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"19090 results found.
- GRB 180410A: RATIR Optical Observations
- GRB 180411A: Swift detection of a burst
- GRB 180410A: Swift/UVOT Upper Limits
- GRB 180410A: Enhanced Swift-XRT position
- GRB 180410A: Swift detection of a burst or a Galactic transient.
- IPN Triangulation of GRB 180409A
- GRB 180409A: Tiled Swift observations
- GRB 180402A: ISON-NM early optical limits
- GRB 180407A: Swift-BAT refined analysis
- Swift Trigger 823014: TAROT Calern observatory optical observations
- GRB 180407A: COATLI Upper Limits
- Swift Trigger 823014 is probably not a GRB
- GRB 180404B: Swift/UVOT Detection
- Chandra observations of GRB161219B 400 days after the explosion
- GRB 180404A: Swift/UVOT Detection
- GRB 180404B: Fermi GBM observation
- GRB 180404B: Enhanced Swift-XRT position
- GRB 180404A: Enhanced Swift-XRT position
- GRB 180404B: Swift detection of a burst with an optical counterpart
- GRB 180404A: Swift detection of a burst with an optical afterglow
- GRB 180402A: Swift/UVOT Upper Limits
- GRB 180402A: Swift-XRT refined Analysis
- GRB 180402A: Fermi GBM detection
- GRB 180402A: RATIR Upper Limits
- GRB 180402A: Swift detection of a possibly short burst
- GRB 180331B: Swift/UVOT Upper Limits
- GRB 180331B: AbAO optical observations
- GRB 180331B: Enhanced Swift-XRT position
- GRB 180331B: Swift detection of a burst
- GRB 180331A: Swift/UVOT Upper Limits
- GRB 180331A: Enhanced Swift-XRT position
- GRB 180331A: Swift detection of a burst
- GRB 180329B: Swift/UVOT Detection
- GRB 180329B: RATIR Optical Observations
- Swift Trigger 819863 is not a GRB
- GRB 180329B: NOT optical afterglow detection
- GRB 180329B: Enhanced Swift-XRT position
- GRB 180329B: Swift detection of a burst with an optical afterglow
- Swift Trigger 819301: possible GRB 180329A
- GRB 180325A: VLT/X-shooter spectroscopic observations
- GRB 180325A: Swift/UVOT Detection
- GRB 180325A: GROND observations
- GRB 180325A: TAROT Calern observatory optical observations
- GRB 180325A: D50 early optical follow-up
- 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: Swift detection of a burst with an optical counterpart
- GRB 180324A: Swift/UVOT Upper Limits
- GRB 180324A: Enhanced Swift-XRT position
- GRB 180324A: RATIR Optical Observations and Possible Afterglow Detection
- GRB 180324A: Swift detection of a burst
- IPN Triangulation of GRB 180317A (short/hard)
- GRB 180316A: RATIR Optical Observations
- GRB 180316A: TSHAO optical observations
- GRB 180316A: RATIR Optical Observations, Possible Re-brightening
- GRB 180316A: Swift/UVOT Detection
- GRB 180316A: RATIR Optical Observations
- GRB 180316A: Enhanced Swift-XRT position
- GRB 180316A: LCO Cerro Tololo observations
- GROND observations of GRB 180316A
- GRB 180316A: Swift detection of a burst
- GRB 180314B: RATIR Optical Observations
- GRB 180314B: Zeiss-1000/CrAO optical upper limit
- GRB 180314B: Swift/UVOT Upper Limits
- GRB 180314B: Enhanced Swift-XRT position
- GRB 180314B: Swift detection of a burst
- Swift Trigger on MAXI J1820+070
- GRB 180314A: TAROT La Silla observatory optical observations
- GRB 180314A: LCO Siding Springs observations
- GRB 180314A: Swift/UVOT Detection
- GRB 180314A: REM optical/NIR observations
- GRB 180314A: MASTER-Net OT dtetction
- GRB 180314A: Enhanced Swift-XRT position
- GRB180314A: GROND detection of the afterglow
- GRB 180314A: Swift detection of a burst with an optical counterpart
- GRB 180311A: Swift/UVOT Upper Limits
- MAXI J1820+070: Swift/UVOT counterpart correction
- Swift detection of MAXI J1820+070
- GRB 180311A: Enhanced Swift-XRT position
- GRB 180311A: Swift detection of a burst
- GRB 180305A CALET Gamma-Ray Burst Monitor detection
- GRB 180305A: RATIR Optical Observations
- GRB 180305A: Swift/UVOT Upper Limits
- GRB 180305A: Mondy optical observations
- GRB 180305A: Swift-XRT afterglow detection
- GRB 180305A: RATIR Optical Afterglow Candidate
- GRB 180305A: Swift ToO observations
- GRB 180305A: Fermi-LAT detection
- GRB 180224A: Swift/UVOT Detection
- GRB 180224A: OASDG optical observations
- IPN Triangulation of GRB 180223A (long)
- GRB 180210A: Insight-HXMT/HE observation
- Swift Trigger 811686 is probably not an astrophysical source.
- GRB 180224A: AbAO optical observations
- GRB 180224A: RATIR Optical Observations
- GRB 180224A: Enhanced Swift-XRT position
- GRB 180224A: Swift detection of a burst with an optical counterpart