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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"

36140 results found.

  1. GRB 050412: Chandra observations
  2. GRB050416A, optical observations
  3. GRB 050418: Swift-BAT refined analysis
  4. Swift-BAT detection of the bright and long GRB 050418
  5. GRB 050416: Mitsume optical observation
  6. GRB 050416 : optical observation at Xinglong observatory
  7. GRB 050416B: optical observations
  8. GRB 050416b: Swift-BAT refined analysis
  9. GRB 050416b: LCO observations
  10. GRB 050416b: LCO observations
  11. GRB050416B: IR observations
  12. GRB 050416: Swift/UVOT refined analysis
  13. Swift-BAT detection of GRB 050416b
  14. IBAS GRB Alert # 2463: not a GRB
  15. GRB050412: Radio Observations
  16. GRB 050416: Swift/UVOT detection of afterglow emission
  17. GRB 050416: Swift-BAT refined analysis
  18. GRB 050416: ART observations
  19. GRB 050416,optical observation
  20. GRB 050416: KAIT observations
  21. GRB050416: P200 NIR Observations
  22. GRB 050416: Swift XRT Position
  23. GRB 050416: Radio observations
  24. Confirmation of OT for GRB050416
  25. GRB050416: P60 Afterglow Candidate
  26. Swift BAT/XRT Detection of GRB 050416
  27. GRB 050412: Subaru observations
  28. GRB 050408: RTT150 optical observations
  29. GRB 050412: PROMPT VRcIc Observations
  30. GRB 050408: Kuiper 1.5m observations
  31. GRB 050412: optical limit
  32. GRB 050412: optical observations
  33. GRB 050408: refined XRT analysis, no jet break seen yet
  34. GRB 050412: early Swift XRT analysis results
  35. GRB 050412 : XingLong optical observation
  36. GRB 050412: Swift-BAT refined analysis
  37. GRB 050412: ANU 2.3m observations
  38. GRB 050412: Early Optical/Ultraviolet Observations with
  39. GRB 050412: retraction of UVOT transient report
  40. GRB 050412: UVOT transient not in XRT error circle
  41. GRB 050408: SDSS Field Calibration
  42. GRB 050412: Optical limit
  43. GRB 050412: LCO Optical Observations
  44. GRB 050412: Optical observations
  45. GRB050412: P60 Observations
  46. GRB 050412: Swift XRT Position
  47. GRB050412: optical limit before and during GRB
  48. GRB 050412: LCO optical observations
  49. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  50. GRB 050412: IR and Optical observations
  51. GRB 050412: IR Observations
  52. GRB050408: Radio Observations
  53. GRB 050401: Optical limit
  54. GRB 050408: Optical limit
  55. GRB050410: P60 Observations
  56. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  57. GRB 050410, optical observations
  58. GRB 050408: PROMPT VRcIc Observations
  59. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  60. GRB 050410 R band Optical Observations
  61. GRB050410 : Null detection report
  62. GRB 050410, optical observations
  63. GRB050410: Radio Observations
  64. GRB 050408: Swift XRT measurement of possible jet break
  65. GRB050410: MASTER optical observations
  66. GRB 050410: Early observations with Swift-UVOT
  67. Swift-BAT detection of GRB 050410
  68. GRB 050410: Swift XRT Position
  69. GRB 050408: Retraction of Proposed Host Galaxy
  70. GRB 050408: Inconsistency of host galaxy identification
  71. GRB 050408: Subaru Observations
  72. GRB 050408: WIDGET simultaneous optical observations
  73. GRB 050408: SOAR UBVRc Observations
  74. GRB 050408: Properties of the Host Galaxy
  75. GRB 050408: Mercator Optical Observations
  76. GRB050408: Radio Observations
  77. GRB 050408: Swift XRT analysis
  78. GRB 050408, SMARTS optical/IR afterglow observations
  79. GRB 050408: Optical limit at 20 min after the burst
  80. GRB 050408, optical observations
  81. GRB 050408: Moderate-resolution Gemini Spectroscopy
  82. GRB 050408,optical observation
  83. GRB 050408 Optical Observations
  84. GRB 050408: Emission and absorption redshift
  85. GRB 050408: Mercator Optical Observations
  86. GRB 050408: Magellan astrometry and photometry
  87. GRB 050408: First Optical observations with TFOSC at the RTT150
  88. GRB 050408: steepening of the optical decay
  89. GRB 050408: Optical afterglow confirmed
  90. GRB 050408: opitcal observation
  91. GRB 050408, optical observations
  92. GRB 050408 optical candidate
  93. GRB 050408: Swift XRT Position
  94. GRB 050408: ROTSE-III Optical Limits
  95. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  96. GRB050408: MASTER optical observations
  97. GRB050401: Radio Detection
  98. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  99. GRB 050406: Magellan optical observations
  100. GRB 050406: early Swift XRT analysis results

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