1,370,518 research outputs found
The Herschel Stripe 82 Survey (HerS): maps and early catalog
We present the first set of maps and band-merged catalog from the Herschel Stripe 82 Survey (HerS). Observations at 250, 350, and 500μm were taken with the Spectral and Photometric Imaging Receiver instrument aboard the Herschel Space Observatory. HerS covers 79deg 2 along the SDSS Stripe 82 to an average depth of 13.0, 12.9, and 14.8mJybeam −1 (including confusion) at 250, 350, and 500μm, respectively. HerS was designed to measure correlations with external tracers of the dark matter density field—either point-like (i.e., galaxies selected from radio to X-ray) or extended (i.e., clusters and gravitational lensing)—in order to measure the bias and redshift distribution of intensities of infrared-emitting dusty star-forming galaxies and active galactic nuclei. By locating HerS in Stripe 82, we maximize the overlap with available and upcoming cosmological surveys. The band-merged catalog contains 3.3 × 10 4 sources detected at a significance of ?3σ (including confusion noise). The maps and catalog are available at http://www.astro.caltech.edu/hers/
The early cartography of Renfrewshire to 1864
With their detail of past geographical distributions, early maps can be valuable documents in assisting many fields of local study. Much of Scotland's distinctive cartography was channelled into the brief period between the publication of the Blaeu atlas in 1654 and the Ordnance Survey six- and twenty-five inch sheets which first appeared in the 1840s and 1850s. Despite a scarcity of maps, particularly prior to the mid-eighteenth century, Scotland has a uniquely rich cartographic history and the work of early map-makers has contributed to placing "Scotland among the best mapped countries in the world". Unfortunately, this archive of Scotland's past remains largely untapped and study of the maps themselves has been noticeably limited, particularly in the field of cartobibliography (or listing what exists), where few areas have been investigated in detail. This work attempts to fill the gap for Renfrewshire and its burghs of Paisley, Greenock and Port Glasgow. The selected maps are mostly topographical, illustrating the county either as a separate unit or as a major part of a larger area. Maps which cover the whole of Scotland are not discussed, thereby excluding the one-inch Ordnance Survey sheets. Also omitted are large scale plans of estates or significant portions of the county. As the intention is to be as comprehensive as possible, both printed and manuscript maps are listed. Relatively few thematic maps were published before the middle of the nineteenth century but those relating solely to the county are again discussed
Contour-map encoding of shape for early vision
Contour maps provide a general method for recognizing 2-D shapes. All but blank images give rise to such maps, and people are good at recognizing objects and shapes from them. The maps are encoded easily in long feature vectors that are suitable for recognition by an associative memory. These properties of contour maps suggest a role for them in early visual perception. The prevalence of direction sensitive neurons in the visual cortex of mammals supports this view
Identification of microtubule-associated proteins in the centrosome, spindle, and kinetochore of the early Drosophila embryo.
We have developed affinity chromatography methods for the isolation of microtubule-associated proteins (MAPs) from soluble cytoplasmic extracts and have used them to analyze the cytoskeleton of the early Drosophila embryo. More than 50 Drosophila embryo proteins bind to microtubule affinity columns. To begin to characterize these proteins, we have generated individual mouse polyclonal antibodies that specifically recognize 24 of them. As judged by immunofluorescence, some of the antigens localize to the mitotic spindle in the early Drosophila embryo, while others are present in centrosomes, kinetochores, subsets of microtubules, or a combination of these structures. Since 20 of the 24 antibodies stain microtubule structures, it is likely that most of the proteins that bind to our columns are associated with microtubules in vivo. Very few MAPS seem to be identically localized in the cell, indicating that the microtubule cytoskeleton is remarkably complex
Dust lanes causing structure in the extended narrow line region of early-type Seyfert galaxies
We construct near-infrared to visible broad band NICMOS/WFPC color maps for 4
early-type Seyfert galaxies with S-shaped or one-sided ionization cones. We
find that dust lanes are near or connected to many of the features seen in the
[OIII] and H+[NII] line emission maps. This suggests that much of the
structure of line emission in these ionization cones is determined by the
distribution of ambient dense galactic gas. Spiral arms, dust lanes caused by
bars, or gaseous warps provide dense gas which when illuminated by a conical
beam of ultraviolet photons can result in the complicated line emission
morphologies observed.Comment: accepted by Ap
Two-Dimensional Line Strength Maps in Three Well-studied Early-Type Galaxies
Integral field spectroscopy has been obtained for the nuclear regions of 3
large, well-studied, early-type galaxies. From these spectra we have obtained
line strength maps for about 20 absorption lines, mostly belonging to the Lick
system. An extensive comparison with multi-lenslet spectroscopy shows that
accurate kinematic maps can be obtained, and also reproducible line strength
maps. Comparison with long-slit spectroscopy also produces good agreement. We
show that Mg is enhanced with respect to Fe in the inner disk of one of the
three galaxies studied, the Sombrero. [Mg/Fe] there is larger than in the rest
of the bulge. The large values of Mg/Fe in the central disk are consistent with
the centres of other early-type galaxies, and not with large disks, like the
disk of our Galaxy, where [Mg/Fe] is approximately 0. We confirm with this
observation a recent result of Worthey (1998) that Mg/Fe is determined by the
central kinetic energy, or escape velocity, of the stars, only, and not by the
formation time scale of the stars. A stellar population analysis using the
models of Vazdekis et al. (1996) shows that our observed H gamma agrees well
with what is predicted based on the other lines. Using the line strength of the
Ca II IR triplet as an indicator of the abundance of Ca, we find that Ca
follows Fe, and not Mg, in these galaxies. This is peculiar, given the fact
that Ca is an alpha-element. Finally, by combining the results of this paper
with those of Vazdekis et al. (1997) we find that the line strength gradients
in the three galaxies are primarily caused by variations in metallicity.Comment: 23 pages, Latex, includes mn.sty, accepted for publication in Monthly
Notices of the Royal Astronomical Societ
Young starless cores embedded in the magnetically dominated Pipe Nebula
The Pipe Nebula is a massive, nearby dark molecular cloud with a low
star-formation efficiency which makes it a good laboratory to study the very
early stages of the star formation process. The Pipe Nebula is largely
filamentary, and appears to be threaded by a uniform magnetic field at scales
of few parsecs, perpendicular to its main axis. The field is only locally
perturbed in a few regions, such as the only active cluster forming core B59.
The aim of this study is to investigate primordial conditions in low-mass
pre-stellar cores and how they relate to the local magnetic field in the cloud.
We used the IRAM 30-m telescope to carry out a continuum and molecular survey
at 3 and 1 mm of early- and late-time molecules toward four selected starless
cores inside the Pipe Nebula. We found that the dust continuum emission maps
trace better the densest regions than previous 2MASS extinction maps, while
2MASS extinction maps trace better the diffuse gas. The properties of the cores
derived from dust emission show average radii of ~0.09 pc, densities of
~1.3x10^5 cm^-3, and core masses of ~2.5 M_sun. Our results confirm that the
Pipe Nebula starless cores studied are in a very early evolutionary stage, and
present a very young chemistry with different properties that allow us to
propose an evolutionary sequence. All of the cores present early-time molecular
emission, with CS detections toward all the sample. Two of them, Cores 40 and
109, present strong late-time molecular emission. There seems to be a
correlation between the chemical evolutionary stage of the cores and the local
magnetic properties that suggests that the evolution of the cores is ruled by a
local competition between the magnetic energy and other mechanisms, such as
turbulence.Comment: Accepted for publication in ApJ. 15 pages, 5 figures, 9 table
Exploring notions of genre in 'academic literacies' and 'writing across the curriculum': approaches across countries and contexts
The SIGET IV panel on genre in Writing Across the Curriculum (WAC) and “academic literacies” (ACLITS) has set rolling a discussion of the similarities and differences in the two traditions, the former originating in the US in the early 1970s, the latter originating in England in the early 1990s. This paper maps out some elements of each in relation to the other and to genre, which we hope will set in motion further discussions and cross-fertilization
Polar wander analysis from paleomagnetic data
Utilizing marine magnetic anomalies and paleomagnetic pole positions, paleogeographic maps were constructed for three time intervals back to the Early Cretaceous. From the maps lithospheric plate motions were calculated and these global displacement fields were analyzed to determine best-fitting rigid rotations, which then could be ascribed to true polar wander. The values so obtained are no larger than a few degrees and are within the magnitude of the uncertainties involved
The Structures of Distant Galaxies V: The Evolution of Galaxy Structure in Stellar Mass at z < 1
Galaxy structure and morphology is nearly always studied using the light
originating from stars, however ideally one is interested in measuring
structure using the stellar mass distribution. Not only does stellar mass trace
out the underlying distribution of matter, it also minimises the effects of
star formation and dust on the appearance and structure of a galaxy. We present
in this paper a study of the stellar mass distributions and structures of
galaxies at z<1 as found within the GOODS fields. We use pixel by pixel
K-corrections to construct stellar mass and mass-to-light ratio maps of 560
galaxies of known morphology at magnitudes z_{850}<24. We measure structural
and size parameters using these stellar mass maps, as well as on ACS BViz band
imaging. This includes investigating the structural CAS-Gini-M_{20} parameters
and half-light radius for each galaxy. We compare structural parameters and
half-light radii in the ACS z_{850}-band and stellar mass maps, finding no
systematic bias introduced by measuring galaxy sizes in z_{850}. We furthermore
investigate relations between structural parameters in the ACS BViz bands and
stellar mass maps, and compare our result to previous morphological studies.
Combinations of various parameters in stellar mass generally reveal clear
separations between early and late type morphologies, but cannot easily
distinguish between star formation and dynamically disturbed systems. We also
show that while ellipticals and early-type spirals have fairly constant CAS
values at z<1 we find a tendency for late-type spiral and peculiar
morphological types to have a higher A(M_{*}) at higher redshift. We argue that
this, and the large fraction of peculiars that appear spiral-like in stellar
mass maps, are possible evidence for either an active bulge formation in some
late-type disks at z<1 or the presence of minor merger events.Comment: 27 pages, MNRAS in pres
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