588 citations · 5.8k across the 140 of their papers we have counts for
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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…
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…
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…
Time Delay of MgII Emission Response for the Luminous Quasar HE 0435-4312: Towards Application of High-Accretor Radius-Luminosity Relation in Cosmology
Michal Zajaček, Bożena Czerny, Mary Loli Martinez-Aldama +21
Using the six years of the spectroscopic monitoring of the luminous quasar HE 0435-4312 () with the Southern African Large Telescope (SALT), in combination with the photo…
Time-delay measurement of MgII broad line response for the highly-accreting quasar HE 0413-4031: Implications for the MgII-based radius-luminosity relation
Michal Zajaček, Bożena Czerny, Mary Loli Martinez-Aldama +16
We present the monitoring of the AGN continuum and MgII broad line emission for the quasar HE 0413-4031 () based on the six-year monitoring by the South African Large Teles…
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…
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…
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…
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…
OGLE Collection of Star Clusters. New Objects in the Outskirts of the Large Magellanic Cloud
M. Sitek, M. K. Szymański, D. M. Skowron +13
The Magellanic System (MS), consisting of the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC) and the Magellanic Bridge (MBR), contains diverse sample of star cluste…
OGLE Study of the Sagittarius Dwarf Spheroidal Galaxy and its M54 Globular Cluster
A. Hamanowicz, P. Pietrukowicz, A. Udalski +9
We use the fundamental-mode RR Lyr-type variable stars (RRab) from OGLE-IV survey to draw a 3D picture of the central part of the tidally disrupted Sagittarius Dwarf Spheroidal (Sg…
OGLE-ing the Magellanic System: Three-Dimensional Structure of the Clouds and the Bridge Using Classical Cepheids
Anna M. Jacyszyn-Dobrzeniecka, D. M. Skowron, P. Mróz +10
We analyzed a sample of 9418 fundamental-mode and first-overtone Classical Cepheids from the OGLE-IV Collection of Classical Cepheids. The distance to each Cepheid was calculated u…
Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way
L. M. Howes, A. R. Casey, M. Asplund +22
The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars…
OGLE-IV Real-Time Transient Search
L. Wyrzykowski, Z. Kostrzewa-Rutkowska, S. Kozlowski +11
We present the design and first results of a real-time search for transients within the 650 sq. deg. area around the Magellanic Clouds, conducted as part of the OGLE-IV project and…
The Optical Gravitational Lensing Experiment: Analysis of the bulge RR Lyrae population from the OGLE-III data
P. Pietrukowicz, A. Udalski, I. Soszynski +8
We have analyzed the data on 16,836 RR Lyrae (RR Lyr) variables observed toward the Galactic bulge during the third phase of the Optical Gravitational Lensing Experiment (OGLE-III)…
Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. II. Ages, metallicities, detailed elemental abundances, and connections to the Galactic thick disc
T. Bensby, S. Feltzing, J. A. Johnson +13
The Bulge is the least understood major stellar population of the Milky Way. Most of what we know about the formation and evolution of the Bulge comes from bright giant stars. The…
The Extreme Microlensing Event OGLE-2007-BLG-224: Terrestrial Parallax Observation of a Thick-Disk Brown Dwarf
A. Gould, A. Udalski, B. Monard +10
Parallax is the most fundamental technique to measure distances to astronomical objects. Although terrestrial parallax was pioneered over 2000 years ago by Hipparchus (ca. 140 BCE)…
Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. Detailed abundance analysis of OGLE-2008-BLG-209S
T. Bensby, J. A. Johnson, J. Cohen +7
AIMS. Our aims are twofold. First we aim to evaluate the robustness and accuracy of stellar parameters and detailed elemental abundances that can be derived from high-resolution sp…