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"19260 results found.
- GRB 050124: K-band afterglow observations
- GRB050126: MASTER optical limit for KECK OT
- GRB050126: Burst Parameters Measured by BAT
- GRB050126: MASTER optical observations
- GRB 050126: Prompt XRT detection and localization
- GRB050124: No Swift UVOT Detection of Afterglow Emission
- GRB 050117a: Radio Observations
- GRB050124,optical observation
- GRB050124: Updated Swift XRT Position and Fluxes
- GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
- GRB050124: Refined BAT position, spectral and fluence information
- GRB050124: Swift-BAT position of a double-peaked burst
- GRB050117a: Radio Observations
- GRB050117a: Refined analysis
- GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
- GRB050117b: Swift-BAT detection of a weak burst
- GRB050117: optical observation
- GRB 050117, I-band observations
- GRB 050117: Optical observation
- GRB050117: Refined XRT position
- GRB050117: MASTER optical observations
- MASTER:GRB050117 SWIFT
- GRB050117: Swift-BAT detection of a long multi-peaked burst
- GRB050117: Swift XRT Position
- SGR1806-20: Swift-BAT observations of two additional bursts
- SGR 1806-20, RHESSI observations of the 041227 giant flare
- SGR1806-20: RXTE-PCA observation of the 041227 super-flare
- GRB 041217: Optical observations
- SGR1806-20: Swift-BAT observation of the 041227 super-flare
- GRB041228: ROTSE-III Optical Observations
- GRB041228: Swift-BAT detection of a burst
- GRB041219; RXTE ASM Observations
- NIR Observations of GRB 041219
- GRB041226: ROTSE-III Optical Observations
- GRB041226: Swift-BAT detection of a burst
- GRB041223: decay of the afterglow
- GRB041224: ROTSE-III Optical Observations
- GRB 041223: XRT afterglow spectrum and light curve
- GRB 041223 Fluence measured by Swift-BAT
- GRB041224: Swift-BAT detection of a soft burst
- GRB041223: optical and NIR observations with REM
- Swift-BAT Time History of GRB041219
- GRB041223: Swift XRT Detection of X-ray Afterglow Emission
- GRB041223: ROTSE-III Optical Observations
- GRB041223: Swift-BAT detection of a bright long burst
- GRB041220: Swift-BAT burst
- GRB 041219 Optical Observations
- GRB041219c: Third Burst in One Day from Swift-BAT
- GRB041219b: A Swift-BAT burst
- Swift-BAT detection of the bright long burst GRB041219
- GRB041217: optical limit 30 min after GRB
- GRB041217: Optical Observations
- GRB041217: NIR and optical observations with REM
- GRB041217: P60 Optical Observations
- GRB041217: Infrared Observations
- GRB041217: The First GRB Located On-Board Swift
- GRB040916: Optical observations
- GRB040422: optical and NIR observations at the VLT
- GRB040223, improved XMM position
- SN 2003jd (SN/GRB?) - possible association with GRB 030929