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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"

11630 results found.

  1. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  2. GRB 260101A: Fermi GBM Observation
  3. GRB 260101A: GECAM-B detection
  4. GRB 260101A: NOT spectroscopic observations
  5. GRB 260101A: SVOM/GRM observation
  6. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  7. GRB 260101A: LCO detection of the optical counterpart
  8. GRB 260101A: Fermi GBM Final Real-time Localization
  9. Fermi Gamma-ray Burst Monitor trigger 788833547/251231018 is not a GRB
  10. GRB 251231A: Fermi GBM Final Real-time Localization
  11. GRB 251222A: Mondy Optical Observations
  12. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  13. Fermi GRB 251228A: Global MASTER-Net observations report
  14. GRB 251228A: Fermi GBM Final Real-time Localization
  15. GRB 251226A: GECAM-B detection
  16. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  17. Fermi Gamma-ray Burst Monitor trigger 788368008/251225630 is not a GRB
  18. GRB 251222A/EP251222b: Optical detection with Kinder observations
  19. GRB 251222A/EP251222b: FTW optical and NIR observations
  20. GRB 251205A: Kilonova-Catcher optical afterglow detection
  21. GRB 251222A: AbAO optical observations
  22. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  23. GRB 251222A: ZTSH BVRI optical observations
  24. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  25. GRB 251222A: Continued 1.3m DFOT optical observation
  26. GRB 251222A: Fermi GBM Observation
  27. GRB 251222A / EP251222b: GECAM-B observation
  28. Konus-Wind detection of GRB 251222A / EP251222b
  29. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  30. GRB 251222A / EP251222b: GOTO optical counterpart detection
  31. GRB 251222A / EP251222b: LCO optical observations
  32. GRB 251222A: 1.3m DFOT optical detection
  33. GRB251221A: 7DT optical upper limits
  34. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  35. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  36. EP251222b/GRB 251222A: SVOM/GRM observation
  37. GRB 251222A: PRIME near-infrared detection
  38. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  39. GRB 251222A: NOT optical observations
  40. IPN triangulation of GRB 251220B (short)
  41. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  42. GRB 251222A: SVOM detection of a long burst
  43. GRB 251222A: Fermi GBM Final Real-time Localization
  44. GRB 251221A: PRIME near-infrared observation
  45. GRB 251221A: UAFO and Mondy optical upper limit
  46. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  47. GRB 251221A: Fermi GBM Observation
  48. GRB 251221B: Fermi GBM Final Real-time Localization
  49. GRB 251220B: SVOM/GRM observation of a short burst
  50. GRB 251221A: COLIBRÍ detection of the optical counterpart
  51. GRB 251221A: Fermi GBM Final Real-time Localization
  52. GRB 251220B: Fermi GBM Final Real-time Localization
  53. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  54. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  55. GRB 251214B: VIRT Optical Upper Limit
  56. Fermi trigger No 787736968: Global MASTER-Net observations report
  57. Fermi GRB 251217A: Global MASTER-Net observations report
  58. GRB 251217A: Fermi GBM Final Real-time Localization
  59. GRB 251215A: Swift/UVOT Upper LImits
  60. GRB 251215A: Fermi GBM Observation
  61. Fermi GRB 251216A: Global MASTER-Net observations report
  62. GRB 251202A/EP251202a: Koshka optical upper limit
  63. GRB 251214B: Mondy optical upper limit
  64. GRB 251215A: COLIBRÍ optical upper limit
  65. GRB 251216A: Fermi GBM Final Real-time Localization
  66. Fermi GRB 251215A: Global MASTER-Net observations report
  67. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  68. GRB 251215A: Glowbug gamma-ray detection
  69. GRB 251214B: UAFO optical upper limit
  70. GRB 251214B: VLT/X-shooter observations
  71. GRB 251202A: radio detection with the VLA
  72. GRB 251214B: AbAO optical observations
  73. GRB 251214B: LCO detection of the optical counterpart
  74. GRB 251209A: GECAM-B observation of a long burst
  75. GRB 251214B: Fermi GBM Observation
  76. GRB 251209A: Insight-HXMT/HE detection
  77. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  78. GRB 251214B: GECAM-B observation of a long burst
  79. GRB 251214A: AstroSat CZTI detection
  80. GRB 251213A: GECAM-B detection
  81. GRB 251215A: Fermi GBM Final Real-time Localization
  82. GRB 251214B: COLIBRÍ observations of the afterglow
  83. GRB 251214A: GECAM-B observation of a likely long burst
  84. GRB 251214B: 1.3m DFOT optical detection
  85. GRB 251214C: Fermi GBM Final Localization
  86. GRB 251214B : MASTER optical afterglow detection
  87. Fermi trigger No 787396657: Global MASTER-Net observations report
  88. GRB 251214B: SVOM/C-GFT optical observations
  89. EP251214a: COLIBRÍ optical upper limit
  90. GRB 251214B: Fermi GBM Final Real-time Localization
  91. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  92. Fermi GRB 251214A: Global MASTER-Net observations report
  93. GRB 251214A: Fermi GBM Final Real-time Localization
  94. GRB 251211B: AstroSat CZTI detection
  95. GRB 251209A: NuSTAR detection of prompt emission
  96. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  97. Fermi GRB 251211B: Global MASTER-Net observations report
  98. GRB 251211B: Fermi GBM Final Real-time Localization
  99. GRB 251211A: Fermi GBM Final Real-time Localization
  100. GRB 251209A: Fermi GBM observation

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