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"- GRB 120711A: INTEGRAL/SPI observations
- GRB120714A: UVOT non-detection
- GRB 120714A: Swift-XRT observations
- GRB120711B: MITSuME Ishigakijima upper limits
- GRB 120714A: Swift detection of a burst
- GRB 120711A: ATCA 34GHz further observations (upper limit)
- IPN Triangulation of GRB 120709A
- GRB 120712A: Swift/UVOT Detection
- GRB 120712A: VLT/Xshooter redshift
- GRB 120712A: Swift-XRT refined Analysis
- GRB 120712A Gemini-S redshift
- GRB 120712A: GROND Detection of the Optical/NIR Afterglow Candidate and photo-z
- GRB 120712A: Enhanced Swift-XRT position
- GRB 120712A: Swift-BAT refined analysis
- GRB 120712A: Swift detection of a burst with optical afterglow
- GRB 120711B: Swift-XRT refined Analysis
- GRB 120711A: Fermi LAT Detection
- GRB 120711A: ATCA 34GHz upper limit
- GRB 120711B: Swift-BAT refined analysis
- GRB 120711B: Swift/UVOT Upper Limits
- GRB 120711A: Swift/UVOT Observations
- GRB 120709A: Swift/UVOT Observations
- Konus-Wind observation of GRB 120711A
- GRB 120711A: Fermi LAT detection
- GRB 120711A: MASTER early OT detection
- GRB 120711A: Swift-XRT observations
- GRB 120711A Gemini-S likely redshift
- Konus-Wind observation of GRB 120709A
- GRB 120711A: REM NIR early time detection
- GRB 120711A: GROND photometric redshift
- GRB 120711A: Fermi GBM observation
- GRB 120711A: MAXI/GSC detection
- GRB 120711A: a possible X-ray transient
- GRB 120711A: an bright long GRB detected with INTEGRAL
- Continued Skynet/PROMPT observations of GRB120711A
- GRB 120711A: ROTSE-III confirm of Optical Counterpart
- Swift detection of GRB 120711B or a new Galactic transient
- Skynet/PROMPT Observations of GRB120711A
- GRB 120709A: Fermi GBM detection
- GRB 120709A: Swift-XRT observations
- GRB 120709A: Matched filter analysis of Fermi-LAT data
- GRB 120709A: optical afterglow limits
- Konus-Wind observation of GRB 120707A
- IPN Triangulation of GRB 120707A
- GRB 120709A: Fermi-LAT Detection
- GRB 120707A: Fermi GBM Detection of a Bright Burst
- GRB 120624B: mm detection at PdBI
- GRB 120703A: SMARTS optical/IR observations
- GBM triggers 120705.153 & 120705.322 were not GRBs
- GRB 120703A: Swift/UVOT Detection
- GRB 120703A: Fermi GBM detection
- GRB 120703A: Swift-XRT refined Analysis
- GRB 120703A: Enhanced Swift-XRT position
- GRB 120703A: Swift-BAT refined analysis
- GRB 120624B Suzaku WAM observation of the prompt emission
- Konus-Wind observation of GRB 120703A
- GRB 120703A: NOT optical observation
- GRB 120701A: Swift/UVOT Detection
- GRB 120701A: GROND detection of the afterglow
- GRB 120703A: Swift detection of a bright burst with an optical afterglow
- Swift Trigger 525554 is noise
- GRB 120701A: Swift-XRT afterglow detection and analysis
- GRB 120630A: Swift-BAT/-XRT/-UVOT refined analysis
- GRB 120701A: Swift-BAT refined analysis
- GRB 120630A: NOT optical source within the XRT error circle
- Swift Trigger 525554 is probably not a GRB
- GRB120624B: Chandra observations and afterglow detection
- Fermi Gamma-ray Burst Monitor trigger 120628.973 is not a GRB
- GRB 120624B Further Swift-XRT analysis
- GRB 120624B: Swift/UVOT Upper Limits
- Watcher follow-up observations of IGR J17062-6143 (Swift trigger 525148)
- GRB 120624B: Further analysis of the HAWKI observations
- GRB 120624B: Swift-XRT observations
- GRB 120624B: GROND upper limits
- XRF 120626B: MAXI/GSC detection
- GRB 120624B: NIR counterpart candidate from HAWKI
- Skynet/PROMPT observations of IGR J17062-6143 (Swift trigger 525148)
- GRB 120624B: Discussion of Fermi and Swift measurements and future Swift observations
- Swift detection of Ginga 0834-430
- GRB 120624B: NOT optical upper limit
- Swift detection of IGR J17062-6143
- GRB 120624B: optical observations
- GRB 120624B, Swift-BAT refined analysis
- GRB 120624B: Fermi GBM fluence and peak photon flux correction
- Konus-Wind observation of GRB 120624B
- GRB 120624B: Swift detection of a burst
- GRB 120624A: Fermi GBM observation
- GRB 120624B: Fermi-LAT Detection
- Konus-Wind observation of GRB 120624A
- GRB 120624B: Fermi GBM detection
- IPN Triangulation of GRB 120624A (short/intense)
- Swift Trigger 524949: Noise fluctuation near a galaxy
- GRB 120622A: MAXI/GSC detection
- Swift trigger 524642 / SwJ1910.2-0546
- GRB 120602A: Suzaku WAM observation of the prompt emission
- Konus-Wind observation of GRB 120617A
- IPN Triangulation of GRB 120617A (short/intense)
- Swift Trigger 524642 is Swift J1910.2-0546
- Trigger 524584: Swift detection of Algol
- Swift triggers (#524542) on a Galactic source