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21471. 3.6um surface brightness from S4G
ID:
ivo://CDS.VizieR/J/ApJ/772/135
Title:
3.6um surface brightness from S4G
Short Name:
J/ApJ/772/135
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the m=1 distortions (lopsidedness) in the stellar components of 167 nearby galaxies that span a wide range of morphologies and luminosities. We confirm the previous findings of (1) a high incidence of lopsidedness in the stellar distributions, (2) increasing lopsidedness as a function of radius out to at least 3.5 exponential scale lengths, and (3) greater lopsidedness, over these radii, for galaxies of later type and lower surface brightness. Additionally, the magnitude of the lopsidedness (1) correlates with the character of the spiral arms (stronger arm patterns occur in galaxies with less lopsidedness), (2) is not correlated with the presence or absence of a bar, or the strength of the bar when one is present, (3) is inversely correlated to the stellar mass fraction, f_*_, within one radial scale length, and (4) correlates directly with f_*_ measured within the radial range over which we measure lopsidedness. We interpret these findings to mean that lopsidedness is a generic feature of galaxies and does not, generally, depend on a rare event, such as a direct accretion of a satellite galaxy onto the disk of the parent galaxy. While lopsidedness may be caused by several phenomena, moderate lopsidedness (<A_1_>_i_+<A_1_>_o_)/2<0.3) is likely to reflect halo asymmetries to which the disk responds or a gravitationally self-generated mode. We hypothesize that the magnitude of the stellar response depends both on how centrally concentrated the stars are with respect to the dark matter and whether there are enough stars in the region of the lopsidedness that self-gravity is dynamically important.
21472. 14.3um survey in the Lockman Hole
ID:
ivo://CDS.VizieR/J/A+A/427/23
Title:
14.3um survey in the Lockman Hole
Short Name:
J/A+A/427/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the image and catalogue of the 14.3{mu}m hallow survey of 0.55 square degrees in the region of the Lockman Hole (10h 52m 03s, +57{deg} 21' 46", J2000). The data have been analyzed with the recent algorithm by Lari et al. (2001, Cat. <J/MNRAS/325/1173>) conceived to exploit ISO data in an optimal way, especially in the case of shallow surveys with low redundancy. Photometry has been accurately evaluated through extensive simulations and also the absolute calibration has been checked using a set of 21 stars detected at 14.3{mu}m, optical, and near-IR bands.
21473. 3.6um, 4.5um, B and V light curves of NGC 6418
ID:
ivo://CDS.VizieR/J/ApJ/801/127
Title:
3.6um, 4.5um, B and V light curves of NGC 6418
Short Name:
J/ApJ/801/127
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from a 15 month campaign of high-cadence (~3 days) mid-infrared Spitzer and optical (B and V) monitoring of the Seyfert 1 galaxy NGC 6418, with the objective of determining the characteristic size of the dusty torus in this active galactic nucleus (AGN). We find that the 3.6 and 4.5{mu}m flux variations lag behind those of the optical continuum by 37.2_-2.2_^+2.4^-days and 47.1_-3.1_^+3.1^-days, respectively. We report a cross-correlation time lag between the 4.5 and 3.6{mu}m flux of 13.9_-0.1_^+0.5^ days. The lags indicate that the dust emitting at 3.6 and 4.5{mu}m is located at a distance ~1-light-month (~0.03pc) from the source of the AGN UV-optical continuum. The reverberation radii are consistent with the inferred lower limit to the sublimation radius for pure graphite grains at 1800K, but smaller by a factor of ~2 than the corresponding lower limit for silicate grains; this is similar to what has been found for near-infrared (K-band) lags in other AGNs. The 3.6 and 4.5{mu}m reverberation radii fall above the K-band {tau}{propto}L^0.5^ size-luminosity relationship by factors <~2.8 and <~3.4, respectively, while the 4.5{mu}m reverberation radius is only 27% larger than the 3.6{mu}m radius. This is broadly consistent with clumpy torus models, in which individual optically thick clouds emit strongly over a broad wavelength range.
21474. UNAM-KIAS catalog of isolated galaxies
ID:
ivo://CDS.VizieR/J/AJ/139/2525
Title:
UNAM-KIAS catalog of isolated galaxies
Short Name:
J/AJ/139/2525
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new catalog of isolated galaxies from the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) is presented. A total of 1520 isolated galaxies were found in 1.4sr of sky. The selection criteria in this UNAM-KIAS catalog are a variation on the criteria developed by Karachentseva, including full redshift information. Through an image processing pipeline that takes advantage of the high-resolution (~0.4"/pix) and high dynamic range of the SDSS images, a uniform g-band morphological classification for all these galaxies is presented.
21475. Unbiased census of AGN in 2MASS
ID:
ivo://CDS.VizieR/J/AJ/127/646
Title:
Unbiased census of AGN in 2MASS
Short Name:
J/AJ/127/646
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an unbiased near-IR-selected AGN sample, covering 12.56deg^2^ down to Ks~15.5, selected from the Two Micron All Sky Survey (2MASS). Our only selection effect is a moderate color cut (J-Ks>1.2) designed to reduce contamination from Galactic stars. We observed both pointlike and extended sources.
21476. Unbiased sample of CSS and GPS
ID:
ivo://CDS.VizieR/J/MNRAS/416/1135
Title:
Unbiased sample of CSS and GPS
Short Name:
J/MNRAS/416/1135
Date:
21 Oct 2021
Publisher:
CDS
Description:
Compact Steep Spectrum (CSS) and Gigahertz Peaked Spectrum (GPS) sources are classes of compact, powerful, extragalactic objects. These sources are thought to be the earliest stages in the evolution of radio galaxies, capturing the ignition (or, in some cases, re-ignition) of the active galactic nucleus. As well as serving as probes of the early stages of large-scale radio sources, these sources are good, stable, amplitude calibrators for radio telescopes. We present an unbiased flux density limited (>1.5Jy at 2.7GHz) catalogue of these objects in the Southern hemisphere, including tabulated data, radio spectra, and where available, optical images and measurements. The catalogue contains 26 sources, consisting of two new candidates and 15 known CSS sources, and nine known GPS sources. We present new Australia Telescope Compact Array (ATCA) data on 10 of these 26 sources, and data on a further 42 sources which were excluded from our final sample. This bright sample will serve as a reference sample for comparison with subsequent faint (mJy level) samples of CSS and GPS candidates currently being compiled.
21477. Uncertainties in r-abundance distribution
ID:
ivo://CDS.VizieR/J/A+A/342/881
Title:
Uncertainties in r-abundance distribution
Short Name:
J/A+A/342/881
Date:
21 Oct 2021
Publisher:
CDS
Description:
Tables 1&2 correspond to the first estimate of the error factors affecting the {beta} decay rates of highly ionized heavy atoms in stellar environments. The uncertainties in the stellar {beta}-decay and EC rates strongly depend on the relevance of the experimentally unknown transitions at a given temperature and density and the reliability of their evaluated probability. To estimate the temperature- and density-dependent errors on the {beta}-decay rates, we have reiterated the Yokoi & Takahashi (1987, At. Data Nucl. Data Tables 36, 375) calculation with unknown transition rates modified by a typical error value of log(ft)=+/-0.5 (Takahashi 1998, private communication). No transition faster than log(ft)=5 is permitted in this error calculation. Newly measured transition probabilities, e.g. the allowed transition in the ^187^Re bound-state {beta}-decay (Bosch et al., 1996PhRvL..77.5190B), have been considered. Minimum and maximum error factors around the published rates of Yokoi & Takahashi (1987) are given in Tables 1 and 2 at temperatures 1<=T_8_<=4 and electronic densities (expressed in terms of 10^26^cm^-3^ of 1<=N_e_<=30. When the density-dependence does not affect the final uncertainty factor by more than 0.10 between the N_e_=1 and 3 cases, only values at N_e_=10 are given in the tables. Note that an increase of transition probability by log(ft)=0.5 gives rise to an increase of the final rate by a maximum value of 3.16. This maximum variation is obtained for many rates. The derived error factors are used in parametric s-process calculations within the canonical multi-event model to estimate their impact on the predicted s-abundance distribution and the resulting uncertainties on the solar r-abundance distribution.
21478. "Under-massive" black hole candidates
ID:
ivo://CDS.VizieR/J/ApJ/798/54
Title:
"Under-massive" black hole candidates
Short Name:
J/ApJ/798/54
Date:
21 Oct 2021
Publisher:
CDS
Description:
Several recent papers have reported on the occurrence of active galactic nuclei (AGNs) containing undermassive black holes relative to a linear scaling relation between black hole mass (M_bh_) and host spheroid stellar mass (M_sph,*_). However, dramatic revisions to the M_bh_-M_sph,*_ and M_bh_-L_sph_ relations, based on samples containing predominantly inactive galaxies, have recently identified a new steeper relation at M_bh_<~(2-10)x10^8^M_{sun}_, roughly corresponding to M_sph,*_<~(0.3-1)x10^11^M_{sun}_. We show that this steeper, quadratic-like M_bh_-M_sph,*_ relation defined by the Sersic galaxies, i.e., galaxies without partially depleted cores, roughly tracks the apparent offset of the AGN having 10^5^<~M_bh_/M_{sun}_<~0.5x10^8^. That is, these AGNs are not randomly offset with low black hole masses, but also follow a steeper (nonlinear) relation. As noted by Busch et al. (2014, J/A+A/561/A140), confirmation or rejection of a possible AGN offset from the steeper M_bh_-M _sph,*_ relation defined by the Sersic galaxies will benefit from improved stellar mass-to-light ratios for the spheroids hosting these AGNs. Several implications for formation theories are noted. Furthermore, reasons for possible under- and overmassive black holes, the potential existence of intermediate mass black holes (<10^5^M_{sun}_), and the new steep (black hole)-(nuclear star cluster) relation, M_bh_{propto}M_nc_^2.7+/-0.7^, are also discussed.
21479. UniDAM results
ID:
ivo://CDS.VizieR/J/A+A/604/A108
Title:
UniDAM results
Short Name:
J/A+A/604/A108
Date:
21 Oct 2021
Publisher:
CDS
Description:
Galactic archaeology, the study of the formation and evolution of the Milky Way by reconstructing its past from its current constituents, requires precise and accurate knowledge of stellar parameters for as many stars as possible. To achieve this, a number of large spectroscopic surveys have been undertaken and are still ongoing. So far consortia carrying out the different spectroscopic surveys have used different tools to determine stellar parameters of stars from their derived effective temperatures, surface gravities, and metallicities; the parameters can be combined with photometric, astrometric, interferometric, or asteroseismic information. Here we aim to homogenise the stellar characterisation by applying a unified tool to a large set of publicly available spectrophotometric data. We used spectroscopic data from a variety of large surveys combined with infrared photometry from 2MASS and AllWISE and compared these in a Bayesian manner with PARSEC isochrones to derive probability density functions (PDFs) for stellar masses, ages, and distances. We treated PDFs of pre-helium-core burning, helium-core burning, and post helium-core burning solutions as well as different peaks in multimodal PDFs (i.e. each unimodal sub-PDF) of the different evolutionary phases separately. For over 2.5 million stars we report mass, age, and distance estimates for each evolutionary phase and unimodal sub-PDF. We report Gaussian, skewed, Gaussian, truncated Gaussian, modified truncated exponential distribution or truncated Student's t-distribution functions to represent each sub-PDF, allowing us to reconstruct detailed PDFs. Comparisons with stellar parameter estimates from the literature show good agreement within uncertainties. We present UniDAM, the unified tool applicable to spectrophotometric data of different surveys, to obtain a homogenised set of stellar parameters.
21480. Unidentified cometary emission lines
ID:
ivo://CDS.VizieR/J/PAZh/30/946
Title:
Unidentified cometary emission lines
Short Name:
J/PAZh/30/946
Date:
21 Oct 2021
Publisher:
CDS
Description:
We discuss the possible nature of unidentified cometary emission lines. We propose a model of the ice particles in cometary halos as a mixture of frozen polycyclic aromatic hydrocarbons (PAHs) and acyclic hydrocarbons. We describe the general properties of frozen hydrocarbon particles (FHPs) and suggest interpreting some of the unidentified cometary emission lines as the photoluminescence of FHPs. We compare the position of quasi-lines in the spectrum of Comet 122P/de Vico with the position of quasi-lines in the photoluminescence spectrum of PAHs that were dissolved in acyclic hydrocarbons at a temperature of 77K and that constituted a polycrystalline solution. We estimated the detectability of FHP photoluminescence in cometary spectra.

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