GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"- GRB 240825A: Swift detection of a burst with a bright optical counterpart
- GRB 240825A: Fermi GBM Final Real-time Localization
- GRB 240824A: Swift-BAT refined analysis
- GRB 240824A: SVOM/C-GFT optical upper limit
- GRB 240824B: Swift-XRT afterglow detection
- GRB 240824A: Swift-XRT observations
- LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate
- GRB 240824B: Swift/BAT arcminute localization of a burst
- GRB 240824B: Swift ToO observations
- Fermi GRB 240824C: Global MASTER-Net observations report
- GRB 240824C: Fermi GBM Final Localization
- GRB 240824A: Swift/UVOT Upper Limits
- GRB 240821A: Swift/UVOT observations of the XRT sources.
- GRB 240824B: MAXI/GSC detection
- GRB 240824B: Fermi GBM Final Real-time Localization
- GRB 240824A: Retraction of GCN 37255
- GRB240824A: GRANDMA/TAROT-TCA Upper Limit
- SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
- GRB 240824A: KAIT optical upper limit
- GRB 240824A: Skynet Optical Afterglow Discovery
- GRB 240824A: Swift detection of a burst
- Swift GRB240824.04: Global MASTER-Net observations report
- SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
- GRB 240821A: Colibri Optical Upper Limit
- EP240820a: PRIME J-band Observations
- GRB 240821A: Swift-XRT observations
- GRB 240822A: AstroSat CZTI detection of a short burst
- GRB 240821A: REM optical/NIR upper limits
- GRB 240821A: LCO optical observations
- GRB 240821A: JinShan optical upper limits
- GRB 240809A: Mondy and AbAO Optical Observations
- GRB 240821A: SVOM/VT follow-up and optical upper limit
- GRB 240821A: GMG Optical Upper Limit
- Fermi GRB 240821A: Global MASTER-Net observations report
- GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
- GRB 240821A: Fermi GBM Observation
- Fermi trigger No 745964969: Global MASTER-Net observations report
- Fermi trigger No 745925274: Global MASTER-Net observations report
- GRB 240821A: Swift ToO observations
- Fermi trigger No 746019401: Global MASTER-Net observations report
- Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
- Fermi trigger No 745935375: Global MASTER-Net observations report
- GRB240821A: EIRSAT-1 GMOD Detection
- GRB240821B: First GRB Detected by EIRSAT-1 GMOD
- GRB 240821A: EP-FXT follow-up observation and afterglow candidates
- Fermi GRB 240821B: Global MASTER-Net observations report
- EP240801a: Keck/LRIS spectroscopic redshift confirmation
- GRB 240821A: SVOM/GRM observation
- GRB 240821A: SVOM/GRM observation
- GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
- GRB 240821B: Fermi GBM Final Localization
- Fermi trigger No 745866488: Global MASTER-Net observations report
- Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
- GRB 240821A: BALROG localization (Fermi Trigger 745958167 / GRB 240821775)
- GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
- GRB 240821A: Fermi GBM Final Real-time Localization
- GRB 240819A: Swift-XRT observations
- GRB 240819A: JinShan optical upper limits on one Swift/XRT source
- GRB 240820B: SVOM/GRM observation
- EP240820a: TRT optical upper limit
- EP240820a: EP detection of a fast X-ray transient
- GRB 240819A: KAIT optical upper limit
- EP240816a: PRIME upper limits
- Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
- Fermi trigger No 745873283: Global MASTER-Net observations report
- Fermi trigger No 745871958: Global MASTER-Net observations report
- GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
- GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
- GRB 240819A: X-ray follow-up observation with EP-FXT
- Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
- GRB 240820A: Fermi GBM Final Real-time Localization
- GRB 240819A: Swift ToO observations
- GRB 240814A: SVOM/GRM observation
- EP240816b: Liverpool Telescope optical follow-up observations
- GRB 240814C: SVOM/GRM observation
- EP240816a: BOOTES-6/DPRT optical upper limit
- GRB 240815A: SVOM/GRM observation
- GRB 240817A: Fermi GBM Final Real-time Localization
- Integral GRB240816.79: Global MASTER-Net observations report
- IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
- GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
- IBAS Alert n.10856: not a GRB
- GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
- EP240816b: KAIT optical upper limit
- GRB 240814B: GRBAlpha detection
- Fermi trigger No 745501396: Global MASTER-Net observations report
- EP240816a: EP detection of a fast X-ray transient and follow-up observation
- EP EP240816b: Global MASTER-Net observations report
- EP240816b: TRT optical upper limit
- EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
- Fermi GRB 240814A: Global MASTER-Net observations report
- Fermi GRB 240814C: Global MASTER-Net observations report
- Fermi trigger No 745306088: Global MASTER-Net observations report
- GRB 240814C: Fermi GBM Final Real-time Localization
- Fermi GRB 240814B: Global MASTER-Net observations report
- GRB 240812B: SVOM/GRM observation
- EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
- GRB 240814B: Fermi GBM Final Real-time Localization
- GRB 240814A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S240813d: Updated Sky localization