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"32548 results found.
- GRB 260601A: GECAM-B observation of a short burst
- GRB 260601B/EP260601a: J-band upper limit with WINTER
- EP260530a/AT 2026nwl: COLIBRÍ optical follow up
- EP260530a/AT 2026nwl: KAIT optical observations
- GRB 260601B: CALET Gamma-Ray Burst Monitor detection
- EP260602a: Optical upper limits with Kinder observations
- GRB 260601B / EP260601a: NuSTAR detection of prompt emission
- GRB 260601B/EP260601a: SVOM/VT optical observations
- GRB 260601B/EP260601a: GECAM-B analysis suggests a possible long duration Type I burst
- GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
- EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
- GRB 260601A: Glowbug gamma-ray detection of a short burst
- GRB 260531B: Glowbug gamma-ray detection
- GRB 260516D: VLA radio detection
- GRB 260527A/EP260527a: Glowbug gamma-ray detection
- Fermi GRB 260601A: Global MASTER-Net observations report
- GRB 260531B: GECAM-B observation
- GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
- AT 2026nuz: COLIBRÍ optical observations
- IPN triangulation of GRB 260527A / EP260527a
- EP260527a/GRB 260527A: further FTW optical and NIR observations
- GRB 260527A / EP260527a: VLA radio detection
- EP260527a/GRB 260527A: optical upper limit with Kinder observations
- GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
- GRB 260529A: GOTO tentative optical afterglow candidate
- GRB 260527A/EP260527a: VLT/X-shooter tentative redshift
- GRB 260527A/EP260527a: Insight-HXMT detection
- Fermi GRB 260529A: Global MASTER-Net observations report
- EP260526a: SVOM/VT optical upper limits
- GRB 260527A/EP260527a: Gemini GMOS-S Optical Observations
- EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
- EP260527a / GRB 260527A: NOT optical observations
- GRB 260527A/EP260527a: FTW optical and NIR observations
- EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
- GRB 260527A: CALET Gamma-Ray Burst Monitor detection
- EP260527a/GRB 260527A: EP-FXT follow-up observation
- GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
- GRB 260526A: GECAM-B observation
- Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
- EP260526a: EP-FXT follow-up observation
- EP260527a: SVOM/VT optical observation
- EP260527a: COLIBRÍ optical detection
- EP260526a: LCO optical upper limits
- EP260526a: Einstein Probe detection of a fast X-ray transient
- GRB 260525A: AstroSat CZTI detection
- The EP-WXT trigger 01709266106 is not a real source
- Fermi GRB 260526A: Global MASTER-Net observations report
- Fermi GRB 260525A: Global MASTER-Net observations report
- GRB 260523B: AstroSat CZTI detection
- GRB 260523B: GECAM-B observation
- Fermi GRB 260523A: Global MASTER-Net observations report
- GRB 260522A: Fermi GBM Observation
- GRB 260522B: NuSTAR detection of prompt emission
- EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
- GRB 260522A: GOTO optical upper limit
- Fermi GRB 260522A: Global MASTER-Net observations report
- GRB 260522A: Fermi-LAT detection
- GRB 260519C: SVOM/GRM observation
- GRB 260511A: iTelescope T-75 optical detection
- GRB 260520B: SVOM/GRM observation
- GRB 260411B: TERI Gamma-ray detection
- GRB 260407A: TERI Gamma-ray detection
- GRB 260307A: TERI Gamma-ray detection
- GRB 260225D: TERI Gamma-ray detection
- GRB 251118A: TERI Gamma-ray detection
- GRB 251113A: TERI Gamma-ray detection
- GRB 260428A: TERI Gamma-ray detection
- Konus-Wind detection of GRB 260519C
- GRB 260509A: SVOM/ECLAIRs refined analysis
- GRB 260519C: NuSTAR detection of prompt emission
- Konus-Wind detection of GRB 260518A
- GRB 260516D: SVOM/ECLAIRs refined analysis
- GRB 260515A: SVOM/ECLAIRs refined analysis
- GRB 260421B: radio detection with the VLA
- GRID detection of GRB 260511A
- GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
- GRB 260509A: CrAO ZTSh optical upper limit
- GRB 260516D: EP-FXT follow-up observation
- GRB 260516D: GOTO optical counterpart detection
- GRB 260516D: LCO optical observations
- GRB 260515A: further Liverpool Telescope observations
- GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
- GRB 260516D: GROWTH-India Telescope optical detection
- GRB 260516D: SVOM/VT optical bright candidate
- GRB 260515A: CrAO ZTSh BVRI optical observations
- Fermi GRB 260516C: Global MASTER-Net observations report
- Konus-Wind detection of GRB 260515A
- GRB 260515A: Liverpool Telescope optical detection
- GRB 260515A: LCO optical counterpart detection
- GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 260515A: EP-FXT follow-up observation
- EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
- EP260514a: NOT optical counterpart confirmation
- EP260514a: TRT optical counterpart candidate
- EP260514a: SVOM/VT optical candidate
- Fermi GRB 260516B: Global MASTER-Net observations report
- GRB 260515A: SVOM/VT optical observations
- GRB 260515A: OHP/T193 optical observations
- EP260514a: COLIBRÍ optical upper limits