On The Period Determination of ASAS Eclipsing Binaries

Variable stars, or particularly eclipsing binaries, are very essential astronomical occurrence. Surveys are the backbone of astronomy, and many discoveries of variable stars are the results of surveys. All-Sky Automated Survey (ASAS) is one of the observing projects whose ultimate goal is photometric monitoring of variable stars. Since its first light in 1997, ASAS has collected 50,099 variable stars, with 11,076 eclipsing binaries among them. In the present work we focus on the period determination of the eclipsing binaries. Since the number of data points in each ASAS eclipsing binary light curve is sparse, period determination of any system is a not straightforward process. For 30 samples of such systems we compare the implementation of Lomb-Scargle algorithm which is an Fast Fourier Transform (FFT) basis and Phase Dispersion Minimization (PDM) method which is non-FFT basis to determine their period. It is demonstrated that PDM gives better performance at handling eclipsing detached (ED) systems whose variability are non-sinusoidal. More over, using semi-automatic recipes, we get better period solution and satisfactorily improve 53% of the selected object's light curves, but failed against another 7% of selected objects. In addition, we also highlight 4 interesting objects for further investigation.Comment: Presented in International Conferences on Mathematics and Natural Science

Tema procrastination pada film animasi 2D “Udah Besok Aja”

One of the social criticisms of the young workforce is regarding the attitude of procrastination. This counterproductive attitude needs to be addressed and requires educational media. The main problem is the need for the right media that can convey the message and entertain the target audience. The aim is to create short 2-dimensional animated films with effective techniques. The result is an animated film product entitled Udah Besok Aja, which is produced using the frame by frame technique. The method use 2d animation process. The film Udah Besok Aja presents a story that shows the cause and effect associated with procrastination. Pre-production includes extracting story ideas, synopsis, character design, visual background, to storyboards. Film production includes the process of making images with rough-pass, clean-line, in between and lipsync. The application uses Adobe Animate. Post-production is done by compositing, rendering and publishing. In conclusion, the creation of a short 2-dimensional animated film with the title Udah Besok Aja succeeded in presenting the main message, namely criticism of the attitude of procrastinating work. The message is conveyed through the storyline, the choice of words in the dialogue, and the expression of the main character.Kritik sosial untuk angkatan kerja muda salah satunya mengenai sikap menunda pekerjaan. Sikap yang kontraproduktif ini perlu dibenahi dan memerlukan media edukasi. Masalah utama yaitu kebutuhan media yang tepat yang dapat menyampaikan pesan serta menghibur target audiens. Tujuan untuk menciptakan film animasi pendek 2 dimensi dengan teknik yang efektif. Metode yang digunakan adalah penciptaan animasi dua dimensi. Hasilnya adalah produk film animasi berjudul Udah Besok Aja yang diproduksi dengan teknik frame by frame. Film Udah Besok Aja menampilkan cerita yang menunjukkan sebab akibat yang berhubungan dengan sikap menunda pekerjaan. Pra-produksi meliputi penggalian ide cerita,sinopsis, desain karakter, visual background, hingga storyboard. Produksi film meliputi proses pembuatan gambar dengan rough-pass, clean-line, in between dan lipsync. Aplikasi menggunakan Adobe Animate. Pasca produksi dilakukan dengan compositing, rendering dan publishing. Kesimpulannya penciptaan film animasi pendek 2 dimensi dengan judul Udah Besok Aja berhasil menampilkan pesan utama yaitu kritik terhadap sikap menunda pekerjaan. Pesan disampaikan melalui jalan cerita, pilihan kata dalam dialog, serta ekspresi tokoh utama

The discovery of hard X-ray emission in the persistent flux of the Rapid Burster

We report the first detection with INTEGRAL of persistent hard X-ray emission (20 to 100 keV) from the Rapid Burster (MXB 1730-335), and describe its full spectrum from 3 to 100 keV. The source was detected on February/March 2003 during one of its recurrent outbursts. The source was clearly detected with a high signal to noise ratio during the single pointings and is well distinguished from the neighboring source GX 354-0. The 3 - 100 keV X-ray spectrum of the persistent emission is well described by a two-component model consisting of a blackbody plus a power-law with photon index ~ 2.4. The estimated luminosity was ~ 8.5x10^{36} erg/s in the 3 - 20 keV energy band and \~ 1.3x10^{36} erg/s in the 20 - 100 keV energy range, for a distance of 8 kpc.Comment: 5 pages, 6 figures, 1 table. Accepted for publication in A&

Developing Information System on Lunar Crescent Observations

We present a progress report on the development of information system of lunar crescent astronomical observations which will be largely accessible for public domain. This consists of calculations of the Moon's ephemeris as well as systematic real-time lunar crescent observations. A well suited small telescope, equipped with a simple digital detector, is connected to a server to provide information on lunar crescent observations. The system has been used and worked well. The only constraint is poor weather condition. Network of small telescopes, installed at various locations in Indonesia, are currently planned to provide plethora of data. In the long term, this will be used to help to determine the astronomical visibility criteria of lunar crescent for Islamic calendar

Clear sky fraction above Indonesia: an analysis for astronomical site selection

We report a study of cloud cover over Indonesia based on meteorological satellite data, spanning over the past 15 years (from 1996 to 2010) in order to be able to select a new astronomical site capable to host a multi-wavelength astronomical observatory. High spatial resolution of meteorological satellite data acquired from {\it Geostationary Meteorological Satellite 5} ({\it GMS 5}), {\it Geostationary Operational Environmental Satellite 9} ({\it GOES 9}), and {\it Multi-functional Transport Satellite-1R} ({\it MTSAT-1R}) are used to derive yearly average clear fractions over the regions of Indonesia. This parameter is determined from temperature measurement of the IR3 channel (water vapor, 6.7 $\mu$m) for high altitude clouds (cirrus) and from the IR1 channel (10.7 $\mu$m) for lower altitude clouds. Accordingly, an algorithm is developed to detect the corresponding clouds. The results of this study are then adopted to select the best possible sites in Indonesia to be analysed further by performing in situ measurements planned for the coming years. The results suggest that regions of East Nusa Tenggara, located in south-eastern part of Indonesia, are the most promising candidates for such an astronomical site. Yearly clear sky fraction of this regions may reach better than 70 per cent with an uncertainty of 10 per cent.Comment: 15 pages, 13 figures, and 4 table

Chandra Observations of the Dwarf Nova WX Hyi in Quiescence

We report Chandra observations of the dwarf nova WX Hyi in quiescence. The X-ray spectrum displays strong and narrow emission lines of N, O, Mg, Ne, Si, S and Fe. The various ionization states implied by the lines suggest that the emission is produced within a flow spanning a wide temperature range, from T ~ 10^6 K to T >~ 10^8 K. Line diagnostics indicate that most of the radiation originates from a very dense region, with n ~ 10^{13}-10^{14} cm^{-3}. The Chandra data allow the first tests of specific models proposed in the literature for the X-ray emission in quiescent dwarf novae. We have computed the spectra for a set of models ranging from hot boundary layers, to hot settling flows solutions, to X-ray emitting coronae. WX Hyi differs from other dwarf novae observed at minimum in having much stronger low temperature lines, which prove difficult to fit with existing models, and possibly a very strong, broad O VII line, perhaps produced in a wind moving at a few x 10^3 km/s. The accretion rate inferred from the X-rays is lower than the value inferred from the UV. The presence of high-velocity mass ejection could account for this discrepancy while at the same time explaining the presence of the broad O VII line. If this interpretation is correct, it would provide the first detection of a wind from a dwarf nova in quiescence.Comment: accepted to ApJ; 19 pages, 3 figures, 1 tabl

Is T Leonis a superoutbursting intermediate polar?

We present an XMM-Newton analysis of the cataclysmic variable T Leo. The X-ray light curve shows sinusoidal variation on a period P_x equal to 0.89^{+0.14}_{-0.10} times the previously spectroscopically determined orbital period. Furthermore, we find a signal in the power spectrum at 414 sec that could be attributed to the spin period of the white dwarf. If true, T Leo would be the first confirmed superoutbursting intermediate polar IP). The spin profile is double-peaked with a peak separation of about 1/3 spin phases. This appears to be a typical feature for IPs with a small magnetic field and fast white dwarf rotation. An alternative explanation is that the 414 sec signal is a Quasi-periodic Oscillation (QPO) that is caused by mass transfer variation from the secondary, a bright region (``blob'') rotating in the disc at a radius of approximately ~9 Rwd or - more likely - a travelling wave close to the inner disc edge of a dwarf nova with a low field white dwarf. The XMM-Newton RGS spectra reveal double peaked emission for the O VIII Ly alpha line. Scenarios in the IP and dwarf nova model are discussed (an emitting ring in the disc, bright X-ray spot on disc edge, or emitting accretion funnels), but the intermediate polar model is favoured. Supported is this idea by the finding that only the red peak appears to be shifted and the `blue' peak is compatible with the rest wavelength. The red peak thus is caused by emission from the northern accretion spot when it faces the observer. Instead, the peak at the rest wavelength is caused when the southern accretion funnel is visible just on the lower edge of the white dwarf - with the velocity of the accreting material being perpendicular to the line of sight.Comment: 11 pages, 15 figures, accepted by A&

Study of the plutino object (208996) 2003 AZ84 from stellar occultations: size, shape and topographic features

We present results derived from four stellar occultations by the plutino object (208996) 2003~AZ$_{84}$, detected at January 8, 2011 (single-chord event), February 3, 2012 (multi-chord), December 2, 2013 (single-chord) and November 15, 2014 (multi-chord). Our observations rule out an oblate spheroid solution for 2003~AZ$_{84}$'s shape. Instead, assuming hydrostatic equilibrium, we find that a Jacobi triaxial solution with semi axes $(470 \pm 20) \times (383 \pm 10) \times (245 \pm 8)$~km % axis ratios $b/a= 0.82 \pm 0.05$ and $c/a= 0.52 \pm 0.02$, can better account for all our occultation observations. Combining these dimensions with the rotation period of the body (6.75~h) and the amplitude of its rotation light curve, we derive a density $\rho=0.87 \pm 0.01$~g~cm$^{-3}$ a geometric albedo $p_V= 0.097 \pm 0.009$. A grazing chord observed during the 2014 occultation reveals a topographic feature along 2003~AZ$_{84}$'s limb, that can be interpreted as an abrupt chasm of width $\sim 23$~km and depth $> 8$~km or a smooth depression of width $\sim 80$~km and depth $\sim 13$~km (or an intermediate feature between those two extremes)

Analisis dan Optimalisasi Sistem Antrian di PT Bank Rakyat Indonesia (BRI) KCP Pejuang

Bank BRI KCP Pejuang mempunyai rata-rata waktu menunggu yaitu 14,89 menit melebihi standar waktu pelayanan teller perusahaan sebesar 5 menit. Rata-rata waktu menunggu ini lebih lambat 2,97 kali lipat dibandingkan dengan waktu standar perusahaan. Perlu dilakukan penelitian yang bertujuan untuk menentukan nilai performansi sistem antrian pada bank BRI KCP Pejuang dan menentukan jumlah teller yang dapat memperkecil waktu tunggu nasabah. Metode yang digunakan adalah sistem antrian Multi channel-single phase (M/M/C). Hasil penelitian menunjukkan bank BRI KCP Pejuang mempunyai nilai performansi sistem antrian yaitu tingkat kegunaan fasilitas (P) sebesar 87%, probabilitas tidak adanya pelanggan (P0) 3,3%, rata-rata jumlah pelanggan dalam antrian (Lq) sebesar 5,250 orang, rata-rata jumlah pelangan dalam sistem (Ls) sebesar 7,866 orang, rata-rata waktu menunggu dalam antrian (Wq) sebesar 11,244 menit, rata-rata menunggu dalam sistem (Ws) sebesar 16,308 menit, dan probabilitas nasabah yang telah memasuki sistem dan harus menunggu untuk dilayani (Pw) sebesar 75%. Jumlah teller yang lebih baik untuk memperkecil waktu tunggu nasabah adalah 4 karena dapat menurunkan rata-rata panjang antrian dalam sistem (Ls) sebesar 58%, waktu menunggu nasabah dalam sistem (Ws) sebesar 58% yaitu dari 16,308 menit menjadi 7,044 menit, dan probabilitas seorang nasabah yang telah memasuki sistem dan harus menunggu untuk dilayani (Pw) sebesar 49%

Penerapan Multiple Regression Model dengan Dummy Variables dalam Prediksi Bantuan Logistik atas Dampak Bencana Awan Panas Gunung Merapi

Indonesia merupakan salah satu negara yang berada di kawasan cincin api (ring of fire), dimana memiliki risiko terjadinya bencana yang sangat tinggi. Salah satu bencana alam yang sering terjadi di Indonesia adalah peristiwa erupsi gunung api. Jumlah gunung api aktif di Indonesia hingga saat ini adalah 69 gunung, salah satunya Gunung Merapi. Selama tahun 2021, status Gunung Merapi dilansir oleh Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi adalah Siaga dengan potensi terjadinya erupsi masih sangat tinggi. Salah satu ancaman yang dihasilkan dari erupsi Gunung Merapi adalah bahaya awan panas. Riset ini bertujuan untuk membuat dan mengembangkan model prediksi bencana erupsi Gunung Merapi dengan menerapkan model regresi dengan variabel dummy, didasarkan pada faktor-faktor yang mempengaruhi awan panas sehingga dapat diketahui prediksi jarak luncuran awan panas. Faktor-faktor yang mempengaruhi jarak jangkauan awan panas meliputi kecepatan angin, volume awan panas, frekuensi terjadinya gempa guguran, dan arah hembusan angin. Riset ini juga bertujuan untuk membuat prediksi jumlah korban jiwa akibat letusan Gunung Merapi melalui beberapa pengembangan skenario analisis sensitivitas luncuran awan panas serta memprediksikan jumlah barang bantuan yang diperlukan oleh para pengungsi disesuaikan dengan demografi penduduk wilayah terdampak didasarkan atas persamaan regresi yang telah dibuat. Jumlah pengungsi didominasi dari Kabupaten Sleman (48.759 orang), dan diikuti oleh Kabupaten Magelang (35.824 orang), dan Kabupaten Klaten (13.942 orang). Di sisi lain, jumlah minimum standar pemenuhan kebutuhan barang bantuan telah disesuaikan Peraturan Kepala BNPB No. 7 Tahun 2008 dan rencana kontingensi setiap kabupaten yang terdampak