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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

37524 results found.

  1. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  2. Fermi GRB 260223A: Global MASTER-Net observations report
  3. GRB 260223A: Fermi GBM Final Real-time Localization
  4. GRB 260222A: Fermi GBM Final Real-time Localization
  5. Fermi GRB 260221B: Global MASTER-Net observations report
  6. GRB 260221B: Fermi GBM Final Real-time Localization
  7. Fermi GRB 260221A: Global MASTER-Net observations report
  8. GRB 260221A: Fermi GBM Final Real-time Localization
  9. GRB 260219A: AstroSat CZTI detection
  10. GRB 260219A: GECAM-B observation of a long burst
  11. Fermi GRB 260219A: Global MASTER-Net observations report
  12. GRB 260219A: Fermi GBM Final Real-time Localization
  13. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  14. GRB 260217A: Fermi GBM Final Localization
  15. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  16. EP260214b: Mondy optical observations
  17. EP260210a: Mondy optical upper limits
  18. Konus-Wind detection of GRB 260212A
  19. GRB 260208A: AbAO and Terskol optical upper limits
  20. GRB 260208A: continued Mondy optical observations
  21. IPN triangulation of GRB 260212A
  22. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 260213A: GECAM-B observation of a short burst
  24. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  25. GRB 260216A: Fermi GBM Final Real-time Localization
  26. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  27. EP260214a: Optical upper limits with Kinder observations
  28. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  29. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  30. GRB 260211A: SVOM/VT optical counterpart
  31. GRB 260212A: AstroSat CZTI detection
  32. GRB 260212A: Fermi GBM Observation
  33. GRB 260212A: GECAM-B observation
  34. EP260213a: Mondy R-band optical upper limit
  35. GRB 260212A: SVOM/GRM observation of a long burst
  36. GRB 260213B: Fermi GBM Final Localization
  37. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  38. GRB 260211A - SVOM/ECLAIRs refined analysis
  39. GRB 260204A: SVOM/ECLAIRs refined analysis
  40. GRB 260213A: Fermi GBM Final Localization
  41. GRB 260211A: EP-FXT follow-up observation
  42. GRB 260211A: SVOM/VT optical observation
  43. GRB 260212A: Glowbug gamma-ray detection
  44. GRB 260211A: GOTO optical upper limit
  45. Fermi GRB 260212A: Global MASTER-Net observations report
  46. GRB 260212A: Fermi GBM Final Real-time Localization
  47. GRB 260211A: LAST optical upper limit
  48. GRB 260210A: SVOM/GRM observation
  49. Fermi GBM Sub-Threshold Detection of GRB 260211A
  50. Konus-Wind detection of GRB 260207B
  51. GRB 260128B: SVOM/ECLAIRs refined analysis
  52. GRID detection of GRB 260207B
  53. GRB 260211A: LCO optical upper limits
  54. GRB260131A/B: 3.6m DOT Optical Observations
  55. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  56. Fermi trigger No 792537871: Global MASTER-Net observations report
  57. GRB 260211A: SVOM detection of a burst
  58. Konus-Wind detection of GRB 260209B
  59. GRB 260208A: Swift UVOT detection
  60. Konus-Wind detection of GRB 260127B
  61. Fermi GRB 260210C: Global MASTER-Net observations report
  62. GRB 260208A: LCO detection of the optical counterpart
  63. IPN triangulation of GRB 260207B (short/hard with EE)
  64. GRB 260210C: Fermi GBM Final Real-time Localization
  65. GRB 260210A: Glowbug gamma-ray detection
  66. GRB 260210B: Fermi GBM Final Real-time Localization
  67. GRB 260210A: AstroSat CZTI detection
  68. GRB 260208C: AstroSat CZTI detection
  69. GRB 260208B: refined analysis of the EP-FXT observation
  70. GRB 260207B: AstroSat CZTI detection
  71. GRB 260208C: SVOM/GRM observation
  72. GRB 260204A: Swift-XRT afterglow detection
  73. GRB 260208B: AstroSat CZTI detection of a bright long burst
  74. GRB260208A: Liverpool Telescope optical follow-up observations
  75. GRB 260208A: Glowbug gamma-ray detection
  76. GRB 260208A: NuSTAR detection of prompt emission
  77. GRB 260208A: Fermi GBM Observation
  78. Fermi GRB 260209A: Global MASTER-Net observations report
  79. GRB 260208B: Swift-XRT observations
  80. GRB 260131A/B: continued Mondy optical observations
  81. GRB 260204A: Swift/UVOT Upper Limits
  82. GRB 260208B: COLIBRÍ optical observations
  83. GRB 260208A: Mondy optical observations (duplicate submission)
  84. GRB 260208A: Mondy optical observations
  85. GRB 260208A: 1.3m DFOT optical detection
  86. GRB 260208A: COLIBRÍ optical observations
  87. GRB 260208B: EP-FXT observation
  88. GRB 260208A: NOT spectroscopic redshift z = 2.36
  89. GRB 260208A: Liverpool Telescope optical detection
  90. Fermi GRB 260208C: Global MASTER-Net observations report
  91. GRB 260208B: SVOM/VT optical candidate
  92. GRB 260208A: GECAM-B observation of a bright burst
  93. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  94. GRB 260209A: Fermi GBM Final Real-time Localization
  95. GRB 260208A: SVOM/VT optical observation
  96. Fermi GRB 260208D: Global MASTER-Net observations report
  97. GRB 260208D: Fermi GBM Final Real-time Localization
  98. GRB 260208A: Swift-XRT observations
  99. GRB 260208B: Swift ToO observations
  100. GRB 260208B: SVOM/GRM observation of a bright burst

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