The impact of Lyα emission line heating and cooling on the cosmic dawn 21-cm signal

ABSTRACT Allowing for enhanced Lyα photon line emission from Population III dominated stellar systems in the first forming galaxies, we show the 21-cm cosmic dawn signal at 10 < $z$ < 30 may substantially differ from standard scenarios. Energy transfer by Lyα photons emerging from galaxies may heat intergalactic gas if H ii regions within galaxies are recombination bound, or cool the gas faster than by adiabatic expansion if reddened by winds internal to the haloes. In some extreme cases, differential 21-cm antenna temperatures near −500 mK may be achieved at 15 < $z$ < 25, similar to the signature detected by the EDGES 21-cm cosmic dawn experiment.

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Properties of LBGs with [OIII] detection at z ∼ 3.5

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935975 ◽

2019 ◽

Vol 631 ◽

pp. A123 ◽

Cited By ~ 1

Author(s):

Fang-Ting Yuan ◽

Denis Burgarella ◽

David Corre ◽

Veronique Buat ◽

Médéric Boquien ◽

...

Keyword(s):

Physical Properties ◽

Emission Line ◽

Near Infrared ◽

Spectral Energy Distribution ◽

Formation Rate ◽

Line Emission ◽

Stellar Mass ◽

Spectral Energy ◽

Emission Data ◽

The Impact

Context. Nebular emission lines are critical to measure physical properties in the ionized gas (e.g., metallicity, the star formation rate, or dust attenuation). They also account for a significant fraction of broadband fluxes, in particular at the highest redshifts, and therefore can strongly affect the determination of other physical properties, such as the stellar mass, which are crucial in shaping our understanding of galaxy formation and evolution. Aims. We investigate a sample of 51 Lyman break galaxies at 3.0 < zspec < 3.8 with detected [OIII] line emissions and estimated the physical properties of these galaxies to examine the impact of including nebular emission data in the Spectral energy distribution (SED) fitting. Methods. We used the Code Investigating GALaxy Emission (CIGALE) to fit the rest-frame ultraviolet-to-near-infrared SEDs of these galaxies and their emission line data simultaneously. We ran CIGALE with and without the nebular model or the emission line data, and compare the results to show the importance of including the nebular emission line data in the SED fitting. Results. We find that without the nebular model, the SED fitting overestimates the stellar mass due to the strong [OIII] lines that are redshifted to the Ks-band, which is consistent with previous results. The emission line data are necessary to constrain the nebular model in the SED fitting. We examine the Ks-band excess, which is mostly used to estimate the emissions of the [OIII]+Hβ lines when there is no spectral data, and we find that the estimation and observation are statistically consistent. However, the difference can reach up to more than 1 dex in some catastrophic cases, which shows the importance of obtaining spectroscopic measurements for these lines. We also estimate the equivalent width of the Hβ absorption and find it negligible compared to the Hβ emission. Conclusions. Line emission is important to constrain the nebular models and to obtain reliable estimates of the physical properties of galaxies. These data should be taken into account in the SED fitting.

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J-PLUS: Synthetic galaxy catalogues with emission lines for photometric surveys

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936232 ◽

2019 ◽

Vol 631 ◽

pp. A82 ◽

Cited By ~ 3

Author(s):

David Izquierdo-Villalba ◽

Raul E. Angulo ◽

Alvaro Orsi ◽

Guillaume Hurier ◽

Gonzalo Vilella-Rojo ◽

...

Keyword(s):

Emission Line ◽

Narrow Band ◽

Spectral Energy Distribution ◽

Broad Band ◽

Line Emission ◽

Spectral Energy ◽

Filter Method ◽

Medium Band ◽

Emission Line Galaxies ◽

The Impact

We present a synthetic galaxy lightcone specially designed for narrow-band optical photometric surveys. To reduce time-discreteness effects, unlike previous works, we directly include the lightcone construction in the L-Galaxies semi-analytic model applied to the subhalo merger trees of the Millennium simulation. Additionally, we add a model for the nebular emission in star-forming regions, which is crucial for correctly predicting the narrow- and medium-band photometry of galaxies. Specifically, we consider, individually for each galaxy, the contribution of 9 different lines: Lyα (1216 Å), Hβ (4861 Å), Hα (6563 Å), [O II] (3727 Å, 3729 Å), [O III] (4959 Å, 5007 Å), [Ne III] (3870 Å), [O I] (6300 Å), [N II] (6548 Å, 6583 Å), and [S II] (6717 Å, 6731 Å). We validate our lightcone by comparing galaxy number counts, angular clustering, and Hα, Hβ, [O II], and [O III]5007 luminosity functions to a compilation of observations. As an application of our mock lightcones, we generated catalogues tailored for J-PLUS, a large optical galaxy survey featuring five broad-band and seven medium-band filters. We study the ability of the survey to correctly identify, with a simple three-filter method, a population of emission-line galaxies at various redshifts. We show that the 4000 Å break in the spectral energy distribution of galaxies can be misidentified as line emission. However, all significant excess (> 0.4 mag) can be correctly and unambiguously attributed to emission-line galaxies. Our catalogues are publicly released to facilitate their use in interpreting narrow-band surveys and in quantifying the impact of line emission in broad-band photometry.

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FeXIV Line Emission Polarization of the July 11, 1991 Solar Corona

International Astronomical Union Colloquium ◽

10.1017/s0252921100026002 ◽

1994 ◽

Vol 144 ◽

pp. 541-547

Author(s):

J. Sýkora ◽

J. Rybák ◽

P. Ambrož

Keyword(s):

High Resolution ◽

Solar Corona ◽

Emission Line ◽

Solar Eclipse ◽

White Light ◽

Preliminary Analysis ◽

Line Emission ◽

Total Solar Eclipse ◽

Degree Of Polarization ◽

High Resolution Images

AbstractHigh resolution images, obtained during July 11, 1991 total solar eclipse, allowed us to estimate the degree of solar corona polarization in the light of FeXIV 530.3 nm emission line and in the white light, as well. Very preliminary analysis reveals remarkable differences in the degree of polarization for both sets of data, particularly as for level of polarization and its distribution around the Sun’s limb.

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Monitoring the Structural Dynamics of U2 snRNA Via Single-Molecule Förster Resonance Energy Transfer

10.31237/osf.io/9j8gq ◽

2018 ◽

Author(s):

Alexander Carl DeHaven

Keyword(s):

Energy Transfer ◽

Structural Dynamics ◽

Single Molecule ◽

Conformational Dynamics ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Förster Resonance Energy Transfer ◽

U2 Snrna ◽

Folding Dynamics ◽

The Impact

This thesis contains four topic areas: a review of single-molecule microscropy methods and splicing, conformational dynamics of stem II of the U2 snRNA, the impact of post-transcriptional modifications on U2 snRNA folding dynamics, and preliminary findings on Mango aptamer folding dynamics.

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Damage Evolution of Granodiorite after Heating and Cooling Treatments

Minerals ◽

10.3390/min11070779 ◽

2021 ◽

Vol 11 (7) ◽

pp. 779

Author(s):

Mohamed Gomah ◽

Guichen Li ◽

Salah Bader ◽

Mohamed Elkarmoty ◽

Mohamed Ismael

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Failure Mode ◽

Physical And Mechanical Properties ◽

P Wave ◽

Physical Parameters ◽

Slow Cooling ◽

Heating And Cooling ◽

Natural Rock ◽

The Impact

The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian granodiorite as a degrading factor. The samples were heated to various temperatures (200, 400, 600, and 800 °C) and then cooled at different rates, either slowly cooled in the oven and air or quickly cooled in water. The porosity, water absorption, P-wave velocity, tensile strength, failure mode, and associated microstructural alterations due to thermal effect have been studied. The study revealed that the granodiorite has a slight drop in tensile strength, up to 400 °C, for slow cooling routes and that most of the physical attributes are comparable to natural rock. Despite this, granodiorite thermal deterioration is substantially higher for quick cooling than for slow cooling. Between 400:600 °C is ‘the transitional stage’, where the physical and mechanical characteristics degraded exponentially for all cooling pathways. Independent of the cooling method, the granodiorite showed a ductile failure mode associated with reduced peak tensile strengths. Additionally, the microstructure altered from predominantly intergranular cracking to more trans-granular cracking at 600 °C. The integrity of the granodiorite structure was compromised at 800 °C, the physical parameters deteriorated, and the rock tensile strength was negligible. In this research, the temperatures of 400, 600, and 800 °C were remarked to be typical of three divergent phases of granodiorite mechanical and physical properties evolution. Furthermore, 400 °C could be considered as the threshold limit for Egyptian granodiorite physical and mechanical properties for typical thermal underground applications.

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Dynamic Repair and Robust Optimization of Complex Networks

Mathematical Problems in Engineering ◽

10.1155/2020/4131502 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Pengtao Zhang ◽

Peng Bai ◽

Chaoqi Fu ◽

Shanshan Li

Keyword(s):

Energy Transfer ◽

Repair Process ◽

Recovery Efficiency ◽

Repair Strategy ◽

Coupling Structure ◽

Secondary Failure ◽

Fundamental Reason ◽

Network Functions ◽

The Impact ◽

Failure Node

Network repair is indispensable for maintaining network security. Conventional static repair is relatively inefficient. In this study, by considering the energy transfer between nodes, a dynamic repair model was established. The fundamental reason for the secondary failure of repaired nodes during the dynamic repair process is the coupling structure of failure networks. A dynamic repair strategy was proposed that can effectively prevent the secondary failure of repair nodes influenced by energy during repair and can cause the redundant capacity of repair nodes to be used reasonably. By turning off the energy transfer function of the link to control the excessive flow of energy into the repair node to avoid the occurrence of secondary failure; on the other hand, by sharing part of the load of the failure node, realize the rational use of the redundant capacity of the repair node to reduce the impact of the failure node on the overall function of the network. The proposed strategy mitigated the effect of failure nodes on network functions and substantially improved the recovery efficiency of network functions. Furthermore, redundant edges, behaving as energy redundant links in a network structure, can considerably improve the robustness of the network by optimizing the removal of redundant edges. Dynamic repair is not only an efficient repair method but also a highly flexible choice for network repair.

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Lyα Emitting Galaxies as a Probe of Reionisation

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2014.33 ◽

2014 ◽

Vol 31 ◽

Cited By ~ 133

Author(s):

Mark Dijkstra

Keyword(s):

Rapid Evolution ◽

Line Emission ◽

Coherent Scattering ◽

Neutral Fraction ◽

Collisional Excitation ◽

Intergalactic Gas ◽

Star Forming ◽

Bolometric Luminosity ◽

Radiative Processes ◽

Sudden Reduction

AbstractThe Epoch of Reionization (EoR) represents a milestone in the evolution of our Universe. Star-forming galaxies that existed during the EoR likely emitted a significant fraction ( ~ 5 − 40%) of their bolometric luminosity as Lyα line emission. However, neutral intergalactic gas that existed during the EoR was opaque to Lyα emission that escaped from galaxies during this epoch, which makes it difficult to observe. The neutral intergalactic medium (IGM) may thus reveal itself by suppressing the Lyα flux from background galaxies. Interestingly, a ‘sudden’ reduction in the observed Lyα flux has now been observed in galaxies at z > 6. This review contains a detailed summary of Lyα radiative processes: I describe (i) the main Lyα emission processes, including collisional-excitation & recombination (and derive the origin of the famous factor ‘0.68’), and (ii) basic radiative transfer concepts, including e.g. partially coherent scattering, frequency diffusion, resonant versus wing scattering, optically thick versus ‘extremely’ optically thick (static/outflowing/collapsing) media, and multiphase media. Following this review, I derive expressions for the Gunn-Peterson optical depth of the IGM during (inhomogeneous) reionisation and post-reionisation. I then describe why current observations appear to require a very rapid evolution of volume-averaged neutral fraction of hydrogen in the context of realistic inhomogeneous reionisation models, and discuss uncertainties in this interpretation. Finally, I describe how existing & futures surveys and instruments can help reduce these uncertainties, and allow us to fully exploit Lyα emitting galaxies as a probe of the EoR.

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The impact of technology on architecture in Iran with focus on saving in energy consumption

Environment Conservation Journal ◽

10.36953/ecj.2015.se1610 ◽

2015 ◽

Vol 16 (SE) ◽

pp. 97-103

Author(s):

Allah Bakhsh Kavoosi ◽

Shahin Heidari ◽

Hamed Mazaherian

Keyword(s):

Energy Consumption ◽

Energy Demand ◽

Industrial Revolution ◽

Demand Prediction ◽

Interior Spaces ◽

Heating And Cooling ◽

Impact Of Technology ◽

Contemporary Architecture ◽

The Impact ◽

The Given

Growth and development of technology caused enormous transformation and change in the world after Industrial Revolution. The contemporary human has prepared the platform for their realization in many activities that the humans were unable to do it in the past time and struck the dream of their realization in their mind so that today doing many of those activities have been apparently practical by human. This accelerating growth accompanied with consuming a lot of energy where with respect to restriction of the given existing resources, it created energy crises. On the other hand, along with growth in industry and requirement for manpower and immigration from village to city and basic architectural changes in houses, which have emerged due to change in social structure it has led to change in lifestyle and type and quantity of consuming energy in contemporary architecture. Inter alia, with increase in human’s capability, cooling and heating and acoustic and lighting technologies were also changed in architecture and using mechanical system was replaced by traditional systems. Application of modern systems, which resulted from growth of industry and development of technology and it unfortunately, caused further manipulation in nature and destruction of it by human in addition to improving capability and potential of human’s creativity. With respect to growth of population and further need for housing and tendency to the dependent heating and cooling systems to them in this article we may notice that the housing is assumed as the greatest consumer of energy to create balance among the exterior and interior spaces in line with creating welfare conditions for heating and cooling and lighting. The tables of energy demand prediction in Iran show that these costs and energy consumption will be dubbed with energy control smart management in architecture.

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Challenges and Techniques for Simulating Line Emission

Galaxies ◽

10.3390/galaxies6040100 ◽

2018 ◽

Vol 6 (4) ◽

pp. 100 ◽

Cited By ~ 8

Author(s):

Karen Olsen ◽

Andrea Pallottini ◽

Aida Wofford ◽

Marios Chatzikos ◽

Mitchell Revalski ◽

...

Keyword(s):

Interstellar Medium ◽

Emission Line ◽

Line Emission ◽

Emission Lines ◽

Synthetic Spectra ◽

Recent Advances ◽

The Future ◽

Important Quality ◽

Circumgalactic Medium

Modeling emission lines from the millimeter to the UV and producing synthetic spectra is crucial for a good understanding of observations, yet it is an art filled with hazards. This is the proceedings of “Walking the Line”, a 3-day conference held in 2018 that brought together scientists working on different aspects of emission line simulations, in order to share knowledge and discuss the methodology. Emission lines across the spectrum from the millimeter to the UV were discussed, with most of the focus on the interstellar medium, but also some topics on the circumgalactic medium. The most important quality of a useful model is a good synergy with observations and experiments. Challenges in simulating line emission are identified, some of which are already being worked upon, and others that must be addressed in the future for models to agree with observations. Recent advances in several areas aiming at achieving that synergy are summarized here, from micro-physical to galactic and circum-galactic scale.

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