DUSTY CIRCUMSTELLAR DISKS B. Zuckerman
... have enabled detection of many stars that appear to be old or post T Tauri stars (e.g., Neuhäuser 1997). Such stars have been discovered because they emit many more X-rays than do older, main-sequence, stars. Not only did ROSAT enable detection of oldish T Tauri stars in regions surrounding various ...
... have enabled detection of many stars that appear to be old or post T Tauri stars (e.g., Neuhäuser 1997). Such stars have been discovered because they emit many more X-rays than do older, main-sequence, stars. Not only did ROSAT enable detection of oldish T Tauri stars in regions surrounding various ...
Where stars form: inside-out growth and coherent star formation from
... 2676 galaxies enabling a division into subsamples based on stellar mass and star formation rate. By creating deep stacked Hα images, we reach surface brightness limits of 1 × 10−18 erg s−1 cm−2 arcsec−2 , allowing us to map the distribution of ionized gas out to greater than 10 kpc for typical L∗ ga ...
... 2676 galaxies enabling a division into subsamples based on stellar mass and star formation rate. By creating deep stacked Hα images, we reach surface brightness limits of 1 × 10−18 erg s−1 cm−2 arcsec−2 , allowing us to map the distribution of ionized gas out to greater than 10 kpc for typical L∗ ga ...
Gas Mass Fractions and the Evolution of Spiral Galaxies
... luminosity and surface brightness. It is not correlated with linear size. Gas fraction varies with luminosity and surface brightness at the same rate, indicating evolution at fixed size. Dim galaxies are clearly less evolved than bright ones, having consumed only ∼ 1/2 of their gas. This resolves th ...
... luminosity and surface brightness. It is not correlated with linear size. Gas fraction varies with luminosity and surface brightness at the same rate, indicating evolution at fixed size. Dim galaxies are clearly less evolved than bright ones, having consumed only ∼ 1/2 of their gas. This resolves th ...
Project Description - SDSS-III
... expansion of the Universe. Large-scale imaging and spectroscopic surveys have revealed rich, complex structure in the outer Milky Way, residual traces of the Galaxy’s hierarchical formation history. These surveys have discovered more than a dozen new members of the Local Group of galaxies and identi ...
... expansion of the Universe. Large-scale imaging and spectroscopic surveys have revealed rich, complex structure in the outer Milky Way, residual traces of the Galaxy’s hierarchical formation history. These surveys have discovered more than a dozen new members of the Local Group of galaxies and identi ...
Quantitative constraints on starburst cycles in galaxies with stellar
... Gyr, is a factor of 5 higher for galaxies with stellar masses ∼ 108 M⊙ than for galaxies with M∗ ∼ 1010 M⊙ . A similar conclusion was recently reached by Bauer et al (2013), who analyzed the distribution of specific star formation rates as a function of stellar mass for galaxies with 0.05 < z < 0.32 ...
... Gyr, is a factor of 5 higher for galaxies with stellar masses ∼ 108 M⊙ than for galaxies with M∗ ∼ 1010 M⊙ . A similar conclusion was recently reached by Bauer et al (2013), who analyzed the distribution of specific star formation rates as a function of stellar mass for galaxies with 0.05 < z < 0.32 ...
Mapping the Pathways of Galaxy Transformation Across Time and
... quiescence. Many show signs of a recent galaxy-galaxy merger and a newly-evolved stellar bulge, and most have LINER-like emission, which may indicate low luminosity AGN activity. Thus, the study of this short-lived phase of galaxy evolution can address the connections among mergers, star formation h ...
... quiescence. Many show signs of a recent galaxy-galaxy merger and a newly-evolved stellar bulge, and most have LINER-like emission, which may indicate low luminosity AGN activity. Thus, the study of this short-lived phase of galaxy evolution can address the connections among mergers, star formation h ...
ESA BR-170 - ESA Science
... In 1800, the German-born British astronomer and musician, William Herschel – famous for his discovery of the planet Uranus a few years earlier – described that the differently coloured filters through which he observed the Sun allowed different levels of heat to pass. He performed a simple experimen ...
... In 1800, the German-born British astronomer and musician, William Herschel – famous for his discovery of the planet Uranus a few years earlier – described that the differently coloured filters through which he observed the Sun allowed different levels of heat to pass. He performed a simple experimen ...
The Nature of the Stars
... is moving. As the accompanying figure shows, a star’s space velocity v can be broken into components parallel and perpendicular to our line of sight. The component perpendicular to our line of sight—that is, across the plane of the sky—is called the star’s tangential velocity (vt). To determine it, ...
... is moving. As the accompanying figure shows, a star’s space velocity v can be broken into components parallel and perpendicular to our line of sight. The component perpendicular to our line of sight—that is, across the plane of the sky—is called the star’s tangential velocity (vt). To determine it, ...
Missions
... objects was published, including thousands of intriguing objects never seen before. A few years later more observations revealed the existence of distant galaxies whose radiation is stronger in the infrared than in the visible. There was no immediate explanation for this. Astronomers were seeing a q ...
... objects was published, including thousands of intriguing objects never seen before. A few years later more observations revealed the existence of distant galaxies whose radiation is stronger in the infrared than in the visible. There was no immediate explanation for this. Astronomers were seeing a q ...
Open clusters and associations in the Gaia era
... an issue if the survey does not extend beyond the cluster tidal radius, especially if there is mass segregation as the incompleteness level will then depend on mass. Moreover, objects might be missed around bright stars due to contrast issue, in crowded regions or in area with high extinction. As fo ...
... an issue if the survey does not extend beyond the cluster tidal radius, especially if there is mass segregation as the incompleteness level will then depend on mass. Moreover, objects might be missed around bright stars due to contrast issue, in crowded regions or in area with high extinction. As fo ...
Plotting the Rotation Curve of M31
... Radii in arcminutes and kiloparsecs and peak frequencies and velocities are listed in the table on page 3. How can we calculate the velocity of an atom from looking at its spectrum? Answer: measure the wavelength or frequency shift in the emission/absorption lines relative to a spectrum of the atom ...
... Radii in arcminutes and kiloparsecs and peak frequencies and velocities are listed in the table on page 3. How can we calculate the velocity of an atom from looking at its spectrum? Answer: measure the wavelength or frequency shift in the emission/absorption lines relative to a spectrum of the atom ...
ALMA - ESO
... high mass stars in our Galaxy, and evolved stars even in the LMC In evolved stars such as IRC+10216, ALMA will be able to image molecular and dust emission Herschel can be used to search for water vapor in the envelopes of such stars ...
... high mass stars in our Galaxy, and evolved stars even in the LMC In evolved stars such as IRC+10216, ALMA will be able to image molecular and dust emission Herschel can be used to search for water vapor in the envelopes of such stars ...
Metal-poor Stars
... Population III stars and concluded that long-lived low-mass star could not easily form from zero-metallicity gas, and hence were extremely rare, if not altogether absent. Today, we know that star formation in zero-metallicity gas indeed does not favor the creation of low-mass stars due to insufficie ...
... Population III stars and concluded that long-lived low-mass star could not easily form from zero-metallicity gas, and hence were extremely rare, if not altogether absent. Today, we know that star formation in zero-metallicity gas indeed does not favor the creation of low-mass stars due to insufficie ...
Digital Universe Guide - American Museum of Natural History
... Activating Data Groups In order to alter the properties of a data group (brightness, color, label size), you must make the data group active. By default, the stars are the active group when the Milky Way Atlas is launched. You can verify that by inspecting the active group indicator below the Groups ...
... Activating Data Groups In order to alter the properties of a data group (brightness, color, label size), you must make the data group active. By default, the stars are the active group when the Milky Way Atlas is launched. You can verify that by inspecting the active group indicator below the Groups ...
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... lower limit of Li abundance that can be measured is thus higher for O-rich stars than for C-rich stars. In both cases, a Li abundance determination can only be achieved with the help of spectral synthesis techniques including large numbers of molecular lines. Thus, the counterparts to the catalogues ...
... lower limit of Li abundance that can be measured is thus higher for O-rich stars than for C-rich stars. In both cases, a Li abundance determination can only be achieved with the help of spectral synthesis techniques including large numbers of molecular lines. Thus, the counterparts to the catalogues ...
FLARE SWG theme 3: high
... Pro: deeper spectroscopic follow-up observations Con: shorter wavelength (<2.5um) spectroscopy more limiting for quasar identification; however, again, most of first quasar emission lines at <2um ...
... Pro: deeper spectroscopic follow-up observations Con: shorter wavelength (<2.5um) spectroscopy more limiting for quasar identification; however, again, most of first quasar emission lines at <2um ...
Variations in Integrated Galactic Initial Mass Functions due to
... makes it hard to infer directly from the masses. Their strong effect on the upper mass limit for the clusters in a galaxy makes it detectable from a statistical point of view, though. See below for a discussion on how Schechter-like CMFs might influence the IGIMF effect. Here we took pure power-laws ...
... makes it hard to infer directly from the masses. Their strong effect on the upper mass limit for the clusters in a galaxy makes it detectable from a statistical point of view, though. See below for a discussion on how Schechter-like CMFs might influence the IGIMF effect. Here we took pure power-laws ...
The Origin and Evolution of Dust in Galaxies
... Star formation rate (SFR) > Gas injection rate from SNe and AGB LMC star formation depends on the large reservoir of existing ISM gas The LMC is getting gas poorer. The SFR is likely to be declining with time. Chemical evolution of the LMC ISM is very slow process (~1 Gyrs) – ISM gas : 8x108 Msun (H ...
... Star formation rate (SFR) > Gas injection rate from SNe and AGB LMC star formation depends on the large reservoir of existing ISM gas The LMC is getting gas poorer. The SFR is likely to be declining with time. Chemical evolution of the LMC ISM is very slow process (~1 Gyrs) – ISM gas : 8x108 Msun (H ...
Recen t Scien ti c
... of variable sources decreases moving out from the central region of M31. However, there are various systematic eects and biases (such as faint source detection limits changing with PSF) that need to be evaluated in order to conrm this trend. About 12 of the variable sources are classied as bright ...
... of variable sources decreases moving out from the central region of M31. However, there are various systematic eects and biases (such as faint source detection limits changing with PSF) that need to be evaluated in order to conrm this trend. About 12 of the variable sources are classied as bright ...
Multiwavelength observations of XTE J1118+480`s outburst
... 85% of sources are highly absorbed (X-ray observations): column density NH>1023 cm-2 X-ray absorption >> IR => absorbing matter local to neutron star ...
... 85% of sources are highly absorbed (X-ray observations): column density NH>1023 cm-2 X-ray absorption >> IR => absorbing matter local to neutron star ...
GALAXIES 626
... The bulge is not a dominant feature of our Galaxy - only about 25% of the light. The bulge is probably an evolutionary structure of the disk, rather than a feature of galaxy formation in the early universe. Structure and kinematics are well represented by the product of disk instability. The α-enhan ...
... The bulge is not a dominant feature of our Galaxy - only about 25% of the light. The bulge is probably an evolutionary structure of the disk, rather than a feature of galaxy formation in the early universe. Structure and kinematics are well represented by the product of disk instability. The α-enhan ...
Annual Report 2006/2007
... when the Universe was less than 5% of its present age. The theme of the NOVA Program is to unravel the history of the universe and to further develop the understanding of the life cycle of stars and galaxies. The NOVA research program concentrates on the following three interconnected areas: • Netw ...
... when the Universe was less than 5% of its present age. The theme of the NOVA Program is to unravel the history of the universe and to further develop the understanding of the life cycle of stars and galaxies. The NOVA research program concentrates on the following three interconnected areas: • Netw ...
Variations in the Star Formation Efficiency of the Dense Molecular
... to systematically study the effect of gas density on star formation over large parts of the universe. In this paper, we present new observations of the HCN (1–0) transition that cover large (∼ kpc) parts of nearby galaxy disks and compare them to estimates of the recent star formation rate and CO em ...
... to systematically study the effect of gas density on star formation over large parts of the universe. In this paper, we present new observations of the HCN (1–0) transition that cover large (∼ kpc) parts of nearby galaxy disks and compare them to estimates of the recent star formation rate and CO em ...
Galaxies
... Passively evolving galaxies. Early-type galaxies, with little or no star formation, represent roughly one-half of the present day stellar mass density (Bell et al. 2003). These galaxies formed their stars earlier and more rapidly than late-type galaxies. They are more strongly clustered. It is likel ...
... Passively evolving galaxies. Early-type galaxies, with little or no star formation, represent roughly one-half of the present day stellar mass density (Bell et al. 2003). These galaxies formed their stars earlier and more rapidly than late-type galaxies. They are more strongly clustered. It is likel ...
Serpens
Serpens (""the Serpent"", Greek Ὄφις) is a constellation of the northern hemisphere. One of the 48 constellations listed by the 2nd-century astronomer Ptolemy, it remains one of the 88 modern constellations defined by the International Astronomical Union. It is unique among the modern constellations in being split into two non-contiguous parts, Serpens Caput (Serpent's Head) to the west and Serpens Cauda (Serpent's Tail) to the east. Between these two halves lies the constellation of Ophiuchus, the ""Serpent-Bearer"". In figurative representations, the body of the serpent is represented as passing behind Ophiuchus between Mu Serpentis in Serpens Caput and Nu Serpentis in Serpens Cauda.The brightest star in Serpens is the red giant star Alpha Serpentis, or Unukalhai, in Serpens Caput, with an apparent magnitude of 2.63. Also located in Serpens Caput are the naked-eye globular cluster Messier 5 and the naked-eye variables R Serpentis and Tau4 Serpentis. Notable extragalactic objects include Seyfert's Sextet, one of the densest galaxy clusters known; Arp 220, the prototypical ultraluminous infrared galaxy; and Hoag's Object, the most famous of the very rare class of galaxies known as ring galaxies.Part of the Milky Way's galactic plane passes through Serpens Cauda, which is therefore rich in galactic deep-sky objects, such as the Eagle Nebula (IC 4703) and its associated star cluster Messier 16. The nebula measures 70 light-years by 50 light-years and contains the Pillars of Creation, three dust clouds that became famous for the image taken by the Hubble Space Telescope. Other striking objects include the Red Square Nebula, one of the few objects in astronomy to take on a square shape; and Westerhout 40, a massive nearby star-forming region consisting of a molecular cloud and an H II region.