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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. GRB050813: Maidanak I-band observations
  2. GRB 050822: Swift-BAT refined analysis
  3. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  4. GRB050820B at FRAM
  5. GRB050820A: RTT150 optical observations
  6. GRB 050820a - corrections to GCN 3846
  7. Swift/UVOT UV Photometry of GRB 050820B
  8. GRB 050822: ROTSE-III Prompt Optical Limits
  9. GRB 050822: Swift detection of a long burst
  10. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  11. GRB050820A: Radio Observation
  12. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  13. GRB050820a BVRcIc field photometry
  14. GRB050820B XMM-Newton observation
  15. GRB 050820a: NIR Observations by WIRO
  16. GRB 050820B: Swift XRT position
  17. GRB050820B: Planned XMM-Newton observation
  18. SUBJECT: GRB050820B: Refined analysis of the Swift-BAT burst
  19. GRB050820B: BAT-Swift detection of a bright GRB
  20. Swift/UVOT photometry of GRB050820
  21. GRB050820: refined XRT analysis
  22. GRB 050820: Early RAPTOR detections
  23. GRB 050820 Swift-BAT refined analysis
  24. GRB 050820: P60 Temporal Decay Index
  25. GRB 050820: High Resolution Spectroscopy from Keck
  26. GRB050819: refined XRT analysis
  27. GRB050819: RTT150 optical observations
  28. GRB 050820: Swift detection of a GRB
  29. GRB050820: Optical afterglow from P60
  30. GRB 050819 Swift-BAT refined analysis
  31. GRB050819: Swift XRT position
  32. GRB050819: Swift-BAT detection of a weak burst
  33. Swift-BAT trigger 150993 is not a GRB
  34. Swift Trigger 150823 is HETE J1900.1-2455
  35. GRB 050817: Optical observations
  36. GRB 050815: Radio Observation
  37. GRB050814: Radio Observation
  38. GRB050817: Negative Optical Observations
  39. GRB050817: Swift-BAT Detection of a burst
  40. GRB 050814: continued fading
  41. GRB050815: Optical afterglow detection by Swift UVOT
  42. GRB050815: XRT refined analysis
  43. GRB 050813: Radio Observations
  44. GRB050815: Refined analysis of the Swift-BAT burst
  45. GRB 050815: ROTSE-III Optical Limits
  46. GRB050815: Swift XRT afterglow localization
  47. GRB050815: Swift-BAT detection of a burst
  48. GRB 050730: Third Epoch WSRT Radio Observations
  49. GRB050814: Fading red source
  50. GRB 050813: Gemini Spectra Revisited
  51. GRB050814: P60 Optical Afterglow Candidate
  52. GRB 050813: Non-fading of afterglow candidate
  53. GRB 050814: XRT refined analysis
  54. GRB050814: SWIFT/UVOT observation
  55. GRB050814: Refined analysis of the Swift-BAT burst
  56. GRB050813: Gemini Imaging
  57. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  58. GRB 050814: Swift XRT Afterglow Localization
  59. GRB 050814: Swift detection of a burst
  60. GRB 050813: Magellan detection of a high redshift galaxy cluster
  61. GRB050813: RTT150 optical observations
  62. GRB 050813: I-band observations
  63. GRB050813, SDSS pre-burst observations
  64. GRB 050813: KAIT optical limit
  65. GRB 050813: Swift-BAT refined analysis
  66. GRB 050813: Photometry of object in XRT error circle
  67. GRB050813: SWIFT/UVOT observation
  68. GRB 050813: Swift XRT afterglow localization
  69. RBO GRB 050714A and GRB 050716 observations
  70. GRB 050813: Possible Short Swift-BAT GRB
  71. GRB050813 (Swift 150139): P60 Observations
  72. Swift-BAT trigger 150131 is not a GRB
  73. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  74. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  75. GRB050803: CrAO optical observations, no OT candidate
  76. Detection of an intermediate burst from SGR 1806-20 on August 8
  77. GRB 050730: WSRT Radio Observations
  78. GRB 050803: PROMPT BVRcIc Observations
  79. GRB 050807: ROTSE-III Optical Limits
  80. GRB 050730, optical observation
  81. GRB050805b: CrAO optical limit
  82. GRB050805a : Null detection report
  83. GRB050730, optical observations
  84. GRB050803, optical observations
  85. Swift-BAT trigger 149118 is very likely not a GRB
  86. Retraction of Swift Trigger 149131 (GRB 050805B)
  87. GRB 050805b: OHP optical limits
  88. GRB 050805b: TAROT optical limits
  89. GRB050805b: MASTER optical observations
  90. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  91. GRB050805a: MASTER optical candidat
  92. Swift-BAT trigger 149118 is probably not a GRB
  93. GRB050802: TNG optical observations
  94. GRB050803: Radio Observation
  95. GRB 050803: RTT150 optical observations
  96. GRB050801: Radio Observation
  97. GRB050730: Radio Detection
  98. GRB050803: CrAO optical observations, possible OT candidate
  99. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  100. GRB 050803: Keck Observations

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