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2211. Rotation curves of Seyfert galaxies with companions
ID:
ivo://CDS.VizieR/J/AJ/111/696
Title:
Rotation curves of Seyfert galaxies with companions
Short Name:
J/AJ/111/696
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents imaging and optical spectroscopy of paired Seyfert galaxies and their companions. The aim is to seek common properties of Seyfert galaxies in interacting systems, which might provide evidence of AGN triggering in a way independent of the usual two-sample statistics which have proven ambiguous on this issue. Three kinds of comparison have been made -- the kinds of interactions involving Seyfert galaxies, the relative luminosities of the Seyferts and their companions, and the level of kinematic disturbance as measured from rotation curves. (1) Dynamics and tidal features have been used to determine (or at least limit) the sense of orbital motion (direct/ retrograde/polar with respect to the Seyfert galaxy's disk) for many of these pairs. There is no obviously preferred kind of interaction -- direct, polar, and retrograde encounters are all well represented, despite the gross differences in dynamical response of a disk to these various kinds of encounter. To the extent that triggering of Seyfert nuclei occurs due to tidal encounters, the existence of a perturbation seems more important than its exact duration or detailed effects on the disk. However, the ratio of merging to paired Seyferts is higher than for disk galaxies in general, consistent with more effective triggering of AGN in this specific phase; the implied time scale for enhanced occurrence during mergers is the same as the timescape for merger remnants to appear as such, a few disk-edge crossing times (typically several times 10^8yr). (2) Seyfert nuclei occur preferentially in the brighter members of galaxy pairs, by a median of 0.93mag after making the maximal correction for contaminating nonstellar light in the nuclei. Only about 1/3 of this effect can be accounted for by the known tendency of Seyfert nuclei to occur in more luminous galaxies. Enhancement of AGN by interactions is evidently more effective for more luminous galaxies (though this will also be the case if both star formation and AGN occurrence are enhanced in the same galaxies). (3) The rotation curves of the paired Seyferts show systematically small regions of rising or solid-body rotation compared to the disk radius, as a group comparable to Sa but very different from Sb or Sc galaxies (even for Seyfert galaxies with Hubble type later than Sa). There is weak evidence that this difference is also present with respect to more isolated Seyfert galaxies. Despite the obvious utility of a dynamically disturbed disk for transport of angular momentum and "feeding the monster," Seyfert galaxies in pairs actually have smaller kinematic disturbances (measured by the maximum departure from a symmetric rotation curve, normalized to the full rotation amplitude) than found in a complete sample of non-Seyfert spirals in pairs.
2212. Rotation velocity & dynamical mass of gal. from HI sp.
ID:
ivo://CDS.VizieR/J/ApJ/898/102
Title:
Rotation velocity & dynamical mass of gal. from HI sp.
Short Name:
J/ApJ/898/102
Date:
21 Mar 2022 08:49:45
Publisher:
CDS
Description:
The integrated 21cm HI emission profile of a galaxy encodes valuable information on the kinematics, spatial distribution, and dynamical state of its cold interstellar medium. The line width, in particular, reflects the rotation velocity of the galaxy, which, in combination with a size scale, can be used to constrain the dynamical mass of the system. We introduce a new method based on the concept of the curve of growth to derive a set of robust parameters to characterize the line width, asymmetry, and concentration of the integrated HI spectra. We use mock spectra to evaluate the performance of our method, to estimate realistic systematic uncertainties for the proposed parameters, and to correct the line widths for the effects of instrumental resolution and turbulence broadening. Using a large sample of nearby galaxies with available spatially resolved kinematics, we demonstrate that the newly defined line widths can predict the rotational velocities of galaxies to within an accuracy of <~30km/s. We use the calibrated line widths, in conjunction with the empirical relation between the size and mass of HI disks, to formulate a prescription for estimating the dynamical mass within the HI-emitting region of gas-rich galaxies. Our formalism yields dynamical masses accurate to ~0.3dex based solely on quantities that can be derived efficiently and robustly from current and future extragalactic HI surveys. We further extend the dynamical mass calibration to the scale of the dark matter halo.
2213. Rot. velocities of APOGEE stars in Kepler field
ID:
ivo://CDS.VizieR/J/ApJ/898/76
Title:
Rot. velocities of APOGEE stars in Kepler field
Short Name:
J/ApJ/898/76
Date:
21 Mar 2022 08:47:46
Publisher:
CDS
Description:
We use 5337 spectroscopic vsini measurements of Kepler dwarfs and subgiants from the APOGEE survey to study stellar rotation trends. We find a detection threshold of 10km/s, which allows us to explore the spindown of intermediate-mass stars leaving the main sequence, merger products, young stars, and tidally synchronized binaries. We see a clear distinction between blue stragglers and the field turnoff in {alpha}-rich stars, with a sharp rapid rotation cutoff for blue stragglers consistent with the Kraft break. We also find rapid rotation and radial velocity variability in a sample of red straggler stars, considerably cooler than the giant branch, lending credence to the hypothesis that these are active, tidally synchronized binaries. We see clear evidence for a transition between rapid and slow rotation on the subgiant branch in the domain predicted by modern angular momentum evolution models. We find substantial agreement between the spectroscopic and photometric properties of KIC targets added by Huber+ (2014, J/ApJS/211/2) based on Two Micron All Sky Survey photometry. For the unevolved lower main sequence, we see the same concentration toward rapid rotation in photometric binaries as that observed in rotation period data, but at an enhanced rate. We attribute this difference to unresolved near-equal-luminosity spectroscopic binaries with velocity displacements on the order of the APOGEE resolution. Among cool unevolved stars we find an excess rapid rotator fraction of 4% caused by pipeline issues with photometric binaries.
2214. r-process abundances in AMBRE stars
ID:
ivo://CDS.VizieR/J/A+A/619/A143
Title:
r-process abundances in AMBRE stars
Short Name:
J/A+A/619/A143
Date:
21 Oct 2021
Publisher:
CDS
Description:
The chemical evolution of neutron capture elements in the Milky Way disc is still a matter of debate. There is a lack of statistically significant catalogues of such element abundances, especially those of the r-process. We aim to understand the chemical evolution of r-process elements in Milky Way disc. We focus on three pure r-process elements Eu, Gd, and Dy. We also consider a pure s-process element, Ba, in order to disentangle the different nucleosynthesis processes. We take advantage of high-resolution FEROS, HARPS, and UVES spectra from the ESO archive in order to perform a homogeneous analysis on 6500 FGK Milky Way stars. The chemical analysis is performed thanks to the automatic optimization pipeline GAUGUIN. We present abundances of Ba (5057 stars), Eu (6268 stars), Gd (5431 stars), and Dy (5479 stars). Based on the [{alpha}/Fe] ratio determined previously by the AMBRE Project, we chemically characterize the thin and the thick discs, and a metal-rich {alpha}-rich population. First, we find that the [Eu/Fe] ratio follows a continuous sequence from the thin disc to the thick disc as a function of the metallicity. Second, in thick disc stars, the [Eu/Ba] ratio is found to be constant, while the [Gd/Ba] and [Dy/Ba] ratios decrease as a function of the metallicity. These observations clearly indicate a different nucleosynthesis history in the thick disc between Eu and Gd-Dy. The [r/Fe] ratio in the thin disc is roughly around +0.1dex at solar metallicity, which is not the case for Ba. We also find that the {alpha}-rich metal-rich stars are also enriched in r-process elements (like thick disc stars), but their [Ba/Fe] is very different from thick disc stars. Finally, we find that the [r/{alpha}] ratio tends to decrease with metallicity, indicating that supernovae of different properties probably contribute differently to the synthesis of r-process elements and {alpha}-elements. We provide average abundance trends for [Ba/Fe] and [Eu/Fe] with rather small dispersions, and for the first time for [Gd/Fe] and [Dy/Fe]. This data may help to constrain chemical evolution models of Milky Way r- and s-process elements and the yields of massive stars. We emphasize that including yields of neutron-star or black hole mergers is now crucial if we want to quantitatively compare observations to Galactic chemical evolution models.
2215. R-Process Alliance: metal-poor star spectroscopy
ID:
ivo://CDS.VizieR/J/ApJS/249/30
Title:
R-Process Alliance: metal-poor star spectroscopy
Short Name:
J/ApJS/249/30
Date:
21 Oct 2021
Publisher:
CDS
Description:
This compilation is the fourth data release from the R-Process Alliance (RPA) search for r-process-enhanced stars and the second release based on "snapshot" high-resolution (R~30000) spectra collected with the du Pont 2.5m Telescope. In this data release, we propose a new delineation between the r-I and r-II stellar classes at [Eu/Fe]=+0.7, instead of the empirically chosen [Eu/Fe]=+1.0 level previously in use, based on statistical tests of the complete set of RPA data released to date. We also statistically justify the minimum level of [Eu/Fe] for definition of the r-I stars, [Eu/Fe]>+0.3. Redefining the separation between r-I and r-II stars will aid in the analysis of the possible progenitors of these two classes of stars and determine whether these signatures arise from separate astrophysical sources at all. Applying this redefinition to previous RPA data, the number of identified r-II and r-I stars changes to 51 and 121, respectively, from the initial set of data releases published thus far. In this data release, we identify 21 new r-II, 111 new r-I (plus 3 re-identified), and 7 new (plus 1 re-identified) limited-r stars out of a total of 232 target stars, resulting in a total sample of 72 new r-II stars, 232 new r-I stars, and 42 new limited-r stars identified by the RPA to date.
2216. R-Process Alliance: 1st release in Galactic halo
ID:
ivo://CDS.VizieR/J/ApJ/868/110
Title:
R-Process Alliance: 1st release in Galactic halo
Short Name:
J/ApJ/868/110
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents the detailed abundances and r-process classifications of 125 newly identified metal-poor stars as part of an ongoing collaboration, the R-Process Alliance. The stars were identified as metal-poor candidates from the RAdial Velocity Experiment (RAVE) and were followed up at high spectral resolution (R~31500) with the 3.5m telescope at Apache Point Observatory. The atmospheric parameters were determined spectroscopically from FeI lines, taking into account <3D> non-LTE corrections and using differential abundances with respect to a set of standards. Of the 125 new stars, 124 have [Fe/H]{<}-1.5, 105 have [Fe/H]{<}-2.0, and 4 have [Fe/H]{<}-3.0. Nine new carbon-enhanced metal-poor stars have been discovered, three of which are enhanced in r-process elements. Abundances of neutron-capture elements reveal 60 new r-I stars (with +0.3<=[Eu/Fe]<=+1.0 and [Ba/Eu]<0) and 4 new r-II stars (with [Eu/Fe]>+1.0). Nineteen stars are found to exhibit a "limited-r" signature ([Sr/Ba]>+0.5, [Ba/Eu]<0). For the r-II stars, the second- and third-peak main r-process patterns are consistent with the r-process signature in other metal-poor stars and the Sun. The abundances of the light, {alpha}, and Fe-peak elements match those of typical Milky Way (MW) halo stars, except for one r-I star that has high Na and low Mg, characteristic of globular cluster stars. Parallaxes and proper motions from the second Gaia data release yield UVW space velocities for these stars that are consistent with membership in the MW halo. Intriguingly, all r-II and the majority of r-I stars have retrograde orbits, which may indicate an accretion origin.
2217. RR Tel UV emission
ID:
ivo://CDS.VizieR/J/A+AS/124/425
Title:
RR Tel UV emission
Short Name:
J/A+AS/124/425
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
2218. RVel & Hipparcos positions of epsilon Eridani
ID:
ivo://CDS.VizieR/J/AJ/162/181
Title:
RVel & Hipparcos positions of epsilon Eridani
Short Name:
J/AJ/162/181
Date:
14 Mar 2022 06:39:08
Publisher:
CDS
Description:
{epsilon}Eridani is a young planetary system hosting a complex multibelt debris disk and a confirmed Jupiter-like planet orbiting at 3.48au from its host star. Its age and architecture are thus reminiscent of the early Solar System. The most recent study of Mawet et al., which combined radial-velocity data and Ms-band direct imaging upper limits, started to constrain the planet's orbital parameters and mass, but are still affected by large error bars and degeneracies. Here we make use of the most recent data compilation from three different techniques to further refine {epsilon}Eridani b's properties: RVs, absolute astrometry measurements from the Hipparcos and Gaia missions, and new Keck/NIRC2 Ms-band vortex coronagraph images. We combine this data in a Bayesian framework. We find a new mass, M_b_=0.66_-0.09_^+0.12^M_Jup_, and inclination, i=78.81_-22.41_^+29.34^deg, with at least a factor 2 of improvement over previous uncertainties. We also report updated constraints on the longitude of the ascending node, the argument of the periastron, and the time of periastron passage. With these updated parameters, we can better predict the position of the planet at any past and future epoch, which can greatly help define the strategy and planning of future observations and with subsequent data analysis. In particular, these results can assist the search for a direct detection with JWST and the Nancy Grace Roman Space Telescope's coronagraph instrument.
2219. RV photon limits of well-characterized F-M stars
ID:
ivo://CDS.VizieR/J/ApJS/247/11
Title:
RV photon limits of well-characterized F-M stars
Short Name:
J/ApJS/247/11
Date:
21 Oct 2021
Publisher:
CDS
Description:
The determination of extrasolar planet masses with the radial velocity (RV) technique requires spectroscopic Doppler information from the planet's host star, which varies with stellar brightness and temperature. We analyze the Doppler information in spectra from dwarfs of spectral types F-M utilizing empirical information from HARPS and CARMENES data and model spectra. We revisit the question of whether optical or near-infrared instruments are more efficient for RV observations in low-mass stars, and we come to the conclusion that an optical setup (BVR bands) is more efficient than a near-infrared one (YJHK) in dwarf stars hotter than 3200K. We publish a catalog of 46480 well-studied F-M dwarfs in the solar neighborhood, and we compare its distribution to more than 1 million stars from Gaia DR2. For all stars, we estimate the RV photon noise achievable in typical observations under the assumption of no activity jitter and slow rotation. We find that with an ESPRESSO-like instrument at an 8m telescope, a photon noise limit of 10cm/s or lower can be reached in more than 280 stars in a 5 minute observation. At 4m telescopes, a photon noise limit of 1m/s can be reached in a 10 minute exposure in approximately 10000 predominantly Sun-like stars with a HARPS-like (optical) instrument. The same applies to ~3000 stars for a red optical setup that covers the R and I bands and ~700 stars for a near-infrared instrument. For the latter two, many of the targets are nearby M dwarfs. Finally, we identify targets in which Earth-mass planets within the liquid water habitable zone can cause RV amplitudes comparable to the RV photon noise. Assuming the same exposure times as above, we find that an ESPRESSO-like instrument can reach this limit for 1M_{Earth}_ planets in more than 1000 stars. The optical, red optical, and near-infrared configurations reach the limit for 2M_{Earth}_ planets in approximately 500, 700, and 200 stars, respectively. An online tool is provided to estimate the RV photon noise as a function of stellar temperature and brightness and wavelength coverage.
2220. RVs and opt. photometry of the host star TOI-677
ID:
ivo://CDS.VizieR/J/AJ/159/145
Title:
RVs and opt. photometry of the host star TOI-677
Short Name:
J/AJ/159/145
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of TOI-677b, first identified as a candidate in light curves obtained within Sectors 9 and 10 of the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed with radial velocities. TOI-677b has a mass of M_p_=1.236_-0.067_^+0.069^M_J_, a radius of R_P_=1.170{+/-}0.03R_J_, and orbits its bright host star (V=9.8mag) with an orbital period of 11.23660{+/-}0.00011d, on an eccentric orbit with e=0.435{+/-}0.024. The host star has a mass of M_*_=1.181{+/-}0.058M_{sun}_, a radius of R_*_=1.28_-0.03_^+0.03^R_{sun}_, an age of 2.92_-0.73_^+0.80^Gyr and solar metallicity, properties consistent with a main-sequence late-F star with T_eff_=6295{+/-}77K. We find evidence in the radial velocity measurements of a secondary long-term signal, which could be due to an outer companion. The TOI-677b system is a well-suited target for Rossiter-Mclaughlin observations that can constrain migration mechanisms of close-in giant planets.

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