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.
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
15494 results found.
- LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates
- GRB 240415A: Glowbug gamma-ray detection
- GRB 240414A: Glowbug gamma-ray detection
- LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
- EP 240416a: Xinglong and NOT decaying optical counterpart
- GRB 240411A: Glowbug gamma-ray detection
- EP240416a: Kinder optical counterpart candidate
- EP240416a: EP-WXT detection of a fast X-ray transient
- GRB 240414A: AbAO optical upprer limit
- GRB 240415A: Swift/UVOT Detection
- GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
- GRB 240415A: Earliest optical followup with the Kinder observations
- GRB 240414A: GMG observation
- EP240414a: EP-FXT follow-up observation
- GRB 240415A: Enhanced Swift-XRT position
- GRB 240415B: Swift ToO observations
- GRB 240415A: OHP/T193 optical observations
- GRB 240415A: SAO RAS optical observations
- GRB 240415A: Mondy optical transient detection
- GRB 240414A: Photometric observation from 2.2m CAHA
- GRB 240414A: Swift/UVOT Detection
- LXT 240402A/GRB 240402B: Swift follow-up observations
- GRB 240414A: Mondy optical observations
- GRB 240414A: AKO Optical Upper Limit
- GRB 240415A: Prompt Swift-XRT observations
- EP 240414a: NOT optical counterpart confirmation
- GRB240414A : J-band upper limits from WINTER
- GRB 240414A: Enhanced Swift-XRT position
- GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
- GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
- LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
- EP240413A: GOTO optical upper limits
- GRB 240414A: Skynet Optical Afterglow Observations
- EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
- IPN triangulation of GRB 240410A
- 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
- 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
- GRB 240411B: HiPERCAM/GTC observation
- GRB 240411B: 1.3m DFOT Optical observations
- 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
- EP240408a: EP-WXT detection of a fast X-ray transient
- Swift Trigger 1220736: detection of 4U 1543-62.
- GRB 240408A: Fermi GBM Final Real-time Localization
- Fermi-LAT gamma-ray observations of IceCube-240327B
- Fermi-LAT gamma-ray observations of IceCube-240327A
- GRB 240402C: Glowbug gamma-ray 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
- GRB/FXT 240402B: Kinder optical counterpart candidate
- IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
- X-ray transient LXT 240402A: LEIA detection
- 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
- GRB 240329A: Glowbug gamma-ray detection
- GRB 240331A: AstroSat CZTI detection
- GRB 240329A: AstroSat CZTI detection
- X-ray transient EP240315a: continued ATCA monitoring
- GRB 240328C: Glowbug gamma-ray detection
- X-ray transient EP240315a: Ondrejov D50 optical limit
- Transient EPW20240219aa: REM optical/NIR further observations
- GRB 240320A: Glowbug gamma-ray detection
- GRB 240318A: Fermi GBM Observation
- 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 240317A: 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
- Changes to the Fermi-GBM Triggering Thresholds
- GRB240204A: VIRT optical upper limit
- GRB 240312A: Glowbug gamma-ray 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