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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"

25905 results found.

  1. GRB 060211A: optical observation
  2. GRB060323: optical limit
  3. GRB060211B: optical observation
  4. SGR 1900+14: CORRECTION to GCN 4923
  5. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  6. SGR 1900+14: Swift detection of renewed activity
  7. GRB060323: NOT optical observations
  8. GRB 060322: IAC80 optical observations
  9. GRB 060322: Swift XRT afterglow candidate
  10. GRB060323: P60 Observations
  11. GRB 060323: Swift/UVOT Observations
  12. GRB 060323: optical afterglow confirmed
  13. GRB060323: NOT observations
  14. GRB 060323: Optical Observations
  15. GRB 060323: Tautenburg OT candidate retraction
  16. GRB 060323: Refined analysis of the Swift-BAT burst
  17. GRB 060323: optical observations at TNG
  18. GRB 060323: Swift XRT refined analysis
  19. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  20. GRB 060323: Swift/XRT position
  21. GRB 060322: Refined analysis of the Swift-BAT burst
  22. GRB060323 - SDSS Pre-Burst Observations
  23. GRB 060323: Swift detection of a burst with a possible optical afterglow
  24. GRB 060322: Swift-BAT detection of a 200-sec burst
  25. GRB060219: optical observation
  26. GRB060206: optical observation
  27. GRB 060319: WHT K-band candidate afterglow
  28. GRB 060319: IAC-80 optical observations
  29. GRB060319: Swift XRT refined analysis
  30. GRB060319: Swift/UVOT upper limits
  31. GRB060319: MASTER limit
  32. GRB 060319: Swift-BAT refined analysis
  33. GRB 060319 optical observations at TNG
  34. GRB060319 : Liverpool Telescope optical limit
  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. Konus-Wind observation of GRB 060313
  40. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  41. GRB 060313: PROMPT Observations
  42. GRB 060313: Swift/UVOT Observations
  43. GRB 060313: Swift-XRT team refined analysis
  44. GRB060313: optical observations of the afterglow candidate
  45. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  46. GRB 060313, SMARTS optical counterpart?
  47. GRB 060313: Possible optical counterpart
  48. GRB 060313: Swift XRT position
  49. GRB060313: optical and near infrared observations with REM
  50. GRB 060313: Swift-BAT detection of a bright short hard burst
  51. GRB060312: Swift UVOT observation
  52. GRB 060312: Refined analysis of the Swift-BAT burst
  53. GRB 060312: Swift XRT team refined analysis
  54. GRB060306: APO Ks-band Imaging Observations
  55. GRB 060312: ROTSE-III Optical Limits
  56. GRB 060312: Swift detection of a burst
  57. GRB 060306: SOAR Ks Observations
  58. Bright short hard GRB 060303: IPN localization and Konus spectrum
  59. GRB060219: Liverpool Telescope observations
  60. GRB 060306: MAGNUM observations
  61. GRB060218: analysis of the XMM-Newton observation
  62. Swift/UVOT observations of GRB060306
  63. GRB 060306: Swift-BAT refined analysis
  64. GRB 060306: Swift-XRT team refined analysis
  65. GRB 060306: Swift detection of a bright burst
  66. GRB060218: Ep,i - Eiso correlation
  67. GRB060223b: optical limit
  68. GRB060218/SN 2006aj: optical observation in V
  69. GRB060218/SN 2006aj: optical observation
  70. GRB 060121: HST observations
  71. GRB 060218 : GMRT observation [Correction and Improvement]
  72. GRB 060223b: Swift/UVOT Upper Limits
  73. GRB 060218/SN 2006aj: K-380 optical observations
  74. GRB 060223B: Swift XRT possible afterglow
  75. GRB 060218/SN 2006aj: ABT observations
  76. GRB 060218 : Radio upper limits from GMRT
  77. GRB 060204B: GETS early limit
  78. GRB 060218: Refined analysis of the radio afterglow
  79. GRB 060223B: Swift-BAT refined analysis
  80. GRB 060223a: Swift/UVOT refined analysis
  81. GRB 060223: Swift XRT Team preliminary analysis
  82. GRB 060218/SN 2006aj: Swift-BAT fluence and peak flux
  83. GRB 060223B: Swift detection of a bright burst
  84. GRB 060223: Swift-BAT refined analysis
  85. Correction to GCN 4816 on GRB060218
  86. GRB060218: Optical brightening in V and R
  87. GRB 060223: Keck redshift
  88. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  89. GRB 060223: Swift detection of a burst
  90. Spectral properties of GRB060218/SN2006aj
  91. GRB 060219: Swift-BAT refined analysis
  92. GRB 060218: Decline in r-band flux
  93. GRB 060218: spectroscopic observations
  94. GRB 060218: Further refined analysis of the Swift-BAT burst
  95. GRB 060218: Likely an underluminous GRB
  96. GRB060218: Optical Spectroscopy of GRB-SN
  97. GRB 060219: SDSS galaxy inside XRT error circle
  98. GRB060218: UV Detection and Light Curves
  99. GRB 060219: Swift/UVOT Upper Limits
  100. GRB 060219: Swift-XRT Team refined analysis

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