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"3295 results found.
- The EP-WXT trigger 01709320726 is likely a flaring star
- EP260924a: EP-FXT follow-up observation
- Konus-Wind detection of GRB 260924A
- EP260924a: J-band upper limit with WINTER
- EP260924a: EP-WXT detection of an X-ray transient
- Konus-Wind detection of GRB 260922A
- Konus-Wind detection of GRB 260921A (correction to GCN 45722)
- Konus-Wind detection of GRB 260921A (possible merger-origin)
- The EP-WXT trigger 01709319842 is likely a flaring star
- Konus-Wind detection of GRB 260810A
- EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
- EP Alert 260921.58: Global MASTER-Net observations report
- The EP-WXT trigger 01709319528 is likely a flaring star
- EP260920a: VLT/HAWK-I near-infrared candidate
- EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
- EP260920b: refined analysis of the EP-WXT and EP-FXT observations
- EP260920b: LCO optical counterpart detection
- The EP-WXT trigger 01709318601 is likely a flaring star
- EP Alert 260921.01: Global MASTER-Net observations report
- EP260920b: Global MASTER-Net observations report
- EP260920b: Einstein Probe detection of an X-ray transient
- EP Alert 260920.66: Global MASTER-Net observations report
- EP-WXT detected a brightening of HMXB LS V +44 17
- EP260920a: NOT early time optical upper limits
- EP260920a: NOT optical upper limits
- EP260920a: SVOM/VT optical upper limits
- EP260917a: Global MASTER-Net observations report
- EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
- EP260920a: COLIBRÍ optical upper limits
- EP260917b: EP-FXT non-detection and upper limit
- EP260920a: LCO optical counterpart candidate
- EP260920a: Einstein Probe detection of an X-ray transient
- EP Alert 260919.40: Global MASTER-Net observations report
- GRB 260915A: VLT optical and near-infrared upper limits
- EP260917a: refined analysis of the EP-FXT observations
- The EP-WXT trigger 01709318491 is likely a flaring star
- EP260917a: SVOM/VT optical upper limits
- GRB 260918A: SVOM/C-GFT optical upper limits
- EP Alert 260918.62: Global MASTER-Net observations report
- EP Alert 260918.24: Global MASTER-Net observations report
- Konus-Wind detection of GRB 260916B (short/hard)
- The EP-WXT trigger 01709318279 is likely a flaring star
- GRB 260918A: SVOM/VT optical upper limits
- GRB 260918A: EP-FXT follow-up observation
- EP260917b: EP-WXT detection of an X-ray transient
- EP Alert 260917.32: Global MASTER-Net observations report
- GRB 260917B: EP-FXT follow-up observation
- GRB 260915A: Swift-XRT afterglow detection
- EP260917a: Einstein Probe detection of an X-ray transient
- The EP-WXT trigger 01709317235 is likely a flaring star
- GRB 260914A: SVOM/ECLAIRs refined analysis
- GRB 260909A: Swift-XRT observations
- GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
- GRB 260915A: SVOM/C-GFT optical upper limits
- GRB 260915A: EP-FXT follow-up observation
- GRB 260915A: SVOM/VT refined early optical upper limits
- GRB 260915A: EP-FXT follow-up observation
- EP Alert 260914.53: Global MASTER-Net observations report
- GRB 260914A: EP-FXT follow-up observation
- GRB 260818A: Continued ATCA observations
- GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
- GRB 260909A: CrAO and AbAO optical upper limits
- GRB 260909A: KAIT optical upper limit
- GRB 260909A: VLT optical and near-infrared upper limits
- EP Alert 260909.53: Global MASTER-Net observations report
- GRB 260909A: EP-FXT follow-up observation
- The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
- EP Alert 260908.60: Global MASTER-Net observations report
- GRB 260903A: SAO RAS optical upper limit
- The EP-WXT trigger 01709305715 is likely a flaring star
- EP260903a: EP-FXT follow-up observation
- EP Alert 260905.11: Global MASTER-Net observations report
- The EP-WXT trigger 01709302592 is likely a flaring star
- EP Alert 260903.47: Global MASTER-Net observations report
- GRB 260903A: SAO RAS optical observations
- EP260903a: EP-WXT detection of a fast X-ray transient
- EP Alert 260903.62: Global MASTER-Net observations report
- GRB 260903A: EP-FXT follow-up observation
- EP260901a: SVOM/VT optical upper limits
- EP260901a: EP-FXT follow-up observation
- Konus-Wind detection of GRB 260829A
- GRB 260818A: ATCA detection of a candidate radio counterpart
- EP260830a: EP-FXT follow-up observation
- EP260901a: Global MASTER-Net observations report
- EP260901a: EP-WXT detection of a fast X-ray transient
- GRB 260831B: EP-FXT follow-up observation
- EP260830a: Global MASTER-Net observations report
- EP260830a: EP-WXT detection of a fast X-ray transient
- EP260727a: ATCA 10 GHz detection
- GRB 260818B: Further EP-FXT observation
- The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
- GRB 260818B: SVOM/VT optical upper limit and continuous observations
- GRB 260808B: SAO RAS observations of the optical rebrightening
- EP260822a: Global MASTER-Net observations report
- EP Alert 260820.31: Global MASTER-Net observations report
- GRB 260807A: EP-FXT follow-up observations
- 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