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2201. Mass models of 171 galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/477/4187
Title:
Mass models of 171 galaxies
Short Name:
J/MNRAS/477/4187
Date:
21 Oct 2021
Publisher:
CDS
Description:
Mass models of a sample of 171 low- and high-surface brightness galaxies are presented in the context of the cold dark matter (CDM) theory using the NFW dark matter halo density distribution to extract a new concentration-viral mass relation (c-M_vir_). The rotation curves (RCs) are calculated from the total baryonic matter based on the 3.6{mu}m-band surface photometry, the observed distribution of neutral hydrogen, and the dark halo, in which the three adjustable parameters are the stellar mass-to-light ratio, halo concentration, and virial mass. Although accounting for a NFW dark halo profile can explain RC observations, the implied c-M_vir_ relation from RC analysis strongly disagrees with that resulting from different cosmological simulations. Also, the M/L-colour correlation of the studied galaxies is inconsistent with that expected from stellar population synthesis models with different stellar initial mass functions. Moreover, we show that the best-fitting stellar M/L ratios of 51 galaxies (30 per cent of our sample) have unphysically negative values in the framework of the {Lambda}CDM theory. This can be interpreted as a serious crisis for this theory. This suggests either that the commonly used NFW halo profile, which is a natural result of {Lambda}CDM cosmological structure formation, is not an appropriate profile for the dark haloes of galaxies, or, new dark matter physics or alternative gravity models are needed to explain the rotational velocities of disc galaxies.
2202. 2MASS observations of IRAS 1Jy ULIRGs
ID:
ivo://CDS.VizieR/J/AJ/131/1942
Title:
2MASS observations of IRAS 1Jy ULIRGs
Short Name:
J/AJ/131/1942
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Two Micron All Sky Survey observation of the IRAS 1Jy sample of ultraluminous infrared galaxies (ULIRGs) is presented in this paper. Together with the IRAS photometric data, the properties and energy sources of the IRAS 1Jy sample of ULIRGs in the near- and far-infrared are discussed.
2203. 2MASS-selected Flat Galaxy Catalog (2MFGC)
ID:
ivo://CDS.VizieR/J/other/BSAO/57.5
Title:
2MASS-selected Flat Galaxy Catalog (2MFGC)
Short Name:
J/other/BSAO/57.
Date:
21 Oct 2021
Publisher:
CDS
Description:
An all-sky catalog of 18020 disc-like galaxies is presented. The galaxies are selected from the Extended Source Catalog of the Two Micron All-Sky Survey (XSC 2MASS) basing on their 2MASS axial ratio a/b>=3. The Catalog contains data on magnitudes of a galaxy in the J, H, Ks bands, its axial ratio, positional angle, index of luminosity concentration, as well as identification of the galaxy with the LEDA and the NED databases. Unlike the available optical catalogs, the new 2MFGC catalog seems to be more suitable to study cosmic streaming on a scale of z~0.1. The dipole moment of distribution of the bright (K<11mag) 2MFGC objects (l=227{deg}, b=41{deg} or SGL=90{deg}, SGB=-43{deg}) lies within statistical errors (+/-15{deg}) in the direction of the IRAS dipole and the optical RFGC dipole.
2204. 2MASS-selected Isolated Galaxies (2MIG)
ID:
ivo://CDS.VizieR/VII/257
Title:
2MASS-selected Isolated Galaxies (2MIG)
Short Name:
VII/257
Date:
21 Oct 2021
Publisher:
CDS
Description:
We undertook searches for isolated galaxies based on automatic selection of infrared sources from the Two Micron All-Sky Survey (2MASS, Cat. II/246) followed by a visual inspection of their surrounding. Using a modified criterion by Karachentseva (1973SoSAO...8....3K), we compiled a catalog of 3227 isolated galaxies (2MIG) containing 6% of 2MASS Extended Sources (2MASX, Cat. VII/233) brighter than K_s_=12mag with angular diameters a_K_<=30". The most isolated 2493 galaxies among them enter in the 2MASS Very Isolated Galaxy Catalog, 2MVIG. Being situated in the regions of extremely low mass density, the 2MVIG galaxies can serve as a reference sample for investigation the influence of environment on structure and evolution of galaxies.
2205. Mass-to-light ratio of binary galaxies
ID:
ivo://CDS.VizieR/J/ApJ/516/693
Title:
Mass-to-light ratio of binary galaxies
Short Name:
J/ApJ/516/693
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on the mass-to-light ratio determination based on a newly selected binary galaxy sample, which includes a large number of pairs whose separations exceed a few hundred kpc. The probability distributions of the projected separation and the velocity difference have been calculated considering the contamination of optical pairs, and the mass-to-light (M/L) ratio has been determined based on the maximum likelihood method. The best estimate of the M/L in the B band for 57 pairs is found to be 28 - 36 depending on the orbital parameters and the distribution of optical pairs (solar unit: H_o_ = 50 km s^-1^ Mpc^-1^). The best estimate of the M/L for 30 pure spiral pairs is found to be 12 - 16. These results are relatively smaller than those obtained in previous studies but are consistent with each other within the errors. Although the number of pairs with large separation is significantly increased compared with previous samples, the M/L does not show any tendency of increase but is found to be almost independent of the separation of pairs beyond 100 kpc. The constancy of the M/L beyond 100 kpc may indicate that the typical halo size of spiral galaxies is less than 100 kpc.
2206. Mass-to-light ratios in low-mass early-type gal.
ID:
ivo://CDS.VizieR/J/ApJ/850/15
Title:
Mass-to-light ratios in low-mass early-type gal.
Short Name:
J/ApJ/850/15
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present dynamical measurements of the central mass-to-light ratio (M/L) of a sample of 27 low-mass early-type ATLAS^3D^ galaxies. We consider all ATLAS^3D^ galaxies with 9.7<log(M*/M_{sun}_)<10.5 in our analysis, selecting out galaxies with available high-resolution Hubble Space Telescope (HST) data, and eliminating galaxies with significant central color gradients or obvious dust features. We use the HST images to derive mass models for these galaxies and combine these with the central velocity dispersion values from ATLAS^3D^ data to obtain a central dynamical M/L estimate. These central dynamical M/Ls are higher than dynamical M/Ls derived at larger radii and stellar population estimates of the galaxy centers in ~80% of galaxies, with a median enhancement of ~14% and a statistical significance of 3.3{sigma}. We show that the enhancement in the central M/L is best described either by the presence of black holes in these galaxies or by radial initial mass function variations. Assuming a black hole model, we derive black hole masses for the sample of galaxies. In two galaxies, NGC 4458 and NGC 4660, the data suggest significantly overmassive black holes, while in most others only upper limits are obtained. We also show that the level of M/L enhancements we see in these early-type galaxy nuclei are consistent with the larger enhancements seen in ultracompact dwarf galaxies (UCDs), supporting the scenario where massive UCDs are created by stripping galaxies of these masses.
2207. 2MASS view of Sgr dSph. VII. Kinematics
ID:
ivo://CDS.VizieR/J/ApJ/756/74
Title:
2MASS view of Sgr dSph. VII. Kinematics
Short Name:
J/ApJ/756/74
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have assembled a large-area spectroscopic survey of giant stars in the Sagittarius (Sgr) dwarf galaxy core. Using medium resolution (R~15000), multifiber spectroscopy we have measured velocities of these stars, which extend up to 12{deg} from the galaxy's center (3.7 core radii or 0.4 times the King limiting radius). From these high-quality spectra we identify 1310 Sgr members out of 2296 stars surveyed, distributed across 24 different fields across the Sgr core. Additional slit spectra were obtained of stars bridging from the Sgr core to its trailing tail. Our systematic, large-area sample shows no evidence for significant rotation, a result at odds with the ~20km/s rotation required as an explanation for the bifurcation seen in the Sgr tidal stream; the observed small (<=4km/s) velocity trend primarily along the major axis is consistent with models of the projected motion of an extended body on the sky with no need for intrinsic rotation. The Sgr core is found to have a flat velocity dispersion (except for a kinematically colder center point) across its surveyed extent and into its tidal tails, a property that matches the velocity dispersion profiles measured for other Milky Way dwarf spheroidal (dSph) galaxies. We comment on the possible significance of this observed kinematical similarity for the dynamical state of the other classical Milky Way dSphs in light of the fact that Sgr is clearly a strongly tidally disrupted system.
2208. Mass, Z, dust attenuation, and SFR relations
ID:
ivo://CDS.VizieR/J/ApJ/847/18
Title:
Mass, Z, dust attenuation, and SFR relations
Short Name:
J/ApJ/847/18
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyze the optical continuum of star-forming galaxies in the Sloan Digital Sky Survey by fitting stacked spectra with stellar population synthesis models to investigate the relation between stellar mass, stellar metallicity, dust attenuation, and star formation rate. We fit models calculated with star formation and chemical evolution histories that are derived empirically from multi-epoch observations of the stellar mass-star formation rate and the stellar mass-gas-phase metallicity relations, respectively. We also fit linear combinations of single-burst models with a range of metallicities and ages. Star formation and chemical evolution histories are unconstrained for these models. The stellar mass-stellar metallicity relations obtained from the two methods agree with the relation measured from individual supergiant stars in nearby galaxies. These relations are also consistent with the relation obtained from emission-line analysis of gas-phase metallicity after accounting for systematic offsets in the gas-phase metallicity. We measure dust attenuation of the stellar continuum and show that its dependence on stellar mass and star formation rate is consistent with previously reported results derived from nebular emission lines. However, stellar continuum attenuation is smaller than nebular emission line attenuation. The continuum-to-nebular attenuation ratio depends on stellar mass and is smaller in more massive galaxies. Our consistent analysis of stellar continuum and nebular emission lines paves the way for a comprehensive investigation of stellar metallicities of star-forming and quiescent galaxies.
2209. 2MASX/NVSS galaxies brighter than K_20fe_=12.25
ID:
ivo://CDS.VizieR/J/ApJ/872/148
Title:
2MASX/NVSS galaxies brighter than K_20fe_=12.25
Short Name:
J/ApJ/872/148
Date:
21 Oct 2021
Publisher:
CDS
Description:
We identified 15658 NRAO VLA Sky Survey (NVSS) radio sources among the 55288 2 Micron All-Sky Survey eXtended (2MASX) galaxies brighter than k_20fe_=12.25 at {lambda}=2.16{mu}m and covering the {Omega}=7.016sr of sky defined by J2000 {delta}>-40{deg} and |b|>20{deg}. The complete sample of 15043 galaxies with 1.4GHz flux densities S>=2.45mJy contains a 99.9% spectroscopically complete subsample of 9517 galaxies with k_20fe_<=11.75. We used only radio and infrared data to quantitatively distinguish radio sources powered primarily by recent star formation from those powered by active galactic nuclei. The radio sources with log[L(W/Hz)]>19.3 that we used to derive the local spectral luminosity and power-density functions account for >99% of the total 1.4GHz spectral power densities U_SF_=(1.54+/-0.20)x10^19^W/Hz/Mpc^3^ and U_AGN_=(4.23+/-0.78)x10^19^W/Hz/Mpc^3^ in the universe today, and the spectroscopic subsample is large enough that the quoted errors are dominated by cosmic variance. The recent comoving star formation rate density indicated by USF is {psi}~0.015M_{sun}_/yr/Mpc^3^.
2210. Matched SDSS and FIRST Sample
ID:
ivo://CDS.VizieR/J/AJ/137/42
Title:
Matched SDSS and FIRST Sample
Short Name:
J/AJ/137/42
Date:
21 Oct 2021
Publisher:
CDS
Description:
The question as to whether the distribution of radio loudness in active galactic nuclei (AGNs) is actually bimodal has been discussed extensively in the literature. Furthermore, there have been claims that radio loudness depends on black hole mass (M_BH_) and Eddington ratio (L_bol_/L_Edd_).We investigate these claims using the low- redshift broad line AGN sample of Greene & Ho (2007ApJ...667..131G), which consists of 8434 objects at z<0.35 from the Sloan Digital Sky Survey Fourth Data Release (SDSS DR4). We obtained radio fluxes from the Very Large Array Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey for the SDSS AGN. Out of the 8434 SDSS AGNs, 821 have corresponding observed radio fluxes in the FIRST survey.

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