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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"

12288 results found.

  1. GRB 260223A: SVOM/VT optical observation
  2. GRB 260223A: SVOM/GRM observation
  3. GRB 260223A: COLIBRÍ further optical observations and a brightening
  4. GRB 260223A: COLIBRÍ optical observations
  5. GRB 260223A: DDOTI Optical Candidate
  6. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  7. Fermi GRB 260223A: Global MASTER-Net observations report
  8. GRB 260223A: Fermi GBM Final Real-time Localization
  9. GRB 260222A: Fermi GBM Final Real-time Localization
  10. Fermi GRB 260221B: Global MASTER-Net observations report
  11. GRB 260221B: Fermi GBM Final Real-time Localization
  12. Fermi GRB 260221A: Global MASTER-Net observations report
  13. GRB 260221A: Fermi GBM Final Real-time Localization
  14. GRB 260219A: AstroSat CZTI detection
  15. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  16. GRB 260219A: GECAM-B observation of a long burst
  17. Fermi GRB 260219A: Global MASTER-Net observations report
  18. GRB 260219A: Fermi GBM Final Real-time Localization
  19. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  20. GRB 260217A: Fermi GBM Final Localization
  21. Konus-Wind detection of GRB 260212A
  22. GRB 260208A: AbAO and Terskol optical upper limits
  23. GRB 260208A: continued Mondy optical observations
  24. IPN triangulation of GRB 260212A
  25. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  26. GRB 260213A: GECAM-B observation of a short burst
  27. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  28. GRB 260216A: Fermi GBM Final Real-time Localization
  29. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  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. GRB 260212A: SVOM/GRM observation of a long burst
  35. GRB 260213B: Fermi GBM Final Localization
  36. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  37. GRB 260211A - SVOM/ECLAIRs refined analysis
  38. GRB 260204A: SVOM/ECLAIRs refined analysis
  39. GRB 260213A: Fermi GBM Final Localization
  40. GRB 260211A: SVOM/VT optical observation
  41. GRB 260212A: Glowbug gamma-ray detection
  42. Fermi GRB 260212A: Global MASTER-Net observations report
  43. GRB 260212A: Fermi GBM Final Real-time Localization
  44. Fermi GBM Sub-Threshold Detection of GRB 260211A
  45. Konus-Wind detection of GRB 260207B
  46. GRID detection of GRB 260207B
  47. GRB260131A/B: 3.6m DOT Optical Observations
  48. Fermi trigger No 792537871: Global MASTER-Net observations report
  49. GRB 260208A: Swift UVOT detection
  50. Konus-Wind detection of GRB 260127B
  51. Fermi GRB 260210C: Global MASTER-Net observations report
  52. GRB 260208A: LCO detection of the optical counterpart
  53. IPN triangulation of GRB 260207B (short/hard with EE)
  54. GRB 260210C: Fermi GBM Final Real-time Localization
  55. GRB 260210B: Fermi GBM Final Real-time Localization
  56. GRB 260208C: AstroSat CZTI detection
  57. GRB 260208B: refined analysis of the EP-FXT observation
  58. GRB 260207B: AstroSat CZTI detection
  59. GRB 260208C: SVOM/GRM observation
  60. GRB 260208B: AstroSat CZTI detection of a bright long burst
  61. GRB260208A: Liverpool Telescope optical follow-up observations
  62. GRB 260208A: Glowbug gamma-ray detection
  63. GRB 260208A: NuSTAR detection of prompt emission
  64. GRB 260208A: Fermi GBM Observation
  65. Fermi GRB 260209A: Global MASTER-Net observations report
  66. GRB 260208B: Swift-XRT observations
  67. GRB 260131A/B: continued Mondy optical observations
  68. GRB 260208B: COLIBRÍ optical observations
  69. GRB 260208A: Mondy optical observations
  70. GRB 260208A: 1.3m DFOT optical detection
  71. GRB 260208A: COLIBRÍ optical observations
  72. GRB 260208B: EP-FXT observation
  73. GRB 260208A: NOT spectroscopic redshift z = 2.36
  74. GRB 260208A: Liverpool Telescope optical detection
  75. Fermi GRB 260208C: Global MASTER-Net observations report
  76. GRB 260208B: SVOM/VT optical candidate
  77. GRB 260208A: GECAM-B observation of a bright burst
  78. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  79. GRB 260209A: Fermi GBM Final Real-time Localization
  80. GRB 260208A: SVOM/VT optical observation
  81. Fermi GRB 260208D: Global MASTER-Net observations report
  82. GRB 260208D: Fermi GBM Final Real-time Localization
  83. GRB 260208A: Swift-XRT observations
  84. GRB 260208B: Swift ToO observations
  85. GRB 260208B: SVOM/GRM observation of a bright burst
  86. GRB 260208B: Fermi GBM Detection
  87. GRB 260208B: Fermi-LAT detection
  88. GRB 260208C: Fermi GBM Final Real-time Localization
  89. GRB 260208A: Fermi-LAT detection
  90. GRB 260207B: GECAM-B observation
  91. GRB 260208A: Swift ToO observations
  92. GRB 260208A: Fermi GBM Classification Correction
  93. GRB 260208A: GOTO detection of a potential optical counterpart (GOTO26aob)
  94. GRB 260208A : MASTER bright optical transient inside retracted Fermi error-box
  95. GRB 260208B: BALROG localization (Fermi Trigger 792237169 / GRB 260208412)
  96. GRB 260208B: Fermi GBM Final Real-time Localization
  97. Fermi GRB 260208A: Global MASTER-Net observations report
  98. Fermi Gamma-ray Burst Monitor trigger 792220053/260208214 is not a GRB
  99. GRB 260208A: Fermi GBM Final Real-time Localization
  100. GRB 260207B: Fermi GBM Detection of a Short Burst with Extended Emission

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