1,931 research outputs found
Searching for high-redshift centimeter-wave continuum, line and maser emission using the Square Kilometer Array
We discuss the detection of redshifted line and continuum emission at radio
wavelengths using a Square Kilometer Array (SKA), specifically from
low-excitation rotational molecular line transitions of CO and HCN (molecular
lines), the recombination radiation from atomic transitions in almost-ionized
hydrogen (radio recombination lines; RRLs), OH and water maser lines, as well
as from synchrotron and free-free continuum radiation and HI 21-cm line
radiation. The detection of radio lines with the SKA offers the prospect to
determine the redshifts and thus exact luminosities for some of the most
distant and optically faint star-forming galaxies and active galactic nuclei
(AGN), even those galaxies that are either deeply enshrouded in interstellar
dust or shining prior to the end of reionization. Moreover, it provides an
opportunity to study the astrophysical conditions and resolved morphologies of
the most active regions in galaxies during the most active phase of star
formation at redshift z~2. A sufficiently powerful and adaptable SKA correlator
will enable wide-field three-dimensional redshift surveys at chosen specific
high redshifts, and will allow new probes of the evolution of large-scale
structure (LSS) in the distribution of galaxies. The detection of molecular
line radiation favours pushing the operating frequencies of SKA up to at least
26 GHz, and ideally to 40 GHz, while very high redshift maser emissions
requires access to about 100 MHz. To search for LSS the widest possible
instantaneous field of view would be advantageous.Comment: 12 pages, 2 figures. To appear in "Science with the Square Kilometer
Array," eds. C. Carilli and S. Rawlings, New Astronomy Reviews (Elsevier:
Amsterdam
A SCUBA Scanmap of the HDF: Measuring the bright end of the sub-mm source counts
Using the 850 micron SCUBA camera on the JCMT and a scanning technique
different from other sub-mm surveys, we have obtained a 125 square arcminute
map centered on the Hubble Deep Field. The one-sigma sensitivity to point
sources is roughly 3 mJy and thus our map probes the brighter end of the sub-mm
source counts. We find 6 sources with a flux greater than about 12 mJy (>4
sigma) and, after a careful accounting of incompleteness and flux bias,
estimate the integrated density of bright sources N(>12 mJy)= 164 (+77/-58) per
square degree (68 per cent confidence bounds).Comment: 5 pages, 2 figures, Accepted for publication in MNRA
âI Now Pronounce You Husband and Sonâ: Confronting the Need to Amend Adult Adoption Codes to Facilitate Same-Sex Marriage
The Acute Effect of Pilates Exercise on Lower Extremity Maximal Strength
International Journal of Exercise Science 9(3): 283-290, 2016. In recent years, the effects of chronic core training on athletic performance have been examined with mixed results; however, the acute effects of core training on athletic performance variables have yet to be examined. Therefore, the purpose of this study was to determine the relationship between an acute bout of core training and lower extremity maximal strength. Seventeen healthy males (weight 90.1 ± 17.2 kg; height 176.7 ± 11.2 cm; age 20.9 ± 1.3 years) performed maximal deadlift assessments following 2 testing conditions. A general cardiovascular warm-up was used as the control condition, and a mat-based Pilates warm-up was used as the core training condition. Statistical significance was set at p \u3c 0.05. Results from a paired-samples t-test showed that the average maximal strength achieved in the Pilates condition (168.6 ± 33.0kg) was significantly higher compared to the Control condition (161.4 ± 31.9kg). These results indicate that an acute bout of core training does have a significant effect on lower extremity maximal strength. Therefore, it may be beneficial to perform core activation exercises, such as Pilates, as part of a warm-up to activate core muscles directly preceding a lower extremity strength exercise
Pasts and pagan practices: moving beyond Stonehenge
Theorizing the past is not restricted to archaeology and interpretations of 'past' both influence and are themselves constituted within politicized understandings of self, community and in certain instances, spirituality. 'The past in the imagination of the present' is appropriated, variously, to give meaning to the present or to justify actions and interpret experiences. Summer solstice at Stonehenge, with an estimated 21,000 celebrants in 2005, is only the most publicized appropriation (by pagans and other adherents of alternative spirituality and partying) of a 'sacred site'; and conflicts and negotiations occurring throughout Britain are represented in popular and academic presentations of this 'icon of Britishness'. This paper presents work from the Sacred Sites, Contested Rites/Rights Project (http://www.sacredsites.org.uk) project, a collaboration of archaeology and anthropology informed by pagan and alternative approaches and standpoints investigating and theorizing discourse and practice of heritage management and pagan site users. Whether in negotiations around the Stonehenge solstice access or in dealing with numerous other sites, boundaries between groups or discourses are not clearly drawn - discursive communities merge and re-emerge. But clearly 'past' and 'site' are increasingly important within today's Britain, even as television archaeology increases its following, and pagan numbers continue to grow.</p
Lensing-Induced Structure of Submillimeter Sources: Implications for the Microwave Background
We consider the effect of lensing by galaxy clusters on the angular
distribution of submillimeter wavelength objects. While lensing does not change
the total flux and number counts of submillimeter sources, it can affect the
number counts and fluxes of flux-limited samples. Therefore imposing a flux cut
on point sources not only reduces the overall Poisson noise, but imprints the
correlations between lensing clusters on the unresolved flux distribution.
Using a simple model, we quantify the lensing anisotropy induced in
flux-limited samples and compare this to Poisson noise. We find that while the
level of induced anisotropies on the scale of the cluster angular correlation
length is comparable to Poisson noise for a slowly evolving cluster model, it
is negligible for more realistic models of cluster evolution. Thus the removal
of point sources is not expected to induce measurable structure in the
microwave or far-infrared backgrounds.Comment: 22 pages, 9 figures, accepted to Astrophysical Journa
The Herschel Lensing Survey (HLS): Overview
The Herschel Lensing Survey (HLS) will conduct deep PACS and SPIRE imaging of âŒ40 massive clusters of galaxies. The strong gravitational lensing power of these clusters will enable us to penetrate through the confusion noise, which sets the ultimate limit on our ability to probe the
Universe with Herschel. Here we present an overview of our survey and a summary of the major results from our science demonstration phase (SDP) observations of the Bullet cluster (z = 0.297). The SDP data are rich and allow us to study not only the background high-redshift galaxies
(e.g., strongly lensed and distorted galaxies at z = 2.8 and 3.2) but also the properties of cluster-member galaxies. Our preliminary analysis shows a great diversity of far-infrared/submillimeter spectral energy distributions (SEDs), indicating that we have much to learn with Herschel about the properties of galaxy SEDs. We have also detected the Sunyaev-Zelâdovich (SZ) effect increment with the SPIRE data. The success of this SDP program demonstrates the great potential of the Herschel Lensing Survey to produce exciting results in a variety of science areas
The far-infrared/submillimeter properties of galaxies located behind the Bullet cluster
The Herschel Lensing Survey (HLS) takes advantage of gravitational lensing by massive galaxy clusters to sample a population of high-redshift galaxies which are too faint to be detected above the confusion limit of current far-infrared/submillimeter telescopes. Measurements from 100â500 ÎŒm bracket the peaks of the far-infrared spectral energy distributions of these galaxies, characterizing their infrared luminosities and star formation rates. We introduce initial results from our science demonstration phase observations, directed toward the Bullet cluster (1E0657-56). By combining our observations with LABOCA 870 ÎŒm and AzTEC 1.1 mm data we fully constrain the spectral energy distributions of 19 MIPS 24 ÎŒm-selected galaxies which are located behind the cluster. We find that their colors are best fit using templates based on local galaxies with systematically lower infrared luminosities. This suggests that our sources are not like local ultra-luminous infrared galaxies in which vigorous star formation is contained in a compact highly dust-obscured region. Instead, they appear to be scaled up versions of lower luminosity local galaxies with star formation occurring on larger physical scales
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