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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').
  1. GRB 050820B: Swift XRT position
  2. GRB050820B: Planned XMM-Newton observation
  3. GRB050820B: Refined analysis of the Swift-BAT burst
  4. GRB050820B: BAT-Swift detection of a bright GRB
  5. Swift/UVOT photometry of GRB050820
  6. GRB050820: refined XRT analysis
  7. GRB 050820: Early RAPTOR detections
  8. GRB 050820 Swift-BAT refined analysis
  9. GRB 050820: P60 Temporal Decay Index
  10. GRB 050820: High Resolution Spectroscopy from Keck
  11. GRB050819: refined XRT analysis
  12. GRB050819: RTT150 optical observations
  13. GRB 050820: Swift detection of a GRB
  14. GRB050820: Optical afterglow from P60
  15. GRB 050819 Swift-BAT refined analysis
  16. GRB050819: Swift XRT position
  17. GRB050819: Swift-BAT detection of a weak burst
  18. Swift-BAT trigger 150993 is not a GRB
  19. Swift Trigger 150823 is HETE J1900.1-2455
  20. GRB 050817: Optical observations
  21. GRB 050815: Radio Observation
  22. GRB050814: Radio Observation
  23. GRB050817: Negative Optical Observations
  24. GRB050817: Swift-BAT Detection of a burst
  25. GRB 050814: continued fading
  26. GRB050815: Optical afterglow detection by Swift UVOT
  27. GRB050815: XRT refined analysis
  28. GRB 050813: Radio Observations
  29. GRB050815: Refined analysis of the Swift-BAT burst
  30. GRB 050815: ROTSE-III Optical Limits
  31. GRB050815: Swift XRT afterglow localization
  32. GRB050815: Swift-BAT detection of a burst
  33. GRB 050730: Third Epoch WSRT Radio Observations
  34. GRB050814: Fading red source
  35. GRB 050813: Gemini Spectra Revisited
  36. GRB050814: P60 Optical Afterglow Candidate
  37. GRB 050813: Non-fading of afterglow candidate
  38. GRB 050814: XRT refined analysis
  39. GRB050814: SWIFT/UVOT observation
  40. GRB050814: Refined analysis of the Swift-BAT burst
  41. GRB050813: Gemini Imaging
  42. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  43. GRB 050814: Swift XRT Afterglow Localization
  44. GRB 050814: Swift detection of a burst
  45. GRB 050813: Magellan detection of a high redshift galaxy cluster
  46. GRB050813: RTT150 optical observations
  47. GRB 050813: I-band observations
  48. GRB050813, SDSS pre-burst observations
  49. GRB 050813: KAIT optical limit
  50. GRB 050813: Swift-BAT refined analysis
  51. GRB 050813: Photometry of object in XRT error circle
  52. GRB050813: SWIFT/UVOT observation
  53. GRB 050813: Swift XRT afterglow localization
  54. RBO GRB 050714A and GRB 050716 observations
  55. GRB 050813: Possible Short Swift-BAT GRB
  56. GRB050813 (Swift 150139): P60 Observations
  57. Swift-BAT trigger 150131 is not a GRB
  58. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  59. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  60. GRB050803: CrAO optical observations, no OT candidate
  61. Detection of an intermediate burst from SGR 1806-20 on August 8
  62. GRB 050730: WSRT Radio Observations
  63. GRB 050803: PROMPT BVRcIc Observations
  64. GRB 050807: ROTSE-III Optical Limits
  65. GRB 050730, optical observation
  66. GRB050805b: CrAO optical limit
  67. GRB050805a : Null detection report
  68. GRB050730, optical observations
  69. GRB050803, optical observations
  70. Swift-BAT trigger 149118 is very likely not a GRB
  71. Retraction of Swift Trigger 149131 (GRB 050805B)
  72. GRB 050805b: OHP optical limits
  73. GRB 050805b: TAROT optical limits
  74. GRB050805b: MASTER optical observations
  75. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  76. GRB050805a: MASTER optical candidat
  77. Swift-BAT trigger 149118 is probably not a GRB
  78. GRB050802: TNG optical observations
  79. GRB050803: Radio Observation
  80. GRB 050803: RTT150 optical observations
  81. GRB050801: Radio Observation
  82. GRB050730: Radio Detection
  83. GRB050803: CrAO optical observations, possible OT candidate
  84. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  85. GRB 050803: Keck Observations
  86. GRB 050803: Swift-BAT refined analysis
  87. GRB 050802.422: Fading of the afterglow and detection of the host
  88. GRB050803: MASTER further analys
  89. GRB 050803, optical observations
  90. GRB 050803: Magellan Observations
  91. GRB 050803: early Swift XRT analysis results
  92. GRB 050803: TAROT optical limits
  93. GRB050803: MASTER optical observations
  94. GRB050802: Tentative absorption redshift
  95. GRB050803: Swift-BAT detection of a very long burst
  96. GCN GRB observation 050713A
  97. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  98. GRB 050802: Swift/UVOT optical and UV detections
  99. GRB050802: CrAO optical observations
  100. GRB050801: Unchanged decay slope

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