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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"
  1. GRB 050309 : Lulin R-band observation
  2. Swift 107873: P60 Optical Observations
  3. GRB 050306: CORRECTION to date of observation
  4. GRB 050306: R-band observations
  5. GRB 050306: No Swift UVOT Optical Counterpart Detected
  6. GRB 050306: REM optical-infrared observations
  7. GRB 050306: Possible X-ray Afterglow Position from the Swift
  8. Swift trigger 107518: optical observation
  9. GRB 050306: TAROT optical observations
  10. GRB 050306,optical observation
  11. GRB 050306: Swift-BAT detection of a long burst
  12. Ongoing activity of SGR 1806-20 after the giant flare
  13. GRB050215B: Late-Time Swift UVOT Observations
  14. GRB 050126: Confirmation of the NIR afterglow candidate
  15. PROMPT VRcIc Observations of GRB 050223
  16. XRF/GRB 050215B: Radio Observations
  17. XMM-Newton Images of GRB 050223
  18. GRB 050219b: candidate NIR afterglow
  19. IBAS GRB Alert #2321
  20. Confirmed XRF nature for GRB050215b
  21. GRB 050223: optical observations
  22. GRB050223 XMM-Newton observation
  23. INTEGRAL detection of GRB 050223
  24. GRB 050223 : Planned XMM-Newton observation
  25. GRB050223: No Swift UVOT Detection of Afterglow Emission
  26. GRB050223: ROTSE-III Optical Observations
  27. GRB 050223 Swift/BAT detection of a burst
  28. GRB 050223: Swift XRT Position
  29. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  30. GRB050219b: CORRECTION to time of UVOT observations
  31. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  32. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  33. GRB 050219b: CORRECTION to refined XRT position
  34. GRB 050219a: Optical observations from LCO
  35. GRB 050219b: Optical and near-IR observations from LCO
  36. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  37. GRB 050219b: Refined XRT position
  38. GRB 050219b: Swift-BAT detection of a burst
  39. GRB 050219b: CORRECTION: Swift XRT Position
  40. GRB 050219b: Swift XRT Position
  41. GRB 050219a, optical observations
  42. GRB 050219a: Refined XRT position
  43. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  44. GRB 050219: Swift-BAT detection of a burst
  45. GRB050215b: Swift UVOT Detection of Afterglow Emission
  46. GRB 050219: Prompt X-ray position
  47. GRB 050215B: Radio Observations
  48. GRB 050215b: XRT confirmation of IR afterglow candidate
  49. GRB050215b: P60 Optical Observations
  50. GRB 050215b: Swift XRT Source Variability
  51. GRB 050215B: candidate afterglow
  52. GRB 050215b : Lulin follow-up observation
  53. GRB 050215b, BOOTES-2 simultaneous optical observations
  54. GRB 050215B: UKIRT K-band imaging
  55. GRB 050215b: Swift XRT Observations
  56. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  57. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  58. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  59. GRB 050215b, BOOTES-1B optical limit
  60. GRB050215B: ROTSE-III optical observations
  61. GRB050215A: ROTSE-III Optical Observations
  62. GRB050209: TAROT optical observations
  63. GRB 050209(=U11568): Duration and spectrum
  64. short/hard GRB 050202, optical observations
  65. GRB050209: REM optical observations
  66. GRB 050209 I-band observation
  67. GRB 050209 Optical observations
  68. GRB050209: P60 Optical Observations
  69. GRB050209 (=U11568): A Long GRB Detected by HETE
  70. GRB 050209: Optical observation
  71. GRB 050128: Radio observations
  72. Further analysis of the short Swift-BAT GRB 050202
  73. GRB 050202: Second epoch radio observations
  74. GRB 050129: Optical observations
  75. GRB050202: Radio Observations
  76. GRB 050202: Optical observations with LCO40
  77. GRB 050202: Short burst detected by Swift-BAT
  78. GRB 050128 Optical observation with REM
  79. GRB 050129: a weak long GRB detected with INTEGRAL
  80. SGR1806-20: Swift-BAT detection of a large normal burst
  81. GRB050128: Faulkes Telescope South observations
  82. GRB 050124: Radio Observations
  83. GRB 050128: near-infrared observations with REM
  84. GRB050128,optical observations
  85. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  86. GRB050126: Updated Swift XRT Position
  87. SGR 1806-20: GMRT results at 240 MHz band.
  88. SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
  89. GRB 050126: Radio Observations
  90. GRB050128 Swift-BAT observations
  91. GRB 050128: Swift XRT prompt afterglow position
  92. HETE #3667: P60 Observations
  93. GRB 050124: K-band afterglow observations
  94. GRB050126: MASTER optical limit for KECK OT
  95. GRB050126: Burst Parameters Measured by BAT
  96. GRB050126: MASTER optical observations
  97. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  98. GRB 050126: Prompt XRT detection and localization
  99. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  100. GRB050124: No Swift UVOT Detection of Afterglow Emission

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