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"19612 results found.
- GRB 220701A: Swift-XRT refined Analysis
- GRB 220701A: LCO Optical Upper Limits
- GRB 220701A: BOOTES-5/JGT early optical upper limit
- GRB 220701A: Swift/UVOT Upper Limits
- GRB 220701A: Enhanced Swift-XRT position
- GRB 200701A: KAIT Optical Upper Limit
- GRB 220701A: Swift detection of a burst
- GRB 220627A: Swift/UVOT Upper Limits
- GRB 220627A: Swift-XRT afterglow detection
- Konus-Wind detection of GRB 220627A
- Trigger 1113743: Swift detection of MAXI J0655-013
- IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
- Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
- GRB 220627A: MeerLICHT candidate optical afterglow
- GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
- GRB 220627A: Swift/BAT-GUANO detection outside the coded FOV
- Konus-Wind detection of GRB 220624A
- GRB 220627A: Swift ToO observations
- GRB 220627A: Fermi-LAT detection
- GRB 220623A: GIT optical upper limits.
- GRB 220624A: CALET Gamma-Ray Burst Monitor detection
- GRB 220624A: Fermi GBM Detection
- IPN triangulation of GRB 220624A
- GRB 220623A: Swift-BAT refined analysis
- GRB 220624A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
- Konus-Wind detection of GRB 220623A
- GRB 220623A: AbAO optical upper limit
- GRB 220623A: Swift-XRT refined Analysis
- GRB 220623A: Swift/UVOT Upper Limits
- GRB 220623A: BOOTES-5/JGT optical afterglow detection
- GRB 220623A: Enhanced Swift-XRT position
- GRB 220623A: AGILE detection
- GRB 220623A: AstroSat CZTI detection
- GRB 220623A: Swift-XRT observations
- GRB 220623A: Swift detection of a burst
- GRB 220618A: Fermi GBM detection
- Swift Detection of MAXI J0655-013
- GRB 220618A: Swift-BAT refined analysis
- GRB 220618A: iTelescope T-19 upper limit
- Swift GRB220620.02: Global MASTER-Net observations report
- GRB 220611A: Continued Gemini Infrared Observations
- GRB 220617A: TNG optical observations
- Swift Trigger 1110865 is probably not an astrophysical event
- GRB 220618A: Swift-XRT refined Analysis
- IPN triangulation of GRB 220617A (short)
- GRB 220618A: BOOTES-5/JGT early optical upper limit
- GRB 220618A: Swift/UVOT Upper Limits
- GRB 220618A: Enhanced Swift-XRT position
- GRB 220617A: Swift-XRT observations
- GRB 220618A: Swift detection of a burst
- Swift GRB220618.38: Global MASTER-Net observations report
- GRB 220617A: Fermi-LAT detection
- GRB 220617B: Swift ToO observations
- GRB 220611A: Swift/UVOT Upper Limits
- GRB 220612A: CALET Gamma-Ray Burst Monitor detection
- GRB 220612A: Swift/BAT-GUANO detection
- GRB 220611A: Swift-BAT refined analysis
- Swift GRB 220611A: Global MASTER-Net observations report
- GRB 220611A: Swift-XRT refined Analysis
- GRB 220611A: Enhanced Swift-XRT position
- GRB 220611A: Swift detection of a burst
- GRB 220606A: Fermi GBM observation
- GRB 220606B: Gemini South Optical Observations
- GRB 220606B: Fermi GBM Observation
- GRB 220606B: Swift follow-up observations
- GRB 220606A: Swift/BAT-GUANO detection
- GRB 220606B: GUANO coordinate correction to GCN 32167
- GRB 220527A: A BdHN I with a clear UPE phase
- GRB 220606B: Swift ToO observations
- GRB 220606B: Swift/BAT-GUANO candidate arcminute localization of a short burst
- GRB 220603A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220527A: MITSuME Akeno continued optical observation
- Konus-Wind detection of GRB 220528A
- IPN triangulation of GRB 220528A (short)
- GRB 220528A: Fermi GBM Observation
- Trigger 1108538: Swift detection of a burst from SGR J1935+2154
- Swift trigger 1108515 is not an astrophysical event
- Correction to GCN 32148: Should be GRB 220528A
- GRB 220528B: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220527A: AST3-3 Yaoan Optical Observation
- GRB 220527A: VLT/X-shooter spectroscopic redshift
- GRB 220527A: AstroSat CZTI detection
- GRB 220527A: MITSuME Akeno optical observation
- GRB 220527A: Swift/UVOT detection
- GRB 220527A: Swift-XRT afterglow detection
- Swift trigger 1108208 is not an interesting astrophysical event.
- GRB 220527A: Swift ToO observations
- Swift GRB220526.48: Global MASTER-Net observations report
- IPN triangulation of GRB 220524A
- GRB 220521A: BOOTES-2/TELMA and CAHA 2.2m telescope optical upper limit
- GRB 220521A: classification and detection by SPI-ACS/INTEGRAL
- GRB 220521A: MMT Afterglow Imaging
- GRB 220514A: Swift/BAT-GUANO detection outside the coded FOV
- GRB 220521A: Swift-BAT refined analysis
- GRB 220521A: Fermi GBM detection
- GRB 220521A: RATIR Optical and NIR Observations
- GRB 220521A: Swift-XRT refined Analysis
- GRB 220521A: Swift/UVOT Upper Limits
- GRB 220521A: Enhanced Swift-XRT position