51 research outputs found
Absorption Troughs of Lyman Alpha Emitters in HETDEX
The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is designed to
detect and measure the redshifts of more than one million Ly emitting
galaxies (LAEs) between . In addition to its cosmological
measurements, these data enable studies of Ly spectral profiles and the
underlying radiative transfer. Using the roughly half a million LAEs in the
HETDEX Data Release 3, we stack various subsets to obtain the typical
Ly profile for the epoch and to understand their physical
properties. We find clear absorption wings around Ly emission, which
extend km both redward and blueward of the
central line. Using far-UV spectra of nearby () LAEs in the
CLASSY treasury and optical/near-IR spectra of LAEs in the
MUSE-Wide survey, we observe absorption profiles in both redshift regimes.
Dividing the sample by volume density shows that the troughs increase in higher
density regions. This trend suggests that the depth of the absorption is
dependent on the local density of objects near the LAE, a geometry that is
similar to damped Lyman- systems. Simple simulations of Ly
radiative transfer can produce similar troughs due to absorption of light from
background sources by HI gas surrounding the LAEs.Comment: 15 pages, 10 figures, accepted for publication in The Astrophysical
Journa
Absorption Troughs of Lyα Emitters in HETDEX
The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is designed to detect and measure the redshifts of more than 1 million Lyα emitting galaxies (LAEs) 1.88 < z < 3.52. In addition to its cosmological measurements, these data enable studies of Lyα spectral profiles and the underlying radiative transfer. Using the roughly half a million LAEs in the HETDEX Data Release 3, we stack various subsets to obtain the typical Lyα profile for the z ∼ 2-3 epoch and to understand their physical properties. We find clear absorption wings around Lyα emission, which extend ∼2000 km s−1 both redward and blueward of the central line. Using far-UV spectra of nearby (0.002 < z < 0.182) LAEs in the COS Legacy Archive Spectroscopic Survey treasury and optical/near-IR spectra of 2.8 < z < 6.7 LAEs in the Multi Unit Spectroscopic-Wide survey, we observe absorption profiles in both redshift regimes. Dividing the sample by volume density shows that the troughs increase in higher-density regions. This trend suggests that the depth of the absorption is dependent on the local density of objects near the LAE, a geometry that is similar to damped Lyα systems. Simple simulations of Lyα radiative transfer can produce similar troughs due to absorption of light from background sources by H i gas surrounding the LAEs
HETDEX Public Source Catalog 1 -- Stacking 50K Lyman Alpha Emitters
We describe the ensemble properties of the Lyman Alpha
Emitters (LAEs) found in the HETDEX survey's first public data release, HETDEX
Public Source Catalog 1 (Mentuch Cooper et al. 2023). Stacking the
low-resolution ( 800) spectra greatly increases the signal-to-noise
ratio, revealing spectral features otherwise hidden by noise, and we show that
the stacked spectrum is representative of an average member of the set. The
flux limited, Ly signal-to-noise ratio restricted stack of 50K HETDEX
LAEs shows the ensemble biweight ``average" LAE to be a blue (UV
continuum slope and E(B-V) ), moderately bright
(M) star forming galaxy with strong Ly
emission (log 42.8 and (Ly)
114\AA), and potentially significant leakage of ionizing radiation. The
restframe UV light is dominated by a young, metal poor stellar population with
an average age 5-15 Myr and metallicity of 0.2-0.3 Z.Comment: 17 pages, 11 figures, 2 data files (ApJ Accepted
HETDEX Public Source Catalog 1: 220K Sources Including Over 50K Lyman Alpha Emitters from an Untargeted Wide-area Spectroscopic Survey
We present the first publicly released catalog of sources obtained from the
Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). HETDEX is an integral
field spectroscopic survey designed to measure the Hubble expansion parameter
and angular diameter distance at 1.88<z<3.52 by using the spatial distribution
of more than a million Ly-alpha-emitting galaxies over a total target area of
540 deg^2. The catalog comes from contiguous fiber spectra coverage of 25 deg^2
of sky from January 2017 through June 2020, where object detection is performed
through two complementary detection methods: one designed to search for line
emission and the other a search for continuum emission. The HETDEX public
release catalog is dominated by emission-line galaxies and includes 51,863
Ly{\alpha}-emitting galaxy (LAE) identifications and 123,891 OII-emitting
galaxies at z<0.5. Also included in the catalog are 37,916 stars, 5274
low-redshift (z<0.5) galaxies without emission lines, and 4976 active galactic
nuclei. The catalog provides sky coordinates, redshifts, line identifications,
classification information, line fluxes, OII and Ly-alpha line luminosities
where applicable, and spectra for all identified sources processed by the
HETDEX detection pipeline. Extensive testing demonstrates that HETDEX redshifts
agree to within deltaz < 0.02, 96.1% of the time to those in external
spectroscopic catalogs. We measure the photometric counterpart fraction in deep
ancillary Hyper Suprime-Cam imaging and find that only 55.5% of the LAE sample
has an r-band continuum counterpart down to a limiting magnitude of r~26.2 mag
(AB) indicating that an LAE search of similar sensitivity with photometric
pre-selection would miss nearly half of the HETDEX LAE catalog sample. Data
access and details about the catalog can be found online at http://hetdex.org/.Comment: 38 pages, 20 figures. Data access and details about the catalog can
be found online at http://hetdex.org/. A copy of the catalogs presented in
this work (Version 3.2) is available to download at Zenodo
doi:10.5281/zenodo.744850
A meta-analysis of individual participant data reveals an association between circulating levels of IGF-I and prostate cancer risk
The role of insulin-like growth factors (IGF) in prostate cancer development is not fully understood. To investigate the association between circulating concentrations of IGFs (IGF-I, IGF-II, IGFBP-1, IGFBP-2, and IGFBP-3) and prostate cancer risk, we pooled individual participant data from 17 prospective and two cross-sectional studies, including up to 10,554 prostate cancer cases and 13,618 control participants. Conditional logistic regression was used to estimate the ORs for prostate cancer based on the study-specific fifth of each analyte. Overall, IGF-I, IGF-II, IGFBP-2, and IGFBP-3 concentrations were positively associated with prostate cancer risk (Ptrend all ≤ 0.005), and IGFBP-1 was inversely associated weakly with risk (Ptrend = 0.05). However, heterogeneity between the prospective and cross-sectional studies was evident (Pheterogeneity = 0.03), unless the analyses were restricted to prospective studies (with the exception of IGF-II, Pheterogeneity = 0.02). For prospective studies, the OR for men in the highest versus the lowest fifth of each analyte was 1.29 (95% confidence interval, 1.16-1.43) for IGF-I, 0.81 (0.68-0.96) for IGFBP-1, and 1.25 (1.12-1.40) for IGFBP-3. These associations did not differ significantly by time-to-diagnosis or tumor stage or grade. Aftermutual adjustment for each of the other analytes, only IGF-I remained associated with risk. Our collaborative study represents the largest pooled analysis of the relationship between prostate cancer risk and circulating concentrations of IGF-I, providing strong evidence that IGF-I is highly likely to be involved in prostate cancer development.</p
Impact of Traumatic Sports Injury on an Athlete’s Psychological Wellbeing, Adherence to Sport and Athletic Identity
Introduction: Sports injuries can affect athletes across all ages, sexes, and levels of competition. The mental aspect of acute sports injury is often overlooked by coaches, trainers, and medical professionals. This study investigated if and how an acute traumatic sports injury affects an athlete’s psychological well-being, adherence to sport, and athletic identity. Methods: The study consisted of surveys sent to former or current athletes over 18 with one or more athletic injuries. The Qualtrics surveys were anonymous, and participants consented to the study within the survey. Results: There were 101 total participants (20.2% response rate) with an average age of 36. All reported one or more acute athletic injuries throughout their athletic careers. Specific survey sets were compared against each other using a variable correlation analysis (p - value < 0.05) and via Pearson’s Correlation.Conclusion: The results indicated that injury impacts the lives of athletes most significantly on the field and can harm their performance based on their perception of the severity of the injury. However, this decline in performance and decrease in confidence does not correlate to an athlete’s desire to leave their sport or how they identify as being an athlete. 
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