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

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