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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"

12390 results found.

  1. GRB 251025A: SVOM/VT VHF optical upper limit
  2. GRB 251024A: Swift detection of a burst
  3. Swift GRB 251024A: Global MASTER-Net observations report
  4. GRB 251022A: COLIBRÍ Further Multi-frequency Optical Observations
  5. GRB 251023B: OHP/T193 optical observations
  6. GRB 251022A: Swift-XRT detection of GOTO25iym
  7. EP251023b: Global MASTER-Net observations report
  8. EP251023a: Global MASTER-Net observations report
  9. EP#01709247298: Swift-XRT counterpart detection
  10. GRB 251023B / MAXI J0451+122: MAXI/GSC detection
  11. Fermi GRB 251023A: Global MASTER-Net observations report
  12. LAT GRB251022A: Global MASTER-Net observations report
  13. EP251021b: BOOTES-7 optical upper limit
  14. GRB 250911A: MAXI/GSC detection
  15. Fermi-LAT gamma-ray observations of IceCube-251018A
  16. GRB 251017A : RAPAS follow-up observations
  17. IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
  18. IceCube-251018A: DDOTI Optical Upper Limit
  19. Fermi trigger No 782500909: Global MASTER-Net observations report
  20. IceCube-251018A: Global MASTER-Net observations report
  21. GRB 251017A: Swift/UVOT Detection
  22. GRB 251016A: Swift/UVOT Detection
  23. Swift GRB 251018A: Global MASTER-Net observations report
  24. Fermi GRB 251016B: Global MASTER-Net observations report
  25. Swift GRB 251017A: Global MASTER-Net observations report
  26. GRB 251016A: BOOTES-6/DPRT optical upper limit
  27. sb25101602: Swift-XRT counterpart detection
  28. Fermi GRB 251016A: Global MASTER-Net observations report
  29. GRB 251014A: Swift-XRT observations
  30. GRB 251014B: PRIME J-band upper limit
  31. Upper limits from a search for additional neutrino events in IceCube
  32. IceCube Alert 251014.77: Global MASTER-Net observations report
  33. Swift GRB251015.60: Global MASTER-Net observations report
  34. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  35. GRB 251013D: Swift/UVOT Observations
  36. GRB 251013C: Swift/UVOT Detection
  37. Konus-Wind detection of GRB 251007A
  38. GRB 251013D: Swift-XRT observations
  39. Swift Trigger 1404295: possible GRB 251015A
  40. GRB 251014B: Swift-XRT observations
  41. GRB 251014B: Swift/UVOT Upper Limits
  42. GRB 251014D: Swift/UVOT Upper Limits
  43. GRB 251014D: BOOTES-6/DPRT optical upper limit
  44. GRB 251011B: SVOM/VT optical upper limit
  45. GRB 251014D: Swift detection of a burst
  46. GRB 251014A: PRIME near-infrared upper limits
  47. GRB 251013D: LAST optical upper limit on Swift/BAT-GUANO localization
  48. GRB 251014A: DDOTI Upper Limit
  49. GRB 251014A: SAO RAS optical upper limit
  50. Swift GRB 251014A: Global MASTER-Net observations report
  51. Fermi trigger No 782044789: Global MASTER-Net observations report
  52. Fermi GRB 251013C: Global MASTER-Net observations report
  53. Fermi GRB 251013B: Global MASTER-Net observations report
  54. Fermi GRB 251013D: Global MASTER-Net observations report
  55. GRB 251013C: Swift-XRT counterpart detection
  56. GRB 251003A: Mondy optical upper limit
  57. Fermi GRB 251013A: Global MASTER-Net observations report
  58. GRB 251011B: Swift/UVOT Upper Limits
  59. Fermi GRB 251011A: Global MASTER-Net observations report
  60. GRB 251007B: Swift/UVOT Upper Limits
  61. EP251006a: Global MASTER-Net observations report
  62. IceCube Alert 251008A: Global MASTER-Net observations report
  63. GRB 251007B: COLIBRÍ optical upper limit
  64. GRB 250917B: iTelescope T-26 upper limit
  65. EP250911a: Koshka Zeiss-1000 Optical Upper Limit
  66. GRB 251007A: AKO Optical Upper Limit
  67. GRB 251005C: PRIME J-band upper limit
  68. Swift GRB 251007B: Global MASTER-Net observations report
  69. GRB 251007B: SVOM/C-GFT upper limit
  70. Swift GRB 251007A: Global MASTER-Net observations report
  71. GRB 250702B/EP250702a: JWST/NIRCam Observations
  72. GRB 251006B: COLIBRÍ optical upper limit
  73. Fermi GRB 251006B: Global MASTER-Net observations report
  74. Fermi GRB 251006A: Global MASTER-Net observations report
  75. GRB 251005C: Swift/UVOT Upper Limits
  76. Swift GRB 251005A: Global MASTER-Net observations report
  77. GRB 251005C: GOTO optical upper limits
  78. Fermi trigger No 781367244: Global MASTER-Net observations report
  79. GRB 251005C: Swift detection of a burst
  80. GRB 251002A: NIR observations with WINTER
  81. GRB 251001B: NIR observations with WINTER
  82. GRB 251003A: Swift/UVOT Upper Limits
  83. EP250821a: iTelescope T-59 possible detection of the optical counterpart
  84. GRB 251002A: Swift-XRT afterglow detection
  85. GRB 251001B: AbAO optical upper limit
  86. GRB 251003A: Swift detection of a burst
  87. Swift GRB251003A: Global MASTER-Net observations report
  88. Fermi GRB 251002A: Global MASTER-Net observations report
  89. Swift GRB 251001B: Global MASTER-Net observations report
  90. Fermi GRB 250929A: Global MASTER-Net observations report
  91. Fermi-LAT Gamma-ray Observations of IceCube-250926A
  92. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  93. Fermi trigger No 780609036: Global MASTER-Net observations report
  94. IceCube Alert 250926.52: Global MASTER-Net observations report
  95. GRB 250925A: Swift/UVOT Upper Limits
  96. GRB 250925A: COLIBRÍ photometric redshift
  97. GRB 250925A: SVOM/GWAC-F60A upper limit
  98. GRB 250925A : MITSuME Akeno optical upper limits
  99. Fermi GRB 250926A: Global MASTER-Net observations report
  100. GRB 250925A: Leavitt Observatory optical upper limit

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