We studied the dependence of selected structural and kinematic properties of early-type galaxies (ETGs) on their environments. The selected sample, extracted from the SDSS-DR17 MaNGA survey, consists of 946 ETGs in clusters (cETGs) and 288 isolated ETGs (iETGs) within a spectroscopic redshift z≤ 0.15 . We investigated the distribution of these galaxies in the Fundamental Plane (FP), Kormendy Relation (KR), Faber-Jackson Relation (FJR) and the Mass-Size Relation (MSR). We found that massive galaxies, whose stellar masses M_*> 10^11M_⊙ , are predominantly elliptical ( >65% ). The analysis of the four scaling relations showed that the effect of the host environment is negligible for massive ( M_*>10^11.5M_⊙ ) ETGs, most likely because of their passive evolution through dry mergers and/or stellar aging. On the other hand, low-mass ETGs are influenced by their environment, where iETGs with M_*<10^10M_⊙ and velocity dispersion σ _0≤ 100 km/sec are 25% more luminous and 11.5% larger than cETGs. Low-mass cETGs may have suffered processes that removed their gas content and hence quenched star formation while low-mass iETGs may have experienced a recent wet merger that triggered star formation and led to their, currently, observed low mass-to-light ratio. However, further spectral analysis is needed to confirm these findings.

We present a comprehensive analysis of barred galaxies within two distinct samples: isolated single galaxies (SIG) and isolated galaxy pairs (SIP), drawn from the SDSS-based catalog of isolated galaxies and the catalog of isolated galaxy pair limited to M <= -18.5, respectively. Our primary aim is to investigate the influence of tidal effects on the bar fraction (f bar ) across various galaxy systems. Barred galaxies are identified through automated ellipse fitting analysis supplemented by visual inspection of r-band imaging. A strong correlation between f bar and both galaxy morphological type and star formation rate has been revealed. Although, barred galaxies represent a nearly equal percentage of 52% in SIG and 51% in SIP, we found a little evidence for the tidal dependence of bar formation where a notable increase in the f bar is observed among galaxies characterized by larger projected separation and higher radial velocity difference between the pair members. In SIGs, we observe a prevalent increasing trend of f bar with galaxy mass, contrasting the observed decrease in f bar with increasing galaxy mass in SIPs. This discrepancy is consistent with typical trends of weaker bars, suggesting that tidal effect may attenuate the strength of bar structures within galaxy pairs.

AbstractIn this paper, we re-estimate the astrometric and photometric parameters of the young open star cluster King 18 based on Gaia Data Release 3 (DR3), Two Micron All-sky Survey (2MASS) and VRI CCD observations using the f/4.9 Newtonian focus of 74-inch telescope at Kottamia Astronomical Observatory (KAO) in Egypt. King 18 is a poorly studied open star cluster, for which new results are found in the current study. In order to estimate the membership and determine all the astrophysical parameters of the cluster, we have used data from Gaia DR3 and KAO. The center, cluster radius, radial density distribution, color-magnitude diagrams, distance, age, and reddening of King 18 are calculated. Also, the luminosity and mass functions, the total mass and the relaxation time of the cluster are estimated. The slope value of the mass function ($$\alpha $$ α ) of King 18 is found to be 2.27± 0.17, which is comparable with Salpeter value. Our estimates for the average cluster age and the relaxation time are 224 ± 6.3 and 28.92 Myrs, respectively. This indicates that King 18 is dynamically stable and a relaxed cluster. The cluster distance modulus from Gaia, 2Mass and VRI observations has been determined to be 12.380 ± 1.320, 12.320 ± 0.107 and 12.280 ± 0.290 mag respectively, which corresponds to distances of 2992.26, 2910.72 and 2857.59 pc, respectively. These results are in good agreement within the error. Moreover the color excesses E(V–I), E(J–$$\hbox {K}_s$$ K s ) and E($$\hbox {G}_{{BP}}$$ G BP –$$\hbox {G}_{{RP}}$$ G RP ) are 0.850 ± 0.087, 0.380 ± 0.091 and 0.980 ± 0.130 respectively. Finally, the proper motions ($$\mu _{\alpha }$$ μ α cos$$\delta $$ δ , $$\mu _{\delta }$$ μ δ ), and parallaxes ($$\varpi $$ ϖ ) are $$-2.603 \pm 0.018$$ - 2.603 ± 0.018 , $$-2.106 \pm 0.013$$ - 2.106 ± 0.013 and 0.324 ± 0.040, respectively.

The high mass X-ray binary system 4U 0114+65 was observed by Nustar in October 2019, and by XMM-Newton in August 2015. Here we performed spectral and timing analysis of the Nustar observation, and carry out timing analysis on the XMM-Newton data. We measured the spin period of the neutron star from both observations and found a spin-up rate $\dot{p} = 1.54 \pm 0.38 \times 10^{-6} s s^{-1}$. During the Nustar observation two flares occured, one occured shortly after the start of the observation and the other near the end separated by a long period of low/quiescent- state. The large and sudden flares mostly resulted from accretion of Corotating Interaction Region (CIR) material. A common spectral model to HMXBs, powerlaw with high energy cutoff and absorption at low energy, gave a good fit to both flaring and quiescent states. A flourescent iron line was not required in fitting any of the states. On the other hand, very tentative evidence of Cyclotron Resonant Scattering Feature (CRSF) at $\sim$ 17 keV was found during fitting using cyclabs model, however fitting improvement was not significant enough to confirm its detection, plus a very narrow width (< 1 keV) was obtained for the line and its first harmonic. Visual inspection of the spectra showed a deficiency of emission near the expected first and second harmonic. Another important feature visually noticed in the spectra is the presence of hard tail above 50 keV. This could be explained by the shocked material bounding the CIR.

Abstract The r-band of the Sloan Digital Sky Survey (SDSS) for 17,924 brightest cluster galaxies (BCGs) in clusters and groups within 0.02 ⩽ z ⩽ 0.20 are used to study possible environmental relations affecting the nature of these galaxies. We find a correlation between BCGs physical properties (the effective radius (Re ), absolute magnitude and central velocity dispersion (σ 0)) and their host groups and clusters velocity dispersion (σcl ). This type of relations suggests that the most massive groups or clusters host larger central galaxies. On the other hand, the σ 0/σcl ratio as a function of σcl is consistent with [10].

IL28B gene polymorphisms are associated with the response to antiviral therapy in hepatitis C patients in the non-transplant setting. To determine the prevalence and impact on clinical outcomes of donor and recipient IL28B genotypes among liver transplant recipients receiving directly acting antiviral therapy compared to those of HCV non-transplant patients. This study included 60 patients divided into 2 groups: group 1 included 30 patients subjected to living donor liver transplantation and group 2 included 30 patients of HCV infection. Each group was subdivided into group A and group B according to the regimen of directly acting antiviral therapy (sofosbuvir-ledibasvir, sofosbuvir-daclatasvir). Liver transplantation was done between January 2016 and April 2018. Genotyping of the polymorphism was performed on DNA collected from all donors and recipients in group 1 before and after liver transplantation and also collected from all patients of group 2. Sustained virological response was found in 28 patients in group 1 (transplanted group) and 29 patients in group 2 (non-transplanted group) with no significant difference. No significant difference also was found in both groups according to the type of regimen. Also the type of genotype CC, CT and TT of IL28B in donors and recipients were not significantly associated or affecting the results of SVR in both groups of patients. Our results support no role of recipient IL28B genotype in the response to directly acting antiviral drugs for hepatitis C recurrence. Interestingly, donor genotype seems not to influence the response pattern in recipients who have different IL28B genotype.

This work aims to investigate the fundamental plane, the Kormendy, the Faber-Jackson, and the size-luminosity relations for two galaxy samples (brightest cluster galaxies (BCGs) and isolated elliptical galaxies (IEs)) in different environments. These relations are investigated in different wavelength bands, griz, of the Sloan Digital Sky Survey (SDSS). We constructed a sample of 2002 BCGs from the redMaPPer clusters catalog with spectroscopic redshifts in the range ($0.076 \leqslant \textit{z} \leqslant 0.394$). The sample of IEs consists of 550 objects and is extracted from the catalog of isolated galaxies (SDSS-based Isolated Galaxies, SIG) with spectroscopic redshifts range ($0.01 \leqslant \textit{z} \leqslant 0.08$). In general, we found that slopes of all studied scaling relations are waveband dependent except for the Faber-Jackson relation. The fundamental plane (FP) for both samples steepens as one moves from shorter to longer wavelengths. We found that BCGs lie on a different FP from that of IEs. In average the coefficient a of BCGs is larger than that of IEs by about 5$\sigma $, while the coefficient b is larger by about 11$\sigma $. By studying the Kormendy relation (KR), we found that its slope varies through the waveband for both samples. Also, the slope of BCGs is smaller than that of IEs by about 7$\sigma $, while the intercept is smaller by about 12$\sigma $. We also examined the Faber-Jackson (FJ) relation and found that its slope is similar for all wavebands for both samples. BCGs defines a steeper FJ relation than IEs such that $\mbox{L} \varpropto \sigma ^{6.25}$ for BCGs and $\mbox{L} \varpropto \sigma ^{2.63}$ for IEs. We also studied the size-luminosity relation and found that its slope is decreasing slightly with waveband for both samples. We also found that BCGs define a steeper size-luminosity relation than IEs, in average the slope of BCGs is greater than that of IEs by $\sim 7\sigma $.

A sample of edge-on (or nearly edge-on) spiral and lenticular galaxies is selected to study the warp phenomenon in their disks. This sample contains 36 disk galaxies selected from Watanabe’s catalogue (Watanabe, 1983). We investigate the existence of physical relations between photometric and spectroscopic parameters and the warp degree of galaxies.

The study of Early-Type Galaxies (ETGs) in different environments is a strong tool to understand their star formation history and their evolution. The Fundamental Plane (FP) of ETGs has been studied in different environments in the nearby universe such as in groups, clusters and the field. We found that our sample of ETGs in different environments shows a good agreement with the FP of Coma cluster, except for a scatter of some galaxies. A major part of the scatter in the FP is due to variations in mass to light ratio as a result of metallicity or age trends in the stellar populations and structural or dynamical properties of galaxies. We noticed that the most deviant galaxies from the FP show many fine structures as tidal tails, shells, dust and a kinematically distinct core which indicates a past merger involving at least one gas-rich progenitor.