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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. Four radio sources in Swift-XRT error box of GRB 070724
  2. GRB 070724: optical observations
  3. GRB070724: Host galaxy redshift
  4. GRB 070724: P60 and Gemini Observations
  5. GRB 060814 - Keck host detection and redshift
  6. GRB 070724: IR observations
  7. GRB 070724: Closer association with DSS source
  8. Swift/UVOT refined analysis of GRB070724
  9. GRB 070724: Swift-XRT Team refined analysis
  10. GRB 070724: Pre-Imaging Shows a Source in the XRT Error Circle
  11. Short-Hard GRB070714B: PROMPT Observations
  12. GRB 070724, Swift-BAT refined analysis of a short burst
  13. GRB 070721B: further observations and analysis
  14. GRB 070724: Swift detection of a burst
  15. GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
  16. GRB 070714B: Keck observations
  17. GRB 070721B: optical observations and proposed redshift
  18. Swift/UVOT observations of GRB070721B optical afterglow.
  19. GRB 070721B, Further Swift-BAT refined analysis
  20. Swift/UVOT Observations of GRB070721A
  21. GRB 070721B : Faulkes Telescope South observations
  22. GRB 070721B: Swift-XRT refined analysis
  23. GRB 070721A : Faulkes Telescope South optical limit
  24. GRB 070721A: Swift/XRT refined analysis
  25. GRB 070721B, Swift-BAT refined analysis
  26. GRB 070721A, Swift-BAT refined analysis
  27. GRB070721B: A bright UVOT candidate
  28. GRB 070721B: Swift detection of a burst
  29. GRB 070721: Swift detection of a possible burst
  30. GRB 070714B: Swift/BAT and Suzaku/WAM joint spectral analysis
  31. GRB 070714B : Suzaku WAM observation of the prompt emission
  32. GRB 070714A: Swift-BAT T_zero
  33. GRB070714B: TNG NIR observations
  34. Erratum : Suzaku WAM observation of GRB 070704
  35. GRB 070714A: Swift/UVOT Upper limits
  36. GRB 070714B: Swift/UVOT Upper Limits
  37. GRB 070714B: Swift-BAT spectral lag for the SHB
  38. GRB 070714B: confirmation of optical afterglow
  39. GRB 070616: No Evidence for I Band Afterglow
  40. GRB 070714A: Swift XRT refined analysis
  41. GRB070714B: Swift-XRT refined analysis
  42. GRB 070707: Swift-XRT follow-up observations
  43. GRB 070714b ("Bastille"): Optical Pre-Imaging (Clarification)
  44. GRB 070714 ("Bastille"): Optical Pre-Imaging
  45. GRB 070714B, Swift-BAT refined analysis of the short hard burst
  46. GRB 070714A, Swift-BAT refined analysis
  47. GRB 070714 : Liverpool Telescope optical counterpart ?
  48. GRB 070714: Swift detection of a bright burst, possibly short
  49. Swift detection of a possible burst (Trigger 284850)
  50. SN 2007bg - off-axis GRB?
  51. GRB 070704: RTT150 optical observations
  52. GRB 070704: Suzaku/WAM observation of the prompt emission
  53. Konus-Wind observation of GRB 070707
  54. Updated Swift/UVOT calibration
  55. GRB 070707: optical afterglow
  56. GRB 070707: object inside XRT error circle
  57. Swift/UVOT Observations of GRB070707
  58. Swift XRT observation of GRB 070707
  59. GRB 070707: VLT observations
  60. INTEGRAL GRB 070707 is a short hard burst
  61. INTEGRAL GRB 070707 is a short hard burst
  62. GRB 070707: A long GRB detected by INTEGRAL
  63. GRB 070707: A long GRB detected by INTEGRAL
  64. GRB 070429B: NIR Observations
  65. GRB070704: FAVOR optical observations
  66. GRB 070704 : Liverpool Telescope Observations
  67. GRB 070611: VLT observations
  68. VLA detection of GRB 070612A in C Band
  69. Konus-Wind observation of GRB 070626
  70. GRB 070704: Swift-XRT refined analysis
  71. Swift/UVOT Observations of GRB070704
  72. GRB 070704, Swift-BAT refined analysis
  73. GRB 070704: Correction to GCN Circ 6594
  74. GRB 070704: Swift detection of a burst
  75. GRB 070626: Suzaku/WAM observation of the prompt emission
  76. GRB 070626: IPN localization and Konus spectrum of a bright long burst
  77. GRB 070628 Swift-UVOT Refined Analysis
  78. GRB 070628: NIR detection of afterglow
  79. GRB 070628, Swift-BAT refined analysis
  80. GRB 070628: TAROT La Silla observatory optical observations
  81. GRB 070628: Swift XRT refined analysis
  82. GRB 070628: Watcher Observations
  83. Swift UVOT Observations of GRB 070628
  84. GRB 070628: Swift detection of a possible burst
  85. GRB 070612A: Allen Telescope Array Observations
  86. IBAS Alert n. 4638: Not a GRB
  87. OT20050728 was not an optical GRB afterglow
  88. INTEGRAL burst GRB070615: X-ray continued observations
  89. GRB 070616 : WIDGET simultaneous optical observations
  90. GRB 070616: Suzaku/WAM observation of the prompt emission
  91. IBAS Alert n.4637: not a GRB
  92. GRB 070612A: Second Epoch WSRT Radio Observations
  93. GRB070621: RTT150 optical observations
  94. GRB 070621: VLT optical observations
  95. GRB 070621: Swift/UVOT Upper Limits
  96. Keck Laser Guide Star Adaptive Optics Imaging of GRB 070621
  97. GRB 070621: Swift-BAT refined analysis
  98. WHT observations of GRB070621
  99. GRB070621: Swift XRT refined analysis
  100. GRB 070621: Gemini South optical imaging

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