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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"

27767 results found.

  1. IPN triangulation of GRB 260601A (short/hard)
  2. GRB 260610A: Fermi GBM Final Real-time Localization
  3. EP260610a: Einstein Probe detection of a fast X-ray transient
  4. GRB 260609A: Fermi GBM Final Localization
  5. Konus-Wind detection of GRB 260604C
  6. GRB 260604C: AstroSat CZTI detection
  7. IPN triangulation of GRB 260601B / EP260601a
  8. GRB 260604C: SVOM/ECLAIRs refined analysis
  9. Konus-Wind detection of GRB 260607B
  10. GRB 260608C: Fermi GBM Final Real-time Localization
  11. GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
  12. GRB 260608B: Fermi GBM Final Localization
  13. GRB 260607B: AstroSat CZTI detection
  14. GRB 260608A: SVOM detection of a burst
  15. GRB 260608A: Fermi GBM Final Real-time Localization
  16. EP260605a: EP-FXT follow-up observation
  17. GRB 260604A: SVOM/GRM detection
  18. GRB 260607B: Fermi-LAT detection
  19. GRB 260607B: Fermi GBM Final Localization Correction
  20. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  21. GRB 260607A: Fermi GBM Final Real-time Localization
  22. GRB 260604B: SVOM/GRM detection
  23. GRB 260605A: Insight-HXMT/HE detection
  24. EP260605a: Einstein Probe detection of a fast X-ray transient
  25. GRB 260604A: Glowbug gamma-ray detection
  26. GRB 260604C: Liverpool Telescope optical detection
  27. EP260602d: EP-FXT follow-up observation
  28. EP260602c: EP-FXT follow-up observation
  29. GRB 260601B / EP260601a: AstroSat CZTI detection
  30. GRB 260527A/EP260527a: 6 GHz VLA observations
  31. GRB 260604C: Correction to GCN 44828
  32. GRB 260604C: Kilonova-Catcher optical afterglow detection
  33. GRB 260604C: LAST detection of optical counterpart candidate
  34. GRB 260604C: MASTER OT J145749.59+284903.0 optical counterpart discovery
  35. GRB 260604C: SVOM detection of a long burst
  36. GRB 260604C: Fermi GBM Final Real-time Localization
  37. GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
  38. GRB 260604B: Fermi GBM Final Real-time Localization
  39. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  40. EP260602a: EP-FXT follow-up observation
  41. EP260603a: Einstein Probe detection of a fast X-ray transient
  42. EP260602d: Optical Upper limits with kinder observations
  43. GRB 260604A: Fermi GBM Final Real-time Localization
  44. EP260602b: Liverpool Telescope observations
  45. GRB 260603B: Fermi GBM Final Localization
  46. Konus-Wind detection of GRB 260601B/EP260601a
  47. EP260602b: EP-FXT follow-up observation
  48. GRB 260601B/EP260601a: Glowbug gamma-ray detection
  49. EP260602d: Einstein Probe detection of a fast X-ray transient
  50. EP260602c: Einstein Probe detection of a fast X-ray transient
  51. EP260602a: COLIBRÍ optical observations
  52. GRB 260603A: SVOM detection of a burst
  53. EP260602b: Einstein Probe detection of a fast X-ray transient
  54. GRB 260601B/EP260601a: Insight-HXMT detection
  55. EP-WXT trigger 01709266414 (EP260602b): JinShan optical counterpart detection
  56. GRB 260602B: Fermi GBM Final Localization
  57. GRB 260602A: Fermi GBM Final Real-time Localization
  58. GRB 260601B: CALET Gamma-Ray Burst Monitor detection
  59. EP260602a: Optical upper limits with Kinder observations
  60. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  61. EP260602a: Einstein Probe detection of a fast X-ray transient
  62. GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
  63. EP260601a: Einstein Probe detection of an X-ray transient
  64. EP-WXT trigger 01709266307 (EP260601a): JinShan optical counterpart detection
  65. GRB 260601A: Glowbug gamma-ray detection of a short burst
  66. GRB 260531B: Glowbug gamma-ray detection
  67. GRB 260516D: VLA radio detection
  68. GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
  69. GRB 260527A/EP260527a: Glowbug gamma-ray detection
  70. GRB 260601A: Fermi GBM Final Real-time Localization
  71. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  72. GRB 260531C: Fermi GBM Final Localization Correction
  73. AT2026nik: EP-FXT X-ray counterpart
  74. GRB 260531B: Fermi GBM Final Real-time Localization
  75. GRB 260531A: MAXI/GSC detection
  76. IPN triangulation of GRB 260527A / EP260527a
  77. GRB 260530B: SVOM/GRM detection of a possible bright short GRB
  78. GRB 260530A: Fermi GBM Final Real-time Localization
  79. GRB 260527A / EP260527a: VLA radio detection
  80. GRB 260527A/EP260527a: Insight-HXMT detection
  81. GRB 260529A: Fermi GBM Final Real-time Localization
  82. EP260526a: SVOM/VT optical upper limits
  83. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  84. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  85. EP260527a/GRB 260527A: EP-FXT follow-up observation
  86. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  87. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  88. EP260526a: EP-FXT follow-up observation
  89. EP260527a: COLIBRÍ optical detection
  90. EP260527a: Einstein Probe detection of a fast X-ray transient
  91. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  92. EP260526a: LCO optical upper limits
  93. EP260526a: Einstein Probe detection of a fast X-ray transient
  94. GRB 260525A: AstroSat CZTI detection
  95. GRB 260526A: Fermi GBM Final Real-time Localization
  96. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  97. GRB 260525A: Fermi GBM Final Real-time Localization
  98. GRB 260523B: AstroSat CZTI detection
  99. GRB 260523B: Fermi GBM Final Real-time Localization
  100. GRB 260523A: Fermi GBM Final Real-time Localization

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