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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').
  1. Possible precursor to the SGR1900+14 giant burst
  2. SGR1900+14, I-band observations
  3. IPN Triangulation of the Giant Flare from SGR1900+14
  4. GRB010412, field photometry
  5. Giant flare from SGR1900+14
  6. GRB 010326b Optical Observations
  7. GRB010412: Optical observations
  8. GRB010412: Optical observations
  9. GRB010412: BeppoSAX GRBM and WFC observations
  10. IPN Triangulation of GRB010412
  11. GRB010412: refined positions from BeppoSAX
  12. BeppoSAX GRB: extension of BSAX operations upto April 30, 2002
  13. BeppoSAX GRB ALERT: GRB010412
  14. GRB Observation Report
  15. GRB010324, revised field photometry
  16. REVISED LOCATION OF GRB010326A
  17. GRB 980326: Late-time HST/STIS observations
  18. GRB010324, field photometry
  19. GRB010326B, field photometry
  20. GRB010326, field photometry
  21. GRB010220, field photometry
  22. Further Optical Observations of GRB 010324
  23. GRB010222, CXO X-ray observations
  24. GRB 010326A: Further optical observations
  25. GRB010324: BeppoSAX/GRBM data
  26. GRB 010326B: Optical observations
  27. GRB010324, optical observations
  28. GRB010326B: Localization by HETE (2nd GRB for this date)
  29. GRB 010326: Optical observations
  30. GRB 010326 optical observations
  31. GRB010326: Refined Localization by HETE
  32. GRB010326: Localization by HETE
  33. Duration, ECT, peak flux and fluence of GRB010324
  34. Optical Observations of GRB 010324
  35. IPN TRIANGULATION OF GRB010324
  36. GRB990705, VLT-FORS1 observations of the host galaxy
  37. GRB010222, late-time optical observation
  38. Support extension to the BeppoSAX mission
  39. GRB 010222 - HEGRA GeV/TeV Observations
  40. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  41. GRB010222: Chandra X-ray Observatory Observation
  42. GRB010222: Sub-millimeter vanishing act
  43. GRB010222 - Optical observation
  44. GRB 010222, Optical Observations
  45. GRB010220 optical obsercations
  46. GRB010222 - Optical observation
  47. GRB 010222: High-Resolution Keck Spectroscopy
  48. GRB010222: Optical observation and decay
  49. GRB 010214, I-band data
  50. Sub-millimeter Excess/GRB 010222
  51. GRB 010222
  52. GRB 010222 HST/Chandra TOO
  53. GRB 010222
  54. GRB010222 further R-band photometry
  55. GRB010222: R-band data
  56. GRB010222 Optical observations
  57. GRB 010222: Keck Spectroscopy
  58. GRB010214, field photometry
  59. GRB010222, field photometry
  60. GRB010222 further R-band photometry
  61. GRB010222, possible increase of optical decay slope
  62. GRB 010222 Kyoto optical observation
  63. GRB010222: fading behavior
  64. GRB 010222 BV optical observations
  65. GRB010220, Optical Observations
  66. GRB010222 R-BAND OBSERVATION
  67. GRB 010220: Near-IR Observations
  68. GRB010214 follow-up from Hanle
  69. GRB 010222: Near-IR Observations
  70. GRB 010222: Optical Observations
  71. GRB 010222, Decay Slope Confirmed
  72. GRB010222: Another absorption line system
  73. GRB010222: Optical decay slope
  74. GRB 010214, Optical Observations
  75. GRB010222: Sub-millimeter detection
  76. GRB010222: R-band fading behavior
  77. GRB010222: Optical Observations
  78. GRB010222, radio observations
  79. GRB010222, optical observations
  80. GRB010222: BeppoSAX/NFI Observations
  81. Redshift of the Optical Transient of GRB010222
  82. GRB010214B,Gamma Ray Observations
  83. GRB010222: possible optical counterpart
  84. GRB010222
  85. GRB010222
  86. GRB010222: BeppoSAX refined position
  87. ALERT: GRB010222: the brightest GRB observed by BeppoSAX
  88. GRB010220, Radio and Optical Observations
  89. GRB 010220, simultaneous optical observations
  90. GRB010220: BeppoSAX WFC and GRBM preliminary data
  91. GRB010214, candidate optical afterglow
  92. GRB010214, optical observations
  93. BeppoSAX GRB010220: refined position
  94. BeppoSAX ALERT: GRB010220
  95. GRB010214: BeppoSAX WFC and GRBM preliminary data
  96. GRB 010214: X-Ray afterglow
  97. GRB 010214, Optical Observations
  98. GRB 010214 optical observation
  99. GRB010213, Radio Observations
  100. GRB010213 Optical Observation

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