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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
5468 results found.
- Fermi-LAT gamma-ray observations of IceCube-240204A
- GRB240204A: Swift/UVOT Upper Limits
- Konus-Wind detection of GRB 240205B (long / very soft)
- GRB 240205B: Fermi GBM Observation
- GRB 240204A: Fermi GBM Observation
- GRB 240129A: Fermi GBM Observation
- GRB 240128A: Swift-XRT observations
- GRB 240123B: Fermi GBM Observation
- Fermi-LAT gamma-ray observations of IceCube-240123A
- GRB 240123A: further SAO RAS optical observations
- GRB 240123A: SAO RAS optical observations
- GRB 240122A: Swift/UVOT Upper Limits
- GRB 240123A: Swift-XRT refined Analysis
- GRB 240122A: Swift-XRT afterglow detection
- GRB 240118A: Swift-XRT afterglow detection
- GRB 240118C: Fermi GBM Observation
- GRB 240115A: Fermi GBM Observation
- GRB 240118A: Fermi GBM Observation
- GRB 240118A: Fermi-LAT detection
- GRB 240115B: Fermi GBM Detection
- GRB 240112C: Fermi GBM Detection
- GRB 240112C: Swift-XRT refined Analysis
- GRB 240109A: Fermi GBM Observation
- Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
- GRB GRB240101C: Fermi GBM observation
- GRB 240101A: 1.3m DFOT optical observations
- GRB 240102A: 1.3m DFOT optical upper limit
- GRB 240101B: 1.3m DFOT optical upper limit
- GRB 231220A: Swift-UVOT upper limit
- GRB 240101B: Swift-XRT refined Analysis
- GRB 240102A: Swift-XRT refined Analysis
- GRB 240101A: Swift-XRT refined Analysis
- GRB231230A: Fermi GBM Observation
- GRB 231230A: Swift-XRT refined Analysis
- GRB 231210B: BOOTES-7 optical upper limit
- GRB 231222B: Swift-XRT afterglow detection
- GRB 231222B: Fermi GBM Detection
- GRB 231222B: Fermi-LAT detection
- GRB 231220A: Swift-XRT follow-up observations
- GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
- GRB 231214B: Fermi GBM observation
- GRB 231216A: Swift-XRT refined Analysis
- GRB 231216A: GIT optical upper limit
- Konus-Wind detection of GRB 231215A
- GRB 231215A: Fermi GBM observation
- GRB 231215A: Swift-XRT refined Analysis
- GRB 231214A: Fermi GBM observation
- Konus-Wind detection of GRB 231210B
- GRB 231214A: Swift-XRT refined Analysis
- GRB 231214A: Fermi-LAT detection
- Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
- GRB 231210B: Swift-XRT refined Analysis
- GRB 231205B: 1.3m DFOT Optical upper limit
- GRB 231205B: Swift-XRT refined Analysis
- Fermi-LAT gamma-ray observations of IceCube-231202A
- Fermi-LAT daily aperture light curve of T CrB now available
- GRB 231203A: Fermi GBM Observation
- GRB 231129C: Swift-XRT afterglow detection
- GRB 231129B: Swift-XRT observations
- GRB 231129C: Fermi-LAT detection
- GRB 231129C: Swift-XRT observations
- GRB 231129C: Fermi GBM Observation of a very bright GRB
- GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
- GRB 231129A: Swift-XRT refined Analysis
- Fermi-LAT gamma-ray observations of IceCube-231125A
- GRB 231123C: Fermi GBM Observation
- GRB 231123B: Fermi GBM Observation
- GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
- GRB 231115A: XMM-Newton observation
- GRB 231117A: Chandra afterglow detection
- GRB 231117A: GTC Near-Infrared Observations
- GRB 231118B: Fermi GBM observation
- GRB 231118A: Fermi GBM observation
- GRB 231117A: Swift-XRT refined Analysis
- GRB 231118A: Swift-XRT refined Analysis
- GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
- GRB 231117A: GIT optical follow-up
- GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
- MAGIC observation of GRB 231115A, a possible magnetar giant flare
- GRB 231115A: NuSTAR Follow-Up Observations
- GRB 231115A: Swift-XRT and Swift-UVOT observations
- GRB 231115A: archival Chandra X-ray observations
- GRB 231115A: Kinder observations with Lulin observatory
- GRB 231115A: Fermi Observations of a probable Magnetar Giant Flare from M82
- LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
- GECAM-B observation of a short burst from SGR J1555-5402
- LIGO/Virgo S231113bw: upper limits from AGILE/MCAL
- GRB 231110A: Swift-UVOT Upper Limits
- GRB 231111A: Swift-XRT refined Analysis
- GRB 231110A: SAO RAS optical observations
- GRB 231110A: Swift-XRT afterglow detection
- GRB231111A: GIT confirmation of the optical afterglow
- Fermi-LAT gamma-ray observations of IceCube-231103A
- GRB 231104A: Fermi GBM Observation
- GRB 231104A: Swift-XRT refined Analysis
- GRB 231104A: Fermi-LAT detection
- Fermi-LAT gamma-ray observations of IceCube-231027A
- GRB 231030B: Fermi GBM Detection
- GRB 231028A: Fermi GBM Detection
- GRB 231025A: Fermi GBM Observation