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Supermassive black holes (SMBH) are believed to influence galaxy evolution through AGN (active galactic nuclei) feedback. Galaxy mergers are key processes of galaxy formation that lead to AGN activity and star formation. The relative contribution of AGN feedback and mergers to star formation is not yet well understood. In radio-loud objects, AGN outflows are dominated by large jets. However, in radio-quiet objects, outflows are more complex and involve jet, wind, and radiation. In this review, we discuss the signatures of AGN feedback through the alignment of radio and UV emissions. Current research on AGN feedback is discussed, along with a few examples of studies such as the galaxy merger system MRK 212, the radio-quiet AGN NGC 2639, and the radio-loud system Centaurus A. Multi-frequency observations of MRK 212 indicate the presence of dual AGN, as well as feedback-induced star-forming UV clumps. The fourth episode of AGN activity was detected in radio observations of the Seyfert galaxy NGC 2639, which also showed a central cavity of 6 kpc radius in CO and UV maps. This indicates that multi-epoch jets of radio-quiet AGN can blow out cold molecular gas, which can further reduce star formation in the center of the galaxies. Recent UV observations of Cen A have revealed two sets of stellar population in the northern star-forming region, which may have two different origins. Recent studies have shown that there is evidence that both positive and negative feedback can be present in galaxies at different scales and times. High-resolution, multi-band observations of large samples of different types of AGN and their host galaxies are important for understanding the two types of AGN feedback and their effect on the host galaxies. Future instruments like INSIST and UVEX will be able to help achieve some of these goals. [ABSTRACT FROM AUTHOR]

Supermassive black holes (SMBH) are believed to influence galaxy evolution through AGN (active galactic nuclei) feedback. Galaxy mergers are key processes of galaxy formation that lead to AGN activity and star formation. The relative contribution of AGN feedback and mergers to star formation is not yet well understood. In radio-loud objects, AGN outflows are dominated by large jets. However, in radio-quiet objects, outflows are more complex and involve jet, wind, and radiation. In this review, we discuss the signatures of AGN feedback through the alignment of radio and UV emissions. Current research on AGN feedback is discussed, along with a few examples of studies such as the galaxy merger system MRK 212, the radio-quiet AGN NGC 2639, and the radio-loud system Centaurus A. Multi-frequency observations of MRK 212 indicate the presence of dual AGN, as well as feedback-induced star-forming UV clumps. The fourth episode of AGN activity was detected in radio observations of the Seyfert galaxy NGC 2639, which also showed a central cavity of 6 kpc radius in CO and UV maps. This indicates that multi-epoch jets of radio-quiet AGN can blow out cold molecular gas, which can further reduce star formation in the center of the galaxies. Recent UV observations of Cen A have revealed two sets of stellar population in the northern star-forming region, which may have two different origins. Recent studies have shown that there is evidence that both positive and negative feedback can be present in galaxies at different scales and times. High-resolution, multi-band observations of large samples of different types of AGN and their host galaxies are important for understanding the two types of AGN feedback and their effect on the host galaxies. Future instruments like INSIST and UVEX will be able to help achieve some of these goals.

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In this paper, we investigate radio properties of active galaxies taken from the reference [Véron‐Cetty & Véron (2010)] catalog. The galaxies are limited to magnitudes in the range of 12m − 19m. We have cross‐correlated the list with radio catalogs and selected those galaxies that have data on six or more radio fluxes at different wavelengths. As a result, we have 198 galaxies that satisfy these conditions. Using SDSS DR15, we have obtained 96 spectroscopic identifications of the 198 objects. After the classification, 85% of the 96 objects have changed their types. Available data on the classification of these objects and our classification showed that 56.7% of them are Seyfert galaxies. For all the objects, we have built radio spectra and estimated radio spectral indices. As a result, we obtain α‾=−0.6089±0.056(α‾Seyfert=−0.6013±0.027, α‾LINER=−0.5955±0.025, α‾HII=−0.6672±0.039, α‾Comp.=−0.7128±0.043). We discuss the radio properties of active galaxies based on their radio spectral indices. [ABSTRACT FROM AUTHOR]

Several observations are revealing the widespread occurrence of mildly relativistic wide-angle AGN winds strongly interacting with the gas of their host galaxy. Such winds are potential cosmic-ray accelerators, as supported by gamma-ray observations of the nearby Seyfert galaxy NGC 1068 with the Fermi gamma-ray space telescope. The non-thermal emission produced by relativistic particles accelerated by the AGN-driven wind observed in the circum-nuclear molecular disk of such galaxy is invoked to produce the gamma-ray spectrum. The AGN wind model predicts a hard spectrum that extend in the very high energy band which differs significantly from those corresponding to other models discussed in the literature, like starburst or AGN jet. We present dedicated simulations of observations through the Cherenkov Telescope Array (CTA), the next-generation ground based gamma-ray observatory, of the very high energy spectrum of the Seyfert galaxy NGC 1068 assuming the AGN wind and the AGN jet models. We demonstrate that, considering 50 hours of observations, CTA can be effectively used to constrain the two different emission models, providing important insight into the physics governing the acceleration of particles in non-relativistic AGN-driven outflows. This analysis strongly motivates observations of Seyfert and starburst galaxies with CTA in order to test source population models of the extragalactic gamma-ray and neutrino backgrounds. [ABSTRACT FROM AUTHOR]

We investigated the interstellar medium (ISM) properties in the central regions of nearby Seyfert galaxies characterised by prominent conical or bi-conical outflows belonging to the MAGNUM survey by exploiting the unprecedented sensitivity, spatial and spectral coverage of the integral field spectrograph MUSE at the Very Large Telescope. We developed a novel approach based on the gas and stars kinematics to disentangle high-velocity gas in the outflow from gas in the disc to spatially track the differences in their ISM properties. This allowed us to reveal the presence of an ionisation structure within the extended outflows that can be interpreted with different photoionisation and shock conditions, and to trace tentative evidence of outflow-induced star formation ("positive" feedback) in a galaxy of the sample, Centaurus A. [ABSTRACT FROM AUTHOR]

We employ optical spectroscopy from the Multi Unit Spectroscopic Explorer (MUSE) combined with X-ray and radio data to study the highly-ionized gas (HIG) phase of the feedback in a sample of five local nearby Active Galactic Nuclei (AGN). Thanks to the superb field of view and sensitivity of MUSE, we found that the HIG, traced by the coronal line [Fe vii] λ6089, extends to scales not seen before, from 700 pc in Circinus and up to ∼2 kpc in NGC 5728 and NGC 3393. The gas morphology is complex, following closely the radio jet and the X-ray emission. Emission line ratios suggest gas excitation by shocks produced by the passage of the radio jet. This scenario is further supported by the physical conditions derived for the HIG, stressing the importance of the mechanical feedback in AGN with low-power radio jets. [ABSTRACT FROM AUTHOR]

We have obtained WFPC2 images of 256 of the nearest (z ≤ 0.035) Seyfert 1, Seyfert 2, and starburst galaxies. Our 500 s broadband (F606W) exposures reveal much fine-scale structure in the centers of these galaxies, including dust lanes and patches, bars, rings, wisps, and filaments, and tidal features such as warps and tails. Most of this fine structure cannot be detected in ground-based images. We have assigned qualitative classifications for these morphological features and a Hubble type for the inner region of each galaxy, and we have also measured quantitative information such as 0″.18 and 0″.92 aperture magnitudes, position angles, and ellipticities, where possible. There is little direct evidence for unusually high rates of interaction in the Seyfert galaxies. Slightly less than 10% of all the galaxies show tidal features or multiple nuclei. The incidence of inner starburst rings is about 10% in both classes of Seyfert galaxies. In contrast, galaxies with H II region emission-line spectra appear substantially more irregular and clumpy because of their much higher rates of current star formation per unit of galactic mass. The presence of an unresolved central continuum source in our Hubble Space Telescope images is a virtually perfect indicator of a Seyfert 1 nucleus as seen by ground-based spectroscopy. Fifty-two percent of these Seyfert 1 point sources are saturated in our images; we use their wings to estimate magnitudes ranging from 15.8 to 18.5. The converse is not universally true, however, as over one-third of Seyferts with direct spectroscopic evidence for broad Balmer wings show no nuclear point source. These 34 resolved Seyfert 1's have fainter nonstellar nuclei, which appear to be more extinguished by dust absorption. Like the Seyfert 2's, they have central surface brightnesses consistent with those expected for the bulges of normal galaxies. The rates for the occurrences of bars in Seyfert 1's and 2's and non-Seyferts are the same. We found one significant morphological difference between the host galaxies of Seyfert 1 and Seyfert 2 nuclei. The Seyfert 2 galaxies are significantly more likely to show nuclear dust absorption, especially in lanes and patches that are irregular or reach close to the nucleus. A few simple tests show that the difference cannot be explained by different average redshifts or selection techniques. It is confirmed by our galaxy morphology classifications, which show that Seyfert 1 nuclei reside in earlier type galaxies than Seyfert 2 nuclei. If, as we believe, this is an intrinsic difference in host galaxy properties, it undermines one of the postulates of the strong unification hypothesis for Seyfert galaxies, that they merely appear different because of the orientation of their central engine. The excess galactic dust we see in Seyfert 2's may cause substantial absorption that obscures their hypothesized broad emission line regions and central nonstellar continua. This galactic dust could produce much of the absorption in Seyfert 2 nuclei that had instead been attributed to a thick dusty accretion torus forming the outer part of the central engine.

We have obtained WFPC2 images of 256 of the nearest (z ≤ 0.035) Seyfert 1, Seyfert 2, and starburst galaxies. Our 500 s broadband (F606W) exposures reveal much fine-scale structure in the centers of these galaxies, including dust lanes and patches, bars, rings, wisps, and filaments, and tidal features such as warps and tails. Most of this fine structure cannot be detected in ground-based images. We have assigned qualitative classifications for these morphological features and a Hubble type for the inner region of each galaxy, and we have also measured quantitative information such as 0″.18 and 0″.92 aperture magnitudes, position angles, and ellipticities, where possible. There is little direct evidence for unusually high rates of interaction in the Seyfert galaxies. Slightly less than 10% of all the galaxies show tidal features or multiple nuclei. The incidence of inner starburst rings is about 10% in both classes of Seyfert galaxies. In contrast, galaxies with H II region emission-line spectra appear substantially more irregular and clumpy because of their much higher rates of current star formation per unit of galactic mass. The presence of an unresolved central continuum source in our Hubble Space Telescope images is a virtually perfect indicator of a Seyfert 1 nucleus as seen by ground-based spectroscopy. Fifty-two percent of these Seyfert 1 point sources are saturated in our images; we use their wings to estimate magnitudes ranging from 15.8 to 18.5. The converse is not universally true, however, as over one-third of Seyferts with direct spectroscopic evidence for broad Balmer wings show no nuclear point source. These 34 resolved Seyfert 1's have fainter nonstellar nuclei, which appear to be more extinguished by dust absorption. Like the Seyfert 2's, they have central surface brightnesses consistent with those expected for the bulges of normal galaxies. The rates for the occurrences of bars in Seyfert 1's and 2's and non-Seyferts are the same. We found one significant morphological difference between the host galaxies of Seyfert 1 and Seyfert 2 nuclei. The Seyfert 2 galaxies are significantly more likely to show nuclear dust absorption, especially in lanes and patches that are irregular or reach close to the nucleus. A few simple tests show that the difference cannot be explained by different average redshifts or selection techniques. It is confirmed by our galaxy morphology classifications, which show that Seyfert 1 nuclei reside in earlier type galaxies than Seyfert 2 nuclei. If, as we believe, this is an intrinsic difference in host galaxy properties, it undermines one of the postulates of the strong unification hypothesis for Seyfert galaxies, that they merely appear different because of the orientation of their central engine. The excess galactic dust we see in Seyfert 2's may cause substantial absorption that obscures their hypothesized broad emission line regions and central nonstellar continua. This galactic dust could produce much of the absorption in Seyfert 2 nuclei that had instead been attributed to a thick dusty accretion torus forming the outer part of the central engine.

An 8 month monitoring campaign on the Seyfert 1 galaxy Fairall 9 has been conducted with the International Ultraviolet Explorer in an attempt to obtain reliable estimates of continuum-continuum and continuum-emission-line delays for a high-luminosity active galactic nucleus (AGN). While the results of this campaign are more ambiguous than those of previous monitoring campaigns on lower luminosity sources, we find general agreement with the earlier results: (1) there is no measurable lag between ultraviolet continuum bands, and (2) the measured emission-line time lags are very short. It is especially notable that the Lyα + N v emission-line lag is about 1 order of magnitude smaller than determined from a previous campaign by Clavel, Wamsteker, & Glass (1989) when Fairall 9 was in a more luminous state. In other well-monitored sources, specifically NGC 5548 and NGC 3783, the highest ionization lines are found to respond to continuum variations more rapidly than the lower ionization lines, which suggests a radially ionization-stratified broad-line region. In this case, the results are less certain, since none of the emission-line lags are very well determined. The best-determined emission line lag is Lyα + N v, for which we find that the centroid of the continuum-emission-line cross-correlation function is τcent ≈ 14-20 days. We measure a lag τcent ≲ 4 days for He II λ1640; this result is consistent with the ionization-stratification pattern seen in lower luminosity sources, but the relatively large uncertainties in the emission-line lags measured here cannot rule out similar lags for Lyα + N v and He II λ1640 at a high level of significance. We are unable to determine a reliable lag for C IV λ1550, but we note that the profiles of the variable parts of Lyα and C IV λ1550 are not the same, which does not support the hypothesis that the strongest variations in these two lines arise in the same region.

We report the results of 20, 6, and 2 cm VLA and 1.5 cm OVRO observations of two similar radioquiet active galaxy and quasar (AGN) samples: the optically selected CfA Seyfert galaxies and the bolometric flux-limited 12 μm active galaxy sample. Every object observed was detected at 6 cm. Only ∼6%-8% of the 12 μm sample Seyfert galaxies (three to four objects) are radio-loud (and none of the CfA sample), as compared to 15%-20% for the Bright Quasar Survey quasars. These radio-loud objects are compact and have flat spectra, distinguishing them from the more common radio-quiet objects. The 6-20 cm slopes of the Seyfert 1's and 2's are similar, with average values of 〈α6cm20〉 = -0.66 and -0.71, respectively. Although several Seyfert 1's are significantly flatter than this in their 6-20 and/or 1.5-6 cm slopes, there is no systematic trend for either Seyfert type to display upward or downward spectral curvature. Excluding the radio-loud quasars, the integrated 6 cm radio luminosity is linearly proportional to the 60 μm luminosity over several orders of magnitude, with on average twice the radio power of normal spirals of the same far-infrared power. About half of the objects show extended 6 cm emission, contributing on average 33% of the total flux. Thus the luminosities of these extended components alone are comparable to normal spirals of similar infrared luminosities. The 12 μm sample radio luminosity function is slightly higher than that of the CfA sample. The integrated space density of Seyfert 2's is ∼2 times that of Seyfert 1's over their common range in luminosity. In terms of the standard unified model, this ratio in space density corresponds to a typical half-angle of the torus of θ ∼48°. © 1996. The American Astronomical Society. All rights reserved.

We present the results of ROSAT All-Sky Survey observations of Seyfert and IR luminous galaxies from the extended 12 μ galaxy sample and the optically selected CfA sample. Detections are available for 80% (44/55) of the Seyfert 1's and 34% (23/67) of the Seyfert 2's in the 12 μ sample, and for 76% (26/34) of the Seyfert 1's and 38% (6/16) of the Seyfert 2's in the CfA sample. Roughly half of the Seyfert galaxies (mostly Seyfert 1's) have been fitted to an absorbed power-law model, yielding an average photon index of F = 2.26 ± 0.11 for 43 Seyfert 1's and F = 2.45 ± 0.18 for 10 Seyfert 2's, with both types having a median value of 2.3. The soft X-ray luminosity correlates with the 12 μ luminosity, with Seyfert 1's having relatively more soft X-ray emission than Seyfert 2's of similar mid-IR luminosities by a factor of 1.6 ±0.3. Several physical interpretations of these results are discussed, including the standard unified model for Seyfert galaxies. Infrared luminous non-Seyferts are shown to have similar distributions of soft X-ray luminosity and X-ray-to-IR slope as Seyfert 2's, suggesting that some of them may harbor obscured active nuclei (as has already been shown to be true for several objects) and/or that the soft X-rays from some Seyferts 2's may be nonnuclear. A soft X-ray luminosity function (XLF) is calculated for the 12 μ sample, which is described well by a single power law with a slope of -1.75. The normalization of this XLF agrees well with that of a hard X-ray selected sample. Several of our results, related to the XLF and the X-ray-to-IR relation, are shown to be consistent with the hard X-ray observations of the 12 μ sample by Barcons et al. © 1996. The American Astronomical Society. All rights reserved.

We present and analyze ROSAT PSPC observations of eight Seyfert 2 galaxies, two Seyfert 1/QSOs, and one IR-luminous non-Seyfert galaxy. These targets were selected from the Extended 12 μm Galaxy Sample and, therefore, they have different multiwavelength properties from most (optically or X-ray-selected) Seyfert galaxies previously observed in the soft X-rays. The targets were also selected as having atypical X-ray fluxes among their respective classes, e.g., relatively X-ray-strong Seyfert 2s and X-ray-weak Seyfert 1/QSOs. Comparing our observations with those from the ROSAT All-Sky Survey, we find variability (of a factor of 1.5-2 in flux) in both the Seyfert 1/QSOs, but in none of the Seyfert 2s. Both variable objects have steeper photon indices in the more luminous state, with the softest (< 1.0 keV) flux varying the most. The timescales indicate that the variable component arises from a region less than a parsec in size. Fitting the spectra to an absorbed power-law model, we find that both the Seyfert 2s and the Seyfert 1/QSOs are best fit with a photon index of 3.1-3.2. This is in agreement with the average photon index of a sample of Markarian Seyfert 2s observed by Turner, Urry, & Mushotzky, indicating that most Seyfert 2s, even those displaying a wide variety multiwavelength of characteristics, as well as some Seyfert 1/QSOs, have a photon index much steeper than the canonical (Seyfert 1) value of ∼1.7. One possible explanation is that these objects have a flatter continuum plus a soft (< 1.0 keV) excess in the form of high-EW iron and/or oxygen fluorescence lines, a blackbody or even a thermal plasma. Alternatively, the underlying continuum may indeed be steep, powered by a different physical mechanism than that which produces the flat continua in other Seyfert 1/QSOs. We imaged one Seyfert 2 (NGC 5005) with the ROSAT HRI, finding about 13% of the soft X-rays to come from an extended source. This object also has the most evidence from spectral fitting for an extra contribution to the soft X-ray flux in addition to a power-law component, indicating that different components to the soft X-ray spectrum of this object (and likely of other X-ray-weak Seyfert galaxies) may come from spatially distinct regions. © 1996. The American Astronomical Society. All rights reserved.

We present the results of ROSAT All-Sky Survey observations of Seyfert and IR luminous galaxies from the extended 12 μ galaxy sample and the optically selected CfA sample. Detections are available for 80% (44/55) of the Seyfert 1's and 34% (23/67) of the Seyfert 2's in the 12 μ sample, and for 76% (26/34) of the Seyfert 1's and 38% (6/16) of the Seyfert 2's in the CfA sample. Roughly half of the Seyfert galaxies (mostly Seyfert 1's) have been fitted to an absorbed power-law model, yielding an average photon index of F = 2.26 ± 0.11 for 43 Seyfert 1's and F = 2.45 ± 0.18 for 10 Seyfert 2's, with both types having a median value of 2.3. The soft X-ray luminosity correlates with the 12 μ luminosity, with Seyfert 1's having relatively more soft X-ray emission than Seyfert 2's of similar mid-IR luminosities by a factor of 1.6 ±0.3. Several physical interpretations of these results are discussed, including the standard unified model for Seyfert galaxies. Infrared luminous non-Seyferts are shown to have similar distributions of soft X-ray luminosity and X-ray-to-IR slope as Seyfert 2's, suggesting that some of them may harbor obscured active nuclei (as has already been shown to be true for several objects) and/or that the soft X-rays from some Seyferts 2's may be nonnuclear. A soft X-ray luminosity function (XLF) is calculated for the 12 μ sample, which is described well by a single power law with a slope of -1.75. The normalization of this XLF agrees well with that of a hard X-ray selected sample. Several of our results, related to the XLF and the X-ray-to-IR relation, are shown to be consistent with the hard X-ray observations of the 12 μ sample by Barcons et al. © 1996. The American Astronomical Society. All rights reserved.

Aperture photometry from our own observations and the literature is presented for the 12 μm galaxies in the near-infrared J, H, and K bands and, in some cases, in the L band. These data are corrected to "total" near-infrared magnitudes (with a typical uncertainty of 0.3 mag) for a direct comparison with our IRAS fluxes which apply to the entire galaxy. The corrected data are used to derive integrated total near-infrared and far-infrared luminosities. We then combine these with blue photometry and an estimate of the flux contribution from cold dust at wavelengths longward of 100 μm to derive the first bolometric luminosities for a large sample of galaxies. The presence of nonstellar radiation at 2-3 μm correlates very well with nonstellar IRAS colors. This enables us to identify a universal Seyfert nuclear continuum from near- to far-infrared wavelengths. Thus, there is a sequence of infrared colors which runs from a pure "normal galaxy" to a pure Seyfert/quasar nucleus. Seyfert 2 galaxies fall close to this same sequence, although only a few extreme narrow-line Seyfert galaxies have quasar-like colors, and these show strong evidence of harboring an obscured broad-line region. A corollary is that the host galaxies of Seyfert nuclei have normal near- to far-infrared spectra on average. Starburst galaxies lie significantly off the sequence, having a relative excess of 60 μm emission probably as a result of stochastically heated dust grains. We use these correlations to identify several combinations of infrared colors which discriminate between Seyfert 1 and 2 galaxies, LINERs, and ultraluminous starbursts. In the infrared, Seyfert 2 galaxies are much more like Seyfert Is than they are like starbursts, presumably because both kinds of Seyferts are heated by a single central source, rather than a distributed region of star formation. Moreover, combining the [25-2.2 μm] color with the [60-12 μm] color, it appears that Seyfert 1 galaxies are segregated from Seyfert 2 galaxies and starburst galaxies in a well-defined region characterized by the hottest colors, corresponding to the flattest spectral slopes. Virtually no Seyfert 2 galaxy is present in such a region. To reconcile this with the "unified scheme" for Seyfert 1 and 2 galaxies would therefore require that the higher frequency radiation from the nuclei of Seyfert 2 galaxies to be absorbed by intervening dust and reemitted at lower frequencies. We find that bolometric luminosity is most closely proportional to 12 μm luminosity. The 60 and 25 μm luminosities rise faster than linearly with bolometric luminosity, while the optical flux rises less than linearly with bolometric luminosity. This result is a confirmation of the observation that more luminous disk galaxies have relatively more dust-enshrouded stars. Increases in the dust content shifts luminosity from the optical to 25-60 μm, while leaving a "pivot point" in the mid-IR essentially unchanged. Thus, 12 μm selection is the closest available approximation to selection by a limiting bolometric flux, which is approximately 14 times vLv at 12 μm for non-Seyfert galaxies. It follows that future deep surveys in the mid-infrared, at wavelengths of 8-12 μm, will simultaneously provide complete samples to different bolometric flux levels of normal and active galaxies, which will not suffer the strong selection effects present both in the optical-UV and far-infrared.

The discovery in 2008 of high-energy gamma-rays from Narrow-Line Seyfert 1 Galaxies (NLS1s) made it clear that there were active galactic nuclei (AGN) other than blazars and radio galaxies that can eject powerful relativistic jets. In addition to NLS1s, the great performance of the Fermi Large Area Telescope made it possible to discover MeV-GeV photons emitted from more classes of AGN, like Seyferts, Compact Steep Spectrum Gigahertz Peaked Sources (CSS/GPS), and disk-hosted radio galaxies. Although observations indicate a variety of objects, their physical characteristics point to a central engine powered by a relatively small-mass black hole (but, obviously, there are interpretations against this view). This essay critically reviews the literature published on these topics during the last eight years and analyzes the perspectives for the forthcoming years.

We have selected an all-sky (|b| ≥ 25°) 12 μm flux-limited sample of 893 galaxies from the IRAS Faint Source Catalog, Version 2 (FSC-2). This new sample contains 2.3 times as many objects as an earlier selection by Spinoglio & Malkan based on the IRAS Point Source Catalog, Version 2. We have obtained accurate total fluxes in the IRAS wavebands by using the ADDSCAN procedure for all objects with FSC-2 12 μm fluxes greater than 0.15 Jy and increasing flux densities from 12 to 60 μm, and denned the sample by imposing a survey limit of 0.22 Jy on the total 12 μm flux. Its completeness is verified, by means of the classical log N - log S and V/Vmax tests, down to 0.30 Jy, below which we have measured the incompleteness down to the survey limit, using the log N -log S plot, for our statistical analysis. We have obtained redshifts (mostly from catalogs) for virtually all (98.4%) the galaxies in the sample. Using existing catalogs of active galaxies, we defined a subsample of 118 objects consisting of 53 Seyfert 1s and quasars, 63 Seyfert 2s, and two blazars (∼13% of the full sample), which is the largest unbiased sample of Seyfert galaxies ever assembled. Since the 12 μm flux has been shown to be about one-fifth of the bolometric flux for Seyfert galaxies and quasars, the subsample of Seyferts (including quasars and blazars) is complete not only to 0.30 Jy at 12 μm but also with respect to a bolometric flux limit of ∼2.0 × 10-10 ergs s-1 cm-2. The average value of V/Vmax for the full sample, corrected for incompleteness at low fluxes, is 0.51 ± 0.04, expected for a complete sample of uniformly distributed galaxies, while the value for the Seyfert galaxy subsample is 0.46 ± 0.10, suggesting that several of the more distant galaxies remain to be identified as Seyferts in our sample. We have derived 12 μm and far-infrared luminosity functions for the AGNs, as well as for the entire sample. The AGN luminosity functions are more complete than those of the optically selected CfA Seyfert galaxies for all luminosities and AGN types. We extracted from our sample a complete subsample of 235 galaxies flux-limited (8.3 Jy) at 60 μm. The 60 μm luminosity function computed for this subsample is in satisfactory agreement with the ones derived from the bright galaxy sample (BGS) and the deep high-galactic latitude sample, both selected at 60 μm. Over the high-luminosity range where our sample and the BGS overlap, however, our space densities are systematically lower by a factor of ∼1.5, whereas at low luminosities our space densities are higher by about the same amount. Comparable results are obtained when comparing the far-IR luminosity function of our entire sample with the one derived from the BGS. This is not unexpected, because of the bias toward high-luminosity spirals caused by selection at 60 μm.

Observations performed at Metsähovi Radio Observatory at 37 GHz are presented for a sample of 78 radio-loud and radio-quiet narrow-line Seyfert 1 (NLS1) galaxies, together with additional lower and higher frequency radio data from RATAN-600, Owens Valley Radio Observatory and the Planck satellite. Most of the data have been gathered between February 2012 and April 2015 but for some sources even longer light curves exist. The detection rate at 37 GHz is around 19%, which is comparable to other populations of active galactic nuclei presumed to be faint at radio frequencies, such as BL Lac objects. Variability and spectral indices are determined for sources with enough detections. Based on the radio data, many NLS1 galaxies show a blazar-like radio spectra exhibiting significant variability. The spectra at a given time are often inverted or convex. The source of the high-frequency radio emission in NLS1 galaxies, detected at 37 GHz, is most probably a relativistic jet rather than star formation. Jets in NLS1 galaxies are therefore expected to be a much more common phenomenon than earlier assumed. [ABSTRACT FROM AUTHOR]

We combine the Herschel Space Observatory PACS (Photoconductor Array Camera and Spectrometer) and SPIRE (Spectral and Photometric Imaging Receiver) photometry with archival WISE (Wide-field Infrared Survey Explorer) photometry to construct the spectral energy distributions (SEDs) for over 300 local (z < 0.05), ultrahard X-ray (14-195 keV) selected active galactic nuclei (AGN) from the Swift Burst Alert Telescope (BAT) 58-month catalogue. Using a simple analytical model that combines an exponentially cutoff power law with a single temperature modified blackbody, we decompose the SEDs into a host galaxy and AGN component. We calculate dust masses, dust temperatures, and star formation rates (SFRs) for our entire sample and compare them to a stellar mass-matched sample of local non-AGN galaxies. We find AGN host galaxies have systematically higher dust masses, dust temperatures, and SFRs due to the higher prevalence of late-type galaxies to host an AGN, in agreement with previous studies of the Swift/BAT AGN. We provide a scaling to convert X-ray luminosities into 8-1000 μmAGN luminosities, as well as determine the bestmid-to-far IR colours for identifying AGN-dominated galaxies in the IR regime. We find that for nearly 30 per cent of our sample, the 70 μm emission contains a significant contribution from theAGN (>0.5), especially at higher luminosities (L14-195 keV > 1042.5 erg s-1). Finally, we measure the local SFR-AGN luminosity relationship, finding a slope of 0.18, large scatter (0.37 dex), and no evidence for an upturn at high AGN luminosity. We conclude with a discussion on the implications of our results within the context of galaxy evolution with and without AGN feedback. [ABSTRACT FROM AUTHOR]

We present preliminary results of the long-term spectral monitoring of two active galactic nuclei with different broad line shapes: Ark 564 and Arp 102B. Ark 564 is a bright nearby narrow-line Syfert 1 (NLS1) galaxy with relatively narrow permitted optical emission lines and a high Fe II/Hβ ratio, while Arp 102B is a nearby broad-line radio galaxy with broad double-peaked Balmer emission lines. The spectra of Ark 564 were observed during 11-year period (1999-2009) and the spectra of Arp 102B in the 12-year period (1998-2009), with SAO 6 m and 1 m telescopes (Russia) and the OAGH 2.1 m telescope (Cananea, Mexico).

We report the preliminary results of a kinematical study of three Seyfert galaxies selected from a sample of nearby active galactic nuclei observed using 3D spectroscopy. The observations were performed at the prime focus of the 6 m telescope of SAO RAS with the integral-field spectrograph MPFS and with a scanning Fabry-Pérot interferometer, installed on the multimode device SCORPIO. Based on these data, the monochromatic maps and velocity fields in different emission lines were constructed. We have detected the nuclear outflow or ionized gas motions associated with a radio jet in all the circumnuclear regions of these galaxies.

The general picture of how thermal AGNs work has become clearer in recent years but major observational puzzles threaten to undermine this picture. These puzzles include AGNs with extremely asymmetric emission line profiles, inconsistent multi-wavelength variability, rapid apparent changes in the sizes of emitting regions and in the direction of gas flow, a curious insensitivity of gas in some narrow velocity ranges to changes in the ionizing continuum, and differing dependences of polarization on gas velocity. It is proposed that all these puzzles can readily be explained by off-axis variability.

We test the consistency of active galactic nuclei (AGN) optical flux variability with the damped random walk (DRW) model. Our sample consists of 20 multiquarter Kepler AGN light curves including both Type 1 and 2 Seyferts, radio-loud and -quiet AGN, quasars, and blazars. Kepler observations of AGN light curves offer a unique insight into the variability properties of AGN light curves because of the very rapid (11.6-28.6 min) and highly uniform rest-frame sampling combined with a photometric precision of 1 part in 105 over a period of 3.5 yr. We categorize the light curves of all 20 objects based on visual similarities and find that the light curves fall into five broad categories. We measure the first-order structure function of these light curves and model the observed light curve with a general broken power-law power spectral density (PSD) characterized by a short-time-scale power-law index γ and turnover time-scale τ. We find that less than half the objects are consistent with a DRW and observe variability on short time-scales (~2 h). The turnover time-scale τ ranges from ~10-135 d. Interesting structure function features include pronounced dips on rest-frame time-scales ranging from 10-100 d and varying slopes on different time-scales. The range of observed short-time-scale PSD slopes and the presence of dip and varying slope features suggests that the DRW model may not be appropriate for all AGN. We conclude that AGN variability is a complex phenomenon that requires a more sophisticated statistical treatment. [ABSTRACT FROM AUTHOR]

We present the first of a series of studies of the evolution of galaxies in compact groups over the past 3 Gyr. This article focuses on the evolution of nuclear activity and how it has been affected by the dense environment of the groups. Our analysis is based on the largest multiwavelength compact-group sample to date, containing complete ultraviolet-infrared (UV-IR) photometry for 1770 isolated groups (7417 galaxies). We classified the nuclear activity of the galaxies based on optical emission-line and mid-infrared (mid-IR) diagnostic methods, as well as using spectral energy distribution fitting. We observe a 15 per cent increase in the number of active galactic nucleus (AGN)-hosting late-type galaxies found in dynamically old groups over the past 3 Gyr, accompanied by a corresponding decrease in their circumnuclear star formation. Comparing our compact group results with those for local isolated field and interacting pair galaxies, we find no differences in the AGNs at the same redshift range. Based on both optical and mid-IR colour classifications, we report the absence of Seyfert 1 nuclei and attribute this to the low accretion rates caused by depletion of gas. We propose that the observed increase in low-ionization nuclear emission-line regions (LINERs) and Seyfert 2 nuclei (at low z) in early-type galaxies of dynamically young groups is due to the morphological transformation of lenticular galaxies into elliptical ones. Finally, we show that, at any given stellar mass, galaxies found in dynamically old groups are more likely to host an AGN. Our findings suggest that depletion of gas due to past star formation and tidal stripping is the major mechanism driving the evolution of nuclear activity in compact groups of galaxies. [ABSTRACT FROM AUTHOR]

Obscured active galactic nuclei (AGNs) provide an opportunity to study the material surrounding the central engine. Geometric and physical constraints on the absorber can be deduced from the reprocessed AGN emission. In particular, the obscuring gas may reprocess the nuclear X-ray emission producing a narrow Fe Kα line and a Compton reflection hump. In recent years, models of the X-ray reflection from an obscuring torus have been computed; however, although the reflecting gas may be dusty, the models do not yet take into account the effects of dust on the predicted spectrum. We study this problem by analysing two sets of models, with and without the presence of dust, using the one-dimensional photoionization code CLOUDY. The calculations are performed for a range of column densities (22 < log[NH(cm-2)] < 24.5) and hydrogen densities (6 < log[nH(cm-3)] < 8). The calculations show the presence of dust can enhance the Fe Kα equivalent width (EW) in the reflected spectrum by factors up to ≈8 for Compton thick (CT) gas and a typical interstellar medium grain size distribution. The enhancement in EW with respect to the reflection continuum is due to the reduction in the reflected continuum intensity caused by the anisotropic scattering behaviour of dust grains. This effect will be most relevant for reflection from distant, predominately neutral gas, and is a possible explanation for AGNs which show a strong Fe Kα EW and a relatively weak reflection continuum. Our results show it is an important to take into account dust while modelling the X-ray reflection spectrum, and that inferring a CT column density from an observed Fe Kα EW may not always be valid. Multidimensional models are needed to fully explore the magnitude of the effect. [ABSTRACT FROM AUTHOR]

Mrk 1388 has an unusual Seyfert nucleus that shows narrow emission-line components without broad emission-line ones, but shows a strong featureless continuum and strong iron-forbidden, high-ionization emission lines. The apparent coexistence of type-1/2 characteristics is potentially attributed to a heavily obscured broad-line region or to an intermediate-mass black hole with a broad-line component that is intrinsically narrower than those of typical narrow-line Seyfert 1 (NLS1) galaxies. Our observation carried out by using very-long-baseline interferometry (VLBI) reveals high-brightness radio emission in nonthermal jets emerging from an active galactic nucleus (AGN) with a significant radio luminosity. Furthermore, we investigate the radial profile of the host galaxy using a Hubble Space Telescope (HST) image, which shows a Sérsic index suggestive of a pseudobulge. Using the VLBI and HST results which essentially are not affected by dust extinction, we apply the three individual methods to an estimate of the black hole mass and obtain three similar ones: (0.76-5.4) x 106 M⊙, 1.5 x 106 M⊙,and 4.1 x 106 M⊙. These masses are within a range that is fitted with typical NLS1 galaxies rather than with intermediate-mass black holes. Based on the estimated masses, a full width at half maximum FWHM(Hβ) of approximately 1200-1700 km s-1 should have been seen. The scenario in a heavily absorbed NLS1 nucleus can explain the peculiarities previously observed. [ABSTRACT FROM AUTHOR]

The maximum likelihood estimator is used to determine fit parameters for various parametric models of the Fourier periodogram followed by the selection of the best-fit model amongst competing models using the Akaike information criteria. This analysis, when applied to light curves of active galactic nuclei can be used to infer the presence of quasi-periodicity and break or knee frequencies. The extracted information can be used to place constraints on the mass, spin and other properties of the putative central black hole and the region surrounding it through theoretical models involving disk and jet physics. [ABSTRACT FROM AUTHOR]

We present estimates of black hole accretion rates (BHARs) and nuclear, extended, and total star formation rates tbr a complete sample of Seyfert galaxies. Using data from the Spitzer Space Telescope, we measure the active galactic nucleus (AGN) luminosity using the [O IV] λ25.89 µm emission line and the star-forming luminosity using the 11.3 μm aromatic feature and extended 24 μm continuum emission. We find that black hole growth is strongly correlated with nuclear (r < 1 kpc) star formation, but only weakly correlated with extended (r > 1 kpc) star formation in the host galaxy. In particular, the nuclear star formation rate (SFR) traced by the 11.3 Itm aromatic feature follows a relationship with the BHAR of the form SFR α M0.8BH, with an observed scatter of 0.5 dex. This SFR-BHAR relationship persists when additional star formation in physically matched r = 1 kpc apertures is included, taking the form SFR α M0.6BH. However, the relationship becomes almost indiscernible when total SFRs are considered. This suggests a physical connection between the gas on sub-kiloparsec and sub-parsec scales in local Seyfert galaxies that is not related to external processes in the host galaxy. It also suggests that the observed scaling between star formation and black hole growth for samples of AGNs will depend on whether the star tormation is dominated by a nuclear or an extended component. We estimate the integrated black hole and bulge growth that occurs in these galaxies and find that an AGN duty cycle of 5%-10% would maintain the ratio between black hole and bulge masses seen in the local universe. [ABSTRACT FROM AUTHOR]

We present CO(3-2) intefferometric observations of the central region of the Seyfert 2 galaxy NGC 1068 using the Submillimeter Array, together with CO(1-0) data taken with the Owens Valley Radio Observatory Millimeter Array. Both the CO(3-2) and CO(1-0) emission lines are mainly distributed within ~5 arcsec of the nucleus and along the spiral arms, but the intensity distributions show differences: the CO(3-2) map peaks in the nucleus, while the CO(1-0) emission is mainly located along the spiral arms. The CO(3-2)/CO(1-0) ratio is about 3.1 in the nucleus, which is four times as large as the average line ratio in the spiral arms, suggesting that the molecular gas there must be affected by the radiation arising from the active galactic nucleus. On the other hand, the line ratios in the spiral arms vary over a wide range from 0.24 to 2.34 with an average value around 0.75, which is similar to the line ratios of star formation regions, indicating that the molecular gas is affected by star formation. Besides, we see a tight correlation between CO(3-2)/(1-0) ratios in the spiral arms and star formation rate surface densities derived from Spitzer 8 μm dust flux densities. We also compare the CO(3-2)/(1-0) ratio and the star formation rate at different positions within the spiral arms; both are found to decrease as the radius from the nucleus increases. [ABSTRACT FROM AUTHOR]

Since its launch on October 2002, the INTEGRAL satellite has revolutionized our knowledge of the hard X–ray sky thanks to its unprecedented imaging capabilities and source detection positional accuracy above 20 keV. Nevertheless, many of the newly-detected sources in the INTEGRAL sky surveys are of unknown nature. However, the combined use of available information at longer wavelengths (mainly soft X–rays and radio) and of optical spectroscopy on the putative counterparts of these new hard X–ray objects allows pinpointing their exact nature. Continuing our long-standing program running since 2004 (and with which we identified more than 100 INTEGRAL objects) here we report the classification, through optical spectroscopy, of 25 unidentified high-energy sources, mostly belonging to the recently published 4-th IBIS survey. [ABSTRACT FROM AUTHOR]

The ROSAT source 1RXS J181333.7+453118 is a Seyfert Sy1 galaxy with a red shift of z=0.093. A ROSAT spectrum and a spectrum over wavelengths of λ4500-7250Å taken with the 2.6-m telescope at the Byurakan Astrophysical Observatory are shown. The x-ray spectrum has characteristics similar to an AGN with a soft x-ray excess. [ABSTRACT FROM AUTHOR]

We present results of multi-epoch XMM-Newton observations separated by several years of the narrow-line Seyfert 1 (NLS1) galaxy, SDSS J160508.87+323921.4. The NLS1 showed X-ray flux variations on timescales of years as well as low amplitude variations on timescales as short as hours, while the X-ray spectral shape remained essentially unchanged. The spectrum shows a significant soft X-ray excess. The model of reflection from an ionized disc, that is dominant in the whole XMM-Newton bandpass, provides the best description of the observed spectra for all the observations, though alternatives such as Compton scattering ( T ∼ 0.25 keV) cannot be ruled out in a statistical sense. For the disc reflection model, the observed variations may originate either from the change in the reflection fraction, or from the variability of the intrinsic X-ray luminosity. [ABSTRACT FROM AUTHOR]