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

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