Modelling the energy dependencies of high-frequency QPO in black hole X-ray binaries

We model energy dependencies of the quasi periodic oscillations (QPO) in the model of disc epicyclic motions, with X-ray modulation caused by varying relativistic effects. The model was proposed to explain the high frequency QPO observed in X-ray binaries. We consider two specific scenarios for the geometry of accretion flow and spectral formation. Firstly, a standard cold accretion disc with an active X-ray emitting corona is assumed to oscillate. Secondly, only a hot X-ray emitting accretion flow oscillates, while the cold disc is absent at the QPO radius. We find that the QPO spectra are generally similar to the spectrum of radiation emitted at the QPO radius, and they are broadened by the relativistic effects. In particular, the QPO spectrum contains the disc component in the oscillating disc with a corona scenario. We also review the available data on energy dependencies of high frequency QPO, and we point out that they appear to lack the disc component in their energy spectra. This would suggest the hot flow geometry in the spectral states when high frequency QPO are observed.Comment: 8 pages, accepted for publication in MNRA

Energy spectra of X-ray quasi-periodic oscillations in accreting black hole binaries

We investigate the energy dependencies of X-ray quasi-periodic oscillations in black hole X-ray binaries. We analyze RXTE data on both the low- and high-frequency QPO. We construct the low-f QPO energy spectra, and demonstrate that they do not contain the thermal disk component, even though the latter is present in the time averaged spectra. The disk thus does not seem to participate in the oscillations. Moreover the QPO spectra are harder than the time averaged spectra when the latter are soft, which can be modeled as a result of modulations occurring in the hot plasma. The QPO spectra are softer than the time averaged spectra when the latter are hard. The absence of the disk component in the QPO spectra is true also for the high-frequency (hecto-Hz) QPO observed in black hole binaries. We compute the QPO spectra expected from the model of disk resonances.Comment: 4 pages, Proc. of IAU Symposium 238, "Black Holes from Stars to Galaxies - across the range of masses", Prague, Aug 200

X-ray observations of the hot phase in Sgr~A*

We analyze 134 ks Chandra ACIS-I observations of the Galactic Centre (GC) performed in July 2011. The X-ray image with the field of view $17' \times 17'$ contains the hot plasma surrounding the Sgr~A*. The obtained surface brightness map allow us to fit Bondi hot accretion flow to the innermost hot plasma around the GC. We have fitted spectra from region up to $5"$ from Sgr~A* using a thermal bremsstrahlung model and four Gaussian profiles responsible for K$_{\alpha}$ emission lines of Fe, S, Ar, and Ca. The X-ray surface brightness profile up to $3"$ from Sgr~A* found in our data image, was successfully fitted with the dynamical model of Bondi spherical accretion. By modelling the surface brightness profile, we derived the temperature and number density profiles in the vicinity of the black hole. The best fitted model of spherical Bondi accretion shows that this type of flow works only up to $3"$ and implies outer plasma density and temperature to be: $n_{\rm e}^{\rm out}=18.3 \pm {0.1}$ cm$^{-3}$ and $T_{\rm e}^{\rm out}= 3.5 \pm {0.3}$ keV respectively. We show that the Bondi flow can reproduce observed surface brightness profile up to $3"$ from Sgr~A* in the Galactic Center. This result strongly suggests the position of stagnation radius in the complicated dynamics around GC. The Faraday rotation computed from our model towards the pulsar PSR J1745-2900 near the GC agrees with the observed one, recently reported.Comment: 10 pages, 7 figures, accepted for publication in A&

Synthetic catalog of black holes in the Milky Way

We present an open-access database which includes a synthetic catalog of black holes in the Milky Way. To calculate evolution of single and binary stars we used updated population synthesis code StarTrack. We applied a new model of star formation history and chemical evolution of Galactic disk, bulge and halo synthesized from observational and theoretical data. We find that at the current moment Milky Way (disk+bulge+halo) contains about 1.2 x 10^8 single black holes with average mass of about 14 Msun and 9.3 x 10^6 BHs in binary systems with average mass of 19 Msun. We present basic statistical properties of BH populations such as distributions of single and binary BH masses, velocities, orbital parameters or numbers of BH binary systems in different evolutionary configurations. We find that the most massive BHs are formed in mergers of binary systems, such as BH-MS, BH+He, BH-BH. The metallicity of stellar population has a significant impact on the final BH mass due to the stellar winds. Therefore the most massive single BH in our simulation, 113 Msun, originates from a merger of a helium star and a black hole in a low metallicity stellar environment in Galactic halo. The most massive BH in binary system is 60 Msun and was also formed in Galactic halo. We constrain that only 0.006% of total Galactic halo mass (including dark matter) could be hidden in the form of stellar origin BHs which are not detectable by current observational surveys. Galactic binary BHs are minority (10% of all Galactic BHs) and most of them are in BH-BH systems. The current Galactic merger rates for two considered common envelope models which are: 3-81 Myr^-1 for BH-BH, 1-9 Myr^-1, for BH-NS and 14-59 Myr^-1 for NS-NS systems. Data files are available at https://bhc.syntheticuniverse.org/.Comment: 21 pages, A&A accepted, data from catalog available onlin

effects of in ovo injection of prebiotics and synbiotics on the productive performance and microstructural features of the superficial pectoral muscle in broiler chickens

ABSTRACT The aim of the study was to compare the effects of 2 prebiotics and 2 synbiotics injected in ovo on productivity parameters, quality, and microstructure of the superficial pectoral muscle in 35-day-old broiler chickens. On day 12 of incubation, 9,000 eggs Ross 308 were randomly divided into 5 experimental groups treated with different bioactives in ovo injected: C, control with physiological saline; PI, with 1.760 mg inulin; PB, with 0.528 mg of commercial prebiotic Bi2 tos; SI, with 1.760 mg inulin and 1,000 CFU Lactococcus lactis spp. lactis IBB SL1; SB, with 0.528 mg Bi2 tos and 1,000 CFU Lactococcus lactis spp. cremoris IBB SC1. The synbiotic solution contained 20 μl bacterial suspension and 180 μl prebiotic solution. For productive parameters and further tests ten male birds for each experimental group were used. The birds were slaughtered on day 35 of age. At slaughter, samples of the left pectoral muscles were taken and preserved by freezing in liquid nitrogen. The pH and color of the meat were evaluated at 45 min and 24 h post-mortem. Water holding capacity (WHC) was measured and expressed as the percentage of free water in meat. Microscopic specimens were analysed using MultiScan software for the measurement of the percentage of oxidative and glycolytic fibres and mean diameter of the muscle fibres. In ovo injection of prebiotics Bi2 tos had a positive effect on body weight. In prebiotic group (PI) a negative impact on hatchability was observed. Prebiotics and synbiotics had no influence on the yield of the carcass and pectoral muscle. Bioactive compounds had a significant effect on the quality of meat parameters such as: pH 24 h (PI and PB group), L* 45' (SI and SB group), and WHC (groups PB, SI, and SB). The analysis of the enzymatic profile showed a significant increase in the percentage of glycolytic fibres in the pectoral muscle from chicken treated with a synbiotic with the addition of inulin (group SI)

Analysis of the course and treatment of toxocariasis in children—a long-term observation

Toxocariasis is a helminthozoonotic disease caused by ascarid larvae of Toxocara genus: Toxocara canis and Toxocara cati. In the reported study, the clinical course of toxocariasis and administered therapy were evaluated in 103 children. The majority of the children (68.9%) were from the rural environment, with a prevalence of boys (62.1%). At diagnosis of infection, 36 (35%) children reported recurrent abdominal pain, 19 (18.4%) headache, 6 (5.8%) loss of appetite, 2 subfebrile conditions, and 2 arthralgia, Moreover, 23 (22.3%) children demonstrated symptoms of atopic diseases; in 30 (29.1%) children, moderate enlargement of lymphatic nodes was noted. In five children (4.9%), ophthalmic examination revealed unilateral changes in the eye: in two cases retinitis; in one case fibrotic lesions in the vitreous body, complicated 1 year from diagnosis by retinal detachment; and in other children parafoveal lesions and cataract. Only two children with ocular changes at diagnosis reported visual disorders. In 64.3% of children, eosinophilia was observed. A covert form of the disease was diagnosed in 95.1% of the children and an ocular form in 4.9%. In all the children, antiparasitic treatment was implemented, repeated several times in some of them. After therapy, the mean titer of specific antibodies, the number of children with abdominal pains and enlarged lymphatic nodes were decreased, while headaches maintained at unchanged levels. In approximately one fourth of the children with negative results of antibodies after the therapy, the symptoms of the disease were still reported. Evaluation of the efficacy of treatment is not easy due to non-characteristic symptoms and low kinetics of specific anti Toxocara IgG decrease; however, high IgG titers suggest non-effective treatment of concomitant infection requiring subsequent therapy. Due to risk of ocular form, which may develop in any stage of the disease, irrespectively of specific antibodies concentrations, it seems justified to implement antiparasitic treatment in all children infected with T. canis

The extremely X-ray luminous radio-loud quasar CFHQS J142952+544717 at z=6.18z=6.18 under Chandra high-angular resolution lens

We present the first X-ray observation at sub-arcsecond resolution of the high-redshift ($z=6.18$) radio-loud quasar CFHQS J142952+544717 (J1429). The ~100 net-count 0.3-7 keV spectrum obtained from $\sim 30$ ksec Chandra exposure is best fit by a single power-law model with a photon index $\Gamma=2.0\pm0.2$ and no indication of an intrinsic absorber, implying a 3.6-72 keV rest-frame luminosity $L_{\rm X}=(2.3^{+0.6}_{-0.5})\times10^{46}$ erg s$^{-1}$. We identify a second X-ray source at 30 arcsec, distance from J1429 position, with a soft ($\Gamma\simeq 2.8$) and absorbed (equivalent hydrogen column density $N_{\rm H} <13.4\times 10^{20}$ cm$^{-2}$) spectrum, which likely contaminated J1429 spectra obtained in lower angular resolution observations. Based on the analysis of the Chandra image, the bulk of the X-ray luminosity is produced within the central $\sim 3$ kpc region, either by the disk/corona system, or by a moderately aligned jet. In this context, we discuss the source properties in comparison with samples of low- and high-redshift quasars. We find indication of a possible excess of counts over the expectations for a point-like source in a 0.5 arcsec-1.5 arcsec ($\sim 3-8$ kpc) annular region. The corresponding X-ray luminosity at J1429 redshift is $4\times 10^{45}$ erg s$^{-1}$. If confirmed, this emission could be related to either a large-scale X-ray jet, or a separate X-ray source.Comment: 9 pages, 4 figures, accepted for publication in MNRA