The Quintuplet cluster is one of the most massive star clusters in the Milky Way, situated very close to the Galactic center. We present a new search for variable stars in the vicinity of the cluster, using the five-year database of the Vista Variables in the Via Lactea (VVV) ESO Public Survey in the near-infrared. A total of 7586 objects were identified in the zone around $2'$ from the cluster center, using 55 $K_S$-band epochs. Thirty-three stars show $K_S$-band variability, 24 of them being previously undiscovered. Most of the variable stars found are slow/semiregular variables, long-period variables of the Mira type, and OH/IR stars. In addition, a good number of our candidates show variations in a rather short timescale. We also propose four Young Stellar Object (YSO) candidates, which could be cluster members.
Via Lactea(VVV)ESO公开调查中的Vista变量包括对银河系凸起和内盘的近红外时间序列调查,覆盖562平方度的天空,总时间跨度超过5年。在本文中,我们提供了一个更新的帐户的调查,特别是在恒星变率研究的背景下,目前的状况。在这个意义上,我们给我们的努力建设的VVV变星目录(VVV-VSC)的第一个描述。
We present high-angular-resolution radio continuum observations of the Quintuplet cluster, one of the most emblematic massive clusters in the Galactic centre. Data were acquired in two epochs and at 6 and 10 GHz with the Karl J. Jansky Very Large Array. With this work, we have quadrupled the number of known radio stars in the cluster. Nineteen of them have spectral indices consistent with thermal emission from ionised stellar winds, five are consistent with colliding wind binaries, two are ambiguous cases, and one was only detected in a single band. Regarding variability, remarkably we find a …
A near-infrared stellar atlas of the Galactic plane from the VVVX survey
Universidad de Antofagasta(安托法加斯塔大学);Millennium Institute of Astrophysics(天体物理学千年研究所);Universidad Andrés Bello(安德烈斯·贝略大学);Max Planck Institute for Astronomy(马克斯·普朗克天文学研究所);Universidade Federal de Santa Catarina(圣卡塔琳娜联邦大学);Vatican Observatory(梵蒂冈天文台);University of Edinburgh(爱丁堡大学);Universidad de Valparaíso(瓦尔帕莱索大学)
The VVV Templates Project. Towards an Automated Classification of VVV Light-Curves. I. Building a database of stellar variability in the near-infrared
上下文维斯塔变星(英语:Vista Variables in the Vía Láctea)是欧洲南方天文台(ESO)于2010年在可见光和红外巡天望远镜(VISTA)上进行的一项观测,观测对象是银河系的核球和邻近的盘面。VVV最终将提供一个深近红外地图集,其中包括五个通带(ZYJHK_S)的光度和位置,以及一个100万至1000万个可变点源的目录-大多数是未知的-需要分类。目的。我们在这项工作中介绍的VVV模板项目的主要目标是开发和测试用于VVV光变曲线自动分类的机器学习算法。由于VVV是第一个大规模的,多历元的调查恒星的变化在近红外,模板光变曲线所需的训练分类算法是不可用的。在该系列的第一篇论文中,我们描述了红外恒星变化的综合数据库的建设。方法.首先,我们在文献和公共数据档案中进行了系统的搜索,第二,我们协调了一个全球性的观测活动,第三,我们利用VVV变率数据库本身(光学)知名的恒星收集高质量的红外线-数百颗变星的曲线。结果我们现在已经收集了大量的(而且还在增加)红外模板光变曲线。该数据库将用作机器学习算法的训练集,该算法将自动对VVV产生的光变曲线进行分类。这一自动分类的结果将在即将发表的系列论文中介绍。
The VISTA Variables in the Via Lactea survey: A first glance on stellar variability
Via Lactea(VVV)中的VISTA变量是ESO对银河系隆起和南部中面邻近区域的公开近红外变化调查。它将在ZYJHKs滤波器中产生一个深度图集,以及一个约10^9个点源的KS波段时间序列数据库,其中预计>约10^6个点源是可变的。VVV的直接科学目标之一是提供主要距离指标的精确光变曲线,如RR Lyrics恒星,并利用这些数据制作调查区域的3D地图,并最终追踪银河系内部的结构。本文以5年巡天的前1.5年为基础,对VVV测光时间序列的基本性质和总体质量进行了初步评价,并利用这些数据估算了变星源所占的比例。
Open clusters are central elements of our understanding of the Galactic disk evolution, as an accurate determination of their parameters leads to an unbiased picture of our Galaxy's structure. Extending the analysis towards fainter magnitudes in cluster sequences has a significant impact on the derived fundamental parameters, such as extinction and total mass. We perform a homogeneous analysis of six open stellar clusters in the Galactic disk using kinematic and photometric information from the Gaia DR2 and VVV surveys: NGC6067, NGC6259, NGC4815, Pismis18, Trumpler23, and Trumpler20. We implem…
Open clusters are key coeval structures that help us understand star formation, stellar evolution and trace the physical properties of our Galaxy. In the past years, the isolation of open clusters from the field has been heavily alleviated by the access to accurate large-scale stellar parallaxes and proper motions along a determined line of sight. Still, there are limitations regarding their completeness since large-scale studies rely on optical wavelengths. Here we extend the open clusters sequences towards fainter magnitudes complementing the Gaia photometric and astrometric information with…
Red dwarf stars, which represent 75% of stars in the Milky Way, can be studied in great detail in the solar neighborhood where the sample is more complete. We intend to better characterize red dwarf candidates selected from the Gaia Catalog of Nearby Stars using optical and near-infrared photometry from the VVVX Survey, DECaPS, Pan-STARRS, and WISE. We performed a cross-matching procedure among the positions of a color-selected sample of M dwarfs in the VVVX Survey and the Gaia EDR3 sub-catalog of nearby stars. We explored their stellar parameters and spectral types using VOSA. Radii were also…
Long-period variable stars (LPVs) are pulsating red giants, primarily in the asymptotic giant branch phase, and they include both Miras and semi-regular variables (SRVs). Their period-age and period-luminosity relations enable us to trace different stellar populations, as they are intrinsically very bright and cover a wide range in distances and ages. The purpose of this study is to establish a census of LPV stars in a region close to the Galactic center, using the six-year database of the Vista Variables in the Vía Láctea (VVV) ESO Public Survey, as well as to describe the methodology that wa…
The VISTA Variables in the Via Lactea (VVV) survey obtained near-infrared photometry toward the Galactic bulge and the southern disc plane for a decade (2010 - 2019). We designed a modified Lomb-Scargle method to search for large-amplitude ($Δ$Ks > 1.5 mag) mid to long-term periodic variables (P > 10 d) in the 2nd version of VVV Infrared Astrometric Catalogue (VIRAC2-$β$). In total, 1520 periodic sources were discovered, including 59 candidate periodic outbursting young stellar objects (YSOs), based on the unique morphology of the phase-folded light curves, proximity to Galactic HII regions an…
We report a search and analysis of obscured cluster candidates in the "VISTA Variables in the Via Lactea eXtended (VVVX)" ESO Public Survey area encompassing the region between 229.4 < l < 295.2 and -4.3 < b < 4.4 of the southern Galactic disk. We discover and propose 88 new clusters. We improve the completeness of the embedded cluster population in this region, adding small size (linear diameters of 0.2-1.4 pc) and relatively far objects (heliocentric distance between 2 and 4 kpc) to existing catalogues. Nine candidates are proposed to be older open cluster candidates. Three of them (VVVX CL2…
Context. The Vista Variables in the Via Lactea (VVV) near-infrared variability survey explores some of the most complex regions of the Milky Way bulge and disk in terms of high extinction and high crowding. Aims. We add a new wavelength dimension to the optical information available at the American Association of Variable Star Observers International Variable Star Index (VSX-AAVSO) catalogue to test the VVV survey near-infrared photometry to better characterise these objects. Methods. We cross-matched the VVV and the VSX-AAVSO catalogues along with Gaia Data Release 2 photometry and parallax. …
M-dwarf stars are the dominant stellar population in the MilkyWay and they are important for a wide variety of astrophysical topics. The Gaia mission has delivered a superb collection of data, nevertheless, ground-based photometric surveys are still needed to study faint objects. Therefore, the present work aims to identify and characterise M-dwarf stars in the direction of the Galactic bulge using photometric data and with the help of Virtual Observatory tools. Using parallax measurements and proper motions from Gaia Data Release 3, in addition to different colour-cuts based on VISTA filters,…
Long-term Stellar Variability in the Galactic Centre Region
我们报告的变星的检测范围内的11.5' x 11.5'的银河系中心(GC),其中包括拱和五重星系团,揭示了VISTA变星通过Lactea(VVV)调查。有353个源显示出KS波段的变化,其中绝大多数(81%)对应于红巨星,大多数处于渐近巨星分支(AGB)阶段。我们分析了52颗红巨星的长期趋势,这些红巨星不能被归类为典型的脉动恒星类别。计算了9个Mira变量的距离和消光,并讨论了所选消光定律对推导出的距离的影响。我们还报告了存在48个新确定的年轻恒星对象(YSO)的候选人在该地区。
The properties of the Milky Way's nuclear stellar disc give crucial information on the epoch of bar formation. Mira variables are promising bright candidates to study the nuclear stellar disc, and through their period-age relation dissect its star formation history. We report on a sample of $1782$ Mira variable candidates across the central $3\times3\,\mathrm{deg}^2$ of the Galaxy using the multi-epoch infrared VISTA Variables in Via Lactea (VVV) survey. We describe the algorithms employed to select candidate variable stars and then model their light curves using periodogram and Gaussian proce…
Identification of unresolved binaries in the VVV b294 tile: A Pro-Am collaboration using the Virtual Observatory
Universidad Complutense de Madrid(马德里康普顿斯大学);Centro de Astrobiología (CSIC-INTA)(天体生物学中心(西班牙国家研究委员会-国家航空航天技术研究所));Asociación Astronómica AstroHenares(AstroHenares天文协会);Agrupación Astronómica de Córdoba(科尔多瓦天文团);Agrupación Astronómica de Sabadell(萨巴德尔天文团)
We have investigated the stellar and interstellar content of the distant star formation region IRAS 17591-2228 (WISE HII region GAL 007.47+0.06). It is associated to a water maser, whose parallax distance is d=20.4^{+2.8} {-2.2} kpc, supported by independent measurements of proper motion and radial velocity. It is projected in the same direction as an extremely red (J-Ks ~ 6 mag) group of stars, and a shell of mid-infrared emission. We qualify the group of stars as a cluster candidate, VVV CL177. Its radius spans between 0.45' and 1' and contains at least two young stellar objects with an extr…
Near-infrared periodicity in the SPICY catalog. True young stellar objects versus contaminants
Pontificia Universidad Católica de Chile(智利天主教 Pontificia 大学);Universidad de Concepción(康塞普西翁大学);European Southern Observatory(欧洲南方天文台);Millennium Nucleus on Young Exoplanets and their Moons (YEMS)(年轻系外行星及其卫星千年核中心 (YEMS));Universidad de Santiago de Chile(智利圣地亚哥大学);Center for Interdisciplinary Research in Astrophysics and Space Exploration (CIRAS)(天体物理学与太空探索跨学科研究中心 (CIRAS))
High proper motion objects towards the inner Milky Way: characterisation of newly identified nearby stars from the VISTA Variables in the Via Lactea Survey
The decade-long Vista Variables in the Via Lactea (VVV) survey has detected numerous highly variable young stellar objects (YSOs). We present a study of 61 highly variable VVV YSOs ($ΔK_s$ = 1-5 mag), combining near infrared spectra from Magellan and VLT with VVV and NEOWISE light curves to investigate physical mechanisms behind eruptive events. Most sources are spectroscopically confirmed as eruptive variables (typically Class I YSOs) but variable extinction is also seen. Among them, magnetically controlled accretion, identified by H{\sc i} recombination emission (usually accompanied by CO em…