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').
22242 results found.
- GRB 240306A: Swift/BAT-GUANO detection of a burst
- GRB 240305A: Fermi GBM observation
- Fermi-LAT gamma-ray observations of IceCube-240229A
- GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 231028C: Glowbug gamma-ray confirmation of a prior burst
- GRB 240218A: ALMA detection
- GRB 240303B: VZLUSAT-2 detection
- GRB 240229A: VZLUSAT-2 detection
- Swift Trigger 1218701: Yes, we triggered on Swift J151857.0-572147 again
- Swift Trigger 1218696: Another trigger on Swift J151857.0-572147
- GRB240218A: ATCA observation of the radio counterpart
- Transient EPW20240219aa: Optical observations with LDT
- Swift J151857.0-572147: Swift-BAT refined analysis
- GRB 240303B: Fermi GBM Detection
- GRB 240225B: Swift-XRT afterglow detection
- Swift detection of Swift J151857.0-572147
- Fermi trigger No 731161136: Global MASTER-Net observations report
- GRB 240303C: BALROG localization (Fermi Trigger 731189113 / GRB 240303837)
- GRB 240303B: BALROG localization (Fermi Trigger 731161136 / GRB 240303513)
- GRB 240303A: Swift detection of a burst
- GRB 240225B: Glowbug gamma-ray detection
- IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240225C: Glowbug gamma-ray detection
- GRB 240225A (short): Glowbug gamma-ray detection
- GRB 240229A: DDOTI Upper Limits on the Afterglow
- GRB 240218A: NOEMA upper limit
- GRB 240225B: further SAO RAS optical observations
- GRB 240229A: BALROG localization (Fermi Trigger 730908432 / GRB 240229588)
- GRB 240225B: VLT/X-shooter redshift
- GRB 240225B : MITSuME Akeno optical afterglow candidate detection
- GRB 240225B: 3.6m DOT observation
- GRB 240225B: WINTER near-IR observations and upper limits
- GRB 240225B: SAO RAS optical observations
- GRB 240225B: Mondy afterglow observations
- GRB 240218A: CMO SAI NIR upper limit
- GRB 240225B: Nanshan/HMT optical afterglow detection
- GRB 240225B: Swift-XRT observations
- Transient EPW20240219aa: Kp-band imaging observations with NIRES
- Transient EPW20240219aa: J-band upper limits from WINTER
- Transient EPW20240219aa: REM optical/NIR upper limits
- GRB 240225B: AstroSat CZTI detection
- GRB 240225B: MAXI/GSC detection
- Transient EPW20240219aa: Xinglong-2.16m optical upper limit
- GRB 240225A: Swift/BAT-GUANO detection of a short burst
- Transient EPW20240219aa: GECKO: LOAO Optical Upper Limits
- Transient EPW20240219aa: 7DT Optical Upper Limits
- VLA X-band observation of EPW20240219aa
- Transient EPW20240219aa: Mondy optical observations
- Transient EPW20240219aa: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
- Insight-HXMT/HE Sub-Threshold Detection of Transient EPW20240219aa
- Transient EPW20240219aa: Liverpool Telescope non-detection and limiting magnitude
- GRB 240222A: GECAM detection of a burst
- GRB 240222A: Swift-BAT refined analysis
- GRB 240222A: Swift-XRT refined Analysis
- GRB 240222A: Fermi GBM Observation
- GRB 240222A: Swift/UVOT Upper Limits
- Fermi GBM Sub-Threshold Detection of EPW20240219aa as a likely GRB
- GRB 240222A: REM optical and NIR early-time observations
- GRB 240222A: Swift detection of a burst
- GRB 240218A: MeerLICHT upper limits
- GRB 240216A: Glowbug gamma-ray detection
- GRB 240215B: Fermi GBM Observation
- GRB 240218A: LBT H-band detection
- GRB 240218A: Swift-BAT refined analysis
- GRB 240218A: Swift-XRT refined Analysis
- GRB 240218A: VLT/X-shooter redshift of z = 6.782
- GRB 240218A: Fermi GBM Detection
- GRB 240215A: Fermi GBM Observation
- GRB 240218A: Enhanced Swift-XRT position
- GRB 240218A: REM detection of a NIR afterglow candidate
- GRB 240218A : r-band upper limit from Observatoire de Haute-Provence
- GRB240218A: VLT/X-shooter upper limits
- GRB 240218A: Swift detection of a burst
- GRB 240215B: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 240215A: Swift/BAT-GUANO localization of a burst
- GRB 240213A: Glowbug gamma-ray detection
- GRB 240128A: Further Swift-XRT observations
- GRB 240214A/1H 0451-560: MAXI/GSC detection
- GRB 240213A: BALROG localization (Fermi Trigger / GRB 240213841)
- GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
- GRB 240209A: GOTO optical counterpart candidate
- Konus-Wind detection of GRB 240204A
- IPN triangulation of GRB 240205A (short)
- Fermi-LAT gamma-ray observations of IceCube-240204A
- GRB 240205B: PRIME near infrared detection
- GRB 240205A (short): Glowbug gamma-ray detection
- GRB240204A: Swift/UVOT Upper Limits
- GRB 240205B: Swift-BAT refined analysis
- Konus-Wind detection of GRB 240205B (long / very soft)
- GRB 240205B: VLT/X-shooter redshift
- GRB 240205B: REM detection of the optical/NIR afterglow
- GRB 240205B: Fermi GBM Observation
- GRB 240204A : OHP/T193/T120 optical afterglow fading detection
- GRB 240205B: GECAM detection of a long burst
- GRB 240204A: Swift-BAT refined analysis
- GRB 240205B: Skynet Optical Afterglow Observations
- Fermi trigger No 728749569: Global MASTER-Net observations report
- GRB 240204A: Fermi GBM Observation
- GRB 240204a: Liverpool Telescope optical afterglow detection
- GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit