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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"

16155 results found.

  1. GRB 060825: TAROT optical observations
  2. GRB060825: BOOTES-IR optical observations
  3. GRB 060729, SMARTS optical/IR observations
  4. GRB060814: Break in the XRT light curve
  5. GRB060813: Break in the XRT light curve
  6. GRB060805B: optical observations
  7. GRB060814: Swift/UVOT upper limits
  8. GRB 060814: VLT optical limits
  9. GRB 060814: TAROT optical observations
  10. GRB060813: Swift/UVOT upper limits
  11. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  12. GRB060807: Possible Highly Significant X-ray Emission Lines
  13. GRB060714: optical observations
  14. GRB 060729: An update on the Swift XRT and UVOT observations
  15. GRB060717: optical observations
  16. GRB060807: Optical limiting magnitudes
  17. GRB 060805B: optical observation at Sierra Nevada
  18. GRB 060805B: XRT Team Analysis
  19. GRB 060807: UVOT Upper limits
  20. GRB 060807: afterglow confirmation
  21. GRB 060807: K- and R-band observations
  22. GRB060807: optical afterglow candidate
  23. GRB060807: optical upper limit in white light
  24. GRB 060805B: X-ray Afterglow Detection, Spectral/Spatial/Temporal Properties
  25. GRB 060805B: Swift/UVOT Upper Limits
  26. GRB 060807, optical observation
  27. GRB 060807: optical limit
  28. GRB 060805: optical upper limit in R
  29. GRB 060805: Swift/UVOT Upper Limits
  30. GRB 060804: Swift UVOT observations
  31. GRB 060801: no variability of optical sources
  32. GRB 060801: WSRT Radio Observations
  33. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  34. GRB 051109B: Bright spiral host galaxy at low redshift
  35. GRB 060801: optical observations at FORS2/VLT
  36. GRB060801: Swift/UVOT Upper Limits
  37. GRB 060801: optical observations at Hanle and Calar Alto
  38. GRB060801: optical upper limit in R
  39. GRB 060801, optical observation
  40. GRB 060801: Kanazawa Optical Observation
  41. GRB060729: ROTSE-III Observations of the Slow Optical Decay
  42. GRB 060719: TORTOREM optical upper limits
  43. GRB 060729: Swift/UVOT Detections
  44. GRB 060729: Swift/UVOT Observations
  45. GRB 060729: ROTSE-III Detection of Optical Counterpart
  46. GRB 060729: Swift detection of a burst with an UVOT optical counterpart
  47. GRB 060728: Refined analysis of the Swift-BAT burst
  48. GRB 060728, SMARTS optical/IR observations
  49. GRB 060218 (SN 2006aj): IR afterglow detection six months after the
  50. GRB 060714: Swift/UVOT Observations
  51. GRB060719: prompt NIR observations with REM
  52. GRB 060714: NOT observations
  53. GRB 060719: near-infrared afterglow
  54. GRB 060719: optical limit by Pi-of-the-Sky
  55. GRB 060719: prompt PROMPT observations
  56. GRB 060719: Continued LCO optical observations
  57. GRB 060719: LCO optical observations
  58. GRB 060714: OA fading and a possible host detection
  59. GRB060714: optical observations
  60. GRB 060717: NOT observations
  61. GRB 060717 optical upper limit
  62. GRB 060717, optical observation
  63. GRB060714: optical observations
  64. GRB 060714, SMARTS optical/IR afterglow observation
  65. GRB 060714: Swift XRT refined analysis
  66. GRB 060714: OA redshift
  67. GRB 060708: VLT spectroscopy
  68. GRB060708: MARGE low resolution spectrum observations
  69. GRB060714: optical observations
  70. Correction to Circular 5314: Circular refers to GRB 060714
  71. GRB060707 possible optical confirmation
  72. GRB 060714, optical observation
  73. GRB 060714: Swift detection of a burst with an UVOT optical afterglow
  74. GRB 060605: SkyNet Optical Limits
  75. GRB060526: optical observations
  76. GRB060712: MASTER optical observation
  77. GRB120706: MASTER optical observation
  78. GRB 060708: PROMPT Optical Limits
  79. GRB 060707: OA fading and redshift
  80. GCN 060708: Swift-UVOT Observations
  81. GCN 060707: Swift-UVOT observations
  82. GRB 060707: Swift-XRT refined analysis
  83. GRB060707 possible optical confirmation
  84. GRB 060707: BOOTES-IR optical afterglow candidate
  85. GRB 060707: BOOTES-IR optical observation
  86. GRB 060614: Detection of a Possible, Late-Time Rebrightening
  87. GRB060614: Detection of the host galaxy but no supernova emission
  88. GRB060614: Optical observations
  89. GRB060512: near IR observations
  90. GRB060526: optical observations
  91. GRB060605: optical observation
  92. The Unusually Long-Lived Afterglow of GRB 060614
  93. GRB 060614: optical observations
  94. GRB 060605, optical observations
  95. GRB 060614, SMARTS optical/IR afterglow observation
  96. GRB 060614: Swift/UVOT Observations
  97. GRB 060604, optical observations
  98. GRB 060614: Swift detection of a burst with a bright optical and X-ray counterpart
  99. GRB 060607: RTT150 optical observations
  100. GRB 070706B: Watcher upper limit

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