Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- 9 ethyl guanine (1)
- AGN (1)
- Active Galactic Nuclei (1)
- Active galaxies (1)
- Astronomy (1)
-
- BLIP temperature (1)
- Barriers (1)
- Bicones (1)
- CHARA (1)
- Cosmological Evolution (1)
- DFT (1)
- DNA (1)
- Dark current (1)
- Detectivity (1)
- Diffraction (1)
- Dynamics (1)
- EIE (1)
- ENDOR (1)
- EPR (1)
- Emitters (1)
- FR II (1)
- Free carrier absorption (1)
- Gaussian (1)
- Heterojunction (1)
- High (1)
- Homojunction (1)
- IGM (1)
- Indium nitride (1)
- Infrared (1)
- Infrared detectors (1)
Articles 1 - 7 of 7
Full-Text Articles in Entire DC Network
The X-Ray Variability Of Seyfert Galaxies, Kevin Marshall
The X-Ray Variability Of Seyfert Galaxies, Kevin Marshall
Physics and Astronomy Dissertations
Strong and variable X-ray emission has long been known to be a universal property of active galaxies. However, despite years of study, the exact nature of the variability remains relatively unknown. We present here results of a multi-year monitoring campaign of a sample of Seyfert galaxies (3C 120, Mkn 509, 3C 390.3, and Akn 120), carried out using the Rossi X-ray Timing Explorer (RXTE). For Mkn 509, we also present results of optical monitoring. Mkn 509 shows a strong correlation between X-ray and optical variations, with the optical leading the X-ray by 25 days. We also investigate the rms-flux relationship …
Threshold Extension Of Gallium Arsenide/Aluminum Gallium Arsenide Terahertz Detectors And Switching In Heterostructures, Mohamed Buhary Rinzan
Threshold Extension Of Gallium Arsenide/Aluminum Gallium Arsenide Terahertz Detectors And Switching In Heterostructures, Mohamed Buhary Rinzan
Physics and Astronomy Dissertations
In this work, homojunction interfacial workfunction internal photoemission (HIWIP) detectors based on GaAs, and heterojunction interfacial workfunction internal photoemission (HEIWIP) detectors based mainly on the Gallium Arsenide/Aluminum Gallium Arsenide material system are presented. Design principles of HIWIP and HEIWIP detectors, such as free carrier absorption, photocarrier generation, photoemission, and responsivity, are discussed in detail. Results of p-type HIWIPs based on GaAs material are presented. Homojunction detectors based on p-type GaAs were found to limit their operating wavelength range. This is mainly due to band depletion arising through carrier transitions from the heavy/light hole bands to the split off band. Designing …
Modeling The Power Evolution Of Classical Double Radio Galaxies Over Cosmological Scales, Paramita Barai
Modeling The Power Evolution Of Classical Double Radio Galaxies Over Cosmological Scales, Paramita Barai
Physics and Astronomy Dissertations
During the quasar era (redshifts between 1 and 3) Radio Galaxies (RGs) have been claimed to have substantially influenced the growth and evolution of large scale structures in the universe. In this dissertation I test the robustness of these exciting claims. In order to probe the impacts in more detail, good theoretical models for such RG systems are required. With this motivation, I seek to develop an essentially analytical model for the evolution of Fanaroff-Riley Class II radio galaxies both as they age individually and as their numbers vary with cosmological epoch. To do so, I first compare three sophisticated …
Kinematics Of The Narrow-Line Regions In The Seyfert Galaxies Ngc 4151 And Ngc 1068, Varendra Das
Kinematics Of The Narrow-Line Regions In The Seyfert Galaxies Ngc 4151 And Ngc 1068, Varendra Das
Physics and Astronomy Dissertations
We present a study of high-resolution long-slit spectra of the Narrow-Line Regions (NLRs) of NGC 4151 (a Seyfert 1 galaxy) and NGC 1068 (a Seyfert 2 galaxy) obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). The spectra were retrieved from the Multimission Archive at Space Telescope (MAST) and were obtained from five and seven orbits of HST time resulting in five and seven parallel slit configurations at position angles of 52 degrees and 38 degrees for NGC 4151 and NGC 1068 respectively. The spectra have a spatial resolution of 0.2 arcsecond across and 0.1 …
High Pressure Chemical Vapor Deposition: A Novel Approach For The Growth Of Inn, Vincent Timothy Woods
High Pressure Chemical Vapor Deposition: A Novel Approach For The Growth Of Inn, Vincent Timothy Woods
Physics and Astronomy Dissertations
The development of next generation devices for high speed switching, high efficiency energy conversion, spintronic devices require the development of advanced material systems. While conventional group IV, group II-VI and group III-V based materials systems have served as a base material in many modern device structures, they posses fundamental materials properties that limit their suitability in next generation device structures. The group III-N material system is very promising for the development of advanced device structures. GaN is currently widely used in high efficiency lighting applications. However, the development of this material system has been limited to material systems with limited …
X-Irradiation Of Dna Components In The Solid State: Experimental And Computational Studies Of Stabilized Radicals In Guanine Derivatives, Nayana Kumudini Jayatilaka
X-Irradiation Of Dna Components In The Solid State: Experimental And Computational Studies Of Stabilized Radicals In Guanine Derivatives, Nayana Kumudini Jayatilaka
Physics and Astronomy Dissertations
Single crystals of sodium salt of guanosine dihydrate and 9 Ethyl Guanine were X-irradiated with the objective of identifying the radical products. Study with K-band EPR, ENDOR, and ENDOR-Induced EPR techniques indicated at least four radical species to appear in both crystals in the temperature range of 6K to room temperature. Three of these radicals (Radicals R1, R2, and R3) were present immediately after irradiation at 6K. Computational chemistry and EPR spectrum simulation methods were also used to assist in radical identifications. Radical R1, the product of net hydrogen addition to N7, and Radical R2, the product of electron loss …
A Prototype Visible To Near-Infrared Spectrograph For The Chara Array, A Long-Baseline Stellar Interferometer, Chad Elliott Ogden
A Prototype Visible To Near-Infrared Spectrograph For The Chara Array, A Long-Baseline Stellar Interferometer, Chad Elliott Ogden
Physics and Astronomy Dissertations
This work is a description of the Visible to near Infrared Spectrograph system for the CHARA array. The CHARA Array is a 6-telescope interferometer at the Mount Wilson Observatory in the mountains north of Pasadena, California. It combines the light from the 1-meter telescopes, and measures the visibility of the resulting interference fringes, which gives information about the source intensity distribution on the sky. The resolution of the instrument is proportional to the telescope separation, or baseline, divided by the wavelength. The VIS system operates in the 600-1000~nm wavelength range, a factor of 3 to 4 shorter than the standard …