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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"

36804 results found.

  1. IPN triangulation of GRB 260212A
  2. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  3. GRB 260213A: GECAM-B observation of a short burst
  4. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  5. GRB 260216A: Fermi GBM Final Real-time Localization
  6. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  7. EP260214a: Optical upper limits with Kinder observations
  8. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  9. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  10. GRB 260211A: SVOM/VT optical counterpart
  11. GRB 260212A: AstroSat CZTI detection
  12. GRB 260212A: Fermi GBM Observation
  13. GRB 260212A: GECAM-B observation
  14. EP260213a: Mondy R-band optical upper limit
  15. GRB 260212A: SVOM/GRM observation of a long burst
  16. GRB 260213B: Fermi GBM Final Localization
  17. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  18. GRB 260211A - SVOM/ECLAIRs refined analysis
  19. GRB 260204A: SVOM/ECLAIRs refined analysis
  20. GRB 260213A: Fermi GBM Final Localization
  21. GRB 260211A: EP-FXT follow-up observation
  22. GRB 260211A: SVOM/VT optical observation
  23. GRB 260212A: Glowbug gamma-ray detection
  24. GRB 260211A: GOTO optical upper limit
  25. Fermi GRB 260212A: Global MASTER-Net observations report
  26. GRB 260212A: Fermi GBM Final Real-time Localization
  27. GRB 260211A: LAST optical upper limit
  28. GRB 260210A: SVOM/GRM observation
  29. Fermi GBM Sub-Threshold Detection of GRB 260211A
  30. Konus-Wind detection of GRB 260207B
  31. GRB 260128B: SVOM/ECLAIRs refined analysis
  32. GRID detection of GRB 260207B
  33. GRB 260211A: LCO optical upper limits
  34. GRB260131A/B: 3.6m DOT Optical Observations
  35. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  36. Fermi trigger No 792537871: Global MASTER-Net observations report
  37. GRB 260211A: SVOM detection of a burst
  38. Konus-Wind detection of GRB 260209B
  39. GRB 260208A: Swift UVOT detection
  40. Konus-Wind detection of GRB 260127B
  41. Fermi GRB 260210C: Global MASTER-Net observations report
  42. GRB 260208A: LCO detection of the optical counterpart
  43. IPN triangulation of GRB 260207B (short/hard with EE)
  44. GRB 260210C: Fermi GBM Final Real-time Localization
  45. GRB 260210A: Glowbug gamma-ray detection
  46. GRB 260210B: Fermi GBM Final Real-time Localization
  47. GRB 260210A: AstroSat CZTI detection
  48. GRB 260208C: AstroSat CZTI detection
  49. GRB 260208B: refined analysis of the EP-FXT observation
  50. GRB 260207B: AstroSat CZTI detection
  51. GRB 260208C: SVOM/GRM observation
  52. GRB 260204A: Swift-XRT afterglow detection
  53. GRB 260208B: AstroSat CZTI detection of a bright long burst
  54. GRB260208A: Liverpool Telescope optical follow-up observations
  55. GRB 260208A: Glowbug gamma-ray detection
  56. GRB 260208A: NuSTAR detection of prompt emission
  57. GRB 260208A: Fermi GBM Observation
  58. Fermi GRB 260209A: Global MASTER-Net observations report
  59. GRB 260208B: Swift-XRT observations
  60. GRB 260131A/B: continued Mondy optical observations
  61. GRB 260204A: Swift/UVOT Upper Limits
  62. GRB 260208B: COLIBRÍ optical observations
  63. GRB 260208A: Mondy optical observations (duplicate submission)
  64. GRB 260208A: Mondy optical observations
  65. GRB 260208A: 1.3m DFOT optical detection
  66. GRB 260208A: COLIBRÍ optical observations
  67. GRB 260208B: EP-FXT observation
  68. GRB 260208A: NOT spectroscopic redshift z = 2.36
  69. GRB 260208A: Liverpool Telescope optical detection
  70. Fermi GRB 260208C: Global MASTER-Net observations report
  71. GRB 260208B: SVOM/VT optical candidate
  72. GRB 260208A: GECAM-B observation of a bright burst
  73. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  74. GRB 260209A: Fermi GBM Final Real-time Localization
  75. GRB 260208A: SVOM/VT optical observation
  76. Fermi GRB 260208D: Global MASTER-Net observations report
  77. GRB 260208D: Fermi GBM Final Real-time Localization
  78. GRB 260208A: Swift-XRT observations
  79. GRB 260208B: Swift ToO observations
  80. GRB 260208B: SVOM/GRM observation of a bright burst
  81. GRB 260208B: Fermi GBM Detection
  82. LAT GRB 260208B: Global MASTER-Net observations report
  83. GRB 260208B: Fermi-LAT detection
  84. GRB 260208C: Fermi GBM Final Real-time Localization
  85. GRB 260208A: Fermi-LAT detection
  86. GRB 260207B: GECAM-B observation
  87. GRB 260208A: Swift ToO observations
  88. GRB 260208A: Fermi GBM Classification Correction
  89. GRB 260208A: GOTO detection of a potential optical counterpart (GOTO26aob)
  90. GRB 260208A : MASTER bright optical transient inside retracted Fermi error-box
  91. GRB 260208B: BALROG localization (Fermi Trigger 792237169 / GRB 260208412)
  92. GRB 260208B: Fermi GBM Final Real-time Localization
  93. Fermi GRB 260208A: Global MASTER-Net observations report
  94. Fermi Gamma-ray Burst Monitor trigger 792220053/260208214 is not a GRB
  95. GRB 260208A: Fermi GBM Final Real-time Localization
  96. GRB 260207B: Fermi GBM Detection of a Short Burst with Extended Emission
  97. GRB 260207A : MASTER optical counterpart discovery
  98. GRB 260131A/B: Mondy and Terskol optical observations
  99. Fermi GRB 260207B: Global MASTER-Net observations report
  100. GRB 260206A: Swift-XRT observations

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