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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. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  2. SGR 1900+14: Swift-BAT detection of a bright outburst
  3. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  4. GRB 060323 : WIDGET simultaneous optical observations
  5. GRB 060323: Early optical observation at Xinglong
  6. GRB060218, optical observations
  7. GRB 060322: Confirmation of Swift XRT afterglow
  8. GRB 060211A: optical observation
  9. GRB060323: optical limit
  10. GRB060211B: optical observation
  11. SGR 1900+14: CORRECTION to GCN 4923
  12. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  13. SGR 1900+14: Swift detection of renewed activity
  14. GRB060323: NOT optical observations
  15. GRB 060322: IAC80 optical observations
  16. GRB 060322: Swift XRT afterglow candidate
  17. GRB060323: P60 Observations
  18. GRB 060323: Swift/UVOT Observations
  19. GRB 060323: optical afterglow confirmed
  20. GRB060323: NOT observations
  21. GRB 060323: Optical Observations
  22. GRB 060323: Tautenburg OT candidate retraction
  23. GRB 060323: Refined analysis of the Swift-BAT burst
  24. GRB 060323: optical observations at TNG
  25. GRB 060323: Swift XRT refined analysis
  26. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  27. GRB 060323: Swift/XRT position
  28. GRB 060322: Refined analysis of the Swift-BAT burst
  29. GRB060323, optical observation
  30. GRB060323 - SDSS Pre-Burst Observations
  31. GRB 060323: Swift detection of a burst with a possible optical afterglow
  32. GRB 060322: Swift-BAT detection of a 200-sec burst
  33. GRB060219: optical observation
  34. GRB060206: optical observation
  35. GRB060218/SN2006aj: optical observations
  36. GRB 060218/SN 2006aj, LNA optical observation
  37. GRB060218: Refined photometric calibration of comparison stars
  38. GRB 060319: WHT K-band candidate afterglow
  39. GRB 060319: IAC-80 optical observations
  40. GRB060319: Swift XRT refined analysis
  41. GRB060319: Swift/UVOT upper limits
  42. GRB 060319: Re-analysis of TNG data
  43. GRB060319: MASTER limit
  44. GRB 060319: Swift-BAT refined analysis
  45. GRB 060319 optical observations at TNG
  46. GRB060319 : Liverpool Telescope optical limit
  47. GRB060319: MASTER optical observation
  48. GRB060319 - SDSS Pre-burst Observations
  49. GRB060319: Swift/XRT position
  50. GRB 060319: Swift detection of a burst
  51. GRB060313: Radio Observations
  52. GRB 060313: early afterglow NIR upper limits with REM
  53. IBAS Alert n. 3221: not a GRB
  54. Konus-Wind observation of GRB 060313
  55. GRB060313: SSO 40inch Observations
  56. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  57. GRB 060313: PROMPT Observations
  58. GRB 060313: Swift/UVOT Observations
  59. GRB060313:Gemini South Observations
  60. GRB 060313: Swift-XRT team refined analysis
  61. GRB060313: optical observations of the afterglow candidate
  62. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  63. GRB 060313, SMARTS optical counterpart?
  64. GRB 060313: Possible optical counterpart
  65. GRB 060313: Swift XRT position
  66. GRB 060313, SMARTS optical/IR observations
  67. GRB060313: optical and near infrared observations with REM
  68. GRB 060313: Swift-BAT detection of a bright short hard burst
  69. GRB060218: SARA Observations of SN2006aj
  70. GRB060312: Swift UVOT observation
  71. GRB 060312: Refined analysis of the Swift-BAT burst
  72. GRB 060218/SN 2006aj, high resolution spectra
  73. GRB 060312: Swift XRT team refined analysis
  74. GRB060306: APO Ks-band Imaging Observations
  75. GRB 060312: ROTSE-III Optical Limits
  76. GRB 060312: Swift detection of a burst
  77. IBAS Alert n. 3218 : not a real GRB
  78. GRB 060306: SOAR Ks Observations
  79. Bright short hard GRB 060303: IPN localization and Konus spectrum
  80. GRB060219: Liverpool Telescope observations
  81. GRB 060306: MAGNUM observations
  82. GRB060218: analysis of the XMM-Newton observation
  83. Swift/UVOT observations of GRB060306
  84. GRB 060306: Swift-BAT refined analysis
  85. GRB 060306: Swift-XRT team refined analysis
  86. GRB 060306: PROMPT Observations
  87. GRB 060306: Swift detection of a bright burst
  88. GRB 060218: RTT150 optical observations
  89. GRB060218: Ep,i - Eiso correlation
  90. GRB060218: R-band CCD photmetry
  91. GRB060223b: optical limit
  92. GRB060218/SN 2006aj: optical observation in V
  93. GRB060218/SN 2006aj: optical observation
  94. GRB 060121: HST observations
  95. GRB 060218 : GMRT observation [Correction and Improvement]
  96. GRB 060223b: Swift/UVOT Upper Limits
  97. GRB 060218/SN 2006aj: K-380 optical observations
  98. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  99. GRB200618: optical polarimetry and photometry
  100. GRB 060223B: Swift XRT possible afterglow

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