29 research outputs found
The Relationship between Level of Religiosity and Past Suicidal Ideation in Gay Males
Gay males have higher than average rates of suicidal ideation, which has been attributed in part to the pressure to conform to societal religious norms. Using the theoretical frameworks of Durkheim and of Pescosolido and Georgianna, the purpose of this quantitative study was to explore the role of religiosity as a factor of suicidal ideation in gay males. In this study, 113 gay males completed an online survey regarding their level of religiosity as measured by the Religious Background and Behaviors Questionnaire, past suicidal ideation as measured by the Suicidal Ideation Measure, and certain predictor variables, including being out to family members, family being supportive, age, religious affiliation (current and during childhood), ethnicity, and population of town during childhood. Regression analyses found no direct statistical significance between level of religiosity and suicidal ideation. There was a predictive relationship, however, between level of family support, level of religiosity, and suicidal ideation. These findings support the Pescosolido and Georgianna theory that belongingness reduces suicidal ideation. The implications for positive social change include the need for mental health professionals to highlight the importance of positive support for gay males as a potential buffer to suicidal ideation
Focal Plate Structure Alignment of the Dark Energy Spectroscopic Instrument
The Dark Energy Spectroscopic Instrument (DESI) is under construction to
measure the expansion history of the universe using the Baryon Acoustic
Oscillation (BAO) technique. The spectra of 35 million galaxies and quasars
over will be measured during the life of the experiment.
A new prime focus corrector for the KPNO Mayall telescope will deliver light to
5000 robotically positioned optic fibres. The fibres in turn feed ten broadband
spectrographs. Proper alignment of focal plate structure, mainly consisting of
a focal plate ring (FPR) and ten focal plate petals (FPP), is crucial in
ensuring minimal loss of light in the focal plane. A coordinate measurement
machine (CMM) metrology-based approach to alignment requires comprehensive
characterisation of critical dimensions of the petals and the ring, all of
which were 100% inspected. The metrology data not only served for quality
assurance (QA), but also, with careful modelling of geometric transformations,
informed the initial choice of integration accessories such as gauge blocks,
pads, and shims. The integrated focal plate structure was inspected again on a
CMM, and each petal was adjusted according to the updated focal plate metrology
data until all datums were extremely close to nominal positions and optical
throughput nearly reached the theoretically best possible value. This paper
presents our metrology and alignment methodology and complete results for
twelve official DESI petals. The as-aligned, total RMS optical throughput for
6168 positioner holes of twelve production petals was indirectly measured to be
, well above the 99.5% project requirement. The successful
alignment fully demonstrated the wealth of data, reproducibility, and
micron-level precision made available by our CMM metrology-based approach.Comment: 17 pages, 10 figures, 3 table
Dark Energy Spectroscopic Instrument (DESI) Fiber Positioner Production
The Dark Energy Spectroscopic Instrument (DESI) is under construction to
measure the expansion history of the Universe using the Baryon Acoustic
Oscillation technique. The spectra of 35 million galaxies and quasars over
14000 sq deg will be measured during the life of the experiment. A new prime
focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber
optic positioners. The fibers in turn feed ten broad-band spectrographs. We
will describe the production and manufacturing processes developed for the 5000
fiber positioner robots mounted on the focal plane of the Mayall telescope.Comment: SPIE 201
Long-term follow-up observations of extreme coronal line emitting galaxies
We present new spectroscopic and photometric follow-up observations of the
known sample of extreme coronal line emitting galaxies (ECLEs) identified in
the Sloan Digital Sky Survey (SDSS). With these new data, observations of the
ECLE sample now span a period of two decades following their initial SDSS
detections. We confirm the nonrecurrence of the iron coronal line signatures in
five of the seven objects, further supporting their identification as the
transient light echoes of tidal disruption events (TDEs). Photometric
observations of these objects in optical bands show little overall evolution.
In contrast, mid-infrared (MIR) observations show ongoing long-term declines.
The remaining two objects had been classified as active galactic nuclei (AGN)
with unusually strong coronal lines rather than being TDE related, given the
persistence of the coronal lines in earlier follow-up spectra. We confirm this
classification, with our spectra continuing to show the presence of strong,
unchanged coronal-line features and AGN-like MIR colours and behaviour. We have
constructed spectral templates of both subtypes of ECLE to aid in
distinguishing the likely origin of newly discovered ECLEs. We highlight the
need for higher cadence, and more rapid, follow-up observations of such objects
to better constrain their properties and evolution. We also discuss the
relationships between ECLEs, TDEs, and other identified transients having
significant MIR variability.Comment: Submitted to MNRAS. 33 pages, 15 figure
Mitigating the noise of DESI mocks using analytic control variates
In order to address fundamental questions related to the expansion history of
the Universe and its primordial nature with the next generation of galaxy
experiments, we need to model reliably large-scale structure observables such
as the correlation function and the power spectrum. Cosmological -body
simulations provide a reference through which we can test our models, but their
output suffers from sample variance on large scales. Fortunately, this is the
regime where accurate analytic approximations exist. To reduce the variance,
which is key to making optimal use of these simulations, we can leverage the
accuracy and precision of such analytic descriptions using Control Variates
(CV). We apply two control variate formulations to mock catalogs generated in
anticipation of upcoming data from the Dark Energy Spectroscopic Instrument
(DESI) to test the robustness of its analysis pipeline. Our CV-reduced
measurements, of the power spectrum and correlation function, both pre- and
post-reconstruction, offer a factor of 5-10 improvement in the measurement
error compared with the raw measurements from the DESI mock catalogs. We
explore the relevant properties of the galaxy samples that dictate this
reduction and comment on the improvements we find on some of the derived
quantities relevant to Baryon Acoustic Oscillation (BAO) analysis. We also
provide an optimized package for computing the power spectra and other
two-point statistics of an arbitrary galaxy catalog as well as a pipeline for
obtaining CV-reduced measurements on any of the AbacusSummit cubic box outputs.
We make our scripts, notebooks, and benchmark tests against existing software
publicly available and report a speed improvement of a factor of 10 for a
grid size of compared with .Comment: 15 pages, 9 figures, public package (for power spectrum and control
variates estimation
Long-term follow-up observations of extreme coronal line emitting galaxies
We present new spectroscopic and photometric follow-up observations of the known sample of extreme coronal line-emitting galaxies (ECLEs) identified in the Sloan Digital Sky Survey (SDSS). With these new data, observations of the ECLE sample now span a period of two decades following their initial SDSS detections. We confirm the non-recurrence of the iron coronal line signatures in five of the seven objects, further supporting their identification as the transient light echoes of tidal disruption events (TDEs). Photometric observations of these objects in optical bands show little overall evolution. In contrast, mid-infrared (MIR) observations show ongoing long-term declines consistent with power-law decay. The remaining two objects had been classified as active galactic nuclei (AGNs) with unusually strong coronal lines rather than being TDE related, given the persistence of the coronal lines in earlier follow-up spectra. We confirm this classification, with our spectra continuing to show the presence of strong, unchanged coronal line features and AGN-like MIR colours and behaviour. We have constructed spectral templates of both subtypes of ECLE to aid in distinguishing the likely origin of newly discovered ECLEs. We highlight the need for higher cadence, and more rapid, follow-up observations of such objects to better constrain their properties and evolution. We also discuss the relationships between ECLEs, TDEs, and other identified transients having significant MIR variability
Performance of the Dark Energy Spectroscopic Instrument (DESI) focal plane
International audienceThe recently commissioned Dark Energy Spectroscopic Instrument (DESI) will measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 35 million galaxies and quasars over 14,000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope delivers light to 5,000 fiber optic positioners which in turn feed ten broad-band spectro- graphs. The DESI focal plane subsystem contains the fiber optic positioners and guide and focus cameras, which enable the alignment of fibers with astronomical targets. This paper describes the performance of the installed instrument
Mitigating the noise of DESI mocks using analytic control variates
International audienceIn order to address fundamental questions related to the expansion history of the Universe and its primordial nature with the next generation of galaxy experiments, we need to model reliably large-scale structure observables such as the correlation function and the power spectrum. Cosmological -body simulations provide a reference through which we can test our models, but their output suffers from sample variance on large scales. Fortunately, this is the regime where accurate analytic approximations exist. To reduce the variance, which is key to making optimal use of these simulations, we can leverage the accuracy and precision of such analytic descriptions using Control Variates (CV). We apply two control variate formulations to mock catalogs generated in anticipation of upcoming data from the Dark Energy Spectroscopic Instrument (DESI) to test the robustness of its analysis pipeline. Our CV-reduced measurements, of the power spectrum and correlation function, both pre- and post-reconstruction, offer a factor of 5-10 improvement in the measurement error compared with the raw measurements from the DESI mock catalogs. We explore the relevant properties of the galaxy samples that dictate this reduction and comment on the improvements we find on some of the derived quantities relevant to Baryon Acoustic Oscillation (BAO) analysis. We also provide an optimized package for computing the power spectra and other two-point statistics of an arbitrary galaxy catalog as well as a pipeline for obtaining CV-reduced measurements on any of the AbacusSummit cubic box outputs. We make our scripts, notebooks, and benchmark tests against existing software publicly available and report a speed improvement of a factor of 10 for a grid size of compared with