Related papers: A New Window for Studying Intermediate Polars and …

We present a photometric study of the newly discovered eclipsing IP $J183221.56-162724.25$ (in short $J1832$) with an orbital period of $8.87hr$. The system features a box-like deep eclipse with a full width at 50% depth of $1970\pm2s$ and…

We present follow-up photometric observations and time-series analysis of a nova-like, SW Sextans-type, cataclysmic variable (CV) candidate, LAMOST J204305.95+341340.6 (here after J2043+3413), with Gaia G-band magnitude of 15.30 and a…

[Abridged] We report Warm Spitzer full-orbit phase observations of WASP-12b at 3.6 and 4.5 micron. We are able to measure the transit depths, eclipse depths, thermal and ellipsoidal phase variations at both wavelengths. The large amplitude…

Using large number of Rossi X-ray Time Explorer observations of Sco X-1 we present a detailed investigation of the transition layer (TL) and the relativistic precession (RP) models. These models predict the existence of the invariant…

We present photometric time series data spanning 2018-2024 that show the effects of temporal dynamics in the binary system KH 15D, a member of the NGC 2264 star forming region. This source exhibits complex eclipsing behavior due to a…

EE Cep is a unique system in which a Be star is eclipsed by a dark dusty disk, making this star similar to the famous epsilon Aur in many respects. The depth and the duration of the EE Cep eclipses change to a large extent. The last two…

Recent observations of Type II supernovae (SNe) have brought a challenge in our understanding on the final evolutionary stage of massive stars. The early-time spectra and light curves of Type II SNe suggest that a majority of them have…

The low mass X-ray binary (LMXB) associated with the M31 globular cluster Bo 158 is known to exhibit intensity dips on a ~2.78 hr period. This is due to obscuration of the X-ray source on the orbital period by material on the outer edge of…

Episodic accretion has been proposed as a solution to the long-standing luminosity problem in star formation; however, the process remains poorly understood. We present observations of line emission from N2H+ and CO isotopologues using the…

Dipping neutron star low-mass X-ray binaries (NS LMXBs) are systems that exhibit periodic drops in their X-ray light curves. These are believed to be caused by material at the impact point of the gas stream onto the accretion disk, the…

A star crossing the tidal radius of a supermassive black hole will be spectacularly ripped apart with an accompanying burst of radiation. A few tens of such tidal disruption events (TDEs) have now been identified in the optical wavelengths,…

Misaligned accretion disks surrounding rotating compact objects experience a torque due to the Lense-Thirring effect, which leads to precession of the inner disk. It has been suggested that this effect could be responsible for some low…

We study the evolution of the broad, double-peaked Halpha emission-line profile of the LINER/Seyfert 1 nucleus of NGC 1097, using 24 spectra obtained over a time span of 11 yrs - from 1991 Nov. through 2002 Oct. While in the first 5 yrs the…

Stellar-mass black hole binary systems in the luminous X-ray states show a strong quasi-periodic oscillation (QPO) in their Comptonised emission. The frequency of this feature correlates with the ratio of a disc to Comptonised emission…

We report here CCD $I$-band time-series photometry of a young (2$-$5 Myr) cluster NGC 2282 to identify and understand the variability of pre-main-sequence (PMS) stars. The $I$-band photometry, down to $\sim$ 20.5 mag, enables us to probe…

We investigate the time evolution of luminous accretion disks around black holes, conducting the two-dimensional radiation-hydrodynamic simulations. We adopt the alpha prescription for the viscosity. The radial-azimuthal component of…

We present multi-epoch deep ($\sim$20 mag) $I_{c}$~band photometric monitoring of the Sh 2-170 star-forming region to understand the variability properties of pre-main-sequence (PMS) stars. We report identification of 47 periodic and 24…

Geometrically thick disks may form after tidal disruption events, and rapid accretion may lead to short flares followed by long-term, lower-level emission. Using a novel accretion disk code which relies primarily on global conservation laws…

Power spectra (PS) of high-resolution images of M51 (NGC 5194) taken with the Hubble Space Telescope and the James Webb Space Telescope have been examined for evidence of disk thickness in the form of a change in slope between large scales,…

Optically thin two-temperature accretion flows may be thermally and viscously stable, but acoustically unstable. Here we propose that the O-mode instability of a cooling-dominated optically thin two-temperature inner disk may explain the…