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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. Intense burst from SGR 1806-20 detected on July 27
  2. GRB070729: Swift/UVOT upper limits
  3. GRB 070729: Swift-XRT refined analysis
  4. GRB 070729, Swift-BAT refined analysis
  5. GRB 070729: Magellan NIR Observations
  6. GRB 070724B: P60 Observations
  7. GRB 070729: Swift detection of a short hard burst
  8. GRB 070724B: Swift/UVOT Upper limits
  9. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  10. GRB 070724B: Swift-XRT afterglow likely candidate
  11. GRB 070721A: optical observations
  12. GRB 070724A: further VLT observations
  13. GRB 070724B: Suzaku WAM observation of the prompt emission
  14. Konus-Wind observation of GRB 070724B
  15. GRB 070724B: Analysis of AGILE gamma-ray data
  16. GRB 070724B: Swift-XRT afterglow candidates
  17. GRB 070724b: First Gamma Ray Burst Localization by SuperAGILE onboard
  18. Four radio sources in Swift-XRT error box of GRB 070724
  19. GRB 070724: optical observations
  20. GRB070724: Host galaxy redshift
  21. GRB 070724: P60 and Gemini Observations
  22. GRB 060814 - Keck host detection and redshift
  23. GRB 070724: IR observations
  24. GRB 070724: Closer association with DSS source
  25. Swift/UVOT refined analysis of GRB070724
  26. GRB 070724: Swift-XRT Team refined analysis
  27. GRB 070724: Pre-Imaging Shows a Source in the XRT Error Circle
  28. Short-Hard GRB070714B: PROMPT Observations
  29. GRB 070724, Swift-BAT refined analysis of a short burst
  30. GRB 070721B: further observations and analysis
  31. GRB 070724: Swift detection of a burst
  32. GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
  33. GRB 070714B: Keck observations
  34. GRB 070721B: optical observations and proposed redshift
  35. Swift/UVOT observations of GRB070721B optical afterglow.
  36. GRB 070721B, Further Swift-BAT refined analysis
  37. Swift/UVOT Observations of GRB070721A
  38. GRB 070721B : Faulkes Telescope South observations
  39. GRB 070721B: Swift-XRT refined analysis
  40. GRB 070721A : Faulkes Telescope South optical limit
  41. GRB 070721A: Swift/XRT refined analysis
  42. GRB 070721B, Swift-BAT refined analysis
  43. GRB 070721A, Swift-BAT refined analysis
  44. GRB070721B: A bright UVOT candidate
  45. GRB 070721B: Swift detection of a burst
  46. GRB 070721: Swift detection of a possible burst
  47. GRB 070714B: Swift/BAT and Suzaku/WAM joint spectral analysis
  48. GRB 070714B : Suzaku WAM observation of the prompt emission
  49. GRB 070714A: Swift-BAT T_zero
  50. GRB070714B: TNG NIR observations
  51. Erratum : Suzaku WAM observation of GRB 070704
  52. GRB 070714A: Swift/UVOT Upper limits
  53. GRB 070714B: Swift/UVOT Upper Limits
  54. GRB 070714B: Swift-BAT spectral lag for the SHB
  55. GRB 070714B: confirmation of optical afterglow
  56. GRB 070616: No Evidence for I Band Afterglow
  57. GRB 070714A: Swift XRT refined analysis
  58. GRB070714B: Swift-XRT refined analysis
  59. GRB 070707: Swift-XRT follow-up observations
  60. GRB 070714b ("Bastille"): Optical Pre-Imaging (Clarification)
  61. GRB 070714 ("Bastille"): Optical Pre-Imaging
  62. GRB 070714B, Swift-BAT refined analysis of the short hard burst
  63. GRB 070714A, Swift-BAT refined analysis
  64. GRB 070714 : Liverpool Telescope optical counterpart ?
  65. GRB 070714: Swift detection of a bright burst, possibly short
  66. Swift detection of a possible burst (Trigger 284850)
  67. SN 2007bg - off-axis GRB?
  68. GRB 070704: RTT150 optical observations
  69. GRB 070704: Suzaku/WAM observation of the prompt emission
  70. Konus-Wind observation of GRB 070707
  71. Updated Swift/UVOT calibration
  72. GRB 070707: optical afterglow
  73. GRB 070707: object inside XRT error circle
  74. Swift/UVOT Observations of GRB070707
  75. Swift XRT observation of GRB 070707
  76. GRB 070707: VLT observations
  77. INTEGRAL GRB 070707 is a short hard burst
  78. INTEGRAL GRB 070707 is a short hard burst
  79. GRB 070707: A long GRB detected by INTEGRAL
  80. GRB 070707: A long GRB detected by INTEGRAL
  81. GRB 070429B: NIR Observations
  82. GRB070704: FAVOR optical observations
  83. GRB 070704 : Liverpool Telescope Observations
  84. GRB 070611: VLT observations
  85. VLA detection of GRB 070612A in C Band
  86. Konus-Wind observation of GRB 070626
  87. GRB 070704: Swift-XRT refined analysis
  88. Swift/UVOT Observations of GRB070704
  89. GRB 070704, Swift-BAT refined analysis
  90. GRB 070704: Correction to GCN Circ 6594
  91. GRB 070704: Swift detection of a burst
  92. GRB 070626: Suzaku/WAM observation of the prompt emission
  93. GRB 070626: IPN localization and Konus spectrum of a bright long burst
  94. GRB 070628 Swift-UVOT Refined Analysis
  95. GRB 070628: NIR detection of afterglow
  96. GRB 070628, Swift-BAT refined analysis
  97. GRB 070628: TAROT La Silla observatory optical observations
  98. GRB 070628: Swift XRT refined analysis
  99. GRB 070628: Watcher Observations
  100. Swift UVOT Observations of GRB 070628

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