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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. GRB011121: possible optical counterpart
  2. GRB011121: BeppoSAX-WFC refined positions
  3. IPN triangulation of GRB011121
  4. BEPPOSAX GRB011121
  5. GRB 011030: TNG K-band observation
  6. XRF011030: J and K band observations
  7. GRB011030, optical observation
  8. XRF011030: Chandra Observations
  9. GRB 011030: K-band observations
  10. GRB011030: Z-band observations
  11. GRB 011030 R band observations
  12. GRB 011030 I-band Observation
  13. The X-ray Flash 011030 ('GRB 011030')
  14. Non-triggered burst 011030 ("GRB 011030")
  15. The Radio Afterglow from the X-ray Rich GRB 011030
  16. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  17. GRB 970828: HST Observations of the Host Galaxy
  18. GRB 000131: HST Detection of the Host Galaxy
  19. GRB 970828: HST Observations of the Host Galaxy
  20. GRB010921, optical observation
  21. GRB 011019 optical observation
  22. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  23. GRB011019: Subaru Optical Observations
  24. GRB 011030 I-band Observations
  25. GRB 011030 K-band Observations
  26. GRB010921, optical observations
  27. GRB 011030, WSRT radio observations
  28. GRB011030 - further refinement WFC position
  29. GRB 011030, Radio observations
  30. GRB011030: radio search
  31. GRB 011030, R-band observations
  32. X-ray rich GRB011030: BeppoSAX refined positions
  33. BeppoSAX ALERT: Possible X-ray rich GRB011030
  34. GRB 010921: Possible supernova component
  35. GRB011019: NEAT Optical Observations
  36. GRB011019: ROTSE-III optical observations
  37. GRB010921, optical observation at early time
  38. GRB 010921, I-band observations
  39. GRB011019: Optical observations
  40. GRB011019, optical observations -- correction
  41. GRB011019, optical observations
  42. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  43. GRB010921: Spectroscopy of the Host Galaxy
  44. GRB 010921: The afterglow of HETE #1761
  45. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  46. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  47. GRB010923 as seen by BeppoSAX GRBM
  48. GRB010928(=H1770): Localization of a Long GRB by HETE
  49. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  50. GRB010921, negative optical observations
  51. GRB010921 field photometry
  52. GRB010921 Optical Observations
  53. GRB 010921 DPOSS Images Available
  54. IPN triangulation of GRB010921 (=H1761)
  55. H1761: A Bright GRB Detected by HETE
  56. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  57. HETE Trigger #1760 (GRB 010920B?): a new optical source
  58. HETE Trigger #1759 (GRB 010920?) optical observations
  59. GRB001109, Host Galaxy Astrometry
  60. GRB000926, Host Galaxy Observations
  61. GRB001109, Host Galaxy Spectroscopic Observations
  62. Probable SGR or Short Duration GRB Detected by HETE
  63. GRB000926 Host Galaxy Observations
  64. GRB 010222: HST observations -- host galaxy and late-time decay
  65. BeppoSAX/GRBM detection of GRB 010801
  66. GCN and HETE status
  67. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  68. BeppoSAX/GRBM detection of GRB010728
  69. GRB 010222 - WHT BVRI images
  70. SGR1900+14 burst seen by HETE: BeppoSAX data
  71. GRB 010629 Optical Observations
  72. GRB010629: Optical Observations
  73. SGR1900+14: High Fluence Burst Localized by HETE
  74. GRB010629, optical observations
  75. IPN triangulation of GRB010629
  76. GRB010629: A Burst Localized by HETE
  77. SGR1900+14: Second Burst Localized by HETE
  78. SGR1900+14: A Burst Localized by HETE
  79. Possible burst from SGR1806-20
  80. IPN detection of SGR1900+14
  81. SGR1806-20: A Second, Intense Burst Localized by HETE
  82. GRB 00630: Host Galaxy
  83. SGR1806-20: Localization by HETE
  84. IPN triangulation of GRB010613
  85. IPN triangulation of GRB010612
  86. IPN triangulation of GRB010612
  87. HETE Fully-Automated GCN Notices
  88. GRB000301C: Late-time HST/STIS observation
  89. GRB010518: a faint BeppoSAX detection
  90. GRB000418: HST/STIS Second-epoch Observations
  91. X-ray precursors to the large flare from SGR 1900+14
  92. GRB010214, optical observations
  93. GRB010427, Gamma Ray Observations
  94. SGR 1900+14: No evidence of extended X-ray emission
  95. SGR 1900+14 : RXTE observations
  96. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  97. SGR1900+14 - correction
  98. SGR1900+14
  99. SGR 1900+14: Correction to GCN 1049
  100. GRB 010222 /corrections to VBT data

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