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"
- GRB 050129: a weak long GRB detected with INTEGRAL
- SGR1806-20: Swift-BAT detection of a large normal burst
- GRB050128: Faulkes Telescope South observations
- GRB 050124: Radio Observations
- GRB 050128: near-infrared observations with REM
- GRB050128,optical observations
- GRB 050126: A NIR afterglow candidate in the revised XRT error circle
- GRB050126: Updated Swift XRT Position
- SGR 1806-20: GMRT results at 240 MHz band.
- SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
- GRB 050126: Radio Observations
- GRB050128 Swift-BAT observations
- GRB 050128: Swift XRT prompt afterglow position
- HETE #3667: P60 Observations
- 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: Detection of NIR afterglow with Keck/NIRC
- GRB 050126: Prompt XRT detection and localization
- GRB 050124: NIR afterglow confirmed with Keck/NIRC
- GRB050124: No Swift UVOT Detection of Afterglow Emission
- GRB 050124, SMARTS optical/IR observations
- GRB 050117a: Radio Observations
- GRB 050124 I-band observation
- GRB 050124: NIR Candidates from Keck/NIRC
- GRB050124,optical observation
- GRB 050124 : Lulin R-band follow-up 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
- GRB 050123 : I-band follow-up observation
- GRB050123: optical limit 1.8h before GRB
- GRB050123,optical observation
- GRB 050123: KAIT observations
- GRB050123: P60 Observations
- GRB 050123(=H3666): A GRB Localized in Real Time by HETE
- CFHTLS optical transient unlikely to be a GRB
- Unusual optical transient (GRB ???)
- GRB050117a: Radio Observations
- GRB050117a: Refined analysis
- GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
- GRB050117: Palomar WIRC Ks-band 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
- SGR 1806-20: RXTE/PCA pulse frequency during flare
- Triangulation of Short Hard GRB050112 (large error box)
- SGR 1806-20: Further VLA Observations
- SGR 1806-20: Further low frequency GMRT results
- SGR 1806-20: Further VLA Observations
- SGR1806-20: Swift-BAT observations of two additional bursts
- SGR1806: Optical Transient Candidates in SOHO/LASCO Images
- Further VLA observations of SGR 1806-20
- SGR 1806-20 and extragalactic short-duration GRBs
- Further ATCA observations of SGR 1806-20
- Fourth Epoch VLA observations of SGR 1806-20
- SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
- SGR 1806-20: Temporal and Spectral behavior of radio transient
- ATCA observations of SGR 1806-20
- SGR 1806-20, RHESSI observations of the 041227 giant flare
- Third epoch observations of SGR 1806-20 with VLA
- Second Epoch VLA observations of SGR 1806-20
- Second-epoch VLA observations of SGR 1806-20
- SGR1806: Detection of a Sudden Ionospheric Disturbance
- DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
- VLA observations of SGR 1806-20
- SGR1806 VLA Observations
- VLA observations of SGR 1806-20
- SGR1806-20: RXTE-PCA observation of the 041227 super-flare
- GRB 041217: Optical observations
- SGR1806-20: Swift-BAT observation of the 041227 super-flare
- GRB041219, early time observations
- Detection of the SGR 1806-20 giant outburst back-scattered by the
- The giant outburst from SGR 1806-20
- IPN localization of giant flare from SGR1806-20
- Giant flare from SGR 1806-20 detected by INTEGRAL
- 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 041224: near-infrared observations with REM
- 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
- GRB 041219: TAROT optical observations
- GRB 041218: TAROT optical observations