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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"

35423 results found.

  1. GRB 240824B: Swift/BAT arcminute localization of a burst
  2. GRB 240824B: Swift ToO observations
  3. Fermi GRB 240824C: Global MASTER-Net observations report
  4. GRB 240824C: Fermi GBM Final Localization
  5. GRB 240824A: Swift/UVOT Upper Limits
  6. GRB 240821A: Swift/UVOT observations of the XRT sources.
  7. GRB 240824B: MAXI/GSC detection
  8. GRB 240824B: Fermi GBM Final Real-time Localization
  9. GRB 240824A: Retraction of GCN 37255
  10. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  11. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  12. GRB 240824A: KAIT optical upper limit
  13. GRB 240824A: Skynet Optical Afterglow Discovery
  14. GRB 240824A: Swift detection of a burst
  15. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  16. GRB 240821A: Colibri Optical Upper Limit
  17. GRB 240821A: Swift-XRT observations
  18. GRB 240822A: AstroSat CZTI detection of a short burst
  19. GRB 240821A: REM optical/NIR upper limits
  20. GRB 240821A: LCO optical observations
  21. GRB 240821A: JinShan optical upper limits
  22. GRB 240809A: Mondy and AbAO Optical Observations
  23. GRB 240821A: SVOM/VT follow-up and optical upper limit
  24. GRB 240821A: GMG Optical Upper Limit
  25. Fermi GRB 240821A: Global MASTER-Net observations report
  26. GRB 240821A: Fermi GBM Observation
  27. GRB 240821A: Swift ToO observations
  28. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  29. GRB240821A: EIRSAT-1 GMOD Detection
  30. GRB240821B: First GRB Detected by EIRSAT-1 GMOD
  31. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  32. Fermi GRB 240821B: Global MASTER-Net observations report
  33. EP240801a: Keck/LRIS spectroscopic redshift confirmation
  34. GRB 240821A: SVOM/GRM observation
  35. GRB 240821A: SVOM/GRM observation
  36. GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
  37. GRB 240821B: Fermi GBM Final Localization
  38. GRB 240821A: BALROG localization (Fermi Trigger 745958167 / GRB 240821775)
  39. GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
  40. GRB 240821A: Fermi GBM Final Real-time Localization
  41. GRB 240819A: Swift-XRT observations
  42. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  43. GRB 240820B: SVOM/GRM observation
  44. GRB 240819A: KAIT optical upper limit
  45. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  46. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  47. GRB 240819A: X-ray follow-up observation with EP-FXT
  48. Fermi Gamma-ray Burst Monitor trigger 745811685 / 240820080 is not a GRB
  49. GRB 240820A: Fermi GBM Final Real-time Localization
  50. GRB 240819A: Swift ToO observations
  51. GRB 240814A: SVOM/GRM observation
  52. GRB 240814C: SVOM/GRM observation
  53. GRB 240815A: SVOM/GRM observation
  54. GRB 240817A: Fermi GBM Final Real-time Localization
  55. GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  56. IBAS Alert n.10856: not a GRB
  57. GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
  58. EP240816b: KAIT optical upper limit
  59. GRB 240814B: GRBAlpha detection
  60. Fermi GRB 240814A: Global MASTER-Net observations report
  61. Fermi GRB 240814C: Global MASTER-Net observations report
  62. GRB 240814C: Fermi GBM Final Real-time Localization
  63. Fermi GRB 240814B: Global MASTER-Net observations report
  64. GRB 240812B: SVOM/GRM observation
  65. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  66. GRB 240814B: Fermi GBM Final Real-time Localization
  67. GRB 240814A: Fermi GBM Final Real-time Localization
  68. Konus-Wind detection of GRB 240811A
  69. Konus-Wind detection of GRB 240810A
  70. Fermi Gamma-ray Burst Monitor trigger 745220784/240813240 is not a GRB
  71. GRB 240809A: Correction to the VLA source position in GCN 37158
  72. GRB 240810A: SVOM/GRM observation
  73. Fermi Gamma-ray Burst Monitor trigger 240812940/745194848 is not a GRB
  74. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  75. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  76. GRB 240809A: ATA radio non-detection
  77. GRB 240812D: Fermi GBM Final Real-time Localization
  78. GRB 240812C: Fermi GBM Final Real-time Localization
  79. GRB 240809A : RAPAS follow-up observations
  80. GRB 240809A: VLA detection
  81. GRB 240809A: ALMA detection
  82. IPN triangulation of GRB 240810A (short)
  83. GRB 240811A: Swift-BAT refined analysis
  84. GRB 240809A: Swift-BAT refined analysis
  85. GRB 240812B: AstroSat CZTI detection of a long burst
  86. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  87. GRB 240811A: Bassano Bresciano Observatory upper limit
  88. GRB 240811A: Swift-XRT refined Analysis
  89. Fermi Gamma-ray Burst Monitor trigger 745135620/240812255 is not a GRB
  90. GRB 240811A: Swift/UVOT Upper Limits
  91. EP240801a: Assy-Turgen optical observations
  92. Fermi GRB 240810A: Global MASTER-Net observations report
  93. Fermi Gamma-ray Burst Monitor trigger 240812094/745121685 is not a GRB
  94. GRB 240812A: Fermi GBM Final Real-time Localization
  95. GRB 240811A: LCOGT Optical Upper Limit
  96. GRB 240811A: Enhanced Swift-XRT position
  97. GRB 240811A: Upper limits with Mephisto
  98. Konus-Wind detection of GRB 240809A
  99. Swift GRB 240811A: Global MASTER-Net observations report
  100. GRB 240811A: Swift detection of a burst

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