搜索到4159篇“ NGC“的相关文章
星暴矮星系NGC 5253周围的中性氢气体分布
2024年
中性氢(HI)气体是恒星形成的基本物质,驱动着星系的演化。对于星暴矮星系NGC 5253,过去的研究利用射电干涉阵观测到的HI气体呈不对称分布,向东北方向延伸约7 kpc。这一延展结构可能表明NGC 5253与其附近的旋涡星系M 83之间存在动力学联系。为研究这两个星系之间可能存在的HI气体连接,从绿岸望远镜获得了射电L波段对NGC 5253周围的HI成图数据,探测到NGC 5253和M 83之间可能存在的7个HI气体云团。这些HI气体云团候选体主要分布在东北方向,由NGC 5253延展至距离超过60 kpc外。这些气体云团可能在触发矮星系NGC 5253剧烈的恒星形成活动中发挥重要作用。
沃佳怡蔡肇伟左沛陈天禄
关键词:恒星形成
New HⅠObservations Toward the NGC 5055 Galaxy Group with FAST
2024年
We report a new high-sensitivity HⅠmapping observation of the NGC 5055 galaxy group over an area of 1°.5×0°.75 with the Five-hundred-meter Aperture Spherical radio Telescope(FAST).Our observation reveals that the warped HⅠdisk of NGC 5055 is more extended than what was previously observed by WSRT,out to239(61.7 kpc).The total HⅠmass of NGC 5055 is determined to be~1.1×10^(10)M_Θ.We identified three HⅠclouds with HⅠmasses of the order of~10^(7)M_Θat the southeastern edge of the HⅠdisk,as well as a candidate high-velocity cloud with an HⅠmass of(1.2±0.5)×10^(6)M_Θto the north of NGC 5055.The HⅠcontent of UGCA337 is robustly detected for the first time by the FAST observations.It has a narrow HⅠlinewidth of W_(50)=17.4±3.8 km s^(-1)with a total HⅠmass of(3.5±0.3)×10^(6)M_Θ.Comparing the gas content and g-r color of UGCA 337 with typical low-mass dwarf galaxies,UGCA 337 appears relatively gas-poor despite its blue color.This suggests that UGCA 337 may have undergone gas stripping in the past.We also analyzed the possible origin of the diffuse HⅠclouds located at the outskirts of NGC 5055,and speculate that they might be the remnant features of a merger event in the past.
Xiao-Lan LiuMing ZhuJin-Long XuPeng JiangChuan-Peng ZhangNai-Ping YuJun-Jie WangYan-Bin Yang
关键词:GALAXIES
A Possible γ-Ray Pulsation from PSR J1740-5340B in the Globular Cluster NGC 6397
2024年
Recently, a new radio millisecond pulsar(MSP) J1740-5340B, hosted in the globular cluster(GC) NGC 6397,was reported with a 5.78 ms spin period in an eclipsing binary system with a 1.97 days orbital period. Based on a modified radio ephemeris updated by tool tempo2, we analyze the ~15 yr γ-ray data obtained from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope and detect PSR J1740-5340B's γ-ray pulsation at a confidence level of ~4σ with a weighted H-test value of ~26. By performing a phase-resolved analysis, the γ-ray luminosity in on-pulse interval of PSR J1740-5340B is L_(γ)~ 3.8 × 10^(33) erg s^(-1) using NGC 6397's distance of 2.48 kpc. And γ-rays from the on-pulse part of PSR J1740-5340B contribute ~90% of the total observed γ-ray emissions from NGC 6397. No significant γ-ray pulsation of another MSP J1740-5340A in the GC is detected.Considering that the previous four cases of MSPs in GCs, more data in γ-ray, X-ray, and radio are encouraged to finally confirm the γ-ray emissions from MSP J1740-5340B, especially starving for a precise ephemeris.
Jiao ZhengPengfei ZhangLi Zhang
PDA及其衍生NGC膜包覆A-TiO_(2)可见光催化氧化乙醛
2024年
针对TiO_(2)在可见光波段对连续流动态乙醛的催化降解性能弱等问题,采用贻贝仿生化学策略及高温炭化工艺构建了广谱性聚多巴胺(PDA)及其衍生N掺杂炭(NGC)膜包覆的核壳型锐钛矿TiO_(2)(AT)(AT@P和AT@C)。利用扫描电镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见光漫反射光谱(UV-vis DRS)、瞬时光电流密度-时间曲线(I-t)和交流阻抗(EIS)等手段对材料的物化性质及光电学性质进行表征,研究复合AT中不同PDA包覆量及最佳包覆量时炭化前、后微观成分和结构变化对乙醛的可见光催化性能的影响。结果表明:PDA的包覆显著增强了AT的可见光吸收能力和光生载流子分离能力,极大地提高了其在可见光照下光催化降解乙醛的活性。当多巴胺添加量为50 mg时获得的AT@P-50相比AT@P-10和AT@P-100展现出较高的降解效率(71%),是AT的2.09倍。π共轭结构高活性N(石墨化N)的转化可进一步提高材料的载流子分离效率和界面迁移率,促进AT的光催化活性及稳定性的提升。最佳PDA包覆量时炭化衍生NGC包覆的AT@C-50的乙醛可见光降解效率高达77%,分别是AT和AT@P-50的2.26、1.08倍。在相同的连续流动体系和乙醛浓度条件下,合成的AT@P-x(x=10、50和100)、AT@C-50相比其他精心设计的TiO_(2)复合材料对乙醛具有更为优异的可见光催化降解性能。此外,采用原位红外漫反射技术(in-situ DRIFTS)探究AT@C-50在乙醛催化过程中间产物的演变行为,并揭示了可能的催化路径和反应机制。
黄一维朱梅萍
Observation of HⅠaround three Satellite Galaxies of M31 with FAST:AndromedaⅡ,NGC 205,and NGC 185
2024年
With the exceptional sensitivity of the Five-hundred-meter Aperture Spherical radio Telescope,we conducted observations of the neutral hydrogen(HⅠ)in the circumgalactic medium of Andromeda’s(M31)satellite galaxies,specifically AndromedaⅡ,NGC 205,and NGC 185.Initially,three drift scans were executed for these satellites,with a detection limit of 4×10^(18)cm^(-2)(approximately 1.88×10^(3)M_Θof HⅠmass),followed by a more in-depth scan of a specific region.We discovered a C-shaped HⅠarc structure sharing a position and line-of-sight velocity similar to a stellar ring structure around AndromedaⅡ,hinting at a potential connection with AndromedaⅡ.In the context of NGC 205,we identified two mass concentrations in the northeast direction,which could be indicative of tidal streams resulting from the interaction between this galaxy and M31.These new lumps discovered could be very helpful in solving the missing interstellar medium problem for NGC 205.Observations regarding NGC 185are consistent with previous studies,and we did not detect any additional HⅠmaterial around this galaxy.These observational results enhance our understanding of the evolution of these satellite galaxies and provide insight into their historical interactions with the galaxy M31.
Ziming LiuJie WangYingjie JingChen XuTiantian LiangQingze ChenZerui LiuZhipeng HouYougang Wang
关键词:ISMGALAXIES
Isochrone Fitting of Galactic Globular Clusters—Ⅵ.High-latitude Clusters NGC 5024 (M53),NGC 5053,NGC 5272 (M3),NGC 5466,and NGC7099 (M30)
2024年
We fit various color–magnitude diagrams(CMDs) of the high-latitude Galactic globular clusters NGC 5024(M53),NGC 5053,NGC 5272(M3),NGC 5466,and NGC 7099(M30) by isochrones from the Dartmouth Stellar Evolution Database and Bag of Stellar Tracks and Isochrones for α–enrichment [α/Fe] = +0.4.For the CMDs,we use data sets from Hubble Space Telescope,Gaia,and other sources utilizing,at least,25 photometric filters for each cluster.We obtain the following characteristics with their statistical uncertainties for NGC 5024,NGC 5053,NGC 5272,NGC 5466,and NGC 7099,respectively:metallicities [Fe/H] =-1.93 ± 0.02,-2.08 ± 0.03,-1.60 ± 0.02,-1.95 ± 0.02,and-2.07 ± 0.04 dex with their systematic uncertainty 0.1 dex;ages 13.00 ± 0.11,12.70 ± 0.11,11.63 ± 0.07,12.15 ± 0.11,and 12.80 ± 0.17 Gyr with their systematic uncertainty 0.8 Gyr;distances(systematic uncertainty added) 18.22 ± 0.06 ± 0.60,16.99 ± 0.06 ± 0.56,10.08 ± 0.04 ± 0.33,15.59 ±0.03 ± 0.51,and 8.29 ± 0.03 ± 0.27 kpc;reddenings E(B-V) = 0.023 ± 0.004,0.017 ± 0.004,0.023 ± 0.004,0.023 ± 0.003,and 0.045 ± 0.002 mag with their systematic uncertainty 0.01 mag;extinctions AV= 0.08 ± 0.01,0.06 ± 0.01,0.08 ± 0.01,0.08 ± 0.01,and 0.16 ± 0.01 mag with their systematic uncertainty 0.03 mag,which suggest the total Galactic extinction AV= 0.08 across the whole Galactic dust to extragalactic objects at the North Galactic Pole.The horizontal branch morphology difference of these clusters is explained by their different metallicity,age,mass-loss efficiency,and loss of low-mass members in the evolution of the core-collapse cluster NGC 7099 and loose clusters NGC 5053 and NGC 5466.
G.A.GontcharovS.S.SavchenkoA.A.MarchukC.J.BonattoO.S.RyutinaM.Yu.KhovritchevV.B.Il'inA.V.MosenkovD.M.PoliakovA.A.Smirnov
牙胶(RY-NGC
1.本外观设计产品的名称:牙胶(RY‑NGC)。;2.本外观设计产品的用途:用于婴儿磨牙的牙胶。;3.本外观设计产品的设计要点:在于形状。;4.最能表明设计要点的图片或照片:立体图。
邱隆海
星暴星系NGC 253
2024年
光阴,当日影在日暑上一寸寸移动时,其实是我们的地球和太阳在一刻不停地发生着相对运动。与此同时,太阳系也在银河系中不断运动。当我们按下时间的加速键,将更直观地发现我们的宇宙并非静态,每一刻它都在成长和演进——天体之间在进行着相互作用,新的天体在不断诞生,年老的天体也渐渐归于冷寂。
星将
关键词:银河系天体星暴星系太阳系宇宙
Variable Stars in the 50BiN Open Cluster Survey.Ⅲ.NGC 884
2024年
Open clusters are the basic building blocks that serve as a laboratory for the study of young stellar populations in the Milky Way.Variable stars in open clusters provide a unique way to accurately probe the internal structure,temporal and dynamical evolutionary stages of individual stars and the host cluster.The most powerful tool for such studies is time-domain photometric observations.This paper follows the route of our previous work,concentrating on a photometric search for variable stars in NGC 884.The target cluster is the companion of NGC869,forming the well-known double cluster system that is gravitationally bound.From the observation run in 2016 November,a total of 9247 B-band CCD images and 8218Ⅴ-band CCD images were obtained.We detected a total of 15 stars with variability in visual brightness,including five Be stars,three eclipsing binaries,and seven of unknown types.Two new variable stars were discovered in this work.We also compared the variable star content of NGC 884 with its companion NGC 869.
Lin-Hong WangQian-Heng NieKun WangXiao-Dian ChenChun-Guang ZhangLi-Cai DengXiao-Bin ZhangTian-Lu Chen
关键词:STARSGENERAL
LED高顶灯(NGC9834)
1.本外观设计产品的名称:LED高顶灯(NGC9834)。;2.本外观设计产品的用途:用于车间厂房、物流仓库、工程机械、粮油、酒制品等同等高度厂房的照明使用。;3.本外观设计产品的设计要点:在于形状。;4.最能表明设计要...
徐素王祖福

相关作者

高新华
作品数:11被引量:10H指数:2
供职机构:常州大学
研究主题:疏散星团 视向速度 NGC 星等 球状星团
陈力
作品数:39被引量:61H指数:4
供职机构:中国科学院上海天文台
研究主题:疏散星团 天体测量 银河系 球状星团 恒星
黄红
作品数:5被引量:3H指数:1
供职机构:华中师范大学物理科学与技术学院粒子物理研究所
研究主题:乳胶室 高能 测定仪 NGC 核乳胶
蔡勖
作品数:104被引量:75H指数:5
供职机构:华中师范大学
研究主题:高能重离子碰撞 复杂网络 ALICE实验 碰撞 夸克-胶子等离子体
裘予雷
作品数:29被引量:77H指数:4
供职机构:中国科学院国家天文台
研究主题:超新星 图像 望远镜 天文台 巡天