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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. Swift Status and XRT Calibration Uncertainties
  2. GRB 070917: Swift-XRT observations
  3. GRB 070917: KAIT optical limits
  4. GRB 070917: MITSuME Akeno Ic upper limit
  5. GRB 070917: R band observations
  6. GRB 070917, Swift-BAT refined analysis
  7. GRB 070917: Swift detection of a bright burst
  8. GRB 070911: Suzaku WAM observation of the prompt emission
  9. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  10. GRB 070809: The Swift evidence for the SHB nature of this burst
  11. GRB 070913: Afterglow candidate detected by TAROT La Silla observatory
  12. GRB 070913: Swift-BAT refined analysis
  13. GRB 070913: Corrected BAT position
  14. GRB 070913: SMARTS optical/IR observations
  15. GRB 070913: TAROT La Silla observatory optical observations
  16. GRB 070913: Swift detection of a burst
  17. Swift-BAT Notices back to autonomous real-time distribution
  18. GRB 070911: PAIRITEL IR Observations
  19. GRB 070911: Swift XRT refined analysis
  20. GRB 070911, Swift-BAT refined analysis
  21. GRB 070911: Swift detection of a burst
  22. IPN search for a GRB associated with TAROT transient on August 31
  23. Intense burst from SGR 1806-20 detected on September 7
  24. GRB 070809: Confirmation of optical transient
  25. Observations of possible TAROT GRB transient near IC 4779
  26. Candidate Orphan GRB Optical Transient in IC 4779
  27. GRB 070810b: Image Subtraction of Multiple Keck Observations
  28. Las Campanas observations of possible TAROT GRB transient near IC
  29. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  30. Konus-Wind observation of GRB 070824
  31. GRB 070824 - Combined SuperAGILE/IPN Localization
  32. Konus-Wind observation of very bright GRB 070821
  33. GRB 070731: Swift/UVOT Upper Limit
  34. IPN Localization of GRB 070821 (long, very bright)
  35. GRB 070805: UVOT afterglow candidate retraction
  36. GRB070810b: optical candidate
  37. GRB 070810A: ROTSE-III Refined Analysis
  38. Swift observatory off line
  39. GRB 061110A: redshift confirmed
  40. GRB 070810B : Faulkes Telescope South Observations
  41. GRB 070810A: Continued Keck Imaging
  42. GRB 070810B: Keck spectroscopy of possible host galaxies
  43. GRB070810B: Swift/UVOT Upper Limits
  44. GRB 070810B: XRT refined analysis
  45. GRB 070810B, Swift-BAT refined analysis
  46. GRB 070810: MASTER optical observation
  47. GRB 070809: Swift/UVOT Corrected Photometry
  48. Swift Alert 070810.8: MASTER optical observation
  49. Swift Trigger 287421: False trigger due to star tracker loss
  50. GRB 070810A: Swift-BAT refined analysis
  51. GRB 070810B: Xinglong TNT optical Upper Limit
  52. GRB070810B: Optical observations with KANATA
  53. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  54. GRB 070809: Swift/UVOT Upper Limits
  55. GRB 070810B: Swift detection of a short burst
  56. VLA upper limit on the short hard burst GRB 070729
  57. GRB 070810: Keck redshift and photometry
  58. No radio detection in superAGILE burst 070724B
  59. GRB 070809: Keck Imaging
  60. GRB 070810: Swift-XRT Team Refined Analysis
  61. GRB 070809: Swift-XRT refined analysis
  62. GRB 070810: enhanced Swift-XRT position
  63. GRB 070810: Swift/UVOT Optical Counterpart
  64. GRB 070810: ROTSE-III Detection of Optical Counterpart
  65. GRB 070810: Swift detection of a burst
  66. GRB 070809, Swift-BAT refined analysis
  67. GRB 070809: Optical Pre-imaging from Palomar
  68. GRB 070808: Swift/UVOT upper limits
  69. GRB 070809: ROTSE-III Optical Limits
  70. GRB 070809: Swift detection of a short burst
  71. GRB 070808 : Faulkes Telescope South Observations
  72. GCN Swift XRT update position notices and enhanced position circulars
  73. GRB 070808: Swift XRT refined analysis
  74. GRB 070808, Swift-BAT refined analysis
  75. GRB 070808: OPTIMA-Burst optical upper limit
  76. GRB 070808: Xinglong TNT optical Upper Limit
  77. GRB070808: Optical observations with KANATA
  78. GRB070808 - SDSS Pre-Burst Observations
  79. GRB 070808: ROTSE-III Optical Limits
  80. GRB 070808: Swift detection of a burst
  81. GRB061121A: PROMPT Observations
  82. GRB070805 XRT and UVOT afterglow candidate
  83. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  84. GRB070612A: Radio upper limit from GMRT
  85. GRB 070721B: correct afterglow position
  86. Swift/UVOT observations of GRB070805
  87. GRB 070805, Swift-BAT refined analysis
  88. GRB 070805: Swift XRT initial analysis.
  89. GRB 070805: Swift/UVOT initial analysis
  90. GRB 070805: Swift detection of a burst
  91. UVOT observations of SAXJ1810.8-2609
  92. Swift detection of a outburst from SAX J1810.8-2609
  93. VLA non-detection of GRB 070721B
  94. GRB 070802: REM optical observations
  95. GRB 070724B: Swift-XRT afterglow confirmation
  96. GRB 070802: Swift-XRT refined analysis
  97. GRB070802: Swift/UVOT upper limits
  98. GRB 070802: Confirmation of the optical afterglow
  99. GRB 070802, Swift-BAT refined analysis
  100. GRB 070802: VLT redshift

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