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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"

11519 results found.

  1. GRB 260312B: BALROG localization (Fermi Trigger 795001611 / GRB 260312407)
  2. GRB 260312B: Fermi GBM Final Real-time Localization
  3. GRB 260310B: GECAM-B observation of a burst
  4. GRB 260311B: Fermi GBM Final Real-time Localization
  5. GRB 260131A/B: radio detection with the VLA
  6. GRB260307A: GECAM-B observation of a burst
  7. GRB 260308A: SVOM/GRM observation of a short GRB
  8. GRB 260310A: AstroSat CZTI detection of a long burst
  9. GRB 260311A: Fermi GBM Final Real-time Localization
  10. Fermi GRB 260310B: Global MASTER-Net observations report
  11. GRB 260310B: Fermi GBM Final Real-time Localization
  12. Fermi GRB 260310A: Global MASTER-Net observations report
  13. GRB 260307B: SVOM/ECLAIRs refined analysis
  14. GRB 260208A: radio detection with the VLA
  15. GRB 260310A: Fermi GBM Final Real-time Localization
  16. GRB 260307A: Glowbug gamma-ray detection
  17. GRB 260308A: Fermi GBM Final Real-time Localization
  18. Fermi GBM Sub-Threshold Detection of GRB 260307B
  19. Fermi GRB 260307A: Global MASTER-Net observations report
  20. GRB 260307A: Fermi GBM Final Localization
  21. GRB 260207A: TESS Detection and Possible VLA Counterpart
  22. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  23. Fermi GRB 260305A: Global MASTER-Net observations report
  24. GRB 260305A: Fermi GBM Final Real-time Localization
  25. GRB 260303B: AstroSat CZTI detection
  26. GRB 260303B: NuSTAR detection of prompt emission
  27. Fermi GRB 260303B: Global MASTER-Net observations report
  28. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  29. GRB 260303B: Fermi GBM Final Real-time Localization
  30. GRB 251130B: TERI Gamma-ray detection
  31. GRB 260208A: TERI Gamma-ray detection
  32. GRB 260302A: Fermi GBM Final Real-time Localization
  33. GRB 260225B: SVOM/GRM observation
  34. GRB 260226A: Asiago r-band upper limit
  35. GRID detection of GRB 260223A
  36. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  37. Konus-Wind detection of GRB 260226A
  38. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  39. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  40. GRB 260226A: COLIBRÍ optical upper limits
  41. GRB 260226A: LCOGT Optical Upper Limit
  42. GRB 260226A: Glowbug gamma-ray detection
  43. GRB 260226A: NuSTAR detection of bright prompt emission
  44. GRB 260226A : GROWTH-India Telescope optical observations
  45. GRB 260226A: LAST optical upper limit
  46. GRB 260226A: Fermi GBM observation
  47. GRB 260226A: Fermi-LAT refined analysis
  48. Fermi GRB 260226A: Global MASTER-Net observations report
  49. GRB 260226A: AstroSat CZTI detection of bright long burst
  50. GRB 260226A: Fermi-LAT detection of a bright burst
  51. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  52. GRB 260226A: Fermi GBM Final Real-time Localization
  53. GRB 260225C: Fermi GBM Final Real-time Localization
  54. GRB 260223A: Fermi GBM Observation
  55. GRB 260225B: Fermi GBM Final Real-time Localization
  56. GRB 260223A: Glowbug gamma-ray detection
  57. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  58. GRB 260223A: SVOM/VT optical observation
  59. GRB 260223A: SVOM/GRM observation
  60. GRB 260223A: COLIBRÍ further optical observations and a brightening
  61. GRB 260223A: COLIBRÍ optical observations
  62. GRB 260223A: DDOTI Optical Candidate
  63. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  64. Fermi GRB 260223A: Global MASTER-Net observations report
  65. GRB 260223A: Fermi GBM Final Real-time Localization
  66. GRB 260222A: Fermi GBM Final Real-time Localization
  67. Fermi GRB 260221B: Global MASTER-Net observations report
  68. GRB 260221B: Fermi GBM Final Real-time Localization
  69. Fermi GRB 260221A: Global MASTER-Net observations report
  70. GRB 260221A: Fermi GBM Final Real-time Localization
  71. GRB 260219A: AstroSat CZTI detection
  72. GRB 260219A: GECAM-B observation of a long burst
  73. Fermi GRB 260219A: Global MASTER-Net observations report
  74. GRB 260219A: Fermi GBM Final Real-time Localization
  75. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  76. GRB 260217A: Fermi GBM Final Localization
  77. Konus-Wind detection of GRB 260212A
  78. GRB 260208A: AbAO and Terskol optical upper limits
  79. GRB 260208A: continued Mondy optical observations
  80. IPN triangulation of GRB 260212A
  81. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  82. GRB 260213A: GECAM-B observation of a short burst
  83. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  84. GRB 260216A: Fermi GBM Final Real-time Localization
  85. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  86. GRB 260211A: SVOM/VT optical counterpart
  87. GRB 260212A: AstroSat CZTI detection
  88. GRB 260212A: Fermi GBM Observation
  89. GRB 260212A: GECAM-B observation
  90. GRB 260212A: SVOM/GRM observation of a long burst
  91. GRB 260213B: Fermi GBM Final Localization
  92. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  93. GRB 260211A - SVOM/ECLAIRs refined analysis
  94. GRB 260204A: SVOM/ECLAIRs refined analysis
  95. GRB 260213A: Fermi GBM Final Localization
  96. GRB 260211A: SVOM/VT optical observation
  97. GRB 260212A: Glowbug gamma-ray detection
  98. Fermi GRB 260212A: Global MASTER-Net observations report
  99. GRB 260212A: Fermi GBM Final Real-time Localization
  100. Fermi GBM Sub-Threshold Detection of GRB 260211A

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