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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"
  1. GRB 070920B: NOT optical observations
  2. GRB 070920B: Swift detection of a burst
  3. GRB 070920, Swift-BAT refined analysis
  4. GRB 070920: TAROT Calern observatory optical observations
  5. GRB 070920: Swift detection of a burst
  6. SGR1806-20: Swift-BAT detection of enhanced activity
  7. GRB070917: Confirmation of optical afterglow
  8. GRB920925C: search for host galaxy
  9. GRB070917: optical observations
  10. GRB 070917: P60 Observations
  11. GRB 070917: pseudo-z= 2.40 from prompt emission spectrum
  12. Konus-Wind observation of GRB 070917
  13. Swift Status and XRT Calibration Uncertainties
  14. GRB 070917: Swift-XRT observations
  15. GRB 070917: KAIT optical limits
  16. GRB 070917: MITSuME Akeno Ic upper limit
  17. GRB 070917: R band observations
  18. GRB 070917, Swift-BAT refined analysis
  19. GRB 070917: Swift detection of a bright burst
  20. GRB 070911: Suzaku WAM observation of the prompt emission
  21. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  22. GRB 070809: The Swift evidence for the SHB nature of this burst
  23. GRB 070913: Afterglow candidate detected by TAROT La Silla observatory
  24. GRB 070913: Swift-BAT refined analysis
  25. GRB 070913: Corrected BAT position
  26. GRB 070913: SMARTS optical/IR observations
  27. GRB 070913: TAROT La Silla observatory optical observations
  28. GRB 070913: Swift detection of a burst
  29. Swift-BAT Notices back to autonomous real-time distribution
  30. GRB 070911: PAIRITEL IR Observations
  31. GRB 070911: Swift XRT refined analysis
  32. GRB 070911, Swift-BAT refined analysis
  33. GRB 070911: Swift detection of a burst
  34. IPN search for a GRB associated with TAROT transient on August 31
  35. Intense burst from SGR 1806-20 detected on September 7
  36. GRB 070809: Confirmation of optical transient
  37. Observations of possible TAROT GRB transient near IC 4779
  38. Candidate Orphan GRB Optical Transient in IC 4779
  39. GRB 070810b: Image Subtraction of Multiple Keck Observations
  40. Las Campanas observations of possible TAROT GRB transient near IC
  41. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  42. Konus-Wind observation of GRB 070824
  43. GRB 070824 - Combined SuperAGILE/IPN Localization
  44. Konus-Wind observation of very bright GRB 070821
  45. GRB 070731: Swift/UVOT Upper Limit
  46. IPN Localization of GRB 070821 (long, very bright)
  47. GRB 070805: UVOT afterglow candidate retraction
  48. GRB070810b: optical candidate
  49. GRB 070810A: ROTSE-III Refined Analysis
  50. Swift observatory off line
  51. GRB 061110A: redshift confirmed
  52. GRB 070810B : Faulkes Telescope South Observations
  53. GRB 070810A: Continued Keck Imaging
  54. GRB 070810B: Keck spectroscopy of possible host galaxies
  55. GRB070810B: Swift/UVOT Upper Limits
  56. GRB 070810B: XRT refined analysis
  57. GRB 070810B, Swift-BAT refined analysis
  58. GRB 070810: MASTER optical observation
  59. GRB 070809: Swift/UVOT Corrected Photometry
  60. Swift Alert 070810.8: MASTER optical observation
  61. Swift Trigger 287421: False trigger due to star tracker loss
  62. GRB 070810A: Swift-BAT refined analysis
  63. GRB 070810B: Xinglong TNT optical Upper Limit
  64. GRB070810B: Optical observations with KANATA
  65. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  66. GRB 070809: Swift/UVOT Upper Limits
  67. GRB 070810B: Swift detection of a short burst
  68. VLA upper limit on the short hard burst GRB 070729
  69. GRB 070810: Keck redshift and photometry
  70. No radio detection in superAGILE burst 070724B
  71. GRB 070809: Keck Imaging
  72. GRB 070810: Swift-XRT Team Refined Analysis
  73. GRB 070809: Swift-XRT refined analysis
  74. GRB 070810: enhanced Swift-XRT position
  75. GRB 070810: Swift/UVOT Optical Counterpart
  76. GRB 070810: ROTSE-III Detection of Optical Counterpart
  77. GRB 070810: Swift detection of a burst
  78. GRB 070809, Swift-BAT refined analysis
  79. GRB 070809: Optical Pre-imaging from Palomar
  80. GRB 070808: Swift/UVOT upper limits
  81. GRB 070809: ROTSE-III Optical Limits
  82. GRB 070809: Swift detection of a short burst
  83. GRB 070808 : Faulkes Telescope South Observations
  84. GCN Swift XRT update position notices and enhanced position circulars
  85. GRB 070808: Swift XRT refined analysis
  86. GRB 070808, Swift-BAT refined analysis
  87. GRB 070808: OPTIMA-Burst optical upper limit
  88. GRB 070808: Xinglong TNT optical Upper Limit
  89. GRB070808: Optical observations with KANATA
  90. GRB070808 - SDSS Pre-Burst Observations
  91. GRB 070808: ROTSE-III Optical Limits
  92. GRB 070808: Swift detection of a burst
  93. GRB061121A: PROMPT Observations
  94. GRB070805 XRT and UVOT afterglow candidate
  95. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  96. GRB070612A: Radio upper limit from GMRT
  97. GRB 070721B: correct afterglow position
  98. Swift/UVOT observations of GRB070805
  99. GRB 070805, Swift-BAT refined analysis
  100. GRB 070805: Swift XRT initial analysis.

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