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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"

20967 results found.

  1. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  2. GRB050215b: Swift UVOT Detection of Afterglow Emission
  3. GRB 050215B: Radio Observations
  4. GRB 050215b: XRT confirmation of IR afterglow candidate
  5. GRB050215b: P60 Optical Observations
  6. GRB 050215b: Swift XRT Source Variability
  7. GRB 050215b : Lulin follow-up observation
  8. GRB 050215b, BOOTES-2 simultaneous optical observations
  9. GRB 050215b: Swift XRT Observations
  10. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  11. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  12. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  13. GRB050215B: ROTSE-III optical observations
  14. GRB050215A: ROTSE-III Optical Observations
  15. GRB050209: TAROT optical observations
  16. short/hard GRB 050202, optical observations
  17. GRB050209: REM optical observations
  18. GRB 050209 Optical observations
  19. GRB050209: P60 Optical Observations
  20. GRB 050128: Radio observations
  21. Further analysis of the short Swift-BAT GRB 050202
  22. GRB 050202: Second epoch radio observations
  23. GRB 050129: Optical observations
  24. GRB050202: Radio Observations
  25. GRB 050202: Optical observations with LCO40
  26. GRB 050128 Optical observation with REM
  27. GRB050128: Faulkes Telescope South observations
  28. GRB 050124: Radio Observations
  29. GRB 050128: near-infrared observations with REM
  30. GRB050128,optical observations
  31. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  32. GRB 050126: Radio Observations
  33. GRB050128 Swift-BAT observations
  34. GRB 050128: Swift XRT prompt afterglow position
  35. HETE #3667: P60 Observations
  36. GRB 050124: K-band afterglow observations
  37. GRB050126: MASTER optical observations
  38. GRB 050126: Prompt XRT detection and localization
  39. GRB050124: No Swift UVOT Detection of Afterglow Emission
  40. GRB 050124, SMARTS optical/IR observations
  41. GRB 050117a: Radio Observations
  42. GRB 050124: NIR Candidates from Keck/NIRC
  43. GRB 050124 : Lulin R-band follow-up observation
  44. GRB050124: Updated Swift XRT Position and Fluxes
  45. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  46. GRB 050123 : I-band follow-up observation
  47. GRB 050123: KAIT observations
  48. GRB050123: P60 Observations
  49. CFHTLS optical transient unlikely to be a GRB
  50. GRB050117a: Radio Observations
  51. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  52. GRB050117: Palomar WIRC Ks-band observations
  53. GRB 050117, I-band observations
  54. GRB050117: Refined XRT position
  55. GRB050117: MASTER optical observations
  56. MASTER:GRB050117 SWIFT
  57. SGR 1806-20: Further VLA Observations
  58. SGR 1806-20: Further low frequency GMRT results
  59. SGR 1806-20: Further VLA Observations
  60. SGR1806-20: Swift-BAT observations of two additional bursts
  61. Further VLA observations of SGR 1806-20
  62. Further ATCA observations of SGR 1806-20
  63. Fourth Epoch VLA observations of SGR 1806-20
  64. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  65. ATCA observations of SGR 1806-20
  66. SGR 1806-20, RHESSI observations of the 041227 giant flare
  67. Third epoch observations of SGR 1806-20 with VLA
  68. Second Epoch VLA observations of SGR 1806-20
  69. Second-epoch VLA observations of SGR 1806-20
  70. SGR1806: Detection of a Sudden Ionospheric Disturbance
  71. VLA observations of SGR 1806-20
  72. SGR1806 VLA Observations
  73. VLA observations of SGR 1806-20
  74. GRB 041217: Optical observations
  75. GRB041219, early time observations
  76. The giant outburst from SGR 1806-20
  77. GRB041228: ROTSE-III Optical Observations
  78. GRB041219; RXTE ASM Observations
  79. NIR Observations of GRB 041219
  80. GRB041226: ROTSE-III Optical Observations
  81. GRB041223: decay of the afterglow
  82. GRB041224: ROTSE-III Optical Observations
  83. GRB 041224: near-infrared observations with REM
  84. GRB041223: optical and NIR observations with REM
  85. Swift-BAT Time History of GRB041219
  86. GRB 041219: TAROT optical observations
  87. GRB 041218: TAROT optical observations
  88. GRB 041223: J-band observations of the afterglow
  89. GRB 041223: Detection of Optical Transient with LCO40
  90. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  91. GRB 041219c: PROMPT Observations
  92. GRB041223: ROTSE-III Optical Observations
  93. GRB 041218: optical observations
  94. GRB 041219: Second Epoch WSRT Radio Observations
  95. GRB 041219: WSRT Radio Afterglow Detection
  96. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  97. GRB 041218: Optical observations
  98. GRB 041219 : optical follow-up observations
  99. Deep RAPTOR observations during GRB 041219
  100. GRB 041218 Optical Observations

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