Lyman-alpha imaging of starburst galaxies in the local universe and beyond Matthew Hayes
... The universe is a large and poorly understood entity. A great deal of what 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. ...
... The universe is a large and poorly understood entity. A great deal of what 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. ...
arXiv:astro-ph/0702414v1 15 Feb 2007
... this, the sky was extracted from all slits and was divided by the sky in those slits, which had almost the same position as the corresponding slits used in the standard star calibration exposures. In total, 43 objects have been reduced, and six objects were included in both setups. The majority of t ...
... this, the sky was extracted from all slits and was divided by the sky in those slits, which had almost the same position as the corresponding slits used in the standard star calibration exposures. In total, 43 objects have been reduced, and six objects were included in both setups. The majority of t ...
this article
... formation rates. While the majority of Sa–Sab galaxies in our sample are forming stars at a modest rate, a significant fraction (29%) exhibit star formation rates greater than 1 M yr1, rivaling the most prolifically star-forming latetype spirals. A similar diversity is apparent in the star format ...
... formation rates. While the majority of Sa–Sab galaxies in our sample are forming stars at a modest rate, a significant fraction (29%) exhibit star formation rates greater than 1 M yr1, rivaling the most prolifically star-forming latetype spirals. A similar diversity is apparent in the star format ...
H-alpha Imaging of Early-type (Sa
... selected by Kennicutt (1983) and Kennicutt (1994) is small in number and is biased towards galaxies with low values of L(FIR)/L(B) (Devereux & Hameed 1997; Usui et al. 1998). We are, therefore, conducting an Hα imaging survey of all known nearby early-type spiral galaxies in order to better understa ...
... selected by Kennicutt (1983) and Kennicutt (1994) is small in number and is biased towards galaxies with low values of L(FIR)/L(B) (Devereux & Hameed 1997; Usui et al. 1998). We are, therefore, conducting an Hα imaging survey of all known nearby early-type spiral galaxies in order to better understa ...
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 ...
- Mineralogical Society of America
... in the early Solar System, such as heating and collision, and were eventually incorporated into the parent bodies of primitive meteorites. Presolar grains are identified by their having isotopic compositions that can be drastically different from terrestrial, and from one another, depending on their ...
... in the early Solar System, such as heating and collision, and were eventually incorporated into the parent bodies of primitive meteorites. Presolar grains are identified by their having isotopic compositions that can be drastically different from terrestrial, and from one another, depending on their ...
Link - Max-Planck-Institut für Astronomie
... In the last twenty years, the topic of episodic accretion has gained significant interest in the star formation community. It is now viewed as a common, though still poorly understood, phenomenon in low-mass star formation. The FU Orionis objects (FUors) are long-studied examples of this phenomenon. ...
... In the last twenty years, the topic of episodic accretion has gained significant interest in the star formation community. It is now viewed as a common, though still poorly understood, phenomenon in low-mass star formation. The FU Orionis objects (FUors) are long-studied examples of this phenomenon. ...
Modeling Spatially and Spectrally Resolved Observations to
... a model for the rate of merger-induced post-starburst galaxies selected from optical spectra, resolving tension between their observed rarity and merger rates from other iii ...
... a model for the rate of merger-induced post-starburst galaxies selected from optical spectra, resolving tension between their observed rarity and merger rates from other iii ...
arXiv:astro-ph/0703091v1 5 Mar 2007
... 2006). For our present paper we have chosen to use the “quenched” mass formula ETFSI-Q for the following reasons. In principle, a weakening of the strong N=82 shell below 132 Sn had already been suggested by Kratz et al. (1993) from, at that time, scarce experimental indications in the phase transit ...
... 2006). For our present paper we have chosen to use the “quenched” mass formula ETFSI-Q for the following reasons. In principle, a weakening of the strong N=82 shell below 132 Sn had already been suggested by Kratz et al. (1993) from, at that time, scarce experimental indications in the phase transit ...
HI in Early-type Galaxies
... for star formation to occur on a reasonable large scale, and indeed star formation is observed in the centres of these galaxies. Outside the centre, the surface densities of the HI are below 1 M¯ pc−2 and perhaps only sporadic star formation could occur. In contrast, the surface densities in the mor ...
... for star formation to occur on a reasonable large scale, and indeed star formation is observed in the centres of these galaxies. Outside the centre, the surface densities of the HI are below 1 M¯ pc−2 and perhaps only sporadic star formation could occur. In contrast, the surface densities in the mor ...
Post-Common-Envelope Binaries from the Sloan Digital Sky Survey
... I am greatly indebted to Prof. Tom Marsh for clarifying all kind of data reduction problems, and specially I am deeply thankful for his patience at the beginning of my PhD. I also thank him for providing his software. I thank Dr. Pablo Rodrı́guez-Gil for his help in my first individual observations, ...
... I am greatly indebted to Prof. Tom Marsh for clarifying all kind of data reduction problems, and specially I am deeply thankful for his patience at the beginning of my PhD. I also thank him for providing his software. I thank Dr. Pablo Rodrı́guez-Gil for his help in my first individual observations, ...
Lya escape from z~ 0.03 star-forming galaxies: the dominant role of
... radiation from OB stars. This helps in the interpretation of the observed Lyα properties because we do not need to worry about non-stellar ionizing sources such as active galactic nuclei (AGNs), which account for some of the high Lyα EWs at z > 2 (Charlot & Fall 1993; Zheng et al. 2010), and low-ion ...
... radiation from OB stars. This helps in the interpretation of the observed Lyα properties because we do not need to worry about non-stellar ionizing sources such as active galactic nuclei (AGNs), which account for some of the high Lyα EWs at z > 2 (Charlot & Fall 1993; Zheng et al. 2010), and low-ion ...
Galaxies in the Universe: An Introduction, Second Edition
... are based on meters and kilograms. In other cases, we have assumed that readers will be able to convert fairly easily between the two systems with the aid of Appendix A. Astronomers still disagree significantly on the distance scale of the Universe, parametrized by the Hubble constant H0 . We often i ...
... are based on meters and kilograms. In other cases, we have assumed that readers will be able to convert fairly easily between the two systems with the aid of Appendix A. Astronomers still disagree significantly on the distance scale of the Universe, parametrized by the Hubble constant H0 . We often i ...
Giant Low Surface Brightness Galaxies
... Several studies have tried to understand the lack of star formation in LSB galaxies. In general the presence of copious amounts of neutral hydrogen gas in galaxies indicates that they have the capacity to form stars through cloud collapse and star formation. But although LSB galaxies are gas-rich, t ...
... Several studies have tried to understand the lack of star formation in LSB galaxies. In general the presence of copious amounts of neutral hydrogen gas in galaxies indicates that they have the capacity to form stars through cloud collapse and star formation. But although LSB galaxies are gas-rich, t ...
Radiation-driven wind models of massive stars
... al. (1992) for an overview. Moreover, as massive stars are hot, with effective temperatures in the range of about 10 000 - 50 000 K, they emit a large amount of UV photons. This radiation ionizes the surrounding nebula and heats the associated H II region. As massive stars are mostly seen grouped in ...
... al. (1992) for an overview. Moreover, as massive stars are hot, with effective temperatures in the range of about 10 000 - 50 000 K, they emit a large amount of UV photons. This radiation ionizes the surrounding nebula and heats the associated H II region. As massive stars are mostly seen grouped in ...
Neutron Stars and the Determination of the Dense Matter Equation
... A physical understanding of the behaviour of cold ultra-dense matter – at and above nuclear density – can only be achieved by the study of neutron stars. The surface thermal emission from neutron stars in quiescent low-mass X-ray binaries (qLMXBs) inside globular clusters has proven useful for that ...
... A physical understanding of the behaviour of cold ultra-dense matter – at and above nuclear density – can only be achieved by the study of neutron stars. The surface thermal emission from neutron stars in quiescent low-mass X-ray binaries (qLMXBs) inside globular clusters has proven useful for that ...
From Filamentary Networks to Dense Cores in Molecular Clouds
... 2.1 Evidence of interstellar filaments prior to Herschel The presence of parsec-scale filamentary structures in nearby interstellar clouds and their potential importance for star formation have been pointed out by many authors for more than three decades. For example, Schneider and Elmegreen (1979) ...
... 2.1 Evidence of interstellar filaments prior to Herschel The presence of parsec-scale filamentary structures in nearby interstellar clouds and their potential importance for star formation have been pointed out by many authors for more than three decades. For example, Schneider and Elmegreen (1979) ...
Formation and evolution of giant molecular clouds in a barred spiral
... Understanding where and how gas is converted into stars in a galaxy is important for understanding a galaxy’s formation and evolution through each epoch of the universe. Which physical processes control the star formation in a galaxy is heavily debated. We are now at a stage where it is possible to ...
... Understanding where and how gas is converted into stars in a galaxy is important for understanding a galaxy’s formation and evolution through each epoch of the universe. Which physical processes control the star formation in a galaxy is heavily debated. We are now at a stage where it is possible to ...
Properties and nature of Be stars: 27. Orbital and recent long
... that the shell RVs vary with periods of 136.0 and 106.7 days. Katahira et al. (1996a,b) analyzed shell RVs from the two consecutive shell phases separated some 34 years, using published as well as new RVs and concluded that BU Tau is a spectroscopic binary with an orbital period of 218.d 0, semi-amp ...
... that the shell RVs vary with periods of 136.0 and 106.7 days. Katahira et al. (1996a,b) analyzed shell RVs from the two consecutive shell phases separated some 34 years, using published as well as new RVs and concluded that BU Tau is a spectroscopic binary with an orbital period of 218.d 0, semi-amp ...
Infrared identification of high-mass X
... IBIS/ISGRI detector onboard the INTEGRAL observatory. Furthermore, they were all observed with other X-ray facilities to provide an accurate localization, which allowed us to determine the optical/NIR counterpart. The sample of 15 sources is given in Table 1. We present below our results on each sou ...
... IBIS/ISGRI detector onboard the INTEGRAL observatory. Furthermore, they were all observed with other X-ray facilities to provide an accurate localization, which allowed us to determine the optical/NIR counterpart. The sample of 15 sources is given in Table 1. We present below our results on each sou ...
White dwarfs, black holes and neutron stars in close binaries
... hite dwarfs, neutron stars and black holes are remnants of stars that have ended their ‘active’ life. A star is born when an interstellar gas cloud contracts and forms a sphere which in its centre has a temperature and pressure high enough to start hydrogen fusion. The star remains in this phase for ...
... hite dwarfs, neutron stars and black holes are remnants of stars that have ended their ‘active’ life. A star is born when an interstellar gas cloud contracts and forms a sphere which in its centre has a temperature and pressure high enough to start hydrogen fusion. The star remains in this phase for ...
Kuchnig_CW8 - Sciences et techniques
... planetary conjunction by ~0.1 cycle weak secondary minimum (and first harmonic) evidence of tidal distortion of star? ...
... planetary conjunction by ~0.1 cycle weak secondary minimum (and first harmonic) evidence of tidal distortion of star? ...
Systematic Study of Mass Loss in the Evolution of Massive Stars
... they are still not well known because of the large uncertainties involved in modeling the evolution of such stars. Because of their large mass, theses stars are rather rare objects: they seldom form and are short lived. Nevertheless, their characteristics (e.g. high luminosity, large mass loss rate, ...
... they are still not well known because of the large uncertainties involved in modeling the evolution of such stars. Because of their large mass, theses stars are rather rare objects: they seldom form and are short lived. Nevertheless, their characteristics (e.g. high luminosity, large mass loss rate, ...
Planetary nebula
A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding glowing shell of ionized gas ejected from old red giant stars late in their lives. The word ""nebula"" is Latin for mist or cloud and the term ""planetary nebula"" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.A mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, appearing as a bright coloured planetary nebula at several discrete visible wavelengths.Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances.In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms which produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.