EVOLUTION OF THE QUASAR POPULATION AT HIGH REDSHIFT
... First I would like to thank my advisor Xiaohui Fan for his guidance, encouragement,
and his friendship. He always inspires me to develop independent thinking and
research skills, and to collaborate with others in different fields. Without his support,
I could not have done my doctoral work.
I am gra ...
The Observer`s Guide to the Gamma-Ray Burst
... The luminosity, energetics and shape of the γ-ray pulse of a given GRB can reveal clues to
the origin of its high-energy emission, and thus its emission process. Of particular importance is
whether the γ-rays emitted by llGRBs arise from the same mechanism as high-luminosity GRBs
(i.e. from a jet), ...
the mass distribution and lifetime of prestellar cores in perseus
... Ophiuchus. In a companion paper to this work (M. L. Enoch
et al. 2008, in preparation), we use the comparison of 1.1 mm
and Spitzer data to study the properties of embedded protostars.
In particular, we examine the bolometric temperatures and luminosities of Class 0 and Class I protostars in Perseus ...
Galaxy And Mass Assembly (GAMA): Gas Fuelling of Spiral Galaxies
... We quantify the effect of the galaxy group environment (for group masses of 1012.5 to 1014.0 M ) on
the current star formation rate (SFR) of a pure, morphologically-selected, sample of disk-dominated
(i.e. late-type spiral) galaxies with redshift ≤ 0.13. The sample embraces a full representation of ...
Herschel/PACS spectroscopy of NGC 4418 and Arp 220: H2O
... the comparison indicates that both sources are at far-IR wavelengths point-sources compared with the PACS 9 × 9 spatial
resolution (∼1.3 × 1.3 kpc2 for NGC 4418 and ∼3.1 × 3.1 kpc2
for Arp 220).
The continua of both sources are shown in Fig. 1, including the Spitzer IRS spectra (Spoon et al. 200 ...
β Relation for Local Galaxies
... a much lower ratio of the b-parameter compared to starburst galaxies. However, the results of
Boquien et al. (2009, 2012), and Siebert et al. (2005) do not support the birthrate parameter
result; instead, they suggest that the offset may merely be a result of the difference in dust
geometry between ...
Watson et al. 2007a - Department of Physics and Astronomy
... Solar- and later-type young stars, and test the standard models of dust processing
which result in the conversion of originally amorphous dust into minerals. We find
strong evidence of evolution of the dust crystalline mass fraction in parallel with that of
the structure of the disks, in the sense t ...
Galaxy Formation and Evolution.
... F R A N K VA N D E N B O S C H is Assistant Professor at Yale University, and is known for his
studies of the formation, dynamics, and clustering of galaxies.
S I M O N W H I T E is Director at the Max Planck Institute for Astrophysics in Garching. He is
one of the originators of the modern theory o ...
Direct Evidence for Termination of Obscured Star Formation by
... local to the SMBH can (3) heat gas in the ISM, and/or
(4) drive gas out of the galaxy via kinetic pressure.
Most discussions of AGN feedback condense the four
feedback mechanisms described above into two simplified paradigms; ‘quasar’ mode feedback and ‘radio’ mode
feedback. Quasar mode feedback ass ...
submillimeter observations of giant molecular clouds in the large
... regions N158C, N159, and N160 with a few prominent CO clouds
in the J ¼ 2Y1 and J ¼ 3Y2 transitions of CO. They find that
the kinetic temperatures are 10Y80 K and the highest temperature is toward 30 Dor. The smallest beam size and grid spacing
are 1500 and 1100 , respectively, in the J ¼ 3Y2 emissi ...
University of Groningen Late-type spiral galaxies Ganda, Katia
... 2005) mainly refers to the emission-line properties, to the characteristics of the HII regions
or to the nature of the innermost component. In particular, no study has addressed yet in
a systematic way the stellar populations of late-type spiral galaxies with a two-dimensional
coverage. Existing stu ...
... The flux-limited sub-mm selection ensures a relatively
homogenous sample of the most intensely starforming
dust obscured galaxies at z & 3: Due to the negative kcorrection, the sub-mm flux detection limit corresponds
roughly to a cut in SFR over the considered redshift
range. Note that while a fract ...
Modeling Spatially and Spectrally Resolved Observations to
... This thesis owes much to the support of my officemate, Zach Berta, for five years of
advice on life, computers, and astronomy. I thank Diego Muñoz, Robert Harris, Ragnhild
Lunnan, and Sarah Rugheimer for countless snack and coffee breaks; Wen-fai Fong and
Nick Stone for leading camping trips and t ...
Constraints on the physical properties and chemical evolution of star
... constrain the physical properties and chemical enrichment of the gas in galaxies at all cosmic epochs. This is important, because galaxies are being detected at always higher redshift
and upcoming observations with large telescopes, such as the James Webb Space Telescope,
will gather high-quality sp ...
The 3-D shaping of NGC 6741: A massive, fast
... surrounded by a sharp low-excitation skin (the ionization front), and embedded in a spherical (radius 0.080 pc), almostneutral, high-density (n(H I) 7 × 103 atoms cm−3 ) halo containing a large fraction of the nebular mass (Mhalo ≥ 0.20 M ).
The kinematics, physical conditions and ionic structu ...
Standard solar model
The standard solar model (SSM) is a mathematical treatment of the Sun as a spherical ball of gas (in varying states of ionisation, with the hydrogen in the deep interior being a completely ionised plasma). This model, technically the spherically symmetric quasi-static model of a star, has stellar structure described by several differential equations derived from basic physical principles. The model is constrained by boundary conditions, namely the luminosity, radius, age and composition of the Sun, which are well determined. The age of the Sun cannot be measured directly; one way to estimate it is from the age of the oldest meteorites, and models of the evolution of the Solar System. The composition in the photosphere of the modern-day Sun, by mass, is 74.9% hydrogen and 23.8% helium. All heavier elements, called metals in astronomy, account for less than 2 percent of the mass. The SSM is used to test the validity of stellar evolution theory. In fact, the only way to determine the two free parameters of the stellar evolution model, the helium abundance and the mixing length parameter (used to model convection in the Sun), are to adjust the SSM to ""fit"" the observed Sun.