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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

2449 results found.

  1. EP260602a: Optical upper limits with Kinder observations
  2. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  3. EP260602a: Einstein Probe detection of a fast X-ray transient
  4. GRB 260601B/EP260601a: SVOM/VT optical observations
  5. GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
  6. EP260601a: Einstein Probe detection of an X-ray transient
  7. EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
  8. GRB 260601A: Glowbug gamma-ray detection of a short burst
  9. GRB 260531B: Glowbug gamma-ray detection
  10. GRB 260516D: VLA radio detection
  11. GRB 260601A: Fermi GBM Observation
  12. EP260530a/AT 2026nwl: COLIBRÍ optical observations
  13. GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
  14. GRB 260527A/EP260527a: Glowbug gamma-ray detection
  15. Fermi GRB 260601A: Global MASTER-Net observations report
  16. GRB 260601A: Fermi GBM Final Real-time Localization
  17. GRB 260531B: GECAM-B observation
  18. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  19. The EP-WXT trigger 01709266272 is likely a flaring star
  20. GRB 260531C: Fermi GBM Final Localization Correction
  21. Fermi Gamma-ray Burst Monitor trigger 801900520/260531256 is not a GRB
  22. AT2026nik: EP-FXT X-ray counterpart
  23. Fermi trigger No 801900520: Global MASTER-Net observations report
  24. GRB 260531B: Fermi GBM Final Real-time Localization
  25. GRB 260531A: MAXI/GSC detection
  26. AT 2026nuz: COLIBRÍ optical observations
  27. EP260527a/GRB 260527A: further FTW optical and NIR observations
  28. GRB 260530B: SVOM/GRM detection of a possible bright short GRB
  29. GRB 260530A: Fermi GBM Final Real-time Localization
  30. GRB 260527A / EP260527a: VLA radio detection
  31. EP260527a/GRB 260527A: optical upper limit with Kinder observations
  32. GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
  33. GRB 260529A: GOTO tentative optical afterglow candidate
  34. GRB 260527A/EP260527a: Insight-HXMT detection
  35. Fermi GRB 260529A: Global MASTER-Net observations report
  36. GRB 260529A: Fermi GBM Final Real-time Localization
  37. EP260526a: SVOM/VT optical upper limits
  38. GRB 260527A/EP260527a: Gemini GMOS-S Optical Observations
  39. EP260527a / GRB 260527A: NOT optical observations
  40. GRB 260527A/EP260527a: FTW optical and NIR observations
  41. EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
  42. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  43. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  44. GRB 260526A: GECAM-B observation
  45. EP260527a: SVOM/VT optical observation
  46. EP260527a: COLIBRÍ optical detection
  47. EP260527a: Einstein Probe detection of a fast X-ray transient
  48. The EP-WXT trigger 01709266172 is likely a flaring star
  49. The EP-WXT trigger 01709266147 is likely a flaring star
  50. Fermi trigger No 801580882: Global MASTER-Net observations report
  51. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  52. EP260526a: LCO optical upper limits
  53. EP260526a: Einstein Probe detection of a fast X-ray transient
  54. GRB 260525A: AstroSat CZTI detection
  55. EP260526.405: COLIBRÍ optical upper limits
  56. The EP-WXT trigger 01709266106 is not a real source
  57. Fermi GRB 260526A: Global MASTER-Net observations report
  58. GRB 260526A: Fermi GBM Final Real-time Localization
  59. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  60. EP-WXT 01709266106: NOT optical upper limits
  61. Fermi GRB 260525A: Global MASTER-Net observations report
  62. GRB 260525A: Fermi GBM Final Real-time Localization
  63. GRB 260523B: AstroSat CZTI detection
  64. GRB 260523B: GECAM-B observation
  65. Fermi GRB 260523A: Global MASTER-Net observations report
  66. GRB 260523B: Fermi GBM Final Real-time Localization
  67. GRB 260523A: Fermi GBM Final Real-time Localization
  68. GRB 260522A: Fermi GBM Observation
  69. GRB 260522B: NuSTAR detection of prompt emission
  70. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  71. GRB 260522B: Fermi GBM Final Real-time Localization
  72. GRB 260522A: GOTO optical upper limit
  73. Fermi trigger No 801135305: Global MASTER-Net observations report
  74. Fermi GRB 260522A: Global MASTER-Net observations report
  75. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  76. GRB 260522A: Fermi-LAT detection
  77. GRB 260519C: SVOM/GRM observation
  78. GRB 260522A: Fermi GBM Final Real-time Localization
  79. GRB 260520B: SVOM/GRM observation
  80. GRB 260411B: TERI Gamma-ray detection
  81. GRB 260407A: TERI Gamma-ray detection
  82. GRB 260307A: TERI Gamma-ray detection
  83. GRB 260225D: TERI Gamma-ray detection
  84. GRB 260428A: TERI Gamma-ray detection
  85. GRB 260520B: Fermi GBM Final Localization
  86. GRB 260509A: SVOM/ECLAIRs refined analysis
  87. GRB 260520A: Fermi GBM Final Localization
  88. GRB 260519D: Fermi GBM Final Localization Correction
  89. GRB 260519C: NuSTAR detection of prompt emission
  90. GRB 260519B: Fermi GBM Final Localization
  91. GRB 260519A: Fermi GBM Final Localization
  92. GRB 260518A: AstroSat CZTI detection of a long burst
  93. GRB 260516D: SVOM/ECLAIRs refined analysis
  94. GRB 260515A: SVOM/ECLAIRs refined analysis
  95. GRB 260421B: radio detection with the VLA
  96. GRID detection of GRB 260511A
  97. GRB 260509A: CrAO ZTSh optical upper limit
  98. GRB 260516D: EP-FXT follow-up observation
  99. GRB 260516D: GOTO optical counterpart detection
  100. GRB 260516D: LCO optical observations

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