We present spectrophotometric results of the Seyfert 2 galaxy NGC 2273. Thepresence of high-order Balmer absorption lines (H8, H9, H10) and weak equivalent widths of CaII Kλ3933, CN λ4200, G-band λ4300 and MgIb λ5...We present spectrophotometric results of the Seyfert 2 galaxy NGC 2273. Thepresence of high-order Balmer absorption lines (H8, H9, H10) and weak equivalent widths of CaII Kλ3933, CN λ4200, G-band λ4300 and MgIb λ5173 clearly indicate recent star-forming activity inthe nuclear region. Using a simple stellar population synthesis model, we find that for the bestfit, the contributions of a power-law featureless continuum, an intermediate-age (～ 10~8 yr) and anold (> 10~9 yr) stellar population to the total light at the reference normalization wavelength are10.0%, 33.4% and 56.6%, respectively. The existence of recent starburst activity is also consistentwith its high far-infrared luminosity (log L_(FIR.)/L☉ = 9.9), its infrared color indexes[α(25,60) = ― 1.81 and α(60,100) = ― 0.79, typical values for Seyfert galaxies withcircumnuclear starburst], and its q-value (2.23, ratio of infrared to radio flux, very similar tothat of normal spirals and starburst galaxies). Byrd et al. have suggested that NGC 2273 might haveinteracted with NGC 2273B in less than 10~9 yr ago, so the starburst activity in this galaxy couldhave been triggered by tidal interaction, as indicated in recent numerical simulations.展开更多
The extragalactic diffuse emission at γ-ray energies has interesting cosmological implications since these photons suffer little or no attenuation during their propagation from the site of origin. The emission could ...The extragalactic diffuse emission at γ-ray energies has interesting cosmological implications since these photons suffer little or no attenuation during their propagation from the site of origin. The emission could originate from either truly diffuse processes or from unresolved point sources such as AGNs, normal galaxies and starburst galaxies. Here, we examine the unresolved point source origin of the extragalactic γ-ray background emission from normal galaxies and starburst galaxies. γ-ray emission from normal galaxies is primarily coming from cosmic-ray interactions with interstellar matter and radiation （-90%） along with a small contribution from discrete point sources （-10%）. Starburst galaxies are expected to have enhanced supernovae activity which leads to higher cosmic-ray densities, making starburst galaxies sufficiently luminous atγ-ray energies to be detected by the current γ-ray mission （Fermi Gamma-ray Space Telescope）.展开更多
In this work,we reanalyzed 11 years of spectral data from the Fermi Large Area Telescope(Fermi-LAT)of currently observed starburst galaxies(SBGs)and star-forming galaxies(SFGs).We used a one-zone model provided by NAI...In this work,we reanalyzed 11 years of spectral data from the Fermi Large Area Telescope(Fermi-LAT)of currently observed starburst galaxies(SBGs)and star-forming galaxies(SFGs).We used a one-zone model provided by NAIMA and the hadronic origin to explain the GeV observation data of the SBGs and SFGs.We found that a protonic distribution of a power-law form with an exponential cutoff can explain the spectra of most SBGs and SFGs.However,it cannot explain the spectral hardening components of NGC 1068 and NGC 4945 in the GeV energy band.Therefore,we considered the two-zone model to well explain these phenomena.We summarized the features of two model parameters,including the spectral index,cutoff energy,and proton energy budget.Similar to the evolution of supernova remnants(SNRs)in the Milky Way,we estimated the protonic acceleration limitation inside the SBGs to be the order of 10^(2) TeV using the one-zone model;this is close to those of SNRs in the Milky Way.展开更多
A pyrazoline-containing starburst molecule, 4,4’,4"-tris[(1,3-diphenyl-4,5-dihydro-1H- pyrazol)-5-yl]-triphenylamine (Tris-5-DPP), was synthesized in a facile way, which can form amorphous thin films with glass ...A pyrazoline-containing starburst molecule, 4,4’,4"-tris[(1,3-diphenyl-4,5-dihydro-1H- pyrazol)-5-yl]-triphenylamine (Tris-5-DPP), was synthesized in a facile way, which can form amorphous thin films with glass transition temperature as high as 136 °C.展开更多
Starburst triphenylamine molecules are generally used as hole transporting materials (HTMs)for optoelectronic devices like solar cells,light emitting diode and field effect transistors .The use of starburst triphenyla...Starburst triphenylamine molecules are generally used as hole transporting materials (HTMs)for optoelectronic devices like solar cells,light emitting diode and field effect transistors .The use of starburst triphenylamine molecules like spiro-OMeTAD HTM initiated the construction of solid state perovskite solar cells (PSCs).Currently,based on triphenylamine HTMs,the highest power conversion efficiency (PCE)of PSCs is up to 22.1%.展开更多
The polymer N2200, with its π-conjugated backbone composed of alternating naphthalene diimide(NDI) and bithiophene(DT)units, has been widely used as an acceptor for all-polymer solar cells(all-PSCs) owing to its high...The polymer N2200, with its π-conjugated backbone composed of alternating naphthalene diimide(NDI) and bithiophene(DT)units, has been widely used as an acceptor for all-polymer solar cells(all-PSCs) owing to its high electron mobility and suitable ionization potential and electron affinity. Here, we developed two naphthalene diimide derivatives by modifying the molecular geometry of N2200 through the incorporation of a truxene unit as the core and NDI-DTas the branches. These starburst polymers exhibited absorption spectra and molecular orbital energy levels that were comparable to N2200. These copolymers were paired with the wide-bandgap polymer donor PTz BI-O to fabricate all-polymer solar cells(all-PSCs), which displayed impressive power conversion efficiencies up to 8.00%. The improved photovoltaic performances of all-PSCs based on these newly developed starburst acceptors can be ascribed to the combination of increased charge carrier mobilities, reduced bimolecular recombination, and formation of more favorable film morphology. These findings demonstrate that the construction of starburst polymer acceptors is a feasible strategy for the fabrication of high-performance all-PSCs.展开更多
Two novel starburst compounds (star arylamines),4,4′,4″ tris(diphenylamino) triphenylamine (TDATA) and 4,4′,4″ tris[3 methyl (phenyl) amino] triphenylamine (MTDATA),were designed and synthesized as hole transport ...Two novel starburst compounds (star arylamines),4,4′,4″ tris(diphenylamino) triphenylamine (TDATA) and 4,4′,4″ tris[3 methyl (phenyl) amino] triphenylamine (MTDATA),were designed and synthesized as hole transport materials with high glass transition temperature ( t g),good film formation and film stability,excellent hole transporting ability.展开更多
文摘We present spectrophotometric results of the Seyfert 2 galaxy NGC 2273. Thepresence of high-order Balmer absorption lines (H8, H9, H10) and weak equivalent widths of CaII Kλ3933, CN λ4200, G-band λ4300 and MgIb λ5173 clearly indicate recent star-forming activity inthe nuclear region. Using a simple stellar population synthesis model, we find that for the bestfit, the contributions of a power-law featureless continuum, an intermediate-age (～ 10~8 yr) and anold (> 10~9 yr) stellar population to the total light at the reference normalization wavelength are10.0%, 33.4% and 56.6%, respectively. The existence of recent starburst activity is also consistentwith its high far-infrared luminosity (log L_(FIR.)/L☉ = 9.9), its infrared color indexes[α(25,60) = ― 1.81 and α(60,100) = ― 0.79, typical values for Seyfert galaxies withcircumnuclear starburst], and its q-value (2.23, ratio of infrared to radio flux, very similar tothat of normal spirals and starburst galaxies). Byrd et al. have suggested that NGC 2273 might haveinteracted with NGC 2273B in less than 10~9 yr ago, so the starburst activity in this galaxy couldhave been triggered by tidal interaction, as indicated in recent numerical simulations.
基金supported by a project (Grant No.SR/S2/HEP12/2007)the Department of Space and Technology, India.
文摘The extragalactic diffuse emission at γ-ray energies has interesting cosmological implications since these photons suffer little or no attenuation during their propagation from the site of origin. The emission could originate from either truly diffuse processes or from unresolved point sources such as AGNs, normal galaxies and starburst galaxies. Here, we examine the unresolved point source origin of the extragalactic γ-ray background emission from normal galaxies and starburst galaxies. γ-ray emission from normal galaxies is primarily coming from cosmic-ray interactions with interstellar matter and radiation （-90%） along with a small contribution from discrete point sources （-10%）. Starburst galaxies are expected to have enhanced supernovae activity which leads to higher cosmic-ray densities, making starburst galaxies sufficiently luminous atγ-ray energies to be detected by the current γ-ray mission （Fermi Gamma-ray Space Telescope）.
基金support for this work from the National Key R&D Program of China(Grant No.2018YFA0404204)the National Natural Science Foundation of China(Grant Nos.U1931113,U1738211 and U193110119)+1 种基金the Foundations of Yunnan Province(2018IC059 and 2018FY001(-003))the Scientific Research Fund of Yunnan Education Department(2020Y0039)。
文摘In this work,we reanalyzed 11 years of spectral data from the Fermi Large Area Telescope(Fermi-LAT)of currently observed starburst galaxies(SBGs)and star-forming galaxies(SFGs).We used a one-zone model provided by NAIMA and the hadronic origin to explain the GeV observation data of the SBGs and SFGs.We found that a protonic distribution of a power-law form with an exponential cutoff can explain the spectra of most SBGs and SFGs.However,it cannot explain the spectral hardening components of NGC 1068 and NGC 4945 in the GeV energy band.Therefore,we considered the two-zone model to well explain these phenomena.We summarized the features of two model parameters,including the spectral index,cutoff energy,and proton energy budget.Similar to the evolution of supernova remnants(SNRs)in the Milky Way,we estimated the protonic acceleration limitation inside the SBGs to be the order of 10^(2) TeV using the one-zone model;this is close to those of SNRs in the Milky Way.
基金This work was financially supported by NNSFC and the Ministry of Science and Technology of China(Grant No.20272065 and G2000028204).
文摘A pyrazoline-containing starburst molecule, 4,4’,4"-tris[(1,3-diphenyl-4,5-dihydro-1H- pyrazol)-5-yl]-triphenylamine (Tris-5-DPP), was synthesized in a facile way, which can form amorphous thin films with glass transition temperature as high as 136 °C.
文摘Starburst triphenylamine molecules are generally used as hole transporting materials (HTMs)for optoelectronic devices like solar cells,light emitting diode and field effect transistors .The use of starburst triphenylamine molecules like spiro-OMeTAD HTM initiated the construction of solid state perovskite solar cells (PSCs).Currently,based on triphenylamine HTMs,the highest power conversion efficiency (PCE)of PSCs is up to 22.1%.
基金supported by the Ministry of Science and Technology of China(2014CB643501)the National Natural Science Foundation of China(51673069,91633301,21520102006,21761132001)+1 种基金Foundation of Guangzhou Science and Technology Project(201707020019,201607020010)the Pearl River S&T Nova Program of Guangzhou(201710010021)
文摘The polymer N2200, with its π-conjugated backbone composed of alternating naphthalene diimide(NDI) and bithiophene(DT)units, has been widely used as an acceptor for all-polymer solar cells(all-PSCs) owing to its high electron mobility and suitable ionization potential and electron affinity. Here, we developed two naphthalene diimide derivatives by modifying the molecular geometry of N2200 through the incorporation of a truxene unit as the core and NDI-DTas the branches. These starburst polymers exhibited absorption spectra and molecular orbital energy levels that were comparable to N2200. These copolymers were paired with the wide-bandgap polymer donor PTz BI-O to fabricate all-polymer solar cells(all-PSCs), which displayed impressive power conversion efficiencies up to 8.00%. The improved photovoltaic performances of all-PSCs based on these newly developed starburst acceptors can be ascribed to the combination of increased charge carrier mobilities, reduced bimolecular recombination, and formation of more favorable film morphology. These findings demonstrate that the construction of starburst polymer acceptors is a feasible strategy for the fabrication of high-performance all-PSCs.
文摘Two novel starburst compounds (star arylamines),4,4′,4″ tris(diphenylamino) triphenylamine (TDATA) and 4,4′,4″ tris[3 methyl (phenyl) amino] triphenylamine (MTDATA),were designed and synthesized as hole transport materials with high glass transition temperature ( t g),good film formation and film stability,excellent hole transporting ability.
