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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 011030 K-band Observations
  2. GRB010921, optical observations
  3. GRB 011030, WSRT radio observations
  4. GRB011030 - further refinement WFC position
  5. GRB 011030, Radio observations
  6. GRB011030: radio search
  7. GRB 011030, R-band observations
  8. X-ray rich GRB011030: BeppoSAX refined positions
  9. BeppoSAX ALERT: Possible X-ray rich GRB011030
  10. GRB 010921: Possible supernova component
  11. GRB011019: NEAT Optical Observations
  12. GRB011019: ROTSE-III optical observations
  13. GRB010921, optical observation at early time
  14. GRB 010921, I-band observations
  15. GRB011019: Optical observations
  16. GRB011019, optical observations -- correction
  17. GRB011019, optical observations
  18. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  19. GRB010921: Spectroscopy of the Host Galaxy
  20. GRB 010921: The afterglow of HETE #1761
  21. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  22. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  23. GRB010923 as seen by BeppoSAX GRBM
  24. GRB010928(=H1770): Localization of a Long GRB by HETE
  25. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  26. GRB010921, negative optical observations
  27. GRB010921 field photometry
  28. GRB010921 Optical Observations
  29. GRB 010921 DPOSS Images Available
  30. IPN triangulation of GRB010921 (=H1761)
  31. H1761: A Bright GRB Detected by HETE
  32. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  33. HETE Trigger #1760 (GRB 010920B?): a new optical source
  34. HETE Trigger #1759 (GRB 010920?) optical observations
  35. GRB001109, Host Galaxy Astrometry
  36. GRB000926, Host Galaxy Observations
  37. GRB001109, Host Galaxy Spectroscopic Observations
  38. Probable SGR or Short Duration GRB Detected by HETE
  39. GRB000926 Host Galaxy Observations
  40. GRB 010222: HST observations -- host galaxy and late-time decay
  41. BeppoSAX/GRBM detection of GRB 010801
  42. GCN and HETE status
  43. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  44. BeppoSAX/GRBM detection of GRB010728
  45. GRB 010222 - WHT BVRI images
  46. SGR1900+14 burst seen by HETE: BeppoSAX data
  47. GRB 010629 Optical Observations
  48. GRB010629: Optical Observations
  49. SGR1900+14: High Fluence Burst Localized by HETE
  50. GRB010629, optical observations
  51. IPN triangulation of GRB010629
  52. GRB010629: A Burst Localized by HETE
  53. SGR1900+14: Second Burst Localized by HETE
  54. SGR1900+14: A Burst Localized by HETE
  55. Possible burst from SGR1806-20
  56. IPN detection of SGR1900+14
  57. SGR1806-20: A Second, Intense Burst Localized by HETE
  58. GRB 00630: Host Galaxy
  59. SGR1806-20: Localization by HETE
  60. IPN triangulation of GRB010613
  61. IPN triangulation of GRB010612
  62. IPN triangulation of GRB010612
  63. HETE Fully-Automated GCN Notices
  64. GRB000301C: Late-time HST/STIS observation
  65. GRB010518: a faint BeppoSAX detection
  66. GRB000418: HST/STIS Second-epoch Observations
  67. X-ray precursors to the large flare from SGR 1900+14
  68. GRB010214, optical observations
  69. GRB010427, Gamma Ray Observations
  70. SGR 1900+14: No evidence of extended X-ray emission
  71. SGR 1900+14 : RXTE observations
  72. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  73. SGR1900+14 - correction
  74. SGR1900+14
  75. SGR 1900+14: Correction to GCN 1049
  76. GRB 010222 /corrections to VBT data
  77. Millimeter observation of SGR 1900+14
  78. SGR 1900+14: Detection of extended X-ray emission
  79. Chandra Observations of SGR 1900+14
  80. SGR 1900+14, Chandra observations
  81. Chandra Observations of SGR 1900+14
  82. Possible precursor to the SGR1900+14 giant burst
  83. SGR1900+14, I-band observations
  84. IPN Triangulation of the Giant Flare from SGR1900+14
  85. GRB010412, field photometry
  86. Giant flare from SGR1900+14
  87. GRB 010326b Optical Observations
  88. GRB010412: Optical observations
  89. GRB010412: Optical observations
  90. GRB010412: BeppoSAX GRBM and WFC observations
  91. IPN Triangulation of GRB010412
  92. GRB010412: refined positions from BeppoSAX
  93. BeppoSAX GRB: extension of BSAX operations upto April 30, 2002
  94. BeppoSAX GRB ALERT: GRB010412
  95. GRB Observation Report
  96. GRB010324, revised field photometry
  97. REVISED LOCATION OF GRB010326A
  98. GRB 980326: Late-time HST/STIS observations
  99. GRB010324, field photometry
  100. GRB010326B, field photometry

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