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

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