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"- GRB 180705A: Swift-BAT refined analysis
- GRB 180705A: Enhanced Swift-XRT position
- Fermi GBM triggers 552488966/180705548 and 552490104/180705561 are not GRBs
- GRB 180705A: MASTER optical observation
- GRB 180705A: Swift-XRT observations
- GRB 180705A: Swift detection of a burst
- GRB 180704A: AstroSat CZTI detection
- GRB 180703A: AstroSat CZTI detection
- GRB 180704B: CALET Gamma-Ray Burst Monitor detection
- GRB 180703A: Swift/UVOT Upper Limits
- GRB 180703B: Fermi GBM detection
- GRB 180703A: Fermi GBM detection
- GRB 180704A: Swift-XRT refined Analysis
- GRB 180704A: Swift-BAT refined analysis
- GRB 180704A: Swift/UVOT Upper Limits
- GRB 180703A: LCO Sutherland possible optical candidate
- GRB 180703A: Swift-XRT observations
- GRB 180704A: Enhanced Swift-XRT position
- GRB150101B: INTEGRAL prompt gamma-ray signal from a possible GRB170817A-analogue
- GRB 180703B: CALET Gamma-Ray Burst Monitor detection
- GRB 180704A: Swift-XRT observations
- GRB 180704A: MASTER optical observation
- GRB 180704A: Swift detection of a burst
- GRB 180703B: Fermi-LAT detection
- GRB 180703A: Fermi-LAT detection
- GRB 180703A: Tiled Swift observations
- GRB 180630A: Swift/UVOT Detection
- GRB 180701A: MAXI/GSC detection
- GRB 180626C : GOTO optical observations
- GRB 180626B : GOTO optical observations
- GRB 180630A: Swift-BAT refined analysis
- GRB 180630A: Swift-XRT refined Analysis
- GRB 180630A: Fermi GBM detection
- GRB 180626C / Fermi trigger 551697835: MASTER inspection
- GRB 180630A: Enhanced Swift-XRT position
- GRB 180630A: Swift detection of a burst with an optical counterpart
- GRB 180626C: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 551697835)
- GRB 180626A: TSHAO optical upper limit
- Konus-Wind observation of GRB 180626A
- Konus-Wind observation of GRB 180626C
- GRB 180624A: NOT optical counterpart
- Konus-Wind observation of GRB 180626B
- GRB 180626A: RATIR Optical Observations
- IPN Triangulation of GRB 180626C (short)
- IPN Triangulation of GRB 180626B (short)
- GRB 180626A: Swift-BAT refined analysis
- GRB 180626A: KAIT Optical Upper Limit
- GRB 180626A: Swift-XRT refined Analysis
- GRB 180626A: COATLI Optical Detection
- GRB 180624A: LCO Haleakala observations
- GRB 180626A: Swift/UVOT Detection
- Konus-Wind observation of GRB 180623A
- GRB 180626A: RATIR Optical Detection
- GRB 180626A: LCO Haleakala observations
- GRB 180626A: ISON-MN optical observations
- GRB 180626A: Enhanced Swift-XRT position
- GRB 180626A: A long GRB detected by INTEGRAL
- GRB 180626A: Swift detection of a burst with an optical counterpart
- GRB 180623B: CALET Gamma-Ray Burst Monitor detection
- GRB 180624A: Swift-BAT refined analysis
- AT2018cow: Swift/BAT data search
- GRB 180624A: RATIR Optical Observations
- GRB 180624A: LBT/MODS redshift measurement
- GRB 180620B: AstroSat CZTI detection
- GRB 180620A: AstroSat CZTI detection
- GRB 180618A: AstroSat CZTI detection
- GRB 180613A: LCO Afterglow detection
- GRB 180624A: GROND observations
- GRB 180624A: LCO Siding Springs afterglow candidate
- GRB 180624A: MITSuME Okayama optical upper limits
- GRB 180624A: Swift-XRT refined Analysis
- GRB 180624A: Swift/UVOT Upper Limits
- GRB 180624A: Enhanced Swift-XRT position
- GRB 180623A: retraction of the Swift/UVOT Detection
- GRB 180623A: Swift-BAT refined analysis
- GRB 180624A: Swift detection of a burst
- GRB 180623A: Swift/UVOT Detection
- GRB 180623A: Swift-XRT refined Analysis
- GRB 180623A: Enhanced Swift-XRT position
- GRB 180623A: Swift detection of a burst
- GRB 180620B: Swift/UVOT Detection
- GRB 180620A iTelescope observation
- Konus-Wind observation of GRB 180620B
- Konus-Wind observation of GRB 180620A
- GRB 180620B: VLT/X-shooter redshift
- Konus-Wind observation of GRB 180618A (a short GRB with extended emission)
- GRB 180620B: Swift-BAT refined analysis
- GRB 180613A: Afterglow confirmation and added photometry
- GROND observations of GRB 180620B
- GROND observations of GRB 180620A
- GRB 180620B: Swift-XRT refined Analysis
- GRB 180618B: CALET Gamma-Ray Burst Monitor detection
- GRB 180620A: Swift-BAT refined analysis
- GRB 180620B: Enhanced Swift-XRT position
- GRB 180620B: Fermi GBM detection
- GRB 180620A: KAIT Optical Observations
- GRB 180620A: Xinglong-2.16m optical observations
- GRB 180618A: Swift/UVOT Detection
- GRB 180618A: TSHAO optical upper limit
- GRB 180620A: Swift-XRT refined Analysis