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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').
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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"

45430 results found.

  1. GRB 050124 : Lulin R-band follow-up observation
  2. GRB050124: Updated Swift XRT Position and Fluxes
  3. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  4. GRB050124: Refined BAT position, spectral and fluence information
  5. GRB050124: Swift-BAT position of a double-peaked burst
  6. GRB 050123 : I-band follow-up observation
  7. GRB050123: optical limit 1.8h before GRB
  8. GRB050123,optical observation
  9. GRB 050123: KAIT observations
  10. GRB050123: P60 Observations
  11. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  12. CFHTLS optical transient unlikely to be a GRB
  13. Unusual optical transient (GRB ???)
  14. GRB050117a: Radio Observations
  15. GRB050117a: Refined analysis
  16. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  17. GRB050117: Palomar WIRC Ks-band observations
  18. GRB050117b: Swift-BAT detection of a weak burst
  19. GRB050117: optical observation
  20. GRB 050117, I-band observations
  21. GRB 050117: Optical observation
  22. GRB050117: Refined XRT position
  23. GRB050117: MASTER optical observations
  24. MASTER:GRB050117 SWIFT
  25. GRB050117: Swift-BAT detection of a long multi-peaked burst
  26. GRB050117: Swift XRT Position
  27. SGR 1806-20: RXTE/PCA pulse frequency during flare
  28. Triangulation of Short Hard GRB050112 (large error box)
  29. SGR 1806-20: Further low frequency GMRT results
  30. SGR1806-20: Swift-BAT observations of two additional bursts
  31. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  32. Further VLA observations of SGR 1806-20
  33. SGR 1806-20 and extragalactic short-duration GRBs
  34. Further ATCA observations of SGR 1806-20
  35. Fourth Epoch VLA observations of SGR 1806-20
  36. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  37. SGR 1806-20: Temporal and Spectral behavior of radio transient
  38. ATCA observations of SGR 1806-20
  39. SGR 1806-20, RHESSI observations of the 041227 giant flare
  40. Third epoch observations of SGR 1806-20 with VLA
  41. Second Epoch VLA observations of SGR 1806-20
  42. Second-epoch VLA observations of SGR 1806-20
  43. SGR1806: Detection of a Sudden Ionospheric Disturbance
  44. DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
  45. VLA observations of SGR 1806-20
  46. SGR1806 VLA Observations
  47. VLA observations of SGR 1806-20
  48. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  49. GRB 041217: Optical observations
  50. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  51. GRB041219, early time observations
  52. Detection of the SGR 1806-20 giant outburst back-scattered by the
  53. The giant outburst from SGR 1806-20
  54. IPN localization of giant flare from SGR1806-20
  55. Giant flare from SGR 1806-20 detected by INTEGRAL
  56. GRB041228: ROTSE-III Optical Observations
  57. GRB041228: Swift-BAT detection of a burst
  58. GRB041219; RXTE ASM Observations
  59. NIR Observations of GRB 041219
  60. GRB041226: ROTSE-III Optical Observations
  61. GRB041226: Swift-BAT detection of a burst
  62. GRB041223: decay of the afterglow
  63. GRB041224: ROTSE-III Optical Observations
  64. GRB 041224: near-infrared observations with REM
  65. GRB 041223: XRT afterglow spectrum and light curve
  66. GRB 041223 Fluence measured by Swift-BAT
  67. GRB041224: Swift-BAT detection of a soft burst
  68. GRB041223: optical and NIR observations with REM
  69. Swift-BAT Time History of GRB041219
  70. GRB 041219: TAROT optical observations
  71. GRB 041218: TAROT optical observations
  72. GRB 041223: J-band observations of the afterglow
  73. GRB 041223: Detection of Optical Transient with LCO40
  74. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  75. GRB 041219c: PROMPT Observations
  76. GRB041223: ROTSE-III Optical Observations
  77. GRB041223: Swift-BAT detection of a bright long burst
  78. GRB 041218: optical observations
  79. Very high activity of SGR 1806-20
  80. GRB 041219: Second Epoch WSRT Radio Observations
  81. GRB 041219: WSRT Radio Afterglow Detection
  82. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  83. GRB 041218: Optical observations
  84. GRB 041219 : optical follow-up observations
  85. GRB041220: Swift-BAT burst
  86. Deep RAPTOR observations during GRB 041219
  87. GRB 041218 Optical Observations
  88. GRB 041219 Optical Observations
  89. GRB041219c: Third Burst in One Day from Swift-BAT
  90. GRB041219: Optical Afterglow Detection
  91. GRB041219: Continued NIR Observations
  92. GRB041219b: A Swift-BAT burst
  93. GRB 041219 ,optical observation
  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. GRB041219: Confirmed NIR Afterglow
  100. GRB041218: Continued P60 Optical Observations

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