95 research outputs found

    IR Mergers and IR QSOs with Galactic Winds. II. NGC 5514, two Extra-nuclear Starburts/LINERs with a Supergiant Bubble in the Rupture Phase

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    A study of morphology, kinematics and ionization structure of the IR merger NGC 5514, is presented. This study is based mainly on Integral 2D spectroscopy obtained on 4.2 m William Herschel Telescope (La Palma, Spain) and data from CASLEO (Argentina). Clear evidence of two extra-nuclear starbursts with young outflows and LINER activity are reported. One of these outflow generate a supergiant bubble, where the emission lines and kinematics maps show 4 extended ejections. These results suggest that the bubble is in the rupture phase.Comment: 32 pages, 30 figures, corrected version (accepted MNRAS

    Integral Field Spectroscopy of the Central Regions of 3C 120: Evidence of a Past Merging Event

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    IFS combined with HST WFPC imaging were used to characterize the central regions of the Seyfert 1 radio galaxy 3C 120. We carried out the analysis of the data, deriving intensity maps of different emission lines and the continua at different wavelengths from the observed spectra. Applying a 2D modeling to the HST images we decoupled the nucleus and the host galaxy, and analyzed the host morphology. The host is a highly distorted bulge dominated galaxy, rich in substructures. We developed a new technique to model the IFS data extending the 2D modeling. Using this technique we separated the Seyfert nucleus and the host galaxy spectra, and derived a residual data cube with spectral and spatial information of the different structures in 3C 120. Three continuum-dominated structures (named A, B, and C) and other three extended emission line regions (EELRs, named E1, E2 and E3) are found in 3C 120 which does not follow the general behavior of a bulge dominated galaxy. We also found shells in the central kpc that may be remnants of a past merging event in this galaxy. The origin of E1 is most probably due to the interaction of the radio-jet of 3C 120 with the intergalactic medium. Structures A, B, and the shell at the southeast of the nucleus seem to correspond to a larger morphological clumpy structure that may be a tidal tail, consequence of the past merging event. We found a bright EELR (E2) in the innermost part of this tidal tail, nearby the nucleus, which shows a high ionization level. The kinematics of the E2 region and its connection to the tidal tail suggest that the tail has channeled gas from the outer regions to the center.Comment: 55 pages, 18 figures and 5 tables Accepted by AP

    A High Pressure Operando Spectroscopy Examination of Bimetal Interactions in ‘Metal Efficient’ Palladium/In2O3/Al2O3 Catalysts for CO2 Hydrogenation

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    CO2 hydrogenation to methanol has the potential to serve as a sustainable route to a wide variety of hydrocarbons, fuels and plastics in the quest for net zero. Synergistic Pd-In2O3 (Palladium on Indium Oxide) catalysts show high CO2 conversion and methanol selectivity, enhancing methanol yield. The identity of the optimal active site for this reaction is unclear, either as a Pd−In alloy, proximate metals, or distinct sites. In this work, we demonstrate that metal-efficient Pd-In2O3 species dispersed on Al2O3 can match the performance of pure Pd-In2O3 systems. Further, we follow the evolution of both Pd and In sites, and surface species, under operando reaction conditions using X-ray Absorption Spectroscpy (XAS) and infrared (IR) spectroscopy. In doing so, we can determine both the nature of the active sites and the influence on the catalytic mechanism

    Rosiglitazone Rescues Memory Impairment in Alzheimer's Transgenic Mice: Mechanisms Involving a Reduced Amyloid and Tau Pathology

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    Clinical studies suggest that agonists at peroxisome proliferator-activated receptor gamma (PPARγ) may exert beneficial effects in patients with mild-to-moderate Alzheimer's disease (AD), but the mechanism for the potential therapeutic interest of this class of drugs has not yet been elucidated. Here, in mice overexpressing mutant human amyloid precursor protein, we found that chronic treatment with rosiglitazone, a high-affinity agonist at PPARγ, facilitated β-amyloid peptide (Aβ) clearance. Rosiglitazone not only reduced Aβ burden in the brain but, importantly, almost completely removed the abundant amyloid plaques observed in the hippocampus and entorhinal cortex of 13-month-old transgenic mice. In the hippocampus, neuropil threads containing phosphorylated tau, probably corresponding to dystrophic neurites, were also decreased by the drug. Rosiglitazone switched on the activated microglial phenotype, promoting its phagocytic ability, reducing the expression of proinflammatory markers and inducing factors for alternative differentiation. The decreased amyloid pathology may account for the reduction of p-tau-containing neuropil threads and for the rescue of impaired recognition and spatial memory in the transgenic mice. This study provides further insights into the mechanisms for the beneficial effect of rosiglitazone in AD patients

    Feeding versus Feedback in NGC 4151 probed with Gemini NIFS. I. Excitation

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    We have used the Gemini Near-infrared Integral Field Spectrograph (NIFS) to map the emission-line intensity distributions and ratios in the Narrow-Line Region (NLR) of the Seyfert galaxy NGC 4151 in the Z, J, H and K bands at a resolving power ~ 5000, covering the inner 200 pc x 300 pc of the galaxy at a spatial resolution of 8 pc. We present intensity distributions I(r) in 14 emission lines. (1) For the ionized gas, I(r) is extended to ~ 100 pc from the nucleus along pos. angle PA=60/240 deg-- NE--SW), consistent with an origin in the known biconical outflow; while for the recombination lines I(r) ~ r^-1, for the forbidden lines I(r) is flat (r^0). (2) The H_2 emission lines intensity distributions avoid the region of the bicone, extending to r ~ 60 pc, perpendicular to the bicone axis, supporting an origin for the H_2-emitting gas in the galaxy plane. (3) The coronal lines show a steep intensity profile, described by r^-2. Using the line-ratio maps [Fe II]1.644/1.257 and Pa_b/Br_g we obtain a reddening of E(B-V)~0.5 along the NLR and E(B-V)>1 at the nucleus. Our line-ratio map [Fe II] 1.257/[P II] 1.189 is the first such map of an extragalactic source. Together with the [Fe II]/Pa_b map, these line ratios correlate with the radio intensity distribution, mapping the effects of shocks produced by the radio jet, which probably release the Fe locked in grains and produce the enhancement of the [Fe II] emission observed at ~ 1 arcsec from the nucleus. At these regions, we obtain densities N_e ~4000 cm^-3 and temperatures T_e ~ 15000K for the [Fe II]-emitting gas. For the H_2-emitting gas we obtain T ~ 2100K. The distinct intensity distributions, physical properties and locations of the ionized and molecular gas suggest that the H_2-emitting gas traces the AGN feeding, while the ionized gas traces its feedback.Comment: 22 pages. 14 figures, accepted for publication in MNRA

    GEMINI 3D spectroscopy of BAL+IR+Fe II QSOs: II. IRAS 04505-2958 an explosive QSO with hypershell and a new scenario for galaxy formation and galaxy end

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    From a study of BAL + IR + Fe II QSOs (using deep Gemini GMOS-IFU spectroscopy) new results are presented: for IRAS 04505-2958. Specifically, we have studied in detail the out flow (OF) process and their associated structures, mainly at two large galactic scales: (i) two blobs/shells (S1, S2) at radius r = 1.1 and 2.2 kpc; and (ii) an external hypergiant shell (S3) at r = 11 kpc. In addition, the presence of two very extended hypergiant shells (S4, S5) at r = 80 kpc is discussed. From this GMOS study the following main results were obtained: (i) For the external hypergiant shell S3 the kinematics GMOS maps of the ionized gas show very similar features to those observed for the prototype of exploding external supergiant shell: in NGC 5514. (ii) The main knots K1, K2 and K3 -of this hypergiant shell S3- show a stellar population and emission line ratios associated with the presence of a starburst + OF/shocks. (iii) The internal shells S1 and S2 show structures, OF components and properties very similar to those detected in the nuclear shells of Mrk 231. (iv) The shells S1+S2 and S3 are aligned at PA = 131: i.e. suggesting that the OF process is in the blow-out phase with bipolar structure. In addition, the shells S4 and S5 (at 80-100 kpc scale) are aligned at PA = 40, i.e.: a bipolar OF perpendicular to the internal OF. Finally, the generation of UHE cosmic rays and neutrino/ dark-matter -associated with HyNe in BAL + IR + Fe II QSOs- is discussed.Comment: Submitted MNRAS, 81 pages, 25 Figure

    Double Toil and Trouble: Grade Retention and Academic Performance

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