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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"

15684 results found.

  1. GRB060904b optical detections (delayed report due to internet outage)
  2. GRB 060906: optical observation
  3. GRB 060906: Early RAPTOR optical limits
  4. GRB 060906: Swift/XRT Refined Analysis
  5. GRB 060906: Swift-UVOT observations
  6. VLT redshift of GRB 060906
  7. GRB 060906: KAIT observations
  8. GRB 060906: Confirmation of P60 Optical Afterglow
  9. GRB 060906 (?): P60 Optical Afterglow Candidate
  10. GRB060904b, optical observations
  11. GRB 060904b: SMARTS optical/IR afterglow observations
  12. GRB 060904B: RTT150 optical observations
  13. GRB060904A: Swift/UVOT optical observations
  14. GRB060904b: Optical observations with Swift/UVOT
  15. GRB 060904B: VLT redshift
  16. GRB 060904B: Optical observations at Crni Vrh
  17. GRB060904B: Watcher observations
  18. GRB 060904B BOOTES-IR and 1.5m OSN observations
  19. GRB 060904B: TAROT optical counterpart observations
  20. GRB 060904: TAROT optical observations
  21. GRB 060904B: Swift detection of a burst with optical counterpart
  22. GRB 060904B: ROTSE-III Detection of Optical Counterpart
  23. GRB060901: Optical observations
  24. GRB 060901: SMARTS optical/IR observations update
  25. GRB 060901: SMARTS optical/IR observations
  26. GRB 060605, observations using an Integral Field Unit
  27. GRB 060826(?): Swift detection of a possible burst
  28. GRB060825: Liverpool Telescope optical observations
  29. GRB 060825: TNG optical observations
  30. GRB 060825: TAROT optical observations
  31. GRB060825: BOOTES-IR optical observations
  32. GRB 060729, SMARTS optical/IR observations
  33. GRB060814: Break in the XRT light curve
  34. GRB060813: Break in the XRT light curve
  35. GRB060805B: optical observations
  36. GRB060814: Swift/UVOT upper limits
  37. GRB 060814: VLT optical limits
  38. GRB 060814: TAROT optical observations
  39. GRB060813: Swift/UVOT upper limits
  40. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  41. GRB060807: Possible Highly Significant X-ray Emission Lines
  42. GRB060714: optical observations
  43. GRB 060729: An update on the Swift XRT and UVOT observations
  44. GRB060717: optical observations
  45. GRB060807: Optical limiting magnitudes
  46. GRB 060805B: optical observation at Sierra Nevada
  47. GRB 060805B: XRT Team Analysis
  48. GRB 060807: UVOT Upper limits
  49. GRB 060807: afterglow confirmation
  50. GRB 060807: K- and R-band observations
  51. GRB060807: optical afterglow candidate
  52. GRB060807: optical upper limit in white light
  53. GRB 060805B: X-ray Afterglow Detection, Spectral/Spatial/Temporal Properties
  54. GRB 060805B: Swift/UVOT Upper Limits
  55. GRB 060807, optical observation
  56. GRB 060807: optical limit
  57. GRB 060805: optical upper limit in R
  58. GRB 060805: Swift/UVOT Upper Limits
  59. GRB 060804: Swift UVOT observations
  60. GRB 060801: no variability of optical sources
  61. GRB 060801: WSRT Radio Observations
  62. GRB 060801: XRT/SDSS Frame Offset and Refined XRT Position
  63. GRB 051109B: Bright spiral host galaxy at low redshift
  64. GRB 060801: optical observations at FORS2/VLT
  65. GRB060801: Swift/UVOT Upper Limits
  66. GRB 060801: optical observations at Hanle and Calar Alto
  67. GRB060801: optical upper limit in R
  68. GRB 060801, optical observation
  69. GRB 060801: Kanazawa Optical Observation
  70. GRB060729: ROTSE-III Observations of the Slow Optical Decay
  71. GRB 060719: TORTOREM optical upper limits
  72. GRB 060729: Swift/UVOT Detections
  73. GRB 060729: Swift/UVOT Observations
  74. GRB 060729: ROTSE-III Detection of Optical Counterpart
  75. GRB 060729: Swift detection of a burst with an UVOT optical counterpart
  76. GRB 060728: Refined analysis of the Swift-BAT burst
  77. GRB 060728, SMARTS optical/IR observations
  78. GRB 060218 (SN 2006aj): IR afterglow detection six months after the
  79. GRB 060714: Swift/UVOT Observations
  80. GRB060719: prompt NIR observations with REM
  81. GRB 060714: NOT observations
  82. GRB 060719: near-infrared afterglow
  83. GRB 060719: optical limit by Pi-of-the-Sky
  84. GRB 060719: prompt PROMPT observations
  85. GRB 060719: Continued LCO optical observations
  86. GRB 060719: LCO optical observations
  87. GRB 060714: OA fading and a possible host detection
  88. GRB060714: optical observations
  89. GRB 060717: NOT observations
  90. GRB 060717 optical upper limit
  91. GRB 060717, optical observation
  92. GRB060714: optical observations
  93. GRB 060714, SMARTS optical/IR afterglow observation
  94. GRB 060714: Swift XRT refined analysis
  95. GRB 060714: OA redshift
  96. GRB 060708: VLT spectroscopy
  97. GRB060708: MARGE low resolution spectrum observations
  98. GRB060714: optical observations
  99. Correction to Circular 5314: Circular refers to GRB 060714
  100. GRB060707 possible optical confirmation

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