Use of geometric Brownian motion to forecast stock market scenario using post covid-19 NEPSE index

Stock market is one of the fields where the randomness is prominent factor to be considered. Although many stochastic process deals which the randomness found in nature through the interdisciplinary subject like Econophysics, many of them exhibits cumbersome trends. So, Geometric Brownian motion (GBM) is used to analyze the market scenario of Nepal on the basis of the parameter; NEPSE Index along with the prediction of indices through python programming platform. Python simulation was carried out to check the consistency by implying it to the stable market timeline 2003/2004. And after the verification of the model proposed in the stable market year, the model (GBM) is employed to the unstable timeline; pandemic situation by COVID-19 in 2020. Mapping of Nepal stock market through GBM was found to be consistent with the standard forecasting accuracy making GBM one of the flexible and consistent to predict stock market scenario of Nepal accounting the random nature. BIBECHANA 18 (2) (2021) 50-6

Use of geometric Brownian motion to forecast stock market scenario using post covid-19 NEPSE index

Stock market is one of the fields where the randomness is prominent factor to be considered. Although many stochastic process deals which the randomness found in nature through the interdisciplinary subject like Econophysics, many of them exhibits cumbersome trends. So, Geometric Brownian motion (GBM) is used to analyze the market scenario of Nepal on the basis of the parameter; NEPSE Index along with the prediction of indices through python programming platform. Python simulation was carried out to check the consistency by implying it to the stable market timeline 2003/2004. And after the verification of the model proposed in the stable market year, the model (GBM) is employed to the unstable timeline; pandemic situation by COVID-19 in 2020. Mapping of Nepal stock market through GBM was found to be consistent with the standard forecasting accuracy making GBM one of the flexible and consistent to predict stock market scenario of Nepal accounting the random nature. BIBECHANA 18 (2) (2021) 50-6

Spatial orientation of galaxies in supercluster S[227+006+0078]

We present a study of spin vector orientation of 1218 SDSS (Sloan Digital Sky Survey) galaxies in Supercluster S [227+006+0078] having redshift 0.07 to 0.09. The database of these galaxies is taken from SDSS (Sloan Digital Sky Survey) 7th and 9th data release. We have converted two dimensional data to three dimensional by Godlowskian Transformation using position angle-inclination angle method. We intend to find non-random effects in the spatial orientation of galaxies in the Supercluster.  No preferred alignment of angular momentum vectors is noticed, supporting Hierarchy model of galaxy formation. BIBECHANA 17 (2020) 117-12

A spectroscopic study of the low redshift dwarf galaxy SDSS J134326.99+431118.7 to calculate star formation rate

We present a spectroscopic study of an interacting emission-line dwarf galaxy SDSS J134326.99+431118.7. We analyzed eight-strong emission lines of wavelength in a range of 3902.1Å to 6619.1Å. Among them, the strongest emission line is OIII, with an intensity of 1043.6 x 10-17 erg/s/cm2/Å. These characteristic lines show a perfect Gaussian fit with a coefficient of regression greater than 98%, where the derived full width half maximum (FWHM) is less than 3.8 Å. The line ratio between Ha  and Hb, (Ha/ Hb), is  2.73. This suggests that the galaxy is a starburst galaxy. Star Formation Rate (SFR) of the galaxy derived from Ha  emission line flux is 0.019  and emission line metallicity derived from flux ratio between NII and Ha is 7.85 dex. These morphological and physical properties of SDSSJ134326.99+431118.7 are very similar to those of a typical Blue Compact Dwarf (BCD) galaxy. We conclude that we have presented another evidence of forming a BCD-type galaxy through a merger. BIBECHANA 18 (1) (2021) 100-10

Spatial orientation of galaxies in supercluster S[227+006+0078]

We present a study of spin vector orientation of 1218 SDSS (Sloan Digital Sky Survey) galaxies in Supercluster S [227+006+0078] having redshift 0.07 to 0.09. The database of these galaxies is taken from SDSS (Sloan Digital Sky Survey) 7th and 9th data release. We have converted two dimensional data to three dimensional by Godlowskian Transformation using position angle-inclination angle method. We intend to find non-random effects in the spatial orientation of galaxies in the Supercluster.  No preferred alignment of angular momentum vectors is noticed, supporting Hierarchy model of galaxy formation. BIBECHANA 17 (2020) 117-12

A spectroscopic study of the low redshift dwarf galaxy SDSS J134326.99+431118.7 to calculate star formation rate

We present a spectroscopic study of an interacting emission-line dwarf galaxy SDSS J134326.99+431118.7. We analyzed eight-strong emission lines of wavelength in a range of 3902.1Å to 6619.1Å. Among them, the strongest emission line is OIII, with an intensity of 1043.6 x 10-17 erg/s/cm2/Å. These characteristic lines show a perfect Gaussian fit with a coefficient of regression greater than 98%, where the derived full width half maximum (FWHM) is less than 3.8 Å. The line ratio between Ha  and Hb, (Ha/ Hb), is  2.73. This suggests that the galaxy is a starburst galaxy. Star Formation Rate (SFR) of the galaxy derived from Ha  emission line flux is 0.019  and emission line metallicity derived from flux ratio between NII and Ha is 7.85 dex. These morphological and physical properties of SDSSJ134326.99+431118.7 are very similar to those of a typical Blue Compact Dwarf (BCD) galaxy. We conclude that we have presented another evidence of forming a BCD-type galaxy through a merger. BIBECHANA 18 (1) (2021) 100-10

Rejuvenating Star Formation Activity in an Early-type Dwarf Galaxy, LEDA 1915372, with Accreted HI Gas

We report a rare astrophysical phenomenon, in which an early-type dwarf galaxy (dE), LEDA 1915372, is accreting gas from a nearby star-forming dwarf galaxy, MRK 0689, and is rejuvenating star-formation activity at the center. Both LEDA 1915372 and MRK 0689 have similar brightness of $M_{r}$ = $-$16.99 and $-$16.78 mag, respectively. They are located in a small group environment, separated by a sky-projected distance of 20.27 kpc (up to 70 kpc in three dimension), and have a relative line-of-sight radial velocity of 6 km/s. The observation of 21 cm emission with the Giant Metrewave Radio Telescope provides strong evidence of interaction between the pair dwarf galaxies in terms of neutral hydrogen (HI) morphology and kinematics. In particular, the HI map reveals that the two galaxies are clearly connected by a gas bridge, and the gas components of both LEDA 1915372 and MRK 0689 share a common direction of rotation. We also find that the HI emission peak deviates from LEDA 1915372 toward its optical blue plume, suggesting a tidal origin of ongoing central star formation. Our findings provide a new path to the formation of blue-cored dEs.Comment: Accepted for publication in ApJ

An Extensive Catalog of Early-type Dwarf Galaxies in the Local Universe: Morphology and Environment

We present an extensive catalog of 5405 early-type dwarf (dE) galaxies located in the various environments, i.e., clusters, groups and fields, of the local universe ($z$ $<$ 0.01). The dEs are selected through visual inspection of the Legacy survey's $g$-$r$-$z$ combined tri-color images. The inspected area, covering a total sky area of 7643 deg$^{2}$, encompasses two local clusters, Virgo and Fornax, 265 groups, and the regions around 586 field galaxies of $M_{K}$ $<$ $-$21 mag. The catalog aims to be one of the most extensive and publicly accessible collections of data on dE, despite its complex completeness limits that may not accurately represent its statistical completeness. The strength of the catalog lies in the morphological characteristics, including nucleated, tidal, and ultradiffuse dE. The two clusters contribute nearly half (2437 out of 5405) dEs, and the 265 groups contribute 2103 dEs. There are 864 dEs in 586 fields, i.e., ~1.47 dEs per field. Using a standard definition commonly used in literature, we identify 100 ultra-diffuse galaxies (UDGs), which take ~2% of the dE population. We find that 40% of our sample dEs harbor a central nucleus, and among the UDG population, a majority, 79%, are nonnucleated. About 1.3 of dEs suffer from ongoing tidal disturbance by nearby massive galaxies, and only 0.03% show the sign of recent dwarf-dwarf mergers. The association between dEs and their nearest bright neighbor galaxies suggests that dEs are more likely created where their neighbors are non-star-forming ones.Comment: Accepted for publication in ApJ

Asymmetric mass-loss from the white dwarf WD 0253+209 : Secret revealed

Dust structures around the white dwarf WD 0253+209 is studied in 100 and 60 micron infrared image. These images are received from Infrared Astronomical Satellite Survey (IRAS Survey). The post Asymptotic Giant Branch (AGB) emission of the white dwarf's precursors' wind and the ambient interstellar matter is studied. The distribution of the relative flux density is studied and analyzed in the context of the dust color temperature, mass loading trend and the amount of total mass deposited due the interaction in the interstellar medium. The twisted curved emission structure at 100 micron in the region of interest is probably due to the interaction between the ambient interstellar medium and the He-flashes of the parent planetary nebula of the central white dwarf WD 0253+209. The total mass of the filamentary arc is found to be ~ 5 solar masses, as predicted. The mass loss rate of the post AGB star goes up to 10-5 solar masses per year. It is concluded that the first He-flash occurred at least ~2500 years ago. Keywords: white dwarf; interstellar medium; flux density; interstellar dust; mass of the gas DOI: http://dx.doi.org/10.3126/bibechana.v8i0.4806 BIBECHANA 8 (2012) 1-