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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"

36803 results found.

  1. GRB 050215b, BOOTES-2 simultaneous optical observations
  2. GRB 050215B: UKIRT K-band imaging
  3. GRB 050215b: Swift XRT Observations
  4. GRB 050215b, BOOTES-1B optical limit
  5. GRB050215A: ROTSE-III Optical Observations
  6. GRB050209: TAROT optical observations
  7. GRB 050209(=U11568): Duration and spectrum
  8. short/hard GRB 050202, optical observations
  9. GRB050209: REM optical observations
  10. GRB 050209 I-band observation
  11. GRB 050209 Optical observations
  12. GRB050209: P60 Optical Observations
  13. GRB050209 (=U11568): A Long GRB Detected by HETE
  14. GRB 050209: Optical observation
  15. GRB 050128: Radio observations
  16. Further analysis of the short Swift-BAT GRB 050202
  17. GRB 050202: Second epoch radio observations
  18. GRB 050129: Optical observations
  19. GRB050202: Radio Observations
  20. GRB 050202: Optical observations with LCO40
  21. GRB 050202: Short burst detected by Swift-BAT
  22. GRB 050128 Optical observation with REM
  23. GRB 050129: a weak long GRB detected with INTEGRAL
  24. GRB050128: Faulkes Telescope South observations
  25. GRB 050124: Radio Observations
  26. GRB 050128: near-infrared observations with REM
  27. GRB050128,optical observations
  28. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  29. GRB 050126: Radio Observations
  30. GRB050128 Swift-BAT observations
  31. GRB 050128: Swift XRT prompt afterglow position
  32. GRB 050124: K-band afterglow observations
  33. GRB050126: MASTER optical limit for KECK OT
  34. GRB050126: MASTER optical observations
  35. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  36. GRB 050126: Prompt XRT detection and localization
  37. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  38. GRB 050124, SMARTS optical/IR observations
  39. GRB 050117a: Radio Observations
  40. GRB 050124 I-band observation
  41. GRB 050124: NIR Candidates from Keck/NIRC
  42. GRB050124,optical observation
  43. GRB 050124 : Lulin R-band follow-up observation
  44. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  45. GRB 050123 : I-band follow-up observation
  46. GRB050123: optical limit 1.8h before GRB
  47. GRB050123,optical observation
  48. GRB 050123: KAIT observations
  49. GRB050123: P60 Observations
  50. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  51. CFHTLS optical transient unlikely to be a GRB
  52. Unusual optical transient (GRB ???)
  53. GRB050117a: Radio Observations
  54. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  55. GRB 050117, I-band observations
  56. GRB 050117: Optical observation
  57. GRB050117: Refined XRT position
  58. GRB050117: MASTER optical observations
  59. MASTER:GRB050117 SWIFT
  60. GRB050117: Swift-BAT detection of a long multi-peaked burst
  61. Triangulation of Short Hard GRB050112 (large error box)
  62. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  63. SGR 1806-20 and extragalactic short-duration GRBs
  64. SGR 1806-20: Temporal and Spectral behavior of radio transient
  65. SGR 1806-20, RHESSI observations of the 041227 giant flare
  66. SGR1806: Detection of a Sudden Ionospheric Disturbance
  67. GRB 041217: Optical observations
  68. GRB041219, early time observations
  69. IPN localization of giant flare from SGR1806-20
  70. GRB041219; RXTE ASM Observations
  71. NIR Observations of GRB 041219
  72. GRB041223: decay of the afterglow
  73. GRB 041224: near-infrared observations with REM
  74. GRB 041223: XRT afterglow spectrum and light curve
  75. GRB 041223 Fluence measured by Swift-BAT
  76. GRB041223: optical and NIR observations with REM
  77. GRB 041219: TAROT optical observations
  78. GRB 041218: TAROT optical observations
  79. GRB 041223: J-band observations of the afterglow
  80. GRB 041223: Detection of Optical Transient with LCO40
  81. GRB 041219c: PROMPT Observations
  82. GRB 041218: optical observations
  83. GRB 041219: Second Epoch WSRT Radio Observations
  84. GRB 041219: WSRT Radio Afterglow Detection
  85. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  86. GRB 041218: Optical observations
  87. GRB 041219 : optical follow-up observations
  88. Deep RAPTOR observations during GRB 041219
  89. GRB 041218 Optical Observations
  90. GRB 041219 Optical Observations
  91. GRB041219c: Third Burst in One Day from Swift-BAT
  92. GRB041219: Optical Afterglow Detection
  93. GRB041219: Continued NIR Observations
  94. GRB 041219 ,optical observation
  95. GRB 041219: Radio Afterglow Detection
  96. GRB 041218 : Radio Observations
  97. GRB 041218: R-band optical observations
  98. GRB041219: Confirmed NIR Afterglow
  99. GRB041218: Continued P60 Optical Observations
  100. GRB 041218: Optical Observation

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