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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"

28069 results found.

  1. GRB 060413: Swift detection of a burst
  2. GRB060403: optical observations
  3. GRB 060403 Optical observations
  4. GRB 060403: MITSuME optical observation
  5. GRB060403: Optical Limit
  6. GRB060403: XRT refined analysis
  7. GRB 060403: Swift/UVOT upper limits
  8. SGR 1900+14: BAT observations
  9. GRB060403: Swift XRT refined position
  10. GRB 060403: Swift detection of a burst
  11. Swift XRT observations of the HETE transient H4043
  12. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  13. SGR 1900+14: Swift-BAT detection of a bright outburst
  14. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  15. GRB 060323 : WIDGET simultaneous optical observations
  16. GRB 060322: Confirmation of Swift XRT afterglow
  17. GRB 060211A: optical observation
  18. GRB060323: optical limit
  19. GRB060211B: optical observation
  20. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  21. SGR 1900+14: Swift detection of renewed activity
  22. GRB060323: NOT optical observations
  23. GRB 060322: IAC80 optical observations
  24. GRB 060322: Swift XRT afterglow candidate
  25. GRB060323: P60 Observations
  26. GRB 060323: Swift/UVOT Observations
  27. GRB 060323: optical afterglow confirmed
  28. GRB060323: NOT observations
  29. GRB 060323: Optical Observations
  30. GRB 060323: Tautenburg OT candidate retraction
  31. GRB 060323: optical observations at TNG
  32. GRB 060323: Swift XRT refined analysis
  33. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  34. GRB 060323: Swift/XRT position
  35. GRB 060323: Swift detection of a burst with a possible optical afterglow
  36. GRB 060322: Swift-BAT detection of a 200-sec burst
  37. GRB060219: optical observation
  38. GRB060206: optical observation
  39. GRB 060319: WHT K-band candidate afterglow
  40. GRB 060319: IAC-80 optical observations
  41. GRB060319: Swift XRT refined analysis
  42. GRB060319: Swift/UVOT upper limits
  43. GRB060319: MASTER limit
  44. GRB 060319 optical observations at TNG
  45. GRB060319 : Liverpool Telescope optical limit
  46. GRB060319: Swift/XRT position
  47. GRB 060319: Swift detection of a burst
  48. GRB060313: Radio Observations
  49. GRB 060313: early afterglow NIR upper limits with REM
  50. GRB 060313: PROMPT Observations
  51. GRB 060313: Swift/UVOT Observations
  52. GRB 060313: Swift-XRT team refined analysis
  53. GRB060313: optical observations of the afterglow candidate
  54. GRB 060313, SMARTS optical counterpart?
  55. GRB 060313: Possible optical counterpart
  56. GRB 060313: Swift XRT position
  57. GRB 060313, SMARTS optical/IR observations
  58. GRB 060313: Swift-BAT detection of a bright short hard burst
  59. GRB060312: Swift UVOT observation
  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. GRB 060306: SOAR Ks Observations
  65. GRB060219: Liverpool Telescope observations
  66. GRB 060306: MAGNUM observations
  67. GRB060218: analysis of the XMM-Newton observation
  68. Swift/UVOT observations of GRB060306
  69. GRB 060306: Swift-XRT team refined analysis
  70. GRB 060306: Swift detection of a bright burst
  71. GRB060218: Ep,i - Eiso correlation
  72. GRB060223b: optical limit
  73. GRB060218/SN 2006aj: optical observation in V
  74. GRB060218/SN 2006aj: optical observation
  75. GRB 060121: HST observations
  76. GRB 060218 : GMRT observation [Correction and Improvement]
  77. GRB 060223b: Swift/UVOT Upper Limits
  78. GRB 060218/SN 2006aj: K-380 optical observations
  79. GRB 060223B: Swift XRT possible afterglow
  80. GRB 060218/SN 2006aj: ABT observations
  81. GRB 060218 : Radio upper limits from GMRT
  82. GRB 060204B: GETS early limit
  83. GRB 060218: Refined analysis of the radio afterglow
  84. GRB 060223A:Xinglong optical limits
  85. GRB 060223a: Swift/UVOT refined analysis
  86. GRB 060223: Swift XRT Team preliminary analysis
  87. GRB 060223B: Swift detection of a bright burst
  88. GRB 060223: Swift-BAT refined analysis
  89. Correction to GCN 4816 on GRB060218
  90. GRB060218: Optical brightening in V and R
  91. GRB 060223: Keck redshift
  92. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  93. GRB 060223: Swift detection of a burst
  94. Spectral properties of GRB060218/SN2006aj
  95. GRB 060218: Decline in r-band flux
  96. GRB 060218: spectroscopic observations
  97. GRB 060218: Likely an underluminous GRB
  98. GRB060218: Optical Spectroscopy of GRB-SN
  99. GRB 060219: SDSS galaxy inside XRT error circle
  100. GRB060218: UV Detection and Light Curves

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