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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"

38666 results found.

  1. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  2. SVOM GRB260117.82: Global MASTER-Net observations report
  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-XRT observations
  8. GRB 260117A: Swift ToO observations
  9. GRB 260117A: SVOM detection of a long faint burst
  10. EP 260116a: COLIBRÍ optical upper limit
  11. Swift triggered on the HMXB 1A 1118-61
  12. GRB 260115A: GECAM-B observation
  13. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  14. EP260116a: Liverpool Telescope upper limits
  15. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  16. EP260116A: 1.3m DFOT optical upper limit
  17. GRB 260114A: VLT/MUSE spectroscopic observations
  18. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  19. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  20. EP260116a: Einstein Probe detection of an X-ray transient
  21. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  22. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  24. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  25. GRB 260115A: Fermi GBM Final Real-time Localization
  26. GRB260114A: STEP/T80S optical limits
  27. GRB 251222A: radio detection with the VLA
  28. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  29. Konus-Wind detection of GRB 260114A
  30. GRB 260114A: Swift-XRT refined Analysis
  31. GRB 260114A: 6 GHz VLA observations
  32. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  33. GRB 260114A : MITSuME Akeno optical upper limits
  34. GRB 260114A: COLIBRÍ optical upper limits
  35. GRB 260114A: TNG NIR upper limit
  36. GRB 260114A: NOT optical observations
  37. Konus-Wind detection of GRB 251230A / EP251230a
  38. GRB 260114A: SVOM/GRM observation of a short burst
  39. GRB 260114A: GECAM-B observation of a short burst
  40. GRB 260114A: Mondy optical observations
  41. GRB 260114A: Fermi GBM observation
  42. GRB 260112B: GECAM-B observation
  43. GRB 260114A: GMG Optical Observation
  44. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  45. GRB 260114A: Swift detection of a short burst
  46. GRB 260114A: Fermi GBM Final Real-time Localization
  47. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  48. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  49. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  50. EP260110a: TRT optical upper limits
  51. Konus-Wind detection of GRB 260101A
  52. GRB 260111A: Swift-XRT observations
  53. Swift Trigger 1439093: is probably not GRB 260113A
  54. GRB 260111A: COLIBRÍ optical afterglow candidate
  55. GRB 260111A: GECAM-B observation of a burst
  56. GRB 260111A: Fermi GBM Observation
  57. The EP-WXT trigger 01709251266 is likely a flaring star
  58. Swift Trigger 1434591 is not a GRB
  59. GRB 260111A: GOTO optical upper limits
  60. GRB 260112B: Fermi GBM Final Real-time Localization
  61. GRB 260111A: Swift ToO observations
  62. GRB 251230A: Mondy Optical Observations
  63. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  64. GRB 260112A: Fermi GBM Final Real-time Localization
  65. EP260110a: SVOM/VT optical upper limits
  66. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  67. GRB 260111A: Fermi GBM Final Real-time Localization
  68. Swift trigger 1436759 is not an astrophysical event
  69. EP260110a: KAIT optical upper limit
  70. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  71. EP 260110a: COLIBRÍ optical observations
  72. EP260110a: SVOM/C-GFT upper limit
  73. EP260110a: BOOTES-5/JGU optical upper limit
  74. EP260110a: Einstein Probe detection of an X-ray transient
  75. GRB 260109C: LCO optical upper limits
  76. GRB 260109C: Kilonova-Catcher optical upper limit
  77. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  78. Swift Trigger 1434591: possible GRB 260109C
  79. GRB 260109B: Fermi GBM Final Real-time Localization
  80. GRB 260102A: Swift-XRT afterglow detection
  81. GRB 260109A: Fermi GBM Final Real-time Localization
  82. Swift GRB 251230A: Global MASTER-Net OT detection
  83. GRB 260102A: AbAO optical observations
  84. GRB 260107A: Fermi GBM Final Real-time Localization
  85. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  86. The EP-WXT trigger 01709251112 is likely a flaring star
  87. GRB 260105B: Fermi GBM Detection
  88. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  89. GRB 260105A: SVOM/GRM observation
  90. GRB 260105B: SVOM/GRM observation
  91. The EP-WXT trigger 01709251028 is likely a flaring star
  92. FRB 20251229A: COLIBRÍ optical upper limits
  93. EP260105a: SVOM/VT optical upperlimit
  94. GRB 260105B: Fermi GBM Final Real-time Localization
  95. GRB 260105A: Fermi GBM Final Real-time Localization
  96. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  97. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  98. EP260105a: LCO Optical Upper limit
  99. EP260104a: Einstein Probe detection of a fast X-ray transient
  100. GRB 260101A: COLIBRÍ optical upper limits

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