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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"

32720 results found.

  1. GRB 260117A: SVOM/VT optical candidate
  2. GRB 260117A: SVOM/C-GFT upper limit
  3. GRB 260117A: Swift ToO observations
  4. EP 260116a: COLIBRÍ optical upper limit
  5. GRB 260115A: GECAM-B observation
  6. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  7. EP260116a: Liverpool Telescope upper limits
  8. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  9. EP260116A: 1.3m DFOT optical upper limit
  10. GRB 260114A: VLT/MUSE spectroscopic observations
  11. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  12. EP260116a: Global MASTER-Net observations report
  13. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  14. EP260116a: Xinglong optical upper limit
  15. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  16. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  17. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  18. Fermi GRB 260115A: Global MASTER-Net observations report
  19. GRB260114A: STEP/T80S optical limits
  20. GRB 251222A: radio detection with the VLA
  21. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  22. Konus-Wind detection of GRB 260114A
  23. GRB 260114A: 6 GHz VLA observations
  24. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  25. GRB 260114A : MITSuME Akeno optical upper limits
  26. GRB 260114A: COLIBRÍ optical upper limits
  27. GRB 260114A: TNG NIR upper limit
  28. GRB 260114A: NOT optical observations
  29. Konus-Wind detection of GRB 251230A / EP251230a
  30. GRB 260114A: SVOM/GRM observation of a short burst
  31. Swift GRB 260114A: Global MASTER-Net observations report
  32. GRB 260114A: GECAM-B observation of a short burst
  33. GRB 260114A: Mondy optical observations
  34. GRB 260114A: Fermi GBM observation
  35. GRB 260112B: GECAM-B observation
  36. GRB 260114A: GMG Optical Observation
  37. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  38. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  39. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  40. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  41. EP260110a: TRT optical upper limits
  42. Konus-Wind detection of GRB 260101A
  43. GRB 260111A: Swift-XRT observations
  44. GRB 260111A: COLIBRÍ optical afterglow candidate
  45. GRB 260111A: GECAM-B observation of a burst
  46. GRB 260111A: Fermi GBM Observation
  47. Swift Trigger 1434591 is not a GRB
  48. GRB 260111A: GOTO optical upper limits
  49. GRB 260111A: Swift ToO observations
  50. GRB 251230A: Mondy Optical Observations
  51. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  52. EP260110a: SVOM/VT optical upper limits
  53. EP260110a: Global MASTER-Net observations report
  54. Fermi GRB 260111A: Global MASTER-Net observations report
  55. EP260110a: KAIT optical upper limit
  56. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  57. EP 260110a: COLIBRÍ optical observations
  58. EP260110a: SVOM/C-GFT upper limit
  59. EP260110a: BOOTES-5/JGU optical upper limit
  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. GRB 260104A: Swift-BAT refined analysis
  64. GRB 260101A: Swift-BAT refined analysis
  65. Swift GRB 251230A: Global MASTER-Net OT detection
  66. Fermi GRB 260107A: Global MASTER-Net observations report
  67. GRB 260102A: AbAO optical observations
  68. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  69. Fermi GRB 260105A: Global MASTER-Net observations report
  70. EP260105a: FTW optical observations
  71. EP260104a: FTW optical observations
  72. GRB 260105A: SVOM/GRM observation
  73. GRB 260105B: SVOM/GRM observation
  74. FRB 20251229A: COLIBRÍ optical upper limits
  75. Fermi GRB 260105B: Global MASTER-Net observations report
  76. EP260105a: SVOM/VT optical upperlimit
  77. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  78. EP260105a: LCO Optical Upper limit
  79. EP260104a: Global MASTER-Net observations report
  80. GRB 260101A: COLIBRÍ optical upper limits
  81. EP260105a: Global MASTER-Net observations report
  82. GRB 260103A: Insight-HXMT/HE detection
  83. GRB 260104A: COLIBRÍ optical upper limits
  84. Fermi GRB 260104B: Global MASTER-Net observations report
  85. Swift GRB 260104A: Global MASTER-Net observations report
  86. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  87. GRB 260101A: Swift/UVOT Detection
  88. GRB 260103A: GECAM-B observation of a burst
  89. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  90. GRB 260101A: COLIBRÍ optical observations
  91. Fermi GBM Sub-Threshold Detection of GRB 260102A
  92. GRB 260102A: EP-FXT follow-up observation
  93. EP260101a: Global MASTER-Net observations report
  94. GRB 260102A: LCO optical upper limits
  95. GRB 260102A: Swift-XRT observations
  96. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  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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