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"20391 results found.
- RXTE Discovery of the Spin Period of Swift J1834.9-0846
- GRB 110808A: Swift/UVOT Detection
- GRB 110808A: Enhanced Swift-XRT position
- GRB 110808A: Swift detection of a burst with optical counterpart
- GRB 110807A: SAO RAS observations
- GRB 110807A: Swift detection of a burst or a posible new SGR
- GRB 110726A: two epochs of SAO RAS optical observations
- IPN triangulation of GRB110802A (short/hard burst)
- GRB 110801A: optical observations in CrAO
- EVLA observation for Fermi burst GRB 110721A
- GRB 110726A: Swift-XRT refined Analysis
- GRB 110801A: SAO RAS optical observations
- GRB110801A: MITSuME Ishigakijima Optical Observation at 1 day after the burst
- Swift/UVOT observations of GRB110801A
- GRB110801A: MITSuME Ishigakijima Optical Observation
- GRB 110801A: Enhanced Swift-XRT position
- GRB 110801A: Swift detection of a burst with an optical counterpart
- GRB110731A: MITSuME Ishigakijima Optical Upper Limits
- GRB110731A: Swift/UVOT Observations
- GRB 110731A: NOT photometry
- GRB 110731A: Enhanced Swift-XRT position
- GRB 110731A: Swift detection of a burst with an optical counterpart
- INTEGRAL Weak trigger #6331: GRT Optical Observation
- GRB 110721A: Swift observations of afterglow candidate
- GRB 110726A: optical upper limit in CrAO
- Swift detection of a SGR-like burst from the AXP 4U 0142+61
- GRB110726A: MITSuME Ishigakijima Optical Observation
- GRB 110726A: Further Swift/UVOT Observations
- GRB110726A: Gemini-N tentative redshift
- GRB 110726A: Enhanced Swift-XRT position
- GRB 110726A: Swift/UVOT Detection
- GRB 110726A: Swift detection of a burst
- IPN triangulation of GRB 110721A
- GRB 110721A: Preliminary Swift/UVOT Upper Limits
- GRB 110721A: potential counterpart candidate
- GRB 110721A: Fermi-LAT detection
- Recent GCN/Swift-BAT Slew Burst Position notices are due to playback debugging
- 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: optical upper limit
- GRB 110719A: Enhanced Swift-XRT position
- GRB 110719A: Swift detection of a burst
- 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
- GRB 110715A: Swift/UVOT Detection
- GRB 110715A: Enhanced Swift-XRT position
- 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
- Swift trigger 457076 is not a GRB
- 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
- GRB 110709A: Konkoly observations
- GRB 110708A: Konkoly observations
- GRB 110709B BAT refined analysis
- GRB 110709B: Swift/UVOT Detection of Possible Optical Flaring
- GRB110709A: MITSuME Ishigakijima Optical upper limits
- GRB 110709B: Enhanced Swift-XRT position
- GRB 110709B: GROND Detection of an Afterglow Candidate
- GRB 110709B: Gemini-South optical observations
- GRB 110709A: Enhanced Swift-XRT position
- GRB 110709B: Swift detection of a burst
- GRB 110708A: Swift/UVOT Observations
- GRB 110709A: Swift detection of a burst
- GRB 110708A: Swift/XRT afterglow candidate for the INTEGRAL burst
- 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 detection of a soft gamma repeater burst
- 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
- GRB 110625A: GROND detection of a source inside the XRT error circle
- GRB 110625A: Konkoly observations
- GRB 110625A: Swift-XRT refined Analysis
- Swift J185003.2-005627: NIR Observation
- GRB 110625A: Swift detection of a burst
- Swift J185003.2-005627: Swift-XRT/UVOT refined analysis
- Swift J185003.2-005627: Swift-BAT refined analysis
- Swift J185003.2-005627: TAROT La Silla observatory optical observations
- Swift J185003.2-005627: TAROT Calern observatory optical observations
- Swift J185003.2-005627: Swift detection of a burst from a new Galactic transient
- SGR 1E 1841-045: Swift detection of a soft gamma repeater burst
- Konus-Wind observation of GRB 110618A
- IPN triangulation of GRB110618A (long duration, extremely intense)
- GRB 110610A: 1.23m CAHA optical observations
- GRB 110610A: Swift/UVOT Upper Limits
- GRB 110610A: Enhanced Swift-XRT position
- Swift detection of the X-ray afterglow of GRB 110604A