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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. HETE Trigger 4043: ROTSE-III Optical Limits
  2. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  3. H4043, an unusual high-energy transient observed by HETE
  4. GRB 060322: LNA optical limit
  5. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  6. INTEGRAL and XMM ToO observations of SGR1900+14
  7. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  8. SGR 1900+14: Swift-BAT detection of a bright outburst
  9. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  10. GRB 060323 : WIDGET simultaneous optical observations
  11. GRB 060323: Early optical observation at Xinglong
  12. GRB060218, optical observations
  13. GRB 060322: Confirmation of Swift XRT afterglow
  14. GRB 060211A: optical observation
  15. GRB060323: optical limit
  16. GRB060211B: optical observation
  17. SGR 1900+14: CORRECTION to GCN 4923
  18. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  19. SGR 1900+14: Swift detection of renewed activity
  20. GRB060323: NOT optical observations
  21. GRB 060322: IAC80 optical observations
  22. GRB 060322: Swift XRT afterglow candidate
  23. GRB060323: P60 Observations
  24. GRB 060323: Swift/UVOT Observations
  25. GRB 060323: optical afterglow confirmed
  26. GRB060323: NOT observations
  27. GRB 060323: Optical Observations
  28. GRB 060323: Tautenburg OT candidate retraction
  29. GRB 060323: Refined analysis of the Swift-BAT burst
  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 060322: Refined analysis of the Swift-BAT burst
  35. GRB060323, optical observation
  36. GRB060323 - SDSS Pre-Burst Observations
  37. GRB 060323: Swift detection of a burst with a possible optical afterglow
  38. GRB 060322: Swift-BAT detection of a 200-sec burst
  39. GRB060219: optical observation
  40. GRB060206: optical observation
  41. GRB060218/SN2006aj: optical observations
  42. GRB 060218/SN 2006aj, LNA optical observation
  43. GRB060218: Refined photometric calibration of comparison stars
  44. GRB 060319: WHT K-band candidate afterglow
  45. GRB 060319: IAC-80 optical observations
  46. GRB060319: Swift XRT refined analysis
  47. GRB060319: Swift/UVOT upper limits
  48. GRB 060319: Re-analysis of TNG data
  49. GRB060319: MASTER limit
  50. GRB 060319: Swift-BAT refined analysis
  51. GRB 060319 optical observations at TNG
  52. GRB060319 : Liverpool Telescope optical limit
  53. GRB060319: MASTER optical observation
  54. GRB060319 - SDSS Pre-burst Observations
  55. GRB060319: Swift/XRT position
  56. GRB 060319: Swift detection of a burst
  57. GRB060313: Radio Observations
  58. GRB 060313: early afterglow NIR upper limits with REM
  59. IBAS Alert n. 3221: not a GRB
  60. Konus-Wind observation of GRB 060313
  61. GRB060313: SSO 40inch Observations
  62. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  63. GRB 060313: PROMPT Observations
  64. GRB 060313: Swift/UVOT Observations
  65. GRB060313:Gemini South Observations
  66. GRB 060313: Swift-XRT team refined analysis
  67. GRB060313: optical observations of the afterglow candidate
  68. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  69. GRB 060313, SMARTS optical counterpart?
  70. GRB 060313: Possible optical counterpart
  71. GRB 060313: Swift XRT position
  72. GRB 060313, SMARTS optical/IR observations
  73. GRB060313: optical and near infrared observations with REM
  74. GRB 060313: Swift-BAT detection of a bright short hard burst
  75. GRB060218: SARA Observations of SN2006aj
  76. GRB060312: Swift UVOT observation
  77. GRB 060312: Refined analysis of the Swift-BAT burst
  78. GRB 060218/SN 2006aj, high resolution spectra
  79. GRB 060312: Swift XRT team refined analysis
  80. GRB060306: APO Ks-band Imaging Observations
  81. GRB 060312: ROTSE-III Optical Limits
  82. GRB 060312: Swift detection of a burst
  83. IBAS Alert n. 3218 : not a real GRB
  84. GRB 060306: SOAR Ks Observations
  85. Bright short hard GRB 060303: IPN localization and Konus spectrum
  86. GRB060219: Liverpool Telescope observations
  87. GRB 060306: MAGNUM observations
  88. GRB060218: analysis of the XMM-Newton observation
  89. Swift/UVOT observations of GRB060306
  90. GRB 060306: Swift-BAT refined analysis
  91. GRB 060306: Swift-XRT team refined analysis
  92. GRB 060306: PROMPT Observations
  93. GRB 060306: Swift detection of a bright burst
  94. GRB 060218: RTT150 optical observations
  95. GRB060218: Ep,i - Eiso correlation
  96. GRB060218: R-band CCD photmetry
  97. GRB060223b: optical limit
  98. GRB060218/SN 2006aj: optical observation in V
  99. GRB060218/SN 2006aj: optical observation
  100. GRB 060121: HST observations

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