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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 detection of a burst
  2. Swift-BAT Notices back to autonomous real-time distribution
  3. GRB 070911: PAIRITEL IR Observations
  4. GRB 070911: Swift XRT refined analysis
  5. GRB 070911, Swift-BAT refined analysis
  6. GRB 070911: Swift detection of a burst
  7. IPN search for a GRB associated with TAROT transient on August 31
  8. Intense burst from SGR 1806-20 detected on September 7
  9. GRB 070809: Confirmation of optical transient
  10. Observations of possible TAROT GRB transient near IC 4779
  11. Candidate Orphan GRB Optical Transient in IC 4779
  12. GRB 070810b: Image Subtraction of Multiple Keck Observations
  13. Las Campanas observations of possible TAROT GRB transient near IC
  14. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  15. Konus-Wind observation of GRB 070824
  16. GRB 070824 - Combined SuperAGILE/IPN Localization
  17. Konus-Wind observation of very bright GRB 070821
  18. GRB 070731: Swift/UVOT Upper Limit
  19. IPN Localization of GRB 070821 (long, very bright)
  20. GRB 070805: UVOT afterglow candidate retraction
  21. GRB070810b: optical candidate
  22. GRB 070810A: ROTSE-III Refined Analysis
  23. Swift observatory off line
  24. GRB 061110A: redshift confirmed
  25. GRB 070810B : Faulkes Telescope South Observations
  26. GRB 070810A: Continued Keck Imaging
  27. GRB 070810B: Keck spectroscopy of possible host galaxies
  28. GRB070810B: Swift/UVOT Upper Limits
  29. GRB 070810B: XRT refined analysis
  30. GRB 070810B, Swift-BAT refined analysis
  31. GRB 070810: MASTER optical observation
  32. GRB 070809: Swift/UVOT Corrected Photometry
  33. Swift Alert 070810.8: MASTER optical observation
  34. Swift Trigger 287421: False trigger due to star tracker loss
  35. GRB 070810A: Swift-BAT refined analysis
  36. GRB 070810B: Xinglong TNT optical Upper Limit
  37. GRB070810B: Optical observations with KANATA
  38. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  39. GRB 070809: Swift/UVOT Upper Limits
  40. GRB 070810B: Swift detection of a short burst
  41. VLA upper limit on the short hard burst GRB 070729
  42. GRB 070810: Keck redshift and photometry
  43. No radio detection in superAGILE burst 070724B
  44. GRB 070809: Keck Imaging
  45. GRB 070810: Swift-XRT Team Refined Analysis
  46. GRB 070809: Swift-XRT refined analysis
  47. GRB 070810: enhanced Swift-XRT position
  48. GRB 070810: Swift/UVOT Optical Counterpart
  49. GRB 070810: ROTSE-III Detection of Optical Counterpart
  50. GRB 070810: Swift detection of a burst
  51. GRB 070809, Swift-BAT refined analysis
  52. GRB 070809: Optical Pre-imaging from Palomar
  53. GRB 070808: Swift/UVOT upper limits
  54. GRB 070809: ROTSE-III Optical Limits
  55. GRB 070809: Swift detection of a short burst
  56. GRB 070808 : Faulkes Telescope South Observations
  57. GCN Swift XRT update position notices and enhanced position circulars
  58. GRB 070808: Swift XRT refined analysis
  59. GRB 070808, Swift-BAT refined analysis
  60. GRB 070808: OPTIMA-Burst optical upper limit
  61. GRB 070808: Xinglong TNT optical Upper Limit
  62. GRB070808: Optical observations with KANATA
  63. GRB070808 - SDSS Pre-Burst Observations
  64. GRB 070808: ROTSE-III Optical Limits
  65. GRB 070808: Swift detection of a burst
  66. GRB061121A: PROMPT Observations
  67. GRB070805 XRT and UVOT afterglow candidate
  68. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  69. GRB070612A: Radio upper limit from GMRT
  70. GRB 070721B: correct afterglow position
  71. Swift/UVOT observations of GRB070805
  72. GRB 070805, Swift-BAT refined analysis
  73. GRB 070805: Swift XRT initial analysis.
  74. GRB 070805: Swift/UVOT initial analysis
  75. GRB 070805: Swift detection of a burst
  76. UVOT observations of SAXJ1810.8-2609
  77. Swift detection of a outburst from SAX J1810.8-2609
  78. VLA non-detection of GRB 070721B
  79. GRB 070802: REM optical observations
  80. GRB 070724B: Swift-XRT afterglow confirmation
  81. GRB 070802: Swift-XRT refined analysis
  82. GRB070802: Swift/UVOT upper limits
  83. GRB 070802: Confirmation of the optical afterglow
  84. GRB 070802, Swift-BAT refined analysis
  85. GRB 070802: VLT redshift
  86. GRB 070802: refined Swift XRT position
  87. GRB 070802: V-band detection of the candidate afterglow
  88. GRB 070802: LCO I-band candidate
  89. GRB 070802: GROND J band candidate
  90. GRB 070802: LCO optical observations
  91. GRB 070802: Swift detection of a burst
  92. GRB 070731, Swift-BAT refined analysis
  93. Konus-A observation of GRB 070729
  94. Swift/UVOT detection of GRB070714B
  95. AGILE-ACS position for the SGR 1806-20 July 27 burst
  96. GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
  97. GRB 070729: LCO optical imaging
  98. VLA upper limit on short hard burst GRB 070714B
  99. Intense burst from SGR 1806-20 detected on July 27
  100. GRB070729: Swift/UVOT upper limits

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