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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"
  1. GRB 090111, Swift-BAT refined analysis
  2. GRB 090111: Swift UVOT Upper Limits
  3. GRB 090108: Fermi GBM Detection
  4. GRB 090111: Swift-XRT refined analysis
  5. GRB 090111: Enhanced Swift-XRT position
  6. GRB 090111: Swift detection of a burst
  7. GRB 090107B: Suzaku WAM observation of the prompt emission
  8. GRB090107B: Fermi GBM Detection
  9. GRB 090102: WSRT Radio Observations
  10. GRB 090107B: Swift XRT afterglow confirmation
  11. GRB 090107B: Swift/UVOT Observations
  12. GRB 090107B: Swift-XRT detection of possible afterglow
  13. GRB 090107B optical observations
  14. GRB 090107B: ROTSE-III Optical Limits
  15. GRB 090107B: a long GRB localized by INTEGRAL
  16. Fermi/GBM detection of GRB 081226A
  17. Fermi/GBM detection of GRB 081225
  18. GRB 090107: Swift-BAT refined analysis
  19. GRB 090107: Swift detection of a burst
  20. GRB 081231: Fermi GBM Detection
  21. GRB 090102: optical decay
  22. VLA radio upper limit on GRB 090102
  23. GRB 090102: GRT Optical Observation
  24. Swift triggered on the HMXB 1A 1118-61
  25. Konus-Wind observation of GRB 090102
  26. GRB 081229: Fermi GBM detection
  27. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  28. GRB 090102: P60 Imaging and P200 Spectroscopy
  29. GRB 090102 Observations from IAC80
  30. GRB 090102: GROND observations of the optical afterglow
  31. Swift UVOT observations of GRB 090102
  32. GRB 090102: Swift-BAT refined analysis
  33. GRB 090102: Swift burst of interest
  34. GRB 090102: Swift XRT refined analysis
  35. GRB 090102: NOT redshift
  36. GRB 090102: Enhanced Swift-XRT position
  37. GRB 090102: TAROT Calern observatory optical light curve
  38. GRB 090102: REM observations of a bright afterglow
  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 081226B: Fermi GBM observation
  51. GRB 081226C: Fermi GBM detection
  52. GRB 081228, Swift-BAT refined analysis
  53. VLA radio detection of GRB 081221
  54. GRB 081228: Swift/UVOT Upper Limits
  55. GRB 081228: Swift-XRT Team refined analysis
  56. GRB 081228: detection by GROND
  57. GRB 081228: Enhanced Swift-XRT position
  58. GRB 081228: TAROT Calern observatory optical observations
  59. GRB 081228: Swift detection of a burst
  60. VLA radio observation of GRB 081221
  61. GRB 081226B: Swift XRT and UVOT upper limits
  62. GRB 081224: Suzaku WAM observation of the prompt emission
  63. GRB 081226: Swift-XRT refined analysis
  64. GRB 081226A: Swift UVOT Upper Limits
  65. GRB 081226: Second epoch of Gemini-South imaging
  66. GRB 081226A: Swift-BAT refined analysis
  67. GRB 081226B: a short-hard GRB detected by INTEGRAL
  68. GRB 081226: Gemini-South spectrum of possible afterglow
  69. GRB 081226: Gemini-South imaging
  70. GRB 081226: GROND afterglow candidate
  71. GRB 081226: ROTSE-III Optical Limits
  72. GRB 081226: Swift detection of a possible short-hard burst
  73. GRB 080810: optical observations
  74. GRB 081211B: optical observations
  75. GRB081224: LAT retraction
  76. GRB 081224: Swift-XRT observation
  77. GRB 081222: MITSuME optical observation
  78. GRB 081224: Fermi GBM Detection & LAT Localization
  79. GRB 080810: optical observations
  80. Konus-Wind observation of GRB 081222
  81. GRB 081223: Fermi GBM detection
  82. GRB 081221: GROND observations
  83. GRB 081222: Gemini-N confirmation of redshift z=2.77
  84. GRB 081222:Optical afterglow observation
  85. VLA radio upper limit on GRB 081222
  86. GRB 081222: Fermi GBM observation
  87. Fermi Gamma-ray Burst Monitor trigger 251687595 reclassification
  88. GRB 081222: Gemini-South absorption redshift
  89. GRB081222: Swift/UVOT further observations
  90. GRB 081221: Probable host galaxy in Keck imaging
  91. GRB 081204C: Fermi GBM detection
  92. GRB 081222, Swift-BAT refined analysis
  93. GRB 081221, Swift-BAT refined analysis
  94. GRB081222 optical limit by "Pi of the Sky"
  95. Konus-Wind observation of very bright GRB 081215A
  96. GRB 081222: Swift XRT refined analysis
  97. GRB081221: Fermi GBM observation
  98. Swift/UVOT observations of GRB 081221
  99. IPN triangulation of bright GRB 081215A
  100. GRB 081221: Swift-XRT Refined Analysis

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