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"14824 results found.
- GRB 260530A: Fermi GBM Final Real-time Localization
- GRB 260527A / EP260527a: VLA radio detection
- GRB 260527A/EP260527a: Insight-HXMT detection
- GRB 260529A: Fermi GBM Final Real-time Localization
- EP260526a: SVOM/VT optical upper limits
- EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
- 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
- Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
- EP260526a: EP-FXT follow-up observation
- EP260527a: COLIBRÍ optical detection
- EP260527a: Einstein Probe detection of a fast X-ray transient
- GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
- EP260526a: LCO optical upper limits
- EP260526a: Einstein Probe detection of a fast X-ray transient
- GRB 260525A: AstroSat CZTI detection
- GRB 260526A: Fermi GBM Final Real-time Localization
- EP01709266106 (EP260526a?): Liverpool Telescope upper limits
- GRB 260525A: Fermi GBM Final Real-time Localization
- GRB 260523B: AstroSat CZTI detection
- GRB 260523B: Fermi GBM Final Real-time Localization
- GRB 260523A: Fermi GBM Final Real-time Localization
- GRB 260522B: NuSTAR detection of prompt emission
- GRB 260522B: Fermi GBM Final Real-time Localization
- EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
- GRB 260522A: Fermi-LAT detection
- GRB 260522A: Fermi GBM Final Real-time Localization
- GRB 260511A: iTelescope T-75 optical detection
- 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 260520B: Fermi GBM Final Localization
- GRB 260520A: Fermi GBM Final Localization
- GRB 260519D: Fermi GBM Final Localization Correction
- GRB 260519C: NuSTAR detection of prompt emission
- Konus-Wind detection of GRB 260518A
- GRB 260519B: Fermi GBM Final Localization
- GRB 260519A: Fermi GBM Final Localization
- GRB 260518A: AstroSat CZTI detection of a long burst
- GRB 260421B: radio detection with the VLA
- GRID detection of GRB 260511A
- GRB 260516D: GOTO optical counterpart detection
- GRB 260515A: further Liverpool Telescope observations
- GRB 260516D: GROWTH-India Telescope optical detection
- GRB 260516D: FRAM-ORM optical limit
- GRB 260515A: CrAO ZTSh BVRI optical observations
- GRB 260516D: SVOM possible detection of a burst
- GRB 260516C: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 260515A
- GRB 260515A: Liverpool Telescope optical detection
- GRB 260515A: LCO optical counterpart detection
- 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
- GRB 260516B: Fermi GBM Final Real-time Localization
- GRB 260515A: SVOM/VT optical observations
- GRB 260515A: OHP/T193 optical observations
- GRB 260516A: Fermi GBM Final Real-time Localization
- GRID detection of GRB 260507A
- GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
- GRB 260515A: LCO optical observations
- GRB 260515A: NOT optical observations.
- SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
- GRB 260515A: SVOM/VT optical candidate from VHF data
- GRB 260515A: JinShan optical counterpart candidate
- GRB 260515A: SVOM detection of a burst
- GRB 260510C: Glowbug gamma-ray detection
- Konus-Wind detection of GRB 260512A
- GRB 260510C: CALET Gamma-Ray Burst Monitor detection
- EP260514a: Einstein Probe detection of a fast X-ray transient
- EP260512a: LCO optical upper limits
- IPN triangulation of GRB 260512A
- GRB 260512A: AstroSat CZTI detection
- EP260512a: EP-FXT follow-up observation
- EP260507a: Xinglong Schmidt optical counterpart detection
- GRB 260514A: Fermi GBM Final Real-time Localization
- GRB 260513A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 260511B
- EP260512a: Einstein Probe detection of an X-ray transient
- GRB 260512A: NuSTAR detection of prompt emission
- GRB 260512A: Fermi GBM Final Real-time Localization
- GRB 260511A: Glowbug gamma-ray detection
- Konus-Wind detection of GRB 260511A
- MASS-Cube (GRID 2.0) detection of GRB 260511A
- MASS-Cube (GRID 2.0) detection of GRB 260507A
- GRB 260510D: Glowbug gamma-ray detection of a likely short burst
- GRB 260511B: FRAM-ORM optical detection
- GRB 260511B: LCO optical counterpart detection
- GRB 260511B: GOTO optical counterpart detection
- GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
- GRB 260511A: REM near-infrared detection
- GRB 260511B: AstroSat CZTI detection
- GRB 260506B: Glowbug gamma-ray detection