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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"

27391 results found.

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

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