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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. GRB 060805: KAIT observations
  2. GRB 060805 - SDSS Pre-Burst Observations
  3. GRB 060805: Swift detection of a burst
  4. GRB 060804: Swift UVOT observations
  5. GRB 060804: Swift-XRT Team Refined Analysis
  6. GRB 060804: Refined analysis of the Swift-BAT burst
  7. GRB 060804: Swift detection of a burst with a possible UVOT counterpart
  8. GRB 060728: Upper limits of the X-ray emission
  9. GRB 060801: no variability of optical sources
  10. IBAS Alert 3418: not a GRB
  11. GRB 060801: WSRT Radio Observations
  12. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  13. GRB060801: Radio Observations
  14. GRB 051109B: Bright spiral host galaxy at low redshift
  15. GRB 060801: optical observations at FORS2/VLT
  16. GRB060801: Swift/UVOT Upper Limits
  17. GRB 060801: optical observations at Hanle and Calar Alto
  18. GRB060801: optical upper limit in R
  19. GRB 060801: Swift XRT refined analysis
  20. GRB 060801: Refined analysis of the Swift-BAT short hard burst
  21. GRB 060801, optical observation
  22. GRB 060801: Kanazawa Optical Observation
  23. GRB 060801: Swift detection of a short burst
  24. GRB060729: ROTSE-III Observations of the Slow Optical Decay
  25. GRB 060218 / SN 2006aj Nebular Spectrum
  26. IBAS Alert n. 3415: not a GRB
  27. Swift-BAT trigger 221873 is not a GRB or a Transient
  28. GRB 060729 redshift
  29. GRB 060719: TORTOREM optical upper limits
  30. GRB 060729: Swift/UVOT Detections
  31. GRB 060729: Refined analysis of the Swift-BAT burst
  32. GRB 060729: Swift-XRT refined analysis
  33. GRB 060729 : Planned XMM-Newton observation
  34. GRB 060729: Swift/UVOT Observations
  35. GRB 060729: ROTSE-III Detection of Optical Counterpart
  36. GRB 060729: Swift detection of a burst with an UVOT optical counterpart
  37. GRB 060728: Swift/UVOT Upper Limits
  38. GRB 060728: Refined analysis of the Swift-BAT burst
  39. GRB 060728, SMARTS optical/IR observations
  40. Swift/XRT preliminary analysis
  41. GRB 060728: Swift detection of a burst
  42. GRB060614 ATCA Radio Limits
  43. GRB 060218 (SN 2006aj): IR afterglow detection six months after the
  44. GRB 060714: Swift/UVOT Observations
  45. GRB060719: prompt NIR observations with REM
  46. GRB 060714: NOT observations
  47. GRB 060719: near-infrared afterglow
  48. GRB 060719: correction to the coordinates reported in GCN 5347
  49. GRB 060522: VLA observation
  50. GRB 060719: Swift/UVOT Upper Limits
  51. GRB 060719: VLT/ISAAC observations
  52. GRB 060719: Refined analysis of the Swift-BAT burst
  53. GRB 060719: XRT refined analysis
  54. GRB 060719: further analysis of VLT observations
  55. GRB 060719: optical limit by Pi-of-the-Sky
  56. GRB060719: FRAM early follow-up limit
  57. GRB 060719: prompt PROMPT observations
  58. GRB060719: REM NIR Observations
  59. GRB 060719: Continued LCO optical observations
  60. GRB 060719: VLT observations
  61. GRB 060719: LCO optical observations
  62. GRB 060719: Swift detection of a burst
  63. GRB 060717: Swift XRT refined analysis
  64. GRB 060714: OA fading and a possible host detection
  65. GRB060714: optical observations
  66. GRB 060717: NOT observations
  67. GRB 060714: Refined analysis of the Swift-BAT burst
  68. GRB 060717 optical upper limit
  69. GRB060717: Swift/UVOT upper limits
  70. GRB 060717: Swift XRT refined position
  71. GRB 060717: Swift-BAT refined analysis
  72. GRB060717 - SDSS Pre-burst Observations
  73. GRB 060714: REM infrared observations
  74. GRB 060717, optical observation
  75. GRB 060717: Swift detection of a burst
  76. GRB060714: correction to GCN 5324
  77. GRB060714: optical observations
  78. GRB 060714, SMARTS optical/IR afterglow observation
  79. GRB 060714 : Liverpool Telescope Observations
  80. GRB 060714: Swift XRT refined analysis
  81. GRB 060714: OA redshift
  82. GRB 060708: VLT spectroscopy
  83. GRB060708: MARGE low resolution spectrum observations
  84. GRB060714: optical observations
  85. Swift-BAT trigger 219136 is not a GRB
  86. Correction to Circular 5314: Circular refers to GRB 060714
  87. GRB060707 possible optical confirmation
  88. Swift trigger 219136 is probably not a GRB
  89. GRB 060714, optical observation
  90. GRB 060714: Swift detection of a burst with an UVOT optical afterglow
  91. GRB 060605: SkyNet Optical Limits
  92. GRB060712: P60 Observations
  93. GRB 060712: XRT refined analysis
  94. GRB 060712: Swift/UVOT Upper Limits
  95. GRB060526: optical observations
  96. GRB 060712: XRT refined position
  97. GRB 060712: Refined analysis of the Swift-BAT burst
  98. GRB060712: MASTER optical observation
  99. GRB120706: MASTER optical observation
  100. GRB 060712: Swift detection of a burst

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