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"
17213 results found.
- GRB991216, UBVRIJHK field photometry
- GCN resumes full operations
- GRB 991216: Detection of the Host and/or Absorber Galaxy
- GRB 991216 RXTE ASM Observations
- GRB 991217 (SAX J2303.2+0015) Optical observations
- Chandra observation of the X-ray afterglow of GRB991216
- SAX J2303.2+0015 Optical observations
- IR observations of GRB991216
- GRB 991217 (SAX J2303.2+0015) Optical observations
- GRB 991216 Radio Observations
- GRB 991208 Infrared Detection
- GRB991216
- GRB 991216--Summary of RXTE Observations
- GRB 991216 Optical Observations
- GRB 991216, optical observations
- GRB 991208 SAO-RAS Spectroscopy
- SAX J2303.2+0015: an x-ray/GRB?
- GRB 991216, Optical Transient
- GRB991216 ('Beethoven Burst') B, R, and K Observations
- GRB991216, infrared observations
- GRB 991208 optical observations
- GRB 991216 Optical Observation
- GRB 991216: Extremely bright BATSE burst
- R-band Observations of GRB991208 at TNG
- GRB991208, optical observations
- GRB 991208, Optical Observation
- GRB991208, optical observations
- IPN localization of GRB991208
- Optical Observations of GRB991105
- GRB991106: BeppoSAX/BATSE results
- BeppoSAX NFI Observation of GRB991106
- GRB 991106, radio observations
- GRB991106: the first BeppoSAX short GRB detection?
- GRB 991106 Optical Observations
- GRB991106, optical observation at SAO-RAS
- GRB 991106, LOTIS Optical Observations
- GRB991105: SAX-GRBM/-WFC detection
- GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
- GRB 991014, Optical Observations
- GRB 991014 - BeppoSAX NFI observations
- GRB 991014, radio observations
- GRB 991014, Optical Observations
- GRB 991014, optical observations
- Optical Observations of GRB990907
- GRB990907: BeppoSAX follow up and X-ray afterglow
- GRB990907 and 990908
- GRB990908, another BeppoSAX-GRBM/WFC burst detection
- BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
- GRB990806 BeppoSAX follow up
- GRB 990806 Optical observations
- GRB 990806, optical observations
- GRB 990806, Optical Observations
- GRB990806: possible X-ray afterglow, BeppoSAX
- GRB 990712 Optical Observations
- GRB 990712
- Late-time HST/STIS Observations of GRB 990510
- BeppoSAX NFI Observation of GRB990705
- BeppoSAX NFI Observation of GRB990705
- GRB 990705, R-band observations
- GRB990704: SAX-NFI results summary
- GRB990704 radio and optical observations
- GRB990704
- GRB990704, optical observations
- GRB990704: possible X-ray afterglow
- GRB990704
- GRB990704: BeppoSAX detection
- BeppoSAX NFI Observation of GRB990627 X-ray afterglow
- GRB 990627, radio observations
- Late-time HST/STIS Observation of GRB 990123
- Optical Observations of GRB 990506
- GRB 990506 Radio Transient
- GRB990527 Optical Observations
- X-ray/GRB 1SAX J0835.9+5118, Optical Observation
- IPN error box for GRB990527
- X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
- X-ray/GRB 1SAX J0835.9+5118, Optical Observations
- X-ray/GRB 1SAX J0835.9+5118, Optical Observation
- X-ray/GRB 1SAX J0835.9+5118, Optical Observation
- X-ray/GRB 1SAX J0835.9+5118, Optical Observation
- radio observations of X-ray/GRB transient field
- optical observation of the X-ray/GRB transient SAX J0835.9+5118
- Optical report on X-ray/GRB transient
- radio detection of X-ray/GRB transient
- GRB 990510: optical linear polarization
- GRB 990510: optical observations
- GRB990510: X-ray afterglow
- GRB 990510 optical observations
- GRB990510: NFI X-ray source
- GRB 990506 Radio Observations
- GRB 990123, optical monitoring
- GRB 990506, optical observations
- GRB 990510: Final BeppoSAX-WFC Coordinates
- GRB 990506, Optical Observations
- GRB 990506 optical observations
- GRB 990506 optical observations
- GRB 990506, optical observations
- GRB990506 observation plan
- GRB 990506, optical observations from +1 to +3 hours
- GRB 990506, optical observations
- GRB990506 observation plan