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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"

27393 results found.

  1. GRB 050215b, BOOTES-2 simultaneous optical observations
  2. GRB050215A: ROTSE-III Optical Observations
  3. GRB050209: TAROT optical observations
  4. GRB 050209(=U11568): Duration and spectrum
  5. GRB050209: REM optical observations
  6. GRB 050209 I-band observation
  7. GRB 050209 Optical observations
  8. GRB050209: P60 Optical Observations
  9. GRB 050128: Radio observations
  10. Further analysis of the short Swift-BAT GRB 050202
  11. GRB 050202: Short burst detected by Swift-BAT
  12. GRB 050128 Optical observation with REM
  13. SGR1806-20: Swift-BAT detection of a large normal burst
  14. GRB 050128: near-infrared observations with REM
  15. GRB050128,optical observations
  16. GRB050128 Swift-BAT observations
  17. GRB 050128: Swift XRT prompt afterglow position
  18. GRB050126: MASTER optical limit for KECK OT
  19. GRB050126: Burst Parameters Measured by BAT
  20. GRB050126: MASTER optical observations
  21. GRB 050124 I-band observation
  22. GRB050124,optical observation
  23. GRB 050124 : Lulin R-band follow-up observation
  24. GRB050124: Updated Swift XRT Position and Fluxes
  25. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  26. GRB050124: Refined BAT position, spectral and fluence information
  27. GRB 050123 : I-band follow-up observation
  28. GRB050123,optical observation
  29. GRB 050123: KAIT observations
  30. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  31. GRB050117: Refined XRT position
  32. GRB050117: MASTER optical observations
  33. MASTER:GRB050117 SWIFT
  34. GRB050117: Swift XRT Position
  35. Triangulation of Short Hard GRB050112 (large error box)
  36. SGR 1806-20: Further VLA Observations
  37. SGR1806-20: Swift-BAT observations of two additional bursts
  38. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  39. Further VLA observations of SGR 1806-20
  40. SGR 1806-20 and extragalactic short-duration GRBs
  41. Further ATCA observations of SGR 1806-20
  42. Fourth Epoch VLA observations of SGR 1806-20
  43. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  44. ATCA observations of SGR 1806-20
  45. SGR 1806-20, RHESSI observations of the 041227 giant flare
  46. Third epoch observations of SGR 1806-20 with VLA
  47. Second Epoch VLA observations of SGR 1806-20
  48. Second-epoch VLA observations of SGR 1806-20
  49. SGR1806 VLA Observations
  50. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  51. GRB 041217: Optical observations
  52. GRB041228: Swift-BAT detection of a burst
  53. GRB041219; RXTE ASM Observations
  54. NIR Observations of GRB 041219
  55. GRB041226: Swift-BAT detection of a burst
  56. GRB041223: decay of the afterglow
  57. GRB 041224: near-infrared observations with REM
  58. GRB 041223 Fluence measured by Swift-BAT
  59. GRB041223: optical and NIR observations with REM
  60. Swift-BAT Time History of GRB041219
  61. GRB 041219: TAROT optical observations
  62. GRB 041218: TAROT optical observations
  63. GRB 041223: J-band observations of the afterglow
  64. GRB 041219c: PROMPT Observations
  65. GRB041223: Swift-BAT detection of a bright long burst
  66. GRB 041218: optical observations
  67. GRB 041219 : optical follow-up observations
  68. Deep RAPTOR observations during GRB 041219
  69. GRB 041218 Optical Observations
  70. GRB041219: Continued NIR Observations
  71. GRB 041219 ,optical observation
  72. GRB 041219: Radio Afterglow Detection
  73. GRB 041218 : Radio Observations
  74. GRB 041218: R-band optical observations
  75. GRB041218: optical observations
  76. GRB041219: Confirmed NIR Afterglow
  77. Swift-BAT detection of the bright long burst GRB041219
  78. GRB 041219: Infrared Afterglow Candidate
  79. GRB041219, BVRcIc field calibration
  80. GRB 041219: Infrared Afterglow Candidate
  81. GRB041218, BVRcIc field calibration
  82. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  83. GRB 041219 - A long GRB detected by INTEGRAL
  84. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  85. GRB 041217: PROMPT Observations
  86. GRB 041217: LCO40 Optical Observations and Possible Candidates
  87. GRB 041218 - A long GRB detected by integral
  88. GRB041217: NIR and optical observations with REM
  89. GRB041217: Infrared Observations
  90. GRB041217: The First GRB Located On-Board Swift
  91. GRB041211: Faulkes Telescope continued optical monitoring
  92. Optical Transient in Lynx not a GRB
  93. Optical transient (GRB?) in Lynx
  94. GRB041211: RAPTOR observations
  95. GRB041211: Ashra Prototype optical observation
  96. GRB041211, BVRcIc field calibration
  97. GRB041211,optical observation
  98. GRB 041211: Infrared Observations
  99. GRB 041211: KAIT observations
  100. GRB 041211: Optical follow-up in East Asian region

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