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2921. Radial velocities of NGC 6822 carbon stars
ID:
ivo://CDS.VizieR/J/MNRAS/462/3376
Title:
Radial velocities of NGC 6822 carbon stars
Short Name:
J/MNRAS/462/3376
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using spectra taken with the AAOmega spectrograph, we measure the radial velocities of over 100 stars, many of which are intermediate age carbon stars, in the direction of the dwarf irregular galaxy NGC 6822. Kinematic analysis suggests that the carbon stars in the sample are associated with NGC 6822, and estimates of its radial velocity and galactic rotation are made from a star-by-star analysis of its carbon star population. We calculate a heliocentric radial velocity for NGC 6822 of -51+/-3km/s and show that the population rotates with a mean rotation speed of 11.2+/-2.1km/s at a mean distance of 1.1kpc from the galactic centre, about a rotation axis with a position angle of 26{deg}+/-13{deg}, as projected on the sky. This is close to the rotation axis of the HI gas disc and suggests that NGC 6822 is not a polar ring galaxy, but is dynamically closer to a late-type galaxy. However, the rotation axis is not aligned with the minor axis of the AGB isodensity profiles and this remains a mystery.
2922. Radial velocities of NGC1316 globular clusters
ID:
ivo://CDS.VizieR/J/A+A/569/A41
Title:
Radial velocities of NGC1316 globular clusters
Short Name:
J/A+A/569/A41
Date:
21 Oct 2021
Publisher:
CDS
Description:
The merger remnant NGC 1316 (Fornax A) is one of the most important objects regarding the investigation of and thus an important object to study merger-related processes. A recent photometric study used globular clusters in NGC 1316 to constrain its star formation history, but without the knowledge of individual radial velocities. The kinematical properties of the globular cluster system in comparison with the diffuse stellar light might give more insight into the formation of NGC 1316. Of particular interest is the dark matter content. Planetary nebulae in NGC 1316 indicate a massive dark halo, and globular cluster velocities provide independent evidence. We aim at measuring radial velocities of globular clusters in NGC 1316. We use these kinematical data to investigate the global structure of NGC 1316 and to constrain the dark matter content. We perform multiobject spectroscopy with VLT/FORS2 and MXU. Out of 562 slits, we extract radial velocities for 177 globular clusters. Moreover, we measure radial velocities of the integrated galaxy light, using slits with a sufficiently bright sky. To these data, we add 20 cluster velocities from the literature. In an appendix, we identify new morphological features of NGC 1316 and its companion galaxy NGC 1317.
2923. Radial velocities of stars in Bootes I
ID:
ivo://CDS.VizieR/J/ApJ/736/146
Title:
Radial velocities of stars in Bootes I
Short Name:
J/ApJ/736/146
Date:
21 Oct 2021
Publisher:
CDS
Description:
We develop, implement, and characterize an enhanced data reduction approach which delivers precise, accurate, radial velocities from moderate resolution spectroscopy with the fiber-fed VLT/FLAMES+GIRAFFE facility. This facility, with appropriate care, delivers radial velocities adequate to resolve the intrinsic velocity dispersions of the very faint dwarf spheroidal (dSph) galaxies. Importantly, repeated measurements let us reliably calibrate our individual velocity errors (0.2km/s<={delta}_V_<=5km/s) and directly detect stars with variable radial velocities. We show, by application to the Bootes I dSph, that the intrinsic velocity dispersion of this system is significantly below 6.5km/s reported by previous studies. Our data favor a two-population model of Bootes I, consisting of a majority "cold" stellar component, with velocity dispersion 2.4^+0.9^_-0.5_km/s, and a minority "hot" stellar component, with velocity dispersion ~9km/s, although we cannot completely rule out a single component distribution with velocity dispersion 4.6^0.8^_-0.6_km/s. We speculate that this complex velocity distribution actually reflects the distribution of velocity anisotropy in Bootes I, which is a measure of its formation processes.
2924. Radial velocities of stars near Leo I
ID:
ivo://CDS.VizieR/J/ApJ/675/201
Title:
Radial velocities of stars near Leo I
Short Name:
J/ApJ/675/201
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new kinematic results for 387 stars near the Milky Way satellite dwarf spheroidal galaxy Leo I. Spectra were obtained with the Hectochelle multiobject echelle spectrograph on the MMT, centered in the optical near 5200{AA}.
2925. Radial Velocities of the local universe
ID:
ivo://CDS.VizieR/J/A+AS/102/57
Title:
Radial Velocities of the local universe
Short Name:
J/A+AS/102/57
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper is the second one in a series dedicated to the study of the kinematics of the local universe. It gives 361 new optical and radio redshifts measured at ESO, OHP and Nancay Observatories.
2926. Radial velocities of UCOs in Fornax
ID:
ivo://CDS.VizieR/J/A+A/383/823
Title:
Radial velocities of UCOs in Fornax
Short Name:
J/A+A/383/823
Date:
21 Oct 2021
Publisher:
CDS
Description:
The relation between the Ultra Compact Objects (hereafter UCOs) recently discovered in the Fornax cluster (Drinkwater et al., 2000PASA...17..227D; Hilker et al., 1999, Cat. <J/A+AS/134/75>) and the brightest globular clusters associated with the central galaxy NGC 1399 has been investigated. A spectroscopic survey on compact objects in the central region of the Fornax cluster was carried out with the 2.5 m du Pont telescope (LCO) at Las Campanas, in the three nights of 2000/12/30 to 2001/01/01. The magnitude limit was approx. V=21 mag, the spectral resolution approx. 4{AA}. UCOs and the bright NGC 1399 globular clusters with similar brightness were inspected. 12 GCs from the bright end of the globular cluster luminosity function have been identified as Fornax members. Eight are new members, four were known as members from before.
2927. Radial velocity in Draco
ID:
ivo://CDS.VizieR/J/MNRAS/330/792
Title:
Radial velocity in Draco
Short Name:
J/MNRAS/330/792
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present stellar radial velocity data for the Draco dwarf spheroidal (dSph) galaxy obtained using the AF2/WYFFOS instrument combination on the William Herschel Telescope. Our data set consists of 186 member stars, 159 of which have good quality velocities, extending to a magnitude V~19.5 with a mean velocity precision of ~2km/s. As this survey is based on a high-precision photometric target list, it contains many more Draco members at large radii. For the first time, this allows a robust determination of the radial behaviour of the velocity dispersion in a dSph.
2928. Radiation fields in star-forming galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/436/1302
Title:
Radiation fields in star-forming galaxies
Short Name:
J/MNRAS/436/1302
Date:
21 Oct 2021
Publisher:
CDS
Description:
We provide a library of diffuse stellar radiation fields in spiral galaxies derived using calculations of the transfer of stellar radiation from the main morphological components - discs, thin discs and bulges - through the dusty interstellar medium. These radiation fields are self-consistent with the solutions for the integrated panchromatic spectral energy distributions (SEDs) previously presented using the same model. Because of this, observables calculated from the radiation fields, such as gamma-ray or radio emission, can be self-consistently combined with the solutions for the ultraviolet/optical/submillimeter SEDs, thus expanding the range of applicability of the radiation transfer model to a broader range of wavelengths and physical quantities.
2929. Radiation fields of the Milky Way
ID:
ivo://CDS.VizieR/J/MNRAS/470/2539
Title:
Radiation fields of the Milky Way
Short Name:
J/MNRAS/470/2539
Date:
21 Oct 2021
Publisher:
CDS
Description:
We provide a library for the ultraviolet - submillimetre (submm) interstellar radiation fields (ISRFs) of the Milky Way (MW), derived from modelling COBE, IRAS and Planck maps of the all-sky emission in the near-, mid-, far-infrared and submm. The library was produced using the axisymmetric radiative transfer model that we have previously implemented to model the panchromatic spectral energy distributions (SEDs) of star-forming galaxies in the nearby universe, but with a new methodology allowing for optimization of the radial and vertical geometry of stellar emissivity and dust opacity, as deduced from the highly resolved emission seen from the vantage point of the Sun.
2930. Radiative contribution from stripped stars
ID:
ivo://CDS.VizieR/J/A+A/629/A134
Title:
Radiative contribution from stripped stars
Short Name:
J/A+A/629/A134
Date:
21 Oct 2021
Publisher:
CDS
Description:
Stars stripped of their envelopes from interaction with a binary companion emit a significant fraction of their radiation as ionizing photons. They are potentially important stellar sources of ionizing radiation, however, they are still often neglected in spectral synthesis simulations or simulations of stellar feedback. In anticipating the large datasets of galaxy spectra from the upcoming James Webb Space Telescope, we modeled the radiative contribution from stripped stars by using detailed evolutionary and spectral models. We estimated their impact on the integrated spectra and specifically on the emission rates of HI-, HeI-, and HeII-ionizing photons from stellar populations. We find that stripped stars have the largest impact on the ionizing spectrum of a population in which star formation halted several Myr ago. In such stellar populations, stripped stars dominate the emission of ionizing photons, mimicking a younger stellar population in which massive stars are still present. Our models also suggest that stripped stars have harder ionizing spectra than massive stars. The additional ionizing radiation, with which stripped stars contribute affects observable properties that are related to the emission of ionizing photons from stellar populations. In co-eval stellar populations, the ionizing radiation from stripped stars increases the ionization parameter and the production efficiency of hydrogen ionizing photons. They also cause high values for these parameters for about ten times longer than what is predicted for massive stars. The effect on properties related to non-ionizing wavelengths is less pronounced, such as on the ultraviolet continuum slope or stellar contribution to emission lines. However, the hard ionizing radiation from stripped stars likely introduces a characteristic ionization structure of the nebula, which leads to the emission of highly ionized elements such as O^2+^ and C^3+^. We, therefore, expect that the presence of stripped stars affects the location in the BPT diagram and the diagnostic ratio of OIII to OII nebular emission lines. Our models are publicly available through CDS database and on the STARBURST99 website.