New Non-Parametric Approach to Determine Proper Motion of Star Clusters

The bulk motion of star clusters can be determined after careful membership analysis using parametric or non-parametric approaches. This study aims to implement non-parametric membership analysis based on Binned Kernel Density Estimator which accounts measurements errors (simply called BKDE-e) and to determine the average proper motion of each cluster. This method is applied to 178 selected star clusters with angular diameter less than 20 arc minutes. Proper motion data from UCAC4 are used for membership determination. Non-parametric analysis using BKDE-e successfully determined the average proper motion of 129 clusters, with good accuracy. Compared to COCD and NCOVOCC, there are 79 clusters with less than $3\sigma$ difference. Moreover, we are able to analyse distribution of the member stars in vector point diagram which is not always normal distribution.Comment: 2 pages, 5 figures, APRIM 201

Open Cluster Evolutions in Binary System: How They Dissolved

Binarity among stellar clusters in galaxy is such a reality which has been realized for a long time, but still hides several questions and problems to be solved. Some of binary star clusters are formed by close encounter, but the others are formed together from similar womb. Some of them undergo separation process, while the others are in the middle of merger toward common future. The products of merger binary star cluster have typical characteristics which differ from solo clusters, especially in their spatial distribution and their stellar members kinematics. On the other hand, these merger products still have to face dissolving processes triggered by both internal and external factors. In this study, we performed N-body simulations of merger binary clusters with different initial conditions. After merging, these clusters dissolve with greater mass-loss rate because of their angular momentum. These rotating clusters also experience more deceleration caused by external tidal field.Comment: presented in International Conference on Mathematics and Natural Sciences 201

Efek Hepatoprotektor Ekstrak Tempe Kedelai pada Mencit (Mus musculus) yang Diinduksi Parasetamol

Background: Soybean tempeh is known to contain various kinds of antioxidants such as vitamin C, vitamin E, vitamin B2, saponins, isoflavones, phytic acid, lecithin, iron, and phytosterol. Antioxidants are thought to be hepatoprotective. The objective of this research is to know the influence of soybean tempeh extract to the liver histological damage of mice (Mus musculus) and the increase of soybean tempeh extract dose can also increase protection effect to the liver histological damage of mice (Mus musculus) which is induced by paracetamol. Methods: This was laboratory experimental research with the post test only controlled group design. Samples were 32 male mice, Swiss webster type, 2-3 months old age and ± 20 g of each weight. Samples were divided into 4 groups of 8 mice each. Sampling technique used in this research was incidental sampling. Mice for control group (K) and P1 group will be given aquadest for 14 days in a row. The P2 and P3 group will be given soybean tempeh extracts dose for 14 days in a row. Soybean tempeh extracts dose in each group was 2.2 mg/20 g weight of mice and 4.4 mg/20 g weight of mice. Paracetamol will be given to P1, P2, and P3, with dose 5 mg/20g weight of mice on the 12 th to 14 th days. On the 15 th day, hepar of mice was taken and stainned with Hematoxylin Eosin (HE) for histopathological study. The hepar cells of mice were observed microscopically by counting the number of necrosis cells on the centrolobuler zone. The data were analyzed by Oneway ANOVA test and Post Hoc test (α=0.05). Results:The average damage of hepar cells in the K, P1, P2, P3 were 20.75 ± 1.58; 85.00 ± 2.98; 43.75 ± 2.92; 31.00±2.00consecutively. The results of Oneway ANOVA test showed a significant difference in all group (p < 0.05). The results of Post Hoc test showed significant differences between K – P1, K – P2, K – P3, P1 – P2, P1 – P3, and P2 – P3 with p < 0.05. Conclusion: The soybean tempeh extracts can prevent the histological damage of the hepar cells of mice (Mus musculus) and the increase of soybean tempeh extracts dose followed by the increase of protection effect to the liver cell damaging of mice which is induced by paracetamo

Kajian Batimetri Bagi Kepentingan Penambahan Kedalaman Kolam Pelabuhan Di Perairan Tegal

Perairan Tegal merupakan wilayah pesisir bagian utara dari Kota Tegal, Jawa Tengah yang dimanfaatkan sebagai area pelabuhan. Pelabuhan Tegal merupakan pelabuhan nasional yang mempunyai kegiatan utama yaitu perbaikan kapal atau docking untuk kapal berukuran kecil sampai sedang. Kegiatan lain yang dilakukan oleh Pelabuhan Tegal yaitu aktivitas bongkar muat, namun hanya dapat dilakukan oleh kapal yang mempunyai draft kapal maksimal 3 meter karena perairan yang dangkal. Menanggapi hal tersebut, pemerintah Kota Tegal berupaya untuk melakukan pengembangan pelabuhan supaya pelabuhan yang baru dapat melakukan kegiatan docking dan bongkar muat dengan maksimal. Tujuan penelitian ini adalah mendapatkan informasi tentang karakteristik pasang surut dan kondisi batimetri yang disajikan dalam bentuk peta serta menentukan kedalaman tambahan supaya kapal kapasitas 5000 DWT dapat masuk ke dalam kolam pelabuhan. Metode yang digunakan yaitu metode kualitatif yaitu metode yang digunakan untuk mendapatkan data yang mendalam, suatu data yang mengandung makna. Data pasut diolah menggunakan metode admiralty dan kedalaman perairan dihitung dari muka surutan (LLWL) dengan menggunakan Singlebeam Echosounder. Hasil penelitian menunjukan perairan Tegal mempunyai tipe pasang surut campuran dominan ganda dengan muka air rata – rata (MSL) 152,6 cm dan muka surutan sekaligus air rendah terendah (LLWL) 100,71 cm. kedalaman perairan berkisar antara 0,7 – 3 meter dan disarankan untuk menambah kedalaman 6,8 – 8,8 meter

Dynamics of the Disks of Nearby Galaxies

I describe how the dynamics of galactic disks can be inferred by imaging and spectroscopy. Next I demonstrate that the decomposition of the rotation curves of spiral galaxies into the contributions by the various components of the galaxies is highly degenerate. Constraints on the decomposition can be found by considering implications for the dynamics of the galactic disks. An important diagnostic is the Toomre Q stability parameter which controls the stability of a galactic disk against local Jeans collapse. I also show how the density wave theory of galactic spiral arms can be employed to constrain the mass of a galactic disk. Applying both diagnostics to the example of NGC 2985 and discussing also the implied mass-to-light ratio I demonstrate that the inner parts of the galaxy, where the optical disk resides, are dominated by baryons. When I apply this method to the disks of low surface brightness galaxies, I find unexpectedly high mass-to light ratios. These could be explained by population synthesis models which assume a bottom heavy initial mass function similar to the recently proposed `integrated galactic initial mass function'.Comment: 6 pages, 12 figures, invited contribution to `Galactic and Stellar Dynamics in the era of high resolution surveys', Strasbourg, March 16 -20, 200

CADIS has seen the Virgo overdensity and parts of the Monoceros and `Orphan' streams in retrospect

We reanalyze deep star counts in five CADIS fields. The data are presented as vertical density distributions of stars perpendicular to the Galactic plane. In three fields the profiles are consistent with each other, while in two fields significant overdensities of stars are found. The overdensity in one field can be associated with the Virgo overdensity which can be traced right into the disk of the Milky Way. Using this detection we estimate the mass of the Virgo overdensity and show that this is equivalent to the stellar content of a Local Group dwarf spheroidal galaxy. The overdensity in the second field is more difficult to associate with a previously known overdensity. We suggest that it is related both to the Monoceros stream and the recently discovered Orphan stream.Comment: 4 pages, 3 figures, accepted as Research Note by Astron. Astrophy

On the age heterogeneity of the Pleiades, Hyades and Sirius moving groups

We investigate the nature of the classical low-velocity structures in the local velocity field, i.e. the Pleiades, Hyades and Sirius moving groups. After using a wavelet transform to locate them in velocity space, we study their relation with the open clusters kinematically associated with them. By directly comparing the location of moving group stars in parallax space to the isochrones of the embedded clusters, we check whether, within the observational errors on the parallax, all moving group stars could originate from the on-going evaporation of the associated cluster. We conclude that, in each moving group, the fraction of stars making up the velocity-space overdensity superimposed on the background is higher than the fraction of stars compatible with the isochrone of the associated cluster. These observations thus favour a dynamical (resonant) origin for the Pleiades, Hyades and Sirius moving groups.Comment: 8 pages, 8 figures, accepted for publication in A&

Kinematics of Nearby Subdwarf Stars

We present an analysis of the space motions of 742 subdwarf stars based on the sample of Carney et al. (1994, CLLA). Hipparcos parallaxes, TYC2+HIP proper motions and Tycho2 proper motions were combined with radial velocities and metallicities from CLLA. The kinematical behavior is discussed in particular in relation to their metallicities. The majority of these sample stars have metal abundances of [Fe/H] >-1 and represent the thick disk population. The halo component, with [Fe/H] <-1.6, is characterized by a low mean rotation velocity and a radially elongated velocity ellipsoid. In the intermediate metallicity range (-1.6 < [Fe/H] <-1), we find a significant number of subdwarfs with disklike kinematics. We interpret this population of stars as a metal-weak thick disk population.Comment: 6 pages, 7 figures, accepted by Astronomy & Astrophysic

Chemical compositions of stars in two stellar streams from the Galactic thick disk

We present abundances for 20 elements for stars in two stellar streams identified by Arifyanto & Fuchs (2006, A&A, 449, 533): 18 stars from the Arcturus stream and 26 from a new stream, which we call AF06 stream, both from the Galactic thick disk. Results show both streams are metal-poor and very old (10$-$14 Gyrs) with kinematics and abundances overlapping with the properties of local field thick disk stars. Both streams exhibit a range in metallicity but with relative elemental abundances that are identical to those of thick disk stars of the same metallicity. These results show that neither stream can result from dissolution of an open cluster. It is highly unlikely that either stream represents tidal debris from an accreted satellite galaxy. Both streams most probably owe their origin to dynamical perturbations within the Galaxy.Comment: 10 figures, Accepted for publication in MNRA