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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 050306: optical afterglow
  2. GRB 050126: Redshift determination
  3. Swift-BAT trigger 107873: No Swift XRT counterpart
  4. GRB 050306: Confirmation of X-ray afterglow
  5. GRB 050309, Early optical limits from RAPTOR
  6. GRB 050306: further TAROT optical data
  7. GRB050309: Early optical limit from P60
  8. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  9. GRB 050309 : Lulin R-band observation
  10. Swift 107873: P60 Optical Observations
  11. GRB 050306: CORRECTION to date of observation
  12. GRB 050306: R-band observations
  13. GRB 050306: No Swift UVOT Optical Counterpart Detected
  14. GRB 050306: REM optical-infrared observations
  15. GRB 050306: Possible X-ray Afterglow Position from the Swift
  16. Swift trigger 107518: optical observation
  17. GRB 050306: TAROT optical observations
  18. GRB 050306,optical observation
  19. GRB 050306: Swift-BAT detection of a long burst
  20. Ongoing activity of SGR 1806-20 after the giant flare
  21. GRB050215B: Late-Time Swift UVOT Observations
  22. GRB 050126: Confirmation of the NIR afterglow candidate
  23. PROMPT VRcIc Observations of GRB 050223
  24. XRF/GRB 050215B: Radio Observations
  25. XMM-Newton Images of GRB 050223
  26. GRB 050219b: candidate NIR afterglow
  27. IBAS GRB Alert #2321
  28. Confirmed XRF nature for GRB050215b
  29. GRB 050223: optical observations
  30. GRB050223 XMM-Newton observation
  31. INTEGRAL detection of GRB 050223
  32. GRB 050223 : Planned XMM-Newton observation
  33. GRB050223: No Swift UVOT Detection of Afterglow Emission
  34. GRB050223: ROTSE-III Optical Observations
  35. GRB 050223 Swift/BAT detection of a burst
  36. GRB 050223: Swift XRT Position
  37. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  38. GRB050219b: CORRECTION to time of UVOT observations
  39. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  40. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  41. GRB 050219b: CORRECTION to refined XRT position
  42. GRB 050219a: Optical observations from LCO
  43. GRB 050219b: Optical and near-IR observations from LCO
  44. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  45. GRB 050219b: Refined XRT position
  46. GRB 050219b: Swift-BAT detection of a burst
  47. GRB 050219b: CORRECTION: Swift XRT Position
  48. GRB 050219b: Swift XRT Position
  49. GRB 050219a, optical observations
  50. GRB 050219a: Refined XRT position
  51. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  52. GRB 050219: Swift-BAT detection of a burst
  53. GRB050215b: Swift UVOT Detection of Afterglow Emission
  54. GRB 050219: Prompt X-ray position
  55. GRB 050215B: Radio Observations
  56. GRB 050215b: XRT confirmation of IR afterglow candidate
  57. GRB050215b: P60 Optical Observations
  58. GRB 050215b: Swift XRT Source Variability
  59. GRB 050215B: candidate afterglow
  60. GRB 050215b : Lulin follow-up observation
  61. GRB 050215b, BOOTES-2 simultaneous optical observations
  62. GRB 050215B: UKIRT K-band imaging
  63. GRB 050215b: Swift XRT Observations
  64. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  65. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  66. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  67. GRB 050215b, BOOTES-1B optical limit
  68. GRB050215B: ROTSE-III optical observations
  69. GRB050215A: ROTSE-III Optical Observations
  70. GRB050209: TAROT optical observations
  71. GRB 050209(=U11568): Duration and spectrum
  72. short/hard GRB 050202, optical observations
  73. GRB050209: REM optical observations
  74. GRB 050209 I-band observation
  75. GRB 050209 Optical observations
  76. GRB050209: P60 Optical Observations
  77. GRB050209 (=U11568): A Long GRB Detected by HETE
  78. GRB 050209: Optical observation
  79. GRB 050128: Radio observations
  80. Further analysis of the short Swift-BAT GRB 050202
  81. GRB 050202: Second epoch radio observations
  82. GRB 050129: Optical observations
  83. GRB050202: Radio Observations
  84. GRB 050202: Optical observations with LCO40
  85. GRB 050202: Short burst detected by Swift-BAT
  86. GRB 050128 Optical observation with REM
  87. GRB 050129: a weak long GRB detected with INTEGRAL
  88. SGR1806-20: Swift-BAT detection of a large normal burst
  89. GRB050128: Faulkes Telescope South observations
  90. GRB 050124: Radio Observations
  91. GRB 050128: near-infrared observations with REM
  92. GRB050128,optical observations
  93. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  94. GRB050126: Updated Swift XRT Position
  95. SGR 1806-20: GMRT results at 240 MHz band.
  96. SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
  97. GRB 050126: Radio Observations
  98. GRB050128 Swift-BAT observations
  99. GRB 050128: Swift XRT prompt afterglow position
  100. HETE #3667: P60 Observations

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