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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"

28212 results found.

  1. GRB 251221A: UAFO and Mondy optical upper limit
  2. GRB 251221A: Swift-XRT refined Analysis
  3. EP251221a: Einstein Probe detection of a fast X-ray transient
  4. GRB 251221A: Swift/UVOT Upper Limits
  5. GRB 251221A: Enhanced Swift-XRT position
  6. GRB 251221B: Fermi GBM Final Real-time Localization
  7. EP251220a: EP-FXT follow-up observation
  8. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  9. EP 251220a: GOTO optical counterpart detection
  10. GRB 251221A: COLIBRÍ detection of the optical counterpart
  11. EP 251220a: COLIBRÍ detection of the optical counterpart
  12. GRB 251221A: Swift detection of a burst
  13. GRB 251221A: Fermi GBM Final Real-time Localization
  14. EP251220a: EP detection of a fast X-ray transient
  15. GRB 251220B: Fermi GBM Final Real-time Localization
  16. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  17. GRB 251220A: MAXI/GSC detection
  18. GRB 251215A: Swift-XRT afterglow detection
  19. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  20. GRB 251214B: VIRT Optical Upper Limit
  21. GRB 251217A: Fermi GBM Final Real-time Localization
  22. GRB 251215A: Swift/UVOT Upper LImits
  23. GRB 251215A: Fermi GBM Observation
  24. GRB 251215A: COLIBRÍ optical upper limit
  25. GRB 251216A: Fermi GBM Final Real-time Localization
  26. GRB 251215A: Swift-XRT observations
  27. EP251214a: Optical upper limit with Kinder observations
  28. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  29. GRB 251215A: Glowbug gamma-ray detection
  30. GRB 251214B: VLT/X-shooter observations
  31. GRB 251213A: GRID-10B observation
  32. GRB 251202A: radio detection with the VLA
  33. EP251214b : Einstein Probe detection of a fast X-ray transient
  34. EP251214b : Einstein Probe detection of a fast X-ray transient
  35. GRB 251214B: AbAO optical observations
  36. GRB 251214B: LCO detection of the optical counterpart
  37. GRB 251209A: Insight-HXMT/HE detection
  38. GRB 251215A: Swift ToO observations
  39. EP251214b (EP trigger 01709250023): LCO optical limits
  40. GRID detection of GRB 251213A
  41. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  42. GRB 251214B: Swift-XRT refined Analysis
  43. GRB 251214D: AstroSat CZTI detection of a long burst
  44. GRB 251213A: AstroSat CZTI detection
  45. GRB 251214A: AstroSat CZTI detection
  46. GRB 251213A: GECAM-B detection
  47. GRB 251214B: Swift/UVOT Detection
  48. GRB 251215A: Fermi GBM Final Real-time Localization
  49. GRB 251214B: COLIBRÍ observations of the afterglow
  50. EP251214a: EP-FXT non-detection and upper limit
  51. GRB 251214B: 1.3m DFOT optical detection
  52. GRB 251214B: Enhanced Swift-XRT position
  53. GRB 251214B: Xinglong-2.16m optical observation
  54. GRB 251214C: Fermi GBM Final Localization
  55. GRB 251214B : MASTER optical afterglow detection
  56. GRB 251214B: Swift detection of a burst with an optical counterpart
  57. GRB 251214B: Fermi GBM Final Real-time Localization
  58. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  59. GRB 251214A: Fermi GBM Final Real-time Localization
  60. EP251212a / GRB 251212A: AstroSat CZTI detection
  61. EP251212a: EP-FXT follow-up observation
  62. GRB 251211B: AstroSat CZTI detection
  63. GRB 251209A: NuSTAR detection of prompt emission
  64. EP251212a: Einstein Probe detection of an X-ray transient
  65. GRB 251211B: Fermi GBM Final Real-time Localization
  66. GRB 251211A: Fermi GBM Final Real-time Localization
  67. GRB 251205A: 1.3m DFOT optical upper limit
  68. GRB 251209A: AstroSat CZTI detection
  69. IceCube-251210A - IceCube observation of a high-energy neutrino candidate track-like event
  70. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  71. EP251130a: Mondy and AbAO optical observations
  72. GRB 251208A: AstroSat CZTI detection
  73. Fermi GBM Sub-Threshold Detection of GRB 251205A
  74. GRB 251208A: Glowbug gamma-ray detection
  75. GRB 251208B: COLIBRÍ optical upper limits
  76. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  77. GRB 251208B: Swift-XRT afterglow detection
  78. GRB 251209A: Fermi GBM Final Real-time Localization
  79. GRB 251208D: LCO analysis of the XRT sources
  80. GRB 251208B: GROWTH-India Telescope optical upper limits
  81. GRB 251205A: J-band detection with WINTER
  82. GRB 251208D: Swift-XRT observations
  83. GRB 251208B: Swift ToO observations
  84. GRB 251208B: Fermi-LAT detection
  85. GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
  86. GRB 251208D: SVOM possible detection of a faint burst
  87. GRB 251206A: SVOM detection of a burst through offline search
  88. GRB 251208C: Fermi GBM Final Real-time Localization
  89. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  90. GRB 251208B: Fermi GBM Final Real-time Localization
  91. GRB 251208A: Fermi GBM Final Real-time Localization
  92. EP-WXT trigger 01709249380: confirmation of a stellar flare by BOOTES-5
  93. GRB 251205A: ZTF and ATLAS optical afterglow detections
  94. GRB 251205A: GROWTH-India Telescope optical observations
  95. GRB 251205A: Swift-XRT refined Analysis
  96. GRB 251205A: Swift/UVOT Detection
  97. Konus-Wind detection of GRB 251118A
  98. GRB 251205A: Zeiss-1000 Koshka observatory optical observations
  99. GRB 251205A: GOTO optical afterglow detection
  100. GRB 251205A: NOT optical observations

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