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.
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subject:"Swift"body:"GRB"submitter:"Judith Racusin"- Konus-Wind observation of GRB 180404B
- Chandra observations of GRB161219B 400 days after the explosion
- GRB 180404C CALET Gamma-Ray Burst Monitor detection
- Fermi GBM triggers 544628550/180405571, 544542853/180404579, 544531428/180404447 are not GRBs
- GRB 180404A: Swift/UVOT Detection
- GRB 180404A: LCO FTS observations
- GRB 180404A: Swift-XRT refined Analysis
- GRB 180404B: Swift-BAT refined analysis
- GRB 180402A: Fermi GBM refined spectral analysis
- GRB 180404A: Swift-BAT refined analysis
- GRB 180404B: Swift-XRT refined Analysis
- GRB 180404B: Fermi GBM observation
- GRB 180404B: MASTER-OAFA OT observation
- Fermi GBM triggers 544440014/180403389 and 544451446/180403521 are not GRBs
- GRB 180404B: Enhanced Swift-XRT position
- GRB 180404A: MASTER-OAFA OT observation
- GRB 180404A: Enhanced Swift-XRT position
- GRB 180404A: VLT/X-shooter redshift
- GRB 180404B: Swift detection of a burst with an optical counterpart
- GRB 180404A: Swift detection of a burst with an optical afterglow
- Konus-Wind observation of GRB 180402A
- GRB 180402A: Swift/UVOT Upper Limits
- GRB 180402A: Swift-XRT refined Analysis
- GRB 180402A: Fermi GBM detection
- GRB 180402A, Swift-BAT refined analysis
- GRB 180402A: KAIT Optical Upper Limit
- GRB 180402A: RATIR Upper Limits
- GRB 180402A: LCO McDonald observations
- GRB 180402A: Swift detection of a possibly short burst
- GRB 180331B: Swift/UVOT Upper Limits
- GRB 180331B: Swift-XRT refined Analysis
- GRB 180331B: AbAO optical observations
- GRB 180331B: Swift-BAT refined analysis
- GRB 180331B: Enhanced Swift-XRT position
- GRB 180331A: Swift-BAT refined analysis
- GRB 180331B: Swift detection of a burst
- GRB 180331A: Swift-XRT refined Analysis
- GRB 180329B: LCO FTS observations
- GRB 180331A: Swift/UVOT Upper Limits
- GRB 180331A: Enhanced Swift-XRT position
- GRB 180331A: Swift detection of a burst
- GRB 180329B: VLT/X-shooter spectroscopic observations
- GRB 180329B: Swift-BAT refined analysis
- GRB 180329B: Swift/UVOT Detection
- GRB 180329B: RATIR Optical Observations
- Swift Trigger 819863 is not a GRB
- GRB 180329B: NOT optical afterglow detection
- GRB 180329A: Swift-BAT refined analysis
- GRB 180329B: Swift-XRT refined Analysis
- GRB 180329B: Enhanced Swift-XRT position
- GRB 180329B: Swift detection of a burst with an optical afterglow
- GRB180325A: AstroSat CZTI detection
- Swift Trigger 819301: possible GRB 180329A
- GRB 180325A: VLT/X-shooter spectroscopic observations
- Konus-Wind observation of GRB 180318A
- Konus-Wind observation of GRB 180326A
- Konus-Wind observation of GRB 180317A
- GRB 180325A: further NOT observations
- IPN Triangulation of GRB 180326A (long)
- GRB 180325A: Swift/UVOT Detection
- Konus-Wind observation of GRB 180316A
- Konus-Wind observation of GRB 180324A
- Konus-Wind observation of GRB 180325A
- GRB 180325A, Swift-BAT refined analysis
- GRB 180325A: GROND observations
- GRB 180325A: Global MASTER-Net OT prompt observations
- GRB 180325A: TAROT Calern observatory optical observations
- GRB 180325A: D50 early optical follow-up
- GRB 180325A: Swift-XRT refined Analysis
- GRB 180325A: Enhanced Swift-XRT position
- GRB 180325A: Optical Photometry with SLKT
- GRB 180325A: RATIR Optical Observations
- GRB 180325A: prompt REM optical/NIR detection
- GRB 180325A: NOT redshift
- GRB 180325A: prompt LT observations
- GRB 180324A, Swift-BAT refined analysis
- GRB 180325A: Swift detection of a burst with an optical counterpart
- GRB 180324A: Swift/UVOT Upper Limits
- GRB 180324A: Swift-XRT refined Analysis
- GRB 180324A: Enhanced Swift-XRT position
- GRB 180324A: RATIR Optical Observations and Possible Afterglow Detection
- GRB 180324A: KAIT Optical Upper Limit
- GRB 180324A: Prompt enhanced Swift-XRT position
- GRB 180324A: Swift detection of a burst
- IBAS Alert n. 8033: Not a GRB
- IPN Triangulation of GRB 180318A (long)
- IPN Triangulation of GRB 180317A (short/hard)
- IBAS Alert n. 8032: Not a GRB
- GRB 180316A: RATIR Optical Observations
- GRB 180316A: MITSuME Akeno optical upper limits
- GRB 180316A: MITSuME Okayama optical upper limits
- GRB 180316A: TSHAO optical observations
- GRB 180314A: AstroSat CZTI detection
- GRB 180316A: RATIR Optical Observations, Possible Re-brightening
- Konus-Wind observation of GRB 180314A
- GRB 180316A: Swift-BAT refined analysis
- GRB 180316A: Swift-XRT refined Analysis
- GRB 180316A: Swift/UVOT Detection
- GRB 180316A: RATIR Optical Observations
- GRB 180316A: Enhanced Swift-XRT position