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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"

45596 results found.

  1. GRB 251222A / EP251222b: GECAM-B observation
  2. EP251221a: Liverpool Telescope upper limits
  3. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  4. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  5. Konus-Wind detection of GRB 251222A / EP251222b
  6. GRB 251222A: Swift-XRT afterglow detection
  7. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  8. EP251222a: NTT/ULTRACAM optical observations
  9. EP251222a: GOTO optical upper limit
  10. GRB 251222A / EP251222b: GOTO optical counterpart detection
  11. GRB 251222A / EP251222b: LCO optical observations
  12. GRB 251222A: 1.3m DFOT optical detection
  13. GRB251221A: 7DT optical upper limits
  14. EP251222a: GSP Optical Counterpart Detection
  15. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  16. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  17. EP251222b/GRB 251222A: SVOM/GRM observation
  18. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  19. EP251222a: Einstein Probe detection of an X-ray transient
  20. The EP-WXT trigger 01709250397 is likely a flaring star
  21. EP251221a: Global MASTER-Net observations report
  22. GRB 251222A: PRIME near-infrared detection
  23. EP251221a: NOT optical upper limit
  24. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  25. GRB 251222A: NOT optical observations
  26. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  27. IPN triangulation of GRB 251220B (short)
  28. GRB 251222A: Swift ToO observations
  29. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  30. GRB 251222A: SVOM/VT optical candidate
  31. GRB 251222A: SVOM detection of a long burst
  32. SVOM GRB251222A: Global MASTER-Net observations report
  33. GRB 251222A: Fermi GBM Final Real-time Localization
  34. EP251220a: PRIME upper limit
  35. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  36. GRB 251221A: PRIME near-infrared observation
  37. EP251220a: NOT optical observations
  38. EP251220a: FTW optical and NIR observations
  39. GRB 251221A: UAFO and Mondy optical upper limit
  40. GRB 251221A: Swift-XRT refined Analysis
  41. EP251221a: Einstein Probe detection of a fast X-ray transient
  42. GRB 251221A: Swift/UVOT Upper Limits
  43. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  44. GRB 251221A: Enhanced Swift-XRT position
  45. GRB 251221A: Fermi GBM Observation
  46. GRB 251221B: Fermi GBM Final Real-time Localization
  47. EP251220a: EP-FXT follow-up observation
  48. GRB 251220B: SVOM/GRM observation of a short burst
  49. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  50. EP 251220a: GOTO optical counterpart detection
  51. GRB 251221A: COLIBRÍ detection of the optical counterpart
  52. EP 251220a: COLIBRÍ detection of the optical counterpart
  53. GRB 251221A: Swift detection of a burst
  54. Swift GRB251221A: Global MASTER-Net observations report
  55. GRB 251221A: Fermi GBM Final Real-time Localization
  56. EP251220a: Global MASTER-Net observations report
  57. EP251220a: EP detection of a fast X-ray transient
  58. SVOM GRB251220.98: Global MASTER-Net observations report
  59. GRB 251220B: Fermi GBM Final Real-time Localization
  60. GRB 251219A: SVOM/GRM observation of a short burst
  61. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  62. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  63. GRB 251220A: MAXI/GSC detection
  64. GRB 251215A: Swift-XRT afterglow detection
  65. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  66. IceCube-251218A: COLIBRÍ optical upper limits
  67. SVOM GRB251219.11: Global MASTER-Net observations report
  68. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  69. IceCube Alert 251218.85: Global MASTER-Net observations report
  70. GRB 251214B: VIRT Optical Upper Limit
  71. Fermi trigger No 787736968: Global MASTER-Net observations report
  72. Fermi GRB 251217A: Global MASTER-Net observations report
  73. GRB 251217A: Fermi GBM Final Real-time Localization
  74. GRB 251215A: Swift/UVOT Upper LImits
  75. GRB 251215A: Fermi GBM Observation
  76. Fermi GRB 251216A: Global MASTER-Net observations report
  77. GRB 251202A/EP251202a: Koshka optical upper limit
  78. GRB 251214B: Mondy optical upper limit
  79. GRB 251215A: COLIBRÍ optical upper limit
  80. GRB 251216A: Fermi GBM Final Real-time Localization
  81. EP251214b: KAIT optical upper limit
  82. GRB 251215A: Swift-XRT observations
  83. Fermi GRB 251215A: Global MASTER-Net observations report
  84. EP251214a: Optical upper limit with Kinder observations
  85. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  86. GRB 251215A: Glowbug gamma-ray detection
  87. GRB 251214B: UAFO optical upper limit
  88. GRB 251214B: VLT/X-shooter observations
  89. GRB 251213A: GRID-10B observation
  90. GRB 251214B: Swift-BAT refined analysis
  91. GRB 251202A: radio detection with the VLA
  92. EP251214b: Global MASTER-Net observations report
  93. EP251214b : Einstein Probe detection of a fast X-ray transient
  94. EP251214b : Einstein Probe detection of a fast X-ray transient
  95. GRB 251214B: AbAO optical observations
  96. GRB 251214B: LCO detection of the optical counterpart
  97. GRB 251209A: GECAM-B observation of a long burst
  98. GRB 251214D: GECAM-B observation of a long burst
  99. GRB 251214B: Fermi GBM Observation
  100. GRB 251209A: Insight-HXMT/HE detection

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