- ID:
- ivo://CDS.VizieR/J/ApJS/251/15
- Title:
- LAMOST-Kepler/K2 survey (LK-MRS) first year obs.
- Short Name:
- J/ApJS/251/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Phase II of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST)-Kepler/K2 survey (LK-MRS), initiated in 2018, aims at collecting medium-resolution spectra (R~7500; hereafter MRS) for more than 50000 stars with multiple visits (~60 epochs) over a period of 5yr (2018 September to 2023 June). We selected 20 footprints distributed across the Kepler field and six K2 campaigns, with each plate containing a number of stars ranging from ~2000 to ~3000. During the first year of observations, the LK-MRS has already visited 13 plates 223 times over 40 individual nights, and collected ~280000 and ~369000 high-quality spectra in the blue and red wavelength ranges, respectively. The atmospheric parameters and radial velocities for ~259000 spectra of 21053 targets were successfully calculated by the LAMOST stellar parameter pipeline. The internal uncertainties for the effective temperature, surface gravity, metallicity, and radial velocity are found to be 100K, 0.15dex, 0.09dex, and 1.00km/s, respectively, when derived from a medium-resolution LAMOST spectrum with a signal-to-noise ratio (S/N) in the g band of 10. All of the uncertainties decrease as S/N increases, but they stabilize for S/N>100. We found 14997, 20091, and 1514 stars in common with the targets from the LAMOST low-resolution survey (LRS), Gaia, and the Apache Point Observatory Galactic Evolution Experiment (APOGEE), respectively, corresponding to fractions of ~70%, ~95%, and ~7.2%. In general, the parameters derived from LK-MRS spectra are consistent with those obtained from the LRS and APOGEE spectra, but the scatter increases as the surface gravity decreases when comparing with the measurements from APOGEE. A large discrepancy is found with the Gaia values of the effective temperature. Comparisons of the radial velocities of LK-MRS to Gaia and LK-MRS to APOGEE nearly follow a Gaussian distribution with means of {mu}~1.10 and 0.73km/s, respectively. We expect that the results from the LK-MRS spectra will shed new light on binary stars, asteroseismology, stellar activity, and other research fields.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/716/993
- Title:
- LAMP: reverberation mapping of H and He lines
- Short Name:
- J/ApJ/716/993
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z<0.05) Seyfert 1 galaxies with expected masses in the range ~10^6^-10^7^M_{sun}_ and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad H{beta} emission, which we have previously reported. We present here the light curves for the H{alpha}, H{gamma}, HeII{lambda}4686, and HeI{lambda}5876 emission lines and the time lags for the emission-line responses relative to changes in the continuum flux.
- ID:
- ivo://CDS.VizieR/J/ApJ/842/120
- Title:
- Large spectrosc. survey of Palomar 5 stellar stream
- Short Name:
- J/ApJ/842/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present two spectroscopic surveys of the tidal stellar stream of the Palomar 5 globular cluster undertaken with the VLT/FLAMES and AAT/AAOmega instruments. We use these data in conjunction with photometric data presented in the previous contribution in this series to classify the survey stars in terms of their probability of belonging to the Palomar 5 stellar stream. We find that high-probability candidates are only found in a very narrow spatial interval surrounding the locus of the stream on the sky. PanSTARRS RRLyrae stars in this region of the sky are also distributed in a similar manner. The absence of significant "fanning" of this stellar stream confirms that Palomar 5 does not follow a chaotic orbit. Previous studies have found that Palomar 5 is largely devoid of low-mass stars, and we show that this is true also of the stellar populations along the trailing arm out to 6{deg}. Within this region, which contains 73% of the detected stars, the population is statistically identical to the core, implying that the ejection of the low-mass stars occurred before the formation of the stream. We also present an updated structural model fit to the bound remnant, which yields a total mass of 4297+/-98M_{sun}_ and a tidal radius 0.145+/-0.009kpc. We estimate the mass of the observed system including the stream to be 12200+/-400M_{sun}_, and the initial mass to have been ~47000+/-1500M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A78
- Title:
- LARS VIII. Spatially resolved Halpha kinematics
- Short Name:
- J/A+A/587/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present integral field spectroscopic observations with the Potsdam Multi-Aperture Spectrophotometer of all 14 galaxies in the z~0.1 Lyman Alpha Reference Sample (LARS). We produce 2D line-of-sight velocity maps and velocity dispersion maps from the Balmer {alpha} (H{alpha}) emission in our data cubes. These maps trace the spectral and spatial properties of the LARS galaxies' intrinsic Ly{alpha} radiation field. We show our kinematic maps that are spatially registered onto the Hubble Space Telescope H{alpha} and Lyman{alpha} (Ly{alpha}) images. We can conjecture a causal connection between spatially resolved H{alpha} kinematics and Ly{alpha} photometry for individual galaxies. However, no general trend can be established for the whole sample. Furthermore, we compute the intrinsic velocity dispersion {sigma}_0_, the shearing velocity v_shear_, and the v_shear_/{sigma}_0_ ratio from our kinematic maps. In general LARS galaxies are characterised by high intrinsic velocity dispersions (54km/s median) and low shearing velocities (65km/s median). The v_shear_/{sigma}_0_ values range from 0.5 to 3.2 with an average of 1.5. It is noteworthy that five galaxies of the sample are dispersion-dominated systems with v_shear_/{sigma}_0_<1, and are thus kinematically similar to turbulent star-forming galaxies seen at high redshift. When linking our kinematical statistics to the global LARS Ly{alpha} properties, we find that dispersion-dominated systems show higher Ly{alpha} equivalent widths and higher Ly{alpha} escape fractions than systems with v_shear_/{sigma}_0_>1. Our result indicates that turbulence in actively star-forming systems is causally connected to interstellar medium conditions that favour an escape of Ly{alpha} radiation.
- ID:
- ivo://CDS.VizieR/J/AJ/161/194
- Title:
- LCs and RVs of 5 exoplanets discovered by TESS
- Short Name:
- J/AJ/161/194
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We present the discovery and characterization of five hot and warm Jupiters TOI-628b (TIC281408474; HD288842), TOI-640b (TIC147977348), TOI-1333b (TIC395171208, BD+473521A), TOI-1478b (TIC409794137), and TOI-1601b (TIC139375960)-based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (R_P_=1.01-1.77R_J_) and have masses that range from 0.85 to 6.33M_J_. The host stars of these systems have F and G spectral types (5595<~Teff<~6460K) and are all relatively bright (9.5<V<10.8, 8.2<K<9.3), making them well suited for future detailed characterization efforts. Three of the systems in our sample (TOI-640b, TOI-1333b, and TOI-1601b) orbit subgiant host stars (logg<4.1). TOI-640b is one of only three known hot Jupiters to have a highly inflated radius (R_P_>1.7R_J_, possibly a result of its host star's evolution) and resides on an orbit with a period longer than 5days. TOI-628b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of 6.31_-0.30_^+0.28^M_J_ and a statistically significant, nonzero orbital eccentricity of e=0.074_-0.022_^+0.021^. This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478b (P=10.18days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA's TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/14
- Title:
- LCs & spectra of SDSS J1515+1511 lens system
- Short Name:
- J/ApJ/836/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze new optical observations of the gravitational lens system SDSS J1515+1511. These include a 2.6-year photometric monitoring with the Liverpool Telescope (LT) in the r band, as well as a spectroscopic follow-up with the LT and the Gran Telescopio Canarias (GTC). Our r-band LT light curves cover a quiescent microlensing period of the doubly imaged quasar at z_s_=2.049, which permits us to robustly estimate the time delay between the two images A and B: 211+/-5d (1{sigma} confidence interval; A is leading). Unfortunately, the main lensing galaxy (G1) is so faint and close to the bright quasar that it is not feasible to accurately extract its spectrum through the GTC data. However, assuming the putative redshift z_G1_=0.742, the GTC and LT spectra of the distant quasar are used to discuss the macrolens magnification, and the extinction and microlensing effects in G1. The new constraints on the time delay and macrolens magnification ratio essentially do not change previous findings on the mass scale of G1 and external shear, while the redshift of the lensing mass is found to be consistent with the assumed value of z_G1_. This is clear evidence that G1 is indeed located at z_G1_=0.742. From the GTC data, we also obtain the redshift of two additional objects (the secondary galaxy G2 and a new absorption system) and discuss their possible roles in the lens scenario.
- ID:
- ivo://CDS.VizieR/J/MNRAS/244/408
- Title:
- LDSS Deep Redshift Survey
- Short Name:
- J/MNRAS/244/408
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a multisplit spectrograph, LDSS, we have obtained intermediate dispersion spectroscopy for a new sample of 149 faint objects selected randomly from the magnitude range 21<=bJ<=22.5 in three high-latitude fields.
- ID:
- ivo://CDS.VizieR/J/ApJS/239/27
- Title:
- LEGA-C DR2: galaxies in the COSMOS field
- Short Name:
- J/ApJS/239/27
- Date:
- 01 Mar 2022
- Publisher:
- CDS
- Description:
- We present the second data release of the Large Early Galaxy Astrophysics Census (LEGA-C), an ESO 130-night public spectroscopic survey conducted with VIMOS on the Very Large Telescope. We release 1988 spectra with typical continuum S/N~20{AA}^-1^ of galaxies at 0.6<~z<~1.0, each observed for ~20hr and fully reduced with a custom-built pipeline. We also release a catalog with spectroscopic redshifts, emission-line fluxes, Lick/IDS indices, and observed stellar and gas velocity dispersions that are spatially integrated quantities, including both rotational motions and genuine dispersion. To illustrate the new parameter space in the intermediate-redshift regime probed by LEGA-C, we explore relationships between dynamical and stellar population properties. The star-forming galaxies typically have observed stellar velocity dispersions of ~150km/s and strong H{delta} absorption (H{delta}_A_~5{AA}), while passive galaxies have higher observed stellar velocity dispersions (~200km/s) and weak H{delta} absorption (H{delta}_A_~0{AA}). Strong [OIII]5007/H{beta} ratios tend to occur mostly for galaxies with weak H{delta}_A_ or galaxies with higher observed velocity dispersion. Beyond these broad trends, we find a diversity of possible combinations of rest-frame colors, absorption-line strengths, and emission-line detections, illustrating the utility of spectroscopic measurements to more accurately understand galaxy evolution.
- ID:
- ivo://CDS.VizieR/J/A+AS/146/217
- Title:
- Library of Spectra (0.5 to 2.5um) of Cool Stars
- Short Name:
- J/A+AS/146/217
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present catalogue contains 182 low resolution optical spectra, 145 medium resolution (R~1100) near-IR spectra, and 112 merged optical+near-IR spectra that range from about 510 to 2450 nm. The observed stars are luminous cool objects: the sample includes red giants, red supergiants, oxygen rich and carbon rich long period variables (asymptotic giant branch stars), as well as a few Galactic Bulge and LMC/SMC stars. The optical data were acquired on the so-called 74 inch Telescope at Mount Stromlo Observatory. The near-IR data were acquired with the Cryogenic Array Spectrometer and Imager CASPIR on the 2.3 meter Australian National University Telescope at Siding Spring Observatory. Optical and near-IR data for variable objects have been merged only when both were taken less than 15 days apart; but both spectral ranges are also provided separately. The spectra are corrected for telluric absorption. However, in regions where the transmission of the Earth atmosphere is close to zero the fluxes recovered remain highly uncertain. The flux calibration is based on a series of reference stars, for which a theoretical intrinsic energy distribution was assumed. An absolute flux calibration (to about 10% accuracy) was only achieved in exceptional cases; in the other cases, the absolute fluxes can be off their real values by an order of magnitude due to slit losses (for the programme star and/or the reference star) and to non-photometric wheather. Uncertainties in the relative values of fluxes along each spectrum are described in the paper.
- ID:
- ivo://CDS.VizieR/J/AJ/159/90
- Title:
- Li, C and O abundances of FGK stars
- Short Name:
- J/AJ/159/90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Abundances of lithium, carbon, and oxygen have been derived using spectral synthesis for a sample of 249 bright F, G, and K Northern Hemisphere dwarf stars from the high-resolution spectra acquired with the Vilnius University Echelle Spectrograph (VUES) at the Moletai Astronomical Observatory of Vilnius University. The sample stars have metallicities, effective temperatures, and ages between -0.7-0.4dex, 5000-6900K, 1-12Gyr, accordingly. We confirm a so far unexplained lithium abundance decrease at supersolar metallicities --A(Li) in our sample stars, which drop by 0.7dex in the [Fe/H] range from +0.10 to +0.55dex. Furthermore, we identified stars with similar ages, atmospheric parameters, and rotational velocities, but with significantly different lithium abundances, which suggests that additional specific evolutionary factors should be taken into account while interpreting the stellar lithium content. Nine stars with predominantly supersolar metallicities, i.e., about 12% among 78 stars with C and O abundances determined, have the C/O number ratios larger than 0.65, thus may form carbon-rich rocky planets. Ten planet-hosting stars, available in our sample, do not show a discernible difference from the stars with no planets detected regarding their lithium content.