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"32571 results found.
- EP260602a: GTC and Liverpool Telescope optical observations
- Konus-Wind detection of GRB 260601B/EP260601a
- GRB 260603A: EP-FXT follow-up observation
- EP260601a/GRB 260601B: EP-FXT follow-up observation
- GRB 260601B / EP260601a: Mondy optical upper limit
- EP260602b: EP-FXT follow-up observation
- GRB 260601B/EP260601a: Glowbug gamma-ray detection
- GRB 260603A: Kilonova-Catcher optical upper limit
- GRB 260603A: SVOM/VT optical observations
- EP260602a: NOT NIR J-band observations
- GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
- EP260602d: Einstein Probe detection of a fast X-ray transient
- EP260602a: SVOM/VT optical magnitudes correction
- GRB 260601A: SVOM/GRM observation of a short burst
- EP260602c: Einstein Probe detection of a fast X-ray transient
- GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
- EP260602a: COLIBRÍ optical observations
- GRB260601B/EP260601a: NOT near-infrared observations
- EP260602b: Einstein Probe detection of a fast X-ray transient
- GRB 260601B/EP260601a: Insight-HXMT detection
- Fermi GRB 260602B: Global MASTER-Net observations report
- Fermi GRB 260602B: Global MASTER-Net observations report
- EP260602a: SVOM/VT optical candidate
- 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