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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. GRB060323: NOT optical observations
  2. GRB 060322: IAC80 optical observations
  3. GRB 060322: Swift XRT afterglow candidate
  4. GRB060323: P60 Observations
  5. GRB 060323: Swift/UVOT Observations
  6. GRB 060323: optical afterglow confirmed
  7. GRB060323: NOT observations
  8. GRB 060323: Optical Observations
  9. GRB 060323: Tautenburg OT candidate retraction
  10. GRB 060323: Refined analysis of the Swift-BAT burst
  11. GRB 060323: optical observations at TNG
  12. GRB 060323: Swift XRT refined analysis
  13. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  14. GRB 060323: Swift/XRT position
  15. GRB 060322: Refined analysis of the Swift-BAT burst
  16. GRB060323, optical observation
  17. GRB060323 - SDSS Pre-Burst Observations
  18. GRB 060323: Swift detection of a burst with a possible optical afterglow
  19. GRB 060322: Swift-BAT detection of a 200-sec burst
  20. GRB060219: optical observation
  21. GRB060206: optical observation
  22. GRB060218/SN2006aj: optical observations
  23. GRB 060218/SN 2006aj, LNA optical observation
  24. GRB060218: Refined photometric calibration of comparison stars
  25. GRB 060319: WHT K-band candidate afterglow
  26. GRB 060319: IAC-80 optical observations
  27. GRB060319: Swift XRT refined analysis
  28. GRB060319: Swift/UVOT upper limits
  29. GRB 060319: Re-analysis of TNG data
  30. GRB060319: MASTER limit
  31. GRB 060319: Swift-BAT refined analysis
  32. GRB 060319 optical observations at TNG
  33. GRB060319 : Liverpool Telescope optical limit
  34. GRB060319: MASTER optical observation
  35. GRB060319 - SDSS Pre-burst Observations
  36. GRB060319: Swift/XRT position
  37. GRB 060319: Swift detection of a burst
  38. GRB060313: Radio Observations
  39. GRB 060313: early afterglow NIR upper limits with REM
  40. IBAS Alert n. 3221: not a GRB
  41. Konus-Wind observation of GRB 060313
  42. GRB060313: SSO 40inch Observations
  43. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  44. GRB 060313: PROMPT Observations
  45. GRB 060313: Swift/UVOT Observations
  46. GRB060313:Gemini South Observations
  47. GRB 060313: Swift-XRT team refined analysis
  48. GRB060313: optical observations of the afterglow candidate
  49. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  50. GRB 060313, SMARTS optical counterpart?
  51. GRB 060313: Possible optical counterpart
  52. GRB 060313: Swift XRT position
  53. GRB 060313, SMARTS optical/IR observations
  54. GRB060313: optical and near infrared observations with REM
  55. GRB 060313: Swift-BAT detection of a bright short hard burst
  56. GRB060218: SARA Observations of SN2006aj
  57. GRB060312: Swift UVOT observation
  58. GRB 060312: Refined analysis of the Swift-BAT burst
  59. GRB 060218/SN 2006aj, high resolution spectra
  60. GRB 060312: Swift XRT team refined analysis
  61. GRB060306: APO Ks-band Imaging Observations
  62. GRB 060312: ROTSE-III Optical Limits
  63. GRB 060312: Swift detection of a burst
  64. IBAS Alert n. 3218 : not a real GRB
  65. GRB 060306: SOAR Ks Observations
  66. Bright short hard GRB 060303: IPN localization and Konus spectrum
  67. GRB060219: Liverpool Telescope observations
  68. GRB 060306: MAGNUM observations
  69. GRB060218: analysis of the XMM-Newton observation
  70. Swift/UVOT observations of GRB060306
  71. GRB 060306: Swift-BAT refined analysis
  72. GRB 060306: Swift-XRT team refined analysis
  73. GRB 060306: PROMPT Observations
  74. GRB 060306: Swift detection of a bright burst
  75. GRB 060218: RTT150 optical observations
  76. GRB060218: Ep,i - Eiso correlation
  77. GRB060218: R-band CCD photmetry
  78. GRB060223b: optical limit
  79. GRB060218/SN 2006aj: optical observation in V
  80. GRB060218/SN 2006aj: optical observation
  81. GRB 060121: HST observations
  82. GRB 060218 : GMRT observation [Correction and Improvement]
  83. GRB 060223b: Swift/UVOT Upper Limits
  84. GRB 060218/SN 2006aj: K-380 optical observations
  85. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  86. GRB200618: optical polarimetry and photometry
  87. GRB 060223B: Swift XRT possible afterglow
  88. GRB 060218/SN 2006aj: ABT observations
  89. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  90. GRB 060218 : Radio upper limits from GMRT
  91. GRB 060218/SN 2006aj: WIRO optical observations
  92. GRB 060218/SN 2006aj: RBO optical observations
  93. GRB 060204B: GETS early limit
  94. GRB 060218: Refined analysis of the radio afterglow
  95. GRB 060223A:Xinglong optical limits
  96. GRB 060223B: ART optical limits
  97. GRB 060223B: Swift-BAT refined analysis
  98. GRB 060223a: Swift/UVOT refined analysis
  99. GRB 060223: Swift XRT Team preliminary analysis
  100. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux

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