GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"21525 results found.
- GRB 211023B: MITSuME Akeno optical upper limits
- GRB 211024A: 1.3m DFOT observations
- IPN triangulation of GRB 211022A
- GRB 2121023B: 6 GHz VLA radio upper limit
- AMON NuEm-211020A: No Candidate Counterparts from Swift-XRT follow up observations
- GRB 211024A: Swift-XRT source 4 is not an afterglow.
- GRB 211023B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
- GRB 211024A: Possible afterglow candidate from GIT
- GRB 211024A: Swift-XRT observations
- GRB 211024A: Fermi GBM detection
- GRB 211018A: Swift-XRT observations
- GRB 211025A: Optical Afterglow Detection
- GRB 211024A: Swift ToO observations
- GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
- GRB 211024B: Swift/UVOT detection
- Swift GRB 211025A: Global MASTER-Net observations report
- GRB 211023B: LDT Optical Afterglow Detection
- GRB 211025A: Swift-BAT refined analysis
- GRB 211025A: Swift-XRT refined Analysis
- GRB 211024B: CAHA 2.2m Detection; ultra-long GRB?
- GRB 211024B: Swift-XRT refined Analysis
- Possible Short GRB 211023B: CAHA 2.2m Detection
- GRB 211025A: Swift/UVOT Detection
- GRB 211024B: Swift-BAT refined analysis
- GRB 211025A: Enhanced Swift-XRT position
- GRB 211025A: Swift detection of a burst
- GRB 211024B: Nanshan/NEXT optical afterglow detection
- GRB 210919A: FORS2/VLT observations
- Swift GRB 211024B: Global MASTER-Net observations report
- GRB 211024B: Swift detection of a burst
- GRB 211023B: Swift-BAT refined analysis
- GRB 211023B: BOOTES-4/MET and 1.5m OSN optical upper limit
- GRB 211023B: Swift/UVOT Detection
- GRB 211023B: TSHAO optical observation
- GRB 211023B: Swift-XRT refined Analysis
- GRB 211023B: Enhanced Swift-XRT position
- Swift GRB 211023B: Global MASTER-Net observations report
- GRB 211023A: Fermi-LAT detection
- GRB 211023B: Swift detection of a possibly short burst with an optical counterpart
- IPN Triangulation of GRB 210927B
- GRB 211018A: Swift ToO observations
- BepiColombo MGNS joins the IPN
- GRB 211018A: Fermi-LAT detection
- Swift GRB211017.99: Global MASTER-Net observations report
- Swift trigger 1078701: MITSuME Akeno optical upper limits
- GRB 210919A: LDT optical observations and candidate host galaxies
- Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
- Swift GRB211010.45: Global MASTER-Net observations report
- Swift Trigger 1078701 is probably not a GRB
- GRB 210928A: MeerKAT detection
- Correction to GCN 30915: GRB 210928A: Swift-XRT analysis
- GRB 210928A: Kinder SLT-40cm optical limits
- GRB 210930A: Swift-BAT refined analysis
- SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
- GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
- GRB 210928A: Swift-XRT refined Analysis
- GRB 210928A: Fermi-LAT detection
- Swift GRB211001.03 / trigger 1076121 : MASTER OT retraction
- GRB 210930A: CAHA 2.2m telescope optical limit
- Swift GRB211001.03: Global MASTER-Net observations report
- Swift Trigger 1076121 is not a GRB
- Swift GRB211001.03: Global MASTER-Net OT detection
- GRB 210930A: Swift/UVOT Upper Limits
- GRB 210930A: Swift-XRT refined Analysis
- Swift GRB 210930A: Global MASTER-Net observations report
- GRB 210930A: Enhanced Swift-XRT position
- GRB 210930A: Swift detection of a burst
- IPN triangulation of GRB 210925B
- GRB 210919A: iTelescope T-11 upper limits
- GRB 210919A OSN 1.5m Source Confirmation
- GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
- GRB 210919A: Chandra rapid ToO upper limit
- IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
- GRB 210919A: DECam Upper Limits
- GRB 210919A: Swift-BAT refined analysis
- GRB 210919A: Lowell Discovery Telescope upper limits (correction to GCN 30859)
- GRB210919A: Keck NIRC2 Kp band upper limits
- GRB 210919A: Swift/UVOT Upper Limits
- GRB 210919A: LOAO and LSGT optical upper limits
- GRB 210919A: MITSuME Akeno optical upper limits
- GRB 210919A: Swift-XRT refined Analysis
- GRB 210919A: NOT upper limits
- GRB 210919A: AbAO optical upper limit
- GRB 210919A: Enhanced Swift-XRT position
- GRB 210919A: LCO Optical Upper Limit
- GRB 210919A: BOOTES-2/TELMA optical upper limit
- Swift GRB 210919A: Global MASTER-Net observations report
- GRB 210919A: Swift detection of a short burst
- Swift trigger 1073821: detection of IGR J16418-4532
- GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
- GRB 210912A: Swift-BAT refined analysis
- GRB 210912A: CAHA 2.2m Detection
- GRB 210912A: Swift-XRT refined Analysis
- GRB 210912A: Swift/UVOT Detection
- GRB 210912A: Enhanced Swift-XRT position
- GRB 210912A: Host-galaxy candidate in PanSTARRS
- Swift GRB 210912A: Global MASTER-Net observations report
- GRB 210912A: BOOTES-5/JGT optical afterglow candidate
- GRB 210912A: Swift detection of a burst
- Swift GRB210910.42: Global MASTER-Net observations report