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').
22282 results found.
- 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
- IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
- GRB 240204A: Montarrenti Observatory optical observations
- GRB 240204A: Enhanced Swift-XRT position
- GRB 240204A: Mondy optical afterglow candidate
- GRB 240204A: Swift detection of a burst
- Konus-Wind detection of GRB 240123C
- IPN triangulation of GRB 240124B
- GRB 240129A: Fermi GBM Observation
- GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 240128A: Glowbug gamma-ray detection
- GRB 240128A: Swift-XRT observations
- GRB 240125A: GRBAlpha detection
- IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240125A: AstroSat CZTI detection of a short burst
- GRB 240124B: AstroSat CZTI detection
- GRB 240123C: AstroSat CZTI detection
- GRB240122A: PRIME near infrared detection
- GRB 240123B: Fermi GBM Observation
- GRB 240123A: Glowbug gamma-ray detection
- GRB 240125A (short): Glowbug gamma-ray detection
- GRB 240123B: Swift/BAT-GUANO detection of a long burst
- IPN triangulation of GRB 240123C (short)
- Fermi-LAT gamma-ray observations of IceCube-240123A
- GRB 240123A: further SAO RAS optical observations
- GRB 240123A: Swift-BAT refined analysis
- IceCube Alert 240123.48: Global MASTER-Net observations report
- GRB 240123A: SAO RAS optical observations
- GRB 240123A : MITSuME Akeno optical afterglow candidate detection
- GRB 240123A: Enhanced Swift-XRT position
- GRB 240124A?: BALROG localization (Fermi Trigger 727752941 / GRB 240124066)
- GRB 240122A: Swift/UVOT Upper Limits
- GRB 240123A: Swift-XRT refined Analysis
- Fermi GBM Sub-Threshold Detection of GRB 240123A
- GRB 240118A: Swift/UVOT Upper Limits
- GRB 240122B: Glowbug gamma-ray detection
- GRB 240123A: Mondy optical afterglow observations
- GRB 240123A: Swift detection of a burst with a possible optical counterpart
- GRB 240122A: Swift-XRT afterglow detection
- GRB 240122A: GOTO optical counterpart candidate
- IPN triangulation of GRB 240119A (short)
- GRB 240119A: GECAM detection of a short burst
- GRB 240118C: GECAM-B detection of a long burst
- GRB 240119A: AstroSat CZTI detection of a short burst
- GRB 240118A: Mondy optical observations
- GRB 240118A: Swift-XRT afterglow detection
- GRB 240118C: Fermi GBM Observation
- IceCube-240105A: Detection of NIR flare of PKS 0446+11 with WINTER
- GRB 240118C: Swift/BAT-GUANO detection of a burst
- GRB 240118D: AstroSat CZTI detection
- GRB 240118A: AbAO optical upper limit
- GRB 240118A: NuSTAR Offline Analysis of the GRB
- GRB 240117A: Glowbug gamma-ray detection
- GRB 240118A: Swift/BAT-GUANO detection of a burst outside the coded FOV