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.
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"26509 results found.
- GRB 260421B: SVOM/VT optical observations
- EP260416a: J band upper limit by SYSU 80cm infrared telescope
- GRB 260310A: Late-time Chandra X-ray Detection
- GRB 260418A: Insight-HXMT/HE detection
- GRB 260415A: CALET Gamma-Ray Burst Monitor detection
- GRB 260415B: CALET Gamma-Ray Burst Monitor detection
- GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
- GRB 260421B: BOOTES-7 early optical afterglow detection
- GRB 260421B: LCO optical afterglow confirmation
- GRB 260421B: SVOM/COLIBRÍ (FM-GFT) optical detection of a candidate counterpart
- GRB 260421B: TRT optical counterpart detection
- GRB 260421B: SVOM detection of a long burst
- GRB 260412A: LCOGT Optical Upper Limits
- GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
- EP260416a: 1.5m OSN and 2.2m CAHA optical monitoring
- GRB 260417A: SVOM/GRM observation
- EP260321A/AT2026gzf: Optical observation from 1.3m DFOT
- EP260417a: GROWTH-India Telescope optical upper limit
- EP260417b: GROWTH-India Telescope optical upper limit
- EP260416a: VLT/FORS2 spectroscopic redshift confirmation
- EP260417a/GRB 260417A: refined analysis of the EP-WXT and follow-up EP-FXT observations
- Konus-Wind detection of GRB 260411B
- GRB 260417A: AstroSat CZTI detection
- IPN triangulation of GRB 260411B
- EP260416a: LCO observations confirm end of flaring phase
- EP260324a / AT2026hir: Further multiband optical follow-up with the PKU 60cm Telescope
- EP260417a: TRT optical counterpart detection
- EP260417a: Einstein Probe detection of an X-ray transient
- EP260416a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260417b: Einstein Probe detection of a fast X-ray transient
- EP260416a: KAIT optical upper limit
- GRB 260414A: Insight-HXMT/HE detection
- EP260416a: COLIBRÍ confirmation of the optical rebrightening
- EP260416a: WFST optical observations and rebrightening
- EP260416a: SVOM/VT optical observation
- GOTO26djh/AT2026jpw: SVOM/VT optical observation
- GRB 260415B: Glowbug gamma-ray detection
- GRB 260411B: Glowbug gamma-ray detection
- GRB 260415A: Insight-HXMT/HE detection
- EP260416a: COLIBRÍ optical counterpart candidate
- COLIBRI optical observations of the transient GOTO26djh/AT2026jpw
- EP260416a: Einstein Probe detection of an X-ray transient
- GOTO26djh/AT2026jpw : MASTER OT observation
- GRB 260415B: NuSTAR detection of long prompt emission
- GOTO discovery of fast-fading transient GOTO26djh/AT2026jpw, a candidate orphan afterglow
- GRB 260414A: Glowbug gamma-ray detection
- EP260409a: Early NIR limits from MIRAGE on the MDM 1.3m telescope
- GRB 260412A: Insight-HXMT/HE detection
- GRB 260410A: Glowbug gamma-ray detection of a short burst
- GRB 260410B: Insight-HXMT/HE detection
- GRB 260410A: Insight-HXMT/HE detection
- Konus-Wind detection of GRB 260410A (short/hard)
- GRB 260411B: GECAM-B observation of a long burst
- EP260321a: SVOM/VT optical observations and color changes around peak
- GRB 260410A: CALET Gamma-Ray Burst Monitor detection
- GRB 260412A: GECAM-B observation of a long burst
- GRB 260412A: Fermi GBM Observation
- GRB 260310A / AT2026fgk: NuSTAR detection of the rebrightening
- GRB 260411B: Fermi-LAT detection
- GRB 260412A: SVOM detection of a long burst
- GRB 260411B: COLIBRÍ optical observations
- GRB 260410B: Fermi GBM Observation
- GRB260411B: 3.6m DOT optical observation
- GRB 260411A: SVOM/GRM observation
- GRB 260407B: SVOM/GRM detection of a possible magnetar X-ray burst
- GRB 260411B: SVOM/GRM observation of a long burst
- GRB 260409A: Insight-HXMT/HE detection
- GRB 260411B: Fermi GBM Detection
- GRB 260411B: GOTO optical counterpart candidate
- GRB 260410A: COLIBRÍ optical upper limit
- GRB 260410A: Fermi GBM Observation
- GRB 260410B: SVOM/GRM detection of a short faint burst
- GRB 260410A: Fermi-LAT detection
- EP260409a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- GRB 260310A/AT2026fgk: Kilonova-Catcher SN peak identification
- GRB 260407A: GECAM-A detection
- GRB 260407A: Insight-HXMT/HE detection
- EP260409a: SVOM/VT optical upper limits
- EP260409a: COLIBRÍ optical upper limits
- GRB 260407A: CALET Gamma-Ray Burst Monitor detection
- EP260409a: Einstein Probe detection of an X-ray transient
- GRB 260407A: Glowbug gamma-ray detection
- GRB 260402A: SVOM/ECLAIRs refined analysis
- GRB 260310A / AT2026fgk: X-ray rebrightening
- EP260402a / GRB 260402A: Mephisto optical upper limits
- EP260403a: Mephisto optical upper limits
- EP260402a/GRB 260402A: Xinglong optical upper limit
- EP260321a: Upper limits from VLA radio observations
- GRID detection of GRB 260401A
- EP260321a: uGMRT observations
- EP260405a: SVOM/VT optical upper limits
- EP260405a: Einstein Probe detection of a fast X-ray transient
- EP260405a / EP-WXT 11900672904: COLIBRÍ optical upper limits
- GRB 260403A: GECAM-B observation of a long burst
- EP260403a: refined analysis of the EP-WXT and EP-FXT observations
- GRB 260330B: SVOM/VT further optical observation
- GRB 260330B: SVOM/ECLAIRs refined analysis
- EP260403a: LCO optical observations of the counterpart
- GRB 260310A/AT2026fgk: Kilonova-Catcher long term optical monitoring
- EP260403a: LCO optical counterpart detection