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1131. Fundamental planes of early-type galaxies
ID:
ivo://CDS.VizieR/J/ApJ/689/913
Title:
Fundamental planes of early-type galaxies
Short Name:
J/ApJ/689/913
Date:
21 Oct 2021
Publisher:
CDS
Description:
We derive the fundamental plane (FP) relation for a sample of 1430 early-type galaxies (ETGs) in the optical (r band) and the near-infrared (K band), by combining SDSS-DR5 and UKIDSS (UKIRT Infrared Deep Sky Survey, 2007MNRAS.379.1599L), second release data. With such a large, homogeneous data set, we are able to assess the dependence of the FP on the wave band. Our analysis indicates that the FP of luminous early-type galaxies is essentially wave band-independent, with its coefficients increasing at most by 8% from the optical to the NIR. This finding fits well into a consistent picture in which the tilt of the FP is not driven by stellar populations but results from other effects, such as nonhomology. In this framework, the optical and NIR FPs require more massive galaxies to be slightly more metal-rich than less massive ones, and to have highly synchronized ages, with an age variation per decade in mass smaller than a few percent.
1132. Fundamental stellar & halo data for local galaxies
ID:
ivo://CDS.VizieR/J/ApJ/859/2
Title:
Fundamental stellar & halo data for local galaxies
Short Name:
J/ApJ/859/2
Date:
21 Oct 2021
Publisher:
CDS
Description:
We build templates of rotation curves as a function of the I-band luminosity via the mass modeling (by the sum of a thin exponential disk and a cored halo profile) of suitably normalized, stacked data from wide samples of local spiral galaxies. We then exploit such templates to determine fundamental stellar and halo properties for a sample of about 550 local disk-dominated galaxies with high-quality measurements of the optical radius R_opt_ and of the corresponding rotation velocity V_opt_. Specifically, we determine the stellar M_*_ and halo M_H_ masses, the halo size R_H_ and velocity scale V_H_, and the specific angular momenta of the stellar j_*_ and dark matter j_H_ components. We derive global scaling relationships involving such stellar and halo properties both for the individual galaxies in our sample and for their mean within bins; the latter are found to be in pleasing agreement with previous determinations by independent methods (e.g., abundance matching techniques, weak-lensing observations, and individual rotation curve modeling). Remarkably, the size of our sample and the robustness of our statistical approach allow us to attain an unprecedented level of precision over an extended range of mass and velocity scales, with 1{sigma} dispersion around the mean relationships of less than 0.1dex. We thus set new standard local relationships that must be reproduced by detailed physical models, which offer a basis for improving the subgrid recipes in numerical simulations, that provide a benchmark to gauge independent observations and check for systematics, and that constitute a basic step toward the future exploitation of the spiral galaxy population as a cosmological probe.
1133. FUV and NUV magnitudes of ETG
ID:
ivo://CDS.VizieR/J/MNRAS/446/2030
Title:
FUV and NUV magnitudes of ETG
Short Name:
J/MNRAS/446/2030
Date:
21 Oct 2021
Publisher:
CDS
Description:
We extend our initial study of the connection between the UV colour of galaxies and both the inferred stellar mass-to-light ratio, {Upsilon}*, and a mass-to-light ratio referenced to Salpeter initial mass function (IMF) models of the same age and metallicity, {Upsilon}*/{Upsilon}_Sal_, using new UV magnitude measurements for a much larger sample of early-type galaxies, ETGs, with dynamically determined mass-to-light ratios. We confirm the principal empirical finding of our first study, a strong correlation between the GALEX FUV-NUV colour and {Upsilon}*. We show that this finding is not the result of spectral distortions limited to a single passband (e.g. metallicity-dependent line-blanketing in the NUV band), or of the analysis methodology used to measure {Upsilon}*, or of the inclusion or exclusion of the correction for stellar population effects as accounted for using {Upsilon}*/{Upsilon}_Sal_. The sense of the correlation is that galaxies with larger {Upsilon}*, or larger {Upsilon}*/{Upsilon}_Sal_, are bluer in the UV. We conjecture that differences in the low-mass end of the stellar IMF are related to the nature of the extreme horizontal branch stars generally responsible for the UV flux in ETGs. If so, then UV colour can be used to identify ETGs with particular IMF properties and to estimate {Upsilon}*. We also demonstrate that UV colour can be used to decrease the scatter about the Fundamental Plane and Manifold, and to select peculiar galaxies for follow-up with which to further explore the cause of variations in {Upsilon}* and UV colour.
1134. FUV excess in early-type galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/414/3410
Title:
FUV excess in early-type galaxies
Short Name:
J/MNRAS/414/3410
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present surface photometry of a sample of 52 galaxies from the GALaxy Evolution eXplorer (GALEX) and Two-Micron All-Sky Survey (2MASS) data archives. These include 32 normal elliptical galaxies, 10 ellipticals with weak LINER or other nuclear activity and 10 star-forming ellipticals or early-type spirals. We examine the spatial distribution of the far-ultraviolet excess in these galaxies, and its correlation with dynamical and stellar population properties of the galaxies.
1135. FUV/HI relations in nearby galaxies
ID:
ivo://CDS.VizieR/J/AJ/140/1194
Title:
FUV/HI relations in nearby galaxies
Short Name:
J/AJ/140/1194
Date:
21 Oct 2021
Publisher:
CDS
Description:
We combine data from The HI Nearby Galaxy Survey and the GALEX Nearby Galaxy Survey to study the relationship between atomic hydrogen (HI) and far-ultraviolet (FUV) emission outside the optical radius (r25) in 17 spiral and 5 dwarf galaxies. In this regime, HI is likely to represent most of the interstellar medium (ISM) and FUV emission to trace recent star formation with little bias due to extinction, so that the two quantities closely trace the underlying relationship between gas and star formation rate (SFR).
1136. F175W and F275W photometry of M31 and M32
ID:
ivo://CDS.VizieR/J/ApJ/504/113
Title:
F175W and F275W photometry of M31 and M32
Short Name:
J/ApJ/504/113
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Faint Object Camera (FOC) ultraviolet images of the central 14"x14" of Messier 31 and Messier 32. The hot stellar populations detected in the composite UV spectra of these nearby galaxies are partially resolved into individual stars, and their individual colors and apparent magnitudes are measured. We detect 433 stars in M31 and 138 stars in M32, down to detection limits m_F275W_=25.5mag and m_F175W_=24.5mag.
1137. Gaia Alerts with LAMOST and SDSS
ID:
ivo://CDS.VizieR/J/other/ApSS/365.89
Title:
Gaia Alerts with LAMOST and SDSS
Short Name:
J/other/ApSS/365
Date:
21 Oct 2021
Publisher:
CDS
Description:
The ESA-Gaia satellite is regularly producing Alerts on objects where photometric variability has been detected after several passages over the same region of the sky. The physical nature of these objects has often to be determined with the help of complementary observations from ground-based facilities. We have compared the list of Gaia Alerts (from the beginning in 2014 to Nov. 1st, 2018) with archival LAMOST and SDSS spectroscopic data. A search radius of 3" has been adopted. In using survey data, the date of the ground-based observation rarely corresponds to the date of the Alert, but this allows at least the identification of the source if it is persistent, or the host galaxy if the object was only transient like a supernova (SN). Some of the objects have several LAMOST observations, and we complemented this search by adding also SDSS DR15 data in order to look for long-term variability. A list of Gaia Nuclear Transients (GNT) from Kostrzewa-Rutkowska et al. (2018. 2018MNRAS.481..307K, Cat. J/MNRAS/481/307), has been included in this search also. We found 26 Gaia Alerts with spectra in LAMOST+SDSS labelled as stars, among which 12 have multi-epoch spectra. A majority of them are Cataclysmic Variables (CVs). Similarly, 206 Gaia Alerts have associated spectra labelled as galaxies, among which 49 have multi-epoch spectra. Those spectra were generally obtained on a date widely different from the Alert date, and are mostly emission-line galaxies with no particularity (except a few Seyferts), leading to the suspicion that most of the Alerts were due to a SN. As for the GNT list, we found 55 associated spectra labelled as galaxies, among them 13 with multi-epoch spectra. In these two galaxy samples, in only two cases, Gaia17aal and GNTJ170213+2543, was the date of the spectroscopic observation close enough to the Alert date: we find a trace of the SN itself in their LAMOST spectrum, both being now classified here as a type Ia SN. Compared to the galaxy sample from the Gaia alerts, the GNT sample has a higher proportion of AGNs, suggesting that some of the detected variations are also due to the AGN itself. Similarly for Quasars, we found only 30 Gaia Alerts but 68 GNT cases associated with single epoch quasar spectra in the databases. In addition to those, 12 plus 23 are quasars where multi-epoch spectra are available. For ten out of these 35, their multi-epoch spectra show appearance or disappearance of the broad Balmer lines and also variations in the continuum, qualifying them as "Changing Look Quasars" and therefore significantly increasing the available sample of such objects.
1138. Gaia DR2 PMs of stars in ultra-faint MW satellites
ID:
ivo://CDS.VizieR/J/ApJ/863/89
Title:
Gaia DR2 PMs of stars in ultra-faint MW satellites
Short Name:
J/ApJ/863/89
Date:
21 Oct 2021
Publisher:
CDS
Description:
The second data release from the Gaia mission (DR2) provides a comprehensive and unprecedented picture of the motions of astronomical sources in the plane of the sky, extending from the solar neighborhood to the outer reaches of the Milky Way. I present proper-motion measurements based on Gaia DR2 for 17 ultra-faint dwarf galaxies within 100kpc of the Milky Way. I compile the spectroscopically confirmed member stars in each dwarf bright enough for Gaia astrometry from the literature, producing member samples ranging from two stars in Triangulum II to 68 stars in Bootes I. From the spectroscopic member catalogs, I estimate the proper motion of each system. I find good agreement with the proper motions derived by the Gaia collaboration for Bootes I and Leo I. The tangential velocities for 14 of the 17 dwarfs are determined to better than 50km/s, more than doubling the sample of such measurements for Milky Way satellite galaxies. The orbital pericenters are well constrained, with a mean value of 38kpc. Only one satellite, Tucana III, is on an orbit passing within 15kpc of the Galactic center, suggesting that the remaining ultra-faint dwarfs are unlikely to have experienced severe tidal stripping. As a group, the ultra-faint dwarfs are on high-velocity, eccentric, retrograde trajectories, with nearly all of them having space motions exceeding 370km/s. A large majority of the objects are currently close to the pericenters of their orbits. In a low-mass (M_vir_=0.9x10^12^M_{sun}_) Milky Way potential, eight out of the 17 galaxies lack well-defined apocenters and appear likely to be on their first infall, indicating that the Milky Way mass may be larger than previously estimated or that many of the ultra-faint dwarfs are associated with the Magellanic Clouds. The median eccentricity of the ultra-faint dwarf orbits is 0.79, similar to the values seen in numerical simulations but distinct from the rounder orbits of the more luminous dwarf spheroidals.
1139. Gaia DR2 quasar and galaxy classification
ID:
ivo://CDS.VizieR/VII/285
Title:
Gaia DR2 quasar and galaxy classification
Short Name:
VII/285
Date:
21 Oct 2021
Publisher:
CDS
Description:
We provide probabilistic quasar and galaxy classifications for 2.7 million sources in Gaia Data Release 2. This has been achieved using a supervised classification method (Gaussian Mixture Models) based only on photometric and astrometric data (8 features) in Gaia-DR2. The model is trained empirically to classify objects into three classes - star, quasar, galaxy - for all objects with G>=14.5mag down to the Gaia magnitude limit of G=21.0mag. We provide the probabilities for being a quasar (pqso) and a galaxy (pgal); the probability of being a star is pstar = 1-(pqso+pgal), and all other Gaia data can be obtained by cross-matching Gaia-DR2 using the source identifier. As our main goal is to identify extragalactic objects, we only report objects with pqso+pgal>0.5. These probabilities incorporate a sensible class prior, namely that quasars are 500 times rarer than stars, and that galaxies 7500 times rarer than stars. See the paper for details of the purity and completeness of samples drawn from this catalogue, and for more details of its construction, contents, and validation.
1140. Gaia DR2 sources in GC and dSph
ID:
ivo://CDS.VizieR/J/A+A/616/A12
Title:
Gaia DR2 sources in GC and dSph
Short Name:
J/A+A/616/A12
Date:
21 Oct 2021
Publisher:
CDS
Description:
The goal of this paper is to demonstrate the outstanding quality of the second data release of the Gaia mission and its power for constraining many different aspects of the dynamics of the satellites of the Milky Way. We focus here on determining the proper motions of 75 Galactic globular clusters, nine dwarf spheroidal galaxies, one ultra-faint system, and the Large and Small Magellanic Clouds. Using data extracted from the Gaia archive, we derived the proper motions and parallaxes for these systems, as well as their uncertainties. We demonstrate that the errors, statistical and systematic, are relatively well understood. We integrated the orbits of these objects in three different Galactic potentials, and characterised their properties. We present the derived proper motions, space velocities, and characteristic orbital parameters in various tables to facilitate their use by the astronomical community. Our limited and straightforward analyses have allowed us for example to (i) determine absolute and very precise proper motions for globular clusters; (ii) detect clear rotation signatures in the proper motions of at least five globular clusters; (iii) show that the satellites of the Milky Way are all on high-inclination orbits, but that they do not share a single plane of motion; (iv) derive a lower limit for the mass of the Milky Way of 9.8^+6.7^_-2.7_x10^11^M_{sun}_ based on the assumption that the Leo~I dwarf spheroidal is bound; (v) derive a rotation curve for the Large Magellanic Cloud based solely on proper motions that is competitive with line-of-sight velocity curves, now using many orders of magnitude more sources; and (vi) unveil the dynamical effect of the bar on the motions of stars in the Large Magellanic Cloud. All these results highlight the incredible power of the Gaia astrometric mission, and in particular of its second data release.