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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. GRB 060403: Swift/UVOT upper limits
  2. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  3. SGR 1900+14: BAT observations
  4. GRB 060403: Refined analysis of the Swift-BAT burst
  5. GRB060403: Swift XRT refined position
  6. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  7. GRB 060403: Swift detection of a burst
  8. HETE trigger H4044: RTT150 optical observations
  9. GRB060331: Swift/UVOT upper limits
  10. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  11. Swift XRT observations of the HETE transient H4043
  12. HETE Trigger 4043: ROTSE-III Optical Limits
  13. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  14. H4043, an unusual high-energy transient observed by HETE
  15. GRB 060322: LNA optical limit
  16. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  17. INTEGRAL and XMM ToO observations of SGR1900+14
  18. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  19. SGR 1900+14: Swift-BAT detection of a bright outburst
  20. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  21. GRB 060323 : WIDGET simultaneous optical observations
  22. GRB 060323: Early optical observation at Xinglong
  23. GRB060218, optical observations
  24. GRB 060322: Confirmation of Swift XRT afterglow
  25. GRB 060211A: optical observation
  26. GRB060323: optical limit
  27. GRB060211B: optical observation
  28. SGR 1900+14: CORRECTION to GCN 4923
  29. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  30. SGR 1900+14: Swift detection of renewed activity
  31. GRB060323: NOT optical observations
  32. GRB 060322: IAC80 optical observations
  33. GRB 060322: Swift XRT afterglow candidate
  34. GRB060323: P60 Observations
  35. GRB 060323: Swift/UVOT Observations
  36. GRB 060323: optical afterglow confirmed
  37. GRB060323: NOT observations
  38. GRB 060323: Optical Observations
  39. GRB 060323: Tautenburg OT candidate retraction
  40. GRB 060323: Refined analysis of the Swift-BAT burst
  41. GRB 060323: optical observations at TNG
  42. GRB 060323: Swift XRT refined analysis
  43. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  44. GRB 060323: Swift/XRT position
  45. GRB 060322: Refined analysis of the Swift-BAT burst
  46. GRB060323, optical observation
  47. GRB060323 - SDSS Pre-Burst Observations
  48. GRB 060323: Swift detection of a burst with a possible optical afterglow
  49. GRB 060322: Swift-BAT detection of a 200-sec burst
  50. GRB060219: optical observation
  51. GRB060206: optical observation
  52. GRB060218/SN2006aj: optical observations
  53. GRB 060218/SN 2006aj, LNA optical observation
  54. GRB060218: Refined photometric calibration of comparison stars
  55. GRB 060319: WHT K-band candidate afterglow
  56. GRB 060319: IAC-80 optical observations
  57. GRB060319: Swift XRT refined analysis
  58. GRB060319: Swift/UVOT upper limits
  59. GRB 060319: Re-analysis of TNG data
  60. GRB060319: MASTER limit
  61. GRB 060319: Swift-BAT refined analysis
  62. GRB 060319 optical observations at TNG
  63. GRB060319 : Liverpool Telescope optical limit
  64. GRB060319: MASTER optical observation
  65. GRB060319 - SDSS Pre-burst Observations
  66. GRB060319: Swift/XRT position
  67. GRB 060319: Swift detection of a burst
  68. GRB060313: Radio Observations
  69. GRB 060313: early afterglow NIR upper limits with REM
  70. IBAS Alert n. 3221: not a GRB
  71. Konus-Wind observation of GRB 060313
  72. GRB060313: SSO 40inch Observations
  73. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  74. GRB 060313: PROMPT Observations
  75. GRB 060313: Swift/UVOT Observations
  76. GRB060313:Gemini South Observations
  77. GRB 060313: Swift-XRT team refined analysis
  78. GRB060313: optical observations of the afterglow candidate
  79. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  80. GRB 060313, SMARTS optical counterpart?
  81. GRB 060313: Possible optical counterpart
  82. GRB 060313: Swift XRT position
  83. GRB 060313, SMARTS optical/IR observations
  84. GRB060313: optical and near infrared observations with REM
  85. GRB 060313: Swift-BAT detection of a bright short hard burst
  86. GRB060218: SARA Observations of SN2006aj
  87. GRB060312: Swift UVOT observation
  88. GRB 060312: Refined analysis of the Swift-BAT burst
  89. GRB 060218/SN 2006aj, high resolution spectra
  90. GRB 060312: Swift XRT team refined analysis
  91. GRB060306: APO Ks-band Imaging Observations
  92. GRB 060312: ROTSE-III Optical Limits
  93. GRB 060312: Swift detection of a burst
  94. IBAS Alert n. 3218 : not a real GRB
  95. GRB 060306: SOAR Ks Observations
  96. Bright short hard GRB 060303: IPN localization and Konus spectrum
  97. GRB060219: Liverpool Telescope observations
  98. GRB 060306: MAGNUM observations
  99. GRB060218: analysis of the XMM-Newton observation
  100. Swift/UVOT observations of GRB060306

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