705 citations · 12k across the 299 of their papers we have counts for
44 papers · 1 filter
Microlensing optical depth, event rate, and limits on compact objects in dark matter based on 20 yr of OGLE observations of the Small Magellanic Cloud
P. Mróz, A. Udalski, M. K. Szymański +12
Some previous studies have suggested that massive and intermediate-mass primordial black holes (PBHs) could comprise a substantial fraction of dark matter in the Universe. Such bla…
Analysis of the full Spitzer microlensing sample I: Dark remnant candidates and Gaia predictions
Krzysztof A. Rybicki, Yossi Shvartzvald, Jennifer C. Yee +70
In the pursuit of understanding the population of stellar remnants within the Milky Way, we analyze the sample of microlensing events observed by the Spitzer Space Teles…
Virial Black Hole Masses for AGNs behind the Magellanic Clouds
Swayamtrupta Panda, Szymon Kozłowski, Mariusz Gromadzki +13
We use the spectroscopic data collected by the Magellanic Quasars Survey (MQS) as well as the photometric V- and I-band data from the Optical Gravitational Lensing Experiment (OGLE…
Microlensing optical depth and event rate toward the Large Magellanic Cloud based on 20 years of OGLE observations
P. Mroz, A. Udalski, M. K. Szymanski +14
Measurements of the microlensing optical depth and event rate toward the Large Magellanic Cloud (LMC) can be used to probe the distribution and mass function of compact objects in…
No massive black holes in the Milky Way halo
P. Mroz, A. Udalski, M. K. Szymanski +13
The gravitational wave detectors have unveiled a population of massive black holes that do not resemble those observed in the Milky Way and whose origin is debated. According to on…
Expectations for time-delay measurements in active galactic nuclei with the Vera Rubin Observatory
Bozena Czerny, Swayamtrupta Panda, Raj Prince +10
The Vera Rubin Observatory will provide an unprecedented set of time-dependent observations of the sky. The planned Legacy Survey of Space and Time (LSST) operating for 10 years wi…
A three-dimensional map of the Milky Way using 66,000 Mira variable stars
Patryk Iwanek, Radosław Poleski, Szymon Kozłowski +13
We study the three-dimensional structure of the Milky Way using 65,981 Mira variable stars discovered by the Optical Gravitational Lensing Experiment (OGLE) survey. The spatial dis…
An isolated mass gap black hole or neutron star detected with astrometric microlensing
Casey Y. Lam, Jessica R. Lu, Andrzej Udalski +42
We present the analysis of five black hole candidates identified from gravitational microlensing surveys. Hubble Space Telescope astrometric data and densely sampled lightcurves fr…
A Survey Length for AGN Variability Studies
Szymon Kozłowski
The damped random walk (DRW) process is one of the most commonly used and simplest stochastic models to describe variability of active galactic nuclei (AGN). An AGN light curve can…
Properties of the Milky Way's Old Populations Based on Photometric Metallicities of the OGLE RR Lyrae Stars
P. Pietrukowicz, A. Udalski, I. Soszynski +11
We have used photometric data on almost 91 000 fundamental-mode RR Lyrae stars (type RRab) detected by the OGLE survey to investigate properties of old populations in the Milky Way…
Microlensing optical depth and event rate in the OGLE-IV Galactic plane fields
Przemek Mroz, Andrzej Udalski, Michal K. Szymanski +10
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…
Mapping the Northern Galactic Disk Warp with Classical Cepheids
D. M. Skowron, J. Skowron, P. Mróz +11
We present an updated three dimensional map of the Milky Way based on a sample of 2431 classical Cepheid variable stars, supplemented with about 200 newly detected classical Cephei…
Time delay measurement of Mg II line in CTS C30.10 with SALT
Bozena Czerny, Aleksandra Olejak, Mateusz Ralowski +18
We report 6 yr monitoring of a distant bright quasar CTS C30.10 (z = 0.90052) with the Southern African Large Telescope (SALT). We measured the rest-frame time-lag of da…
Discovery of two quasars at from the OGLE Survey
Szymon Kozłowski, Eduardo Bañados, A. Udalski +16
We have used deep Optical Gravitational Lensing Experiment (OGLE-IV) images ( mag, mag at ) of the Magellanic System, encompassing an area of $\s…
Rotation curve of the Milky Way from Classical Cepheids
P. Mroz, A. Udalski, D. M. Skowron +7
Flat rotation curves of spiral galaxies are considered as an evidence for dark matter, but the rotation curve of the Milky Way is difficult to measure. Various objects were used to…
Identification of blazar candidates behind Small and Large Magellanic Clouds
Natalia Żywucka, Arti Goyal, Marek Jamrozy +4
We report the identification of blazar candidates behind the Magellanic Clouds. The objects were selected from the Magellanic Quasars Survey (MQS), which targeted the entire Large…
Narrow-line Seyfert 1 galaxies in the context of the Quasar Main Sequence
Bozena Czerny, Swayamtrupta Panda, Marzena Sniegowska +4
Narrow-line Seyfert 1 galaxies are defined on the basis of their line widths, and they are generally considered to be high Eddington ratio sources. But in the context of the Quasar…
A three-dimensional map of the Milky Way using classical Cepheid variable stars
D. M. Skowron, J. Skowron, P. Mróz +9
The Milky Way is a barred spiral galaxy, with physical properties inferred from various tracers informed by the extrapolation of structures seen in other galaxies. However, the dis…
The Proper Motion Field of the Small Magellanic Cloud: Kinematic Evidence for its Tidal Disruption
Paul Zivick, Nitya Kallivayalil, Roeland P. van der Marel +9
We present a new measurement of the systemic proper motion of the Small Magellanic Cloud (SMC), based on an expanded set of 30 fields containing background quasars and spanning a $…
A Gravitationally Lensed Quasar Discovered in OGLE
Z. Kostrzewa-Rutkowska, S. Kozłowski, C. Lemon +15
We report the discovery of a new gravitationally lensed quasar (double) from the Optical Gravitational Lensing Experiment (OGLE) identified inside the 670 sq. deg area encomp…
OGLE Collection of Star Clusters. New Objects in the Magellanic Bridge and the Outskirts of the Small Magellanic Cloud
M. Sitek, M. K. Szymański, A. Udalski +13
The Magellanic System (MS) encompasses the nearest neighbors of the Milky Way, the Large (LMC) and Small (SMC) Magellanic Clouds, and the Magellanic Bridge (MBR). This system conta…
A Method to Measure the Unbiased Decorrelation Timescale of the AGN Variable Signal from Structure Functions
Szymon Kozłowski
A simple, model-independent method to quantify the stochastic variability of active galactic nuclei (AGNs) is the structure function (SF) analysis. If the SF for the timescales sho…
Limitations on the recovery of the true AGN variability parameters using Damped Random Walk modeling
Szymon Kozłowski
Context: The damped random walk (DRW) stochastic process is nowadays frequently used to model aperiodic light curves of AGNs. A number of correlations between the DRW model paramet…
OGLE-ing the Magellanic System: Three-Dimensional Structure of the Clouds and the Bridge Using RR Lyrae Stars
Anna M. Jacyszyn-Dobrzeniecka, D. M. Skowron, P. Mróz +10
We present a three-dimensional analysis of a sample of 22 859 type RR Lyrae stars in the Magellanic System from the OGLE-IV Collection of RR Lyrae stars. The distance to each…