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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"

27770 results found.

  1. EP260610a: SVOM/VT optical upper limits
  2. EP260610b: Einstein Probe detection of an X-ray transient
  3. Konus-Wind detection of GRB 260601A
  4. IPN triangulation of GRB 260601A (short/hard)
  5. GRB 260610A: Fermi GBM Final Real-time Localization
  6. EP260610a: Einstein Probe detection of a fast X-ray transient
  7. GRB 260609A: Fermi GBM Final Localization
  8. Konus-Wind detection of GRB 260604C
  9. GRB 260604C: AstroSat CZTI detection
  10. IPN triangulation of GRB 260601B / EP260601a
  11. GRB 260604C: SVOM/ECLAIRs refined analysis
  12. Konus-Wind detection of GRB 260607B
  13. GRB 260608C: Fermi GBM Final Real-time Localization
  14. GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
  15. GRB 260608B: Fermi GBM Final Localization
  16. GRB 260607B: AstroSat CZTI detection
  17. GRB 260608A: SVOM detection of a burst
  18. GRB 260608A: Fermi GBM Final Real-time Localization
  19. EP260605a: EP-FXT follow-up observation
  20. GRB 260604A: SVOM/GRM detection
  21. GRB 260607B: Fermi-LAT detection
  22. GRB 260607B: Fermi GBM Final Localization Correction
  23. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  24. GRB 260607A: Fermi GBM Final Real-time Localization
  25. GRB 260604B: SVOM/GRM detection
  26. GRB 260605A: Insight-HXMT/HE detection
  27. EP260605a: Einstein Probe detection of a fast X-ray transient
  28. GRB 260604A: Glowbug gamma-ray detection
  29. GRB 260604C: Liverpool Telescope optical detection
  30. EP260602d: EP-FXT follow-up observation
  31. EP260602c: EP-FXT follow-up observation
  32. GRB 260601B / EP260601a: AstroSat CZTI detection
  33. GRB 260527A/EP260527a: 6 GHz VLA observations
  34. GRB 260604C: Correction to GCN 44828
  35. GRB 260604C: Kilonova-Catcher optical afterglow detection
  36. GRB 260604C: LAST detection of optical counterpart candidate
  37. GRB 260604C: MASTER OT J145749.59+284903.0 optical counterpart discovery
  38. GRB 260604C: SVOM detection of a long burst
  39. GRB 260604C: Fermi GBM Final Real-time Localization
  40. GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
  41. GRB 260604B: Fermi GBM Final Real-time Localization
  42. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  43. EP260602a: EP-FXT follow-up observation
  44. EP260603a: Einstein Probe detection of a fast X-ray transient
  45. EP260602d: Optical Upper limits with kinder observations
  46. GRB 260604A: Fermi GBM Final Real-time Localization
  47. EP260602b: Liverpool Telescope observations
  48. GRB 260603B: Fermi GBM Final Localization
  49. Konus-Wind detection of GRB 260601B/EP260601a
  50. EP260602b: EP-FXT follow-up observation
  51. GRB 260601B/EP260601a: Glowbug gamma-ray detection
  52. EP260602d: Einstein Probe detection of a fast X-ray transient
  53. EP260602c: Einstein Probe detection of a fast X-ray transient
  54. EP260602a: COLIBRÍ optical observations
  55. GRB 260603A: SVOM detection of a burst
  56. EP260602b: Einstein Probe detection of a fast X-ray transient
  57. GRB 260601B/EP260601a: Insight-HXMT detection
  58. EP-WXT trigger 01709266414 (EP260602b): JinShan optical counterpart detection
  59. GRB 260602B: Fermi GBM Final Localization
  60. GRB 260602A: Fermi GBM Final Real-time Localization
  61. GRB 260601B: CALET Gamma-Ray Burst Monitor detection
  62. EP260602a: Optical upper limits with Kinder observations
  63. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  64. EP260602a: Einstein Probe detection of a fast X-ray transient
  65. GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
  66. EP260601a: Einstein Probe detection of an X-ray transient
  67. EP-WXT trigger 01709266307 (EP260601a): JinShan optical counterpart detection
  68. GRB 260601A: Glowbug gamma-ray detection of a short burst
  69. GRB 260531B: Glowbug gamma-ray detection
  70. GRB 260516D: VLA radio detection
  71. GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
  72. GRB 260527A/EP260527a: Glowbug gamma-ray detection
  73. GRB 260601A: Fermi GBM Final Real-time Localization
  74. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  75. GRB 260531C: Fermi GBM Final Localization Correction
  76. AT2026nik: EP-FXT X-ray counterpart
  77. GRB 260531B: Fermi GBM Final Real-time Localization
  78. GRB 260531A: MAXI/GSC detection
  79. IPN triangulation of GRB 260527A / EP260527a
  80. GRB 260530B: SVOM/GRM detection of a possible bright short GRB
  81. GRB 260530A: Fermi GBM Final Real-time Localization
  82. GRB 260527A / EP260527a: VLA radio detection
  83. GRB 260527A/EP260527a: Insight-HXMT detection
  84. GRB 260529A: Fermi GBM Final Real-time Localization
  85. EP260526a: SVOM/VT optical upper limits
  86. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  87. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  88. EP260527a/GRB 260527A: EP-FXT follow-up observation
  89. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  90. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  91. EP260526a: EP-FXT follow-up observation
  92. EP260527a: COLIBRÍ optical detection
  93. EP260527a: Einstein Probe detection of a fast X-ray transient
  94. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  95. EP260526a: LCO optical upper limits
  96. EP260526a: Einstein Probe detection of a fast X-ray transient
  97. GRB 260525A: AstroSat CZTI detection
  98. GRB 260526A: Fermi GBM Final Real-time Localization
  99. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  100. GRB 260525A: Fermi GBM Final Real-time Localization

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