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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 060425: IPN localization and KW spectrum of a short, hard burst
  2. An interactive program for GRB pseudo-redshift computations
  3. GRB060424: optical afterglow detection
  4. GRB060418: Further Analysis of MIKE Spectroscopy
  5. GRB 060424: Refined analysis of the Swift-BAT burst
  6. GRB 060424: Swift detection of a burst
  7. GRB 060421: TTT Observations
  8. OT 060420: Likely Not a New Cosmic Transient
  9. No OT 060420 in MASCOT images
  10. Swift-BAT detection of Mrk 421
  11. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  12. GRB060421: Swift/UVOT observations
  13. GRB 060421: Swift-BAT Refined Analysis
  14. GRB 060421: Swift-XRT refined analysis
  15. GRB 060418: prediction of t_break
  16. GRB060418: optical observations
  17. Konus-Wind observation of GRB 060418
  18. GRB(?)060421:MASTER optical limit
  19. GRB(?)060421 : XRT position
  20. Possible GRB060421: BART limits
  21. GRB(?) 060421: Swift detection of a burst
  22. Erratum of GCN 4983 for GRB 060418 IR follow-up
  23. GRB 060418 : IR afterglow observations
  24. GRB 060418 : Lulin Optical follow-up
  25. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  26. GRB 060418: Radio Observations
  27. GRB060418, BVRcIc field calibration
  28. GRB060418: Swift/UVOT Observations
  29. GRB060418: Optical Observations
  30. GRB 060418: FRAM early afterglow observation
  31. GRB 060418: Refined Analysis of the Swift-BAT burst
  32. VLT/UVES observations of GRB060418
  33. GRB060418: Swift XRT Team Refined Analysis
  34. GRB 060418, SMARTS continuing afterglow observations
  35. GRB 060418: PROMPT Detections
  36. GRB 060418, SMARTS optical/IR afterglow observations
  37. GRB060418: Magellan/MIKE Spectroscopic Redshift
  38. GRB060418 : LT optical afterglow observation
  39. GRB 060418: REM candidate afterglow
  40. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  41. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  42. GRB060413: Swift/UVOT upper limits
  43. GRB 060413: REM NIR Observations
  44. SGR 1900+14: Swift detection of an outburst
  45. GRB 060413: Refined analysis of the Swift-BAT burst
  46. GRB 060413: Watcher UBVR observations
  47. GRB 060413: XRT refined analysis
  48. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  49. GRB 060413: Swift detection of a burst
  50. GRB060403: optical observations
  51. GRB 060403 Optical observations
  52. GRB 060403: MITSuME optical observation
  53. GRB060403: Optical Limit
  54. GRB060403: XRT refined analysis
  55. GRB 060403: Swift/UVOT upper limits
  56. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  57. SGR 1900+14: BAT observations
  58. GRB 060403: Refined analysis of the Swift-BAT burst
  59. GRB060403: Swift XRT refined position
  60. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  61. GRB 060403: Swift detection of a burst
  62. HETE trigger H4044: RTT150 optical observations
  63. GRB060331: Swift/UVOT upper limits
  64. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  65. Swift XRT observations of the HETE transient H4043
  66. HETE Trigger 4043: ROTSE-III Optical Limits
  67. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  68. H4043, an unusual high-energy transient observed by HETE
  69. GRB 060322: LNA optical limit
  70. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  71. INTEGRAL and XMM ToO observations of SGR1900+14
  72. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  73. SGR 1900+14: Swift-BAT detection of a bright outburst
  74. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  75. GRB 060323 : WIDGET simultaneous optical observations
  76. GRB 060323: Early optical observation at Xinglong
  77. GRB060218, optical observations
  78. GRB 060322: Confirmation of Swift XRT afterglow
  79. GRB 060211A: optical observation
  80. GRB060323: optical limit
  81. GRB060211B: optical observation
  82. SGR 1900+14: CORRECTION to GCN 4923
  83. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  84. SGR 1900+14: Swift detection of renewed activity
  85. GRB060323: NOT optical observations
  86. GRB 060322: IAC80 optical observations
  87. GRB 060322: Swift XRT afterglow candidate
  88. GRB060323: P60 Observations
  89. GRB 060323: Swift/UVOT Observations
  90. GRB 060323: optical afterglow confirmed
  91. GRB060323: NOT observations
  92. GRB 060323: Optical Observations
  93. GRB 060323: Tautenburg OT candidate retraction
  94. GRB 060323: Refined analysis of the Swift-BAT burst
  95. GRB 060323: optical observations at TNG
  96. GRB 060323: Swift XRT refined analysis
  97. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  98. GRB 060323: Swift/XRT position
  99. GRB 060322: Refined analysis of the Swift-BAT burst
  100. GRB060323, optical observation

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