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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 060807: Swift detection of a burst
  2. GRB 060801: Second Epoch WSRT Radio Observations
  3. IPN triangulation of GRB060805B
  4. GRB060805 Liverpool Telescope observations
  5. GRB 060805: optical upper limit in R
  6. GRB 060805: XRT Team Refined Analysis
  7. GRB 060805: Swift-BAT Refined Analysis
  8. GRB 060805: Swift/UVOT Upper Limits
  9. GRB 060805: P60 Observations
  10. GRB 060805: KAIT observations
  11. GRB 060805 - SDSS Pre-Burst Observations
  12. GRB 060805: Swift detection of a burst
  13. GRB 060804: Swift UVOT observations
  14. GRB 060804: Swift-XRT Team Refined Analysis
  15. GRB 060804: Refined analysis of the Swift-BAT burst
  16. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  17. GRB 060728: Upper limits of the X-ray emission
  18. GRB 060801: no variability of optical sources
  19. IBAS Alert 3418: not a GRB
  20. GRB 060801: WSRT Radio Observations
  21. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  22. GRB060801: Radio Observations
  23. GRB 051109B: Bright spiral host galaxy at low redshift
  24. GRB 060801: optical observations at FORS2/VLT
  25. GRB060801: Swift/UVOT Upper Limits
  26. GRB 060801: optical observations at Hanle and Calar Alto
  27. GRB060801: optical upper limit in R
  28. GRB 060801: Swift XRT refined analysis
  29. GRB 060801: Refined analysis of the Swift-BAT short hard burst
  30. GRB 060801, optical observation
  31. GRB 060801: Kanazawa Optical Observation
  32. GRB 060801: Swift detection of a short burst
  33. GRB060729: ROTSE-III Observations of the Slow Optical Decay
  34. GRB 060218 / SN 2006aj Nebular Spectrum
  35. IBAS Alert n. 3415: not a GRB
  36. Swift-BAT trigger 221873 is not a GRB or a Transient
  37. GRB 060729 redshift
  38. GRB 060719: TORTOREM optical upper limits
  39. GRB 060729: Swift/UVOT Detections
  40. GRB 060729: Refined analysis of the Swift-BAT burst
  41. GRB 060729: Swift-XRT refined analysis
  42. GRB 060729 : Planned XMM-Newton observation
  43. GRB 060729: Swift/UVOT Observations
  44. GRB 060729: ROTSE-III Detection of Optical Counterpart
  45. GRB 060729: Swift detection of a burst with an UVOT optical counterpart
  46. GRB 060728: Swift/UVOT Upper Limits
  47. GRB 060728: Refined analysis of the Swift-BAT burst
  48. GRB 060728, SMARTS optical/IR observations
  49. Swift/XRT preliminary analysis
  50. GRB 060728: Swift detection of a burst
  51. GRB060614 ATCA Radio Limits
  52. GRB 060218 (SN 2006aj): IR afterglow detection six months after the
  53. GRB 060714: Swift/UVOT Observations
  54. GRB060719: prompt NIR observations with REM
  55. GRB 060714: NOT observations
  56. GRB 060719: near-infrared afterglow
  57. GRB 060719: correction to the coordinates reported in GCN 5347
  58. GRB 060522: VLA observation
  59. GRB 060719: Swift/UVOT Upper Limits
  60. GRB 060719: VLT/ISAAC observations
  61. GRB 060719: Refined analysis of the Swift-BAT burst
  62. GRB 060719: XRT refined analysis
  63. GRB 060719: further analysis of VLT observations
  64. GRB 060719: optical limit by Pi-of-the-Sky
  65. GRB060719: FRAM early follow-up limit
  66. GRB 060719: prompt PROMPT observations
  67. GRB060719: REM NIR Observations
  68. GRB 060719: Continued LCO optical observations
  69. GRB 060719: VLT observations
  70. GRB 060719: LCO optical observations
  71. GRB 060719: Swift detection of a burst
  72. GRB 060717: Swift XRT refined analysis
  73. GRB 060714: OA fading and a possible host detection
  74. GRB060714: optical observations
  75. GRB 060717: NOT observations
  76. GRB 060714: Refined analysis of the Swift-BAT burst
  77. GRB 060717 optical upper limit
  78. GRB060717: Swift/UVOT upper limits
  79. GRB 060717: Swift XRT refined position
  80. GRB 060717: Swift-BAT refined analysis
  81. GRB060717 - SDSS Pre-burst Observations
  82. GRB 060714: REM infrared observations
  83. GRB 060717, optical observation
  84. GRB 060717: Swift detection of a burst
  85. GRB060714: correction to GCN 5324
  86. GRB060714: optical observations
  87. GRB 060714, SMARTS optical/IR afterglow observation
  88. GRB 060714 : Liverpool Telescope Observations
  89. GRB 060714: Swift XRT refined analysis
  90. GRB 060714: OA redshift
  91. GRB 060708: VLT spectroscopy
  92. GRB060708: MARGE low resolution spectrum observations
  93. GRB060714: optical observations
  94. Swift-BAT trigger 219136 is not a GRB
  95. Correction to Circular 5314: Circular refers to GRB 060714
  96. GRB060707 possible optical confirmation
  97. Swift trigger 219136 is probably not a GRB
  98. GRB 060714, optical observation
  99. GRB 060714: Swift detection of a burst with an UVOT optical afterglow
  100. GRB 060605: SkyNet Optical Limits

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