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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"

19543 results found.

  1. GRB 100206A: GROND upper limits
  2. GRB 100206A: Gemini-North observations
  3. GRB 100206A: Swift/UVOT Upper Limits
  4. GRB 100131A: MASTER-Net optical alert observations
  5. GRB 100206A: YNAO-GMG observations
  6. GRB 100206A: MASTER-Net optical alert observations
  7. GRB 100206A: PAIRITEL Photometry of Host Candidate
  8. GRB100206: MITSuME optical upper limits
  9. GRB 100206A: NOT NIR observations
  10. GRB 100206A, RIMOTS optical upper limits
  11. GRB 100205A: GROND upper limits
  12. GRB 100206A: Fermi GBM observation
  13. GRB 100206A: Optical limit
  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. GRB100205A: CFHT z'-band observation
  18. GRB 100205A: Gemini-N + NIRI photometry
  19. GRB 100130B: Fermi GBM detection
  20. GRB 100113A: Fermi GBM detection
  21. GRB 100205A: Swift-BAT refined analysis
  22. GRB 100205A: Swift UVOT upper limits
  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 100205A: NOT optical observations
  29. GRB 100205A: Swift detection of a burst
  30. GRB 100131A: Fermi GBM detection
  31. GRB 100122A: Fermi GBM detection
  32. GRB 100122A: MASTER-Net optical observations
  33. GRB 100115A: Swift-XRT refined analysis
  34. GRB 100117A: Gemini North spectroscopy
  35. GRB 100117A: Fermi GBM detection
  36. Swift/UVOT refined analysis of GRB100117A
  37. GRB 100117A: Gemini-North upper limit
  38. GRB 100117A: Gemini South Imaging and CFHT Pre-Explosion Images
  39. GRB 100117A: Swift-BAT refined analysis
  40. GRB100117A: Possible afterglow from NOT observation
  41. GRB 100117A: Swift detection of a short hard burst
  42. GRB 100115A: Gemini-N photometry
  43. GRB 100115A: Enhanced Swift-XRT position
  44. GRB 100116A: Fermi LAT detection
  45. GRB 100115A: SARA Astrometry
  46. GRB 100115A: SARA Afterglow Candidate
  47. GRB 100115A: Swift/UVOT Upper Limits
  48. GRB 100115A: Swift-XRT candidate afterglow
  49. GRB 100111A: PAIRITEL NIR Upper Limits
  50. GRB 100111A: Swift UVOT Refined Analysis
  51. GRB 100111A: Enhanced Swift-XRT position
  52. GRB 100111A: Fermi GBM observation
  53. GRB 100111A: NOT optical observations
  54. GRB 100111A: Swift detection of a burst with an optical afterglow
  55. Swift/BAT Detects an Outburst from XTE J1901+014
  56. GRB 100103A: GROND Upper Limits
  57. GRB 100103A: Swift-XRT team refined analysis
  58. GRB 100103A - UVOT-enhanced XRT position
  59. GRB 100103A: Swift/XRT position
  60. GRB 091231: GROND NIR observations
  61. Swift Trigger 381591: Uncatalogued UVOT Source
  62. GRB 091230: Swift/UVOT Observations
  63. Trigger 381591: Swift detection of a possible burst
  64. GRB 091230: Swift-XRT observation
  65. GRB 091230: GROND optical/NIR afterglow candidate
  66. Swift Trigger 381434 is not a GRB
  67. Trigger 381434: Swift detection of a possible burst
  68. GRB 091221: Fermi GBM Observation
  69. GRB 091117: Swift-XRT late time observations
  70. GRB 091221: Swift/UVOT refined analysis
  71. GRB 091221: Enhanced Swift-XRT position
  72. GRB 091221, GROND observations
  73. GRB 091221: UVOT Confirmation of an Optical Afterglow
  74. GRB 091221: Swift detection of a burst
  75. GRB 091215: Faulkes Telescope North observations
  76. Trigger 379449: Swift detection of a possible burst
  77. GRB 091208A: GAO 150cm telescope Optical Observation
  78. GRB 091208B: GAO 150cm telescope Optical Observation
  79. GRB091208A: Swift/UVOT refined analysis
  80. GRB 091208B: optical observations
  81. GRB 091208B: Keck HIRES redshift confirmation
  82. GRB 091208B: GROND observations
  83. GRB 091208A: Swift-XRT observations
  84. GRB091208B: NOT optical observations
  85. GRB 091208B: Fermi GBM observation
  86. GRB 091208B, Swift-BAT refined analysis
  87. GRB 091208B: Gemini-North redshift
  88. GRB 091208A, RIMOTS optical upper limits
  89. GRB 091208B: MITSuME Akeno Optical Observation
  90. GRB 091208B: Enhanced Swift-XRT position
  91. GRB 091208B: MITSuME Okayama Optical Observation
  92. GRB 091208B, RIMOTS optical upper limits
  93. GRB 091208B: Swift detection of a burst with an optical afterglow
  94. GRB 091208B: BOOTES-3 optical afterglow
  95. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  96. GRB 091109A: GROND confirmation of redshift z = 3.5
  97. GRB 091127, SMARTS optical/IR afterglow observations
  98. GRB 091202: Swift/UVOT Upper Limits
  99. GRB 091202 - UVOT-enhanced XRT position
  100. GRB 091127: Zadko Telescope Observations

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