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.
- 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
- GRB 240118C: BALROG localization (Fermi Trigger 727291408 / GRB 240118725)
- GRB 240118A: Fermi GBM Observation
- GRID detection of GRB 231230A
- GRB 240115A: Swift/BAT-GUANO detection of a short burst
- Swift Triggers 1209369 and 1209370 are not astrophysical events
- GRB 240115B: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S240109a: Upper limits from Swift/BAT-GUANO
- GRB 240115B: Fermi GBM Detection
- GRB 240112D: Glowbug gamma-ray detection
- GRB 240112C: Glowbug gamma-ray detection
- GRB 240112C: VZLUSAT-2 detection
- GRB 240114A: MAXI/GSC detection
- GRB 240112C: Swift/UVOT Detection
- GRB 240112C: Fermi GBM Detection
- Fermi trigger No 726773850: Global MASTER-Net observations report
- GRB 240112C: Swift-XRT refined Analysis
- GRB 240112C: SAO RAS optical observations
- GRB 240109A: Swift-BAT refined analysis
- GRB 240112C: Swift detection of a burst with an optical counterpart
- GRB 240112A: GECAM detection of a burst
- 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 240108A: Glowbug gamma-ray detection
- GRB 240106B: Glowbug gamma-ray detection
- GRB 240106A: Glowbug gamma-ray detection
- IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S240109a: Updated Sky localization
- GRB 231215A: radio detection with the VLA
- GRB 230818A: further radio observations with the VLA
- GRB 230812B: further radio observations with the VLA
- Swift GRB240109.17: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240109a: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240104bl: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240107b: Updated Sky localization and Source Classification
- GRB 240107A: MAXI/GSC detection
- LIGO/Virgo/KAGRA S240107b: Identification of a GW compact binary merger candidate
- IPN triangulation of GRB 240101C (short)
- GRB 240101A: 1.3m DFOT optical observations
- GRB 240102A: 1.3m DFOT optical upper limit
- GRB 240101B: 1.3m DFOT optical upper limit
- GRB 240101C: Swift/BAT-GUANO detection of a short burst
- LIGO/Virgo/KAGRA S240104bl: Updated Sky localization
- LIGO/Virgo/KAGRA S240104bl: Identification of a GW compact binary merger candidate
- GRB 240102A: Swift-BAT refined analysis
- GRB 240102A: Swift/UVOT Upper Limits
- GRB 231230A: Swift-BAT refined analysis