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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, optical observation
  2. GRB060323 - SDSS Pre-Burst Observations
  3. GRB 060323: Swift detection of a burst with a possible optical afterglow
  4. GRB 060322: Swift-BAT detection of a 200-sec burst
  5. GRB060219: optical observation
  6. GRB060206: optical observation
  7. GRB060218/SN2006aj: optical observations
  8. GRB 060218/SN 2006aj, LNA optical observation
  9. GRB060218: Refined photometric calibration of comparison stars
  10. GRB 060319: WHT K-band candidate afterglow
  11. GRB 060319: IAC-80 optical observations
  12. GRB060319: Swift XRT refined analysis
  13. GRB060319: Swift/UVOT upper limits
  14. GRB 060319: Re-analysis of TNG data
  15. GRB060319: MASTER limit
  16. GRB 060319: Swift-BAT refined analysis
  17. GRB 060319 optical observations at TNG
  18. GRB060319 : Liverpool Telescope optical limit
  19. GRB060319: MASTER optical observation
  20. GRB060319 - SDSS Pre-burst Observations
  21. GRB060319: Swift/XRT position
  22. GRB 060319: Swift detection of a burst
  23. GRB060313: Radio Observations
  24. GRB 060313: early afterglow NIR upper limits with REM
  25. IBAS Alert n. 3221: not a GRB
  26. Konus-Wind observation of GRB 060313
  27. GRB060313: SSO 40inch Observations
  28. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  29. GRB 060313: PROMPT Observations
  30. GRB 060313: Swift/UVOT Observations
  31. GRB060313:Gemini South Observations
  32. GRB 060313: Swift-XRT team refined analysis
  33. GRB060313: optical observations of the afterglow candidate
  34. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  35. GRB 060313, SMARTS optical counterpart?
  36. GRB 060313: Possible optical counterpart
  37. GRB 060313: Swift XRT position
  38. GRB 060313, SMARTS optical/IR observations
  39. GRB060313: optical and near infrared observations with REM
  40. GRB 060313: Swift-BAT detection of a bright short hard burst
  41. GRB060218: SARA Observations of SN2006aj
  42. GRB060312: Swift UVOT observation
  43. GRB 060312: Refined analysis of the Swift-BAT burst
  44. GRB 060218/SN 2006aj, high resolution spectra
  45. GRB 060312: Swift XRT team refined analysis
  46. GRB060306: APO Ks-band Imaging Observations
  47. GRB 060312: ROTSE-III Optical Limits
  48. GRB 060312: Swift detection of a burst
  49. IBAS Alert n. 3218 : not a real GRB
  50. GRB 060306: SOAR Ks Observations
  51. Bright short hard GRB 060303: IPN localization and Konus spectrum
  52. GRB060219: Liverpool Telescope observations
  53. GRB 060306: MAGNUM observations
  54. GRB060218: analysis of the XMM-Newton observation
  55. Swift/UVOT observations of GRB060306
  56. GRB 060306: Swift-BAT refined analysis
  57. GRB 060306: Swift-XRT team refined analysis
  58. GRB 060306: PROMPT Observations
  59. GRB 060306: Swift detection of a bright burst
  60. GRB 060218: RTT150 optical observations
  61. GRB060218: Ep,i - Eiso correlation
  62. GRB060218: R-band CCD photmetry
  63. GRB060223b: optical limit
  64. GRB060218/SN 2006aj: optical observation in V
  65. GRB060218/SN 2006aj: optical observation
  66. GRB 060121: HST observations
  67. GRB 060218 : GMRT observation [Correction and Improvement]
  68. GRB 060223b: Swift/UVOT Upper Limits
  69. GRB 060218/SN 2006aj: K-380 optical observations
  70. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  71. GRB200618: optical polarimetry and photometry
  72. GRB 060223B: Swift XRT possible afterglow
  73. GRB 060218/SN 2006aj: ABT observations
  74. GRB 060218/SN 2006aj: REM optical and near-infrared observations
  75. GRB 060218 : Radio upper limits from GMRT
  76. GRB 060218/SN 2006aj: WIRO optical observations
  77. GRB 060218/SN 2006aj: RBO optical observations
  78. GRB 060204B: GETS early limit
  79. GRB 060218: Refined analysis of the radio afterglow
  80. GRB 060223A:Xinglong optical limits
  81. GRB 060223B: ART optical limits
  82. GRB 060223B: Swift-BAT refined analysis
  83. GRB 060223a: Swift/UVOT refined analysis
  84. GRB 060223: Swift XRT Team preliminary analysis
  85. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  86. GRB 060223B: Swift detection of a bright burst
  87. GRB 060223: Swift-BAT refined analysis
  88. GRB 060218: rebrightening
  89. Correction to GCN 4816 on GRB060218
  90. GRB 060218/SN 2006aj: optical observations
  91. GRB060218: Optical brightening in V and R
  92. GRB 060223: Keck redshift
  93. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  94. GRB 060223: Swift detection of a burst
  95. Spectral properties of GRB060218/SN2006aj
  96. GRB 060219: Swift-BAT refined analysis
  97. GRB 060218: rebrightening
  98. GRB 060218: emergence of the underlying SN spectrum
  99. GRB 060218: Decline in r-band flux
  100. GRB 060218: spectroscopic observations

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