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 110726A: Swift detection of a burst
- IPN triangulation of GRB 110721A
- GRB 110721A: Preliminary Swift/UVOT Upper Limits
- GRB 110721A: Gemini-South spectroscopy of the potential optical counterpart
- GRB 110721A: potential counterpart candidate
- Konus-Wind observation of GRB 110721A
- GRB 110709B / EVLA detection of radio counterpart
- GRB 110719A / SMA 345 GHz upper limits
- GRB 110721A: Fermi-LAT detection
- GRB 110721A: Fermi GBM detection
- Recent GCN/Swift-BAT Slew Burst Position notices are due to playback debugging
- GRB110715A: spectral lag analysis
- GRB 110715A : Suzaku WAM observation of the prompt emission
- GRB 110719A: GRT Optical Observation
- GRB 110719A: optical limit by "Pi of the Sky"
- GRB 110719A: z-band upper limit
- Swift/UVOT observations of GRB110719A
- Swift J1822.3-1606 : Fermi GBM observation
- GRB 110719A: Swift-XRT refined Analysis
- GRB 110719A: optical upper limit
- GRB 110719A: Enhanced Swift-XRT position
- GRB 110719A: Swift-BAT refined analysis
- GRB 110715A optical observations
- GRB 110719A: Swift detection of a burst
- GRB 110709B : Suzaku WAM observation of the prompt emission
- GRB 110715A: ATCA detection of the radio counterpart
- Swift J1822.3-1606: Transient Magnetar or Be X-ray Binary?
- GRB110715A: GROND Detection of the Optical/NIR Afterglow
- GRB 110715A: APEX detection of the submm counterpart
- Swift J1822.3-1606
- Konus-Wind observation of GRB 110715A
- GRB 110715A: Swift-XRT refined Analysis
- GRB110715A: VLT redshift
- Swift J1822.3-1606: Swift-XRT detection of the X-ray counterpart
- GRB 110715A: Swift/UVOT Detection
- GRB 110715A: Enhanced Swift-XRT position
- GRB 110715A: Swift-BAT refined analysis
- Swift J1822.3-1606: A Probable New SGR in Ground Analysis of BAT Data
- GRB 110715A: Swift detection of a bright burst with an optical counterpart
- GRB 110709B: Swift/UVOT Observations
- GRB 110709A / EVLA upper limits
- GRB 110709B: Additional Gemini observations and deep limits on an optical afterglow
- Swift trigger 457076 is not a GRB
- Konus-Wind observation of GRB 110708B
- GRB 110709A: Suzaku WAM observation of the prompt emission
- GRB 110709B: Submm observations from APEX
- IPN triangulation of GRB 110708B (long duration, extremely intense)
- Swift Trigger 457076: a possible GRB
- GRB 110709A: Swift/UVOT Upper Limits
- Fermi Gamma-ray Burst Monitor trigger 332078586 is not a GRB
- GRB 110709A: Konkoly observations
- GRB 110708A: Konkoly observations
- GRB 110709B BAT refined analysis
- GRB 110709B: burst detection from Swift-BAT slew data
- GRB 110709B: Swift-XRT refined Analysis
- GRB 110709A: Swift-XRT refined Analysis
- GRB 110709B: Swift/UVOT Detection of Possible Optical Flaring
- GRB110709A: MITSuME Ishigakijima Optical upper limits
- Konus-Wind observation of GRB 110709A
- GRB 110709B: correction to GCN 12135 (Konus-Wind peak flux)
- GRB 110709B: Enhanced Swift-XRT position
- Konus-Wind observation of GRB 110709B
- GRB110709A: upper limits from CAHA 1.23m and OSN 1.5m
- GRB 110709A: Fermi GBM observation
- GRB 110709B: Gemini-South additional analysis and photometry
- GRB 110709B : A possible source in USNO B 1.0
- GRB 110709B: Preliminary Swift-BAT refined analysis
- GRB 110709B: GROND Detection of an Afterglow Candidate
- GRB 110709B: Gemini-South optical observations
- GRB 110709A: Swift-BAT refined analysis
- GRB 110709B: possible quiescent source in DSS
- GRB 110709A : Xinglong TNT upper limit
- GRB 110709B: Swift detection of renewed activity at T+11 minutes.
- GRB 110709A: Enhanced Swift-XRT position
- GRB 110709B: Swift detection of a burst
- GRB 110708A: Swift/UVOT Observations
- GRB 110709A: MASTER-NET optical observations
- GRB 110709A: Prompt enhanced Swift-XRT position
- GRB 110709A: Swift detection of a burst
- GRB 110708A: Liverpool Telescope observations
- GRB 110708A: Lick observations
- GRB 110708A: Swift/XRT afterglow candidate for the INTEGRAL burst
- GRB 110705A: Suzaku WAM observation of the prompt emission
- GRB 110625A, the review of the sky area in plate archives
- GRB 110708A: a long GRB detected by INTEGRAL
- Konus-Wind observation of GRB 110705A
- IPN triangulation of short hard GRB 110705A
- Swift trigger 456780 is not a burst
- GRB 110705A: Fermi GBM detection
- Swift Trigger 456659 is probably not astrophysical
- Swift-BAT trigger 456532 is not astrophysical
- SGR 1E 1841-045: early optical limit by "Pi of the Sky"
- SGR 1E 1841-045: Swift-BAT refined analysis
- SGR 1E 1841-045: Swift detection of a soft gamma repeater burst
- GRB 110625A: Suzaku WAM observation of the prompt emission
- Swift J185003.2-005627: 1.23m CAHA and BOOTES-3 observations
- GRB 110625A: Fermi GBM and LAT observations
- GRB 110625A: Swift/UVOT Upper Limits
- GRB 110625A: 1.23m CAHA I-band observations
- GRB 110625A: Fermi LAT detection