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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"

36078 results found.

  1. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  2. GRB 251221A: Enhanced Swift-XRT position
  3. GRB 251221A: Fermi GBM Observation
  4. GRB 251221B: Fermi GBM Final Real-time Localization
  5. GRB 251220B: SVOM/GRM observation of a short burst
  6. GRB 251221A: COLIBRÍ detection of the optical counterpart
  7. GRB 251221A: Swift detection of a burst
  8. GRB 251221A: Fermi GBM Final Real-time Localization
  9. GRB 251220B: Fermi GBM Final Real-time Localization
  10. GRB 251219A: SVOM/GRM observation of a short burst
  11. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  12. GRB 251220A: MAXI/GSC detection
  13. GRB 251215A: Swift-XRT afterglow detection
  14. GRB 251214B: VIRT Optical Upper Limit
  15. Fermi GRB 251217A: Global MASTER-Net observations report
  16. GRB 251217A: Fermi GBM Final Real-time Localization
  17. GRB 251215A: Swift/UVOT Upper LImits
  18. GRB 251215A: Fermi GBM Observation
  19. Fermi GRB 251216A: Global MASTER-Net observations report
  20. GRB 251202A/EP251202a: Koshka optical upper limit
  21. GRB 251214B: Mondy optical upper limit
  22. GRB 251215A: COLIBRÍ optical upper limit
  23. GRB 251216A: Fermi GBM Final Real-time Localization
  24. EP251214b: KAIT optical upper limit
  25. GRB 251215A: Swift-XRT observations
  26. Fermi GRB 251215A: Global MASTER-Net observations report
  27. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  28. GRB 251215A: Glowbug gamma-ray detection
  29. GRB 251214B: UAFO optical upper limit
  30. GRB 251214B: VLT/X-shooter observations
  31. GRB 251213A: GRID-10B observation
  32. GRB 251214B: Swift-BAT refined analysis
  33. GRB 251202A: radio detection with the VLA
  34. GRB 251214B: AbAO optical observations
  35. GRB 251214B: LCO detection of the optical counterpart
  36. GRB 251209A: GECAM-B observation of a long burst
  37. GRB 251214D: GECAM-B observation of a long burst
  38. GRB 251214B: Fermi GBM Observation
  39. GRB 251209A: Insight-HXMT/HE detection
  40. GRB 251215A: Swift ToO observations
  41. GRID detection of GRB 251213A
  42. GRB 251203B: AbAO optical observations
  43. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  44. GRB 251214B: GECAM-B observation of a long burst
  45. GRB 251214B: Swift-XRT refined Analysis
  46. GRB 251213A: SVOM/GRM observation
  47. EP251214a: KAIT optical upper limit
  48. GRB 251214D: AstroSat CZTI detection of a long burst
  49. GRB 251213A: AstroSat CZTI detection
  50. GRB 251214A: AstroSat CZTI detection
  51. GRB 251213A: GECAM-B detection
  52. GRB 251214B: Swift/UVOT Detection
  53. GRB 251215A: Fermi GBM Final Real-time Localization
  54. GRB 251214B: COLIBRÍ observations of the afterglow
  55. GRB 251214A: GECAM-B observation of a likely long burst
  56. GRB 251214B: 1.3m DFOT optical detection
  57. GRB 251214B: Enhanced Swift-XRT position
  58. GRB 251214B: Xinglong-2.16m optical observation
  59. GRB 251214C: Fermi GBM Final Localization
  60. GRB 251214B : MASTER optical afterglow detection
  61. GRB 251214B: SVOM/C-GFT optical observations
  62. EP251214a: COLIBRÍ optical upper limit
  63. Swift GRB 251214B: Global MASTER-Net observations report
  64. GRB 251214B: Swift detection of a burst with an optical counterpart
  65. GRB 251214B: Fermi GBM Final Real-time Localization
  66. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  67. Fermi GRB 251214A: Global MASTER-Net observations report
  68. GRB 251214A: Fermi GBM Final Real-time Localization
  69. EP251212a: KAIT optical upper limit
  70. EP251212a / GRB 251212A: AstroSat CZTI detection
  71. GRB 251211B: AstroSat CZTI detection
  72. GRB 251209A: NuSTAR detection of prompt emission
  73. Fermi GRB 251211B: Global MASTER-Net observations report
  74. GRB 251211B: Fermi GBM Final Real-time Localization
  75. GRB 251211A: Fermi GBM Final Real-time Localization
  76. GRB 251209A: Fermi GBM observation
  77. GRB 251205A: 1.3m DFOT optical upper limit
  78. GRB 251209A: AstroSat CZTI detection
  79. EP251124a: Mondy optical upper limit
  80. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  81. EP251130a: Mondy and AbAO optical observations
  82. GRB 251208A: AstroSat CZTI detection
  83. Fermi GBM Sub-Threshold Detection of GRB 251205A
  84. GRB 251208A: Glowbug gamma-ray detection
  85. GRB 251208B: COLIBRÍ optical upper limits
  86. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  87. GRB 251208C: GECAM-B observation of a short burst
  88. GRB 251208A: GECAM-B observation of a short burst
  89. Fermi GRB 251209A: Global MASTER-Net observations report
  90. Fermi GRB 251208C: Global MASTER-Net observations report
  91. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  92. GRB 251208B: Swift-XRT afterglow detection
  93. GRB 251208D: LAST optical upper limit
  94. GRB 251209A: Fermi GBM Final Real-time Localization
  95. GRB 251208D: LCO analysis of the XRT sources
  96. GRB 251208B: Fermi GBM Observation
  97. GRB 251208B: GROWTH-India Telescope optical upper limits
  98. GRB 251205A: J-band detection with WINTER
  99. GRB 251208D: Swift-XRT observations
  100. GRB 251208A: SVOM/GRM observation of a short burst

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