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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 Trigger 287421: False trigger due to star tracker loss
  2. GRB 070810A: Swift-BAT refined analysis
  3. GRB 070810B: Xinglong TNT optical Upper Limit
  4. GRB070810B: Optical observations with KANATA
  5. A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
  6. GRB 070809: Swift/UVOT Upper Limits
  7. GRB 070810B: Swift detection of a short burst
  8. VLA upper limit on the short hard burst GRB 070729
  9. GRB 070810: Keck redshift and photometry
  10. No radio detection in superAGILE burst 070724B
  11. GRB 070809: Keck Imaging
  12. GRB 070810: Swift-XRT Team Refined Analysis
  13. GRB 070809: Swift-XRT refined analysis
  14. GRB 070810: enhanced Swift-XRT position
  15. GRB 070810: Swift/UVOT Optical Counterpart
  16. GRB 070810: ROTSE-III Detection of Optical Counterpart
  17. GRB 070810: Swift detection of a burst
  18. GRB 070809, Swift-BAT refined analysis
  19. GRB 070809: Optical Pre-imaging from Palomar
  20. GRB 070808: Swift/UVOT upper limits
  21. GRB 070809: ROTSE-III Optical Limits
  22. GRB 070809: Swift detection of a short burst
  23. GRB 070808 : Faulkes Telescope South Observations
  24. GCN Swift XRT update position notices and enhanced position circulars
  25. GRB 070808: Swift XRT refined analysis
  26. GRB 070808, Swift-BAT refined analysis
  27. GRB 070808: OPTIMA-Burst optical upper limit
  28. GRB 070808: Xinglong TNT optical Upper Limit
  29. GRB070808: Optical observations with KANATA
  30. GRB070808 - SDSS Pre-Burst Observations
  31. GRB 070808: ROTSE-III Optical Limits
  32. GRB 070808: Swift detection of a burst
  33. GRB061121A: PROMPT Observations
  34. GRB070805 XRT and UVOT afterglow candidate
  35. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  36. GRB070612A: Radio upper limit from GMRT
  37. GRB 070721B: correct afterglow position
  38. Swift/UVOT observations of GRB070805
  39. GRB 070805, Swift-BAT refined analysis
  40. GRB 070805: Swift XRT initial analysis.
  41. GRB 070805: Swift/UVOT initial analysis
  42. GRB 070805: Swift detection of a burst
  43. UVOT observations of SAXJ1810.8-2609
  44. Swift detection of a outburst from SAX J1810.8-2609
  45. VLA non-detection of GRB 070721B
  46. GRB 070802: REM optical observations
  47. GRB 070724B: Swift-XRT afterglow confirmation
  48. GRB 070802: Swift-XRT refined analysis
  49. GRB070802: Swift/UVOT upper limits
  50. GRB 070802: Confirmation of the optical afterglow
  51. GRB 070802, Swift-BAT refined analysis
  52. GRB 070802: VLT redshift
  53. GRB 070802: refined Swift XRT position
  54. GRB 070802: V-band detection of the candidate afterglow
  55. GRB 070802: LCO I-band candidate
  56. GRB 070802: GROND J band candidate
  57. GRB 070802: LCO optical observations
  58. GRB 070802: Swift detection of a burst
  59. GRB 070731, Swift-BAT refined analysis
  60. Konus-A observation of GRB 070729
  61. Swift/UVOT detection of GRB070714B
  62. AGILE-ACS position for the SGR 1806-20 July 27 burst
  63. GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
  64. GRB 070729: LCO optical imaging
  65. VLA upper limit on short hard burst GRB 070714B
  66. Intense burst from SGR 1806-20 detected on July 27
  67. GRB070729: Swift/UVOT upper limits
  68. GRB 070729: Swift-XRT refined analysis
  69. GRB 070729, Swift-BAT refined analysis
  70. GRB 070729: Magellan NIR Observations
  71. GRB 070724B: P60 Observations
  72. GRB 070729: Swift detection of a short hard burst
  73. GRB 070724B: Swift/UVOT Upper limits
  74. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  75. GRB 070724B: Swift-XRT afterglow likely candidate
  76. GRB 070721A: optical observations
  77. GRB 070724A: further VLT observations
  78. GRB 070724B: Suzaku WAM observation of the prompt emission
  79. Konus-Wind observation of GRB 070724B
  80. GRB 070724B: Analysis of AGILE gamma-ray data
  81. GRB 070724B: Swift-XRT afterglow candidates
  82. GRB 070724b: First Gamma Ray Burst Localization by SuperAGILE onboard
  83. Four radio sources in Swift-XRT error box of GRB 070724
  84. GRB 070724: optical observations
  85. GRB070724: Host galaxy redshift
  86. GRB 070724: P60 and Gemini Observations
  87. GRB 060814 - Keck host detection and redshift
  88. GRB 070724: IR observations
  89. GRB 070724: Closer association with DSS source
  90. Swift/UVOT refined analysis of GRB070724
  91. GRB 070724: Swift-XRT Team refined analysis
  92. GRB 070724: Pre-Imaging Shows a Source in the XRT Error Circle
  93. Short-Hard GRB070714B: PROMPT Observations
  94. GRB 070724, Swift-BAT refined analysis of a short burst
  95. GRB 070721B: further observations and analysis
  96. GRB 070724: Swift detection of a burst
  97. GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
  98. GRB 070714B: Keck observations
  99. GRB 070721B: optical observations and proposed redshift
  100. Swift/UVOT observations of GRB070721B optical afterglow.

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