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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"

28068 results found.

  1. GRB060403: optical observations
  2. GRB 060403 Optical observations
  3. GRB 060403: MITSuME optical observation
  4. GRB060403: Optical Limit
  5. GRB060403: XRT refined analysis
  6. GRB 060403: Swift/UVOT upper limits
  7. SGR 1900+14: BAT observations
  8. GRB060403: Swift XRT refined position
  9. GRB 060403: Swift detection of a burst
  10. Swift XRT observations of the HETE transient H4043
  11. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  12. SGR 1900+14: Swift-BAT detection of a bright outburst
  13. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  14. GRB 060323 : WIDGET simultaneous optical observations
  15. GRB 060322: Confirmation of Swift XRT afterglow
  16. GRB 060211A: optical observation
  17. GRB060323: optical limit
  18. GRB060211B: optical observation
  19. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  20. SGR 1900+14: Swift detection of renewed activity
  21. GRB060323: NOT optical observations
  22. GRB 060322: IAC80 optical observations
  23. GRB 060322: Swift XRT afterglow candidate
  24. GRB060323: P60 Observations
  25. GRB 060323: Swift/UVOT Observations
  26. GRB 060323: optical afterglow confirmed
  27. GRB060323: NOT observations
  28. GRB 060323: Optical Observations
  29. GRB 060323: Tautenburg OT candidate retraction
  30. GRB 060323: optical observations at TNG
  31. GRB 060323: Swift XRT refined analysis
  32. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  33. GRB 060323: Swift/XRT position
  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. 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. GRB060319: MASTER limit
  43. GRB 060319 optical observations at TNG
  44. GRB060319 : Liverpool Telescope optical limit
  45. GRB060319: Swift/XRT position
  46. GRB 060319: Swift detection of a burst
  47. GRB060313: Radio Observations
  48. GRB 060313: early afterglow NIR upper limits with REM
  49. GRB 060313: PROMPT Observations
  50. GRB 060313: Swift/UVOT Observations
  51. GRB 060313: Swift-XRT team refined analysis
  52. GRB060313: optical observations of the afterglow candidate
  53. GRB 060313, SMARTS optical counterpart?
  54. GRB 060313: Possible optical counterpart
  55. GRB 060313: Swift XRT position
  56. GRB 060313, SMARTS optical/IR observations
  57. GRB 060313: Swift-BAT detection of a bright short hard burst
  58. GRB060312: Swift UVOT observation
  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. GRB 060306: SOAR Ks Observations
  64. GRB060219: Liverpool Telescope observations
  65. GRB 060306: MAGNUM observations
  66. GRB060218: analysis of the XMM-Newton observation
  67. Swift/UVOT observations of GRB060306
  68. GRB 060306: Swift-XRT team refined analysis
  69. GRB 060306: Swift detection of a bright burst
  70. GRB060218: Ep,i - Eiso correlation
  71. GRB060223b: optical limit
  72. GRB060218/SN 2006aj: optical observation in V
  73. GRB060218/SN 2006aj: optical observation
  74. GRB 060121: HST observations
  75. GRB 060218 : GMRT observation [Correction and Improvement]
  76. GRB 060223b: Swift/UVOT Upper Limits
  77. GRB 060218/SN 2006aj: K-380 optical observations
  78. GRB 060223B: Swift XRT possible afterglow
  79. GRB 060218/SN 2006aj: ABT observations
  80. GRB 060218 : Radio upper limits from GMRT
  81. GRB 060204B: GETS early limit
  82. GRB 060218: Refined analysis of the radio afterglow
  83. GRB 060223A:Xinglong optical limits
  84. GRB 060223a: Swift/UVOT refined analysis
  85. GRB 060223: Swift XRT Team preliminary analysis
  86. GRB 060223B: Swift detection of a bright burst
  87. GRB 060223: Swift-BAT refined analysis
  88. Correction to GCN 4816 on GRB060218
  89. GRB060218: Optical brightening in V and R
  90. GRB 060223: Keck redshift
  91. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  92. GRB 060223: Swift detection of a burst
  93. Spectral properties of GRB060218/SN2006aj
  94. GRB 060218: Decline in r-band flux
  95. GRB 060218: spectroscopic observations
  96. GRB 060218: Likely an underluminous GRB
  97. GRB060218: Optical Spectroscopy of GRB-SN
  98. GRB 060219: SDSS galaxy inside XRT error circle
  99. GRB060218: UV Detection and Light Curves
  100. GRB 060219: Swift/UVOT Upper Limits

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