Marin Treselj, A. Seifahrt, K. Hodapp, A. Bedalov, M. Mugrauer
We present the first results of a large imaging survey to identify wide brown dwarf companions to stars within 10 pc. We have performed a deep (H‐band limit ∼19.0 mag), wide field (up to 16×16 arcmin) astrometric imaging campaign in two epochs around more than 230 nearby stars.Preliminary results show that the wide low‐mass companion fraction is far lower than expected, indicating that interactions with the galactic disk may have removed the weakly bound wide companions around old stars.
{"title":"A search for wide brown dwarf companions to stars within 10 pc","authors":"Marin Treselj, A. Seifahrt, K. Hodapp, A. Bedalov, M. Mugrauer","doi":"10.1063/1.3099175","DOIUrl":"https://doi.org/10.1063/1.3099175","url":null,"abstract":"We present the first results of a large imaging survey to identify wide brown dwarf companions to stars within 10 pc. We have performed a deep (H‐band limit ∼19.0 mag), wide field (up to 16×16 arcmin) astrometric imaging campaign in two epochs around more than 230 nearby stars.Preliminary results show that the wide low‐mass companion fraction is far lower than expected, indicating that interactions with the galactic disk may have removed the weakly bound wide companions around old stars.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82485898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Seifahrt, C. Helling, A. Burgasser, K. Allers, K. Cruz, M. Cushing, U. Heiter, D. Looper, S. Witte
Observational facilities allow now the detection of optical and IR spectra of young M‐ and L‐dwarfs. This enables empirical comparisons with old M‐ and L‐ dwarfs, and detailed studies in comparison with synthetic spectra. While classical stellar atmosphere physics seems perfectly appropriate for old M‐dwarfs, more physical and chemical processes, cloud formation in particular, needs to be modelled in the substellar regime to allow a detailed spectral interpretation. Not much is known so far about the details of the inset of cloud formation at the spectral transition region between M and L dwarfs. Furthermore there is observational evidence for diversity in the dust properties of objects having the same spectral type. Do we understand these differences? The question is also how young M‐ and L‐dwarfs need to be classified, which stellar parameter do they have and whether degenerations in the stellar parameter space due to the changing atmosphere physics are present, like in the L‐T transition region. The Splinter was driven by these questions which we will use to encourage interactions between observation and theory. Given the recent advances, both in observations and spectral modelling, an intensive discussion between observers and theoreticians will create new synergies in our field.
{"title":"Observation and modelling of dusty, low gravity L, and M dwarfs","authors":"A. Seifahrt, C. Helling, A. Burgasser, K. Allers, K. Cruz, M. Cushing, U. Heiter, D. Looper, S. Witte","doi":"10.1063/1.3099103","DOIUrl":"https://doi.org/10.1063/1.3099103","url":null,"abstract":"Observational facilities allow now the detection of optical and IR spectra of young M‐ and L‐dwarfs. This enables empirical comparisons with old M‐ and L‐ dwarfs, and detailed studies in comparison with synthetic spectra. While classical stellar atmosphere physics seems perfectly appropriate for old M‐dwarfs, more physical and chemical processes, cloud formation in particular, needs to be modelled in the substellar regime to allow a detailed spectral interpretation. \u0000 \u0000Not much is known so far about the details of the inset of cloud formation at the spectral transition region between M and L dwarfs. Furthermore there is observational evidence for diversity in the dust properties of objects having the same spectral type. Do we understand these differences? The question is also how young M‐ and L‐dwarfs need to be classified, which stellar parameter do they have and whether degenerations in the stellar parameter space due to the changing atmosphere physics are present, like in the L‐T transition region. \u0000 \u0000The Splinter was driven by these questions which we will use to encourage interactions between observation and theory. Given the recent advances, both in observations and spectral modelling, an intensive discussion between observers and theoreticians will create new synergies in our field.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91238258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present first results from a multi‐object spectroscopy campaign in IC2602, the Hyades, the Pleiades, and the Coma cluster using VLT/FLAMES. We analysed the data for radial velocity, rotational velocity (v sin i), and Hα‐activity. Here, we highlight three aspects of this study in the context of rotational braking and the rotation‐activity relationship among low mass stars. Finally we discuss the cluster membership of sources in IC2602.
我们展示了使用VLT/ flame对IC2602、星团、昴宿星团和后发星团进行的多目标光谱活动的第一批结果。我们分析了径向速度、旋转速度(v sin i)和Hα活性的数据。在这里，我们重点介绍了本研究在旋转制动和低质量恒星旋转活动关系背景下的三个方面。最后讨论了IC2602中源的集群隶属关系。
{"title":"Activity and rotation of low mass stars in young open clusters","authors":"A. Seifahrt, A. Reiners, A. Scholz, G. Basri","doi":"10.1063/1.3099123","DOIUrl":"https://doi.org/10.1063/1.3099123","url":null,"abstract":"We present first results from a multi‐object spectroscopy campaign in IC2602, the Hyades, the Pleiades, and the Coma cluster using VLT/FLAMES. We analysed the data for radial velocity, rotational velocity (v sin i), and Hα‐activity. Here, we highlight three aspects of this study in the context of rotational braking and the rotation‐activity relationship among low mass stars. Finally we discuss the cluster membership of sources in IC2602.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72919313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The combination of two‐dimensional kinematics and gravitational lens modelling permits detailed reconstruction of the phase‐space structure of early‐type galaxies and sets constraints on the dark‐matter distribution in their inner regions. We describe a project which combines integral‐field spectroscopy from an ESO Large Programme using VIMOS on the VLT with deep HST ACS and NICMOS images to study a sample of 17 early‐type lens galaxies at z≈0.1–0.3, drawn from the Sloan Lens ACS survey (SLACS).
{"title":"Integral-Field Spectroscopy of SLACS Lenses","authors":"O. Czoske, M. Barnabè, L. Koopmans","doi":"10.1063/1.3141531","DOIUrl":"https://doi.org/10.1063/1.3141531","url":null,"abstract":"The combination of two‐dimensional kinematics and gravitational lens modelling permits detailed reconstruction of the phase‐space structure of early‐type galaxies and sets constraints on the dark‐matter distribution in their inner regions. We describe a project which combines integral‐field spectroscopy from an ESO Large Programme using VIMOS on the VLT with deep HST ACS and NICMOS images to study a sample of 17 early‐type lens galaxies at z≈0.1–0.3, drawn from the Sloan Lens ACS survey (SLACS).","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88008430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-11-14DOI: 10.1007/978-3-540-76935-4_9
D. Jewitt
{"title":"Six Hot Topics in Planetary Astronomy","authors":"D. Jewitt","doi":"10.1007/978-3-540-76935-4_9","DOIUrl":"https://doi.org/10.1007/978-3-540-76935-4_9","url":null,"abstract":"","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88226541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-11-13DOI: 10.1007/978-1-4020-8868-1_17
B. Mukhopadhyay
{"title":"Transonic Properties of Accretion Disk Around Compact Objects","authors":"B. Mukhopadhyay","doi":"10.1007/978-1-4020-8868-1_17","DOIUrl":"https://doi.org/10.1007/978-1-4020-8868-1_17","url":null,"abstract":"","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80681415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present two models for the cosmological UV background light, and calculate the opacity of GeV gamma—rays out to redshift 9. The contributors to the background include 2 possible quasar emissivities, and output from star—forming galaxies as determined by recent a semi—analytic model (SAM) of structure formation. The SAM used in this work is based upon a hierarchical build‐up of structure in a ΛCDM universe and is highly successful in reproducing a variety of observational parameters. Above 1 Rydberg energy, ionizing radiation is subject to reprocessing by the IGM, which we treat using our radiative transfer code, CUBA. The two models for quasar emissivity differing above z = 2.3 are chosen to match the ionization rates observed using flux decrement analysis and the higher values of the line‐of‐sight proximity effect. We also investigate the possibility of aflat star formation rate density at z>5. We conclude that observations of gamma—rays from 10 to 100 GeV by Fermi (GLAST) and the next generation of g...
{"title":"Modeling Gamma‐Ray Attenuation in High Redshift GeV Spectra","authors":"R. Gilmore, P. Madau, J. Primack, R. Somerville","doi":"10.1063/1.3076738","DOIUrl":"https://doi.org/10.1063/1.3076738","url":null,"abstract":"We present two models for the cosmological UV background light, and calculate the opacity of GeV gamma—rays out to redshift 9. The contributors to the background include 2 possible quasar emissivities, and output from star—forming galaxies as determined by recent a semi—analytic model (SAM) of structure formation. The SAM used in this work is based upon a hierarchical build‐up of structure in a ΛCDM universe and is highly successful in reproducing a variety of observational parameters. Above 1 Rydberg energy, ionizing radiation is subject to reprocessing by the IGM, which we treat using our radiative transfer code, CUBA. The two models for quasar emissivity differing above z = 2.3 are chosen to match the ionization rates observed using flux decrement analysis and the higher values of the line‐of‐sight proximity effect. We also investigate the possibility of aflat star formation rate density at z>5. We conclude that observations of gamma—rays from 10 to 100 GeV by Fermi (GLAST) and the next generation of g...","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77952652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-11-12DOI: 10.1088/0004-637X/693/1/750
R. Bussmann, A. Dey, J. Lotz, L. Armus, K. Brand, Michael J. I. Brown, V. Desai, P. Eisenhardt, J. Higdon, S. Higdon, B. Jannuzi, E. Floc’h, J. Melbourne, B. Soifer, D. Weedman
We present high spatial resolution optical and near-infrared imaging obtained using the ACS, WFPC2 and NICMOS cameras aboard the Hubble Space Telescope of 31 24um--bright z~2 Dust Obscured Galaxies (DOGs) identified in the Bootes Field of the NOAO Deep Wide-Field Survey. Although this subset of DOGs have mid-IR spectral energy distributions dominated by a power-law component suggestive of an AGN, all but one of the galaxies are spatially extended and not dominated by an unresolved component at rest-frame UV or optical wavelengths. The observed V-H and I-H colors of the extended components are 0.2-3 magnitudes redder than normal star-forming galaxies. All but 1 have axial ratios >0.3, making it unlikely that DOGs are composed of an edge-on star-forming disk. We model the spatially extended component of the surface brightness distributions of the DOGs with a Sersic profile and find effective radii of 1-6 kpc. This sample of DOGs is smaller than most sub-millimeter galaxies (SMGs), but larger than quiescent high-redshift galaxies. Non-parametric measures (Gini and M20) of DOG morphologies suggest that these galaxies are more dynamically relaxed than local ULIRGs. We estimate lower limits to the stellar masses of DOGs based on the rest-frame optical photometry and find that these range from ~10^(9-11) M_sun. If major mergers are the progenitors of DOGs, then these observations suggest that DOGs may represent a post-merger evolutionary stage.
{"title":"HST Morphologies of z~2 Dust Obscured Galaxies I: Power-law Sources","authors":"R. Bussmann, A. Dey, J. Lotz, L. Armus, K. Brand, Michael J. I. Brown, V. Desai, P. Eisenhardt, J. Higdon, S. Higdon, B. Jannuzi, E. Floc’h, J. Melbourne, B. Soifer, D. Weedman","doi":"10.1088/0004-637X/693/1/750","DOIUrl":"https://doi.org/10.1088/0004-637X/693/1/750","url":null,"abstract":"We present high spatial resolution optical and near-infrared imaging obtained using the ACS, WFPC2 and NICMOS cameras aboard the Hubble Space Telescope of 31 24um--bright z~2 Dust Obscured Galaxies (DOGs) identified in the Bootes Field of the NOAO Deep Wide-Field Survey. Although this subset of DOGs have mid-IR spectral energy distributions dominated by a power-law component suggestive of an AGN, all but one of the galaxies are spatially extended and not dominated by an unresolved component at rest-frame UV or optical wavelengths. The observed V-H and I-H colors of the extended components are 0.2-3 magnitudes redder than normal star-forming galaxies. All but 1 have axial ratios >0.3, making it unlikely that DOGs are composed of an edge-on star-forming disk. We model the spatially extended component of the surface brightness distributions of the DOGs with a Sersic profile and find effective radii of 1-6 kpc. This sample of DOGs is smaller than most sub-millimeter galaxies (SMGs), but larger than quiescent high-redshift galaxies. Non-parametric measures (Gini and M20) of DOG morphologies suggest that these galaxies are more dynamically relaxed than local ULIRGs. We estimate lower limits to the stellar masses of DOGs based on the rest-frame optical photometry and find that these range from ~10^(9-11) M_sun. If major mergers are the progenitors of DOGs, then these observations suggest that DOGs may represent a post-merger evolutionary stage.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82280489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
LS 5039 is a TeV gamma-ray binary with extended radio emission. It consists of a compact object in the mildly eccentric (e=0.35), 3.9-day orbit around a massive O star. The nature of the compact object is not yet established. In this paper, assuming that the compact object is a black hole, we study the accretion of O-star wind by the black hole, by performing three-dimensional Smoothed Particle Hydrodynamics (SPH) simulations. In order to roughly emulate the effect of the stellar radiation effectively canceling the stellar gravity, we assume that the O star's gravity does not exert on the wind. The wind particles are ejected with half the observed terminal velocity in a narrow range of azimuthal and vertical angles toward the black hole, in order to emulate the wind significantly slower than the terminal speed, and optimize the resolution and computational efficiency of simulations. We find that the mass-accretion rate closely follows the classical Bondi-Hoyle-Littleton accretion rate, which is of the order of 10^{16}g/s around periastron. The accretion rate at this level would provide jets enough power to produce the gamma-rays detected by HESS. Since the accretion peak occurs near the periastron passage, we need a strong gamma-ray absorption around periastron in order for the microquasar scenario to be consistent with the observed orbital modulation of the TeV gamma-ray flux.
LS 5039是一个TeV伽玛射线双星，具有扩展的射电发射。它由一个紧凑的天体组成，在一个小偏心(e=0.35)的轨道上，围绕一个大质量的O型恒星运行3.9天。致密物体的性质尚未确定。本文假设致密天体为黑洞，通过三维光滑粒子流体力学(SPH)模拟，研究了黑洞对o星风的吸积过程。为了大致模拟恒星辐射有效抵消恒星引力的效果，我们假设O星的引力不作用于风。为了模拟比终端速度慢得多的风，优化模拟的分辨率和计算效率，将风粒子以观测终端速度的一半在狭窄的方面角和垂直角范围内射向黑洞。我们发现质量吸积速率与经典的邦迪-霍伊尔-利特尔顿吸积速率非常接近，约为10^{16}g/s。这个水平的吸积速率将提供足够的能量来产生HESS探测到的伽马射线。由于吸积峰发生在近星体通道附近，我们需要在近星体周围有很强的伽玛射线吸收，以便微类星体情景与观测到的TeV伽玛射线通量的轨道调制一致。
{"title":"The accretion regime of LS 5039: 3-D SPH simulations","authors":"A. Okazaki, G. Romero, S. Owocki","doi":"10.22323/1.067.0074","DOIUrl":"https://doi.org/10.22323/1.067.0074","url":null,"abstract":"LS 5039 is a TeV gamma-ray binary with extended radio emission. It consists of a compact object in the mildly eccentric (e=0.35), 3.9-day orbit around a massive O star. The nature of the compact object is not yet established. In this paper, assuming that the compact object is a black hole, we study the accretion of O-star wind by the black hole, by performing three-dimensional Smoothed Particle Hydrodynamics (SPH) simulations. In order to roughly emulate the effect of the stellar radiation effectively canceling the stellar gravity, we assume that the O star's gravity does not exert on the wind. The wind particles are ejected with half the observed terminal velocity in a narrow range of azimuthal and vertical angles toward the black hole, in order to emulate the wind significantly slower than the terminal speed, and optimize the resolution and computational efficiency of simulations. We find that the mass-accretion rate closely follows the classical Bondi-Hoyle-Littleton accretion rate, which is of the order of 10^{16}g/s around periastron. The accretion rate at this level would provide jets enough power to produce the gamma-rays detected by HESS. Since the accretion peak occurs near the periastron passage, we need a strong gamma-ray absorption around periastron in order for the microquasar scenario to be consistent with the observed orbital modulation of the TeV gamma-ray flux.","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86210184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Optical Gravitational Lensing Experiment is long‐term observing project aiming at detection of microlensing events in crowded stellar fields. As a natural by‐product it collects photometric time‐series of millions of variable stars towards the Galactic Centre and in Magellanic Clouds. In November 2008 third phase of the OGLE will conclude its continuous run since 2001. Huge data set gathered with superb quality is one of very few of such kind currently available. Nearly a billion objects towards the Galactic bulge and Magellanic Clouds need to be now investigated and classified into variability classes. Self‐Organizing Map (SOM) is a promising tool for exploring large multi‐dimensional datasets. It is quick and convenient to train in an unsupervised process and as an outcome it produces naturally clustered patterns. Application of SOM to the new OGLE‐III data set will be presented along with the first preliminary results. SOM technique, tested on OGLE data, will be also implemented within Gaia mission...
{"title":"Self‐Organizing Maps in application to the OGLE data and Gaia Science Alerts","authors":"L. Wyrzykowski, V. Belokurov","doi":"10.1063/1.3059046","DOIUrl":"https://doi.org/10.1063/1.3059046","url":null,"abstract":"The Optical Gravitational Lensing Experiment is long‐term observing project aiming at detection of microlensing events in crowded stellar fields. As a natural by‐product it collects photometric time‐series of millions of variable stars towards the Galactic Centre and in Magellanic Clouds. In November 2008 third phase of the OGLE will conclude its continuous run since 2001. Huge data set gathered with superb quality is one of very few of such kind currently available. Nearly a billion objects towards the Galactic bulge and Magellanic Clouds need to be now investigated and classified into variability classes. Self‐Organizing Map (SOM) is a promising tool for exploring large multi‐dimensional datasets. It is quick and convenient to train in an unsupervised process and as an outcome it produces naturally clustered patterns. Application of SOM to the new OGLE‐III data set will be presented along with the first preliminary results. SOM technique, tested on OGLE data, will be also implemented within Gaia mission...","PeriodicalId":8453,"journal":{"name":"arXiv: Astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84064227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：