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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. XRF011030: J and K band observations
  2. GRB011030, optical observation
  3. XRF011030: Chandra Observations
  4. GRB 011030: K-band observations
  5. GRB011030: Z-band observations
  6. GRB 011030 R band observations
  7. GRB 011030 I-band Observation
  8. The X-ray Flash 011030 ('GRB 011030')
  9. Non-triggered burst 011030 ("GRB 011030")
  10. The Radio Afterglow from the X-ray Rich GRB 011030
  11. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  12. GRB 970828: HST Observations of the Host Galaxy
  13. GRB 000131: HST Detection of the Host Galaxy
  14. GRB 970828: HST Observations of the Host Galaxy
  15. GRB010921, optical observation
  16. GRB 011019 optical observation
  17. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  18. GRB011019: Subaru Optical Observations
  19. GRB 011030 I-band Observations
  20. GRB 011030 K-band Observations
  21. GRB010921, optical observations
  22. GRB 011030, WSRT radio observations
  23. GRB011030 - further refinement WFC position
  24. GRB 011030, Radio observations
  25. GRB011030: radio search
  26. GRB 011030, R-band observations
  27. X-ray rich GRB011030: BeppoSAX refined positions
  28. BeppoSAX ALERT: Possible X-ray rich GRB011030
  29. GRB 010921: Possible supernova component
  30. GRB011019: NEAT Optical Observations
  31. GRB011019: ROTSE-III optical observations
  32. GRB010921, optical observation at early time
  33. GRB 010921, I-band observations
  34. GRB011019: Optical observations
  35. GRB011019, optical observations -- correction
  36. GRB011019, optical observations
  37. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  38. GRB010921: Spectroscopy of the Host Galaxy
  39. GRB 010921: The afterglow of HETE #1761
  40. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  41. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  42. GRB010923 as seen by BeppoSAX GRBM
  43. GRB010928(=H1770): Localization of a Long GRB by HETE
  44. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  45. GRB010921, negative optical observations
  46. GRB010921 field photometry
  47. GRB010921 Optical Observations
  48. GRB 010921 DPOSS Images Available
  49. IPN triangulation of GRB010921 (=H1761)
  50. H1761: A Bright GRB Detected by HETE
  51. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  52. HETE Trigger #1760 (GRB 010920B?): a new optical source
  53. HETE Trigger #1759 (GRB 010920?) optical observations
  54. GRB001109, Host Galaxy Astrometry
  55. GRB000926, Host Galaxy Observations
  56. GRB001109, Host Galaxy Spectroscopic Observations
  57. Probable SGR or Short Duration GRB Detected by HETE
  58. GRB000926 Host Galaxy Observations
  59. GRB 010222: HST observations -- host galaxy and late-time decay
  60. BeppoSAX/GRBM detection of GRB 010801
  61. GCN and HETE status
  62. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  63. BeppoSAX/GRBM detection of GRB010728
  64. GRB 010222 - WHT BVRI images
  65. SGR1900+14 burst seen by HETE: BeppoSAX data
  66. GRB 010629 Optical Observations
  67. GRB010629: Optical Observations
  68. SGR1900+14: High Fluence Burst Localized by HETE
  69. GRB010629, optical observations
  70. IPN triangulation of GRB010629
  71. GRB010629: A Burst Localized by HETE
  72. SGR1900+14: Second Burst Localized by HETE
  73. SGR1900+14: A Burst Localized by HETE
  74. Possible burst from SGR1806-20
  75. IPN detection of SGR1900+14
  76. SGR1806-20: A Second, Intense Burst Localized by HETE
  77. GRB 00630: Host Galaxy
  78. SGR1806-20: Localization by HETE
  79. IPN triangulation of GRB010613
  80. IPN triangulation of GRB010612
  81. IPN triangulation of GRB010612
  82. HETE Fully-Automated GCN Notices
  83. GRB000301C: Late-time HST/STIS observation
  84. GRB010518: a faint BeppoSAX detection
  85. GRB000418: HST/STIS Second-epoch Observations
  86. X-ray precursors to the large flare from SGR 1900+14
  87. GRB010214, optical observations
  88. GRB010427, Gamma Ray Observations
  89. SGR 1900+14: No evidence of extended X-ray emission
  90. SGR 1900+14 : RXTE observations
  91. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  92. SGR1900+14 - correction
  93. SGR1900+14
  94. SGR 1900+14: Correction to GCN 1049
  95. GRB 010222 /corrections to VBT data
  96. Millimeter observation of SGR 1900+14
  97. SGR 1900+14: Detection of extended X-ray emission
  98. Chandra Observations of SGR 1900+14
  99. SGR 1900+14, Chandra observations
  100. Chandra Observations of SGR 1900+14

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