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').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"16161 results found.
- GRB 240414A : MITSuME Akeno optical upper limits
- GRB 240414A : OHP/T193 redshift determination
- GRB 240414A : OHP/T193 optical counterpart detection
- EP240408a: GSP optical upper limit
- GRB 240411B: CrAO/ZTSh optical observations
- GRB 240411B: Kinder observations with Lulin observatory
- GRB 240411B: 1.3m DFOT Optical observations
- GRB 240411B: OHP/T193 optical observations
- GRB 240411B: LCO optical afterglow detection
- EP240408A: MASTER optical observations
- EP240408a: GROND detection of a candidate counterpart
- EP240408a: BOOTES-6/DPRT optical upper limit
- X-ray transient EP240315a: second epoch e-MERLIN radio observations
- IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
- 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
- GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
- X-ray transient LXT240402A: AST3-3 optical upper limits
- LXT 240402A: MASTER optical observations with AGN in error-box
- GRB 240402B: GWAC-F50A optical upper limit
- X-ray transient EP240331a: Kinder optical upper limits
- X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
- EP240331A: MASTER optical observations
- Transient EP240315a: J-band observations of AT2024eju with WIRC
- X-ray transient EP20240331a: MeerLICHT optical upper limits
- X-ray transient EP240315a: continued ATCA monitoring
- X-ray transient EP240315a: e-MERLIN radio observations
- X-ray transient EP240315a: Ondrejov D50 optical limit
- Transient EPW20240219aa: REM optical/NIR further observations
- X-ray transient EP240315a: ATCA detection of radio counterpart
- X-ray transient EP240315a: GTC/HiPERCAM photometry
- X-ray transient EP240315a: MeerKAT radio detection
- X-ray transient EP240315a: GTC/OSIRIS spectroscopic redshift confirmation
- 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
- X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
- 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: GROND J-band detection
- X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
- X-ray transient EP240315a: Nanshan/HMT optical upper limit
- AT2024eju: followup observations with Liverpool Telescope suggest a fading transient
- X-ray transient EP240315a: ATLAS detection of a possible optical counterpart AT2024eju
- Einstein Probe detected of a fast X-ray transient EP240315a
- GRB240204A: VIRT optical upper limit
- Transient EPW20240219aa: Optical observations with LDT
- GRB 240225B: Swift-XRT afterglow detection
- GRB 240225B: further SAO RAS optical observations
- GRB 240225B: VLT/X-shooter redshift
- GRB 240225B : MITSuME Akeno optical afterglow candidate detection
- GRB 240225B: 3.6m DOT observation
- GRB 240225B: SAO RAS optical observations
- GRB 240225B: Mondy afterglow observations
- GRB 240225B: Liverpool Telescope afterglow observations
- Swift J1727.8-1613 (GRB 230824A): Madrona Peak Observatory - optical follow-up
- GRB 240225B: Liverpool Telescope optical afterglow observations
- GRB 240225B: NOT optical observations
- GRB 240225B: Nanshan/HMT optical afterglow detection
- GRB 240225B: Swift-XRT observations
- GRB 240225B: GOTO detection of a candidate optical afterglow
- Transient EPW20240219aa: REM optical/NIR upper limits
- Transient EPW20240219aa: Xinglong-2.16m optical upper limit
- Transient EPW20240219aa: GECKO: LOAO Optical Upper Limits
- Transient EPW20240219aa: 7DT Optical Upper Limits
- Transient EPW20240219aa: Mondy optical observations
- Transient EPW20240219aa: Liverpool Telescope non-detection and limiting magnitude
- GRB 240222A: Swift/UVOT Upper Limits
- GRB 240222A: REM optical and NIR early-time observations
- GRB 240218A: MeerLICHT upper limits
- IPN triangulation of GRB 240209A
- GRB 240218A: REM detection of a NIR afterglow candidate
- GRB 240209A: Classification of AT2024cew/GOTO24pw as Type Ia-pec supernova
- GRB 240209A: Fermi GBM observation
- GRB240209A: OHP/T193 detection of the GOTO afterglow candidate AT2024cew / GOTO24pw
- GRB 240209A: Wendelstein Optical Observations
- GRB 240209A: NOEMA non-detection of AT2024cew / GOTO24pw counterpart candidate
- GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
- GRB 240209A: GOTO optical counterpart candidate
- GRB 240205B: PRIME near infrared detection
- GRB240204A: Swift/UVOT Upper Limits
- GRB 240205B: VLT/X-shooter redshift
- GRB 240205B: BOOTES-6 optical afterglow follow-up
- GRB 240205B: REM detection of the optical/NIR afterglow
- GRB 240204A: Mondy optical afterglow observations
- GRB 240204A : OHP/T193/T120 optical afterglow fading detection
- GRB 240205B: Skynet Optical Afterglow Observations
- GRB 240205B: BOOTES-7 optical afterglow follow-up
- GRB 240204a: Liverpool Telescope optical afterglow detection
- GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
- GRB 240204A: Montarrenti Observatory optical observations
- GRB 240204A: Mondy optical afterglow candidate
- GRB240122A: PRIME near infrared detection
- GRB 240123A: further SAO RAS optical observations
- GRB 240123A: Mondy continued optical observations and the PL decay index
- GRB 240123A: SAO RAS optical observations