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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"

45417 results found.

  1. Confirmation of OT for GRB050416
  2. GRB050416: P60 Afterglow Candidate
  3. Swift BAT/XRT Detection of GRB 050416
  4. GRB 050412: Subaru observations
  5. GRB 050408: RTT150 optical observations
  6. GRB050408: optical observation
  7. GRB 050412: PROMPT VRcIc Observations
  8. GRB 050408: Kuiper 1.5m observations
  9. GRB 050412: optical limit
  10. GRB 050412: optical observations
  11. GRB 050408: refined XRT analysis, no jet break seen yet
  12. GRB 050412: early Swift XRT analysis results
  13. GRB 050412 : XingLong optical observation
  14. GRB 050412: Swift-BAT refined analysis
  15. GRB 050412: ANU 2.3m observations
  16. GRB 050412: Early Optical/Ultraviolet Observations with
  17. GRB 050412: retraction of UVOT transient report
  18. GRB 050412: UVOT transient not in XRT error circle
  19. GRB 050408: SDSS Field Calibration
  20. GRB 050412: Optical limit
  21. GRB 050412: LCO Optical Observations
  22. GRB 050412: Optical observations
  23. GRB050412: P60 Observations
  24. GRB 050412: Swift XRT Position
  25. GRB050412: optical limit before and during GRB
  26. GRB 050412: LCO optical observations
  27. GRB050412: ROTSE-III Optical Limits
  28. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  29. GRB 050412: IR and Optical observations
  30. GRB 050412: IR Observations
  31. GRB050408: Radio Observations
  32. GRB 050401: Optical limit
  33. GRB 050408: Optical limit
  34. GRB050410: P60 Observations
  35. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  36. GRB 050410, optical observations
  37. GRB 050408: PROMPT VRcIc Observations
  38. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  39. GRB 050410 R band Optical Observations
  40. GRB050410 : Null detection report
  41. GRB 050410, optical observations
  42. GRB050410: Radio Observations
  43. GRB 050408: Swift XRT measurement of possible jet break
  44. GRB050410: MASTER optical observations
  45. GRB 050410: Early observations with Swift-UVOT
  46. Swift-BAT detection of GRB 050410
  47. GRB 050410: Swift XRT Position
  48. GRB 050408: Retraction of Proposed Host Galaxy
  49. GRB 050408: Inconsistency of host galaxy identification
  50. GRB 050408: Subaru Observations
  51. GRB 050408: WIDGET simultaneous optical observations
  52. GRB 050408: SOAR UBVRc Observations
  53. GRB 050408: Properties of the Host Galaxy
  54. GRB 050408: Mercator Optical Observations
  55. GRB050408: Radio Observations
  56. GRB 050408: Swift XRT analysis
  57. GRB 050408, SMARTS optical/IR afterglow observations
  58. GRB 050408: Optical limit at 20 min after the burst
  59. GRB 050408, optical observations
  60. GRB050408: REM NIR and Optical observation
  61. GRB 050408: Moderate-resolution Gemini Spectroscopy
  62. GRB 050408,optical observation
  63. GRB 050408 Optical Observations
  64. GRB 050408: Emission and absorption redshift
  65. GRB 050408: Mercator Optical Observations
  66. GRB 050408: Magellan astrometry and photometry
  67. GRB 050408: First Optical observations with TFOSC at the RTT150
  68. GRB 050408: steepening of the optical decay
  69. GRB 050408: Optical afterglow confirmed
  70. GRB 050408: opitcal observation
  71. GRB 050408, optical observations
  72. GRB 050408 optical candidate
  73. GRB 050408: Swift XRT Position
  74. GRB 050408: ROTSE-III Optical Limits
  75. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  76. GRB050408: MASTER optical observations
  77. GRB050401: Radio Detection
  78. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  79. GRB 050406: Magellan optical observations
  80. GRB 050406: early Swift XRT analysis results
  81. GRB 050406 BAT refined analysis
  82. GRB 050406: Early observations with Swift-UVOT
  83. GRB 050406: Swift XRT Position
  84. Swift-BAT detection of GRB 050406
  85. Konus-Wind observation of GRB 050401
  86. GRB050401: Radio observation at 610 MHz with GMRT
  87. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  88. GRB 050401: VLT spectroscopic redshift
  89. GRB 050401 Optical Observations
  90. GRB050401: Maidanak optical observation
  91. GRB 050401 BAT refined analysis
  92. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  93. GRB050401: TNG R-band observation
  94. GRB 050402A: IR Analysis
  95. GRB050402: XDSS counterpart
  96. GRB 050402A: IR Observations
  97. GRB 050402: Early observations with Swift-UVOT
  98. Swift Trigger 113225: P60 Observations
  99. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  100. GRB 050401: Optical afterglow confirmed

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