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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. X-ray rich GRB011030: BeppoSAX refined positions
  2. BeppoSAX ALERT: Possible X-ray rich GRB011030
  3. GRB 010921: Possible supernova component
  4. GRB011019: NEAT Optical Observations
  5. GRB011019: ROTSE-III optical observations
  6. GRB010921, optical observation at early time
  7. GRB 010921, I-band observations
  8. GRB011019: Optical observations
  9. GRB011019, optical observations -- correction
  10. GRB011019, optical observations
  11. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  12. GRB010921: Spectroscopy of the Host Galaxy
  13. GRB 010921: The afterglow of HETE #1761
  14. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  15. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  16. GRB010923 as seen by BeppoSAX GRBM
  17. GRB010928(=H1770): Localization of a Long GRB by HETE
  18. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  19. GRB010921, negative optical observations
  20. GRB010921 field photometry
  21. GRB010921 Optical Observations
  22. GRB 010921 DPOSS Images Available
  23. IPN triangulation of GRB010921 (=H1761)
  24. H1761: A Bright GRB Detected by HETE
  25. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  26. HETE Trigger #1760 (GRB 010920B?): a new optical source
  27. HETE Trigger #1759 (GRB 010920?) optical observations
  28. GRB001109, Host Galaxy Astrometry
  29. GRB000926, Host Galaxy Observations
  30. GRB001109, Host Galaxy Spectroscopic Observations
  31. Probable SGR or Short Duration GRB Detected by HETE
  32. GRB000926 Host Galaxy Observations
  33. GRB 010222: HST observations -- host galaxy and late-time decay
  34. BeppoSAX/GRBM detection of GRB 010801
  35. GCN and HETE status
  36. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  37. BeppoSAX/GRBM detection of GRB010728
  38. GRB 010222 - WHT BVRI images
  39. SGR1900+14 burst seen by HETE: BeppoSAX data
  40. GRB 010629 Optical Observations
  41. GRB010629: Optical Observations
  42. SGR1900+14: High Fluence Burst Localized by HETE
  43. GRB010629, optical observations
  44. IPN triangulation of GRB010629
  45. GRB010629: A Burst Localized by HETE
  46. SGR1900+14: Second Burst Localized by HETE
  47. SGR1900+14: A Burst Localized by HETE
  48. Possible burst from SGR1806-20
  49. IPN detection of SGR1900+14
  50. SGR1806-20: A Second, Intense Burst Localized by HETE
  51. GRB 00630: Host Galaxy
  52. SGR1806-20: Localization by HETE
  53. IPN triangulation of GRB010613
  54. IPN triangulation of GRB010612
  55. IPN triangulation of GRB010612
  56. HETE Fully-Automated GCN Notices
  57. GRB000301C: Late-time HST/STIS observation
  58. GRB010518: a faint BeppoSAX detection
  59. GRB000418: HST/STIS Second-epoch Observations
  60. X-ray precursors to the large flare from SGR 1900+14
  61. GRB010214, optical observations
  62. GRB010427, Gamma Ray Observations
  63. SGR 1900+14: No evidence of extended X-ray emission
  64. SGR 1900+14 : RXTE observations
  65. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  66. SGR1900+14 - correction
  67. SGR1900+14
  68. SGR 1900+14: Correction to GCN 1049
  69. GRB 010222 /corrections to VBT data
  70. Millimeter observation of SGR 1900+14
  71. SGR 1900+14: Detection of extended X-ray emission
  72. Chandra Observations of SGR 1900+14
  73. SGR 1900+14, Chandra observations
  74. Chandra Observations of SGR 1900+14
  75. Possible precursor to the SGR1900+14 giant burst
  76. SGR1900+14, I-band observations
  77. IPN Triangulation of the Giant Flare from SGR1900+14
  78. GRB010412, field photometry
  79. Giant flare from SGR1900+14
  80. GRB 010326b Optical Observations
  81. GRB010412: Optical observations
  82. GRB010412: Optical observations
  83. GRB010412: BeppoSAX GRBM and WFC observations
  84. IPN Triangulation of GRB010412
  85. GRB010412: refined positions from BeppoSAX
  86. BeppoSAX GRB: extension of BSAX operations upto April 30, 2002
  87. BeppoSAX GRB ALERT: GRB010412
  88. GRB Observation Report
  89. GRB010324, revised field photometry
  90. REVISED LOCATION OF GRB010326A
  91. GRB 980326: Late-time HST/STIS observations
  92. GRB010324, field photometry
  93. GRB010326B, field photometry
  94. GRB010326, field photometry
  95. GRB010220, field photometry
  96. Further Optical Observations of GRB 010324
  97. GRB010222, CXO X-ray observations
  98. GRB 010326A: Further optical observations
  99. GRB010324: BeppoSAX/GRBM data
  100. GRB 010326B: Optical observations

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