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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"

36790 results found.

  1. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  2. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  3. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  4. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  5. Fermi GRB 240702A: Global MASTER-Net observations report
  6. GRB 240702A: Fermi GBM Final Real-time Localization
  7. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  8. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  9. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  10. Fermi trigger No 741448122: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  12. Fermi trigger No 741356809: Global MASTER-Net observations report
  13. Fermi GRB 240629A: Global MASTER-Net observations report
  14. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  15. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  16. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  17. GRB 240629A: Fermi GBM Final Real-time Localization
  18. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  19. Fermi trigger No 741296200: Global MASTER-Net observations report
  20. Fermi trigger No 741251380: Global MASTER-Net observations report
  21. IPN triangulation of GRB 240619C
  22. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  23. GRB 240627A: NuSTAR Detection of the long GRB
  24. GRB 240615A: SAI CMO J- band observations
  25. GRB 240627A: AstroSat CZTI detection
  26. Fermi trigger No 741211696: Global MASTER-Net observations report
  27. EP240626a: Montarrenti Observatory optical upper limit
  28. EP240626a: KAIT optical upper limit
  29. GRB 240624A: Swift-BAT refined analysis
  30. Konus-Wind detection of GRB 240619A
  31. Fermi GRB 240625B: Global MASTER-Net observations report
  32. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  33. GRB 240625B: Fermi GBM Final Real-time Localization
  34. GRB 240625A: Fermi GBM Observation
  35. GRB 240624B: GRBAlpha detection
  36. GRB 240625A: Fermi GBM Final Real-time Localization
  37. GRB240624A: Fermi GBM Observation
  38. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  39. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  40. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  41. Swift GRB 240624A: Global MASTER-Net observations report
  42. GRB240615A: Gemini-North observations of the BAT and XRT positions
  43. Fermi GRB 240624A: Global MASTER-Net observations report
  44. GRB 240624B: Fermi GBM Final Real-time Localization
  45. Fermi trigger No 740949590: Global MASTER-Net observations report
  46. GRB240615A: Gemini-North observations of the BAT and XRT positions
  47. GRB 240624A: Fermi GBM Final Real-time Localization
  48. GRB 240619A: detection of a radio counterpart with AMI-LA
  49. GRB 240624A: Swift detection of a burst
  50. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  51. GRB 240619A: J-band detection with WINTER
  52. Fermi trigger No 740744838: Global MASTER-Net observations report
  53. EP240618a: NOT optical counterpart candidate
  54. GRB 240529A: JinShan optical observations
  55. IPN triangulation of GRB 240615A (short)
  56. X-ray transient EP240618a: Fermi/GBM non-detection
  57. GRB 240619A: GRBAlpha detection
  58. EP240617a: tentative Swift/XRT detection of the afterglow
  59. GRB 240619A: Swift-XRT probable afterglow detection
  60. GRB 240619A: Swift ToO observations
  61. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  62. GRB 240619C: NuSTAR automated detection of the GRB
  63. GRB 240619A: Fermi GBM Observation
  64. Fermi GBM Sub-Threshold Detection of GRB 240619C
  65. GRB 240619A: GOTO candidate optical afterglow
  66. EP240618a: Abastumani optical observationsEP240618a
  67. GRB 240615A: NOT optical observations
  68. GRB 240619C: AstroSat CZTI detection
  69. Fermi trigger No 740474239: Global MASTER-Net observations report
  70. Fermi GRB 240619A: Global MASTER-Net observations report
  71. GRB 240615A: possible transient detection from Wendelstein observations
  72. Fermi Gamma-ray Burst Monitor trigger 740474239/240619304 is not a GRB
  73. GRB 240619B: Fermi GBM Final Real-time Localization
  74. Fermi trigger No 740430582: Global MASTER-Net observations report
  75. GRB240615A: 1.3m DFOT optical upper limit
  76. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  77. GRB 240619A: Fermi GBM Final Real-time Localization
  78. EP240617a: BOOTES-6/DPRT optical upper limit
  79. EP240617a is likely a GRB event
  80. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  81. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  82. GRB 240615A: J-band upper limits from WINTER
  83. GRB 240615A: Fermi GBM Observation
  84. GRB 240615A: Swift-XRT observations
  85. GRB 240615A: GECAM detection
  86. GRB 240615A: FLWO-1.2m optical upper limits
  87. Fermi trigger No 740221779: Global MASTER-Net observations report
  88. Fermi GRB 240616A: Global MASTER-Net observations report
  89. Konus-Wind detection of GRB 240615A (short/hard)
  90. GRB 240615A: GOTO optical upper limits
  91. Fermi trigger No 740166710: Global MASTER-Net observations report
  92. GRB 240616A: Fermi GBM Final Real-time Localization
  93. GRB 240615A: Swift ToO observations
  94. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  95. GRB 240615A: Fermi GBM Final Real-time Localization
  96. GRB 240603A: VZLUSAT-2 detection
  97. GRB 240612A: GRBAlpha detection
  98. GRB 240613A: Fermi GBM Final Real-time Localization
  99. Fermi GRB 240612B: Global MASTER-Net observations report
  100. Fermi GRB 240612A: Global MASTER-Net observations report

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