Hanna GWave
Hanna Gravitational Wave
Physics and Astronomy Group
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Hanna Gravitational Wave Physics and Astronomy Group

Name: Scalable CI for Early Warning Gravitational Wave Detections
Source: National Science Foundation (OAC-1841480)
Dates: 10/1/2018 - 9/30/2021
Roles: Chad Hanna (PI)
Sponsored Personnel:


The recent multi-messenger detection of of the binary neutron star merger known as GW170817 changed astronomy overnight. The source was detected first in gravitational waves, two seconds later in gamma rays and after 10 hours in optical, ultraviolet, infrared, and much later x-ray and radio. From this single event the world learned that the progenitors of at least some short-hard gamma ray bursts are neutron star mergers, the origin of many elements in the periodic table such as gold and platinum might also be neutron star mergers, gravity and light travel at the same speed, and gravitational waves really could measure the expansion rate of the universe! Despite what was learned, GW170817 left the world with many questions. What object was formed afterward? Another neutron star? A black hole? Why was the gamma ray burst associated with GW170817 unlike anything else that had been observed? Data is required to address these questions - specifically electromagnetic data taken right when the neutron stars merged. It is possible to use gravitational wave data, which measures the neutron star before it merges, to automatically direct robotic observations of telescopes across the world and in space. Doing so requires tremendous cyber-infrastructure which is presently lacking. Using gravitational waves to provide an early warning for robotic telescopes will significantly enhance the scientific utility of LIGO data by enabling multi-messenger astrophysics associated with measuring electromagnetic radiation across the spectrum right as the two neutron stars merge helping to answer what drives some of the brightest objects in the known universe. This project will fortify the streaming data delivery of LIGO by producing sub-second data delivery to a streaming early warning search for neutron star mergers. Substantial monitoring and feedback will be put in place to ensure that the entire system operates without human intervention from the instrument all the way to a public alert within seconds of data taking. The project will capitalize upon existing NSF investments in cyber-infrastructure for real-time gravitational wave analysis, but will augment significantly the layer which handles data delivery and automation, which is presently a bottleneck and failure mode.


1. "Fast evaluation of multidetector consistency for real-time gravitational wave searches." Hanna, Chad, et al. Physical Review D. 101 2 022003 (2020)
2. "The LIGO HET Response (LIGHETR) Project to Discover and Spectroscopically Follow Optical Transients Associated with Neutron Star Mergers." Bustamante Rosell, Maria Jose, et al. Bulletin of the American Physical Society. 65 (2020)
3. "GW190814: Gravitational waves from the coalescence of a 23 solar mass black hole with a 2.6 solar mass compact object." Abbott, Richard, et al. The Astrophysical Journal Letters. 896 2 L44 (2020)
4. "GW190425: Observation of a compact binary coalescence with total mass~ 3.4 M⊙." Abbott, BP, et al. The Astrophysical Journal Letters. 892 1 L3 (2020)
5. "GW190412: Observation of a binary-black-hole coalescence with asymmetric masses." Abbott, R, et al. Physical Review D. 102 4 043015 (2020)
6. "The GstLAL Search Analysis Methods for Compact Binary Mergers in Advanced LIGO's Second and Advanced Virgo's First Observing Runs." Sachdev, Surabhi, et al. arXiv preprint arXiv:1901.08580. (2019)
7. "Sub-threshold Binary Neutron Star Search in Advanced LIGO’s First Observing Run." Magee, Ryan, et al. The Astrophysical Journal Letters. 878 1 L17 (2019)
8. "Low-latency gravitational-wave alerts for multimessenger astronomy during the second Advanced LIGO and virgo observing run." Abbott, Benjamin P, et al. The Astrophysical Journal. 875 2 161 (2019)
9. "Application of a zero-latency whitening filter to compact binary coalescence gravitational-wave searches." Tsukada, Leo, et al. Physical Review D. 97 10 103009 (2018)

1. Chad Hanna "Compact Binaries in Advanced LIGO's Third Observing Run" April APS meeting, American Physical Society, Washington DC (held virtually) April 18, 2020 (Invited)
2. Chad Hanna "Gravitational Wave Astronomy with LIGO and Virgo" Black Holes and Neutron Stars with Gravitational Waves, Yukawa Institute at Kyoto University, Kyoto, Japan October 7, 2019 (Invited)
3. Chad Hanna "Advanced LIGO’s third observing run" FOE 2019, NC State, Raleigh, NC May 21, 2019 (Invited)
4. Chad Hanna "The future of LIGO/Virgo and Electromagnetic follow-ups" FOE 2019, NC State, Raleigh, NC May 21, 2019 (Invited)
5. Chad Hanna "Windows on the Universe" Perimeter Institute, Waterloo Ontario April 3, 2019 (Invited)