A5069216693- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Adaptive optics and wavefront sensing
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- History and Developments in Astronomy
- Particle Accelerators and Free-Electron Lasers
- Atmospheric and Environmental Gas Dynamics
- Solar and Space Plasma Dynamics
- Space Exploration and Technology
- Planetary Science and Exploration
- Geophysics and Gravity Measurements
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Isotope Analysis in Ecology
- Cosmology and Gravitation Theories
- Mechanics and Biomechanics Studies
- Radio Astronomy Observations and Technology
- Photocathodes and Microchannel Plates
University of Warsaw
2015-2024
California Institute of Technology
2020-2022
Campbell Collaboration
2016-2018
Max Planck Institute for Astronomy
2018
Max Planck Society
2018
Optica
2016
Abstract We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). used Hubble Space Telescope (HST) to carry out precise astrometry source star long-duration ( t E ≃ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462 (hereafter designated as MOA-11-191/OGLE-11-462), in direction Galactic bulge. HST imaging, conducted at eight epochs over interval 6 yr, reveals a clear relativistic astrometric deflection...
Abstract We present the analysis of five black hole candidates identified from gravitational microlensing surveys. Hubble Space Telescope astrometric data and densely sampled light curves ground-based surveys are fit with a single-source, single-lens model in order to measure mass luminosity each lens determine if it is hole. One targets (OGLE-2011-BLG-0462/MOA-2011-BLG-191 or OB110462 for short) shows significant >1 mas coherent shift, little no flux, has an inferred 1.6–4.4 M ⊙ . This...
Abstract Measurements of the microlensing optical depth and event rate toward Large Magellanic Cloud (LMC) can be used to probe distribution mass function compact objects in direction that galaxy—in Milky Way disk, dark matter halo, LMC itself. The previous measurements, based on small statistical samples events, found is an order magnitude smaller than expected from entire halo form objects. However, these studies were not sensitive long-duration events with Einstein timescales longer 2.5–3...
We present a detailed elemental abundance study of 90 F and G dwarf, turn-off, subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages abundances for 11 elements (Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Zn, Y Ba) have been determined. Four main findings are presented: (1) wide metallicity distribution with distinct peaks at [Fe/H] = −1.09, −0.63, −0.20, + 0.12, 0.41; (2) ahigh fraction intermediate-age to young where > 0...
Most stellar remnants so far have been found in binary systems, where they interact with matter from their companions. Isolated neutron stars and black holes are difficult to find as dark, yet predicted exist our Galaxy vast numbers. We explored the OGLE-III data base of 150 million objects observed years 2001–2009 59 microlensing events exhibiting a parallax effect due Earth's motion around Sun. Combining brightness measurements light curves expected proper motions Milky Way, we identified...
We combine Spitzer and ground-based observations to measure the microlens parallax vector , thus mass distance of OGLE-2014-BLG-0124L, making it first microlensing planetary system with a space-based measurement. The planet star have masses m ∼ 0.5 Mjup M 0.7 M☉ are separated by a⊥ 3.1 AU in projection. main source uncertainty all these numbers (approximately 30%, 20%) is relatively poor measurement Einstein radius θE, rather than πE, which measured 2.5% precision. This compares 22% based on...
We present a statistical analysis of the first four seasons from "second-generation" microlensing survey for extrasolar planets, consisting near-continuous time coverage 8 deg$^2$ Galactic bulge by OGLE, MOA, and Wise surveys. During this period, 224 events were observed all three groups. Over 12% showed deviation single-lens microlensing, $\sim$1/3 those anomaly is likely caused planetary companion. For each we have performed numerical ray-tracing simulations to calculate detection...
We have analyzed a sample of 27,258 fundamental-mode RR Lyrae variable stars (type RRab) detected recently toward the Galactic bulge by Optical Gravitational Lensing Experiment (OGLE) survey. The data support our earlier claim that these metal-poor trace closely barred structure formed intermediate-age red clump giants. distance to center (GC) inferred from is R_0=8.27+/-0.01(stat)+/-0.40(sys) kpc. show their spatial distribution has shape triaxial ellipsoid with an major axis located in...
Impolite planet ignores host's partner Many known exoplanets (planets outside our own solar system) are hosted by binary systems that contain two stars. These planets normally circle around both of their Using microlensing data taken with a worldwide network telescopes, Gould et al. found twice the mass Earth circles just one pair The same approach has potential to uncover other similar star and help illuminate some mysteries formation. Science , this issue p. 46
We report the detection of a Cold Neptune m_planet=21+/-2MEarth orbiting 0.38MSol M dwarf lying 2.5-3.3 kpc toward Galactic center as part campaign combining ground-based and Spitzer observations to measure distribution planets. This is first time that complex real-time protocols described by Yee et al. (2015), which aim maximize planet sensitivity while maintaining sample integrity, have been carried out in practice. Multiple survey follow-up teams successfully combined their efforts within...
We analyze an ensemble of microlensing events from the 2015 Spitzer campaign, all which were densely monitored by ground-based high-cadence survey teams. The simultaneous observations and ground yield measurements parallax vector $\pi_{\rm E}$, compact constraints on microlens properties are derived, including $\lesssim$25\% uncertainties lens mass distance. With current sample, we demonstrate that majority microlenses indeed in range M dwarfs. planet sensitivities 41 sample calculated,...
Abstract Most large galaxies host supermassive black holes in their nuclei and are subject to mergers, which can produce a hole binary (SMBHB), hence periodic signatures due orbital motion. We report unique radio flux density variations the blazar PKS 2131−021, strongly suggest an SMBHB with separation of ∼0.001–0.01 pc. Our 45.1 yr light curve shows two epochs strong sinusoidal variation same period phase within ≲2% ∼10%, respectively, straddling 20 when this was absent. simulated curves...
Abstract There is a growing concern about an impact of low-Earth-orbit (LEO) satellite constellations on ground-based astronomical observations, in particular, wide-field surveys the optical and infrared. The Zwicky Transient Facility (ZTF), thanks to large field view its camera, provides ideal setup study effects LEO megaconstellations—such as SpaceX’s Starlink—on surveys. Here, we analyze archival ZTF observations collected between 2019 November 2021 September find 5301 streaks that can be...
Abstract Two independent groups reported the discovery of an isolated dark stellar remnant in microlensing event OGLE-2011-BLG-0462 based on photometric ground-based observations coupled with astrometric measurements taken Hubble Space Telescope. These two analyses yielded discrepant mass measurements, first group reporting that lensing object is a black hole 7.1 ± 1.3 M ⊙ whereas other concluded was caused by either neutron star or low-mass (1.6–4.4 ). Here, we scrutinize available and data...
Abstract We report the discoveries of low-mass free-floating planet (FFP) candidates from analysis 2006–2014 MOA-II Galactic bulge survey data. In this data set, we found 6111 microlensing and identified a statistical sample consisting 3535 high-quality single-lens events with Einstein radius crossing times in range 0.057 < t E /days 757, including 13 that show clear finite-source effects angular radii 0.90 θ / μ as 332.54. Two 12 1 day have significant effects, one event, MOA-9y-5919, =...
We report discovery of the lowest mass ratio exoplanet to be found by microlensing method in light curve event OGLE 2016–BLG–1195. This planet revealed itself as a small deviation from single lens profile an examination survey data. The duration planetary signal is ∼2.5 h. measured its host star q = 4.2 ± 0.7 × 10−5. further estimate that system likely comprise cold ∼3 Earth ∼2 au wide orbit around 0.2 Solar at overall distance 7.1 kpc.
We present microlens parallax measurements for 21 (apparently) isolated lenses observed toward the Galactic bulge that were imaged simultaneously from Earth and Spitzer, which was ∼1 AU west of in projection. combine these with a kinematic model Galaxy to derive distance estimates each lens, error bars are small compared Sun's galactocentric distance. The ensemble therefore yields well-defined cumulative distribution lens distances. In principle, it is possible compare this against set...
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, distances these are measured indirectly and model-dependent. We constructed map three-dimensions based on positions thousands classical Cepheid variable stars. This shows structure our Galaxy's young stellar population, allows us to constrain warped shape Way's disk. A simple model star formation arms reproduces observed...