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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"

36701 results found.

  1. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  2. GRB 240821B: Fermi GBM Final Localization
  3. Fermi trigger No 745866488: Global MASTER-Net observations report
  4. GRB 240821A: BALROG localization (Fermi Trigger 745958167 / GRB 240821775)
  5. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  6. GRB 240821A: Fermi GBM Final Real-time Localization
  7. GRB 240819A: Swift-XRT observations
  8. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  9. GRB 240820B: SVOM/GRM observation
  10. GRB 240819A: KAIT optical upper limit
  11. Fermi trigger No 745873283: Global MASTER-Net observations report
  12. Fermi trigger No 745871958: Global MASTER-Net observations report
  13. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  14. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  15. GRB 240819A: X-ray follow-up observation with EP-FXT
  16. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  17. GRB 240820A: Fermi GBM Final Real-time Localization
  18. GRB 240819A: Swift ToO observations
  19. GRB 240814A: SVOM/GRM observation
  20. GRB 240814C: SVOM/GRM observation
  21. GRB 240815A: SVOM/GRM observation
  22. GRB 240817A: Fermi GBM Final Real-time Localization
  23. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  24. IBAS Alert n.10856: not a GRB
  25. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  26. EP240816b: KAIT optical upper limit
  27. GRB 240814B: GRBAlpha detection
  28. Fermi trigger No 745501396: Global MASTER-Net observations report
  29. Fermi GRB 240814A: Global MASTER-Net observations report
  30. Fermi GRB 240814C: Global MASTER-Net observations report
  31. Fermi trigger No 745306088: Global MASTER-Net observations report
  32. GRB 240814C: Fermi GBM Final Real-time Localization
  33. Fermi GRB 240814B: Global MASTER-Net observations report
  34. GRB 240812B: SVOM/GRM observation
  35. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  36. GRB 240814B: Fermi GBM Final Real-time Localization
  37. GRB 240814A: Fermi GBM Final Real-time Localization
  38. Fermi trigger No 745220784: Global MASTER-Net observations report
  39. Konus-Wind detection of GRB 240811A
  40. Konus-Wind detection of GRB 240810A
  41. Fermi Gamma-ray Burst Monitor trigger 745220784/240813240 is not a GRB
  42. GRB 240809A: Correction to the VLA source position in GCN 37158
  43. GRB 240810A: SVOM/GRM observation
  44. Fermi Gamma-ray Burst Monitor trigger 240812940/745194848 is not a GRB
  45. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  46. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  47. GRB 240809A: ATA radio non-detection
  48. GRB 240812D: Fermi GBM Final Real-time Localization
  49. GRB 240812C: Fermi GBM Final Real-time Localization
  50. GRB 240809A : RAPAS follow-up observations
  51. GRB 240809A: VLA detection
  52. GRB 240809A: ALMA detection
  53. IPN triangulation of GRB 240810A (short)
  54. GRB 240811A: Swift-BAT refined analysis
  55. GRB 240809A: Swift-BAT refined analysis
  56. GRB 240812B: AstroSat CZTI detection of a long burst
  57. GRB 240811A: Bassano Bresciano Observatory upper limit
  58. GRB 240811A: Swift-XRT refined Analysis
  59. Fermi Gamma-ray Burst Monitor trigger 745135620/240812255 is not a GRB
  60. GRB 240811A: Swift/UVOT Upper Limits
  61. EP240801a: Assy-Turgen optical observations
  62. Fermi GRB 240810A: Global MASTER-Net observations report
  63. Fermi Gamma-ray Burst Monitor trigger 240812094/745121685 is not a GRB
  64. GRB 240812A: Fermi GBM Final Real-time Localization
  65. GRB 240811A: LCOGT Optical Upper Limit
  66. GRB 240811A: Enhanced Swift-XRT position
  67. GRB 240811A: Upper limits with Mephisto
  68. Konus-Wind detection of GRB 240809A
  69. Fermi trigger No 745057312: Global MASTER-Net observations report
  70. Swift GRB 240811A: Global MASTER-Net observations report
  71. GRB 240811A: Swift detection of a burst
  72. Fermi Gamma-ray Burst Monitor trigger 745050426/240811269 is not a GRB
  73. GRB 240810A: Fermi GBM Final Real-time Localization
  74. GRB 240809A: REM detection of the optical afterglow
  75. GRB 240809A: Bassano Bresciano Observatory optical observations
  76. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  77. GRB 240809A: Conclusive redshift from VLT
  78. Fermi-LAT gamma-ray observations of IceCube-240808A
  79. GRB 240809A: KAIT optical observations
  80. GRB 240808A: AstroSat CZTI detection
  81. GRB 240809A: GIT afterglow observations
  82. GRB 240809B: MAXI/GSC detection
  83. GRB 240809A: Swift/UVOT Detection
  84. GRB 240809A: Tentative redshift from NOT
  85. GRB 240809A: Swift-XRT refined Analysis
  86. IPN triangulation of GRB 240807A / EP 240807a
  87. Swift GRB 240809A: Global MASTER-Net observations report
  88. GRB 240809A: JinShan optical observations
  89. GRB 240809A: Enhanced Swift-XRT position
  90. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  91. GRB 240809A: SVOM/GRM observation
  92. GRB 240808A: SVOM/GRM observation
  93. GRB 240807A: SVOM/GRM observation
  94. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  95. EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
  96. EP240807a: STEP/T80S optical limits
  97. GRB 240807B: AstroSat CZTI detection of a short burst
  98. IceCube-240808A - IceCube observation of a high-energy neutrino candidate track-like event
  99. GRB 240801A: GRBAlpha detection
  100. GRB 240807B: Fermi GBM Final Localization

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