microlensing Archives

Simulated light curves for triple-lens systems where at least one planet lies in the resonant regime, as defined by the massratio-dependent boundaries (Equations 7) These configurations generally show strong central caustic perturbations and yield the highest detection efficiencies in our sample. For each case, the two smaller panels show the triple-lens magnification map and the map of the relative difference between the triple- and binary-lens models near the central caustic. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

Predictions Of The Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. V. Detection Rates of Multiplanetary Systems In High Magnification Microlensing Events

by Keith CowingDecember 27, 2025

The Nancy Grace Roman Space Telescope will expand the reach of gravitational microlensing surveys by increasing the number of events monitored and the precision of their light curves.

Peak emission wavelength of a Dyson Swarm as a function of swarm temperature, following Wien’s displacement law, λmax = b/TDS. The shaded regions indicate the approximate wavelength coverage of key infrared observatories: JWST/NIRCam (red band with star hatching, 0.6−5.0 µm ) JWST/MIRI (orange band with slanted hatching, 5.0−28.3 µm) and Roman/Euclid (NIR) (blue band with dotted hatching, 0.5−2.0 µm). For example, a swarm at TDS ∼ 300 K peaks near ∼ 10 µm, within JWST- MIRI’s sensitivity, whereas hotter swarms (TDS ≳ 1000 K) peak in the near-IR range of Euclid and Roman. -- astro-ph.IM

Astronomy & Telescopes, Biosignatures & Paleobiology, Imaging & Spectroscopy, Intelligence & Language, Press Release, SETI & Technosignatures

Microlensing Signatures Of Dyson Sphere-like Structures Around Primordial Black Holes As Technosignatures Of Extraterrestrial Advanced Civilizations

by Keith CowingDecember 11, 2025December 10, 2025

We investigate the microlensing detectability of extraterrestrial technosignatures originating from Dyson sphere – like structures, such as Dyson Swarms surrounding primordial black holes (PBHs).

A representative sample of nine historical events from Table 5. The top row shows nearby (< 4 kpc) events for which a combination of all three mass-distance relations (θE, πE, lens flux) give an unambiguously measured lens mass and distance. The yellow data with error bars shows the best fit result from image-constrained modeling, the blue contours give the posterior distribution (central 39%, 86%, 99%) from pyLIMASS. The middle row shows more distant events (> 4 kpc) for which the estimate of lens mass and distance is still relatively accurate but less precise. The bottom row shows problematic events for which there are degeneracies that remain (MB10328; Vandorou et al. 2025b), or the identification of the lens is dubious (MB11262; Terry et al. 2025b), or the significantly overlapping θE and πE relations result in large errors (OB141760; Rektsini et al. 2025).-- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. IV. Lens Mass and Distance Measurements

by Keith CowingOctober 20, 2025October 20, 2025

As part of the Galactic Bulge Time Domain Survey (GBTDS), the Nancy Grace Roman Galactic Exoplanet Survey (RGES) will use microlensing to discover cold outer planets and free-floating planets unbound […]

Color-magnitude diagram of the three events. The CMDs (black dots) of KMT-2022-BLG-0954 and MOA-2024-BLG-018 are constructed from the OGLE-III star catalog (Szymański et al. 2011) within a 2.5' radius centered on the event position, while the CMD of KMT-2024-BLG-0697 is built from KMTC field stars within a 2' × 2'′ square centered on the event position. The red asterisk marks the centroid of the red clump (RC), and the blue dot indicates the source position for the best-fit 2L1S solution. The green points represent the HST CMD from Holtzman et al. (1998), whose red clump centroid, (𝑉 − 𝐼, 𝐼)RC,𝐻𝑆𝑇 = (1.62, 15.15) (Bennett et al. 2008), has been matched to that of KMTC or OGLE-III. For KMT-2022-BLG-0954, the gold and magenta dots represent the primary and secondary sources of the 1L2S model, respectively. The blue line indicates the blue boundary of the bulge main-sequence stars, derived from stellar isochrones with [M/H] = −1.0 and age > 9 Gyr. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar, Status Report

A Comprehensive Analysis of Three Microlensing Planet Candidates with the Planet/Binary Degeneracy

by Keith CowingSeptember 28, 2025September 27, 2025

We present observations and analyses of three high-magnification microlensing events: KMT-2022-BLG-0954, KMT-2024-BLG-0697, and MOA-2024-BLG-018.

Physical parameters of the simulated events with and without detected moons. In each panel, the grey points show the events our simulation where a moon was not detected, i.e., these are the distributions of the physical parameters of the planets and moons we simulated. The stars show events where the moon was detected. The blue markers indicate the locations of the light curves shown in Figure 6 in these parameter spaces. Each panel shows (a) the planet/star mass ratio versus planet projected separation in units of the Einstein ring radius of the system. The lines indicate the boundaries of the resonant caustic region that we exclude from our sample; (b) the planet mass versus the planet semimajor axis; (c) moon/planet mass ratio versus the moon-planet separation in units of the Einstein ring radius of the planet; (d) moon mass versus semimajor axis of the moon in units of the Hill radius. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. III. Detectability of Giant Exomoons of Wide Separation Giant Planets

by Keith CowingSeptember 7, 2025September 7, 2025

Roman should be sensitive to lenses with mass down to ~ 0.02 M⊕, or roughly the mass of Ganymede. Thus the detection of moons with masses similar to the giant […]

Keck NIRC2-LGS images of the two events. North is up and East is to the left. The green and red boxes indicate the target and comparison stars, respectively. Insets show zoomed-in views of each star, including the original image and the residuals following PSF subtraction, which are shown on the identical flux scale to facilitate comparison. The gray dotted circles in the residual images show the predicted lens-source separation. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

KMT-2018-BLG-0029Lb and OGLE-2019-BLG-0960Lb: Mass Measurements for Two Super-Earth Microlensing Planets

by Keith CowingAugust 29, 2025August 29, 2025

KMT-2018-BLG-0029Lb and OGLE-2019-BLG-0960Lb were the lowest mass-ratio microlensing planets at the time of discovery. For both events, microlensing parallax measurements from the Spitzer Space Telescope implied lens systems that were […]

The magnification excess maps for planet-satellite configurations with log q = −1.5 and | log s| = 0.3. The color coding indicates fractional magnification differences between the 2L1S and 1L1S models. The maps with wide-separation (log s = 0.3) and close-separation (log s = −0.3) cases are displayed in the upper and lower panels, respectively. The left and right panels correspond to Earthmass and Neptune-class planets. The x-y coordinates denote the source positions in units of θE, with the positive x-axis aligned in the direction pointing from the planet (gold star) to the satellite (cyan star). Magenta circles indicate the source stars’ sizes (ρ = 0.33 for Earth-mass lenses and ρ = 0.08 for Neptune-class). Caustics are depicted in red, with the central caustic located near the planet and the satellite caustics positioned farther away. Each panel includes a lower-right inset offering a zoom-in view of the central caustics. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Detecting Exomoons In Free-Floating-Planet Events From Space-based Microlensing Surveys

by Keith CowingMay 30, 2025May 26, 2025

When a planet is ejected from its star-planet system due to dynamical interactions, its satellite may remain gravitationally bound to the planet.

Distribution of known exoplanet masses plotted vs. semi-major axis (left) and semimajor axis normalized to the location of the snow-line (right) at asnow = 2.7AU M/MSun (green dashed line). Planets found by the Doppler/RV method (black lines with upward error bars indicating the sin i uncertainty, where i refers to line-of-sight inclination), transits (blue squares), microlensing (red error bar crosses), direct detection, (magenta triangles) timing (green triangles) and transit timing variations (gold diamonds). Small cyan spots indicate Kepler planets and planet candidates without mass measurements. Black letters show the locations of our Solar System's planets. Microlensing discoveries. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Exoplanet Detection With Microlensing

by Keith CowingMay 20, 2025May 20, 2025

Microlensing is the method of exoplanet detection that discovers solar system analog exoplanets.

Earth-like Exoplanet - Grok via Astrobiology.com

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release

Astronomers Find Earth-like Exoplanets Are Common Across The Cosmos

by Keith CowingMay 9, 2025

Using the Korea Microlensing Telescope Network (KMTNet), an international team of researchers has discovered that super-Earth exoplanets are more common across the universe than previously thought, according to a new […]

Periods and mass ratios for planets detected using different methods. Data points show all exoplanets catalogued on 30 July 2023 (41) and are color-coded by detection method (see legend). The magenta star indicates OGLE-2016-BLG-0007Lb (error bars show 68% confidence intervals for this planet, but are omitted from all other planets). Colored images show six Solar System planets: Venus, Earth, Jupiter, Saturn, Uranus and Neptune. Filled magenta points are our collated sample of planets from the KMTNet microlensing survey (see text); empty magenta circles are other planets detected with the microlensing technique. The microlensing detections include planets with mass-ratios corresponding to super-Earths with Jupiter-like orbital periods. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Microlensing Events Indicate That Super-Earth Exoplanets Are Common In Jupiter-like Orbits

by Keith CowingMay 2, 2025

Exoplanets classified as super-Earths are commonly observed on short period orbits, close to their host stars, but their abundance on wider orbits is poorly constrained. Gravitational microlensing is sensitive to […]

microlensing

Predictions Of The Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. V. Detection Rates of Multiplanetary Systems In High Magnification Microlensing Events

Microlensing Signatures Of Dyson Sphere-like Structures Around Primordial Black Holes As Technosignatures Of Extraterrestrial Advanced Civilizations

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. IV. Lens Mass and Distance Measurements

A Comprehensive Analysis of Three Microlensing Planet Candidates with the Planet/Binary Degeneracy

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. III. Detectability of Giant Exomoons of Wide Separation Giant Planets

KMT-2018-BLG-0029Lb and OGLE-2019-BLG-0960Lb: Mass Measurements for Two Super-Earth Microlensing Planets

Detecting Exomoons In Free-Floating-Planet Events From Space-based Microlensing Surveys

Exoplanet Detection With Microlensing

Astronomers Find Earth-like Exoplanets Are Common Across The Cosmos

Microlensing Events Indicate That Super-Earth Exoplanets Are Common In Jupiter-like Orbits

Astrochemistry: Hubble and JWST Observe Star Formation in The Carina Nebula

Mapping the Historical Roots of Astrobiology: A Reference Publication Year Spectroscopy (RPYS) Analysis

The Agentic Observer Hackathon: Autonomous Decision-making in Simulated Astronomical Surveys

Tracking The Evolution of sub-Neptunes. I. Gyrochronology of Planet Hosting Stars

Tracking the Evolution of Sub-Neptunes. II. The Radius Valley on Gyrochronological Ages