- ID:
- ivo://CDS.VizieR/J/A+A/335/912
- Title:
- Seyferts in galaxy pairs and groups
- Short Name:
- J/A+A/335/912
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The occurrence of Seyfert galaxies in 6 samples representative of different cosmological environments (i.e. isolated pairs, compact and loose groups) is analysed. To avoid biases linked to subjective sample selection criteria only canonical samples, taken from the literature, are considered. It is found that the average frequency of Seyferts in all samples, is near 2%. Most Seyferts lying in pairs and compact groups show disturbed morphological appearance, whilst in loose groups disturbed and ``isolated'' Seyferts have roughly the same proportion. Then, within each sample, structures which host a Seyfert are compared to structures which do not. No appreciable differences regarding dynamical properties are found.
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- ID:
- ivo://CDS.VizieR/J/A+A/643/A127
- Title:
- 5 Seyferts reduced CO(2-1) cubes
- Short Name:
- J/A+A/643/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Active galactic nucleus (AGN) driven outflows are believed to play an important role in regulating the growth of galaxies, mostly via negative feedback. However, their effects on their hosts are far from clear, especially for low- and moderate-luminosity Seyferts. To investigate this issue, we obtained cold molecular gas observations, traced by the CO(2-1) transition, using the NOEMA interferometer of five nearby (distances between 19 and 58Mpc) Seyfert galaxies. The resolution of ~0.3-0.8 (~30-100pc) and field of view of NOEMA allowed us to study the CO(2-1) morphology and kinematics in the nuclear regions (~100pc) and up to radial distances of ~900pc. We detected CO(2-1) emission in all five galaxies with disky or circumnuclear ring-like morphologies. We derived cold molecular gas masses on nuclear (~100pc) and circumnuclear (~650pc) scales in the range from 10^6^ to 10^7^M_{sun}_ and from 10^7^ to 10^8^M_{sun}_, respectively. In all of our galaxies, the bulk of this gas is rotating in the plane of the galaxy. However, noncircular motions are also present. In NGC 4253, NGC 4388, and NGC 7465, we can ascribe the streaming motions to the presence of a large-scale bar. In Mrk 1066 and NGC 4388, the noncircular motions in the nuclear regions are explained as outflowing material due to the interaction of the AGN wind with molecular gas in the galaxy disk. We conclude that for an unambiguous and precise interpretation of the kinematics of the cold molecular gas, we need detailed knowledge of the host galaxy (i.e., presence of bars, interactions, etc.), and also of the ionized gas kinematics and ionization cone geometry.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A128
- Title:
- SINFONI datacube of NGC 1365
- Short Name:
- J/A+A/622/A128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the framework of understanding the gas and stellar kinematics and their relations to AGNs and galaxy evolution scenarios, we present spatially resolved distributions and kinematics of the stars and gas in the central ~800-pc radius of the nearby Seyfert galaxy NGC 1365. We obtained H + K- and K-band near-infrared (NIR) integral-field observations from VLT/SINFONI. Our results reveal strong broad and narrow emission-line components of ionized gas (hydrogen recombination lines Pa{alpha} and Br{gamma}) in the nuclear region, as well as hot dust with a temperature of ~1300K, both typical for type-1 AGNs. From M_BH_-{sigma}* and the broad components of hydrogen recombination lines, we find a black-hole mass of (5-10)x10^6^M_{sun}_. In the central ~800pc, we find a hot molecular gas mass of ~615M , which corresponds to a cold molecular gas reservoir of (2-8)x10^8^M_{sun}_. However, there is a molecular gas deficiency in the nuclear region. The gas and stellar-velocity maps both show rotation patterns consistent with the large-scale rotation of the galaxy. However, the gaseous and stellar kinematics show deviations from pure disk rotation, which suggest streaming motions in the central <200pc and a velocity twist at the location of the ring which indicates deviations in disk and ring rotation velocities in accordance with published CO kinematics. We detect a blueshifted emission line split in Pa{alpha}, associated with the nuclear region only. We investigate the star-formation properties of the hot spots in the circumnuclear ring which have starburst ages of 10Myr and find indications for an age gradient on the western side of the ring. In addition, our high-resolution data reveal further substructure within this ring which also shows enhanced star forming activity close to the nucleus.
- ID:
- ivo://CDS.VizieR/J/ApJS/217/12
- Title:
- S7 observations with WiFeS of active galaxies
- Short Name:
- J/ApJS/217/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph (WiFeS) mounted on the ANU 2.3m telescope located at the Siding Spring Observatory to deliver an integral field of 38x25 arcsec at a spectral resolution of R=7000 in the red (530-710nm), and R=3000 in the blue (340-560nm). From these data cubes we have extracted the narrow-line region spectra from a 4 arcsec aperture centered on the nucleus. We also determine the H{beta} and [OIII]{lambda}5007 fluxes in the narrow lines, the nuclear reddening, the reddening-corrected relative intensities of the observed emission lines, and the H{beta} and [OIII]{lambda}5007 luminosities determined from spectra for which the stellar continuum has been removed. We present a set of images of the galaxies in [OIII]{lambda}5007, [NII]{lambda}6584, and H{alpha}, which serve to delineate the spatial extent of the extended narrow-line region and also to reveal the structure and morphology of the surrounding HII regions. Finally, we provide a preliminary discussion of those Seyfert 1 and Seyfert 2 galaxies that display coronal emission lines in order to explore the origin of these lines.
- ID:
- ivo://CDS.VizieR/J/A+A/368/797
- Title:
- Soft X-ray properties of Seyfert galaxies
- Short Name:
- J/A+A/368/797
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of ROSAT detected sources in the sample of spectroscopically selected Seyfert 1 and Seyfert 2 galaxies of Rafanelli et al. (1995AJ....109.1546R). The catalogue contains 102 Seyfert 1 and 36 Seyfert 2 galaxies. The identification is based on X-ray contour maps overlaid on optical images taken from the Digitized Sky Survey. We have derived the basic spectral and timing properties of the X-ray detected Seyfert galaxies. For Seyfert 1 galaxies a strong correlation between photon index and X-ray luminosity is detected. We confirm the presence of generally steeper X-ray continua in narrow-line Seyfert 1 galaxies (NLS1s) compared to broad-line Seyfert 1 galaxies. Seyfert 2 galaxies show photon indices similar to those of NLS1s. Whereas a tendency for an increasing X-ray luminosity with increasing interaction strength is found for Seyfert 1 galaxies, such a correlation is not found for Seyfert 2 galaxies. For Seyfert 1 galaxies we found also a strong correlation for increasing far-infrared luminosity with increasing interaction strength. Both NLS1s and Seyfert 2 galaxies show the highest values of far-infrared luminosity compared to Seyfert 1 galaxies, suggesting that NLS1s and Seyfert 2 galaxies host strong (circumnuclear) star formation. For variable Seyfert galaxies we present the X-ray light curves obtained from the ROSAT All-Sky Survey and from ROSAT PSPC and HRI pointed observations. Besides the expected strong short- and long-term X-ray variability in Seyfert 1 galaxies, we find indications for X-ray flux variations in Seyfert 2 galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/112/315
- Title:
- Spectroscopic parameters of Seyfert nuclei
- Short Name:
- J/ApJS/112/315
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have completed an optical spectroscopic survey of the nuclear regions (r<=200pc) of a large sample of nearby galaxies. Although the main objectives of the survey are to search for low-luminosity active galactic nuclei and to quantify their luminosity function, the database can be used for a variety of other purposes. This paper presents measurements of the spectroscopic parameters for the 418 emission-line nuclei, along with a compilation of the global properties of all 486 galaxies in the survey. Stellar absorption generally poses a serious obstacle to obtaining accurate measurement of emission lines in nearby galactic nuclei. We describe a procedure for removing the starlight from the observed spectra in an efficient and objective manner. The main parameters of the emission lines (intensity ratios, fluxes, profile widths, and equivalent widths) are measured and tabulated, as are several stellar absorption-line and continuum indices useful for studying the stellar population. Using standard nebular diagnostics, we determine the probable ionization mechanisms of the emission-line objects. The resulting spectral classifications provide extensive information on the demographics of emission-line nuclei in the nearby regions of the universe. This new catalog contains over 200 objects showing spectroscopic evidence for recent star formation and an equally large number of active galactic nuclei, including 46 that show broad H{alpha} emission. These samples will serve as the basis of future studies of nuclear activity in nearby galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/439/1648
- Title:
- Subarcsecond mid-infrared atlas of local AGN
- Short Name:
- J/MNRAS/439/1648
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first subarcsecond-resolution mid-infrared (MIR) atlas of local active galactic nuclei (AGN). Our atlas contains 253 AGN with a median redshift of z=0.016, and includes all publicly available MIR imaging performed to date with ground-based 8-m class telescopes, a total of 895 independent measurements. Of these, more than 60% are published here for the first time. We detect extended nuclear emission in at least 21% of the objects, while another 19% appear clearly point-like, and the remaining objects cannot be constrained. Where present, elongated nuclear emission aligns with the ionization cones in Seyferts. Subarcsecond resolution allows us to isolate the AGN emission on scales of a few tens of parsecs and to obtain nuclear photometry in multiple filters for the objects. Median spectral energy distributions (SEDs) for the different optical AGN types are constructed and individual MIR 12 and 18um continuum luminosities are computed. These range over more than six orders of magnitude. In comparison to the arcsecond-scale MIR emission as probed by Spitzer, the continuum emission is much lower on subarcsecond scales in many cases. The silicate feature strength is similar on both scales and generally appears in emission (absorption) in type I (II) AGN. However, the polycyclic aromatic hydrocarbon emission appears weaker or absent on subarcsecond scales. The differences of the MIR SEDs on both scales are particularly large for AGN/starburst composites and close-by (and weak) AGN. The nucleus dominates over the total emission of the galaxy only at luminosities >~10^44^erg/s. The AGN MIR atlas is well suited not only for detailed investigation of individual sources but also for statistical studies of AGN unification.
- ID:
- ivo://CDS.VizieR/J/ApJ/870/123
- Title:
- Swift optical & UV flux of four AGNs
- Short Name:
- J/ApJ/870/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Swift intensive accretion disk reverberation mapping of four AGN yielded light curves sampled ~200-350 times in 0.3-10keV X-ray and six UV/optical bands. Uniform reduction and cross-correlation analysis of these data sets yields three main results: (1) The X-ray/UV correlations are much weaker than those within the UV/optical, posing severe problems for the lamp-post reprocessing model in which variations in a central X-ray corona drive and power those in the surrounding accretion disk. (2) The UV/optical interband lags are generally consistent with {tau}{propto}{lambda}^4/3^ as predicted by the centrally illuminated thin accretion disk model. While the average interband lags are somewhat larger than predicted, these results alone are not inconsistent with the thin disk model given the large systematic uncertainties involved. (3) The one exception is the U band lags, which are on average a factor of ~2.2 larger than predicted from the surrounding band data and fits. This excess appears to be due to diffuse continuum emission from the broad-line region (BLR). The precise mixing of disk and BLR components cannot be determined from these data alone. The lags in different AGN appear to scale with mass or luminosity. We also find that there are systematic differences between the uncertainties derived by Just Another Vehicle for Estimating Lags In Nuclei (JAVELIN) versus more standard lag measurement techniques, with JAVELIN reporting smaller uncertainties by a factor of 2.5 on average. In order to be conservative only standard techniques were used in the analyses reported herein.
- ID:
- ivo://CDS.VizieR/VII/157
- Title:
- The Extended 12um galaxy sample
- Short Name:
- VII/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The authors have used the IRAS data to compile a sample of 893 galaxies, including 118 Seyfert galaxies. Please refer to the "12micron.doc" (ascii) or "12micron.tex" (LaTeX) file for complete descriptions.
- ID:
- ivo://CDS.VizieR/J/AJ/160/242
- Title:
- The H{alpha} dots survey. II. 119 new dots
- Short Name:
- J/AJ/160/242
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- We present the second catalog of serendipitously discovered compact extragalactic emission-line sources-H{alpha} Dots. These objects have been discovered in searches of moderately deep narrow-band images acquired for the ALFALFA H{alpha} project. In addition to cataloging 119 new H{alpha} Dots, we also present follow-up spectral data for the full sample. These spectra allow us to confirm the nature of these objects as true extragalactic emission-line objects, to classify them in terms of activity type (star-forming or AGN), and to identify the emission line via which they were discovered. We tabulate photometric and spectroscopic data for the all objects, and we present an overview of the properties of the full H{alpha} Dot sample. The H{alpha} Dots represent a broad range of star-forming and active galaxies detected via several different emission lines over a wide range of redshifts. The sample includes H{alpha}-detected blue compact dwarf galaxies at low redshift, [OIII]-detected Seyfert 2 and Green Pea-like galaxies at intermediate redshifts, and QSOs detected via one of several UV emission lines, including Ly{alpha}. Despite the heterogeneous appearance of the resulting catalog of objects, we show that our selection method leads to well-defined samples of specific classes of emission-line objects with properties that allow for statistical studies of each class.
