1,382 research outputs found
An Infrared Comparison of Type-1 and Type-2 Quasars
We model the optical to far-infrared SEDs of a sample of six type-1 and six
type-2 quasars selected in the mid-infrared. The objects in our sample are
matched in mid-IR luminosity and selected based on their Spitzer IRAC colors.
We obtained new targeted Spitzer IRS and MIPS observations and used archival
photometry to examine the optical to far-IR SEDs. We investigate whether the
observed differences between samples are consistent with orientation-based
unification schemes. The type-1 objects show significant emission at 3 micron.
They do not show strong PAH emission and have less far-IR emission on average
when compared to the type-2 objects. The SEDs of the type-2 objects show a wide
assortment of silicate features, ranging from weak emission to deep silicate
absorption. Some also show strong PAH features. In comparison, silicate is only
seen in emission in the type-1 objects. This is consistent with some of the
type-2s being reddened by a foreground screen of cooler dust, perhaps in the
host galaxy itself. We investigate the AGN contribution to the far-IR emission
and find it to be significant. We also estimate the star formation rate for
each of the objects by integrating the modeled far-IR flux and compare this
with the SFR found from PAH emission. We find the type-2 quasars have a higher
average SFR than the type-1 quasars based on both methods, though this could be
due to differences in bolometric luminosities of the objects. While we find
pronounced differences between the two types of objects, none of them are
inconsistent with orientation-based unification schemes.Comment: Accepted for publication in Ap
Creating Accessible Websites: Developing a Fire Safety Website for Teenagers Who Are Deaf or Hard of Hearing
This study used three research phases to create an effective fire safety website for deaf teenagers. Participants were students in grades 7-12 from the Oklahoma School for the Deaf. First, 50 students responded to a questionnaire measuring their fire safety knowledge and interests along with their internet use and preferences. For the second phase, 50 students evaluated nine of the current fire safety sites via guided worksheets, and I performed a content analysis of the same nine sites. The third phase, with a stratified selection of 20 students, involved testing the new fire safety site through think-aloud interviews, half of which were conducted via Instant Messaging software to determine whether IM is a feasible tool for usability studies. Deaf teenagers have unique fire safety information needs and internet preferences. Many were unaware of specialized smoke alarms, and they wanted more information about careers for deaf people in the fire service. Of the nine sites tested, none contained information customized to helping a deaf teenager plan effectively for fire emergencies, and many of the sites violated the accessibility guidelines outlined by the World Wide Web Consortium, especially as they used audio features without captions. Six of the websites used vocabulary levels well above the recommended fourth grade reading level for deaf teenagers, and eight sites were too juvenile in tone to appeal to this audience. Echoing the design and navigation aspects of Yahoo and MySpace, the new fire safety website scored well above the other websites tested and received positive feedback from the students. An overwhelming majority of students found the site's words and pictures easy to understand and relevant to their needs, and all the students said they would recommend it to their friends. IM also proved a useful tool for usability studies because the chat transcript shows the students' natural search terms and language structure. But when using IM, researchers must be prepared to rephrase questions and to decipher responses written in text message and TTY codes. Finally, a list of recommended fire safety vocabulary is included as part of the study's conclusions.English Departmen
Searching For Transiting Circumbinary Planets in CoRoT and Ground-Based Data Using CB-BLS
Aims. We search for transiting circumbinary (CB) planets around eclipsing
binaries (EBs).
Methods. CB-BLS is a recently-introduced algorithm for the detection of
transiting CB planets around EBs.We describe progress in search sensitivity,
generality and capability of CB-BLS, and detection tests of CB-BLS on simulated
data. We also describe an analytical approach for the determination of CB-BLS
detection limits, and a method for the correct detrending of
intrinsically-variable stars.
Results. We present some blind-tests with simulated planets injected to real
CoRoT data. The presented upgrades to CB-BLS allowed it to detect all the blind
tests successfully, and these detections were in line with the detection limits
analysis. We also correctly detrend bright eclipsing binaries from observations
by the TrES planet search, and present some of the first results of applying
CB-BLS to multiple real light curves from a wide-field survey.
Conclusions. CB-BLS is now mature enough for its application to real data,
and the presented processing scheme will serve as the template for our future
applications of CB-BLS to data from wide-field surveys such as CoRoT. Being
able to put constraints even on non-detection will help to determine the
correct frequency of CB planets, contributing to the understanding of planet
formation in general. Still, searching for transiting CB planets is still a
learning experience, similarly to the state of transiting planets around single
stars only a few years ago. The recent rapid progress in this front, coupled
with the exquisite quality of space-based photometry, allows to realistically
expect that if transiting CB planets exist - then they will soon be found.Comment: A&A accepted. Presented at the 1st CoRoT symposium. Note table 3 is
too wide in this version, but omitted data is of minor significance. 10
pages, 10 figures, 3 table
Hyper-Velocity Impact Performance of Foldcore Sandwich Composites
A foldcore is a novel core made from a flat sheet of any material folded into a desired pattern. A foldcore sandwich composite (FSC) provides highly tailorable structural performance over conventional sandwich composites made with honeycomb or synthetic polymer foam cores. Foldcore design can be optimized to accommodate complex shapes and unit cell geometries suitable for protective shielding structures
This work aims to characterize hypervelocity impact (\u3e 2000 m/s, HVI) response and corresponding damage morphologies of carbon fiber reinforced polymer (CFRP) FSCs. A series of normal (0° impact angle) and oblique (45° impact angle) HVI (~3km/s nominal projectile velocity) impact tests were performed on CFRP FSC targets to understand the effects of projectile impact on redirected debris formation, and variable debris cloud expansion. HVI damage in FSC targets were assessed using visual inspection and high-speed imaging analysis. The results from the present study indicate that debris cloud propagation and expansion are strongly influenced by foldcore impact location/angle and open-channel direction. This work serves as a baseline study to understand HVI response of FSC targets and to identify critical FSC design parameters to optimize HVI mitigation performance
The North Ecliptic Pole Wide survey of AKARI: a near- and mid-infrared source catalog
We present a photometric catalog of infrared (IR) sources based on the North
Ecliptic PoleWide field (NEP-Wide) survey of AKARI, which is an infrared space
telescope launched by Japan. The NEP-Wide survey covered 5.4 deg2 area, a
nearly circular shape centered on the North Ecliptic Pole, using nine
photometric filter-bands from 2 - 25 {\mu}m of the Infrared Camera (IRC).
Extensive efforts were made to reduce possible false objects due to cosmic ray
hits, multiplexer bleeding phenomena around bright sources, and other
artifacts. The number of detected sources varied depending on the filter band:
with about 109,000 sources being cataloged in the near-IR bands at 2 - 5
{\mu}m, about 20,000 sources in the shorter parts of the mid-IR bands between 7
- 11 {\mu}m, and about 16,000 sources in the longer parts of the mid-IR bands,
with \sim 4,000 sources at 24 {\mu}m. The estimated 5? detection limits are
approximately 21 magnitude (mag) in the 2 - 5 {\mu}m bands, 19.5 - 19 mag in
the 7 - 11 {\mu}m, and 18.8 - 18.5 mag in the 15 - 24 {\mu}m bands in the AB
magnitude scale. The completenesses for those bands were evaluated as a
function of magnitude: the 50% completeness limits are about 19.8 mag at 3
{\mu}m, 18.6 mag at 9 {\mu}m, and 18 mag at 18 {\mu}m band, respectively. To
construct a reliable source catalog, all of the detected sources were examined
by matching them with those in other wavelength data, including optical and
ground-based near-IR bands. The final band-merged catalog contains about
114,800 sources detected in the IRC filter bands. The properties of the sources
are presented in terms of the distributions in various color-color diagrams.Comment: Accepted for publication in A&A, 23 pages, 27 figure
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