- ID:
- ivo://CDS.VizieR/J/ApJS/253/20
- Title:
- SEAMBHs XII. Reberberation mapping for 15 PG QSOs
- Short Name:
- J/ApJS/253/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we present the first results of the long-term high-cadence spectroscopic monitoring of 15 PG quasars with relatively strong FeII emission, as a part of a broader reverberation mapping campaign performed using the Calar Alto Observatory's 2.2m telescope. The V-band, 5100{AA} continuum, and H{beta} broad emission line light curves are measured for a set of quasars for periods ranging from dozens to more than a hundred epochs between 2017 May and 2020 July. Accurate time lags between the variations of the H{beta} broad-line fluxes and the optical continuum strength are obtained for all 15 quasars, ranging from 17.0_-3.2_^+2.5^ to 95.9_-23.9_^+7.1^ days in the rest frame. The virial masses of the central supermassive black holes are derived for all 15 quasars, ranging between 0.50_-0.19_^+0.18^ and 19.17_-2.73_^+2.98^ in units of 10^7^M_{sun}_. For 11 of the objects in our sample, this is the first reverberation analysis to be published. Of the rest, two objects have been the subject of previous reverberation studies, but we determine time lags for these that are only half as long as those found in the earlier investigations, which had only been able to sample much more sparsely. The remaining two objects have previously been monitored with high sampling rates. Our results here are consistent with the earlier findings, in the sense that the time lag and the line width vary inversely, consistent with virialization.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/896/1
- Title:
- SEAMBHs. XI. Mrk 142 X-ray to optical light curves
- Short Name:
- J/ApJ/896/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed an intensive accretion disk reverberation mapping campaign on the high accretion rate active galactic nucleus Mrk142 in early 2019. Mrk 142 was monitored with the Neil Gehrels Swift Observatory for four months in X-rays and six different UV/optical filters. Ground-based photometric monitoring was obtained from the Las Cumbres Observatory, the Liverpool Telescope, and the Dan Zowada Memorial Observatory in ugriz filters, as well as from the Yunnan Astronomical Observatory in V. Mrk 142 was highly variable throughout, displaying correlated variability across all wavelengths. We measure significant time lags between the different wavelength lightcurves. In the UV and optical, we find that the wavelength-dependent lags, {tau}({lambda}), generally follow the relation {tau}({lambda}){propto}{lambda}^4/3^, as expected for the T{propto}R^-3/4^ profile of a steady-state, optically thick, geometrically thin accretion disk, though they can also be fit by {tau}({lambda}){propto}{lambda}^2^, as expected for a slim disk. The exceptions are the u and U bands, where an excess lag is observed, as has been observed in other active galactic nuclei and attributed to continuum emission arising in the broad-line region. Furthermore, we perform a flux-flux analysis to separate the constant and variable components of the spectral energy distribution, finding that the flux dependence of the variable component is consistent with the f{nu}{propto}{nu}^1/3^ spectrum expected for a geometrically thin accretion disk. Moreover, the X-ray to UV lag is significantly offset from an extrapolation of the UV/optical trend, with the X-rays showing a poorer correlation with the UV than the UV does with the optical. The magnitude of the UV/optical lags is consistent with a highly super-Eddington accretion rate.
- ID:
- ivo://CDS.VizieR/J/ApJ/877/23
- Title:
- SEAMBHs. X. Reverberation mapping campaign compilation
- Short Name:
- J/ApJ/877/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compiled a sample of 73 active galactic nuclei (AGNs) with reverberation mapping (RM) observations from RM campaigns, including our ongoing campaign of monitoring super-Eddington accreting massive black holes (BHs). This sample covers a large range of BH mass (M_{bullet}_=10^6^-9^M_{sun}_), dimensionless accretion rates (dM/dt=10^-2.7^-10^2.7^), and 5100{AA} luminosity (L_5100_=10^42-46^erg/s), allowing us to systematically study the AGN variability and their relations with BH mass, accretion rates, and optical luminosity. We employed the damped random walk (DRW) model to delineate the optical variability of continuum at 5100{AA} and obtained damped variability timescale ({tau}_d_) and amplitude ({sigma}_d_) using a Markov Chain Monte Carlo method. We also estimated the traditional variability amplitudes (F_var_), which provide a model-independent measure and therefore are used to test the DRW results. We found that AGN variability characteristics are generally correlated with (M_{bullet}_, dM/dt, L_5100_). These correlations are smooth from sub-Eddington to super-Eddington accretion AGNs, probably implying that the AGN variability may be caused by the same physical mechanism.
- ID:
- ivo://CDS.VizieR/J/A+A/460/695
- Title:
- Search for Associations Containing Young stars
- Short Name:
- J/A+A/460/695
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results from a high-resolution optical spectroscopic survey aimed to search for nearby young associations and young stars among optical counterparts of ROSAT All-Sky Survey (<IX/10> and <IX/29>, X-ray sources in the Southern Hemisphere. We selected 1953 late-type (B-V>=0.6), potentially young, optical counterparts out of a total of 9574 1RXS sources for follow-up observations. At least one high-resolution spectrum was obtained for each of 1511 targets. This paper is the first in a series presenting the results of the SACY survey. Here we describe our sample and our observations. We describe a convergence method in the (UVW) velocity space to find associations. As an example, we discuss the validity of this method in the framework of the Beta Pic Association.
- ID:
- ivo://CDS.VizieR/J/A+A/385/488
- Title:
- Search for duplicity in periodic Be stars
- Short Name:
- J/A+A/385/488
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Four Be stars, HR 1960, HR 2968, HR 3237 and HR 3642, selected according to their periodic variations in Hipparcos and Geneva photometries, have been monitored from 1998 until 2001 with the Coralie spectrograph. HR 1960 and HR 3237 are two new spectroscopic binaries, HR 3642 is a new lambda Eri star, and HR 2968 is stable.
- ID:
- ivo://CDS.VizieR/J/ApJS/250/29
- Title:
- Search for nearby Earth analogs. III. RV sets
- Short Name:
- J/ApJS/250/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Earth-sized planets in the habitable zones of M dwarfs are good candidates for the study of habitability and detection of biosignatures. To search for these planets, we analyze all available radial velocity data and apply four signal detection criteria to select the optimal candidates. We find 10 strong candidates satisfying these criteria and three weak candidates showing inconsistency over time due to data samplings. We also confirm three previous planet candidates and improve their orbital solutions through combined analyses of updated data sets. Among the strong planet candidates, HIP38594b is a temperate super-Earth with a mass of 8.2+/-1.7M_{Earth}_ and an orbital period of 60.7+/-0.1 days, orbiting around an early-type M dwarf. Early-type M dwarfs are less active and thus are better hosts for habitable planets than mid-type and late-type M dwarfs. Moreover, we report the detection of five two-planet systems, including two systems made up of a warm or cold Neptune and a cold Jupiter, consistent with a positive correlation between these two types of planets. We also detect three temperate Neptunes, four cold Neptunes, and four cold Jupiters, contributing to a rarely explored planet population. Due to their proximity to the Sun, these planets on wide orbits are appropriate targets for direct imaging by future facilities such as the Habitable Exoplanet Observatory and the Extremely Large Telescope.
- ID:
- ivo://CDS.VizieR/J/A+A/650/A205
- Title:
- Search for transiting planets around sdBs
- Short Name:
- J/A+A/650/A205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hot subdwarfs experienced strong mass loss on the red giant branch (RGB) and are now hot and small He-burning objects. These stars constitute excellent opportunities for addressing the question of the evolution of exoplanetary systems directly after the RGB phase of evolution. In this project we aim to perform a transit survey in all available light curves of hot subdwarfs from space-based telescopes (Kepler, K2, TESS, and CHEOPS) with our custom-made pipeline SHERLOCK in order to determine the occurrence rate of planets around these stars as a function of orbital period and planetary radius. We also aim to determine whether planets that were previously engulfed in the envelope of their red giant host star can survive, even partially, as a planetary remnant. For this first paper, we performed injection-and-recovery tests of synthetic transits for a selection of representative Kepler, K2, and TESS light curves to determine which transiting bodies in terms of object radius and orbital period we will be able to detect with our tools. We also provide estimates for CHEOPS data, which we analyzed with the pycheops package. Transiting objects with a radius <~1.0R_{Earth}_ can be detected in most of the Kepler, K2, and CHEOPS targets for the shortest orbital periods (1d and shorter), reaching values as low as ~0.3R_{Earth}_ in the best cases. Sub-Earth-sized bodies are only reached for the brightest TESS targets and for those that were observed in a significant number of sectors. We also give a series of representative results for larger planets at greater distances, which strongly depend on the target magnitude and on the length and quality of the data. The TESS sample will provide the most important statistics for the global aim of measuring the planet occurrence rate around hot subdwarfs. The Kepler, K2, and CHEOPS data will allow us to search for planetary remnants, that is, very close and small (possibly disintegrating) objects.
- ID:
- ivo://CDS.VizieR/J/ApJS/241/6
- Title:
- Searching for super-fast rotators using PS1
- Short Name:
- J/ApJS/241/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A class of asteroids, called large super-fast rotators (large SFRs), have rotation periods shorter than 2hr and diameters larger than ~0.3km. They pose challenges to the usual interior rubble-pile structure unless a relatively high bulk density is assumed. So far, only six large SFRs have been found. Therefore, we present a survey of asteroid rotation periods using the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) 1 telescope during 2016 October 26-31 to search for more large SFRs and to study their properties. A total of 876 reliable rotation periods are measured, among which seven are large SFRs, thereby increasing the inventory of known large SFRs. These seven newly discovered large SFRs have diverse colors and locations in the main asteroid belt, suggesting that the taxonomic tendency and the location preference in the inner main belt of the six previously known large SFRs could be a bias due to various observational limits. Interestingly, five out of the seven newly discovered large SFRs are mid main-belt asteroids (MBAs). Considering the rare discovery rates of large SFR in the previously similar surveys and the survey condition in this work, the chance of detecting a large SFR in the inner main belt seems to be relatively low. This probably suggests that the inner main belt harbors fewer large SFRs than the mid main belt. From our survey, we also found a drop in the number appearing at f>5rev/day on the spin-rate distribution for the outer MBAs of D<3km, which was reported for the inner and mid main belt by Chang et al. (2015, J/ApJS/219/27 ; 2016ApJ...816...71C).
- ID:
- ivo://CDS.VizieR/J/AJ/162/125
- Title:
- Searching transiting planets around halo stars. I.
- Short Name:
- J/AJ/162/125
- Date:
- 21 Mar 2022 00:52:16
- Publisher:
- CDS
- Description:
- By measuring the elemental abundances of a star, we can gain insight into the composition of its initial gas cloud-the formation site of the star and its planets. Planet formation requires metals, the availability of which is determined by the elemental abundance. In the case where metals are extremely deficient, planet formation can be stifled. To investigate such a scenario requires a large sample of metal-poor stars and a search for planets therein. This paper focuses on the selection and validation of a halo star sample. We select ~17000 metal-poor halo stars based on their Galactic kinematics, and confirm their low metallicities ([Fe/H]<-0.5), using spectroscopy from the literature. Furthermore, we perform high-resolution spectroscopic observations using LBT/PEPSI and conduct detailed metallicity ([Fe/H]) analyses on a sample of 13 previously-known halo stars that also have hot kinematics. We can use the halo star sample presented here to measure the frequency of planets and to test planet formation in extremely metal-poor environments. The result of the planet search and its implications will be presented and discussed in a companion paper by Boley et al.
- ID:
- ivo://CDS.VizieR/J/AJ/134/1890
- Title:
- Secondary standard stars in u'g'r'i'z'
- Short Name:
- J/AJ/134/1890
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new set of secondary standard stars for the u'g'r'i'z' photometric system that has been established in selected open and globular star clusters. These standards are calibrated to the original standard system defined by Smith et al. with an accuracy of 1% or better, extend as faint as r'~20, and are concentrated in small regions of the sky. As a result, they can serve as viable calibrators of photometry obtained on some of the large-aperture, high-demand telescopes that employ the u'g'r'i'z' filter set.
