Mid-Infrared Spectral Measures of Star-Formation and AGN Activity in Normal Galaxies

We investigate the use of MIR PAH bands, continuum and emission lines as probes of star-formation and AGN activity in a sample of 100 'normal' and local (z~0.1) emission-line galaxies. The MIR spectra were obtained with the Spitzer Space Telescope Infrared Spectrograph (IRS) as part of the Spitzer-SDSS-GALEX Spectroscopic Survey (SSGSS) which includes multi-wavelength photometry from the UV to the FIR and optical spectroscopy. The continuum and features were extracted using PAHFIT (Smith et al. 2007), a decomposition code which we find to yield PAH equivalent widths up to ~30 times larger than the commonly used spline methods. Despite the lack of extreme objects in our sample (such as strong AGNs, low metallicity galaxies or ULIRGs), we find significant variations in PAH, continuum and emission line properties and systematic trends between these MIR properties and optically derived physical properties such as age, metallicity and radiation field hardness. We revisit the diagnostic diagram relating PAH equivalent widths and [Ne II]12.8micrometers/[O IV]25.9micrometers line ratios and find it to be in much better agreement with the standard optical star-formation/AGN classification than when spline decompositions are used, while also potentially revealing obscured AGNs. The luminosity of individual PAH components, of the continuum, and with poorer statistics, of the neon emission lines and molecular hydrogen lines, are found to be tightly correlated to the total IR luminosity, making individual MIR components good gauges of the total dust emission in SF galaxies. Like the total IR luminosity, these individual components can be used to estimate dust attenuation in the UV and in Halpha lines based on energy balance arguments. We also propose average scaling relations between these components and dust corrected, Halpha derived star-formation rates.Comment: Accepted for publication in Ap

Combining gamma with Alpha and Beta power modulation for enhanced cortical mapping in patients with focal epilepsy

About one third of patients with epilepsy have seizures refractory to the medical treatment. Electrical stimulation mapping (ESM) is the gold standard for the identification of "eloquent" areas prior to resection of epileptogenic tissue. However, it is time-consuming and may cause undesired side effects. Broadband gamma activity (55-200 Hz) recorded with extraoperative electrocorticography (ECoG) during cognitive tasks may be an alternative to ESM but until now has not proven of definitive clinical value. Considering their role in cognition, the alpha (8-12 Hz) and beta (15-25 Hz) bands could further improve the identification of eloquent cortex. We compared gamma, alpha and beta activity, and their combinations for the identification of eloquent cortical areas defined by ESM. Ten patients with intractable focal epilepsy (age: 35.9 ± 9.1 years, range: 22-48, 8 females, 9 right handed) participated in a delayed-match-to-sample task, where syllable sounds were compared to visually presented letters. We used a generalized linear model (GLM) approach to find the optimal weighting of each band for predicting ESM-defined categories and estimated the diagnostic ability by calculating the area under the receiver operating characteristic (ROC) curve. Gamma activity increased more in eloquent than in non-eloquent areas, whereas alpha and beta power decreased more in eloquent areas. Diagnostic ability of each band was close to 0.7 for all bands but depended on multiple factors including the time period of the cognitive task, the location of the electrodes and the patient's degree of attention to the stimulus. We show that diagnostic ability can be increased by 3-5% by combining gamma and alpha and by 7.5-11% when gamma and beta were combined. We then show how ECoG power modulation from cognitive testing can be used to map the probability of eloquence in individual patients and how this probability map can be used in clinical settings to optimize ESM planning. We conclude that the combination of gamma and beta power modulation during cognitive testing can contribute to the identification of eloquent areas prior to ESM in patients with refractory focal epilepsy.info:eu-repo/semantics/publishedVersio

Precise Black Hole Masses From Megamaser Disks: Black Hole-Bulge Relations at Low Mass

The black hole (BH)-bulge correlations have greatly influenced the last decade of effort to understand galaxy evolution. Current knowledge of these correlations is limited predominantly to high BH masses (M_BH> 10^8 M_sun) that can be measured using direct stellar, gas, and maser kinematics. These objects, however, do not represent the demographics of more typical L< L* galaxies. This study transcends prior limitations to probe BHs that are an order of magnitude lower in mass, using BH mass measurements derived from the dynamics of H_2O megamasers in circumnuclear disks. The masers trace the Keplerian rotation of circumnuclear molecular disks starting at radii of a few tenths of a pc from the central BH. Modeling of the rotation curves, presented by Kuo et al. (2010), yields BH masses with exquisite precision. We present stellar velocity dispersion measurements for a sample of nine megamaser disk galaxies based on long-slit observations using the B&C spectrograph on the Dupont telescope and the DIS spectrograph on the 3.5m telescope at Apache Point. We also perform bulge-to-disk decomposition of a subset of five of these galaxies with SDSS imaging. The maser galaxies as a group fall below the M_BH-sigma* relation defined by elliptical galaxies. We show, now with very precise BH mass measurements, that the low-scatter power-law relation between M_BH and sigma* seen in elliptical galaxies is not universal. The elliptical galaxy M_BH-sigma* relation cannot be used to derive the BH mass function at low mass or the zeropoint for active BH masses. The processes (perhaps BH self-regulation or minor merging) that operate at higher mass have not effectively established an M_BH-sigma* relation in this low-mass regime.Comment: 21 pages, 14 figures, accepted for publication in the Astrophysical Journa

Constraining Exoplanet Metallicities and Aerosols with ARIEL: An Independent Study by the Contribution to ARIEL Spectroscopy of Exoplanets (CASE) Team

Launching in 2028, ESA's 0.64 m^2 Atmospheric Remote-sensing Exoplanet Large-survey (ARIEL) survey of ~1000 transiting exoplanets will build on the legacies of NASA's Kepler and Transiting Exoplanet Survey Satellite (TESS), and complement the James Webb Space Telescope (JWST) by placing its high-precision exoplanet observations into a large, statistically significant planetary population context. With continuous 0.5–7.8 μm coverage from both FGS (0.5–0.6, 0.6–0.81, and 0.81–1.1 μm photometry; 1.1–1.95 μm spectroscopy) and AIRS (1.95–7.80 μm spectroscopy), ARIEL will determine atmospheric compositions and probe planetary formation histories during its 3.5 yr mission. NASA's proposed Contribution to ARIEL Spectroscopy of Exoplanets (CASE) would be a subsystem of ARIEL's Fine Guidance Sensor (FGS) instrument consisting of two visible-to-infrared detectors, associated readout electronics, and thermal control hardware. FGS, to be built by the Polish Academy of Sciences Space Research Centre, will provide both fine guiding and visible to near-infrared photometry and spectroscopy, providing powerful diagnostics of atmospheric aerosol contribution and planetary albedo, which play a crucial role in establishing planetary energy balance. The CASE team presents here an independent study of the capabilities of ARIEL to measure exoplanetary metallicities, which probe the conditions of planet formation, and FGS to measure scattering spectral slopes, which indicate if an exoplanet has atmospheric aerosols (clouds and hazes), and geometric albedos, which help establish planetary climate. Our simulations assume that ARIEL's performance will be 1.3× the photon-noise limit. This value is motivated by current transiting exoplanet observations: Spitzer/IRAC and Hubble/WFC3 have empirically achieved 1.15× the photon-noise limit. One could expect similar performance from ARIEL, JWST, and other proposed future missions such as HabEx, LUVOIR, and Origins. Our design reference mission simulations show that ARIEL could measure the mass–metallicity relationship of its 1000-planet single-visit sample to >7.5σ and that FGS could distinguish between clear, cloudy, and hazy skies and constrain an exoplanet's atmospheric aerosol composition to ≳5σ for hundreds of targets, providing statistically transformative science for exoplanet atmospheres

Constraining Exoplanet Metallicities and Aerosols with ARIEL: An Independent Study by the Contribution to ARIEL Spectroscopy of Exoplanets (CASE) Team

Launching in 2028, ESA's 0.64 m^2 Atmospheric Remote-sensing Exoplanet Large-survey (ARIEL) survey of ~1000 transiting exoplanets will build on the legacies of NASA's Kepler and Transiting Exoplanet Survey Satellite (TESS), and complement the James Webb Space Telescope (JWST) by placing its high-precision exoplanet observations into a large, statistically significant planetary population context. With continuous 0.5–7.8 μm coverage from both FGS (0.5–0.6, 0.6–0.81, and 0.81–1.1 μm photometry; 1.1–1.95 μm spectroscopy) and AIRS (1.95–7.80 μm spectroscopy), ARIEL will determine atmospheric compositions and probe planetary formation histories during its 3.5 yr mission. NASA's proposed Contribution to ARIEL Spectroscopy of Exoplanets (CASE) would be a subsystem of ARIEL's Fine Guidance Sensor (FGS) instrument consisting of two visible-to-infrared detectors, associated readout electronics, and thermal control hardware. FGS, to be built by the Polish Academy of Sciences Space Research Centre, will provide both fine guiding and visible to near-infrared photometry and spectroscopy, providing powerful diagnostics of atmospheric aerosol contribution and planetary albedo, which play a crucial role in establishing planetary energy balance. The CASE team presents here an independent study of the capabilities of ARIEL to measure exoplanetary metallicities, which probe the conditions of planet formation, and FGS to measure scattering spectral slopes, which indicate if an exoplanet has atmospheric aerosols (clouds and hazes), and geometric albedos, which help establish planetary climate. Our simulations assume that ARIEL's performance will be 1.3× the photon-noise limit. This value is motivated by current transiting exoplanet observations: Spitzer/IRAC and Hubble/WFC3 have empirically achieved 1.15× the photon-noise limit. One could expect similar performance from ARIEL, JWST, and other proposed future missions such as HabEx, LUVOIR, and Origins. Our design reference mission simulations show that ARIEL could measure the mass–metallicity relationship of its 1000-planet single-visit sample to >7.5σ and that FGS could distinguish between clear, cloudy, and hazy skies and constrain an exoplanet's atmospheric aerosol composition to ≳5σ for hundreds of targets, providing statistically transformative science for exoplanet atmospheres

The James Webb Space Telescope Mission: Optical Telescope Element Design, Development, and Performance

The James Webb Space Telescope (JWST) is a large, infrared space telescope that has recently started its science program which will enable breakthroughs in astrophysics and planetary science. Notably, JWST will provide the very first observations of the earliest luminous objects in the Universe and start a new era of exoplanet atmospheric characterization. This transformative science is enabled by a 6.6 m telescope that is passively cooled with a 5-layer sunshield. The primary mirror is comprised of 18 controllable, low areal density hexagonal segments, that were aligned and phased relative to each other in orbit using innovative image-based wavefront sensing and control algorithms. This revolutionary telescope took more than two decades to develop with a widely distributed team across engineering disciplines. We present an overview of the telescope requirements, architecture, development, superb on-orbit performance, and lessons learned. JWST successfully demonstrates a segmented aperture space telescope and establishes a path to building even larger space telescopes.Comment: accepted by PASP for JWST Overview Special Issue; 34 pages, 25 figure

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb29

Anti-microbial activities of pomegranate rind extracts: enhancement by cupric sulphate against clinical isolates of S. aureus, MRSA and PVL positive CA-MSSA

BACKGROUND: Recently, natural products have been evaluated as sources of antimicrobial agents with efficacies against a variety of micro-organisms. METHODS: This report describes the antimicrobial activities of pomegranate rind extract (PRE) singularly and in combination with cupric sulphate against methicillin-sensitive and -resistant Staphylococcus aureus (MSSA, MRSA respectively), and Panton-Valentine Leukocidin positive community acquired MSSA (PVL positive CA-MSSA). RESULTS: PRE alone showed limited efficacy against MRSA and MSSA strains. Exposure to copper (II) ions alone for 2 hours resulted in moderate activity of between 102 to 103 log10 cfu mL-1 reduction in growth. This was enhanced by the addition of PRE to 104 log10 cfu mL-1 reduction in growth being observed in 80% of the isolates. However, the PVL positive CA-MSSA strains were more sensitive to copper (II) ions which exhibited moderate activities of between 103 log10 cfu mL-1 reduction in growth for 60% of the isolates. CONCLUSION: PRE, in combination with Cu(II) ions, was seen to exhibit moderate antimicrobial effects against clinical isolates of MSSA, MRSA and PVL positive CA-MSSA isolates. The results of this study indicate that further investigation into the active ingredients of natural products, their mode of action and potential synergism with other antimicrobial agents is warranted. This is the first report of the efficacy of pomegranate against clinical PVL positive CA-MSSA isolates

Antimicrobial activities of pomegranate rind extracts: enhancement by addition of metal salts and vitamin C

BACKGROUND: Punica granatum L. or pomegranates, have been reported to have antimicrobial activity against a range of Gram positive and negative bacteria. Pomegranate formulations containing ferrous salts have enhanced although short-term, antibacteriophage activities which are rapidly diminished owing to instability of the ferrous combination. The aim of this study was to determine the antimicrobial activities of combinations of pomegranate rind extracts (PRE) with a range of metals salts with the added stabiliser vitamin C. METHODS: PRE solutions, prepared by blending rind sections with distilled water prior to sterilisation by autoclaving or filtration, were screened with a disc diffusion assay using penicillin G as a control. Suspension assays were used to determine the antimicrobial activities of PRE alone and in combination with salts of the following metals; Fe (II), Cu (II), Mn (II) or Zn (II), and vitamin C, against a panel of microbes following exposure for 30 mins. The test organisms included Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Proteus mirabilis. RESULTS: The screening assay demonstrated that PRE exhibited activity against the Gram positive organisms at 24 h with no observable effect on any of the Gram negative bacteria. However, after 12 h, zones of inhibition were only observed for Ps. aeruginosa. In contrast, using the suspension assay, addition of Cu (II) salts to PRE solutions extended the activities resulting in no detectable growth being observed for the PRE/Cu (II) combination against E. coli, Ps. aeruginosa and P. mirabilis. Minimal antimicrobial activity was observed following incubation with Fe (II), Mn (II) or Zn (II) salts alone or in combination with PRE against any of the organisms in the test panel. The addition of vitamin C markedly enhanced the activities of both PRE/Fe (II) and PRE/Cu (II) combinations against S. aureus. CONCLUSION: This is the first report demonstrating the enhanced efficacy of PRE/metal salt combinations in the presence of the stabilising agent vitamin C, to which all isolates were sensitive with the exception of B. subtilis. This study has validated the exploration of PRE along with additives such as metal salts and vitamin C as novel antimicrobial combinations