We conduct a statistical analysis of the hardness ratio(HR)for bright sources in the 4 yr Galactic Plane Scanning Survey catalog of Insight-HXMT.Depending on the stable(variable)flux F_(s)(F_(v))or spectrum S_(s)(S_(v...We conduct a statistical analysis of the hardness ratio(HR)for bright sources in the 4 yr Galactic Plane Scanning Survey catalog of Insight-HXMT.Depending on the stable(variable)flux F_(s)(F_(v))or spectrum S_(s)(S_(v))of each source,the bright sources are classified into three groups:F_(v)&S_(v),F_(v)&S_(s),and F_(s)&_(s).Our study of the HR characteristics in different types of sources reveals that accretion-powered neutron star(NS)low-mass X-ray binaries(LMXBs)exhibit softer energy spectra than NS high-mass X-ray binaries(HMXBs),but harder energy spectra than black hole binaries in most cases.This difference is probably due to their different magnetic field strengths.Additionally,Fv&Sv LMXBs tend to be harder than Fv&Ss LMXBs below 7 keV,while the opposite is true for HMXBs.Our results suggest that LMXBs may dominate unclassified sources,and NS binaries are likely to be the primary type of X-ray binaries with ambiguous compact stars.By comparing the HR of transient sources in their outburst and low-flux states,it is found that the averaged HR of four sources in the two states are roughly comparable within uncertainties.We also investigate the spatial properties of the three groups and find that Fv&Sv sources are mainly located in the longitude of-20°<l<9°,Fv&Ss sources cross the Galactic Plane,and Fs&Ss sources are predominantly concentrated in 19°<l<42°.In addition,analyzing the HR spatial distributions shows the absorption of soft X-rays(primarily below 2 keV)in the Galactic Plane.展开更多
In this study, we present a catalog of molecular clumps extracted from ^(13)CO(J=1-0) emission data of the Milky Way Imaging Scroll Painting(MWISP) project. The data covers the inner Milky Way within the longitude ran...In this study, we present a catalog of molecular clumps extracted from ^(13)CO(J=1-0) emission data of the Milky Way Imaging Scroll Painting(MWISP) project. The data covers the inner Milky Way within the longitude range10°≤l≤20° and the latitude strip of |b|≤ 5°. 25. The workflow for the extraction of clumps, namely Facet-SS-3DClump, consists of two parts: the identification of clump candidates and their verification. First, Facet-SS-3DClump employs FacetClumps to identify clump candidates. Subsequently, high-confidence clumps are obtained by cross-matching with the clumps detected by other algorithms, such as dendrogram. Second, these high-confidence clumps are used as prior knowledge to train a semi-supervised deep clustering approach, SS-3D-Clump, which is applied to verify clump candidates detected by FacetClumps, providing confidence levels for the molecular clumps. Finally, the catalog comprising 18,757 molecular clumps was obtained using Facet-SS-3D-Clump, and the catalog is 90% complete above 37 K km s^(-1). We observe a significant deviation of the mean Galactic latitude for clumps within |b|≤ 2° from the midplane, with b=-0°.110. We found that 82.3% of the dust clumps correspond to ^(13)CO clumps by matching with Herschel infrared dust clumps. In the future, Facet-SS-3D-Clump will be applied to detect ^(13)CO clumps in the entire MWISP data.展开更多
We present radial velocity(RV)curve templates of RR Lyrae first-overtone(RRc)stars constructed with the Mg I b triplet and Hαlines using time-domain Medium-Resolution Survey spectra of seven RRc stars from Large Sky ...We present radial velocity(RV)curve templates of RR Lyrae first-overtone(RRc)stars constructed with the Mg I b triplet and Hαlines using time-domain Medium-Resolution Survey spectra of seven RRc stars from Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST)Data Release 9.Additionally,we derive the relation between the stellar RV curve amplitudes and g-band light curve amplitudes from Zwicky Transient Facility(ZTF)public survey.For those RRc stars without ZTF g-band light curves,we provide the conversions from the light curve amplitudes in ZTF r-and i-bands,Gaia G-band,and V-band from the All-Sky Automated Survey for Supernovae to those in ZTF g-band.We validate our RV curve templates using the RRc star SV Scl and find the uncertainties of systemic RV are less than 2.11 km s~(-1)and 6.08 km s~(-1)based on the Mg I b triplet and Hαlines,respectively.We calculate the systemic RVs of 30 RRc stars using the RV curve templates constructed with the Mg I b triplet and Hαlines and find the systemic RVs are comparable with each other.This RV curve template will be particularly useful for obtaining the systemic RV of RRc using the LAMOST spectroscopy.展开更多
银河系光行差,或称为长期光行差漂移,是由于太阳系质心绕着银河系中心做轨道运动的加速度引起的视自行效应,量级大约为5μas·yr-1.在21世纪之前,由于观测精度尚未达到如此高的程度,人们很少讨论银河系光行差效应.随着甚长基线干涉(...银河系光行差,或称为长期光行差漂移,是由于太阳系质心绕着银河系中心做轨道运动的加速度引起的视自行效应,量级大约为5μas·yr-1.在21世纪之前,由于观测精度尚未达到如此高的程度,人们很少讨论银河系光行差效应.随着甚长基线干涉(Very Long Baseline Interferometer,VLBI)在基本天文学中的广泛应用和欧洲空间局(European Space Agency,ESA)的第2代微角秒天体测量卫星Gaia的问世,该效应显得逐渐重要.由于河外源的分布不均匀,银河系光行差效应会使得河外源天球参考架缓慢旋转,进而需要修正地球岁差参数,其中岁差速率的改正值大约为1μas·yr-1.对于微角秒精度的VLBI和Gaia参考架,银河系光行差将会引起框架扭曲,在两者的连接过程中,也是必须考虑的系统效应.展开更多
基金the support from the National Natural Science Foundation of China under grant Nos.12333007,U1838202,U1838201,U1838107,U1838113,U1838113 and U2038102the Youth Innovation Promotion Association of the CAS(grant id 2018014)+1 种基金the National Key R&D Program of China(grant No.2021YFA0718500)partially supported by the International Partnership Program of the Chinese Academy of Sciences(grant No.113111KYSB20190020)。
文摘We conduct a statistical analysis of the hardness ratio(HR)for bright sources in the 4 yr Galactic Plane Scanning Survey catalog of Insight-HXMT.Depending on the stable(variable)flux F_(s)(F_(v))or spectrum S_(s)(S_(v))of each source,the bright sources are classified into three groups:F_(v)&S_(v),F_(v)&S_(s),and F_(s)&_(s).Our study of the HR characteristics in different types of sources reveals that accretion-powered neutron star(NS)low-mass X-ray binaries(LMXBs)exhibit softer energy spectra than NS high-mass X-ray binaries(HMXBs),but harder energy spectra than black hole binaries in most cases.This difference is probably due to their different magnetic field strengths.Additionally,Fv&Sv LMXBs tend to be harder than Fv&Ss LMXBs below 7 keV,while the opposite is true for HMXBs.Our results suggest that LMXBs may dominate unclassified sources,and NS binaries are likely to be the primary type of X-ray binaries with ambiguous compact stars.By comparing the HR of transient sources in their outburst and low-flux states,it is found that the averaged HR of four sources in the two states are roughly comparable within uncertainties.We also investigate the spatial properties of the three groups and find that Fv&Sv sources are mainly located in the longitude of-20°<l<9°,Fv&Ss sources cross the Galactic Plane,and Fs&Ss sources are predominantly concentrated in 19°<l<42°.In addition,analyzing the HR spatial distributions shows the absorption of soft X-rays(primarily below 2 keV)in the Galactic Plane.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.U2031202,11903083,11873093 and 12203029)sponsored by National Key R&D Program of China with grant 2017YFA0402701 and CAS Key Research Program of Frontier Sciences with grant QYZDJ-SSW-SLH047。
文摘In this study, we present a catalog of molecular clumps extracted from ^(13)CO(J=1-0) emission data of the Milky Way Imaging Scroll Painting(MWISP) project. The data covers the inner Milky Way within the longitude range10°≤l≤20° and the latitude strip of |b|≤ 5°. 25. The workflow for the extraction of clumps, namely Facet-SS-3DClump, consists of two parts: the identification of clump candidates and their verification. First, Facet-SS-3DClump employs FacetClumps to identify clump candidates. Subsequently, high-confidence clumps are obtained by cross-matching with the clumps detected by other algorithms, such as dendrogram. Second, these high-confidence clumps are used as prior knowledge to train a semi-supervised deep clustering approach, SS-3D-Clump, which is applied to verify clump candidates detected by FacetClumps, providing confidence levels for the molecular clumps. Finally, the catalog comprising 18,757 molecular clumps was obtained using Facet-SS-3D-Clump, and the catalog is 90% complete above 37 K km s^(-1). We observe a significant deviation of the mean Galactic latitude for clumps within |b|≤ 2° from the midplane, with b=-0°.110. We found that 82.3% of the dust clumps correspond to ^(13)CO clumps by matching with Herschel infrared dust clumps. In the future, Facet-SS-3D-Clump will be applied to detect ^(13)CO clumps in the entire MWISP data.
基金supported by the National Key Research and Development Program of China(2023YFA1608100)the National Natural Science Foundation of China(NSFC,grant Nos.12090044,11833006 and 12303023)+3 种基金the science research grants from the China Manned Space Project including the CSST Milky Way and Nearby Galaxies Survey on Dust and Extinction Project CMS-CSST-2021-A09 and No.CMS-CSST-2021-A08.G.C.LHubei Provincial Natural Science Foundation with grant No.2023AFB577the Key Laboratory Fund of Ministry of Education under grant No.QLPL2022P01National Natural Science Foundation of China(NSFC,Grant No.U1731108)。
文摘We present radial velocity(RV)curve templates of RR Lyrae first-overtone(RRc)stars constructed with the Mg I b triplet and Hαlines using time-domain Medium-Resolution Survey spectra of seven RRc stars from Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST)Data Release 9.Additionally,we derive the relation between the stellar RV curve amplitudes and g-band light curve amplitudes from Zwicky Transient Facility(ZTF)public survey.For those RRc stars without ZTF g-band light curves,we provide the conversions from the light curve amplitudes in ZTF r-and i-bands,Gaia G-band,and V-band from the All-Sky Automated Survey for Supernovae to those in ZTF g-band.We validate our RV curve templates using the RRc star SV Scl and find the uncertainties of systemic RV are less than 2.11 km s~(-1)and 6.08 km s~(-1)based on the Mg I b triplet and Hαlines,respectively.We calculate the systemic RVs of 30 RRc stars using the RV curve templates constructed with the Mg I b triplet and Hαlines and find the systemic RVs are comparable with each other.This RV curve template will be particularly useful for obtaining the systemic RV of RRc using the LAMOST spectroscopy.
文摘银河系光行差,或称为长期光行差漂移,是由于太阳系质心绕着银河系中心做轨道运动的加速度引起的视自行效应,量级大约为5μas·yr-1.在21世纪之前,由于观测精度尚未达到如此高的程度,人们很少讨论银河系光行差效应.随着甚长基线干涉(Very Long Baseline Interferometer,VLBI)在基本天文学中的广泛应用和欧洲空间局(European Space Agency,ESA)的第2代微角秒天体测量卫星Gaia的问世,该效应显得逐渐重要.由于河外源的分布不均匀,银河系光行差效应会使得河外源天球参考架缓慢旋转,进而需要修正地球岁差参数,其中岁差速率的改正值大约为1μas·yr-1.对于微角秒精度的VLBI和Gaia参考架,银河系光行差将会引起框架扭曲,在两者的连接过程中,也是必须考虑的系统效应.
