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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. HETE Trigger #1759 (GRB 010920?) optical observations
  2. GRB001109, Host Galaxy Astrometry
  3. GRB000926, Host Galaxy Observations
  4. GRB001109, Host Galaxy Spectroscopic Observations
  5. Probable SGR or Short Duration GRB Detected by HETE
  6. GRB000926 Host Galaxy Observations
  7. GRB 010222: HST observations -- host galaxy and late-time decay
  8. BeppoSAX/GRBM detection of GRB 010801
  9. GCN and HETE status
  10. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  11. BeppoSAX/GRBM detection of GRB010728
  12. GRB 010222 - WHT BVRI images
  13. SGR1900+14 burst seen by HETE: BeppoSAX data
  14. GRB 010629 Optical Observations
  15. GRB010629: Optical Observations
  16. SGR1900+14: High Fluence Burst Localized by HETE
  17. GRB010629, optical observations
  18. IPN triangulation of GRB010629
  19. GRB010629: A Burst Localized by HETE
  20. SGR1900+14: Second Burst Localized by HETE
  21. SGR1900+14: A Burst Localized by HETE
  22. Possible burst from SGR1806-20
  23. IPN detection of SGR1900+14
  24. SGR1806-20: A Second, Intense Burst Localized by HETE
  25. GRB 00630: Host Galaxy
  26. SGR1806-20: Localization by HETE
  27. IPN triangulation of GRB010613
  28. IPN triangulation of GRB010612
  29. IPN triangulation of GRB010612
  30. HETE Fully-Automated GCN Notices
  31. GRB000301C: Late-time HST/STIS observation
  32. GRB010518: a faint BeppoSAX detection
  33. GRB000418: HST/STIS Second-epoch Observations
  34. X-ray precursors to the large flare from SGR 1900+14
  35. GRB010214, optical observations
  36. GRB010427, Gamma Ray Observations
  37. SGR 1900+14: No evidence of extended X-ray emission
  38. SGR 1900+14 : RXTE observations
  39. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  40. SGR1900+14 - correction
  41. SGR1900+14
  42. SGR 1900+14: Correction to GCN 1049
  43. GRB 010222 /corrections to VBT data
  44. Millimeter observation of SGR 1900+14
  45. SGR 1900+14: Detection of extended X-ray emission
  46. Chandra Observations of SGR 1900+14
  47. SGR 1900+14, Chandra observations
  48. Chandra Observations of SGR 1900+14
  49. Possible precursor to the SGR1900+14 giant burst
  50. SGR1900+14, I-band observations
  51. IPN Triangulation of the Giant Flare from SGR1900+14
  52. GRB010412, field photometry
  53. Giant flare from SGR1900+14
  54. GRB 010326b Optical Observations
  55. GRB010412: Optical observations
  56. GRB010412: Optical observations
  57. GRB010412: BeppoSAX GRBM and WFC observations
  58. IPN Triangulation of GRB010412
  59. GRB010412: refined positions from BeppoSAX
  60. BeppoSAX GRB: extension of BSAX operations upto April 30, 2002
  61. BeppoSAX GRB ALERT: GRB010412
  62. GRB Observation Report
  63. GRB010324, revised field photometry
  64. REVISED LOCATION OF GRB010326A
  65. GRB 980326: Late-time HST/STIS observations
  66. GRB010324, field photometry
  67. GRB010326B, field photometry
  68. GRB010326, field photometry
  69. GRB010220, field photometry
  70. Further Optical Observations of GRB 010324
  71. GRB010222, CXO X-ray observations
  72. GRB 010326A: Further optical observations
  73. GRB010324: BeppoSAX/GRBM data
  74. GRB 010326B: Optical observations
  75. GRB010324, optical observations
  76. GRB010326B: Localization by HETE (2nd GRB for this date)
  77. GRB 010326: Optical observations
  78. GRB 010326 optical observations
  79. GRB010326: Refined Localization by HETE
  80. GRB010326: Localization by HETE
  81. Duration, ECT, peak flux and fluence of GRB010324
  82. Optical Observations of GRB 010324
  83. IPN TRIANGULATION OF GRB010324
  84. GRB990705, VLT-FORS1 observations of the host galaxy
  85. GRB010222, late-time optical observation
  86. Support extension to the BeppoSAX mission
  87. GRB 010222 - HEGRA GeV/TeV Observations
  88. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  89. GRB010222: Chandra X-ray Observatory Observation
  90. GRB010222: Sub-millimeter vanishing act
  91. GRB010222 - Optical observation
  92. GRB 010222, Optical Observations
  93. GRB010220 optical obsercations
  94. GRB010222 - Optical observation
  95. GRB 010222: High-Resolution Keck Spectroscopy
  96. GRB010222: Optical observation and decay
  97. GRB 010214, I-band data
  98. Sub-millimeter Excess/GRB 010222
  99. GRB 010222
  100. GRB 010222 HST/Chandra TOO

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