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"
- GRB051016: Swift XRT refined analysis.
- GRB051016: Planned XMM-Newton observation
- GRB 051016: LCO optical and near-IR imaging
- GRB 051016: PROMPT Observations
- GRB051016: Swift detection of a burst
- Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
- GRB051006: optical observations
- GRB 051012: Swift-BAT detection of burst yesterday
- Swift trigger 159578 is not a burst
- Swift-BAT Trigger 159578 is a possible burst
- GRB050805A: Rc optical observations
- GRB 051006: Swift/UVOT Upper Limits
- IBAS Alert 2675 : not a GRB
- GRB051008: optical candidate
- GRB 051008: - a high redshift high-luminosity burst?
- GRB 051008 - a low redshift low-luminosity burst?
- IBAS Alert 2673: not a real GRB
- GRB051011: bright nebulae near error box
- GRB051011: MASTER optical observation
- GRB051008: optical observation
- GRB051008: Swift XRT refined analysis
- GRB051008 - Swift UVOT upper limits
- Konus-Wind observation of GRB 051008
- GRB051008: Final refined analysis of the Swift-BAT burst
- GRB 051008: R-band upper limit
- GRB051008: Refined analysis of the Swift-BAT burst
- GRB051008: Radio Observation
- GRB 051008: Swift XRT position
- GRB 051008, optical observations
- GRB 051008: early Swift XRT analysis
- GRB 051008: Swift UVOT Candidate
- GRB051008: Swift-BAT detection of a bright burst
- GRB 051006: P60 Observations
- grb test
- GRB 051006: XRT refined analysis
- Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
- GRB 051006: optical observations at Sierra Nevada
- GRB051006: Refined analysis of the Swift-BAT burst
- GRB 051006: XRT position
- GRB051006: Swift detection of a burst
- GRB 050906, summary of radio observations
- Swift-BAT triggers 158261 and 158262 Retraction
- GRB051001: Swift UVOT Upper Limits
- GRB 050925: Second Epoch WSRT Radio Observations
- GRB 051001: Swift XRT refined analysis
- GRB 051001, optical observations at Mt. John
- GRB 051001: I-band limit
- GRB 051001: AAT infra-red observations
- GRB 051001: Swift-BAT refined analysis
- GRB 051001: Swift Detection of a Burst
- GRB 051001: ROTSE-III Optical Limits
- GRB050908: optical observations
- GRB050922C: optical observation
- GRB050922B: optical limit
- GRB 050922C: further VLT observations
- GRB 050820A: NIR photometry at the TNG
- GRB050922C: UVES/VLT high resolution spectroscopy
- GRB050925: Swift/XRT limits
- GRB/SGR 050925: IR Observations
- GRB050922C - Swift UVOT preliminary analysis
- GRB 050922C: break in the lightcurve
- GRB 050925: WSRT Radio Observations
- GRB050925: Swift UVOT upper limits
- Refined analysis of the Swift-BAT soft short burst
- GRB 050925 : I-band observation at Xinglong observatory
- GRB050925: Faulkes Telescope North R-band limit
- GRB050925: Swift-BAT detection of a short burst
- GRB 050922B: Correction to BAT refined analysis, longer burst
- GRB050922C: TNG spectroscopic observations
- GRB050922B: refined XRT analysis
- Konus-Wind observation of GRB 050922C
- GRB 050922C: Refined redshift
- GRB050922B: Swift UVOT early upper limits.
- GRB OT observation
- GRB050922C: observation at MonteBoo
- INT 2.5m limit for GRB050922B
- GRB 050922B: optical limit
- GRB050922C: Optical Observations
- GRB 050922C: Swift XRT refined analysis
- HETE Fregate observations of GRB 050922C
- GRB 050922C: Swift-BAT refined analysis
- GRB 050922B: Swift-BAT refined analysis
- GRB050922C: optical observations
- GRB 050922C: Absorption redshift from the Nordic Optical Telescope
- GRB 050922C: optical obserations
- GRB 050922C: NOT optical observations
- GRB 050922A: Analysis of Swift/XRT TOO observation
- GRB 050922C: Swift detection of a bright burst
- GRB 050922C: ROTSE-IIId Refined Analysis
- GRB 050922C: ROTSE-III Detection of Possible Counterpart
- GRB 050922B: ROTSE-III Optical Limits
- GRB 050922B,optical observation
- GRB050922B: Swift-BAT detection of a weak long burst
- Possible GRB 050922 detected by INTEGRAL
- GRB050918: Possible Swift/XRT detected afterglow
- GRB050820B: analysis of the XMM-Newton observation
- GRB050916: Swift/UVOT Upper Limits
- GRB 050916: Swift-BAT refined analysis
- GRB 050918 - A long GRB detected by INTEGRAL
- GRB 050915a: Radio Observations