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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"

26009 results found.

  1. GRB 011121: Detection of Bright IR Counterpart
  2. GRB011121: possible redshift, continued decay
  3. GRB 011030: TNG K-band observation
  4. XRF011030: J and K band observations
  5. XRF011030: Chandra Observations
  6. GRB011030: Z-band observations
  7. GRB 011030 R band observations
  8. GRB 011030 I-band Observation
  9. The X-ray Flash 011030 ('GRB 011030')
  10. Non-triggered burst 011030 ("GRB 011030")
  11. The Radio Afterglow from the X-ray Rich GRB 011030
  12. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  13. GRB 970828: HST Observations of the Host Galaxy
  14. GRB 000131: HST Detection of the Host Galaxy
  15. GRB 970828: HST Observations of the Host Galaxy
  16. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  17. GRB011019: Subaru Optical Observations
  18. GRB 011030 I-band Observations
  19. GRB 011030 K-band Observations
  20. GRB010921, optical observations
  21. GRB011030 - further refinement WFC position
  22. GRB 011030, Radio observations
  23. GRB011030: radio search
  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. GRB010923 as seen by BeppoSAX GRBM
  33. GRB010928(=H1770): Localization of a Long GRB by HETE
  34. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  35. GRB010921, negative optical observations
  36. GRB010921 field photometry
  37. H1761: A Bright GRB Detected by HETE
  38. GRB000926, Host Galaxy Observations
  39. GRB001109, Host Galaxy Spectroscopic Observations
  40. Probable SGR or Short Duration GRB Detected by HETE
  41. GCN and HETE status
  42. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  43. GRB 010222 - WHT BVRI images
  44. SGR1900+14 burst seen by HETE: BeppoSAX data
  45. GRB 010629 Optical Observations
  46. SGR1900+14: High Fluence Burst Localized by HETE
  47. GRB010629, optical observations
  48. GRB010629: A Burst Localized by HETE
  49. SGR1900+14: Second Burst Localized by HETE
  50. SGR1900+14: A Burst Localized by HETE
  51. SGR1806-20: A Second, Intense Burst Localized by HETE
  52. SGR1806-20: Localization by HETE
  53. HETE Fully-Automated GCN Notices
  54. GRB000301C: Late-time HST/STIS observation
  55. GRB010518: a faint BeppoSAX detection
  56. GRB000418: HST/STIS Second-epoch Observations
  57. X-ray precursors to the large flare from SGR 1900+14
  58. GRB010427, Gamma Ray Observations
  59. SGR 1900+14: No evidence of extended X-ray emission
  60. SGR 1900+14 : RXTE observations
  61. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  62. SGR 1900+14: Correction to GCN 1049
  63. GRB 010222 /corrections to VBT data
  64. Millimeter observation of SGR 1900+14
  65. SGR 1900+14: Detection of extended X-ray emission
  66. SGR 1900+14, Chandra observations
  67. SGR1900+14, I-band observations
  68. GRB010412, field photometry
  69. Giant flare from SGR1900+14
  70. GRB 010326b Optical Observations
  71. GRB010412: BeppoSAX GRBM and WFC observations
  72. GRB010324, revised field photometry
  73. REVISED LOCATION OF GRB010326A
  74. GRB 980326: Late-time HST/STIS observations
  75. GRB010324, field photometry
  76. GRB010326B, field photometry
  77. GRB010326, field photometry
  78. GRB010220, field photometry
  79. Further Optical Observations of GRB 010324
  80. GRB010222, CXO X-ray observations
  81. GRB010324, optical observations
  82. GRB010326B: Localization by HETE (2nd GRB for this date)
  83. GRB 010326 optical observations
  84. GRB010326: Refined Localization by HETE
  85. GRB010326: Localization by HETE
  86. Optical Observations of GRB 010324
  87. GRB010222, late-time optical observation
  88. Support extension to the BeppoSAX mission
  89. GRB 010222 - HEGRA GeV/TeV Observations
  90. GRB010222: Chandra X-ray Observatory Observation
  91. GRB010222: Sub-millimeter vanishing act
  92. GRB010222 - Optical observation
  93. GRB 010222, Optical Observations
  94. GRB010222 - Optical observation
  95. GRB 010222: High-Resolution Keck Spectroscopy
  96. GRB 010214, I-band data
  97. GRB 010222
  98. GRB010222 further R-band photometry
  99. GRB010222: R-band data
  100. GRB 010222: Keck Spectroscopy

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