- ID:
- ivo://CDS.VizieR/J/MNRAS/476/4488
- Title:
- LSBG HI and optical properties
- Short Name:
- J/MNRAS/476/4488
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the HI and optical properties of nearby (z<=0.1) Low Surface Brightness galaxies (LSBGs). We started with a literature sample of ~900 LSBGs and divided them into three morphological classes: spirals, irregulars, and dwarfs. Of these, we could use ~490 LSBGs to study their HI and stellar masses, colours, and colour-magnitude diagrams, and local environment, compare them with normal, High Surface Brightness (HSB) galaxies and determine the differences between the three morphological classes. We found that LSB and HSB galaxies span a similar range in HI and stellar masses, and have a similar M_HI_/M_{star}_-M_{star}_ relationship. Among the LSBGs, as expected, the spirals have the highest average HI and stellar masses, both of about 10^9.8^M_{sun}_. The LSGBs' (g-r) integrated colour is nearly constant as function of HI mass for all classes. In the colour-magnitude diagram, the spirals are spread over the red and blue regions whereas the irregulars and dwarfs are confined to the blue region. The spirals also exhibit a steeper slope in the M_HI_/M_{star}_-M_{star}_ plane. Within their local environment, we confirmed that LSBGs are more isolated than HSB galaxies, and LSB spirals more isolated than irregulars and dwarfs. Kolmogorov-Smirnov statistical tests on the HI mass, stellar mass, and number of neighbours indicate that the spirals are a statistically different population from the dwarfs and irregulars. This suggests that the spirals may have different formation and HI evolution than the dwarfs and irregulars.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/458/341
- Title:
- LSBG in Arecibo HI Strip Survey
- Short Name:
- J/A+A/458/341
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to estimate the contribution of low surface brightness (LSB) galaxies to the local (z<=0.1) galaxy number density, we performed an optical search for LSB candidates in a 15.5{deg}^2^ part of the region covered by the 65{deg}^2^ blind Arecibo HI Strip Survey (AHISS)
- ID:
- ivo://CDS.VizieR/J/ApJ/804/34
- Title:
- Luminous AGNs and early-type SDSS galaxies
- Short Name:
- J/ApJ/804/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is not yet clear what triggers the activity of active galactic nuclei (AGNs), but galaxy merging has been suspected to be one of the main mechanisms fueling the activity. Using deep optical images taken at various ground-based telescopes, we investigate the fraction of galaxy mergers in 39 luminous AGNs (M_R_<~-22.6mag) at z<=0.3 (a median redshift of 0.155), for which the host galaxies are generally considered as early-type galaxies. Through visual inspection of the images, we find that 17 of 39 AGN host galaxies (43.6%) show evidence for current or past mergers like tidal tails, shells, and disturbed morphology. In order to see if this fraction is abnormally high, we also examined the merging fraction of normal early-type galaxies in the Sloan Digital Sky Survey (SDSS) Stripe 82 data (a median redshift of 0.04), of which the surface-brightness limit is comparable to our imaging data. To correct for the effects related to the redshift difference of the two samples, we performed an image simulation by putting a bright point source as an artificial AGN in the images of SDSS early-type galaxies and placing them onto the redshifts of AGNs. The merging fraction in this realistic sample of simulated AGNs is only ~5-15% (1/4 to 1/8 of that of real AGNs). Our result strongly suggests that luminous AGN activity is associated with galaxy merging.
- ID:
- ivo://CDS.VizieR/J/MNRAS/479/3509
- Title:
- LVHIS. far-infrared radio correlation
- Short Name:
- J/MNRAS/479/3509
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we measure the far-infrared (FIR) and radio flux densities of a sample of 82 local gas-rich galaxies, including 70 "dwarf" galaxies (M_*_<10^9^M_{sun}_), from the Local Volume HI Survey (LVHIS), which is close to volume limited. It is found that LVHIS galaxies hold a tight linear FIR-radio correlation (FRC) over four orders of magnitude. However, for detected galaxies only, a trend of larger FIR-to-radio ratio with decreasing flux density is observed. We estimate the star formation rate by combining UV and mid-IR data using empirical calibration. It is confirmed that both FIR and radio emission are strongly connected with star formation but with significant non-linearity. Dwarf galaxies are found radiation deficient in both bands, when normalized by star formation rate. It urges a "conspiracy" to keep the FIR-to-radio ratio generally constant. By using partial correlation coefficient in Pearson definition, we identify the key galaxy properties associated with the FIR and radio deficiency. Some major factors, such as stellar mass surface density, will cancel out when taking the ratio between FIR and radio fluxes. The remaining factors, such as HI-to-stellar mass ratio and galaxy size, are expected to cancel each other due to the distribution of galaxies in the parameter space. Such cancellation is probably responsible for the "conspiracy" to keep the FRC alive.
- ID:
- ivo://CDS.VizieR/J/ApJ/771/40
- Title:
- Main-sequence A, F, G, and K stars photometry
- Short Name:
- J/ApJ/771/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on CHARA Array measurements, we present the angular diameters of 23 nearby, main-sequence stars, ranging from spectral types A7 to K0, 5 of which are exoplanet host stars. We derive linear radii, effective temperatures, and absolute luminosities of the stars using Hipparcos parallaxes and measured bolometric fluxes. The new data are combined with previously published values to create an Angular Diameter Anthology of measured angular diameters to main-sequence stars (luminosity classes V and IV). This compilation consists of 125 stars with diameter uncertainties of less than 5%, ranging in spectral types from A to M. The large quantity of empirical data is used to derive color-temperature relations to an assortment of color indices in the Johnson (BVR_J_I_J_JHK), Cousins (R_C_I_C_), Kron (R_K_I_K_), Sloan (griz), and WISE (W_3_W_4_) photometric systems. These relations have an average standard deviation of ~3% and are valid for stars with spectral types A0-M4. To derive even more accurate relations for Sun-like stars, we also determined these temperature relations omitting early-type stars (T_eff_>6750K) that may have biased luminosity estimates because of rapid rotation; for this subset the dispersion is only ~2.5%. We find effective temperatures in agreement within a couple of percent for the interferometrically characterized sample of main-sequence stars compared to those derived via the infrared flux method and spectroscopic analysis.
- ID:
- ivo://CDS.VizieR/J/MNRAS/476/1765
- Title:
- MaNGA E and S galaxies properties
- Short Name:
- J/MNRAS/476/1765
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform full spectrum fitting stellar population analysis and Jeans Anisotropic modelling of the stellar kinematics for about 2000 early-type galaxies (ETGs) and spiral galaxies from the MaNGA DR14 sample. Galaxies with different morphologies are found to be located on a remarkably tight mass plane which is close to the prediction of the virial theorem, extending previous results for ETGs. By examining an inclined projection ('the mass-size' plane), we find that spiral and early-type galaxies occupy different regions on the plane, and their stellar population properties (i.e. age, metallicity, and stellar mass-to-light ratio) vary systematically along roughly the direction of velocity dispersion, which is a proxy for the bulge fraction. Galaxies with higher velocity dispersions have typically older ages, larger stellar mass-to-light ratios and are more metal rich, which indicates that galaxies increase their bulge fractions as their stellar populations age and become enriched chemically. The age and stellar mass-to-light ratio gradients for low-mass galaxies in our sample tend to be positive (centre<outer), while the gradients for most massive galaxies are negative. The metallicity gradients show a clear peak around velocity dispersion log_10_{sigma}_e_~=2.0, which corresponds to the critical mass ~3x10^10^M_{sun}_ of the break in the mass-size relation. Spiral galaxies with large mass and size have the steepest gradients, while the most massive ETGs, especially above the critical mass M_crit_>=2x 10^11^M_{sun}_, where slow rotator ETGs start dominating, have much flatter gradients. This may be due to differences in their evolution histories, e.g. mergers.
- ID:
- ivo://CDS.VizieR/J/AJ/116/1094
- Title:
- MAPS-PP catalog of galaxies
- Short Name:
- J/AJ/116/1094
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A search for preferential galaxy alignments in the Pisces-Perseus Supercluster (PPS) is made using the Minnesota Automated Plate Scanner Pisces-Perseus Survey (MAPS-PP). The MAPS-PP is a catalog of ~1400 galaxies with a (roughly) isophotal diameter greater than 30" constructed from digitized scans of the blue and red plates of the Palomar Observatory Sky Survey covering the PPS. This is the largest sample of galaxies applied to a search of galaxy alignments in this supercluster, and it has been used in combination with previously published redshifts to construct the deepest PPS galaxy luminosity function to date. While previous studies have relied extensively on catalogs with visually estimated parameters for both sample selection and determination of galaxy orientation, the MAPS-PP uses selection criteria and measurements that are entirely machine and computer based. Therefore, it is not susceptible to some of the biases, such as the diameter inclination effect, known to exist in some other galaxy catalogs. The presence of anisotropic galaxy distributions is determined by use of the Kuiper statistic, a robust alternative to the chi^2 statistic more traditionally used in these studies.
- ID:
- ivo://CDS.VizieR/J/AJ/149/171
- Title:
- 2MASS galaxy group catalog
- Short Name:
- J/AJ/149/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A galaxy group catalog is built from the sample of the 2MASS Redshift Survey almost complete to K_s_=11.75 over 91% of the sky. Constraints in the construction of the groups were provided by scaling relations determined by close examination of well defined groups with masses between 10^11^ and 10^15^M_{sun}_. Group masses inferred from K_s_ luminosities are statistically in agreement with masses calculated from application of the virial theorem. While groups have been identified over the full redshift range of the sample, the properties of the nearest and farthest groups are uncertain and subsequent analysis has only considered groups with velocities between 3000 and 10000km/s. The 24044 galaxies in this range are identified with 13607 entities, 3461 of them with two or more members. A group mass function is constructed. The Sheth-Tormen formalism provides a good fit to the shape of the mass function for group masses above 6h^-1^x10^12^M_{sun}_ but the count normalization is poor. Summing all the mass associated with the galaxy groups between 3000 and 10000km/s gives a density of collapsed matter as a fraction of the critical density of {Omega}_collapsed_=0.16.
- ID:
- ivo://CDS.VizieR/J/ApJ/668/906
- Title:
- Massive clumps in NGC 6334
- Short Name:
- J/ApJ/668/906
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of dust continuum emission at 1.2mm toward the star-forming region NGC 6334 made with the SEST SIMBA bolometer array. The observations cover an area of ~2deg^2^ with approximately uniform noise. We detected 181 clumps spanning almost 3 orders of magnitude in mass (3-6x10^3^M_{sun}_) and with sizes in the range 0.1-1.0pc.
- ID:
- ivo://CDS.VizieR/J/A+A/600/L10
- Title:
- Massive cluster progenitors from ATLASGAL
- Short Name:
- J/A+A/600/L10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The early evolution of massive cluster progenitors is poorly understood. We investigate the fragmentation properties from 0.3pc to 0.06pc scales of a homogenous sample of infrared-quiet massive clumps within 4.5kpc selected from the ATLASGAL survey. Using the ALMA 7m array we detect compact dust continuum emission towards all targets and find that fragmentation, at these scales, is limited. The mass distribution of the fragments uncovers a large fraction of cores above 40M_{sun}_, corresponding to massive dense cores (MDCs) with masses up to ~400M_{sun}_. Seventy-seven percent of the clumps contain at most 3 MDCs per clump, and we also reveal single clumps/MDCs. The most massive cores are formed within the more massive clumps and a high concentration of mass on small scales reveals a high core formation efficiency. The mass of MDCs highly exceeds the local thermal Jeans mass, and we lack the observational evidence of a survey efficiently high level of turbulence or strong enough magnetic fields to keep the most massive MDCs in equilibrium. If already collapsing, the observed fragmentation properties with a high core formation efficiency are consistent with the collapse setting in at parsec scales.
