- ID:
- ivo://CDS.VizieR/J/ApJ/833/167
- Title:
- PAndAS view of Andromeda satellites. II.
- Short Name:
- J/ApJ/833/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive analysis of the structural properties and luminosities of the 23 dwarf spheroidal galaxies that fall within the footprint of the Pan-Andromeda Archaeological Survey (PAndAS). These dwarf galaxies represent the large majority of Andromeda's known satellite dwarf galaxies and cover a wide range in luminosity (-11.6<~M_V_<~-5.8 or 10^4.2^<~L<~10^6.5^L_{sun}_) and surface brightness (25.1<~{mu}_0_<~29.3mag/arcsec^2^). We confirm most previous measurements, but we find And XIX to be significantly larger than before (r_h_=3065_-935_^+1065^pc, M_V_=-10.1_-0.4_^+0.8^) and cannot derive parameters for And XXVII as it is likely not a bound stellar system. We also significantly revise downward the luminosities of And XV and And XVI, which are now M_V_~-7.5 or L~10^5^L_{sun}_. Finally, we provide the first detailed analysis of Cas II/And XXX, a fairly faint system (M_V_=-8.0_-0.3_^+0.4^) of typical size (r_h_=270+/-50pc), located in close proximity to the two bright elliptical dwarf galaxies NGC 147 and NGC 185. Combined with the set of homogeneous distances published in an earlier contribution, our analysis dutifully tracks all relevant sources of uncertainty in the determination of the properties of the dwarf galaxies from the PAndAS photometric catalog. We further publish the posterior probability distribution functions of all the parameters we fit for in the form of MCMC chains available online; these inputs should be used in any analysis that aims to remain truthful to the data and properly account for covariance between parameters.
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- ID:
- ivo://CDS.VizieR/J/ApJS/240/19
- Title:
- Parallaxes of late-T and Y dwarfs
- Short Name:
- J/ApJS/240/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present preliminary trigonometric parallaxes of 184 late-T and Y dwarfs using observations from Spitzer (143), the U.S. Naval Observatory (18), the New Technology Telescope (14), and the United Kingdom Infrared Telescope (9). To complete the 20pc census of >=T6 dwarfs, we combine these measurements with previously published trigonometric parallaxes for an additional 44 objects and spectrophotometric distance estimates for another 7. For these 235 objects, we estimate temperatures, sift into five 150K wide T_eff_ bins covering the range 300-1050K, determine the completeness limit for each, and compute space densities. To anchor the high-mass end of the brown dwarf mass spectrum, we compile a list of early- to mid-L dwarfs within 20pc. We run simulations using various functional forms of the mass function passed through two different sets of evolutionary code to compute predicted distributions in T_eff_. The best fit of these predictions to our L, T, and Y observations is a simple power-law model with {alpha}~0.6 (where dN/dM{propto}M^-{alpha}^), meaning that the slope of the field substellar mass function is in rough agreement with that found for brown dwarfs in nearby star-forming regions and young clusters. Furthermore, we find that published versions of the log-normal form do not predict the steady rise seen in the space densities from 1050 to 350K. We also find that the low-mass cutoff to formation, if one exists, is lower than ~5M_Jup_, which corroborates findings in young, nearby moving groups and implies that extremely low-mass objects have been forming over the lifetime of the Milky Way.
- ID:
- ivo://CDS.VizieR/J/PAZh/27/132
- Title:
- Parameters of RR Lyrae Type Variables
- Short Name:
- J/PAZh/27/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The method of statistical parallaxes is applied to a sample of 262 Rrab RR Lyr type variables with published photoelectric photometry, radial velocities, abundances and with known absolute proper motions. The proper motions are adopted from the Hipparcos, PPM, NPM1, and the Four-Million Catalog (Volchkov et al. 1992, Ed. by A.P.Gulyaev and V.V. Nesterov, Mosk. Gos. Univ., Moscow, p. 67) and in the case the last three catalogs are reduced to the Hipparcos system. The parameters of the velocity distribution of halo (U0, V0, W0) = ( -9+/-12, -214+/-10, -16+/-7) km/s and thick-disk (U0, V0, W0) = (-16+/-8, -41+/-7, -18+/-5) km/s RR Lyrae subsamples are inferred as well as the intensity-averaged absolute magnitudes of the corresponding populations: <MV> = 0.77+/-0.10 and <MV> = +1.11+/-0.28 for halo and thickdisk objects, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/374/968
- Title:
- Photometric and kinematic properties of LPVs
- Short Name:
- J/A+A/374/968
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The table gives individual absolute K and IRAS 12 and 25 luminosities of 800 LPVs. They are obtained by applying the Luri-Mennessier (LM, see below) calibration method to a sample composed of stars which are either of type M (O-rich), C (C-rich) or S (C/O~1), including Mira (M), SR (of both type a and b) and L variables. Astrometric data is taken exclusively from the HIPPARCOS Catalogue. Radial velocities are taken from the HIPPARCOS Input Catalogue. K band photometric data are gathered from various sources. Infrared magnitudes are derived from the fluxes measured by the IRAS satellite: m(12)=3.63-2.5log(F(12)) and m(25)=2.07-2.5log(F(25)) The stellar population from which the sample is extracted is assumed to be composed of several distinct groups that can differ in kinematics, luminosity or spatial distribution. The LM method determines the number of significant discriminating groups and produces, for each group, unbiased estimates of the mean parameters of the galactic and luminosity model. In a second step the method uses a Bayesian rule to statistically assign each star to a group. Table gives these assignations denoted as G(G') i.e. to group G in K and G'in IRAS. Three groups are identified in the K band. They can be interpreted as the galactic disk (D), old disk (OD) and extended disk (ED) populations. Four groups are identified in the IRAS bands. They are similar to those identified in the K band except that the old disk group is divided into ``bright'' (ODb) and ``faint'' (ODf) subgroups. Let us add that D, ODb and ED correspond to thick circumstellar envelope stars, while ODf is mainly composed of stars with a thin (or even lacking) envelope.
- ID:
- ivo://CDS.VizieR/J/ApJS/228/9
- Title:
- Physical parameters of ~300000 SDSS-DR12 QSOs
- Short Name:
- J/ApJS/228/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Sloan Digital Sky Survey (SDSS) Quasar Data Release 12 (DR12Q), containing nearly 300000 active galactic nuclei (AGNs), to calculate the monochromatic luminosities at 5100, 3000, and 1350{AA}, derived from the broadband extinction-corrected SDSS magnitudes. After matching these sources to their counterparts from the SDSS Quasar Data Release 7 (DR7Q), we find very high correlations between our luminosities and DR7Q spectra-based luminosities with minute mean offsets (~0.01dex) and dispersions of differences of 0.11, 0.10, and 0.12dex, respectively, across a luminosity range of 2.5dex. We then estimate the black hole (BH) masses of the AGNs using the broad line region radius-disk luminosity relations and the FWHM of the MgII and CIV emission lines, to provide a catalog of 283033 virial BH mass estimates (132451 for MgII, 213071 for CIV, and 62489 for both) along with the estimates of the bolometric luminosity and Eddington ratio for 0.1<z<5.5 and for roughly a quarter of the sky covered by SDSS. The BH mass estimates from Mg II turned out to be closely matched to the ones from DR7Q with a dispersion of differences of 0.34dex across a BH mass range of ~2dex. We uncovered a bias in the derived CIV FWHMs from DR12Q as compared to DR7Q, which we correct empirically. The CIV BH mass estimates should be used with caution because the CIV line is known to cause problems in the estimation of BH mass from single-epoch spectra. Finally, after the FWHM correction, the AGN BH mass estimates from CIV closely match the DR7Q ones (with a dispersion of 0.28dex), and more importantly the MgII and CIV BH masses agree internally with a mean offset of 0.07dex and a dispersion of 0.39dex.
- ID:
- ivo://CDS.VizieR/J/A+A/427/933
- Title:
- Precise temperature of F-K field dwarfs
- Short Name:
- J/A+A/427/933
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Highly precise temperatures (sigma=10-15K) have been determined from line depth ratios for a set of 248 F-K field dwarfs of about solar metallicity (-0.5<[Fe/H]<+0.4), based on high resolution (R=42000), high S/N echelle spectra. A new gap has been discovered in the distribution of stars on the Main Sequence in the temperature range 5560 to 5610K. This gap coincides with a jump in the microturbulent velocity Vt and the well-known Li depression near 5600K in field dwarfs and open clusters. As the principal cause of the observed discontinuities in stellar properties we propose the penetration of the convective zone into the inner layers of stars slightly less massive than the Sun and related to it, a change in the temperature gradient.
- ID:
- ivo://CDS.VizieR/J/AJ/159/25
- Title:
- PS1 light curves and rotation periods of new asteroids
- Short Name:
- J/AJ/159/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The intranight trajectories of asteroids can be approximated by straight lines, and so are their intranight detections. Therefore, the Hough transform, a line detecting algorithm, can be used to connect the line-up detections to find asteroids. We applied this algorithm to a high-cadence Pan-STARRS 1 (PS1) observation, which was originally designed to collect asteroid light curves for rotation period measurements. The algorithm recovered most of the known asteroids in the observing fields and, moreover, discovered 3574 new asteroids with magnitude mainly of 21.5<w_p1_<22.5mag. This magnitude range is equivalent to subkilometer main-belt asteroids (MBAs), which usually lack rotation period measurements due to their faintness. Using the light curves of the 3574 new asteroids, we obtained 122 reliable rotation periods, of which 13 are super-fast rotators (SRFs; i.e., rotation period of <2hr). The required cohesion to survive these SFRs range from tens to thousands of Pa, a value consistent with the known SFRs and the regolith on the Moon and Mars. The higher chance of discovering SFRs here suggests that subkilometer MBAs probably harbor more SFRs.
- ID:
- ivo://CDS.VizieR/J/ApJ/768/37
- Title:
- Radio emission from SDSS quasars
- Short Name:
- J/ApJ/768/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the 1.4GHz NVSS to study radio sources in two color-selected QSO samples: a volume-limited sample of 1313 QSOs defined by M_i_<-23 in the redshift range 0.2<z<0.45 and a magnitude-limited sample of 2471 QSOs with m_r_<=18.5 and 1.8<z<2.5. About 10% were detected above the 2.4mJy NVSS catalog limit and are powered primarily by active galactic nuclei (AGNs). The space density of the low-redshift QSOs evolves as {rho}{prop.to}(1+z)^6^. In both redshift ranges the flux-density distributions and luminosity functions of QSOs stronger than 2.4mJy are power laws, with no features to suggest more than one kind of radio source. Extrapolating the power laws to lower luminosities predicts the remaining QSOs should be extremely radio quiet, but they are not. Most were detected statistically on the NVSS images with median peak flux densities S_p_(mJy/beam){approx}0.3 and 0.05 in the low- and high-redshift samples, corresponding to spectral luminosities log [L_1.4GHz_(W/Hz)]{approx}22.7 and 24.1, respectively. We suggest that the faint radio sources are powered by star formation at rates dM/dt~20M_{sun}_/yr in the moderate luminosity (median <M_i_>{approx}-23.4) low-redshift QSOs and dM/dt~500M_{sun}_/yr in the very luminous (<M_i_>{approx}-27.5) high-redshift QSOs. Such luminous starbursts [<log(L_IR_/L_{sun}_)>~11.2 and 12.6, respectively] are consistent with "quasar mode" accretion in which cold gas flows fuel both AGN and starburst.
- ID:
- ivo://CDS.VizieR/J/AN/341/703
- Title:
- Radio spectral indices of active galaxies
- Short Name:
- J/AN/341/703
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we investigate radio properties of active galaxies taken from the reference Veron-Cetty & Veron (2010, Cat. VII/258) catalog. The galaxies are limited to magnitudes in the range of 12^m^-19^m^. We have cross-correlated the list with radio catalogs and selected those galaxies that have data on six or more radio fluxes at different wavelengths. As a result, we have 198 galaxies that satisfy these conditions. Using SDSS DR15, we have obtained 96 spectroscopic identifications of the 198 objects. After the classification, 85% of the 96 objects have changed their types. Available data on the classification of these objects and our classification showed that 56.7% of them are Seyfert galaxies. For all the objects, we have built radio spectra and estimated radio spectral indices. As a result, we obtain {alpha}>=-0.6089+/-0.056> ({alpha}_Seyfert_=-0.6013+/-0.027, {alpha}_LINER_=-0.5955+/-0.025, {alpha}_HII_=-0.6672+/-0.039, {alpha}_Comp._=-0.7128+/-0.043). We discuss the radio properties of active galaxies based on their radio spectral indices.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/196
- Title:
- REQUIEM survey. I. Ly{alpha} halos around QSOs
- Short Name:
- J/ApJ/887/196
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The discovery of quasars a few hundred megayears after the Big Bang represents a major challenge to our understanding of black holes as well as galaxy formation and evolution. Quasars' luminosity is produced by extreme gas accretion onto black holes, which have already reached masses of M_BH_>10^9^M_{sun}_ by z~6. Simultaneously, their host galaxies form hundreds of stars per year, using up gas in the process. To understand which environments are able to sustain the rapid formation of these extreme sources, we started a Very Large Telescope/Multi-Unit Spectroscopic Explorer (MUSE) effort aimed at characterizing the surroundings of a sample of 5.7<z<6.6 quasars, which we have dubbed the Reionization Epoch QUasar InvEstigation with MUSE (REQUIEM) survey. We here present results of our searches for extended Ly{alpha} halos around the first 31 targets observed as part of this program. Reaching 5{sigma} surface brightness limits of 0.1-1.1x10^-17^erg/s/cm^2^/arcsec^2^ over a 1arcsec^2^ aperture, we were able to unveil the presence of 12 Ly{alpha} nebulae, eight of which are newly discovered. The detected nebulae show a variety of emission properties and morphologies with luminosities ranging from 8x10^42^ to 2x10^44^erg/s, FWHMs between 300 and 1700km/s, sizes <30pkpc, and redshifts consistent with those of the quasar host galaxies. As the first statistical and homogeneous investigation of the circumgalactic medium of massive galaxies at the end of the reionization epoch, the REQUIEM survey enables the study of the evolution of the cool gas surrounding quasars in the first 3Gyr of the universe. A comparison with the extended Ly{alpha} emission observed around bright (M_1450_<~-25mag) quasars at intermediate redshift indicates little variations on the properties of the cool gas from z~6 to z~3, followed by a decline in the average surface brightness down to z~2.
