Search

Start Over Subject optical astronomy
3631. Structure of the Upper Scorpius association
ID:
ivo://CDS.VizieR/J/MNRAS/477/L50
Title:
Structure of the Upper Scorpius association
Short Name:
J/MNRAS/477/L50
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using new proper motion data from recently published catalogs, we revisit the membership of previously identified members of the Upper Scorpius association. We confirmed 750 of them as cluster members based on the convergent point method, compute their kinematic parallaxes and combined them with Gaia parallaxes to investigate the 3D structure and geometry of the association using a robust covariance method. We find a mean distance of 146+/-3+/-6pc and show that the morphology of the association defined by the brightest (and most massive) stars yields a prolate ellipsoid with dimensions of 74x38x32pc^3^, while the faintest cluster members define a more elongated structure with dimensions of 98x24x18pc^3^. We suggest that the different properties of both populations is an imprint of the star formation history in this region.
3632. Structures in the GA region
ID:
ivo://CDS.VizieR/J/MNRAS/369/1131
Title:
Structures in the GA region
Short Name:
J/MNRAS/369/1131
Date:
21 Oct 2021
Publisher:
CDS
Description:
To further our understanding of the Great Attractor (GA), we have undertaken a redshift survey using the 2dF on the AAT. Clusters and filaments in the GA region were targeted with 25 separate pointings resulting in approximately 2600 new redshifts. Targets included poorly studied X-ray clusters from the CIZA catalogue as well as the Cen-Crux and PKS 1343-601 clusters, both of which lie close to the classic GA centre. For nine clusters in the region, we report velocity distributions as well as virial and projected mass estimates. The virial mass of CIZA J1324.75736, now identified as a separate structure from the Cen-Crux cluster, is found to be ~3x10^14^M_{sun}_ in good agreement with the X-ray inferred mass. In the PKS 1343-601 field, five redshifts are measured of which four are new. An analysis of redshifts from this survey, in combination with those from the literature, reveals the dominant structure in the GA region to be a large filament, which appears to extend from Abell S0639 (l=281{deg}, b=+11{deg}) to (l~5{deg}, b~-50{deg}), encompassing the Cen-Crux, CIZA J1324.75736, Norma and Pavo II clusters. Behind the Norma Cluster at cz~15000km/s, the masses of four rich clusters are calculated. These clusters (Triangulum-Australis, Ara, CIZA J1514.64558 and CIZA J1410.44246) may contribute to a continued large- scale flow beyond the GA. The results of these observations will be incorporated into a subsequent analysis of the GA flow.
3633. STScI Office of Public Outreach Authority Name
ID:
ivo://opo.stsci
Title:
STScI Office of Public Outreach Authority Name
Short Name:
opo.stsci
Date:
04 Apr 2008 16:07:41
Publisher:
Office of Public Outreach, Space Telescope Science Institute
Description:
This authority name is used to identify resource from the STScI Office of Public Outreach.
3634. Studies of Bright Steep-Spectrum Radio Sources
ID:
ivo://CDS.VizieR/J/AZh/77/3
Title:
Studies of Bright Steep-Spectrum Radio Sources
Short Name:
J/AZh/77/3
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results of studies of bright radio sources in the constellation Cetus are presented. More than 50% of the sources have radio spectral indices steeper than 0.9. Optical identifications have been determined for 35 sources. A large fraction of the radio sources are identified with weak blue galaxies. Given their spectral indices, it is likely that these objects have redshift z=0.4-1.0. More than 20% of the steep-spectrum sources do not have optical identifications and appear to be weak galaxies with z>2.
3635. Studies of LMC stellar content
ID:
ivo://CDS.VizieR/III/147
Title:
Studies of LMC stellar content
Short Name:
III/147
Date:
21 Oct 2021
Publisher:
CDS
Description:
A spectral survey has been made during the period 1971 to 1975 with the ESO 40cm astrograph at La Silla, equipped with its normal prism, giving an intermediate dispersion of 95Angstroem/mm at 4026Angstroem. Long exposure plates taken directly or with an interference filter enabled us to obtain spectral types for nearly 1600 stars. In parallel, a V photographic survey has been carried out during the same period with the same astrograph and has led to the determination of V magnitudes for more that 700 stars having no previous photometric data. New spectroscopic and photometric results as well as previous photoelectric UBV values are given in the catalogue together with additional remarks concerning peculiarities of spectra, V magnitudes, and details on double and multiple systems.
3636. Study of bars in 180 spiral galaxies
ID:
ivo://CDS.VizieR/J/ApJ/659/1176
Title:
Study of bars in 180 spiral galaxies
Short Name:
J/ApJ/659/1176
Date:
21 Oct 2021
Publisher:
CDS
Description:
Critical insights on galaxy evolution stem from the study of bars. With the advent of HST surveys that trace bars in the rest-frame optical out to z~1, it is critical to provide a reference baseline for bars at z~0 in the optical band. We present results on bars at z~0 in the optical and NIR based on 180 spirals from OSUBSGS (Eskridge et al., 2002, Cat. J/ApJS/143/73).
3637. Study of FK Comae Berenices. IV.
ID:
ivo://CDS.VizieR/J/A+A/390/179
Title:
Study of FK Comae Berenices. IV.
Short Name:
J/A+A/390/179
Date:
21 Oct 2021
Publisher:
CDS
Description:
Doppler imaging techniques have earlier been used to study the starspots and their evolution over a four year period in a single, late-type star FK Com. In the present work we publish new photometric observations of FK Com for the year 2001 and analyse them together with the previously published photometry obtained since 1966. The observations for 2001 have been carried out at the Phoenix 10 automatic photometric telescope in Arizona, USA. Observations contain measurements at the Johnson U, B and V bands. The observations are differential photometry in respect to the primary comparison star HD 117567. In table1, 99.000 means that no observations were available at that time at that band or that the error in the magnitude was larger than 0.02.
3638. Study of PGC-54-like galaxies
ID:
ivo://CDS.VizieR/J/other/ChA+A/34.367
Title:
Study of PGC-54-like galaxies
Short Name:
J/other/ChA+A/34
Date:
21 Oct 2021
Publisher:
CDS
Description:
With the improved Peng's method, we have made the image processing and spiral arm fitting of the newly released spiral galactic images of Sloan Digital Sky Survey (SDSS), and obtained the equivalent thicknesses of galactic disks, as well as the tangential angles of spiral arms of 73 spiral galaxies. These physical quantities are very important for future studies on the properties of spiral galaxies.
3639. Study of three early-type contact twin binaries
ID:
ivo://CDS.VizieR/J/AJ/157/111
Title:
Study of three early-type contact twin binaries
Short Name:
J/AJ/157/111
Date:
21 Oct 2021
Publisher:
CDS
Description:
Three eclipsing binaries, CT Tau, GU Mon, and V701 Sco, are early-type contact binaries with infrared excess from circumbinary matter. We present the multi-color photometry for CT Tau and GU Mon, whose spectral types of B1V are identified by the low-precision spectra. Combining these new light curves (LCs) with previously reported LCs and radial velocity curves, we perform a synthesized analysis to estimate/update the stellar absolute parameters of the three systems. Their mass ratios are close to unity (i.e., q~1), which indicates that the binary system comprising of twin components may be undergoing a slow Case A mass transfer. From the period analysis, the light-time orbit in the (O-C) curve may result from the third condense companion around the binary system although no evidence could be provided by the third light l_3_. From the spectral energy distribution for three binaries, the excess infrared (IR) emissions are above the photospheric emissions, which can be seen at the 22.1 {mu}m for CT Tau and GU Mon, and 11.6 {mu}m, 14.5 {mu}m, and 22.1 {mu}m for V701 Sco, respectively. This kind of infrared excess for the early-type star may be attributed to the circumbinary matter by stellar wind.
3640. S-type AGB stars in SMC
ID:
ivo://CDS.VizieR/J/ApJ/810/116
Title:
S-type AGB stars in SMC
Short Name:
J/ApJ/810/116
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have identified a new class of Asymptotic Giant Branch (AGB) stars in the Small and Large Magellanic Clouds (SMC/LMC) using optical to infrared photometry, light curves, and optical spectroscopy. The strong dust production and long-period pulsations of these stars indicate that they are at the very end of their AGB evolution. Period-mass-radius relations for the fundamental-mode pulsators give median current stellar masses of 1.14M_{sun}_ in the LMC and 0.94M_{sun}_ in the SMC (with dispersions of 0.21 and 0.18M_{sun}_, respectively), and models suggest initial masses of <1.5M_{sun}_ and <1.25 M_{sun}_, respectively. This new class of stars includes both O-rich and C-rich chemistries, placing the limit where dredge-up allows carbon star production below these masses. A high fraction of the brightest among them should show S star characteristics indicative of atmospheric C/O~1, and many will form O-rich dust prior to their C-rich phase. These stars can be separated from their less-evolved counterparts by their characteristically red J-[8] colors.