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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"

37185 results found.

  1. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  2. GRB 251222A: NOT optical observations
  3. IPN triangulation of GRB 251220B (short)
  4. GRB 251222A: Swift ToO observations
  5. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  6. GRB 251222A: SVOM/VT optical candidate
  7. GRB 251222A: SVOM detection of a long burst
  8. GRB 251222A: Fermi GBM Final Real-time Localization
  9. GRB 251221A: PRIME near-infrared observation
  10. GRB 251221A: UAFO and Mondy optical upper limit
  11. GRB 251221A: Swift-XRT refined Analysis
  12. GRB 251221A: Swift/UVOT Upper Limits
  13. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  14. GRB 251221A: Enhanced Swift-XRT position
  15. GRB 251221A: Fermi GBM Observation
  16. GRB 251221B: Fermi GBM Final Real-time Localization
  17. GRB 251220B: SVOM/GRM observation of a short burst
  18. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  19. GRB 251221A: COLIBRÍ detection of the optical counterpart
  20. GRB 251221A: Swift detection of a burst
  21. GRB 251221A: Fermi GBM Final Real-time Localization
  22. GRB 251220B: Fermi GBM Final Real-time Localization
  23. GRB 251219A: SVOM/GRM observation of a short burst
  24. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  25. GRB 251220A: MAXI/GSC detection
  26. GRB 251215A: Swift-XRT afterglow detection
  27. GRB 251214B: VIRT Optical Upper Limit
  28. Fermi GRB 251217A: Global MASTER-Net observations report
  29. GRB 251217A: Fermi GBM Final Real-time Localization
  30. GRB 251215A: Swift/UVOT Upper LImits
  31. GRB 251215A: Fermi GBM Observation
  32. Fermi GRB 251216A: Global MASTER-Net observations report
  33. GRB 251202A/EP251202a: Koshka optical upper limit
  34. GRB 251214B: Mondy optical upper limit
  35. GRB 251215A: COLIBRÍ optical upper limit
  36. GRB 251216A: Fermi GBM Final Real-time Localization
  37. EP251214b: KAIT optical upper limit
  38. GRB 251215A: Swift-XRT observations
  39. Fermi GRB 251215A: Global MASTER-Net observations report
  40. EP251214a: Optical upper limit with Kinder observations
  41. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  42. GRB 251215A: Glowbug gamma-ray detection
  43. GRB 251214B: UAFO optical upper limit
  44. GRB 251214B: VLT/X-shooter observations
  45. GRB 251213A: GRID-10B observation
  46. GRB 251214B: Swift-BAT refined analysis
  47. GRB 251202A: radio detection with the VLA
  48. GRB 251214B: AbAO optical observations
  49. GRB 251214B: LCO detection of the optical counterpart
  50. GRB 251209A: GECAM-B observation of a long burst
  51. GRB 251214D: GECAM-B observation of a long burst
  52. GRB 251214B: Fermi GBM Observation
  53. GRB 251209A: Insight-HXMT/HE detection
  54. GRB 251215A: Swift ToO observations
  55. GRID detection of GRB 251213A
  56. GRB 251203B: AbAO optical observations
  57. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  58. GRB 251214B: GECAM-B observation of a long burst
  59. GRB 251214B: Swift-XRT refined Analysis
  60. GRB 251213A: SVOM/GRM observation
  61. EP251214a: KAIT optical upper limit
  62. GRB 251214D: AstroSat CZTI detection of a long burst
  63. GRB 251213A: AstroSat CZTI detection
  64. GRB 251214A: AstroSat CZTI detection
  65. GRB 251213A: GECAM-B detection
  66. GRB 251214B: Swift/UVOT Detection
  67. GRB 251215A: Fermi GBM Final Real-time Localization
  68. GRB 251214B: COLIBRÍ observations of the afterglow
  69. GRB 251214A: GECAM-B observation of a likely long burst
  70. GRB 251214B: 1.3m DFOT optical detection
  71. GRB 251214B: Enhanced Swift-XRT position
  72. GRB 251214B: Xinglong-2.16m optical observation
  73. GRB 251214C: Fermi GBM Final Localization
  74. GRB 251214B : MASTER optical afterglow detection
  75. GRB 251214B: SVOM/C-GFT optical observations
  76. EP251214a: COLIBRÍ optical upper limit
  77. Swift GRB 251214B: Global MASTER-Net observations report
  78. GRB 251214B: Swift detection of a burst with an optical counterpart
  79. GRB 251214B: Fermi GBM Final Real-time Localization
  80. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  81. Fermi GRB 251214A: Global MASTER-Net observations report
  82. GRB 251214A: Fermi GBM Final Real-time Localization
  83. EP251212a: KAIT optical upper limit
  84. EP251212a / GRB 251212A: AstroSat CZTI detection
  85. GRB 251211B: AstroSat CZTI detection
  86. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  87. GRB 251209A: NuSTAR detection of prompt emission
  88. Fermi GRB 251211B: Global MASTER-Net observations report
  89. GRB 251211B: Fermi GBM Final Real-time Localization
  90. GRB 251211A: Fermi GBM Final Real-time Localization
  91. GRB 251209A: Fermi GBM observation
  92. GRB 251205A: 1.3m DFOT optical upper limit
  93. GRB 251209A: AstroSat CZTI detection
  94. EP251124a: Mondy optical upper limit
  95. GRB 251129A/EP251129a: AbAO and Mondy optical observations
  96. EP251130a: Mondy and AbAO optical observations
  97. GRB 251208A: AstroSat CZTI detection
  98. Fermi GBM Sub-Threshold Detection of GRB 251205A
  99. GRB 251208A: Glowbug gamma-ray detection
  100. GRB 251208B: COLIBRÍ optical upper limits

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