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"
18435 results found.
- RXTE Discovery of Pulsations from SGR 0418+5729
- GRB 090531B: Fermi GBM detection
- Discovery of a new soft gamma repeater source, SGR 0418+5729
- GRB 090607: XRT Team Refined Analysis
- GRB 090607: Swift/UVOT Upper Limits
- GRB 090607: Swift-BAT refined analysis of the SHB
- GRB 090607: Faulkes Telescope North observations
- GRB 090607: Swift detection of a burst
- Ignore GCN/Swift-BAT Lightcurve Notices for trigger 353567
- GRB 090530: RTT150 Optical Observation
- GRB 090529A: RTT150 Optical Observations
- GRB 090531B: GROND observation
- GRB 090530: Early RAPTOR Optical Observations
- GRB 090531B: Swift/BAT spectral lag results
- Corrections to GRB 090531B Swift/UVOT Upper Limits
- GRB 090531B, RIMOTS optical upper limits
- GRB 090531B: Swift/UVOT Upper Limits
- GRB 090530: GRT Optical Observation
- GRB 090531B: Swift-BAT refined analysis
- Initial Swift/UVOT observations of GRB 090531B
- GRB 090531B: Swift-XRT candidate afterglow position
- GRB 090531B: ROTSE-III Optical Limits
- GRB 090531B: Swift detection of a burst
- GRB 090531: Swift-BAT refined analysis
- GRB 090530: break in light curve
- GRB 090531: GROND upper limits
- GRB 090531: Swift detection of a burst
- GRB090530: Swift XRT refined analysis
- GRB090530: Swift/UVOT afterglow detection
- GRB 090529: Swift-XRT refined analysis
- GRB 090530: Enhanced Swift-XRT position
- GRB 090530: Swift-BAT refined analysis
- GRB 090530: PAIRITEL NIR Detections
- GRB 090530A: ROTSE-III Detection of Optical Counterpart
- GRB 090530: Swift detection of a burst with an optical counterpart
- GRB 090529: optical observations
- GRB 090529: TLS Afterglow Observations
- GRB090529: UVOT/Swift detection of a brightening optical afterglow
- GRB 090529: Swift-BAT refined analysis
- GRB 090529: Enhanced Swift-XRT position
- GRB 090529: Preliminary Swift/UVOT Upper Limit
- GRB 090529: Swift detection of a burst
- GRB 090520B: Fermi GBM detection
- GRB 090516A: Konus-Wind and Swift/BAT joint spectral analysis
- GRB 090518: Fermi GBM detection
- GRB 090520 Swift-BAT detection of a burst in ground analysis
- GRB 090423: Fermi GBM T90 follow-up analysis results
- GRB 090516: Fermi GBM observation
- GRB 090519: Swift-XRT refined analysis
- GRB 090519: GROND observation
- GRB 090519: Swift/UVOT Upper Limits
- GRB 090519, Swift-BAT refined analysis
- GRB 090519: Enhanced Swift-XRT position
- GRB 090519: FARO Chante Perdrix Observatory optical observations
- GRB 090519: TAROT Calern observatory optical observations
- GRB 090519: Swift detection of a burst
- GRB 090518: Swift/UVOT Upper Limits
- GRB 090518, Swift-BAT refined analysis
- GRB 090516, RIMOTS optical upper limits
- GRB090518 : Optical upper limit by MOA-II telescope
- GRB 090518: Swift-XRT refined analysis
- GRB 090518: Enhanced Swift-XRT position
- GRB 090518: Swift detection of a burst
- GRB 090515: Swift/BAT spectral lag results
- GRB 090516: Swift-BAT refined analysis
- GRB 090516: GROND OBSERVATIONS
- GRB 090516 - Zadko Telescope observations
- GRB 090516: Swift XRT refined analysis
- GRB 090516: Swift/UVOT Observations
- GRB 090516: Enhanced Swift-XRT position
- GRB 090516: Faulkes Telescope South optical afterglow
- GRB 090516: Swift detection of a burst
- GRB 090515: ROVOR Upper Limit
- GRB 090515: MMT/MMIRS NIR Upper Limit
- GRB 090515: Swift/UVOT Observations
- GRB 090515: Swift-XRT refined analysis
- GRB 090515: Enhanced Swift-XRT position
- GRB 090509: Fermi GBM observation
- GRB 090515: Swift-BAT refined spectral analysis
- GRB 090515: Swift-BAT refined analysis
- GRB 090509 - Zadko Telescope observations
- GRB 090515: Super-LOTIS Upper Limits
- GRB 090515: PAIRITEL Upper Limits
- GRB 090515: KAIT optical upper limits
- GRB 090515: ROTSE-III Optical Limits
- GRB 090515: Swift detection of a short burst
- GRB 090510: Suzaku WAM observation of the prompt emission
- GRB090510: VLT/FORS2 spectroscopic redshift
- GRB 090510: GROND observations
- GRB 090510: Swift/UVOT host galaxy candidates
- GRB 090510: Fermi-LAT follow-up analysis
- GRB 090509, further Swift-BAT refined analysis
- Konus-Wind observation of GRB 090510
- GRB 090510: UVOT refined analysis
- GRB 090510: Swift XRT refined analysis
- GRB 090510: Enhanced Swift-XRT position
- GRB 090510: NOT afterglow confirmation
- GRB 090510: Swift-BAT refined analysis
- GRB 090510: Fermi GBM detection
- GRB 090509: Swift-BAT refined analysis