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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').
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"

27015 results found.

  1. GRB 260213A: GECAM-B observation of a short burst
  2. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  3. GRB 260216A: Fermi GBM Final Real-time Localization
  4. EP260214b: Liverpool Telescope optical observations
  5. EP260214b: Optical upper limit with Kinder observations
  6. EP260214a: Optical upper limits with Kinder observations
  7. EP260214b: EP-FXT follow-up observation
  8. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  9. EP260214b: DDOTI Optical Detection
  10. EP260214b: GROWTH-India Telescope optical upper limit
  11. EP260214a: VLT near-infrared observation
  12. EP260214b: SVOM/VT optical observation
  13. EP260214a: NOT optical upper limits
  14. EP260214a: COLIBRÍ optical upper limits
  15. EP260214b: OHP/T120 optical observations
  16. EP260214a: refined analysis of the EP-FXT observation
  17. EP260214b: LCO optical counterpart detection
  18. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  19. GRB 260211A: SVOM/VT optical counterpart
  20. EP260214b: COLIBRÍ optical observations
  21. EP260214a: SVOM/VT optical upper limits
  22. EP260214b: NOT optical counterpart detection
  23. EP260214b: Einstein Probe detection of a fast X-ray transient
  24. EP260214a: Global MASTER-Net observations report
  25. EP260214a: Einstein Probe detection of an X-ray transient
  26. GRB 260212A: Fermi GBM Observation
  27. EP260213a: Global MASTER-Net observations report
  28. EP260213a: COLIBRÍ optical upper limits
  29. GRB 260212A: GECAM-B observation
  30. EP260213a: Optical upper limits with Kinder observations
  31. EP260213a: SVOM/VT optical upper limit
  32. EP260213a: NUTTelA-TAO Early Optical Limits
  33. EP260213a: SVOM/C-GFT upper limit
  34. EP260213a: refined analysis of the EP-FXT observation
  35. EP260213a: Einstein Probe detection of a fast X-ray transient
  36. EP/WXT 01709258378: NOT optical upper limits
  37. GRB 260212A: SVOM/GRM observation of a long burst
  38. GRB 260213B: Fermi GBM Final Localization
  39. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  40. GRB 260211A - SVOM/ECLAIRs refined analysis
  41. GRB 260204A: SVOM/ECLAIRs refined analysis
  42. GRB 260213A: Fermi GBM Final Localization
  43. GRB 260211A: EP-FXT follow-up observation
  44. GRB 260211A: SVOM/VT optical observation
  45. GRB 260211A: GOTO optical upper limit
  46. Fermi GRB 260212A: Global MASTER-Net observations report
  47. GRB 260212A: Fermi GBM Final Real-time Localization
  48. GRB 260210A: SVOM/GRM observation
  49. Fermi GBM Sub-Threshold Detection of GRB 260211A
  50. GRB 260128B: SVOM/ECLAIRs refined analysis
  51. GRID detection of GRB 260207B
  52. GRB 260211A: LCO optical upper limits
  53. GRB260131A/B: 3.6m DOT Optical Observations
  54. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  55. Fermi trigger No 792537871: Global MASTER-Net observations report
  56. GRB 260211A: SVOM detection of a burst
  57. GRB 260208A: Swift UVOT detection
  58. EP260209a: COLIBRÍ optical upper limit
  59. Fermi GRB 260210C: Global MASTER-Net observations report
  60. EP260209a: LCO optical upper limits
  61. EP260210a: Global MASTER-Net observations report
  62. EP260210a: refined analysis of the EP-FXT observation
  63. EP260209a: Global MASTER-Net observations report
  64. GRB 260208A: LCO detection of the optical counterpart
  65. EP260209a: Einstein Probe detection of a fast X-ray transient
  66. EP260210a: Optical upper limits with Kinder observations
  67. IPN triangulation of GRB 260207B (short/hard with EE)
  68. GRB 260210C: Fermi GBM Final Real-time Localization
  69. GRB 260210B: Fermi GBM Final Real-time Localization
  70. EP260210a: SVOM/VT optical upper limit
  71. EP260210a: COLIBRÍ optical upper limit
  72. EP260210a: SVOM/C-GFT upper limit
  73. GRB 260208B: refined analysis of the EP-FXT observation
  74. EP260210a: Einstein Probe detection of an X-ray transient
  75. GRB 260208C: SVOM/GRM observation
  76. GRB260208A: Liverpool Telescope optical follow-up observations
  77. GRB 260208A: Fermi GBM Observation
  78. Fermi GRB 260209A: Global MASTER-Net observations report
  79. GRB 260208B: Swift-XRT observations
  80. GRB 260204A: Swift/UVOT Upper Limits
  81. GRB 260208B: COLIBRÍ optical observations
  82. GRB 260208A: 1.3m DFOT optical detection
  83. GRB 260208A: COLIBRÍ optical observations
  84. GRB 260208B: EP-FXT observation
  85. GRB 260208A: Liverpool Telescope optical detection
  86. Fermi GRB 260208C: Global MASTER-Net observations report
  87. GRB 260208B: SVOM/VT optical candidate
  88. GRB 260208A: GECAM-B observation of a bright burst
  89. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  90. GRB 260209A: Fermi GBM Final Real-time Localization
  91. GRB 260208A: SVOM/VT optical observation
  92. Fermi GRB 260208D: Global MASTER-Net observations report
  93. GRB 260208D: Fermi GBM Final Real-time Localization
  94. GRB 260208B: SVOM/GRM observation of a bright burst
  95. GRB 260208B: Fermi GBM Detection
  96. LAT GRB 260208B: Global MASTER-Net observations report
  97. GRB 260208B: Fermi-LAT detection
  98. GRB 260208C: Fermi GBM Final Real-time Localization
  99. GRB 260208A: Fermi-LAT detection
  100. GRB 260207B: GECAM-B observation

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