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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"

12385 results found.

  1. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  2. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  3. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  4. GRB 251214B: VIRT Optical Upper Limit
  5. Fermi trigger No 787736968: Global MASTER-Net observations report
  6. Fermi GRB 251217A: Global MASTER-Net observations report
  7. GRB 251217A: Fermi GBM Final Real-time Localization
  8. GRB 251215A: Swift/UVOT Upper LImits
  9. GRB 251215A: Fermi GBM Observation
  10. Fermi GRB 251216A: Global MASTER-Net observations report
  11. GRB 251202A/EP251202a: Koshka optical upper limit
  12. GRB 251214B: Mondy optical upper limit
  13. GRB 251215A: COLIBRÍ optical upper limit
  14. GRB 251216A: Fermi GBM Final Real-time Localization
  15. Fermi GRB 251215A: Global MASTER-Net observations report
  16. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  17. GRB 251215A: Glowbug gamma-ray detection
  18. GRB 251214B: UAFO optical upper limit
  19. GRB 251214B: VLT/X-shooter observations
  20. GRB 251202A: radio detection with the VLA
  21. GRB 251214B: AbAO optical observations
  22. GRB 251214B: LCO detection of the optical counterpart
  23. GRB 251209A: GECAM-B observation of a long burst
  24. GRB 251214B: Fermi GBM Observation
  25. GRB 251209A: Insight-HXMT/HE detection
  26. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  27. GRB 251214B: GECAM-B observation of a long burst
  28. GRB 251214A: AstroSat CZTI detection
  29. GRB 251213A: GECAM-B detection
  30. GRB 251215A: Fermi GBM Final Real-time Localization
  31. GRB 251214B: COLIBRÍ observations of the afterglow
  32. GRB 251214A: GECAM-B observation of a likely long burst
  33. GRB 251214B: 1.3m DFOT optical detection
  34. GRB 251214C: Fermi GBM Final Localization
  35. GRB 251214B : MASTER optical afterglow detection
  36. Fermi trigger No 787396657: Global MASTER-Net observations report
  37. GRB 251214B: SVOM/C-GFT optical observations
  38. EP251214a: COLIBRÍ optical upper limit
  39. GRB 251214B: Fermi GBM Final Real-time Localization
  40. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  41. Fermi GRB 251214A: Global MASTER-Net observations report
  42. GRB 251214A: Fermi GBM Final Real-time Localization
  43. GRB 251211B: AstroSat CZTI detection
  44. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  45. GRB 251209A: NuSTAR detection of prompt emission
  46. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  47. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  48. Fermi GRB 251211B: Global MASTER-Net observations report
  49. GRB 251211B: Fermi GBM Final Real-time Localization
  50. GRB 251211A: Fermi GBM Final Real-time Localization
  51. GRB 251209A: Fermi GBM observation
  52. GRB 251209A: AstroSat CZTI detection
  53. IceCube-251210A - IceCube observation of a high-energy neutrino candidate track-like event
  54. GRB 251208A: AstroSat CZTI detection
  55. Fermi GBM Sub-Threshold Detection of GRB 251205A
  56. GRB 251208A: Glowbug gamma-ray detection
  57. GRB 251208B: COLIBRÍ optical upper limits
  58. GRB 251208C: GECAM-B observation of a short burst
  59. GRB 251208A: GECAM-B observation of a short burst
  60. Fermi GRB 251209A: Global MASTER-Net observations report
  61. Fermi GRB 251208C: Global MASTER-Net observations report
  62. GRB 251208B: Swift-XRT afterglow detection
  63. GRB 251209A: Fermi GBM Final Real-time Localization
  64. GRB 251208B: Fermi GBM Observation
  65. GRB 251208B: GROWTH-India Telescope optical upper limits
  66. GRB 251208A: SVOM/GRM observation of a short burst
  67. GRB 251208C: SVOM/GRM observation of a short burst
  68. GRB 251208B: Swift ToO observations
  69. GRB 251208B: Fermi-LAT detection
  70. GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
  71. GRB 251208C: Fermi GBM Final Real-time Localization
  72. GRB 251208B: Fermi GBM Final Real-time Localization
  73. GRB 251208A: Fermi GBM Final Real-time Localization
  74. Konus-Wind detection of GRB 251118A
  75. GRB 251126B: Fermi GBM Final Localization
  76. GRB 251203A: Insight-HXMT/HE detection
  77. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  78. GRB 251202A: SVOM/GRM observation
  79. GRB 251203A: GECAM-B observation of a burst
  80. GRB 251203A: SVOM/GRM observation
  81. GRB 251201B: SALT spectroscopic redshift z = 1.599
  82. GRB 251203A: AstroSat CZTI detection
  83. Fermi Gamma-ray Burst Monitor trigger 786496343/251203967 is not a GRB
  84. GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
  85. GRB 251201B: Insight-HXMT/HE detection
  86. EP251202a / GRB 251202A: Insight-HXMT/HE detection
  87. GRB 251203A: Fermi GBM Final Real-time Localization
  88. EP251202a / GRB251202A: AstroSat CZTI detection
  89. GRB 251202A / EP251202a: SVOM/VT optical observation
  90. GRB 251201B: Fermi GBM Observation
  91. EP251202a/GRB 251202A: KAIT optical observations
  92. Fermi GRB 251202B: Global MASTER-Net observations report
  93. GRB 251202B: Fermi GBM Final Real-time Localization
  94. GRB 251202A: Fermi GBM Observation
  95. GRB 251201B: Kilonova-Catcher optical afterglow detection
  96. GRB 251130B: Glowbug gamma-ray detection
  97. GRB 251201B: GECAM-B observation of a long burst
  98. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  99. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  100. GRB 251202A: GOTO optical afterglow detection

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