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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"

22088 results found.

  1. GRB060502: Super-LOTIS Observations
  2. GRB 060502: P60 Afterglow Confirmation
  3. GRB 060502: Swift detection of a burst with an optical counterpart
  4. GRB060501: P60 imaging and afterglow candidate
  5. GRB 060501: ROTSE-III Optical Limits
  6. GRB 060501: Swift detection of a burst
  7. IPN triangulation of GRB060429 (short/hard)
  8. GRB060428B - SDSS Pre-Burst Observations
  9. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  10. GRB 060428B: MDM Observations
  11. GRB 060428A: PROMPT Observations
  12. GRB060428B: Swift XRT Team refined analysis
  13. GRB 060427B: IPN localization of a short hard burst
  14. GRB 060428B: Refined analysis of the Swift-BAT burst
  15. GRB 060428B: Xinglong I-band limit
  16. GRB 060428B: KAIT observations
  17. GRB 051117A: Bright host galaxy not confirmed
  18. GRB060428A: Swift/UVOT observations.
  19. GRB060428B, optical observation
  20. GRB 060428b : Kiso R-band limit
  21. GRB060427:MASTER optical limit
  22. GRB 060428b: Optical afterglow candidate
  23. GRB 060428B: Swift detection of a burst
  24. GRB 060427: NIR observations
  25. GRB060427: Xinglong optical Observations
  26. GRB 060428: Swift detection of a burst
  27. GRB 060427: Swift/UVOT upper limits.
  28. GRB060425:MASTER survey observations
  29. GRB 060427, optical observation
  30. GRB 060427: Swift detection of a burst
  31. GRB 060424: Swift detection of a burst
  32. GRB 060421: TTT Observations
  33. Swift-BAT detection of Mrk 421
  34. GRB060421: Swift/UVOT observations
  35. GRB 060421: Swift-XRT refined analysis
  36. GRB 060418: prediction of t_break
  37. Konus-Wind observation of GRB 060418
  38. GRB(?)060421:MASTER optical limit
  39. GRB(?) 060421: Swift detection of a burst
  40. GRB 060418: Radio Observations
  41. GRB060418, BVRcIc field calibration
  42. GRB060418: Swift/UVOT Observations
  43. GRB060418: Optical Observations
  44. GRB 060418: FRAM early afterglow observation
  45. VLT/UVES observations of GRB060418
  46. GRB 060418, SMARTS continuing afterglow observations
  47. GRB 060418, SMARTS optical/IR afterglow observations
  48. GRB060418 : LT optical afterglow observation
  49. GRB 060418: REM candidate afterglow
  50. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  51. GRB060413: Swift/UVOT upper limits
  52. GRB 060413: REM NIR Observations
  53. SGR 1900+14: Swift detection of an outburst
  54. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  55. GRB060403: optical observations
  56. GRB 060403 Optical observations
  57. GRB 060403: MITSuME optical observation
  58. GRB060403: Optical Limit
  59. GRB 060403: Swift/UVOT upper limits
  60. SGR 1900+14: BAT observations
  61. GRB 060403: Refined analysis of the Swift-BAT burst
  62. GRB 060403: Swift detection of a burst
  63. HETE trigger H4044: RTT150 optical observations
  64. GRB060331: Swift/UVOT upper limits
  65. Swift XRT observations of the HETE transient H4043
  66. H4043, an unusual high-energy transient observed by HETE
  67. GRB 060322: LNA optical limit
  68. INTEGRAL and XMM ToO observations of SGR1900+14
  69. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  70. SGR 1900+14: Swift-BAT detection of a bright outburst
  71. GRB 060323 : WIDGET simultaneous optical observations
  72. GRB 060323: Early optical observation at Xinglong
  73. GRB 060322: Confirmation of Swift XRT afterglow
  74. SGR 1900+14: Swift detection of renewed activity
  75. GRB060323: NOT optical observations
  76. GRB 060322: IAC80 optical observations
  77. GRB 060322: Swift XRT afterglow candidate
  78. GRB060323: P60 Observations
  79. GRB 060323: Swift/UVOT Observations
  80. GRB 060323: optical afterglow confirmed
  81. GRB060323: NOT observations
  82. GRB 060323: Optical Observations
  83. GRB 060323: optical observations at TNG
  84. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  85. GRB060323, optical observation
  86. GRB060323 - SDSS Pre-Burst Observations
  87. GRB 060323: Swift detection of a burst with a possible optical afterglow
  88. GRB 060322: Swift-BAT detection of a 200-sec burst
  89. GRB 060218/SN 2006aj, LNA optical observation
  90. GRB060218: Refined photometric calibration of comparison stars
  91. GRB 060319: WHT K-band candidate afterglow
  92. GRB060319: Swift/UVOT upper limits
  93. GRB060319: MASTER limit
  94. GRB 060319 optical observations at TNG
  95. GRB060319 : Liverpool Telescope optical limit
  96. GRB060319: MASTER optical observation
  97. GRB060319 - SDSS Pre-burst Observations
  98. GRB 060319: Swift detection of a burst
  99. GRB060313: Radio Observations
  100. GRB 060313: early afterglow NIR upper limits with REM

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