ISOCAM 4 m imaging of the nuclear starburst in M83
... The observations, performed with the short wavelength channel of ISOCAM (Cesarsky et al., 1996), the camera onboard ISO (Kesslet et al., 1996) , took place at the very end of the Preliminary Verification (PV) phase of ISO in January 1996. The pixel field of view was 1.5 arcsec and the observations d ...
... The observations, performed with the short wavelength channel of ISOCAM (Cesarsky et al., 1996), the camera onboard ISO (Kesslet et al., 1996) , took place at the very end of the Preliminary Verification (PV) phase of ISO in January 1996. The pixel field of view was 1.5 arcsec and the observations d ...
San Pedro Mártir observations of microvariability in obscured quasars
... microvariability or intra-night variability, and this phenomenon has been monitored in samples of blazars and unobscured AGNs. Detecting optical microvariations in targets hidden by the obscuring torus is a challenging task because the region responsible for the variations is hidden from our sight. ...
... microvariability or intra-night variability, and this phenomenon has been monitored in samples of blazars and unobscured AGNs. Detecting optical microvariations in targets hidden by the obscuring torus is a challenging task because the region responsible for the variations is hidden from our sight. ...
April - Bristol Astronomical Society
... There are no Messier objects in Crater, however there are a number of galaxies from the NGC catalogue. NGC 3887 and NGC 3511 and NGC 3513 are the among the easier targets for amateur observers. NGC 3887 is an 11th magnitude barred spiral which lies within the bowl of Crater, to the northwest of zeta ...
... There are no Messier objects in Crater, however there are a number of galaxies from the NGC catalogue. NGC 3887 and NGC 3511 and NGC 3513 are the among the easier targets for amateur observers. NGC 3887 is an 11th magnitude barred spiral which lies within the bowl of Crater, to the northwest of zeta ...
PC3692: Physics of Stellar Structure (and Evolution)
... Milky Way is a typical disk galaxy (see Fig. 5). It consists a bulge and a thin disk. The disk is thin because it’s rotationally supported, like an audio CD. You also see black lanes in the galaxy, these are caused by dust obscuration. The diameter of our luminous Milky Way is about 30 kpc. The Sun ...
... Milky Way is a typical disk galaxy (see Fig. 5). It consists a bulge and a thin disk. The disk is thin because it’s rotationally supported, like an audio CD. You also see black lanes in the galaxy, these are caused by dust obscuration. The diameter of our luminous Milky Way is about 30 kpc. The Sun ...
Stars: Their Life and Afterlife
... they continue to shrink and glow faintly via KH contraction for many years. The Sun began its main-sequence life with a composition of • 74% hydrogen • 25% helium • ~1% heavier elements, or “metals” After ~4.6 billion years of burning hydrogen in its core, the Sun’s core is now ~65% helium, but enou ...
... they continue to shrink and glow faintly via KH contraction for many years. The Sun began its main-sequence life with a composition of • 74% hydrogen • 25% helium • ~1% heavier elements, or “metals” After ~4.6 billion years of burning hydrogen in its core, the Sun’s core is now ~65% helium, but enou ...
A forming disk at z 0.6: collapse of a gaseous disk or major merger
... spiral galaxies, our understanding of the formation of galactic disks still remains incomplete (Mayer et al. 2008). It has been suggested that a large fraction of local disks could have been rebuilt subsequent to a major merger since z = 1, owing to the remarkable coincidence of the evolution of the ...
... spiral galaxies, our understanding of the formation of galactic disks still remains incomplete (Mayer et al. 2008). It has been suggested that a large fraction of local disks could have been rebuilt subsequent to a major merger since z = 1, owing to the remarkable coincidence of the evolution of the ...
HR Diagram - TeacherWeb
... 2. Organize: Compare the colors of the following stars in the Star collection: Aldebaran, Betelgeuse, Sirius B, Spica, the Sun, and Vega. Drag the six stars to position them where you think they would fit on the Gizmo’s color scale. Click Sort stars on the Gizmo to check your placements. Mark the lo ...
... 2. Organize: Compare the colors of the following stars in the Star collection: Aldebaran, Betelgeuse, Sirius B, Spica, the Sun, and Vega. Drag the six stars to position them where you think they would fit on the Gizmo’s color scale. Click Sort stars on the Gizmo to check your placements. Mark the lo ...
3D Tour of the Universe Template
... regions, resulting in the formation of new young stars. As is common in these kinds of encounters, spiral structure was induced in the more massive galaxy. M51 is an easily found astronomical showpiece if the sky is dark, where suggestions of its spiral arms may be visible. As is also common with th ...
... regions, resulting in the formation of new young stars. As is common in these kinds of encounters, spiral structure was induced in the more massive galaxy. M51 is an easily found astronomical showpiece if the sky is dark, where suggestions of its spiral arms may be visible. As is also common with th ...
Formation of Globular Clusters: In and Out of Dwarf Galaxies
... The gas in early halos is not dense enough to form the observed globular clusters In addition, the cosmic time is less than 0.4 Gyr Moore et al. (2006) ...
... The gas in early halos is not dense enough to form the observed globular clusters In addition, the cosmic time is less than 0.4 Gyr Moore et al. (2006) ...
Devika kamath Institute of Astronomy, KU. Leuven, Belgium
... FIELDS OF THE POST-RGB STARS The number of stars we expect to see at any given time in the top 1 magnitude of the RGB is k = 2.77 x106 × birthrate tip-RGB Total number of stars observed in the top 1 magnitude of the RGB in the fields searched for post-RGB stars is 118927 (from SAGE) ...
... FIELDS OF THE POST-RGB STARS The number of stars we expect to see at any given time in the top 1 magnitude of the RGB is k = 2.77 x106 × birthrate tip-RGB Total number of stars observed in the top 1 magnitude of the RGB in the fields searched for post-RGB stars is 118927 (from SAGE) ...
THE MYSTERIOUS SICKLE OBJECT IN THE CARINA NEBULA: A
... Optical and near-infrared images of the Carina Nebula show a peculiar arc-shaped feature, which we call the ”Sickle”, next to the B-type star Trumpler 14 MJ 218. We use multi-wavelength observations to explore and constrain the nature and origin of the nebulosity. Using sub-mm data from APEX/LABOCA ...
... Optical and near-infrared images of the Carina Nebula show a peculiar arc-shaped feature, which we call the ”Sickle”, next to the B-type star Trumpler 14 MJ 218. We use multi-wavelength observations to explore and constrain the nature and origin of the nebulosity. Using sub-mm data from APEX/LABOCA ...
What is the minimum size of a star that will go supernova? A. Half
... Two forces battle for dominance within a star, gravity and radiation pressure. When the forces balance, the star is stable. If gravity is pulling inward towards the center, in what direction is radiation pressure acting? Answer: Pushing away from center Without radiation pressure, the gr ...
... Two forces battle for dominance within a star, gravity and radiation pressure. When the forces balance, the star is stable. If gravity is pulling inward towards the center, in what direction is radiation pressure acting? Answer: Pushing away from center Without radiation pressure, the gr ...
9 Measuring the properties of stars - Journigan-wiki
... Now, very quickly. Stars give off light that can be divided into spectra. The spectra indicate a star’s temperature. People have studied these spectra since the early 1800’s. One man, Henry Draper (1870’s) studied the classification of spectra. He died and his wife gave a fortune to Harvard to compi ...
... Now, very quickly. Stars give off light that can be divided into spectra. The spectra indicate a star’s temperature. People have studied these spectra since the early 1800’s. One man, Henry Draper (1870’s) studied the classification of spectra. He died and his wife gave a fortune to Harvard to compi ...
ES Chapter 30
... atmosphere. By comparing laboratory spectra of different gases with the dark lines in the solar spectrum, it is possible to identify the elements that make up the Sun’s outer layers. ...
... atmosphere. By comparing laboratory spectra of different gases with the dark lines in the solar spectrum, it is possible to identify the elements that make up the Sun’s outer layers. ...
Star Formation in Isolated Disk Galaxies. I. Models and
... isolated disk galaxies using a three-dimensional, smoothed particle hydrodynamics code. The model galaxies include a dark matter halo and a disk of stars and isothermal gas. Absorbing sink particles are used to directly measure the mass of gravitationally collapsing gas. They reach masses characteri ...
... isolated disk galaxies using a three-dimensional, smoothed particle hydrodynamics code. The model galaxies include a dark matter halo and a disk of stars and isothermal gas. Absorbing sink particles are used to directly measure the mass of gravitationally collapsing gas. They reach masses characteri ...
STELLAR FORMATION AND EVOLUTION
... region of young stars. As time goes on, stars change or evolve as the physics in their cores change. But for most of the lifetime of a star, it sits somewhere on the main sequence. We will begin by looking at what happens to most stars in the universe. These are the low mass stars. In space, there a ...
... region of young stars. As time goes on, stars change or evolve as the physics in their cores change. But for most of the lifetime of a star, it sits somewhere on the main sequence. We will begin by looking at what happens to most stars in the universe. These are the low mass stars. In space, there a ...
Milky Way inner halo reveals its age | COSMOS magazine
... halo region to date is 13.5 billion years old. White dwarf stars form when normal stars like the sun have burnt up all their fuel and lost their outer layers. The centre of the star becomes white hot before cooling over many years. “White dwarfs are remarkable objects,” said Kalirai. “They contain a ...
... halo region to date is 13.5 billion years old. White dwarf stars form when normal stars like the sun have burnt up all their fuel and lost their outer layers. The centre of the star becomes white hot before cooling over many years. “White dwarfs are remarkable objects,” said Kalirai. “They contain a ...
DISCOVERY OF HOT SUPERGIANT STARS NEAR THE GALACTIC
... of star formation in the Galactic center, where adverse environmental conditions such as turbulent molecular clouds, milligauss magnetic fields, and strong tidal forces may result in a relatively large Jeans mass for collapsing cloud cores (Morris 1993; Morris & Serabyn 1996). It is unknown if these ...
... of star formation in the Galactic center, where adverse environmental conditions such as turbulent molecular clouds, milligauss magnetic fields, and strong tidal forces may result in a relatively large Jeans mass for collapsing cloud cores (Morris 1993; Morris & Serabyn 1996). It is unknown if these ...
Lecture 12: Galaxy Evolution
... Dwarf galaxies • Dwarf galaxies are a crucial part of the galaxy evolution puzzle but we know very little about them. • Main theory (see later) proposes that galaxies built-up from smaller units through repeated merging. • Numerical simulations typically predict several thousand dark matter haloe ...
... Dwarf galaxies • Dwarf galaxies are a crucial part of the galaxy evolution puzzle but we know very little about them. • Main theory (see later) proposes that galaxies built-up from smaller units through repeated merging. • Numerical simulations typically predict several thousand dark matter haloe ...
Measuring Astronomical Distances
... Important to have data at many different wavelengths Different instruments are capable of observing at different wavelengths This requires us to use more than one instrument ...
... Important to have data at many different wavelengths Different instruments are capable of observing at different wavelengths This requires us to use more than one instrument ...
The role of black holes in galaxy formation and evolution
... The energy that jets pump into cavities in a sound crossing time matches the heat needed to keep the gas in thermal equilibrium if this energy equals to pgasVcav with a scatter of a factor of four39 (Fig. 5a). This proportionality, which extends over four orders of magnitude, suggests a self-regulat ...
... The energy that jets pump into cavities in a sound crossing time matches the heat needed to keep the gas in thermal equilibrium if this energy equals to pgasVcav with a scatter of a factor of four39 (Fig. 5a). This proportionality, which extends over four orders of magnitude, suggests a self-regulat ...
3P15.pdf
... the photosphere to the total surface flux emitted by the star. Fig. 4a to 7a show, for all the stars of the sample, the mean value of the excess emission of the Hα line vs. the mean value of the excess emission of other chromospheric lines (Ca II λ8542Å, Ca II K, Hβ and Hγ). Fig. 4b to 7b show the s ...
... the photosphere to the total surface flux emitted by the star. Fig. 4a to 7a show, for all the stars of the sample, the mean value of the excess emission of the Hα line vs. the mean value of the excess emission of other chromospheric lines (Ca II λ8542Å, Ca II K, Hβ and Hγ). Fig. 4b to 7b show the s ...
click here
... • Stars of given type of spectrum and the same colors have the same absolute magnitude (99.9%) • Stars have different apparent magnitudes depending on their distance. • Stars behind dust clouds look redder than they are intrinsically, so… m-M=5 log d1 –5+ A(l) (i.e., the star looks fainter) ...
... • Stars of given type of spectrum and the same colors have the same absolute magnitude (99.9%) • Stars have different apparent magnitudes depending on their distance. • Stars behind dust clouds look redder than they are intrinsically, so… m-M=5 log d1 –5+ A(l) (i.e., the star looks fainter) ...
Evidence for 1000 km/s Molecular Outflows in the Local ULIRG
... velocity in the stacked spectrum, and an ambient density of 10 cm−3 (e.g. Veilleux et al. 1995), we drive an energy injection rate of ∼ 1.3 × 1044 ergs s−1 . Assuming an energy output per supernova of ∼ 1051 ergs (Veilleux et al. 1995), our estimated dE/dt yields a supernova rate, νSN,yr−1 of 4 yr−1 ...
... velocity in the stacked spectrum, and an ambient density of 10 cm−3 (e.g. Veilleux et al. 1995), we drive an energy injection rate of ∼ 1.3 × 1044 ergs s−1 . Assuming an energy output per supernova of ∼ 1051 ergs (Veilleux et al. 1995), our estimated dE/dt yields a supernova rate, νSN,yr−1 of 4 yr−1 ...
Astronomical Distance Determination
... Our eyes have evolved to be most sensitive to the light emitted by the sun. Hence the bolometric correction for the missed emission in the infrared and ultraviolet is small for the sun. The “visual” magnitude actually corresponds to the flux measured with a certain filter on the telescope. There are ...
... Our eyes have evolved to be most sensitive to the light emitted by the sun. Hence the bolometric correction for the missed emission in the infrared and ultraviolet is small for the sun. The “visual” magnitude actually corresponds to the flux measured with a certain filter on the telescope. There are ...
H II region
An H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived blue stars forged in these regions emit copious amounts of ultraviolet light that ionize the surrounding gas. H II regions—sometimes several hundred light-years across—are often associated with giant molecular clouds. The first known H II region was the Orion Nebula, which was discovered in 1610 by Nicolas-Claude Fabri de Peiresc.H II regions are named for the large amount of ionised atomic hydrogen they contain, referred to as H II, pronounced H-two by astronomers (an H I region being neutral atomic hydrogen, and H2 being molecular hydrogen). Such regions have extremely diverse shapes, because the distribution of the stars and gas inside them is irregular. They often appear clumpy and filamentary, sometimes showing bizarre shapes such as the Horsehead Nebula. H II regions may give birth to thousands of stars over a period of several million years. In the end, supernova explosions and strong stellar winds from the most massive stars in the resulting star cluster will disperse the gases of the H II region, leaving behind a cluster of birthed stars such as the Pleiades.H II regions can be seen to considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of other galaxies. Spiral and irregular galaxies contain many H II regions, while elliptical galaxies are almost devoid of them. In the spiral galaxies, including the Milky Way, H II regions are concentrated in the spiral arms, while in the irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the 30 Doradus region in the Large Magellanic Cloud and NGC 604 in the Triangulum Galaxy.