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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"

24278 results found.

  1. Fermi trigger No 801135305: Global MASTER-Net observations report
  2. Fermi GRB 260522A: Global MASTER-Net observations report
  3. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  4. GRB 260522A: Fermi-LAT detection
  5. GRB 260519C: SVOM/GRM observation
  6. GRB 260522A: Fermi GBM Final Real-time Localization
  7. Konus-Wind detection of GRB 260519C
  8. GRB 260520B: Fermi GBM Final Localization
  9. GRB 260509A: SVOM/ECLAIRs refined analysis
  10. GRB 260520A: Fermi GBM Final Localization
  11. GRB 260519D: Fermi GBM Final Localization Correction
  12. GRB 260519C: NuSTAR detection of prompt emission
  13. Konus-Wind detection of GRB 260518A
  14. GRB 260519B: Fermi GBM Final Localization
  15. GRB 260519A: Fermi GBM Final Localization
  16. GRB 260516D: SVOM/ECLAIRs refined analysis
  17. GRB 260515A: SVOM/ECLAIRs refined analysis
  18. GRB 260516D: EP-FXT follow-up observation
  19. GRB 260516D: LCO optical observations
  20. GRB 260516D: GROWTH-India Telescope optical detection
  21. GRB 260516D: SVOM/VT optical bright candidate
  22. Fermi GRB 260516C: Global MASTER-Net observations report
  23. SVOM GRB260516D: Global MASTER-Net observations report
  24. GRB 260516D: SVOM possible detection of a burst
  25. GRB 260516C: Fermi GBM Final Real-time Localization
  26. Konus-Wind detection of GRB 260515A
  27. GRB 260515A: EP-FXT follow-up observation
  28. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  29. EP260514a: NOT optical counterpart confirmation
  30. EP260514a: TRT optical counterpart candidate
  31. EP260514a: SVOM/VT optical candidate
  32. Fermi GRB 260516B: Global MASTER-Net observations report
  33. GRB 260516B: Fermi GBM Final Real-time Localization
  34. GRB 260515A: SVOM/VT optical observations
  35. GRB 260516A: Fermi GBM Final Real-time Localization
  36. GRB 260515A: LCO optical observations
  37. SVOM GRB 260515A: Global MASTER-Net observations report
  38. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  39. GRB 260515A: SVOM/VT optical candidate from VHF data
  40. GRB 260515A: JinShan optical counterpart candidate
  41. GRB 260515A: SVOM detection of a burst
  42. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  43. EP260514a: GROWTH-India Telescope optical upper limit
  44. GRB 260511B: NOT optical observations
  45. Konus-Wind detection of GRB 260512A
  46. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  47. GRB 260511B: GMG Optical Upper Limit
  48. EP260514a: Global MASTER-Net observations report
  49. IPN triangulation of GRB 260512A
  50. GRB 260511B: Mephisto multi-band optical followup
  51. Fermi GRB 260514A: Global MASTER-Net observations report
  52. The EP-WXT trigger 01709262077 is likely a flaring star
  53. GRB 260514A: Fermi GBM Final Real-time Localization
  54. EP260512a: Global MASTER-Net observations report
  55. Fermi GRB 260513A: Global MASTER-Net observations report
  56. Fermi GRB 260512A: Global MASTER-Net observations report
  57. GRB 260513A: Fermi GBM Final Real-time Localization
  58. GRB 260509A: SVOM/VT optical observations
  59. Konus-Wind detection of GRB 260511B
  60. The EP-WXT trigger 01709262036 is likely a flaring star
  61. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  62. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  63. GRB 260512A: NuSTAR detection of prompt emission
  64. GRB 260512A: Fermi GBM Final Real-time Localization
  65. Konus-Wind detection of GRB 260511A
  66. GRB 260511A: EP-FXT follow-up observation
  67. GRB 260511B: EP-FXT follow-up observation
  68. GRB 260511B: LCO optical counterpart detection
  69. GRB 260511A: SVOM/VT optical observations
  70. GRB 260511B: LCO optical observations
  71. GRB 260511B: GOTO optical counterpart detection
  72. GRB 260511B: SVOM/VT optical observations
  73. GRB 260510B: EP-FXT follow-up observation
  74. GRB 260510C: Fermi GBM Observation
  75. GRB 260511A: REM near-infrared detection
  76. GRB 260511B: GROWTH-India Telescope optical observations
  77. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  78. GRB 260511B: NuSTAR detection of prompt emission
  79. GRB 260511A: NuSTAR detection of prompt emission
  80. GRB 260511B: Fermi GBM Detection
  81. GRB 260511C: Fermi GBM Final Real-time Localization
  82. GRB 260511B: SVOM/VT optical observation with VHF data
  83. GRB 260511B: TRT optical observation
  84. GRB 260510B: SVOM/ECLAIRs refined analysis
  85. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  86. GRB 260511A: Fermi GBM Detection
  87. GRB 260511B SVOM/C-GFT optical counterpart detection
  88. GRB 260511A: UTGO H50 optical afterglow observation
  89. GRB 260511B: SVOM detection of a burst
  90. GRB 260511B: Fermi GBM Final Real-time Localization
  91. GRB 260510C: EP-FXT follow-up observation
  92. GRB 260510C: SVOM/VT optical counterpart confirmation
  93. GRB 260511A: SVOM/VT optical observation with VHF data
  94. Fermi GRB 260511A: Global MASTER-Net observations report
  95. GRB 260511A: LCO optical afterglow detection
  96. GRB 260511A: TRT optical counterpart detection
  97. GRB 260511A: SVOM detection of a bright burst
  98. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  99. GRB 260511A: Fermi GBM Final Real-time Localization
  100. GRB 260510B: SVOM/VT optical upper limits

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