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111. An optical overview of blazars with LAMOST. I.
ID:
ivo://CDS.VizieR/J/AJ/161/196
Title:
An optical overview of blazars with LAMOST. I.
Short Name:
J/AJ/161/196
Date:
16 Mar 2022 11:51:00
Publisher:
CDS
Description:
The extragalactic {gamma}-rays sky observed by the Fermi Large Area Telescope (LAT) is dominated by blazars. In the fourth release of the Fermi LAT Point Source Catalog (4FGL) are sources showing a multifrequency behavior similar to that of blazars but lacking an optical spectroscopic confirmation of their nature, known as blazar candidates of uncertain type (BCUs). We aim at confirming the blazar nature of BCUs and test if new optical spectroscopic observations can reveal spectral features, allowing us to get a redshift estimate for known BL Lac objects. We also aim to search for and discover changing-look blazars (i.e., blazars that show a different classification at different epochs). We carry out an extensive search for optical spectra available in the Large Sky Area Multi-object Fibre Spectroscopic Telescope (LAMOST) Data Release 5 (DR5) archive. We select sources out of the 4FGL catalog, the list of targets from our follow-up spectroscopic campaign of unidentified or unassociated {gamma}-ray sources, and the multifrequency catalog of blazars: the Roma-BZCAT. We select a total of 392 spectra. We also compare some of the LAMOST spectra with those available in the literature. We classify 20 BCUs confirming their blazar-like nature. Then we obtain 15 new redshift estimates for known blazars. We discover 26 transitional (i.e., changing-look) blazars that changed their classification. Finally, we are able to confirm the blazar-like nature of six BL Lac candidates. All remaining sources analyzed agree with previous classifications. BL Lac objects are certainly the most elusive type of blazars in the {gamma}-ray extragalactic sky.
112. An updated catalog of M31 globular-like clusters
ID:
ivo://CDS.VizieR/J/ApJ/725/200
Title:
An updated catalog of M31 globular-like clusters
Short Name:
J/ApJ/725/200
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an updated UBVRI photometric catalog containing 970 objects in the field of M31, selected from the Revised Bologna Catalog (RBC v.4.0), including 965, 967, 965, 953, and 827 sources in the individual UBVRI bands, respectively, of which 205, 123, 14, 126, and 109 objects do not have previously published photometry. Photometry is performed using archival images from the Local Group Galaxies Survey, which covers 2.2deg^2^ along the major axis of M31. Detailed comparisons show that our photometry is fully consistent with previous measurements in all filters. We focus on 445 confirmed "globular-like" clusters and candidates, comprising typical globular and young massive clusters. The ages and masses of these objects are derived by comparing their observed spectral-energy distributions with simple stellar population synthesis. Approximately half of the clusters are younger than 2Gyr, suggesting that there has been significant recent active star formation in M31, which is consistent with previous results.
113. AO imaging of KOIs with gas giant planets
ID:
ivo://CDS.VizieR/J/ApJ/806/248
Title:
AO imaging of KOIs with gas giant planets
Short Name:
J/ApJ/806/248
Date:
21 Oct 2021
Publisher:
CDS
Description:
As hundreds of gas giant planets have been discovered, we study how these planets form and evolve in different stellar environments, specifically in multiple stellar systems. In such systems, stellar companions may have a profound influence on gas giant planet formation and evolution via several dynamical effects such as truncation and perturbation. We select 84 Kepler Objects of Interest (KOIs) with gas giant planet candidates. We obtain high-angular resolution images using telescopes with adaptive optics (AO) systems. Together with the AO data, we use archival radial velocity data and dynamical analysis to constrain the presence of stellar companions. We detect 59 stellar companions around 40 KOIs for which we develop methods of testing their physical association. These methods are based on color information and galactic stellar population statistics. We find evidence of suppressive planet formation within 20 AU by comparing stellar multiplicity. The stellar multiplicity rate (MR) for planet host stars is 0_-0_^+5^% within 20 AU. In comparison, the stellar MR is 18%+/-2% for the control sample, i.e., field stars in the solar neighborhood. The stellar MR for planet host stars is 34%+/-8% for separations between 20 and 200 AU, which is higher than the control sample at 12%+/-2%. Beyond 200 AU, stellar MRs are comparable between planet host stars and the control sample. We discuss the implications of the results on gas giant planet formation and evolution.
114. APASS BVgri photometry of RAVE stars. I. Data
ID:
ivo://CDS.VizieR/J/AJ/148/81
Title:
APASS BVgri photometry of RAVE stars. I. Data
Short Name:
J/AJ/148/81
Date:
21 Oct 2021
Publisher:
CDS
Description:
We provide AAVSO Photometric All-Sky Survey (APASS) photometry in the Landolt BV and Sloan g'r'i' bands for all 425743 stars included in the fourth RAVE Data Release. The internal accuracy of the APASS photometry of RAVE stars, expressed as the error of the mean of data obtained and separately calibrated over a median of four distinct observing epochs and distributed between 2009 and 2013, is 0.013, 0.012, 0.012, 0.014, and 0.021mag for the B, V, g', r', and i' bands, respectively. The equally high external accuracy of APASS photometry has been verified on secondary Landolt and Sloan photometric standard stars not involved in the APASS calibration process and on a large body of literature data on field and cluster stars, confirming the absence of offsets and trends. Compared with the Carlsberg Meridian Catalog (CMC-15), APASS astrometry of RAVE stars is accurate to a median value of 0.098arcsec. Brightness distribution functions for the RAVE stars have been derived in all bands. APASS photometry of RAVE stars, augmented by 2MASS JHK infrared data, has been {chi}^2^ fitted to a densely populated synthetic photometric library designed to widely explore temperature, surface gravity, metallicity, and reddening. Resulting T_eff_ and E_B-V_, computed over a range of options, are provided and discussed, and will be kept updated in response to future APASS and RAVE data releases. In the process, we find that the reddening caused by a homogeneous slab of dust, extending for 140pc on either side of the Galactic plane and responsible for E_B-V_^poles^=0.036+/-0.002 at the Galactic poles, is a suitable approximation of the actual reddening encountered at Galactic latitudes|b|>=25{deg}.
115. APOGEE and Gaia DR2 analysis of IC 166
ID:
ivo://CDS.VizieR/J/AJ/156/94
Title:
APOGEE and Gaia DR2 analysis of IC 166
Short Name:
J/AJ/156/94
Date:
21 Oct 2021
Publisher:
CDS
Description:
IC 166 is an intermediate-age open cluster (OC) (~1 Gyr) that lies in the transition zone of the metallicity gradient in the outer disk. Its location, combined with our very limited knowledge of its salient features, make it an interesting object of study. We present the first high-resolution spectroscopic and precise kinematical analysis of IC 166, which lies in the outer disk with R_GC_~12.7 kpc. High-resolution H-band spectra were analyzed using observations from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment survey. We made use of the Brussels Automatic Stellar Parameter code to provide chemical abundances based on a line-by-line approach for up to eight chemical elements (Mg, Si, Ca, Ti, Al, K, Mn, and Fe). The {alpha}-element (Mg, Si, Ca, and whenever available Ti) abundances, and their trends with Fe abundances have been analyzed for a total of 13 high-likelihood cluster members. No significant abundance scatter was found in any of the chemical species studied. Combining the positional, heliocentric distance, and kinematic information, we derive, for the first time, the probable orbit of IC 166 within a Galactic model including a rotating boxy bar, and found that it is likely that IC 166 formed in the Galactic disk, supporting its nature as an unremarkable Galactic OC with an orbit bound to the Galactic plane.
116. APOGEE2-N NIR spectra of B-type stars
ID:
ivo://CDS.VizieR/J/ApJ/894/5
Title:
APOGEE2-N NIR spectra of B-type stars
Short Name:
J/ApJ/894/5
Date:
19 Jan 2022 00:59:33
Publisher:
CDS
Description:
We present a semi-empirical spectral classification scheme for normal B-type stars using near-infrared (NIR) spectra (1.5-1.7{mu}m) from the Sloan Digital Sky Survey Apache Point Observatory Galaxy Evolution Experiment (APOGEE2)-N data release 14 (DR14) database. The main motivation for working with B-type stars is their importance in the evolution of young stellar clusters; however, we also take advantage of having a numerous sample (316 stars) of B-type star candidates in APOGEE2-N, for which we also have optical (3600-9100{AA}) counterparts from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey. By first obtaining an accurate spectral classification of the sources using the LAMOST DR3 spectra and the canonical spectral classification scheme, we found a linear relation between optical spectral types and the equivalent widths of the hydrogen lines of the Brackett series in the APOGEE2-N NIR spectra. This relation extends smoothly from a similar relation for O and early B stars found by Roman-Lopes+ (2018, J/ApJ/855/68). This way, we obtain a catalog of B-type sources with features in both the optical and NIR and a classification scheme refined down to one spectral subclass.
117. APOGEE stars distance and extinction
ID:
ivo://CDS.VizieR/J/MNRAS/460/3179
Title:
APOGEE stars distance and extinction
Short Name:
J/MNRAS/460/3179
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using a Bayesian technology, we derived distances and extinctions for over 100000 red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey by taking into account spectroscopic constraints from the APOGEE stellar parameters and photometric constraints from Two Micron All-Sky Survey, as well as a prior knowledge on the Milky Way. Derived distances are compared with those from four other independent methods, the Hipparcos parallaxes, star clusters, APOGEE red clump stars, and asteroseismic distances from APOKASC and Stromgren survey for Asteroseismology and Galactic Archaeology catalogues. These comparisons covers four orders of magnitude in the distance scale from 0.02 to 20kpc. The results show that our distances agree very well with those from other methods: the mean relative difference between our Bayesian distances and those derived from other methods ranges from -4.2 per cent to +3.6 per cent, and the dispersion ranges from 15 per cent to 25 per cent. The extinctions towards all stars are also derived and compared with those from several other independent methods: the Rayleigh-Jeans Colour Excess (RJCE) method, Gonzalez's 2D extinction map, as well as 3D extinction maps and models. The comparisons reveal that, overall, estimated extinctions agree very well, but RJCE tends to overestimate extinctions for cool stars and objects with low logg.
118. APOGEE-2 survey of Orion Complex. II.
ID:
ivo://CDS.VizieR/J/AJ/156/84
Title:
APOGEE-2 survey of Orion Complex. II.
Short Name:
J/AJ/156/84
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of spectroscopic and astrometric data from APOGEE-2 and Gaia DR2 (Cat. I/345) to identify structures toward the Orion Complex. By applying a hierarchical clustering algorithm to the six-dimensional stellar data, we identify spatially and/or kinematically distinct groups of young stellar objects with ages ranging from 1 to 12 Myr. We also investigate the star-forming history within the Orion Complex and identify peculiar subclusters. With this method we reconstruct the older populations in the regions that are currently largely devoid of molecular gas, such as Orion C (which includes the {sigma} Ori cluster) and Orion D (the population that traces Ori OB1a, OB1b, and Orion X). We report on the distances, kinematics, and ages of the groups within the Complex. The Orion D group is in the process of expanding. On the other hand, Orion B is still in the process of contraction. In {lambda} Ori the proper motions are consistent with a radial expansion due to an explosion from a supernova; the traceback age from the expansion exceeds the age of the youngest stars formed near the outer edges of the region, and their formation would have been triggered when they were halfway from the cluster center to their current positions. We also present a comparison between the parallax and proper-motion solutions obtained by Gaia DR2 and those obtained toward star-forming regions by the Very Long Baseline Array.
119. APOGEE-2 survey of Orion Complex (OSFC). I.
ID:
ivo://CDS.VizieR/J/ApJS/236/27
Title:
APOGEE-2 survey of Orion Complex (OSFC). I.
Short Name:
J/ApJS/236/27
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Orion Star-forming Complex (OSFC) is a central target for the APOGEE-2 Young Cluster Survey. Existing membership catalogs span limited portions of the OSFC, reflecting the difficulty of selecting targets homogeneously across this extended, highly structured region. We have used data from wide-field photometric surveys to produce a less biased parent sample of young stellar objects (YSOs) with infrared (IR) excesses indicative of warm circumstellar material or photometric variability at optical wavelengths across the full 420deg^2^ extent of the OSFC. When restricted to YSO candidates with H<12.4, to ensure S/N~100 for a six-visit source, this uniformly selected sample includes 1307 IR excess sources selected using criteria vetted by Koenig & Leisawitz (2014ApJ...791..131K) and 990 optical variables identified in the Pan-STARRS1 3{pi} survey: 319 sources exhibit both optical variability and evidence of circumstellar disks through IR excess. Objects from this uniformly selected sample received the highest priority for targeting, but required fewer than half of the fibers on each APOGEE-2 plate. We filled the remaining fibers with previously confirmed and new color-magnitude selected candidate OSFC members. Radial velocity measurements from APOGEE-1 and new APOGEE-2 observations taken in the survey's first year indicate that ~90% of the uniformly selected targets have radial velocities consistent with Orion membership. The APOGEE-2 Orion survey will include >1100 bona fide YSOs whose uniform selection function will provide a robust sample for comparative analyses of the stellar populations and properties across all sub-regions of Orion.
120. A polarimetric study of ACOs
ID:
ivo://CDS.VizieR/J/A+A/658/A158
Title:
A polarimetric study of ACOs
Short Name:
J/A+A/658/A158
Date:
22 Feb 2022 15:07:47
Publisher:
CDS
Description:
Asteroids in comet-like orbits (ACOs) consist of asteroids and dormant comets. Due to their similar appearance, it is challenging to distinguish dormant comets from ACOs via general telescopic observations. Surveys for discriminating dormant comets from the ACO population have been conducted via spectroscopy or optical and mid-infrared photometry. However, they have not been conducted through polarimetry. We conducted the first polarimetric research of ACOs. We conducted a linear polarimetric pilot survey for three ACOs: (944) Hidalgo, (3552) Don Quixote, and (331471) 1984 QY1. These objects are unambiguously classified into ACOs in terms of their orbital elements (i.e., the Tisserand parameters with respect to Jupiter TJ significantly less than 3). Three ACOs were observed by the 1.6-m Pirka Telescope from UT 2016 May 25 to UT 2019 July 22 (13 nights). We found that two ACOs, Don Quixote and Hidalgo, have polarimetric properties similar to comet nuclei and D-type asteroids (optical analogs of comet nuclei. However, 1984 QY1 exhibited a polarimetric property consistent with S-type asteroids. We conducted a backward orbital integration to determine the origin of 1984 QY1 and found that this object was transported from the main belt into the current comet-like orbit via the 3:1 mean motion resonance with Jupiter. We conclude that the origins of ACOs can be more reliably identified by adding polarimetric data to the color and spectral information. This study would be valuable for investigating how the ice-bearing small bodies distribute in the inner solar system.