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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

35431 results found.

  1. GRB 260110A: SVOM detection of a burst through offline search
  2. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  3. GRB 260117A: SVOM/VT optical candidate
  4. GRB 260117A: SVOM/C-GFT upper limit
  5. GRB 260117A: Swift-XRT observations
  6. GRB 260117A: Swift ToO observations
  7. GRB 260117A: SVOM detection of a long faint burst
  8. GRB 260115A: GECAM-B observation
  9. GRB 260114A: VLT/MUSE spectroscopic observations
  10. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  11. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  12. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  13. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  14. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  15. Fermi GRB 260115A: Global MASTER-Net observations report
  16. GRB 260115A: Fermi GBM Final Real-time Localization
  17. GRB 251222A: radio detection with the VLA
  18. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  19. Konus-Wind detection of GRB 260114A
  20. GRB 260114A: Swift-XRT refined Analysis
  21. GRB 260114A: 6 GHz VLA observations
  22. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  23. GRB 260114A : MITSuME Akeno optical upper limits
  24. GRB 260114A: COLIBRÍ optical upper limits
  25. GRB 260114A: TNG NIR upper limit
  26. GRB 260114A: NOT optical observations
  27. Konus-Wind detection of GRB 251230A / EP251230a
  28. GRB 260114A: SVOM/GRM observation of a short burst
  29. Swift GRB 260114A: Global MASTER-Net observations report
  30. GRB 260114A: GECAM-B observation of a short burst
  31. GRB 260114A: Mondy optical observations
  32. GRB 260114A: Fermi GBM observation
  33. GRB 260112B: GECAM-B observation
  34. GRB 260114A: GMG Optical Observation
  35. GRB 260114A: Swift detection of a short burst
  36. GRB 260114A: Fermi GBM Final Real-time Localization
  37. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  38. Konus-Wind detection of GRB 260101A
  39. GRB 260111A: Swift-XRT observations
  40. Swift Trigger 1439093: is probably not GRB 260113A
  41. GRB 260111A: COLIBRÍ optical afterglow candidate
  42. GRB 260111A: GECAM-B observation of a burst
  43. GRB 260111A: Fermi GBM Observation
  44. Swift Trigger 1434591 is not a GRB
  45. GRB 260111A: GOTO optical upper limits
  46. GRB 260112B: Fermi GBM Final Real-time Localization
  47. GRB 260111A: Swift ToO observations
  48. GRB 251230A: Mondy Optical Observations
  49. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  50. GRB 260112A: Fermi GBM Final Real-time Localization
  51. Fermi GRB 260111A: Global MASTER-Net observations report
  52. GRB 260111A: Fermi GBM Final Real-time Localization
  53. EP260110a: KAIT optical upper limit
  54. GRB 260109C: LCO optical upper limits
  55. GRB 260109C: Kilonova-Catcher optical upper limit
  56. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  57. Swift Trigger 1434591: possible GRB 260109C
  58. GRB 260109B: Fermi GBM Final Real-time Localization
  59. GRB 260102A: Swift-XRT afterglow detection
  60. GRB 260109A: Fermi GBM Final Real-time Localization
  61. GRB 260104A: Swift-BAT refined analysis
  62. GRB 260101A: Swift-BAT refined analysis
  63. Swift GRB 251230A: Global MASTER-Net OT detection
  64. Fermi GRB 260107A: Global MASTER-Net observations report
  65. GRB 260102A: AbAO optical observations
  66. GRB 260107A: Fermi GBM Final Real-time Localization
  67. Fermi GRB 260105A: Global MASTER-Net observations report
  68. GRB 260105B: Fermi GBM Detection
  69. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  70. GRB 260105A: SVOM/GRM observation
  71. GRB 260105B: SVOM/GRM observation
  72. Fermi GRB 260105B: Global MASTER-Net observations report
  73. GRB 260105B: Fermi GBM Final Real-time Localization
  74. GRB 260105A: Fermi GBM Final Real-time Localization
  75. GRB 260101A: COLIBRÍ optical upper limits
  76. GRB 260103A: Insight-HXMT/HE detection
  77. GRB 260104A: COLIBRÍ optical upper limits
  78. GRB 260104C: Fermi GBM Final Real-time Localization
  79. Fermi GRB 260104B: Global MASTER-Net observations report
  80. Swift GRB 260104A: Global MASTER-Net observations report
  81. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  82. GRB 260104A: Swift-XRT refined Analysis
  83. GRB 260104A: Enhanced Swift-XRT position
  84. GRB 260101A: Swift/UVOT Detection
  85. GRB 260103A: GECAM-B observation of a burst
  86. GRB 260104B: Fermi GBM Final Localization
  87. GRB 260104A: Swift detection of a burst
  88. GRB 260103A: SVOM/GRM observation of a possible GRB
  89. GRB 260101A: COLIBRÍ optical observations
  90. GRB 260102B: Fermi GBM Final Real-time Localization
  91. Fermi GBM Sub-Threshold Detection of GRB 260102A
  92. GRB 260102A: EP-FXT follow-up observation
  93. GRB 260102A: LCO optical upper limits
  94. GRB 260102A: Swift-XRT observations
  95. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  96. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  97. GRB 251230A / EP251230a: GECAM-B detection
  98. GRB 260102A: SVOM/VT optical counterpart
  99. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  100. GRB 260102A: Swift ToO observations

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