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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"

27292 results found.

  1. GRB 090113: Swift UVOT upper limits
  2. GRB 090113: GROND Upper Limits
  3. GRB 090113: Swift-XRT refined analysis
  4. GRB 090113: Enhanced Swift-XRT position
  5. GRB 090113: Swift-BAT refined analysis
  6. GRB 090113: ROTSE-III Optical Limits
  7. GRB090113: XRT position
  8. GRB 090112B: Fermi GBM Detection
  9. GRB 090113: Swift detection of a burst
  10. GRB 090112: Fermi GBM detection
  11. GRB 090109: Fermi GBM detection
  12. GRB 090108B: Fermi GBM detection
  13. GRB 090111, Swift-BAT refined analysis
  14. GRB 090111: Swift UVOT Upper Limits
  15. GRB 090108: Fermi GBM Detection
  16. GRB 090111: Swift-XRT refined analysis
  17. GRB 090111: Enhanced Swift-XRT position
  18. GRB 090111: Swift detection of a burst
  19. GRB090107B: Fermi GBM Detection
  20. GRB 090107B: Swift XRT afterglow confirmation
  21. GRB 090107B: Swift/UVOT Observations
  22. GRB 090107B: Swift-XRT detection of possible afterglow
  23. Fermi/GBM detection of GRB 081226A
  24. Fermi/GBM detection of GRB 081225
  25. GRB 090107: Swift-BAT refined analysis
  26. GRB 090107: Swift detection of a burst
  27. GRB 081231: Fermi GBM Detection
  28. VLA radio upper limit on GRB 090102
  29. GRB 090102: GRT Optical Observation
  30. Swift triggered on the HMXB 1A 1118-61
  31. Konus-Wind observation of GRB 090102
  32. GRB 081229: Fermi GBM detection
  33. Swift UVOT observations of GRB 090102
  34. GRB 090102: Swift-BAT refined analysis
  35. GRB 090102: Swift burst of interest
  36. GRB 090102: Swift XRT refined analysis
  37. GRB 090102: Enhanced Swift-XRT position
  38. GRB 090102: TAROT Calern observatory optical light curve
  39. GRB 090102: Swift detection of a burst with an optical counterpart
  40. GRB 090102: TAROT Calern observatory optical observations
  41. GRB 081230: GROND confirmation of the afterglow
  42. GRB 081230, Swift-BAT refined analysis
  43. GRB081230: Swift-XRT refined analysis
  44. GRB 081230 Swift/UVOT Observations
  45. GRB 081230: Enhanced Swift-XRT position
  46. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  47. GRB 081230: ROTSE-III Detection of Optical Counterpart
  48. GRB 081230: Swift detection of a burst
  49. GRB 081228: GROND confirmation of the optical/NIR afterglow
  50. GRB 081226C: Fermi GBM detection
  51. GRB 081228, Swift-BAT refined analysis
  52. VLA radio detection of GRB 081221
  53. GRB 081228: Swift/UVOT Upper Limits
  54. GRB 081228: Swift-XRT Team refined analysis
  55. GRB 081228: detection by GROND
  56. GRB 081228: Enhanced Swift-XRT position
  57. GRB 081228: TAROT Calern observatory optical observations
  58. GRB 081228: Swift detection of a burst
  59. GRB 081226B: Swift XRT and UVOT upper limits
  60. GRB 081226: Swift-XRT refined analysis
  61. GRB 081226A: Swift UVOT Upper Limits
  62. GRB 081226A: Swift-BAT refined analysis
  63. GRB 081226: ROTSE-III Optical Limits
  64. GRB 081226: Swift detection of a possible short-hard burst
  65. GRB081224: LAT retraction
  66. GRB 081224: Swift-XRT observation
  67. GRB 081224: Fermi GBM Detection & LAT Localization
  68. Konus-Wind observation of GRB 081222
  69. GRB 081223: Fermi GBM detection
  70. GRB 081221: GROND observations
  71. GRB 081222:Optical afterglow observation
  72. GRB 081222: Fermi GBM observation
  73. GRB 081222: Gemini-South absorption redshift
  74. GRB081222: Swift/UVOT further observations
  75. GRB 081221: Probable host galaxy in Keck imaging
  76. GRB 081204C: Fermi GBM detection
  77. GRB 081222, Swift-BAT refined analysis
  78. GRB 081221, Swift-BAT refined analysis
  79. GRB081222 optical limit by "Pi of the Sky"
  80. GRB 081222: Swift XRT refined analysis
  81. GRB081221: Fermi GBM observation
  82. Swift/UVOT observations of GRB 081221
  83. IPN triangulation of bright GRB 081215A
  84. GRB 081221: Swift-XRT Refined Analysis
  85. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  86. GRB 081221: Gemini-N nIR imaging
  87. GRB081222, optical observation
  88. GRB081222: Swift/UVOT detection of an optical afterglow
  89. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  90. GRB 081222: Swift detection of a burst with a bright optical afterglow
  91. GRB 081221: Enhanced Swift-XRT position
  92. GRB 081221: Swift detection of a burst
  93. GRB 081217: Fermi GBM detection
  94. Modification of Swift/UVOT response to bright GRBs
  95. GRB081215A: Fermi-LAT observations
  96. GRB 081211B: Further Swift-XRT analysis
  97. GRB 081215B: Fermi GBM detection
  98. GRB 081215A: Fermi GBM detection (correction to event fluence)
  99. GRB 081215A: Fermi GBM detection
  100. GRB 081211B - possibly a short burst with extended emission

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