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"19608 results found.
- GRB 090927: Zadko Telescope observations
- GRB 090927, Swift-BAT refined analysis of the possibly short burst
- 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 090927: Swift/UVOT detection of an optical afterglow
- GRB 090927: Swift detection of a short burst
- GRB 090926B: MAXI GSC detection
- GRB 090926B: Swift XRT refined analysis
- GRB 090926B: Swift-BAT refined analysis
- GRB 090926A: Swift/UVOT detection of an optical afterglow
- GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
- GRB090926A: UVOT-enhanced XRT position
- GRB 090926B: Swift detection of a burst
- GRB 090926: Fermi LAT detection
- GRB090904B : IRSF NIR upper limit
- Swift returns to normal operations
- GRB 090715B: Skynet/PROMPT Detections
- GRB 090916: Swift-XRT upper limit
- GRB 090807: Skynet/DSO Observations
- Swift-BAT temporarily off-line for a few days
- Short-Duration GRB 090916: Skynet/PROMPT Observations
- GRB 090912: optical observation
- GRB 090915: Swift/UVOT detection of an optical afterglow candidate
- GRB 090916, Swift-BAT refined analysis
- GRB 090915: Swift-XRT detection of a fading X-ray counterpart
- GRB 090916: Swift detection of a short burst
- GRB 090915 Swift-BAT detection of a burst in ground analysis
- GRB 090827: Confirmation of the X-ray afterglow
- GRB 090912: Swift-XRT refined analysis
- GRB 090912, Swift-BAT refined analysis
- GRB 090912: Swift/UVOT Upper Limits
- 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 090904A: Swift/UVOT Refined Analysis
- GRB 090904B: Swift/UVOT Refined Analysis
- GRB 090904B: Fermi GBM detection
- GRB 090904A: Swift-XRT refined analysis
- GRB 090904B: Swift XRT Refined Analysis
- GRB 090904B: MOA-II Optical observation
- GRB 090904A: Enhanced Swift XRT position
- GRB 090904B: Swift-BAT refined analysis
- GRB 090904A: Swift-BAT refined analysis
- GRB 090904B: Enhanced Swift-XRT position
- GRB090904A: Correction to enhanced XRT position
- GRB 090904A: Enhanced Swift-XRT position
- GRB090904B: REM observations
- GRB 090904B: Swift detection of a burst
- GRB 090904A: ROTSE-III Optical Limits
- GRB 090904: Swift detection of a burst
- GRB 090902B: Swift/UVOT refined analysis
- GRB090902B: Swift XRT refined analysis
- GRB 090902B: Faulkes Telescope North observations
- GRB 090902B: GROND NIR Afterglow Observations
- GRB 090902B: Gemini-N absorption redshift
- GRB 090902B: Enhanced Swift-XRT position
- GRB 090902B: Optical afterglow candidate
- GRB090902B: Swift/UVOT observations
- GRB 090902B: Swift/XRT Afterglow Candidate
- GRB 090902B: Fermi LAT detection
- GRB 090831C BAT refined analysis
- GRB 090831C: GROND upper limits
- Swift Trigger 361477, called GRB090831B, is probably not real.
- GRB090831C: Swift/UVOT upper limits
- GRB 090831C: Swift XRT Refined Analysis
- GRB 090831C: Enhanced Swift-XRT position
- GRB 090831C: Swift detection of a burst
- GRB 090831B, RIMOTS optical upper limits
- GRB 090831B: Swift detection of a possible burst
- GRB 090827: Swift XRT and UVOT observations
- GRB 090827 Burst discovered in BAT ground analysis
- GRB 090823: Swift XRT possible detection of the X-ray afterglow
- GRB 090823: Confirmation of Swift-BAT position by BAT Slew Survey
- GRB 090823 Correction to BAT position
- GRB 090817: No host galaxy, no supernova
- Konus-Wind observations of GRB 090823
- GRB 090823 Long burst with IPN triangulation and BAT position
- GRB 090817: Swift/UVOT Observations of a Possible Late-Time Brightening
- GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
- GRB 090817: Liverpool Telescope Observations
- GRB 090817: Confirmation of the X-ray afterglow
- GRB 090815C: Swift refined analysis
- GRB 090817: Swift/UVOT Upper Limits
- GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis
- GRB 090817: Swift-XRT observations
- GRB 090813: Suzaku WAM observation of the prompt emission
- GRB 090812: Suzaku WAM observation of the prompt emission
- GRB 090813: CrAO optical obsevations
- GRB 090814B: Confirmation of the X-ray afterglow
- GRB 090814B: I-band observations from 1.23m CAHA telescope
- GRB 090814B: Swift/UVOT Upper Limits
- GRB 090814B: Liverpool Telescope Observations
- GRB 090814B: Swift-XRT detection of a possible afterglow.
- GRB 090814A: Swift/UVOT Observations
- GRB 090814A: Swift-XRT Team Refined Analysis