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"6805 results found.
- EP261010a: NOT optical upper limits
- EP261006a: Xinglong 2.16m/BFOSC optical follow-up observations
- EP261007b: NOT optical observations, variable source outside the FXT region
- EP261006a: Swift/XRT detection of the fading X-ray counterpart
- GRB 261007A/EP261007a: Optical follow-up observations with Kinder
- EP261006a: Optical follow-up observations with Kinder
- GRB 261007A: Swift-XRT afterglow detection
- GRB 261007A: Fermi GBM observation
- GRB 261005B: Swift-XRT refined Analysis
- GRB 261005B: Fermi GBM Observation
- EP#01709320865: Swift-XRT observations
- Konus-Wind detection of GRB 260919A / EP 260920a
- Fermi-LAT Gamma-ray Observations of IceCube-260930A
- EP260927a: Einstein Probe detection of a fast X-ray transient
- GRB 260925A: Swift-XRT refined Analysis
- EP260924a: EP-FXT follow-up observation
- Konus-Wind detection of GRB 260924A
- GRB 260924A: Optical follow-up observations with Kinder
- GRB 260924A: Swift-XRT refined Analysis
- Konus-Wind detection of GRB 260921A (correction to GCN 45722)
- GRB 260924A: Fermi GRB Observation
- Konus-Wind detection of GRB 260921A (possible merger-origin)
- GRB 260924A: Fermi-LAT detection of a bright burst
- Fermi-LAT Gamma-ray Observations of IceCube-260919A
- Fermi-LAT Gamma-ray Observations of IceCube-260916A
- GRB 260922A: Swift-XRT refined Analysis
- Fermi-LAT Gamma-ray Observations of IceCube-260805A
- GRB 260921A: Fermi GBM Observation
- EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260917a: refined analysis of the EP-FXT observations
- GRB 260915A: Swift-XRT afterglow detection
- GRB 260916B: Fermi GBM Detection
- GRB 260909A: Swift-XRT observations
- GRB 260914A: EP-FXT follow-up observation
- GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
- GRB 260903A: Swift-XRT observations
- GRB 260903A: SAO RAS optical upper limit
- EP260903a: EP-FXT follow-up observation
- GRB 260903A: SAO RAS optical observations
- NuSTAR Transient 260828: SOAR Optical Upper Limits
- EP260901a: EP-FXT follow-up observation
- EP260830a: EP-FXT follow-up observation
- NuSTAR Transient 260828: LCO Optical Upper Limits
- Fermi-LAT Gamma-ray Observations of IceCube-260827A
- Fermi-LAT Gamma-ray Observations of IceCube-260825A
- GRB 260829A: Fermi GBM Detection
- GRB 260818B: Further EP-FXT observation
- GRB 260808B: SAO RAS observations of the optical rebrightening
- GRB 260807A: EP-FXT follow-up observations
- GRB 260822A: EP/FXT follow-up observations
- GRB 260822A: GROWTH-India Telescope Upper Limits
- Fermi-LAT Gamma-ray Observations of IceCube-260821A
- Fermi-LAT Gamma-ray Observations of IceCube-260807A
- GRB 260818B: EP-FXT follow-up observation
- GRB260818A: EP-FXT follow-up observation
- EP260806a: SAO RAS multicolor optical observations
- EP260812b: Optical upper limit with Kinder
- EP260812a: NOT and Liverpool Telescope upper limits:
- GRB 260809A: SAO RAS optical observations
- GRB 260808B: SAO RAS optical observations
- GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
- GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
- AT 2026wki: EP/FXT follow-up observations
- GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
- GRB 260727A: EP-FXT further follow-up observations and candidate afterglow
- Fermi-LAT Gamma-ray Observations of IceCube-260722A
- EP260727a: SAO RAS optical observations
- EP260728a: EP-FXT follow-up observation
- GRB 260726A: EP-FXT follow-up observations
- GRB 260726A: Fermi GBM Observation
- Konus-Wind detection of GRB 260727A
- GRB 260727A: EP/FXT follow-up observations
- EP260723a: further EP-FXT follow-up observation
- EP260725a: EP-WXT detection of an X-ray transient
- EP260723a: EP-FXT follow-up observation
- GRB 260718A: EP-FXT follow-up observation
- GRB 260718A: Fermi GBM Observation
- GRB 260310A / AT2026fgk: Late-time Chandra Detection
- GRB 260618B: EP-FXT follow-up observation upper limit
- GRB 260714B: Fermi-LAT detection
- GRB 260714B: Fermi GBM Detection
- GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
- EP260711a: EP-FXT follow-up observation
- Fermi-LAT Gamma-ray Observations of IceCube-260712A
- Fermi-LAT Gamma-ray Observations of IceCube-260708A
- Fermi-LAT Gamma-ray Observations of IceCube-260704A
- GRB 260710A: Fermi GBM Detection
- GRB 260708A: Fermi-GBM observation
- GRB 260708A: Fermi-LAT detection
- GRB 260706A: Further EP-FXT follow-up observation
- GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
- GRB 260706A: EP-FXT follow-up observation
- GRB 260706A: Fermi GBM Observation
- GRB 260704A: EP-FXT follow-up observation
- EP260703a: EP-FXT follow-up observation
- EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
- Fermi-LAT Gamma-ray Observations of IceCube-260622A
- EP260628a: EP-FXT follow-up observation
- EP260626a: EP-FXT follow-up observation
- Konus-Wind detection of GRB 260623B / EP260623a