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.
Lucene Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
588 results found.
- Fermi-LAT gamma-ray observations of IceCube-250421A
- GRB 250327A: Swift-XRT refined Analysis
- GRB 250327A: SVOM/VT optical candidate
- GRB 250322A: AstroSat CZTI detection of a short burst
- Fermi trigger No 763509110: Global MASTER-Net observations report
- Fermi GRB 250309B: Global MASTER-Net observations report
- GRB 250226A: Fermi GBM Observation
- Fermi GRB 250223A: Global MASTER-Net observations report
- GRB 250211A: SVOM trigger sb25021103 is not a GRB
- LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
- LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
- GRB 250207A: REM IR afterglow detection
- GRB 250207A: REM optical afterglow detection
- GRB 250114B: OHP/T193 optical upper limit
- GRB 241229B: NUTTelA-TAO / BSTI Optical Limits
- GRB 241207C: MASTER optical observations
- Fermi trigger No 755225799: Global MASTER-Net observations report
- Swift GRB 241128A: Global MASTER-Net observations report
- Swift GRB241127.91: Global MASTER-Net observations report
- GRB 241113A: Swift/UVOT Detection
- GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
- Fermi GRB 240918A: Global MASTER-Net observations report
- EP EP240913a: Global MASTER-Net observations report
- GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
- GRB 240829A: Swift-BAT refined analysis
- LAT GRB240828.62: Global MASTER-Net observations report
- Fermi trigger No 745866488: Global MASTER-Net observations report
- Fermi trigger No 745057312: Global MASTER-Net observations report
- Swift GRB 240811A: Global MASTER-Net observations report
- GRB 240727C: AstroSat CZTI detection of a long burst
- Konus-Wind detection of GRB 240627A
- Fermi GRB 240702A: Global MASTER-Net observations report
- Fermi trigger No 741211696: Global MASTER-Net observations report
- Swift Trigger 1232465: consistent with noise
- Konus-Wind detection of GRB 240529A
- GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
- GRB 240419B: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
- LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
- LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
- Swift GRB 240419B: Global MASTER-Net observations report
- GRB 240414A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
- Swift Trigger 1220736: detection of 4U 1543-62.
- Fermi GRB 240408A: Global MASTER-Net observations report
- Konus-Wind detection of LXT 240402A/GRB 240402B
- Konus-Wind detection of GRB 240303B
- GRB 240109A: Swift-BAT refined analysis
- GRB 231215A: radio detection with the VLA
- GRB 231129A: Swift-BAT refined analysis
- GRB 231129A: BOOTES-5/JGT optical upper limit
- GRB 231118A: Swift-BAT refined analysis
- GRB 231111A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
- IceCube Alert 231027.18: Global MASTER-Net observations report
- GRB 230911C: Swift-BAT refined analysis
- GRB 230826A: Swift-BAT refined analysis
- GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- Fermi GRB 230827A: Global MASTER-Net observations report
- Swift GRB230825.75: Global MASTER-Net observations report
- Fermi GRB 230814A: Global MASTER-Net observations report
- Swift GRB230728.12: Global MASTER-Net observations report
- LIGO/Virgo S230622e: Global MASTER-Net observations report
- LIGO/Virgo S230615be: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
- GRB 230430A: AstroSat CZTI detection
- IPN triangulation of GRB 230418A (short)
- Fermi GRB 230402A: Global MASTER-Net observations report
- Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
- Fermi GRB 230227A: Global MASTER-Net observations report
- Fermi GRB 230215A: Global MASTER-Net observations report
- GRB 221231A: Fermi GBM Observation
- GRB 230101A: AstroSat CZTI detection
- Fermi GRB 221223A: Global MASTER-Net observations report
- GRB 221216A: Swift-XRT refined Analysis
- Fermi trigger No 687190301: Global MASTER-Net observations report
- GRB 220831A: ATCA 5/9 GHz radio observations
- GRB 220711B: Fermi GBM Detection
- GRB 220624A: Fermi GBM Detection
- Fermi GRB 220623B: Global MASTER-Net observations report
- GRB 220623A: Swift-XRT observations
- Konus-Wind detection of an intermediate flare from SGR 1935+2154 on June 16
- Swift GRB220521.97: Global MASTER-Net observations report
- GRB 220514B: MAXI/GSC detection
- Fermi-LAT Gamma-ray Observations of IceCube-220509A
- MAXI GRB220506.27: Global MASTER-Net observations report
- IceCube Alert 220501.95: Global MASTER-Net observations report
- GRB 220319A: Mondy optical uper limit
- GRB 220315A: MASTER Global Robotic Net optical observations
- Konus-Wind detection of GRB 220310A
- Fermi trigger No 668410535: Global MASTER-Net observations report
- Swift GRB 220306B: Global MASTER-Net observations report
- Konus-Wind observation of GRB 220219B
- GRB 220210A: BOOTES-5/JGT optical afterglow candidate
- GRB 220130A: Fermi GBM Observation
- Konus-Wind detection of GRB 220107A
- Konus-Wind detection of GRB 210928A
- Swift GRB 210919A: Global MASTER-Net observations report
- Konus-Wind detection of GRB 210905A