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"- GRB121202A: Swift/UVOT Observations
- GRB 121202A: TAROT Calern observatory optical observations
- GRB 121202A: Swift detection of a burst
- GRB 121201A: GROND afterglow observations and photometric redshift
- GRB 121201A: Swift/UVOT Detection
- GRB 121201A: Swift-XRT refined Analysis
- GRB 121201A: Swift-BAT refined analysis
- GRB 121201A: Enhanced Swift-XRT position
- GRB 121201A: BOOTES-4 optical observations
- GRB 121201A: a GRB with an optical counterpart
- GRB 121128A: optical observation in Mondy observatory
- GRB 121128A: MITSuME Akeno Optical upper limits
- Konus-Wind observation of GRB 121127A
- IPN Triangulation of GRB 121127A (short/hard)
- GRB 121125A: optical upper limit
- GRB 121128A: optical observation in Mondy observatory
- GRB 121128A: WSRT radio observation
- GRB 121128A: Swift/UVOT Detection
- GRB 121128A: Swift-XRT refined Analysis
- GRB 121128A: Enhanced Swift-XRT position
- GRB 121122A: Fermi GBM observation
- GRB 121128A: RAPTOR Detection During Gamma-Ray Emitting Interval
- GRB 121128A: Fermi GBM observation
- GRB 121128A, Swift-BAT refined analysis
- Konus-Wind observation of GRB 121128A
- GRB 121128A - Gemini North redshift
- GRB 121128A: FTN optical afterglow confirmation
- GRB 121128A: Swift detection of a burst with an optical counterpart
- GRB 121123A: Suzaku WAM observation of the prompt emission
- Konus-Wind observation of GRB 121122A
- GRB 121117A: Terskol obseravtions
- GRB 121123A: Swift/UVOT Observations
- GRB 121125A: Swift/UVOT Detection
- IPN Triangulation of GRB 121122A (long/intense)
- GRB 121118B: Suzaku WAM observation of the prompt emission
- GRB 121125A: Swift-XRT refined Analysis
- GRB 121125A: Enhanced Swift-XRT position
- GRB 121125A: Fermi GBM Observation
- GRB 121125A: Swift-BAT refined analysis
- GRB 121125A: LOAO Observation
- GRB 121125A: MASTER-NET optical observations
- GRB 121125A: Swift detection of a burst with optical counterpart
- GRB 121123A: GROND observations
- GRB 121123A: Enhanced Swift-XRT position
- GRB 121123A: Swift-BAT refined analysis
- GRB 121123A: Swift-XRT refined Analysis
- GRB 121123A: optical observations
- GRB 121123A: BOOTES-4 and IAC80 optical observations
- GRB 121123A: NOT optical observations
- GRB 121123A: Fermi GBM observation
- GRB 121123A: MASTER-NET optical limit
- GRB 121123A: GMG optical observation
- GRB 121123A: Swift detection of a burst with optical counterpart
- GRB 121108A: optical upper limit
- GRB 121117A: Optical observations
- Konus-Wind observation of GRB 121118B
- GRB 121117A: optical upper limit
- IPN Triangulation of GRB 121118B (long/intense)
- GRB 121117A: GROND confirmation of the UVOT afterglow candidate
- IPN Triangulation of GRB 121118A
- Swift-BAT trigger 538575 is not astrophysical
- GRB 121117A: Swift/UVOT Observations
- GRB 121117A: Swift-XRT refined Analysis
- GRB 121117A: MASTER prompt optical limit
- GRB 121117A, Swift-BAT refined analysis
- GRB 121117A: ROTSE-III Optical Limits
- GRB 121117A: BOOTES-3 early optical upper limit
- GRB 121117A: Swift detection of a burst
- Swift trigger 538575: Magellan Observations
- Fermi GBM trigger 121115.186 is not a GRB
- Trigger 538084: Swift detection of XTE J1739-302
- GRB 121108A: Swift-XRT refined Analysis
- GRB 121108A: Swift/UVOT Upper Limits
- GRB 121108A, Swift-BAT refined analysis
- GRB 121108A: Xinglong TNT upper limit
- GRB 121108A: Enhanced Swift-XRT position
- GRB 121108A : Lulin/TRIPOL2 Optical Limits
- GRB 121108A: Optical observations
- GRB 121108A: MITSuME Ishigakijima upper limits
- GRB 121108A: Weihai observatory optical observations
- GRB 121108A: MASTER early prompt optical limit
- GRB 121108A: TAROT Calern observatory optical observations
- GRB 121108A: Swift detection of a burst
- GRB 121031A: Fermi GBM detection
- GRB 121028A: Swift/UVOT Upper Limits
- GRB 121031A, Early peak observed with Swift-BAT
- GRB 121102A: Swift/UVOT Upper Limits
- GRB 121031A: Swift/UVOT Upper Limits
- GRB 121031A: Swift-XRT refined Analysis
- GRB 121102A: Enhanced Swift-XRT position
- GRB 121031A: Enhanced Swift-XRT position
- GRB 121102A: Swift-XRT refined Analysis
- GRB 121102A: Swift-BAT refined analysis
- GRB 121025A: Confirmation of the X-ray afterglow
- GRB 121029A Suzaku WAM observation of the prompt emission
- GRB 121102A : a long GRB detected by INTEGRAL
- GRB 121102A: Swift detection of a burst
- GRB 121027A: sub-mm upper limit
- GRB 121031A: Swift-BAT refined analysis
- GRB 121031A: Prompt enhanced Swift-XRT position