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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"

11617 results found.

  1. GRB 251028A: GECAM-B detection
  2. GRB 251028A: SVOM/GRM observation
  3. GRB 251028A: Fermi GBM Observation
  4. GRB 251022A: Swift-XRT confirmation of fading
  5. GRB 251026B: LBT near-infrared observations
  6. GRB 250926B: VZLUSAT-2 detection
  7. GRB 250926A: VZLUSAT-2 detection
  8. GRB 251026B: Fermi GBM Observation
  9. GRB 251028B: Fermi/GBM observation
  10. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  11. GRB 251028B: Glowbug gamma-ray detection
  12. GRB 251028A: Glowbug gamma-ray detection
  13. GRB 251028B: CALET Gamma-Ray Burst Monitor detection
  14. Fermi GRB 251028B: Global MASTER-Net observations report
  15. GRB 251028B: Fermi GBM Final Localization Correction
  16. GRB251026B: PRIME H-band upper limit
  17. GRB 251028A: BALROG localization (Fermi Trigger 783314796 / GRB 251028143)
  18. GRB 251028A: Fermi GBM Final Real-time Localization
  19. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  20. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  21. GRB 251025C: Glowbug gamma-ray detection
  22. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  23. Konus-Wind detection of GRB 251022A
  24. GRB 251022A: SVOM/GRM observation
  25. GRB 251026B: Swift ToO observations
  26. Konus-Wind detection of GRB 251016A (short/hard)
  27. GRB 251026B: Tentative GOTO optical counterpart candidate
  28. GRB 251025C: CALET Gamma-Ray Burst Monitor detection
  29. Fermi GRB 251026B: Global MASTER-Net observations report
  30. Fermi GRB 251025C: Global MASTER-Net observations report
  31. GRB 251026B: Fermi GBM Final Localization
  32. GRB 251023A: SVOM/GRM observation
  33. GRB 251025C: Fermi GBM Final Real-time Localization
  34. Konus-Wind detection of GRB 251016B
  35. IceCube-251025A - IceCube observation of a high-energy neutrino candidate track-like event
  36. GRB 251003A: VLA Detection
  37. GRB 251022A: KAIT optical observations
  38. GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
  39. GRB 251022A: Swift-XRT detection of GOTO25iym
  40. GRB 251022A: GROWTH-India Telescope optical observations
  41. GRB 251022A: Fermi GBM Observation
  42. GRB 251022A: Swift/BAT-GUANO localization skymap of a burst
  43. GRB 251023A: Glowbug gamma-ray detection
  44. IPN triangulation of GRB 251016B
  45. GRB 251013C: further SAO RAS optical observations
  46. GRB 251022A: COLIBRÍ optical observations
  47. GRB 251013C: ISON-Castelgrande observatory optical observations
  48. GRB 251022A: MASTER OT detection
  49. GRB 251022A: DDOTI Optical Detection
  50. Fermi GRB 251023A: Global MASTER-Net observations report
  51. GRB 251022A: GOTO optical counterpart detection
  52. GRB 251023A: Fermi GBM Final Localization Correction
  53. GRB 251022A: Fermi-LAT detection
  54. GRB 251016B: Fermi GBM Detection
  55. GRB 251022A: Tiled Swift observations
  56. GRB 251022A: Fermi GBM Final Real-time Localization
  57. GRB 251021A/EP251021b: Fermi-GBM Sub-Threshold Detection
  58. GRB 251016A: SVOM/ECLAIRs refined analysis
  59. Fermi-LAT gamma-ray observations of IceCube-251018A
  60. GRB 251016A: Fermi GBM Observation
  61. GRB 251018A: Fermi GBM Observation
  62. GRB 251018A: BOOTES-5 and BOOTES-7 early optical detections
  63. Fermi trigger No 782500909: Global MASTER-Net observations report
  64. GRB 251016A: HXMT/HE detection
  65. GRB 251016A: Swift/UVOT Detection
  66. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event
  67. GRB 251016A: VLT/FORS2 Optical Observation
  68. GRB 251018A: MASTER OT detection
  69. GRB 251018A: Fermi GBM Final Real-time Localization
  70. GRB 251011A: Fermi GBM Observation
  71. GRB 251013C: Liverpool Telescope observations
  72. GRB 251013C: Leavitt Observatory optical photometry
  73. Fermi GRB 251016B: Global MASTER-Net observations report
  74. GRB 251016A: AstroSat CZTI detection of a short burst
  75. GRB 251016B: AstroSat CZTI detection
  76. GRB 251016A: CALET Gamma-Ray Burst Monitor detection
  77. GRB 251016B: CALET Gamma-Ray Burst Monitor detection
  78. GRB 251013C: JinShan observations of the non-thermal rebrightening of the optical counterpart
  79. GRB 251016B: Fermi GBM Final Real-time Localization
  80. GRB 251016A: BOOTES-6/DPRT optical upper limit
  81. GRB 251016A: Glowbug gamma-ray detection of a short burst
  82. GRB 251013C: VLA detection
  83. Fermi GRB 251016A: Global MASTER-Net observations report
  84. GRB 251016A: Fermi GBM Final Localization
  85. GRB 251016A: SVOM detection of a short burst
  86. GRB 251014B: PRIME J-band upper limit
  87. GRB 251013C: Kilonova-Catcher optical afterglow detection
  88. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  89. GRB 251013D: Swift/UVOT Observations
  90. GRB 251013C: Swift/UVOT Detection
  91. Konus-Wind detection of GRB 251007A
  92. Fermi Gamma-ray Burst Monitor trigger 782237334/251015673 is not a GRB
  93. GRB 251015A: Fermi GBM Final Real-time Localization
  94. GRB 251013C: SVOM/ECLAIRs refined analysis
  95. GRB 251013D: Swift-XRT observations
  96. GRB 251014B: Swift-XRT observations
  97. GRB 251014B: VLT/FORS2 Optical Observation
  98. GRB 251011B: SVOM/VT optical upper limit
  99. GRB 251013D: Fermi GBM Observation
  100. IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event

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