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"19803 results found.
- SGR 0501+4516: optical observations in August
- SGR 0623-0006 or GRB 081101: Swift-BAT/-XRT refined analysis
- GRB 081024B: BTA deep optical observations
- GRB 081024B: new Swift-XRT observations
- Radio observation of GRB 080229b with ATCA
- GRB 081024B: VLA radio observation
- GRB 081029: UVOT Detection of the Optical Afterglow
- GRB 081029: Enhanced Swift-XRT position
- GRB 081028: GROND Confirmation of the Optical/NIR Afterglow
- GRB 081029: REM observations
- Radio observation of GRB 080303 with ATCA
- Radio observation of GRB 080411 with ATCA
- GRB 081029: GROND Detection of the Optical/NIR Afterglow
- GRB 081028B: Fermi GBM detection
- Swift UVOT observations of GRB081028
- GRB 081028: Enhanced Swift-XRT position
- GRB 081028: TAROT Calern observatory optical observations
- GRB 081028: optical observations at the NOT
- GRB 081028: GROND Detection of the Optical/NIR Afterglow Candidate
- Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow (Corrected)
- Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow
- GRB 081028: Swift detection of a burst
- GRB 081024: No radio detection with the VLA
- GRB081025: RTT150 optical observations
- GRB081024B: P200 Observations
- GRB 081024B: Swift-XRT further observations
- Swift UVOT observations of GRB081024B
- GRB 081025: Swift-XRT position
- GRB 081024B: Swift-XRT observations
- GRB 081025: Burst detection from Swift-BAT slew data
- GRB 081024: Enhanced Swift-XRT position
- GRB 081024: Faulkes Telescope North optical observations
- GRB 081024A: ROTSE-III Optical Limits
- GRB 081024: Swift detection of a burst
- GRB 081016A: Swift-XRT refined analysis
- Swift detection of a possible burst (trigger 332287)
- GRB 081017: REM early observations
- GRB 081011: Swift XRT refined analysis
- GRB 081016B: Enhanced Swift-XRT position
- GRB 081016B: ROTSE-III Optical Limits
- GRB 081016B: Swift detection of a burst
- GRB 081011: Enhanced Swift-XRT position
- Swift detection of flare on CC Eri
- Trigger 331721 Due to Swift startracker loss-of-lock
- Detection of flare star Algol in Swift-BAT slew data
- GRB 081012: GROND upper limits
- GRB 081008: Galaxy associated with z=1.967 absorber
- Swift-BAT triggered on the flare star Algol
- GRB 080430: optical observations
- GRB 081012: Observations from NOT
- GRB 081012: Swift/XRT detection
- GRB 081012, Swift-BAT refined analysis
- GRB081011: UVOT detection of an optical afterglow
- GRB 081011: Swift/XRT detection
- GRB 081008, SMARTS optical/IR afterglow observations
- GRB 081011: Swift detection of a burst
- GRB 081007: Radio Detection
- GRB081008: Swift/UVOT observations
- GRB 081008: Enhanced Swift-XRT position
- GRB 081008: Swift detection of a burst with optical afterglow
- GRB081007: Swift/UVOT Observations
- GRB 081007, SMARTS optical afterglow observations
- GRB 081007: Early RAPTOR measurements of optical counterpart
- GRB 081007: Enhanced Swift-XRT position
- GRB 081007, Faulkes Telescope North optical observations
- GRB 081007: REM NIR and optical counterpart
- GRB 081007: Swift detection of a burst with optical afterglow
- GRB081003C: GLAST Burst Monitor detection
- GRB 081003B: TAROT Calern observatory optical observations
- AXP 1E 1547.0-5408: Swift/UVOT Upper Limits
- GRB 081003A: OSN optical observations
- GRB 081001: Further observations from OSN
- AXP 1E1547.0-5408: Swift-XRT Team refined analysis
- GRB 081003A: Swift-XRT Team position and analysis
- SGR 1550-5418 = AXP 1E1547.0-5408 (Trigger 330353)
- Trigger 330353: Swift detection of a Galactic short soft burst
- GRB 081001: Observations from OSN
- GRB 081001: Swift UVOT Observations
- GRB 081001: Swift-XRT position
- GRB 080928: Watcher observations
- GRB 080928: GROND DETECTION
- GRB 080928: Enhanced Swift-XRT position
- GRB 080928: Swift detection of a burst with an optical counterpart
- GRB080922, optical upper limit
- Swift trigger 325707: Swift/UVOT Upper Limits
- Swift trigger 325707: Swift-XRT upper limit
- Swift detection of a possible GRB (trigger 325707)
- GRB 080922: Swift/UVOT Upper Limits
- Trigger 324561: IGR J08408-4503 detected by Swift
- GRB 080916C: Fermi GBM Spectral Analysis
- GRB 080919: Swift-XRT refined analysis
- GRB 080916C: IRSF/SIRUS NIR Observation
- GRB 080916C: GROND Confirmation of the Optical Afterglow
- GRB 080916C: GROND Confirmation of the Optical Afterglow
- GRB 080919: REM NIR observations
- GRB 080919: Swift detection of a short burst
- GRB 080915A: GROND upper limits
- GRB 080916A: GROND lightcurve
- GRB 080916C: Swift UVOT Refined Analysis
- GRB 080916C: Swift XRT refined analysis