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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"

45899 results found.

  1. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  2. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  3. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  4. Fermi GRB 260115A: Global MASTER-Net observations report
  5. GRB 260115A: Fermi GBM Final Real-time Localization
  6. GRB260114A: STEP/T80S optical limits
  7. GRB 251222A: radio detection with the VLA
  8. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  9. Konus-Wind detection of GRB 260114A
  10. GRB 260114A: Swift-XRT refined Analysis
  11. GRB 260114A: 6 GHz VLA observations
  12. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  13. GRB 260114A : MITSuME Akeno optical upper limits
  14. GRB 260114A: COLIBRÍ optical upper limits
  15. GRB 260114A: TNG NIR upper limit
  16. GRB 260114A: NOT optical observations
  17. Konus-Wind detection of GRB 251230A / EP251230a
  18. GRB 260114A: SVOM/GRM observation of a short burst
  19. Swift GRB 260114A: Global MASTER-Net observations report
  20. GRB 260114A: GECAM-B observation of a short burst
  21. GRB 260114A: Mondy optical observations
  22. GRB 260114A: Fermi GBM observation
  23. GRB 260112B: GECAM-B observation
  24. GRB 260114A: GMG Optical Observation
  25. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  26. GRB 260114A: Swift detection of a short burst
  27. GRB 260114A: Fermi GBM Final Real-time Localization
  28. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  29. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  30. Swift GRB260113.43: Global MASTER-Net observations report
  31. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  32. EP260110a: TRT optical upper limits
  33. Konus-Wind detection of GRB 260101A
  34. GRB 260111A: Swift-XRT observations
  35. Swift Trigger 1439093: is probably not GRB 260113A
  36. GRB 260111A: COLIBRÍ optical afterglow candidate
  37. GRB 260111A: GECAM-B observation of a burst
  38. GRB 260111A: Fermi GBM Observation
  39. The EP-WXT trigger 01709251266 is likely a flaring star
  40. Swift Trigger 1434591 is not a GRB
  41. GRB 260111A: GOTO optical upper limits
  42. GRB 260112B: Fermi GBM Final Real-time Localization
  43. GRB 260111A: Swift ToO observations
  44. GRB 251230A: Mondy Optical Observations
  45. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  46. GRB 260112A: Fermi GBM Final Real-time Localization
  47. EP260110a: SVOM/VT optical upper limits
  48. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  49. IceCube Alert 260111A: Global MASTER-Net observations report
  50. EP260110a: Global MASTER-Net observations report
  51. Fermi GRB 260111A: Global MASTER-Net observations report
  52. GRB 260111A: Fermi GBM Final Real-time Localization
  53. Swift trigger 1436759 is not an astrophysical event
  54. EP260110a: KAIT optical upper limit
  55. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  56. EP 260110a: COLIBRÍ optical observations
  57. EP260110a: SVOM/C-GFT upper limit
  58. EP260110a: BOOTES-5/JGU optical upper limit
  59. EP260110a: Einstein Probe detection of an X-ray transient
  60. GRB 260109C: LCO optical upper limits
  61. GRB 260109C: Kilonova-Catcher optical upper limit
  62. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  63. Swift Trigger 1434591: possible GRB 260109C
  64. GRB 260109B: Fermi GBM Final Real-time Localization
  65. GRB 260102A: Swift-XRT afterglow detection
  66. GRB 260109A: Fermi GBM Final Real-time Localization
  67. GRB 260104A: Swift-BAT refined analysis
  68. GRB 260101A: Swift-BAT refined analysis
  69. Swift GRB 251230A: Global MASTER-Net OT detection
  70. Fermi GRB 260107A: Global MASTER-Net observations report
  71. GRB 260102A: AbAO optical observations
  72. GRB 260107A: Fermi GBM Final Real-time Localization
  73. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  74. The EP-WXT trigger 01709251112 is likely a flaring star
  75. Fermi GRB 260105A: Global MASTER-Net observations report
  76. GRB 260105B: Fermi GBM Detection
  77. EP260105a: FTW optical observations
  78. EP260104a: FTW optical observations
  79. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  80. GRB 260105A: SVOM/GRM observation
  81. GRB 260105B: SVOM/GRM observation
  82. The EP-WXT trigger 01709251028 is likely a flaring star
  83. FRB 20251229A: COLIBRÍ optical upper limits
  84. Fermi GRB 260105B: Global MASTER-Net observations report
  85. EP260105a: SVOM/VT optical upperlimit
  86. GRB 260105B: Fermi GBM Final Real-time Localization
  87. GRB 260105A: Fermi GBM Final Real-time Localization
  88. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  89. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  90. EP260105a: LCO Optical Upper limit
  91. EP260104a: Global MASTER-Net observations report
  92. EP260104a: Einstein Probe detection of a fast X-ray transient
  93. GRB 260101A: COLIBRÍ optical upper limits
  94. EP260105a: Global MASTER-Net observations report
  95. EP260105a: Einstein Probe detection of an X-ray transient
  96. GRB 260103A: Insight-HXMT/HE detection
  97. GRB 260104A: COLIBRÍ optical upper limits
  98. GRB 260104C: Fermi GBM Final Real-time Localization
  99. Fermi GRB 260104B: Global MASTER-Net observations report
  100. Swift GRB 260104A: Global MASTER-Net observations report

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