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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

36354 results found.

  1. GRB 251013C: Chandra X-ray observations and jet break detection
  2. GRB 251111A: SVOM/VT optical observations with VHF data
  3. GRB 251111A: KAIT optical upper limit
  4. GRB 251111A: LCO optical observation
  5. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  6. GRB 251111A: SVOM detection of a soft burst
  7. GRB 251103B: Swift-BAT refined analysis
  8. GRB 251106A: Swift/UVOT Upper Limits
  9. GRB 251105B: Insight-HXMT/HE detection
  10. GRB 251106B: Insight-HXMT detection
  11. GRB 251105A: AstroSat CZTI detection
  12. GRB 251108A: Fermi GBM Final Localization Correction
  13. GRB 251102B: SVOM/GRM observation
  14. Fermi Gamma-ray Burst Monitor trigger 784279167/251108305 is not a GRB
  15. IPN triangulation of GRB 251105B (possible sGRB with EE)
  16. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  17. GRB 251106B: SVOM/GRM observation of a short burst
  18. GRB 251106A: Swift-XRT afterglow detection
  19. GRB 251106A: Kilonova-Catcher optical upper limit
  20. Fermi GBM Sub-Threshold Detection of GRB 251106A
  21. GRB 251106A: Swift/BAT arcminute localization of a burst
  22. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  23. GRB 251106A: MASTER optical observations
  24. GRB 251106A: SVOM detection of a burst
  25. GRB 251103B: AstroSat CZTI detection
  26. GRB 251025C: TERI Gamma-ray detection
  27. GRB 251016B: TERI Gamma-ray detection
  28. GRB 251016A: TERI Gamma-ray detection of a short burst
  29. GRB 250920C: TERI Gamma-ray detection
  30. Fermi Gamma-ray Burst Monitor trigger 784109140/251106337 is not a GRB
  31. GRB 251105A: Fermi GBM Observation
  32. GRB 251105C: Fermi GBM Final Localization Correction
  33. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  34. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  35. GRB 251105B: AstroSat CZTI detection of a short burst with extended emission
  36. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  37. Fermi GBM Sub-Threshold Detection of GRB 251105B
  38. GRB 251103B: Swift/UVOT Upper Limits
  39. GRB 251105B: SVOM/GRM observation of a possible short burst with extended emission
  40. Fermi GRB 251105A: Global MASTER-Net observations report
  41. GRB 251105A: Fermi GBM Final Real-time Localization
  42. Fermi Gamma-ray Burst Monitor trigger 783986701/251104920 is not a GRB
  43. GRB 251103B: Fermi GBM observation
  44. GRB 251104A: SVOM detection of a burst
  45. GRB 251028A: Insight-HXMT/HE detection
  46. GRB 251103A: Optical afterglow detection by ZTF’s public survey
  47. GRB 251103A: WFST optical observations
  48. EP251102a: OHP/T193 optical observations
  49. GRB 251103A: OHP/T193 optical observations
  50. GRB 251103A: Xinglong 2.16m optical detection
  51. GRB 251103A: Insight-HXMT detection
  52. GRB 251103A: KAIT optical observations
  53. GRB 251103B: Nanshan/HMT optical upper limit
  54. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  55. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  56. GRB 251103B: MITSuME Akeno optical upper limits
  57. GRB 251103B: Swift-XRT refined Analysis
  58. Fermi GRB 251103A: Global MASTER-Net observations report
  59. GRB 251103A: J-band detection with WINTER
  60. Swift GRB 251103B: Global MASTER-Net observations report
  61. GRB 251103B: GROWTH-India Telescope optical upper limits
  62. GRB 251103A: Kilonova-Catcher optical afterglow detection
  63. GRB 251103B: Enhanced Swift-XRT position
  64. GRB 251103B: Prompt enhanced Swift-XRT position
  65. GRB 251103B: Swift detection of a burst
  66. GRB 251103B: Fermi GBM Final Real-time Localization
  67. GRB 251103A: Swift/UVOT Detection
  68. GRB 251103A: Fermi GBM Observation
  69. GRB 251103A: SVOM/GRM observation
  70. GRB 251103A: Swift-XRT afterglow detection
  71. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  72. GRB 251025B: OHP/T193 optical upper limit
  73. GRB 251103A: LCO optical observation
  74. GRB 251103A: GOTO optical afterglow detection
  75. GRB 251102A: AstroSat CZTI detection
  76. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  77. GRB 251103A: NOT spectroscopic redshift z = 0.76
  78. GRB 251103A: BOOTES-2/TELMA optical afterglow
  79. GRB 251103A: LCO optical afterglow detection
  80. GRB 251103A: NOT optical afterglow candidate (duplicate submission)
  81. GRB 251103A: Fermi GBM Final Localization
  82. GRB 251103A: NOT optical afterglow candidate
  83. GRB 251103A: SVOM detection of a bright burst
  84. GRB 251102B: Fermi GBM Final Real-time Localization
  85. Fermi GRB 251102A: Global MASTER-Net observations report
  86. GRB 251102A: Fermi GBM Final Real-time Localization
  87. GRB 251031A: Fermi GBM Observation
  88. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  89. Konus-Wind detection of GRB 251028A
  90. GRB 251031A: BALROG localization (Fermi Trigger 783588065 / GRB 251031306)
  91. GRB 251031A: Fermi GBM Final Real-time Localization
  92. GRB 251025C: SVOM/GRM observation
  93. GRB 251028A: GECAM-B detection
  94. GRB 251028A: SVOM/GRM observation
  95. GRB 251028A: Fermi GBM Observation
  96. GRB 251026B: SOAR Classification of GOTO25jgl/SN2025absf as a Type Ia supernova
  97. GRB 251022A: Swift-XRT confirmation of fading
  98. GRB 251026B: LBT near-infrared observations
  99. GRB 250926B: VZLUSAT-2 detection
  100. GRB 250926A: VZLUSAT-2 detection

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