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

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