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631. Dynamics in E+E pairs of galaxies
ID:
ivo://CDS.VizieR/J/A+A/297/28
Title:
Dynamics in E+E pairs of galaxies
Short Name:
J/A+A/297/28
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a kinematic study of three E+E galaxy pairs, NGC 741/742, 1587/1588 (CPG 99) and 2672/2673 (CPG 175). All three pairs show a similar morphological distortion (i.e. the off-centering of inner versus outer isophotes; Davoust & Prugniel 1988) which is ascribed to the ongoing interaction. The data was obtained at the CFHT equipped with the Herzberg Spectrograph at a resolution of 0.88 Apx^-1^. NGC 741 and 2673 show significant rotation along the apparent minor axis. Both components of CPG 99 rotate very fast (with no evidence for rotation along the minor axis of either component). None of the galaxies show abnormally high central velocity dispersion. We report some of the first clear detections of well defined velocity dispersion curves for interacting pairs. They show a systematic decrease with distance from the center, as expected for normal ellipticals. They do not show obvious heating in the outer parts as was previously reported. NGC 741 and 2672 show, respectively, possible U and inverse U-shaped structure in their velocity profiles.
632. Dynamics of A3266. I. An Optical View.
ID:
ivo://CDS.VizieR/J/MNRAS/468/2645
Title:
Dynamics of A3266. I. An Optical View.
Short Name:
J/MNRAS/468/2645
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present spectroscopy of 880 galaxies within a 2-degree field around the massive, merging cluster Abell 3266. This sample, which includes 704 new measurements, was combined with the existing redshifts measurements to generate a sample of over 1300 spectroscopic redshifts; the largest spectroscopic sample in the vicinity of A3266 to date. We define a cluster sub-sample of 790 redshifts which lie within a velocity range of 14000 to 22000km/s and within 1 degree of the cluster centre. A detailed structural analysis finds A3266 to have a complex dynamical structure containing six groups and filaments to the north of the cluster as well as a cluster core which can be decomposed into two components split along a northeast-southwest axis, consistent with previous X-ray observations. The mean redshift of the cluster core is found to be 0.0594+/-0.0005 and the core velocity dispersion is given as 1462+/-99km/s. The overall velocity dispersion and redshift of the entire cluster and related structures are 1337+/-67 km/s and 0.0596+/-0.0002, respectively, though the high velocity dispersion does not represent virialised motions but rather is due to relative motions of the cluster components. We posit A3266 is seen following a merger along the northeast southwest axis, however, the rich substructure in the rest of the cluster suggests that the dynamical history is more complex than just a simple merger with a range of continuous dynamical interactions taking place. It is thus likely that turbulence in A3266 is very high, even for a merging cluster.
633. Early light curve of SN 2013gy
ID:
ivo://CDS.VizieR/J/A+A/627/A174
Title:
Early light curve of SN 2013gy
Short Name:
J/A+A/627/A174
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an early-phase g-band light curve and visual-wavelength spectra of the normal Type Ia supernova (SN) 2013gy. The light curve is constructed by determining the appropriate S-corrections to transform KAIT natural-system B- and V-band photometry and Carnegie Supernova Project natural-system g-band photometry to the Pan-STARRS1 g-band natural photometric system. A Markov chain Monte Carlo calculation provides a best-fit single power-law function to the first ten epochs of photometry described by an exponent of 2.16^+0.06^_0.06_ and a time of first light of MJD 56629.4^+0.1^_0.1_, which is 1.93^+0.12^_0.13_ days (i.e., <48hr) before the discovery date (2013 December 4.84 UT) and -19.10^+0.12^_0.13_ days before the time of B-band maximum (MJD 56648.50.1). The estimate of the time of first light is consistent with the explosion time inferred from the evolution of the SiII 6355 Doppler velocity. Furthermore, discovery photometry and previous nondetection limits enable us to constrain the companion radius down to Rc<=4R_{sun}_. In addition to our early-time constraints, we used a deep +235 day nebular-phase spectrum from Magellan/IMACS to place a stripped H-mass limit of <0.018M_{sun}_. Combined, these limits effectively rule out H-rich nondegenerate companions.
634. Early spectral evolution of Nova Sgr 2004
ID:
ivo://CDS.VizieR/J/A+A/459/875
Title:
Early spectral evolution of Nova Sgr 2004
Short Name:
J/A+A/459/875
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present optical and near-infrared spectral evolution of the Galactic nova V5114 Sgr (2004) during few months after the outburst. We use multi-band photometry and line intensities derived from spectroscopy to put constrains on the distance and the physical conditions of the ejecta of V5114 Sgr.
635. Early-Tyoe Galaxies in SDSS and GALEX
ID:
ivo://CDS.VizieR/J/MNRAS/444/2571
Title:
Early-Tyoe Galaxies in SDSS and GALEX
Short Name:
J/MNRAS/444/2571
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use the Hernandez-Perez and Bruzual stellar population synthesis models to study the role of interacting binary pairs as progenitors of extreme horizontal branch (EHB) stars. We assemble a sample of 3417 early-type galaxies observed both in the optical (SDSS-DR8) and the UV (GALEX-GR6). The galaxies in our sample can be classified according to their position in the colour-colour diagram as UV-weak or red-sequence galaxies (~48%), UV-strong or UVX galaxies (~9%), and recent star-forming galaxies (~43%). Analysing this sample using the models for various choices of basic model parameters, we conclude that (a) the UVr colours of UV-weak and UV-strong galaxies are reproduced by the models as long as the fraction of binary stars is at least 15%. (b) Higher metallicity models (Z=0.02 and 0.03) reproduce the colours of UV-weak and UV-strong galaxies better than lower Z models. The Z=0.03 model is slightly bluer than the Z=0.02 model in the UV-strong region, indicating a weak relationship between UVX and Z. (c) The strength of UVX increases with age in the model population. This is at variance with the results of other models that include binary stars as progenitors of EHB stars.
636. 127 early type and pre-main-sequence stars in W4
ID:
ivo://CDS.VizieR/J/ApJ/899/121
Title:
127 early type and pre-main-sequence stars in W4
Short Name:
J/ApJ/899/121
Date:
15 Mar 2022 03:47:36
Publisher:
CDS
Description:
Stellar kinematics provides the key to understanding the formation process and dynamical evolution of stellar systems. Here, we present a kinematic study of the massive star-forming region (SFR) W4 in the Cassiopeia OB6 association using the Gaia Data Release 2 and high-resolution optical spectra. This SFR is composed of a core cluster (IC1805) and a stellar population distributed over 20pc, which is a typical structural feature found in many OB associations. According to a classical model, this structural feature can be understood in the context of the dynamical evolution of a star cluster. The core-extended structure exhibits internally different kinematic properties. Stars in the core have an almost isotropic motion, and they appear to reach virial equilibrium given their velocity dispersion (0.9{+/-}0.3km/s) comparable to that in a virial state (~0.8km/s). On the other hand, the distributed population shows a clear pattern of radial expansion. From the N-body simulation for the dynamical evolution of a model cluster in subvirial state, we reproduce the observed structure and kinematics of stars. This model cluster experiences collapse for the first 2Myr. Some members begin to radially escape from the cluster after the initial collapse, eventually forming a distributed population. The internal structure and kinematics of the model cluster appear similar to those of W4. Our results support the idea that the stellar population distributed over 20pc in W4 originate from the dynamical evolution of IC1805.
637. Early-type BCGs with star formation
ID:
ivo://CDS.VizieR/J/MNRAS/423/422
Title:
Early-type BCGs with star formation
Short Name:
J/MNRAS/423/422
Date:
21 Oct 2021
Publisher:
CDS
Description:
We identify a total of 120 early-type brightest cluster galaxies (BCGs) at 0.1<z<0.4 in two recent large cluster catalogues selected from the Sloan Digital Sky Survey (SDSS). They are selected with strong emission lines in their optical spectra, with both H{alpha} and [OII]{lambda}3727 line emission, which indicates significant ongoing star formation. They constitute about ~0.5 per cent of the largest, optically selected, low-redshift BCG sample, and the fraction is a strong function of cluster richness. Their star formation history can be well described by a recent minor and short starburst superimposed on an old stellar component, with the recent episode of star formation contributing on average only less than 1 per cent of the total stellar mass. We show that the more massive star-forming BCGs in richer clusters tend to have higher star formation rate (SFR) and specific SFR (SFR per unit galaxy stellar mass). We also compare their statistical properties with a control sample selected from X-ray luminous clusters, and show that the fraction of star-forming BCGs in X-ray luminous clusters is almost one order of magnitude larger than that in optically selected clusters. BCGs with star formation in cooling flow clusters usually have very flat optical spectra and show the most active star formation, which may be connected with cooling flows.
638. EBHIS spectra and HI column density maps
ID:
ivo://CDS.VizieR/J/A+A/585/A41
Title:
EBHIS spectra and HI column density maps
Short Name:
J/A+A/585/A41
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Effelsberg-Bonn HI Survey (EBHIS) is a new 21-cm survey performed with the 100-m telescope at Effelsberg. It covers the whole northern sky out to a redshift of z~0.07 and comprises HI line emission from the Milky Way and the Local Volume. We aim to substitute the northern-hemisphere part of the Leiden/Argentine/Bonn Milky Way HI survey (LAB) with this first EBHIS data release, which presents the HI gas in the Milky Way regime. The use of a seven-beam L-band array made it feasible to perform this all-sky survey with a 100-m class telescope in a reasonable amount of observing time. State-of-the-art fast-Fourier-transform spectrometers provide the necessary data read-out speed, dynamic range, and spectral resolution to apply software radio-frequency interference mitigation. EBHIS is corrected for stray radiation and employs frequency-dependent flux-density calibration and sophisticated baseline-removal techniques to ensure the highest possible data quality. Detailed analyses of the resulting data products show that EBHIS is not only outperforming LAB in terms of sensitivity and angular resolution, but also matches the intensity-scale of LAB extremely well, allowing EBHIS to be used as a drop-in replacement for LAB. Data products are made available to the public in a variety of forms. Most important, we provide a properly gridded Milky Way HI column density map in HEALPix representation. To maximize the usefulness of EBHIS data, we estimate uncertainties in the HI column density and brightness temperature distributions, accounting for systematic effects.
639. EBLM J2349-32 photometry, RV and spectra
ID:
ivo://CDS.VizieR/J/A+A/626/A119
Title:
EBLM J2349-32 photometry, RV and spectra
Short Name:
J/A+A/626/A119
Date:
21 Oct 2021
Publisher:
CDS
Description:
Some M-dwarfs around F-/G-type stars have been measured to be hotter and larger than predicted by stellar evolution models. Inconsistencies between observations and models need to be addressed with more mass, radius, and luminosity measurements of low-mass stars to test and refine evolutionary models. Our aim is to measure the masses, radii and ages of the stars in five low-mass eclipsing binary systems discovered by the WASP survey. We used WASP photometry to establish eclipse-time ephemerides and to obtain initial estimates for the transit depth and width. Radial velocity measurements were simultaneously fitted with follow-up photometry to find the best-fitting orbital solution. This solution was combined with measurements of atmospheric parameters to interpolate evolutionary models and estimate the mass of the primary star, and the mass and radius of the M-dwarf companion. We assess how the best fitting orbital solution changes if an alternative limb-darkening law is used and quantify the systematic effects of unresolved companions. We also gauge how the best-fitting evolutionary model changes if different values are used for the mixing length parameter and helium enhancement. We report the mass and radius of five M-dwarfs and find little evidence of inflation with respect to evolutionary models. The primary stars in two systems are near the "blue hook" stage of their post sequence evolution, resulting in two possible solutions for mass and age. We find that choices in helium enhancement and mixing-length parameter can introduce an additional 3-5% uncertainty in measured M-dwarf mass. Unresolved companions can introduce an additional 3-8% uncertainty in the radius of an M-dwarf, while the choice of limb-darkening law can introduce up to an additional 2% uncertainty. The choices in orbital fitting and evolutionary models can introduce significant uncertainties in measurements of physical properties of such systems.
640. Echelle spectra of 10 bright asteroids
ID:
ivo://CDS.VizieR/J/A+A/462/795
Title:
Echelle spectra of 10 bright asteroids
Short Name:
J/A+A/462/795
Date:
21 Oct 2021
Publisher:
CDS
Description:
Echelle spectra of 10 bright asteroids are presented and compared against an observed twilight spectrum and a computed Solar spectrum. Spectra covering a 2130{AA} spectral range centered on 5785{AA} are of high resolving power and high signal to noise ratio. We compare detailed properties of spectral lines and not albedo variations. It is shown that the normalized Solar and asteroid spectra are identical except for radial velocity (RV) shifts which can be predicted at accuracy level of 1m/s. So asteroids are proposed as new and extremely accurate radial velocity standards. Predicted and measured RVs of observed asteroids match within the limits of accuracy of the instrument. There are numerous absorption lines in the reflected Solar spectrum. This allows a direct mapping of the resolving power of a spectrograph between and along echelle spectral orders. Thus asteroid spectra can be used to test the wavelength calibration and resolving power of spectrographs on the ground as well as in space, including the Gaia mission of ESA.

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