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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"- GRB190219A: MASTER Global Robotic Net optical observation
- GRB 190219A: BOOTES-1 optical limits
- GRB 190219A: Prompt enhanced Swift-XRT position
- GRB 190219A: Swift detection of a burst
- GRB 190215A: AstroSat CZTI detection
- Trigger 889483: Swift detection of Swift J1858.6-0814
- GRB 190215A: Insight-HXMT/HE detection
- GRB 190215A: Fermi GBM detection
- GRB 190212A: Insight-HXMT/HE detection
- GRB190211A: GROWTH-India detection of optical afterglow
- GRB 190211A: Tautenburg observations
- GRB 190211A: Swift/UVOT Detection
- GRB 190211A: DOAO optical observation
- GRB 190206A: AstroSat CZTI detection
- GRB190211A: MITSuME Akeno optical observation
- GRB 190211A: NOT optical observations
- GRB 180703A: VLT/MUSE host galaxy redshift measurement
- GRB 190211A: Swift-XRT refined Analysis
- GRB 190211A: Swift-BAT refined analysis
- GRB 190211A: BOOTES-4/MET optical afterglow confirmation
- GRB190211A: MASTER Global Robotic Net optical observation
- GRB 190211A: NEXT-0.6m optical afterglow detection
- GRB 190211A: Swift detection of a burst
- Trigger 888312: Swift detection of 4U 1901+03
- GRB 190202A: Terskol 2-m optical observations
- Konus-Wind observation of GRB 190206A
- IPN Triangulation of GRB 190206A (short/extremely bright)
- GRB 190203A: Mondy optical observations
- GRB 190204A: CALET Gamma-Ray Burst Monitor detection
- Retraction of IceCube GCN/AMON NOTICE 36142391_132143
- GRB 190202A: AstroSat CZTI detection
- GRB190202A: GROWTH-India detection of optical afterglow
- GRB 190203A: Swift-BAT refined analysis
- GRB 190204A: Swift-BAT refined analysis
- GRB 190202A: Xinglong-2.16m optical observations
- GRB 190202A: SAO RAS further optical observations
- Konus-Wind observation of GRB 190204A
- GRB 190204A: SAO RAS optical observations
- GRB 190204A: Mondy optical upper limit
- GRB 190203A: AstroSat CZTI detection
- GRB190203A: UVOT analysis
- GRB 190203A: COATLI Optical Observations
- GRB 190204A: Swift/UVOT Detection
- GRB 190204A: Enhanced Swift-XRT position
- GRB 190204A: COATLI Optical Detection of the Fading Afterglow
- GRB 190203A: Liverpool Telescope near-IR observations
- Konus-Wind observation of GRB 190203A
- GRB 190203A: Swift-XRT refined Analysis
- GRB 190204A: Swift-XRT refined Analysis
- GRB 190204A: AstroSat CZTI detection
- Swift Trigger 887541: MASTER inspect
- GRB 190204A: MAXI/GSC detection
- GRB 190202A: R and I band observation from HCT
- GRB 190204A: Swift detection of a burst with a possible optical counterpart
- Swift Trigger 887541: MASTER optical observation
- GRB 190203A: MASTER OT detection
- Swift Trigger 887541: Swift detection of Swift J1728.9-3613
- GRB 190203A: Enhanced Swift-XRT position
- GRB 190203A: SAO RAS optical observations, afterglow fading
- GRB 190203A: Koshka Zeiss-1000 optical upper limit
- GRB 190203A: Swift detection of a burst with an optical counterpart
- GRB 190202A: SAO RAS optical observations
- GRB 190202A: TSHAO optical observations
- GRB 190202A: NOT optical observations
- GRB 190202A: McDonald 0.8-m telescope optical observation
- GRB 190202A: Swift-XRT refined Analysis
- GRB 190202A: LCO-CTIO optical observations
- GRB 190202A: Fermi GBM observation
- Fermi GBM trigger 570825115/190202772 is not a GRB
- GRB 190202A, Swift-BAT refined analysis
- GRB 190202A: AGILE ratemeters detection
- GRB 190202A: Swift/UVOT Detection
- GRB 190202A: GOTO optical observations
- GRB 190202A: Enhanced Swift-XRT position
- GRB 190202A: Koshka Zeiss-1000 optical observations
- GRB 190202A: Swift detection of a burst with an optical counterpart
- Fermi GBM trigger 570716645/190201517 is not a GRB
- GRB 190131A: Insight-HXMT/HE detection
- GRB 190131A: AstroSat CZTI detection
- GRB 190126A: AstroSat CZTI detection
- Fermi GBM trigger 570659556/190131856 is not a GRB
- GRB 190129B: Insight-HXMT/HE detection
- GRB 190114C: JCMT SCUBA-2 sub-mm observations
- Improved IPN error box for GRB 190129B
- GRB 190129B: GOTO optical observations
- GRB 190129B: DDOTI Detection of the Possible Afterglow and Suggestion of Fading
- GRB 190129B: Swift/UVOT Upper Limits
- GRB 190129B: ePESSTO NTT optical observations
- GRB 190129B: AstroSat CZTI detection
- GRB 190129B: MASTER Global Robotic Net optical observation
- GRB 190129A: CALET Gamma-Ray Burst Monitor detection
- GRB 190129B: GROND possible host candidate
- GRB 190129B: Swift-XRT candidate afterglow detection
- GRB 190129B: Tiled Swift observations
- Fermi GBM Observations of IceCube-190124A
- GRB 190129A: Fermi GBM detection
- Konus-Wind observation of extremely bright GRB 190129B
- IPN Triangulation of GRB 190129B (long/extremely bright)
- INTEGRAL observation of IceCube-190124A
- GRB 190129A: MAXI/GSC detection