118308331
A COMPARISON OF HARD X-RAY PHOTON INDICES AND IRON Kα EMISSION LINES IN X-RAY LUMINOUS NARROW- AND BROAD-LINE SEYFERT 1 GALAXIES
We use publicly available XMM-Newton data to systematically compare the hard X-ray photon indices, Γ2-10 keV , and the iron Kα emission lines of narrow- and broad-line Seyfert 1 (NLS1 and BLS1) galaxies. We compile a flux-limited (f 2-10 keV ≥ 1 × 10–12 erg s–1 cm–2) sample including 114 radio-quiet objects, with the 2-10 keV luminosity ranging from 1041 to 1045 erg s–1. Our main results are: (1) NLS1s and BLS1s show similar luminosity distributions; (2) the weighted means of Γ2-10 keV of NLS1s, BLS1s, and the total sample are 2.04 ± 0.04, 1.74 ± 0.02, and 1.84 ± 0.02, respectively; a significant anti-correlation between Γ2-10 keV and FWHMHβ suggests that Γ2-10 keV > 2.0 may be taken to indicate the X-ray luminous NLS1 type; (3) the 6.4 keV narrow iron Kα lines from NLS1s are generally weaker than that from BLS1s; this would indicate a smaller covering factor of the dusty tori in NLS1s if the line emission originates from the inner boundary region of the dusty torus in an active galactic nucleus; and (4) all the broadened iron Kα lines with intrinsic width σ>0.5 keV correspond to FWHMHβ ≤4000 km s–1.
51813822
Ionization structure and Fe K$\alpha$ energy for irradiated accretion disks
We study the radial ionization structure at the surface of an X-ray illuminated accretion disk. We plot the expected iron K$\alpha$ line energy as a function of the Eddington ratio and of the distance of the emitting matter from the central source, for a non-rotating and a maximally-rotating black hole. We compare the predicted disk line energies with those measured in an archival sample of active galactic nuclei observed with {\it Chandra}, {\it XMM-Newton} and {\it Suzaku}, and discuss whether the line energies are consistent with the radial distances inferred from reverberation studies. We also suggest using rapidly-variable iron K$\alpha$ lines to estimate the viscosity parameter of an accretion disk. There is a forbidden region in the line energy versus Eddington ratio plane, at low Eddington ratios, where an accretion disk cannot produce highly-ionized iron K$\alpha$ lines. If such emission is observed in low-Eddington-ratio sources, it is either coming from a highly-ionized outflow, or is a blue-shifted component from fast-moving neutral matter.
118669017
HARD X-RAY PHOTON INDEX AS AN INDICATOR OF BOLOMETRIC CORRECTION IN ACTIVE GALACTIC NUCLEI
We propose the rest-frame 2-10 keV photon index, {Gamma}{sub 2-10keV}, acting as an indicator of the bolometric correction, L {sub bol}/L {sub 2-10keV} (where L {sub bol} is the bolometric luminosity and L {sub 2-10keV} is the rest-frame 2-10 keV luminosity), in radio-quiet active galactic nuclei (AGNs). Correlations between {Gamma}{sub 2-10keV} and both bolometric correction and Eddington ratio are presented, based on simultaneous X-ray, UV, and optical observations of reverberation-mapped AGNs. These correlations can be compared with those for high-redshift AGNs to check for any evolutionary effect. Assuming no evolutionary effect in AGNs' spectral properties, together with the independent estimates of L {sub 2-10keV}, the bolometric correction, Eddington ratio, and black hole (BH) mass can all be estimated from these correlations for high-redshift AGNs, with the mean uncertainty of a factor of 2-3. If there are independent estimates of BH masses, {Gamma}{sub 2-10keV} for high-redshift AGNs can be used to determine their true L {sub bol} and L {sub 2-10keV}, and in conjunction with the redshift can be potentially used to place constraints on cosmology by comparison with the rest-frame 2-10 keV flux. We find that the true L {sub 2-10keV} estimated from {Gamma}{sub 2-10keV} for the brightest Type Imore » AGNs with z < 1 in the Lockman Hole is generally in agreement with the observed L {sub 2-10keV}. However, there are still many uncertainties, such as the accurate determination of the intrinsic {Gamma}{sub 2-10keV} for distant AGNs and the large uncertainty in the luminosities obtained, which call for significant further study before 'AGN cosmology' can be considered a viable technique.« less
119274239
HST and LAMOST discover a dual active galactic nucleus in J0038+4128
We report the discovery of a kiloparsec-scale dual active galactic nucleus (AGN) in J0038+4128. From the Hubble Space Telescope (HST) Wide Field Planetary Camera (WFPC2) images, we find two optical nuclei with a projection separation of 4.7 kpc (3.44 arcsec). The southern component (J0038+4128S) is spectroscopically observed with the HST Goddard High Resolution Spectrograph in the UV range and is found to be a Seyfert 1 galaxy with a broad Ly alpha emission line. The northern component (J0038+4128N) is spectroscopically observed during the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (also named the Guoshoujing Telescope) pilot survey in the optical range. The observed line ratios as well as the consistency of redshift of the nucleus emission lines and the host galaxy's absorption lines indicate that J0038+4128N is a Seyfert 2 galaxy with narrow lines only. These results thus confirm that J0038+4128 is a Seyfert 1-Seyfert 2 AGN pair. The HST WFPC2 F336W/U-band image of J0038+4128 also reveals for the first time for a dual AGN system two pairs of bi-symmetric arms, as are expected from the numerical simulations of such system. Being one of a few confirmed kiloparsec-scale dual AGNs exhibiting a clear morphological structure of the host galaxies, J0038+4128 provides an unique opportunity to study the co-evolution of the host galaxies and their central supermassive black holes undergoing a merging process.
123928525
Kaonic nuclei in the Skyrme-Hartree-Fock approach
National Natural Science Foundation of China [10975116, 11275160]; Fundamental Research Funds for the Central Universities [2010121011]
54736542
Lambda hyperons and the neutron drip line
National Science Foundation of China [10605018]; New Century Excellent Talents in University [NCET-07-0730]; Ministerio de Educacion y Ciencia [FIS2005-03142]; Generalitat de Catalunya [2005SGR-00343]
123014665
EFFECT OF TENSOR INTERACTION ON HEAVY AND SUPERHEAVY NUCLEI
The effect of tensor interaction is discussed on the deformation and the shell structure of heavy and superheavy nuclei within the deformed Skyrme Hartree-Fock+BCS model. The importance of the tensor correlations is shown for the single particle spectra of protons in 249Bk. The large shell gaps of superheavy nuclei are found at Z = 114 and Z = 120 for protons and N = 184 for neutrons with the spherical shape irrespective of the tensor correlations. It is also shown that Z = 114 and N = 164 shell gaps are more pronounced by the tensor correlations in the case of SLy5+T interaction.
121212177
Hypernuclei in the deformed Skyrme-Hartree-Fock approach
The properties of Lambda hypernuclei in a broad mass region are studied by using a deformed Hartree-Fock approach using realistic nucleonic Skyrme forces, pairing correlations, and a microscopically determined lambda-nucleon interaction based on Brueckner-Hartree-Fock calculations of hypernuclear matter. The results suggest that the core nuclei and the corresponding hypernuclei have similar deformations with the same sign. Some light single-Lambda hypernuclei are substantially deformed and the Lambda binding energy is modified by the deformation.
121260335
Weakly bound neutrons and quadrupole response function in the many-body pair correlation of neutron drip line nuclei
A simplified model of the Hartree-Fock Bogoliubov (HFB) equation with surface-type or volume-type pairing is solved in coordinate space with the correct asymptotic boundary conditions. By using the resulting HFB wavefunctions, the low-energy quadrupole (L = 2) response function is studied for the system with weakly bound s and d neutrons. As the binding energy of the neutrons becomes small or approaches zero, the discrete solutions of the HFB equation disappear. Then, without any further correlation ( for example, random phase approximation ( RPA) correlation), the threshold quadrupole response becomes broader and moves toward very low excitation energies, while the total strength increases very rapidly. The important role of the continuum character of the upper component u(lj) (r) of the HFB s(1/2) wavefunction in the increasing strength is pointed out. The large and broad quadrupole response with a very low peak energy is expected for neutron drip line nuclei with N approximate to 56 and Z approximate to 28, of which both the neutron 2d(5/2) and 3s(1/2) orbits may be weakly bound in the Hartree-Fock (HF) potential. (Less)