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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. GRB 050129: a weak long GRB detected with INTEGRAL
  2. SGR1806-20: Swift-BAT detection of a large normal burst
  3. GRB050128: Faulkes Telescope South observations
  4. GRB 050124: Radio Observations
  5. GRB 050128: near-infrared observations with REM
  6. GRB050128,optical observations
  7. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  8. GRB050126: Updated Swift XRT Position
  9. SGR 1806-20: GMRT results at 240 MHz band.
  10. SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
  11. GRB 050126: Radio Observations
  12. GRB050128 Swift-BAT observations
  13. GRB 050128: Swift XRT prompt afterglow position
  14. HETE #3667: P60 Observations
  15. GRB 050124: K-band afterglow observations
  16. GRB050126: MASTER optical limit for KECK OT
  17. GRB050126: Burst Parameters Measured by BAT
  18. GRB050126: MASTER optical observations
  19. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  20. GRB 050126: Prompt XRT detection and localization
  21. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  22. GRB050124: No Swift UVOT Detection of Afterglow Emission
  23. GRB 050124, SMARTS optical/IR observations
  24. GRB 050117a: Radio Observations
  25. GRB 050124 I-band observation
  26. GRB 050124: NIR Candidates from Keck/NIRC
  27. GRB050124,optical observation
  28. GRB 050124 : Lulin R-band follow-up observation
  29. GRB050124: Updated Swift XRT Position and Fluxes
  30. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  31. GRB050124: Refined BAT position, spectral and fluence information
  32. GRB050124: Swift-BAT position of a double-peaked burst
  33. GRB 050123 : I-band follow-up observation
  34. GRB050123: optical limit 1.8h before GRB
  35. GRB050123,optical observation
  36. GRB 050123: KAIT observations
  37. GRB050123: P60 Observations
  38. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  39. CFHTLS optical transient unlikely to be a GRB
  40. Unusual optical transient (GRB ???)
  41. GRB050117a: Radio Observations
  42. GRB050117a: Refined analysis
  43. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  44. GRB050117: Palomar WIRC Ks-band observations
  45. GRB050117b: Swift-BAT detection of a weak burst
  46. GRB050117: optical observation
  47. GRB 050117, I-band observations
  48. GRB 050117: Optical observation
  49. GRB050117: Refined XRT position
  50. GRB050117: MASTER optical observations
  51. MASTER:GRB050117 SWIFT
  52. GRB050117: Swift-BAT detection of a long multi-peaked burst
  53. GRB050117: Swift XRT Position
  54. SGR 1806-20: RXTE/PCA pulse frequency during flare
  55. Triangulation of Short Hard GRB050112 (large error box)
  56. SGR 1806-20: Further VLA Observations
  57. SGR 1806-20: Further low frequency GMRT results
  58. SGR 1806-20: Further VLA Observations
  59. SGR1806-20: Swift-BAT observations of two additional bursts
  60. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  61. Further VLA observations of SGR 1806-20
  62. SGR 1806-20 and extragalactic short-duration GRBs
  63. Further ATCA observations of SGR 1806-20
  64. Fourth Epoch VLA observations of SGR 1806-20
  65. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  66. SGR 1806-20: Temporal and Spectral behavior of radio transient
  67. ATCA observations of SGR 1806-20
  68. SGR 1806-20, RHESSI observations of the 041227 giant flare
  69. Third epoch observations of SGR 1806-20 with VLA
  70. Second Epoch VLA observations of SGR 1806-20
  71. Second-epoch VLA observations of SGR 1806-20
  72. SGR1806: Detection of a Sudden Ionospheric Disturbance
  73. DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
  74. VLA observations of SGR 1806-20
  75. SGR1806 VLA Observations
  76. VLA observations of SGR 1806-20
  77. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  78. GRB 041217: Optical observations
  79. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  80. GRB041219, early time observations
  81. Detection of the SGR 1806-20 giant outburst back-scattered by the
  82. The giant outburst from SGR 1806-20
  83. IPN localization of giant flare from SGR1806-20
  84. Giant flare from SGR 1806-20 detected by INTEGRAL
  85. GRB041228: ROTSE-III Optical Observations
  86. GRB041228: Swift-BAT detection of a burst
  87. GRB041219; RXTE ASM Observations
  88. NIR Observations of GRB 041219
  89. GRB041226: ROTSE-III Optical Observations
  90. GRB041226: Swift-BAT detection of a burst
  91. GRB041223: decay of the afterglow
  92. GRB041224: ROTSE-III Optical Observations
  93. GRB 041224: near-infrared observations with REM
  94. GRB 041223: XRT afterglow spectrum and light curve
  95. GRB 041223 Fluence measured by Swift-BAT
  96. GRB041224: Swift-BAT detection of a soft burst
  97. GRB041223: optical and NIR observations with REM
  98. Swift-BAT Time History of GRB041219
  99. GRB 041219: TAROT optical observations
  100. GRB 041218: TAROT optical observations

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