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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"

19530 results found.

  1. GRB 050315: Swift-BAT further refined analysis
  2. GRB050315: Swift-BAT Refined analysis
  3. Non-detection of GRB050315 in ATCA Radio Observations
  4. GRB 050315: Swift XRT Position
  5. GRB 050315: Early Observations with Swift/UVOT
  6. Swift-BAT detection of GRB 050315
  7. GRB050223: No XMM-Newton OM detection of afterglow emission
  8. GRB050309: CONCAM pre-trigger and trigger coincident optical
  9. GRB 050126: Redshift determination
  10. Swift-BAT trigger 107873: No Swift XRT counterpart
  11. GRB 050306: Confirmation of X-ray afterglow
  12. GRB 050309, Early optical limits from RAPTOR
  13. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  14. GRB 050309 : Lulin R-band observation
  15. Swift 107873: P60 Optical Observations
  16. GRB 050306: CORRECTION to date of observation
  17. GRB 050306: No Swift UVOT Optical Counterpart Detected
  18. GRB 050306: Possible X-ray Afterglow Position from the Swift
  19. Swift trigger 107518: optical observation
  20. GRB 050306,optical observation
  21. GRB 050306: Swift-BAT detection of a long burst
  22. GRB050215B: Late-Time Swift UVOT Observations
  23. PROMPT VRcIc Observations of GRB 050223
  24. GRB 050223: optical observations
  25. GRB050223 XMM-Newton observation
  26. INTEGRAL detection of GRB 050223
  27. GRB050223: No Swift UVOT Detection of Afterglow Emission
  28. GRB050223: ROTSE-III Optical Observations
  29. GRB 050223 Swift/BAT detection of a burst
  30. GRB 050223: Swift XRT Position
  31. GRB050219b: CORRECTION to time of UVOT observations
  32. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  33. GRB 050219b: CORRECTION to refined XRT position
  34. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  35. GRB 050219b: Refined XRT position
  36. GRB 050219b: Swift-BAT detection of a burst
  37. GRB 050219b: CORRECTION: Swift XRT Position
  38. GRB 050219b: Swift XRT Position
  39. GRB 050219a, optical observations
  40. GRB 050219a: Refined XRT position
  41. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  42. GRB 050219: Swift-BAT detection of a burst
  43. GRB050215b: Swift UVOT Detection of Afterglow Emission
  44. GRB 050219: Prompt X-ray position
  45. GRB 050215b: XRT confirmation of IR afterglow candidate
  46. GRB050215b: P60 Optical Observations
  47. GRB 050215b: Swift XRT Source Variability
  48. GRB 050215B: candidate afterglow
  49. GRB 050215b : Lulin follow-up observation
  50. GRB 050215b, BOOTES-2 simultaneous optical observations
  51. GRB 050215B: UKIRT K-band imaging
  52. GRB 050215b: Swift XRT Observations
  53. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  54. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  55. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  56. GRB050215B: ROTSE-III optical observations
  57. GRB050215A: ROTSE-III Optical Observations
  58. short/hard GRB 050202, optical observations
  59. GRB 050128: Radio observations
  60. Further analysis of the short Swift-BAT GRB 050202
  61. GRB 050202: Second epoch radio observations
  62. GRB050202: Radio Observations
  63. GRB 050202: Short burst detected by Swift-BAT
  64. SGR1806-20: Swift-BAT detection of a large normal burst
  65. GRB050128: Faulkes Telescope South observations
  66. GRB050128,optical observations
  67. GRB050126: Updated Swift XRT Position
  68. GRB 050126: Radio Observations
  69. GRB050128 Swift-BAT observations
  70. GRB 050128: Swift XRT prompt afterglow position
  71. GRB 050124: K-band afterglow observations
  72. GRB050126: MASTER optical limit for KECK OT
  73. GRB050126: Burst Parameters Measured by BAT
  74. GRB050126: MASTER optical observations
  75. GRB 050126: Prompt XRT detection and localization
  76. GRB050124: No Swift UVOT Detection of Afterglow Emission
  77. GRB 050117a: Radio Observations
  78. GRB050124,optical observation
  79. GRB050124: Updated Swift XRT Position and Fluxes
  80. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  81. GRB050124: Refined BAT position, spectral and fluence information
  82. GRB050124: Swift-BAT position of a double-peaked burst
  83. GRB050117a: Radio Observations
  84. GRB050117a: Refined analysis
  85. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  86. GRB050117b: Swift-BAT detection of a weak burst
  87. GRB050117: optical observation
  88. GRB 050117, I-band observations
  89. GRB 050117: Optical observation
  90. GRB050117: Refined XRT position
  91. GRB050117: MASTER optical observations
  92. MASTER:GRB050117 SWIFT
  93. GRB050117: Swift-BAT detection of a long multi-peaked burst
  94. GRB050117: Swift XRT Position
  95. SGR1806-20: Swift-BAT observations of two additional bursts
  96. SGR 1806-20, RHESSI observations of the 041227 giant flare
  97. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  98. GRB 041217: Optical observations
  99. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  100. GRB041228: ROTSE-III Optical Observations

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