Chiara Mingarelli, Ph.D. 
Assistant Professor of Physics | University of Connecticut
Storrs, CT, UNITED STATES
Chiara Mingarelli is a gravitational-wave astrophysicist, researching how supermassive black holes in the centers of massive galaxies merge.
Biography
Prof. Chiara M. F. Mingarelli is a gravitational-wave astrophysicist based at the University of Connecticut, with a joint appointment at Flatiron Institute's Center for Computational Astrophysics, where she is an Associate Research Scientist. Previously, Mingarelli was a Marie Curie International Outgoing Fellow at the California Institute of Technology, and at the Max Planck Institute for Radio Astronomy, and a Flatiron Fellow.
Mingarelli received her Ph.D from the University of Birmingham (UK) in 2014, where she worked with Prof. Alberto Vecchio. Her core research is focused on using Pulsar Timing Arrays to detect low-frequency gravitational waves, with forays into electromagnetic counterparts to gravitational-wave events, such as fast radio bursts.
Mingarelli has accumulated over $1M in grants and prizes over her career from the NSF, the ERC, and Amazon. Her honors and awards include APS "Woman Physicist of the Month" for November 2016, her thesis was published in the Springer Thesis Series (2015), and grants from the Royal Astronomical Society, the UK Institute of Physics for both research and outreach, and the National Science Foundation. She has written an invited guest article for Scientific American, contributes to Amy Poehler’s Smart Girls, and regularly appears on the Science Channel's "How the Universe Works."
Areas of Expertise (4)
Astrophysics
Pulsars
Gravitational Waves
Black Holes
Education (3)
University of Birmingham: Ph.D., Gravitational Wave Astrophysics with Pulsar Timing Arrays 2014
Universita' di Bologna: M.Sc., Astrophysics and Cosmology 2009
Carleton University: B.Sc., Double Honours - Mathematics and Physics 2006
Affiliations (7)
- American Astronomical Society
- American Physical Society
- NANOGrav
- European Pulsar Timing Array
- International Pulsar Timing Array
- Fellow of the Royal Astronomical Society (FRAS)
- Associate Member of the Institute of Physics (AmIoP)
Accomplishments (6)
2023 AAS High Energy Astrophysics Division (HEAD) Early Career Prize (professional)
2023-01-31
The American Astronomical Society (AAS), a major international organization of professional astronomers, recognizes outstanding achievements in research and education.
Amazon Web Services ML Award
2018
Marie Curie International Outgoing Fellowship
2014 - 2017
Marie Curie Actions “Communicating Science” Prize
2017
American Physical Society
2016
Springer Thesis Award
2015
Links (3)
Media
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Media Appearances (10)
Colliding Supermassive Black Holes Discovered in Nearby Galaxy
Scientific American online
2023-01-18
“This pair was really exciting because they’re so close to each other and they’re so nearby,” says Chiara Mingarelli, one of the study’s authors and an astrophysicist at the Flatiron Institute in New York City and the University of Connecticut. Separated by only some 750 light-years, or 230 parsecs, they are the closest pair of black holes that scientists have been able to confirm by measuring multiple wavelengths of light. These black holes’ proximity to Earth and each other may provide a unique opportunity for fundamental studies of giant black hole mergers, as well as one of their most elusive by-products: ripples in spacetime called gravitational waves.
Chiara Mingarelli on Searching for Black Holes with Pulsars
Sean Carroll's Mindscape online
2022-09-26
The detection of gravitational waves from inspiraling black holes by the LIGO and Virgo collaborations was rightly celebrated as a landmark achievement in physics and astronomy. But ultra-precise ground-based observatories aren’t the only way to detect gravitational waves; we can also search for their imprints on the timing of signals from pulsars scattered throughout our galaxy. Chiara Mingarelli is a member of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration, which uses pulsar timing to study the universe using gravitational waves.
Image of Black Hole at Center of Milky Way Galaxy Is Unveiled
Wall Street Journal online
2022-05-12
The image, released Thursday during simultaneous news conferences hosted by various institutions in seven countries, reveals the black hole, named Sagittarius A*, as a dark center silhouetted against a bright orange-yellow ring. Black holes by their very nature are unseeable, but their boundaries cast a shadow against the bright backdrop of hot gas and dust that encircles them. That shadow is what’s visible to certain telescopes on Earth. “I am in awe because that’s our supermassive black hole,” said University of Connecticut physicist Dr. Chiara Mingarelli, who wasn’t involved in producing the image. “It feels very personal to see it for the first time, to have that undeniable image of it.”
Inspiring Women in Science
Nature online
2022-01-26
Chiara Mingarelli is a gravitational-wave astrophysicist, looking to understand how supermassive black holes in the centers of massive galaxies merge. She does this by predicting their nanohertz gravitational-wave signatures, which will soon be detected by Pulsar Timing Array experiments. With pulsar timing data, she looks for both individual supermassive black holes in binary systems, and for the gravitational-wave background which should be generated by their cosmic merger history.
When Galaxies Collide: UConn Astrophysicist Investigating Supermassive Black Hole Mergers
UConn Today online
2021-10-25
Scientists have not yet been able to prove the existence of these supermassive black hole mergers, or binaries. Chiara Mingarelli, assistant professor of physics, was the lead researcher on a $650,000 Collaborative Research Grant from the National Science Foundation, half of which is earmarked for UConn, to conduct an experiment to prove the existence of supermassive black hole binaries.
A Signal From Beyond
UConn Today online
2021-02-15
UConn astrophysicist Chiara Mingarelli is part of a team of researchers who recently published data on a hint of a signal that sent ripples of excitement through the physics community. These monumental findings are the culmination of twelve and a half years of data gathered from NANOGrav — a network of pulsars across the galaxy — all in the hopes of detecting gravitational waves.
Arecibo’s Collapse Sends Dire Warning to Other Aging Observatories
Scientific American print
2020-12-11
Chiara Mingarelli, a gravitational-wave astrophysicist at the University of Connecticut, is part of the NANOGrav project, which looks for nanohertz-frequency gravitational waves via subtle variations they should induce upon the arrival times of metronomelike radio pulses from large numbers of pulsars scattered across the heavens. Such waves—which have yet to be conclusively seen via this “pulsar timing array” method—are thought to come from merging pairs of supermassive black holes. Arecibo had been monitoring half of NANOGrav’s targeted pulsars. “We can still do [pulsar timing]. It’s just that Arecibo was really good at it,” Mingarelli says. “We lost our star quarterback.”
Astronomers see first light flare from two distant black holes colliding
The Verge online
2020-06-25
When neutron stars collide, the mergers can sometimes be picked up by observatories that measure their light, even though the objects are really faint. When black holes collide, it’s not something we can see — until perhaps now. “It’s a weird and wonderful event, and in fact we don’t know how rare they are,” Chiara Mingarelli, an assistant professor at the University of Connecticut studying gravitational waves, who was not involved in the study, tells The Verge.
The plan to use pulsars as galactic-scale gravitational wave detectors for supermassive collisions
New Atlas online
2017-11-14
These pulsar timing arrays are based on the same principle as LIGO and Virgo. Essentially, if enough is known about each pulsar, then their signals can be predicted incredibly precisely, so if those signals are delayed by even the tiniest fraction of time, then that could indicate that a gravitational wave has rolled through. Importantly, this method could be more tuned towards lower frequency waves. "A difference between when the pulsar signals should arrive, and when they do arrive, can signal a gravitational wave," says Chiara Mingarelli, lead author of the new study. "And since the pulsars we study are about 3,000 light-years away, they act as a galactic-scale gravitational-wave detector."
Gravitational Waves Detected, Verifying Part of Albert Einstein’s Theory of General Relativity
Wall Street Journal print
2016-02-18
Gravitational waves from the merger of black holes, neutron stars or other massive objects would produce a chirp much like the increasing pitch of a slide whistle, the researchers said. Those likely produced by supernovae or gamma ray bursts produce telltale pops and crackles. The oldest—relics of the Big Bang—simply sizzle. “Not only can we explore the universe with neutrinos and cosmic rays, see it with light across a huge range of wavelengths, but we can now hear it too with gravitational waves,” said Caltech physicist Chiara M. F. Mingarelli, who studies them. “Imagine hearing the universe for the first time.”
Articles (7)
UGC 4211: A Confirmed Dual Active Galactic Nucleus in the Local Universe at 230 pc Nuclear Separation
The Astrophysical Journal LettersMichael J. Koss et al
2023-01-10
We present multiwavelength high-spatial resolution (∼0farcs1, 70 pc) observations of UGC 4211 at z = 0.03474, a late-stage major galaxy merger at the closest nuclear separation yet found in near-IR imaging (0farcs32, ∼230 pc projected separation). Using Hubble Space Telescope/Space Telescope Imaging Spectrograph, Very Large Telescope/MUSE+AO, Keck/OSIRIS+AO spectroscopy, and the Atacama Large Millimeter/submillimeter Array (ALMA) observations, we show that the spatial distribution, optical and near-infrared emission lines, and millimeter continuum emission are all consistent with both nuclei being powered by accreting supermassive black holes (SMBHs). Our data, combined with common black hole mass prescriptions, suggest that both SMBHs have similar masses, $\mathrm{log}\left({M}_{\mathrm{BH}}/{M}_{\odot }\right)$ ∼ 8.1 (south) and $\mathrm{log}\left({M}_{\mathrm{BH}}/{M}_{\odot }\right)$ ∼ 8.3 (north), respectively. The projected separation of 230 pc (∼6× the black hole sphere of influence) represents the closest-separation dual active galactic nuclei (AGN) studied to date with multiwavelength resolved spectroscopy and shows the potential of nuclear (
Seeing the gravitational wave universe
ScienceChiara M. F. Mingarelli and J. Andrew Casey-Clyde
2022-11-10
Gravitational waves are ripples in the fabric of spacetime that are caused by events such as the merging of black holes. In principle, many types of events occur that could create gravitational waves with frequencies ranging from as high as a few kilohertz to as low as a few nanohertz. Sources of gravitational waves in the nanohertz frequency range include cosmic strings, quantum fluctuations from the early Universe, and, notably, supermassive black hole binaries (SMBHBs). Some gravitational wave sources are so numerous that they are all expected to contribute to a gravitational wave background (GWB). This GWB has been the target of pulsar timing arrays (PTAs) for decades.
A Quasar-based Supermassive Black Hole Binary Population Model: Implications for the Gravitational Wave Background
The Astrophysical Journal2022 The nanohertz gravitational wave background (GWB) is believed to be dominated by GW emission from supermassive black hole binaries (SMBHBs). Observations of several dual-active galactic nuclei (AGN) strongly suggest a link between AGN and SMBHBs, given that these dual-AGN systems will eventually form bound binary pairs. Here we develop an exploratory SMBHB population model based on empirically constrained quasar populations, allowing us to decompose the GWB amplitude into an underlying distribution of SMBH masses, SMBHB number density, and volume enclosing the GWB. Our approach also allows us to self-consistently predict the number of local SMBHB systems from the GWB amplitude. Interestingly, we find the local number density of SMBHBs implied by the common-process signal in the NANOGrav 12.5-yr data set to be roughly five times larger than previously predicted by other models. We also find that at most ∼25% of SMBHBs can be associated with quasars. Furthermore, our quasar-based approach predicts ≳95% of the GWB signal comes from z ≲ 2.5, and that SMBHBs contributing to the GWB have masses ≳108 M⊙. We also explore how different empirical galaxy–black hole scaling relations affect the local number density of GW sources, and find that relations predicting more massive black holes decrease the local number density of SMBHBs. Overall, our results point to the important role that a measurement of the GWB will play in directly constraining the cosmic population of SMBHBs, as well as their connections to quasars and galaxy mergers.
Multimessenger pulsar timing array constraints on supermassive black hole binaries traced by periodic light curves
The Astrophysical Journal2021 Supermassive black hole binary systems (SMBHBs) emitting gravitational waves may be traced by periodic light curves. We assembled a catalog of 149 such periodic light curves, and using their masses, distances, and periods, predicted the gravitational-wave strain and detectability of each binary candidate using all-sky detection maps. We found that the International Pulsar Timing Array (IPTA) provides almost uniform sky coverage -- a unique ability of the IPTA -- and by 2025 will improve NANOGrav's current minimum detectable strain by a factor of 6, and its volume by a factor of 216. Moreover, IPTA will reach detection sensitivities for three candidates by 2025, and 13 by the end of the decade, enabling us to constrain the underlying empirical relations used to estimate SMBH masses. We find that we can in fact already constrain the mass of a binary in Mrk 504 to M
Understanding Ωgw(f) in Gravitational Wave Experiments
arXiv preprint2019 In this paper we provide a comprehensive derivation of the energy density in the stochastic gravitational-wave background Ωgw(f), and show how this quantity is measured in ground-based detectors such as Laser Interferometer Gravitational-Wave Observatory (LIGO), space-based Laser Interferometer Space Antenna (LISA), and Pulsar Timing Arrays. By definition Ωgw(f)∝Sh(f) -- the power spectral density (PSD) of the Fourier modes of the gravitational-wave background. However, this is often confused with the PSD of the strain signal, which we call Sgw(f), and is a detector-dependent quantity. This has led to confusing definitions of Ωgw(f) in the literature which differ by factors of up to 5 when written in a detector-dependent way. In addition to clarifying this confusion, formulas presented in this paper facilitate easy comparison of results from different detector groups, and how to convert from one measure of the strength of the background (or an upper limit) to another. Our codes are public and on GitHub.
Probing supermassive black hole binaries with pulsar timing
Nature Astronomy2019-01-08
Supermassive black hole (SMBH) mergers are the strongest sources of gravitational-waves (GWs) in the Universe. SMBH mergers are expected to follow galaxy mergers, since likely all massive galaxies host central SMBHs (see, for example, ref. 1). Briefly, the black holes fall to the centre of the newly formed galaxy through dynamical friction and form a binary. This binary should harden by ejecting stars crossing its orbit — a process called stellar hardening. When the binary is separated by a centiparsec to a milliparsec, GWs drive the binary to merge.
Searching for the Gravitational Waves LIGO Can't Hear
Scientific American2016-02-24
The direct detection of gravitational waves by the LIGO Scientific Collaboration has opened a new window of observation on the universe. We can now explore the universe with light across the entire electromagnetic spectrum; with cosmic rays and neutrinos; and, as of last September, with gravitational waves as well. Like light, however, gravitational waves span a broad range of frequencies, and just as you cannot use an infrared telescope to observe ultraviolet light or X-rays, you cannot use LIGO to look for every kind of gravitational wave. LIGO’s detectors, with arms four km. long, saw (or rather, heard) waves generated by two merging black holes, each approximately 30 times as massive as the Sun. But for the very low frequency gravitational waves created by the merger of the million- to billion-solar-mass black holes at the centers of most galaxies, you need a detector as big as the Milky Way.
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