SAGUARO: Time-domain Infrastructure for the Fourth Gravitational-wave Observing Run and Beyond

Griffin Hosseinzadeh, Kerry Paterson, Jillian C. Rastinejad, Manisha Shrestha, Philip N. Daly, Michael J. Lundquist, David J. Sand, Wen Fai Fong, K. Azalee Bostroem, Saarah Hall, Samuel D. Wyatt, Alex R. Gibbs, Eric Christensen, William Lindstrom, Jonathan Nation, Joseph Chatelain, Curtis McCully

Research output: Contribution to journalArticlepeer-review


We present upgraded infrastructure for Searches After Gravitational waves Using ARizona Observatories (SAGUARO) during LIGO, Virgo, and KAGRA’s fourth gravitational-wave (GW) observing run (O4). These upgrades implement many of the lessons we learned after a comprehensive analysis of potential electromagnetic counterparts to the GWs discovered during the previous observing run. We have developed a new web-based target and observation manager (TOM) that allows us to coordinate sky surveys, vet potential counterparts, and trigger follow-up observations from one centralized portal. The TOM includes software that aggregates all publicly available information on the light curves and possible host galaxies of targets, allowing us to rule out potential contaminants like active galactic nuclei, variable stars, solar system objects, and preexisting supernovae, as well as to assess the viability of any plausible counterparts. We have also upgraded our image-subtraction pipeline by assembling deeper reference images and training a new neural-network-based real-bogus classifier. These infrastructure upgrades will aid coordination by enabling the prompt reporting of observations, discoveries, and analysis to the GW follow-up community, and put SAGUARO in an advantageous position to discover kilonovae in the remainder of O4 and beyond. Many elements of our open-source software stack have broad utility beyond multimessenger astronomy, and will be particularly relevant in the “big data” era of transient discoveries by the Vera C. Rubin Observatory.

Original languageEnglish (US)
Article number35
JournalAstrophysical Journal
Issue number1
StatePublished - Mar 1 2024

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'SAGUARO: Time-domain Infrastructure for the Fourth Gravitational-wave Observing Run and Beyond'. Together they form a unique fingerprint.

Cite this