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"27475 results found.
- GRB 990123: Detection of the IR Transient, and the Light Curve Fits
- GRB 990123: Continued Radio Observations
- GRB990123, Preliminary Lens Search Results
- GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
- GRB990123, ASCA X-ray observation of afterglow
- 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 optical observations
- GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
- GRB 990123 radio observations
- GRB 990123, new radio source
- GRB 990123: Optical Decay Slope
- GRB 990123 r-band photometry
- GRB990123, early optical counterpart detection
- GRB990123, BeppoSAX-NFI X-ray afterglow detection
- GRB990123, BeppoSAX WFC detection and NFI planned follow-up
- Optical Observations of GRB 981220
- GRB981220
- GRB 981220 Optical observations
- GRB 981226 Optical Observations
- GRB981226 Optical Observations
- GRB 981226
- GRB 981226 optical observations
- GRB981220 B, R and I band observations
- Optical Observations of GRB981226
- GRB 981220
- GRB 981220, radio observations
- GRB 980326/Host Galaxy
- GRB980425 Optical Follow-up
- GRB980703 Very Long Baseline Interferometry
- Optical Observations of the Host Galaxy of GRB 980519
- GRB980703 - BeppoSAX/GRBM detection
- GRB980703: Radio transient
- GRB 980703: Spectrum of the proposed optical counterpart
- 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 980613 optical observations
- GRB980613 Optical Observations
- GRB980613 BeppoSAX-NFI follow up
- GRB 980519 Optical Observations
- GRB 980519
- GRB980519 optical observations
- GRB980519 optical observations
- GRB980519 optical observations
- GRB980515, BeppoSAX IAUC to be submitted
- BSAX Observations of GRB980425 field
- SAX J0840.7+2248 Optical Observations
- GRB 980329 ROSAT observation
- GRB980326 X-ray Observations
- GRB980326, optical observations
- GRB980329, Fading IR counterpart to radio source
- GRB980329
- GRB980329 Keck K-band observations
- GRB980329 sub-millimeter observations
- GRB980329 near-IR observations
- GRB980329 optical observations
- GRB980329 optical observations
- GRB980329 VLA observations
- GRB980329 optical observations
- Near-IR follow-up on GRB 971227
- Optical Observations of the GRB 971227 field
- GRB971227: Plaskett R-band observations
- GRB 971227: Optical clarifications
- GRB971227: Further CAHA R-band images
- GRB 971227: CAHA R-band images
- GRB 971214: Redshift from Keck Optical Observations
- GRB 971214: KPNO Optical Observations