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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"

36181 results found.

  1. GRB 100205A: NOT optical observations
  2. GRB 100205A: Swift detection of a burst
  3. GRB 100203A Detected in Ground Analysis of BAT Data
  4. Short X-ray Transient detected by MAXI/GSC
  5. GRB 100131A: Fermi GBM detection
  6. GRB 100119A: Suzaku WAM observation of the prompt emission
  7. Konus-Wind observation of GRB 100119A
  8. GRB 100122A: Fermi GBM detection
  9. GRB 100122A: MASTER-Net optical observations
  10. GRB 100116A: Suzaku WAM observation of the prompt emission
  11. GRB 100115A: Swift-XRT refined analysis
  12. GRB 100119A: Swift-BAT refined analysis
  13. GRB091109A: VLT/FORS2 spectroscopic redshift
  14. GRB 100117A: candidate optical afterglow
  15. GRB 100119A: Swift detection of a burst
  16. Konus-Wind observation of GRB 100116A
  17. GRB 100117A: Gemini North spectroscopy
  18. GRB 100117A: Fermi GBM detection
  19. Swift/UVOT refined analysis of GRB100117A
  20. GRB 100117A: Optical object inside the revised XRT error circle
  21. GRB 100117A: Swift-XRT refined analysis
  22. GRB 100117A: Gemini-North upper limit
  23. GRB 100117A: Magellan IMACS imaging
  24. GRB 100117A: Gemini South Imaging and CFHT Pre-Explosion Images
  25. GRB 100117A: Swift-BAT refined analysis
  26. GRB 100117A: Swift detection of a short hard burst
  27. GRB 100115A: Gemini-N photometry
  28. GRB 100115A: Enhanced Swift-XRT position
  29. GRB 100116A: Fermi LAT detection
  30. GRB 100115A: SARA Astrometry
  31. GRB 100116A: Fermi GBM detection
  32. NOT observation of GRB100115A localization
  33. GRB 100115A: SARA Afterglow Candidate
  34. GRB 100115A: Swift/UVOT Upper Limits
  35. GRB 100115A: Swift-XRT candidate afterglow
  36. GRB 100115A detected in ground analysis of Swift-BAT data
  37. GRB 100111A: PAIRITEL NIR Upper Limits
  38. GRB 100111A: Swift UVOT Refined Analysis
  39. GRB 100111A: Swift-BAT refined analysis
  40. GRB 100111A: Enhanced Swift-XRT position
  41. GRB100111A: Swift-XRT refined analysis
  42. GRB 100111A: Fermi GBM observation
  43. GRB 100111A: NOT optical observations
  44. GRB 100111A: Swift detection of a burst with an optical afterglow
  45. GRB 100103A: GROND Upper Limits
  46. GRB 100103A: Swift-XRT team refined analysis
  47. GRB 100103A - UVOT-enhanced XRT position
  48. Konus-Wind observation of GRB 100103A
  49. GRB 100103A: Swift/UVOT Upper Limits
  50. GRB 100103A: Correction to Swift position error
  51. GRB 100103A: Swift/XRT position
  52. GRB 100103A: a long GRB detected with INTEGRAL
  53. Swift Trigger 381591 is probably not a burst
  54. GRB 091231: GROND NIR observations
  55. GRB 091230: Swift/UVOT Observations
  56. GRB 091230: Swift-XRT observation
  57. GRB 091230: GROND optical/NIR afterglow candidate
  58. GRB 091230: a long GRB detected by INTEGRAL
  59. Swift Trigger 381434 is not a GRB
  60. Trigger 381434: Swift detection of a possible burst
  61. GRB 091221 : IRSF NIR upper limit
  62. GRB 091221: Skynet/PROMPT Detections
  63. GRB 091221: Fermi GBM Observation
  64. GRB 091117: Swift-XRT late time observations
  65. GRB 091221 Swift-BAT refined analysis
  66. GRB 091221: Swift/UVOT refined analysis
  67. GRB 091221: Swift-XRT refined analysis
  68. GRB 091221: Enhanced Swift-XRT position
  69. GRB 091221, GROND observations
  70. GRB 091221: UVOT Confirmation of an Optical Afterglow
  71. GRB 091221: ROTSE-III Detection of Optical Counterpart
  72. GRB 091221: Swift detection of a burst
  73. Swift trigger 379449 (possible GRB) is not a burst
  74. GRB 091215: Faulkes Telescope North observations
  75. Trigger 379449: Swift detection of a possible burst
  76. GRB 091208B: Xinglong TNT optical observation
  77. GRB 091208A: Suzaku WAM observation of the prompt emission
  78. GRB 091208A: GAO 150cm telescope Optical Observation
  79. Konus-Wind observation of GRB 091208A
  80. GRB 091208B: GAO 150cm telescope Optical Observation
  81. GRB 091208B: optical observations
  82. GRB 091208B: Keck HIRES redshift confirmation
  83. GRB 091208B: GROND observations
  84. GRB 091208A: Swift-XRT observations
  85. GRB 091208B: Swift-XRT refined analysis
  86. GRB091208B: Swift/UVOT refined analysis
  87. GRB 091208B: Fermi GBM observation
  88. GRB 091208B, Swift-BAT refined analysis
  89. GRB 091208A Swift-BAT refined analysis
  90. GRB 091208B: Gemini-North redshift
  91. GRB 091208B: Faulkes Telescope North and South Optical Afterglow
  92. GRB 091208A, RIMOTS optical upper limits
  93. GRB 091208B: MITSuME Akeno Optical Observation
  94. GRB 091208B: Enhanced Swift-XRT position
  95. GRB 091208B: MITSuME Okayama Optical Observation
  96. GRB 091208B, RIMOTS optical upper limits
  97. GRB 091208B: Swift detection of a burst with an optical afterglow
  98. GRB 091208B: BOOTES-3 optical afterglow
  99. GRB 091208: ROTSE-III Optical Limits
  100. GRB 091208: Swift detection of a burst

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