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"23399 results found.
- GRB 990705, R-band observations
- Updated IPN localization of GRB990705
- IPN localization of GRB990704
- IPN localization of GRB990705
- Infrared and Optical Observations of GRB990705
- GRB 990705, radio observations
- GRB990704: SAX-NFI results summary
- GRB990704 radio and optical observations
- GRB990704
- GRB990704, optical observations
- BeppoSAX NFI Observation of GRB990627 X-ray afterglow
- Optical Observations of GRB990627
- GRB 990627, radio observations
- GRB990627: BeppoSAX-WFC final location
- Late-time HST/STIS Observation of GRB 990123
- Optical Observations of GRB 990506
- GRB990527 Optical Observations
- X-ray/GRB 1SAX J0835.9+5118, Optical Observation
- 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
- 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
- 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: Broad Band Break
- GRB990510 optical observations
- GRB 990510 optical observations
- IPN localization of GRB990510
- 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 from +1 to +3 hours
- GRB 990506, optical observations
- GRB990506 observation plan
- IPN localization for GRB990506
- GRB 970228: Redshift and properties of the host galaxy
- GRB 990316 Optical Observations
- GRB 990316, Radio observations
- GRB 990316 optical observations
- GRB990316: simultaneous optical observation
- ASM/IPN error box for GRB 990308 (BATSE #7457)
- GRB990308 (Trig. 7457), optical observations
- GRB981220, IPN localization
- GRB 990123, Field Photometry
- GRB 990217 Optical Observations
- GRB 990217, radio observations
- BATSE Flight Anomaly
- GRB990123 observations
- GRB990217, WFC position
- GRB990123, Optical Observation
- GRB 990123: Discovery of the Probable Host Galaxy
- GRB19990123 observations
- GRB 990123: BVRI standards in the field
- GRB981220, field photometry
- GRB990123, Optical observation
- GRB990123, Upcoming HST Service Observations
- GRB990123, 15-GHz limits
- GRB 990123: New Constraints on Possible Foreground Galaxies
- GRB990123 Optical Observations
- GRB990123, Probability of gravitational lensing
- GRB 990123: Detection of the IR Transient, and the Light Curve Fits
- GRB990123, Preliminary Lens Search Results
- On the Lensing Interpretation of GRB 990123
- Search for Potential Images of GRB 990123
- GRB990123, Optical BVRI Observations
- GRB 990123: near-infrared observations.
- GRB990123, OSSE observations
- GRB990123: NIR Observation
- "GRB 990123: New BV Observations"
- GRB990123 IPN annulus
- GRB 990123 Spectroscopic Redshifts
- GRB 990123: New Optical Observations, Decay Measure
- GRB 990123 Optical Follow-Up
- GRB 990123: Possible Gravitationally Lensed Burst?
- GRB990123, optical observation
- GRB 990123 optical observations
- GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
- GRB 990123 radio observations
- GRB 990123: Optical Decay Slope
- GRB 990123 r-band photometry
- GRB 990123 Optical Follow-up
- GRB990123, early optical counterpart detection
- GRB990123 Optical Observation
- Possible identification of SN1999E with GRB980910