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"- Fermi GBM trigger 334123030 (110804165) is not a GRB
- IPN triangulation of GRB110802A (short/hard burst)
- GRB 110801A: optical observations in CrAO
- EVLA observation for Fermi burst GRB 110721A
- GRB 110731A : Suzaku WAM observation of the prompt emission
- GRB 110726A: Swift-XRT refined Analysis
- GRB110731A: MOA optical observations of the steeply fading afterglow
- GRB 110801A: SAO RAS optical observations
- GRB110801A: MITSuME Ishigakijima Optical Observation at 1 day after the burst
- GRB 110801A: Evidence for a jet break
- GRB 110801A: MASTER OT observations
- GRB 110801A: Swift-BAT refined analysis
- Swift/UVOT observations of GRB110801A
- GRB 110801A: Swift-XRT refined Analysis
- GRB 110801A: Afterglow redshift from 10.4m GTC
- GRB110801A: MITSuME Ishigakijima Optical Observation
- GRB 110801A: Enhanced Swift-XRT position
- AXP 4U 0142+61: Fermi GBM detection
- GRB 110801A: TLS Optical afterglow confirmation
- GRB 110801A: ROTSE-III Detection of re-brightening from OT
- GRB 110801A: Swift detection of a burst with an optical counterpart
- GRB 110731A / EVLA upper limits
- GRB110731A: MITSuME Ishigakijima Optical Upper Limits
- GRB 110731A Gemini-N redshift
- GRB 110731A: Swift-XRT refined Analysis
- Konus-Wind observation of GRB 110731A
- GRB110731A: Swift/UVOT Observations
- GRB 110731A: Fermi GBM observation
- GRB 110731A: NOT photometry
- GRB 110731A: Enhanced Swift-XRT position
- Fermi-LAT Detection of GRB110731A
- GRB 110731A: Swift-BAT refined analysis
- GRB 110731A: FTN+FTS afterglow observations
- GRB 110731A: Swift detection of a burst with an optical counterpart
- Sw J1644+57 (GRB 110328A): Continued VLBA Observations
- INTEGRAL Weak trigger #6331: GRT Optical Observation
- GRB 110721A: Swift observations of afterglow candidate
- AXP 4U 0142+61: Swift-BAT refined analysis
- GRB 110726A: optical upper limit in CrAO
- Swift detection of a SGR-like burst from the AXP 4U 0142+61
- Swift triggers 458268 and 458269 are not astrophysical
- GRB 110726A: EVLA observations
- GRB 110726A: IAC80 R-band observations
- GRB 110726A: ROTSE-III refined analysis, fast decay in early phase
- GRB110726A: MITSuME Ishigakijima Optical Observation
- GRB 110726A: Further Swift/UVOT Observations
- GRB110726A: Gemini-N tentative redshift
- GRB 110726A: Swift-BAT refined analysis
- GRB 110726A: Enhanced Swift-XRT position
- GRB 110726A: Swift/UVOT Detection
- GRB 110726A: Liverpool Telescope observations
- GRB 110726: ROTSE-III Detection of Optical Counterpart
- 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