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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"

28041 results found.

  1. GRB050316: MASTER optical observations
  2. GRB 050315: Swift-BAT further refined analysis
  3. GRB 050315 I-band observations
  4. GRB050315: Radio afterglow
  5. GRB050315: Swift-BAT Refined analysis
  6. Non-detection of GRB050315 in ATCA Radio Observations
  7. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  8. GRB 050315: Early Observations with Swift/UVOT
  9. GRB 050306: Radio Observations
  10. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  11. GRB 050306: optical afterglow
  12. Swift-BAT trigger 107873: No Swift XRT counterpart
  13. GRB 050306: Confirmation of X-ray afterglow
  14. GRB 050306: further TAROT optical data
  15. GRB050309: Early optical limit from P60
  16. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  17. GRB 050309 : Lulin R-band observation
  18. Swift 107873: P60 Optical Observations
  19. GRB 050306: R-band observations
  20. GRB 050306: REM optical-infrared observations
  21. GRB 050306: Possible X-ray Afterglow Position from the Swift
  22. GRB 050306: TAROT optical observations
  23. GRB 050306,optical observation
  24. Ongoing activity of SGR 1806-20 after the giant flare
  25. GRB050215B: Late-Time Swift UVOT Observations
  26. PROMPT VRcIc Observations of GRB 050223
  27. XRF/GRB 050215B: Radio Observations
  28. XMM-Newton Images of GRB 050223
  29. GRB 050219b: candidate NIR afterglow
  30. Confirmed XRF nature for GRB050215b
  31. GRB050223 XMM-Newton observation
  32. INTEGRAL detection of GRB 050223
  33. GRB050223: ROTSE-III Optical Observations
  34. GRB 050223 Swift/BAT detection of a burst
  35. GRB 050223: Swift XRT Position
  36. HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
  37. GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
  38. GRB 050219a: Optical observations from LCO
  39. GRB 050219b: Optical and near-IR observations from LCO
  40. GRB 050219b: Swift-BAT detection of a burst
  41. GRB 050219b: CORRECTION: Swift XRT Position
  42. GRB 050219b: Swift XRT Position
  43. GRB 050219: Swift-BAT detection of a burst
  44. GRB 050215b: XRT confirmation of IR afterglow candidate
  45. GRB050215b: P60 Optical Observations
  46. GRB 050215b: Swift XRT Source Variability
  47. GRB 050215B: candidate afterglow
  48. GRB 050215b : Lulin follow-up observation
  49. GRB 050215b, BOOTES-2 simultaneous optical observations
  50. GRB050215A: ROTSE-III Optical Observations
  51. GRB050209: TAROT optical observations
  52. GRB 050209(=U11568): Duration and spectrum
  53. GRB050209: REM optical observations
  54. GRB 050209 I-band observation
  55. GRB 050209 Optical observations
  56. GRB050209: P60 Optical Observations
  57. GRB 050128: Radio observations
  58. Further analysis of the short Swift-BAT GRB 050202
  59. GRB 050202: Short burst detected by Swift-BAT
  60. GRB 050128 Optical observation with REM
  61. SGR1806-20: Swift-BAT detection of a large normal burst
  62. GRB 050128: near-infrared observations with REM
  63. GRB050128,optical observations
  64. GRB050128 Swift-BAT observations
  65. GRB 050128: Swift XRT prompt afterglow position
  66. GRB050126: MASTER optical limit for KECK OT
  67. GRB050126: Burst Parameters Measured by BAT
  68. GRB050126: MASTER optical observations
  69. GRB 050124 I-band observation
  70. GRB050124,optical observation
  71. GRB 050124 : Lulin R-band follow-up observation
  72. GRB050124: Updated Swift XRT Position and Fluxes
  73. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  74. GRB050124: Refined BAT position, spectral and fluence information
  75. GRB 050123 : I-band follow-up observation
  76. GRB050123,optical observation
  77. GRB 050123: KAIT observations
  78. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  79. GRB050117: Refined XRT position
  80. GRB050117: MASTER optical observations
  81. MASTER:GRB050117 SWIFT
  82. GRB050117: Swift XRT Position
  83. Triangulation of Short Hard GRB050112 (large error box)
  84. SGR 1806-20: Further VLA Observations
  85. SGR1806-20: Swift-BAT observations of two additional bursts
  86. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  87. Further VLA observations of SGR 1806-20
  88. SGR 1806-20 and extragalactic short-duration GRBs
  89. Further ATCA observations of SGR 1806-20
  90. Fourth Epoch VLA observations of SGR 1806-20
  91. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  92. ATCA observations of SGR 1806-20
  93. SGR 1806-20, RHESSI observations of the 041227 giant flare
  94. Third epoch observations of SGR 1806-20 with VLA
  95. Second Epoch VLA observations of SGR 1806-20
  96. Second-epoch VLA observations of SGR 1806-20
  97. SGR1806 VLA Observations
  98. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  99. GRB 041217: Optical observations
  100. GRB041228: Swift-BAT detection of a burst

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