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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"

29105 results found.

  1. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  2. EP251222a: NTT/ULTRACAM optical observations
  3. EP251222a: GOTO optical upper limit
  4. GRB 251222A / EP251222b: GOTO optical counterpart detection
  5. GRB 251222A / EP251222b: LCO optical observations
  6. GRB 251222A: 1.3m DFOT optical detection
  7. GRB251221A: 7DT optical upper limits
  8. EP251222a: GSP Optical Counterpart Detection
  9. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  10. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  11. EP251222b/GRB 251222A: SVOM/GRM observation
  12. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  13. The EP-WXT trigger 01709250397 is likely a flaring star
  14. EP251221a: Global MASTER-Net observations report
  15. GRB 251222A: PRIME near-infrared detection
  16. EP251221a: NOT optical upper limit
  17. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  18. GRB 251222A: NOT optical observations
  19. IPN triangulation of GRB 251220B (short)
  20. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  21. GRB 251222A: SVOM/VT optical candidate
  22. GRB 251222A: SVOM detection of a long burst
  23. SVOM GRB251222A: Global MASTER-Net observations report
  24. GRB 251222A: Fermi GBM Final Real-time Localization
  25. EP251220a: PRIME upper limit
  26. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  27. GRB 251221A: PRIME near-infrared observation
  28. EP251220a: NOT optical observations
  29. EP251220a: FTW optical and NIR observations
  30. GRB 251221A: UAFO and Mondy optical upper limit
  31. GRB 251221A: Swift-XRT refined Analysis
  32. GRB 251221A: Swift/UVOT Upper Limits
  33. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  34. GRB 251221A: Fermi GBM Observation
  35. GRB 251221B: Fermi GBM Final Real-time Localization
  36. GRB 251220B: SVOM/GRM observation of a short burst
  37. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  38. EP 251220a: GOTO optical counterpart detection
  39. GRB 251221A: COLIBRÍ detection of the optical counterpart
  40. EP 251220a: COLIBRÍ detection of the optical counterpart
  41. GRB 251221A: Swift detection of a burst
  42. Swift GRB251221A: Global MASTER-Net observations report
  43. GRB 251221A: Fermi GBM Final Real-time Localization
  44. EP251220a: Global MASTER-Net observations report
  45. EP251220a: EP detection of a fast X-ray transient
  46. SVOM GRB251220.98: Global MASTER-Net observations report
  47. GRB 251220B: Fermi GBM Final Real-time Localization
  48. GRB 251219A: SVOM/GRM observation of a short burst
  49. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  50. IceCube-251218A: COLIBRÍ optical upper limits
  51. SVOM GRB251219.11: Global MASTER-Net observations report
  52. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  53. IceCube Alert 251218.85: Global MASTER-Net observations report
  54. GRB 251214B: VIRT Optical Upper Limit
  55. Fermi trigger No 787736968: Global MASTER-Net observations report
  56. Fermi GRB 251217A: Global MASTER-Net observations report
  57. GRB 251217A: Fermi GBM Final Real-time Localization
  58. GRB 251215A: Swift/UVOT Upper LImits
  59. GRB 251215A: Fermi GBM Observation
  60. Fermi GRB 251216A: Global MASTER-Net observations report
  61. GRB 251202A/EP251202a: Koshka optical upper limit
  62. GRB 251214B: Mondy optical upper limit
  63. GRB 251215A: COLIBRÍ optical upper limit
  64. GRB 251216A: Fermi GBM Final Real-time Localization
  65. EP251214b: KAIT optical upper limit
  66. Fermi GRB 251215A: Global MASTER-Net observations report
  67. EP251214a: Optical upper limit with Kinder observations
  68. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  69. GRB 251215A: Glowbug gamma-ray detection
  70. GRB 251214B: UAFO optical upper limit
  71. GRB 251214B: VLT/X-shooter observations
  72. GRB 251214B: Swift-BAT refined analysis
  73. GRB 251202A: radio detection with the VLA
  74. EP251214b: Global MASTER-Net observations report
  75. GRB 251214B: AbAO optical observations
  76. GRB 251214B: LCO detection of the optical counterpart
  77. GRB 251209A: GECAM-B observation of a long burst
  78. GRB 251214B: Fermi GBM Observation
  79. GRB 251209A: Insight-HXMT/HE detection
  80. EP251214b (EP trigger 01709250023): LCO optical limits
  81. GRB 251203B: AbAO optical observations
  82. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  83. GRB 251214B: GECAM-B observation of a long burst
  84. GRB 251214B: Swift-XRT refined Analysis
  85. GRB 251213A: SVOM/GRM observation
  86. GRB 251214A: AstroSat CZTI detection
  87. GRB 251213A: GECAM-B detection
  88. GRB 251214B: Swift/UVOT Detection
  89. GRB 251215A: Fermi GBM Final Real-time Localization
  90. GRB 251214B: COLIBRÍ observations of the afterglow
  91. GRB 251214A: GECAM-B observation of a likely long burst
  92. GRB 251214B: 1.3m DFOT optical detection
  93. EP251214a: Global MASTER-Net observations report
  94. GRB 251214B: Xinglong-2.16m optical observation
  95. GRB 251214C: Fermi GBM Final Localization
  96. GRB 251214B : MASTER optical afterglow detection
  97. Fermi trigger No 787396657: Global MASTER-Net observations report
  98. GRB 251214B: SVOM/C-GFT optical observations
  99. EP251214a: COLIBRÍ optical upper limit
  100. Swift GRB 251214B: Global MASTER-Net observations report

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