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1401. Compiled photometry for Cham I and II members
ID:
ivo://CDS.VizieR/J/A+A/551/A46
Title:
Compiled photometry for Cham I and II members
Short Name:
J/A+A/551/A46
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a proper motion study aiming at providing further evidence on the origin of the proposed stellar members of the Chamaeleon I and II clouds and to identify interlopers from the foreground young clusters {epsilon} Cha and {eta} Cha. We compiled lists of spectroscopically confirmed members of the four associations, and of background objects in the same line of sight. Using Virtual Observatory tools, we cross-matched these lists with the UCAC3 (Cat. I/315) catalogue to get proper motions for the objects. In the vector point diagram, we identified the different moving groups, and used this information to study the membership of proposed candidate members of the associations from the literature. For those objects with available radial velocities, we computed their Galactic space velocities. We compiled photometry from public data archives and from the literature for the Cha I and II objects. We looked for correlations between the properties of the objects and their proper motions.
1402. Complex cluster Abell 1758 stars
ID:
ivo://CDS.VizieR/J/MNRAS/466/2614
Title:
Complex cluster Abell 1758 stars
Short Name:
J/MNRAS/466/2614
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a weak-lensing and dynamical study of the complex cluster Abell 1758 (A1758, {bar}z=0.278) supported by hydrodynamical simulations. This cluster is composed of two main structures called A1758N and A1758S. The northern structure is composed of A1758NW and A1758NE, with lensing determined masses of 7.90_-1.55_^+1.89^x10^14^M_{sun}_ and 5.49_-1.33_^+1.67^x10^14^M_{sun}_, respectively. They show a remarkable feature: while in A1758NW, there is a spatial agreement among weak-lensing mass distribution, intracluster medium and its brightest cluster galaxy (BCG), in A1758NE, the X-ray peak is located 96_-15_^+14^ arcsec away from the mass peak and BCG positions. Given the detachment between gas and mass, we could use the local surface mass density to estimate an upper limit for the dark matter self-interaction cross-section: {sigma}/m<5.83cm^2^/g. Combining our velocity data with hydrodynamical simulations, we have shown that A1758 NW and NE had their closest approach 0.27Gyr ago and their merger axis is 21+/-12{deg} from the plane of the sky. In the A1758S system, we have measured a total mass of 4.96_-1.19_^+1.08^x10^14^M_{sun}_ and, using radial velocity data, we found that the main merger axis is located at 70+/-4{deg} from the plane of the sky, therefore closest to the line of sight.
1403. Composite HST Spectrum of Quasars
ID:
ivo://CDS.VizieR/J/ApJ/475/469
Title:
Composite HST Spectrum of Quasars
Short Name:
J/ApJ/475/469
Date:
21 Oct 2021
Publisher:
CDS
Description:
We construct a composite quasar spectrum from 284 HST FOS spectra of 101 quasars with redshifts z>0.33. The spectrum covers the wavelengths between 350 and 3000A in the rest frame, with a peak S/N level of ~130 per A at ~1200A. Since ~90% of the sample quasars have redshift z<1.5, the spectrum is suitable for studying the wavelength region shortward of Ly{alpha} without large effects from intervening Ly{alpha} forest absorption. Data in the waveband between 350 and 600A are mainly from the spectra of z>1.5 quasars, for which significant corrections for the accumulated Lyman-series line and continuum absorption have been applied. There is a significant steepening of the continuum slope around 1050A. The continuum between 1050 and 2200A can be modeled as a power law f_{nu} proportional to {nu}_{alpha}_ with {alpha}=-0.99+/-0.05. For the full sample the power-law index in the extreme ultraviolet (EUV) between 350 and 1050A is {alpha}=-1.96+/-0.15. For the radio-loud subsample (60 objects), the EUV spectral index is {alpha}~=-2.2, while for the radio-quiet subsample (41 objects) it is {alpha}~=-1.8. The continuum flux in the wavelengths near the Lyman limit shows a depression of ~10%. The break in the power-law index and the slight depression of the continuum near the Lyman limit are features expected in Comptonized accretion-disk spectra. Comptonization produces a power-law tail in the wavelength band shortward of 1000A and smears out the Lyman-limit edge of the intrinsic accretion-disk spectrum. In the EUV waveband, we detect several possible emission features, including one around 690A that may be O III + N III produced by the Bowen fluorescence effect. Comparing our composite spectrum with one made at higher redshifts by Francis et al. (1991ApJ...373..465F), we find that the equivalent widths of Ly{alpha} and high-ionization emission lines are larger in our sample, reflecting a known luminosity dependence. The equivalent widths of low-ionization lines do not exhibit such a dependence, suggesting that the quasar EUV continuum above ~50eV is steeper at higher luminosity. Radio-quiet quasars appear to show a slightly harder continuum and lower ionization levels in their emission lines.
1404. Composite spectra of early-type galaxies
ID:
ivo://CDS.VizieR/J/AJ/131/1288
Title:
Composite spectra of early-type galaxies
Short Name:
J/AJ/131/1288
Date:
21 Oct 2021
Publisher:
CDS
Description:
Chemical abundance indicators are studied using composite spectra, which we provide in tabular form. Tables of line strengths measured from these spectra and parameters derived from these line strengths are also provided. All the objects we analyze were selected from the SDSS database. We selected all objects targeted as galaxies and having Petrosian apparent magnitude 14.5<=r_Pet_<=17.75. To extract a sample of early-type galaxies, we then chose the subset with the spectroscopic parameter eclass<0, which classifies the spectral type based on a principal component analysis, and the photometric parameter fracDev_r_>0.8, which is a seeing-corrected indicator of morphology.
1405. Computed Hbeta indices from ATLAS9 model
ID:
ivo://CDS.VizieR/J/A+A/454/333
Title:
Computed Hbeta indices from ATLAS9 model
Short Name:
J/A+A/454/333
Date:
21 Oct 2021
Publisher:
CDS
Description:
Grids of H{beta} indices based on updated (new-ODF) ATLAS9 model atmospheres were computed for solar and scaled solar metallicities [+0.5], [+0.2], [0.0], [-0.5], [-1.0], [-1.5], [-2.0], [-2.5] and for alpha enhanced compositions [+0.5a], [0.0a], [-0.5a], [-1.0a], [-1.5a], [-2.0a], [-2.5a], and [-4.0a]. Indices for Teff>5000K were computed with the same methods as described by Lester, Gray & Kurucz (1986ApJS...61..509L) (LGK86) except for a different normalization of the computed natural system to the standard system. LGK86 used special ODFs to compute the fluxes. For Teff less or equal to 5000K we computed the fluxes using the synthetic spectrum method. In order to assess the accuracy of the computed indices comparisons were made with the indices computed by Smalley & Dworetsky (1995A&A...293..446S) (MD95) and with the empirical relations Teff-H{beta} given by Alonso et al. (1996A&A...313..873A) for several metallicities. Furthermore, for cool stars, temperatures inferred from the computed indices were compared with those of the fundamental stars listed by MD95. The same kind of comparison was made between gravities for B-type stars. The temperatures from the computed indices are in good agreement, within the error limits, with the literature values for Teff between 4750K and 8000K, while the gravities agree for Teff>9000K. The computed H{beta} indices for the Sun and for Procyon are very close to the observed values. The comparison between the observed and computed H{beta} indices as function of the observed H{beta} has shown a very small trend which almost completely disappears when only stars hotter than 10000K are considered. The trend due to the cool stars is probably related with the low accuracy of the fundamental Teff which are affected by large errors for most of the stars.
1406. CONCH-SHELL catalog of nearby M dwarfs
ID:
ivo://CDS.VizieR/J/MNRAS/443/2561
Title:
CONCH-SHELL catalog of nearby M dwarfs
Short Name:
J/MNRAS/443/2561
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an all-sky catalogue of 2970 nearby (d<~50pc), bright (J<9) M- or late K-type dwarf stars, 86% of which have been confirmed by spectroscopy. This catalogue will be useful for searches for Earth-size and possibly Earth-like planets by future space-based transit missions and ground-based infrared Doppler radial velocity surveys. Stars were selected from the SUPERBLINK proper motion catalogue (Cat. I/298) according to absolute magnitudes, spectra, or a combination of reduced proper motions and photometric colours. From our spectra, we determined gravity-sensitive indices, and identified and removed 0.2% of these as interloping hotter or evolved stars. 13% of the stars exhibit H{alpha} emission, an indication of stellar magnetic activity and possible youth. The mean metallicity is [Fe/H]=-0.07 with a standard deviation of 0.22dex, similar to nearby solar-type stars. We determined stellar effective temperatures by least-squares fitting of spectra to model predictions calibrated by fits to stars with established bolometric temperatures, and estimated radii, luminosities, and masses using empirical relations. 6% of stars with images from integral field spectra are resolved doubles. We inferred the planet population around M dwarfs using Kepler data and applied this to our catalogue to predict detections by future exoplanet surveys.
1407. CoNFIG AGN sample
ID:
ivo://CDS.VizieR/J/MNRAS/430/3086
Title:
CoNFIG AGN sample
Short Name:
J/MNRAS/430/3086
Date:
21 Oct 2021
Publisher:
CDS
Description:
The goal of this work is to determine the nature of the relation between morphology and accretion mode in radio galaxies, including environmental parameters. The CoNFIG extended catalogue (improved by new K_S_-band identifications and estimated redshifts from UKIRT Infrared Deep Sky Survey (UKIDSS), and spectral index measurements from new GMRT observations) is used to select a sub-sample of 206 radio galaxies with z<=0.3 over a wide range of radio luminosity, which are morphology-classified using the Fanaroff-Riley (FR) classification of extended radio sources. For each galaxy, spectroscopic data are retrieved to determine the high/low excitation status of the source, related to its accretion mode. Environmental factors, such as the host galaxy luminosity and a richness factor, are also computed, generally using the Sloan Digital Sky Survey data.
1408. Confirmed members of RX J0152.7-1357
ID:
ivo://CDS.VizieR/J/ApJ/725/1252
Title:
Confirmed members of RX J0152.7-1357
Short Name:
J/ApJ/725/1252
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a spectrophotometric analysis of galaxies belonging to the dynamically young, massive cluster RX J0152.7-1357 at z~0.84, aimed at understanding the effects of the cluster environment on the star formation history (SFH) of cluster galaxies and the assembly of the red sequence (RS). We use VLT/FORS spectroscopy, ACS/WFC optical, and NTT/SofI near-IR data to characterize SFHs as a function of color, luminosity, morphology, stellar mass, and local environment from a sample of 134 spectroscopic members. In order to increase the signal-to-noise ratio, individual galaxy spectra are stacked according to these properties. Moreover, the D4000, Balmer, CN3883, Fe4383, and C4668 indices are also quantified.
1409. Constant Stars in the GCVS. II.
ID:
ivo://CDS.VizieR/J/PASP/108/1105
Title:
Constant Stars in the GCVS. II.
Short Name:
J/PASP/108/1105
Date:
21 Oct 2021
Publisher:
CDS
Description:
Photometric observations have been made of 36 stars classified as CST or CST: in the General Catalogue of Variable Stars. Six of these stars are found to vary and three others were deemed possible variables. Of the certain variables, two (MR Her and TY Sge) are red pulsators, one (V1585 Cyg) is a rapid irregular variable, one is apparently a short period Cepheid-strip star (V432 Oph), one is an eclipsing binary (AQ Boo) and one is uncertain type (V351 Cyg). The stars we have observed as MR Her and TY Sge are the same ones which were identified on finding charts in the discovery papers suggesting that these stars have intervals of variability and intervals of quiescence. V432 Oph is of special interest because our photometry indicates that it may be either a double mode Cepheid or a peculiar long period RR Lyrae star depending on which of a couple of possible periods turns out to be correct.
1410. 9380 contact binaries from CRTS VSC
ID:
ivo://CDS.VizieR/J/MNRAS/465/4678
Title:
9380 contact binaries from CRTS VSC
Short Name:
J/MNRAS/465/4678
Date:
21 Oct 2021
Publisher:
CDS
Description:
We construct a sample of 9380 contact binaries (W UMa systems) by using the Catalina Real-Time Transient Survey Variables Sources Catalogue. By measuring brightness change rates, light-curve statistics, and temperatures for this sample, we improve the understanding of contact binary light-curve characteristics, and luminosity variability on decadal time-scales. We show that binaries with convective outer envelopes have a different distribution of light-curve amplitudes and magnitude differences between eclipse minima than binaries with radiative outer envelopes. We find that more than 2000 binaries exhibit a linear change in mean brightness over the 8-yr timespan of observations with at least 3{sigma} significance. We note that 25.9 per cent of binaries with convective outer envelopes exhibit a significant change in brightness, while only 10.5 per cent of radiative binaries exhibit a significant change in brightness. In 205 binaries (2.2 per cent), we find that a sinusoid model better describes the luminosity trend within the 8-yr observation timespan. For these binaries, we report the amplitudes and periods (as estimated using observed half-periods) of this sinusoidal brightness variation and discuss possible mechanisms driving the variation.