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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 060102: MDM Observation
  2. Swift-BAT trigger 175653 is probably not a GRB
  3. GRB 060102: Swift-BAT refined analysis
  4. Time Correction to GRB 060102
  5. GRB 060102: Swift-BAT detection of a burst
  6. GRB051211B: optical observations
  7. GRB051227: SARA Observations
  8. GRB 051221B: Optical Observations with Kuiper 1.54m
  9. GRB 051227: Likely host galaxy underlying afterglow position
  10. GRB 051227: optical observation
  11. GRB051221B: Radio observations
  12. GRB 051221A: VLA Radio Observations
  13. GRB051227: Radio Observations
  14. GRB 051227: Confirmed fading from Gemini observations
  15. GRB051227: further analysis of VLT images
  16. GRB 051227: optical afterglow
  17. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  18. GRB 051227: Gemini observations
  19. GRB 051227: Keck Spectroscopy
  20. GRB 051227: Magellan r'-band Imaging/Astrometry
  21. GRB 051227: refined analysis of VLT images
  22. GRB 051227: P60 Observations
  23. GRB 051227: MDM Observation
  24. GRB 051227: R-band object in the XRT error circle
  25. GRB 051227: Joint Swift-HETE Spectral Analysis
  26. GRB 051227: XRT refined analysis
  27. GRB 051227: Further analysis of the Swift-BAT burst
  28. GRB 051227: Refined analysis of the Swift-BAT burst
  29. GRB051227: SDSS pre-burst observations
  30. GRB 051227, optical observation
  31. GRB 051227: Swift detection of a burst
  32. GRB051117B: optical observation
  33. IBAS_alert n. 2719 : not a real GRB
  34. Konus-Wind observation of GRB 051221A
  35. GRB051221A: Suzaku WAM observation of the prompt emission
  36. GRB 051221A: MDM Optical Observations
  37. GRB051016: analysis of the XMM-Newton observation
  38. GRB 051221A: Detection at 251nm with Swift UVOT
  39. GRB 051221A: Chandra Afterglow Position
  40. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  41. GRB 051221B: ROTSE-III Optical Limits
  42. GRB 051221B: TAROT optical limits
  43. GRB 051221A: WSRT Radio Observations
  44. GRB 051221: Redshift from Gemini
  45. GRB 051221: Continued fading of optical afterglow
  46. GRB 051221B: Refined analysis of the Swift-BAT burst
  47. Possible GRB 051221B: MDM Optical Detection
  48. GRB 051221A: RAPTOR Fading Counterpart Constraint
  49. GRB 051221B: BOOTES optical observations.
  50. Possible GRB 051221B: Swift XRT position
  51. GRB 051211A: Evidence This Is a Short Burst from Analysis of Spectral
  52. Swift-BAT detection of a possible burst
  53. GRB 051221: Discovery of fading optical afterglow
  54. GRB 051221: Swift XRT refined analysis
  55. GRB 051221: Swift/UVOT upper limits
  56. GRB 051221: Possible nearby cluster
  57. GRB 051221: No variability in Gemini data
  58. GRB 051221: Correction to GCN #4368
  59. GRB 051221: Gemini observations
  60. GRB 051221: Improved astrometry of the IR counterpart
  61. GRB051221: K-band source
  62. GRB 051221: XRT position
  63. GRB 051221: Refined analysis of the Swift-BAT short hard burst
  64. GRB 051221: IR Observations at GRB+1hr
  65. GRB 051221: Swift detection of a bright short burst
  66. Refined analysis of the SWIFT J1626.6-5156
  67. Swift-BAT discovery of hard x-ray transient SWIFT J1626.6-5156
  68. Refined analysis of the Swift-BAT detection of the RS CVn star II Peg
  69. GRB051211A (=H3979): Refined Analysis
  70. GRB 051211B: optical afterglow
  71. Swift detection of an RS CVn flare star
  72. GRB051211A: possible optical candidate
  73. Swift Trigger 172767 is not a GRB
  74. GRB 051215: near-infrared observations
  75. GRB051215 - SDSS pre-burst observations
  76. GRB 051215: Swift detection of a possible burst
  77. GRB 051215: A short GRB in a cluster?
  78. GRB051211B: Probable radio afterglow
  79. GRB051105: optical observations
  80. GRB 051213: Swift-BAT refined analysis
  81. GRB051211B: XRT refined analysis
  82. GRB 051211B, optical observation
  83. GRB 051213: Swift-BAT detection of a burst
  84. GRB 051211a: RTT150 optical observations
  85. GRB051211B, RBO optical observations
  86. GRB 051211A: Swift/UVOT upper limits
  87. GRB 051211B: Swift/UVOT upper limits - correction
  88. GRB 051211B: Swift/UVOT upper limits
  89. GRB 051211A,optical observation
  90. GRB 051211B: Swift XRT confirmation of the afterglow
  91. GRB051211B: Liverpool Telescope observation
  92. GRB 051211b: RTT150 optical observations
  93. GRB051211b: P60 Observations
  94. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  95. GRB 051211B: Swift XRT Observations
  96. GRB 051210: Swift/UVOT upper limits
  97. GRB 051210: Magellan Imaging
  98. GRB 051211: TAROT optical limits
  99. GRB 051211B: a possible optical detection by TAROT
  100. GRB 051211B: a long GRB detected by INTEGRAL

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