Maya Fishbach

NASA Einstein Fellow · CIERA · maya.fishbach@northwestern.edu

I am a gravitational-wave astronomer, currently working at CIERA, Northwestern University, and funded by the NASA Hubble Fellowship Program. I am a member of the LIGO Scientific Collaboration — see my Humans of LIGO profile! Previously, I was an NSF Graduate Research Fellow at the University of Chicago, where I completed my PhD under the supervision of Daniel Holz.


Research

How are black holes made?

How are black holes and neutron stars made, and how do they get into binaries?

LIGO and Virgo have revealed a previously-unobserved population of black holes and neutron stars that collide into one another, emitting a burst of energy in the form of gravitational-waves. Meanwhile, the origin of these systems remains an open question. Several formation scenarios have been proposed, from primordial black holes that make up a fraction of the dark matter (“primordial”), to the ends states of binary stellar evolution in the galactic field (”isolated”), to stellar remnants that form binaries through dynamical interactions in dense environments (“dynamical”), with each category consisting of many proposed variations. In my research, I study the population properties of black holes and neutron stars observed in gravitational-waves, in order to learn about the formation history of these systems.

I have pointed out several powerful features in the distribution of spins, masses, mass ratios, and redshifts of LIGO/Virgo's observations that can be used to probe whether LIGO's black holes are made from smaller black holes, LIGO's missing big black holes and the connection to pair-instability supernovae, the redshift evolution of the merger rate, whether black holes are picky about their partners, and the existence of a mass gap between neutron stars and black holes. My research has implications for the physics of massive stars, binary interactions, and nuclear reaction rates. As we observe more and more black holes and neutron stars, we can precisely resolve features in the population and push our theoretical understanding. We analyzed the population properties of LIGO/Virgo's first 10 binary black holes in this LIGO/Virgo Collaboration paper. Recently I led the population analysis on the ~50 events in the LIGO/Virgo's second gravitational-wave transient catalog; check out our results in this paper.

Where are black holes made?

Where are binary black holes and neutron stars made, and how do these systems co-evolve with their environments?

In order to understand the history of black holes and neutron stars in merging binaries, we must understand where and when they formed. During my PhD, I carried out the first measurement of the evolution of the black hole merger rate as a function of redshift, or cosmic time. By including information from the unresolved stochastic background, we can even constrain the peak merger rate. Contextualizing black holes and neutron stars in cosmic time is a first step towards probing the coevolution of these binaries with the global population of stars, galaxies, and the chemical composition of the universe. We can learn even more about the history of gravitational-wave sources by identifying and characterizing their host galaxies.

How big is the universe?

What can gravitational-wave sources teach us about the size and age of the universe, and the nature of gravity?

The luminosity distance to a compact binary merger is directly encoded in its gravitational-wave signal, earning these systems the name “standard sirens.” This feature makes compact binary mergers extremely powerful probes of the size of the universe and the nature of gravity. I have developed analyses to measure the expansion rate of the universe –the Hubble parameter– by combining gravitational-wave measurements of distance with redshifts supplied either by electromagnetic counterparts, a catalog of galaxies, or the redshifted pair-instability feature in the black hole mass spectrum. Standard sirens can also be used to probe the nature of gravity itself; for example, by measuring the number of spacetime dimensions or the running of the Planck mass. For a recent overview of standard siren cosmology, check out the review that Daniel Holz and I wrote for the Matters of Gravity newsletter.


Curriculum Vitae

Download my CV (updated April 2021)


Publications

Check out my publications on ADS


Press

My research has been featured in Quanta Magazine, Science Magazine, Nature News, Symmtery Magazine, Astrobites, AAS Nova, APS News, University of Chicago News, the Daily Beast, Science News, and Sky & Telescope. Check out some links below!

Growing Inventory of Black Holes Offers a Radical Probe of the Cosmos by Thomas Lewton for Quanta Magazine, February 2021

Big Black Holes Dominate New Gravitational-Wave Catalog by Camille Carlisle for Sky & Telescope, November 2020

What 50 gravitational-wave events reveal about the Universe by Davide Castelvecchi for Nature.com, October 2020

The universe teems with weird black holes, gravitational wave hunters find by Adrian Cho for Science Magazine, October 2020

Going Deep into Black Holes by Sophia Chen for APS News, June 2020

Merger Partners? Maybe. by Tarini Konchady for AAS Nova, April 2020

What Next for Gravitational Wave Detection? by Sophia Chen for APS News, June 2019

Gravitational waves could soon provide measure of universe’s expansion by Louise Lerner for UChicago News, October 2018

Gravitational waves provide dose of reality about extra dimensions by Louise Lerner for UChicago News, September 2018

Black Hole Mergers Through Cosmic Time by Kerry Hensley for AAS Nova, September 2018

Are We Closer to Finding a Fifth Dimension? by Matthew R. Francis for The Daily Beast, February 2018

An Answer to LIGO’s Low-Mass Black Hole Woes by Thankful Cromartie for Astrobites, September 2017

Are LIGO’s Black Holes Made From Smaller Black Holes? by Susanna Kohler for AAS Nova, May 2017

Spin may reveal black hole history by Emily Conover for Science News, January 2017


Contact

The best way to reach me is by e-mail: maya.fishbach@northwestern.edu

For more information about LIGO and gravitational-waves, check out: www.ligo.org

For more information about astrophysics research at Northwestern, check out: ciera.northwestern.edu