Related papers: JWST Spectroscopy of a Blue Binary Cold Classical …

In this manuscript, a 6.4yr optical quasi-periodic oscillations (QPOs) is detected in the quasar SDSS J075217.84+193542.2 (=\obj) at a redshift 0.117, of which 13.6yr-long light curve from CSS and ASAS-SN directly described by a sinusoidal…

The black hole candidate XTE J2012+381 underwent an outburst at the end of 2022. We analyzed 105 NICER observations and 2 NuSTAR observations of the source during the outburst. The NuSTAR observations of the $M \sim10M_\odot$ black hole…

We report detection of the binary companion to the millisecond pulsar J2302+4442 based on the deep observations performed with the Gran Telescopio Canarias. The observations revealed an optical source with $r'$ = 23.33$\pm$0.02 and…

We have used the multiobject mode of the Near-Infrared Spectrograph (NIRSpec) on board the James Webb Space Telescope (JWST) to obtain low-resolution 1-5um spectra of 22 brown dwarf candidates in the Orion Nebula Cluster, which were…

We report on the properties of eclipsing binaries from the Kepler mission with a newly developed photometric modeling code, which uses the light curve, spectral energy distribution of each binary, and stellar evolution models to infer…

We present the discovery of a companion to the Y-dwarf, CWISEP J193518.59-154620.3, the second Y-Y dwarf binary detected to date. Y-dwarfs are the coldest known free-floating objects ($<$ 500 K) and on average represent the lowest mass…

We are in a golden era observing Young Stellar Objects (YSOs), protoplanetary disks, and substellar objects, crucial for understanding their formation and evolution. This Ph.D. thesis explores two binary systems. Firstly, we study an…

We report the discovery of peculiar X-ray spectral variability in the binary radio millisecond pulsar PSR J0024--7204W in the globular cluster 47 Tucanae. The observed emission consists of a dominant non-thermal component, which is eclipsed…

We present Keck/ESI long-slit spectroscopy of SBS 1421+511, a system consisting of a quasar at z = 0.276 and an extended source 3" northern to the quasar. The quasar shows a blue-skewed profile of Balmer broad emission lines, which can be…

We report our multi-band infrared (IR) imaging of the transitional millisecond pulsar system J1023+0038, a rare pulsar binary known to have an accretion disk in 2000--2001. The observations were carried out with ground-based and space…

We present UV and optical spectropolarimetry of two highly polarized IRAS-selected QSOs, IRAS 13349+2438 and the BALQSO IRAS 14026+4341. The polarization in both objects rises rapidly toward the blue, peaks near 3000 A in the rest frame and…

Our discovery of 1SWASP J093010.78+533859.5 as a probable doubly eclipsing quadruple system containing a contact binary with P~0.23 d and a detached binary with P~1.31 d was announced in 2013. Subsequently Koo et al. confirmed the detached…

We present the first joint NuSTAR and NICER observations of the ultra-compact X-ray binary (UCXB) 4U 0614+091. This source shows quasi-periodic flux variations on the timescale of ~days. We use reflection modeling techniques to study…

Spitzer observations of the neutron star (ultra-compact) X-ray binary (XRB) 4U 0614+091 with the Infrared Array Camera reveal emission of non-thermal origin in the range 3.5-8 um. The mid-infrared spectrum is well fit by a power law with…

The eclipsing binary T-Cyg1-12664 was observed both spectroscopically and photometrically. Radial velocities of both components and ground-based VRI light curves were obtained. The Kepler's R-data and radial velocities for the system were…

The binary emission-line system, particularly the binary broad-line emission system, is considered the most effective indicator of the black hole binary. A plausible example of such a system, SDSS J153636.22+044127.0, was reported as the…

Recent observations (Burnes et al 2002,Veillet et al 2002, Margot et al 2002a) have revealed an unexpectedly high binary fraction among the Trans-Neptunian Objects (TNOs) that populate the Kuiper Belt. The TNO binaries are strikingly…

Mrk 231 is a nearby quasar with an unusually red near-UV-to-optical continuum, generally explained as heavy reddening by dust (e.g., Leighly et al. 2014). Yan et al. 2015 proposed that Mrk~231 is a milli-parsec black-hole binary with little…

We report our analyses of the multi-epoch (2015-2017) ALMA archival data of the Class II binary system XZ Tau at Bands 3, 4 and 6. The millimeter dust continuum images show compact, unresolved (r <~ 15 au) circumstellar disks (CSDs) around…

We conducted a two-night photometric survey of small Kuiper Belt objects (KBOs) near opposition using the wide-field Hyper Suprime-Cam instrument on the 8.2 m Subaru Telescope. The survey covered about 90 deg^2 of sky, with each field…