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"
32796 results found.
- Late-time HST/STIS Observation of GRB 990123
- GRB 990506 - clarification to GCN 352
- GRB 990506 - Optical Observations
- 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
- Late Afterglows of GRBs 990510, 990123
- X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
- X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
- X-ray/GRB 1SAX J0835.9+5118, Optical Observations
- GRB 990506 optical observation
- 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
- 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
- BeppoSAX: A new fast X-ray transient
- GRB 990510: optical observations
- GRB990510: photometric and spectroscopic observations with the VLT
- GRB 990510: optical linear polarization
- GRB 990510: optical observations
- GRB990510, VI observations
- GRB 990506 R band observations
- GRB990510: X-ray afterglow
- GRB 990510: optical observation
- VLT spectrum of GRB990510
- GRB 990510: Broad Band Break
- GRB 990510: BATSE Observations
- GRB 990510 Optical Observations
- GRB 990510, BVI photometry
- GRB 990510 optical observations
- GRB 990510: BeppoSAX/GRBM observations
- GRB990510 optical observations
- GRB 990510 optical observations
- GRB 990510 optical observations
- Galactic extinction towards GRB 990510
- GRB 990510 optical observations
- IPN localization of GRB990510
- GRB 990506 Radio Observations
- GRB 990123, optical monitoring
- GRB 990506: BATSE Observations
- 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
- Refined IPN error box for GRB990506
- GRB 990506: Limits on the possible optical transient
- GRB 990506, armchair astronomy
- GRB 990506, optical observations from +1 to +3 hours
- GRB 990506, optical observations
- GRB990506 observation plan
- New IPN/RXTE error box for GRB990506
- IPN localization for GRB990506
- GRB 970228: Redshift and properties of the host galaxy
- IPN localization of GRB990427
- GRB981220 VLBA observations
- GRB990321 REFINED IPN ANNULUS
- GRB990323 PRECISE IPN POSITION
- GRB990321 IPN TRIANGULATION
- GRB 990316 Optical Observations
- GRB 990316, Radio observations
- GRB 990316, Optical observations
- GRB990316, Optical observations
- GRB 990316 optical observations
- GRB990316: simultaneous optical observation
- ASM/IPN error box for GRB 990308 (BATSE #7457)
- GRB990308 not a new SGR
- GRB 990308a and GRB 990308b
- GRB990308 (Trig. 7457), optical observations
- GRB981220, IPN localization
- GRB 981220, radio observations
- GRB 990123, Field Photometry
- GRB 990217 Optical Observations
- GRB 990217, radio observations
- Optical Observations of GRB990217
- GRB990123: Caltech STIS Photometry and Images
- GRB990123 observations
- GRB990123, Optical Observation
- GRB 990123: Discovery of the Probable Host Galaxy
- GRB 990123: Reduced HST Images
- For Immediate Posting to GCN - HST Data GRB 990123 Available
- GRB19990123 observations
- GRB 990123: BVRI standards in the field
- GRB 990123: Updated Keck Spectroscopy Results
- GRB981220, field photometry
- GRB 990123 NOT Spectrum Update
- GRB990123, Optical observation
- GRB990123, is the "radio flare" due to an inhomogeneous medium?
- GRB 990123: Publicly available reduced HST images
- GRB990123, Upcoming HST Service Observations
- GRB 990123: New Constraints on Possible Foreground Galaxies
- GRB990123 Optical Observations