مورد إلكتروني
Nuclear Structure of Quasars at 329 Megahertz
| العنوان: | Nuclear Structure of Quasars at 329 Megahertz |
|---|---|
| المؤلفون: | Simon, Richard Stanley |
| بيانات النشر: | 1983 |
| تفاصيل مُضافة: | Simon, Richard Stanley |
| نوع الوثيقة: | Electronic Resource |
| مستخلص: | In the four chapters in this thesis are presented studies of compact quasars using Very Long Baseline Interferometry at 329 MHz. The first chapter presents hybrid maps of two quasars, 3C147 and 3C286, made at 329 MHz from VLBI observations taken in 1975 with a three station interferometer. The observations presented in the first chapter were used to make the first detailed maps of compact radio structure at this frequency. Both objects consist of an unresolved core; an extended, asymmetric jet; and an even larger, completely resolved halo. For 3C147 it is possible to decompose the spectrum into individual component spectra; at 329 MHz the core of 3C147 is found to be strongly self-absorbed. For both sources the spectral index decreases monotonically from core to jet to halo. The second chapter presents further observations of quasars at 329 MHz. These observations were taken with a seven-station interferometer and were used to produce high dynamic range maps of the quasars 3C48, 3C147, 3C309.1, 3C380, and 3C454.3. These maps, made with the most extensive low-frequency VLBI observations to date, are the first reliable, high dynamic range maps at this frequency, and reveal extremely complex source structure in four of these sources. All five of the objects are seen to have asymmetric structure that can be interpreted in the "core-jet" picture of compact extragalactic radio sources. The jets observed in these objects are not straight, but bent; three of these quasars have bends in their structure greater than 90° on scales of 1 - 10 kpc. Chapter three deals with the analysis of the two maps of 3C147 presented in chapters 1 and 2. Comparison of those maps reveals that the core of 3C147 is a low-frequency variable radio source which has brightened by a factor of two in six years. In combination with X-ray observations this is used to demonstrate that bulk relativistic motion is taking place within the core and leads to the prediction that 3C147 is |
| مصطلحات الفهرس: | Thesis, NonPeerReviewed |
| URL: | CaltechETD:etd-09092008-093723 10.7907/zyfw-8c64 |
| الإتاحة: | Open access content. Open access content other |
| ملاحظة: | application/pdf English |
| أرقام أخرى: | CIT oai:thesis.library.caltech.edu:3409 https://thesis.library.caltech.edu/3409/1/Simon_rs_1983.pdfTest Simon, Richard Stanley (1983) Nuclear Structure of Quasars at 329 Megahertz. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/zyfw-8c64. https://resolver.caltech.edu/CaltechETD:etd-09092008-093723Test <https://resolver.caltech.edu/CaltechETD:etd-09092008-093723Test> 1013193480 |
| المصدر المساهم: | CALIFORNIA INST OF TECH From OAIster®, provided by the OCLC Cooperative. |
| رقم الانضمام: | edsoai.on1013193480 |
| قاعدة البيانات: | OAIster |
| الوصف غير متاح. |