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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"

31730 results found.

  1. GRB060427: Swift XRT Team refined analysis
  2. GRB060418: Swift XRT Team Further Refined Analysis
  3. GRB 060427, optical observation
  4. GRB060424: optical afterglow detection
  5. GRB060418: Further Analysis of MIKE Spectroscopy
  6. GRB 060424: Refined analysis of the Swift-BAT burst
  7. GRB 060421: TTT Observations
  8. OT 060420: Likely Not a New Cosmic Transient
  9. No OT 060420 in MASCOT images
  10. GRB060421: Swift/UVOT observations
  11. GRB 060421: Swift-BAT Refined Analysis
  12. GRB 060421: Swift-XRT refined analysis
  13. GRB 060418: prediction of t_break
  14. GRB060418: optical observations
  15. Konus-Wind observation of GRB 060418
  16. Possible GRB060421: BART limits
  17. Erratum of GCN 4983 for GRB 060418 IR follow-up
  18. GRB 060418 : IR afterglow observations
  19. GRB 060418 : Lulin Optical follow-up
  20. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  21. GRB 060418: Radio Observations
  22. GRB060418, BVRcIc field calibration
  23. GRB060418: Swift/UVOT Observations
  24. GRB060418: Optical Observations
  25. GRB 060418: FRAM early afterglow observation
  26. GRB 060418: Refined Analysis of the Swift-BAT burst
  27. VLT/UVES observations of GRB060418
  28. GRB 060418, SMARTS continuing afterglow observations
  29. GRB 060418: PROMPT Detections
  30. GRB 060418, SMARTS optical/IR afterglow observations
  31. GRB060418: Magellan/MIKE Spectroscopic Redshift
  32. GRB060418 : LT optical afterglow observation
  33. GRB 060418: REM candidate afterglow
  34. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  35. GRB060413: Swift/UVOT upper limits
  36. GRB 060413: REM NIR Observations
  37. GRB 060413: Refined analysis of the Swift-BAT burst
  38. GRB 060413: Watcher UBVR observations
  39. GRB 060413: XRT refined analysis
  40. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  41. GRB 060413: Swift detection of a burst
  42. GRB060403: optical observations
  43. GRB 060403 Optical observations
  44. GRB 060403: MITSuME optical observation
  45. GRB060403: Optical Limit
  46. GRB060403: XRT refined analysis
  47. GRB 060403: Swift/UVOT upper limits
  48. SGR 1900+14: BAT observations
  49. GRB 060403: Refined analysis of the Swift-BAT burst
  50. GRB060403: Swift XRT refined position
  51. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  52. HETE trigger H4044: RTT150 optical observations
  53. GRB060331: Swift/UVOT upper limits
  54. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  55. Swift XRT observations of the HETE transient H4043
  56. HETE Trigger 4043: ROTSE-III Optical Limits
  57. H4043, an unusual high-energy transient observed by HETE
  58. GRB 060322: LNA optical limit
  59. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  60. INTEGRAL and XMM ToO observations of SGR1900+14
  61. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  62. GRB 060323 : WIDGET simultaneous optical observations
  63. GRB 060323: Early optical observation at Xinglong
  64. GRB060218, optical observations
  65. GRB 060322: Confirmation of Swift XRT afterglow
  66. GRB 060211A: optical observation
  67. GRB060323: optical limit
  68. GRB060211B: optical observation
  69. SGR 1900+14: CORRECTION to GCN 4923
  70. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  71. GRB060323: NOT optical observations
  72. GRB 060322: Swift XRT afterglow candidate
  73. GRB060323: P60 Observations
  74. GRB 060323: Swift/UVOT Observations
  75. GRB 060323: optical afterglow confirmed
  76. GRB060323: NOT observations
  77. GRB 060323: Optical Observations
  78. GRB 060323: Tautenburg OT candidate retraction
  79. GRB 060323: Refined analysis of the Swift-BAT burst
  80. GRB 060323: optical observations at TNG
  81. GRB 060323: Swift XRT refined analysis
  82. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  83. GRB 060323: Swift/XRT position
  84. GRB 060322: Refined analysis of the Swift-BAT burst
  85. GRB060323, optical observation
  86. GRB060206: optical observation
  87. GRB060218/SN2006aj: optical observations
  88. GRB 060218/SN 2006aj, LNA optical observation
  89. GRB060218: Refined photometric calibration of comparison stars
  90. GRB 060319: WHT K-band candidate afterglow
  91. GRB060319: Swift XRT refined analysis
  92. GRB060319: Swift/UVOT upper limits
  93. GRB 060319: Re-analysis of TNG data
  94. GRB060319: MASTER limit
  95. GRB 060319: Swift-BAT refined analysis
  96. GRB 060319 optical observations at TNG
  97. GRB060319 : Liverpool Telescope optical limit
  98. GRB060319 - SDSS Pre-burst Observations
  99. GRB060319: Swift/XRT position
  100. GRB060313: Radio Observations

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