We present a novel method for estimating galaxy physical properties from spectral energy distributions (SEDs) as an alternative to template fitting techniques and based on self-organizing maps (SOMs) ...to learn the high-dimensional manifold of a photometric galaxy catalog. The method has previously been tested with hydrodynamical simulations in Davidzon et al. (2019, MNRAS, 489, 4817), however, here it is applied to real data for the first time. It is crucial for its implementation to build the SOM with a high-quality panchromatic data set, thus we selected “COSMOS2020” galaxy catalog for this purpose. After the training and calibration steps with COSMOS2020, other galaxies can be processed through SOMs to obtain an estimate of their stellar mass and star formation rate (SFR). Both quantities resulted in a good agreement with independent measurements derived from more extended photometric baseline and, in addition, their combination (i.e., the SFR vs. stellar mass diagram) shows a main sequence of star-forming galaxies that is consistent with the findings of previous studies. We discuss the advantages of this method compared to traditional SED fitting, highlighting the impact of replacing the usual synthetic templates with a collection of empirical SEDs built by the SOM in a “data-driven” way. Such an approach also allows, even for extremely large data sets, for an efficient visual inspection to identify photometric errors or peculiar galaxy types. While also considering the computational speed of this new estimator, we argue that it will play a valuable role in the analysis of oncoming large-area surveys such as
Euclid
of the Legacy Survey of Space and Time at the
Vera C. Rubin
Telescope.
We use data taken as part of Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) observations of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) to identify massive ...and evolved galaxies at 3 < z < 4.5. This is performed using the strength of the Balmer break feature at rest-frame 3648 A, which is a diagnostic of the age of the stellar population in galaxies. Using the WFC3 H-band-selected catalog for the CANDELS GOODS-S field and deep multi-waveband photometry from optical (HST) to mid-infrared (Spitzer) wavelengths, we identify a population of old and evolved post-starburst galaxies based on the strength of their Balmer breaks (Balmer break galaxies, BBGs). The galaxies are also selected to be bright in rest-frame near-IR wavelengths and hence massive. We identify a total of 16 BBGs. Fitting the spectral energy distribution of the BBGs shows that the candidate galaxies have average estimated ages of ~800 Myr and average stellar masses of ~5 x 10 super(10) M sub(middot in circle), consistent with being old and massive systems. Two of our BBG candidates are also identified by the criteria that are sensitive to star-forming galaxies (Lyman break galaxy selection). We find a number density of ~3.2 x 10 super(-5) Mpc super(-3) for the BBGs, corresponding to a mass density of ~2.0 x 10 super(6) M sub(middot in circle) Mpc super(-3) in the redshift range covering the survey. Given the old age and the passive evolution, it is argued that some of these objects formed the bulk of their mass only a few hundred million years after the big bang.
A new method for flux weakening of either surface permanent magnet or buried permanent magnet machines is proposed in this article. This method, termed the double-bridge winding switching technique, ...can reliably double the field-weakening speed range of permanent magnet motors. This feature is significant since extending the constant power speed ratio of surface permanent magnet machines is a particularly challenging task due to the presence of low-permeability surface magnets and the resulting low machine inductance. In this method of field weakening, the usual three-phase motor windings are separated into two portions, and each portion is connected to an inverter. The article discusses the stator winding arrangement, which allows the normal and high-speed operation of the machine along with the constant output power and reports simulation results taken from finite-element analysis.
Stress grading (SG) layer in cable terminations limits the critical electric field and properties of SG materials are important issues which have to be considered during manufacturing and selecting ...procedure. In this paper, two different types of (SG) materials are analyzed by both theory and test. According to the applied theory, important parameters as: electrical resistivity, breakdown voltage and thermal conductivity are determined by experiments. Experimental steps are defined in the paper with which theory and experiments are matched together to complete the investigation. The paper discusses electro-thermal breakdown theory and quality of two different SG layers based on the test results. The theory and experimental procedure can be used for prediction of breakdown voltage in cable terminations. The employed method is useful for qualifying the cable terminations by users who want to buy and install heat shrink cable terminations.
► Proposing a structure for MTO firms to select an appropriate combination of orders. ► Prioritizing the orders and so, evaluating the orders regarding their priority. ► Calculating rough-cut ...capacity for each order depends on priority level. ► Improving the Kingsman backward method in computing the ERD and OCD. ► Making final decisions on orders based on their due dates, MAD, ERD and OCD.
In order to improve the quality of decision about orders incoming to make to order (MTO) company, an effective evaluation approach is essential. So, in this paper a comprehensive decision making structure is presented for acceptance or rejection of incoming orders. The aim of the proposed structure is to manage the arriving orders so that the MTO system just proceeds to produce those arriving orders which are feasible and profitable for the system. The proposed structure composed of three phases. At the first phase, arriving orders are prioritized into high and low priority orders, considering characteristics of order and customer and utilizing technique for order performance by similarity to ideal solution (TOPSIS). At the second phase, rough-cut capacity was calculated for each order regarding priority level and so, acceptance or rejection decision is taken based on it. Finally, at the third phase, the previous phase accepted orders are evaluated based on their due dates and material arrival times and final decisions for orders are made. At the end, the effectiveness of the proposed structure is demonstrated through a case study.
We investigate the properties of ~7000 narrow-band selected galaxies with strong H beta +OIII and OII nebular emission lines from the High-z Emission-Line Survey between z ~ 0.8 and 5.0. Our sample ...covers a wide range in stellar mass (...), rest-frame equivalent widths (...), and line luminosities (...). We measure the H beta +OIII-selected stellar mass functions out to z ~ 3.5 and find that both ... and ... increases with cosmic time. The OII-selected stellar mass functions show a constant ... and a strong, increasing evolution with cosmic time in ... in line with H alpha studies. We also investigate the evolution of the EW sub( rest) as a function of redshift with a fixed mass range (...) and find an increasing trend best represented by ... and ... up to z ~ 2 and ~3 for H beta +OIII and OII emitters, respectively. This is the first time that the EW sub( rest) evolution has been directly measured for H beta +OIII and OII emitters up to these redshifts. There is evidence for a slower evolution for z > 2 in the H beta +OIII EW sub( rest) and a decreasing trend for z > 3 in the OII EW sub( rest) evolution, which would imply low OII EW at the highest redshifts and higher OIII/OII line ratios. This suggests that the ionization parameter at higher redshift may be significantly higher than the local Universe. Our results set the stage for future near-IR space-based spectroscopic surveys to test our extrapolated predictions and also produce z > 5 measurements to constrain the high-z end of the EW sub( rest) and OIII/OII evolution. (ProQuest: ... denotes formulae/symbols omitted.)
The ALPINE-ALMA [CII] survey O. Le Fèvre; Béthermin, M; Faisst, A ...
Astronomy and astrophysics (Berlin),
11/2020, Letnik:
643
Journal Article
Recenzirano
Odprti dostop
The ALMA-ALPINE CII survey is aimed at characterizing the properties of a sample of normal star-forming galaxies (SFGs). The ALMA Large Program to INvestigate (ALPINE) features 118 galaxies observed ...in the CII-158 μm line and far infrared (FIR) continuum emission during the period of rapid mass assembly, right after the end of the HI reionization, at redshifts of 4 < z < 6. We present the survey science goals, the observational strategy, and the sample selection of the 118 galaxies observed with ALMA, with an average beam minor axis of about 0.85″, or ∼5 kpc at the median redshift of the survey. The properties of the sample are described, including spectroscopic redshifts derived from the UV-rest frame, stellar masses, and star-formation rates obtained from a spectral energy distribution (SED) fitting. The observed properties derived from the ALMA data are presented and discussed in terms of the overall detection rate in CII and FIR continuum, with the observed signal-to-noise distribution. The sample is representative of the SFG population in the main sequence at these redshifts. The overall detection rate in CII is 64% for a signal-to-noise ratio (S/N) threshold larger than 3.5 corresponding to a 95% purity (40% detection rate for S/N > 5). Based on a visual inspection of the CII data cubes together with the large wealth of ancillary data, we find a surprisingly wide range of galaxy types, including 40% that are mergers, 20% extended and dispersion-dominated, 13% compact, and 11% rotating discs, with the remaining 16% too faint to be classified. This diversity indicates that a wide array of physical processes must be at work at this epoch, first and foremost, those of galaxy mergers. This paper sets a reference sample for the gas distribution in normal SFGs at 4 < z < 6, a key epoch in galaxy assembly, which is ideally suited for studies with future facilities, such as the James Webb Space Telescope (JWST) and the Extremely Large Telescopes (ELTs).
Connected and automated vehicles present significant opportunities for energy saving and efficiency, especially for hybrid electric vehicles. Information such as estimated trip duration, path, time, ...and ambient conditions can be utilized to predict the future thermal and traction loads for a connected vehicle. One of the most energy-intensive sub-systems of a hybrid electric or fully electric vehicle is cabin heating in cold climates. In this work, an innovative co-optimization platform is developed to optimize: (i) cabin heating using combined electrical resistance heating and engine heat assist, (ii) multi-mode powertrain operation during charge depletion, and (iii) exhaust aftertreatment system thermal management to minimize catalyst light-off fuel penalty. To this end, a model-based cabin heating and powertrain optimization platform is created and tested using extensive experimental data from a plug-in hybrid electric vehicle. Vehicle’s trip duration is estimated using vehicle connectivity data that is then used to forecast cabin heating and powertrain power demands. The results show the proposed integrated cabin and powertrain thermal management can lead to 10 % to 26% vehicle energy saving by testing for the United States Urban Dynamometer Driving Schedule and one real world drive cycle with varying elevations. In addition, the effect of variability of ambient temperature (−15 to 2 °C) on energy savings is studied using Monte Carlo simulations.
•Presents a novel co-optimization platform with increased efficiency for engine waste heat for cabin heating as well as coordinated powertrain thermal management.•Develops predictive physics-based and data-driven models to capture vehicle cabin and powertrain thermal dynamics.•Includes vehicle heating operation and powertrain testing results for winter conditions.•Shows up to 26% vehicle energy saving by co-optimization of heating operation, powertrain, and exhaust aftertreatment system.•Evaluates the designed strategies for Urban Dynamometer Driving Schedule (UDDS) drive cycle and a 45-min drive cycle with 170 m elevation variations.
In this paper a new analytical solution is applied to study heat transfer during forming of plates by flame bending process. Produced heat flux with flame, is modeled with normal Gaussian ...distribution, which moves along predefined paths on plate. Mild steel with constant thermal properties is as selected material. Results of the thermal analyses by this method show good agreement in comparison with experimental data. This method is properly applicable to estimate of flame parameters that are input parameters for thermo-mechanical simulation of the process. Reasonable accuracy of the results and diminishing of model dependency and CPU time required for thermal analyses are the advantages of this solution for the process study.
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![The nature of Hβ+[O iii] an...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0035-8711/small "The nature of Hβ+[O iii] and [O ii] emitters to z ∼ 5 with HiZELS: stellar mass functions and the evolution of EWs")
