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 180718B: Swift ToO observations
- GRB 180718B: Fermi-LAT detection
- GRB 180718A: Fermi GBM detection
- GRB 180718A short GRB detected by IPN and found in ground analysis of BAT data
- Swift Trigger 848621 is not an astrophysical event
- Trigger 848584: Swift detection of AX 1631.9-4752
- GRB 180715A: CALET Gamma-Ray Burst Monitor detection
- GRB 180715A: LCO Sutherland observations
- GRB 180715A: COATLI Optical Observations
- GRB 180715A: Swift-XRT observations
- GRB 180715A: Fermi GBM detection
- GRB 180715A: Swift-BAT refined analysis
- GRB 180715A: GOTO optical limits
- GRB 180715A: LCO Sutherland possible optical candidate
- GRB 180715A: Swift-XRT observations
- GRB 180715A: Swift detection of a short hard burst
- GRB180714A: a long GRB detected by INTEGRAL
- IceCube-171106A: MASTER optical observation
- GRB 180703A: optical afterglow confirmation
- GRB 180711A: CALET Gamma-Ray Burst Monitor detection
- IceCube-170922A: First Optical observations of the Neutrino Trigger by MASTER Global Net and 25 IceCube alerts inspection.
- GRB 180705A: OSN observations
- Swift Trigger 847216: misidentification of IGR J16385-2057
- GRB 180709A: BOOTES-5/JGT optical observations
- GRB 180709A: Swift-BAT refined analysis
- GRB 180709A: Swift/UVOT Upper Limits
- GRB 180709A: Swift-XRT refined Analysis
- GRB 180709A: Optical limits
- GRB 180709A: COATLI Optical Observations
- GRB 180709A: Enhanced Swift-XRT position
- GRB 180703B: further analysis of CGBM data
- GRB 180703A: Swift-XRT afterglow detection
- GRB 180709A: Swift detection of a burst
- GRB 180705A: RTT150 optical upper limit
- Trigger 846740: Swift trigger near NGC5055
- Konus-Wind observation of GRB 180703A
- GRB 180703A: MASTER optical observation
- IPN Triangulation of GRB 180703A
- GRB 180706A: GOTO optical limits
- GRB 180706A: TSHAO optical observations
- GRB 180706A: Swift/UVOT Detection
- GRB 180706A: Swift-BAT refined analysis
- GRB 180705A: Swift-XRT refined Analysis
- GRB 180706A: Fermi GBM observation
- Konus-Wind observation of GRB 180704A
- GRB 180706A: Swift-XRT refined Analysis
- GRB 180706A: Enhanced Swift-XRT position
- Konus-Wind observation of GRB 180701A
- Konus-Wind observation of GRB 180703B
- GRB 180705A: TSHAO optical upper limit
- GRB 180705A: Swift/UVOT Upper Limits
- GRB 180705A: RATIR Optical Observations
- GRB 180706A: COATLI Optical Detection
- GRB 180706A: Swift detection of a burst with optical counterpart
- IPN Triangulation of GRB 180703B
- 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)