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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"

20378 results found.

  1. GRB 100305A Optical Observations
  2. GRB 100305A: Enhanced Swift-XRT position
  3. GRB 100305A: Gemini-N OT candidate
  4. GRB 100305A: PAIRITEL NIR Upper Limits
  5. GRB 100305A: P60 Observations
  6. GRB 100305A: Swift detection of a burst
  7. GRB 100302A: Swift/UVOT Upper Limits
  8. GRB 100302A: Gemini-N OT confirmation
  9. GRB 100302A: Optical observations at Crni Vrh
  10. GRB 100302A: MASTER-Net optical alert observations
  11. GRB 1000302A : A possible afterglow candidate
  12. GRB 100302A: Enhanced Swift-XRT position
  13. GRB 100302A: Swift detection of a burst
  14. GRB 100206A: optical observations in CrAO
  15. GRB 100206A: optical observations in Terskol
  16. GRB 100213B: Mondy optical observations
  17. GRB 100219A: optical observations
  18. GRB 100225A: Fermi LAT detection
  19. GRB
  20. GRB100219A Akeno and Okayama MITSuME Optical Observation
  21. GRB 100219A: GROND observations
  22. GRB 100219A: NOT OA observations
  23. GRB 100219A: Enhanced Swift-XRT position
  24. GRB 100219A: Swift/UVOT Detection of the Optical Afterglow
  25. GRB 100216A: XRT Refined Analysis
  26. GRB 100219A: Pre-explosion imaging and host candidate
  27. GRB 100219A: Swift/UVOT Detection of a Source near the XRT Position
  28. GRB 100219A: Swift detection of a burst
  29. GRB 100216A: Keck imaging
  30. GRB 100213A: Swift-BAT lag analysis indicates probably SHB
  31. GRB 100213B: GRT Optical Observation
  32. GRB 100213A: GRT Optical Observation
  33. GRB 100213B: Enhanced Swift-XRT position
  34. GRB 100213B: Gemini-N Observations
  35. GRB 100213B: Swift/UVOT Upper Limits
  36. GRB 100213A: Swift/UVOT Upper Limits
  37. GRB 100213B: PAIRITEL NIR Upper Limits
  38. GRB 100213A: Enhanced Swift-XRT position
  39. GRB 100213A: SARA observations
  40. GRB 100213B: NOT optical observations
  41. GRB 100213B: Swift detection of a burst
  42. GRB 100213A: Swift detection of a burst
  43. Swift/UVOT observations of GRB120212A
  44. GRB 100212A: Enhanced Swift-XRT position
  45. GRB 100212A: candidate optical afterglow
  46. GRB 100212A: Swift detection of a burst
  47. GRB 091127: Detection of a Supernova
  48. GRB 100205A: Keck limits on an underlying host galaxy
  49. GRB 100206A: GROND upper limits
  50. GRB 100206A: Gemini-North observations
  51. GRB 100206A: Swift/UVOT Upper Limits
  52. GRB 100131A: MASTER-Net optical alert observations
  53. GRB 100206A: YNAO-GMG observations
  54. GRB 100206A: MASTER-Net optical alert observations
  55. GRB 100206A: PAIRITEL Photometry of Host Candidate
  56. GRB100206: MITSuME optical upper limits
  57. GRB 100206A: NOT NIR observations
  58. GRB 100206A, RIMOTS optical upper limits
  59. GRB 100205A: GROND upper limits
  60. GRB 100206A: Optical limit
  61. GRB 100206A: Enhanced Swift-XRT position
  62. GRB 100206A: Pre-explosion imaging and host candidate
  63. GRB 100206A: Swift detection of a short hard burst
  64. GRB100205A: CFHT z'-band observation
  65. GRB 100205A: Gemini-N + NIRI photometry
  66. GRB 100130B: Fermi GBM detection
  67. GRB 100113A: Fermi GBM detection
  68. GRB 100205A: Swift UVOT upper limits
  69. GRB 100203A: Swift XRT and UVOT refined analyses
  70. GRB 100205A: Enhanced Swift-XRT position
  71. GRB 100205A Gemini-North IR afterglow candidate
  72. GRB 100205A: Gemini-South Observations
  73. GRB 100205A: Super-LOTIS early observations
  74. GRB 100205A: NOT optical observations
  75. GRB 100205A: Swift detection of a burst
  76. GRB 100203A Detected in Ground Analysis of BAT Data
  77. Short X-ray Transient detected by MAXI/GSC
  78. GRB 100122A: MASTER-Net optical observations
  79. GRB 100116A: Suzaku WAM observation of the prompt emission
  80. GRB 100119A: Swift-BAT refined analysis
  81. Swift/UVOT refined analysis of GRB100117A
  82. GRB 100117A: Gemini South Imaging and CFHT Pre-Explosion Images
  83. GRB100117A: Possible afterglow from NOT observation
  84. GRB 100117A: Swift detection of a short hard burst
  85. GRB 100115A: Gemini-N photometry
  86. GRB 100115A: Enhanced Swift-XRT position
  87. GRB 100116A: Fermi LAT detection
  88. GRB 100115A: SARA Astrometry
  89. GRB 100115A: SARA Afterglow Candidate
  90. GRB 100115A: Swift/UVOT Upper Limits
  91. GRB 100115A: Swift-XRT candidate afterglow
  92. GRB 100115A detected in ground analysis of Swift-BAT data
  93. GRB 100111A: PAIRITEL NIR Upper Limits
  94. GRB 100111A: Swift UVOT Refined Analysis
  95. GRB 100111A: Enhanced Swift-XRT position
  96. GRB 100111A: NOT optical observations
  97. GRB 100111A: Swift detection of a burst with an optical afterglow
  98. Swift/BAT Detects an Outburst from XTE J1901+014
  99. GRB 100103A: GROND Upper Limits
  100. GRB 100103A - UVOT-enhanced XRT position

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