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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"

36135 results found.

  1. GRB 081226: ROTSE-III Optical Limits
  2. GRB 081226: Swift detection of a possible short-hard burst
  3. GRB 080810: optical observations
  4. GRB 081211B: optical observations
  5. GRB081224: LAT retraction
  6. GRB 081224: Swift-XRT observation
  7. GRB 081222: MITSuME optical observation
  8. GRB 081224: Fermi GBM Detection & LAT Localization
  9. GRB 080810: optical observations
  10. Konus-Wind observation of GRB 081222
  11. GRB 081223: Fermi GBM detection
  12. GRB 081221: GROND observations
  13. GRB 081222: Gemini-N confirmation of redshift z=2.77
  14. GRB 081222:Optical afterglow observation
  15. VLA radio upper limit on GRB 081222
  16. GRB 081222: Fermi GBM observation
  17. Fermi Gamma-ray Burst Monitor trigger 251687595 reclassification
  18. GRB 081222: Gemini-South absorption redshift
  19. GRB 081221: Probable host galaxy in Keck imaging
  20. GRB 081204C: Fermi GBM detection
  21. GRB 081222, Swift-BAT refined analysis
  22. GRB 081221, Swift-BAT refined analysis
  23. GRB081222 optical limit by "Pi of the Sky"
  24. Konus-Wind observation of very bright GRB 081215A
  25. GRB 081222: Swift XRT refined analysis
  26. GRB081221: Fermi GBM observation
  27. Swift/UVOT observations of GRB 081221
  28. IPN triangulation of bright GRB 081215A
  29. GRB 081221: Swift-XRT Refined Analysis
  30. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  31. GRB 081222: Faulkes Telescope South observations
  32. GRB 081221: Gemini-N nIR imaging
  33. GRB081203A: BTA observation
  34. Konus-Wind observation of GRB 081221
  35. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  36. GRB081222: REM candidate afterglow
  37. GRB 081222: Swift detection of a burst with a bright optical afterglow
  38. GRB 081221: Enhanced Swift-XRT position
  39. GRB 081221: further NOT observations
  40. GRB 081221: NOT observations
  41. GRB 081221: Swift detection of a burst
  42. GRB 081217: Fermi GBM detection
  43. GRB 081211B: Further Swift-XRT analysis
  44. GRB 081215B: Fermi GBM detection
  45. GRB 081216: Suzaku WAM observation of the prompt emission
  46. GRB 081216 : Fermi GBM observation
  47. GRB 081215A: Fermi GBM detection (correction to event fluence)
  48. GRB 081215A: Fermi GBM detection
  49. IPN localization of short hard GRB 081216
  50. GRB 081211B - possibly a short burst with extended emission
  51. GRB 081118: Zadko observations
  52. GRB 081215A: Gamma Repeater?
  53. GRB 0811215A: MASTER prompt optical observations
  54. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  55. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  56. Possible GRB 081211B: Swift/UVOT Upper Limits
  57. GRB 081213: Fermi GBM detection
  58. GRB 081210: optical observations
  59. Possible GRB 081211B - Swift-XRT analysis
  60. GRB 081207: Fermi GBM detection
  61. GRB 081209: Fermi GBM detection
  62. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  63. GRB 081007: Detection of a Supernova
  64. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  65. GRB 081210: Xinglong TNT R band Upper Limits
  66. GRB 081210, SMARTS optical/IR observations
  67. GRB 081211: Swift-BAT refined analysis
  68. GRB 081211: Swift XRT refined analysis
  69. GRB 081211: Swift/UVOT detection of an optical afterglow
  70. GRB 081211: Enhanced Swift-XRT position
  71. GRB 081210: Swift/UVOT refined analysis
  72. GRB 081211: Swift detection of a burst
  73. GRB 081210: Swift-XRT refined analysis
  74. GRB081203B: optical observations
  75. GRB 081210: Enhanced Swift-XRT position
  76. GRB 081210: Swift-BAT refined analysis
  77. GRB 081210: Swift detection of a burst with optical afterglow
  78. Konus-Wind observation of GRB 081209
  79. IPN triangulation of short hard GRB 081209
  80. GRB 081203A: optical observations
  81. GRB 081206C: Fermi GBM detection
  82. Radio observation of GRB 081121 with ATCA
  83. Radio observation of GRB 081118 with ATCA
  84. GRB 081206B: Fermi GBM detection
  85. GRB 081206: Fermi GBM detection
  86. GRB 081128: afterglow observations
  87. GRB 081203B: Suzaku WAM observation of the prompt emission
  88. GRB 081203B: Additional Gemini imaging
  89. Radio observation of GRB 081109 with ATCA
  90. Radio observation of GRB 081104 with ATCA
  91. Radio observation of GRB 081029 with ATCA
  92. Radio observation of GRB 081008 with ATCA
  93. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  94. GRB 081203B: Gemini observations
  95. GRB 081128: optical observation in CrAO
  96. GRB081203A: Optical observations at Ishigaki
  97. GRB 081128: Optical afterglow observations
  98. GRB 081204: GROND Observations
  99. GRB081203B: optical observations
  100. Radio detection of GRB 081203B with the VLA

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