- ID:
- ivo://CDS.VizieR/J/A+A/561/A140
- Title:
- Low-luminosity type-1 QSO sample
- Short Name:
- J/A+A/561/A140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recognizing the properties of the host galaxies of quasi-stellar objects (QSOs) is essential to understand the suspected coevolution of central supermassive black holes (BHs) and their host galaxies. We selected a subsample of the Hamburg/ESO survey for bright UV-excess QSOs, containing only the 99 nearest QSOs with redshift z<=0.06, that are close enough to allow detailed structural analysis. From this "low-luminosity type-1 QSO sample", we observed 20 galaxies and performed aperture photometry and bulge-disk-bar-AGN-decomposition with BUDDA on near-infrared J, H, K band images. From the photometric decomposition of these 20 objects and visual inspection of images of another 26, we find that ~50% of the hosts are disk galaxies and most of them (86%) are barred. Stellar masses, calculated from parametric models based on inactive galaxy colors, range from 2x10^9^M_{sun}_ to 2x10^11^M_{sun}_. Black hole masses measured from single epoch spectroscopy range from 1x10^6^M_{sun}_ to 5x10^8^M_{sun}_. In comparison to higher luminosity QSO samples, LLQSOs tend to have lower stellar and BH masses. Also, in the effective radius vs. mean surface-brightness projection of the fundamental plane, they lie in the transition area between luminous QSOs and "normal" galaxies. This can be seen as further evidence that they can be pictured as a "bridge" between the local Seyfert population and luminous QSOs at higher redshift. Eleven low-luminosity QSOs for which we have reliable morphological decompositions and BH mass estimations lie below the published BH mass vs. bulge luminosity relations for inactive galaxies. This could be partially explained by bulges of active galaxies containing much younger stellar populations than bulges of inactive galaxies. Also, one could suspect that their BHs are undermassive. This might hint at the growth of the host spheroid to precede that of the BH.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/587/A138
- Title:
- Low-luminosity type-1 QSO sample. V.
- Short Name:
- J/A+A/587/A138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared (NIR) H+K-band long-slit spectra of eleven galaxies that were obtained with SOFI at the NTT (ESO). The galaxies are chosen from the low-luminosity type-1 quasi-stellar object (LLQSO) sample, which comprises the 99 closest (z<=0.06) QSOs from the Hamburg/ESO survey for bright UV-excess QSOs. These objects are ideal targets to study the gap between local Seyfert galaxies and high-redshift quasars because they show much stronger AGN activity than local objects, but are still close enough for a detailed structural analysis. We fit hydrogen recombination, molecular hydrogen, and [FeII] lines after carefully subtracting the continuum emission. From the broad Pa{alpha} components, we estimated black hole masses and enlarged the sample of LLQSOs that deviate from the MBH-Lbulge relations of inactive galaxies from 12 to 16 objects. All objects show emission from hot dust (T~1200K) as well as stellar contribution. However, the respective fractions vary strongly among the objects. More than half of the objects show H_2_ emission lines, which indicate a large reservoir of molecular gas that is needed to feed the AGN and star formation. In the NIR diagnostic diagram all objects lie in the location of AGN-dominated objects. However, most of the objects show indications of star formation activity, suggesting that their offset location with respect to MBH-Lbulge relations of inactive galaxies may be a consequence of overluminous bulges.
- ID:
- ivo://CDS.VizieR/J/ApJ/653/240
- Title:
- Low-mass SDSS dwarf galaxy properties
- Short Name:
- J/ApJ/653/240
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the gas content and baryonic Tully-Fisher relationship for extremely low luminosity dwarf galaxies in the absolute magnitude range -13.5>M_r_-5logh_70_>-16. The sample is selected from the Sloan Digital Sky Survey and consists of 101 galaxies for which we have obtained follow-up HI observations using the Arecibo Observatory and Green Bank Telescope. This represents the largest homogeneous sample of dwarf galaxies at low luminosities with well-measured HI and optical properties. The sample spans a range of environments, from dense groups to truly isolated galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/462/535
- Title:
- Low-metallicity HII regions and galaxies
- Short Name:
- J/A+A/462/535
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our aims are to estimate the validity of empirical methods, such as R23, R23-P, log([NII]/H{alpha}) (N2), log[([OIII]/H{beta})/([NII]/H{alpha}] (O3N2), and log([SII]/H{alpha}) (S2), and to re-derive (or add) the calibrations of R23, N2, O3N2, and S2 indices for oxygen abundances on the basis of a large sample of galaxies with Te-based abundances. We determined the gas-phase oxygen abundance for a sample of 695 galaxies and HII regions with reliable detections of [OIII]4363, using the reliable and direct temperature-sensitive (Te) method of measuring metallicity. We selected 531 star-forming galaxies from the SDSS-DR4 database with strong emission lines, including [OIII]4363 detected at a signal-to-noise ratio higher than 5{sigma}, as well as 164 galaxies and HII regions from the literature with Te measurements. The O/H abundances were derived from a two-zone model for the temperature structure, assuming a relationship between high ionization and low ionization species.
- ID:
- ivo://CDS.VizieR/J/MNRAS/451/2723
- Title:
- Low-redshift clusters in the SAMI Pilot Survey
- Short Name:
- J/MNRAS/451/2723
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using new integral field observations of 106 galaxies in three nearby clusters, we investigate how the intrinsic scatter of the Fundamental Plane depends on the way in which the velocity dispersion and effective radius are measured. Our spatially resolved spectroscopy, combined with a cluster sample with negligible relative distance errors, allows us to derive a Fundamental Plane with minimal systematic uncertainties. From the apertures we tested, we find that velocity dispersions measured within a circular aperture with radius equal to one effective radius minimizes the intrinsic scatter of the Fundamental Plane. Using simple yet powerful Jeans dynamical models, we determine dynamical masses for our galaxies. Replacing luminosity in the Fundamental Plane with dynamical mass, we demonstrate that the resulting Mass Plane has further reduced scatter, consistent with zero intrinsic scatter. Using these dynamical models, we also find evidence for a possibly non-linear relationship between dynamical mass-to-light ratio and velocity dispersion.
- ID:
- ivo://CDS.VizieR/J/ApJ/711/928
- Title:
- Low-redshift Ly{alpha} galaxies from GALEX
- Short Name:
- J/ApJ/711/928
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We construct a sample of low-redshift Ly{alpha} emission-line selected sources from Galaxy Evolution Explorer (GALEX) grism spectroscopy of nine deep fields to study the role of Ly{alpha} emission in galaxy populations with cosmic time. Our final sample consists of 119 (141) sources selected in the redshift interval z=0.195-0.44 (z=0.65-1.25) from the FUV (NUV) channel. We classify the Ly{alpha} sources as active galactic nuclei (AGNs) if high-ionization emission lines are present in their UV spectra and as possible star-forming galaxies otherwise. We classify additional sources as AGNs using line widths for our Ly{alpha} emitter (LAE) analysis. These classifications are broadly supported by comparisons with X-ray and optical spectroscopic observations, though the optical spectroscopy identifies a small number of additional AGNs. Defining the GALEX LAE sample in the same way as high-redshift LAE samples, we show that LAEs constitute only about 5% of NUV-continuum selected galaxies at z~0.3. We also show that they are less common at z~0.3 than they are at z~3. Finally, we confirm that the z~2 Lyman break galaxies have relatively low metallicities for their luminosities, and we find that they lie in the same metallicity range as the z~0.3 Ly{alpha} galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/713/970
- Title:
- Low-resolution SED templates for AGNs and galaxies
- Short Name:
- J/ApJ/713/970
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a set of low-resolution empirical spectral energy distribution (SED) templates for active galactic nuclei (AGNs) and galaxies in the wavelength range from 0.03um to 30um based on the multi-wavelength photometric observations of the NOAO Deep-Wide Field Survey Bootes field and the spectroscopic observations of the AGN and Galaxy Evolution Survey. Our training sample is comprised of 14448 galaxies in the redshift range 0<~z<~1 and 5347 likely AGNs in the range 0<~z<~5.58. The galaxy templates correspond to the SED templates presented in 2008 by Assef et al. (Cat. J/ApJ/676/286) extended into the UV and mid-IR by the addition of FUV and NUV GALEX and MIPS 24um data for the field. We use our templates to determine photometric redshifts for galaxies and AGNs. While they are relatively accurate for galaxies ({sigma}_z_/(1+z)=0.04, with 5% outlier rejection), their accuracies for AGNs are a strong function of the luminosity ratio between the AGN and galaxy components. Somewhat surprisingly, the relative luminosities of the AGN and its host are well determined even when the photometric redshift is significantly in error. Finally, we use our templates to predict the color-color distribution of sources in the upcoming Wide-Field Infrared Survey Explorer (WISE) mission and define a color criterion to select AGNs analogous to those developed for IRAC photometry. We estimate that in between 640000 and 1700000 AGNs will be identified by these criteria, but without additional information, WISE-selected quasars will have serious completeness problems for z>~3.4.
- ID:
- ivo://CDS.VizieR/J/AJ/106/530
- Title:
- Low surface brightness disk galaxies
- Short Name:
- J/AJ/106/530
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a sample of approximately 340 low surface brightness (LSB) disk galaxies with measured redshifts in combination with the Center for Astrophysics redshift survey to test the hypothesis that LSB galaxies have a deficit of nearby companion galaxies compared to high surface brightness (HSB) disk galaxies. We find a very strong statistical deficit of galaxies located within a projected radius of 0.5 Mpc and within a velocity of 500 km/s around LSB disk galaxies compared to HSB ones. Further, comparing LSB and HSB disk galaxies which are located in the same portion of the sky indicates that the average distance to the nearest neighbor is 1.7 times farther for LSB disk galaxies. A Komologorov-Smirnoff test rules out, at greater than the 99% confidence level, the hypothesis that the distribution of nearest-neighbor distances is the same for HSB and LSB disk galaxies. We speculate that LSB disk galaxies have relatively long formation time scales and therefore must form in relative isolation. In addition, the lack of tidal interactions over a Hubble time serves to suppress the overall star-formation rate as no external trigger is available to help clump the gas. The observed low surface densities of HI in combination with the low probability of tidal interactions effectively prevents these disk galaxies from evolving very rapidly.
- ID:
- ivo://CDS.VizieR/J/ApJ/857/104
- Title:
- Low surface brightness galaxies from HSC-SSP
- Short Name:
- J/ApJ/857/104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of extended low surface brightness galaxies (LSBGs) identified in the Wide layer of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). Using the first ~200deg^2^ of the survey, we have uncovered 781 LSBGs, spanning red (g-i>=0.64) and blue (g-i<0.64) colors and a wide range of morphologies. Since we focus on extended galaxies (r_eff_=2.5"-14"), our sample is likely dominated by low-redshift objects. We define LSBGs to have mean surface brightnesses \bar{mu}_eff_(g)>24.3mag/arcsec^2^, which allows nucleated galaxies into our sample. As a result, the central surface brightness distribution spans a wide range of {mu}_0_(g)=18-27.4mag/arcsec^2^, with 50% and 95% of galaxies fainter than 24.3 and 22mag/arcsec^2^, respectively. Furthermore, the surface brightness distribution is a strong function of color, with the red distribution being much broader and generally fainter than that of the blue LSBGs, and this trend shows a clear correlation with galaxy morphology. Red LSBGs typically have smooth light profiles that are well characterized by single-component Sersic functions. In contrast, blue LSBGs tend to have irregular morphologies and show evidence for ongoing star formation. We cross-match our sample with existing optical, HI, and ultraviolet catalogs to gain insight into the physical nature of the LSBGs. We find that our sample is diverse, ranging from dwarf spheroidals and ultradiffuse galaxies in nearby groups to gas-rich irregulars to giant LSB spirals, demonstrating the potential of the HSC-SSP to provide a truly unprecedented view of the LSBG population.
- ID:
- ivo://CDS.VizieR/J/A+A/296/643
- Title:
- Low Surface Brightness galaxies in Coma
- Short Name:
- J/A+A/296/643
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the prime focus of the 6-meter telescope, we have searched for low surface brightness dwarf galaxies in two regions in the Coma cluster: one in the center of the cluster and the other one 40arcmin to the west. The observations were carried out with a total exposure time 4x5x600sec and with a 1.2arcsec seeing. Our survey is complete down to V=25.5 and R=25.0mag. The central field shows an excess of faint galaxies (121 versus 104 in the reference field) significant at a one sigma level only. However, the central-field excess is mainly caused by the presence of faint (V=24/25mag), neutral colour (V-R=0.3/0.4) objects of low surface brightness, SB=26.0/26.5mag/arcsec^2^. These characteristics are quite consistent with those of the dwSph's in the Local Group which have typically M_v_~10mag and A~1kpc. The observed excess corresponds to a surface number density of 4gal/arcmin^2^ in the center of Coma, thus implying a total population of cluster dwarfs of ~4000 down to the limiting absolute magnitude -10mag. The number ratio of LSBD's to normal galaxies (with M<-18mag for normals) in Coma turns out to be 20:1. Such ratio is comparable to that observed in other rich clusters: A3574 (14:1) and A1367 (6:1), but is much larger than the 2:1 ratio obtained for moderate nearby clusters such as Virgo, Fornax, Antlia.
