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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"

34311 results found.

  1. GRB050215b: Swift UVOT Detection of Afterglow Emission
  2. GRB 050219: Prompt X-ray position
  3. GRB 050215B: Radio Observations
  4. GRB 050215b: XRT confirmation of IR afterglow candidate
  5. GRB050215b: P60 Optical Observations
  6. GRB 050215b: Swift XRT Source Variability
  7. GRB 050215B: candidate afterglow
  8. GRB 050215b : Lulin follow-up observation
  9. GRB 050215b, BOOTES-2 simultaneous optical observations
  10. GRB 050215B: UKIRT K-band imaging
  11. GRB 050215b: Swift XRT Observations
  12. GRB 050215b, BOOTES-1B optical limit
  13. GRB050215A: ROTSE-III Optical Observations
  14. GRB050209: TAROT optical observations
  15. GRB 050209(=U11568): Duration and spectrum
  16. short/hard GRB 050202, optical observations
  17. GRB050209: REM optical observations
  18. GRB 050209 I-band observation
  19. GRB 050209 Optical observations
  20. GRB050209: P60 Optical Observations
  21. GRB050209 (=U11568): A Long GRB Detected by HETE
  22. GRB 050209: Optical observation
  23. GRB 050128: Radio observations
  24. Further analysis of the short Swift-BAT GRB 050202
  25. GRB 050202: Second epoch radio observations
  26. GRB 050129: Optical observations
  27. GRB050202: Radio Observations
  28. GRB 050202: Optical observations with LCO40
  29. GRB 050202: Short burst detected by Swift-BAT
  30. GRB 050128 Optical observation with REM
  31. GRB 050129: a weak long GRB detected with INTEGRAL
  32. GRB050128: Faulkes Telescope South observations
  33. GRB 050124: Radio Observations
  34. GRB 050128: near-infrared observations with REM
  35. GRB050128,optical observations
  36. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  37. GRB 050126: Radio Observations
  38. GRB050128 Swift-BAT observations
  39. GRB 050128: Swift XRT prompt afterglow position
  40. GRB 050124: K-band afterglow observations
  41. GRB050126: MASTER optical limit for KECK OT
  42. GRB050126: MASTER optical observations
  43. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  44. GRB 050126: Prompt XRT detection and localization
  45. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  46. GRB 050124, SMARTS optical/IR observations
  47. GRB 050117a: Radio Observations
  48. GRB 050124 I-band observation
  49. GRB 050124: NIR Candidates from Keck/NIRC
  50. GRB050124,optical observation
  51. GRB 050124 : Lulin R-band follow-up observation
  52. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  53. GRB 050123 : I-band follow-up observation
  54. GRB050123: optical limit 1.8h before GRB
  55. GRB050123,optical observation
  56. GRB 050123: KAIT observations
  57. GRB050123: P60 Observations
  58. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  59. CFHTLS optical transient unlikely to be a GRB
  60. Unusual optical transient (GRB ???)
  61. GRB050117a: Radio Observations
  62. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  63. GRB 050117, I-band observations
  64. GRB 050117: Optical observation
  65. GRB050117: Refined XRT position
  66. GRB050117: MASTER optical observations
  67. MASTER:GRB050117 SWIFT
  68. GRB050117: Swift-BAT detection of a long multi-peaked burst
  69. Triangulation of Short Hard GRB050112 (large error box)
  70. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  71. SGR 1806-20 and extragalactic short-duration GRBs
  72. SGR 1806-20: Temporal and Spectral behavior of radio transient
  73. SGR 1806-20, RHESSI observations of the 041227 giant flare
  74. SGR1806: Detection of a Sudden Ionospheric Disturbance
  75. GRB 041217: Optical observations
  76. GRB041219, early time observations
  77. IPN localization of giant flare from SGR1806-20
  78. GRB041219; RXTE ASM Observations
  79. NIR Observations of GRB 041219
  80. GRB041223: decay of the afterglow
  81. GRB 041224: near-infrared observations with REM
  82. GRB 041223: XRT afterglow spectrum and light curve
  83. GRB 041223 Fluence measured by Swift-BAT
  84. GRB041223: optical and NIR observations with REM
  85. GRB 041219: TAROT optical observations
  86. GRB 041218: TAROT optical observations
  87. GRB 041223: J-band observations of the afterglow
  88. GRB 041223: Detection of Optical Transient with LCO40
  89. GRB 041219c: PROMPT Observations
  90. GRB 041218: optical observations
  91. GRB 041219: Second Epoch WSRT Radio Observations
  92. GRB 041219: WSRT Radio Afterglow Detection
  93. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  94. GRB 041218: Optical observations
  95. GRB 041219 : optical follow-up observations
  96. Deep RAPTOR observations during GRB 041219
  97. GRB 041218 Optical Observations
  98. GRB 041219 Optical Observations
  99. GRB041219c: Third Burst in One Day from Swift-BAT
  100. GRB041219: Optical Afterglow Detection

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