3,439 research outputs found

    Outflows, Inflows and Young Stars in the inner 200 pc of the Seyfert galaxy NGC 2110

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    We present a two-dimensional mapping of stellar population age components, emission-line fluxes, gas excitation and kinematics within the inner ∼200\sim200 pc of the Seyfert 2 galaxy NGC 2110. We used the Gemini North Integral Field Spectrograph (NIFS) in the J and K bands at a spatial resolution of ∼22\sim22 pc. The unresolved nuclear continuum is originated in combined contributions of young stellar population (SP; age≤100\leq100 Myr), a featureless AGN continuum and hot dust emission. The young-intermediate SP (100<100<age≤700\leq700 Myr) is distributed in a ring-shaped structure at ≈140\approx140 pc from the nucleus, which is roughly coincident with the lowest values of the stellar velocity dispersion. In the inner ≈115\approx115 pc the old SP (age>2>2 Gyr) is dominant. The [FeII]1.25μ\mum emission-line flux distribution is correlated with the radio emission and its kinematics comprise two components, one from gas rotating in the galaxy plane and another from gas in outflow within a bicone oriented along north-south. These outflows seem to originate in the interaction of the radio jet with the ambient gas producing shocks that are the main excitation mechanism of the [FeII] emission. We estimate: (1) an ionized gas mass outflow rate of ∼0.5\sim0.5 M⊙_\odot/yr at ∼\sim70 pc from the nucleus; and (2) a kinetic power for the outflow of only 0.05% of the AGN bolometric luminosity implying weak feedback effect on the galaxy.Comment: Accepted for publication in MNRA

    Ecological aspects of lepidopteran caterpillar parasitoids from Caryocar brasiliense Camb. (Caryocaraceae) in a cerrado sensu stricto of Central Brazil.

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    Made available in DSpace on 2018-06-07T01:02:19Z (GMT). No. of bitstreams: 1 fullpaper.pdf: 376397 bytes, checksum: a3cc0565fd56842f20d11872fdcf936e (MD5) Previous issue date: 2008-02-15bitstream/item/178237/1/fullpaper.pd

    Disentangling the near infrared continuum spectral components of the inner 500 pc of Mrk 573: two-dimensional maps

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    We present a near infrared study of the spectral components of the continuum in the inner 500×\times500 pc2^2 of the nearby Seyfert galaxy Mrk573 using adaptive optics near-infrared integral field spectroscopy with the instrument NIFS of the Gemini North Telescope at a spatial resolution of ∼\sim50 pc. We performed spectral synthesis using the {\sc starlight} code and constructed maps for the contributions of different age components of the stellar population: young (age≤100age\leq100 Myr), young-intermediate (100<age≤700100<age\leq700 Myr), intermediate-old (700700 Myr 22 Gyr) to the near-IR K-band continuum, as well as their contribution to the total stellar mass. We found that the old stellar population is dominant within the inner 250 pc, while the intermediate age components dominate the continuum at larger distances. A young stellar component contributes up to ∼\sim20% within the inner ∼\sim70 pc, while hot dust emission and featureless continuum components are also necessary to fit the nuclear spectrum, contributing up to 20% of the K-band flux there. The radial distribution of the different age components in the inner kiloparsec of Mrk573 is similar to those obtained by our group for the Seyfert galaxies Mrk1066, Mrk1157 and NGC1068 in previous works using a similar methodology. Young stellar populations (≤\leq100 Myr) are seen in the inner 200-300 pc for all galaxies contributing with ≥\ge20% of the K-band flux, while the near-IR continuum is dominated by the contribution of intermediate-age stars (t=t=100 Myr-2 Gyr) at larger distances. Older stellar populations dominate in the inner 250 pc

    Inhibition of HIV cell-to-cell fusion by antiretroviral drugs and neutralizing antibodies

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    Poster presented at the 7th iMed.ULisboa Postgraduate Students Meeting. Lisbon, 15 July 2015"Inhibition of HIV cell entry by antiretroviral drugs and neutralizing antibodies (NAbs) is typically measured in assays where cell-free virions enter reporter cell lines. However, direct Env-mediated cell-to-cell transmission is a major mechanism of HIV infection that also needs to be targeted. In this work we aimed to determine the ability of anti-HIV compounds in clinical or research use to inhibit HIV mediated cell-to-cell fusion (syncytia formation)."Fundação para a Ciência e a Tecnologia - Portugal ; European Unio

    Gemini NIFS survey of feeding and feedback processes in nearby Active Galaxies: I - Stellar kinematics

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    We use the Gemini Near-Infrared Integral Field Spectrograph (NIFS) to map the stellar kinematics of the inner few hundred parsecs of a sample of 16 nearby Seyfert galaxies, at a spatial resolution of tens of parsecs and spectral resolution of 40 km/s. We find that the line-of-sight (LOS) velocity fields for most galaxies are well reproduced by rotating disk models. The kinematic position angle (PA) derived for the LOS velocity field is consistent with the large scale photometric PA. The residual velocities are correlated with the hard X-ray luminosity, suggesting that more luminous AGN have a larger impact in the surrounding stellar dynamics. The central velocity dispersion values are usually higher than the rotation velocity amplitude, what we attribute to the strong contribution of bulge kinematics in these inner regions. For 50% of the galaxies, we find an inverse correlation between the velocities and the h3h_3 Gauss-Hermitte moment, implying red wings in the blueshifted side and blue wings in the redshifted side of the velocity field, attributed to the movement of the bulge stars lagging the rotation. Two of the 16 galaxies (NGC 5899 and Mrk 1066) show an S-shape zero velocity line, attributed to the gravitational potential of a nuclear bar. Velocity dispersion maps show rings of low-σ\sigma values (50-80 km/s) for 4 objects and "patches" of low-sigma for 6 galaxies at 150-250 pc from the nucleus, attributed to young/ intermediate age stellar populations.Comment: To be published in MNRA
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