Medium resolution near-infrared spectra of the host galaxies of nearby quasars

We present medium resolution near-infrared host galaxy spectra of low redshift quasars, PG 0844+349$0844+349$ (z = 0.064), PG 1226+023$1226+023$ (z = 0.158), and PG 1426+015$1426+015$ (z = 0.086). The observations were done by using the Infrared Camera and Spectrograph (IRCS) at the Subaru 8.2 m telescope. The full width at half maximum of the point spread function was about 0.3 arcsec by operations of an adaptive optics system, which can effectively resolve the quasar spectra from the host galaxy spectra. We spent up to several hours per target and developed data reduction methods to reduce the systematic noises of the telluric emissions and absorptions. From the obtained spectra, we identified absorption features of Mg I (1.503 μm), Si I (1.589 μm) and CO (6-3) (1.619 μm), and measured the velocity dispersions of PG 0844+349$0844+349$ to be 132 ± 110 km s⁻¹ and PG 1426+015$1426+015$ to be 264 ± 215 km s⁻¹. By using an _MBH–σ$M_{\text{BH}}''–''\sigma$ relation of elliptical galaxies, we derived the black hole (BH) mass of PG 0844+349$0844+349$, log(_MBH/_M⊙)=7.7±5.5$\log (M_{\text{BH}}/M_{\odot })=7.7\pm 5.5$ and PG 1426+015,log(_MBH/_M⊙)=9.0±7.5$1426+015\text{,}\log (M_{\text{BH}}/M_{\odot })=9.0\pm 7.5$. These values are consistent with the BH mass values from broad emission lines with an assumption of a virial factor of 5.5.     

The relation between the Black hole mass and the Bulge mass for low redshift AGNs. Part I: Ground-based observations

Using the bulge data from AGN image decomposition with ground-based observations, we calculate the ratios of the central supermassive black hole mass(SMBH) to the Bulge mass (_Mbh/_Mbulge$M_{\text{bh}}/M_{\text{bulge}}$) in a sample of X-ray selected AGNs, including 15 Narrow-line Seyfert 1 galaxies (NLS1s) and 18 broad-line Seyfert 1 galaxies (BLS1s). We found that the mean value of log(_Mbh/_Mbulge)$\log (M_{\text{bh}}/M_{\text{bulge}})$ is -3.81±0.11$-3.81\pm 0.11$ for 15 NLS1s, and -2.91±0.13$-2.91\pm 0.13$ for 18 BLS1s, showing the lower _Mbh/_Mbulge$M_{\text{bh}}/M_{\text{bulge}}$ in NLS1s relative to BLS1s. The calculation shows that the Bulge mass from the host image decomposition in NLS1s is statistically smaller than that from Hubble-type correction method, and a linear mass relation is suggested for NLS1s and a nonlinear mass relation for BLS1s. The studying of host galaxies with ground-based observations strongly limited by the atmospheric seeing. We need to do the decomposition of host images for NLS1s with Hubble Space Telescope observation in the future.     

The effects of CO2 on growth and transpiration of radish (Raphanus sativus) in hypobaria

Plants grown on long-term space missions will likely be grown in low pressure environments (i.e., hypobaria). However, in hypobaria the transpiration rates of plants can increase and may result in wilting if the water is not readily replaced. It is possible to reduce transpiration by increasing the partial pressure of CO₂ (pCO₂), but the effects of pCO₂ at high levels (>120 Pa) on the growth and transpiration of plants in hypobaria are not known. Therefore, the effects of pCO₂ on the growth and transpiration of radish (Raphanus sativus var. Cherry Bomb II) in hypobaria were studied. The fresh weight (FW), leaf area, dry weight (DW), CO₂ assimilation rates (C_A), dark respiration rates (DR), and transpiration rates from 26 day-old radish plants that were grown for an additional seven days at different total pressures (33, 66 or 101 kPa) and pCO₂ (40 Pa, 100 Pa and 180 Pa) were measured. In general, the dry weight of plants increased with CO₂ enrichment and with lower total pressure. In limiting pCO₂ (40 Pa) conditions, the transpiration for plants grown at 33 kPa was approximately twice that of controls (101 kPa total pressure with 40 Pa pCO₂). Increasing the pCO₂ from 40 Pa to 180 Pa reduced the transpiration rates for plants grown in hypobaria and in standard atmospheric pressures. However, for plants grown in hypobaria and high pCO₂ (180 Pa) leaf damage was evident. Radish growth can be enhanced and transpiration reduced in hypobaria by enriching the gas phase with CO₂ although at high levels leaf damage may occur.     

Plants survive rapid decompression: Implications for bioregenerative life support

Radish (Raphanus sativus), lettuce (Latuca sativa), and wheat (Triticum aestivum) plants were grown at either 98 kPa (ambient) or 33 kPa atmospheric pressure with constant 21 kPa oxygen and 0.12 kPa carbon dioxide in atmospherically closed pressure chambers. All plants were grown rockwool using recirculating hydroponics with a complete nutrient solution. At 20 days after planting, chamber pressures were pumped down as rapidly as possible, reaching 5 kPa after about 5 min and ∼1.5 kPa after about 10 min. The plants were held at 1.5 kPa for 30 min and then pressures were restored to their original settings. Temperature (22 °C) and humidity (65% RH) controls were engaged throughout the depressurization, although temperatures dropped to near 16 °C for a brief period. CO₂ and O₂ were not detectable at the low pressure, suggesting that most of the 1.5 kPa atmosphere consisted of water vapor. Following re-pressurization, plants were grown for another 7 days at the original pressures and then harvested. The lettuce, radish, and wheat plants showed no visible effects from the rapid decompression, and there were no differences in fresh or dry mass when compared to control plants maintained continuously at 33 or 98 kPa. But radish storage root fresh mass and lettuce head fresh and dry masses were less at 33 kPa compared to 98 kPa for both the controls and decompression treatment. The results suggest that plants are extremely resilient to rapid decompression, provided they do not freeze (from evaporative cooling) or desiccate. The water of the hydroponic system was below the boiling pressure during these tests and this may have protected the plants by preventing pressures from dropping below 1.5 kPa and maintaining humidity near 1.5 kPa. Further testing is needed to determine how long plants can withstand such low pressure, but the results suggest there are at least 30 min to respond to catastrophic pressure losses in a plant production chamber that might be used for life support in space.     

Observations of supergiant fast X-ray transients with LOFT

Supergiant fast X-ray transients are a subclass of high mass X-ray binaries displaying a peculiar and still poorly understood extreme variability in the X-ray domain. These sources undergo short sporadic outbursts (_LX∼$L_{\text{X}}\sim$ 10³⁶–10³⁷ erg s⁻¹), lasting few ks at the most, and spend a large fraction of their time in an intermediate luminosity state at about _LX∼$L_{\text{X}}\sim$ 10³³–10³⁴ erg s⁻¹. The sporadic and hardly predictable outbursts of supergiant fast X-ray transients were so far best discovered by large field of view (FOV) coded-mask instruments; their lower luminosity states require, instead, higher sensitivity focusing instruments to be studied in sufficient details. In this contribution, we provide a summary of the current knowledge on supergiant fast X-ray transients and explore the contribution that the new space mission concept LOFT, the Large Observatory for X-ray Timing, will be able to provide in the field of research of these objects.     

Merged series of normalized water leaving radiances obtained from multiple satellite missions for the Mediterranean Sea

Merging time series of ocean color-derived products provided by independent satellite missions supports related biogeochemical and environmental applications by combining temporally overlapping data sets and by increasing data coverage. The creation of a merged series of normalized water leaving radiances _LWN$L_{\text{WN}}$, the primary ocean color product, is presented for the Mediterranean Sea using the SeaWiFS and MODIS data records. The merging relies on an optically-based technique that combines the available _LWN$L_{\text{WN}}$ signal in a spectrally consistent way. Validation statistics indicate uncertainties associated with the merged _LWN$L_{\text{WN}}$ decreasing from 23% at 412 nm to 12% in the 500- to 555-nm spectral range. The inter-comparison of the sensor-specific products, conducted at the scale of the basin for daily-to-monthly time scales, indicates an overall consistency. The level of differences varies with the wavelength considered and shows a marked seasonal cycle, with differences that tend to be higher in winter. The merged series is remarkably consistent with the sensor-specific data, with average absolute percent differences lower than 10% for all wavelengths below 555 nm. The benefit of merging in terms of sampling frequency over the basin is also illustrated. A merged series of _LWN$L_{\text{WN}}$ data based on the two considered missions provides valid data over 36% of the basin area on a daily basis.     

Semi-empirical model of the maximum electron concentration in the ionosphere: Comparison with data from Toluca (México)

A simple semi-empirical model to determine the maximum electron concentration in the ionosphere (_NmF2$N_m{F}_2$) for South American locations is used to calculate _NmF2$N_m{F}_2$ for a northern hemisphere station in the same longitude sector. _NmF2$N_m{F}_2$ is determined as the sum of two terms, one related to photochemical and diffusive processes and the other one to transport mechanisms. The model gives diurnal variations of _NmF2$N_m{F}_2$ representative for winter, summer and equinox conditions, during intervals of high and low solar activity. Model _NmF2$N_m{F}_2$ results are compared with ionosonde observations made at Toluca-México (19.3°N; 260°E). Differences between model results and observations are similar to those corresponding to comparisons with South American observations. It seems that further improvement of the model could be made by refining the latitude dependencies of coefficients used for the transport term.     

On the effects of each term of the geopotential perturbation along the time I: Quasi-circular orbits

This paper provides a useful new method to determine minimum and maximum range of values for the degree and order of the geopotential coefficients required for simulations of orbits of satellites around the Earth. The method consists in a time integration of the perturbing acceleration coming from each harmonic of the geopotential during a time interval T. More precisely, this integral represents the total velocity contribution of a specific harmonic during the period T  . Therefore, for a pre-fixed minimum contribution, for instance 1×10^-8$1\times {10}^{-8}$ m/s during the period of time T, any harmonic whose contribution is below this value can, safely, be neglected. This fact includes some constraints in the degree and order of the terms which are present in the geopotential formula, saving computational efforts compared to the integration of the full model. The advantage of this method is the consideration of other perturbations in the dynamics (we consider the perturbations of the Sun, the Moon, and the direct solar radiation pressure with eclipses), since these forces affect the value of the perturbation of the geopotential, because these perturbations depend on the trajectory of the spacecraft, that is dependent on the dynamical model used. In this paper, we work with quasi-circular orbits and we present several simulations showing the bounds for the maximum degree and order (M) that should be used in the geopotential for different situations, e. g., for a satellite near 500 km of altitude (like the GRACE satellites at the beginning of their mission) we found 35?M?198$35?M?198$ for T=1$T=1$ day. We analyzed the individual contribution of the second order harmonic (_J2$J_2$) and we use its behavior as a parameter to determine the lower limit of the number of terms of the geopotential model. In order to test the accuracy of our truncated model, we calculate the mean squared error between this truncated model and the “full” model, using the CBERS (China-Brazil Earth Resources Satellite) satellite in this test.