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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. GRB 060322: LNA optical limit
  2. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  3. INTEGRAL and XMM ToO observations of SGR1900+14
  4. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  5. SGR 1900+14: Swift-BAT detection of a bright outburst
  6. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  7. GRB 060323 : WIDGET simultaneous optical observations
  8. GRB 060323: Early optical observation at Xinglong
  9. GRB060218, optical observations
  10. GRB 060322: Confirmation of Swift XRT afterglow
  11. GRB 060211A: optical observation
  12. GRB060323: optical limit
  13. GRB060211B: optical observation
  14. SGR 1900+14: CORRECTION to GCN 4923
  15. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  16. SGR 1900+14: Swift detection of renewed activity
  17. GRB060323: NOT optical observations
  18. GRB 060322: IAC80 optical observations
  19. GRB 060322: Swift XRT afterglow candidate
  20. GRB060323: P60 Observations
  21. GRB 060323: Swift/UVOT Observations
  22. GRB 060323: optical afterglow confirmed
  23. GRB060323: NOT observations
  24. GRB 060323: Optical Observations
  25. GRB 060323: Tautenburg OT candidate retraction
  26. GRB 060323: Refined analysis of the Swift-BAT burst
  27. GRB 060323: optical observations at TNG
  28. GRB 060323: Swift XRT refined analysis
  29. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  30. GRB 060323: Swift/XRT position
  31. GRB 060322: Refined analysis of the Swift-BAT burst
  32. GRB060323, optical observation
  33. GRB060323 - SDSS Pre-Burst Observations
  34. GRB 060323: Swift detection of a burst with a possible optical afterglow
  35. GRB 060322: Swift-BAT detection of a 200-sec burst
  36. GRB060219: optical observation
  37. GRB060206: optical observation
  38. GRB060218/SN2006aj: optical observations
  39. GRB 060218/SN 2006aj, LNA optical observation
  40. GRB060218: Refined photometric calibration of comparison stars
  41. GRB 060319: WHT K-band candidate afterglow
  42. GRB 060319: IAC-80 optical observations
  43. GRB060319: Swift XRT refined analysis
  44. GRB060319: Swift/UVOT upper limits
  45. GRB 060319: Re-analysis of TNG data
  46. GRB060319: MASTER limit
  47. GRB 060319: Swift-BAT refined analysis
  48. GRB 060319 optical observations at TNG
  49. GRB060319 : Liverpool Telescope optical limit
  50. GRB060319: MASTER optical observation
  51. GRB060319 - SDSS Pre-burst Observations
  52. GRB060319: Swift/XRT position
  53. GRB 060319: Swift detection of a burst
  54. GRB060313: Radio Observations
  55. GRB 060313: early afterglow NIR upper limits with REM
  56. IBAS Alert n. 3221: not a GRB
  57. Konus-Wind observation of GRB 060313
  58. GRB060313: SSO 40inch Observations
  59. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  60. GRB 060313: PROMPT Observations
  61. GRB 060313: Swift/UVOT Observations
  62. GRB060313:Gemini South Observations
  63. GRB 060313: Swift-XRT team refined analysis
  64. GRB060313: optical observations of the afterglow candidate
  65. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  66. GRB 060313, SMARTS optical counterpart?
  67. GRB 060313: Possible optical counterpart
  68. GRB 060313: Swift XRT position
  69. GRB 060313, SMARTS optical/IR observations
  70. GRB060313: optical and near infrared observations with REM
  71. GRB 060313: Swift-BAT detection of a bright short hard burst
  72. GRB060218: SARA Observations of SN2006aj
  73. GRB060312: Swift UVOT observation
  74. GRB 060312: Refined analysis of the Swift-BAT burst
  75. GRB 060218/SN 2006aj, high resolution spectra
  76. GRB 060312: Swift XRT team refined analysis
  77. GRB060306: APO Ks-band Imaging Observations
  78. GRB 060312: ROTSE-III Optical Limits
  79. GRB 060312: Swift detection of a burst
  80. IBAS Alert n. 3218 : not a real GRB
  81. GRB 060306: SOAR Ks Observations
  82. Bright short hard GRB 060303: IPN localization and Konus spectrum
  83. GRB060219: Liverpool Telescope observations
  84. GRB 060306: MAGNUM observations
  85. GRB060218: analysis of the XMM-Newton observation
  86. Swift/UVOT observations of GRB060306
  87. GRB 060306: Swift-BAT refined analysis
  88. GRB 060306: Swift-XRT team refined analysis
  89. GRB 060306: PROMPT Observations
  90. GRB 060306: Swift detection of a bright burst
  91. GRB 060218: RTT150 optical observations
  92. GRB060218: Ep,i - Eiso correlation
  93. GRB060218: R-band CCD photmetry
  94. GRB060223b: optical limit
  95. GRB060218/SN 2006aj: optical observation in V
  96. GRB060218/SN 2006aj: optical observation
  97. GRB 060121: HST observations
  98. GRB 060218 : GMRT observation [Correction and Improvement]
  99. GRB 060223b: Swift/UVOT Upper Limits
  100. GRB 060218/SN 2006aj: K-380 optical observations

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