GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"19548 results found.
- GRB 190511A: Enhanced Swift-XRT position
- LIGO/Virgo S190510g : Xinglong-60cm upper limit of the GRAWITA REM's OT
- LIGO/Virgo S190510g: Unconfirmed OT in PGC 094244
- LIGO/Virgo S190510g: Dabancheng/HMT Follow-Up Observations
- LIGO/Virgo S190510g: Xinglong/Schmidt Follow-Up Observations
- LIGO/Virgo S190510g: Pierre Auger Observatory follow-up
- GRB 190511A: Swift detection of a burst
- LIGO/Virgo S190510g: SOAR/Goodman follow-up observations
- LIGO/Virgo S190510g: CNEOST Follow-Up Observations
- LIGO/Virgo S190510g: J-GEM optical/NIR follow-up observations
- LIGO/Virgo S190510g: Lick/KAIT Follow-Up Observations
- LIGO/Virgo S190510g: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190510g: Swift/BAT Counterpart Search
- LIGO/Virgo S190510g: HSC Y-band follow-up observation
- LIGO/Virgo S190510g: ANTARES neutrino search
- LIGO/Virgo S190510g: HAWC follow-up
- LIGO/Virgo S190426c: Archival VLASS Observations of ZTF19aassfws 14 days prior to Merger
- GRB 190508A: GOTO optical search - no counterparts
- GRB 190508B: Fermi GBM Final Real-time Localization
- GRB 190508A: Fermi GBM Final Real-time Localization
- GRB 190507B: GOTO optical counterpart search
- LIGO/Virgo S190426c (BHNS candidate): Implications from Numerical Relativity
- GRB 190501A: Swift XRT and UVOT Observations
- IceCube-190504A: Swift-XRT Follow-up Observations
- IceCube-190503A: Swift-XRT Follow-up Observations
- LIGO/Virgo S190503bf: CALET Observations
- Fermi-LAT Gamma-ray Observations of IceCube-190504A
- LIGO/Virgo S190503bf: Swift/BAT Counterpart Search
- LIGO/Virgo S190503bf: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190503bf: ANTARES neutrino search
- LIGO/Virgo S190503bf: AGILE-GRID Observations
- IceCube-190503A: INTEGRAL prompt observation
- LIGO/Virgo S190503bf: INTEGRAL prompt observation
- GRB 190501A: Swift ToO observations
- GRB 190501A: GOTO optical counterpart search
- LIGO/Virgo S190425z: Insight-HXMT observation and counterpart search
- LIGO/Virgo S190426c: GROWTH India follow-up of GRAWITA transient
- LIGO/Virgo S190412m: Further J-GEM optical/NIR observations
- LIGO/Virgo S190425z: 1.3-m optical imaging of UVOT transient field
- Fermi GRB190429.74 Global MASTER-Net observations report
- LIGO/Virgo S190426c: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190426c: GRAWITA transients from Asiago Schmidt wide field observations
- LIGO/Virgo S190425z: DECam Observations of the UVOT Candidate Region
- LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
- GRB 190427A: Swift/UVOT Upper Limits
- LIGO/Virgo S190426c: Continued infrared wide-field search with Palomar Gattini-IR
- LIGO/Virgo S190425z: 1.5m OSN and 10.4m imaging of the UVOT source field
- LIGO/Virgo S190425z: NOT photometry of ZTF19aasckkq
- LIGO/Virgo S190426c: GROWTH India follow-up
- LIGO/Virgo S190426c: DDOTI/OAN Optical Observations
- LIGO/Virgo S190425z: No Optical Detection of the Swift/UVOT Transient with Las Cumbres Observatory
- LIGO/Virgo S190426c: J-GEM optical/NIR follow-up observations
- LIGO/Virgo S190426c: MMT Follow-Up Observations
- LIGO/Virgo S190426c: GOTO optical coverage - no notable counterparts
- GRB 190427A: Lick/Nickel telescope optical observations
- LIGO/Virgo S190426c: Lick/KAIT Follow-Up Observations
- GRB 190427A: COATLI Optical Observations
- LIGO/Virgo S190426c: CNEOST Optical Observations
- LIGO/Virgo S190425z: CNEOST Optical Observations
- LIGO/Virgo S190426c: Infrared Wide-field Search with Palomar Gattini-IR
- LIGO/Virgo S190426c: Optical Wide-field Search with the Zwicky Transient Facility
- GRB 190427A: RATIR Optical and NIR Observations
- LIGO/Virgo S190426c: Nanshan/NEXT Observation of Galaxies
- LIGO/Virgo S190426c: Hobby-Eberly Telescope VIRUS observations of target galaxies.
- ANTARES follow-up of the GW candidate S190426c
- LIGO/Virgo S190425z: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190427A: NOT optical observations
- GRB 190427A: Swift-XRT observations
- LIGO/Virgo S190426c: GROWTH India follow-up
- LIGO/Virgo S190425z: GRANDMA follow-up observations with Les Makes-T60, AZT-8 and Abastumani-T70
- LIGO/Virgo S190426c: Swift/BAT Counterpart Search
- LIGO/Virgo S190426c: AGILE-GRID Observations
- LIGO/Virgo S190425z: Further MMT Follow-Up Observations
- LIGO/Virgo S190426c: INTEGRAL prompt observation
- Baksan Neutrino Observatory Alert 190405.62: Global MASTER-Net:LIGO/Virgo S190425z: PanSTARR OT AT2019ebq/PS19qp
- LIGO/Virgo S190425z: Pierre Auger Observatory follow-up
- LIGO/Virgo S190426c: HAWC follow-up
- LIGO/Virgo S190425z: GROND observations of AT2019ebq/PS19qp
- LIGO/Virgo S190425z: GOTO observations
- LIGO/Virgo S190425z : IRSF/SIRIUS NIR photometry of ZTF19aarykkb and ZTF19aarzaod
- LIGO/Virgo S190425z - ePESSTO+ NTT observations
- LIGO/Virgo S190425z - GROWTH-India follow-up of two ZTF candidates
- LIGO/Virgo S190425z: OVRO-LWA simultaneous low frequency radio observations of localization region
- LIGO/Virgo S190425z: J-GEM optical follow-up observations with Subaru/FOCAS
- LIGO/Virgo S190425z: Xinglong/Schmidt follow-up observations
- LIGO/Virgo S190425z: Palomar Gattini-IR wide-field infrared follow-up
- LIGO/Virgo S190425z: AGILE-GRID Observations
- LIGO/Virgo S190425z: Swift/BAT Counterpart Search
- LIGO-Virgo S190425z: AGILE MCAL observation
- LIGO/Virgo S190425z: Lick/KAIT Follow-Up Observations
- LIGO/Virgo S190425z: Hobby-Eberly Telescope VIRUS observations of target galaxies.
- LIGO/Virgo S190421ar: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/VirgoS190425z: HAWC follow-up
- LIGO/Virgo S190425z: SAGUARO follow-up observations
- LIGO/Virgo S190425z: INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190421ar: Lick/KAIT Follow-Up Observations
- GRB 190422A: Swift/UVOT Upper Limits
- LIGO/Virgo S190421ar: Swift/BAT Counterpart Search
- LIGO/Virgo S190421ar/G330308: ANTARES neutrino search
- LIGO/Virgo S190421ar: INTEGRAL prompt observation