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"15251 results found.
- GRB 050123 : I-band follow-up observation
- Unusual optical transient (GRB ???)
- GRB050117: optical observation
- GRB050117: Refined XRT position
- GRB050117: Swift XRT Position
- SGR 1806-20: RXTE/PCA pulse frequency during flare
- SGR 1806-20: Further low frequency GMRT results
- SGR1806: Optical Transient Candidates in SOHO/LASCO Images
- SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
- SGR 1806-20, RHESSI observations of the 041227 giant flare
- Second Epoch VLA observations of SGR 1806-20
- Second-epoch VLA observations of SGR 1806-20
- SGR1806: Detection of a Sudden Ionospheric Disturbance
- VLA observations of SGR 1806-20
- VLA observations of SGR 1806-20
- SGR1806-20: RXTE-PCA observation of the 041227 super-flare
- GRB 041217: Optical observations
- The giant outburst from SGR 1806-20
- IPN localization of giant flare from SGR1806-20
- NIR Observations of GRB 041219
- GRB041223: decay of the afterglow
- GRB 041223 Fluence measured by Swift-BAT
- GRB041223: optical and NIR observations with REM
- Swift-BAT Time History of GRB041219
- GRB 041223: J-band observations of the afterglow
- GRB041223: Swift-BAT detection of a bright long burst
- Very high activity of SGR 1806-20
- GRB 041219: WSRT Radio Afterglow Detection
- GRB 041218: Optical observations
- GRB 041219 : optical follow-up observations
- GRB041219: Continued NIR Observations
- GRB 041219 ,optical observation
- GRB 041219: Radio Afterglow Detection
- GRB 041218 : Radio Observations
- GRB 041218: R-band optical observations
- GRB041218: optical observations
- GRB041219: Confirmed NIR Afterglow
- GRB 041218: Optical Observation
- GRB 041219: Infrared Afterglow Candidate
- GRB 041219: Infrared Afterglow Candidate
- GRB041218: optical observations
- GRB041217: P60 Optical Observations
- Optical Transient in Lynx not a GRB
- GRB041211: Ashra Prototype optical observation
- GRB041211, Faulkes Telescope optical observation
- GRB041211,optical observation
- GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
- GRB 041006: Optical Observations
- GRB041006: RTT150 Optical Observations
- GRB041006: RTT150 Optical Observations
- GRB041016,optical observation
- GRB 041016: Optical limits
- GRB041015,optical observation
- GRB041006: Fading X-ray Afterglow Observed with Chandra
- GRB 041006 R observations in Loiano
- GRB 040924: VLT spectroscopy
- Search for SN light in XRF 040912 with MEGACAM
- GRB 041006 Optical afterglow observations
- IBAS GRB Alert # 2010
- GRB 041006: BR observations with VATT
- GRB 041006 : optical follow-up observation at Lulin Observatory
- GRB 041006 : Optical follow-up observation at TAROT
- GRB041006: Optical photometry and spectroscopy at TNG
- GRB041006 (=HETE3570): optical observations
- ROTSE-IIIa Observations of GRB 041006
- GRB041006, optical observation
- GRB041006, submillimetre observations
- GRB041006,optical observation
- GRB 041006 : Optical follow-up observation at KISO
- GRB 041006: Finding chart
- Bursts from SGR 1806-20: Preliminary INTEGRAL results
- SGR 1806-20 still active
- GRB040929,optical observation
- Konus-Wind and Helicon-Coronas-F observations of GRB040924
- GRB040924, RTT150 optical observation
- GRB040924: KAIT observations
- GRB040924: Afterglow magnitude at t=17.5hr
- GRB040924 : Optical candidate observations at Lulin observatory
- GRB040924 : Optical candidate observations at Lulin observatory
- GRB 040924, optical follow-up
- IPN triangulation of GRB040924 (H3564)
- GRB040912(=H3557): Chandra Candidate X-ray Afterglow
- XRF040916: continuing decay of OT
- GRB040912(=H3557): Candidate Optical Afterglow
- XRF040916, optical observations
- XRF 040912 (=H3557): Spectral and Temporal Properties
- XRF040916: optical follow-up observations
- GRB040916: Archival optical observations
- GRB040912(=H3557): Observations with the Chandra X-ray Observatory
- GRB040916: Optical observations
- ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
- GRB040912 (= H3557): Chandra Observations Scheduled
- GRB 040912, BVRI observations
- Optical observations of field of GRB040912
- GRB040903 - A XRF?
- ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
- Possible GRB 040903 detected with INTEGRAL
- XMM-Newton Images of GRB 040827
- GRB 040827: K imaging - no evidence of variability
- GRB 040827: Detection of NIR afterglow