Galaxian Contamination in Galactic Reddening Maps

Estimating the amount of foreground extinction due to the Milky Way dust along the line of sight is often a first step in determining the luminosity of an object. The amount of Galactic dust inferred by infrared emission maps can be contaminated by infrared light from nearby galaxies. By comparing extinction values at and around the location of nearby galaxies, we compile a list of 95 galaxies that likely contaminate the maps with an excess or improperly subtracted galaxian infrared emission, and tabulate our recommended values for the MW contribution. In addition to M82, which inspired this work, six more sources have an excess visual extinction A V of at least 0.05 mag greater than our annular values; including M83, NGC 1313, NGC 6822, NGC 918, UGC 11501, and UGC 11797. M33 is shown to be oversubtracted. NGC 88 and the outskirts of NGC 4258 are located in gaps in the Infrared Astronomical Satellite imaging. The recommended dust map values for the LMC, SMC, and M31 may also not be correctly returned by some software packages. Accurate reddening estimates are important for measuring stellar and supernova luminosities in these nearby galaxies.

Study of Dust Cavity around the White Dwarf WD 0352-049 in Infrared Astronomical Satellite Map

In this work, we have studied the far-infrared images of the dust cavity around the White Dwarf WD 0352-049 available in Infrared Astronomical Satellite Map from Sky View Observatory. The size of the cavity is 24.48 pc × 8.10 pc. We have studied the relative infrared flux density and calculated the dust color temperature and dust mass. The temperature of the whole cavity structure lies between a maximum value 24.09 ± 0.50 K to a minimum 21.87 ± 0.61K with fluctuation of 2.22 K and an average value of 23.09 ± 1.11 K. The small fluctuation of dust color temperature suggests that the dust in cavity structure is evolving independently and less disturbed from background radiation sources. The color map shows the identical distribution of flux at 60 μm and 100 μm and the inverse distribution of dust color temperature and dust mass. There is a Gaussian-like distribution of relative flux density, dust color temperature and dust mass. The Gaussian distribution of temperature suggests that the dusts in cavity are in local thermodynamic equilibrium. The study of relative flux density and dust color temperature along the major and minor axis shows there is a sinusoidal fluctuation of flux and temperature, which might be due to the wind generated by White Dwarf located nearby the center of the cavity structure. The total dust mass of the dust is found to be 0.07 Mʘ and that of gas is 13.66 Mʘ. The Jeans mass of the structure is less than the total mass of gas in the structure, suggesting the possibility of star formation activity by gravitational collapse in the future. Also, the study of inclination angle suggests that the three-dimensional shape of the structure is uniform and regularly shaped.

Study of Dust Properties of two Far Infrared Cavities near by Asymptotic Giant Branch stars under Infrared Astronomical Satellite Maps

The physical properties such as dust color temperature, dust mass, visual extinction, and Planck function with their distribution in the core region of two far-infrared cavities, namely FIC16-37 (size ~ 4.79 pc x 3.06 pc) located at R.A. (J2000): 16h 33m 57.25s & Dec. (J2000): -37d 47m 04.3s, and FIC12-58 (size ~ 22.54 pc x 14.84 pc) located at R.A. (J2000): 12h 52m 50.08s & Dec. (J2000): -58d 08m 55.02s, found within a galactic plane -10o to +10o nearby Asymptotic Giant Branch (AGB) stars namely AGB15-38 (R.A. (J2000): 15h 37m 40.74s & Dec. (J2000): -38d 20m 24.6s), and AGB12-57 (R.A (J2000): 12h 56m 38.50s & Dec. (J2000): -57d 54m 34.70s), respectively were studied using Infrared Astronomical Satellite (IRAS) survey. The dust color temperature was found to lie in the range of 23.95 ± 0.25 K to 23.44 ± 0.27 K with an offset about 0.5 K for FIC16-37, and 24.88 ± 0.27 K to 23.63 ± 0.98 K with an offset about 1 K for FIC12-58. The low offset in the dust color temperature indicated the symmetric distribution of density and temperature. The total mass of the cavities FIC16-37 and FIC12-58 were found to be 0.053 M☉ and 0.78 M☉, respectively. The contour plots of mass distribution of both of the cavities was found to follow the cosmological principle, suggesting the homogeneous and isotropic distribution of dust masses. The plot between temperature and visual extinction showed a negative correlation, suggesting that higher temperature has lower visual extinction and vice-versa. The distribution of Planck function along major and minor diameters of both of the cavities was found to be non-uniform, indicating oscillation of dust particles to get dynamical equilibrium. It further suggested the role of pressure-driven events nearby both cavities and suggested that dust particles are not in thermal equilibrium along the diameters.

Study of dust color temperature and visual extinction distribution of a far infrared cavity at 60 and 100 µm IRAS map around the AGB star at galactic latitude 8.6⁰

The dust-grain structure in the far infrared region under IRAS (Infrared Astronomical Satellite) Survey was studied using sky view virtual observatory. In order to find the possible far infrared cavity, we used SIMBAD database. In this paper, we discuss about the dusty environment of a far infrared cavity around the AGB star located at R.A. (J2000) =01h 41m 01s and Dec (J2000) = 71o 04’ 00” lying within far infrared loop G125+09 in the far infrared IRAS maps. A cavity like structure (major diameter ∼ 2.55 pc & minor diameter ∼ 0.77 pc) is found to lie at R.A. (J2000)= 01h 46m 57.2s and DEC (J2000)= 71o 24’ 57.1”, located at a distance ∼ 220 pc from the star. We studied the distribution of flux density, dust color temperature, dust mass, inclination angle, visual extinction and FIR spectral distribution of the cavity. We further studied the distribution of Planck function along extension and compression. The dust color temperature is found to lie in the range (19.7±0.65) K to 21.1±0.35) K which shows the cavity is isolated and stable. Product of visual extinction and dust color temperature is found to be less than one. A possible explanation of the results will be discussed. BIBECHANA 17 (2020) 42-49

Method of the Mission Planning for the Communication between the Small Satellite Clusters

Mission planning of space astronomical satellite is a complex optimization problem, which is to determine the communication activities needed by space astronomical and research the in-orbit plan. By abstracting the relevant elements of the mission planning problems of space astronomical satellite and establishing the mathematical model of mission planning of the space astronomical satellite, we introduce the Genetic Algorithm and design the single-objective Genetic Algorithm based on the communication mission window. In addition, based on the Genetic Algorithm, a multi-objective Genetic Algorithm based on the sequence of communication window is designed, which improves the coding ability of Genetic Algorithm and improves the flexibility and applicability of planning effect. From the results of planning simulation, this paper not only innovatively introduces Genetic Algorithm into mission planning of satellite and ground data in order to improve the efficiency of mission planning of space astronomical satellite, but also optimizes single-objective mission to multi-objective mission, which improves the applicability of mission planning of satellite communication and provides reference for other relevant researches in the future.

X-ray - Infrared relation of AGNs and search for highly obscured accretion in the AKARI NEP Field

The infrared Astronomical Satellite AKARI conducted deep (∼0.4 deg2) and wide (∼ 5.4 deg2) surveys around the North Ecliptic Pole (NEP) with its InfraRed Camera (IRC) with nine filters continuously covering the 2–25 μm range. These photometric bands include three filters that fill the “ Spitzer gap” between the wavelength coverages of IRAC and MIPS. This unique feature has enabled us to make sensitive mid-infrared detection of AGN candidates at z∼1-2, based on the Spectral Energy Distribution (SED) fitting including hot dust emission in the AGN torus. This enables us to compare X-rays and the AGN torus component of the infrared emission to help us identify highly absorbed AGNs, including Compton-thick ones. We report our results of the Chandra observation of the AKARI NEP Deep Field and discuss the prospects for upcoming Spectrum-RG (eROSITA+ART-XC) on the AKARI Wide field.

A Concept of Suborbital Scientific Mission and Technology Validation

Suborbital platforms are one of alternatives for satellites. They offer cheaper access to space to perform broad range of scientific and technology R&D. One of suborbital platforms are sounding rockets, which are suitable for these applications. A concept of scientific mission utilizing the sounding rocket is presented by author in this paper. The novelty of this mission is the operational responsive launch approach, which presents the example of the mission which responds for payload user needs, not payload contest approach, which is often in scientific community competing for payload space in space agency sounding rocket launch campaigns. The main mission goal is to perform astronomical observation of NEO using IR/VIS telescope. The secondary goal is to qualify the instrument for use on astronomical satellite observatory and raise its technology readiness level from TRL 6 to TRL 8. The expected mission output is to gain scientific data on NEO object and perform new IR/VIS optoelectronic instrument technology validation.