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"26922 results found.
- Fermi GRB 251217A: Global MASTER-Net observations report
- GRB 251217A: Fermi GBM Final Real-time Localization
- GRB 251215A: Swift/UVOT Upper LImits
- GRB 251215A: Fermi GBM Observation
- Fermi GRB 251216A: Global MASTER-Net observations report
- GRB 251215A: COLIBRÍ optical upper limit
- GRB 251216A: Fermi GBM Final Real-time Localization
- EP251214b: KAIT optical upper limit
- Fermi GRB 251215A: Global MASTER-Net observations report
- EP251214a: Optical upper limit with Kinder observations
- GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
- GRB 251215A: Glowbug gamma-ray detection
- GRB 251214B: UAFO optical upper limit
- GRB 251213A: GRID-10B observation
- GRB 251214B: Swift-BAT refined analysis
- EP251214b: Global MASTER-Net observations report
- EP251214b : Einstein Probe detection of a fast X-ray transient
- EP251214b : Einstein Probe detection of a fast X-ray transient
- GRB 251214B: AbAO optical observations
- GRB 251209A: GECAM-B observation of a long burst
- GRB 251214D: GECAM-B observation of a long burst
- GRB 251214B: Fermi GBM Observation
- EP251214b (EP trigger 01709250023): LCO optical limits
- GRID detection of GRB 251213A
- GRB 251203B: AbAO optical observations
- GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 251214B: GECAM-B observation of a long burst
- GRB 251214B: Swift-XRT refined Analysis
- GRB 251213A: SVOM/GRM observation
- GRB 251213A: GECAM-B detection
- GRB 251214B: Swift/UVOT Detection
- GRB 251215A: Fermi GBM Final Real-time Localization
- GRB 251214B: COLIBRÍ observations of the afterglow
- EP251214a: EP-FXT non-detection and upper limit
- GRB 251214A: GECAM-B observation of a likely long burst
- GRB 251214B: 1.3m DFOT optical detection
- EP251214a: Global MASTER-Net observations report
- GRB 251214B: Xinglong-2.16m optical observation
- GRB 251214C: Fermi GBM Final Localization
- Fermi trigger No 787396657: Global MASTER-Net observations report
- GRB 251214B: SVOM/C-GFT optical observations
- EP251214a: COLIBRÍ optical upper limit
- Swift GRB 251214B: Global MASTER-Net observations report
- EP251214.305: COLIBRÍ optical upper limit
- GRB 251214B: Swift detection of a burst with an optical counterpart
- GRB 251214B: Fermi GBM Final Real-time Localization
- EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
- Fermi GRB 251214A: Global MASTER-Net observations report
- GRB 251214A: Fermi GBM Final Real-time Localization
- EP251212a: Global MASTER-Net observations report
- EP251212a / GRB 251212A: AstroSat CZTI detection
- EP251212a: EP-FXT follow-up observation
- GRB 251209A: NuSTAR detection of prompt emission
- EP251212a : COLIBRÍ optical upper limit
- EP251212a: Einstein Probe detection of an X-ray transient
- Fermi GRB 251211B: Global MASTER-Net observations report
- GRB 251211B: Fermi GBM Final Real-time Localization
- IceCube-251210A: DDOTI Optical Upper Limit
- SVOM GRB251211.12: Global MASTER-Net observations report
- GRB 251211A: Fermi GBM Final Real-time Localization
- GRB 251209A: Fermi GBM observation
- GRB 251205A: 1.3m DFOT optical upper limit
- IceCube Alert 251210.46: Global MASTER-Net observations report
- EP251130a: Mondy and AbAO optical observations
- Fermi GBM Sub-Threshold Detection of GRB 251205A
- GRB 251208B: COLIBRÍ optical upper limits
- EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
- GRB 251208C: GECAM-B observation of a short burst
- GRB 251208A: GECAM-B observation of a short burst
- Fermi GRB 251209A: Global MASTER-Net observations report
- Fermi GRB 251208C: Global MASTER-Net observations report
- GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 251209A: Fermi GBM Final Real-time Localization
- GRB 251208B: Fermi GBM Observation
- GRB 251208B: GROWTH-India Telescope optical upper limits
- GRB 251205A: J-band detection with WINTER
- GRB 251208D: Swift-XRT observations
- GRB 251208A: SVOM/GRM observation of a short burst
- GRB 251208C: SVOM/GRM observation of a short burst
- LAT GRB251208.43: Global MASTER-Net observations report
- GRB 251205A: Liverpool Telescope further optical follow-up observations
- GRB 251208D: LCO optical upper limits
- SVOM GRB251208D: Global MASTER-Net observations report
- GRB 251208B: Fermi-LAT detection
- GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
- GRB 251208D: SVOM possible detection of a faint burst
- GRB 251206A: SVOM detection of a burst through offline search
- GRB 251208C: Fermi GBM Final Real-time Localization
- GRB 251205A : MITSuME Akeno optical afterglow candidate detection
- GRB 251208B: Fermi GBM Final Real-time Localization
- GRB 251208A: Fermi GBM Final Real-time Localization
- EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
- GRB 251205A: Liverpool Telescope further optical follow-up observations
- SVOM GRB251206.86: Global MASTER-Net observations report
- EP-WXT trigger 01709249380: confirmation of a stellar flare by BOOTES-5
- The EP-WXT trigger 01709249380 is likely a flaring star
- GRB 251205A: GROWTH-India Telescope optical observations
- GRB 251205A: Swift-BAT refined analysis
- GRB 251205A: Swift-XRT refined Analysis
- GRB 251205A: Swift/UVOT Detection