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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"

41723 results found.

  1. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  2. EP 251220a: GOTO optical counterpart detection
  3. GRB 251221A: COLIBRÍ detection of the optical counterpart
  4. EP 251220a: COLIBRÍ detection of the optical counterpart
  5. GRB 251221A: Swift detection of a burst
  6. Swift GRB251221A: Global MASTER-Net observations report
  7. GRB 251221A: Fermi GBM Final Real-time Localization
  8. EP251220a: Global MASTER-Net observations report
  9. EP251220a: EP detection of a fast X-ray transient
  10. SVOM GRB251220.98: Global MASTER-Net observations report
  11. GRB 251220B: Fermi GBM Final Real-time Localization
  12. GRB 251219A: SVOM/GRM observation of a short burst
  13. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  14. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  15. GRB 251220A: MAXI/GSC detection
  16. GRB 251215A: Swift-XRT afterglow detection
  17. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  18. IceCube-251218A: COLIBRÍ optical upper limits
  19. SVOM GRB251219.11: Global MASTER-Net observations report
  20. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  21. IceCube Alert 251218.85: Global MASTER-Net observations report
  22. GRB 251214B: VIRT Optical Upper Limit
  23. Fermi trigger No 787736968: Global MASTER-Net observations report
  24. Fermi GRB 251217A: Global MASTER-Net observations report
  25. GRB 251217A: Fermi GBM Final Real-time Localization
  26. GRB 251215A: Swift/UVOT Upper LImits
  27. GRB 251215A: Fermi GBM Observation
  28. Fermi GRB 251216A: Global MASTER-Net observations report
  29. GRB 251202A/EP251202a: Koshka optical upper limit
  30. GRB 251214B: Mondy optical upper limit
  31. GRB 251215A: COLIBRÍ optical upper limit
  32. GRB 251216A: Fermi GBM Final Real-time Localization
  33. EP251214b: KAIT optical upper limit
  34. GRB 251215A: Swift-XRT observations
  35. Fermi GRB 251215A: Global MASTER-Net observations report
  36. EP251214a: Optical upper limit with Kinder observations
  37. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  38. GRB 251215A: Glowbug gamma-ray detection
  39. GRB 251214B: UAFO optical upper limit
  40. GRB 251214B: VLT/X-shooter observations
  41. GRB 251213A: GRID-10B observation
  42. GRB 251214B: Swift-BAT refined analysis
  43. GRB 251202A: radio detection with the VLA
  44. EP251214b: Global MASTER-Net observations report
  45. EP251214b : Einstein Probe detection of a fast X-ray transient
  46. EP251214b : Einstein Probe detection of a fast X-ray transient
  47. GRB 251214B: AbAO optical observations
  48. GRB 251214B: LCO detection of the optical counterpart
  49. GRB 251209A: GECAM-B observation of a long burst
  50. GRB 251214D: GECAM-B observation of a long burst
  51. GRB 251214B: Fermi GBM Observation
  52. GRB 251209A: Insight-HXMT/HE detection
  53. GRB 251215A: Swift ToO observations
  54. EP251214b (EP trigger 01709250023): LCO optical limits
  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. EP251214a: EP-FXT non-detection and upper limit
  70. GRB 251214A: GECAM-B observation of a likely long burst
  71. GRB 251214B: 1.3m DFOT optical detection
  72. EP251214a: Global MASTER-Net observations report
  73. GRB 251214B: Enhanced Swift-XRT position
  74. GRB 251214B: Xinglong-2.16m optical observation
  75. GRB 251214C: Fermi GBM Final Localization
  76. GRB 251214B : MASTER optical afterglow detection
  77. Fermi trigger No 787396657: Global MASTER-Net observations report
  78. GRB 251214B: SVOM/C-GFT optical observations
  79. EP251214a: COLIBRÍ optical upper limit
  80. Swift GRB 251214B: Global MASTER-Net observations report
  81. EP251214.305: COLIBRÍ optical upper limit
  82. GRB 251214B: Swift detection of a burst with an optical counterpart
  83. GRB 251214B: Fermi GBM Final Real-time Localization
  84. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  85. Fermi GRB 251214A: Global MASTER-Net observations report
  86. GRB 251214A: Fermi GBM Final Real-time Localization
  87. EP251212a: Global MASTER-Net observations report
  88. EP251212a: KAIT optical upper limit
  89. EP251212a / GRB 251212A: AstroSat CZTI detection
  90. EP251212a: EP-FXT follow-up observation
  91. GRB 251211B: AstroSat CZTI detection
  92. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  93. GRB 251209A: NuSTAR detection of prompt emission
  94. EP251212a : COLIBRÍ optical upper limit
  95. EP251212a: Einstein Probe detection of an X-ray transient
  96. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  97. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  98. Fermi GRB 251211B: Global MASTER-Net observations report
  99. GRB 251211B: Fermi GBM Final Real-time Localization
  100. IceCube-251210A: DDOTI Optical Upper Limit

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