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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"

20957 results found.

  1. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  2. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  3. GRB050215B: ROTSE-III optical observations
  4. GRB050215A: ROTSE-III Optical Observations
  5. GRB050209: TAROT optical observations
  6. short/hard GRB 050202, optical observations
  7. GRB050209: REM optical observations
  8. GRB 050209 Optical observations
  9. GRB050209: P60 Optical Observations
  10. GRB 050128: Radio observations
  11. Further analysis of the short Swift-BAT GRB 050202
  12. GRB 050202: Second epoch radio observations
  13. GRB 050129: Optical observations
  14. GRB050202: Radio Observations
  15. GRB 050202: Optical observations with LCO40
  16. GRB 050128 Optical observation with REM
  17. GRB050128: Faulkes Telescope South observations
  18. GRB 050124: Radio Observations
  19. GRB 050128: near-infrared observations with REM
  20. GRB050128,optical observations
  21. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  22. GRB 050126: Radio Observations
  23. GRB050128 Swift-BAT observations
  24. GRB 050128: Swift XRT prompt afterglow position
  25. HETE #3667: P60 Observations
  26. GRB 050124: K-band afterglow observations
  27. GRB050126: MASTER optical observations
  28. GRB 050126: Prompt XRT detection and localization
  29. GRB050124: No Swift UVOT Detection of Afterglow Emission
  30. GRB 050124, SMARTS optical/IR observations
  31. GRB 050117a: Radio Observations
  32. GRB 050124: NIR Candidates from Keck/NIRC
  33. GRB 050124 : Lulin R-band follow-up observation
  34. GRB050124: Updated Swift XRT Position and Fluxes
  35. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  36. GRB 050123 : I-band follow-up observation
  37. GRB 050123: KAIT observations
  38. GRB050123: P60 Observations
  39. CFHTLS optical transient unlikely to be a GRB
  40. GRB050117a: Radio Observations
  41. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  42. GRB050117: Palomar WIRC Ks-band observations
  43. GRB 050117, I-band observations
  44. GRB050117: Refined XRT position
  45. GRB050117: MASTER optical observations
  46. MASTER:GRB050117 SWIFT
  47. SGR 1806-20: Further VLA Observations
  48. SGR 1806-20: Further low frequency GMRT results
  49. SGR 1806-20: Further VLA Observations
  50. SGR1806-20: Swift-BAT observations of two additional bursts
  51. Further VLA observations of SGR 1806-20
  52. Further ATCA observations of SGR 1806-20
  53. Fourth Epoch VLA observations of SGR 1806-20
  54. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  55. ATCA observations of SGR 1806-20
  56. SGR 1806-20, RHESSI observations of the 041227 giant flare
  57. Third epoch observations of SGR 1806-20 with VLA
  58. Second Epoch VLA observations of SGR 1806-20
  59. Second-epoch VLA observations of SGR 1806-20
  60. SGR1806: Detection of a Sudden Ionospheric Disturbance
  61. VLA observations of SGR 1806-20
  62. SGR1806 VLA Observations
  63. VLA observations of SGR 1806-20
  64. GRB 041217: Optical observations
  65. GRB041219, early time observations
  66. The giant outburst from SGR 1806-20
  67. GRB041228: ROTSE-III Optical Observations
  68. GRB041219; RXTE ASM Observations
  69. NIR Observations of GRB 041219
  70. GRB041226: ROTSE-III Optical Observations
  71. GRB041223: decay of the afterglow
  72. GRB041224: ROTSE-III Optical Observations
  73. GRB 041224: near-infrared observations with REM
  74. GRB041223: optical and NIR observations with REM
  75. Swift-BAT Time History of GRB041219
  76. GRB 041219: TAROT optical observations
  77. GRB 041218: TAROT optical observations
  78. GRB 041223: J-band observations of the afterglow
  79. GRB 041223: Detection of Optical Transient with LCO40
  80. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  81. GRB 041219c: PROMPT Observations
  82. GRB041223: ROTSE-III Optical Observations
  83. GRB 041218: optical observations
  84. GRB 041219: Second Epoch WSRT Radio Observations
  85. GRB 041219: WSRT Radio Afterglow Detection
  86. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  87. GRB 041218: Optical observations
  88. GRB 041219 : optical follow-up observations
  89. Deep RAPTOR observations during GRB 041219
  90. GRB 041218 Optical Observations
  91. GRB 041219 Optical Observations
  92. GRB041219: Optical Afterglow Detection
  93. GRB041219: Continued NIR Observations
  94. GRB 041219: Radio Afterglow Detection
  95. GRB 041218 : Radio Observations
  96. GRB 041218: R-band optical observations
  97. GRB041218: Liverpool Telescope optical observations
  98. GRB041218: optical observations
  99. GRB041218: Continued P60 Optical Observations
  100. GRB 041219: Infrared Afterglow Candidate

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