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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"

34058 results found.

  1. Swift 107873: P60 Optical Observations
  2. GRB 050306: CORRECTION to date of observation
  3. GRB 050306: R-band observations
  4. GRB 050306: No Swift UVOT Optical Counterpart Detected
  5. GRB 050306: REM optical-infrared observations
  6. GRB 050306: Possible X-ray Afterglow Position from the Swift
  7. Swift trigger 107518: optical observation
  8. GRB 050306: TAROT optical observations
  9. GRB 050306,optical observation
  10. GRB 050306: Swift-BAT detection of a long burst
  11. GRB 050126: Confirmation of the NIR afterglow candidate
  12. PROMPT VRcIc Observations of GRB 050223
  13. XRF/GRB 050215B: Radio Observations
  14. XMM-Newton Images of GRB 050223
  15. GRB 050219b: candidate NIR afterglow
  16. IBAS GRB Alert #2321
  17. GRB 050223: optical observations
  18. INTEGRAL detection of GRB 050223
  19. GRB 050223 : Planned XMM-Newton observation
  20. GRB050223: ROTSE-III Optical Observations
  21. GRB 050223 Swift/BAT detection of a burst
  22. GRB 050223: Swift XRT Position
  23. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  24. GRB 050219b: CORRECTION to refined XRT position
  25. GRB 050219a: Optical observations from LCO
  26. GRB 050219b: Optical and near-IR observations from LCO
  27. GRB 050219b: Refined XRT position
  28. GRB 050219b: Swift-BAT detection of a burst
  29. GRB 050219b: CORRECTION: Swift XRT Position
  30. GRB 050219b: Swift XRT Position
  31. GRB 050219a, optical observations
  32. GRB 050219a: Refined XRT position
  33. GRB 050219: Swift-BAT detection of a burst
  34. GRB050215b: Swift UVOT Detection of Afterglow Emission
  35. GRB 050219: Prompt X-ray position
  36. GRB 050215B: Radio Observations
  37. GRB 050215b: XRT confirmation of IR afterglow candidate
  38. GRB050215b: P60 Optical Observations
  39. GRB 050215b: Swift XRT Source Variability
  40. GRB 050215B: candidate afterglow
  41. GRB 050215b : Lulin follow-up observation
  42. GRB 050215b, BOOTES-2 simultaneous optical observations
  43. GRB 050215B: UKIRT K-band imaging
  44. GRB 050215b: Swift XRT Observations
  45. GRB 050215b, BOOTES-1B optical limit
  46. GRB050215A: ROTSE-III Optical Observations
  47. GRB050209: TAROT optical observations
  48. GRB 050209(=U11568): Duration and spectrum
  49. short/hard GRB 050202, optical observations
  50. GRB050209: REM optical observations
  51. GRB 050209 I-band observation
  52. GRB 050209 Optical observations
  53. GRB050209: P60 Optical Observations
  54. GRB050209 (=U11568): A Long GRB Detected by HETE
  55. GRB 050209: Optical observation
  56. GRB 050128: Radio observations
  57. Further analysis of the short Swift-BAT GRB 050202
  58. GRB 050202: Second epoch radio observations
  59. GRB 050129: Optical observations
  60. GRB050202: Radio Observations
  61. GRB 050202: Optical observations with LCO40
  62. GRB 050202: Short burst detected by Swift-BAT
  63. GRB 050128 Optical observation with REM
  64. GRB 050129: a weak long GRB detected with INTEGRAL
  65. GRB050128: Faulkes Telescope South observations
  66. GRB 050124: Radio Observations
  67. GRB 050128: near-infrared observations with REM
  68. GRB050128,optical observations
  69. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  70. GRB 050126: Radio Observations
  71. GRB050128 Swift-BAT observations
  72. GRB 050128: Swift XRT prompt afterglow position
  73. GRB 050124: K-band afterglow observations
  74. GRB050126: MASTER optical limit for KECK OT
  75. GRB050126: MASTER optical observations
  76. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  77. GRB 050126: Prompt XRT detection and localization
  78. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  79. GRB 050124, SMARTS optical/IR observations
  80. GRB 050117a: Radio Observations
  81. GRB 050124 I-band observation
  82. GRB 050124: NIR Candidates from Keck/NIRC
  83. GRB050124,optical observation
  84. GRB 050124 : Lulin R-band follow-up observation
  85. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  86. GRB 050123 : I-band follow-up observation
  87. GRB050123: optical limit 1.8h before GRB
  88. GRB050123,optical observation
  89. GRB 050123: KAIT observations
  90. GRB050123: P60 Observations
  91. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  92. CFHTLS optical transient unlikely to be a GRB
  93. Unusual optical transient (GRB ???)
  94. GRB050117a: Radio Observations
  95. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  96. GRB 050117, I-band observations
  97. GRB 050117: Optical observation
  98. GRB050117: Refined XRT position
  99. GRB050117: MASTER optical observations
  100. MASTER:GRB050117 SWIFT

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