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3701. Low-mass stars in Coma Ber
ID:
ivo://CDS.VizieR/J/A+A/544/A111
Title:
Low-mass stars in Coma Ber
Short Name:
J/A+A/544/A111
Date:
21 Oct 2021
Publisher:
CDS
Description:
Little is known about the population of the Coma Berenices open cluster (age~500Myr) below 0.2M_{sun}_, and statistics show that there is a prominent deficit of very low-mass objects in this mass range compared to younger open clusters with ages of <250Myr. We search for very low-mass stars and substellar objects (brown dwarfs) in the Coma open cluster to derive the present-day cluster mass function below 0.2M_{sun}_.
3702. Low-mass stars in M45 and M44
ID:
ivo://CDS.VizieR/J/MNRAS/342/1241
Title:
Low-mass stars in M45 and M44
Short Name:
J/MNRAS/342/1241
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present near-infrared J-, H- and K-band photometry and optical spectroscopy of low-mass star and brown dwarf (BD) candidates in the Pleiades and Praesepe open clusters. We flag non-members from their position in K, I-K and J, J-K colour-magnitude diagrams (CMDs), and J-H, H-K two-colour diagrams.
3703. Low-mass stars in 25 Ori group and Orion OB1a
ID:
ivo://CDS.VizieR/J/AJ/154/14
Title:
Low-mass stars in 25 Ori group and Orion OB1a
Short Name:
J/AJ/154/14
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Orion OB1a sub-association is a rich low-mass star (LMS) region. Previous spectroscopic studies have confirmed 160 LMSs in the 25 Orionis stellar group (25 Ori), which is the most prominent overdensity of Orion OB1a. Nonetheless, the current census of the 25 Ori members is estimated to be lower than 50% complete, leaving a large number of members to be still confirmed. We retrieved 172 low-resolution stellar spectra in Orion OB1a observed as ancillary science in the SDSS-III/BOSS survey, for which we classified their spectral types and determined physical parameters. To determine memberships, we analyzed the H{alpha} emission, LiI{lambda}6708 absorption, and NaI{lambda}{lambda}8183,8195 absorption as youth indicators in stars classified as M type. We report 50 new LMSs spread across the 25 Orionis, ASCC18, and ASCC20 stellar groups with spectral types from M0 to M6, corresponding to a mass range of 0.10{<=}m/M_{Sun}_{<=}0.58. This represents an increase of 50% in the number of known LMSs in the area and a net increase of 20% in the number of 25 Ori members in this mass range. Using parallax values from the Gaia DR1 catalog, we estimated the distances to these three stellar groups and found that they are all co-distant, at 338+/-66pc. We analyzed the spectral energy distributions of these LMSs and classified their disks into evolutionary classes. Using H-R diagrams, we found a suggestion that 25 Ori could be slightly older than the other two observed groups in Orion OB1a.
3704. Low-mass stars in {sigma} Ori and {lambda} Ori
ID:
ivo://CDS.VizieR/J/A+A/488/167
Title:
Low-mass stars in {sigma} Ori and {lambda} Ori
Short Name:
J/A+A/488/167
Date:
21 Oct 2021
Publisher:
CDS
Description:
We performed a detailed membership selection and studied the accretion properties of low-mass stars in the two apparently very similar young (1-10Myr) clusters {sigma} Ori and {lambda} Ori. We observed 98 and 49 low-mass (0.2-1.0M_{sun}_stars in {sigma} Ori and {lambda} Ori respectively, using the multi-object optical spectrograph FLAMES at the VLT, with the high-resolution (R~17000) HR15N grating (6470-6790{AA}). We used radial velocities, Li and H{alpha} to establish cluster membership and H{alpha} and other optical emission lines to analyze the accretion properties of members. We identified 65 and 45 members of the {sigma} Ori and {lambda} Ori clusters, respectively, and discovered 16 new candidate binary systems.
3705. Low-mass stars in the Cepheus OB2 region
ID:
ivo://CDS.VizieR/J/AJ/128/805
Title:
Low-mass stars in the Cepheus OB2 region
Short Name:
J/AJ/128/805
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first identification of low-mass (spectral types K-M) stars in the young clusters Tr37 and NGC7160, members of the CepOB2 association. This is part of a program to follow the evolution of protoplanetary accretion disks through the ages thought to be crucial to understanding disk dissipation and planet formation (~3-10Myr). Combining optical photometry and optical spectroscopy, we have identified ~40 members in Tr37 and ~15 in NGC7160, using several independent tests for determining the membership (optical colors, optical variability, H{alpha} emission, and Li{lambda}6707 absorption).
3706. Low-mass stars in Trumpler 37
ID:
ivo://CDS.VizieR/J/A+A/559/A3
Title:
Low-mass stars in Trumpler 37
Short Name:
J/A+A/559/A3
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a study of accretion and protoplanetary disks around M-type stars in the 4 Myr-old cluster Tr 37. With a well-studied solar-type population, Tr 37 is a benchmark for disk evolution. We used low-resolution spectroscopy to identify and classify 141 members (78 new ones) and 64 probable members, mostly M-type stars. H{alpha} emission provides information about accretion. Optical, 2MASS, Spitzer, and WISE data are used to trace the spectral energy distributions (SEDs) and search for disks. We construct radiative transfer models to explore the structures of full-disks, pre-transition, transition, and dust-depleted disks.
3707. Low-mass stars spectroscopy in NGC 2516
ID:
ivo://CDS.VizieR/J/MNRAS/423/2966
Title:
Low-mass stars spectroscopy in NGC 2516
Short Name:
J/MNRAS/423/2966
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present far-red, intermediate-resolution spectroscopy of 572 photometrically selected, low-mass stars (0.2<M/M_{sun}_<0.7) in the young open cluster NGC 2516, using the FLAMES spectrograph at the Very Large Telescope. Precise radial velocities confirm membership for 210 stars that have published rotation periods from spot-modulated light curves and for another 144 stars in which periodic modulation could not be found. The two subsamples are compared and no significant differences are found between their positions in colour-magnitude diagrams, the distribution of their projected equatorial velocities or their levels of chromospheric activity.
3708. Low-redshift quasars in SDSS Stripe 82
ID:
ivo://CDS.VizieR/J/MNRAS/440/476
Title:
Low-redshift quasars in SDSS Stripe 82
Short Name:
J/MNRAS/440/476
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a photometrical and morphological study of the properties of low-redshift (z<0.5) quasars based on a large and homogeneous data set of objects derived from the Sloan Digital Sky Survey Data Release 7. This study over number by a factor of ~5 any other previous study of quasi-stellar object (QSO) host galaxies at low redshift undertaken either on ground or on space surveys. We used ~400 quasars that were imaged in the SDSS Stripe 82 that is up to 2mag deeper than standard Sloan images. For these quasars we undertake a study of the host galaxies and of their environments. In this paper we report the results for the quasar hosts. We are able to detect the host galaxy for more than 3/4 of the whole data set and characterize the properties of their hosts. We found that QSO hosts are dominated by luminous galaxies of absolute magnitude M*-3<M(R)<M*. For the unresolved objects we computed an upper limit to the host luminosity. For each well-resolved quasar we are also able to characterize the morphology of the host galaxy that turn out to be more complex than what found in previous studies. QSOs are hosted in a variety of galaxies from pure ellipticals to complex/composite morphologies that combine spheroids, disc, lens and halo. The black hole (BH) mass of the quasar, estimated from the spectral properties of the nuclei, is poorly correlated with the total luminosity of the host galaxy. However, taking into account only the bulge component we found a significant correlation between the BH mass and the bulge luminosity of the host.
3709. Low-redshift Type-Ia supernovae
ID:
ivo://CDS.VizieR/J/AJ/139/120
Title:
Low-redshift Type-Ia supernovae
Short Name:
J/AJ/139/120
Date:
21 Oct 2021
Publisher:
CDS
Description:
An analysis of the first set of low-redshift (z<0.08) Type Ia supernovae (SNe Ia) monitored by the Carnegie Supernova Project between 2004 and 2006 is presented. The data consist of well-sampled, high-precision optical (ugriBV) and near-infrared (NIR; YJHKs) light curves in a well-understood photometric system.
3710. Low-resolution SED templates for AGNs and galaxies
ID:
ivo://CDS.VizieR/J/ApJ/713/970
Title:
Low-resolution SED templates for AGNs and galaxies
Short Name:
J/ApJ/713/970
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a set of low-resolution empirical spectral energy distribution (SED) templates for active galactic nuclei (AGNs) and galaxies in the wavelength range from 0.03um to 30um based on the multi-wavelength photometric observations of the NOAO Deep-Wide Field Survey Bootes field and the spectroscopic observations of the AGN and Galaxy Evolution Survey. Our training sample is comprised of 14448 galaxies in the redshift range 0<~z<~1 and 5347 likely AGNs in the range 0<~z<~5.58. The galaxy templates correspond to the SED templates presented in 2008 by Assef et al. (Cat. J/ApJ/676/286) extended into the UV and mid-IR by the addition of FUV and NUV GALEX and MIPS 24um data for the field. We use our templates to determine photometric redshifts for galaxies and AGNs. While they are relatively accurate for galaxies ({sigma}_z_/(1+z)=0.04, with 5% outlier rejection), their accuracies for AGNs are a strong function of the luminosity ratio between the AGN and galaxy components. Somewhat surprisingly, the relative luminosities of the AGN and its host are well determined even when the photometric redshift is significantly in error. Finally, we use our templates to predict the color-color distribution of sources in the upcoming Wide-Field Infrared Survey Explorer (WISE) mission and define a color criterion to select AGNs analogous to those developed for IRAC photometry. We estimate that in between 640000 and 1700000 AGNs will be identified by these criteria, but without additional information, WISE-selected quasars will have serious completeness problems for z>~3.4.