Lyman-alpha imaging of starburst galaxies in the local universe and beyond Matthew Hayes
... we do understand comes from observations of the stars; by observing the radiation they produce directly, by observing reprocessed stellar energy, or by observing the violent phenomena in the final stages of stellar evolution. All but a very small fraction of stars in the universe reside in the confi ...
... we do understand comes from observations of the stars; by observing the radiation they produce directly, by observing reprocessed stellar energy, or by observing the violent phenomena in the final stages of stellar evolution. All but a very small fraction of stars in the universe reside in the confi ...
relative age difference between the metal
... (2002 April and 2003 May) as the observations of the GC M92 (NGC 6341) reported by Cho and Lee using the same instrumental setup. The data for M53 is reduced using the same method as used for M92 by Cho and Lee, including preprocessing, point-spread function fitting photometry, and standardization e ...
... (2002 April and 2003 May) as the observations of the GC M92 (NGC 6341) reported by Cho and Lee using the same instrumental setup. The data for M53 is reduced using the same method as used for M92 by Cho and Lee, including preprocessing, point-spread function fitting photometry, and standardization e ...
https://tel.archives-ouvertes.fr/file/index/docid/1058049/filename/HOU_XIAN_2013.pdf
... This is a milestone in my life, even though there is still definitely a long way to go in the ultimate pursuit of science. I owe my deep acknowledgements to all who have made me who I am today. First of all, I’m extremely grateful to David Smith, my thesis supervisor, for having accepted me to be a ...
... This is a milestone in my life, even though there is still definitely a long way to go in the ultimate pursuit of science. I owe my deep acknowledgements to all who have made me who I am today. First of all, I’m extremely grateful to David Smith, my thesis supervisor, for having accepted me to be a ...
Lya escape from z~ 0.03 star-forming galaxies: the dominant role of
... their escape from galaxies. These processes can only be observed in detail out to a few ×100 Mpc. Past nearby (z < 0.3) spectroscopic studies are based on small samples and/or kinematically unresolved data. Taking advantage of the high sensitivity of HST ’s COS, we observed the Lyα lines of 20 Hα-se ...
... their escape from galaxies. These processes can only be observed in detail out to a few ×100 Mpc. Past nearby (z < 0.3) spectroscopic studies are based on small samples and/or kinematically unresolved data. Taking advantage of the high sensitivity of HST ’s COS, we observed the Lyα lines of 20 Hα-se ...
STARLAB
... introduced in Grade One section but add the stories of Leo the Lion, Auriga the Charioteer, Lepus the Hare, Draco, and the Pleiades. Look at these constellations using the Constellation Cylinder. Hand out arrow pointers and show their locations. Look at the Starfield Cylinder and try to locate the s ...
... introduced in Grade One section but add the stories of Leo the Lion, Auriga the Charioteer, Lepus the Hare, Draco, and the Pleiades. Look at these constellations using the Constellation Cylinder. Hand out arrow pointers and show their locations. Look at the Starfield Cylinder and try to locate the s ...
The effect of stellar limb darkening values on the accuracy of the
... Some modellers fix the limb darkening coefficients according to these or other tables when they fit a transit curve. As is clear from the aforementioned discrepancies, in some temperature regions this is not a good strategy because the values of the limb darkening coefficients are not consistent and ...
... Some modellers fix the limb darkening coefficients according to these or other tables when they fit a transit curve. As is clear from the aforementioned discrepancies, in some temperature regions this is not a good strategy because the values of the limb darkening coefficients are not consistent and ...
The Physical Origins of The Morphology
... monly invoked. In any case, gas-deficient spiral galaxies in clusters do exist (e.g., Giovanelli & Haynes 1985), which indicates that gas stripping occurs. Eventually, in all these scenarios, gas stripping removes the fuel for star formation, presumably producing a quiescent galaxy which is similar ...
... monly invoked. In any case, gas-deficient spiral galaxies in clusters do exist (e.g., Giovanelli & Haynes 1985), which indicates that gas stripping occurs. Eventually, in all these scenarios, gas stripping removes the fuel for star formation, presumably producing a quiescent galaxy which is similar ...
The empirical grounds of SN
... different angles. GRB 030329/SN 2003dh may be viewed ~ pole-on, GRB 980425/SN 1998bw considerably off-axis (15-30°, Maeda et al. 2005). GRB 031203/SN 2003lw may lie in between (Ramirez-Ruiz et al. 2005) In this scenario the g-properties are a strong function of the angle (Eg 4 ) whereas the opti ...
... different angles. GRB 030329/SN 2003dh may be viewed ~ pole-on, GRB 980425/SN 1998bw considerably off-axis (15-30°, Maeda et al. 2005). GRB 031203/SN 2003lw may lie in between (Ramirez-Ruiz et al. 2005) In this scenario the g-properties are a strong function of the angle (Eg 4 ) whereas the opti ...
Galaxy And Mass Assembly (GAMA): Gas Fuelling of Spiral Galaxies
... density of gas in the disk increases as gas from the IHM continues to be accreted, until it becomes sufficient for the formation of dense, self-gravitating clouds which rapidly collapse to form stars, which then trace the disk as a visible galaxy. The rotationally supported gas in the disk therefore ...
... density of gas in the disk increases as gas from the IHM continues to be accreted, until it becomes sufficient for the formation of dense, self-gravitating clouds which rapidly collapse to form stars, which then trace the disk as a visible galaxy. The rotationally supported gas in the disk therefore ...
The Observer`s Guide to the Gamma-Ray Burst
... long-duration (and their various sub-classes) gamma-ray bursts (GRBs) and their accompanying supernovae (SNe). The analysis presented here is from the point of view of an observer, with much of the emphasis placed on how observations, and the modelling of observations, have constrained what we known ...
... long-duration (and their various sub-classes) gamma-ray bursts (GRBs) and their accompanying supernovae (SNe). The analysis presented here is from the point of view of an observer, with much of the emphasis placed on how observations, and the modelling of observations, have constrained what we known ...
Dust attenuation up to z ≃ 2 in the AKARI North Ecliptic Pole Deep
... selected using different criteria will give us a global picture of the attenuation at work in star-forming galaxies and its evolution with redshift. Methods. We selected galaxies in the mid-IR from the deep survey of the North Ecliptic Field performed by the AKARI satellite. Using multiple filters o ...
... selected using different criteria will give us a global picture of the attenuation at work in star-forming galaxies and its evolution with redshift. Methods. We selected galaxies in the mid-IR from the deep survey of the North Ecliptic Field performed by the AKARI satellite. Using multiple filters o ...
Properties and nature of Be stars: 27. Orbital and recent long
... with a sampling rate of 7 ms during a lunar occultation on 1987 March 6. They detected an asymmetry of the envelope in agreement with the observed long-term V/R changes. They speculated that the speckle-interferometric component could have an eccentric orbit and that the recurrent shell phases could ...
... with a sampling rate of 7 ms during a lunar occultation on 1987 March 6. They detected an asymmetry of the envelope in agreement with the observed long-term V/R changes. They speculated that the speckle-interferometric component could have an eccentric orbit and that the recurrent shell phases could ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.