We quantify the luminosity contribution of active galactic nuclei (AGNs) to the 12 m, mid-infrared (MIR; 5-38 m), and total IR (5-1000 m) emission in the local AGNs detected in the all-sky 70 month ...Swift/Burst Alert Telescope (BAT) ultrahard X-ray survey. We decompose the IR spectral energy distributions (SEDs) of 587 objects into the AGN and starburst components using templates for an AGN torus and a star-forming galaxy. This enables us to recover the emission from the AGN torus including the low-luminosity end, down to , which typically has significant host galaxy contamination. The sample demonstrates that the luminosity contribution of the AGN to the 12 m, the MIR, and the total IR bands is an increasing function of the 14-150 keV luminosity. We also find that for the most extreme cases, the IR pure-AGN emission from the torus can extend up to 90 m. The total IR AGN luminosity obtained through the IR SED decomposition enables us to estimate the fraction of the sky obscured by dust, i.e., the dust covering factor. We demonstrate that the median dust covering factor is always smaller than the median X-ray obscuration fraction above an AGN bolometric luminosity of . Considering that the X-ray obscuration fraction is equivalent to the covering factor coming from both the dust and gas, this indicates that an additional neutral gas component, along with the dusty torus, is responsible for the absorption of X-ray emission.
Abstract
Near- and mid-infrared interferometers have resolved the dusty parsec-scale obscurer (torus) around nearby active galactic nuclei (AGNs). With the arrival of extremely large single-aperture ...telescopes, the emission morphology will soon be resolvable unambiguously, without modeling directly the underlying brightness distribution probed by interferometers today. Simulations must instead deliver the projected 2D brightness distribution as a result of radiative transfer through a 3D distribution of dusty matter around the AGN. We employ such physically motivated 3D dust distributions in tori around AGNs to compute 2D images of the emergent thermal emission, using C
lumpy
, a dust radiative transfer code for clumpy media. We demonstrate that C
lumpy
models can exhibit morphologies with significant polar elongation in the mid-infrared (i.e., the emission extends perpendicular to the dust distribution) on scales of several parsecs, in line with observations in several nearby AGNs. We characterize the emission and cloud distribution morphologies. The observed emission from near- to mid-infrared wavelengths generally does not trace the bulk of the cloud distribution. The elongation of the emission is sensitive to the torus opening angle or scale height. For cloud distributions with a flat radial profile, polar extended emission is realized only at wavelengths shorter than ∼18
μ
m, and shorter than ∼5
μ
m for steep profiles. We make the full results available through H
ypercat
, a large hypercube of resolved AGN torus brightness maps computed with C
lumpy
. H
ypercat
also comprises software to process and analyze such large data cubes and provides tools to simulate observations with various current and future telescopes.
Abstract
We present 0.″4 resolution imaging polarimetry at 8.7, 10.3, and 12.5
μ
m, obtained with CanariCam at the Gran Telescopio Canarias, of the central 0.11 pc × 0.28 pc (4.″2 × 10.″8) region of ...W51 IRS2. The polarization, as high as ∼14%, arises from silicate particles aligned by the interstellar magnetic field (
B
-field). We separate, or unfold, the polarization of each sightline into emission and absorption components, from which we infer the morphologies of the corresponding projected
B
-fields that thread the emitting- and foreground-absorbing regions. We conclude that the projected
B
-field in the foreground material is part of the larger-scale ambient field. The morphology of the projected
B
-field in the mid-infrared (mid-IR) emitting region spanning the cometary H
ii
region W51 IRS2W is similar to that in the absorbing region. Elsewhere, the two
B
-fields differ significantly with no clear relationship between them. The
B
-field across the W51 IRS2W cometary core appears to be an integral part of a champagne outflow of gas originating in the core and dominating the energetics there. The bipolar outflow, W51north jet, that appears to originate at or near SMA1/N1 coincides almost exactly with a clearly demarcated north–south swath of lower polarization. While speculative, comparison of mid-IR and submillimeter polarimetry on two different scales may support a picture in which SMA1/N1 plays a major role in the
B
-field structure across W51 IRS2.
Abstract
Background
Screening for depression and anxiety disorders has been proposed in prison populations but little is known about caseness thresholds on commonly used self-report measures in ...relation to core symptoms, risk factors and symptom patterns.
Method
A cross-sectional prevalence survey measured depression and anxiety caseness (threshold scores
>
10 and
>
15 on PHQ-9 and GAD-7 and diagnostic algorithm on PHQ-9) in 1205 male prisoners aged 35–74 years eligible for an NHS Healthcheck from six English prisons. Caseness scores were compared with the presence or absence of daily core symptoms of depression and generalised anxiety disorder (GAD), demographic, prison and cardiovascular risk factors. Cluster analysis was applied to PHQ-9 and GAD-7 items in prisoners scoring
>
10 on PHQ-9.
Results
453(37.6%) and 249(20.7%) prisoners scored
>
10 and
>
15 respectively on PHQ-9; 216 (17.9%) had a depressive episode on the PHQ-9 algorithm; 378(31.4%) and 217(18.0%) scored
>
10 and
>
15 on GAD-7 respectively. Daily core items for depression were scored in 232(56.2%) and 139(74.3%) prisoners reaching
>
10 and
>
15 respectively on PHQ-9; daily core anxiety items in 282(74.9%) and 179(96.3%) reaching
>
10 and
>
15 on GAD-7. Young age, prison and previous high alcohol intake were associated with
>
15 on the PHQ-9. Cluster analysis showed a cluster with core symptoms of depression, slowness, restlessness, suicidality, poor concentration, irritability or fear. Altered appetite, poor sleep, lack of energy, guilt or worthlessness belonged to other clusters and may not be indicative of depression.
Conclusions
In male prisoners
>
35 years, a score of
>
10 on the PHQ-9 over diagnoses depressive episodes but a score of > 10 on the GAD-7 may detect cases of GAD more efficiently. Further research utilising standardised psychiatric interviews is required to determine whether the diagnostic algorithm, a higher cut-off on the PHQ-9 or the profile of symptoms on the PHQ-9 and GAD-7 used singly or in combination may be used to screen depressive episodes efficiently in prisoners.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
IntroductionHalf of all deaths in custody are due to natural causes, the most common being cardiovascular disease (CVD). National Health Service Healthchecks should be available to all eligible ...prisoners; it is not clear who receives them. Mental health issues are common in prisoners and may affect how healthcare interventions should be delivered. Current policy is to offer Healthchecks to those serving over 2 years in prison.Objectives, methods, setting and designAn observational cross-sectional survey in six male prisons in England between September 2017 and January 2019 in prisoners aged 35–74 to identify who was eligible for a Healthcheck and compare CVD risk data with those that were not, and factors associated with uptake.Outcome measuresCharacteristics of those accepting a Healthcheck were compared with those declining. Assessments of anxiety and depression were compared with CVD risk factors.Results1207 prisoners completed a Healthcheck. 21.8% of prisoners were ineligible due to existing comorbidities. 76.4% of those invited took up a Healthcheck, and of those, 12.1% were found to have new significant CVD comorbidity. CVD risk was similar to community levels but this population was 10 years younger. Definite case-level depression or anxiety was present in 20.7% and 18.0%, respectively, of participants. An association was found between ethnicity and those invited (p=0.023, φ=0.1) and accepting (p=0.008, φ=0.1) a Healthcheck. 9.7% of prisoners serving less than 2 years had CVD risk scores of 10% or more, and had similar CVD risk profiles but much higher levels of anxiety (p<0.001, φ=0.2) or depression (p=0.009, φ=0.2) than those serving 2 years or more.ConclusionCardiovascular risk was comparable with community rates and in some prisons, much higher. Rates of anxiety and depression were high. The national policy for selecting prisoners for Healthchecks may leave many high-risk prisoners without appropriate cardiovascular preventative assessments.
The relationship between public transport use and acquisition of acute respiratory infection (ARI) is not well understood but potentially important during epidemics and pandemics.
A case-control ...study performed during the 2008/09 influenza season. Cases (n = 72) consulted a General Practitioner with ARI, and controls with another non-respiratory acute condition (n = 66). Data were obtained on bus or tram usage in the five days preceding illness onset (cases) or the five days before consultation (controls) alongside demographic details. Multiple logistic regression modelling was used to investigate the association between bus or tram use and ARI, adjusting for potential confounders.
Recent bus or tram use within five days of symptom onset was associated with an almost six-fold increased risk of consulting for ARI (adjusted OR = 5.94 95% CI 1.33-26.5). The risk of ARI appeared to be modified according to the degree of habitual bus and tram use, but this was not statistically significant (1-3 times/week: adjusted OR = 0.54 (95% CI 0.15-1.95; >3 times/week: 0.37 (95% CI 0.13-1.06).
We found a statistically significant association between ARI and bus or tram use in the five days before symptom onset. The risk appeared greatest among occasional bus or tram users, but this trend was not statistically significant. However, these data are plausible in relation to the greater likelihood of developing protective antibodies to common respiratory viruses if repeatedly exposed. The findings have differing implications for the control of seasonal acute respiratory infections and for pandemic influenza.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The Luminous Infrared Galaxy NGC 1614 hosts a prominent circumnuclear ring of star formation. However, the nature of the dominant emitting mechanism in its central ~100 pc is still under debate. We ...present sub-arcsecond angular resolution radio, mid-infrared, Pa alpha , optical, and X-ray observations of NGC 1614, aimed at studying in detail both the circumnuclear ring and the nuclear region. The 8.4 GHz continuum emission traced by the Very Large Array and the Gemini/T-ReCS 8.7 mu m emission, as well as the Pa alpha line emission, show remarkable morphological similarities within the star-forming ring, suggesting that the underlying emission mechanisms are tightly related. We used a Hubble Space Telescope/NICMOS Pa alpha map of similar resolution to our radio maps to disentangle the thermal free-free and non-thermal synchrotron radio emission, from which we obtained the intrinsic synchrotron power law for each individual region within the central kiloparsec of NGC 1614. The radio ring surrounds a relatively faint, steep-spectrum source at the very center of the galaxy, suggesting that the central source is not powered by an active galactic nucleus (AGN), but rather by a compact (r lap 90 pc) starburst (SB). Chandra X-ray data also show that the central kiloparsec region is dominated by SB activity, without requiring the existence of an AGN. We also used publicly available infrared data to model-fit the spectral energy distribution of both the SB ring and a putative AGN in NGC 1614. In summary, we conclude that there is no need to invoke an AGN to explain the observed bolometric properties of the galaxy.
We present a high spatial (diffraction-limited) resolution ({approx}0.''3) mid-infrared (MIR) spectroscopic study of the nuclei and star-forming regions of four local luminous infrared galaxies ...(LIRGs) using T-ReCS on the Gemini South telescope. We investigate the spatial variations of the features seen in the N-band spectra of LIRGs on scales of {approx}100 pc, which allow us to resolve their nuclear regions and separate the active galactic nucleus (AGN) emission from that of the star formation (SF). We compare (qualitatively and quantitatively) our Gemini T-ReCS nuclear and integrated spectra of LIRGs with those obtained with Spitzer IRS. Star-forming regions and AGNs show distinct features in the MIR spectra, and we spatially separate these, which is not possible using the Spitzer data. The 9.7 {mu}m silicate absorption feature is weaker in the nuclei of the LIRGs than in the surrounding regions. This is probably due to the either clumpy or compact environment of the central AGN or young, nuclear starburst. We find that the Ne II12.81 {mu}m luminosity surface density is tightly and directly correlated with that of Paalpha for the LIRG star-forming regions (slope of 1.00 +- 0.02). Although the 11.3 {mu}m PAH feature shows also a trend with Paalpha, this is not common for all the regions and the slope is significantly lower. We also find that the Ne II12.81 {mu}m/Paalpha ratio does not depend on the Paalpha equivalent width (EW), i.e., on the age of the ionizing stellar populations, suggesting that, on the scales probed here, the Ne II12.81 {mu}m emission line is a good tracer of the SF activity in LIRGs. On the other hand, the 11.3 {mu}m PAH/Paalpha ratio increases for smaller values of the Paalpha EW (increasing ages), indicating that the 11.3 {mu}m PAH feature can also be excited by older stars than those responsible for the Paalpha emission. Finally, more data are needed in order to address the different physical processes (age of the stellar populations, hardness and intensity of the radiation field, mass of the star-forming regions) affecting the energetics of the polycyclic aromatic hydrocarbon features in a statistical way. Additional high spatial resolution observations are essential to investigating the SF in local LIRGs at the smallest scales and determining ultimately whether they share the same physical properties as high-z LIRGs, ULIRGs, and submillimiter galaxies and therefore belong to the same galaxy population.
We present high spatial resolution mid-IR images of the nuclear region of NGC 5128 (Centaurus A). Images were obtained at 8.8 mum, N band (10.4 mum), and 18.3 mum using the mid-IR imager/spectrometer ...T-ReCS on Gemini South. These images show a bright unresolved core surrounded by low-level extended emission. We place an upper limit to the size of the unresolved nucleus of 3.2 pc (0.19 super(image )) at 8.8 mum and 3.5 pc (0.21 super(image )) at 18.3 mum at the level of the FWHM. The most likely source of nuclear mid-IR emission is from a dusty torus and possibly a dusty narrow-line region with some contribution from synchrotron emission associated with the jet as well as relatively minor starburst activity. Clumpy tori models are presented which predict the mid-IR size of this torus to be no larger than 0.05 super(image ) (0.85 pc). Surrounding the nucleus is extensive low-level mid-IR emission. This paper presents to date the highest spatial resolution mid-IR images of this extended near nuclear structure, previously observed by ISO and Spitzer. Much of the emission is coincident with Pa alpha sources seen by HST implying emission from star-forming areas; however, evidence for jet-induced star formation, synchrotron emission from the jet, a nuclear bar/ring, and an extended dusty narrow emission line region is also discussed.
CanariCam Mid-infrared Drift Scanning Torres-Quijano, Amílcar R.; Packham, Christopher; Acosta, Sergio Fernandez
Publications of the Astronomical Society of the Pacific,
11/2021, Letnik:
133, Številka:
1029
Journal Article
Recenzirano
Ground-based mid-infrared (MIR) astronomical observations require the removal of the fast time variable components of (a) sky/background variation and (b) array background. Typically, this has been ...achieved through oscillating the telescope’s secondary mirror a few times a second, a process termed “chopping.” However, chopping reduces on-object photon collection time, imposes stringent demands on the secondary mirror, requires nodding of the telescope to remove the radiative offset imprinted by the chopping, and relies on an often-fixed chop-frequency regardless of the sky conditions in the actual observations. In the 30 m telescope era, secondary mirror chopping is impracticable. However, if the sky and background are sufficiently stable, drift scanning holds the promise to remove the necessity of chopping. In this paper, we report our encouraging drift scanning results using the CanariCam MIR instrument on the 10.4 m Gran Telescopio Canarias and the implications to future instruments and experiments.
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