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 131209A: Fermi-LAT detection of a burst
- GRB131202A : GROND observations
- GRB131205A : GROND Observations
- GRB 131205A: Swift-BAT refined analysis
- GRB 131205A: Swift-XRT refined Analysis
- Swift Trigger 580319 is not a GRB
- GRB 131205A: Swift/UVOT Upper Limits
- GRB 131205A: Enhanced Swift-XRT position
- GRB 131205A: Zadko observatory - Gingin optical observations
- GRB 131205A: Swift detection of a burst
- GRB 131127B: Bassano Bresciano Observatory,archival confirmation of iPTF13ecv
- GRB 131202A: theoretical estimation of the redshift
- GRB 131127B: archival confirmation of iPTF13ecv as a CV
- GRB 131127B: rejection of optical counterpart candidates
- GRB 131126A: Fermi GBM observation
- GRB 131126A: iPTF upper limits on the afterglow of a short GRB
- GRB 090530: X-shooter redshift
- GRB 131127A: optically dark burst
- GRB 131202A, Swift-BAT refined analysis
- GRB 131202A: Swift/UVOT Upper Limits
- GRB 131202A: Swift-XRT refined Analysis
- GRB 131202A: RATIR Optical and NIR Observations
- GRB 131202A: Fermi GBM Detection
- GRB 131202A: Enhanced Swift-XRT position
- GRB 131202A: Bassano Bresciano Observatory optical upper limit
- GRB 131202A: Tautenburg observations
- GRB 131202A : XMM-Newton planned observation
- GRB 060614: theoretical derivation of the redshift and need for deeper search of the host galaxy
- GRB 131202A: Swift detection of a burst
- GRB 131127B: Bassano Bresciano Observatory optical observations of iPTF13ecv
- GRB 131122A: Swift-XRT Further Observation
- GRB 131128A: Bassano Bresciano Observatory optical upper limit
- GRB 131127A: RATIR Rejection of High-z Candidate
- GRB 131128A; Fermi GBM observation
- GRB 131125A: MASTER-Net very early optical observations
- GRB 131125A: iPTF upper limits on the afterglow of a short GRB
- Konus-Wind observation of GRB 131126A
- IPN Triangulation of GRB 131126A (short/hard)
- Konus-Wind observation of GRB 131125A
- GRB 131127A: CQUEAN riz Observation
- GRB 131128A: GROND observations of the afterglow
- IPN Triangulation of GRB 131125A (short/hard)
- GRB 131128A: Swift/UVOT Detection
- GRB 131128A: AROMA-N Optical Observation
- GRB 131127B: Bassano Bresciano Observatory optical observations
- GRB 131128A: Swift-XRT refined Analysis
- GRB 131128A: Kanata/HOWPol optical observation
- GRB 131128A: T100 observations
- GRB 131128A: Swift-BAT refined analysis
- GRB 131128A: Enhanced Swift-XRT position
- GRB 131128A: Nanshan afterglow confirmation
- GRB 131128A: MASTER-Net optical observations
- GRB 131128A: Nanshan afterglow candidate
- GRB 131127B: MASTER-Net optical observations
- GRB 131128A: Swift detection of a burst
- GRB 131127A: Bassano Bresciano Observatory optical upper limit
- GRB 131127B: Nanshan optical observations
- Konus-Wind observation of GRB 131127B
- IPN Triangulation of GRB 131127B
- GRB 131127B: Fermi GBM detection
- GRB 131127A: Swift/UVOT Upper Limits
- GRB 131127A: AROMA-N Optical Observation
- GRB 131127A: RATIR Optical and NIR Observations, High-z Candidate
- Fermi407254341: iPTF optical afterglow candidates
- GRB 131127A: Swift-XRT refined Analysis
- GRB 131127A. 1.5m OSN optical limit
- GRB 131127A, Swift-BAT refined analysis
- GRB 131127A: Enhanced Swift-XRT position
- GRB 131127A: Mondy optical upper limit
- GRB 131127A: Nanshan optical upper limit
- GRB 131127A: MASTER-NET optical observations
- GRB 131127A: Swift detection of a burst
- GRB 131122A: Swift/UVOT Upper Limits
- GRB 131122A: Upper limit from NOT imaging
- GRB 131122A: Swift-XRT observations
- GRB 131122A: i-band observations from NOT
- GRB 131122A: Nanshan optical upper limit
- GRB 131122A: a long GRB detected with INTEGRAL
- GRB 131122A (INTEGRAL trigger N6392): MASTER-NET optical observation
- GRB 131120A, Swift-BAT refined analysis
- Konus-Wind observation of GRB 131118A
- IPN Triangulation of GRB 131118A
- GRB 131120A: Swift detection of a burst
- Fermi Gamma-ray Burst Monitor trigger 406601061 / 131120031 is not a GRB
- GRB 131118A: Fermi GBM detection
- GRB 131108A: VLA Observations
- GRB 131030A, Optical Observations
- GRB 131117A, Swift-BAT refined analysis
- Fermi GBM trigger 406351590 / 131117143 is not a GRB
- GRB 131117A: TAROT La Silla observatory optical observations
- GRB 131117A: Swift/UVOT Detection
- GRB 131117A: Swift-XRT refined Analysis
- GRB 131117A: VLT/X-shooter redshift
- GRB 131117A: GROND confirmation of the afterglow and photo-z.
- GRB 131117A: Enhanced Swift-XRT position
- GRB 131117A: Skynet PROMPT optical detection of an afterglow
- GRB 131117A: Swift detection of a burst
- GRB 130925A: HST imaging
- GRB 131110A: Swift-XRT and UVOT upper limits
- GRB 131110A BAT refined analysis