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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"

28076 results found.

  1. GRB 071010A: bright NIR afterglow
  2. GRB071008: optical observations
  3. GRB 071010B possible optical transient
  4. GRB 071010A: Keck/LRIS Photometry
  5. GRB 071010B: Swift detection of a burst
  6. GRB 071010: Swift-XRT observation
  7. GRB071008: Swift-XRT observation
  8. GRB 071010 REM NIR observations
  9. GRB 071010: Keck/LRIS Spectroscopy
  10. GRB 071010: TAROT La Silla observatory photometry of the afterglow
  11. GRB 071010: Rapid PROMPT Detections
  12. GRB 071010: Keck Observations of the Afterglow
  13. GRB 071010: TAROT La Silla observatory detection of the afterglow
  14. GRB 071010: Swift detection of a burst
  15. GRB 071006 Swift-BAT detection of a burst
  16. GRB071008: IAC80 observation
  17. GRB 071008: Swift detection of a burst
  18. GRB 071003: XRT refined analysis
  19. Radio detection of GRB 071003 with the VLA
  20. GRB 070810B: further XRT analysis
  21. GRB 071003: VLT spectroscopy
  22. GRB 071003: Keck spectroscopy
  23. GRB071003: Faulkes Telescope North observations
  24. GRB 071003: Possible rebrightening
  25. GRB 071003 : Lulin R-band observations
  26. GRB 071003: Swift XRT position
  27. GRB 071003: OA power-law decay indices from KAIT
  28. GRB 071003: Keck HIRES spectroscopy
  29. GRB 071003 Optical observations
  30. GRB 071003: P60 Confirmation of Optical Afterglow
  31. GRB 071003: KAIT optical afterglow observations
  32. GRB 071003: Swift detection of a bright burst
  33. GRB 071001: Swift-XRT Team refined analysis
  34. Faulkes Telescope South observations of GRB 071001
  35. GRB 071001: Swift detection of a burst
  36. VLA observation of GRB 070923
  37. Disregard the Swift-XRT Notices today
  38. GRB 070911, SMARTS optical/IR afterglow observations
  39. GRB070925: Swift-XRT Afterglow confirmation
  40. GRB 070925: Gemini South Imaging
  41. GRB070925: Swift-XRT Position
  42. Update on Swift Status
  43. GRB 070920B: ROTSE-III Early Optical Limits
  44. GRB 070920B: XRT observations
  45. GRB 070923: Swift detection of a short hard burst
  46. GRB 070917: Confirmation of the X-ray afterglow
  47. GRB 070920B: NOT optical observations
  48. GRB 070920B: Swift detection of a burst
  49. GRB 070920: Swift detection of a burst
  50. SGR1806-20: Swift-BAT detection of enhanced activity
  51. GRB070917: Confirmation of optical afterglow
  52. GRB920925C: search for host galaxy
  53. GRB070917: optical observations
  54. GRB 070917: P60 Observations
  55. Swift Status and XRT Calibration Uncertainties
  56. GRB 070917: Swift-XRT observations
  57. GRB 070917: Swift detection of a bright burst
  58. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  59. GRB 070809: The Swift evidence for the SHB nature of this burst
  60. GRB 070913: Afterglow candidate detected by TAROT La Silla observatory
  61. GRB 070913: Swift detection of a burst
  62. Swift-BAT Notices back to autonomous real-time distribution
  63. GRB 070911: PAIRITEL IR Observations
  64. GRB 070911: Swift XRT refined analysis
  65. GRB 070911: Swift detection of a burst
  66. GRB 070810b: Image Subtraction of Multiple Keck Observations
  67. GRB 070824 - Combined SuperAGILE/IPN Localization
  68. GRB 070731: Swift/UVOT Upper Limit
  69. GRB 070805: UVOT afterglow candidate retraction
  70. GRB070810b: optical candidate
  71. GRB 070810A: ROTSE-III Refined Analysis
  72. GRB 061110A: redshift confirmed
  73. GRB 070810B : Faulkes Telescope South Observations
  74. GRB 070810A: Continued Keck Imaging
  75. GRB 070810B: Keck spectroscopy of possible host galaxies
  76. GRB070810B: Swift/UVOT Upper Limits
  77. GRB 070810B: XRT refined analysis
  78. GRB 070809: Swift/UVOT Corrected Photometry
  79. GRB 070810A: Swift-BAT refined analysis
  80. GRB 070809: Swift/UVOT Upper Limits
  81. GRB 070810B: Swift detection of a short burst
  82. VLA upper limit on the short hard burst GRB 070729
  83. GRB 070810: Keck redshift and photometry
  84. No radio detection in superAGILE burst 070724B
  85. GRB 070809: Keck Imaging
  86. GRB 070810: Swift-XRT Team Refined Analysis
  87. GRB 070809: Swift-XRT refined analysis
  88. GRB 070810: enhanced Swift-XRT position
  89. GRB 070810: Swift/UVOT Optical Counterpart
  90. GRB 070810: ROTSE-III Detection of Optical Counterpart
  91. GRB 070810: Swift detection of a burst
  92. GRB 070809: Optical Pre-imaging from Palomar
  93. GRB 070808: Swift/UVOT upper limits
  94. GRB 070809: ROTSE-III Optical Limits
  95. GRB 070809: Swift detection of a short burst
  96. GRB 070808 : Faulkes Telescope South Observations
  97. GCN Swift XRT update position notices and enhanced position circulars
  98. GRB 070808: Swift XRT refined analysis
  99. GRB 070808: OPTIMA-Burst optical upper limit
  100. GRB 070808: Xinglong TNT optical Upper Limit

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