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 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
- Konus-Wind observation of GRB 120602A
- IPN Triangulation of GRB 120602A (long/very bright)
- GRB 120614A: MAXI/GSC detection of a burst
- GRB 120612A: optical observations
- GRB 120612A: Swift/UVOT observations
- GRB 120612A: Swift-XRT refined Analysis
- GRB 120612A: Swift-BAT refined analysis
- GRB 120612A: Enhanced Swift-XRT position
- GRB 120612A: BOOTES-3 optical upper limit
- GRB 120612A: Swift detection of a burst
- GRB 120603A: Suzaku WAM observation of the prompt emission
- GBM triggers 120604.526 & 120604.399 were not GRBs
- Konus-Wind observation of GRB 120603A
- IPN Triangulation of short GRB 120603A
- Fermi GBM trigger 120602.539 is not a GRB
- Konus-Wind observation of GRB 120528B
- GRB 120519A: Suzaku WAM observation of the prompt emission
- GRB 120528C: MAXI/GSC detection
- GRB 120521C redshift estimate
- Fermi Gamma-ray Burst Monitor trigger 120527.573 is not a GRB
- GRB 120528B: MAXI/GSC detection
- GRB 120512A: Suzaku WAM observation of the prompt emission
- GRB 120521C: EVLA Localization of Afterglow
- GRB 120521C: EVLA 22 GHz Detection
- GRB120521B: SSO 2.3m upper limits
- Konus-Wind observation of GRB 120522A
- IPN triangulation of GRB 120522A (long/intense)
- GRB 120521B: Fermi GBM observation
- GRB 120521A: ATCA 34GHz upper limit
- GRB 120521C: Early Tautenburg limits
- GRB 120521C: EVLA 22 GHz Upper Limit
- GRB 120521A: GROND Upper limits
- GRB 120521C: Swift-XRT refined Analysis
- GRB 120521C: Swift-BAT refined analysis
- GRB 120521C: Keck Observations
- GRB 120521C: Swift/UVOT Upper Limits
- GRB 120521B: Swift/UVOT Upper Limits
- GRB 120521C: MASTER optical limit
- GRB 120521B: GROND Upper limits
- GRB 120521A: XRT light curve (Correction to GCN 13326)
- GRB 120521A: Swift-XRT refined Analysis
- GRB 120521C: PAIRITEL NIR Upper Limits
- GRB 120521C: Enhanced Swift-XRT position
- GRB 120521C: BOOTES-1 optical observations
- GRB 120521C: WHT optical observations
- GRB 120521C - NOT optical limits
- GRB120521C: Liverpool Telescope observations
- GRB 120521C: TAROT Calern observatory optical observations
- GRB 120521C: Swift detection of a burst
- GRB 120521B: Swift-BAT refined analysis
- GRB 120521B: Swift-XRT refined Analysis
- Konus-Wind observation of GRB 120519A
- Swift starts a new program to find fainter transients
- IPN Triangulation of GRB 120519A (short/hard)
- GRB 120521A: Swift/UVOT Upper Limits
- GRB 120521B: Enhanced Swift-XRT position
- GRB 120521A: Swift-BAT refined analysis