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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. GRB050117: Palomar WIRC Ks-band observations
  2. GRB050117b: Swift-BAT detection of a weak burst
  3. GRB050117: optical observation
  4. GRB 050117, I-band observations
  5. GRB 050117: Optical observation
  6. GRB050117: Refined XRT position
  7. GRB050117: MASTER optical observations
  8. MASTER:GRB050117 SWIFT
  9. GRB050117: Swift-BAT detection of a long multi-peaked burst
  10. GRB050117: Swift XRT Position
  11. SGR 1806-20: RXTE/PCA pulse frequency during flare
  12. Triangulation of Short Hard GRB050112 (large error box)
  13. SGR 1806-20: Further VLA Observations
  14. SGR 1806-20: Further low frequency GMRT results
  15. SGR 1806-20: Further VLA Observations
  16. SGR1806-20: Swift-BAT observations of two additional bursts
  17. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  18. Further VLA observations of SGR 1806-20
  19. SGR 1806-20 and extragalactic short-duration GRBs
  20. Further ATCA observations of SGR 1806-20
  21. Fourth Epoch VLA observations of SGR 1806-20
  22. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  23. SGR 1806-20: Temporal and Spectral behavior of radio transient
  24. ATCA observations of SGR 1806-20
  25. SGR 1806-20, RHESSI observations of the 041227 giant flare
  26. Third epoch observations of SGR 1806-20 with VLA
  27. Second Epoch VLA observations of SGR 1806-20
  28. Second-epoch VLA observations of SGR 1806-20
  29. SGR1806: Detection of a Sudden Ionospheric Disturbance
  30. DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
  31. VLA observations of SGR 1806-20
  32. SGR1806 VLA Observations
  33. VLA observations of SGR 1806-20
  34. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  35. GRB 041217: Optical observations
  36. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  37. GRB041219, early time observations
  38. Detection of the SGR 1806-20 giant outburst back-scattered by the
  39. The giant outburst from SGR 1806-20
  40. IPN localization of giant flare from SGR1806-20
  41. Giant flare from SGR 1806-20 detected by INTEGRAL
  42. GRB041228: ROTSE-III Optical Observations
  43. GRB041228: Swift-BAT detection of a burst
  44. GRB041219; RXTE ASM Observations
  45. NIR Observations of GRB 041219
  46. GRB041226: ROTSE-III Optical Observations
  47. GRB041226: Swift-BAT detection of a burst
  48. GRB041223: decay of the afterglow
  49. GRB041224: ROTSE-III Optical Observations
  50. GRB 041224: near-infrared observations with REM
  51. GRB 041223: XRT afterglow spectrum and light curve
  52. GRB 041223 Fluence measured by Swift-BAT
  53. GRB041224: Swift-BAT detection of a soft burst
  54. GRB041223: optical and NIR observations with REM
  55. Swift-BAT Time History of GRB041219
  56. GRB 041219: TAROT optical observations
  57. GRB 041218: TAROT optical observations
  58. GRB 041223: J-band observations of the afterglow
  59. GRB 041223: Detection of Optical Transient with LCO40
  60. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  61. GRB 041219c: PROMPT Observations
  62. GRB041223: ROTSE-III Optical Observations
  63. GRB041223: Swift-BAT detection of a bright long burst
  64. GRB 041218: optical observations
  65. Very high activity of SGR 1806-20
  66. GRB 041219: Second Epoch WSRT Radio Observations
  67. GRB 041219: WSRT Radio Afterglow Detection
  68. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  69. GRB 041218: Optical observations
  70. GRB 041219 : optical follow-up observations
  71. GRB041220: Swift-BAT burst
  72. Deep RAPTOR observations during GRB 041219
  73. GRB 041218 Optical Observations
  74. GRB 041219 Optical Observations
  75. GRB041219c: Third Burst in One Day from Swift-BAT
  76. GRB041219: Optical Afterglow Detection
  77. GRB041219: Continued NIR Observations
  78. GRB041219b: A Swift-BAT burst
  79. GRB 041219 ,optical observation
  80. GRB 041219: Radio Afterglow Detection
  81. GRB 041218 : Radio Observations
  82. GRB 041218: R-band optical observations
  83. GRB041218: Liverpool Telescope optical observations
  84. GRB041218: optical observations
  85. GRB041219: Confirmed NIR Afterglow
  86. GRB041218: Continued P60 Optical Observations
  87. Swift-BAT detection of the bright long burst GRB041219
  88. GRB 041218: Optical Observation
  89. GRB 041219: Infrared Afterglow Candidate
  90. GRB041219, BVRcIc field calibration
  91. GRB 041219: Infrared Afterglow Candidate
  92. GRB041218, BVRcIc field calibration
  93. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  94. GRB041219: P60 Optical Observations
  95. GRB 041219 - A long GRB detected by INTEGRAL
  96. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  97. GRB 041217: PROMPT Observations
  98. GRB041218: optical observations
  99. GRB041217: optical limit 30 min after GRB
  100. GRB 041218; optical candidate

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