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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"

25989 results found.

  1. GRB011030 - further refinement WFC position
  2. GRB 011030, Radio observations
  3. GRB011030: radio search
  4. GRB 010921: Possible supernova component
  5. GRB010921, optical observation at early time
  6. GRB 010921, I-band observations
  7. GRB011019, optical observations
  8. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  9. GRB 010921: The afterglow of HETE #1761
  10. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  11. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  12. GRB010923 as seen by BeppoSAX GRBM
  13. GRB010928(=H1770): Localization of a Long GRB by HETE
  14. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  15. GRB010921, negative optical observations
  16. GRB010921 field photometry
  17. H1761: A Bright GRB Detected by HETE
  18. GRB000926, Host Galaxy Observations
  19. GRB001109, Host Galaxy Spectroscopic Observations
  20. Probable SGR or Short Duration GRB Detected by HETE
  21. GCN and HETE status
  22. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  23. GRB 010222 - WHT BVRI images
  24. SGR1900+14 burst seen by HETE: BeppoSAX data
  25. GRB 010629 Optical Observations
  26. SGR1900+14: High Fluence Burst Localized by HETE
  27. GRB010629, optical observations
  28. GRB010629: A Burst Localized by HETE
  29. SGR1900+14: Second Burst Localized by HETE
  30. SGR1900+14: A Burst Localized by HETE
  31. SGR1806-20: A Second, Intense Burst Localized by HETE
  32. SGR1806-20: Localization by HETE
  33. HETE Fully-Automated GCN Notices
  34. GRB000301C: Late-time HST/STIS observation
  35. GRB010518: a faint BeppoSAX detection
  36. GRB000418: HST/STIS Second-epoch Observations
  37. X-ray precursors to the large flare from SGR 1900+14
  38. GRB010427, Gamma Ray Observations
  39. SGR 1900+14: No evidence of extended X-ray emission
  40. SGR 1900+14 : RXTE observations
  41. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  42. SGR 1900+14: Correction to GCN 1049
  43. GRB 010222 /corrections to VBT data
  44. Millimeter observation of SGR 1900+14
  45. SGR 1900+14: Detection of extended X-ray emission
  46. SGR 1900+14, Chandra observations
  47. SGR1900+14, I-band observations
  48. GRB010412, field photometry
  49. Giant flare from SGR1900+14
  50. GRB 010326b Optical Observations
  51. GRB010412: BeppoSAX GRBM and WFC observations
  52. GRB010324, revised field photometry
  53. REVISED LOCATION OF GRB010326A
  54. GRB 980326: Late-time HST/STIS observations
  55. GRB010324, field photometry
  56. GRB010326B, field photometry
  57. GRB010326, field photometry
  58. GRB010220, field photometry
  59. Further Optical Observations of GRB 010324
  60. GRB010222, CXO X-ray observations
  61. GRB010324, optical observations
  62. GRB010326B: Localization by HETE (2nd GRB for this date)
  63. GRB 010326 optical observations
  64. GRB010326: Refined Localization by HETE
  65. GRB010326: Localization by HETE
  66. Optical Observations of GRB 010324
  67. GRB010222, late-time optical observation
  68. Support extension to the BeppoSAX mission
  69. GRB 010222 - HEGRA GeV/TeV Observations
  70. GRB010222: Chandra X-ray Observatory Observation
  71. GRB010222: Sub-millimeter vanishing act
  72. GRB010222 - Optical observation
  73. GRB 010222, Optical Observations
  74. GRB010222 - Optical observation
  75. GRB 010222: High-Resolution Keck Spectroscopy
  76. GRB 010214, I-band data
  77. GRB 010222
  78. GRB010222 further R-band photometry
  79. GRB010222: R-band data
  80. GRB 010222: Keck Spectroscopy
  81. GRB010214, field photometry
  82. GRB010222, field photometry
  83. GRB010222 further R-band photometry
  84. GRB010222, possible increase of optical decay slope
  85. GRB 010222 Kyoto optical observation
  86. GRB010222 R-BAND OBSERVATION
  87. GRB010214 follow-up from Hanle
  88. GRB 010222: Near-IR Observations
  89. GRB 010222: Optical Observations
  90. GRB010222: Optical decay slope
  91. GRB 010214, Optical Observations
  92. GRB010222, radio observations
  93. GRB010222, optical observations
  94. GRB010222: BeppoSAX/NFI Observations
  95. GRB010214B,Gamma Ray Observations
  96. GRB 010220, simultaneous optical observations
  97. GRB010220: BeppoSAX WFC and GRBM preliminary data
  98. GRB010214, candidate optical afterglow
  99. GRB010214, optical observations
  100. GRB010214: BeppoSAX WFC and GRBM preliminary data

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