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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"

45412 results found.

  1. Konus-Wind observation of GRB 081222
  2. GRB 081223: Fermi GBM detection
  3. GRB 081221: GROND observations
  4. GRB 081222: Gemini-N confirmation of redshift z=2.77
  5. GRB 081222:Optical afterglow observation
  6. VLA radio upper limit on GRB 081222
  7. GRB 081222: Fermi GBM observation
  8. Fermi Gamma-ray Burst Monitor trigger 251687595 reclassification
  9. GRB 081222: Gemini-South absorption redshift
  10. GRB081222: Swift/UVOT further observations
  11. GRB 081221: Probable host galaxy in Keck imaging
  12. GRB 081204C: Fermi GBM detection
  13. GRB 081222, Swift-BAT refined analysis
  14. GRB 081221, Swift-BAT refined analysis
  15. GRB081222 optical limit by "Pi of the Sky"
  16. Konus-Wind observation of very bright GRB 081215A
  17. GRB 081222: Swift XRT refined analysis
  18. GRB081221: Fermi GBM observation
  19. Swift/UVOT observations of GRB 081221
  20. IPN triangulation of bright GRB 081215A
  21. GRB 081221: Swift-XRT Refined Analysis
  22. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  23. GRB 081222: Faulkes Telescope South observations
  24. GRB 081221: Gemini-N nIR imaging
  25. GRB081222, optical observation
  26. GRB081222: Swift/UVOT detection of an optical afterglow
  27. GRB081203A: BTA observation
  28. Konus-Wind observation of GRB 081221
  29. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  30. GRB081222: REM candidate afterglow
  31. GRB 081222: Swift detection of a burst with a bright optical afterglow
  32. GRB 081221: Enhanced Swift-XRT position
  33. GRB 081221: further NOT observations
  34. GRB 081221: NOT observations
  35. GRB 081221: Swift detection of a burst
  36. GRB 081217: Fermi GBM detection
  37. Modification of Swift/UVOT response to bright GRBs
  38. GRB081215A: Fermi-LAT observations
  39. GRB 081211B: Further Swift-XRT analysis
  40. GRB 081215B: Fermi GBM detection
  41. GRB 081216: Suzaku WAM observation of the prompt emission
  42. GRB 081216 : Fermi GBM observation
  43. GRB 081215A: Fermi GBM detection (correction to event fluence)
  44. GRB 081215A: Fermi GBM detection
  45. IPN localization of short hard GRB 081216
  46. GRB 081211B - possibly a short burst with extended emission
  47. GRB 081118: Zadko observations
  48. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  49. GRB 0811215A: MASTER prompt optical observations
  50. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  51. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  52. Possible GRB 081211B: Swift/UVOT Upper Limits
  53. GRB 081213: Fermi GBM detection
  54. GRB 081210: optical observations
  55. Possible GRB 081211B - Swift-XRT analysis
  56. GRB 081207: Fermi GBM detection
  57. GRB 081209: Fermi GBM detection
  58. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  59. GRB 081007: Detection of a Supernova
  60. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  61. GRB 081210: Xinglong TNT R band Upper Limits
  62. GRB 081210, SMARTS optical/IR observations
  63. GRB 081211: Swift-BAT refined analysis
  64. GRB 081211: Swift XRT refined analysis
  65. GRB 081211: Swift/UVOT detection of an optical afterglow
  66. GRB 081211: Enhanced Swift-XRT position
  67. GRB 081210: Swift/UVOT refined analysis
  68. GRB 081211: Swift detection of a burst
  69. GRB 081210: Swift-XRT refined analysis
  70. GRB081203B: optical observations
  71. GRB 081210: Enhanced Swift-XRT position
  72. GRB 081210: Swift-BAT refined analysis
  73. GRB 081210: Swift detection of a burst with optical afterglow
  74. Konus-Wind observation of GRB 081209
  75. IPN triangulation of short hard GRB 081209
  76. GRB 081203A: optical observations
  77. GRB 081206C: Fermi GBM detection
  78. Radio observation of GRB 081121 with ATCA
  79. Radio observation of GRB 081118 with ATCA
  80. GRB 081206B: Fermi GBM detection
  81. GRB 081206: Fermi GBM detection
  82. GRB 081128: afterglow observations
  83. GRB 081203B: Suzaku WAM observation of the prompt emission
  84. GRB 081203B: Additional Gemini imaging
  85. Radio observation of GRB 081109 with ATCA
  86. Radio observation of GRB 081104 with ATCA
  87. Radio observation of GRB 081029 with ATCA
  88. Radio observation of GRB 081008 with ATCA
  89. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  90. GRB 081203B: Gemini observations
  91. GRB 081128: optical observation in CrAO
  92. GRB081203A: Optical observations at Ishigaki
  93. GRB 081128: Optical afterglow observations
  94. GRB 081204: GROND Observations
  95. GRB081203B: optical observations
  96. Radio detection of GRB 081203B with the VLA
  97. GRB 081204: Magellan observations
  98. GRB081203A: Radio upper limit at 15 GHz
  99. GRB 081204B: Fermi GBM detection
  100. GRB 081204: Swift/UVOT Upper Limits

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