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"
440 results found.
- GRB 250512B / EP250512a: SVOM/GRM analysis
- EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
- GRB 250512B/EP250512a:SVOM/VT bright optical counterpart
- GRB 250512B: SVOM detection of a burst
- EP250512a: Einstein Probe detection of an X-ray transient
- EP250511a: Einstein Probe follow-up obsevation and refined analysis
- EP250511a: SVOM/VT optical candidate comfirmation
- EP250511a: Einstein Probe detection of an X-ray transient
- GRB 250510A: follow-up observation with EP-FXT
- EP250508a: follow-up observation with EP-FXT
- EP250508a: refined analysis of the EP-WXT and EP-FXT observations
- EP250508a: Einstein Probe detection of an X-ray transient
- GRB 250507A: follow-up observation with EP-FXT
- EP#01709175213/IGR J19566+0326: Swift-XRT detection
- EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
- SVOM/sb25050601: EP-FXT observations
- SVOM/sb25043004: EP-FXT observations
- EP250430a/GRB 250430A: Einstein Probe WXT detection of the X-ray prompt emission
- EP 250427A: Optical counterpart detection by LCO.
- EP250428b: refined analysis of the EP-FXT follow-up observation
- EP250428b: SVOM/VT upper limit
- GRB 250427A: Swift/UVOT Detection
- EP250428b: Einstein Probe detection of a fast X-ray transient
- EP250427a: EP-FXT follow-up observations
- EP250427a: LT optical counterpart detection
- GRB 250427A: Swift-XRT refined Analysis
- EP250427a: Einstein Probe detection of a fast X-ray transient
- EP250416a / GRB 250416C: Gemini GMOS-S likely host galaxy redshift z = 0.963
- EP250421a: Einstein Probe detection of an X-ray transient
- EP250416a: refined EP-WXT and EP-FXT analysis
- EP250416a: Gemini South-GMOS optical counterpart
- EP250416a: GSP optical upper limit
- EP250416a: Einstein Probe detection of an X-ray transient
- EP250304a: ATCA radio observations
- EP250404a: Nanshan 0.43m Telescope optical observatios
- EP250407a: Swift-XRT observations
- GRB 250407A: EP-WXT afterglow detection
- EP250407a: EP-WXT detection of a fast X-ray transient
- EP250404a / GRB 250404A: Montarrenti Observatory optical observations
- GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
- EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
- EP250404a: refined analysis of the EP-WXT and EP-FXT observations
- GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
- EP250402a: Optical upper limit with PD 1.3m observations
- EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
- EP250404a: Seimei/TriCCS optical counterpart detection
- EP250404a: LAST detection of optical counterpart
- EP250404a: BOOTES-4/JGT optical afterglow detection
- EP250404a: Einstein Probe detection of an X-ray transient
- GRB 250402A: EP-FXT afterglow detection
- EP250402a: EP-FXT follow-up observations
- The EP-WXT trigger 01709133862 is a flaring star
- EP250402a: Einstein Probe detection of a fast X-ray transient
- FRB 20250316A: FTW optical observations
- FRB 20250316A: The sub-arcsecond localization of FRB 20250316A using CHIME/FRB Outriggers coincides with reported X-ray counterparts
- The EP-WXT trigger 01709133021 (designated as EP250324a) is not a real source
- EP-WXT trigger 01709133021: Optical upper limit through Kinder observations
- FRB 250316A: COLIBRÍ/DDRAGO Optical follow up of the X ray source EP J120944.2+585060
- FRB 20250316A: Kinder optical upper limits of the Einstein Probe candidate X-ray source EP J120944.2+585060
- FRB 20250316A: detection of a candidate associated X-ray source EP J120944.2+585060 by Einstein Probe
- EP250321a: refined analysis of the EP-WXT and EP-FXT observations
- EP250321a: KAIT optical observations
- EP250321a: WFST optical observations
- EP 250321A: Optical counterpart detection by LCO.
- EP250321a: Swift-XRT detection of an X-ray source
- EP250321a: VLT/X-shooter redshift z = 4.368
- EP250321a: BOOTES-5/JGT optical afterglow detection
- EP250321a: Einstein Probe detection of an X-ray transient
- GRB 250309B: Proof-of-concept for Joint ZTF+EP Experiment
- The EP-WXT trigger 01709132801 is likely a flaring star
- GRB 250314A: EP-FXT afterglow detection
- EP250315a: refined analysis of the EP-WXT and EP-FXT observations
- EP250315a: Einstein Probe detection of an X-ray transient
- EP250311a/GRB 250311A: Correction to EP-WXT detection time
- The EP-WXT trigger 01709132551 is not a real source
- EP250311a/GRB 250311A: EP-FXT follow-up observation
- EP250311a/GRB 250311A: EP-WXT detection
- The EP-WXT trigger 01709132425 is not a real source
- EP250308a: GSP optical upper limit
- EP250308a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709132387 is likely a flaring star
- The EP-WXT trigger 01709132323 is likely a flaring star
- EP 250304A: Optical counterpart detection by LCO
- EP250304a: refined analysis of the EP-WXT and EP-FXT observations
- EP250304a: Swift/UVOT detection of an optical counterpart with a rising light curve
- EP250304a: Swift-XRT detection of a fading X-ray source
- EP250304a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709132212 is not a real source
- EP250302a: Swift/UVOT detection
- EP250302a: NUTTelA-TAO Early Measurments
- EP250302a: Einstein Probe detection of an X-ray transient
- EP250302a: SVOM/C-GFT optical observations
- EP250302a: Montarrenti Observatory optical detection
- EP250302a: Nanshan/HMT optical counterpart detection
- The EP-WXT trigger 01709132140 is likely a flaring star
- LIGO/Virgo/KAGRA S250206dm: early X-ray upper limits from Einstein Probe WXT and preliminary results of FXT observations
- EP250227a: Einstein Probe detected of a fast X-ray transient
- EP250228a: updates on the EP observations
- EP250225a: EP-FXT follow-up observation
- EP250228a: Swift/XRT localisation