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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"

11099 results found.

  1. GRB 260207A: TESS Detection and Possible VLA Counterpart
  2. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  3. Fermi GRB 260305A: Global MASTER-Net observations report
  4. GRB 260305A: Fermi GBM Final Real-time Localization
  5. GRB 260303B: AstroSat CZTI detection
  6. GRB 260303B: NuSTAR detection of prompt emission
  7. Fermi GRB 260303B: Global MASTER-Net observations report
  8. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  9. GRB 260303B: Fermi GBM Final Real-time Localization
  10. GRB 251130B: TERI Gamma-ray detection
  11. GRB 260208A: TERI Gamma-ray detection
  12. GRB 260302A: Fermi GBM Final Real-time Localization
  13. GRB 260225B: SVOM/GRM observation
  14. GRB 260226A: Asiago r-band upper limit
  15. GRID detection of GRB 260223A
  16. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  17. Konus-Wind detection of GRB 260226A
  18. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  19. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  20. GRB 260226A: COLIBRÍ optical upper limits
  21. GRB 260226A: LCOGT Optical Upper Limit
  22. GRB 260226A: Glowbug gamma-ray detection
  23. GRB 260226A: NuSTAR detection of bright prompt emission
  24. GRB 260226A : GROWTH-India Telescope optical observations
  25. GRB 260226A: LAST optical upper limit
  26. GRB 260226A: Fermi GBM observation
  27. GRB 260226A: Fermi-LAT refined analysis
  28. Fermi GRB 260226A: Global MASTER-Net observations report
  29. GRB 260226A: AstroSat CZTI detection of bright long burst
  30. GRB 260226A: Fermi-LAT detection of a bright burst
  31. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  32. GRB 260226A: Fermi GBM Final Real-time Localization
  33. GRB 260225C: Fermi GBM Final Real-time Localization
  34. GRB 260223A: Fermi GBM Observation
  35. GRB 260225B: Fermi GBM Final Real-time Localization
  36. GRB 260223A: Glowbug gamma-ray detection
  37. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  38. GRB 260223A: SVOM/VT optical observation
  39. GRB 260223A: SVOM/GRM observation
  40. GRB 260223A: COLIBRÍ further optical observations and a brightening
  41. GRB 260223A: COLIBRÍ optical observations
  42. GRB 260223A: DDOTI Optical Candidate
  43. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  44. Fermi GRB 260223A: Global MASTER-Net observations report
  45. GRB 260223A: Fermi GBM Final Real-time Localization
  46. GRB 260222A: Fermi GBM Final Real-time Localization
  47. Fermi GRB 260221B: Global MASTER-Net observations report
  48. GRB 260221B: Fermi GBM Final Real-time Localization
  49. Fermi GRB 260221A: Global MASTER-Net observations report
  50. GRB 260221A: Fermi GBM Final Real-time Localization
  51. GRB 260219A: AstroSat CZTI detection
  52. GRB 260219A: GECAM-B observation of a long burst
  53. Fermi GRB 260219A: Global MASTER-Net observations report
  54. GRB 260219A: Fermi GBM Final Real-time Localization
  55. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  56. GRB 260217A: Fermi GBM Final Localization
  57. Konus-Wind detection of GRB 260212A
  58. GRB 260208A: AbAO and Terskol optical upper limits
  59. GRB 260208A: continued Mondy optical observations
  60. IPN triangulation of GRB 260212A
  61. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  62. GRB 260213A: GECAM-B observation of a short burst
  63. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  64. GRB 260216A: Fermi GBM Final Real-time Localization
  65. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  66. GRB 260211A: SVOM/VT optical counterpart
  67. GRB 260212A: AstroSat CZTI detection
  68. GRB 260212A: Fermi GBM Observation
  69. GRB 260212A: GECAM-B observation
  70. GRB 260212A: SVOM/GRM observation of a long burst
  71. GRB 260213B: Fermi GBM Final Localization
  72. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  73. GRB 260211A - SVOM/ECLAIRs refined analysis
  74. GRB 260204A: SVOM/ECLAIRs refined analysis
  75. GRB 260213A: Fermi GBM Final Localization
  76. GRB 260211A: SVOM/VT optical observation
  77. GRB 260212A: Glowbug gamma-ray detection
  78. Fermi GRB 260212A: Global MASTER-Net observations report
  79. GRB 260212A: Fermi GBM Final Real-time Localization
  80. Fermi GBM Sub-Threshold Detection of GRB 260211A
  81. Konus-Wind detection of GRB 260207B
  82. GRID detection of GRB 260207B
  83. GRB260131A/B: 3.6m DOT Optical Observations
  84. Fermi trigger No 792537871: Global MASTER-Net observations report
  85. GRB 260208A: Swift UVOT detection
  86. Konus-Wind detection of GRB 260127B
  87. Fermi GRB 260210C: Global MASTER-Net observations report
  88. GRB 260208A: LCO detection of the optical counterpart
  89. IPN triangulation of GRB 260207B (short/hard with EE)
  90. GRB 260210C: Fermi GBM Final Real-time Localization
  91. GRB 260210B: Fermi GBM Final Real-time Localization
  92. GRB 260208C: AstroSat CZTI detection
  93. GRB 260208B: refined analysis of the EP-FXT observation
  94. GRB 260207B: AstroSat CZTI detection
  95. GRB 260208C: SVOM/GRM observation
  96. GRB 260208B: AstroSat CZTI detection of a bright long burst
  97. GRB260208A: Liverpool Telescope optical follow-up observations
  98. GRB 260208A: Glowbug gamma-ray detection
  99. GRB 260208A: NuSTAR detection of prompt emission
  100. GRB 260208A: Fermi GBM Observation

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