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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"

24988 results found.

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

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