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"1056 results found.
- The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
- GRB 260818B: SVOM/VT optical upper limit and continuous observations
- GRB 260822A: SVOM/VT optical upper limits
- GRB 260822A: PRIME near-infrared upper limits from multiple epochs
- GRB 260822A: EP/FXT follow-up observations
- GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
- EP260822a: EP-FXT non-detection and upper limit
- EP260822a: Einstein Probe detection of a fast X-ray transient
- The EP-WXT trigger 01709287395 is likely a flaring star
- The EP-WXT trigger 01709286204 is likely a flaring star
- EP detected a brightening of LMXB 1ES 1735-26.9
- GRB 260818B: EP-FXT follow-up observation
- GRB260818A: EP-FXT follow-up observation
- EP260812a: AbAO optical upper limit
- The EP-WXT trigger 01709281429 is likely a flaring star
- EP260812a: AZT-22 optical upper limit
- EP260806a: WFST optical observations
- The EP-WXT trigger 01709280562 is likely a flaring star
- EP260812b: Optical upper limit with Kinder
- The EP-WXT trigger 01709279838 is likely a flaring star
- EP260812a: NOT and Liverpool Telescope upper limits:
- EP260812b: Liverpool Telescope observations
- EP260812b: GOTO detection of the optical counterpart
- EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
- EP260812b: Einstein Probe detection of an X-ray transient
- EP260812a: Einstein Probe detection of an X-ray transient
- GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
- The EP-WXT trigger 01709278015 is likely a flaring star
- EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
- GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
- EP260809a: Einstein Probe detection of an X-ray transient
- EP260806a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260806a: Liverpool Telescope observations of the counterpart show a blue colour
- EP260731a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260806a: Einstein Probe detection of an X-ray transient
- GRB 260802A / EP J223759.5+521421: EP-FXT follow-up observation
- The EP-WXT trigger 01709277420 is likely a flaring star
- EP260731a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709277130 (EP260729a): refined EP-WXT analysis and association with a flaring star
- EP 260729a: Ondrejov D50 optical detection supports stellar flare origin
- EP260729a: Einstein Probe detection of an X-ray transient
- EP260728a: EP-FXT follow-up observation
- EP260728a: Einstein Probe detection of a fast X-ray transient
- EP260727a: 1.5m OSN optical counterpart detection
- EP260727a:refined analysis of the EP-WXT and EP-FXT observation
- EP260727a: Liverpool Telescope confirmation of optical counterpart
- EP260727a: Einstein Probe detection of an X-ray transient
- EP260723a: further EP-FXT follow-up observation
- EP260725a: EP-FXT follow-up observation and association with a bright flaring star
- EP260725a: EP-WXT detection of an X-ray transient
- EP260723a: Continued Liverpool Telescope observations suggest hours long optical plateau or rebrightening
- EP260723a: EP-FXT follow-up observation
- EP260723a: Liverpool Telescope likely optical counterpart
- EP260723a: EP-WXT detection of a fast X-ray transient
- GRB 260718A: EP-FXT follow-up observation
- EP260713a: Einstein Probe detection of an X-ray transient
- EP260711a: EP-FXT follow-up observation
- EP260711a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
- EP260707a is not a real source
- EP260707a: Einstein Probe detection of an X-ray transient
- GRB 260706A: EP-FXT follow-up observation
- The EP-WXT trigger 01709274151 is likely a flaring star
- The EP-WXT trigger 01709274141 is likely a flaring star
- The EP-WXT trigger 01709274014 is likely a flaring star
- GRB 260704A: EP-FXT follow-up observation
- EP260703a: EP-FXT follow-up observation
- EP260703a: EP-WXT detection of a fast X-ray transient
- EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
- EP260628a: EP-FXT follow-up observation
- EP260628a: EP-WXT detection of a fast X-ray transient
- The EP-WXT trigger 01709272671 is likely a flaring star
- EP260626a: EP-FXT follow-up observation
- EP260626a: Liverpool Telescope upper limits
- EP260626a: EP-WXT detection of a fast X-ray transient
- EP260623a:refined analysis of the EP-WXT and EP-FXT observation
- EP260623a: Optical follow-up observations with Kinder
- EP260623a: SVOM/VT optical observations
- EP260623a: Las Cumbres discovery of the optical counterpart
- EP260623a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709271197 is likely a flaring star
- EP260618a: EP-FXT follow-up observation
- EP260618a: EP-WXT detection of an X-ray transient
- EP260616a/GRB 260616B: EP-FXT follow-up observation
- GRB 260616B: CALET Gamma-Ray Burst Monitor detection
- EP260616a: EP-WXT detection of a fast X-ray transient
- The EP-WXT trigger 01709270148 is likely a flaring star
- The EP-WXT trigger 01709269893 is likely a flaring star
- The EP-WXT trigger 01709269488 is likely a flaring star
- IceCube-260610A: EP-FXT follow-up observation
- The EP-WXT trigger 01709269176 is likely a flaring star
- EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
- EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
- EP260610b: SVOM/VT optical confirmation with blue color
- EP260610a: SVOM/VT optical upper limits
- EP260610b: Einstein Probe detection of an X-ray transient
- EP260610a: Einstein Probe detection of a fast X-ray transient
- EP260605a: EP-FXT follow-up observation
- EP260605a: Einstein Probe detection of a fast X-ray transient
- The EP-WXT trigger 01709267001 is likely a flaring star