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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"

23410 results found.

  1. GRB 011121
  2. GRB 011121: J-band observations
  3. GRB 011121: NIR observations, host galaxy?
  4. GRB011121: UBRI Observations
  5. GRB 011121: Radio Observations
  6. GRB 011121 J-Band Astrometry
  7. GRB 011121: Detection of Bright IR Counterpart
  8. GRB011121: possible redshift, continued decay
  9. IPN triangulation of GRB011121
  10. GRB 011030: TNG K-band observation
  11. XRF011030: J and K band observations
  12. XRF011030: Chandra Observations
  13. GRB011030: Z-band observations
  14. The X-ray Flash 011030 ('GRB 011030')
  15. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  16. GRB 970828: HST Observations of the Host Galaxy
  17. GRB 000131: HST Detection of the Host Galaxy
  18. GRB 970828: HST Observations of the Host Galaxy
  19. GRB011019: Subaru Optical Observations
  20. GRB011030 - further refinement WFC position
  21. GRB 011030, Radio observations
  22. GRB011030: radio search
  23. X-ray rich GRB011030: BeppoSAX refined positions
  24. GRB 010921: Possible supernova component
  25. GRB010921, optical observation at early time
  26. GRB 010921, I-band observations
  27. GRB011019, optical observations
  28. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  29. GRB 010921: The afterglow of HETE #1761
  30. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  31. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  32. GRB010928(=H1770): Localization of a Long GRB by HETE
  33. GRB010921, negative optical observations
  34. GRB010921 field photometry
  35. GRB010921 Optical Observations
  36. IPN triangulation of GRB010921 (=H1761)
  37. H1761: A Bright GRB Detected by HETE
  38. HETE Trigger #1760 (GRB 010920B?): a new optical source
  39. HETE Trigger #1759 (GRB 010920?) optical observations
  40. GRB000926, Host Galaxy Observations
  41. GRB001109, Host Galaxy Spectroscopic Observations
  42. GCN and HETE status
  43. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  44. GRB 010222 - WHT BVRI images
  45. GRB 010629 Optical Observations
  46. GRB010629: Optical Observations
  47. SGR1900+14: High Fluence Burst Localized by HETE
  48. GRB010629, optical observations
  49. IPN triangulation of GRB010629
  50. GRB010629: A Burst Localized by HETE
  51. SGR1900+14: Second Burst Localized by HETE
  52. SGR1900+14: A Burst Localized by HETE
  53. SGR1806-20: A Second, Intense Burst Localized by HETE
  54. SGR1806-20: Localization by HETE
  55. IPN triangulation of GRB010613
  56. IPN triangulation of GRB010612
  57. HETE Fully-Automated GCN Notices
  58. GRB000301C: Late-time HST/STIS observation
  59. GRB010518: a faint BeppoSAX detection
  60. GRB000418: HST/STIS Second-epoch Observations
  61. X-ray precursors to the large flare from SGR 1900+14
  62. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  63. Millimeter observation of SGR 1900+14
  64. SGR 1900+14: Detection of extended X-ray emission
  65. SGR 1900+14, Chandra observations
  66. SGR1900+14, I-band observations
  67. GRB010412, field photometry
  68. Giant flare from SGR1900+14
  69. GRB 010326b Optical Observations
  70. GRB010412: BeppoSAX GRBM and WFC observations
  71. IPN Triangulation of GRB010412
  72. GRB Observation Report
  73. GRB010324, revised field photometry
  74. REVISED LOCATION OF GRB010326A
  75. GRB 980326: Late-time HST/STIS observations
  76. GRB010324, field photometry
  77. GRB010326B, field photometry
  78. GRB010326, field photometry
  79. GRB010220, field photometry
  80. Further Optical Observations of GRB 010324
  81. GRB010222, CXO X-ray observations
  82. GRB010324, optical observations
  83. GRB010326B: Localization by HETE (2nd GRB for this date)
  84. GRB 010326 optical observations
  85. GRB010326: Refined Localization by HETE
  86. GRB010326: Localization by HETE
  87. Optical Observations of GRB 010324
  88. GRB990705, VLT-FORS1 observations of the host galaxy
  89. GRB010222, late-time optical observation
  90. Support extension to the BeppoSAX mission
  91. GRB 010222, Optical Observations
  92. GRB010220 optical obsercations
  93. GRB 010222: High-Resolution Keck Spectroscopy
  94. GRB 010214, I-band data
  95. GRB 010222
  96. GRB010222 further R-band photometry
  97. GRB 010222: Keck Spectroscopy
  98. GRB010214, field photometry
  99. GRB010222, field photometry
  100. GRB010222 further R-band photometry

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