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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 070911: Swift detection of a burst
  2. IPN search for a GRB associated with TAROT transient on August 31
  3. Intense burst from SGR 1806-20 detected on September 7
  4. GRB 070809: Confirmation of optical transient
  5. Observations of possible TAROT GRB transient near IC 4779
  6. Candidate Orphan GRB Optical Transient in IC 4779
  7. GRB 070810b: Image Subtraction of Multiple Keck Observations
  8. Las Campanas observations of possible TAROT GRB transient near IC
  9. Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
  10. Konus-Wind observation of GRB 070824
  11. GRB 070824 - Combined SuperAGILE/IPN Localization
  12. Konus-Wind observation of very bright GRB 070821
  13. GRB 070731: Swift/UVOT Upper Limit
  14. IPN Localization of GRB 070821 (long, very bright)
  15. GRB 070805: UVOT afterglow candidate retraction
  16. GRB070810b: optical candidate
  17. GRB 070810A: ROTSE-III Refined Analysis
  18. Swift observatory off line
  19. GRB 061110A: redshift confirmed
  20. GRB 070810B : Faulkes Telescope South Observations
  21. GRB 070810A: Continued Keck Imaging
  22. GRB 070810B: Keck spectroscopy of possible host galaxies
  23. GRB070810B: Swift/UVOT Upper Limits
  24. GRB 070810B: XRT refined analysis
  25. GRB 070810B, Swift-BAT refined analysis
  26. GRB 070810: MASTER optical observation
  27. GRB 070809: Swift/UVOT Corrected Photometry
  28. Swift Alert 070810.8: MASTER optical observation
  29. Swift Trigger 287421: False trigger due to star tracker loss
  30. GRB 070810A: Swift-BAT refined analysis
  31. GRB 070810B: Xinglong TNT optical Upper Limit
  32. GRB070810B: Optical observations with KANATA
  33. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  34. GRB 070809: Swift/UVOT Upper Limits
  35. GRB 070810B: Swift detection of a short burst
  36. VLA upper limit on the short hard burst GRB 070729
  37. GRB 070810: Keck redshift and photometry
  38. No radio detection in superAGILE burst 070724B
  39. GRB 070809: Keck Imaging
  40. GRB 070810: Swift-XRT Team Refined Analysis
  41. GRB 070809: Swift-XRT refined analysis
  42. GRB 070810: enhanced Swift-XRT position
  43. GRB 070810: Swift/UVOT Optical Counterpart
  44. GRB 070810: ROTSE-III Detection of Optical Counterpart
  45. GRB 070810: Swift detection of a burst
  46. GRB 070809, Swift-BAT refined analysis
  47. GRB 070809: Optical Pre-imaging from Palomar
  48. GRB 070808: Swift/UVOT upper limits
  49. GRB 070809: ROTSE-III Optical Limits
  50. GRB 070809: Swift detection of a short burst
  51. GRB 070808 : Faulkes Telescope South Observations
  52. GCN Swift XRT update position notices and enhanced position circulars
  53. GRB 070808: Swift XRT refined analysis
  54. GRB 070808, Swift-BAT refined analysis
  55. GRB 070808: OPTIMA-Burst optical upper limit
  56. GRB 070808: Xinglong TNT optical Upper Limit
  57. GRB070808: Optical observations with KANATA
  58. GRB070808 - SDSS Pre-Burst Observations
  59. GRB 070808: ROTSE-III Optical Limits
  60. GRB 070808: Swift detection of a burst
  61. GRB061121A: PROMPT Observations
  62. GRB070805 XRT and UVOT afterglow candidate
  63. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  64. GRB070612A: Radio upper limit from GMRT
  65. GRB 070721B: correct afterglow position
  66. Swift/UVOT observations of GRB070805
  67. GRB 070805, Swift-BAT refined analysis
  68. GRB 070805: Swift XRT initial analysis.
  69. GRB 070805: Swift/UVOT initial analysis
  70. GRB 070805: Swift detection of a burst
  71. UVOT observations of SAXJ1810.8-2609
  72. Swift detection of a outburst from SAX J1810.8-2609
  73. VLA non-detection of GRB 070721B
  74. GRB 070802: REM optical observations
  75. GRB 070724B: Swift-XRT afterglow confirmation
  76. GRB 070802: Swift-XRT refined analysis
  77. GRB070802: Swift/UVOT upper limits
  78. GRB 070802: Confirmation of the optical afterglow
  79. GRB 070802, Swift-BAT refined analysis
  80. GRB 070802: VLT redshift
  81. GRB 070802: refined Swift XRT position
  82. GRB 070802: V-band detection of the candidate afterglow
  83. GRB 070802: LCO I-band candidate
  84. GRB 070802: GROND J band candidate
  85. GRB 070802: LCO optical observations
  86. GRB 070802: Swift detection of a burst
  87. GRB 070731, Swift-BAT refined analysis
  88. Konus-A observation of GRB 070729
  89. Swift/UVOT detection of GRB070714B
  90. AGILE-ACS position for the SGR 1806-20 July 27 burst
  91. GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
  92. GRB 070729: LCO optical imaging
  93. VLA upper limit on short hard burst GRB 070714B
  94. Intense burst from SGR 1806-20 detected on July 27
  95. GRB070729: Swift/UVOT upper limits
  96. GRB 070729: Swift-XRT refined analysis
  97. GRB 070729, Swift-BAT refined analysis
  98. GRB 070729: Magellan NIR Observations
  99. GRB 070724B: P60 Observations
  100. GRB 070729: Swift detection of a short hard burst

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