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"1103 results found.
- EP#01709320865: Swift-XRT observations
- EP261003a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- Trigger_21915: Swift ToO observations
- EP261003a: Einstein Probe detection of an X-ray transient
- Fermi GBM Detection of GRB 260919A / EP260920a
- The EP-WXT trigger 01709320790 is likely a flaring star
- EP260927a: Einstein Probe detection of a fast X-ray transient
- The EP-WXT trigger 01709320726 is likely a flaring star
- EP260924a: EP-FXT follow-up observation
- EP260924a: EP-WXT detection of an X-ray transient
- The EP-WXT trigger 01709319842 is likely a flaring star
- Trigger_21914: Swift ToO observations
- The EP-WXT trigger 01709319528 is likely a flaring star
- EP260920b: refined analysis of the EP-WXT and EP-FXT observations
- The EP-WXT trigger 01709318601 is likely a flaring star
- EP260920b: Einstein Probe detection of an X-ray transient
- EP-WXT detected a brightening of HMXB LS V +44 17
- EP260920a: NOT optical upper limits
- EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260917b: EP-FXT non-detection and upper limit
- EP260920a: LCO optical counterpart candidate
- EP260920a: Einstein Probe detection of an X-ray transient
- EP260917a: refined analysis of the EP-FXT observations
- The EP-WXT trigger 01709318491 is likely a flaring star
- EP260806a: Yamaguchi Interferometer radio detections
- The EP-WXT trigger 01709318279 is likely a flaring star
- GRB 260918A: EP-FXT follow-up observation
- EP260917b: EP-WXT detection of an X-ray transient
- GRB 260917B: EP-FXT follow-up observation
- EP260917a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709317235 is likely a flaring star
- GRB 260915A: EP-FXT follow-up observation
- GRB 260914A: EP-FXT follow-up observation
- EP260806a: VLA+ALMA radio detections
- GRB 260909A: EP-FXT follow-up observation
- EP260806a: NOEMA detection
- The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
- The EP-WXT trigger 01709305715 is likely a flaring star
- EP260903a: EP-FXT follow-up observation
- The EP-WXT trigger 01709302592 is likely a flaring star
- EP260903a: EP-WXT detection of a fast X-ray transient
- GRB 260903A: EP-FXT follow-up observation
- EP260901a: EP-FXT follow-up observation
- EP260830a: EP-FXT follow-up observation
- EP260901a: EP-WXT detection of a fast X-ray transient
- GRB 260831B: EP-FXT follow-up observation
- EP260830a: EP-WXT detection of a fast X-ray transient
- 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