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## Mapping of molecular gas inflow towards the Seyfert nucleus of NGC 4051 using Gemini NIFS

Riffel, Rogemar André; Storchi-Bergmann, Thaisa; Winge, Claudia; McGregor, Peter J.; Beck, Tracy; Schmitt, Henrique Roberto
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
25.8%
We present 2D stellar and gaseous kinematics of the inner ~ 130×180 pc² of the Narrow-Line Seyfert 1 galaxy NGC4051 at a sampling of 4.5 pc, from near-infrared K-band spectroscopic observations obtained with the Gemini’s Near-infrared Integral Field Spectrograph (NIFS) operating with the ALTAIR adaptive optics module. We have used the CO absorption band heads around 2.3 μm to obtain the stellar kinematics which show the turnover of the rotation curve at only ≈ 55 pc from the nucleus, revealing a highly concentrated gravitational potential. The stellar velocity dispersion of the bulge is ≈ 60 km s-ˡ – implying on a nuclear black hole mass of ≈ 10 6 Mʘ – within which patches of lower velocity dispersion suggest the presence of regions of more recent star formation. From measurements of the emission-line profiles we have constructed 2D maps for the flux distributions, line ratios, radial velocities and gas velocity dispersions for the H2, HII and [Ca VIII] emitting gas. Each emission-line samples a distinct kinematics. The Brγ emission-line shows no rotation as well as no blueshifts or redshifts in excess of 30 km s-ˡ, and is thus not restricted to the galaxy plane. The [Ca VIII] coronal region is compact but resolved...

## Quality control on radiant heaters manufacture

González Fernández, Daniel Aquilino; Madruga Saavedra, Francisco Javier; Ibarra Castanedo, Clemente; Conde Portilla, Olga María; López Higuera, José Miguel
Fonte: SPIE Society of Photo-Optical Instrumentation Engineers Publicador: SPIE Society of Photo-Optical Instrumentation Engineers
Tipo: info:eu-repo/semantics/conferenceObject; publishedVersion
ENG
Relevância na Pesquisa
45.87%
An inspection process of radiant heaters is presented in this paper. The proposed non destructive testing and evaluation (NDT and E) technique for defect assessment of radiant heaters is based on infrared thermography images properly acquired and processed. The technique can be used in on-line fabrication quality control radiant heaters manufacturing processes. By exciting the heater with a very short electrical pulse, a sequence of thermographic images is captured by an infrared camera and then analyzed. Regardless of the electrical excitation applied to the heating element of the heater, the electrical power supplied will dissipate at the resistor. Provided enough spatial resolution, the heaters could be tested with an infrared camera capturing the radiated heat. The analysis of the heating wire during the heating flank shows differences among pixels corresponding to defective points and pixels belonging to non-defective areas of the wire. The automation is provided by the development of an algorithm that looks for the slope of the heating evolution of each pixel. A Radon Transform based algorithm is here proposed to reduce human intervention providing just one image where an operator could quickly locate possible defects.

## Rational production of veneer by IR-heating of green wood during peeling: Modeling experiments

DUPLEIX, Anna; OULD AHMEDOU, Sid' Ahmed; BLÉRON, Laurent; ROSSI, Fréderic; HUGHES, Mark
Fonte: De Gruyter Publicador: De Gruyter
EN
Relevância na Pesquisa
45.86%
Heating green wood logs by infrared (IR) radiation during peeling for veneer production has been numerically simulated, focusing on the heating kinetics of a green wood cylinder rotating with a decreasing radius. The results confi rm those of previous experiments, that this kind of heating is a promising alternative to soaking wood prior to peeling. The model integrates the green wood parameters such as moisture content, density, distribution and ratios of earlywood and latewood, on the one hand, and the peeling conditions of veneer thickness and peeling speed, on the other. The following heat transfer processes were considered: conduction within the bolt, external heating by the IR source, and convection between the bolt surface and the external environment. The outputs were the temperatures of the bolt surface and of layers several millimeters deep. For maximal heat penetration, the bolt should turn in front of the IR source before cutting starts and the IR source should be positioned at the greatest angular distance ahead of the knife. Several heating scenarios could be simulated by the model, thus it is a useful decision-making tool for the design of an in-line IR heating system installed on the peeling lathe.; Institut Carnot ARTS...

## Experimental validation of green wood peeling assisted by IR heating – some analytical system design considerations

DUPLEIX, anna; BATSALE, Jean-Christophe; KUSIAK, Andrzej; HUGHES, Mark; DENAUD, Louis
Fonte: de gruyter Publicador: de gruyter
EN
Relevância na Pesquisa
65.76%
Experimental results have been used to validate a 2D simulation model in order to check its reliability in predicting the heating of a green log rotating under an IR heating source. For the purpose of validation, it was assumed that this experimental situation could be described by simplified analytical solutions. This assumption has been confirmed. Knowing the thermal and physical characteristics of green wood, two methods are now available to calculate rapidly the temperature within the wood and the maximum surface temperature reached by a green log rotating under an IR heating source: (1) by numerical simulation and (2) by analytical equations which dispense with the computationally intensive finite element method. Experimental results, validated by both methods, show that an IR heating system embedded on an industrial peeling machine would not warm-up green wood to the required peeling temperature at current peeling speeds.; The research was carried out with the use of equipment funded by the French National Agency for Research under the program "Investments for the Future" (ANR-10-EQPX-16

## On-line monitoring of methane in sewer air

Liu, Yiwen; Sharma, Keshab R.; Murthy, Sudhir; Johnson, Ian; Evans, Ted; Yuan, Zhiguo
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.67%
Methane is a highly potent greenhouse gas and contributes significantly to climate change. Recent studies have shown significant methane production in sewers. The studies conducted so far have relied on manual sampling followed by off-line laboratory-based chromatography analysis. These methods are labor-intensive when measuring methane emissions from a large number of sewers, and do not capture the dynamic variations in methane production. In this study, we investigated the suitability of infrared spectroscopy-based on-line methane sensors for measuring methane in humid and condensing sewer air. Two such sensors were comprehensively tested in the laboratory. Both sensors displayed high linearity (R2 > 0.999), with a detection limit of 0.023% and 0.110% by volume, respectively. Both sensors were robust against ambient temperature variations in the range of 5 to 35°C. While one sensor was robust against humidity variations, the other was found to be significantly affected by humidity. However, the problem was solved by equipping the sensor with a heating unit to increase the sensor surface temperature to 35°C. Field studies at three sites confirmed the performance and accuracy of the sensors when applied to actual sewer conditions...

## ISO measurements of [CII] line variations in galaxies

Malhotra, S.; Helou, G.; Stacey, G.; Hollenbach, D.; Lord, S.; Beichman, C. A.; Dinerstein, H.; Hunter, D. A.; Lo, K. Y.; Lu, N. Y.; Rubin, R. H.; Silbermann, N.; Thronson Jr., H. A.; Werner, M. W.
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
35.89%

## Resolving the Far-IR Line Deficit: Photoelectric Heating and Far-IR Line Cooling in NGC 1097 and NGC 4559

Croxall, Kevin V.; Armus, L.; Beirão, P.; Helou, G.; Appleton, P. N.
Fonte: American Astronomical Society Publicador: American Astronomical Society
Tipo: Article; PeerReviewed Formato: application/pdf
Relevância na Pesquisa
25.92%
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 [C II] 158 μm, [O I] 63 μm, and [N II] 122 μm 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, ([C II] + [O I])/TIR, decreases as the far-infrared (far-IR) color, ν_f ν(70 μm) νf_ν(100 μm), increases. In contrast, the ratio of far-IR cooling to total PAH emission, ([C II] + [O I])/PAH, is a near constant ~6% over a wide range of far-IR color, 0.5 < νf_ν(70 μm) νf_ν(100 μm) ≾ 0.95. In the warmest regions, where νf_ν(70 μm) νf_ν(100 μm) ≳ 0.95, the ratio ([C II] + [OI])/PAH drops rapidly to 4%. We derived representative values of the local ultraviolet radiation density, G_0, and the gas density, n_H, by comparing our observations to models of photodissociation regions. The ratio G_0/n_H...

## Detection of H_2 Pure Rotational Line Emission from the GG Tauri Binary System

Thi, Wing-Fai; van Dishoeck, Ewine F.; Blake, Geoffrey A.; van Zadelhoff, Gerd-Jan; Hogerheijde, Michiel R.
Fonte: American Astronomical Society Publicador: American Astronomical Society
Tipo: Article; PeerReviewed Formato: application/pdf
Relevância na Pesquisa
35.66%
We present the first detection of the low-lying pure rotational emission lines of H_2 from circumstellar disks around T Tauri stars, using the Short Wavelength Spectrometer on the Infrared Space Observatory. These lines provide a direct measure of the total amount of warm molecular gas in disks. The J = 2 → 0 S(0) line at 28.218 μm and the J = 3 → 1 S(1) line at 17.035 μm have been observed toward the double binary system GG Tau. Together with limits on the J = 5 → 3 S(3) and J = 7 → 5 S(5) lines, the data suggest the presence of gas at T_(kin) ≈ 110 ± 10 K with a mass of (3.6 ± 2.0) × 10^(-3) M_☉ (±3 σ). This amounts to ~3% of the total gas + dust mass of the circumbinary disk as imaged by millimeter interferometry, but it is larger than the estimated mass of the circumstellar disk(s). Possible origins for the warm gas seen in H_2 are discussed in terms of photon and wind-shock heating mechanisms of the circumbinary material, and comparisons with model calculations are made.

## Searching for gas emission lines in Spitzer Infrared Spectrograph (IRS) spectra of young stars in Taurus

Baldovin-Saavedra, C.; Audard, M.; Güedel, M.; Rebull, L. M.; Padgett, D. L.; Skinner, S. L.; Carmona, A.; Glauser, A. M.; Fajardo-Acosta, S. B.
Fonte: EDP Sciences Publicador: EDP Sciences
Tipo: Article; PeerReviewed Formato: application/pdf
Relevância na Pesquisa
25.83%
Context. Our knowledge of circumstellar disks has traditionally been based on studies of dust. However, gas dominates the disk mass and its study is key to our understanding of accretion, outflows, and ultimately planet formation. The Spitzer Space Telescope provides access to gas emission lines in the mid-infrared, providing crucial new diagnostics of the physical conditions in accretion disks and outflows. Aims. We seek to identify gas emission lines in mid-infrared spectra of 64 pre-main-sequence stars in Taurus. Using line luminosities and other known star-disk-outflow parameters, we aim to identify correlations that will help to constrain gas heating, excitation mechanisms, and the line formation. Methods. We have based our study on Spitzer observations using the Infrared Spectrograph (IRS), mainly with the high-resolution modules. Line luminosities (or 3σ upper limits) have been obtained by fitting Gaussian profiles to the lines. We have further searched for correlations between the line luminosities and different parameters related to the star-disk system. Results. We have detected H_2 (17.03, 28.22 μm) emission in 6 objects, [Ne II] (12.81 μm) emission in 18 objects, and [Fe II] (17.93, 25.99 μm) emission in 7 objects. [Ne II] detections are found primarily in Class II objects. The luminosity of the [Ne II] line (L_(NeII)) is in general higher for objects known to drive jets than for those without known jets...

## Cool dust heating and temperature mixing in nearby star-forming galaxies

Hunt, L. K.; Draine, B. T.; Bianchi, S.; Gordon, K. D.; Aniano, G.; Calzetti, D.; Dale, D. A.; Helou, G.; Hinz, J. L.; Kennicutt, R. C.; Roussel, H.; Wilson, C. D.; Bolatto, A.; Boquien, M.; Croxall, K. V.; Galametz, M.; Gil de Paz, A.; Koda, J.; Muñoz-M
Fonte: EDP Sciences Publicador: EDP Sciences
Tipo: Article; PeerReviewed Formato: application/pdf; application/pdf
Relevância na Pesquisa
25.83%
Physical conditions of the interstellar medium in galaxies are closely linked to the ambient radiation field and the heating of dust grains. In order to characterize dust properties in galaxies over a wide range of physical conditions, we present here the radial surface brightness profiles of the entire sample of 61 galaxies from Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH). The main goal of our work is the characterization of the grain emissivities, dust temperatures, and interstellar radiation fields (ISRFs) responsible for heating the dust. We first fit the radial profiles with exponential functions in order to compare stellar and cool-dust disk scalelengths, as measured by 3.6 μm and 250 μm surface brightnesses. Our results show that the stellar and dust scalelengths are comparable, with a mean ratio of 1.04, although several galaxies show dust-to-stellar scalelength ratios of 1.5 or more. We then fit the far-infrared spectral energy distribution (SED) in each annular region with single-temperature modified blackbodies using both variable (MBBV) and fixed (MBBF) emissivity indices β, as well as with physically motivated dust models. The KINGFISH profiles are well suited to examining trends of dust temperature T_(dust) and β because they span a factor of ~200 in the ISRF intensity heating the bulk of the dust mass...

## CO J = 2-1 Line Emission in Cluster Galaxies at z ~ 1: Fueling Star Formation in Dense Environments

Wagg, Jeff; Pope, Alexandra; Alberts, Stacey; Armus, Lee; Brodwin, Mark; Bussmann, Robert S.; Desai, Vandana; Dey, Arjun; Jannuzi, Buell T.; Le Floc'h, Emeric; Melbourne, Jason; Stern, Daniel
Fonte: American Astronomical Society Publicador: American Astronomical Society
Tipo: Article; PeerReviewed Formato: application/pdf