Broad Asymmetric Line Research Articles

Fast Outflows in Hot Dust-obscured Galaxies Detected with Keck/NIRES

Abstract We present rest-frame optical spectroscopic observations of 24 Hot Dust-Obscured Galaxies (Hot DOGs) at redshifts 1.7–4.6 with KECK/NIRES. Our targets are selected, based on their extreme red colors, to be the highest-luminosity sources from the WISE infrared survey. In 20 sources with well-detected emission, we fit the key [O iii], Hβ, Hα, [N ii], and [S ii] diagnostic lines to constrain physical conditions. Of the 17 targets with a clear detection of the [O iii]λ5007 Å emission line, 15 display broad blueshifted and asymmetric line profiles, with widths ranging from 1000 to 8000 km s−1 and blueshifts up to 3000 km s−1. These kinematics provide strong evidence for the presence of massive ionized outflows of up to , with a median of . As many as eight sources show optical emission line ratios consistent with vigorous star formation. Balmer-line star formation rates, uncorrected for reddening, range from 30 to 1300 , with a median of . Estimates of the SFR from Spectral Energy Distribution fitting of mid- and far-infrared photometry suggest significantly higher values. We estimate the central black hole masses to be of order , assuming the present-day relation. The bolometric luminosities and the estimated masses of the central black holes of these galaxies suggest that many of the active galactic nucleus-dominated Hot DOGs are accreting at or above their Eddington limit. The combination of ongoing star formation, massive outflows, and high Eddington ratios suggest Hot DOGs are a transitional phase in galaxy evolution.

An Evolving Broad Iron Line from the First Galactic Ultraluminous X-Ray Pulsar Swift J0243.6+6124

We present a spectral study of the ultraluminous Be/X-ray transient pulsar Swift J0243.6+6124 using Neutron Star Interior Composition Explorer (NICER) observations during the system's 2017--2018 giant outburst. The 1.2--10~keV energy spectrum of the source can be approximated with an absorbed cut-off power law model. We detect strong, luminosity-dependent emission lines in the 6--7 keV energy range. A narrow 6.42 keV line, observed in the sub-Eddington regime, is seen to evolve into a broad Fe-line profile in the super-Eddington regime. Other features are found at 6.67 and 6.97 keV in the Fe-line complex. An asymmetric broad line profile, peaking at 6.67 keV, is possibly due to Doppler effects and gravitational redshift. The 1.2--79 keV broadband spectrum from NuSTAR and NICER observations at the outburst peak is well described by an absorbed cut-off power law plus multiple Gaussian lines and a blackbody component. Physical reflection models are also tested to probe the broad iron line feature. Depending on the mass accretion rate, we found emission sites that are evolving from ~5000 km to a range closer to the surface of the neutron star. Our findings are discussed in the framework of the accretion disk and its implication on the magnetic field, the presence of optically thick accretion curtain in the magnetosphere, jet emission, and the massive, ultra-fast outflow expected at super-Eddington accretion rates. We do not detect any signatures of a cyclotron absorption line in the NICER or NuSTAR data.

EPR and Magnetometry of Mixed Phases in FeVO4\u2013Co3V2O8 System

Magnetic properties of five samples obtained in reactions between nFeVO4 and (1 − n)Co3V2O8 (with the composition index n = 0.54, 0.50, 0.40, 0.30 and 0.20) have been investigated by dc magnetometry and electron paramagnetic resonance (EPR). The investigated samples contained two phases: one having lyonsite-type structure and the other Co3V2O8. Temperature dependence of dc magnetic susceptibility showed the Curie–Weiss paramagnetic behaviour with a strong antiferromagnetic (AFM) interaction in the high-temperature range leading to magnetic transitions at 6 and 12 K. For all samples, the magnetic hysteresis loop in isothermal magnetisation was registered at T = 5 K indicating the existence of a ferromagnetic component. Samples n = 0.54 and 0.50 displayed a large coercive field and remanent magnetisation in contrast to the other three samples due to higher content of the lyonsite-type structure. EPR spectra of the studied samples showed a broad asymmetric line that was decomposed on lorentzian or gaussian components. Temperature dependence of the spectral parameters (resonance field, linewidth, integrated intensity) of these components was studied in high-temperature range (T > 90 K). The observed spectra were attributed to different types of magnetic spin clusters.

Tuning of physical properties of Fe7(PO4)6 by sodium intercalation

The sodium intercalation of mixed – valence iron phosphate Fe32+Fe43+(PO4)6 results in drastic transformation of its physical properties. The parent compound Fe7(PO4)6 reaches magnetically ordered state through succession of phase transitions at TN1 = 45.5 K and TN2 = 16 K marked by sharp singularities in both specific heat Cp and magnetic susceptibility χ. The introduction of sodium suppresses the formation of antiferromagnetic state down to TN = 33 K in Na0.65Fe7(PO4)6. The low temperature phase transition in this compound smears being substituted by broad anomalies in magnetization and specific heat related to the spin/charge disorder effects. The sharp well resolved electron spin resonance spectra in parent material transform into asymmetric broad line in sodium – intercalated substance. The dielectric permittivity ε of Fe7(PO4)6 demonstrates a kink at TN2, while no singularity marks TN1. No features accompany magnetic phase transition in dielectric property of Na0.65Fe7(PO4)6 but ε reaches the relaxation maxima at high temperatures which can be attributed to the freezing of sodium ions.

The intrinsic Baldwin effect in broad Balmer lines of six long-term monitored AGNs

We investigate the intrinsic Baldwin effect (Beff) of the broad H$\alpha$ and H$\beta$ emission lines for six Type 1 active galactic nuclei (AGNs) with different broad line characteristics: two Seyfert 1 (NGC 4151 and NGC 5548), two AGNs with double-peaked broad line profiles (3C 390.3 and Arp 102B), one narrow line Seyfert 1 (Ark 564), and one high-luminosity quasar with highly red asymmetric broad line profiles (E1821+643). We found that a significant intrinsic Beff was present in all Type 1 AGNs in our sample. Moreover, we do not see strong difference in intrinsic Beff slopes in different types of AGNs which probably have different physical properties, such as inclination, broad line region geometry, or accretion rate. Additionally, we found that the intrinsic Beff was not connected with the global one, which, instead, could not be detected in the broad H$\alpha$ or H$\beta$ emission lines. In the case of NGC 4151, the detected variation of the Beff slope could be due to the change in the site of line formation in the BLR. Finally, the intrinsic Beff might be caused by the additional optical continuum component that is not part of the ionization continuum.

Magnetic performance of orthorhombic Mn35Ge35Te30 nanocrystals

Nanocrystalline antiferromagnetic Mn35Ge35Te30 diluted magnetic semiconductors powder syntheses by the conventional direct reaction of pure metals. Nanocrystalline nature of the prepared sample confirmed using various techniques, where x-Ray diffraction (XRD) and atomic force microscope (AFM) measurements shows ~96nm particle size, while transmission electron microscope (TEM) shows 92nm particle size. XRD analysis show orthorhombic symmetry with lattice parameters a=7.386611±(0.0066)Å, b=8.962502±(0.0090)Å and c=7.027349±(0.0040)Å. Electron Spin resonance (ESR) show a broad asymmetric line whereas the remnant Mn2+ six-hyperfine lines are broadened within |+1/2>→|−1/2> line according to high anisotropy; calculated Landé g-factor is 2.047. Vibrating sample magnetometer (VSM) analysis, field-moment characteristics revealed a hysteresis loop with small coercive field indicating that Mn35Ge35Te30 is a soft magnetic material. Moreover, hysteresis measurements at different temperatures show increasing magnetization with increasing temperature up to 150K followed by decreased with increasing temperature up to 300K. This behavior indicated to the antiferromagnetic nature of the prepared nanocrystalline materials. Magnetic moment – temperature measurements show Néel temperature TN=172.6K. Magnetic force microscope revealed magnetic domains as a result of interaction between magnetic dipole moments of magnetic cantilever and pressed powder.

3-cm FINE STRUCTURE MASERS: A UNIQUE SIGNATURE OF SUPERMASSIVE BLACK HOLE FORMATION VIA DIRECT COLLAPSE IN THE EARLY UNIVERSE

ABSTRACT The direct collapse black hole (DCBH) scenario describes the isothermal collapse of a pristine gas cloud directly into a massive, M BH = ?> 104–106 M ⊙ ?> black hole. In this paper we show that large H i column densities of primordial gas at T ∼ 10 4 ?> K with low molecular abundance—which represent key aspects of the DCBH scenario—provide optimal conditions for the pumping of the 2p-level of atomic hydrogen by trapped Lyα photons. This Lyα pumping mechanism gives rise to an inverted level population of the 2 s 1 / 2 − 2 p 3 / 2 ?> transition, and therefore also gives rise to stimulated fine structure emission at λ = 3.04 cm ?> (rest-frame). We show that simplified models of the DCBH scenario amplify the CMB by up to a factor of ∼ 10 5 ?> , above which the maser saturates. Hyperfine splitting of the 3 cm transition gives rise to a characteristic broad (FWHM ∼ tens of MHz in the observers frame) asymmetric line profile. This signal subtends an angular scale of ∼1–10 mas, which translates to a flux of ∼0.3–3 μJy, which is detectable with ultra-deep surveys being planned with SKA1-MID. While challenging, as the signal is visible for a fraction of the collapse time of the cloud, the matching required physical conditions imply that a detection of the redshifted 3-cm emission line could provide direct evidence for the DCBH scenario.

Experimental study of magnetic anisotropy in a layered CsNd(MoO4)2

Ground-state properties of Nd3+ ion in the magnetically concentrated CsNd(MoO4)2 lattice of orthorhombic symmetry have been investigated at low temperatures. Magnetic-field dependence of magnetization measured at 5K in the magnetic field applied along the a, b, c crystallographic axes reflects slight deviations from the tetragonal symmetry of a local surrounding of Nd3+ ion. The analysis of the data performed within a model of an ideal paramagnet provided g-factor values, ga=3.08, gb=1.90, and gc=1.95. Angular dependence of the electron paramagnetic resonance spectra studied at temperature 2.5K was investigated in the ab, ac and bc planes. The spectra are dominated by a broad asymmetric line which is strongly deformed due to the formation of a fine structure ascribed to the presence of nonequivalent Nd3+ sites. The analysis of the spectra confirmed the easy-axis character of a magnetic anisotropy. In addition, nontrivial tilting of the local anisotropy axes from the crystallographic axes was revealed, indicating lowering of crystal symmetry at low temperatures.

Investigating the Structural Origin of Trpzip2 Temperature Dependent Unfolding Fluorescence Line Shape Based on a Markov State Model Simulation

Vibrationally resolved fluorescence spectra of the β-hairpin trpzip2 peptide at two temperatures as well as during a T-jump unfolding process are simulated on the basis of a combination of Markov state models and quantum chemistry schemes. The broad asymmetric spectral line shape feature is reproduced by considering the exciton-phonon couplings. The temperature dependent red shift observed in the experiment has been attributed to the state population changes of specific chromophores. Through further theoretical study, it is found that both the environment's electric field and the chromophores' geometry distortions are responsible for tryptophan fluorescence shift.

Validating classical line profile analyses using microbeam diffraction from individual dislocation cell walls and cell interiors

Dislocation structures in deformed metals produce broad asymmetric diffraction line profiles. During analysis, these profiles are generally separated into two nearly symmetric subprofiles corresponding to diffraction by dislocation cell walls and cell interiors. These subprofiles are then interpreted using complex models of dislocation-based line broadening. Until now, it has not been possible to test the many assumptions that are made in such an analysis. Here, depth-resolved microbeam diffraction was used to measure diffraction line profiles from numerous individual dislocation cell walls and cell interiors in a heavily deformed Cu single crystal. Summing these profiles directly constructed the cell-interior and cell-wall subprofiles that have been approximated in the line profile analysis literature for the past 30 years. Direct comparison between the reconstructed subprofiles and the macroscopic asymmetric line profile from the same sample allows the first direct tests of many of the assumptions that have been used for interpreting these X-ray measurements.

EXTREMELY BROAD RADIO RECOMBINATION MASER LINES TOWARD THE HIGH-VELOCITY IONIZED JET IN CEPHEUS A HW2

We present the first detection of the H40a, H34a and H31a radio recombination lines (RRLs) at millimeter wavelengths toward the high-velocity, ionized jet in the Cepheus A HW2 star forming region. From our single-dish and interferometric observations, we find that the measured RRLs show extremely broad asymmetric line profiles with zero-intensity linewidths of ~1100 kms-1. From the linewidths, we estimate a terminal velocity for the ionized gas in the jet of >500 kms-1, consistent with that obtained from the proper motions of the HW2 radio jet. The total integrated line-to-continuum flux ratios of the H40a, H34a and H31a lines are 43, 229 and 280 kms-1, clearly deviating from LTE predictions. These ratios are very similar to those observed for the RRL maser toward MWC349A, suggesting that the intensities of the RRLs toward HW2 are affected by maser emission. Our radiative transfer modeling of the RRLs shows that their asymmetric profiles could be explained by maser emission arising from a bi-conical radio jet with a semi-aperture angle of 18 deg, electron density distribution varying as r^(-2.11) and turbulent and expanding wind velocities of 60 and 500 kms-1.

Photoluminescence study of epitaxially grown ZnSnAs2:Mn thin films

The photoluminescence (PL) properties of heavily Mn-doped ZnSnAs2 layers epitaxially grown on nearly lattice-matched semi-insulating InP substrates are studied. PL spectra are obtained for samples with Mn concentrations of 5, 12 and 24 mol% relative to the combined concentrations of Zn and Sn. A broad emission band centered at ∼ 1 eV is detected for Mn-doped layers at room temperature. The emission is a intense broad asymmetric line at low temperatures. The line is reconstructed by superposition of two bands with peak energies of ∼ 0.99 and 1.07 eV, similar to those reported for InP. These bands are superimposed onto a 1.14 eV band with well-resolved phonon structure for the layer doped with 12 % Mn. Recombination mechanism involving the split-off band of the ZnSnAs2 is suggested. Temperature dependence of integrated intensities of the PL bands indicates to thermally activated emission with activation energies somewhat different from those found for InP. Mn substitution at cationic sites increases the concentration of holes which may act as recombination centers. Recombination to the holes bound to Mn ions with the ground state located below the top of the valence band has been proposed as a possible PL mechanism.

IDENTIFYING SUPERMASSIVE BLACK HOLE BINARIES WITH BROAD EMISSION LINE DIAGNOSIS

Double-peaked broad emission lines in Active Galactic Nuclei (AGNs) may indicate the existence of a bound supermassive black hole (SMBH) binary where two distinct broad line regions (BLRs) contribute together to the line profile. An alternative interpretation is a disk emitter origin for the double-peaked line profile. Using simple BLR models, we calculate the expected broad line profile for a SMBH binary at different separations. Under reasonable assumptions that both BLRs are illuminated by the two active SMBHs and that the ionizing flux at the BLR location is roughly constant, we confirm the emergence of double-peaked features and radial velocity drifts of the two peaks due to the binary orbital motion. However, such a clear double-peaked feature only arises in a particular stage of the binary evolution when the two BHs are close enough such that the line-of-sight orbital velocity difference is larger than the FWHM of the individual broad components, while the two BLRs are still mostly distinct. Prior to this stage, the velocity splitting due to the orbit motion of the binary is too small to separate the emission from the two BLRs, leading to asymmetric broad line profiles in general. When the two BHs are even closer such that the two BLRs can no longer be distinct, the line profile becomes more complex and the splitting of the peaks does not correspond to the orbital motion of the binary. In this regime there are no coherent radial velocity drifts in the peaks with time. Asymmetric line profiles are probably a far more common signature of binary SMBHs than are double-peaked profiles. We discuss the temporal variations of the broad line profile for binary SMBHs and highlight the different behaviors of reverberation mapping in the binary and disk emitter cases, which may serve as a feasible tool to disentangle these two scenarios.

NMR and DFT study of chemical bonding of the titanyl ion in pentafluoro complexes (NH4)3TiOF5 and Rb2KTiOF5

19F NMR and DFT methods are used to study the electronic structure and chemical bonding of titanyl ions in pentafluoro titanyl complexes (NH4)3TiOF5 and Rb2KTiOF5. The experimental values of the anisotropy of 19F NMR chemical shifts (CSs) are shown to be consistent with the calculated parameters within the DFT method. At normal temperatures orientational disordering of octahedral [TiOF5]3- anions occurs, fluorine atoms steadily occupying cis- and trans-positions with respect to the O2- ion. In both complexes, trans-position is not fully occupied; the occupation ratio does not exceed ~4:0.9. When the temperature is decreased to 150 K, the value of the CS anisotropy of the fluorine atom resonance line in trans-position is found to be smaller than the dipole-dipole broadening, whereas the line from fluorine atoms in cis-positions transforms into an asymmetric broad line characterized by the triaxial anisotropy of the CS tensor. It is shown that the found anisotropy corresponds to violation of the axial symmetry of Ti—F cis bonds because of strong delocalization of the electron density of Ti—O bonds in the titanyl ion.

DISK REFLECTION SIGNATURES IN THE SPECTRUM OF THE BRIGHT Z-SOURCE GX 340+0

We present the preliminary results of a 50 ks long XMM-Newton observation of the bright Z-source GX 340+0. In this Letter we focus on the study of a broad asymmetric emission line in the Fe K alpha energy band, whose shape is clearly resolved and compatible with a relativistically smeared profile arising from reflection on a hot accretion disk extending close to the central accreting neutron star. By combining temporal and spectral analysis, we are able to follow the evolution of the source along its Horizontal Branch. However, despite a significant change in the continuum emission and luminosity, the line profile does not show any strong correlated variation. This broad line is produced by recombination of highly ionized iron (Fe XXV) at an inferred inner radius close to 13 gravitational radii while the fit requires a high value for the outer disk radius. The inclination of the source is extremely well constrained at 35 deg, while the emissivity index is -2.50.

A SEARCH FOR IRON EMISSION LINES IN THECHANDRAX-RAY SPECTRA OF NEUTRON STAR LOW-MASS X-RAY BINARIES

While iron emission lines are well studied in black hole systems, both in X-ray binaries and Active Galactic Nuclei, there has been less of a focus on these lines in neutron star low-mass X-ray binaries (LMXBs). However, recent observations with Suzaku and XMM-Newton have revealed broad asymmetric iron line profiles in 4 neutron star LMXBs, confirming an inner disk origin for these lines in neutron star systems. Here, we present a search for iron lines in 6 neutron star LMXBs. For each object we have simultaneous Chandra and RXTE observations at 2 separate epochs, allowing for both a high resolution spectrum, as well as broadband spectral coverage. Out of the six objects in the survey, we only find significant iron lines in two of the objects, GX 17+2 and GX 349+2. However, we cannot rule out that there are weak, broad lines present in the other sources. The equivalent width of the line in GX 17+2 is consistent between the 2 epochs, while in GX 349+2 the line equivalent width increases by a factor of ~3 between epochs as the source flux decreases by a factor of 1.3. This suggests that the disk is highly ionized, and the line is dominated by recombination emission. We find that there appears to be no specific locations in the long-term hardness-intensity diagrams where iron emission lines are formed, though more sources and further observations are required.

Suppression of the low-spin multiplet components in the3pphotoelectron spectra of atomic and solid3dmetals

The $3p$ photoelectron spectra of Cr, Mn, Fe, and Co atoms have been studied experimentally and theoretically. The $3p$-$3d$ interaction in the final ionic state gives rise to an $\mathrm{LS}$ multiplet structure spanning a binding-energy range of around 20 eV. The prominent high-spin components at low binding energies contrast with the broad and weak low-spin components at high binding energies. Term-dependent lifetime broadening by super-Coster-Kronig decays is the main cause of the almost complete suppression of the latter lines. The corresponding $3p$ photoelectron spectra of the metals display only a single broad asymmetric line. The influence of correlation on the $3p$ photoelectron spectra is shown to be less dramatic than in the case of the better known $3s$ photoelectron spectra. We show that, while the peculiarities in the $3s$ spectrum are caused by configuration interaction, the single-configuration approximation already provides the clue to the interpretation of the $3p$ spectrum.

Anomalous R-Line Behaviour in Nanocrystalline Al2O3:Cr3+

The photoluminescence spectra of Al 2 O 3 :Cr 3+ nanopowder under excitation by a frequency-doubled YAG:Nd laser (λ ex = 532 nm) and a nitrogen-vapour pulsed laser (λ ex = 337.1 nm) have been studied. A considerable difference between the spectra of nanocrystalline and macrocrystalline samples has been observed. The nanocrystalline samples reveal a broad asymmetric line with the maximum at 690 nm under the YAG:Nd excitation, whereas under the nitrogen-vapour laser excitation, the broad line becomes more symmetric, and its maximum shifts by 45 nm to the longer-wavelength region. The above shift is shown to be due to a drastic change in the Huang-Rhys parameter of the 2 E- 4 A 2 transition. A decay of the broad line with the increase of the duration of UV illumination has been observed.

Effect of Ar +, N 2+, He + and H 2+ bombardment on the composition and structure of CN x layers

Amorphous CN x layers of high N-content, close to CN stoichiometry, were prepared by reacting a graphite target with nitrogen in DC plasma. The CN layers were subjected to 2 keV Ar +, He +, H 2 + and also to 2 and 4 keV N 2 + bombardment at fluences in the range of 10 15–10 17 ions/cm 2. Changes in chemical composition and structure were followed by X-ray photoelectron and Infra red spectroscopy. The broad asymmetric C1s and N1s line shapes manifested several bonding states assignable by IR mainly to single and conjugated CN and also a small amount of CN species. Ion bombardment caused preferential removal of N with simultaneous formation of different C–C bonds. Conjugated CN bonds seemed to be more stable at ion bombardment than the other C–N type bonds. No evidence of appreciable transformation to the favourable sp 3 C–N species could be detected.

Deuteron resonance studies in CeNiInD x system

Deuteron NMR studies have been performed in CeNiInD x system ( x = 0.33 and 1.01) in the temperature range 150–300 K. For x = 0.33, a single broad asymmetric resonance line appears at all temperatures. This means that the rapid diffusion of deuteron atoms averages out the quadrupolar splitting and hence a single line results. On the other hand for x = 1.01, observation of quadrupolar splitted resonance lines indicates that deuterons occupy two non-equivalent interstitial sites. The quadrupolar interaction parameters are obtained by fitting the experimental spectra with η = 0 and are compared with those obtained from a point charge calculation. Most probable sites for deuterons in CeNiInD 1.01 system are then proposed.