Related papers: Exploring accretion theory with X-ray binaries in …
Optical and X-ray observations are presented here of a newly reported X-ray transient system in the Small Magellanic Cloud. The data reveal many previously unknown X-ray detections of this system and clear evidence for a 49.995d binary…
We study low-mass binary X-ray sources involving stellar mass black holes within massive gravity. Regarding the accretion disk, we adopt the standard model for an optically thick, cool, and geometrically thin disk by Shakura-Sunyaev. For…
Circumbinary disks crucially affect the orbital and electromagnetic properties of binary systems across the universe, from stars in our galactic neighborhood to supermassive black hole binaries formed as the result of tumultuous galactic…
The baryonic fraction of galaxies is observed to vary with the mass of its dark matter (DM) halo. Low-mass galaxies have low baryonic fractions which increase to a maximum for masses near $10^{12}\ M_{\odot}$, and decreases thereafter with…
Accreting X-ray pulsars are among the best observed objects of X-ray astronomy with a rich data set of observational phenomena in the spectral and timing domain. While the general picture for these sources is well established, the detailed…
Formation models in which terrestrial bodies grow via the pairwise accretion of planetesimals have been reasonably successful at reproducing the general properties of the solar system, including small body populations. However, planetesimal…
We use hydrodynamic simulations to examine how the baryonic components of galaxies are assembled, focusing on the relative importance of mergers and smooth accretion in the formation of ~L_* systems. In our primary simulation, which models…
Supergiant X-ray Binaries (SgXB) host a compact object, often a neutron star (NS), orbiting an evolved O/B star. Mass transfer proceeds through the intense line-driven wind of the stellar donor, a fraction of which is captured by the…
We develop a model for supermassive black hole binaries (SMBHBs) accreting below their Eddington limit, focusing on systems where hot, advection-dominated flows become viable. We specifically explore the spectral appearance of…
Massive stars play a major role in the evolution of their host galaxies, and serve as important probes of the distant Universe. It has been established that the majority of massive stars reside in close binaries and will interact with their…
X-ray light curves of three X-ray pulsars, SMC X-1, LMC X-4 and Her X-1, folded with their respective super-orbital periods, are shown to be well reproduced by a model in which X-rays from a compact object towards us are periodically…
Thanks to IXPE , the X-ray spectro-polarimeter launched at the end of 2021, X-ray polarimetry has finally become an extraordinary tool in investigating the physics of accretion in low mass X-ray binaries. Similarly to what happened with…
The $\Lambda$CDM model of structure formation makes strong predictions on concentration and shape of DM (dark matter) halos, which are determined by mass accretion processes. Comparison between predicted shapes and observations provides a…
Galaxy cluster number count has been proven to be a powerful cosmological probe. However, cosmological constraints established with galaxy cluster number count are highly dependent on the calibration of the mass-observable relations. Thanks…
The stellar mass-luminosity relation is poorly constrained by observations for high mass stars. We describe our program to find eclipsing massive binaries in the Magellanic Clouds using photometry of regions rich in massive stars, and our…
We estimate the observed distribution of chirp masses of compact object binaries for the gravitational wave detectors. The stellar binary evolution is modeled using the {\em StarTrack} population synthesis code. The distribution of the…
In order to find an explanation for the radiative quiescence of supermassive black holes in the local Universe, for a sample of nearby galaxies the most accurate estimates are collected for the mass of a central black hole M_BH, the nuclear…
The HST/ACS Survey of Galactic globular clusters (GGCs) is a HST Treasury project aimed at obtaining high precision photometry in a large sample of globular clusters. The homogeneous photometric catalogs that has been obtained from these…
The end state of a coalescing binary of compact objects depends strongly on the final total mass M and angular momentum J. Since gravitational radiation emission causes a slow evolution of the binary system through quasi-circular orbits…
Recent RXTE and Chandra discoveries of low mass X-ray binaries with ultra-short orbital periods have initiated theoretical work on the origins of these peculiar systems. Using the StarTrack population synthesis code the formation and…