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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').
  1. GRB 000131: HST Detection of the Host Galaxy
  2. GRB 970828: HST Observations of the Host Galaxy
  3. GRB010921, optical observation
  4. GRB 011019 optical observation
  5. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  6. GRB011019: Subaru Optical Observations
  7. GRB 011030 I-band Observations
  8. GRB 011030 K-band Observations
  9. GRB010921, optical observations
  10. GRB 011030, WSRT radio observations
  11. GRB011030 - further refinement WFC position
  12. GRB 011030, Radio observations
  13. GRB011030: radio search
  14. GRB 011030, R-band observations
  15. X-ray rich GRB011030: BeppoSAX refined positions
  16. BeppoSAX ALERT: Possible X-ray rich GRB011030
  17. GRB 010921: Possible supernova component
  18. GRB011019: NEAT Optical Observations
  19. GRB011019: ROTSE-III optical observations
  20. GRB010921, optical observation at early time
  21. GRB 010921, I-band observations
  22. GRB011019: Optical observations
  23. GRB011019, optical observations -- correction
  24. GRB011019, optical observations
  25. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  26. GRB010921: Spectroscopy of the Host Galaxy
  27. GRB 010921: The afterglow of HETE #1761
  28. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  29. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  30. GRB010923 as seen by BeppoSAX GRBM
  31. GRB010928(=H1770): Localization of a Long GRB by HETE
  32. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  33. GRB010921, negative optical observations
  34. GRB010921 field photometry
  35. GRB010921 Optical Observations
  36. GRB 010921 DPOSS Images Available
  37. IPN triangulation of GRB010921 (=H1761)
  38. H1761: A Bright GRB Detected by HETE
  39. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  40. HETE Trigger #1760 (GRB 010920B?): a new optical source
  41. HETE Trigger #1759 (GRB 010920?) optical observations
  42. GRB001109, Host Galaxy Astrometry
  43. GRB000926, Host Galaxy Observations
  44. GRB001109, Host Galaxy Spectroscopic Observations
  45. Probable SGR or Short Duration GRB Detected by HETE
  46. GRB000926 Host Galaxy Observations
  47. GRB 010222: HST observations -- host galaxy and late-time decay
  48. BeppoSAX/GRBM detection of GRB 010801
  49. GCN and HETE status
  50. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  51. BeppoSAX/GRBM detection of GRB010728
  52. GRB 010222 - WHT BVRI images
  53. SGR1900+14 burst seen by HETE: BeppoSAX data
  54. GRB 010629 Optical Observations
  55. GRB010629: Optical Observations
  56. SGR1900+14: High Fluence Burst Localized by HETE
  57. GRB010629, optical observations
  58. IPN triangulation of GRB010629
  59. GRB010629: A Burst Localized by HETE
  60. SGR1900+14: Second Burst Localized by HETE
  61. SGR1900+14: A Burst Localized by HETE
  62. Possible burst from SGR1806-20
  63. IPN detection of SGR1900+14
  64. SGR1806-20: A Second, Intense Burst Localized by HETE
  65. GRB 00630: Host Galaxy
  66. SGR1806-20: Localization by HETE
  67. IPN triangulation of GRB010613
  68. IPN triangulation of GRB010612
  69. IPN triangulation of GRB010612
  70. HETE Fully-Automated GCN Notices
  71. GRB000301C: Late-time HST/STIS observation
  72. GRB010518: a faint BeppoSAX detection
  73. GRB000418: HST/STIS Second-epoch Observations
  74. X-ray precursors to the large flare from SGR 1900+14
  75. GRB010214, optical observations
  76. GRB010427, Gamma Ray Observations
  77. SGR 1900+14: No evidence of extended X-ray emission
  78. SGR 1900+14 : RXTE observations
  79. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  80. SGR1900+14 - correction
  81. SGR1900+14
  82. SGR 1900+14: Correction to GCN 1049
  83. GRB 010222 /corrections to VBT data
  84. Millimeter observation of SGR 1900+14
  85. SGR 1900+14: Detection of extended X-ray emission
  86. Chandra Observations of SGR 1900+14
  87. SGR 1900+14, Chandra observations
  88. Chandra Observations of SGR 1900+14
  89. Possible precursor to the SGR1900+14 giant burst
  90. SGR1900+14, I-band observations
  91. IPN Triangulation of the Giant Flare from SGR1900+14
  92. GRB010412, field photometry
  93. Giant flare from SGR1900+14
  94. GRB 010326b Optical Observations
  95. GRB010412: Optical observations
  96. GRB010412: Optical observations
  97. GRB010412: BeppoSAX GRBM and WFC observations
  98. IPN Triangulation of GRB010412
  99. GRB010412: refined positions from BeppoSAX
  100. BeppoSAX GRB: extension of BSAX operations upto April 30, 2002

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