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').
17298 results found.
- EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
- EP240414a: EP-WXT detection of a fast X-ray transient
- IPN triangulation of GRB 240411A
- Fermi-LAT gamma-ray observations of IceCube-240412A
- GRB 240414A : MITSuME Akeno optical upper limits
- EP240413a: EP-WXT detection of a fast X-ray transient
- GRB 240414A : OHP/T193 optical counterpart detection
- GRB 240414A: Swift detection of a burst
- GRB 240411B: CrAO/ZTSh optical observations
- GRB 240411B: Kinder observations with Lulin observatory
- LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate
- GRB 240411B: HiPERCAM/GTC observation
- GRB 240411B: 1.3m DFOT Optical observations
- GRB 240411A: GRBAlpha detection
- GRB 240411B: OHP/T193 optical observations
- GRB 240405A: Glowbug gamma-ray detection
- GRB 240411B: Enhanced Swift-XRT position
- GRB 240411B: LCO optical afterglow detection
- GRB 240411B: Swift detection of a burst
- GRB 240408B: GRBAlpha detection
- X-ray transient EP240315a: second epoch e-MERLIN radio observations
- GRB 240405A: GRBAlpha detection
- EP240408a: EP-WXT detection of a fast X-ray transient
- Swift Trigger 1220736: detection of 4U 1543-62.
- IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
- Fermi-LAT gamma-ray observations of IceCube-240327B
- Fermi-LAT gamma-ray observations of IceCube-240327A
- LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
- GRB 240405B: Fermi GBM Final Real-time Localization
- GRB 240402C: Glowbug gamma-ray detection
- GRB 240405A: Fermi GBM Final Real-time Localization
- GRB 240402C: GRBAlpha detection
- GRB 240331A: GRBAlpha detection
- GRB 240403B: Glowbug gamma-ray detection
- GRB 240403A: Glowbug gamma-ray detection
- LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
- X-ray transient LXT 240402A: WFST optical upper limits
- Konus-Wind detection of LXT 240402A/GRB 240402B
- GRB/FXT 240402B: Kinder optical counterpart candidate
- IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
- GRB 240402B: GWAC-F50A optical upper limit
- Fermi trigger No 733808041: Global MASTER-Net observations report
- X-ray transient EP240331a: Kinder optical upper limits
- Transient EP240315a: J-band observations of AT2024eju with WIRC
- X-ray transient EP20240331a: MeerLICHT optical upper limits
- Integral GRB240401.69: Global MASTER-Net observations report
- GRB 240329A: Glowbug gamma-ray detection
- GRB 240329A: AstroSat CZTI detection
- GRB 240329A: GRBAlpha detection
- X-ray transient EP240315a: continued ATCA monitoring
- GRB 240328C: Glowbug gamma-ray detection
- X-ray transient EP240315a: e-MERLIN radio observations
- X-ray transient EP240315a: Ondrejov D50 optical limit
- Transient EPW20240219aa: REM optical/NIR further observations
- GRB 240320A: Glowbug gamma-ray detection
- Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
- X-ray transient EP240315a: ATCA detection of radio counterpart
- IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a)
- X-ray transient EP240315a: MeerKAT radio detection
- GRB 240318A: Glowbug gamma-ray detection
- GRB 240317C: Glowbug gamma-ray detection
- GRB 240318B: Glowbug gamma-ray detection
- X-ray transient EP240315a: PRIME near infrared detection
- X-ray transient EP240315a: 3.6 m TNG NIR detection
- X-ray transient EP240315a/AT2024eju: TShAO (Zeiss-1000) observatory optical upper limit
- GRB 240315B: AstroSat CZTI detection
- X-ray transient EP240315a: Kitab observatory optical upper limitns
- X-ray transient EP240315a: Montarrenti Observatory optical upper limit
- X-ray transient EP240315a: orphan FXT?
- X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
- X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
- X-ray transient EP240315a: Nanshan/HMT optical upper limit
- Einstein Probe detected of a fast X-ray transient EP240315a
- GRB240204A: VIRT optical upper limit
- GRB 240312A: Glowbug gamma-ray detection
- GRB 240312A: GECAM detection of a long burst
- GRB 240303C: VZLUSAT-2 detection
- Fermi-LAT gamma-ray observations of IceCube-240307A
- GRB 240310B: Glowbug gamma-ray detection
- GRB 231215A: further radio observations with the VLA
- GRB 240229A: Glowbug gamma-ray detection
- GRB 240227A (short): Glowbug gamma-ray detection
- GRB 240229A: GRBAlpha detection
- Fermi-LAT gamma-ray observations of IceCube-240229A
- GRB 240305C: Fermi GBM Final Real-time Localization
- GRB 240305A: Swift/BAT-GUANO arcminute localization of a burst
- GRB 231028C: Glowbug gamma-ray confirmation of a prior burst
- GRB 240303B: VZLUSAT-2 detection
- GRB 240229A: VZLUSAT-2 detection
- GRB 240305A: Fermi GBM Final Real-time Localization
- Swift Trigger 1218701: Yes, we triggered on Swift J151857.0-572147 again
- GRB240218A: ATCA observation of the radio counterpart
- Transient EPW20240219aa: Optical observations with LDT
- Konus-Wind detection of GRB 240303B
- GRB 240225B: Swift-XRT afterglow detection
- Swift detection of Swift J151857.0-572147
- GRB 240303A: Swift detection of a burst
- GRB 240225B: Glowbug gamma-ray detection
- GRB 240225C: Glowbug gamma-ray detection
- GRB 240225A (short): Glowbug gamma-ray detection