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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"

35343 results found.

  1. GRB 060428B: Xinglong I-band limit
  2. GRB 060428B: KAIT observations
  3. GRB060425:MASTER optical limit
  4. GRB 051117A: Bright host galaxy not confirmed
  5. GRB 060428A: Refined analysis of the Swift-BAT burst
  6. GRB 060428b : Kiso R-band limit
  7. GRB060427:MASTER optical limit
  8. GRB 060428b: Optical afterglow candidate
  9. GRB 060428B: Swift detection of a burst
  10. GRB 060427: NIR observations
  11. GRB 060428: Swift detection of a burst
  12. GRB 060427: NOT observations
  13. GRB 060427: Swift/UVOT upper limits.
  14. GRB 060427: Refined analysis of the Swift-BAT burst
  15. GRB060418: Swift XRT Team Further Refined Analysis
  16. GRB060425:MASTER survey observations
  17. GRB 060427, optical observation
  18. GRB 060427: Swift detection of a burst
  19. GRB 060425: IPN localization and KW spectrum of a short, hard burst
  20. An interactive program for GRB pseudo-redshift computations
  21. GRB060424: optical afterglow detection
  22. GRB060418: Further Analysis of MIKE Spectroscopy
  23. GRB 060424: Refined analysis of the Swift-BAT burst
  24. GRB 060424: Swift detection of a burst
  25. GRB 060421: TTT Observations
  26. GRB 060421: Swift-BAT Refined Analysis
  27. GRB 060421: Swift-XRT refined analysis
  28. GRB 060418: prediction of t_break
  29. GRB060418: optical observations
  30. Konus-Wind observation of GRB 060418
  31. GRB(?)060421:MASTER optical limit
  32. GRB(?)060421 : XRT position
  33. GRB(?) 060421: Swift detection of a burst
  34. Erratum of GCN 4983 for GRB 060418 IR follow-up
  35. GRB 060418 : IR afterglow observations
  36. GRB 060418 : Lulin Optical follow-up
  37. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  38. GRB 060418: Radio Observations
  39. GRB060418, BVRcIc field calibration
  40. GRB060418: Optical Observations
  41. GRB 060418: FRAM early afterglow observation
  42. GRB 060418: Refined Analysis of the Swift-BAT burst
  43. VLT/UVES observations of GRB060418
  44. GRB060418: Swift XRT Team Refined Analysis
  45. GRB 060418, SMARTS continuing afterglow observations
  46. GRB 060418: PROMPT Detections
  47. GRB 060418, SMARTS optical/IR afterglow observations
  48. GRB060418: Magellan/MIKE Spectroscopic Redshift
  49. GRB060418 : LT optical afterglow observation
  50. GRB 060418: REM candidate afterglow
  51. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  52. GRB 060413: REM NIR Observations
  53. GRB 060413: Refined analysis of the Swift-BAT burst
  54. GRB 060413: Watcher UBVR observations
  55. GRB 060413: XRT refined analysis
  56. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  57. GRB 060413: Swift detection of a burst
  58. GRB060403: optical observations
  59. GRB 060403 Optical observations
  60. GRB 060403: MITSuME optical observation
  61. GRB060403: XRT refined analysis
  62. GRB 060403: Swift/UVOT upper limits
  63. GRB 060403: Refined analysis of the Swift-BAT burst
  64. GRB 060403: Swift detection of a burst
  65. GRB 060322: LNA optical limit
  66. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  67. GRB 060323 : WIDGET simultaneous optical observations
  68. GRB 060323: Early optical observation at Xinglong
  69. GRB060218, optical observations
  70. GRB 060322: Confirmation of Swift XRT afterglow
  71. GRB 060211A: optical observation
  72. GRB060323: optical limit
  73. GRB060211B: optical observation
  74. GRB060323: NOT optical observations
  75. GRB 060322: IAC80 optical observations
  76. GRB 060322: Swift XRT afterglow candidate
  77. GRB 060323: Swift/UVOT Observations
  78. GRB 060323: optical afterglow confirmed
  79. GRB060323: NOT observations
  80. GRB 060323: Optical Observations
  81. GRB 060323: Tautenburg OT candidate retraction
  82. GRB 060323: Refined analysis of the Swift-BAT burst
  83. GRB 060323: optical observations at TNG
  84. GRB 060323: Swift XRT refined analysis
  85. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  86. GRB 060323: Swift/XRT position
  87. GRB 060322: Refined analysis of the Swift-BAT burst
  88. GRB060323 - SDSS Pre-Burst Observations
  89. GRB 060323: Swift detection of a burst with a possible optical afterglow
  90. GRB 060322: Swift-BAT detection of a 200-sec burst
  91. GRB060219: optical observation
  92. GRB060206: optical observation
  93. GRB060218/SN2006aj: optical observations
  94. GRB 060218/SN 2006aj, LNA optical observation
  95. GRB060218: Refined photometric calibration of comparison stars
  96. GRB 060319: WHT K-band candidate afterglow
  97. GRB 060319: IAC-80 optical observations
  98. GRB060319: Swift XRT refined analysis
  99. GRB 060319: Re-analysis of TNG data
  100. GRB060319: MASTER limit

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