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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"

32714 results found.

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

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