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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"

32724 results found.

  1. EP260119a: preliminary result from the EP-FXT observation
  2. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  3. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  4. Swift trigger on the HMXB 1A 1118-61
  5. GRB 260117A: SVOM/VT optical candidate
  6. GRB 260117A: SVOM/C-GFT upper limit
  7. GRB 260117A: Swift ToO observations
  8. EP 260116a: COLIBRÍ optical upper limit
  9. GRB 260115A: GECAM-B observation
  10. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  11. EP260116a: Liverpool Telescope upper limits
  12. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  13. EP260116A: 1.3m DFOT optical upper limit
  14. GRB 260114A: VLT/MUSE spectroscopic observations
  15. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  16. EP260116a: Global MASTER-Net observations report
  17. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  18. EP260116a: Xinglong optical upper limit
  19. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  20. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  21. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  22. Fermi GRB 260115A: Global MASTER-Net observations report
  23. GRB260114A: STEP/T80S optical limits
  24. GRB 251222A: radio detection with the VLA
  25. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  26. Konus-Wind detection of GRB 260114A
  27. GRB 260114A: 6 GHz VLA observations
  28. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  29. GRB 260114A : MITSuME Akeno optical upper limits
  30. GRB 260114A: COLIBRÍ optical upper limits
  31. GRB 260114A: TNG NIR upper limit
  32. GRB 260114A: NOT optical observations
  33. Konus-Wind detection of GRB 251230A / EP251230a
  34. GRB 260114A: SVOM/GRM observation of a short burst
  35. Swift GRB 260114A: Global MASTER-Net observations report
  36. GRB 260114A: GECAM-B observation of a short burst
  37. GRB 260114A: Mondy optical observations
  38. GRB 260114A: Fermi GBM observation
  39. GRB 260112B: GECAM-B observation
  40. GRB 260114A: GMG Optical Observation
  41. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  42. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  43. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  44. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  45. EP260110a: TRT optical upper limits
  46. Konus-Wind detection of GRB 260101A
  47. GRB 260111A: Swift-XRT observations
  48. GRB 260111A: COLIBRÍ optical afterglow candidate
  49. GRB 260111A: GECAM-B observation of a burst
  50. GRB 260111A: Fermi GBM Observation
  51. Swift Trigger 1434591 is not a GRB
  52. GRB 260111A: GOTO optical upper limits
  53. GRB 260111A: Swift ToO observations
  54. GRB 251230A: Mondy Optical Observations
  55. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  56. EP260110a: SVOM/VT optical upper limits
  57. EP260110a: Global MASTER-Net observations report
  58. Fermi GRB 260111A: Global MASTER-Net observations report
  59. EP260110a: KAIT optical upper limit
  60. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  61. EP 260110a: COLIBRÍ optical observations
  62. EP260110a: SVOM/C-GFT upper limit
  63. EP260110a: BOOTES-5/JGU optical upper limit
  64. GRB 260109C: LCO optical upper limits
  65. GRB 260109C: Kilonova-Catcher optical upper limit
  66. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  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. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  73. Fermi GRB 260105A: Global MASTER-Net observations report
  74. EP260105a: FTW optical observations
  75. EP260104a: FTW optical observations
  76. GRB 260105A: SVOM/GRM observation
  77. GRB 260105B: SVOM/GRM observation
  78. FRB 20251229A: COLIBRÍ optical upper limits
  79. Fermi GRB 260105B: Global MASTER-Net observations report
  80. EP260105a: SVOM/VT optical upperlimit
  81. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  82. EP260105a: LCO Optical Upper limit
  83. EP260104a: Global MASTER-Net observations report
  84. GRB 260101A: COLIBRÍ optical upper limits
  85. EP260105a: Global MASTER-Net observations report
  86. GRB 260103A: Insight-HXMT/HE detection
  87. GRB 260104A: COLIBRÍ optical upper limits
  88. Fermi GRB 260104B: Global MASTER-Net observations report
  89. Swift GRB 260104A: Global MASTER-Net observations report
  90. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  91. GRB 260101A: Swift/UVOT Detection
  92. GRB 260103A: GECAM-B observation of a burst
  93. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  94. GRB 260101A: COLIBRÍ optical observations
  95. Fermi GBM Sub-Threshold Detection of GRB 260102A
  96. GRB 260102A: EP-FXT follow-up observation
  97. EP260101a: Global MASTER-Net observations report
  98. GRB 260102A: LCO optical upper limits
  99. GRB 260102A: Swift-XRT observations
  100. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations

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