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"11528 results found.
- GRB 251121A: Fermi GBM Final Real-time Localization
- Fermi Gamma-ray Burst Monitor trigger 785388351 / 251121143 is not a GRB
- Fermi trigger No 785388351: Global MASTER-Net observations report
- GRB 251118A: Swift/UVOT Detection
- GRB 251118A: Glowbug gamma-ray detection
- GRB 251118A: Fermi GBM Observation
- GRB 251118A: Swift-XRT afterglow detection
- GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
- GRB 251118A: GECAM-B detection
- GRB 251118A: NuSTAR detection of bright prompt emission
- GRB 251117A: Swift-XRT observations
- GRB 251117A: Insight-HXMT/HE detection
- GRB 251118A: Fermi-LAT detection
- GRB 251118A: Swift ToO observations
- Fermi GRB 251118B: Global MASTER-Net observations report
- GRB 251118B: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
- GRB 251118A: BALROG localization (Fermi Trigger 785190695 / GRB 251118855)
- GRB 251117A: FTW Observations of Swift candidate X-ray sources
- GRB 251118A: Fermi GBM Final Real-time Localization
- GRB 251117A: AstroSat CZTI detection
- GRB 251114B: Insight-HXMT/HE detection
- GRB 251114B: GECAM-B detection of a short burst
- GRB 251117A: Fermi GBM observation
- GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
- GRB 251115A: Swift-XRT observations
- GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
- GRB 251117A: SVOM/GRM observation of a short burst
- GRB 251117A: Tiled Swift observations
- GRB 251117A: Fermi-LAT detection
- GRB 251117A: Fermi GBM Final Localization Correction
- GRB 251116A: Fermi GBM Final Real-time Localization
- GRB 251115A: Tiled Swift observations
- GRB 251115A: Fermi-LAT detection
- GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
- Fermi GRB 251115A: Global MASTER-Net observations report
- GRB 251115A: Fermi GBM Final Real-time Localization
- GRB 251113A: Glowbug gamma-ray detection
- GRB 251113A: AstroSat CZTI detection
- GRB 251114B: Fermi GBM Final Real-time Localization
- Fermi trigger No 784717756: Global MASTER-Net observations report
- Konus-Wind detection of GRB 251103A
- Fermi GRB 251114A: Global MASTER-Net observations report
- GRB 251114A: Fermi GBM Final Real-time Localization
- Fermi GRB 251113A: Global MASTER-Net observations report
- GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
- GRB 251113A: Fermi GBM Final Real-time Localization
- Fermi Gamma-ray Burst Monitor trigger 784717756/251113381 is not a GRB
- Fermi Gamma-ray Burst Monitor trigger 784687703/251113034 is not a GRB
- Fermi Gamma-ray Burst Monitor trigger 784687099/251113027 is not a GRB
- LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
- Fermi trigger No 784621743: Global MASTER-Net observations report
- Fermi Gamma-ray Burst Monitor trigger 784653403/251112637 is not a GRB
- GRB 251013C: Chandra X-ray observations and jet break detection
- GRB 251105B: Insight-HXMT/HE detection
- GRB 251105A: AstroSat CZTI detection
- GRB 251108A: Fermi GBM Final Localization Correction
- Fermi trigger No 784329591: Global MASTER-Net observations report
- Fermi trigger No 784279167: Global MASTER-Net observations report
- GRB 251102B: SVOM/GRM observation
- Fermi Gamma-ray Burst Monitor trigger 784279167/251108305 is not a GRB
- IPN triangulation of GRB 251105B (possible sGRB with EE)
- GRB 251106A: Kilonova-Catcher optical upper limit
- Fermi GBM Sub-Threshold Detection of GRB 251106A
- GRB 251103B: AstroSat CZTI detection
- GRB 251025C: TERI Gamma-ray detection
- GRB 251016B: TERI Gamma-ray detection
- GRB 251016A: TERI Gamma-ray detection of a short burst
- GRB 250920C: TERI Gamma-ray detection
- Fermi trigger No 784034269: Global MASTER-Net observations report
- Fermi Gamma-ray Burst Monitor trigger 784109140/251106337 is not a GRB
- GRB 251105A: Fermi GBM Observation
- GRB 251105C: Fermi GBM Final Localization Correction
- GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
- GRB 251105B: AstroSat CZTI detection of a short burst with extended emission
- GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
- Fermi GBM Sub-Threshold Detection of GRB 251105B
- Fermi GRB 251105A: Global MASTER-Net observations report
- GRB 251105A: Fermi GBM Final Real-time Localization
- Fermi Gamma-ray Burst Monitor trigger 783986701/251104920 is not a GRB
- GRB 251103B: Fermi GBM observation
- GRB 251028A: Insight-HXMT/HE detection
- GRB 251103A: WFST optical observations
- GRB 251103A: OHP/T193 optical observations
- GRB 251103A: Xinglong 2.16m optical detection
- GRB 251103A: Insight-HXMT detection
- GRB 251103A: KAIT optical observations
- GRB 251103B: Nanshan/HMT optical upper limit
- GRB 251013C: 7DT detection and Medium-band SED of Afterglow
- GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 251103B: MITSuME Akeno optical upper limits
- Fermi GRB 251103A: Global MASTER-Net observations report
- GRB 251103A: J-band detection with WINTER
- GRB 251103B: GROWTH-India Telescope optical upper limits
- GRB 251103A: Kilonova-Catcher optical afterglow detection
- GRB 251103B: Fermi GBM Final Real-time Localization
- GRB 251103A: Fermi GBM Observation
- GRB 251103A: SVOM/GRM observation
- GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 251103A: GOTO optical afterglow detection