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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"

28072 results found.

  1. GRB 100219A: XRT refined analysis
  2. GRB 100219A - Gemini South Spectroscopy
  3. GRB 100216A: Swift/UVOT Observations
  4. GRB 100219A: VLT/X-shooter redshift
  5. GRB100219A Akeno and Okayama MITSuME Optical Observation
  6. GRB 100219A: GROND observations
  7. GRB 100219A: NOT OA observations
  8. GRB 100219A: Enhanced Swift-XRT position
  9. GRB 100219A: Swift/UVOT Detection of the Optical Afterglow
  10. GRB 100216A: XRT Refined Analysis
  11. GRB 100219A: Pre-explosion imaging and host candidate
  12. GRB 100219A: Swift/UVOT Detection of a Source near the XRT Position
  13. GRB 100218A : Fermi GBM detection
  14. GRB 100219A: Swift detection of a burst
  15. GRB 100213B: GRT Optical Observation
  16. GRB 100213A: GRT Optical Observation
  17. GRB 100213B: Enhanced Swift-XRT position
  18. GRB 100213B: Gemini-N Observations
  19. GRB 100213B: Swift/UVOT Upper Limits
  20. GRB 100213A: Swift/UVOT Upper Limits
  21. GRB 100213B: PAIRITEL NIR Upper Limits
  22. GRB 100213A: Enhanced Swift-XRT position
  23. GRB 100213B: Swift XRT refined analysis
  24. GRB 100213A: SARA observations
  25. GRB 100213A: Swift XRT refined analysis
  26. GRB 100213B: NOT optical observations
  27. GRB 100213B: Swift detection of a burst
  28. GRB 100213A: Swift detection of a burst
  29. GRB 100206A: Second epoch Gemini-north observations and afterglow limits
  30. Swift/UVOT observations of GRB120212A
  31. GRB 100212A: LOAO R-band Detection/V-band Observation
  32. GRB 100212A: Fermi GBM detection
  33. GRB 100212A: Swift XRT refined analysis
  34. GRB 100212A: Enhanced Swift-XRT position
  35. GRB 100212A: candidate optical afterglow
  36. GRB 100212A: Swift detection of a burst
  37. GRB 091127: Detection of a Supernova
  38. GRB 100205A: Keck limits on an underlying host galaxy
  39. GRB 100205A: BOAO/LOAO zYJK observation
  40. GRB 100205B: Fermi GBM detection
  41. GRB 100206A: Gemini-North observations
  42. GRB 100206A: Swift/UVOT Upper Limits
  43. GRB 100206A: YNAO-GMG observations
  44. GRB 100206A - Keck/LRIS Spectroscopy
  45. GRB100206: MITSuME optical upper limits
  46. GRB 100206A: NOT NIR observations
  47. GRB 100206A: WHT candidate afterglow
  48. GRB 100206A: optical observations from Southern Spain
  49. GRB 100205A: GROND upper limits
  50. GRB 100206A: Swift-XRT refined analysis
  51. GRB 100206A: Enhanced Swift-XRT position
  52. GRB 100206A: Pre-explosion imaging and host candidate
  53. GRB 100206A: Swift detection of a short hard burst
  54. GRB100205A: CFHT z'-band observation
  55. GRB 100205A: Gemini-N + NIRI photometry
  56. GRB 100130B: Fermi GBM detection
  57. GRB 100113A: Fermi GBM detection
  58. GRB 100205A: Swift UVOT upper limits
  59. GRB 100205A: Swift XRT refined analysis
  60. GRB 100203A: Swift XRT and UVOT refined analyses
  61. GRB 100205A: Enhanced Swift-XRT position
  62. GRB 100205A Gemini-North IR afterglow candidate
  63. GRB 100205A: Gemini-South Observations
  64. GRB 100205A: Super-LOTIS early observations
  65. GRB 100205A: NOT optical observations
  66. GRB 100205A: Swift detection of a burst
  67. GRB 100203A Detected in Ground Analysis of BAT Data
  68. Short X-ray Transient detected by MAXI/GSC
  69. GRB 100131A: Fermi GBM detection
  70. GRB 100122A: Fermi GBM detection
  71. GRB 100115A: Swift-XRT refined analysis
  72. GRB091109A: VLT/FORS2 spectroscopic redshift
  73. GRB 100117A: candidate optical afterglow
  74. GRB 100119A: Swift detection of a burst
  75. GRB 100117A: Gemini North spectroscopy
  76. GRB 100117A: Fermi GBM detection
  77. Swift/UVOT refined analysis of GRB100117A
  78. GRB 100117A: Optical object inside the revised XRT error circle
  79. GRB 100117A: Swift-XRT refined analysis
  80. GRB 100117A: Gemini-North upper limit
  81. GRB 100117A: Magellan IMACS imaging
  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. GRB100115A: Revision of NOT observation
  90. GRB 100116A: Fermi GBM detection
  91. NOT observation of GRB100115A localization
  92. GRB 100115A: SARA Afterglow Candidate
  93. GRB 100115A: Swift/UVOT Upper Limits
  94. GRB 100115A: Swift-XRT candidate afterglow
  95. GRB 100111A: PAIRITEL NIR Upper Limits
  96. GRB 100111A: Swift UVOT Refined Analysis
  97. GRB 100111A: Enhanced Swift-XRT position
  98. GRB100111A: Swift-XRT refined analysis
  99. GRB 100111A: NOT optical observations
  100. GRB 100111A: Swift detection of a burst with an optical afterglow

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