This paper presents the results of a model analysis of optical spectra and determination of the parameters of three individual SU UMa and WZ Sge type dwarf novae.The moderate resolution spectra of TY Psc,FL Psc and V4...This paper presents the results of a model analysis of optical spectra and determination of the parameters of three individual SU UMa and WZ Sge type dwarf novae.The moderate resolution spectra of TY Psc,FL Psc and V455 And were obtained at the 6-m BTA of the SAO RAS in the low state of these systems with the determination of white dwarf radiation.The theoretical spectra were calculated using the grid models of hydrogen dwarf atmospheres of white dwarfs by varying the parameters(T_(eff) and log g) to reach the best agreement with the observed ones.We highlight different effects of the parameters on the shape and intensity of the HI lines.Therefore,it is possible to unambiguously determine T_(eff) and log g from the analysis of observations.The fundamental parameters of white dwarfs(M and R) were found by comparing the parameters of atmospheres with theoretical models of the internal structure.The obtained parameters of the primaries of TY Psc,FL Psc and V455 And are consistent with the average values for SU UMa and WZ Sge systems.As a result,we demonstrate the efficiency of the method for determining the parameters of such systems based on the analysis of a limited set of observed optical spectra.展开更多
We test the distance-duality （DD） relation by combining the angular diameter distance DA provided by two galaxy cluster samples compiled by De Filippis et al. （the elliptical β model） and Bonamente et al. （the s...We test the distance-duality （DD） relation by combining the angular diameter distance DA provided by two galaxy cluster samples compiled by De Filippis et al. （the elliptical β model） and Bonamente et al. （the spherical β model）, and the luminosity distance DL from Constitution and Union2 type Ia supernova （SNe Ia） datasets. To obtain DL associated with the observed DA at the same redshift, we smooth the noise of the SNe Ia in a model-independent way, obtain the evolutionary curve of DL and, finally, test the DD relation. We find that the elliptical β model, when compared with the SNe Ia from the Constitution compilation, is only consistent with the DD relation at the 3σ confidence level （CL）, while the spherical β model is incompatible with the DD relation at the 3σ CL. For the Union2 compilation, the De Filippis and Bonamente samples are marginally compatible with the validity of the DD relation at the 1σ and 2σ CLs, respectively.展开更多
We present the discovery of TCP J07222683+6220548,a new ultracompact binary system of the AM CVn type.This system was first identified displaying aΔV=7.6 mag outburst on 2025-01-20.9416 UTC by the New Milky Way wide-...We present the discovery of TCP J07222683+6220548,a new ultracompact binary system of the AM CVn type.This system was first identified displaying aΔV=7.6 mag outburst on 2025-01-20.9416 UTC by the New Milky Way wide-field survey for transients and later independently detected by ASAS-SN and ZTF.The outburst peaked at V_(max)=12.45 and lasted for seven days,followed by a series of rebrightenings.No previous outbursts are found in archival data.Positive superhumps with a period of 0.032546±0.000084 day(46.87±0.12 minutes),barely detectable during the main outburst,became clearly visible during the first rebrightening that lasted from day 18 to day 24 after the initial outburst.No convincing change in the superhump period was detected.Dense time-series photometry follow-up by a pair of 0.5 m INASAN robotic telescopes,together with VSNET and AAVSO observers,was essential for identifying TCP J07222683+6220548 as an AM CVn system and triggering confirmation spectroscopy with the 2.5 m CMO SAI telescope.Some outbursting AM CVn systems lacking such detailed follow-up may remain unrecognized among the newly discovered cataclysmic variable candidates.展开更多
This paper investigates the star formation efficiency(SFE)of blue compact galaxies(BCGs)by analyzing various indicators,including(O II),(H_(α)),infrared emissions,and the 1.4 GHz radio continuum.The assessment of SFE...This paper investigates the star formation efficiency(SFE)of blue compact galaxies(BCGs)by analyzing various indicators,including(O II),(H_(α)),infrared emissions,and the 1.4 GHz radio continuum.The assessment of SFE was conducted using publicly accessible data that concentrated on star formation rates(SFRs)and depletion timescales.By employing the fundamental equation,I determined the SFE in relation to its freefall time,which highlighted variations in efficiencies associated with SFR masses derived from different spectra.The results demonstrated that the highest efficiency value was observed in the analysis of the 1.4 GHz radio continuum,emphasizing the importance of studying star-forming clouds across a range of electromagnetic wavelengths to achieve a comprehensive understanding of star formation mechanisms.The study's findings indicated a peak efficiency of star formation value of approximately 0.9%,while the relative minimum obtained from(O II)was around 0.42%,aligning with the range of SFEs documented in the existing literature.Additionally,investigating the factors that influence the variability in efficiency when examining clouds in BCGs across different wave bands is crucial for deepening our comprehension of the underlying processes of star formation.展开更多
We have analyzed phase-resolved photometric and spectroscopic observations of the eclipsing polar SDSS J002637.06+242915.6.The light curve has a M-shaped bright phase that was reproduced using a simple model of an acc...We have analyzed phase-resolved photometric and spectroscopic observations of the eclipsing polar SDSS J002637.06+242915.6.The light curve has a M-shaped bright phase that was reproduced using a simple model of an accreting magnetic white dwarf.The hydrogen emission lines exhibit a narrow component formed on the irradiated hemisphere of the donor.The Doppler tomography revealed differences in the positions of emission regions of hydrogen and HeⅡλ4686 lines.The spectra exhibit a Zeeman absorption triplet of the Hαline,formed in the cold halo around the accretion spot at a magnetic field strength of B=15.1±1.3 MG.The spectra of the bright phase have a red cyclotron continuum,whose orbital variability has been interpreted within a simple model of an accretion spot.The modeling of the cyclotron continuum constrains the white dwarf's magnetic field to B_(cyc)■45 MG.The analysis of the eclipse light curve and the radial velocities of the irradiated hemisphere yielded estimates for the orbital inclination■,the mass ratio 0.23≤q≤0.43,and the white dwarf mass 0.72≥M_(1)/M_(⊙)≥0.42.展开更多
We present 17 cataclysmic variables(CVs) obtained from the crossmatch between the Sloan Digital Sky Survey(SDSS) and eROSITA Final Equatorial Depth Survey(eFEDS),including eight known CVs before eFEDS and nine identif...We present 17 cataclysmic variables(CVs) obtained from the crossmatch between the Sloan Digital Sky Survey(SDSS) and eROSITA Final Equatorial Depth Survey(eFEDS),including eight known CVs before eFEDS and nine identified from eFEDS.The photometric periods of four CVs are derived from the Zwicky Transient Facility and Catalina Real-Time Transient Survey.We focus on two CVs,SDSS J084309.3-014858 and SDSS J093555.0+042916,and confirm that their photometric periods correspond to the orbital periods by fitting the radial velocity curves.Furthermore,by the combination of the Gaia distance,the spectral energy distribution,and the variations of Ha emission lines,the masses of the white dwarf and the visible star can be well constrained.展开更多
Novae are found to have GeV to TeVγ-ray emission,which reveals the shock acceleration from the white dwarfs.Recently,V1405 Cas was reported to radiate suspiciousγ-ray by Fermi-LAT with low signi?cance(4.1σ)after th...Novae are found to have GeV to TeVγ-ray emission,which reveals the shock acceleration from the white dwarfs.Recently,V1405 Cas was reported to radiate suspiciousγ-ray by Fermi-LAT with low signi?cance(4.1σ)after the optical maximum.Radio observations reveal that it is one of the?ve brightest novae surrounded by low-density ionized gas columns.Here we report a continuous search for GeVγ-ray from Fermi-LAT.Noγ-ray was found.For V1405 Cas the?ux level is lower than other well-studied Fermi novae,and theγ-ray maximum appears at t0+145 days.γ-ray of V1405 Cas is used to search potentialγ-ray periodicity.Noγ-ray periodicity was found during the time of observation.By comparing multi-wavelength data,theγ-ray upper limit to optical?ux ratio with a value at around 10^(-4)is obtained to constrain the shock acceleration.Long-term analysis from Swift-XRT gets X-ray spectral in the post-shock phase,which indicates that V1405 Cas became a super-soft source.The best-?t black body temperature at the super soft state is 0.11-0.19 keV.展开更多
In this paper,we perform the detailed modeling for the light curves(LCs)of PTF 10iuv which is a calcium-rich(Ca-rich)supernova(SN)to constrain the physical properties of its ejecta and the energy sources,as well as th...In this paper,we perform the detailed modeling for the light curves(LCs)of PTF 10iuv which is a calcium-rich(Ca-rich)supernova(SN)to constrain the physical properties of its ejecta and the energy sources,as well as the explosion mechanism.We find that the^(56)Ni model and the56Ni plus circumstellar interaction model fail to explain the LCs,while the four-element(^(56)Ni,^(48)Cr,^(52)Fe,and^(44)Ti)model can account for the LCs.The ejecta mass of PTF10iuv derived by the model(1.52_(-0.25)^(+0.34)M_(⊙))is consistent with that of the merger of a sub-Chandrasekhar mass white dwarf.The early-time LCs were mainly powered by^(56)Ni whose mass is~0.03 M_(⊙),while the contributions of^(48)Cr and^(52)Fe can be neglected.The derived^(44)Ti mass(~0.25 M_(⊙))is~1.8 times the upper limit of the derived^(44)Ti mass of Ca-rich SN 2005E.We suggest that subtracting the contributions of the host-galaxy,which are unknown,and including the flux from other long-lived elements(e.g.,^(57)Co,^(55)Fe,^(60)Co)can reduce the amount of^(44)Ti,and that this value can be regarded as an upper limit.展开更多
In March 2025,the Cellulose Fibers Conference 2025,hosted by nova-Institute,a leading independent research institute in the field of global biotechnology,was held in Cologne,Germany.The conference presented the most s...In March 2025,the Cellulose Fibers Conference 2025,hosted by nova-Institute,a leading independent research institute in the field of global biotechnology,was held in Cologne,Germany.The conference presented the most successful solutions based on cellulose fibers that are currently available on the market,new developments and approaches and also shed light on the policy framework.展开更多
此前,我们曾到域丰音响位于广州番禺的陈列室中试听了naim最新推出的Uriiti Nova PE多功能一体机搭配Focal的Scala Utopia Evo落地式音箱,这套系统让笔者体验到了Uniti Nova PE的强劲推力,毕竟搭配Scala Utopia Evo属于越级挑战了。文...此前,我们曾到域丰音响位于广州番禺的陈列室中试听了naim最新推出的Uriiti Nova PE多功能一体机搭配Focal的Scala Utopia Evo落地式音箱,这套系统让笔者体验到了Uniti Nova PE的强劲推力,毕竟搭配Scala Utopia Evo属于越级挑战了。文章发布后也有读者朋友留言问到,naim Uniti Nova PE搭配和其价格相仿的Focal Sopra N°2会不会更好?于是我们再次来到域丰音响的试音室,试听这套系统的搭配。展开更多
We report on time-resolved spectroscopic observations of the SU Ursae Majoris dwarf nova, YZ Cnc for over llh on two nights during its 2002 January superoutburst. The spectra on the first day only showed absorption-li...We report on time-resolved spectroscopic observations of the SU Ursae Majoris dwarf nova, YZ Cnc for over llh on two nights during its 2002 January superoutburst. The spectra on the first day only showed absorption-line profiles, while on the second day the lines showed “W” profiles with blue and red troughs. The radial velocity curve of the absorption troughs and emission peaks of H/3 has an amplitude of 49±10 km s^-1 and a phase offset of -0.07±0.04, which are very similar to those measured in quiescence. However, the γ velocity deviates strongly from the systemic velocity measured in quiescence, by some ±60 km s^-1. Large shifts of -70 km s^-1 in the orbital-averaged velocity and -0.09 in the phase are also found in our observations. All these features can be well explained by a precessing, eccentric disk.展开更多
In this study,we present an investigation of the newly discovered dwarf nova ASASSN-19oc during its superoutburst on 2019 June 2.We carried out detailed UBVRcIc-photometric observations and also obtained a spectrum on...In this study,we present an investigation of the newly discovered dwarf nova ASASSN-19oc during its superoutburst on 2019 June 2.We carried out detailed UBVRcIc-photometric observations and also obtained a spectrum on day 7 of the outburst,which shows the presence of hydrogen absorption lines commonly found in dwarf nova outbursts.Analysis of photometric data reveals the occurrence of early superhumps in the initial days of observations,followed by ordinary and late superhumps.We have accurately calculated the period of the ordinary superhumps as Pord=0.05681(10)days and determined the periods at different stages,as well as the rate of change of the superhump period(P_(dot)=(5)P/P=8.1×10^(-5)).Additionally,we have derived the mass ratio of the components(q=0.09),and estimated the color temperature during the outburst as~11,000 K,the distance to the system(d=560 pc)and absolute magnitude of the system in outburst(MV=5.3).We have shown that outbursts of this star are very rare:based on brightness measurements on 600 archival photographic plates,we found only one outburst that occurred in 1984.This fact,as well as the properties listed above,convincingly shows that the variable ASASSN-19oc is a dwarf nova of WZ Sge type.展开更多
介绍了基于GE Nova Sensor公司新型NPX系列芯片的轮胎压力监控系统,给出了系统硬件构成、相关软件流程和通信设计参考。该系统用于在汽车行驶过程中监控轮胎状态,如果出现压力和温度的异常变化,可实时报警,从而有效地避免因爆胎引起交...介绍了基于GE Nova Sensor公司新型NPX系列芯片的轮胎压力监控系统,给出了系统硬件构成、相关软件流程和通信设计参考。该系统用于在汽车行驶过程中监控轮胎状态,如果出现压力和温度的异常变化,可实时报警,从而有效地避免因爆胎引起交通事故。展开更多
目前电厂烟囱变形监测主要利用传统测量或GPS技术,通过布置监测点达到监测的目的。但传统的监测方法容易受场地、天气、温度及风力等因素的影响,且观测周期较长。为此,进行快速高精度及无接触变形监测成为研究的热点。本文利用Leica Nov...目前电厂烟囱变形监测主要利用传统测量或GPS技术,通过布置监测点达到监测的目的。但传统的监测方法容易受场地、天气、温度及风力等因素的影响,且观测周期较长。为此,进行快速高精度及无接触变形监测成为研究的热点。本文利用Leica Nova MS50全站扫描仪高速点云扫描、高分辨率图像采集及长距离免棱镜测距的功能,进行烟囱倾斜及挠度变化的监测分析。展开更多
基金supported by the Ministry of Science and Higher Education of the Russian Federationfinancial support from the RFBR and the Government of the RT in the framework of scientific projects 18–42–160003funded by the subsidy 671–2020–0052 allocated to KFU for assignment in scientific activities。
文摘This paper presents the results of a model analysis of optical spectra and determination of the parameters of three individual SU UMa and WZ Sge type dwarf novae.The moderate resolution spectra of TY Psc,FL Psc and V455 And were obtained at the 6-m BTA of the SAO RAS in the low state of these systems with the determination of white dwarf radiation.The theoretical spectra were calculated using the grid models of hydrogen dwarf atmospheres of white dwarfs by varying the parameters(T_(eff) and log g) to reach the best agreement with the observed ones.We highlight different effects of the parameters on the shape and intensity of the HI lines.Therefore,it is possible to unambiguously determine T_(eff) and log g from the analysis of observations.The fundamental parameters of white dwarfs(M and R) were found by comparing the parameters of atmospheres with theoretical models of the internal structure.The obtained parameters of the primaries of TY Psc,FL Psc and V455 And are consistent with the average values for SU UMa and WZ Sge systems.As a result,we demonstrate the efficiency of the method for determining the parameters of such systems based on the analysis of a limited set of observed optical spectra.
基金Supported by the National Natural Science Foundation of China(Grants Nos. 10935013 and 11075083)the Zhejiang Provincial Natural Science Foundation of China under Grant No. Z6100077+3 种基金the FANEDD under Grant No. 200922the National Basic Research Program of China (Grant No. 2010CB832803)the NCET under Grant No. 09-0144the PCSIRT under Grant No. IRT0964
文摘We test the distance-duality （DD） relation by combining the angular diameter distance DA provided by two galaxy cluster samples compiled by De Filippis et al. （the elliptical β model） and Bonamente et al. （the spherical β model）, and the luminosity distance DL from Constitution and Union2 type Ia supernova （SNe Ia） datasets. To obtain DL associated with the observed DA at the same redshift, we smooth the noise of the SNe Ia in a model-independent way, obtain the evolutionary curve of DL and, finally, test the DD relation. We find that the elliptical β model, when compared with the SNe Ia from the Constitution compilation, is only consistent with the DD relation at the 3σ confidence level （CL）, while the spherical β model is incompatible with the DD relation at the 3σ CL. For the Union2 compilation, the De Filippis and Bonamente samples are marginally compatible with the validity of the DD relation at the 1σ and 2σ CLs, respectively.
基金support of the Foundation for the Development of Theoretical Physics and Mathematics BASIS(project 24-2-1-6-1)supported by the UKRI Science and Technology Facilities Council and is a collaboration between the University of Edinburgh(grant ST/N002512/1)and Queen’s University Belfast(grant ST/N002520/1)within the LSST:UK Science Consortium+4 种基金supported by the National Science Foundation under grants No.AST-1440341 and AST-2034437primarily funded to search for near earth asteroids through NASA grants NN12AR55G,80NSSC18K0284,and80NSSC18K1575partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889STFC grants ST/T000198/1 and ST/S006109/1made use of the Astrophysics Data System,funded by NASA under Cooperative Agreement 80NSSC21M00561。
文摘We present the discovery of TCP J07222683+6220548,a new ultracompact binary system of the AM CVn type.This system was first identified displaying aΔV=7.6 mag outburst on 2025-01-20.9416 UTC by the New Milky Way wide-field survey for transients and later independently detected by ASAS-SN and ZTF.The outburst peaked at V_(max)=12.45 and lasted for seven days,followed by a series of rebrightenings.No previous outbursts are found in archival data.Positive superhumps with a period of 0.032546±0.000084 day(46.87±0.12 minutes),barely detectable during the main outburst,became clearly visible during the first rebrightening that lasted from day 18 to day 24 after the initial outburst.No convincing change in the superhump period was detected.Dense time-series photometry follow-up by a pair of 0.5 m INASAN robotic telescopes,together with VSNET and AAVSO observers,was essential for identifying TCP J07222683+6220548 as an AM CVn system and triggering confirmation spectroscopy with the 2.5 m CMO SAI telescope.Some outbursting AM CVn systems lacking such detailed follow-up may remain unrecognized among the newly discovered cataclysmic variable candidates.
文摘This paper investigates the star formation efficiency(SFE)of blue compact galaxies(BCGs)by analyzing various indicators,including(O II),(H_(α)),infrared emissions,and the 1.4 GHz radio continuum.The assessment of SFE was conducted using publicly accessible data that concentrated on star formation rates(SFRs)and depletion timescales.By employing the fundamental equation,I determined the SFE in relation to its freefall time,which highlighted variations in efficiencies associated with SFR masses derived from different spectra.The results demonstrated that the highest efficiency value was observed in the analysis of the 1.4 GHz radio continuum,emphasizing the importance of studying star-forming clouds across a range of electromagnetic wavelengths to achieve a comprehensive understanding of star formation mechanisms.The study's findings indicated a peak efficiency of star formation value of approximately 0.9%,while the relative minimum obtained from(O II)was around 0.42%,aligning with the range of SFEs documented in the existing literature.Additionally,investigating the factors that influence the variability in efficiency when examining clouds in BCGs across different wave bands is crucial for deepening our comprehension of the underlying processes of star formation.
基金supported by the Ministry of Science and Higher Education of the Russian Federation。
文摘We have analyzed phase-resolved photometric and spectroscopic observations of the eclipsing polar SDSS J002637.06+242915.6.The light curve has a M-shaped bright phase that was reproduced using a simple model of an accreting magnetic white dwarf.The hydrogen emission lines exhibit a narrow component formed on the irradiated hemisphere of the donor.The Doppler tomography revealed differences in the positions of emission regions of hydrogen and HeⅡλ4686 lines.The spectra exhibit a Zeeman absorption triplet of the Hαline,formed in the cold halo around the accretion spot at a magnetic field strength of B=15.1±1.3 MG.The spectra of the bright phase have a red cyclotron continuum,whose orbital variability has been interpreted within a simple model of an accretion spot.The modeling of the cyclotron continuum constrains the white dwarf's magnetic field to B_(cyc)■45 MG.The analysis of the eclipse light curve and the radial velocities of the irradiated hemisphere yielded estimates for the orbital inclination■,the mass ratio 0.23≤q≤0.43,and the white dwarf mass 0.72≥M_(1)/M_(⊙)≥0.42.
基金supported by the National Key R&D Program of China under grants 2023YFA1607901 and 2021YFA1600401the National Natural Science Foundation of China under grants 12433007, 11925301, 12033006, 12221003, and 12263003+1 种基金the fellowship of China National Postdoctoral Program for Innovation Talents under grant BX20230020the science research grants from the China Manned Space Project with No. CMS-CSST-2025-A13。
文摘We present 17 cataclysmic variables(CVs) obtained from the crossmatch between the Sloan Digital Sky Survey(SDSS) and eROSITA Final Equatorial Depth Survey(eFEDS),including eight known CVs before eFEDS and nine identified from eFEDS.The photometric periods of four CVs are derived from the Zwicky Transient Facility and Catalina Real-Time Transient Survey.We focus on two CVs,SDSS J084309.3-014858 and SDSS J093555.0+042916,and confirm that their photometric periods correspond to the orbital periods by fitting the radial velocity curves.Furthermore,by the combination of the Gaia distance,the spectral energy distribution,and the variations of Ha emission lines,the masses of the white dwarf and the visible star can be well constrained.
基金supported by the National Natural Science Foundation of China(NSFC,grant No.12393853)the Scientific Research Foundation of Hunan Provincial Education Department(21C0343)+1 种基金the Science Research Project of the University(Youth Project)of the Department of Education of Guizhou Province(QJJ[2022]348)the Science and Technology Foundation of Guizhou Province(QKHJC-ZK[2023]442)。
文摘Novae are found to have GeV to TeVγ-ray emission,which reveals the shock acceleration from the white dwarfs.Recently,V1405 Cas was reported to radiate suspiciousγ-ray by Fermi-LAT with low signi?cance(4.1σ)after the optical maximum.Radio observations reveal that it is one of the?ve brightest novae surrounded by low-density ionized gas columns.Here we report a continuous search for GeVγ-ray from Fermi-LAT.Noγ-ray was found.For V1405 Cas the?ux level is lower than other well-studied Fermi novae,and theγ-ray maximum appears at t0+145 days.γ-ray of V1405 Cas is used to search potentialγ-ray periodicity.Noγ-ray periodicity was found during the time of observation.By comparing multi-wavelength data,theγ-ray upper limit to optical?ux ratio with a value at around 10^(-4)is obtained to constrain the shock acceleration.Long-term analysis from Swift-XRT gets X-ray spectral in the post-shock phase,which indicates that V1405 Cas became a super-soft source.The best-?t black body temperature at the super soft state is 0.11-0.19 keV.
基金supported by National Natural Science Foundation of China(NSFC,grant Nos.11963001,12133003,11833003,11973020(C0035736),and U1938201)supported by the Guangxi Talent Program(“Highland of Innovation Talents”)。
文摘In this paper,we perform the detailed modeling for the light curves(LCs)of PTF 10iuv which is a calcium-rich(Ca-rich)supernova(SN)to constrain the physical properties of its ejecta and the energy sources,as well as the explosion mechanism.We find that the^(56)Ni model and the56Ni plus circumstellar interaction model fail to explain the LCs,while the four-element(^(56)Ni,^(48)Cr,^(52)Fe,and^(44)Ti)model can account for the LCs.The ejecta mass of PTF10iuv derived by the model(1.52_(-0.25)^(+0.34)M_(⊙))is consistent with that of the merger of a sub-Chandrasekhar mass white dwarf.The early-time LCs were mainly powered by^(56)Ni whose mass is~0.03 M_(⊙),while the contributions of^(48)Cr and^(52)Fe can be neglected.The derived^(44)Ti mass(~0.25 M_(⊙))is~1.8 times the upper limit of the derived^(44)Ti mass of Ca-rich SN 2005E.We suggest that subtracting the contributions of the host-galaxy,which are unknown,and including the flux from other long-lived elements(e.g.,^(57)Co,^(55)Fe,^(60)Co)can reduce the amount of^(44)Ti,and that this value can be regarded as an upper limit.
文摘In March 2025,the Cellulose Fibers Conference 2025,hosted by nova-Institute,a leading independent research institute in the field of global biotechnology,was held in Cologne,Germany.The conference presented the most successful solutions based on cellulose fibers that are currently available on the market,new developments and approaches and also shed light on the policy framework.
文摘此前,我们曾到域丰音响位于广州番禺的陈列室中试听了naim最新推出的Uriiti Nova PE多功能一体机搭配Focal的Scala Utopia Evo落地式音箱,这套系统让笔者体验到了Uniti Nova PE的强劲推力,毕竟搭配Scala Utopia Evo属于越级挑战了。文章发布后也有读者朋友留言问到,naim Uniti Nova PE搭配和其价格相仿的Focal Sopra N°2会不会更好?于是我们再次来到域丰音响的试音室,试听这套系统的搭配。
基金Supported by the National Natural Science Foundation of China.
文摘We report on time-resolved spectroscopic observations of the SU Ursae Majoris dwarf nova, YZ Cnc for over llh on two nights during its 2002 January superoutburst. The spectra on the first day only showed absorption-line profiles, while on the second day the lines showed “W” profiles with blue and red troughs. The radial velocity curve of the absorption troughs and emission peaks of H/3 has an amplitude of 49±10 km s^-1 and a phase offset of -0.07±0.04, which are very similar to those measured in quiescence. However, the γ velocity deviates strongly from the systemic velocity measured in quiescence, by some ±60 km s^-1. Large shifts of -70 km s^-1 in the orbital-averaged velocity and -0.09 in the phase are also found in our observations. All these features can be well explained by a precessing, eccentric disk.
基金financial support of the APVV-20-0148,VEGA 2/0030/21 and VEGA 2/0031/22grantssupport from the Government Office of the Slovak Republic within EU NextGenerationEU through the Recovery and Resilience Plan for Slovakia under the project No.09I03-03-V01-00002the private company 4pi Systeme GmbH for partial sponsorship。
文摘In this study,we present an investigation of the newly discovered dwarf nova ASASSN-19oc during its superoutburst on 2019 June 2.We carried out detailed UBVRcIc-photometric observations and also obtained a spectrum on day 7 of the outburst,which shows the presence of hydrogen absorption lines commonly found in dwarf nova outbursts.Analysis of photometric data reveals the occurrence of early superhumps in the initial days of observations,followed by ordinary and late superhumps.We have accurately calculated the period of the ordinary superhumps as Pord=0.05681(10)days and determined the periods at different stages,as well as the rate of change of the superhump period(P_(dot)=(5)P/P=8.1×10^(-5)).Additionally,we have derived the mass ratio of the components(q=0.09),and estimated the color temperature during the outburst as~11,000 K,the distance to the system(d=560 pc)and absolute magnitude of the system in outburst(MV=5.3).We have shown that outbursts of this star are very rare:based on brightness measurements on 600 archival photographic plates,we found only one outburst that occurred in 1984.This fact,as well as the properties listed above,convincingly shows that the variable ASASSN-19oc is a dwarf nova of WZ Sge type.
文摘目前电厂烟囱变形监测主要利用传统测量或GPS技术,通过布置监测点达到监测的目的。但传统的监测方法容易受场地、天气、温度及风力等因素的影响,且观测周期较长。为此,进行快速高精度及无接触变形监测成为研究的热点。本文利用Leica Nova MS50全站扫描仪高速点云扫描、高分辨率图像采集及长距离免棱镜测距的功能,进行烟囱倾斜及挠度变化的监测分析。
