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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"
  1. Fermi trigger No 745873283: Global MASTER-Net observations report
  2. Fermi trigger No 745871958: Global MASTER-Net observations report
  3. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  4. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  5. GRB 240819A: X-ray follow-up observation with EP-FXT
  6. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  7. GRB 240820A: Fermi GBM Final Real-time Localization
  8. GRB 240819A: Swift ToO observations
  9. GRB 240814A: SVOM/GRM observation
  10. EP240816b: Liverpool Telescope optical follow-up observations
  11. GRB 240814C: SVOM/GRM observation
  12. EP240816a: BOOTES-6/DPRT optical upper limit
  13. GRB 240815A: SVOM/GRM observation
  14. GRB 240817A: Fermi GBM Final Real-time Localization
  15. Integral GRB240816.79: Global MASTER-Net observations report
  16. IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
  17. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  18. IBAS Alert n.10856: not a GRB
  19. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  20. EP240816b: KAIT optical upper limit
  21. GRB 240814B: GRBAlpha detection
  22. Fermi trigger No 745501396: Global MASTER-Net observations report
  23. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  24. EP EP240816b: Global MASTER-Net observations report
  25. EP240816b: TRT optical upper limit
  26. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  27. Fermi GRB 240814A: Global MASTER-Net observations report
  28. Fermi GRB 240814C: Global MASTER-Net observations report
  29. Fermi trigger No 745306088: Global MASTER-Net observations report
  30. GRB 240814C: Fermi GBM Final Real-time Localization
  31. Fermi GRB 240814B: Global MASTER-Net observations report
  32. GRB 240812B: SVOM/GRM observation
  33. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  34. GRB 240814B: Fermi GBM Final Real-time Localization
  35. GRB 240814A: Fermi GBM Final Real-time Localization
  36. LIGO/Virgo/KAGRA S240813d: Updated Sky localization
  37. Fermi trigger No 745220784: Global MASTER-Net observations report
  38. Konus-Wind detection of GRB 240811A
  39. Konus-Wind detection of GRB 240810A
  40. Fermi Gamma-ray Burst Monitor trigger 745220784/240813240 is not a GRB
  41. LIGO/Virgo/KAGRA S240813d: Identification of a GW compact binary merger candidate
  42. LIGO/Virgo/KAGRA S240813c: Updated Sky localization
  43. LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
  44. GRB 240809A: Correction to the VLA source position in GCN 37158
  45. GRB 240810A: SVOM/GRM observation
  46. Fermi Gamma-ray Burst Monitor trigger 240812940/745194848 is not a GRB
  47. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  48. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  49. GRB 240809A: ATA radio non-detection
  50. GRB 240812D: Fermi GBM Final Real-time Localization
  51. GRB 240812C: Fermi GBM Final Real-time Localization
  52. GRB 240809A : RAPAS follow-up observations
  53. GRB 240809A: VLA detection
  54. GRB 240809A: ALMA detection
  55. IPN triangulation of GRB 240810A (short)
  56. GRB 240811A: Swift-BAT refined analysis
  57. GRB 240809A: Swift-BAT refined analysis
  58. EP240807a: PRIME H-band upper limits
  59. GRB 240812B: AstroSat CZTI detection of a long burst
  60. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  61. GRB 240811A: Bassano Bresciano Observatory upper limit
  62. GRB 240811A: Swift-XRT refined Analysis
  63. Fermi Gamma-ray Burst Monitor trigger 745135620/240812255 is not a GRB
  64. GRB 240811A: Swift/UVOT Upper Limits
  65. EP240801a: Assy-Turgen optical observations
  66. Fermi GRB 240810A: Global MASTER-Net observations report
  67. Fermi Gamma-ray Burst Monitor trigger 240812094/745121685 is not a GRB
  68. GRB 240812A: Fermi GBM Final Real-time Localization
  69. GRB 240811A: LCOGT Optical Upper Limit
  70. GRB 240811A: Enhanced Swift-XRT position
  71. GRB 240811A: Upper limits with Mephisto
  72. Konus-Wind detection of GRB 240809A
  73. Fermi trigger No 745057312: Global MASTER-Net observations report
  74. Swift GRB 240811A: Global MASTER-Net observations report
  75. GRB 240811A: Swift detection of a burst
  76. Fermi Gamma-ray Burst Monitor trigger 745050426/240811269 is not a GRB
  77. GRB240809A: Liverpool Telescope optical follow-up observations
  78. GRB 240810A: Fermi GBM Final Real-time Localization
  79. GRB 240809A: REM detection of the optical afterglow
  80. GRB 240809A: Bassano Bresciano Observatory optical observations
  81. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  82. GRB 240809A: Conclusive redshift from VLT
  83. Fermi-LAT gamma-ray observations of IceCube-240808A
  84. GRB 240809A: KAIT optical observations
  85. GRB 240808A: AstroSat CZTI detection
  86. GRB 240809A: GIT afterglow observations
  87. GRB 240809B: MAXI/GSC detection
  88. GRB 240809A: Swift/UVOT Detection
  89. GRB 240809A: Tentative redshift from NOT
  90. GRB 240809A: Swift-XRT refined Analysis
  91. IPN triangulation of GRB 240807A / EP 240807a
  92. LIGO/Virgo/KAGRA S240807h: Updated Sky localization and EM Bright Classification
  93. X-ray Transient EP240807a: PRIME near-infrared upper limits
  94. Swift GRB 240809A: Global MASTER-Net observations report
  95. GRB 240809A: JinShan optical observations
  96. GRB 240809A: Enhanced Swift-XRT position
  97. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  98. GRB 240809A: SVOM/GRM observation
  99. GRB 240808A: SVOM/GRM observation
  100. GRB 240807A: SVOM/GRM observation

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