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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').

49 results found.

  1. GRB 250327B: Kilonova-Catcher Observations
  2. GRB 250329B: CAHA 2.2m telescope optical limit
  3. GRB 250328A: 1.6m Mephisto optical observations
  4. GRB 250329B: 1.6m Mephisto Optical Upper Limits
  5. GRB 250327B: MASTER detection of OT rebrightening
  6. GRB 250327B: 1.6m Mephisto optical observations
  7. EP250308a: 1.6m Mephisto optical upper limits
  8. GRB 250226A: GRANDMA Optical Observations
  9. GRB 250226A: Fermi GBM Observation
  10. EP250226a/GRB 250226A: 1.6m Mephisto observations
  11. EP250223a: 1.6m Mephisto and 50cm array observations
  12. GRB 250221A: 1.6m Mephisto optical detection
  13. EP250220a: 1.6m Mephisto observations
  14. GRB 250219A: 1.6m Mephisto optical upper limits
  15. GRB 250215A/EP250215a: 1.6m Mephisto optical observation report
  16. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  17. GRB 250109A / EP250109a: Mephisto optical upper limits
  18. EP250108a: Mephisto detection
  19. GRB 250103A: 1.6m Mephisto optical observations
  20. GRB 241228B: Fermi-LAT detection
  21. GRB 250101A: 1.6m Mephisto multi-band optical followup
  22. GRB 241228B: Multiband optical monitoring with 1.6m Mephisto
  23. EP241217a: 1.6m Mephisto multi-band optical observations
  24. GRB 241217a/EP241217B: 1.6m Mephisto optical upper limits
  25. EP241201a: 1.6m Mephisto Optical Upper Limits
  26. EP241126a: 1.6m Mephisto Optical Upper Limits
  27. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  28. GRB 241112B: Mephisto further optical observations
  29. GRB 241115A: Mephisto upper limits
  30. GRB 241113B: Mephisto upper limits
  31. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  32. GRB 241112B: Optical afterglow detection confirmation in revisiting the Mephisto data
  33. GRB 241112B: Mephisto optical upper limits
  34. EP241021a: Optical rebrightening observations with Mephisto
  35. GRB 241030A: Multiband optical detection with Mephisto
  36. GRB 241029A: GOTO optical afterglow detection
  37. GRB 241029A: Mephisto observations
  38. GRB 241018A/sb24101802: Mephisto optical upper limit
  39. GRB 241017A/sb24101702: Mephisto optical upper limit
  40. EP240913a/GRB 240913C: 1.6m Mephisto observations
  41. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  42. GRB 240828B: Mephisto optical upper limit
  43. GRB 240825A: MASTER optical counterpart observation
  44. GRB 240825A: 1.6m Mephisto multi-band detection
  45. GRB 240811A: Upper limits with Mephisto
  46. GRB 240805B: Optical detection with 1.6m Mephisto
  47. LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
  48. GRB231111A: MDM 2.4m Hiltner Telescope Observation
  49. GRB231111A: Optical follow-up observations with Mephisto

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