Determination of mass of IGR J17091-3624 from "Spectro-Temporal" variations during onset-phase of the 2011 outburst

The 2011 outburst of the black hole candidate IGR J17091-3624 followed the canonical track of state transitions along with the evolution of Quasi-Periodic Oscillation (QPO) frequencies before it began exhibiting various variability classes similar to GRS 1915+105. We use this canonical evolution of spectral and temporal properties to determine the mass of IGR J17091-3624, using three different methods, viz : Photon Index ($\Gamma$) - QPO frequency ($\nu$) correlation, QPO frequency ($\nu$) - Time (day) evolution and broadband spectral modelling based on Two Component Advective Flow. We provide a combined mass estimate for the source using a Naive Bayes based joint likelihood approach. This gives a probable mass range of 11.8 M$_{\odot}$ - 13.7 M$_{\odot}$. Considering each individual estimate and taking the lowermost and uppermost bounds among all three methods, we get a mass range of 8.7 M$_{\odot}$ - 15.6 M$_{\odot}$ with 90% confidence. We discuss the probable implications of our findings in the context of two component accretion flow.Comment: 10 pages, 5 figures (4 in colour), 2 tables. Accepted for publication in Ap

Accretion disk around the rotating Damour-Solodukhin wormhole

A new rotating generalization of the Damour-Solodukhin wormhole (RDSWH), called Kerr-like wormhole, has recently been proposed and investigated by Bueno \textit{et al} for echoes in the gravitational wave signal. We show a novel feature of the RDSWH, viz., that the kinematic properties such as the ISCO\ or marginally stable radius $r_{\text{ms}}$, efficiency $\epsilon$ and the disk potential $V_{\text{eff}}$ are \textit{independent} of $\lambda$ (which means they are identical to their KBH counterparts for any given spin). Differences however appear in the emissivity properties for higher values $0.1<\lambda\leq 1$ (say) and for the extreme spin $a_{\star}=0.998$. The kinematic and emissivity are generic properties as variations of the wormhole mass and the rate of accretion within the model preserve these properties. Specifically, the behavior of the luminosity peak is quite opposite to each other for the two objects, which could be useful from the viewpoint of observations. Apart from this, an estimate of the difference $\Delta_{\lambda}$ in the maxima of flux of radiation $F(r)$ shows non-zero values but is too tiny to be observable at present for $\lambda < 10^{-3}$ permitted by the strong lensing bound. The broad conclusion is that RDSWH\ are experimentally indistinguishable from KBH by accretion characteristics.Comment: 9 pages, 3 tables, 13 figure

Noise In Nonohmic Regimes Of Disordered Systems

We present here a short review of mainly experimental properties of noise as disordered systems are driven into non-ohmic regimes by applying voltages of few volts only. It is found that the noise does not simply follow the resistance in that the direction of change of noise could be opposite to that of resistance. It is discussed how this and other properties make the noise a complementary and incisive tool for studying complex systems, particularly its dynamic properties. Study of noise in non-ohmic regimes in physical systems is rather in a nascent stage. Some of the open issues are highlighted.Comment: 9 Pages, 7 figures. Reported in Unsolved Problems of Noise and Fluctuations: UPoN 2005, Gallipoli, Italy, June 6-10, 200

Landscape Planning And Management Of Minangkabau Land (Perencanaan dan Pengelolaan Lanskap Minangkabau)

Dalam Suku Minangkabau, lahan dikelola secara komunal. Unit pengelolaan dilakukan melalui sistem nagari, dimana didalamnya diatur pola penggunaan lahan dan sistem waris. Perkembangan dalam pola penggunaan lahan, baik disebabkan oleh pertambahan populasi penduduk maupun Perubahan orientasi penggunaan lahan menjadi lebih berorientasi ekonomi dapat menjadi penyebab hilangnya sistem adat dalam manyarakat Minangkabau ini. Sebagai upaya untuk mempertahankan nilai-nilai adat serta sebagai upaya pemanfaatan lahan yang sesuai dengan kharakteristik lingkungan setempat maka dipelukan panduan pengelolaan lansekapnya

Ungkapan Kata Hanasu, Iu, Dan Shaberu Dalam Bahasa Jepang

Di dalam bahasa Jepang banyak sekali terdapat ungkapan (hyougen) kata-kata yang bersinonim (ruigigo). Walaupun ungkapan kata-kata yang bersinonim tersebut mempunyai makna yang sama atau hampir sama, tetapi dalam pengungkapannya terdapat perbedaan. Perbedaan ini disebabkan beberapa faktor, seperti faktor waktu, tempat, sosial, kegiatan, dan nuansa makna. Kesalahan dalam pemakaian ungkapan yang bersinonim tersebut sering menimbulkan kesalahan pahaman dalam komunikasi bahkan akan menimbulkan kebingungan lawan bicara. Diantara ungkapan kata yang merupakan sinonim tersebut adalah kata hanasu, iu, dan shaberu yang mempunyai makna sama, yaitu berkata, berbicara

Lensing observables: Massless dyonic vis-\`a-vis Ellis wormhole

Stable massless wormholes are theoretically interesting in their own right as well as for astrophysical applications, especially as galactic halo objects. Therefore, the study of gravitational lensing observables for such objects is of importance, and we do here by applying the parametric post-Newtonian method of Keeton and Petters to massless dyonic charged wormholes of the Einstein-Maxwell-Dilaton field theory and to the massless Ellis wormhole of the Einstein minimally coupled scalar field theory. The paper exemplifies how the lensing signatures of two different solutions belonging to two different theories could be qualitatively similar from the observational point of view. Quantitative differences appear depending on the parameter values. Surprisingly, there appears an unexpected divergence in the correction to differential time delay, which seems to call for a review of its original derivation.Comment: 16 pages, 7 figure