We present HST/ACS observations of ten galaxies that host narrow-line Seyfert 1 (NLS1) nuclei, believed to contain relatively smaller mass black holes accreting at high Eddington ratios. We deconvolve each ACS image into a nuclear point source (AGN), a bulge, and a disk, and fitted the bulge with a Sersic profile and the disk with an exponential profile. We find that at least five galaxies can be classified as having pseudobulges. All ten galaxies lie below the M BH -L bulge relation, confirming earlier results. Their locus is similar to that occupied by pseudobulges. This leads us to conclude that the growth of BHs in NLS1s is governed by secular processes rather than merger-driven. Active galaxies in pseudobulges point to an alternative track of black hole-galaxy co-evolution. Because of the intrinsic scatter in black hole mass-bulge properties scaling relations caused by a combination of factors such as the galaxy morphology, orientation, and redshift evolution, application of scaling relations to determine BH masses may not be as straightforward as has been hoped.
We obtain high-precision limb-darkening measurements in five bands (V , V E , I E , I, and H) for the K3 III (T eff = 4200 K, [Fe/H]= +0.3, log g = 2.3) source of the Galactic bulge microlensing event EROS BLG-2000-5. These measurements are inconsistent with the predictions of atmospheric models at > 10 σ. While the disagreement is present in all bands, it is most apparent in I, I E and V E , in part because the data are better and in part because the intrinsic disagreement is stronger. We find that when limb-darkening profiles are normalized to have unit total flux, the I-band models for a broad range of temperatures all cross each other at a common point. The solar profile also passes through this point. However, the profile as measured by microlensing does not. We conjecture that the models have incorporated some aspect of solar physics that is not shared by giant atmospheres.
We present a study of outflow and feedback in the well-known Seyfert 2 galaxy Markarian 573 using high angular resolution long-slit spectrophotometry obtained with the Hubble Space Telescope Imaging Spectrograph (STIS). Through analysis of the kinematics and ionization state of a biconical outflow region emanating from the nucleus, we find that the outflow does not significantly accelerate the surrounding host-galaxy interstellar gas and is too weak to be a strong ionization mechanism in the extended emission regions. Instead, the excitation of the extended regions is consistent with photoionization by the active nucleus. From energetics arguments we show that the nuclear outflow is slow and heavy and has a mechanical luminosity that is only ∼1% of the estimated bolometric luminosity of the system. The energy in the outflow is able to mildly shape the gas in the extended regions but appears to be insufficient to unbind it, or even to plausibly disrupt star formation. These results are at odds with the picture of strong AGN feedback that has been invoked to explain certain aspects of galaxy evolution.
We present analysis and photoionization modeling of the Chandra high-resolution spectrum of Mrk 279. There is clear evidence of an absorbing outflow that is best fit by a two-component model: one with a low-ionization parameter and one with a higher ionization parameter. The column density of the X-ray warm absorber, about log N H ¼ 20, is the smallest known of all active galactic nuclei (AGNs) in which X-ray absorbing outflows are observed. We find that the X-ray and UV/ FUV absorbers are part of the same overall outflow. There is some evidence of supersolar carbon, nitrogen, oxygen, and iron in the Chandra spectrum of Mrk 279. While this is not a robust result in itself, Chandra data in combination with the UV data and the pressure equilibrium between two phases of the outflow, support the scenario of supersolar abundances. This is the first case in which supersolar abundances are reported in the nucleus of a normal Seyfert galaxy. The data suggest that the outflow originates from a compact region around the nuclear black hole and that it carries insignificant amounts of mass and energy.
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