86 research outputs found
The Ontology of Scholar-Administrators: Empirical Inferences from Five Senior Administrators Who Published
The purpose of this study was to fill a gap in existing literature on scholar-administrators and understand the lived experience of scholar-administrators who published. Using an interpretative phenomenological approach to extract themes from detailed case studies of five senior academic administrators who have published, the researchers’ empirical inferences from the five detailed case histories reveal the challenges and rewards of producing scholarship as a scholar-administrator. Their findings show that the administrators were more connected to the people within and outside the university, their own field of practice, and with the university. The impact of scholarship on scholar-administrators goes beyond publications. Continuation of being a scholar-practitioner has significant impact on networking scope of administrators keeping the educational entities they lead abreast of environmental trends to adapt to. Future research should replicate our study to increase the generalizability of its findings
Advancing the Next Generation of Higher Education Scholars: An Examination of One Doctoral Classroom
Course content in graduate school is especially important in terms of helping students make progress toward a doctorate. However, content is merely one aspect of developing successful students. This article highlights the value of creating an affirming learning environment by discussing one graduate class on Qualitative Policy Research. The majority of student participants were graduate students of color. The authors discuss the pedagogical approaches guiding this course and outline ways in which the instructor served to create safe spaces that invited as well as validated diverse perspectives and made the research process transparent. These efforts resulted in the production of high quality research used as pilot studies for successful dissertation defenses, accepted presentations at scholarly conferences, and published articles in peer-reviewed journals. Throughout this article, suggestions for replicating a similar course environment are discussed
CLASH-X: A Comparison of Lensing and X-ray Techniques for Measuring the Mass Profiles of Galaxy Clusters
We present profiles of temperature (Tx), gas mass, and hydrostatic mass
estimated from new and archival X-ray observations of CLASH clusters. We
compare measurements derived from XMM and Chandra observations with one another
and compare both to gravitational lensing mass profiles derived with CLASH HST
and ground-based lensing data. Radial profiles of Chandra and XMM electron
density and enclosed gas mass are nearly identical, indicating that differences
in hydrostatic masses inferred from X-ray observations arise from differences
in Tx measurements. Encouragingly, cluster Txs are consistent with one another
at ~100-200 kpc radii but XMM Tx systematically decline relative to Chandra Tx
at larger radii. The angular dependence of the discrepancy suggests additional
investigation on systematics such as the XMM point spread function correction,
vignetting and off-axis responses. We present the CLASH-X mass-profile
comparisons in the form of cosmology-independent and redshift-independent
circular-velocity profiles. Ratios of Chandra HSE mass profiles to CLASH
lensing profiles show no obvious radial dependence in the 0.3-0.8 Mpc range.
However, the mean mass biases inferred from the WL and SaWLens data are
different. e.g., the weighted-mean value at 0.5 Mpc is = 0.12 for the WL
comparison and = -0.11 for the SaWLens comparison. The ratios of XMM HSE
mass profiles to CLASH lensing profiles show a pronounced radial dependence in
the 0.3-1.0 Mpc range, with a weighted mean mass bias of value rising to
~0.3 at ~1 Mpc for the WL comparison and of 0.25 for SaWLens comparison.
The enclosed gas mass profiles from both Chandra and XMM rise to a value 1/8
times the total-mass profiles inferred from lensing at 0.5 Mpc and remain
constant outside of that radius, suggesting that [8xMgas] profiles may be an
excellent proxy for total-mass profiles at >0.5 Mpc in massive galaxy clusters.Comment: Accepted to ApJ; 24 pages; scheduled to appear in the Oct 10, 2014
issue. This version corrects the typographical error in the superscripts for
Equation (2) to include the square of (r/r_core). The correct version of this
equation was used in the analysi
Reality Hackers: The Next Wave of Media Revolutionaries
Just as the printing press gave rise to the nation-state, emerging technologies are reshaping collective identities and challenging our understanding of what it means to be human.
Should citizens have the right to be truly anonymous on-line? Should we be concerned about the fact that so many people are choosing to migrate to virtual worlds? Are injectible microscopic radio-frequency ID chips a blessing or a curse? Is the use of cognitive enhancing nootropics a human right or an unforgivable transgression? Should genomic data about human beings be hidden away with commercial patents or open-sourced like software? Should hobbyists known as biohackers be allowed to experiment with genetic engineering in their home laboratories?
The time-frame for acting on such questions is relatively short, and these decisions are too important to be left up to a small handful of scientists and policymakers. If democracy is to continue as a viable alternative to technocracy, the average citizen must become more involved in these debates. To borrow a line from the computer visionary Ted Nelson, all of us can -- and must -- understand technology now.
Challenging the popular stereotype of hackers as ciminal sociopaths, reality hackers uphold the basic tenets of what Steven Levy (1984) terms the hacker ethic. These core principles include a commitment to: sharing, openness, decentralization, public access to information, and the use of new technologies to make the world a better place.https://digitalcommons.trinity.edu/mono/1000/thumbnail.jp
PEARLS: Low Stellar Density Galaxies in the El Gordo Cluster Observed with JWST
A full understanding of how unusually large "Ultra Diffuse Galaxies" (UDGs)
fit into our conventional understanding of dwarf galaxies remains elusive,
despite the large number of objects identified locally. A natural extension of
UDG research is the study of similar galaxies at higher redshift to establish
how their properties may evolve over time. However, this has been a challenging
task given how severely systematic effects and cosmological surface brightness
dimming inhibit our ability to study low-surface brightness galaxies at
high-. Here, we present an identification of low stellar surface density
galaxies (LDGs), likely the progenitors of local UDGs, at moderate redshift
with deep near-IR observations of the El Gordo cluster at with JWST.
By stacking 8 NIRCAM filters, we are able to achieve an apparent surface
brightness sensitivity of mag arcsec, faint enough to be
complete to the bright end of the LDG population. Our analysis identifies
significant differences between this population and local UDGs, such as their
color and size distributions, which suggest that UDG progenitors are bluer and
more extended at high- than at . This suggests that multiple
mechanisms are responsible for UDG formation and that prolonged transformation
of cluster dwarfs is not a primary UDG formation mechanism at high-.
Furthermore, we find a slight overabundance of LDGs in El Gordo, and, in
contrast to findings in local clusters, our analysis does not show a deficit of
LDGs in the center of El Gordo, implying that tidal destruction of LDGs is
significant between and .Comment: Resubmitted to ApJ after minor revision
JWST NIRCam Photometry: A Study of Globular Clusters Surrounding Bright Elliptical Galaxy VV 191a at z=0.0513
James Webb Space Telescope NIRCam images have revealed 443 globular cluster
(GC) candidates around the elliptical galaxy VV 191a. NIRCam
broadband observations are made at 0.9-4.5 m using filters F090W, F150W,
F356W, and F444W. Using photometry, the data is analyzed to present
color-magnitude diagrams (CMDs) that suggest a fairly uniform population of
GCs. Color histograms show a unimodal color distribution that is well fit by a
single Gaussian, using color to primarily trace the metallicity. The findings
show the sample's globular cluster luminosity function (GCLF) does not reach
the turnover value and is, therefore, more luminous than what is typically
expected, with an absolute AB magnitude, mag, reaching
within nearly one magnitude of the classical turnover value. We attribute this
to the completeness in the sample. Models show that the mass estimate of the
GCs detected tends to be more massive, reaching upward of . However, the results show that current GC models do not quite align
with the data. We find that the models appear to be bluer than the JWST data in
the reddest (F356W-F444W) filters and redder than the data in the bluest
(F090W-F150W) filters and may need to be revised to improve the modeling of
near-IR colors of old, metal-poor stellar populations.Comment: 11 pages, 7 figure
EPOCHS VII: Discovery of high redshift () AGN candidates in JWST ERO and PEARLS data
We present an analysis of a sample of robust high redshift galaxies selected
photometrically from the `blank' fields of the Prime Extragalactic Areas for
Reionization Science (PEARLS) survey and Early Release Observations (ERO) data
of the James Webb Space Telescope (JWST) with the aim of selecting candidate
high redshift active galactic nuclei (AGN). Sources were identified from the
parent sample using a threefold selection procedure, which includes spectral
energy distribution (SED) fitting to identify sources that are best fitted by
AGN SED templates, a further selection based on the relative performance of AGN
and non-AGN models, and finally morphological fitting to identify compact
sources of emission, resulting in a purity-oriented procedure. Using this
procedure, we identify a sample of nine AGN candidates at , from
which we constrain their physical properties as well as measure a lower bound
on the AGN fraction in this redshift range of \%. As this is an
extreme lower limit due to our focus on purity and our SEDs being calibrated
for unobscured Type 1 AGN, this demonstrates that AGN are perhaps quite common
at this early epoch. The rest-frame UV colors of our candidate objects suggest
that these systems are potentially candidate obese black hole galaxies (OBG),
or AGN with very little galaxy component. We also investigate emission from our
sample sources from fields overlapping with Chandra and VLA surveys, allowing
us to place X-ray and 3 GHz radio detection limits on our candidates. Of note
is a candidate source exhibiting an abrupt morphological shift in
the reddest band as compared to the bluer bands, indicating a potential merger
or an unusually strong outflow.Comment: Submitted to MNRAS, 12 pages, 11 figures, typos correcte
Magellanic System Stars Identified in the SMACS J0723.3-7327 JWST ERO Images
We identify 68 distant stars in JWST/NIRCam ERO images of the field of galaxy
cluster SMACS J0723.3-7327 (SMACS 0723). Given the relatively small
() angular separation between SMACS 0723 and the Large
Magellanic Cloud, it is likely that these stars are associated with the LMC
outskirts or Leading Arm. This is further bolstered by a spectral energy
distribution analysis, which suggests an excess of stars at a physical distance
of kpc, consistent with being associated with or located behind the
Magellanic system. In particular, we find that the overall surface density of
stars brighter than 27.0 mag in the field of SMACS 0723 is 2.3 times that
of stars in a blank field with similar galactic latitude (the North Ecliptic
Pole Time Domain Field), and that the density of stars in the SMACS 0723 field
with SED-derived distances consistent with the Magellanic system is 7.3
times larger than that of the blank field. The candidate stars at these
distances are consistent with a stellar population at the same distance modulus
with [Fe/H] and an age of Gyr. On the assumption that all
of the 68 stars are associated with the LMC, then the stellar density of the
LMC at the location of the SMACS 0723 field is stars kpc,
which helps trace the density of stars in the LMC outskirts.Comment: Submitted to ApJ, comments welcom
PEARLS: A Potentially Isolated Quiescent Dwarf Galaxy with a TRGB Distance of 31 Mpc
A wealth of observations have long suggested that the vast majority of
isolated classical dwarf galaxies (- M) are currently
star-forming. However, recent observations of the large abundance of
"Ultra-Diffuse Galaxies" beyond the reach of previous large spectroscopic
surveys suggest that our understanding of the dwarf galaxy population may be
incomplete. Here we report the serendipitous discovery of an isolated quiescent
dwarf galaxy in the nearby Universe, which was imaged as part of the PEARLS GTO
program. Remarkably, individual red-giant branch stars are visible in this
near-IR imaging, suggesting a distance of Mpc, and a wealth of archival
photometry point to an sSFR of yr. Spectra obtained
with the Lowell Discovery Telescope find a recessional velocity consistent with
the Hubble Flow and km/s separated from the nearest massive galaxy in
SDSS, suggesting that this galaxy was either quenched from internal mechanisms
or had a very high-velocity interaction with a nearby massive galaxy in the
past. This analysis highlights the possibility that many nearby quiescent dwarf
galaxies are waiting to be discovered and that JWST has the potential to
identify them.Comment: Submitted to ApJ Letters. Comments welcome
Are JWST/NIRCam color gradients in the lensed z=2.3 dusty star-forming galaxy El Anzuelo due to central dust attenuation or inside-out galaxy growth?
Gradients in the mass-to-light ratio of distant galaxies impede our ability
to characterize their size and compactness. The long-wavelength filters of
's NIRCam offer a significant step forward. For galaxies at Cosmic Noon
(), this regime corresponds to the rest-frame near-infrared, which is
less biased towards young stars and captures emission from the bulk of a
galaxy's stellar population. We present an initial analysis of an extraordinary
lensed dusty star-forming galaxy (DSFG) at behind the
cluster (), named ("The Fishhook") after its partial
Einstein-ring morphology. The FUV-NIR SED suggests an intrinsic star formation
rate of and dust attenuation , in line with other DSFGs on the star-forming main sequence. We develop a
parametric lens model to reconstruct the source-plane structure of dust imaged
by the Atacama Large Millimeter/submillimeter Array, far-UV to optical light
from , and near-IR imaging with 8 filters of /NIRCam, as part of
the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS)
program. The source-plane half-light radius is remarkably consistent from m, despite a clear color gradient where the inferred galaxy center is
redder than the outskirts. We interpret this to be the result of both a
radially-decreasing gradient in attenuation and substantial spatial offsets
between UV- and IR-emitting components. A spatial decomposition of the SED
reveals modestly suppressed star formation in the inner kiloparsec, which
suggests that we are witnessing the early stages of inside-out quenching.Comment: 29 pages, 11 figures, 5 tables. Accepted for publication in Ap
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