Astronomy

Extracting common signal components from the X-ray and optical light curves of GX 339-4: new view for anti-correlation

Simultaneous X-ray and optical observations of black hole X-ray binaries have shown that the light curves contain multiple correlated and anti-correlated variation components when the objects are in the hard state. In the case of the black hole X-ray …

Noise reduction for weak lensing mass mapping: An application of generative adversarial networks to Subaru Hyper Suprime-Cam first-year data

We propose a deep-learning approach based on generative adversarial networks (GANs) to reduce noise in weak lensing mass maps under realistic conditions. We apply image-to-image translation using conditional GANs to the mass map obtained from the …

First M87 Event Horizon Telescope Results. VII. Polarization of the Ring

In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3mm wavelength observations revealed a compact asymmetric ring-like source morphology. This …

First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon

Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotron radiation probes the structure of magnetic fields and the plasma …

Relationship between radar cross section and optical magnitude based on radar and optical simultaneous observations of faint meteors

Radar and optical simultaneous observations of meteors are important to understand the size distribution of the interplanetary dust. However, faint meteors detected by high power large aperture radar observations, which are typically as faint as 10 …

Feature selection for classification of blazars based on optical photometric and polarimetric time-series data

Blazars can be divided into two subtypes, flat spectrum radio quasars (FSRQs) and BL Lac objects, which have been distinguished phenomenologically by the strength of their optical emission lines, while their physical nature and relationship are still …

Search for Alignment of Disk Orientations in Nearby Star-forming Regions: Lupus, Taurus, Upper Scorpius, ρ Ophiuchi, and Orion

Spatial correlations among protoplanetary disk orientations carry unique information on physics of multiple-star formation processes. We select five nearby star-forming regions that comprise a number of protoplanetary disks with spatially resolved …

Super-resolution Imaging of the Protoplanetary Disk HD 142527 Using Sparse Modeling

With an emphasis on improving the fidelity even in super-resolution regimes, new imaging techniques have been intensively developed over the last several years, which may provide substantial improvements to the interferometric observation of …

An optical search for transients lasting a few seconds

Using a prototype of the Tomo-e Gozen wide-field CMOS mosaic camera, we acquire wide-field optical images at a cadence of 2 Hz and search them for transient sources of duration 1.5 to 11.5 seconds. Over the course of eight nights, our survey …

New Constraint on the Atmosphere of (50000) Quaoar from a Stellar Occultation

We report observations of a stellar occultation by the classical Kuiper Belt object (50000) Quaoar that occurred on 2019 June 28. A single-chord high-cadence (2Hz) photometry data set was obtained with the Tomo-e Gozen CMOS camera mounted on the 1.05 …