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

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