Microlensing optical depth and event rate in the OGLE-IV Galactic plane fields

Searches for gravitational microlensing events are traditionally concentrated on the central regions of the Galactic bulge but many microlensing events are expected to occur in the Galactic plane, far from the Galactic Center. Owing to the difficulty in conducting high-cadence observations of the Galactic plane over its vast area, which are necessary for the detection of microlensing events, their global properties were hitherto unknown. Here, we present results of the first comprehensive search for microlensing events in the Galactic plane. We searched an area of almost 3000 square degrees along the Galactic plane (|b|<7, 0<l<50, 190<l<360 deg) observed by the Optical Gravitational Lensing Experiment (OGLE) during 2013-2019 and detected 630 events. We demonstrate that the mean Einstein timescales of Galactic plane microlensing events are on average three times longer than those of Galactic bulge events, with little dependence on the Galactic longitude. We also measure the microlensing optical depth and event rate as a function of Galactic longitude and demonstrate that they exponentially decrease with the angular distance from the Galactic Center (with the characteristic angular scale length of 32 deg). The average optical depth decreases from $0.5\times 10^{-6}$ at l=10 deg to $1.5\times 10^{-8}$ in the Galactic anticenter. We also find that the optical depth in the longitude range 240<l<330 deg is asymmetric about the Galactic equator, which we interpret as a signature of the Galactic warp.Comment: ApJS, in pres

Microlensing optical depth and event rate in the OGLE-IV Galactic plane fields

Searches for gravitational microlensing events are traditionally concentrated on the central regions of the Galactic bulge but many microlensing events are expected to occur in the Galactic plane, far from the Galactic Center. Owing to the difficulty in conducting high-cadence observations of the Galactic plane over its vast area, which are necessary for the detection of microlensing events, their global properties were hitherto unknown. Here, we present results of the first comprehensive search for microlensing events in the Galactic plane. We searched an area of almost 3000 square degrees along the Galactic plane (|b| < 7°, 0° < l < 50°, 190° < l < 360°) observed by the Optical Gravitational Lensing Experiment (OGLE) during 2013–2019 and detected 630 events. We demonstrate that the mean Einstein timescales of Galactic plane microlensing events are on average three times longer than those of Galactic bulge events, with little dependence on the Galactic longitude. We also measure the microlensing optical depth and event rate as a function of Galactic longitude and demonstrate that they exponentially decrease with the angular distance from the Galactic Center (with the characteristic angular scale length of 32°). The average optical depth decreases from 0.5 × 10⁻⁶ at l = 10° to 1.5 × 10⁻⁸ in the Galactic anticenter. We also find that the optical depth in the longitude range 240° < l < 330° is asymmetric about the Galactic equator, which we interpret as a signature of the Galactic warp

OGLE-2018-BLG-0532Lb: Cold Neptune With Possible Jovian Sibling

We report the discovery of the planet OGLE-2018-BLG-0532Lb, with very obvious signatures in the light curve that lead to an estimate of the planet-host mass ratio $q=M_{\rm planet}/M_{\rm host}\simeq 1\times10^{-4}$. Although there are no obvious systematic residuals to this double-lens/single-source (2L1S) fit, we find that $\chi^2$ can be significantly improved by adding either a third lens (3L1S, $\Delta\chi^2=81$) or second source (2L2S, $\Delta\chi^2=65$) to the lens-source geometry. After thorough investigation, we conclude that we cannot decisively distinguish between these two scenarios and therefore focus on the robustly-detected planet. However, given the possible presence of a second planet, we investigate to what degree and with what probability such additional planets may affect seemingly single-planet light curves. Our best estimates for the properties of the lens star and the secure planet are: a host mass $M\sim 0.25\,M_\odot$, system distance $D_L\sim 1\,$kpc and planet mass $m_{p,1}= 8\,M_\oplus$ with projected separation $a_{1,\perp}=1.4\,$au. However, there is a relatively bright $I=18.6$ (and also relatively blue) star projected within $<50\,$mas of the lens, and if future high-resolution images show that this is coincident with the lens, then it is possible that it is the lens, in which case, the lens would be both more massive and more distant than the best-estimated values above.Comment: 48 pages, 9 figures, 7 table

OGLE-2019-BLG-0960 Lb: The Smallest Microlensing Planet

We report the analysis of OGLE-2019-BLG-0960, which contains the smallest mass-ratio microlensing planet found to date (q = 1.2-1.6 × 10-5 at 1s). Although there is substantial uncertainty in the satellite parallax measured by Spitzer, the measurement of the annual parallax effect combined with the finite source effect allows us to determine the mass of the host star (M L = 0.3-0.6 M o?), the mass of its planet (m p = 1.4-3.1 M ?), the projected separation between the host and planet (a ? = 1.2-2.3 au), and the distance to the lens system (D L = 0.6-1.2 kpc). The lens is plausibly the blend, which could be checked with adaptive optics observations. As the smallest planet clearly below the break in the mass-ratio function, it demonstrates that current experiments are powerful enough to robustly measure the slope of the mass-ratio function below that break. We find that the cross-section for detecting small planets is maximized for planets with separations just outside of the boundary for resonant caustics and that sensitivity to such planets can be maximized by intensively monitoring events whenever they are magnified by a factor A \u3e 5. Finally, an empirical investigation demonstrates that most planets showing a degeneracy between (s \u3e 1) and (s \u3c 1) solutions are not in the regime (log s| » 0) for which the close / wide degeneracy was derived. This investigation suggests that there is a link between the close / wide and inner/outer degeneracies and also that the symmetry in the lens equation goes much deeper than symmetries uncovered for the limiting cases

Stability of green tea nanoscale zero-valent iron

Colloidal suspension of nano zero-valent iron (nZVI), obtained as a result of mixing green tea (GT) solution with iron solutions (FeCl2 and FeSO4 separately to form two suspensions: GT-nZVIFeCl2 and GT-nZVIFeSO4) was assessed in terms of stability. The particles of suspensions had a tendency rapidly aggregation to form larger aggregates, and then settled. The absolute value of zeta potential (ζ) of suspensions did not exceed 17 mV. To prevent the aggregation of nZVI particles, the pHs were changed by the addition of Na2CO3 to obtain higher values of ζ. For both suspensions, the zeta potential at a satisfactory level was obtained at pH values higher than 7.5. Then, the potential was lower than −40 mV for GT-nZVIFeCl2 and lower than −25mV for GT-nZVIFeSO4. This means that the first suspension had a better stability than second. The isoelectric point (IEP) of GT-nZVIFeCl2 was in the range from 4.5 to 5, while in the case of GT-nZVIFeSO4 all measured ζ were negative. To investigate the effect of increased ionic strength (IS) on the stability of suspensions at different pH values, NaCl and MgSO4 were added to the irons solutions. The final IS in the GT-nZVI was 12 mM. In both of the suspensions the absolute values of ζ were lower than previous and were about 25 and 20 mV, for GT-nZVIFeCl2 and GT-nZVIFeSO4, respectively

Stability of green tea nanoscale zero-valent iron

Colloidal suspension of nano zero-valent iron (nZVI), obtained as a result of mixing green tea (GT) solution with iron solutions (FeCl2 and FeSO4 separately to form two suspensions: GT-nZVIFeCl2 and GT-nZVIFeSO4) was assessed in terms of stability. The particles of suspensions had a tendency rapidly aggregation to form larger aggregates, and then settled. The absolute value of zeta potential (ζ) of suspensions did not exceed 17 mV. To prevent the aggregation of nZVI particles, the pHs were changed by the addition of Na2CO3 to obtain higher values of ζ. For both suspensions, the zeta potential at a satisfactory level was obtained at pH values higher than 7.5. Then, the potential was lower than −40 mV for GT-nZVIFeCl2 and lower than −25mV for GT-nZVIFeSO4. This means that the first suspension had a better stability than second. The isoelectric point (IEP) of GT-nZVIFeCl2 was in the range from 4.5 to 5, while in the case of GT-nZVIFeSO4 all measured ζ were negative. To investigate the effect of increased ionic strength (IS) on the stability of suspensions at different pH values, NaCl and MgSO4 were added to the irons solutions. The final IS in the GT-nZVI was 12 mM. In both of the suspensions the absolute values of ζ were lower than previous and were about 25 and 20 mV, for GT-nZVIFeCl2 and GT-nZVIFeSO4, respectively

Coal recovery from a coal waste dump

The possibilities and efficiency of coal recovery from the waste material located at the Central Coal Waste Dump in Poland were presented in this paper. The waste material includes significant amount of fly ash. Research conducted into determination of energetic properties of such wastes showed that the average ash content was 75.75% and the average gross calorific value was 7.81 MJ/kg. Coal was gravitationally separated from the waste material in a pulsatory jig and in a spiral washer including size fractions: 30-5 and 8-0 mm (this was crushed to a size <3.2 mm), respectively. The application of the pulsatory jig (pulse classifier) allowed to obtain a high-quality energetic concentrate with the ash content lower than 12% and the gross calorific value higher than 26 MJ/kg (with average yield 7.8%). The spiral separator gave much worse results. The average gross calorific value for the concentrate was 11.6 MJ/kg, with the high ash content 56.5% and yield approximately 26%

Coal recovery from a coal waste dump

The possibilities and efficiency of coal recovery from the waste material located at the Central Coal Waste Dump in Poland were presented in this paper. The waste material includes significant amount of fly ash. Research conducted into determination of energetic properties of such wastes showed that the average ash content was 75.75% and the average gross calorific value was 7.81 MJ/kg. Coal was gravitationally separated from the waste material in a pulsatory jig and in a spiral washer including size fractions: 30-5 and 8-0 mm (this was crushed to a size <3.2 mm), respectively. The application of the pulsatory jig (pulse classifier) allowed to obtain a high-quality energetic concentrate with the ash content lower than 12% and the gross calorific value higher than 26 MJ/kg (with average yield 7.8%). The spiral separator gave much worse results. The average gross calorific value for the concentrate was 11.6 MJ/kg, with the high ash content 56.5% and yield approximately 26%

Cost-effectiveness of radial vs. femoral approach in primary percutaneous coronary intervention in STEMI – Randomized, control trial

Introduction and objectives: Primary percutaneous coronary intervention infarction became the preferred method of treatment for myocardial ST segment elevation. Improved safety was reported in transradial access (radial) compared to transfemoral access (femoral). The aim of this study was to compare the cost between the two access points in ST segment elevation myocardial infarction. Methods: This is a subanalysis of the OCEAN RACE trial in which 103 myocardial infarction patients were randomized to either the radial (n=52) or femoral (n=51) groups. The clinical safety and efficacy were recorded during the hospital stay. The procedural metrics were meticulously logged, and costs were evaluated using the micro-cost method. The indirect costs were estimated using the human capital approach. Results: Clinical success was numerically higher in the radial group (90.4 vs. 80.4%, p=0.123). There were no differences in major adverse cardiac events (9.6% vs. 11.8%, p=0.48) and death (2.0% vs. 6.0%, p=0.31). The average in-hospital cost per patient was 2,740 ± 1,092 EUR. The cost of therapeutic success was lower in the radial group at 3,060 EUR vs. 3,374 EUR. The indirect costs related to absence at work were 138 EUR per patient, which were lower in the radial group compared to the femoral group. Conclusions: The total in-hospital costs were similar between the study groups. The indirect costs were lower in the radial group. Introduction of radial access as the default approach in all centers may significantly reduce the overall financial burden from a social perspective