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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"

35947 results found.

  1. GRB050421: Radio Observations
  2. GRB 050421: Swift-UVOT observation
  3. GRB 050421: IR Observations
  4. GRB 050421: Swift-BAT refined analysis
  5. GRB 050421: ROTSE-III Optical Limits
  6. GRB 050421: NIR observations re-examination
  7. GRB 050421: early Swift XRT analysis results
  8. GRB 050421: NIR observations
  9. GRB050421: P60 Observations
  10. GRB 050421: BOOTES-2 simultaneous optical observations
  11. GRB 050421: Optical observations at the INT
  12. GRB 050416b: Tentative Swift XRT Position
  13. GRB 050315: potential host galaxy
  14. GRB 050412: Chandra observations
  15. GRB050416A, optical observations
  16. GRB 050418: Swift-BAT refined analysis
  17. Swift-BAT detection of the bright and long GRB 050418
  18. GRB 050416: Mitsume optical observation
  19. GRB 050416 : optical observation at Xinglong observatory
  20. GRB 050416B: optical observations
  21. GRB 050416b: Swift-BAT refined analysis
  22. GRB 050416b: LCO observations
  23. GRB 050416b: LCO observations
  24. GRB050416B: IR observations
  25. GRB 050416: Swift/UVOT refined analysis
  26. Swift-BAT detection of GRB 050416b
  27. IBAS GRB Alert # 2463: not a GRB
  28. GRB050412: Radio Observations
  29. GRB 050416: Swift/UVOT detection of afterglow emission
  30. GRB 050416: Swift-BAT refined analysis
  31. GRB 050416: ART observations
  32. GRB 050416,optical observation
  33. GRB 050416: KAIT observations
  34. GRB050416: P200 NIR Observations
  35. GRB 050416: Swift XRT Position
  36. GRB 050416: Radio observations
  37. Confirmation of OT for GRB050416
  38. GRB050416: P60 Afterglow Candidate
  39. Swift BAT/XRT Detection of GRB 050416
  40. GRB 050412: Subaru observations
  41. GRB 050408: RTT150 optical observations
  42. GRB 050412: PROMPT VRcIc Observations
  43. GRB 050408: Kuiper 1.5m observations
  44. GRB 050412: optical limit
  45. GRB 050412: optical observations
  46. GRB 050408: refined XRT analysis, no jet break seen yet
  47. GRB 050412: early Swift XRT analysis results
  48. GRB 050412 : XingLong optical observation
  49. GRB 050412: Swift-BAT refined analysis
  50. GRB 050412: ANU 2.3m observations
  51. GRB 050412: Early Optical/Ultraviolet Observations with
  52. GRB 050412: retraction of UVOT transient report
  53. GRB 050412: UVOT transient not in XRT error circle
  54. GRB 050408: SDSS Field Calibration
  55. GRB 050412: Optical limit
  56. GRB 050412: LCO Optical Observations
  57. GRB 050412: Optical observations
  58. GRB050412: P60 Observations
  59. GRB 050412: Swift XRT Position
  60. GRB050412: optical limit before and during GRB
  61. GRB 050412: LCO optical observations
  62. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  63. GRB 050412: IR and Optical observations
  64. GRB 050412: IR Observations
  65. GRB050408: Radio Observations
  66. GRB 050401: Optical limit
  67. GRB 050408: Optical limit
  68. GRB050410: P60 Observations
  69. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  70. GRB 050410, optical observations
  71. GRB 050408: PROMPT VRcIc Observations
  72. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  73. GRB 050410 R band Optical Observations
  74. GRB050410 : Null detection report
  75. GRB 050410, optical observations
  76. GRB050410: Radio Observations
  77. GRB 050408: Swift XRT measurement of possible jet break
  78. GRB050410: MASTER optical observations
  79. GRB 050410: Early observations with Swift-UVOT
  80. Swift-BAT detection of GRB 050410
  81. GRB 050410: Swift XRT Position
  82. GRB 050408: Retraction of Proposed Host Galaxy
  83. GRB 050408: Inconsistency of host galaxy identification
  84. GRB 050408: Subaru Observations
  85. GRB 050408: WIDGET simultaneous optical observations
  86. GRB 050408: SOAR UBVRc Observations
  87. GRB 050408: Properties of the Host Galaxy
  88. GRB 050408: Mercator Optical Observations
  89. GRB050408: Radio Observations
  90. GRB 050408: Swift XRT analysis
  91. GRB 050408, SMARTS optical/IR afterglow observations
  92. GRB 050408: Optical limit at 20 min after the burst
  93. GRB 050408, optical observations
  94. GRB 050408: Moderate-resolution Gemini Spectroscopy
  95. GRB 050408,optical observation
  96. GRB 050408 Optical Observations
  97. GRB 050408: Emission and absorption redshift
  98. GRB 050408: Mercator Optical Observations
  99. GRB 050408: Magellan astrometry and photometry
  100. GRB 050408: First Optical observations with TFOSC at the RTT150

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