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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. GRB090118 Swift/UVOT upper limits
  2. GRB 090118: GROND Upper Limits
  3. GRB 090118: Possible burst detection from Swift-BAT slew data
  4. GRB 090117B : Fermi GBM detection
  5. GRB 090117: confirmation of the X-ray afterglow
  6. GRB 090117C - Fermi GRB Detection
  7. GRB 090117 - Fermi GBM Observations
  8. GRB 090117: GROND Upper Limits
  9. GRB090117 Swift/UVOT upper limits
  10. GRB090117: Swift-XRT detection of a possible candidate afterglow
  11. GRB 090117 - SuperAGILE Localization of a long GRB
  12. GRB090102: MAGIC telescope GeV observation
  13. GRB 090112B: Suzaku WAM observation of the prompt emission
  14. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  15. GRB 090113: Swift UVOT upper limits
  16. GRB 090113: GROND Upper Limits
  17. GRB 090113: Swift-XRT refined analysis
  18. GRB 090113: Observations from NOT
  19. GRB 090113: Enhanced Swift-XRT position
  20. GRB 090113: Swift-BAT refined analysis
  21. GRB 090113: ROTSE-III Optical Limits
  22. GRB090113: XRT position
  23. GRB 090112B: Fermi GBM Detection
  24. GRB 090113: Swift detection of a burst
  25. GRB 090112: Fermi GBM detection
  26. GRB 090109: Fermi GBM detection
  27. GRB 090108B: Fermi GBM detection
  28. GRB 090111, Swift-BAT refined analysis
  29. GRB 090111: Swift UVOT Upper Limits
  30. GRB 090108: Fermi GBM Detection
  31. GRB 090111: Swift-XRT refined analysis
  32. GRB 090111: Enhanced Swift-XRT position
  33. GRB 090111: Swift detection of a burst
  34. GRB 090107B: Suzaku WAM observation of the prompt emission
  35. GRB090107B: Fermi GBM Detection
  36. GRB 090102: WSRT Radio Observations
  37. GRB 090107B: Swift XRT afterglow confirmation
  38. GRB 090107B: Swift/UVOT Observations
  39. GRB 090107B: Swift-XRT detection of possible afterglow
  40. GRB 090107B optical observations
  41. GRB 090107B: ROTSE-III Optical Limits
  42. GRB 090107B: a long GRB localized by INTEGRAL
  43. Fermi/GBM detection of GRB 081226A
  44. Fermi/GBM detection of GRB 081225
  45. GRB 090107: Swift-BAT refined analysis
  46. GRB 090107: Swift detection of a burst
  47. GRB 081231: Fermi GBM Detection
  48. GRB 090102: optical decay
  49. VLA radio upper limit on GRB 090102
  50. GRB 090102: GRT Optical Observation
  51. Swift triggered on the HMXB 1A 1118-61
  52. Konus-Wind observation of GRB 090102
  53. GRB 081229: Fermi GBM detection
  54. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  55. GRB 090102: P60 Imaging and P200 Spectroscopy
  56. GRB 090102 Observations from IAC80
  57. GRB 090102: GROND observations of the optical afterglow
  58. Swift UVOT observations of GRB 090102
  59. GRB 090102: Swift-BAT refined analysis
  60. GRB 090102: Swift burst of interest
  61. GRB 090102: Swift XRT refined analysis
  62. GRB 090102: NOT redshift
  63. GRB 090102: Enhanced Swift-XRT position
  64. GRB 090102: TAROT Calern observatory optical light curve
  65. GRB 090102: REM observations of a bright afterglow
  66. GRB 090102: Swift detection of a burst with an optical counterpart
  67. GRB 090102: TAROT Calern observatory optical observations
  68. GRB 081230: GROND confirmation of the afterglow
  69. GRB 081230, Swift-BAT refined analysis
  70. GRB081230: Swift-XRT refined analysis
  71. GRB 081230 Swift/UVOT Observations
  72. GRB 081230: Enhanced Swift-XRT position
  73. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  74. GRB 081230: ROTSE-III Detection of Optical Counterpart
  75. GRB 081230: Swift detection of a burst
  76. GRB 081228: GROND confirmation of the optical/NIR afterglow
  77. GRB 081226B: Fermi GBM observation
  78. GRB 081226C: Fermi GBM detection
  79. GRB 081228, Swift-BAT refined analysis
  80. VLA radio detection of GRB 081221
  81. GRB 081228: Swift/UVOT Upper Limits
  82. GRB 081228: Swift-XRT Team refined analysis
  83. GRB 081228: detection by GROND
  84. GRB 081228: Enhanced Swift-XRT position
  85. GRB 081228: TAROT Calern observatory optical observations
  86. GRB 081228: Swift detection of a burst
  87. VLA radio observation of GRB 081221
  88. GRB 081226B: Swift XRT and UVOT upper limits
  89. GRB 081224: Suzaku WAM observation of the prompt emission
  90. GRB 081226: Swift-XRT refined analysis
  91. GRB 081226A: Swift UVOT Upper Limits
  92. GRB 081226: Second epoch of Gemini-South imaging
  93. GRB 081226A: Swift-BAT refined analysis
  94. GRB 081226B: a short-hard GRB detected by INTEGRAL
  95. GRB 081226: Gemini-South spectrum of possible afterglow
  96. GRB 081226: Gemini-South imaging
  97. GRB 081226: GROND afterglow candidate
  98. GRB 081226: ROTSE-III Optical Limits
  99. GRB 081226: Swift detection of a possible short-hard burst
  100. GRB 080810: optical observations

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