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"
- GRB001109, Host Galaxy Spectroscopic Observations
- Probable SGR or Short Duration GRB Detected by HETE
- GRB000926 Host Galaxy Observations
- GRB 010222: HST observations -- host galaxy and late-time decay
- BeppoSAX/GRBM detection of GRB 010801
- GCN and HETE status
- Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
- BeppoSAX/GRBM detection of GRB010728
- GRB 010222 - WHT BVRI images
- SGR1900+14 burst seen by HETE: BeppoSAX data
- GRB 010629 Optical Observations
- GRB010629: Optical Observations
- SGR1900+14: High Fluence Burst Localized by HETE
- GRB010629, optical observations
- IPN triangulation of GRB010629
- GRB010629: A Burst Localized by HETE
- SGR1900+14: Second Burst Localized by HETE
- SGR1900+14: A Burst Localized by HETE
- Possible burst from SGR1806-20
- IPN detection of SGR1900+14
- SGR1806-20: A Second, Intense Burst Localized by HETE
- GRB 00630: Host Galaxy
- SGR1806-20: Localization by HETE
- IPN triangulation of GRB010613
- IPN triangulation of GRB010612
- IPN triangulation of GRB010612
- HETE Fully-Automated GCN Notices
- GRB000301C: Late-time HST/STIS observation
- GRB010518: a faint BeppoSAX detection
- GRB000418: HST/STIS Second-epoch Observations
- X-ray precursors to the large flare from SGR 1900+14
- GRB010214, optical observations
- GRB010427, Gamma Ray Observations
- SGR 1900+14: No evidence of extended X-ray emission
- SGR 1900+14 : RXTE observations
- BeppoSAX/NFI Follow-up Observation of SGR 1900+14
- SGR1900+14 - correction
- SGR1900+14
- SGR 1900+14: Correction to GCN 1049
- GRB 010222 /corrections to VBT data
- Millimeter observation of SGR 1900+14
- SGR 1900+14: Detection of extended X-ray emission
- Chandra Observations of SGR 1900+14
- SGR 1900+14, Chandra observations
- Chandra Observations of SGR 1900+14
- Possible precursor to the SGR1900+14 giant burst
- SGR1900+14, I-band observations
- IPN Triangulation of the Giant Flare from SGR1900+14
- GRB010412, field photometry
- Giant flare from SGR1900+14
- GRB 010326b Optical Observations
- GRB010412: Optical observations
- GRB010412: Optical observations
- GRB010412: BeppoSAX GRBM and WFC observations
- IPN Triangulation of GRB010412
- GRB010412: refined positions from BeppoSAX
- BeppoSAX GRB: extension of BSAX operations upto April 30, 2002
- BeppoSAX GRB ALERT: GRB010412
- GRB Observation Report
- GRB010324, revised field photometry
- REVISED LOCATION OF GRB010326A
- GRB 980326: Late-time HST/STIS observations
- GRB010324, field photometry
- GRB010326B, field photometry
- GRB010326, field photometry
- GRB010220, field photometry
- Further Optical Observations of GRB 010324
- GRB010222, CXO X-ray observations
- GRB 010326A: Further optical observations
- GRB010324: BeppoSAX/GRBM data
- GRB 010326B: Optical observations
- GRB010324, optical observations
- GRB010326B: Localization by HETE (2nd GRB for this date)
- GRB 010326: Optical observations
- GRB 010326 optical observations
- GRB010326: Refined Localization by HETE
- GRB010326: Localization by HETE
- Duration, ECT, peak flux and fluence of GRB010324
- Optical Observations of GRB 010324
- IPN TRIANGULATION OF GRB010324
- GRB990705, VLT-FORS1 observations of the host galaxy
- GRB010222, late-time optical observation
- Support extension to the BeppoSAX mission
- GRB 010222 - HEGRA GeV/TeV Observations
- Congratulate Scott on the 1000th GRB Coordinates Network Circular!
- GRB010222: Chandra X-ray Observatory Observation
- GRB010222: Sub-millimeter vanishing act
- GRB010222 - Optical observation
- GRB 010222, Optical Observations
- GRB010220 optical obsercations
- GRB010222 - Optical observation
- GRB 010222: High-Resolution Keck Spectroscopy
- GRB010222: Optical observation and decay
- GRB 010214, I-band data
- Sub-millimeter Excess/GRB 010222
- GRB 010222
- GRB 010222 HST/Chandra TOO
- GRB 010222
- GRB010222 further R-band photometry
- GRB010222: R-band data