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 130716A: UVOT Upper Limits
- GRB 130716A: Probable short-hard burst with delayed Swift data
- GRB 130715A: Fermi GBM detection
- GRB 130626A: Retraction of possible X-ray afterglow
- GRB 130702A: Maidanak optical observations
- GMRT radio detection of GRB 130702A
- GRB 130708A: Swift XRT and UVOT Observations
- GRB 130702A: TNG spectroscopic observations of the emerging supernova
- GRB 130708A: Fermi GBM observation
- GRB 130702A: P200 Spectroscopic Confirmation of Associated Supernova
- GRB 130708A found in ground analysis of Swift-BAT data
- GRB 130702A: Maidanak optical observations
- GRB 130628A: Suzaku WAM observation of the prompt emission
- GRB130702A: NOT observation - the detection of an emerging supernova
- GRB 130702A: Continued RATIR Optical and NIR Observations
- GRB 130702A: Xinglong TNT optical observation
- GRB 130702A: Continued UVOT Observations
- GRB 130702A: VLA detection
- GRB 130702A (= Fermi 394416326): correction of the GCN #14988 title
- GRB 130702Ð
- GRB 130702A: WSRT radio detection
- Konus-Wind observation of GRB 130702A
- GRB130702A: Redshift of Afterglow Candidate iPTF13bxl
- GRB 130702A: further TNG observations
- GRB 130702A: NOT spectroscopy and redshift of the nearby bright galaxy
- GRB 130702A: further Swift-XRT observations
- GRB 130702A: Continued P60 observations
- GRB 130702A: RATIR Optical and NIR Observations
- GRB 130702A: CARMA 3mm detection
- GRB 130702A: NOT optical observations
- GRB 130702A: TNG optical observations
- GRB 130702A / Fermi394416326 : Nanshan optical observations
- IPN localization of GRB 130702A (= Fermi 394416326)
- Fermi GRB 130702A: Swift XRT and UVOT observations
- GRB 130702A / Fermi394416326: Fermi GBM detection
- GRB 130702A / Fermi394416326 : Fermi-LAT detection of a burst
- Fermi GBM trigger 394416326: MASTER early optical limit
- GRB 130628A: Fermi GBM detection
- Fermi394416326: FTN detection
- Fermi394416326: iPTF detection of a possible optical afterglow
- GRB 130627B: Swift afterglow confirmation
- Fermi GBM trigger 394325281 / 130630950 is not a GRB
- GRB 130623A: Second Swift-XRT observation
- GRB 130701A: MITSuME Akeno Optical observation
- GRB 130701B: Fermi GBM detection
- GRB 130701A: Swift-XRT refined Analysis
- GRB 130701A: P60 Observations
- GRB 130701A, Swift-BAT refined analysis
- Konus-Wind observation of GRB 130701A
- GRB 130701A: Swift/UVOT Detection
- GRB 130701A: VLT/X-shooter redshift
- GRB 130701A: Enhanced Swift-XRT position
- GRB 130701A: optical afterglow from the NOT
- GRB 130701A: Swift detection of a burst
- GRB 130627B, Swift-BAT refined analysis
- GRB 130627A, Swift-BAT refined analysis
- GRB 130627B: Swift/UVOT Upper Limits
- GRB 130627A: Swift/UVOT Upper Limits
- GRB 130627A: Swift-XRT refined Analysis
- GRB 130627B: Possible Swift-XRT afterglow detection
- Swift trigger 559221 is likely a false trigger coincident with IGR J17544-2619
- GRB 130627A: Enhanced Swift-XRT position
- GRB 130626A: KAIT Optical Observations
- GRB 130626A: RATIR Optical Observations
- GRB 130626A, Swift-BAT refined analysis
- GRB 130627A: Fermi GBM detection
- GRB 130623A: Fermi GBM detection
- GRB130627B: Swift/UVOT Observations
- GRB 130627B: Swift-XRT observations
- GRB 130626A: Swift-XRT possible detection and UVOT upper limits
- GRB 130627B: Swift detection of a burst
- GRB 130627A: Swift-XRT observations
- GRB 130627A: Swift/UVOT Observation
- GRB 130627A: Swift detection of a burst
- Swift Trigger 559108 is not astrophysical
- GRB 130626A: Swift detection of a short burst
- GRB 130625A: Swift-XRT refined Analysis
- GRB 130625A: MASTER afterglow limit
- GRB 130625A: Swift/UVOT Upper Limits
- GRB 130625A: Nanshan optical upper limit
- GRB 130623A: Swift-XRT and UVOT observations
- GRB 130625A: Swift-BAT refined analysis
- GRB 130625A: Enhanced Swift-XRT position
- GRB 130625A: Swift detection of a burst
- GRB 130603B: First epoch of XMM-Newton observations
- GRB 130623A detected in ground analysis of Swift-BAT data
- Swift Trigger 558828 is not an interesting event
- Swift Trigger 558631: AAO optical observations
- GRB 130614A: Suzaku WAM observation of the prompt emission
- Swift Trigger 558631 is not a real source
- GRB 130612A: Swift-BAT refined analysis
- GRB 130609B: Suzaku WAM observation of the prompt emission
- GRB 130612A: Continued Skynet/PROMPT/GORT/DSO observations
- GRB 130603B: Analogy with GRB 090510A and possible connection with a supernova
- Fermi/GBM observation of the Soft Gamma Repeater SGR J1550-5418
- Trigger 558399: Swift detection of the Soft Gamma Repeater AXP 1E1547.0-5408
- Swift Trigger 557910 is not astrophysical
- GRB 130615A: Continued Skynet/PROMPT Observations
- GRB 130610A: TAROT La Silla observatory optical observations
- GRB 130610A: CrAO optical observations