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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"

42427 results found.

  1. GRB 260117A: Swift ToO observations
  2. GRB 260117A: SVOM detection of a long faint burst
  3. EP 260116a: COLIBRÍ optical upper limit
  4. Swift triggered on the HMXB 1A 1118-61
  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. EP260116a: Einstein Probe detection of an X-ray transient
  16. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  17. IceCube Alert 260115.73: Global MASTER-Net observations report
  18. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  19. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  20. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  21. Fermi GRB 260115A: Global MASTER-Net observations report
  22. GRB 260115A: Fermi GBM Final Real-time Localization
  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: Swift-XRT refined Analysis
  28. GRB 260114A: 6 GHz VLA observations
  29. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  30. GRB 260114A : MITSuME Akeno optical upper limits
  31. GRB 260114A: COLIBRÍ optical upper limits
  32. GRB 260114A: TNG NIR upper limit
  33. GRB 260114A: NOT optical observations
  34. Konus-Wind detection of GRB 251230A / EP251230a
  35. GRB 260114A: SVOM/GRM observation of a short burst
  36. Swift GRB 260114A: Global MASTER-Net observations report
  37. GRB 260114A: GECAM-B observation of a short burst
  38. GRB 260114A: Mondy optical observations
  39. GRB 260114A: Fermi GBM observation
  40. GRB 260112B: GECAM-B observation
  41. GRB 260114A: GMG Optical Observation
  42. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  43. GRB 260114A: Swift detection of a short burst
  44. GRB 260114A: Fermi GBM Final Real-time Localization
  45. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  46. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  47. Swift GRB260113.43: Global MASTER-Net observations report
  48. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  49. EP260110a: TRT optical upper limits
  50. Konus-Wind detection of GRB 260101A
  51. GRB 260111A: Swift-XRT observations
  52. Swift Trigger 1439093: is probably not GRB 260113A
  53. GRB 260111A: COLIBRÍ optical afterglow candidate
  54. GRB 260111A: GECAM-B observation of a burst
  55. GRB 260111A: Fermi GBM Observation
  56. The EP-WXT trigger 01709251266 is likely a flaring star
  57. Swift Trigger 1434591 is not a GRB
  58. GRB 260111A: GOTO optical upper limits
  59. GRB 260112B: Fermi GBM Final Real-time Localization
  60. GRB 260111A: Swift ToO observations
  61. GRB 251230A: Mondy Optical Observations
  62. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  63. GRB 260112A: Fermi GBM Final Real-time Localization
  64. EP260110a: SVOM/VT optical upper limits
  65. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  66. IceCube Alert 260111A: Global MASTER-Net observations report
  67. EP260110a: Global MASTER-Net observations report
  68. Fermi GRB 260111A: Global MASTER-Net observations report
  69. GRB 260111A: Fermi GBM Final Real-time Localization
  70. Swift trigger 1436759 is not an astrophysical event
  71. EP260110a: KAIT optical upper limit
  72. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  73. EP 260110a: COLIBRÍ optical observations
  74. EP260110a: SVOM/C-GFT upper limit
  75. EP260110a: BOOTES-5/JGU optical upper limit
  76. EP260110a: Einstein Probe detection of an X-ray transient
  77. GRB 260109C: LCO optical upper limits
  78. GRB 260109C: Kilonova-Catcher optical upper limit
  79. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  80. Swift Trigger 1434591: possible GRB 260109C
  81. GRB 260109B: Fermi GBM Final Real-time Localization
  82. GRB 260102A: Swift-XRT afterglow detection
  83. GRB 260109A: Fermi GBM Final Real-time Localization
  84. GRB 260104A: Swift-BAT refined analysis
  85. GRB 260101A: Swift-BAT refined analysis
  86. Swift GRB 251230A: Global MASTER-Net OT detection
  87. Fermi GRB 260107A: Global MASTER-Net observations report
  88. GRB 260102A: AbAO optical observations
  89. GRB 260107A: Fermi GBM Final Real-time Localization
  90. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  91. The EP-WXT trigger 01709251112 is likely a flaring star
  92. Fermi GRB 260105A: Global MASTER-Net observations report
  93. GRB 260105B: Fermi GBM Detection
  94. EP260105a: FTW optical observations
  95. EP260104a: FTW optical observations
  96. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  97. GRB 260105A: SVOM/GRM observation
  98. GRB 260105B: SVOM/GRM observation
  99. The EP-WXT trigger 01709251028 is likely a flaring star
  100. FRB 20251229A: COLIBRÍ optical upper limits

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