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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"

39220 results found.

  1. GRB 240821A: Colibri Optical Upper Limit
  2. EP240820a: PRIME J-band Observations
  3. GRB 240821A: Swift-XRT observations
  4. GRB 240822A: AstroSat CZTI detection of a short burst
  5. GRB 240821A: REM optical/NIR upper limits
  6. GRB 240821A: LCO optical observations
  7. GRB 240821A: JinShan optical upper limits
  8. GRB 240809A: Mondy and AbAO Optical Observations
  9. GRB 240821A: SVOM/VT follow-up and optical upper limit
  10. GRB 240821A: GMG Optical Upper Limit
  11. Fermi GRB 240821A: Global MASTER-Net observations report
  12. GRB 240821A: Fermi GBM Observation
  13. Fermi trigger No 745964969: Global MASTER-Net observations report
  14. Fermi trigger No 745925274: Global MASTER-Net observations report
  15. GRB 240821A: Swift ToO observations
  16. Fermi trigger No 746019401: Global MASTER-Net observations report
  17. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  18. Fermi trigger No 745935375: Global MASTER-Net observations report
  19. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  20. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  21. Fermi GRB 240821B: Global MASTER-Net observations report
  22. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  23. GRB 240821A: SVOM/GRM observation
  24. GRB 240821A: SVOM/GRM observation
  25. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  26. GRB 240821B: Fermi GBM Final Localization
  27. Fermi trigger No 745866488: Global MASTER-Net observations report
  28. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  29. GRB 240821A: BALROG localization (Fermi Trigger 745958167 / GRB 240821775)
  30. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  31. GRB 240821A: Fermi GBM Final Real-time Localization
  32. GRB 240819A: Swift-XRT observations
  33. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  34. GRB 240820B: SVOM/GRM observation
  35. EP240820a: TRT optical upper limit
  36. GRB 240819A: KAIT optical upper limit
  37. EP240816a: PRIME upper limits
  38. Fermi trigger No 745873283: Global MASTER-Net observations report
  39. Fermi trigger No 745871958: Global MASTER-Net observations report
  40. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  41. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  42. GRB 240819A: X-ray follow-up observation with EP-FXT
  43. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  44. GRB 240820A: Fermi GBM Final Real-time Localization
  45. GRB 240819A: Swift ToO observations
  46. GRB 240814A: SVOM/GRM observation
  47. GRB 240814C: SVOM/GRM observation
  48. GRB 240815A: SVOM/GRM observation
  49. GRB 240817A: Fermi GBM Final Real-time Localization
  50. Integral GRB240816.79: Global MASTER-Net observations report
  51. IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
  52. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  53. IBAS Alert n.10856: not a GRB
  54. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  55. EP240816b: KAIT optical upper limit
  56. GRB 240814B: GRBAlpha detection
  57. Fermi trigger No 745501396: Global MASTER-Net observations report
  58. EP EP240816b: Global MASTER-Net observations report
  59. EP240816b: TRT optical upper limit
  60. Fermi GRB 240814A: Global MASTER-Net observations report
  61. Fermi GRB 240814C: Global MASTER-Net observations report
  62. Fermi trigger No 745306088: Global MASTER-Net observations report
  63. GRB 240814C: Fermi GBM Final Real-time Localization
  64. Fermi GRB 240814B: Global MASTER-Net observations report
  65. GRB 240812B: SVOM/GRM observation
  66. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  67. GRB 240814B: Fermi GBM Final Real-time Localization
  68. GRB 240814A: Fermi GBM Final Real-time Localization
  69. Fermi trigger No 745220784: Global MASTER-Net observations report
  70. Konus-Wind detection of GRB 240811A
  71. Konus-Wind detection of GRB 240810A
  72. Fermi Gamma-ray Burst Monitor trigger 745220784/240813240 is not a GRB
  73. GRB 240809A: Correction to the VLA source position in GCN 37158
  74. GRB 240810A: SVOM/GRM observation
  75. Fermi Gamma-ray Burst Monitor trigger 240812940/745194848 is not a GRB
  76. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  77. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  78. GRB 240809A: ATA radio non-detection
  79. GRB 240812D: Fermi GBM Final Real-time Localization
  80. GRB 240812C: Fermi GBM Final Real-time Localization
  81. GRB 240809A : RAPAS follow-up observations
  82. GRB 240809A: VLA detection
  83. GRB 240809A: ALMA detection
  84. IPN triangulation of GRB 240810A (short)
  85. GRB 240811A: Swift-BAT refined analysis
  86. GRB 240809A: Swift-BAT refined analysis
  87. EP240807a: PRIME H-band upper limits
  88. GRB 240812B: AstroSat CZTI detection of a long burst
  89. GRB 240811A: Bassano Bresciano Observatory upper limit
  90. GRB 240811A: Swift-XRT refined Analysis
  91. Fermi Gamma-ray Burst Monitor trigger 745135620/240812255 is not a GRB
  92. GRB 240811A: Swift/UVOT Upper Limits
  93. EP240801a: Assy-Turgen optical observations
  94. Fermi GRB 240810A: Global MASTER-Net observations report
  95. Fermi Gamma-ray Burst Monitor trigger 240812094/745121685 is not a GRB
  96. GRB 240812A: Fermi GBM Final Real-time Localization
  97. GRB 240811A: LCOGT Optical Upper Limit
  98. GRB 240811A: Enhanced Swift-XRT position
  99. GRB 240811A: Upper limits with Mephisto
  100. Konus-Wind detection of GRB 240809A

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