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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"

27392 results found.

  1. GRB 011030 I-band Observations
  2. GRB 011030 K-band Observations
  3. GRB010921, optical observations
  4. GRB011030 - further refinement WFC position
  5. GRB 011030, Radio observations
  6. GRB011030: radio search
  7. GRB 010921: Possible supernova component
  8. GRB010921, optical observation at early time
  9. GRB 010921, I-band observations
  10. GRB011019, optical observations
  11. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  12. GRB 010921: The afterglow of HETE #1761
  13. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  14. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  15. GRB010923 as seen by BeppoSAX GRBM
  16. GRB010928(=H1770): Localization of a Long GRB by HETE
  17. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  18. GRB010921, negative optical observations
  19. GRB010921 field photometry
  20. H1761: A Bright GRB Detected by HETE
  21. GRB000926, Host Galaxy Observations
  22. GRB001109, Host Galaxy Spectroscopic Observations
  23. Probable SGR or Short Duration GRB Detected by HETE
  24. GCN and HETE status
  25. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  26. GRB 010222 - WHT BVRI images
  27. SGR1900+14 burst seen by HETE: BeppoSAX data
  28. GRB 010629 Optical Observations
  29. SGR1900+14: High Fluence Burst Localized by HETE
  30. GRB010629, optical observations
  31. GRB010629: A Burst Localized by HETE
  32. SGR1900+14: Second Burst Localized by HETE
  33. SGR1900+14: A Burst Localized by HETE
  34. SGR1806-20: A Second, Intense Burst Localized by HETE
  35. SGR1806-20: Localization by HETE
  36. HETE Fully-Automated GCN Notices
  37. GRB000301C: Late-time HST/STIS observation
  38. GRB010518: a faint BeppoSAX detection
  39. GRB000418: HST/STIS Second-epoch Observations
  40. X-ray precursors to the large flare from SGR 1900+14
  41. GRB010427, Gamma Ray Observations
  42. SGR 1900+14: No evidence of extended X-ray emission
  43. SGR 1900+14 : RXTE observations
  44. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  45. SGR 1900+14: Correction to GCN 1049
  46. GRB 010222 /corrections to VBT data
  47. Millimeter observation of SGR 1900+14
  48. SGR 1900+14: Detection of extended X-ray emission
  49. SGR 1900+14, Chandra observations
  50. SGR1900+14, I-band observations
  51. GRB010412, field photometry
  52. Giant flare from SGR1900+14
  53. GRB 010326b Optical Observations
  54. GRB010412: BeppoSAX GRBM and WFC observations
  55. GRB010324, revised field photometry
  56. REVISED LOCATION OF GRB010326A
  57. GRB 980326: Late-time HST/STIS observations
  58. GRB010324, field photometry
  59. GRB010326B, field photometry
  60. GRB010326, field photometry
  61. GRB010220, field photometry
  62. Further Optical Observations of GRB 010324
  63. GRB010222, CXO X-ray observations
  64. GRB010324, optical observations
  65. GRB010326B: Localization by HETE (2nd GRB for this date)
  66. GRB 010326 optical observations
  67. GRB010326: Refined Localization by HETE
  68. GRB010326: Localization by HETE
  69. Optical Observations of GRB 010324
  70. GRB010222, late-time optical observation
  71. Support extension to the BeppoSAX mission
  72. GRB 010222 - HEGRA GeV/TeV Observations
  73. GRB010222: Chandra X-ray Observatory Observation
  74. GRB010222: Sub-millimeter vanishing act
  75. GRB010222 - Optical observation
  76. GRB 010222, Optical Observations
  77. GRB010222 - Optical observation
  78. GRB 010222: High-Resolution Keck Spectroscopy
  79. GRB 010214, I-band data
  80. GRB 010222
  81. GRB010222 further R-band photometry
  82. GRB010222: R-band data
  83. GRB 010222: Keck Spectroscopy
  84. GRB010214, field photometry
  85. GRB010222, field photometry
  86. GRB010222 further R-band photometry
  87. GRB010222, possible increase of optical decay slope
  88. GRB 010222 Kyoto optical observation
  89. GRB010222 R-BAND OBSERVATION
  90. GRB010214 follow-up from Hanle
  91. GRB 010222: Near-IR Observations
  92. GRB 010222: Optical Observations
  93. GRB010222: Optical decay slope
  94. GRB 010214, Optical Observations
  95. GRB010222, radio observations
  96. GRB010222, optical observations
  97. GRB010222: BeppoSAX/NFI Observations
  98. GRB010214B,Gamma Ray Observations
  99. GRB 010220, simultaneous optical observations
  100. GRB010220: BeppoSAX WFC and GRBM preliminary data

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