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

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