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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. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  2. Swift XRT observations of the HETE transient H4043
  3. HETE Trigger 4043: ROTSE-III Optical Limits
  4. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  5. H4043, an unusual high-energy transient observed by HETE
  6. GRB 060322: LNA optical limit
  7. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  8. INTEGRAL and XMM ToO observations of SGR1900+14
  9. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  10. SGR 1900+14: Swift-BAT detection of a bright outburst
  11. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  12. GRB 060323 : WIDGET simultaneous optical observations
  13. GRB 060323: Early optical observation at Xinglong
  14. GRB060218, 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: CORRECTION to GCN 4923
  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: Refined analysis of the Swift-BAT burst
  32. GRB 060323: optical observations at TNG
  33. GRB 060323: Swift XRT refined analysis
  34. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  35. GRB 060323: Swift/XRT position
  36. GRB 060322: Refined analysis of the Swift-BAT burst
  37. GRB060323, optical observation
  38. GRB060323 - SDSS Pre-Burst Observations
  39. GRB 060323: Swift detection of a burst with a possible optical afterglow
  40. GRB 060322: Swift-BAT detection of a 200-sec burst
  41. GRB060219: optical observation
  42. GRB060206: optical observation
  43. GRB060218/SN2006aj: optical observations
  44. GRB 060218/SN 2006aj, LNA optical observation
  45. GRB060218: Refined photometric calibration of comparison stars
  46. GRB 060319: WHT K-band candidate afterglow
  47. GRB 060319: IAC-80 optical observations
  48. GRB060319: Swift XRT refined analysis
  49. GRB060319: Swift/UVOT upper limits
  50. GRB 060319: Re-analysis of TNG data
  51. GRB060319: MASTER limit
  52. GRB 060319: Swift-BAT refined analysis
  53. GRB 060319 optical observations at TNG
  54. GRB060319 : Liverpool Telescope optical limit
  55. GRB060319: MASTER optical observation
  56. GRB060319 - SDSS Pre-burst Observations
  57. GRB060319: Swift/XRT position
  58. GRB 060319: Swift detection of a burst
  59. GRB060313: Radio Observations
  60. GRB 060313: early afterglow NIR upper limits with REM
  61. IBAS Alert n. 3221: not a GRB
  62. Konus-Wind observation of GRB 060313
  63. GRB060313: SSO 40inch Observations
  64. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  65. GRB 060313: PROMPT Observations
  66. GRB 060313: Swift/UVOT Observations
  67. GRB060313:Gemini South Observations
  68. GRB 060313: Swift-XRT team refined analysis
  69. GRB060313: optical observations of the afterglow candidate
  70. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  71. GRB 060313, SMARTS optical counterpart?
  72. GRB 060313: Possible optical counterpart
  73. GRB 060313: Swift XRT position
  74. GRB 060313, SMARTS optical/IR observations
  75. GRB060313: optical and near infrared observations with REM
  76. GRB 060313: Swift-BAT detection of a bright short hard burst
  77. GRB060218: SARA Observations of SN2006aj
  78. GRB060312: Swift UVOT observation
  79. GRB 060312: Refined analysis of the Swift-BAT burst
  80. GRB 060218/SN 2006aj, high resolution spectra
  81. GRB 060312: Swift XRT team refined analysis
  82. GRB060306: APO Ks-band Imaging Observations
  83. GRB 060312: ROTSE-III Optical Limits
  84. GRB 060312: Swift detection of a burst
  85. IBAS Alert n. 3218 : not a real GRB
  86. GRB 060306: SOAR Ks Observations
  87. Bright short hard GRB 060303: IPN localization and Konus spectrum
  88. GRB060219: Liverpool Telescope observations
  89. GRB 060306: MAGNUM observations
  90. GRB060218: analysis of the XMM-Newton observation
  91. Swift/UVOT observations of GRB060306
  92. GRB 060306: Swift-BAT refined analysis
  93. GRB 060306: Swift-XRT team refined analysis
  94. GRB 060306: PROMPT Observations
  95. GRB 060306: Swift detection of a bright burst
  96. GRB 060218: RTT150 optical observations
  97. GRB060218: Ep,i - Eiso correlation
  98. GRB060218: R-band CCD photmetry
  99. GRB060223b: optical limit
  100. GRB060218/SN 2006aj: optical observation in V

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