- 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.
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- ID:
- ivo://CDS.VizieR/J/A+A/620/A111
- Title:
- Confirmed PN in M87 outer regions
- Short Name:
- J/A+A/620/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a kinematic study of a sample of 298 planetary nebulas (PNs) in the outer halo of the central Virgo galaxy M87 (NGC 4486). The line-of-sight velocities of these PNs are used to identify sub-components, to measure the angular momentum content of the main M87 halo, and to constrain the orbital distribution of the stars at these large radii. We use Gaussian mixture modelling to statistically separate distinct velocity components and identify the M87 smooth halo component, its unrelaxed substructures, and the intra-cluster (IC) PNs. We compute probability weighted velocity and velocity dispersion maps for the smooth halo, and its specific angular momentum profile ({lambda}_R_) and velocity dispersion profile. The classification of the PNs into smooth halo and ICPNs is supported by their different PN luminosity functions. Based on a K-S test, we conclude that the ICPN line-of-sight velocity distribution (LOSVD) is consistent with the LOSVD of the galaxies in Virgo subcluster A. The surface density profile of the ICPNS at 100kpc radii has a shallow logarithmic slope, -{alpha}_ICL_~=-0.8, dominating the light at the largest radii. Previous B-V colour and resolved star metallicity data indicate masses for the ICPN progenitor galaxies of a few x10^8^M_{sun}_. The angular momentum-related {lambda}_R_ profile for the smooth halo remains below 0.1, in the slow rotator regime, out to 135kpc average ellipse radius (170kpc major axis distance). Combining the PN velocity dispersion measurements for the M87 halo with literature data in the central 15kpc, we obtain a complete velocity dispersion profile out to R_avg_=135kpc. The {sigma}_halo_ profile decreases from the central 400km/s to about 270km/s at 2-10kpc, then rises again to ~=300+/-50km/s at 50-70kpc to finally decrease sharply to {sigma}_halo_~100km/s at R_avg_=135kpc. The steeply decreasing outer {sigma}_halo_ profile and the surface density profile of the smooth halo can be reconciled with the circular velocity curve inferred from assuming hydrostatic equilibrium for the hot X-ray gas. Because this rises to v_c,X_~700km/s at 200kpc, the orbit distribution of the smooth M87 halo is required to change strongly from approximately isotropic within R_avg_~60kpc to very radially anisotropic at the largest distances probed. The extended LOSVD of the PNs in the M87 halo allows the identification of several subcomponents: the ICPNs, the "crown" accretion event, and the smooth M87 halo. In galaxies likeM87, the presence of these sub-components needs to be taken into account to avoid systematic biases in estimating the total enclosed mass. The dynamical structure inferred from the velocity dispersion profile indicates that the smooth halo of M87 steepens beyond Ravg=60kpc and becomes strongly radially anisotropic, and that the velocity dispersion profile is consistent with the X-ray circular velocity curve at these radii without non-thermal pressure effects.
- 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.
- ID:
- ivo://CDS.VizieR/VI/49
- Title:
- Constellation Boundary Data
- Short Name:
- VI/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A computer readable catalog of constellation boundary data is presented in a form suitable for the construction of star charts and atlases. Two data files are available, one for equator and equinox 1875 and the other for equator and equinox 2000. In addition to the data files a documentation file is available that includes a table listing the abbreviations used for the constellations as well as a more detailed discussion of the preparation of the catalog. The present catalog of constellation boundary data is complementary to that of Roman (1987). Roman's catalog should be used to determine in which constellation an object lies in. The present catalog is more suited to the construction of star charts and atlases. Both catalogs were based on Delporte (1930).
- ID:
- ivo://CDS.VizieR/J/A+A/608/A46
- Title:
- Constraining cosmic scatter
- Short Name:
- J/A+A/608/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the stellar parameters, abundances, associated errors and the linelist of a set of 23 metal-poor and very metal-poor halo stars. Stellar parameters and chemical abundances were derived in a line-by-line differential analysis from equivalent widths of UVES/VLT spectra. The differential analysis provided us unprecedented small data scatter and errors. Our sample, along with data from different authors in different metallicity ranges, allowed us to do an extensive comparison of the chemical abundances with the predictions of a Galaxy chemical evolution model.
- ID:
- ivo://CDS.VizieR/J/ApJ/834/49
- Title:
- Constraining the epoch of reionization
- Short Name:
- J/ApJ/834/49
- Date:
- 09 Feb 2022 14:54:48
- Publisher:
- CDS
- Description:
- We combine observational data on a dozen independent cosmic properties at high-z with the information on reionization drawn from the spectra of distant luminous sources and the cosmic microwave background (CMB) to constrain the interconnected evolution of galaxies and the intergalactic medium since the dark ages. The only acceptable solutions are concentrated in two narrow sets. In one of them reionization proceeds in two phases: a first one driven by Population III stars, completed at z~10, and after a short recombination period a second one driven by normal galaxies, completed at z~6. In the other set both kinds of sources work in parallel until full reionization at z~6. The best solution with double reionization gives excellent fits to all the observed cosmic histories, but the CMB optical depth is 3{sigma} larger than the recent estimate from the Planck data. Alternatively, the best solution with single reionization gives less good fits to the observed star formation rate density and cold gas mass density histories, but the CMB optical depth is consistent with that estimate. We make several predictions, testable with future observations, that should discriminate between the two reionization scenarios. As a byproduct our models provide a natural explanation to some characteristic features of the cosmic properties at high-z, as well as to the origin of globular clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A116
- Title:
- Constraints on the progenitor of SN 1987A
- Short Name:
- J/A+A/624/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the same method as used previously, we investigate neutrino-driven explosions of a larger sample of blue supergiant models. The blue supergiants were evolved as single-star progenitors. The larger sample includes three new presupernova stars. The results are compared with light-curve observations of the peculiar type IIP SN 1987A. The explosions were modeled in 3D with the neutrino-hydrodynamics code PROMETHEUS-HOTB, and light-curve calculations were performed in spherical symmetry with the radiation-hydrodynamics code CRAB, starting at a stage of nearly homologous expansion. Our results confirm the basic findings of the previous work: 3D neutrino-driven explosions with SN 1987A-like energies synthesize an amount of Ni-56 that is consistent with the radioactive tail of the light curve. Moreover, the models mix hydrogen inward to minimum velocities below 400km/s as required by spectral observations and a 3D analysis of molecular hydrogen in SN 1987A. Hydrodynamic simulations with the new progenitor models, which possess smaller radii than the older ones, show much better agreement between calculated and observed light curves in the initial luminosity peak and during the first 20 days. A set of explosions with similar energies demonstrated that a high growth factor of Rayleigh-Taylor instabilities at the (C+O)/He composition interface combined with a weak interaction of fast Rayleigh-Taylor plumes, where the reverse shock occurs below the He/H interface, provides a sufficient condition for efficient outward mixing of Ni-56 into the hydrogen envelope. This condition is realized to the required extent only in one of the older stellar models, which yielded a maximum velocity of around 3000km/s for the bulk of ejected Ni-56, but failed to reproduce the helium-core mass of 6M_{sun}_ inferred from the absolute luminosity of the presupernova star. We conclude that none of the single-star progenitor models proposed for SN 1987A to date satisfies all constraints set by observations.
- 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.
- ID:
- ivo://CDS.VizieR/J/AcA/51/259
- Title:
- Contact binaries in OGLE-I database
- Short Name:
- J/AcA/51/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present catalog contains the most numerous, observationally homogeneous sample of contact binaries. It is derived from the OGLE experiment (Optical Gravitational Lensing Experiment), in the direction of the Galactic Bulge and the Galactic bar. The observations were made with the 1-m Swope telescope at Las Campanas Observatory in Chile, over the period 1992 to 1995. The present catalog includes the 1575 newly discovered contact binaries fainter than I=18mag as well as the 1165 brighter contact binaries previously published. It also includes a list of 506 objects with nearly sinusoidal light curves, to ease the comparison and/or distinction between contact binaries with the sinusoidal light curves and pulsating stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/507/4914
- Title:
- Contact-binary (68346) 2001 KZ66 light curves
- Short Name:
- J/MNRAS/507/4914
- Date:
- 19 Jan 2022 09:12:40
- Publisher:
- CDS
- Description:
- The YORP effect is a small thermal-radiation torque experienced by small asteroids, and is considered to be crucial in their physical and dynamical evolution. It is important to understand this effect by providing measurements of YORP for a range of asteroid types to facilitate the development of a theoretical framework. We are conducting a long-term observational study on a selection of near-Earth asteroids to support this. We focus here on (68346) 2001 KZ66, for which we obtained both optical and radar observations spanning a decade. This allowed us to perform a comprehensive analysis of the asteroid's rotational evolution. Furthermore, radar observations from the Arecibo Observatory enabled us to generate a detailed shape model. We determined that (68346) is a retrograde rotator with its pole near the southern ecliptic pole, within a 15-degree radius of longitude 170 degrees and latitude -85-degrees. By combining our radar-derived shape model with the optical light curves we developed a refined solution to fit all available data, which required a YORP strength of (8.43+/-0.69)x10^-8^rad/day/day. (68346) has a distinct bifurcated shape comprising a large ellipsoidal component joined by a sharp neckline to a smaller non-ellipsoidal component. This object likely formed from either the gentle merging of a binary system, or from the deformation of a rubble pile due to YORP spin-up. The shape exists in a stable configuration close to its minimum in topographic variation, where regolith is unlikely to migrate from areas of higher potential.