29,395 research outputs found
The Ages of Elliptical Galaxies from Mid-Infrared Emission
No full textThe mid-infrared (10–20 m) luminosity of elliptical galaxies is dominated by the integrated emission from
circumstellar dust in red giant stars. As a single stellar population evolves, the rate of dusty mass loss from red giant
stars decreases with time, so the mid-infrared luminosity should also decline with stellar age. To seek such a
correlation, we have used archival Infrared Space Observatory (ISO) observations to determine surface brightness
profiles and central fluxes at 15 m in 17 early-type galaxies for which stellar ages have been determined from
optical spectral indices. The radial surface brightness distributions at 15 m generally follow the stellar de Vaucouleurs
profile, as expected. We find that the surface brightness ratio 15 m=I band is systematically higher in
elliptical galaxies with ages P5 Gyr and in galaxies that exhibit evidence of recent mergers. Within the accuracy
of our observations, 15 m=I band shows no age dependence for ages k5 Gyr. The corresponding flux ratios
F15 m=FI band within apertures scaled to the effective radius (Re=8) are proportional to the 15 m=I band ratios at
larger galactic radii, indicating that no 15 m emission is detected from central dust clouds visible in optical images
in some of our sample galaxies. Emission at 15 m is observed in noncentral massive clouds of dust and cold gas in
NGC 1316, an elliptical galaxy that is thought to have had a recent merger. Recent Spitzer Space Telescope data also
indicate the presence of polycyclic aromatic hydrocarbon (PAH ) emission at 8 m. Several ellipticals have extended
regions of 15 m emission that have no obvious counterparts at other frequencies
Absence of Dwarf Galaxies at High Redshifts: Evidence from a Galaxy Group
No full textThe galaxy group NGC 5044 consists of a luminous giant elliptical galaxy surrounded by a cluster of 160
low-luminosity and dwarf galaxies, mostly of early type. The cumulative projected radial distribution of dwarf
galaxies in the NGC 5044 group, unlike distributions of more luminous galaxies in rich clusters, does not follow
a projected dark matter (NFW ) profile. A deficiency or absence of low-luminosity galaxies is apparent in
NGC 5044 within about 350 kpc. Most of the dwarf galaxies in NGC 5044 entered the virial radius at redshifts
z P2:5(af =0:25), where af 1⁄4 1=(1þ zf ) is the epoch of group formation, and very few entered during redshifts
z k2:5(af =0:25). The peculiar, non-NFW shape of the projected cumulative dwarf galaxy distribution in NGC
5044 within 350 kpc resembles the characteristic cumulative distribution of dark subhalos that are also known to
be relatively young. Dynamical friction is unlikely to explain the apparent lack of group member galaxies at small
radii in NGC 5044
Ultralow Iron Abundances in the Distant Hot Gas in Galaxy Groups
No full textA new XMM observation of the outer regions of the galaxy group NGC 5044 indicates hot gas iron abundances
of only between rvir and 0.4rvir ZFe /Z, ∼ 0.15 r p 0.2 . While the total baryon mass within the virial radius may be
close to the cosmic mean value observed in rich clusters, the ratio of total iron mass to optical light in NGC 5044
is about 3 times lower than that in rich clusters. The remarkably low iron abundance over a large volume of the
intergroup gas in the outer regions of NGC 5044 cannot be easily understood in terms of the outflow of enriched
gas in a group wind during its early history or by the long-term enrichment by the group member galaxies that
currently occupy this region. It is possible that the stars in NGC 5044 did not produce iron with the same efficiency
as in clusters, or that the iron resides in nonluminous clouds or stars, or that the entropy of the iron-enriched gas
created in early galactic starburst winds was too high to penetrate the group gas of lower entrop
Mathews/Matthews, Julia, Death Certificate, 1916
No full textDeath certificate for Julia Mathews.
Age: 45 years
Death Date: May 18, 1916
Cause: Cirrhosis
Burial Date: May 21, 1916
Location: Zion Cemetery, Tampa, Hillsborough County, Florida
Father: J. Long of South Carolina
Mother: Penni Long
Undertaker: C. W. Patterson, G. G. Hall
Informant: Cara Hal
W. H. Mathews Symposium: A celebration
No full text On June 30, 1984, Bill Mathews retired from full-time teaching in the Department of Geological Sciences at the University of British Columbia (UBC). On October 10, 1984, a large group of his friends and admirers met in a symposium to honour his immense contributions to science and to students of the Earth, but more importantly, to celebrate his continuing intense scientific activity. His personal and scientific vigour continues unabated, and "retirement" only means the opportunity to concentrate on his research, full-time.Bill Mathews is a phenomenon. It is not easy to keep up with the list of his publications, let alone to emulate his productivity. Since his first scientific publication in 1942, he has written 125 papers, which translates into three papers every year for 42 years! Now that he can devote himself entirely to this work, we can only suppose that this productivity will increase.W. H. Mathews received the B.A.Sc. degree in Geological Engineering from UBC in 1940 and the M.A.Sc. from UBC in 1941 and spent the war years in strategic minerals research with the B.C. Department of Mines, following which he continued his studies, receiving the Ph.D. from University of California, Berkeley, in 1948. In 1951 he joined the faculty at UBC, and he served as Head of the Department of Geology from 1964 to 1971. Dr. Mathews has been honoured by scientific societies and is a Professional Engineer, Fellow of the Geological Society of America, a member of the American Association of Petroleum Geologists and of the Geological Association of Canada, and a Fellow of the Royal Society of Canada.Perhaps the most striking feature of the symposium to honour Bill Mathews was the recognition of the breadth of his contributions. He calls himself a geomorphologist and Quaternary geologist, but the titles of his papers tell a different story. They tell of a man interested in everything at a fundamental and penetrating level, who has made important contributions to glaciology, volcanology, Tertiary tectonics, coal geology, mineral deposits, structural geology, geochronology, sedimentology, stratigraphy, engineering geology, and marine geology. It is very rare to find such a person, who can carry on a high-level scientific conversation with any specialist in the subdisciplines of the Earth sciences. Most of us are content to struggle with some mastery of a single subdiscipline, but Bill's curiosity reaches into every corner. This catholicity of interest has been a wonderful stimulus for his graduate students, undergraduate students, and colleagues.The four papers that follow this introduction were presented at the symposium and are kept together in this issue of the Canadian Journal of Earth Sciences as a tribute to Bill Mathews and in recognition of the astonishing range of his interests and contributions. We are pleased to celebrate in this way his return to full-time research after a career of combining his research with the full-time work of a distinguished professor.As is always the case, many of Bill's scientific friends could not produce a manuscript and symposium lecture in time to appear in this issue. Without exception, however, they join us in our applause of Bill Mathews' distinguished and continuing scientific career. </jats:p
Some Observations on the Construction of Space in the Prose of W. G. Sebald
No full textPierwodruk: „Białostockie Studia Literaturoznawcze” 2016, nr 8.This essay discusses the relationship between how space is constructed in the works of W. G. Sebald, and a fundamental characteristic of his texts, namely their hybridity. The author focuses, in particular, on the function of photography in Sebald’s narrations. Photographs, though themselves iconographic signs with strong referentiality, do not eliminate a strong textualization of space in Sebald’s works.Katedra Teorii Literatury, Uniwersytet Łódzki814115
Stopping Cooling Flows with Jets
No full textWe describe two-dimensional gasdynamical models of jets that carry mass as well as energy to the hot gas in
galaxy clusters. These flows have many attractive attributes for solving the galaxy cluster cooling flow problem: why
the hot gas temperature and density profiles resemble cooling flows but show no spectral evidence of cooling to low
temperatures. Using an approximate model for the cluster A1795, we show that mass-carrying jets can reduce the
overall cooling rate to or below the low values implied by X-ray spectra. Biconical subrelativistic jets, described by
several ad hoc parameters, are assumed to be activated when gas flows toward or cools near a central supermassive
black hole. As the jets proceed out from the center, they entrain more and more ambient gas. The jets lose internal
pressure by expansion and are compressed by the ambient cluster gas, becoming rather difficult to observe. For a wide
variety of initial jet parameters and several feedback scenarios, the global cooling can be suppressed for many
gigayears while maintaining cluster temperature profiles similar to those observed. The intermittency of the feedback
generates multiple generations of X-ray cavities similar to those observed in the Perseus Cluster and elsewhere
Energetics of X-Ray Cavities and Radio Lobes in Galaxy Clusters
No full textWe describe the formation and evolution of X-ray cavities in the hot gas of galaxy clusters. The cavities are formed
only with relativistic cosmic rays that eventually diffuse into the surrounding gas. We explore the evolution of cavities
formed with a wide range of cosmic ray diffusion rates. In previous numerical simulations, in which cavities are formed
by injecting ultrahot but nonrelativistic gas, cavity formation contributes thermal energy that may offset radiative losses
in the gas, thereby helping to solve the cooling flow problem. Contrary to these results, we find that X-ray cavities
formed solely from cosmic rays have a global cooling effect. Most cosmic rays in our cavity evolutions do not move
beyond the cooling radius, and, as cluster gas is displaced by comsic rays, it expands and globally cools. As cosmic rays
diffuse away from the cavities, the nearby gas becomes buoyant, resulting in a significant outward mass transfer within
the cooling radius, carrying relatively low entropy gas containing cosmic rays to outer regions in the cluster, where
it remains for times exceeding the local cooling time in the hot gas. This postcavity mass outflow due to cosmic-ray
buoyancy may contribute significantly toward solving the cooling flow problem. Cavities formed with cosmic rays
are more stable and more long-lived than those formed from ultrahot gas. The product of pressure and volume, PV,
varies with time and is a very inaccurate measure of the total energy released. We describe the energetics, size, and
buoyant rise of X-ray cavities in detail, showing how each depends on the rate of cosmic-ray diffusion
Thermal Evolution of Supernova Iron in Elliptical Galaxies
No full textInterpretations of the spatial distribution, abundance ratios, and global masses of metals in the hot gas of galaxy
clusters in terms of supernova enrichment have been problematical. For example, the abundance of iron and other
elements occasionally declines toward the center just where the stellar and supernova densities are highest. Also,
the mass of gas-phase iron per unit stellar mass or light is lower in elliptical galaxies and groups than in rich galaxy
clusters. We discuss hypothetical scenarios in which these abundance anomalies can result from the preferential
buoyant separation of metals. However, in this and all previous attempts to explain these metallicity observations it
has been assumed that all metals created by supernovae are present in either visible stars or the hot gas. We discuss
here the possibility that some of the iron expelled into the hot gas by Type Ia supernovae may have radiatively
cooled, avoiding detection by X-ray and optical observers. Hydrodynamic models of Type Ia explosions in the hot
gas inside elliptical galaxies create a gas of nearly pure iron that is several times hotter than the local interstellar gas.
We describe the subsequent thermal evolution of the iron-rich gas as it radiates and thermally mixes with the surrounding
gas. There is a critical time by which the iron ions must mix into the ambient gas to avoid rapid radiative
cooling. We find that successful mixing is possible if the iron ions diffuse with large mean free paths, as in an unmagnetized
plasma. However, the Larmor radii of the iron ions are exceptionally small in microgauss fields, so the
field geometry must be highly tangled or radial to allow the iron to mix by diffusion faster than it cools by radiative
losses. The possibility that some of the supernova iron cools cannot be easily discounted
Rhynchotermes diphyes Mathews
No full textRhynchotermes diphyes Mathews Rhynchotermes diphyes Mathews 1977: 157 –159 (major soldier, fig 103; minor soldier, 104); Krishna et al. 2013: 1472 (catalog). Holotype. Major soldier. 06.vi. 1967, A. G. Mathews col., MZUSP 7414, examined. Type locality. BRAZIL. Mato Grosso: Ribeirão Cascalheira, lat 12.8145 S, long 51.7745 W. (R.Constantino, personal comm.). New synonym: Rhynchotermes nyctobius Mathews 1977: 156 –157 (soldier, fig. 101). Holotype: soldier. BRAZIL. Mato Grosso: Ribeirão Cascalheira (MZUSP 7415), examined. Imago. Unknown. Soldier (Fig. 3 D, E, 4 D, E, 5 D, E, 7 C). Dimorphic. Major soldier: head capsule pear-shaped in dorsal view (Fig. 3 D). Antennal articles short (Fig. 4 D). Labrum tongue-shaped with hyaline tip. Frontal tube approximately equal in length to head, conical. Dorsal margin of head plus and margin of frontal tube concave in profile. Mandible evenly curved (Fig. 5 D), robust, with subrectangular marginal tooth, apical region of each mandible aligns to the proximal region of the opposite mandible when closed. Postmentum subquadrangular. Forecoxa process conical (Fig. 7 C). Head capsule with four to six long bristles. Labrum with two bristles. Pronotum with two long bristles either side of lateral lobe. Forecoxa process with short bristles. Head capsule orange to brown, body yellow. Minor soldier: head capsule rounded (Fig. 3 E). Length of frontal tube one-third longer than length of head without frontal tube, subcylindrical, slightly down-curved. Mandible thin (Fig. 5 E). Forecoxa process cylindrical. Head capsule with six to ten long bristles. Measurements given in Table 3. Worker (Fig. 9 C). Fontanelle conspicuous. Postclypeus medium line light, inconspicuous. Two sets of short bristles with darkened tips next to fontanelle. Measurements given in Table 2. Biological notes. Rhynchotermes diphyes has also been observed occupying abandoned termite nests (Cancello 1997) as well as the bulbs of banana plants and cattle dung. Comparisons. Mathews (1977) stated that the distinguishing features between the minor soldiers of R. diphyes and R. nyctobius were the curvature near the frontal tube tip of R. nyctobius and fewer bristles on head capsule of R. diphyes. However, after examining numerous samples, we were not able to confirm these differences as these characters are highly variable within and between samples such that it is impossible to separate the minor soldiers of the two species. On the other hand, the major soldier of R. diphyes has a large head capsule and a shorter, conical frontal tube whilst in other species (except R. bulbinasus which is bulbous) the frontal tube is equal or greater in length to the head capsule. Other material examined. BRAZIL. Mato Grosso: Chapada dos Guimarães, 25.xi. 1984, C. Campaner col., MZUSP 16132; Cláudia, 25.viii. 2011, Q. C. L. Santos col., MZUSP 15934; 20.viii. 2011, MZUSP 15933; Ribeirão Cascalheira, lat 12.8145 S, long 51.7745 W, 04.iv. 1968, A. G. Mathews col., MZUSP 7415; lat 12.0000S, long 59.5000W, viii. 1980, A. E. Mill col., MZUSP 10844; Utiariti (325m), Rio Papagaio, vii–viii. 1961, K. Lenko col., MZUSP 2043; São Paulo: Bauru, Aimorés, vi. 1947, D. Braz col., MZUSP 3050, 3052; Descalvado, 27.viii. 1944, Jandira & Otto Schubart col., MZUSP 0108; Novo Horizonte, 23.xi. 1944, R. L. Araujo & Silva col., MZUSP 2646; Luis Antônio, Reserva Jataí, 17.iv. 2001, E. M. Cancello et al. col., MZUSP 11236, 11237; 07.v. 2009, G. P. Paciência col., MZUSP 16113; Santa Rita do Passa Quatro, 22.vii. 1999, A. M. Costa-Leonardo leg., UnB 1269. Additional records. BRAZIL. Mato Grosso do Sul, Aquidauana (HF Cunha pers. comm.).Published as part of Constantini, Joice P. & Cancello, Eliana M., 2016, A taxonomic revision of the Neotropical termite genus Rhynchotermes (Isoptera, Termitidae, Syntermitinae), pp. 501-522 in Zootaxa 4109 (5) on pages 508-510, DOI: 10.11646/zootaxa.4109.5.1, http://zenodo.org/record/26054
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