- ID:
- ivo://CDS.VizieR/J/ApJ/788/159
- Title:
- 17 Seyfert 1 galaxies light curves
- Short Name:
- J/ApJ/788/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a dust reverberation survey for 17 nearby Seyfert 1 galaxies, which provides the largest homogeneous data collection for the radius of the innermost dust torus. A delayed response of the K-band light curve after the V-band light curve was found for all targets, and 49 measurements of lag times between the flux variation of the dust emission in the K band and that of the optical continuum emission in the V band were obtained by the cross-correlation function analysis and also by an alternative method for estimating the maximum likelihood lag. The lag times strongly correlated with the optical luminosity in the luminosity range of M_V_=-16 to -22 mag, and the regression analysis was performed to obtain the correlation log {Delta}t (days)=-2.11 -0.2 M_V_ assuming {Delta}t{prop.to}L^0.5^, which was theoretically expected. We discuss the possible origins of the intrinsic scatter of the dust lag-luminosity correlation, which was estimated to be approximately 0.13 dex, and we find that the difference of internal extinction and delayed response of changes in lag times to the flux variations could have partly contributed to intrinsic scatter. However, we could not detect any systematic change of the correlation with the subclass of the Seyfert type or the Eddington ratio. Finally, we compare the dust reverberation radius with the near-infrared interferometric radius of the dust torus and the reverberation radius of broad Balmer emission lines. The interferometric radius in the K band was found to be systematically larger than the dust reverberation radius in the same band by the about a factor of two, which could be interpreted by the difference between the flux-weighted radius and response-weighted radius of the innermost dust torus. The reverberation radius of the broad Balmer emission lines was found to be systematically smaller than the dust reverberation radius by about a factor of four to five, which strongly supports the unified scheme of the Seyfert type of active galactic nuclei (AGNs). Moreover, we examined the radius-luminosity correlations for the hard X-ray (14-195 keV) and the [O IV] {lambda}25.89 {mu}m emission-line luminosities, which would be applicable for obscured AGNs.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/106/399
- Title:
- Seyfert 2 galaxies multiwavelength catalog
- Short Name:
- J/ApJS/106/399
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is a catalog of Seyfert 2 galaxies observed in the 2-10keV band (339 flux entries). In total, it contains data on 150 objects; for 76 objects, a positive detection is reported, while for the remaining sources, 2{sigma} upper limits to the X-ray emission are given. Most of the data have been collected from the literature over a period starting from 1974 up to the middle of 1995. Accurate searches of literature and databases were performed for all objects, and frequently spectral fits were reevaluated in order to make the data in the catalog uniform and complete. Some unpublished data are also included. For six objects, EXOSAT/ME data have been extracted from the satellite database and analyzed; the 13 fluxes obtained have been added to the present catalog. The compilation of hard X-ray data has been complemented with data in the soft (0.1-3keV) X-ray band, as well as in ultraviolet (1450A), optical (5500A), infrared (3.5, 12, 25, 60, 100mm), and radio (6cm) bands. Fluxes of the [O III] {lambda}5007 and H{beta} emission lines as well as the Balmer decrement H{alpha}/H{beta}, and axial ratio a/b are also given. The present database is meant to be a useful tool for the study of the Seyfert 2 phenomenon in its various aspects.
- ID:
- ivo://CDS.VizieR/J/AJ/126/1750
- Title:
- Seyfert population in SSRS2
- Short Name:
- J/AJ/126/1750
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The magnitude-limited catalog of the Southern Sky Redshift Survey (SSRS2, Cat. <J/AJ/116/1>) is used to characterize the properties of galaxies hosting active galactic nuclei (AGNs). Using emission-line ratios, we identify a total of 162 (3%) Seyfert galaxies out of the parent sample with 5399 galaxies. The sample contains 121 Seyfert 2 galaxies and 41 Seyfert 1 galaxies. The SSRS2 Seyfert galaxies are predominantly in spirals of types Sb and earlier or in galaxies with perturbed appearance as the result of strong interactions or mergers. Seyfert galaxies in this sample are twice as common in barred hosts as the non-Seyfert galaxies. By assigning galaxies to groups using a percolation algorithm, we find that the Seyfert galaxies in the SSRS2 are more likely to be found in binary systems when compared with galaxies in the SSRS2 parent sample. However, there is no statistically significant difference between the Seyfert and SSRS2 parent sample when systems with more than two galaxies are considered. The analysis of the present sample suggests that there is a stronger correlation between the presence of the AGN phenomenon with internal properties of galaxies (morphology, presence of bar, luminosity) than with environmental effects (local galaxy density, group velocity dispersion, nearest neighbor distance).
- 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.
- 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/ApJS/172/599
- Title:
- SFI++ II. A new I-band Tully-Fisher catalog
- Short Name:
- J/ApJS/172/599
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the SFI++ data set, a homogeneously derived catalog of photometric and rotational properties and the Tully-Fisher distances and peculiar velocities derived from them. We make use of digital optical images, optical long-slit spectra, and global HI line profiles to extract parameters of relevance to disk scaling relations, incorporating several previously published data sets as well as a new photometric sample of some 2000 objects. According to the completeness of available redshift samples over the sky area, we exploit both a modified percolation algorithm and the Voronoi-Delaunay method to assign individual galaxies to groups as well as clusters, thereby reducing scatter introduced by local orbital motions. We also provide corrections to the peculiar velocities for both homogeneous and inhomogeneous Malmquist bias, making use of the 2MASS Redshift Survey density field to approximate large-scale structure. The final SFI++ peculiar velocity catalog contains 4861 field and cluster galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/701/1398
- Title:
- SFR for starburst galaxies
- Short Name:
- J/ApJ/701/1398
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comparison of star formation rates (SFR) determined from mid-infrared 7.7um polycyclic aromatic hydrocarbon (PAH) luminosity [SFR(PAH)], from 1.4GHz radio luminosity [SFR(radio)], and from far-ultraviolet luminosity [SFR(UV)] for a sample of 287 starburst galaxies with z<0.5 having Spitzer IRS observations.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/8
- Title:
- SFR for WISE + SDSS spectroscopic galaxies
- Short Name:
- J/ApJS/219/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine Sloan Digitital Sky Survey (SDSS) and WISE photometry for the full SDSS spectroscopic galaxy sample, creating spectral energy distributions (SEDs) that cover {lambda}=0.4-22{mu}m for an unprecedentedly large and comprehensive sample of 858365 present-epoch galaxies. Using MAGPHYS (da Cunha+ 2008MNRAS.388.1595D), we then simultaneously and consistently model both the attenuated stellar SED and the dust emission at 12 and 22{mu}m, producing robust new calibrations for monochromatic mid-IR star formation rate (SFR) proxies. These modeling results provide the first mid-IR-based view of the bimodality in star formation activity among galaxies, exhibiting the sequence of star-forming galaxies ("main sequence") with a slope of dlogSFR/dlogM_*_=0.80 and a scatter of 0.39dex. We find that these new SFRs along the SF main sequence are systematically lower by a factor of 1.4 than those derived from optical spectroscopy. We show that for most present-day galaxies, the 0.4-22{mu}m SED fits can exquisitely predict the fluxes measured by Herschel at much longer wavelengths. Our analysis also illustrates that the majority of stars in the present-day universe are formed in luminous galaxies (~L*) in and around the "green valley" of the color-luminosity plane. We make publicly available the matched photometry catalog and SED modeling results.
- ID:
- ivo://CDS.VizieR/J/ApJ/882/9
- Title:
- SFR & gas-phase metallicity in MaNGA gal.
- Short Name:
- J/ApJ/882/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The role of gas accretion in galaxy evolution is still a matter of debate. The presence of inflows of metal-poor gas that trigger star formation bursts of low metallicity has been proposed as an explanation for the local anticorrelation between star formation rate (SFR) and gas-phase metallicity (Z_g_) found in the literature. In the present study, we show how the anticorrelation is also present as part of a diversified range of behaviors for a sample of more than 700 nearby spiral galaxies from the SDSS-IV MaNGA survey. We have characterized the local relation between SFR and Z_g_ after subtracting the azimuthally averaged radial profiles of both quantities. Of the analyzed galaxies, 60% display an SFR-Z_g_ anticorrelation, with the remaining 40% showing no correlation (19%) or positive correlation (21%). Applying a random forest machine-learning algorithm, we find that the slope of the correlation is mainly determined by the average gas-phase metallicity of the galaxy. Galaxy mass, g-r colors, stellar age, and mass density seem to play a less significant role. This result is supported by the performed second-order polynomial regression analysis. Thus, the local SFR-Z_g_ slope varies with the average metallicity, with the more metal-poor galaxies presenting the lowest slopes (i.e., the strongest SFR-Z_g_ anticorrelations), and reversing the relation for more metal-rich systems. Our results suggest that external gas accretion fuels star formation in metal-poor galaxies, whereas in metal-rich systems, the gas comes from previous star formation episodes.
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/1332
- Title:
- SFR in galaxies at redshift z~0.8
- Short Name:
- J/MNRAS/454/1332
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the star formation history for a sample of 154 galaxies with stellar mass 10^10^<~M*<~10^12^M_{sun}_ in the redshift range 0.7<z<0.9. We do this using stellar population models combined with full-spectrum fitting of good quality spectra and high-resolution photometry. For a subset of 68 galaxies (M*>~10^11^M_{sun}_) we additionally construct dynamical models. These use an axisymmetric solution to the Jeans equations, which allows for velocity anisotropy, and adopts results from abundance matching techniques to account for the dark matter content. We find that (i) the trends in star formation history observed in the local Universe are already in place by z~1: the most massive galaxies are already passive, while lower mass ones have a more extended star formation histories, and the lowest mass galaxies are actively forming stars; (ii) we place an upper limit of a factor 1.5 to the size growth of the massive galaxy population; (iii) we present strong evidence for low dark matter fractions within 1Re (median of 9 per cent and 90th percentile of 21 per cent) for galaxies with M*>~10^11^M_{sun}_ at these redshifts; and (iv) we confirm that these galaxies have, on average, a Salpeter normalization of the stellar initial mass function.