A5030075074- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Economic and Fiscal Studies
- Geophysics and Gravity Measurements
- Chronic Obstructive Pulmonary Disease (COPD) Research
- Global Financial Crisis and Policies
- Cosmology and Gravitation Theories
- Chronic Disease Management Strategies
- Pulsars and Gravitational Waves Research
- Advanced optical system design
- Astrophysics and Cosmic Phenomena
- Advanced Statistical Methods and Models
- Global Health Care Issues
- Risk Management in Financial Firms
- Market Dynamics and Volatility
- Atmospheric Ozone and Climate
- Polish socio-economic development
- Monetary Policy and Economic Impact
Gdańsk Medical University
2011-2021
National Bank of Poland
2008-2015
Campbell Collaboration
2000-2009
Max Planck Society
2002-2008
Max Planck Institute for Astrophysics
2002-2008
Mineral Products Association
2000-2005
Lawrence Livermore National Laboratory
1999-2002
The Ohio State University
1997-1999
We report on our search for microlensing towards the Large Magellanic Cloud (LMC). Analysis of 5.7 years photometry 11.9 million stars in LMC reveals 13 - 17 events. This is significantly more than $\sim$ 2 to 4 events expected from lensing by known stellar populations. The timescales ($\that$) range 34 230 days. estimate optical depth with $2 < \that 400$ days be 1.2 ^{+0.4}_ {-0.3} \ten{-7}$, an additional 20% 30% systematic error. spatial distribution mildly inconsistent LMC/LMC disk...
We report on a search for long duration microlensing events towards the Large Magellanic Cloud. find none, and therefore put limits contribution of high mass objects to Galactic dark matter. At 95% confidence level we exclude in range 0.3 solar masses 30.0 from contributing more than 4 times 10^11 halo. Combined with earlier results, this means that under 30 cannot make up entire matter halo if is typical size. For halo, 10 contribute less 40%
We present the microlensing optical depth toward Galactic bulge based on detection of 99 events found in our Difference Image Analysis (DIA) survey. This analysis encompasses 3 yr data, covering ~17 million stars ~4 deg2, to a source-star baseline magnitude limit V = 23. The DIA technique improves quality photometry crowded fields, and allows us detect more with faint source stars. find that this method increases number by 85% compared standard technique. light curves are presented, fit...
Using 7 years of MACHO survey data, we present a new determination the optical depth to microlensing towards Galactic bulge. We select sample 62 events (60 unique) on clump giant sources and perform detailed efficiency analysis. use only because these are bright bulge stars not as strongly affected by blending other events. subsample 42 concentrated in just 4.5 square degrees, find tau = 2.17^{+0.47}_{-0.38} x 10^{-6} at (l,b) (1.50, -2.68), somewhat smaller than found most previous studies,...
The MACHO Project is a microlensing survey that monitors the brightnesses of ∼60 million stars in Large Magellanic Cloud (LMC), Small Cloud, and Galactic bulge. Our database presently contains about 80 billion photometric measurements, significant fraction all astronomical photometry. We describe calibration two‐color photometry transformation to standard Kron‐Cousins V R system. Calibrated may be properly compared with other observations on system, enhancing astrophysical value these data....
We present an analysis of the longest timescale microlensing events discovered by MACHO Collaboration during a 7 year survey Galactic bulge. find 6 that exhibit very strong parallax signals due, in part, to accurate photometric data from GMAN and MPS collaborations. The fit parameters are used likelihood analysis, which is able estimate distance masses lens objects based upon standard model velocity distribution. This indicates most likely 5 lenses > 1 Msun, suggests substantial fraction...
More than 1300 variables classified provisionally as first-overtone RR Lyrae pulsators in the MACHO variable-star database of Large Magellanic Cloud (LMC) have been subjected to standard frequency analysis. Based on remnant power prewhitened spectra, we found 70% total population be monoperiodic. The remaining 30% (411 stars) are one nine types according their spectra. Several pulsational behavior clearly identified here for first time. Together with earlier discovered double-mode...
We present the light curves of 21 gravitational microlensing events from first six years MACHO Project survey that are likely examples lensing by binary systems. These were manually selected a total sample ~350 candidate either detected Alert System or discovered through retrospective analyses database. At least 14 these exhibit strong (caustic) features, and four well fit with large mass ratio (brown dwarf planetary) systems, although fits not necessarily unique. The event rate is roughly...
We have frequency-analyzed 6391 variables classified earlier as fundamental-mode RR Lyrae (RR0) stars in the MACHO database on Large Magellanic Cloud (LMC). The overwhelming majority (i.e., 96%) of these been proved to be indeed RR0 stars, whereas remaining ones fallen into one following categories: single- and double-mode Cepheids, binaries, first-overtone nonclassified variables. Special attention has paid properties amplitude- phase-modulated (the Blazhko stars). found altogether 731...
We present 47 spectroscopically confirmed quasars discovered behind the Magellanic Clouds identified via photometric variability in MACHO database. Thirty-eight lie Large Cloud and nine Small Cloud, more than tripling number of previously known this region. The cover redshift interval 0.2 < z 2.8 have apparent mean magnitudes 16.6 ≤ 20.1. discuss details quasar candidate selection based on time database results spectroscopic follow-up observations. Our detection efficiency was 20%; primary...
We sing the praises of central limit theorem. Having previously removed all other possible causes significant systematic error in statistical parallax determination RR Lyrae absolute magnitudes, we investigate errors from two final sources input data: apparent magnitudes and extinctions. find corrections due to each ~0.05 mag, i.e., ~1/2 error. However, these are opposite sign so roughly cancel. The magnitude system that adopted Layden et al. was calibrated photometry Clube & Dawe. Using...
We present a 9 million star color-magnitude diagram (9M CMD) of the LMC bar. The 9M CMD reveals complex superposition different age and metallicity stellar populations, with important evolutionary phases occurring over 3 orders magnitude in number density. First, we count non-variable supergiants, associated Cepheids, measure effective temperatures defining instability strip. Lifetime predictions evolution theory are tested, implications for origin low-luminosity Cepheids. highly-evolved AGB...
The MACHO Project: Microlensing Detection Efficiency, C. Alcock, R. A. Allsman, D. Alves, T. S. Axelrod, Becker, P. Bennett, K. H. Cook, J. Drake, Freeman, M. Geha, Griest, Lehner, L. Marshall, Minniti, Nelson, B. Peterson, Popowski, Pratt, Quinn, W. Stubbs, Sutherland, Tomaney, Vandehei, Welch, (The Collaboration)
By cross-correlating the results of two recent large-scale surveys, general properties a well-defined sample semiregular variable stars have been determined. ISOGAL mid-infrared photometry (7 and 15 μm) MACHO V R light curves are assembled for approximately 300 in Baade's windows low extinction toward Galactic bulge. These mainly giants late M spectral type, evolving along asymptotic giant branch (AGB). They found to possess wide continuous distribution pulsation periods obey an approximate...
We report the discovery of eight new R Coronae Borealis (RCB) stars in Large Magellanic Cloud (LMC) using MACHO project photometry database. The these increases number known RCB LMC to thirteen. have also discovered four similar Galactic variable DY Per. These decline much more slowly and are cooler than stars. absolute luminosities unknown since there is no direct measurement distance any star. Hence, importance find a larger range magnitudes (M(V) = -2.5 -5 mag) inferred from small...
I demonstrate that the two unexpected results in local universe-(1) anomalous intrinsic (V-I&parr0;0 colors of clump giants and RR Lyrae stars Galactic center, (2) very short distances to Magellanic Clouds (LMC, SMC) as inferred from giants-are connected with each other. The anomaly is partially resolved by using photometry phase II Optical Gravitational Lensing Experiment (OGLE) rather than I. need for V- or I-magnitude-based change bulge one option explain remaining color discrepancy. Such...
We present mean reddenings toward 3525 RR0 Lyrae stars from the Galactic bulge fields of MACHO Survey. These are determined using color at minimum V-band light themselves and found to be in general agreement with extinction estimates same location obtained other methods. Using 3256 located Bulge, we derive selective coefficient RV,VR = AV/E(V − R) 4.3 ± 0.2. This value is what expected for a standard law RV,BV 3.1 0.3.
Shapes of RR Lyrae light curves can be described in terms Fourier coefficients that past research has linked with physical characteristics such as luminosity, mass, and temperature. have been derived for the V R 785 overtone variables 16 MACHO fields near bar LMC. In general, phase differences ϕ21, ϕ31, ϕ41 increase amplitude ratio R21 decreases increasing period. The both magnitudes follow these patterns, but are on average slightly greater, their amplitudes about 20% smaller, than ones...
BACKGROUND:Chronic obstructive pulmonary disease (COPD) is a common that occurs all over the world. Models of care, initially accessed from clinical point view, must also be evaluated in terms their economic effectiveness, as health care systems are limited. The Integrated Care Model (ICM) procedure dedicated to patients suffering advanced COPD offers home-oriented support multidisciplinary team. main aim present study was evaluate cost-effectiveness ICM. MATERIAL AND METHODS:We included 44...
We present a mathematical analysis of the statistical parallax method. The method yields physical insight into maximum-likelihood determinations luminosity and velocity distribution enables us to conduct vigorous Monte Carlo investigation various systematic effects. apply our analytic formalism RR Lyrae sample Layden et al. stars is highly non-Gaussian, with kurtoses Kπ = 2.04, Kθ 3.22, Kz 4.28 in three principal directions, but this has almost no effect on either best fit or uncertainty...
We present UBV photometry of the eclipsing binary Harvard Variable 2274 in Large Magellanic Cloud (LMC). The stellar parameters this system were recently calculated by Guinan et al., who gave both a reddening toward HV E(B-V) = 0.083 ± 0.006 and distance modulus to LMC μLMC 18.42 0.07. was also determined Udalski found 0.149 0.015. With al. B V photometry, obtained 0.12 0.009 18.30 Using our we derive 0.088 0.023, consistent with original value supporting longer about 18.40 stress...
We present photometry and analysis of the microlensing alert MACHO 96-LMC-2 (event LMC-14 in an earlier paper). This event was initially detected by Alert System subsequently monitored Global Microlensing Network (GMAN). The ~3% provided GMAN follow-up effort reveals a periodic modulation light curve. attribute this to binarity lensed source. fits rotating binary source magnified single lens converge on two minima, separated Δχ2 ~ 1. most significant fit X1 predicts primary which contributes...