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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"

36145 results found.

  1. GRB 050306: Possible X-ray Afterglow Position from the Swift
  2. Swift trigger 107518: optical observation
  3. GRB 050306: TAROT optical observations
  4. GRB 050306,optical observation
  5. GRB 050306: Swift-BAT detection of a long burst
  6. GRB 050126: Confirmation of the NIR afterglow candidate
  7. PROMPT VRcIc Observations of GRB 050223
  8. XRF/GRB 050215B: Radio Observations
  9. XMM-Newton Images of GRB 050223
  10. GRB 050219b: candidate NIR afterglow
  11. IBAS GRB Alert #2321
  12. GRB 050223: optical observations
  13. INTEGRAL detection of GRB 050223
  14. GRB 050223 : Planned XMM-Newton observation
  15. GRB050223: ROTSE-III Optical Observations
  16. GRB 050223 Swift/BAT detection of a burst
  17. GRB 050223: Swift XRT Position
  18. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  19. GRB 050219b: CORRECTION to refined XRT position
  20. GRB 050219a: Optical observations from LCO
  21. GRB 050219b: Optical and near-IR observations from LCO
  22. GRB 050219b: Refined XRT position
  23. GRB 050219b: Swift-BAT detection of a burst
  24. GRB 050219b: CORRECTION: Swift XRT Position
  25. GRB 050219b: Swift XRT Position
  26. GRB 050219a, optical observations
  27. GRB 050219a: Refined XRT position
  28. GRB 050219: Swift-BAT detection of a burst
  29. GRB050215b: Swift UVOT Detection of Afterglow Emission
  30. GRB 050219: Prompt X-ray position
  31. GRB 050215B: Radio Observations
  32. GRB 050215b: XRT confirmation of IR afterglow candidate
  33. GRB050215b: P60 Optical Observations
  34. GRB 050215b: Swift XRT Source Variability
  35. GRB 050215B: candidate afterglow
  36. GRB 050215b : Lulin follow-up observation
  37. GRB 050215b, BOOTES-2 simultaneous optical observations
  38. GRB 050215B: UKIRT K-band imaging
  39. GRB 050215b: Swift XRT Observations
  40. GRB 050215b, BOOTES-1B optical limit
  41. GRB050215A: ROTSE-III Optical Observations
  42. GRB050209: TAROT optical observations
  43. GRB 050209(=U11568): Duration and spectrum
  44. short/hard GRB 050202, optical observations
  45. GRB050209: REM optical observations
  46. GRB 050209 I-band observation
  47. GRB 050209 Optical observations
  48. GRB050209: P60 Optical Observations
  49. GRB050209 (=U11568): A Long GRB Detected by HETE
  50. GRB 050209: Optical observation
  51. GRB 050128: Radio observations
  52. Further analysis of the short Swift-BAT GRB 050202
  53. GRB 050202: Second epoch radio observations
  54. GRB 050129: Optical observations
  55. GRB050202: Radio Observations
  56. GRB 050202: Optical observations with LCO40
  57. GRB 050202: Short burst detected by Swift-BAT
  58. GRB 050128 Optical observation with REM
  59. GRB 050129: a weak long GRB detected with INTEGRAL
  60. GRB050128: Faulkes Telescope South observations
  61. GRB 050124: Radio Observations
  62. GRB 050128: near-infrared observations with REM
  63. GRB050128,optical observations
  64. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  65. GRB 050126: Radio Observations
  66. GRB050128 Swift-BAT observations
  67. GRB 050128: Swift XRT prompt afterglow position
  68. GRB 050124: K-band afterglow observations
  69. GRB050126: MASTER optical limit for KECK OT
  70. GRB050126: MASTER optical observations
  71. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  72. GRB 050126: Prompt XRT detection and localization
  73. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  74. GRB 050124, SMARTS optical/IR observations
  75. GRB 050117a: Radio Observations
  76. GRB 050124 I-band observation
  77. GRB 050124: NIR Candidates from Keck/NIRC
  78. GRB050124,optical observation
  79. GRB 050124 : Lulin R-band follow-up observation
  80. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  81. GRB 050123 : I-band follow-up observation
  82. GRB050123: optical limit 1.8h before GRB
  83. GRB050123,optical observation
  84. GRB 050123: KAIT observations
  85. GRB050123: P60 Observations
  86. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  87. CFHTLS optical transient unlikely to be a GRB
  88. Unusual optical transient (GRB ???)
  89. GRB050117a: Radio Observations
  90. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  91. GRB 050117, I-band observations
  92. GRB 050117: Optical observation
  93. GRB050117: Refined XRT position
  94. GRB050117: MASTER optical observations
  95. MASTER:GRB050117 SWIFT
  96. GRB050117: Swift-BAT detection of a long multi-peaked burst
  97. Triangulation of Short Hard GRB050112 (large error box)
  98. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  99. SGR 1806-20 and extragalactic short-duration GRBs
  100. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars

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