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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"

42435 results found.

  1. Swift GRB260118.48: Global MASTER-Net observations report
  2. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  3. SVOM GRB260117.82: Global MASTER-Net observations report
  4. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  5. Swift trigger on the HMXB 1A 1118-61
  6. GRB 260117A: SVOM/VT optical candidate
  7. GRB 260117A: SVOM/C-GFT upper limit
  8. GRB 260117A: Swift-XRT observations
  9. GRB 260117A: Swift ToO observations
  10. GRB 260117A: SVOM detection of a long faint burst
  11. EP 260116a: COLIBRÍ optical upper limit
  12. Swift triggered on the HMXB 1A 1118-61
  13. GRB 260115A: GECAM-B observation
  14. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  15. EP260116a: Liverpool Telescope upper limits
  16. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  17. EP260116A: 1.3m DFOT optical upper limit
  18. GRB 260114A: VLT/MUSE spectroscopic observations
  19. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  20. EP260116a: Global MASTER-Net observations report
  21. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  22. EP260116a: Xinglong optical upper limit
  23. EP260116a: Einstein Probe detection of an X-ray transient
  24. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  25. IceCube Alert 260115.73: Global MASTER-Net observations report
  26. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  27. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  28. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  29. Fermi GRB 260115A: Global MASTER-Net observations report
  30. GRB 260115A: Fermi GBM Final Real-time Localization
  31. GRB260114A: STEP/T80S optical limits
  32. GRB 251222A: radio detection with the VLA
  33. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  34. Konus-Wind detection of GRB 260114A
  35. GRB 260114A: Swift-XRT refined Analysis
  36. GRB 260114A: 6 GHz VLA observations
  37. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  38. GRB 260114A : MITSuME Akeno optical upper limits
  39. GRB 260114A: COLIBRÍ optical upper limits
  40. GRB 260114A: TNG NIR upper limit
  41. GRB 260114A: NOT optical observations
  42. Konus-Wind detection of GRB 251230A / EP251230a
  43. GRB 260114A: SVOM/GRM observation of a short burst
  44. Swift GRB 260114A: Global MASTER-Net observations report
  45. GRB 260114A: GECAM-B observation of a short burst
  46. GRB 260114A: Mondy optical observations
  47. GRB 260114A: Fermi GBM observation
  48. GRB 260112B: GECAM-B observation
  49. GRB 260114A: GMG Optical Observation
  50. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  51. GRB 260114A: Swift detection of a short burst
  52. GRB 260114A: Fermi GBM Final Real-time Localization
  53. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  54. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  55. Swift GRB260113.43: Global MASTER-Net observations report
  56. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  57. EP260110a: TRT optical upper limits
  58. Konus-Wind detection of GRB 260101A
  59. GRB 260111A: Swift-XRT observations
  60. Swift Trigger 1439093: is probably not GRB 260113A
  61. GRB 260111A: COLIBRÍ optical afterglow candidate
  62. GRB 260111A: GECAM-B observation of a burst
  63. GRB 260111A: Fermi GBM Observation
  64. The EP-WXT trigger 01709251266 is likely a flaring star
  65. Swift Trigger 1434591 is not a GRB
  66. GRB 260111A: GOTO optical upper limits
  67. GRB 260112B: Fermi GBM Final Real-time Localization
  68. GRB 260111A: Swift ToO observations
  69. GRB 251230A: Mondy Optical Observations
  70. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  71. GRB 260112A: Fermi GBM Final Real-time Localization
  72. EP260110a: SVOM/VT optical upper limits
  73. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  74. IceCube Alert 260111A: Global MASTER-Net observations report
  75. EP260110a: Global MASTER-Net observations report
  76. Fermi GRB 260111A: Global MASTER-Net observations report
  77. GRB 260111A: Fermi GBM Final Real-time Localization
  78. Swift trigger 1436759 is not an astrophysical event
  79. EP260110a: KAIT optical upper limit
  80. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  81. EP 260110a: COLIBRÍ optical observations
  82. EP260110a: SVOM/C-GFT upper limit
  83. EP260110a: BOOTES-5/JGU optical upper limit
  84. EP260110a: Einstein Probe detection of an X-ray transient
  85. GRB 260109C: LCO optical upper limits
  86. GRB 260109C: Kilonova-Catcher optical upper limit
  87. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  88. Swift Trigger 1434591: possible GRB 260109C
  89. GRB 260109B: Fermi GBM Final Real-time Localization
  90. GRB 260102A: Swift-XRT afterglow detection
  91. GRB 260109A: Fermi GBM Final Real-time Localization
  92. GRB 260104A: Swift-BAT refined analysis
  93. GRB 260101A: Swift-BAT refined analysis
  94. Swift GRB 251230A: Global MASTER-Net OT detection
  95. Fermi GRB 260107A: Global MASTER-Net observations report
  96. GRB 260102A: AbAO optical observations
  97. GRB 260107A: Fermi GBM Final Real-time Localization
  98. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  99. The EP-WXT trigger 01709251112 is likely a flaring star
  100. Fermi GRB 260105A: Global MASTER-Net observations report

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