- ID:
- ivo://CDS.VizieR/J/ApJ/845/157
- Title:
- IMF in 3 low-redshift strong lenses from SNELLS
- Short Name:
- J/ApJ/845/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new observations of the three nearest early-type galaxy (ETG) strong lenses discovered in the SINFONI Nearby Elliptical Lens Locator Survey (SNELLS). Based on their lensing masses, these ETGs were inferred to have a stellar initial mass function (IMF) consistent with that of the Milky Way, not the bottom-heavy IMF that has been reported as typical for high-{sigma} ETGs based on lensing, dynamical, and stellar population synthesis techniques. We use these unique systems to test the consistency of IMF estimates derived from different methods. We first estimate the stellar M*/L using lensing and stellar dynamics. We then fit high-quality optical spectra of the lenses using an updated version of the stellar population synthesis models developed by Conroy & van Dokkum. When examined individually, we find good agreement among these methods for one galaxy. The other two galaxies show 2-3{sigma} tension with lensing estimates, depending on the dark matter contribution, when considering IMFs that extend to 0.08M_{sun}_. Allowing a variable low-mass cutoff or a nonparametric form of the IMF reduces the tension among the IMF estimates to <2{sigma}. There is moderate evidence for a reduced number of low-mass stars in the SNELLS spectra, but no such evidence in a composite spectrum of matched-{sigma} ETGs drawn from the SDSS. Such variation in the form of the IMF at low stellar masses (m<~0.3M_{sun}_), if present, could reconcile lensing/dynamical and spectroscopic IMF estimates for the SNELLS lenses and account for their lighter M*/L relative to the mean matched-{sigma} ETG. We provide the spectra used in this study to facilitate future comparisons.
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- ID:
- ivo://CDS.VizieR/J/AJ/152/8
- Title:
- Impact of stellar multiplicity on planetary systems I.
- Short Name:
- J/AJ/152/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The dynamical influence of binary companions is expected to profoundly influence planetary systems. However, the difficulty of identifying planets in binary systems has left the magnitude of this effect uncertain; despite numerous theoretical hurdles to their formation and survival, at least some binary systems clearly host planets. We present high-resolution imaging of 382 Kepler Objects of Interest (KOIs) obtained using adaptive-optics imaging and nonredundant aperture-mask interferometry on the Keck II telescope. Among the full sample of 506 candidate binary companions to KOIs, we super-resolve some binary systems to projected separations of <5au, showing that planets might form in these dynamically active environments. However, the full distribution of projected separations for our planet-host sample more broadly reveals a deep paucity of binary companions at solar-system scales. For a field binary population, we should have found 58 binary companions with projected separation {rho}<50au and mass ratio q>0.4; we instead only found 23 companions (a 4.6{sigma} deficit), many of which must be wider pairs that are only close in projection. When the binary population is parametrized with a semimajor axis cutoff a_cut_ and a suppression factor inside that cutoff S_bin_, we find with correlated uncertainties that inside a_cut_=47_-23_^+59^au, the planet occurrence rate in binary systems is only S_bin_=0.34_-0.15_^+0.14^ times that of wider binaries or single stars. Our results demonstrate that a fifth of all solar-type stars in the Milky Way are disallowed from hosting planetary systems due to the influence of a binary companion.
- ID:
- ivo://CDS.VizieR/J/MNRAS/398/109
- Title:
- Imperial IRAS-FSC redshift catalogue (IIFSCz)
- Short Name:
- J/MNRAS/398/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalogue, the Imperial IRAS-FSC Redshift Catalogue (IIFSCz), of 60303 galaxies selected at 60um from the IRAS Faint Source Catalogue (FSC). The IIFSCz consists of accurate position, optical, near-infrared and/or radio identifications, spectroscopic redshift (if available) or photometric redshift (if possible), predicted far-infrared (FIR) and submillimetre (submm) fluxes ranging from 12 to 1380um based upon the best-fitting infrared template. About 55% of the galaxies in the IIFSCz have spectroscopic redshifts, and a further 20% have photometric redshifts obtained through either the training set or the template-fitting method. For S(60)>0.36Jy, the 90% completeness limit of the FSC, 90% of the sources have either spectroscopic or photometric redshifts. Scientific applications of the IIFSCz include validation of current and forthcoming infrared and submm/mm surveys such as AKARI, Planck and Herschel, follow-up studies of rare source populations, large-scale structure and galaxy bias, local multiwavelength luminosity functions and source counts. The catalogue is publicly available at http://astro.imperial.ac.uk/~mrr/fss/.
- ID:
- ivo://CDS.VizieR/J/MNRAS/445/845
- Title:
- Implications of the Galactic aberration for CRF
- Short Name:
- J/MNRAS/445/845
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- During the last few years, much attention has been paid to the astrometric implications of the galactic aberration in proper motions (GA). This effect causes systematic errors in astrometric measurements at a {mu}as level. Some authors consider it so serious that it requires redefinition of the Celestial Reference Frame (CRF). We argue that such attention to the GA is exaggerated too much. It is just a small astrometric correction that must be taken into account during highly accurate astrometric and geodetic data processing. The accuracy of this correction depends on the accuracy of the Galactic rotation parameters and, for most applications, on the accuracy of the rotation matrix between Galactic and equatorial systems. Our analysis has shown that our current knowledge of these two factors is sufficient to compute the correction of the GA with an accuracy better than 10 per cent. The remaining effect at the level of a few tenths {mu}as/yr is negligible nowadays. Another consequence of introducing the GA correction is the necessity to return to classical astrometric modelling of the extragalactic radio source position - derived by very-long-baseline interferometry (VLBI) - by the linear trend model. Changing the current paradigm of the VLBI-derived CRF, based on the assumption of zero motion of radio sources, to classical one leads to bias in the radio source positions of up to several tens of {mu}as for a catalogue at epoch J2000.0.
- ID:
- ivo://CDS.VizieR/J/A+A/548/A16
- Title:
- Improved astrometry bor BE74 stars
- Short Name:
- J/A+A/548/A16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate astrometry is required to reliably cross-match 20th-century catalogues against 21st-century surveys. The present work aims to provide such astrometry for the 625 entries of the Bohannan & Epps (BE74; 1974A&AS...18...47B) catalogue of H{alpha} emission-line stars. BE74 targets have been individually identified in digital images and, in most cases, unambiguously matched to entries in the UCAC4 (I/322) astrometric catalogue.
- ID:
- ivo://CDS.VizieR/J/ApJ/686/749
- Title:
- Improved cosmological constraints from SNe
- Short Name:
- J/ApJ/686/749
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new compilation of Type Ia supernovae (SNe Ia), a new data set of low-redshift nearby-Hubble-flow SNe, and new analysis procedures to work with these heterogeneous compilations. This "Union" compilation of 414 SNe Ia, which reduces to 307 SNe after selection cuts, includes the recent large samples of SNe Ia from the Supernova Legacy Survey and ESSENCE Survey, the older data sets, as well as the recently extended data set of distant supernovae observed with the Hubble Space Telescope (HST). A single, consistent, and blind analysis procedure is used for all the various SN Ia subsamples, and a new procedure is implemented that consistently weights the heterogeneous data sets and rejects outliers. We present the latest results from this Union compilation and discuss the cosmological constraints from this new compilation and its combination with other cosmological measurements (CMB and BAO).
- ID:
- ivo://CDS.VizieR/J/ApJ/659/122
- Title:
- Improved distances to type Ia supernovae
- Short Name:
- J/ApJ/659/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an updated version of the multicolor light-curve shape method to measure distances to Type Ia supernovae (SNe Ia), incorporating new procedures for K-correction and extinction corrections. We also develop a simple model to disentangle intrinsic color variations and reddening by dust and expand the method to incorporate U-band light curves and to more easily accommodate prior constraints on any of the model parameters. We apply this method to 133 nearby SNe Ia, including 95 objects in the Hubble flow (cz>=2500km/s), which give an intrinsic dispersion of less than 7% in distance. The Hubble flow sample, which is of critical importance to all cosmological uses of SNe Ia, is the largest ever presented with homogeneous distances.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/33
- Title:
- Improved & expanded membership catalog for NGC752
- Short Name:
- J/ApJ/862/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nearby open cluster NGC 752 presents a rare opportunity to study stellar properties at ages >1Gyr. However, constructing a membership catalog for it is challenging; most surveys have been limited to identifying its giants and dwarf members earlier than mid-K. We supplement past membership catalogs with candidates selected with updated photometric and proper-motion criteria, generating a list of 258 members, a >50% increase over previous catalogs. Using a Bayesian framework to fit MESA Isochrones & Stellar Tracks evolutionary models to literature photometry and the Tycho-Gaia Astrometric Solution data available for 59 cluster members, we infer the age of and distance to NGC 752: 1.34+/-0.06Gyr and 438_-6_^+8^pc. We also report the results of our optical monitoring of the cluster using the Palomar Transient Factory. We obtain rotation periods for 12 K and M cluster members, the first periods measured for such low-mass stars with a well-constrained age >1Gyr. We compare these new periods to data from the younger clusters Praesepe and NGC 6811, and to a theoretical model for angular momentum loss, to examine stellar spin-down for low-mass stars over their first 1.3Gyr. While on average NGC 752 stars are rotating more slowly than their younger counterparts, the difference is not significant. Finally, we use our spectroscopic observations to measure H{alpha} for cluster stars, finding that members earlier than ~M2 are magnetically inactive, as expected at this age. Forthcoming Gaia data should solidify and extend the membership of NGC 752 to lower masses, thereby increasing its importance for studies of low-mass stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/746/154
- Title:
- Improved kinematic parallaxes for Sco-Cen members
- Short Name:
- J/ApJ/746/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the ages and star formation history of the F-type stars in the Upper Scorpius (US), Upper Centaurus-Lupus (UCL), and Lower Centaurus-Crux (LCC) subgroups of Scorpius-Centaurus (Sco-Cen), the nearest OB association. Our parent sample is the kinematically selected Hipparcos sample of de Zeeuw et al. (1999, Cat. J/AJ/117/354), restricted to the 138 F-type members. We have obtained classification-resolution optical spectra and have also determined the spectroscopic accretion disk fraction. With Hipparcos and 2MASS photometry, we estimate the reddening and extinction for each star and place the candidate members on a theoretical H-R diagram. For each subgroup we construct empirical isochrones and compare to published evolutionary tracks.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/15
- Title:
- Improved 2Ms and 250ks Chandra catalogs
- Short Name:
- J/ApJS/224/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present improved point-source catalogs for the 2Ms Chandra Deep Field-North (CDF-N) and the 250ks Extended Chandra Deep Field-South (E-CDF-S) Surveys, implementing a number of recent improvements in Chandra source-cataloging methodology. For CDF-N/E-CDF-S, we provide a main catalog that contains 683/1003 X-ray sources detected with wavdetect at a false-positive probability threshold of 10^-5^ that also satisfy a binomial-probability source-selection criterion of P<=0.004/P<0.002. Such an approach maximizes the number of reliable sources detected: a total of 196/275 main-catalog sources are new compared to the Alexander+ (2003, J/AJ/126/539) CDF-N/Lehmer+ (2005, J/ApJS/161/21) E-CDF-S main catalogs. We also provide CDF-N/E-CDF-S supplementary catalogs that consist of 72/56 sources detected at the same wavdetect threshold and having P of 0.004-0.1/0.002-0.1 and Ks<=22.9/Ks<=22.3mag counterparts. For all ~1800 CDF-N and E-CDF-S sources, including the ~500 newly detected ones (these being generally fainter and more obscured), we determine X-ray source positions utilizing centroid and matched-filter techniques; we also provide multiwavelength identifications, apparent magnitudes of counterparts, spectroscopic and/or photometric redshifts, basic source classifications, and estimates of observed active galactic nucleus and galaxy source densities around respective field centers. Simulations show that both the CDF-N and E-CDF-S main catalogs are highly reliable and reasonably complete. Background and sensitivity analyses indicate that the on-axis mean flux limits reached represent a factor of ~1.5-2.0 improvement over the previous CDF-N and E-CDF-S limits. We make our data products publicly available.