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"32495 results found.
- GRB 081025 BAT refined analysis
- Swift UVOT observations of GRB081025
- Swift UVOT observations of GRB081024B
- Konus-Wind observation of GRB 081025
- GRB 081025: Swift-XRT position
- GRB 081024B: Swift-XRT observations
- GRB 081024B: Fermi Gamma-ray Burst Monitor detection
- Swift UVOT observations of GRB 081024
- GRB 081024: Swift-XRT refined analysis
- GRB 081024, Swift-BAT refined analysis
- GRB 081024: Faulkes Telescope North optical observations
- GRB 081024: KAIT Optical Limits
- GRB 081024: Early Super-LOTIS Observations
- GRB 081024A: ROTSE-III Optical Limits
- GRB 081022, Swift-BAT refined analysis
- GRB 081016A: Swift-XRT refined analysis
- GRB 081012: Swift-XRT Refined Analysis
- Swift trigger 332287 is not a GRB
- GRB 081017, Swift-BAT refined analysis
- GRB 081017: REM early observations
- GRB 081016B, Swift-BAT refined analysis
- GRB 081016B: Swift/UVOT Upper Limits
- GRB 081011: Swift XRT refined analysis
- GRB 081016B: Swift-XRT Team refined Analysis
- GRB 081016B: ROTSE-III Optical Limits
- GRB 081016: Swift-XRT candidate afterglow detection
- Detection of flare star Algol in Swift-BAT slew data
- GRB 081012: GROND upper limits
- GRB 081008: Galaxy associated with z=1.967 absorber
- GRB 081012: Fermi GBM detection
- GRB 081007 and GRB 081007B: Fermi GBM detection
- GRB 080430: optical observations
- GRB 081008 optical upper limit
- GRB 081012: Observations from NOT
- GRB 081012: Swift/UVOT analysis of initial observations
- GRB 081012: Swift/XRT detection
- GRB 081012, Swift-BAT refined analysis
- GRB 081012: ROTSE-III Optical Limits
- Revised table for GRB 081011 UVOT detections
- GRB081011: UVOT detection of an optical afterglow
- GRB 081011: Swift/XRT detection
- GRB 081011, Swift-BAT refined analysis
- GRB 081008, SMARTS optical/IR afterglow observations
- GRB 081007: Radio Detection
- Konus-Wind observation of GRB 081001
- GRB 081007: Rapid PROMPT Detections
- GRB 081008, Swift-BAT refined analysis
- GRB 081008: VLT redshift confirmation
- GRB 081008: Swift-XRT Refined Analysis
- GRB081008: Swift/UVOT observations
- GRB 081008: Gemini-South Absorption Redshiftt
- GRB 081008: VLT/FORS2 spectroscopy
- GRB 081008: ROTSE-III Detection of Optical Counterpart
- GRB081007: Swift/UVOT Observations
- GRB 081007, SMARTS optical afterglow observations
- GRB 081007, Swift-BAT refined analysis
- GRB 081007: Early RAPTOR measurements of optical counterpart
- GRB 081007: Swift-XRT Team refined analysis
- GRB 081007: Gemini-south redshift
- GRB 081007, Faulkes Telescope North optical observations
- GRB 081007, SMARTS optical/IR afterglow observations
- GRB 081007: REM NIR and optical counterpart
- Fermi GBM detection of additional bursts from AXP 1E1547.0-5408
- INTEGRAL ToO observation of the AXP 1E 1547.0-5408
- AXP 1E 1547.0-5408: Swift/UVOT Upper Limits
- GRB 081003B: Swift-XRT upper limit
- 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
- Swift-BAT refined analysis of AXP 1E1547.0-5408 (Trigger 330353)
- GRB 080928: Fermi GBM detection
- AXP 1E1547.0-5408 (SGR 1550-5418): Fermi GBM detection
- SGR 1550-5418 = AXP 1E1547.0-5408 (Trigger 330353)
- Swift discovery of a new Soft Gamma Repeater SGR 1550-5418
- GRB 081001: Observations from OSN
- GRB 080925: Suzaku WAM observation of the prompt emission
- GRB 081001: Swift UVOT Observations
- GRB 081001: Swift-XRT position
- GRB081001: optical limit from ASH-Centurion
- GRB080928: redshift retraction
- GRB 080928: Watcher observations
- GRB 080928: VLT redshift
- GRB080928: Gemini-South Absorption Redshift
- GRB 080928: Swift-XRT refined analysis
- GRB 080928: Swift/UVOT observations
- GRB 080928, Swift-BAT final refined analysis
- GRB 080928: GROND DETECTION
- GRB 080928, Swift-BAT initial refined analysis
- GRB 080928A: ROTSE-III Confirmation of Optical Counterpart
- GRB080922, optical upper limit
- Swift-BAT trigger 325707 is not a GRB
- Swift trigger 325707: Swift/UVOT Upper Limits
- Swift trigger 325707: Swift-XRT upper limit
- GRB080916A: Suzaku WAM observation of the prompt emission
- GRB 080922: Swift/UVOT Upper Limits
- GRB080922: Swift-XRT upper limit
- GRB 080916C: Fermi GBM Spectral Analysis
- GRB 080919: Swift/UVOT Refined Analysis
- GRB 080919: Swift-XRT refined analysis