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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"

43599 results found.

  1. GRB 100206A: Gemini-North observations
  2. GRB 100131A: MASTER-Net optical alert observations
  3. GRB 100206A: MASTER-Net optical alert observations
  4. GRB 100206A: PAIRITEL Photometry of Host Candidate
  5. GRB 100206A - Keck/LRIS Spectroscopy
  6. GRB 100206A: NOT NIR observations
  7. GRB 100206A: WHT candidate afterglow
  8. GRB 100206A: optical observations from Southern Spain
  9. GRB 100205A: GROND upper limits
  10. GRB 100206A: Swift-XRT refined analysis
  11. GRB 100206A: Fermi GBM observation
  12. GRB 100206A: Optical limit
  13. GRB 100206A: Swift-BAT refined analysis
  14. GRB 100206A: Enhanced Swift-XRT position
  15. GRB 100206A: Pre-explosion imaging and host candidate
  16. GRB 100206A: Swift detection of a short hard burst
  17. GRB 100205A: Gemini-N + NIRI photometry
  18. GRB 100130B: Fermi GBM detection
  19. GRB 100113A: Fermi GBM detection
  20. GRB 100205A: Swift-BAT refined analysis
  21. GRB 100205A: Swift UVOT upper limits
  22. GRB 100205A: Swift XRT refined analysis
  23. GRB 100203A: Swift XRT and UVOT refined analyses
  24. GRB 100205A: Enhanced Swift-XRT position
  25. GRB 100205A Gemini-North IR afterglow candidate
  26. GRB 100205A: Gemini-South Observations
  27. GRB 100205A: Super-LOTIS early observations
  28. GRB 100131A: Suzaku WAM observation of the prompt emission
  29. GRB 100205A: NOT optical observations
  30. GRB 100205A: Swift detection of a burst
  31. GRB 100203A Detected in Ground Analysis of BAT Data
  32. Short X-ray Transient detected by MAXI/GSC
  33. GRB 100131A: Fermi GBM detection
  34. GRB 100119A: Suzaku WAM observation of the prompt emission
  35. Konus-Wind observation of GRB 100119A
  36. GRB 100122A: Fermi GBM detection
  37. GRB 100122A: MASTER-Net optical observations
  38. GRB 100116A: Suzaku WAM observation of the prompt emission
  39. GRB 100115A: Swift-XRT refined analysis
  40. GRB 100119A: Swift-BAT refined analysis
  41. GRB091109A: VLT/FORS2 spectroscopic redshift
  42. GRB 100117A: candidate optical afterglow
  43. GRB 100119A: Swift detection of a burst
  44. Konus-Wind observation of GRB 100116A
  45. GRB 100117A: Gemini North spectroscopy
  46. GRB 100117A: Fermi GBM detection
  47. GRB 100117A: Optical object inside the revised XRT error circle
  48. GRB 100117A: Swift-XRT refined analysis
  49. GRB 100117A: Gemini-North upper limit
  50. GRB 100117A: Magellan IMACS imaging
  51. GRB 100117A: Gemini South Imaging and CFHT Pre-Explosion Images
  52. GRB 100117A: Swift-BAT refined analysis
  53. GRB100117A: Possible afterglow from NOT observation
  54. GRB 100117A: Swift detection of a short hard burst
  55. GRB 100115A: Gemini-N photometry
  56. GRB 100115A: Enhanced Swift-XRT position
  57. GRB 100116A: Fermi LAT detection
  58. GRB 100115A: SARA Astrometry
  59. GRB100115A: Revision of NOT observation
  60. GRB 100116A: Fermi GBM detection
  61. NOT observation of GRB100115A localization
  62. GRB 100115A: SARA Afterglow Candidate
  63. GRB 100115A: Swift/UVOT Upper Limits
  64. GRB 100115A: Swift-XRT candidate afterglow
  65. GRB 100115A detected in ground analysis of Swift-BAT data
  66. GRB 100111A: PAIRITEL NIR Upper Limits
  67. GRB 100111A: Swift UVOT Refined Analysis
  68. GRB 100111A: Swift-BAT refined analysis
  69. GRB 100111A: Enhanced Swift-XRT position
  70. GRB100111A: Swift-XRT refined analysis
  71. GRB 100111A: Fermi GBM observation
  72. GRB 100111A: NOT optical observations
  73. GRB 100111A: Swift detection of a burst with an optical afterglow
  74. Swift/BAT Detects an Outburst from XTE J1901+014
  75. Swift Trigger #382159 is due to XTE J1752-223
  76. GRB 100103A: GROND Upper Limits
  77. GRB 100103A: Swift-XRT team refined analysis
  78. GRB 100103A - UVOT-enhanced XRT position
  79. Konus-Wind observation of GRB 100103A
  80. GRB 100103A: Correction to Swift position error
  81. GRB 100103A: Swift/XRT position
  82. GRB 100103A: a long GRB detected with INTEGRAL
  83. Swift Trigger 381591 is probably not a burst
  84. GRB 091231: GROND NIR observations
  85. Swift Trigger 381591: Uncatalogued UVOT Source
  86. GRB 091230: Swift/UVOT Observations
  87. Trigger 381591: Swift detection of a possible burst
  88. GRB 091230: Swift-XRT observation
  89. GRB 091230: GROND optical/NIR afterglow candidate
  90. GRB 091230: a long GRB detected by INTEGRAL
  91. Swift Trigger 381434 is not a GRB
  92. Trigger 381434: Swift detection of a possible burst
  93. GRB 091221 : IRSF NIR upper limit
  94. GRB 091221: Skynet/PROMPT Detections
  95. GRB 091221: Fermi GBM Observation
  96. GRB 091117: Swift-XRT late time observations
  97. GRB 091221 Swift-BAT refined analysis
  98. GRB 091221: Swift/UVOT refined analysis
  99. GRB 091221: Swift-XRT refined analysis
  100. GRB 091221: Enhanced Swift-XRT position

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