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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"

37520 results found.

  1. GRB 240821A: JinShan optical upper limits
  2. GRB 240809A: Mondy and AbAO Optical Observations
  3. GRB 240821A: SVOM/VT follow-up and optical upper limit
  4. GRB 240821A: GMG Optical Upper Limit
  5. Fermi GRB 240821A: Global MASTER-Net observations report
  6. GRB 240821A: Fermi GBM Observation
  7. Fermi trigger No 745964969: Global MASTER-Net observations report
  8. Fermi trigger No 745925274: Global MASTER-Net observations report
  9. GRB 240821A: Swift ToO observations
  10. Fermi trigger No 746019401: Global MASTER-Net observations report
  11. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  12. Fermi trigger No 745935375: Global MASTER-Net observations report
  13. GRB240821A: EIRSAT-1 GMOD Detection
  14. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  15. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  16. Fermi GRB 240821B: Global MASTER-Net observations report
  17. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  18. GRB 240821A: SVOM/GRM observation
  19. GRB 240821A: SVOM/GRM observation
  20. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  21. GRB 240821B: Fermi GBM Final Localization
  22. Fermi trigger No 745866488: Global MASTER-Net observations report
  23. GRB 240821A: BALROG localization (Fermi Trigger 745958167 / GRB 240821775)
  24. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  25. GRB 240821A: Fermi GBM Final Real-time Localization
  26. GRB 240819A: Swift-XRT observations
  27. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  28. GRB 240820B: SVOM/GRM observation
  29. GRB 240819A: KAIT optical upper limit
  30. Fermi trigger No 745873283: Global MASTER-Net observations report
  31. Fermi trigger No 745871958: Global MASTER-Net observations report
  32. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  33. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  34. GRB 240819A: X-ray follow-up observation with EP-FXT
  35. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  36. GRB 240820A: Fermi GBM Final Real-time Localization
  37. GRB 240819A: Swift ToO observations
  38. GRB 240814A: SVOM/GRM observation
  39. GRB 240814C: SVOM/GRM observation
  40. GRB 240815A: SVOM/GRM observation
  41. GRB 240817A: Fermi GBM Final Real-time Localization
  42. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  43. IBAS Alert n.10856: not a GRB
  44. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  45. EP240816b: KAIT optical upper limit
  46. GRB 240814B: GRBAlpha detection
  47. Fermi trigger No 745501396: Global MASTER-Net observations report
  48. Fermi GRB 240814A: Global MASTER-Net observations report
  49. Fermi GRB 240814C: Global MASTER-Net observations report
  50. Fermi trigger No 745306088: Global MASTER-Net observations report
  51. GRB 240814C: Fermi GBM Final Real-time Localization
  52. Fermi GRB 240814B: Global MASTER-Net observations report
  53. GRB 240812B: SVOM/GRM observation
  54. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  55. GRB 240814B: Fermi GBM Final Real-time Localization
  56. GRB 240814A: Fermi GBM Final Real-time Localization
  57. Fermi trigger No 745220784: Global MASTER-Net observations report
  58. Konus-Wind detection of GRB 240811A
  59. Konus-Wind detection of GRB 240810A
  60. Fermi Gamma-ray Burst Monitor trigger 745220784/240813240 is not a GRB
  61. GRB 240809A: Correction to the VLA source position in GCN 37158
  62. GRB 240810A: SVOM/GRM observation
  63. Fermi Gamma-ray Burst Monitor trigger 240812940/745194848 is not a GRB
  64. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  65. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  66. GRB 240809A: ATA radio non-detection
  67. GRB 240812D: Fermi GBM Final Real-time Localization
  68. GRB 240812C: Fermi GBM Final Real-time Localization
  69. GRB 240809A : RAPAS follow-up observations
  70. GRB 240809A: VLA detection
  71. GRB 240809A: ALMA detection
  72. IPN triangulation of GRB 240810A (short)
  73. GRB 240811A: Swift-BAT refined analysis
  74. GRB 240809A: Swift-BAT refined analysis
  75. GRB 240812B: AstroSat CZTI detection of a long burst
  76. GRB 240811A: Bassano Bresciano Observatory upper limit
  77. GRB 240811A: Swift-XRT refined Analysis
  78. Fermi Gamma-ray Burst Monitor trigger 745135620/240812255 is not a GRB
  79. GRB 240811A: Swift/UVOT Upper Limits
  80. EP240801a: Assy-Turgen optical observations
  81. Fermi GRB 240810A: Global MASTER-Net observations report
  82. Fermi Gamma-ray Burst Monitor trigger 240812094/745121685 is not a GRB
  83. GRB 240812A: Fermi GBM Final Real-time Localization
  84. GRB 240811A: LCOGT Optical Upper Limit
  85. GRB 240811A: Enhanced Swift-XRT position
  86. GRB 240811A: Upper limits with Mephisto
  87. Konus-Wind detection of GRB 240809A
  88. Fermi trigger No 745057312: Global MASTER-Net observations report
  89. Swift GRB 240811A: Global MASTER-Net observations report
  90. GRB 240811A: Swift detection of a burst
  91. Fermi Gamma-ray Burst Monitor trigger 745050426/240811269 is not a GRB
  92. GRB 240810A: Fermi GBM Final Real-time Localization
  93. GRB 240809A: REM detection of the optical afterglow
  94. GRB 240809A: Bassano Bresciano Observatory optical observations
  95. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  96. GRB 240809A: Conclusive redshift from VLT
  97. Fermi-LAT gamma-ray observations of IceCube-240808A
  98. GRB 240809A: KAIT optical observations
  99. GRB 240808A: AstroSat CZTI detection
  100. GRB 240809A: GIT afterglow observations

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