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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"

19590 results found.

  1. GRB 090520B: Fermi GBM detection
  2. GRB 090516A: Konus-Wind and Swift/BAT joint spectral analysis
  3. GRB 090518: Fermi GBM detection
  4. GRB 090520 Swift-BAT detection of a burst in ground analysis
  5. GRB 090423: Fermi GBM T90 follow-up analysis results
  6. GRB 090516: Fermi GBM observation
  7. GRB 090519: Swift-XRT refined analysis
  8. GRB 090519: GROND observation
  9. GRB 090519: Swift/UVOT Upper Limits
  10. GRB 090519, Swift-BAT refined analysis
  11. GRB 090519: Enhanced Swift-XRT position
  12. GRB 090519: FARO Chante Perdrix Observatory optical observations
  13. GRB 090519: TAROT Calern observatory optical observations
  14. GRB 090519: Swift detection of a burst
  15. GRB 090518: Swift/UVOT Upper Limits
  16. GRB 090518, Swift-BAT refined analysis
  17. GRB 090516, RIMOTS optical upper limits
  18. GRB090518 : Optical upper limit by MOA-II telescope
  19. GRB 090518: Swift-XRT refined analysis
  20. GRB 090518: Enhanced Swift-XRT position
  21. GRB 090518: Swift detection of a burst
  22. GRB 090515: Swift/BAT spectral lag results
  23. GRB 090516: Swift-BAT refined analysis
  24. GRB 090516: GROND OBSERVATIONS
  25. GRB 090516 - Zadko Telescope observations
  26. GRB 090516: Swift XRT refined analysis
  27. GRB 090516: Swift/UVOT Observations
  28. GRB 090516: Enhanced Swift-XRT position
  29. GRB 090516: Faulkes Telescope South optical afterglow
  30. GRB 090516: Swift detection of a burst
  31. GRB 090515: ROVOR Upper Limit
  32. GRB 090515: MMT/MMIRS NIR Upper Limit
  33. GRB 090515: Swift/UVOT Observations
  34. GRB 090515: Swift-XRT refined analysis
  35. GRB 090515: Enhanced Swift-XRT position
  36. GRB 090509: Fermi GBM observation
  37. GRB 090515: Swift-BAT refined spectral analysis
  38. GRB 090515: Swift-BAT refined analysis
  39. GRB 090509 - Zadko Telescope observations
  40. GRB 090515: Super-LOTIS Upper Limits
  41. GRB 090515: PAIRITEL Upper Limits
  42. GRB 090515: KAIT optical upper limits
  43. GRB 090515: ROTSE-III Optical Limits
  44. GRB 090515: Swift detection of a short burst
  45. GRB 090510: Suzaku WAM observation of the prompt emission
  46. GRB090510: VLT/FORS2 spectroscopic redshift
  47. GRB 090510: GROND observations
  48. GRB 090510: Swift/UVOT host galaxy candidates
  49. GRB 090510: Fermi-LAT follow-up analysis
  50. GRB 090509, further Swift-BAT refined analysis
  51. Konus-Wind observation of GRB 090510
  52. GRB 090510: UVOT refined analysis
  53. GRB 090510: Swift XRT refined analysis
  54. GRB 090510: Enhanced Swift-XRT position
  55. GRB 090510: NOT afterglow confirmation
  56. GRB 090510: Swift-BAT refined analysis
  57. GRB 090510: Fermi GBM detection
  58. GRB 090509: Swift-BAT refined analysis
  59. Fermi LAT detection of GRB 090510
  60. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  61. GRB 090510: Swift detection of a short hard burst
  62. GRB 090408: optical upper limit
  63. GRB 090418A: optical observation
  64. GRB 090509: GROND afterglow candidate
  65. GRB 090509: Swift detection of a burst
  66. GRB 090423: optical limit
  67. GRB 090424: optical observations
  68. GRB 090429A: ROVOR magnitude limit
  69. GRB 090426: optical observations
  70. GRB 090429D: Fermi GBM detection
  71. GRB 090429B: Swift/UVOT Upper Limits
  72. GRB 090429A: Swift/UVOT Upper Limits
  73. GRB 090429A: Swift-XRT refined analysis
  74. GRB 090429A: GROND upper limits
  75. GRB 090429B: Swift XRT refined analysis
  76. GRB 090429A: Enhanced Swift-XRT position
  77. GRB 090429B: RIMOTS optical upper limits
  78. GRB 090429B: Swift-BAT refined analysis
  79. GRB 090429A: Swift-BAT refined analysis
  80. GRB 090429B: Enhanced Swift-XRT position
  81. GRB 090429A - Correction to XRT position
  82. GRB090429B: Gemini-N infrared IR candidate
  83. GRB 090429B: GROND Observations
  84. GRB 090429B: Swift detection of a burst
  85. GRB 090429: Swift detection of a burst
  86. GRB 090424 : Multiband Optical observation from Nainital
  87. GRB 090423: CARMA mm observations
  88. GRB 090423: millimeter detection
  89. GRB 090426: Swift/BAT spectral lag results
  90. GRB 090424: Suzaku WAM observation of the prompt emission
  91. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  92. GRB090426 Swift/UVOT observations
  93. GRB 090426: Swift-BAT refined analysis
  94. GRB 090426: Swift-XRT refined analysis
  95. GRB 090423: GROND second epoch imaging and refined SED
  96. GRB 090426: Enhanced Swift-XRT position
  97. GRB 090426, RIMOTS optical upper limits
  98. GRB 090426: TNT confimation of optical counterpart
  99. GRB 090426: Swift detection of a burst with an optical counterpart
  100. GRB 090424: MASTER-Net prompt optical limit

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