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"27297 results found.
- GRB 091024: optical observations
- GRB 091031: Fermi GBM detection
- GRB 091024: Fermi LAT upper limits
- GRB 090920: Skynet/DSO Detection
- GRB091029: Swift/UVOT observations
- GRB 091029: Swift XRT refined analysis
- GRB 091029: Swift-BAT refined analysis
- GRB 091029: Enhanced Swift-XRT position
- GRB 091029: Skynet/PROMPT Observations of Peak and Fading
- GRB 091029: GROND Detection of the Optical/NIR Afterglow
- GRB 091029: Swift detection of a burst with an optical counterpart
- A mistake in testing a new function in Swift
- GRB 091020: Fermi GBM observation
- GRB 091026: Suzaku WAM observation of the prompt emission
- GRB 091026: GROND Upper Limits
- GRB 091020: Late TLS detection
- GRB 091026: Swift-BAT refined analysis
- Radio afterglow detection from GRB 091020
- GRB 091026: Swift/UVOT Upper Limits
- GRB 091024: Burst was outside the Swift-BAT FOV after T0(BAT)+460sec
- GRB 091026: Swift-XRT refined analysis
- GRB 091026: Enhanced Swift-XRT position
- Konus-Wind and Konus-RF observations of GRB 091024
- GRB 091026: Updated Swift-XRT position
- GRB 091026: Swift detection of a Gamma Ray Burst
- Swift-BAT Triggers 373776-373778 are not real
- GRB091024 Swift/UVOT Upper Limits
- GRB 091024: TLS Upper Limit
- GRB 091020: Early TLS Multicolor detections, red afterglow
- GRB 091024: KAIT optical afterglow observations
- GRB 091024: Swift-BAT refined analysis
- Swift-BAT Triggers 373679-373684 are not real
- GRB 091024: Fermi GBM Observations
- GRB 091024: Swift-XRT team refined analysis
- Swift-BAT trigger 373691 is a galactic bulge transient
- GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
- GRB 091024: Faulkes Telescope North Afterglow Candidate
- GRB 091024: Swift detection of a burst
- 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
- GRB 091018: VLT/X-shooter spectra
- 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 091018: Swift detection of a burst with optical afterglow
- GRB 090726 R band observations
- GRB 091010: Swift-XRT refined analysis
- Radio observation of GRB090927 with ATCA
- GRB 091010: Fermi GBM observation
- GRB 090531A: Skynet/PROMPT Observations
- GRB 090530A: Skynet/DSO Detections
- GRB 091010: RXTE detection
- GRB 091010: Enhanced XRT position
- 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 090518: Skynet/PROMPT Observations
- Short-Duration GRB 090621: Skynet/Dolomiti Observations
- GRB 090812: Skynet/PROMPT and GORT Observations
- GRB 091003: Lick observations and possible SDSS host galaxy
- GRB 090926B: Skynet/PROMPT Observations
- GRB 091003: WHT ACAM observations
- GRB 090929B: Suzaku WAM observation of the prompt emission
- GRB 091003: Swift-XRT confirmation of fading afterglow
- 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 091003: Swift XRT analysis
- GRB 091003A: Fermi LAT detection
- GRB 091003A: Fermi GBM detection
- GRB 090929A: Swift/UVOT Observations
- 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 090929A
- Konus-Wind observation of GRB 090929B
- GRB 090927: Fermi GBM observation
- GRB 090929B: Swift-XRT refined analysis
- GRB 090929B: Skynet/DSO Observations
- GRB 090929B: Swift/UVOT Observations
- Konus-RF observation of GRB 090929A
- 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