Improved Electrical Properties of n-Type SiGe Alloys

Scoville, A. N.; Bajgar, C.; Vandersande, Jan W.; Fleurial, Jean‐Pierre

doi:10.4271/929419

Cited by 2 publications

(2 citation statements)

References 2 publications

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“…In addition, the luminosity and space density of ULIRGs are similar to those of QSOs. Moreover, the luminosity function of IRAS galaxies is of a double power-low type, and thus differs from that of the normal galaxies that show exponential rollover and is rather similar to that of QSOs or starbursts (Scoville 1992). Thus, it has been suggested that ULIRGs are powered by the heavily obscured QSOs (e.g., Sanders et al 1988) or the starbursts (Joseph & Wright 1985).…”

Section: Introductionmentioning

confidence: 94%

Type I Ultraluminous Infrared Galaxies: Transition Stage from ULIRGs to QSOs

Kawakatu

Anabuki

Nagao

et al. 2006

ApJ

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We examine whether the ultraluminous infrared galaxies that contain a type I Seyfert nucleus (a type I ULIRG) are in the transition stage from ULIRGs to quasi-stellar objects (QSOs). To inspect this issue, we compare the black hole (BH) mass, the bulge luminosity and the far infrared luminosity among type I ULIRGs, QSOs and elliptical galaxies. As a result, we find the following results; (1) The type I ULIRGs have systematically smaller BH masses in spite of the comparable bulge luminosity relative to QSOs and elliptical galaxies. (2) The far-infrared luminosity of most type I ULIRGs is larger than the Eddington luminosity. We show that above results do not change significantly for 3 type I ULIRGs that we can estimate the visual extinction from the column density. Also, for all 8 type I ULIRGs, we investigate the effect of uncertainties of BH mass measurments and our sample bias, so that it turns out that our results do not alter even if we consider above two effects. In addition, Anabuki (2004) revealed that their X-ray properties are similar to those of the narrow line Seyfert 1 galaxies. These would indicate that active galactic nuclei (AGNs) with a high mass accretion rate exist in the type I ULIRGs. Based on all of these findings, we conclude that it would be a natural interpretation that type I ULIRGs are the early phase of BH growth, namely the missing link between ULIRGs and QSOs. Moreover, by comparing our results with a theoretical model of a coevolution scenario of a QSO BH and a galactic bulge, we show clearly that this explanation would be valid.

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Section: Introductionmentioning

confidence: 94%

Type I Ultraluminous Infrared Galaxies: Transition Stage from ULIRGs to QSOs

Kawakatu

Anabuki

Nagao

et al. 2006

ApJ

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“…Despite numerous studies of molecular gas in the Milky Way and galaxies (Scoville & Sanders 1987;Blitz et al 2007), the processes affecting evolution of GMCs have remained poorly understood. In fact, uncertainty remains as to whether GMCs are stable structures that survive over a galactic rotation period (> 10 8 yrs; Scoville & Hersh 1979;Scoville & Wilson 2004) or are transient structures, destroyed immediately after formation by violent feedback from young stars [a few ×10 7 yrs; Blitz & Shu 1980;Elmegreen 2007, or even shorter ∼ 10 6 yrs; Elmegreen 2000;Hartmann, Ballesteros-Paredes & Bergin 2001].…”

Section: Introductionmentioning

confidence: 99%

Dynamically Driven Evolution of the Interstellar Medium in M51

Koda

Scoville

Sawada

et al. 2009

ApJ

180

236

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Massive star formation occurs in Giant Molecular Clouds (GMCs); an understanding of the evolution of GMCs is a prerequisite to develop theories of star formation and galaxy evolution. We report the highest-fidelity observations of the grand-design spiral galaxy M51 in carbon monoxide (CO) emission, revealing the evolution of GMCs vis-a-vis the large-scale galactic structure and dynamics. The most massive GMCs (Giant Molecular Associations -GMAs) are first assembled and then broken up as the gas flow through the spiral arms. The GMAs and their H 2 molecules are not fully dissociated into atomic gas as predicted in stellar feedback scenarios, but are fragmented into smaller GMCs upon leaving the spiral arms. The remnants of GMAs are detected as the chains of GMCs that emerge from the spiral arms into interarm regions. The kinematic shear within the spiral arms is sufficient to unbind the GMAs against self-gravity. We conclude that the evolution of GMCs is driven by largescale galactic dynamics -their coagulation into GMAs is due to spiral arm streaming motions upon entering the arms, followed by fragmentation due to shear as they leave the arms on the downstream side. In M51, the majority of the gas remains molecular from arm entry through the inter-arm region and into the next spiral arm passage.

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Improved Electrical Properties of n-Type SiGe Alloys

Cited by 2 publications

References 2 publications

Type I Ultraluminous Infrared Galaxies: Transition Stage from ULIRGs to QSOs

Type I Ultraluminous Infrared Galaxies: Transition Stage from ULIRGs to QSOs

Dynamically Driven Evolution of the Interstellar Medium in M51

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