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.
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 060912B: Watcher observations
- GRB060912: Swift/UVOT Observations
- GRB060912: OPTIMA-Burst optical observations
- GRB 060912B: a long GRB detected with INTEGRAL
- GRB 060912: Swift XRT Team Refined Analysis
- GRB 060912, Swift-BAT refined analysis
- GRB 060912: Correction to GCN 5559
- GRB 060912: Xinglong TNT optical observations
- GRB 060912: Swift detection of a burst with an optical afterglow
- GRB060906: Danish/DFOSC optical observations
- VLA observations of GRB 060908
- GRB 060908: redshift
- GRB 060908, Swift/XRT refined analysis
- GRB 060908: Swift/UVOT Observations
- GRB 060908: Danish/DFOSC optical observations
- GRB 060908, Swift-BAT refined analysis
- GRB 060908 - SDSS Pre-burst Observations
- GRB 060904B : CFHT/WIRCam NIR afterglow observations
- GRB 060904B: Kiso Optical observation
- GRB 060904A : Optical limit
- GRB 060908: REM optical prompt observation
- GRB 060908: PROMPT Detection of a Bright Counterpart
- GRB 060908: Swift detection of a burst with a bright optical counterpart
- GRB 060904A: Suzaku/WAM observation of the prompt emission
- GRB060906 , optical observation
- GRB060904b optical detections (delayed report due to internet outage)
- GRB 060906: optical observation
- GRB 060906: Early RAPTOR optical limits
- GRB 060906, Swift-BAT refined spectral analysis
- GRB 060906: Swift/XRT Refined Analysis
- GRB 060906: Swift-UVOT observations
- VLT redshift of GRB 060906
- GRB 060906, Swift-BAT refined analysis
- GRB 060906: FRAM observations - flash determination (airplane)
- GRB 060906: KAIT observations
- GRB 060906: Confirmation of P60 Optical Afterglow
- GRB 060906: observations with FRAM
- GRB 060906 (?): P60 Optical Afterglow Candidate
- GRB 060906: Swift detection of a probable burst
- GRB 060904A Milagro GeV/TeV Observations
- GRB060904b, optical observations
- GRB 060904b: SMARTS optical/IR afterglow observations
- GRB 060904B: RTT150 optical observations
- GRB060904A: Swift/UVOT optical observations
- GRB 060904A: Subaru NIR observation
- GRB 060904A: pseudo-z from spectral parameters of the prompt emission
- GRB 060904B: Swift-BAT refined analysis
- GRB060904b: Optical observations with Swift/UVOT
- Konus-Wind observation of GRB 060904A
- GRB 060904B: Swift-XRT refined analysis
- GRB 060904A: Refined analysis of the Swift-BAT burst
- GRB 060904A: Swift-XRT refined analysis
- GRB 060904A: Suzaku-XIS and -HXD observation plan
- GRB 060904B: VLT redshift
- GRB 060904A: P60 Observations
- GRB 060904B: Optical observations at Crni Vrh
- GRB060904B: Watcher observations
- GRB 060904B BOOTES-IR and 1.5m OSN observations
- GRB 060904B: TAROT optical counterpart observations
- GRB060904B - SDSS Pre-Burst Observations
- GRB 060904: TAROT optical observations
- GRB 060904B: Swift detection of a burst with optical counterpart
- GRB 060904B: ROTSE-III Detection of Optical Counterpart
- GRB060904 - SDSS Pre-Burst Observations
- GRB 060904: Swift detection of a bright burst
- GRB060901: Optical observations
- 060901: Swift UVOT followup observations
- GRB 060901: pseudo-z from spectral parameters of the prompt
- Konus-Wind observation of GRB 060901
- GRB 060901: SMARTS optical/IR observations update
- GRB 060901: Swift/XRT Refined Analysis
- GRB 060901: SMARTS optical/IR observations
- GRB 060901: Swift/XRT Position
- GRB 060901: further INTEGRAL results
- GRB 060901: Watcher observations
- GRB 060901: a long GRB detected by INTEGRAL
- Two bright bursts from SGR 1806-20 detected with IBAS
- GRB 060605, observations using an Integral Field Unit
- GRB 060604: VLA Observation
- GRB 060814: Suzaku/WAM observation of the prompt emission
- GRB 060605: VLA Observation
- GRB 060707: VLA observation
- GRB 060825: VLA observations
- GRB 060825: pseudo-z from spectral parameters of the prompt emission
- Swift-BAT trigger 226614 is not a GRB
- GRB060826 - SDSS Pre-Burst Observations
- GRB 060826(?): Swift detection of a possible burst
- GRB 060825: XRT Team Refined Analysis
- GRB 060825: Swift-BAT Refined Analysis
- GRB 060813: Swift/BAT, Konus-Wind, and Suzaku/WAM joint prompt spectral analysis
- GRB060825: Liverpool Telescope optical observations
- GRB 060825: TNG optical observations
- GRB 060825: TAROT optical observations
- GRB 060825: P60 Observations
- GRB060825: BOOTES-IR optical observations
- GRB 060825: Swift detection of a burst
- GRB060801: host galaxy redshift
- GRB060729: analysis of XMM-Newton observation
- GRB 060814: pseudo-z from spectral parameters of the prompt
- IBAS Alerts No 3429 and 3430: not GRBs