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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 070808 : Faulkes Telescope South Observations
  2. GCN Swift XRT update position notices and enhanced position circulars
  3. GRB 070808: Swift XRT refined analysis
  4. GRB 070808, Swift-BAT refined analysis
  5. GRB 070808: OPTIMA-Burst optical upper limit
  6. GRB 070808: Xinglong TNT optical Upper Limit
  7. GRB070808: Optical observations with KANATA
  8. GRB070808 - SDSS Pre-Burst Observations
  9. GRB 070808: ROTSE-III Optical Limits
  10. GRB 070808: Swift detection of a burst
  11. GRB061121A: PROMPT Observations
  12. GRB070805 XRT and UVOT afterglow candidate
  13. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  14. GRB070612A: Radio upper limit from GMRT
  15. GRB 070721B: correct afterglow position
  16. Swift/UVOT observations of GRB070805
  17. GRB 070805, Swift-BAT refined analysis
  18. GRB 070805: Swift XRT initial analysis.
  19. GRB 070805: Swift/UVOT initial analysis
  20. GRB 070805: Swift detection of a burst
  21. UVOT observations of SAXJ1810.8-2609
  22. Swift detection of a outburst from SAX J1810.8-2609
  23. VLA non-detection of GRB 070721B
  24. GRB 070802: REM optical observations
  25. GRB 070724B: Swift-XRT afterglow confirmation
  26. GRB 070802: Swift-XRT refined analysis
  27. GRB070802: Swift/UVOT upper limits
  28. GRB 070802: Confirmation of the optical afterglow
  29. GRB 070802, Swift-BAT refined analysis
  30. GRB 070802: VLT redshift
  31. GRB 070802: refined Swift XRT position
  32. GRB 070802: V-band detection of the candidate afterglow
  33. GRB 070802: LCO I-band candidate
  34. GRB 070802: GROND J band candidate
  35. GRB 070802: LCO optical observations
  36. GRB 070802: Swift detection of a burst
  37. GRB 070731, Swift-BAT refined analysis
  38. Konus-A observation of GRB 070729
  39. Swift/UVOT detection of GRB070714B
  40. AGILE-ACS position for the SGR 1806-20 July 27 burst
  41. GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
  42. GRB 070729: LCO optical imaging
  43. VLA upper limit on short hard burst GRB 070714B
  44. Intense burst from SGR 1806-20 detected on July 27
  45. GRB070729: Swift/UVOT upper limits
  46. GRB 070729: Swift-XRT refined analysis
  47. GRB 070729, Swift-BAT refined analysis
  48. GRB 070729: Magellan NIR Observations
  49. GRB 070724B: P60 Observations
  50. GRB 070729: Swift detection of a short hard burst
  51. GRB 070724B: Swift/UVOT Upper limits
  52. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  53. GRB 070724B: Swift-XRT afterglow likely candidate
  54. GRB 070721A: optical observations
  55. GRB 070724A: further VLT observations
  56. GRB 070724B: Suzaku WAM observation of the prompt emission
  57. Konus-Wind observation of GRB 070724B
  58. GRB 070724B: Analysis of AGILE gamma-ray data
  59. GRB 070724B: Swift-XRT afterglow candidates
  60. GRB 070724b: First Gamma Ray Burst Localization by SuperAGILE onboard
  61. Four radio sources in Swift-XRT error box of GRB 070724
  62. GRB 070724: optical observations
  63. GRB070724: Host galaxy redshift
  64. GRB 070724: P60 and Gemini Observations
  65. GRB 060814 - Keck host detection and redshift
  66. GRB 070724: IR observations
  67. GRB 070724: Closer association with DSS source
  68. Swift/UVOT refined analysis of GRB070724
  69. GRB 070724: Swift-XRT Team refined analysis
  70. GRB 070724: Pre-Imaging Shows a Source in the XRT Error Circle
  71. Short-Hard GRB070714B: PROMPT Observations
  72. GRB 070724, Swift-BAT refined analysis of a short burst
  73. GRB 070721B: further observations and analysis
  74. GRB 070724: Swift detection of a burst
  75. GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
  76. GRB 070714B: Keck observations
  77. GRB 070721B: optical observations and proposed redshift
  78. Swift/UVOT observations of GRB070721B optical afterglow.
  79. GRB 070721B, Further Swift-BAT refined analysis
  80. Swift/UVOT Observations of GRB070721A
  81. GRB 070721B : Faulkes Telescope South observations
  82. GRB 070721B: Swift-XRT refined analysis
  83. GRB 070721A : Faulkes Telescope South optical limit
  84. GRB 070721A: Swift/XRT refined analysis
  85. GRB 070721B, Swift-BAT refined analysis
  86. GRB 070721A, Swift-BAT refined analysis
  87. GRB070721B: A bright UVOT candidate
  88. GRB 070721B: Swift detection of a burst
  89. GRB 070721: Swift detection of a possible burst
  90. GRB 070714B: Swift/BAT and Suzaku/WAM joint spectral analysis
  91. GRB 070714B : Suzaku WAM observation of the prompt emission
  92. GRB 070714A: Swift-BAT T_zero
  93. GRB070714B: TNG NIR observations
  94. Erratum : Suzaku WAM observation of GRB 070704
  95. GRB 070714A: Swift/UVOT Upper limits
  96. GRB 070714B: Swift/UVOT Upper Limits
  97. GRB 070714B: Swift-BAT spectral lag for the SHB
  98. GRB 070714B: confirmation of optical afterglow
  99. GRB 070616: No Evidence for I Band Afterglow
  100. GRB 070714A: Swift XRT refined analysis

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