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"17850 results found.
- GRB 091029: Swift detection of a burst with an optical counterpart
- GRB 091026: Suzaku WAM observation of the prompt emission
- GRB 091026: GROND Upper Limits
- Radio afterglow detection from GRB 091020
- GRB 091026: Swift/UVOT Upper Limits
- GRB 091026: Enhanced Swift-XRT position
- GRB 091026: Swift detection of a Gamma Ray Burst
- GRB091024 Swift/UVOT Upper Limits
- GRB 091024: Super-LOTIS early observations
- GRB091024: VRcIc Afterglow Observations
- GRB 091024: Fermi GBM Observations
- GRB 091024: Swift-XRT team refined analysis
- GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
- GRB 091024: GRAS004 optical observations
- GRB091020 Swift/UVOT observations
- GRB 091020: Enhanced Swift-XRT position
- GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
- GRB 091020: Swift detection of a burst with an optical afterglow
- GRB 091018: Skynet/PROMPT Observations of Fading
- GRB 091018 : Faulkes Telescope South Observations
- GRB091018: Swift/UVOT observations
- GRB 091018: Enhanced Swift-XRT position
- GRB 091018: Swift detection of a burst with optical afterglow
- GRB 091010: optical obsevation
- GRB 091010: Swift-XRT refined analysis
- GRB 091010: AGILE-MCAL measurement and GRID upper limit
- Radio observation of GRB090927 with ATCA
- Radio observation of GRB090926a with ATCA
- Radio observation of GRB080916c with ATCA
- GRB 091010: Enhanced XRT position
- GRB 091010 optical upper limits
- GRB 091010: GROND afterglow candidate
- GRB 091010: Swift/UVOT Upper Limits
- GRB 090904A: afterglow confirmation
- GRB 090812: Skynet/PROMPT and GORT Observations
- GRB 091003: WHT ACAM observations
- GRB 091003: Swift/UVOT Detection of an Optical Afterglow
- GRB 091003: UVOT-enhanced XRT position
- GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
- GRB 091003A: Fermi LAT detection
- GRB 090929B, Swift-BAT refined analysis
- Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
- GRB 090929A: Swift-XRT non-detection
- GRB 090929B: Gemini-N upper limits
- GRB 090929B: Swift/UVOT Observations
- GRB 090929B: RAPTOR Discovery of Optical Counterpart
- Correction: GRB 090929B: Enhanced Swift-XRT position
- GRB 090929: Enhanced Swift-XRT position
- GRB 090929B: Swift detection of a burst
- GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
- GRB 090927: Zadko Telescope observations
- Swift/UVOT observations of GRB 090927
- GRB 090927: Swift XRT refined analysis
- GRB 090927: Enhanced Swift-XRT position
- GRB090926B: Swift/UVOT Upper Limits
- GRB090926A: Swift/UVOT observations
- GRB 090926B: optical object in error circle
- GRB 090926B: NOT optical observation
- GRB 090926B: Swift XRT refined analysis
- GRB 090926A: Swift/UVOT detection of an optical afterglow
- GRB090926A: UVOT-enhanced XRT position
- GRB 090926B: Swift detection of a burst
- GRB 090926: Fermi LAT detection
- GRB 090916: Swift-XRT upper limit
- GRB 090915: GROND upper limits
- GRB 090915: SARA detection of afterglow candidate
- GRB 090912: optical observation
- GRB 090915: Swift/UVOT detection of an optical afterglow candidate
- GRB 090915: Swift-XRT detection of a fading X-ray counterpart
- GRB 090915 Swift-BAT detection of a burst in ground analysis
- GRB 090827: Confirmation of the X-ray afterglow
- GRB 090912: Swift/UVOT Upper Limits
- GRB 090912 optical upper limit
- GRB 090912: Enhanced Swift-XRT position
- GRB 090912: Swift detection of a burst
- GRB 090814A: Skynet/DSO & GORT Observations
- GRB 090823: Swift XRT confirmation of the X-ray afterglow
- GRB 090904B: GROND detection of the optical afterglow
- GRB 090904B: Swift/UVOT Refined Analysis
- GRB 090902B: VLA radio detection
- GRB 090904B: Enhanced Swift-XRT position
- GRB 090904A: Enhanced Swift-XRT position
- GRB 090904A: NOT observations
- GRB090904B: REM observations
- GRB 090904B: Swift detection of a burst
- GRB 090904: Swift detection of a burst
- GRB 090902B: Swift/UVOT refined analysis
- GRB 090902B: GROND NIR Afterglow Observations
- GRB 090902B: Enhanced Swift-XRT position
- GRB090902B: Swift/UVOT observations
- GRB 090902B: Swift/XRT Afterglow Candidate
- GRB 090902B: Fermi LAT detection
- GRB 090831C: GROND upper limits
- Konus-Wind observations of GRB 090831A
- Swift Trigger 361477, called GRB090831B, is probably not real.
- GRB090831C: Swift/UVOT upper limits
- GRB 090831B: MITSuME optical upper limits
- GRB 090829B: Fermi GBM Detection
- GRB 090831C: Enhanced Swift-XRT position
- GRB 090831C: Swift detection of a burst