The traditional picture of post-starburst galaxies as dust- and gas-poor merger remnants, rapidly transitioning to quiescence, has been recently challenged. Unexpected detections of a significant ...interstellar medium (ISM) in many post-starburst galaxies raise important questions. Are they truly quiescent, and if so, what mechanisms inhibit further star formation? What processes dominate their ISM energetics? We present an infrared spectroscopic and photometric survey of 33 E+A post-starbursts selected by the Sloan Digital Sky Survey, aimed at resolving these questions. We find compact, warm dust reservoirs with high PAH abundances and total gas and dust masses significantly higher than expected from stellar recycling alone. Both polycyclic aromatic hydrocarbon (PAH)/total infrared (TIR) and dust-to-burst stellar mass ratios are seen to decrease with post-burst age, indicative of the accumulating effects of dust destruction and an incipient transition to hot, early-type ISM properties. Their infrared spectral properties are unique, with dominant PAH emission, very weak nebular lines, unusually strong H2 rotational emission, and deep C ii deficits. There is substantial scatter among star formation rate (SFR) indicators, and both PAH and TIR luminosities provide overestimates. Even as potential upper limits, all tracers show that the SFR has typically experienced a decline of more than two orders of magnitude since the starburst and that the SFR is considerably lower than expected given both their stellar masses and molecular gas densities. These results paint a coherent picture of systems in which star formation was, indeed, rapidly truncated, but in which the ISM was not completely expelled, and is instead supported against collapse by latent or continued injection of turbulent or mechanical heating. The resulting aging burst populations provide a "high-soft" radiation field that seemingly dominates the E+A galaxies' unusual ISM energetics.
Abstract
Taking advantage of the unprecedented combination of sensitivity and angular resolution afforded by the Herschel Space Observatory at far-infrared and submillimetre wavelengths, we aim to ...characterize the physical properties of cold dust within nearby galaxies, as well as the associated uncertainties, namely the robustness of the parameters we derive using different modified blackbody models. For a pilot subsample of the KINGFISH (Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel) key programme, we perform two-temperature fits of the Spitzer and Herschel photometric data (from 24 to 500 μm), with a warm and a cold component, both globally and in each resolution element. We compare the results obtained from different analysis strategies. At global scale, we observe a range of values of the modified blackbody fit parameters βc (0.8-2.5) and T
c (19.1-25.1 K). We compute maps of our modelling parameters with βc fixed or treated as a free parameter to test the robustness of the temperature and dust surface density maps we deduce. When the emissivity is fixed, we observe steeper temperature gradients as a function of radius than when it is allowed to vary. When the emissivity is fitted as a free parameter, barred galaxies tend to have uniform fitted emissivities. Gathering the parameters obtained in each resolution element in a T
c-βc diagram underlines an anticorrelation between the two parameters. It remains difficult to assess whether the dominant effect is the physics of dust grains, noise, or mixing along the line of sight and in the beam. We finally observe in both cases that the dust column density peaks in central regions of galaxies and bar-ends (coinciding with molecular gas density enhancements usually found in these locations). We also quantify how the total dust mass varies with our assumptions about the emissivity index as well as the influence of the wavelength coverage used in the fits. We show that modified blackbody fits using a shallow emissivity (β < 2.0) lead to significantly lower dust masses compared to the β < 2.0 case, with dust masses lower by up to 50 per cent if βc = 1.5, for instance. The working resolution affects our total dust mass estimates: masses increase from global fits to spatially resolved fits.
With the growing number of heterogeneous resource-constrained devices connected to the Internet, it becomes increasingly challenging to secure the privacy and protection of data. Strong but efficient ...cryptography solutions must be employed to deal with this problem, along with methods to standardize secure communications between these devices. The PRISEC module of the UbiPri middleware has this goal. In this work, we present the performance of the AES (Advanced Encryption Standard), RC6 (Rivest Cipher 6), Twofish, SPECK128, LEA, and ChaCha20-Poly1305 algorithms in Internet of Things (IoT) devices, measuring their execution times, throughput, and power consumption, with the main goal of determining which symmetric key ciphers are best to be applied in PRISEC. We verify that ChaCha20-Poly1305 is a very good option for resource constrained devices, along with the lightweight block ciphers SPECK128 and LEA.
ABSTRACT The H i and CO components of the interstellar medium (ISM) are usually used to derive the dynamical mass of nearby galaxies. Both components become too faint to be used as a tracer in ...observations of high-redshift galaxies. In those cases, the 158 m line of atomic carbon (C ii) may be the only way to derive . As the distribution and kinematics of the ISM tracer affects the determination of , it is important to quantify the relative distributions of H i, CO, and C ii. H i and CO are well-characterized observationally, however, for C ii only very few measurements exist. Here we compare observations of CO, H i, and C ii emission of a sample of nearby galaxies, drawn from the HERACLES, THINGS, and KINGFISH surveys. We find that within R25, the average C ii exponential radial profile is slightly shallower than that of the CO, but much steeper than the H i distribution. This is also reflected in the integrated spectrum ("global profile"), where the C ii spectrum looks more like that of the CO than that of the H i. For one galaxy, a spectrally resolved comparison of integrated spectra was possible; other comparisons were limited by the intrinsic line-widths of the galaxies and the coarse velocity resolution of the C ii data. Using high-spectral-resolution SOFIA C ii data of a number of star forming regions in two nearby galaxies, we find that their C ii linewidths agree better with those of the CO than the H i. As the radial extent of a given ISM tracer is a key input in deriving from spatially unresolved data, we conclude that the relevant length-scale to use in determining based on C ii data, is that of the well-characterized CO distribution. This length scale is similar to that of the optical disk.
The physical state of interstellar gas and dust is dependent on the processes which heat and cool this medium. To probe heating and cooling of the interstellar medium over a large range of infrared ...surface brightness, on sub-kiloparsec scales, we employ line maps of CII 158 mu m, OI 63 mu m, and NII 122 mu m in NGC 1097 and NGC 4559, obtained with the Photodetector Array Camera & Spectrometer on board Herschel. We matched new observations to existing Spitzer Infrared Spectrograph data that trace the total emission of polycyclic aromatic hydrocarbons (PAHs). We confirm at small scales in these galaxies that the canonical measure of photoelectric heating efficiency, (CII + OI)/TIR, decreases as the far-infrared (far-IR) color, nufunctionof sub(nu)(70 mu m) nufunctionof sub(nu)(100 mu m), increases. In contrast, the ratio of far-IR cooling to total PAH emission, (CII + OI)/PAH, is a near constant ~6% over a wide range of far-IR color, 0.5 < nufunctionof sub(nu)(70 mu m) nufunctionof sub(nu)(100 mu m) <, ~0.95. In the warmest regions, where nufunctionof sub(nu)(70 mu m) nufunctionof sub(nu)(100 mu m) > ~0.95, the ratio (CII + OII)/PAH drops rapidly to 4%. We derived representative values of the local ultraviolet radiation density, G sub(0), and the gas density, n sub(H), by comparing our observations to models of photodissociation regions. The ratio G sub(0)/n sub(H), derived from fine-structure lines, is found to correlate with the mean dust-weighted starlight intensity, left angle bracketUright angle bracket, derived from models of the IR spectral energy distribution. Emission from regions that exhibit a line deficit is characterized by an intense radiation field, indicating that small grains are susceptible to ionization effects. We note that there is a shift in the 7.7/11.3 mu m PAH ratio in regions that exhibit a deficit in (CII + OI)/PAH, suggesting that small grains are ionized in these environments.
New far-infrared and submillimeter photometry from the Herschel Space Observatory is presented for 61 nearby galaxies from the Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel ...(KINGFISH) sample. The spatially integrated fluxes are largely consistent with expectations based on Spitzer far-infrared photometry and extrapolations to longer wavelengths using popular dust emission models. Dwarf irregular galaxies are notable exceptions, as already noted by other authors, as their 500 mu m emission shows evidence for a submillimeter excess. In addition, the fraction of dust heating attributed to intense radiation fields associated with photodissociation regions is found to be (21 + or - 4)% larger when Herschel data are included in the analysis. Dust masses obtained from the dust emission models of Draine & Li are found to be on average nearly a factor of two higher than those based on single-temperature modified blackbodies, as single blackbody curves do not capture the full range of dust temperatures inherent to any galaxy. The discrepancy is largest for galaxies exhibiting the coolest far-infrared colors.
Employing data collected during the first 25 months of observations by the Fermi-LAT, we describe and subsequently seek to model the very high energy (>300 MeV) emission from the central few parsecs ...of our Galaxy. We analyze the morphological, spectral, and temporal characteristics of the central source, 1FGL J1745.6--2900. The data show a clear, statistically significant signal at energies above 10 GeV, where the Fermi-LAT has angular resolution comparable to that of HESS at TeV energies. This makes a meaningful joint analysis of the data possible. Our analysis of the Fermi data (alone) does not uncover any statistically significant variability of 1FGL J1745.6--2900 at GeV energies on the month timescale. Using the combination of Fermi data on 1FGL J1745.6--2900 and HESS data on the coincident, TeV source HESS J1745--290, we show that the spectrum of the central gamma-ray source is inflected with a relatively steep spectral region matching between the flatter spectrum found at both low and high energies. We model the gamma-ray production in the inner 10 pc of the Galaxy and examine cosmic ray (CR) proton propagation scenarios that reproduce the observed spectrum of the central source. We show that a model that instantiates a transition from diffusive propagation of the CR protons at low energy to almost rectilinear propagation at high energies can explain well the spectral phenomenology. We find considerable degeneracy between different parameter choices which will only be broken with the addition of morphological information that gamma-ray telescopes cannot deliver given current angular resolution limits. We argue that a future analysis performed in combination with higher-resolution radio continuum data holds out the promise of breaking this degeneracy.
Context:Heterozygous mutations in the Aggrecan gene (ACAN) cause autosomal dominant short stature with bone age (BA) acceleration, premature growth cessation and minor skeletal ...abnormalities.Objective:Characterize the phenotypic spectrum, associated conditions and response to growth-promoting therapies.Design:Retrospective international cohort study.Patients:Information from 103 individuals (57 female, 46 male) from 20 families with confirmed heterozygous ACAN mutations were included.Methods:Families with autosomal dominant short stature and heterozygous ACAN mutations were identified and confirmed using whole-exome sequencing, targeted next generation sequencing, and/or Sanger sequencing. Clinical information was collected from medical records.Results:Identified ACAN variants showed perfect co-segregation with phenotype. Adult individuals had mildly disproportionate short stature (median height: -2.8 SDS, range: -5.9 to -0.9) and histories of early growth cessation. The condition was frequently associated with early-onset osteoarthritis (12 families) and intervertebral disc disease (9 families). There was no apparent genotype-phenotype correlation between type of ACAN mutation and presence of joint complaints. During childhood, height was less affected (median height: -2.0 SDS, range: -4.2 to -0.6). In contrast to most children with short stature, the majority of children had advanced BA (BA – CA, median: +1.3y; range +0.0 to +3.7y) reflecting a reduction in remaining growth potential. Nineteen individuals had received GH with some evidence of increased growth velocity.Conclusions:Heterozygous ACAN mutations result in a phenotypic spectrum ranging from mild and proportionate short stature to a mild skeletal dysplasia with disproportionate short stature and brachydactyly. In several of the families, affected individuals developed early-onset osteoarthritis and degenerative disc disease requiring intervention, suggesting dysfunction of articular cartilage and intervertebral disc cartilage. Additional studies are needed to determine the optimal treatment strategy for these patients.
We investigate the far infrared (IR) spectrum of NGC 1266, a S0 galaxy that contains a massive reservoir of highly excited molecular gas. Using the Herschel Fourier Transform Spectrometer, we detect ...the super(12)CO ladder up to J = (13-12), CI and NII lines, and also strong water lines more characteristic of UltraLuminous IR Galaxies (ULIRGs). The super(12)CO line emission is modeled with a combination of a low-velocity C-shock and a photodissociation region. Shocks are required to produce the H sub(2)O and most of the high-J CO emission. Despite having an IR luminosity 30 times less than a typical ULIRG, the spectral characteristics and physical conditions of the interstellar medium of NGC 1266 closely resemble those of ULIRGs, which often harbor strong shocks and large-scale outflows.
Person-first language is taught in most health professions programs and mandated by scholarly journals but is often not practiced by health care practitioners. The disconnection between academia and ...clinical practice is significant. Students and new practitioners are often faced with the challenge of holding to their training or falling in line with the status quo. While the use of person-first language should be the norm in all health care settings, unfortunately, often the opposite is true. The person-first language movement began in 1974. Since that time, the culture of disability has drastically changed. There is greater integration of individuals with a disability and with that integration has come greater understanding and acceptance. Increased community integration has allowed for greater opportunities for advocacy and has also forced a shift in how the community at large views people with a disability. This shift in how individuals with a disability are viewed has resulted in a change in language. A change in semantics is not enough. Health professions educators need to ensure that students understand why this change has taken place and why it is essential. The power language can have not only on patient care but also on patient outcomes is profound and should be understood by both educators and practitioners alike. The purpose of this paper is to discuss the factors surrounding person-first language and its integration into health care, including the difference between what is taught and mandated, and what is practiced.
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![COMPARING [C ii], H i, AND ...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0004-6256_1538-3881/small "COMPARING [C ii], H i, AND CO DYNAMICS OF NEARBY GALAXIES")
