- ID:
- ivo://CDS.VizieR/J/ApJS/229/39
- Title:
- Narrow line Seyfert 1 galaxies from SDSS-DR12
- Short Name:
- J/ApJS/229/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalog of narrow-line Seyfert 1 (NLSy1) galaxies from the Sloan Digital Sky Survey Data Release 12 (SDSS DR12). This was obtained by a systematic analysis through modeling of the continuum and emission lines of the spectra of all the 68859 SDSS-DR12 objects that are classified as "QSO" by the SDSS spectroscopic pipeline with z<0.8 and a median signal-to-noise ratio (S/N)>2/pixel. This catalog contains a total of 11101 objects, which is about 5 times larger than the previously known NLSy1 galaxies. Their monochromatic continuum luminosity at 5100{AA} is found to be strongly correlated with H{beta}, H{alpha}, and [OIII] emission line luminosities. The optical FeII strength in NLSy1 galaxies is about two times larger than the broad-line Seyfert 1 (BLSy1) galaxies. About 5% of the catalog sources are detected in the FIRST survey. The Eddington ratio ({xi}_Edd_) of NLSy1 galaxies has an average of log({xi}_Edd_) of -0.34, much higher than -1.03 found for BLSy1 galaxies. Their black hole masses (M_BH_) have an average of log(M_BH_) of 6.9M_{sun}_, which is less than BLSy1 galaxies, which have an average of log(M_BH_) of 8.0M_{sun}_. The M_BH_ of NLSy1 galaxies is found to be correlated with their host galaxy velocity dispersion. Our analysis suggests that geometrical effects playing an important role in defining NLSy1 galaxies and their M_BH_ deficit is perhaps due to their lower inclination compared to BLSy1 galaxies.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/166/128
- Title:
- Narrow line Seyfert 1 galaxies from SDSS-DR3
- Short Name:
- J/ApJS/166/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out a systematic search for narrow line Seyfert 1 galaxies (NLS1s) from objects assigned as "QSOs" or "galaxies" in the spectroscopic sample of the Sloan Digital Sky Survey Data Release 3 (SDSS DR3) by a careful modeling of their emission lines and continua. The result is a uniform sample comprising ~2000 NLS1s. This sample dramatically increases the number of known NLS1s by a factor of ~10 over previous compilations. This paper presents the parameters of the prominent emission lines and continua, which were measured accurately with typical uncertainties <10%. Taking advantage of such an unprecedented large and uniform sample with accurately measured spectral parameters, we carried out various statistical analyses, some of which were only possible for the first time.
- ID:
- ivo://CDS.VizieR/J/AJ/124/3042
- Title:
- Narrow-line Seyfert 1 galaxies from SDSS EDR
- Short Name:
- J/AJ/124/3042
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 150 narrow-line Seyfert 1 galaxies (NLS1's) found within the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR) (Stoughton et al., 2002AJ....123..485S), only two of which were previously identified as such. This substantially increases the known number of NLS1's and provides a basic method by which to identify many more with subsequent releases of SDSS data. With its large size and homogeneous, well-defined selection criteria, this sample will help alleviate two major problems that have plagued NLS1 research in the past; namely, their relative rarity and significant differences in selection algorithms between the known samples. Forty-five of these SDSS-selected NLS1's are detected at energies of 0.1-2keV in the ROSAT All-Sky Survey (RASS) and are found to have ultrasoft X-ray spectra with photon indices of {Gamma}>~2, in agreement with previous results for NLS1's. However, about 10-20 of those NLS1's that were not detected by ROSAT have optical properties very similar to the detected objects and so should also have been detected by the RASS. This may be due to either significant intrinsic absorption in many NLS1's, or a significant subclass of NLS1's that have uncharacteristic, intrinsically flatter (hence harder) X-ray spectral energy distributions.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1948
- Title:
- Narrow line Seyfert 1 galaxies in the FBQS
- Short Name:
- J/AJ/131/1948
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the analysis of the optical spectra of 47 radio-selected narrow-line Seyfert 1 (NLS1) galaxies. These objects are a subset of the First Bright Quasar Survey (Cat. <J/AJ/112/407>) and were initially detected at 20cm (flux density limit 1Jy) in the VLA FIRST Survey.
- ID:
- ivo://CDS.VizieR/J/MNRAS/509/2377
- Title:
- Narrow-Line Seyfert 1 IR Survey
- Short Name:
- J/MNRAS/509/2377
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present a near-infrared spectroscopic survey of narrow-line Seyfert 1 galaxies in the southern hemisphere (using the SOFI instrument on the ESO-NTT telescope), sampled from optical surveys. We examine the kinematics of the broad-line region, probed by the emission line width of hydrogen (Paschen{alpha} and H{beta}). We observed 57 objects, of which we could firmly measure Paschen{alpha} in 49 cases. We find that a single Lorentzian fit (preferred on theoretical grounds) is preferred over multi-component Gaussian fits to the line profiles; a lack of narrow-line region emission, overwhelmed by the pole-on view of the broad line region (BLR) light, supports this. We recompute the catalog black hole (BH) mass estimates, using the values of FWHM and luminosity of H{beta}, both from catalog values and re-fitted Lorentzian values. We find a relationship slope greater than unity compared to the catalog values. We ascribe this to contamination by galactic light or difficulties with line flux measurements. However, the comparison of masses computed by the fitted Lorentzian and Gaussian measurements show a slope close to unity. Comparing the BH masses estimated from both Paschen{alpha} and H{beta}, the line widths and fluxes shows deviations from expected; in general, however, the computed BH masses are comparable. We posit a scenario where an intermixture of dusty and dust-free clouds (or alternately a structured atmosphere) differentially absorbs the line radiation of the BLR, due to dust absorption and hydrogen bound-free absorption.
- ID:
- ivo://CDS.VizieR/J/ApJS/155/257
- Title:
- NBC Quasar Candidate Catalog
- Short Name:
- J/ApJS/155/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 100563 unresolved, UV-excess (UVX) quasar candidates to g=21 from 2099 deg^2^ of the Sloan Digital Sky Survey (SDSS) Data Release One (DR1) imaging data. Existing spectra of 22737 sources reveals that 22191 (97.6%) are quasars; accounting for the magnitude dependence of this efficiency, we estimate that 95502 (95.0%) of the objects in the catalog are quasars. Such a high efficiency is unprecedented in broadband surveys of quasars. This "proof-of-concept" sample is designed to be maximally efficient, but still has 94.7% completeness to unresolved, g~<19.5, UVX quasars from the DR1 quasar catalog. This efficient and complete selection is the result of our application of a probability density type analysis to training sets that describe the four-dimensional color distribution of stars and spectroscopically confirmed quasars in the SDSS. Specifically, we use a nonparametric Bayesian classification, based on kernel density estimation, to parameterize the color distribution of astronomical sources - allowing for fast and robust classification. We further supplement the catalog by providing photometric redshifts and matches to FIRST/VLA, ROSAT, and USNO-B sources.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/4492
- Title:
- Nearby early-type galaxies catalog
- Short Name:
- J/MNRAS/460/4492
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of 1715 early-type galaxies from the literature, spanning the luminosity range from faint dwarf spheroidal galaxies to giant elliptical galaxies. The aim of this catalogue is to be one of the most comprehensive and publicly available collections of data on early-type galaxies. The emphasis in this catalogue lies on dwarf elliptical galaxies, for which some samples with detailed data have been published recently. For almost all of the early-type galaxies included in it, this catalogue contains data on their locations, distances, redshifts, half-light radii, the masses of their stellar populations and apparent magnitudes in various passbands. Data on metallicity and various colours are available for a majority of the galaxies presented here. The data on magnitudes, colours, metallicities and masses of the stellar populations is supplemented with entries that are based on fits to data from simple stellar population models and existing data from observations. Also, some simple transformations have been applied to the data on magnitudes, colours and metallicities in this catalog, in order to increase the homogeneity of this data. Estimates on the Sersic profiles, internal velocity dispersions, maximum rotational velocities, dynamical masses and ages are listed for several hundreds of the galaxies in this catalogue. Finally, each quantity listed in this catalogue is accompanied with information on its source, so that users of this catalogue can easily exclude data that they do not consider as reliable enough for their purposes.
- ID:
- ivo://CDS.VizieR/J/other/RAA/11.309
- Title:
- Nearby early-type galaxies in Stripe 82
- Short Name:
- J/other/RAA/11.3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We make use of the images from the Sloan Digital Sky Survey Stripe 82 (Stripe 82) to present an analysis of r band surface brightness profiles and radial color gradients (g-r, u-r) in our sample of 111 nearby early-type galaxies (ETGs). Thanks to the Stripe 82 images, each of which is co-added from about 50 single frames, we are able to pay special attention to the low-surface-brightness areas (LSB areas) of the galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/433/497
- Title:
- Nearby early-type galaxies with ionized gas. I.
- Short Name:
- J/A+A/433/497
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the aim of building a data-set of spectral properties of well studied early-type galaxies showing emission lines, we present intermediate resolution spectra of 50 galaxies in the nearby Universe. The sample, which covers several of the E and S0 morphological sub-classes, is biased toward objects that might be expected to have ongoing and recent star formation, at least in small amounts, because of the presence of the emission lines. The emission is expected to come from the combination of active galactic nuclei and star formation regions within the galaxies. Sample galaxies are located in environments corresponding to a broad range of local galaxy densities, although predominantly in low density environments. Our long-slit spectra cover the 3700-7250{AA} wavelength range with a spectral resolution of approximately 7.6{AA} at 5550{AA}. The specific aim of this paper, and our first step in the investigation, is to map the underlying galaxy stellar population by measuring, along the slit positioned along the galaxy major axis, line-strength indices at several, homogeneous galacto-centric distances. For each object we extracted 7 luminosity-weighted apertures (with radii 1.5", 2.5", 10", r_e/10_, r_e/8_, r_e/4_ and r_e/2_) corrected for the galaxy ellipticity and 4 gradients (0<r<r_e/16_, r_e/16_<r<r_e/8_, r_e/8_<r<r_e/4_ and r_e/4_<r<r_e/2_). For each aperture and gradient we measured 25 line-strength indices: 21 of the set defined by the Lick-IDS ``standard'' system (Trager et al., 1998, Cat. J/ApJS/116/1) and 4 introduced by Worthey & Ottaviani (1997, Cat. J/ApJS/111/377). Line-strength indices have been transformed to the Lick-IDS system. Indices derived then include H{beta}, Mg_1_, Mg_2_, Mgb, MgFe, Fe5270, Fe5335 commonly used in classic index-index diagrams. The paper introduces the sample, presents the observations, describes the data reduction procedures, the extraction of apertures and gradients, the determination and correction of the line-strength indices, the procedure adopted to transform them into the Lick-IDS System and the procedures adopted for the emission correction. We finally discuss the comparisons between our dataset and line-strength indices available in the literature. A significant fraction, about 60%, of galaxies in the present sample has one previous measurement in the Lick-IDS system but basically restricted within the r_e/8_ region. Line-strength measures obtained both from apertures and gradients outside this area and within the r_e/8_ region, with the present radial mapping, are completely new.
- ID:
- ivo://CDS.VizieR/J/A+A/445/79
- Title:
- Nearby early-type gal. with ionized gas. II.
- Short Name:
- J/A+A/445/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rampazzo et al., 2005, Cat. <J/A+A/433/497> (Paper I) presented a data-set of line-strength indices for 50 early-type galaxies in the nearby Universe. The galaxy sample is biased toward galaxies showing emission lines, located in environments corresponding to a broad range of local galaxy densities, although predominantly in low density environments. The present addendum enlarges the above data-set of line-strength indices by analyzing 18 additional early-type galaxies (three galaxies, NGC 3607, NGC 5077 and NGC 5898 were presented in the previous set). We measured 25 line-strength indices, defined by the Lick IDS "standard" system (Trager et al., 1998, Cat. <J/ApJS/116/1>; Worthey & Ottaviani, 1997, Cat. <J/ApJS/111/377>), for 7 luminosity weighted apertures and 4 gradients of each galaxy. This addendum presents the line-strength data-set and compares it with the available data in the literature.