profound mysteries, including the size, age and composition of the universe. They built the most sensitive machine ever constructed, detected the waves and opened up an entirely new window on the universe.

In this time-and-space-bending episode of Big Brains, the UChicago cosmologist talks black holes, testing Einstein's predictions, and the threat of nuclear annihilation.

Related:
Department members: Daniel E. Holz
Scientific projects: Laser Interferometer Gravitational-wave Observatory

After mapping millions of galaxies, Dark Energy Survey finishes data collection
January 15, 2019
UChicago News
For the past six years, Fermi National Accelerator Laboratory has been part of an international effort to create an unprecedented survey of distant galaxies and better understand the nature of dark energy - the mysterious force accelerating the expansion of the universe.

After scanning about a quarter of the southern skies over 800 nights, the Dark Energy Survey finished taking data on Jan. 9. It ends as one of the most sensitive and comprehensive surveys of its kind, recording data from more than 300 million distant galaxies.

Fermilab, an affiliate of the University of Chicago, served as lead laboratory on the survey, which included more than 400 scientists and 26 institutions. The findings created the most accurate dark matter map of the universe ever made, shaping our understanding of the cosmos and its evolution. Other discoveries include the most distant supernova ever detected, a bevy of dwarf satellite galaxies orbiting our Milky Way, and helping to track the first-ever detection of gravitational waves from neutron stars back to its source.

According to Dark Energy Survey Director Rich Kron, a Fermilab scientist and professor at the University of Chicago, those results - and the scientists who made them possible - are where much of the real accomplishment of the Dark Energy Survey lies.

"The first generations of students and postdoctoral researchers on the Dark Energy Survey are now becoming faculty at research institutions and are involved in upcoming sky surveys," Kron said. "The number of publications and people involved are a true testament to this experiment. Helping to launch so many careers has always been part of the plan, and it's been very successful."

Now the job of analyzing that data takes center stage, providing opportunities for new breakthroughs. The survey has already released a full range of papers based on its first year of data, and scientists are now diving into the rich seam of catalogued images from the first several years of data, looking for clues to the nature of dark energy.

The first step in that process, according to Fermilab scientist Josh Frieman, a professor at UChicago and former director of the Dark Energy Survey, is to find the signal in all the noise.

"We're trying to tease out the signal of dark energy against a background of all sorts of non-cosmological stuff that gets imprinted on the data,' Frieman said. "It's a massive ongoing effort from many different people around the world."

Related:
Department members: Joshua A. Frieman, Richard G. Kron
Scientific projects: Dark Energy Survey