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October 2017



CIERA’s Shane Larson Joins U.S. NASA LISA Study Team

CIERA Associate Director and Research Professor Shane Larson has been named to the NASA LISA Study Team. LISA, the "Laser Interferometer Space Antenna," is a space-based detector that will be jointly flown by NASA and the European Space Agency near the end of the next decade.

The NASA LISA Study Team was established by NASA HQ in October 2017 to assist the U.S. community in preparing for the 2020 astrophysics Decadal Survey and provide input to the Study Office and NASA HQ on the LISA mission. It consists of independent U.S. scientists with expertise in gravitational wave technologies, signal analysis, and astrophysics.


Graduate Student Katie Breivik Wins Blue Apple Prize at MRM

The 27th Midwest Relativity Meeting was held October 12-14, 2017, at the University of Michigan in Ann Arbor. This meeting brings together researchers from across the Midwest and beyond to discuss General Relativity and a broad range of topics in gravitational physics.

Astronomy graduate student Katie Breivik won the Blue Apple Prize for the best student talk, out of nearly 40 presentations. Her talk was titled, “Revealing the Milky Way's black hole population with Gaia.”

Congratulations, Katie!


CIERA Astronomers Help Detect Colliding Neutron Stars for the First Time

On October 16, 2017, scientists announced the first-ever observation of a binary neutron star inspiral and merger—this astronomical event will provide a powerful new way to understand the lives of stars and how they die and join the galactic graveyard.

Vicky Kalogera with fellow NSF panelist David Reitze (LIGO/Caltech)

Vicky Kalogera, CIERA Director and Daniel I. Linzer Distinguished University Professor in the Weinberg College of Arts and Sciences, served as lead astrophysicist on the panel at the National Science Foundation’s (NSF) press conference announcing the discovery.

Anticipated by the Laser Interferometer Gravitational-Wave Observatory (LIGO) for more than 20 years, this merger represents the first joint detection of an astronomical event using two astronomical observing techniques: gravitational waves and electromagnetic radiation. Together these approaches are known as "multi-messenger astronomy". Gravitational waves were the subject of 2017's Nobel Prize in Physics, and multi-messenger astronomy was named one of the NSF's 10 Big Ideas for future scientific investment. Northwestern is currently one of the few universities in the world with expertise on both sides of this cutting-edge field.

Watch the full press conference, featuring Vicky Kalogera.

Learn more from CIERA researcher interviews at Northwestern's LIGO Media Gallery.
Go "Behind the Scenes" as Vicky Kalogera prepares to share this groundbreaking news at the NSF Press Conference.
Read the Northwestern News story for more details on this exciting discovery.
View the Northwestern Special Feature, for videos, podcast, and featuring CIERA astronomers involved in the discovery!
Listen to Vicky Kalogera discuss the merger on Science Friday:

Join us on November 28, 2017 at a Round Table discussion for an insider's view of the discovery.

These collected news stories contain quotes and interviews from various CIERA/Northwestern researchers involved in the multi-messenger detection.


2017 Nobel Prize in Physics Awarded to Gravitational-wave Scientists Barish, Thorne, and Weiss

Barry Barish, Kip Thorne and Rai (Rainer) Weiss received the 2017 Nobel Prize in Physics October 3rd for decisive contributions to the LIGO detector and the observation of gravitational waves. Thorne and Weiss are previous CIERA Annual Public Lecturers.

“I was so much hoping for this wonderful news,” said Vicky Kalogera, gravitational-wave astrophysicist and Director of CIERA at Northwestern University, who contributed to the historic detections of gravitational waves. “My Northwestern colleagues and I warmly congratulate Rai, Kip and Barry on this recognition. The discovery of black-hole mergers and the detection of gravitational waves never would have happened without these creative scientists.”

Gravitational waves, ripples in the fabric of spacetime, were first predicted by Albert Einstein in 1916 and are a new way of observing the universe. The Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration has detected gravitational waves four times – first, on Sept. 14, 2015, and most recently, on Aug. 14, 2017. All four signals detected so far were created by colliding black holes.

Moving forward, astronomers are working on methods for combining gravitational wave data and electromagnetic data to study cosmic sources. The National Science Foundation named this new technique, called multi-messenger astronomy, one of the top six ideas to pursue in the future. Multi-messenger astronomy holds the answers to untold astronomical questions, including how the universe was formed.

“Rai, Kip and Barry launched the LIGO project decades ago and worked very hard to confirm Einstein’s theory,” said Kalogera, the Linzer Distinguished University Professor in Physics and Astronomy in the Weinberg College of Arts and Sciences. “I am so proud to have had the opportunity to learn from them since my years as a young researcher. Rai and Kip especially were influential in my decision to join the LIGO Scientific Collaboration at a time when most ‘traditional’ astronomers were advising me against it. I have grown through their advice and support and will always be grateful for what they have achieved for science and the younger generation of scientists.”

A Ligo Scientific Collaboration (LSC) member for more than 15 years, Kalogera is LSC’s most senior astrophysicist. She leads Northwestern’s LSC group, which includes Shane L. Larson, CIERA associate director and a research associate professor of physics and astronomy at Northwestern, and Selim Shahriar, professor of electrical engineering and computer science at Northwestern’s McCormick School of Engineering. Larson and Shahriar also have been mentored over the years by Weiss or Thorne. Eleven postdoctoral fellows and graduate and undergraduate students also are members of the Northwestern group.

Learn more about the first gravitational-wave detections and Northwestern’s role in the discoveries:


September 2017



CIERA Researchers Contribute to Record-setting Gravitational Wave Detection

The LIGO Scientific Collaboration (LSC) and the Virgo collaboration announced today (Sept. 27) the first joint detection, made on August 14, of gravitational waves with both LIGO and Virgo detectors. It is the fourth announced detection of a binary black hole system and the first significant gravitational-wave signal recorded by the Virgo detector, located near Pisa, Italy.

“This discovery is the first one made with three detectors -- two in the U.S. and a third across the ocean in Italy. As such, it is especially significant. This first-ever triple detection allows us to localize where the event occurred, so our research partners in observational astronomy can more accurately scan the sky to look for electromagnetic counterparts. This type of multi-messenger information will be key for solving the great cosmic puzzles. All pieces are needed,” says CIERA’s Director, Professor Vicky Kalogera.

Shane Larson, CIERA’s Associate Director, explains, “Gravitational wave astronomy isn't like telescope astronomy. We've always known that our ability to map sources on the sky will get better as more detectors join the network, and Virgo has shown us what a difference it makes with a bang!"

Read LIGO’s news release. Continue to Shane Larson’s blog post about the triple event.

LIGO is funded by the NSF, and operated by Caltech and MIT, which conceived and built the project. Financial support for the Advanced LIGO project was led by NSF with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council) making significant commitments and contributions to the project. More than 1,200 scientists from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration. Additional partners are listed at The Virgo collaboration consists of more than 280 physicists and engineers belonging to 20 different European research groups: six from Centre National de la Recherche Scientifique (CNRS) in France; eight from the Istituto Nazionale di Fisica Nucleare (INFN) in Italy; two in The Netherlands with Nikhef; the MTA Wigner RCP in Hungary; the POLGRAW group in Poland; Spain with the University of Valencia; and EGO, the laboratory hosting the Virgo detector near Pisa in Italy.

Image Credit: LIGO/Virgo/NASA/Leo Singer/Axel Mellinger


Unique Supernova Revealed by CIERA Postdoc Giacomo Terreran

In a new study published in Nature Astronomy, CIERA postdoctoral associate Giacomo Terreran discusses a highly unusual supernova. The object, called OGLE14-073, is more luminous, richer in hydrogen, slower to evolve, 10 times more energetic, and ejected more material than typical objects in its class.

Interviewed by Marco Galliani for Media INAF, Terreran explains, “OGLE14-073 is a unique object and we are still investigating possible exploding scenarios. When it was classified, OGLE14-073 appeared just like a boring type II supernova as hundreds are identified each year. However, it soon revealed its extraordinary character. In the future, with the advent of the next generation of telescopes, many more objects similar to OGLE14-073 will be likely discovered. We hope to be able to find them soon after explosion, with more targeted follow-up campaigns, with the aim to be able to understand what is the mechanism responsible to make explode such massive stars with such a high energy.”

Read Hydrogen-rich supernovae beyond the neutrino-driven core-collapse paradigm, in Nature Astronomy.


CIERA Postdoc Fabio Antonini Finds that Many LIGO Sources Arise from Mergers at the Centers of Galaxies

The first direct observation of merging black holes by Advanced LIGO opened a new window to our Universe. The new set of data from these detectors will provide important clues about the properties and formation of neutron stars and black holes and about the environment in which they form. But a better understanding of the processes that lead to the merger of black holes is needed in order to make sense of the large data set anticipated in the coming years.

Massive stars are very social: they are often found accompanied by one or more close friends. It is not surprising therefore that the evolution of massive binary stars in the outskirts of galaxies has been suggested as the main channel for the formation of the merging black holes observed by LIGO. Massive stars are also commonly found at the center of galaxies, including the Milky Way, and dynamical processes in such environments could also cause black holes to merge.

Unlike the stellar binaries in the field, the binaries in the galactic center feel strong gravitational perturbations from their neighboring stars and the super massive black holes sitting at the center. CIERA postdoctoral fellow Fabio Antonini and his colleague at the Canadian Institute for Theoretical Astrophysics, Cristobal Petrovich, have modeled the dynamics of these binaries and realized that massive stars will quite often undergo a chaotic dance that ends with a merger by gravitational wave radiation. Surprisingly, this chaotic dance is effective enough that it can explain a significant fraction of the LIGO observations. This suggests that the galactic nuclei are privileged places in the galaxies for stellar mass black holes to merge.

Read the blog post by Cristobal Petrovich about the project.
Read the paper, Greatly Enhanced Merger Rates of Compact-object Binaries in Non-spherical Nuclear Star Clusters.


Graduate Student Eve Chase Wins Best Poster Award at LSC-Virgo Meeting

At the LSC-Virgo September Meeting near Geneva, Switzerland, graduate student Eve Chase won the best poster award in the Data Analysis/Theory category.

The meeting took place August 28 - September 1, 2017 at CERN, the European Organization for Nuclear Research. The LIGO Scientific Collaboration (LSC) is a collaboration of international physics institutes and research groups dedicated to the search for gravitational waves. Virgo is an interferometer gravitational wave detector in Pisa, Italy.

Eve is a second-year astronomy graduate student who is part of Vicky Kalogera’s group. Eve studies computational and data analysis techniques related to gravitational wave astronomy. Her poster, titled "Gravitational-Wave Localization in the LSST Era,” focused on using the Large Synoptic Survey Telescope to search for electromagnetic counterparts to gravitational waves. Eve took home 150 Swiss Francs as her prize.

Co-authors on Eve’s project include Sam Imperato and Monica Rizzo (along with Chris Pankow, Scott Coughlin and Vicky Kalogera, all from Northwestern). Sam is a high school student who contributed heavily to tracking improvements to GW source localization as additional detectors are commissioned. Monica Rizzo is a Research Experience for Undergraduates (REU) student from the Rochester Institute of Technology. She spent her summer modeling expected light curves from gravitational-wave counterparts, such as kilonovae.

Congratulations, Eve!


“Three Cosmic Chirps and Counting” by CIERA Director Vicky Kalogera

The September 2017 issue of Sky & Telescope magazine features an article by Vicky Kalogera which gives her personal and professional account of the first gravitational wave events detected by LIGO. In the article, Prof.Kalogera describes the science behind the detections, their significance and promise, as well as the excitement in the astronomy community as these phenomenal occurrences unfolded.

Access the September 2017 issue.


CIERA Welcomes New Faculty Members: Wen-Fai Fong & Sasha Tchekhovskoy

Northwestern University is in the midst of an astrophysics faculty expansion plan. With last year’s arrival of Raffaella Margutti, an expert in 'transient phenomena' such as supernovae and gamma ray bursts, Northwestern became one of the very few universities in the nation with both a LIGO research group and a transient astronomy team.

This fall, we are excited to announce two new astrophysics faculty additions at CIERA: Wen-fai Fong and Sasha Tchekhovskoy. Wen-fai's research focuses on mergers of compact objects and their environments; she chases the elusive electromagnetic counterparts to gravitational-wave sources. She will be a Hubble Postdoctoral Fellow for her first year at Northwestern, before moving into her faculty role.

A former NASA Einstein Fellow, Sasha will start as an assistant professor this fall. His interests include high-energy astrophysics processes powered by compact objects, black holes, and neutron stars which he simulates using high-performance computing.

Welcome, Wen-fai and Sasha!


Announcing CIERA Director of Operations Kari Frank & Associate Director Shane Larson

We are pleased to announce our new Director of Operations, Dr. Kari Frank. Kari holds a PhD in Physics from Purdue, and is formerly a Research Associate at Penn State. Kari’s focus is X-ray observations of galaxy clusters and supernova remnants. In addition to her research, Kari has devoted time at both Purdue and Penn State to help improve the careers of graduate students and postdocs.

Welcome, Kari!

With Kari’s arrival, we wish farewell to John Everett, who served extremely capably for the past 5 years as Assistant Director and then Director of Operations for CIERA. John has taken an exciting professional opportunity in the Denver Public Schools and has moved west to pursue this, as well as to be closer to his family. We thank John and wish him all the best!

As of September 1st, Prof. Shane Larson will take on the new role of Associate Director of CIERA as half-time of his full-time position at Northwestern (transitioning from a joint position between Northwestern and the Adler Planetarium). As Associate Director (part-time), Shane will take on CIERA's growing responsibilities in the areas of public outreach, science communication, and development efforts, engaging with Northwestern Alumni and CIERA Friends.

Past News and Announcements