Skip to main content
New SVOM Notices, Planned Retirement of VOEvent Brokers. See news and announcements

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.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').

36 results found.

  1. GRB 250221A: 1.6m Mephisto optical detection
  2. EP250220a: 1.6m Mephisto observations
  3. GRB 250219A: 1.6m Mephisto optical upper limits
  4. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  5. GRB 250215A / EP250215a: SVOM/VT optical candidate comfirmation
  6. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  7. GRB 250109A / EP250109a: Mephisto optical upper limits
  8. EP250108a: Mephisto detection
  9. GRB 250103A: 1.6m Mephisto optical observations
  10. GRB 250101A: 1.6m Mephisto multi-band optical followup
  11. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  12. EP241217a: 1.6m Mephisto multi-band optical observations
  13. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  14. EP241201a: 1.6m Mephisto Optical Upper Limits
  15. EP241126a: 1.6m Mephisto Optical Upper Limits
  16. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  17. GRB 241112B: Mephisto further optical observations
  18. GRB 241115A: Mephisto upper limits
  19. GRB 241113B: Mephisto upper limits
  20. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  21. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  22. GRB 241112B: Mephisto optical upper limits
  23. EP241021a: Optical rebrightening observations with Mephisto
  24. GRB 241030A: Multiband optical detection with Mephisto
  25. GRB 241029A: Mephisto observations
  26. EP241021a: EP-FXT follow-up observation update
  27. EP241021a: EP detection of a fast X-ray transient
  28. GRB 241018A/sb24101802: Mephisto optical upper limit
  29. GRB 241017A/sb24101702: Mephisto optical upper limit
  30. EP240913a/GRB 240913C: 1.6m Mephisto observations
  31. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  32. GRB 240828B: Mephisto optical upper limit
  33. GRB 240825A: 1.6m Mephisto multi-band detection
  34. GRB 240811A: Upper limits with Mephisto
  35. GRB 240805B: Optical detection with 1.6m Mephisto
  36. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov