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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"

45719 results found.

  1. EP260116a: COLIBRÍ detection of a fading optical source
  2. GRB 251208D: SVOM/ECLAIRs refined analysis
  3. GRB 251208D: SVOM/ECLAIRs refined analysis
  4. GRB 260117A: Swift-XRT afterglow detection
  5. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  6. EP260119a: Global MASTER-Net observations report
  7. GRB 260115A: AstroSat CZTI detection
  8. EP260119a: LCO optical observations
  9. GRB 260117A: ZTSh optical upper limit
  10. EP260119a: COLIBRÍ optical counterpart candidate
  11. EP260119a: preliminary result from the EP-FXT observation
  12. GRB 260110A: SVOM detection of a burst through offline search
  13. EP260119a: EP-WXT detection of a fast X-ray transient
  14. Swift GRB260118.48: Global MASTER-Net observations report
  15. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  16. SVOM GRB260117.82: Global MASTER-Net observations report
  17. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  18. Swift trigger on the HMXB 1A 1118-61
  19. GRB 260117A: SVOM/VT optical candidate
  20. GRB 260117A: SVOM/C-GFT upper limit
  21. GRB 260117A: Swift-XRT observations
  22. GRB 260117A: Swift ToO observations
  23. GRB 260117A: SVOM detection of a long faint burst
  24. EP 260116a: COLIBRÍ optical upper limit
  25. Swift triggered on the HMXB 1A 1118-61
  26. GRB 260115A: GECAM-B observation
  27. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  28. EP260116a: Liverpool Telescope upper limits
  29. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  30. EP260116A: 1.3m DFOT optical upper limit
  31. GRB 260114A: VLT/MUSE spectroscopic observations
  32. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  33. EP260116a: Global MASTER-Net observations report
  34. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  35. EP260116a: Xinglong optical upper limit
  36. EP260116a: Einstein Probe detection of an X-ray transient
  37. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  38. IceCube Alert 260115.73: Global MASTER-Net observations report
  39. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  40. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  41. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  42. Fermi GRB 260115A: Global MASTER-Net observations report
  43. GRB 260115A: Fermi GBM Final Real-time Localization
  44. GRB260114A: STEP/T80S optical limits
  45. GRB 251222A: radio detection with the VLA
  46. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  47. Konus-Wind detection of GRB 260114A
  48. GRB 260114A: Swift-XRT refined Analysis
  49. GRB 260114A: 6 GHz VLA observations
  50. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  51. GRB 260114A : MITSuME Akeno optical upper limits
  52. GRB 260114A: COLIBRÍ optical upper limits
  53. GRB 260114A: TNG NIR upper limit
  54. GRB 260114A: NOT optical observations
  55. Konus-Wind detection of GRB 251230A / EP251230a
  56. GRB 260114A: SVOM/GRM observation of a short burst
  57. Swift GRB 260114A: Global MASTER-Net observations report
  58. GRB 260114A: GECAM-B observation of a short burst
  59. GRB 260114A: Mondy optical observations
  60. GRB 260114A: Fermi GBM observation
  61. GRB 260112B: GECAM-B observation
  62. GRB 260114A: GMG Optical Observation
  63. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  64. GRB 260114A: Swift detection of a short burst
  65. GRB 260114A: Fermi GBM Final Real-time Localization
  66. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  67. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  68. Swift GRB260113.43: Global MASTER-Net observations report
  69. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  70. EP260110a: TRT optical upper limits
  71. Konus-Wind detection of GRB 260101A
  72. GRB 260111A: Swift-XRT observations
  73. Swift Trigger 1439093: is probably not GRB 260113A
  74. GRB 260111A: COLIBRÍ optical afterglow candidate
  75. GRB 260111A: GECAM-B observation of a burst
  76. GRB 260111A: Fermi GBM Observation
  77. The EP-WXT trigger 01709251266 is likely a flaring star
  78. Swift Trigger 1434591 is not a GRB
  79. GRB 260111A: GOTO optical upper limits
  80. GRB 260112B: Fermi GBM Final Real-time Localization
  81. GRB 260111A: Swift ToO observations
  82. GRB 251230A: Mondy Optical Observations
  83. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  84. GRB 260112A: Fermi GBM Final Real-time Localization
  85. EP260110a: SVOM/VT optical upper limits
  86. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  87. IceCube Alert 260111A: Global MASTER-Net observations report
  88. EP260110a: Global MASTER-Net observations report
  89. Fermi GRB 260111A: Global MASTER-Net observations report
  90. GRB 260111A: Fermi GBM Final Real-time Localization
  91. Swift trigger 1436759 is not an astrophysical event
  92. EP260110a: KAIT optical upper limit
  93. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  94. EP 260110a: COLIBRÍ optical observations
  95. EP260110a: SVOM/C-GFT upper limit
  96. EP260110a: BOOTES-5/JGU optical upper limit
  97. EP260110a: Einstein Probe detection of an X-ray transient
  98. GRB 260109C: LCO optical upper limits
  99. GRB 260109C: Kilonova-Catcher optical upper limit
  100. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection

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