... level, either as a shower of secondary particles from the resulting electromagnetic cascade or as a flash of Cherenkov light from the passage of these particles through the earth’s atmosphere. As in the CGRO range, γ-ray observations are severely limited by the charged cosmic particle flux which giv ...
Probing nuclear activity versus star formation at z ∼ 0.8 using near
... galaxies. However, when they only considered star-forming galaxies in the control sample (i.e. they discarded quiescent galaxies), they found roughly the same level of star formation as in the AGN hosts. A similar result was found by Lutz et al. (2010), based on submillimetre data of a sample of 895 ...
... galaxies. However, when they only considered star-forming galaxies in the control sample (i.e. they discarded quiescent galaxies), they found roughly the same level of star formation as in the AGN hosts. A similar result was found by Lutz et al. (2010), based on submillimetre data of a sample of 895 ...
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 ...
The Norma cluster (ACO3627) – II. The near-infrared Ks
... tages. While star-forming regions are bright at optical wavelengths, making optical observations particularly sensitive to galaxies where star formation is taking place, the NIR is much less affected by short bursts of star formation and therefore a better indicator of galaxy mass (Andreon & Pelló ...
... tages. While star-forming regions are bright at optical wavelengths, making optical observations particularly sensitive to galaxies where star formation is taking place, the NIR is much less affected by short bursts of star formation and therefore a better indicator of galaxy mass (Andreon & Pelló ...
Observational evidence for AGN feedback in early
... (e.g. Cimatti, Daddi & Renzini 2006; Wake et al. 2006; Rodighiero et al. 2007b). Until very recently, the predictions from semi-analytic models of hierarchical galaxy formation were in severe conflict with the observationally derived formation ages and time-scales of early-type galaxies. These model ...
... (e.g. Cimatti, Daddi & Renzini 2006; Wake et al. 2006; Rodighiero et al. 2007b). Until very recently, the predictions from semi-analytic models of hierarchical galaxy formation were in severe conflict with the observationally derived formation ages and time-scales of early-type galaxies. These model ...
story of telescope
... Historical changes are slow and occur over a period of time, and the history of ideas in human thought is no exception. But one particular event stands out above all in the history of science. In July 1609, Galileo Galilei used an instrument to look at stars, and the discoveries he reported changed ...
... Historical changes are slow and occur over a period of time, and the history of ideas in human thought is no exception. But one particular event stands out above all in the history of science. In July 1609, Galileo Galilei used an instrument to look at stars, and the discoveries he reported changed ...
The Life Cycle of Stars: Supernovae in Starbursts by Jason Kezwer
... monitoring program was aimed as a feasibility study to determine the practicality of a large scale near-IR LIRG/ULIRG imaging survey. Establishing the supernova rate in these dusty galaxies is an important step toward confirming theorized star formation rates and settling the debate between the domi ...
... monitoring program was aimed as a feasibility study to determine the practicality of a large scale near-IR LIRG/ULIRG imaging survey. Establishing the supernova rate in these dusty galaxies is an important step toward confirming theorized star formation rates and settling the debate between the domi ...
Stars, Galaxies, Superuniverses and the Urantia Book, by Frederick
... number since our galaxy is the second largest in our local cluster of about 30 galaxies, and thus may be considered to be an exceptionally large galaxy. There are many more small galaxies of the elliptical or globular types than there are of the spiral type such as our Milky Way. The information on ...
... number since our galaxy is the second largest in our local cluster of about 30 galaxies, and thus may be considered to be an exceptionally large galaxy. There are many more small galaxies of the elliptical or globular types than there are of the spiral type such as our Milky Way. The information on ...
2. The X-ray-Radio correlation for bulgeless galaxies
... The study of integrated light measurements in both the X-ray and Radio bands in galaxies allows for the identification of populations of new stars – and therefore, star formation processes – as well as markers for the presence of Active Galactic Nuclei. Correlations between the X-ray and Radio emiss ...
... The study of integrated light measurements in both the X-ray and Radio bands in galaxies allows for the identification of populations of new stars – and therefore, star formation processes – as well as markers for the presence of Active Galactic Nuclei. Correlations between the X-ray and Radio emiss ...
Science with IMACS on Magellan
... and are incorporated into a cluster. The photometric redshifts that will be obtained will be used to separate samples for more efficient spectroscopy. The ability of the f/2.4 camera to cover large areas of sky to great depth should also make IMACS an ideal instrument to follow-up non-optical search ...
... and are incorporated into a cluster. The photometric redshifts that will be obtained will be used to separate samples for more efficient spectroscopy. The ability of the f/2.4 camera to cover large areas of sky to great depth should also make IMACS an ideal instrument to follow-up non-optical search ...
FIRST STELLAR ABUNDANCES IN THE DWARF IRREGULAR
... detailed abundances analyses as will be shown in this work. In Fig. 2 the Hα profiles of the three stars are shown. To obtain the stellar line profiles, the contribution of the diffuse Hα emission of Sextans A which was found for all stars was subtracted as part of the ’sky’ subtraction in the extra ...
... detailed abundances analyses as will be shown in this work. In Fig. 2 the Hα profiles of the three stars are shown. To obtain the stellar line profiles, the contribution of the diffuse Hα emission of Sextans A which was found for all stars was subtracted as part of the ’sky’ subtraction in the extra ...
The Celestial Origin of Atoms
... a science in its own right, with its own quantitative analysis and predictions, open to confirmation by physical measurement. For example, the measured level of the solar neutrino flux, even though it does not coincide in detail with the expected value, attests to the truth of the basic ideas of nucle ...
... a science in its own right, with its own quantitative analysis and predictions, open to confirmation by physical measurement. For example, the measured level of the solar neutrino flux, even though it does not coincide in detail with the expected value, attests to the truth of the basic ideas of nucle ...
THE STAR FORMATION AND NUCLEAR ACCRETION HISTORIES OF NORMAL GALAXIES
... Survey (NDWFS), AGN and Galaxy Evolution Survey (AGES), and XBoötes Survey to measure the Xray evolution of 6146 normal galaxies as a function of absolute optical luminosity, redshift, and spectral type over the largely unexplored redshift range 0.1 < ∼z< ∼ 0.5. Because only the closest or brightes ...
... Survey (NDWFS), AGN and Galaxy Evolution Survey (AGES), and XBoötes Survey to measure the Xray evolution of 6146 normal galaxies as a function of absolute optical luminosity, redshift, and spectral type over the largely unexplored redshift range 0.1 < ∼z< ∼ 0.5. Because only the closest or brightes ...
Wolf-Rayet Stars
... is clumped (i.e., non-homogeneous) on small scales. If this is true, mass-loss estimates are too large — possibly by factors of 3 or more. This has very important implications for stellar evolution calculations. A change in Ṁ by only a factor of 2 (over a star’s life) has a profound influence on th ...
... is clumped (i.e., non-homogeneous) on small scales. If this is true, mass-loss estimates are too large — possibly by factors of 3 or more. This has very important implications for stellar evolution calculations. A change in Ṁ by only a factor of 2 (over a star’s life) has a profound influence on th ...
Properties of Wolf-Rayet Stars - Paul Crowther, University of Sheffield
... WR stars resulting in stellar temperatures, luminosities, ionizing fluxes, plus wind properties accounting for clumping. Chemical abundances of WN and WC stars are presented, including a discussion of neon abundances in WC and WO stars from Spitzer observations. Empirical evidence supporting metalli ...
... WR stars resulting in stellar temperatures, luminosities, ionizing fluxes, plus wind properties accounting for clumping. Chemical abundances of WN and WC stars are presented, including a discussion of neon abundances in WC and WO stars from Spitzer observations. Empirical evidence supporting metalli ...
The last gasps of VY CMa: Aperture synthesis and adaptive optics
... above 1% of the peak was detected to the north and north-east of the central source. Although the dust emission morphology is very similar at the three wavelengths, there are some departures at 1.65 µm where the scattering efficiency of the grains is higher. Unfortunately, fluctuations in the atmosp ...
... above 1% of the peak was detected to the north and north-east of the central source. Although the dust emission morphology is very similar at the three wavelengths, there are some departures at 1.65 µm where the scattering efficiency of the grains is higher. Unfortunately, fluctuations in the atmosp ...
Article PDF - IOPscience
... ABSTRACT. The present note updates the information published in my recent monograph on T he Galaxies of the L ocal Group. Highlights include (1) the addition of the newly discovered Cetus dwarf spheroidal as a certain member of the Local Group ; (2) an improved distance for the Sagittarius dwarf irr ...
... ABSTRACT. The present note updates the information published in my recent monograph on T he Galaxies of the L ocal Group. Highlights include (1) the addition of the newly discovered Cetus dwarf spheroidal as a certain member of the Local Group ; (2) an improved distance for the Sagittarius dwarf irr ...
The formation of disc galaxies in high-resolution moving
... particles whereas the rest of the simulation volume is filled with progressively higher mass particles whose mass grows with distance from the target galaxy. This saves computational time while still ensuring the correct cosmological tidal field and mass infall rate for the forming target galaxy. Th ...
... particles whereas the rest of the simulation volume is filled with progressively higher mass particles whose mass grows with distance from the target galaxy. This saves computational time while still ensuring the correct cosmological tidal field and mass infall rate for the forming target galaxy. Th ...
Article PDF - IOPscience
... galaxies, as seen through their stellar light distributions, contain enough physical information to offer this classification. We argue through the use of 240 images of nearby galaxies that three model-independent parameters measured on a single galaxy image reveal its major ongoing and past formation ...
... galaxies, as seen through their stellar light distributions, contain enough physical information to offer this classification. We argue through the use of 240 images of nearby galaxies that three model-independent parameters measured on a single galaxy image reveal its major ongoing and past formation ...
Introduction_to_pulsar_astronomy
... neutron stars. He predicts a very slow and steady spin-down for these objects, based on the fact that they must be losing rotational energy due to their large EM emission. If the pulsations were due to vibration, then the intensity of the oscillation should decrease, and the vibration period (a char ...
... neutron stars. He predicts a very slow and steady spin-down for these objects, based on the fact that they must be losing rotational energy due to their large EM emission. If the pulsations were due to vibration, then the intensity of the oscillation should decrease, and the vibration period (a char ...
A GMOS dissection of the line-of
... Statistical properties of high-z radio quasars may be more useful in determining importance of lensing ...
... Statistical properties of high-z radio quasars may be more useful in determining importance of lensing ...
Plotting the Rotation Curve of M31
... Apparent magnitude: 4.4 (magnitude of Sirius, brightest star in sky = ‐1.43, 100x brighter) Distance: 2.5 million ly or 780 kpc M31 and the Milky Way are approaching each other at 100 km s-1 M31 interacted with the dwarf galaxy M32 200 million years ago, leading to a disturbance in the spiral struct ...
... Apparent magnitude: 4.4 (magnitude of Sirius, brightest star in sky = ‐1.43, 100x brighter) Distance: 2.5 million ly or 780 kpc M31 and the Milky Way are approaching each other at 100 km s-1 M31 interacted with the dwarf galaxy M32 200 million years ago, leading to a disturbance in the spiral struct ...
Gamma-ray burst
Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the brightest electromagnetic events known to occur in the universe. Bursts can last from ten milliseconds to several hours. The initial burst is usually followed by a longer-lived ""afterglow"" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio).Most observed GRBs are believed to consist of a narrow beam of intense radiation released during a supernova or hypernova as a rapidly rotating, high-mass star collapses to form a neutron star, quark star, or black hole. A subclass of GRBs (the ""short"" bursts) appear to originate from a different process – this may be due to the merger of binary neutron stars. The cause of the precursor burst observed in some of these short events may be due to the development of a resonance between the crust and core of such stars as a result of the massive tidal forces experienced in the seconds leading up to their collision, causing the entire crust of the star to shatter.The sources of most GRBs are billions of light years away from Earth, implying that the explosions are both extremely energetic (a typical burst releases as much energy in a few seconds as the Sun will in its entire 10-billion-year lifetime) and extremely rare (a few per galaxy per million years). All observed GRBs have originated from outside the Milky Way galaxy, although a related class of phenomena, soft gamma repeater flares, are associated with magnetars within the Milky Way. It has been hypothesized that a gamma-ray burst in the Milky Way, pointing directly towards the Earth, could cause a mass extinction event.GRBs were first detected in 1967 by the Vela satellites, a series of satellites designed to detect covert nuclear weapons tests. Hundreds of theoretical models were proposed to explain these bursts in the years following their discovery, such as collisions between comets and neutron stars. Little information was available to verify these models until the 1997 detection of the first X-ray and optical afterglows and direct measurement of their redshifts using optical spectroscopy, and thus their distances and energy outputs. These discoveries, and subsequent studies of the galaxies and supernovae associated with the bursts, clarified the distance and luminosity of GRBs. These facts definitively placed them in distant galaxies and also connected long GRBs with the explosion of massive stars, the only possible source for the energy outputs observed.