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"27774 results found.
- GRB 990915 optical observations
- GRB990908, another BeppoSAX-GRBM/WFC burst detection
- GRB 990806 Optical observations
- BeppoSAX NFI Observation of GRB990705
- BeppoSAX NFI Observation of GRB990705
- Updated Astrometry for the IR Counterpart of GRB990705
- Infrared and Optical Observations of GRB990705
- GRB990704, optical observations
- GRB990704: BeppoSAX detection
- GRB 990506 - clarification to GCN 352
- GRB 990506 Radio Transient
- X-ray/GRB 1SAX J0835.9+5118, Optical Observations
- X-ray/GRB 1SAX J0835.9+5118, Optical Observation
- radio detection of X-ray/GRB transient
- GRB 990506 R band observations
- GRB 990506: BATSE Observations
- GRB 990506, optical observations
- GRB 990506, optical observations from +1 to +3 hours
- GRB990321 IPN TRIANGULATION
- GRB 990316 Optical Observations
- ASM/IPN error box for GRB 990308 (BATSE #7457)
- GRB 990123: Discovery of the Probable Host Galaxy
- GRB19990123 observations
- GRB 990123 NOT Spectrum Update
- 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
- GRB 990123: Continued Radio Observations
- GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
- GRB 990123 Optical Follow-Up
- GRB 990123; Addendum to GCN 223
- GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
- GRB 990123 Optical Follow-Up
- GRB 990123: Possible Gravitationally Lensed Burst?
- GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
- GRB 990123 radio observations
- GRB990123, early optical counterpart detection
- GRB990123, BeppoSAX-NFI X-ray afterglow detection
- GRB990123, BeppoSAX WFC detection and NFI planned follow-up
- GRB981220
- GRB 981220 Optical observations
- GRB 981226 Optical Observations
- GRB 981226
- GRB 981226 optical observations
- GRB981220 B, R and I band observations
- Optical Observations of GRB981226
- GRB 981220
- GRB 980326/Host Galaxy
- Optical Observations of the Host Galaxy of GRB 980519
- GRB980703 - BeppoSAX/GRBM detection
- RXTE Observation of GRB 980706
- GRB980703: LOTIS observation at early times
- GRB980613 Optical Observations
- GRB 980703 H-band Observations
- GRB980703 optical followup
- GRB 980613: Detection of the probable host galaxy
- GRB 980613 optical observations
- GRB 980519 Optical Observations
- GRB980519 optical observations
- GRB980519 optical observations
- GRB980519 optical observations
- BSAX Observations of GRB980425 field
- GRB 980329 ROSAT observation
- GRB980326, optical observations
- GRB980329
- GRB980329 Keck K-band observations
- GRB980329 optical observations
- Optical Observations of the GRB 971227 field
- GRB971227: Further CAHA R-band images
- GRB 971227: CAHA R-band images
- GRB 971214: Redshift from Keck Optical Observations
- GRB 971214: KPNO Optical Observations