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"27327 results found.
- GRB 091020: Fermi GBM observation
- GRB 091026: Suzaku WAM observation of the prompt emission
- GRB 091026: GROND Upper Limits
- GRB 091026: Swift-BAT refined analysis
- Radio afterglow detection from GRB 091020
- GRB 091026: Swift/UVOT Upper Limits
- GRB 091026: Swift-XRT refined analysis
- GRB 091026: Enhanced Swift-XRT position
- Konus-Wind and Konus-RF observations of GRB 091024
- GRB 091026: Swift detection of a Gamma Ray Burst
- GRB091024 Swift/UVOT Upper Limits
- GRB 091024: Super-LOTIS early observations
- GRB 091024: Swift-BAT refined analysis
- GRB 091024: Fermi GBM Observations
- GRB 091024: Swift-XRT team refined analysis
- GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
- GRB 091024: GRAS004 optical observations
- GRB 091020: Swift-XRT refined analysis
- GRB 091018: Swift XRT refined analysis
- GRB091020 Swift/UVOT observations
- GRB 091020, Swift-BAT refined analysis
- 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
- Konus-RF observation of GRB 091018
- GRB 091018 : Faulkes Telescope South Observations
- GRB091018: Swift/UVOT observations
- GRB 091018: Swift-BAT refined analysis
- GRB 091018: Enhanced Swift-XRT position
- GRB 091018: ROTSE-III Detection of Optical Counterpart
- GRB 091015: Skynet/PROMPT Observations
- GRB 091018: Swift detection of a burst with optical afterglow
- GRB 091010: optical obsevation
- GRB 090726 R band observations
- GRB 091010: optical afterglow candidate rejection
- GRB 091010: Swift-XRT refined analysis
- GRB 091010: Suzaku WAM observation of the prompt emission
- 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: Fermi GBM observation
- GRB 091010: Faulkes Telescope North observations
- GRB 090531A: Skynet/PROMPT Observations
- GRB 090530A: Skynet/DSO Detections
- GRB 091010: Enhanced XRT position
- GRB 091010 optical upper limits
- Detection of a short GRB 090929A by RT-2 Experiment
- GRB 091010: GROND afterglow candidate
- GRB 091010: Swift/UVOT Upper Limits
- GRB 091010: Swift-XRT position
- GRB 090910: SuperAGILE Localization of a Long GRB
- GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
- GRB 090518: Skynet/PROMPT Observations
- Short-Duration GRB 090621: Skynet/Dolomiti Observations
- GRB 090904A: afterglow confirmation
- GRB 090812: Skynet/PROMPT and GORT Observations
- GRB 091003A: Suzaku WAM observation of the prompt emission
- GRB 090926B: Skynet/PROMPT Observations
- GRB 091003: WHT ACAM observations
- GRB 090929B: Suzaku WAM observation of the prompt emission
- GRB 090929A: Suzaku WAM observation of the prompt emission
- GRB 091003: Swift/UVOT Detection of an Optical Afterglow
- GRB 091003: Skynet/DSO Observations
- GRB 091003: UVOT-enhanced XRT position
- GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
- GRB 091003A: Fermi LAT detection
- GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
- GRB 091003A: Fermi GBM detection
- GRB 090926A: Skynet/PROMPT Observations of Post-Peak Fading
- GRB 090929A, Swift-BAT refined analysis
- GRB 090929B, Swift-BAT refined analysis
- Trigger 371210: Swift/BAT Triggered on IGR J17511-3057
- GRB 090929A: Swift-XRT non-detection
- Konus-Wind observation of GRB 090929B
- GRB 090929B: Swift-XRT refined analysis
- GRB 090929B: Gemini-N upper limits
- GRB 090929B: Skynet/DSO Observations
- GRB 090929B: Swift/UVOT Observations
- GRB 090929B: RAPTOR Discovery of Optical Counterpart
- GRB 090929A BAT location of the Fermi GBM burst
- Correction: GRB 090929B: Enhanced Swift-XRT position
- GRB 090929: Enhanced Swift-XRT position
- GRB 090929B: Swift detection of a burst
- GRB 090929A: Fermi GBM detection
- GRB090926A: Swift-XRT refined analysis
- GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
- GRB 090927: Zadko Telescope observations
- GRB 090927, Swift-BAT refined analysis of the possibly short burst
- Swift/UVOT observations of GRB 090927
- GRB 090926A: Skynet/PROMPT Continued Observations
- GRB 090927: Swift XRT refined analysis
- GRB 090926A: Suzaku WAM observation of the prompt emission
- GRB 090927: Enhanced Swift-XRT position
- GRB090926B: Swift/UVOT Upper Limits
- GRB090926A: Swift/UVOT observations
- GRB 090927: Swift/UVOT detection of an optical afterglow
- GRB 090927: Swift detection of a short burst
- GRB 090926B: optical object in error circle