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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"
  1. IBAS Alert n. 3422: not a GRB
  2. GRB 060729: An update on the Swift XRT and UVOT observations
  3. GRB060717: optical observations
  4. GRB060807: Optical limiting magnitudes
  5. GRB 060805B: optical observation at Sierra Nevada
  6. GRB 060805B: XRT Team Analysis
  7. VLA Upper Limit on Outburst of SGR 1806-20
  8. GRB060806 is similar to previous activity of SGR1806-20
  9. GRB 060807: UVOT Upper limits
  10. GRB 060807: afterglow confirmation
  11. GRB 060807: XRT Team refined analysis
  12. GRB 060807: K- and R-band observations
  13. GRB 060807: Refined analysis of the Swift-BAT burst
  14. GRB060807: optical afterglow candidate
  15. GRB060806 = SGR1806-20
  16. GRB 060805B: RHESSI Spectral Fit
  17. GRB060807: optical upper limit in white light
  18. IPN triangulation of GRB060806 (long, exceptionally bright)
  19. GRB060807 - SDSS Pre-burst Observations
  20. GRB 060805B: X-ray Afterglow Detection, Spectral/Spatial/Temporal Properties
  21. GRB 060805B: Swift/UVOT Upper Limits
  22. GRB 060807, optical observation
  23. GRB 060807: Kanazawa R-band observation
  24. GRB 060807: optical limit
  25. GRB 060807: Swift detection of a burst
  26. GRB 060801: Second Epoch WSRT Radio Observations
  27. IPN triangulation of GRB060805B
  28. GRB060805 Liverpool Telescope observations
  29. GRB 060805: optical upper limit in R
  30. GRB 060805: XRT Team Refined Analysis
  31. GRB 060805: Swift-BAT Refined Analysis
  32. GRB 060805: Swift/UVOT Upper Limits
  33. GRB 060805: P60 Observations
  34. GRB 060805: KAIT observations
  35. GRB 060805 - SDSS Pre-Burst Observations
  36. GRB 060805: Swift detection of a burst
  37. GRB 060804: Swift UVOT observations
  38. GRB 060804: Swift-XRT Team Refined Analysis
  39. GRB 060804: Refined analysis of the Swift-BAT burst
  40. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  41. GRB 060728: Upper limits of the X-ray emission
  42. GRB 060801: no variability of optical sources
  43. IBAS Alert 3418: not a GRB
  44. GRB 060801: WSRT Radio Observations
  45. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  46. GRB060801: Radio Observations
  47. GRB 051109B: Bright spiral host galaxy at low redshift
  48. GRB 060801: optical observations at FORS2/VLT
  49. GRB060801: Swift/UVOT Upper Limits
  50. GRB 060801: optical observations at Hanle and Calar Alto
  51. GRB060801: optical upper limit in R
  52. GRB 060801: Swift XRT refined analysis
  53. GRB 060801: Refined analysis of the Swift-BAT short hard burst
  54. GRB 060801, optical observation
  55. GRB 060801: Kanazawa Optical Observation
  56. GRB 060801: Swift detection of a short burst
  57. GRB060729: ROTSE-III Observations of the Slow Optical Decay
  58. GRB 060218 / SN 2006aj Nebular Spectrum
  59. IBAS Alert n. 3415: not a GRB
  60. Swift-BAT trigger 221873 is not a GRB or a Transient
  61. GRB 060729 redshift
  62. GRB 060719: TORTOREM optical upper limits
  63. GRB 060729: Swift/UVOT Detections
  64. GRB 060729: Refined analysis of the Swift-BAT burst
  65. GRB 060729: Swift-XRT refined analysis
  66. GRB 060729 : Planned XMM-Newton observation
  67. GRB 060729: Swift/UVOT Observations
  68. GRB 060729: ROTSE-III Detection of Optical Counterpart
  69. GRB 060729: Swift detection of a burst with an UVOT optical counterpart
  70. GRB 060728: Swift/UVOT Upper Limits
  71. GRB 060728: Refined analysis of the Swift-BAT burst
  72. GRB 060728, SMARTS optical/IR observations
  73. Swift/XRT preliminary analysis
  74. GRB 060728: Swift detection of a burst
  75. GRB060614 ATCA Radio Limits
  76. GRB 060218 (SN 2006aj): IR afterglow detection six months after the
  77. GRB 060714: Swift/UVOT Observations
  78. GRB060719: prompt NIR observations with REM
  79. GRB 060714: NOT observations
  80. GRB 060719: near-infrared afterglow
  81. GRB 060719: correction to the coordinates reported in GCN 5347
  82. GRB 060522: VLA observation
  83. GRB 060719: Swift/UVOT Upper Limits
  84. GRB 060719: VLT/ISAAC observations
  85. GRB 060719: Refined analysis of the Swift-BAT burst
  86. GRB 060719: XRT refined analysis
  87. GRB 060719: further analysis of VLT observations
  88. GRB 060719: optical limit by Pi-of-the-Sky
  89. GRB060719: FRAM early follow-up limit
  90. GRB 060719: prompt PROMPT observations
  91. GRB060719: REM NIR Observations
  92. GRB 060719: Continued LCO optical observations
  93. GRB 060719: VLT observations
  94. GRB 060719: LCO optical observations
  95. GRB 060719: Swift detection of a burst
  96. GRB 060717: Swift XRT refined analysis
  97. GRB 060714: OA fading and a possible host detection
  98. GRB060714: optical observations
  99. GRB 060717: NOT observations
  100. GRB 060714: Refined analysis of the Swift-BAT burst

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