Galaxies: Formation, Evolution, Phenomena

We study the early dynamical evolution of young dense star clusters by using Monte Carlo simulations for systems with up to N = 10 7 stars. Rapid mass segregation of massive main-sequence stars and the development of the Spitzer instability can drive these systems to core collapse in a small fraction of the initial ha…

• MEHMET ATAKAN GÜRKAN

The standard model of cosmology has provided a good phenomenological description of a wide range of observations both at astrophysical and cosmological scales for several decades. This concordance model is constructed by a universal cosmological constant and supported by a matter sector described by the standard model…

• AYŞE NİHAN KATIRCI

The standard model of cosmology has provided a good phenomenological description of a wide range of observations both at astrophysical and cosmological scales for several decades. This concordance model is constructed by a universal cosmological constant and supported by a matter sector described by the standard model…

• MEHMET DEMİRCİ

We present a new study of the collisional runaway scenario to form an intermediate-mass black hole (IMBH, MBH≳ 100 M⊙) at the centre of a young, compact stellar cluster. The first phase is the formation of a very dense central core of massive stars (M*≃ 30–120 M⊙) through mass segregation and gravothermal collapse. Pr…

• MEHMET ATAKAN GÜRKAN

Abstract We explore color-kinematic duality for tree-level AdS/CFT correlators in momentum space. We start by studying the bi-adjoint scalar in AdS at tree-level as an illustrative example. We follow this by investigating two forms of color-kinematic duality in Yang-Mills theory, the first for the integrated correlato…

• SONER ALBAYRAK

ABSTRACT We present an X-ray spectropolarimetric analysis of the bright Seyfert galaxy NGC 4151. The source has been observed with the Imaging X-ray Polarimetry Explorer (IXPE) for 700 ks, complemented with simultaneous XMM–Newton (50 ks) and NuSTAR (100 ks) pointings. A polarization degree Π = 4.9 ± 1.1 per cent and…

In this paper, we study two different models of dark energy based on the Chaplygin gas equation of state. The first model is the variable modified Chaplygin gas, while the second one is the extended Chaplygin gas. Both models are considered in the framework of higher order $$f(R)$$ modified gravity. We also consider t…

• EMRE ONUR KAHYA

We compute the one loop self-mass of a charged massless, minimally coupled scalar in a locally de Sitter background geometry. The computation is done in two different gauges: the noninvariant generalization of Feynman gauge which gives the simplest expression for the photon propagator and the de Sitter invariant gauge…

• EMRE ONUR KAHYA

We study the light deflection effect and the relativistic periastron and frame-dragging precessions for a rotating black hole localized on the brane in the Randall-Sundrum braneworld scenario. Focusing on a light ray, which passes through the field of the black hole in its equatorial plane, we first calculate the defl…

• ALİKRAM NUHBALAOĞLU

No abstract yet.

• EMRE DEMİR

We propose extended Chaplygin gas equation of state for which it recovers barotropic fluid with quadratic equation of state. We use numerical method to investigate the behavior of some cosmological parameters such as scale factor, Hubble expansion parameter, energy density, and deceleration parameter. We also discuss…

• EMRE ONUR KAHYA

Multiwavelength observations of Galactic black hole transients during outburst decay are instrumental for our understanding of the accretion geometry and the formation of outflows around black hole systems. H1743-322, a black hole transient observed intensely in X-rays and also covered in the radio band during its 200…

• EMRAH KALEMCİ