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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"

11835 results found.

  1. GRB 260307B: SVOM/ECLAIRs refined analysis
  2. GRB 260208A: radio detection with the VLA
  3. GRB 260310A: Fermi GBM Final Real-time Localization
  4. GRB 260307A: Glowbug gamma-ray detection
  5. GRB 260308A: Fermi GBM Final Real-time Localization
  6. Fermi GBM Sub-Threshold Detection of GRB 260307B
  7. Fermi GRB 260307A: Global MASTER-Net observations report
  8. GRB 260307A: Fermi GBM Final Localization
  9. GRB 260207A: TESS Detection and Possible VLA Counterpart
  10. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  11. Fermi GRB 260305A: Global MASTER-Net observations report
  12. GRB 260305A: Fermi GBM Final Real-time Localization
  13. GRB 260303B: AstroSat CZTI detection
  14. GRB 260303B: NuSTAR detection of prompt emission
  15. Fermi GRB 260303B: Global MASTER-Net observations report
  16. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  17. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  18. GRB 260303B: Fermi GBM Final Real-time Localization
  19. GRB 251130B: TERI Gamma-ray detection
  20. GRB 260208A: TERI Gamma-ray detection
  21. GRB 260302A: Fermi GBM Final Real-time Localization
  22. GRB 260225B: SVOM/GRM observation
  23. GRB 260226A: Asiago r-band upper limit
  24. GRID detection of GRB 260223A
  25. IceCube cascade alert 142200_1517143 retraction
  26. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  27. Konus-Wind detection of GRB 260226A
  28. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  29. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  30. GRB 260226A: COLIBRÍ optical upper limits
  31. GRB 260226A: LCOGT Optical Upper Limit
  32. GRB 260226A: Glowbug gamma-ray detection
  33. GRB 260226A: NuSTAR detection of bright prompt emission
  34. GRB 260226A : GROWTH-India Telescope optical observations
  35. GRB 260226A: LAST optical upper limit
  36. GRB 260226A: Fermi GBM observation
  37. GRB 260226A: Fermi-LAT refined analysis
  38. Fermi GRB 260226A: Global MASTER-Net observations report
  39. GRB 260226A: AstroSat CZTI detection of bright long burst
  40. GRB 260226A: Fermi-LAT detection of a bright burst
  41. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  42. GRB 260226A: Fermi GBM Final Real-time Localization
  43. GRB 260225C: Fermi GBM Final Real-time Localization
  44. GRB 260223A: Fermi GBM Observation
  45. GRB 260225B: Fermi GBM Final Real-time Localization
  46. GRB 260223A: Glowbug gamma-ray detection
  47. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  48. GRB 260223A: SVOM/VT optical observation
  49. GRB 260223A: SVOM/GRM observation
  50. GRB 260223A: COLIBRÍ further optical observations and a brightening
  51. GRB 260223A: COLIBRÍ optical observations
  52. GRB 260223A: DDOTI Optical Candidate
  53. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  54. Fermi GRB 260223A: Global MASTER-Net observations report
  55. GRB 260223A: Fermi GBM Final Real-time Localization
  56. GRB 260222A: Fermi GBM Final Real-time Localization
  57. Fermi GRB 260221B: Global MASTER-Net observations report
  58. GRB 260221B: Fermi GBM Final Real-time Localization
  59. Fermi GRB 260221A: Global MASTER-Net observations report
  60. GRB 260221A: Fermi GBM Final Real-time Localization
  61. GRB 260219A: AstroSat CZTI detection
  62. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  63. GRB 260219A: GECAM-B observation of a long burst
  64. Fermi GRB 260219A: Global MASTER-Net observations report
  65. GRB 260219A: Fermi GBM Final Real-time Localization
  66. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  67. GRB 260217A: Fermi GBM Final Localization
  68. Konus-Wind detection of GRB 260212A
  69. GRB 260208A: AbAO and Terskol optical upper limits
  70. GRB 260208A: continued Mondy optical observations
  71. IPN triangulation of GRB 260212A
  72. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  73. GRB 260213A: GECAM-B observation of a short burst
  74. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  75. GRB 260216A: Fermi GBM Final Real-time Localization
  76. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  77. GRB 260211A: SVOM/VT optical counterpart
  78. GRB 260212A: AstroSat CZTI detection
  79. GRB 260212A: Fermi GBM Observation
  80. GRB 260212A: GECAM-B observation
  81. GRB 260212A: SVOM/GRM observation of a long burst
  82. GRB 260213B: Fermi GBM Final Localization
  83. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  84. GRB 260211A - SVOM/ECLAIRs refined analysis
  85. GRB 260204A: SVOM/ECLAIRs refined analysis
  86. GRB 260213A: Fermi GBM Final Localization
  87. GRB 260211A: SVOM/VT optical observation
  88. GRB 260212A: Glowbug gamma-ray detection
  89. Fermi GRB 260212A: Global MASTER-Net observations report
  90. GRB 260212A: Fermi GBM Final Real-time Localization
  91. Fermi GBM Sub-Threshold Detection of GRB 260211A
  92. Konus-Wind detection of GRB 260207B
  93. GRID detection of GRB 260207B
  94. GRB260131A/B: 3.6m DOT Optical Observations
  95. Fermi trigger No 792537871: Global MASTER-Net observations report
  96. GRB 260208A: Swift UVOT detection
  97. Konus-Wind detection of GRB 260127B
  98. Fermi GRB 260210C: Global MASTER-Net observations report
  99. GRB 260208A: LCO detection of the optical counterpart
  100. IPN triangulation of GRB 260207B (short/hard with EE)

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