Downloads & Free Reading Options - Results

We model the evolution of IR galaxies using a phenomenological approach to match the observed source counts at different IR wavelengths. We introduce a new algorithm for reproducing source counts based on direct integration of probability distributions rather than Monte-Carlo sampling. We construct a simple model for the evolution of the luminosity function and the colour distribution of IR galaxies which utilizes a minimum number of free parameters. Moreover we analyze how each of these parameters is constrained by observational data. The model is based on pure luminosity evolution and adopts the Dale & Helou SED templates. We find that the 850um source counts and their redshift distribution depend strongly on the shape of the luminosity evolution function, but only weakly on the details of the SEDs. We derive the best-fit evolutionary model using the 850um counts and redshift distribution as constraints. Moreover our best-fit shows a flattening of the faint end of the luminosity function towards high redshifts and requires a colour evolution which implies the typical dust temperatures of objects with the same luminosities to decrease with redshift. We compare our best-fit model to observed source counts at shorter and longer wavelengths which indicates our model reproduces the 70um and 1100um source counts remarkably well, but under-produces the counts at intermediate wavelengths. Analysis reveals that the discrepancy arises at low redshifts, indicating that revision of the adopted SED library towards lower dust temperatures (at a fixed infrared luminosity) is required. This modification is equivalent to a population of cold galaxies existing at low redshifts, as also indicated by recent Herschel results, which are underrepresented in IRAS sample. We show that the modified model successfully reproduces the source counts in a wide range of IR and submm wavelengths.

The significance of the Ly{\alpha} emission line as a probe of the high-redshift Universe has long been established. Originating mainly in the vicinity of young, massive stars and in association with accretion of large bulks of matter, it is ideal for detecting young galaxies, the fundamental building blocks of our Universe. Since many different processes shape the spectrum and the spatial distribution of the Ly{\alpha} photons in various ways, a multitude of physical properties of galaxies can be unveiled. However, this also makes the interpretation of Ly{\alpha} observations notoriously difficult. Because Ly{\alpha} is a resonant line, it scatters on neutral hydrogen, having its path length from the source to our telescopes vastly increased, and taking it through regions of unknown physical conditions. In this work, a numerical code capable of calculating realistically the radiative transfer of Ly{\alpha} is presented. The code is capable of performing the radiative transfer in an arbitrary and adaptively refined distribution of Ly{\alpha} source emission, temperature and velocity field of the interstellar and intergalactic medium, as well as density of neutral and ionized hydrogen, and, particularly important, dust. Accordingly, it is applied to galaxies simulated at high resolution, yielding a number of novel and interesting results, most notably the escape fractions of Ly{\alpha} photons, the effect of dust on the line profile, and the impact of the transfer through the intergalactic medium. Furthermore, the remarkable detection of Ly{\alpha} emission from a so-called "damped Ly{\alpha} absorber" --- a special type of objects thought to be the progenitor of present-day's galaxies --- is presented, and the potential of the code for interpreting observations is demonstrated.

The significance of the Ly{\alpha} emission line as a probe of the high-redshift Universe has long been established. Originating mainly in the vicinity of young, massive stars and in association with accretion of large bulks of matter, it is ideal for detecting young galaxies, the fundamental building blocks of our Universe. Since many different processes shape the spectrum and the spatial distribution of the Ly{\alpha} photons in various ways, a multitude of physical properties of galaxies can be unveiled. However, this also makes the interpretation of Ly{\alpha} observations notoriously difficult. Because Ly{\alpha} is a resonant line, it scatters on neutral hydrogen, having its path length from the source to our telescopes vastly increased, and taking it through regions of unknown physical conditions. In this work, a numerical code capable of calculating realistically the radiative transfer of Ly{\alpha} is presented. The code is capable of performing the radiative transfer in an arbitrary and adaptively refined distribution of Ly{\alpha} source emission, temperature and velocity field of the interstellar and intergalactic medium, as well as density of neutral and ionized hydrogen, and, particularly important, dust. Accordingly, it is applied to galaxies simulated at high resolution, yielding a number of novel and interesting results, most notably the escape fractions of Ly{\alpha} photons, the effect of dust on the line profile, and the impact of the transfer through the intergalactic medium. Furthermore, the remarkable detection of Ly{\alpha} emission from a so-called "damped Ly{\alpha} absorber" --- a special type of objects thought to be the progenitor of present-day's galaxies --- is presented, and the potential of the code for interpreting observations is demonstrated.

Includes bibliographies and index

We combine the GALFORM semi-analytical model of galaxy formation, which predicts the star formation and merger histories of galaxies, the GRASIL spectro-photometric code, which calculates the spectral energy distributions (SEDs) of galaxies self-consistently including reprocessing of radiation by dust, and artificial neural networks (ANN), to investigate the clustering properties of galaxies selected by their emission at submillimetre wavelengths (SMGs). We use the Millennium Simulation to predict the spatial and angular distribution of SMGs. At redshift z = 2, we find that these galaxies are strongly clustered, with a comoving correlation length of r0 = 5.6 \pm 0.9 Mpc/h for galaxies with 850{\mu}m flux densities brighter than 5 mJy, in agreement with observations. We predict that at higher redshifts these galaxies trace denser and increasingly rarer regions of the universe. We present the predicted dependence of the clustering on luminosity, submillimetre colour, halo and total stellar masses. Interestingly, we predict tight relations between correlation length and halo and stellar masses, independent of sub-mm luminosity.

We present the Seyfert and star formation Activity in the Far-InfraRed (SAFIR) project, a small (15.1h) Herschel guaranteed time proposal performing PACS and SPIRE imaging of a small sample of nearby Seyfert galaxies. This project is aimed at studying the physical nature of the nuclear IR emission by means of multi-component spectral energy distribution (SED) fitting and the star formation properties of AGN hosts, as traced by cold dust. We summarize the results achieved so far and outline the on-going work.

We present the Seyfert and star formation Activity in the Far-InfraRed (SAFIR) project, a small (15.1h) Herschel guaranteed time proposal performing PACS and SPIRE imaging of a small sample of nearby Seyfert galaxies. This project is aimed at studying the physical nature of the nuclear IR emission by means of multi-component spectral energy distribution (SED) fitting and the star formation properties of AGN hosts, as traced by cold dust. We summarize the results achieved so far and outline the on-going work.

We present the Seyfert and star formation Activity in the Far-InfraRed (SAFIR) project, a small (15.1h) Herschel guaranteed time proposal performing PACS and SPIRE imaging of a small sample of nearby Seyfert galaxies. This project is aimed at studying the physical nature of the nuclear IR emission by means of multi-component spectral energy distribution (SED) fitting and the star formation properties of AGN hosts, as traced by cold dust. We summarize the results achieved so far and outline the on-going work.

In the past decade, our understanding of galaxy evolution has been revolutionized by the discovery that luminous, dusty, starburst galaxies were 1,000 times more abundant in the early Universe than at present. It has, however, been difficult to measure the complete redshift 2 distribution of these objects, especially at the highest redshifts (z > 4). Here we report a redshift survey at a wavelength of three millimeters, targeting carbon monoxide line emission from the star-forming molecular gas in the direction of extraordinarily bright millimetrewave-selected sources. High-resolution imaging demonstrates that these sources are strongly gravitationally lensed by foreground galaxies. We detect spectral lines in 23 out of 26 sources and multiple lines in 12 of those 23 sources, from which we obtain robust, unambiguous redshifts. At least 10 of the sources are found to lie at z > 4, indicating that the fraction of dusty starburst galaxies at high redshifts is greater than previously thought. Models of lens geometries in the sample indicate that the background objects are ultra-luminous infrared galaxies, powered by extreme bursts of star formation.

The Wide-field Infrared Survey is a medium class Explorer mission that was launched onl4Dec 2009. WISE should detect hundreds of millions of stars and galaxies, including millions of ULIRGS and QSOs; hundreds of thousands of asteroids; and hundreds of cold brown dwarfs. The telescope cover was ejected on 29 Dec 2009 and the all-sky survey started on 14 Jan 2010. WISE takes more the 7000 framesets per day, with each frameset covering 0.6 square degrees in four bands centered at 3.4, 4.6, 12 and 22 microns. WISE is well-suited to the discovery of brown dwarfs, ultraluminous infrared galaxies, and near-Earth objects. With an angular resolution of 6 arcsecouds at 12 microns, a 5(sigma) point-source sensitivity of around 1 mJy at 12 microns and 6 mJy at 22 microns, and coverage of over 99% of the sky, WISE also provides a powerful database for the study of the dusty ISM in our own galaxy. A preliminary release of WISE data will be made available to the community 6 months after the end of the cryogenic survey, or about May 2011. The final data release will be 11 months later, about April 2012.

We introduce a new technique based on artificial neural networks which allows us to make accurate predictions for the spectral energy distributions (SEDs) of large samples of galaxies, at wavelengths ranging from the far-ultra-violet to the sub-millimetre and radio. The neural net is trained to reproduce the SEDs predicted by a hybrid code comprised of the GALFORM semi-analytical model of galaxy formation, which predicts the full star formation and galaxy merger histories, and the GRASIL spectro-photometric code, which carries out a self-consistent calculation of the SED, including absorption and emission of radiation by dust. Using a small number of galaxy properties predicted by GALFORM, the method reproduces the luminosities of galaxies in the majority of cases to within 10% of those computed directly using GRASIL. The method performs best in the sub-mm and reasonably well in the mid-infrared and the far-ultra-violet. The luminosity error introduced by the method has negligible impact on predicted statistical distributions, such as luminosity functions or colour distributions of galaxies. We use the neural net to predict the overlap between galaxies selected in the rest-frame UV and in the observer-frame sub-mm at z=2. We find that around half of the galaxies with a 850um flux above 5 mJy should have optical magnitudes brighter than R_AB < 25 mag. However, only 1% of the galaxies selected in the rest-frame UV down to R_AB < 25 mag should have 850um fluxes brighter than 5 mJy. Our technique will allow the generation of wide-angle mock catalogues of galaxies selected at rest-frame UV or mid- and far-infrared wavelengths.

Using the UltraVISTA DR1 and 3D-HST catalogs, we construct a stellar-mass-complete sample, unique for its combination of surveyed volume and depth, to study the evolution of the fractions of quiescent galaxies, moderately unobscured star-forming galaxies, and dusty star-forming galaxies as a function of stellar mass over the redshift interval $0.2 \le z \le 3.0$. We show that the role of dusty star-forming galaxies within the overall galaxy population becomes more important with increasing stellar mass, and grows rapidly with increasing redshift. Specifically, dusty star-forming galaxies dominate the galaxy population with $\log{(M_{\rm star}/M_{\odot})} \gtrsim 10.3$ at $z\gtrsim2$. The ratio of dusty and non-dusty star-forming galaxies as a function of stellar mass changes little with redshift. Dusty star-forming galaxies dominate the star-forming population at $\log{(M_{\rm star}/M_{\odot})} \gtrsim 10.0-10.5$, being a factor of $\sim$3-5 more common, while unobscured star-forming galaxies dominate at $\log{(M_{\rm star}/M_{\odot})} \lesssim 10$. At $\log{(M_{\rm star}/M_{\odot})} > 10.5$, red galaxies dominate the galaxy population at all redshift $z

1Masters of Space

By Edward Everett Evans and E. E. Smith

The Masters had ruled all space with an unconquerable iron fist. But the Masters were gone. And this new, young race who came now to take their place--could they hope to defeat the ancient Enemy of All? (Summary by Gutenberg)

This is a bilingual project. The first part, in Hebrew, is the story "Injustice" by Yosef Haim Brenner, written following the conquest of Palestine by the British troops during WWI. The story takes place on the Turkish side of the dividing line between the combating forces. An escaped British prisoner of war had taken shelter among a group of Jewish workers, who, following a heated discussion, turned him over to the Turkish army. The second part of this project, in English, is a chapter in the book "The Escaping Club," written in 1922 by the same British prisoner of war, the aviator A. J. Evans, who gave his account of the same event. (Summary by Omri Lernau)

3Escaping Club

By A. J. Evans

Described by some as one of the greatest escape books published. <i>The Escaping Club</i> recounts Evans' escape to Switzerland from a supposedly "escape-proof" German prison camp during World War I. After repatriation and rejoining the war, Evans again finds himself captured, this time first by Arabs and then by Turks. He again manages to escape. A detailed look at the trials faced by Allied POWs during World War I. (Summary by Tom Weiss)

4College Freshman's Don't Book

By George Fullerton Evans

A short, humorous guide of what not to do in your first year of college. (Summary by Jill Engle)

5Masters of Space

By Edward Everett Evans and E. E. Smith

The Masters had ruled all space with an unconquerable iron fist. But the Masters were gone. And this new, young race who came now to take their place—could they hope to defeat the ancient Enemy of All? - Summary from Gutenberg text

One of the very first New Zealand novels, Over the Hills and Far Away is a heavily romanticised tale of a woman's journey from England to Otago, New Zealand, and her subsequent experiences in the wild new colony. - Summary by Lewis Fletcher

7Planet Mappers

By Edward Everett Evans

The Carver family are out in space, travelling to new worlds to check them out for colonization. But, when Mr. Carver has an accident, and remains out of commission for the trip, his sons, Jon and Jak, step up and take over their trip. The boys use their different talents to make their journey a successful one! (Ann Boulais)

Sonnets from The Patagonian is a collection of sonnets and the first work published by the short-lived Claire Marie press. Each sonnet is a portrait of someone Evans knows from the Modernist scene just beginning to coalesce in Greenwich Village, and each portrait is dedicated to a completely different acquaintance. (Evans's portraits of his friend Allen Norton are dedicated to the critic Carl Van Vechten, for instance, and his portraits of himself are dedicated to Allen Norton. His portrait of Carl Van Vechten is dedicated to Gertrude Stein.) What emerges is a clever, irreverent, set of early Modernist in-jokes that look forward to the Dadaist and Surrealist movements that would form in Europe after World War I. Giddy, bizarre and deftly constructed, Sonnets from the Patagonian read like nothing else of its time. Evans owned and managed the Claire Marie press and during the year it existed, he published only six titles, including Tender Buttons by Getrude Stein. It is for Tender Buttons that Claire Marie and Donald Evans are best remembered, if they are remembered at all. While it lasted, the press exerted an outsized influence on the world of Modernist art and literature in New York. Evans was an associate of Stein, Van Vechten, Mabel Luhan Dodge, Walter Conrad Arensberg and Wallace Stevens. He published three more books before his death in 1921, allegedly by suicide. Summary by Wes Freeman.

9St. Elmo

By Augusta Jane Evans

Written in prose and full of references to religion and mythology, this book tells the love story between St. Elmo and Edna. He is cynical and worldly, she is as beautiful as a nymph. The book was very popular during the 19th century and inspired movies and plays. It is even claimed that Rhett Butler from Gone With The Wind was inspired by St. Elmo Murray. - Summary by Stav Nisser.

10Man of Many Minds

By Edward Everett Evans

GALAXY IN DANGER!<br> Somewhere, somehow, the first moves have been made—the pattern is beginning to emerge. Someone—or something—is on the way to supreme power over all the planets held by Man.<br> And the Inter-stellar Corps is helpless to meet the threat—no normal man can hope to penetrate the conspiracy.<br> But—the Corps has a man who isn't normal, a man with a very strange weapon...<br> ...his mind.<br> Exciting! Strange! Extraordinary! One of the most unusual science fiction adventures ever published. <br><br>Space travel, telepathy, and heroism! Military school cadet George Hanlon is selected to join an elite, super-secret, secret service organization. He has extraordinary mental powers, among them the ability to talk to animals and transfer parts of his mind into them. Old-school space opera! (Summary by TriciaG and from the preface)

Born in London of Welsh parents, George Essex Evans was raised and educated by his mother Mary Ann (née Owen) in Pembrokeshire after she was widowed when George was only a few months old. Emigrating to Queensland with his siblings to Australia at age 17 with the intention of farming, Evans was badly injured in a horse-riding accident, when he was thrown against a tree and was unable to do any physical work. Evans was described as a reserved man, and at times rather moody and impulsive. However, he was also described as a kind person and a loyal friend. He had a strong sense of honour and self-respect, traits that made him a model husband and father. Evans was described as having a tremendous memory, particularly for poetic verse, of which he was able to recite a prodigious amount. Few of his contemporaries were able to match his breadth of knowledge of English, American, and Australian poetry. Summary by Wikipedia

A retelling of the classic fairy-tale, illustrated by one of the leading figures in the Golden Age of book illustration. Never underestimate the importance of receiving an invitation to significant social events. (Summary by mlcui)