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2281. Narrowband Ca photometry for dwarf spheroidal galaxies
ID:
ivo://CDS.VizieR/J/ApJS/247/7
Title:
Narrowband Ca photometry for dwarf spheroidal galaxies
Short Name:
J/ApJS/247/7
Date:
21 Oct 2021
Publisher:
CDS
Description:
A few dozen dwarf satellite galaxies of the Milky Way have been discovered, which are often viewed as the remaining building blocks of our Galaxy. The follow-up spectroscopy showed that dwarf galaxies have a sizeable spread in their metallicities. Several scenarios were suggested to explain the metallicity spread, which can be tested by the structural patterns of stellar subpopulations with distinct metallicities. However, such chemical plus structural examination, which we refer to as "chemostructural study", is hindered by the lack of stars with spectroscopic metallicity. Here we propose the Ca-by photometry as an alternative way to secure metallicities for a 2-3 orders of magnitude larger stellar sample than the spectroscopic sample and thus enable us to perform a chemostructural study on dwarf galaxies. In particular, we use the hk index [=(Ca-b)-(b-y)], whose validity as a photometric metallicity indicator (and crass insensitivity to age) for red-giant-branch stars was upheld via Galactic globular clusters, and observe three dwarf spheroidal galaxies-Draco, Sextans, and Canes Venatici I (CVnI)-with Subaru/Suprime-Cam. We find that in all the galaxies the metal-rich stellar populations are more centrally concentrated than the metal-poor counterparts, suggesting that the central regions of the galaxies underwent extended star formation. Such a negative radial metallicity gradient for Sextans and CVnI opposes the traditional spectroscopic results. We also find that their metallicity distribution functions (MDFs) can be characterized by a unimodal, skewed Gaussian shape with a metal-rich peak and a metal-poor tail.
2282. 2nd Cat. of Radial Velocities with Astrometric Data
ID:
ivo://CDS.VizieR/III/254
Title:
2nd Cat. of Radial Velocities with Astrometric Data
Short Name:
III/254
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalogue of radial velocities of Galactic stars with high precision astrometric data, 2nd version (CRVAD-2), is the result of a merging of star lists from the All-Sky Compiled Catalogue of 2.5 Million Stars (ASCC-2.5, Cat. I/280) with the General Catalogue of Radial Velocities (GCRV, Cat. III/213) and with other recently published radial velocity lists and catalogues. Cross identification of objects was carried out with help of coordinate, magnitude, colour and/or spectral type criteria. Data from the Catalogue of Components of Double and Multiple Stars (CCDM, Cat. I/274) were taken into account for the identification of multiple system components. Altogether 54907 stars from the ASCC-2.5 were identified with 51762 stars from the RV source catalogues, 3085 stars have secondary components and 30 stars have 3rd components in multiple systems. The CRVAD-2 includes accurate J2000 equatorial coordinates, proper motions and trigonometric parallaxes in the Hipparcos system, Johnson's BV photometric data, spectral types, radial velocities, multiplicity and variability flags. Stars are sorted in the order of increasing right ascension J2000. This catalogue supersedes the previous version numbered <III/239>.
2283. Nearby early-type galaxies in Stripe 82
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.
2284. Nearby globular clusters photometric catalog
ID:
ivo://CDS.VizieR/J/A+AS/144/5
Title:
Nearby globular clusters photometric catalog
Short Name:
J/A+AS/144/5
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first part of the first large and homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands using only two telescopes (one for each hemisphere). The observed clusters represent 75% of the known Galactic globulars with (m-M)V<=16.15mag, cover most of the globular cluster metallicity range (-2.2<=[Fe/H]<=-0.4), and span Galactocentric distances from ~1.2 to ~18.5kpc. In this paper, the CMDs for the 39 GGCs observed in the southern hemisphere are presented. The remaining 13 northern hemisphere clusters of the catalog are presented in a companion paper. For four clusters (NGC 4833, NGC 5986, NGC 6543, and NGC 6638) we present for the first time a CMD from CCD data. The typical CMD span from the 22^nd^ V magnitude to the tip of the red giant branch. Based on a large number of standard stars, the absolute photometric calibration is reliable to the ~0.02mag level in both filters. This catalog, because of its homogeneity, is expected to represent a useful data base for the measurement of the main absolute and relative parameters characterizing the CMD of GGCs.
2285. Nearby globular clusters photometric catalog
ID:
ivo://CDS.VizieR/J/A+AS/145/451
Title:
Nearby globular clusters photometric catalog
Short Name:
J/A+AS/145/451
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we present the second and final part of a large and photometrically homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands. The catalog has been collected using only two telescopes (one for each hemisphere).
2286. Nearby low-mass stars proper motions
ID:
ivo://CDS.VizieR/J/ApJ/862/173
Title:
Nearby low-mass stars proper motions
Short Name:
J/ApJ/862/173
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper uses the multi-epoch astrometry from the Wide-field Infrared Survey Explorer (WISE) to demonstrate a method to measure proper motions and trigonometric parallaxes with precisions of ~4mas/yr and ~7mas, respectively, for low-mass stars and brown dwarfs. This method relies on WISE single exposures (Level 1b frames) and a Markov Chain Monte Carlo method. The limitations of Gaia in observing very low-mass stars and brown dwarfs are discussed, and it is shown that WISE will be able to measure astrometry past the 95% completeness limit and magnitude limit of Gaia (L, T, and Y dwarfs fainter than G~=19 and G=21, respectively). This method is applied to WISE data of 20 nearby (<=17pc) dwarfs with spectral types between M6-Y2 and previously measured trigonometric parallaxes. Also provided are WISE astrometric measurements for 23 additional low-mass dwarfs with spectral types between M6-T7 and estimated photometric distances <17pc. Only nine of these objects contain parallaxes within Gaia Data Release 2.
2287. Nearby massive early-type galaxies from MATLAS
ID:
ivo://CDS.VizieR/J/MNRAS/498/2138
Title:
Nearby massive early-type galaxies from MATLAS
Short Name:
J/MNRAS/498/2138
Date:
12 Jan 2022 05:42:10
Publisher:
CDS
Description:
The morphology of galaxies gives essential constraints on the models of galaxy evolution. The morphology of the features in the low-surface-brightness (LSB) regions of galaxies has not been fully explored yet because of observational difficulties. Here we present the results of our visual inspections of very deep images of a large volume-limited sample of 177 nearby massive early-type galaxies from the MATLAS survey. The images reach a surface-brightness limit of 28.5-29mag/arcsec^2^ in the g' band. Using a dedicated navigation tool and questionnaire, we looked for structures at the outskirts of the galaxies such as tidal shells, streams, tails, disturbed outer isophotes, or peripheral star-forming discs, and simultaneously noted the presence of contaminating sources, such as Galactic cirrus. We also inspected internal substructures such as bars and dust lanes. We discuss the reliability of this visual classification investigating the variety of answers made by the participants. We present the incidence of these structures and the trends of the incidence with the mass of the host galaxy and the density of its environment. We find an incidence of shells, stream, and tails of approximately 15%, about the same for each category. For galaxies with masses over 10^11^M_{sun}_, the incidence of shells and streams increases about 1.7 times. We also note a strong unexpected anticorrelation of the incidence of Galactic cirrus with the environment density of the target galaxy. Correlations with other properties of the galaxies, and comparisons to model predictions, will be presented in future papers.
2288. 24 nearby open clusters TGAS and HSOY reanalysis
ID:
ivo://CDS.VizieR/J/A+A/615/A12
Title:
24 nearby open clusters TGAS and HSOY reanalysis
Short Name:
J/A+A/615/A12
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have determined stellar membership based on astrometry, primarily from TGAS and HSOY, and multi-band photometry for 24 clusters within 333 pc. The fundamental cluster parameters (distance, age, and reddening) have been derived by fitting Padova isochrones (Bressan et al. 2012) to the cluster photometry using a chi-squared minimization.
2289. Nearby radio galaxies FUV to MIR properties
ID:
ivo://CDS.VizieR/J/A+A/581/A33
Title:
Nearby radio galaxies FUV to MIR properties
Short Name:
J/A+A/581/A33
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate whether the far-UV continuum of nearby radio galaxies is due solely to the parent galaxy that passively evolves, or if it reveals evidence for the presence of other star-forming or non-stellar components. If the UV excess is due to an additional radiation component, we compare this with other properties such as radio power, optical spectral type (e.g. high- and low-excitation galaxies), and the strength of the emission lines. We also discuss the possible correlation between the ultraviolet flux, IR properties, and the central black hole mass. We used a sample of low-luminosity B2 radio galaxies and a small sample of higher luminosity 3C radio galaxies at comparable redshift (z<0.2). Spectral energy distributions (SEDs) were constructed using a number of on-line databases that are freely available now: GALEX, SDSS, 2MASS, and WISE. These were compared with model SEDs of early-type galaxies with passively evolving stellar populations at various ages (typically 0.5-1.3x10^9^ years). We established whether a second component was needed to obtain a satisfactory fit with the observed overall SED. We introduce the parameter XUV, which measures the excess slope of the UV continuum between 4500 and 2000{AA} with respect to the UV radiation produced by the underlying old galaxy component. We find that the UV excess as measured by XUV is usually small or absent in low-luminosity (FR I) sources, but sets in abruptly at the transition radio power, above which we find mostly FRII sources. XUV behaves very similarly to the strength of the optical emission lines (in particular H{alpha}). Below P_1.4GHz_<10^24^W/Hz XUV is close to zero. XUV correlates strongly with the H{alpha} line strength, but only in sources with strong H{alpha} emission. We discuss whether the line emission might be due to photoionization by radiation from the parent galaxy, possibly with additional star formation, or if it requires the presence of a non-stellar active galactic nucleus component. XUV and the slope of the mid-IR are strongly correlated, as measured by the WISE bands in the interval 3.4 to 22{mu}m, in the sense that sources with a strong UV excess also have stronger IR emission. There is an inverse correlation between XUV and central black hole mass: the M_BH_ of objects with strong UV excess is on average two to three times less massive than that of objects without UV excess. Low-luminosity radio galaxies tend to be more massive and contain more massive black holes.
2290. Nearby stars in the NLTT catalogue
ID:
ivo://CDS.VizieR/J/AJ/123/2806
Title:
Nearby stars in the NLTT catalogue
Short Name:
J/AJ/123/2806
Date:
21 Oct 2021
Publisher:
CDS
Description:
We are currently undertaking a program aimed at identifying previously unrecognized late-type dwarfs within 20pc of the Sun. As a first step, we have cross-referenced Luyten's NLTT proper-motion catalog (Cat. <I/98>) against the second incremental release of the Two Micron All Sky Survey (2MASS) Point Source Catalog (Cat. <B/2mass>) and use optical/infrared colors, derived by combining Luyten's m_r_ estimates with 2MASS data, to identify candidate nearby stars. This paper describes the definition of a reference sample of 1245 stars and presents a compilation of literature data for more than one-third of the sample. Only 274 stars have trigonometric parallax measurements, but we have used data for nearby stars with well-determined trigonometric parallaxes to compute color-magnitude relations in the (M_V_, V-K), (M_V_, V-I), and (M_I_, I-J) planes and use those relations to determine photometric parallaxes for NLTT stars with optical photometry. Based on the 2MASS JHKs data alone, we have identified a further 42 ultracool dwarfs (J-Ks>0.99) and use J-Ks colors to estimate photometric parallaxes. Combining these various techniques, we identify 308 stars with formal distances of less than 20 pc, while a further 46 have distance estimates within 1{sigma} of survey limit. Of these 354 stars, 75, including 39 of the ultracool dwarfs, are new to nearby-star catalogs. Two stars with both optical and near-infrared photometry are potential additions to the immediate solar neighborhood, with formal distance estimates of less than 10 pc.