- ID:
- ivo://CDS.VizieR/J/A+A/454/855
- Title:
- Geneva photometry of W Cru
- Short Name:
- J/A+A/454/855
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Light curves of the long-period Algols are known for their complex (asymmetry in the eclipse, light variations outside the eclipse, changes from cycle-to-cycle), but their interpretation is not possible in the standard model of binary stars. We determined that complex structures present in these active Algol systems could be studied with the eclipse-mapping method that was successfully applied to the new 7-color photometric observations in the Geneva system of W Cru, belonging to the isolated group of these active Algols. Several cycles of this long-period (198.5-days) eclipsing binary were covered by observations. We used a modified Rutten's approach to the eclipse-mapping. The optimization of the system's parameters and the recovery of the disk intensity distribution are performed using a genetic algorithm (GA). The finding of a primary (hot) component is hidden in thick accretion disk confirms previous solutions. The mass of the primary component, M_1_=8.2M_{sun}_, indicates that it is a mid-B type star. The mass-losing component fills its critical lobe, which, for the system's parameters, means it is a G-type supergiant with a mass M_2_=1.6M_{sun}_. The disk is very extended geometrically, and its outer radius is about 80% of the primary's critical lobe. A reconstructed image reveals the rather clumpy and nonuniform brightness distribution of an accretion disk rim in this system that is seen almost edge-on. This clumpiness accounts for light curve distortions and asymmetries, as well as for secular changes.
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- ID:
- ivo://CDS.VizieR/J/A+A/449/305
- Title:
- Geneva photometry time series of HD 203664
- Short Name:
- J/A+A/449/305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We made a seismic study of the young massive beta Cephei star HD 203664 with the goal of constraining its interior structure. Our study is based on a time series of 328 new Geneva 7-colour photometric data of the star spread over 496.8 days. The data confirm the frequency of the dominant mode of the star, which we refined to f_1_=6.02885c/d. The mode has a large amplitude of 37mmag in V and is unambiguously identified as a dipole mode (l=2) from its amplitude ratios and non-adiabatic computations. Besides f_1_, we discovered two additional new frequencies in the star with amplitudes above 4{sigma}: f_2_=6.82902c/d and f_3_=4.81543c/d, or one of their daily aliases. The amplitudes of these two modes are only between 3 and 4mmag, which explains why they were not detected before. Their amplitude ratios are too uncertain for mode identification. We show that the observed oscillation spectrum of HD 203664 is compatible with standard stellar models but that we have insufficient information for asteroseismic inferences. Among the large-amplitude beta Cephei stars, HD 203664 stands out as the only one rotating at a significant fraction of its critical rotation velocity (~40%).
- ID:
- ivo://CDS.VizieR/VI/102
- Title:
- Geneva stellar evolution tracks and isochrones
- Short Name:
- VI/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This database was created from an updated version of the empirically and semi-empirically calibrated BaSeL library of synthetic stellar spectra of Lejeune et al. (1997, Cat. <J/A+AS/125/229>, 1998, Cat. <J/A+AS/130/65>) and Westera et al. (1999, ASP Conference Series 192, 203-206) to calculate synthetic photometry in the (UBV)_J_(RI)_C_ JHKLL'M, HST-WFPC2, Geneva, and Washington systems for the entire set of non-rotating Geneva stellar evolution models covering masses from 0.4-0.8 to 120-150M_{sun}_ and metallicities Z=0.0004 (1/50Z_{sun}_) to 0.1 (5Z_{sun}_). The results are provided in a database which includes all individual stellar tracks and the corresponding isochrones covering ages from 10^3^yr to 16-20Gyr in time steps of {Delta}logt=0.05dex. The database also includes a new grid of stellar tracks of very metal-poor stars (Z=0.0004) from 0.8-150M_{sun}_ calculated with the Geneva stellar evolution code. The complete stellar grids are tabulated in the files table1.dat (summary), evol.dat (evolutionary models), and in the files ubv.dat, hst.dat, gen.dat and cmt.dat (synthetic colors in the different photometric systems). These grids are also available as mod* files in subdirectories evol, ubv, hst, gen and cmt. The isochrones for the different photometric systems are summarized in the file table2.dat; the parameters of the isochrones are tabulated in the file iso.dat, the detailed isochrones being available as files iso* in the subdirectories ubv, hst, gen and cmt.
- ID:
- ivo://CDS.VizieR/J/A+A/659/L4
- Title:
- Geometric albedo of HD 209458 b
- Short Name:
- J/A+A/659/L4
- Date:
- 02 Mar 2022 07:55:13
- Publisher:
- CDS
- Description:
- We report the detection of the secondary eclipse of the hot Jupiter HD 209458 b in optical/visible light using the CHEOPS space telescope. Our measurement of 20.4^+3.2^_3.3_ parts per million (ppm) translates into a geometric albedo of Ag=0.096+/-0.016. The previously estimated dayside temperature of about 1500K implies that our geometric albedo measurement consists predominantly of reflected starlight and is largely uncontaminated by thermal emission. This makes the present result one of the most robust measurements of Ag for any exoplanet, critical for understanding the atmosphere. Our calculations of the bandpass-integrated geometric albedo demonstrate that the measured value of Ag is consistent with a cloud-free atmosphere, where starlight is reflected via Rayleigh scattering by hydrogen molecules, with water and sodium abundances consistent with stellar metallicity. We predict that the bandpass-integrated TESS geometric albedo is too faint to detect and that a phase curve of HD 209458 b observed by CHEOPS would have a distinct shape associated with Rayleigh scattering if the atmosphere is indeed cloud-free.
2225. GEOS RR Lyr survey
- ID:
- ivo://CDS.VizieR/J/other/IBVS/5767
- Title:
- GEOS RR Lyr survey
- Short Name:
- J/other/IBVS/576
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here the sixth list of light maxima of RR Lyrae stars from the GEOS RR Lyr Survey, a GEOS program (http://www.upv.es/geos/) (Boninsegna et al., 2002ASPC..259..166B) of automated observations of RR Lyr stars started in January 2004.
- ID:
- ivo://CDS.VizieR/J/ApJ/740/59
- Title:
- 1.4GHz and X-ray sources in 12 clusters of galaxies
- Short Name:
- J/ApJ/740/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Chandra imaging spectroscopy and Very Large Array (VLA) L-band radio maps, we have identified radio sources at P_1.4GHz_>=5x10^23^W/Hz and X-ray point sources (XPSs) at L_0.3-8keV_>=5x10^42^erg/s in L>L* galaxies in 12 high-redshift (0.4<z<1.2) clusters of galaxies. The radio galaxies and XPSs in this cluster sample, chosen to be consistent with Coma Cluster progenitors at these redshifts, are compared to those found at low-z analyzed in Hart et al. (Paper I, 2009ApJ...705..854H). Within a projected radius of 1Mpc of the cluster cores, we find 17 cluster radio galaxies (11 with secure redshifts, including one luminous FR II radio source at z=0.826, and six more with host galaxy colors similar to cluster ellipticals). Within this same projected radius, we identify seven spectroscopically confirmed cluster XPSs, all with cluster red-sequence (CRS) host galaxy colors. Consistent with the results from Martini et al. (2009ApJ...701...66M), we estimate a minimum X-ray active fraction of 1.4%+/-0.8% for cluster red-sequence galaxies in high-z clusters, corresponding to an approximate 10-fold increase from 0.15%+/-0.15% at low-z. Although complete redshift information is lacking for several XPSs in z>0.4 cluster fields, the increased numbers and luminosities of the CRS radio galaxies and XPSs suggest a substantial (9-10-fold) increase in the heat injected into high-redshift clusters by AGNs compared to the present epoch.
- ID:
- ivo://CDS.VizieR/J/ApJ/846/160
- Title:
- 6.7GHz Class II methanol maser survey
- Short Name:
- J/ApJ/846/160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed a systematic 6.7GHz Class II methanol maser survey using the Shanghai Tianma Radio Telescope toward targets selected from the all-sky Wide-Field Infrared Survey Explorer (WISE) point catalog. In this paper, we report the results from the survey of those at high Galactic latitudes, i.e., |b|>2{deg}. Of 1473 selected WISE point sources at high latitude, 17 point positions that were actually associated with 12 sources were detected with maser emission, reflecting the rarity (1%-2%) of methanol masers in the region away from the Galactic plane. Out of the 12 sources, 3 are detected for the first time. The spectral energy distribution at infrared bands shows that these new detected masers occur in the massive star-forming regions. Compared to previous detections, the methanol maser changes significantly in both spectral profiles and flux densities. The infrared WISE images show that almost all of these masers are located in the positions of the bright WISE point sources. Compared to the methanol masers at the Galactic plane, these high-latitude methanol masers provide good tracers for investigating the physics and kinematics around massive young stellar objects, because they are believed to be less affected by the surrounding cluster environment.
- ID:
- ivo://CDS.VizieR/J/ApJS/200/5
- Title:
- 95GHz class I methanol maser survey
- Short Name:
- J/ApJS/200/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a survey with the Purple Mountain Observatory 13.7m radio telescope for class I methanol masers from the 95GHz (8_0_-7_1_A^+^) transition. Two hundred and fourteen target sources were selected by combining information from both the Spitzer GLIMPSE and 1.1mm Bolocam Galactic Plane Survey (BGPS) catalogs. The observed sources satisfy the GLIMPSE mid-IR criteria of [3.6]-[4.5]>1.3, [3.6]-[5.8]>2.5, [3.6]-[8.0]>2.5 and 8.0um mag less than 10; they also have an associated 1.1mm BGPS source. Class I methanol maser emission was detected in 63 sources, corresponding to a detection rate of 29% for this survey. For the majority of detections (43), this is the first identification of class I methanol masers associated with these sources. We show that the intensity of the class I methanol maser emission is not closely related to mid-IR intensity or the colors of the GLIMPSE point sources; however, it is closely correlated with properties (mass and beam-averaged column density) of the BGPS sources. Comparison of measures of star formation activity for the BGPS sources with and without class I methanol masers indicates that the sources with class I methanol masers usually have higher column density and larger flux density than those without them.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/20
- Title:
- 22GHz H_2_O maser survey toward IR sources
- Short Name:
- J/ApJ/769/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a 22GHz H_2_O maser survey toward a new sample of asymptotic giant branch (AGB) and post-AGB star candidates. Most of the objects are selected for the first time based on the AKARI data, which have high flux sensitivity in the mid-infrared ranges. We aim at finding H_2_O maser sources in the transient phase between the AGB and post-AGB stages of evolution, where the envelopes start to develop large deviations from spherical symmetry. The observations were carried out with the Effelsberg 100m radio telescope. Among 204 observed objects, 63 detections (36 new) were obtained. We found four objects that may be "water fountain" sources (IRAS 15193+3132, IRAS 18056-1514, OH 16.3-3.0, and IRAS 18455+0448). They possess an H_2_O maser velocity coverage much smaller than those in other known water fountains. However, the coverage is still larger than that of the 1612MHz OH maser. It implies that there is an outflow with a higher velocity than the envelope expansion velocity (typically <=25km/s), meeting the criterion of the water fountain class. We suggest that these candidates are possibly oxygen-rich late AGB or early post-AGB stars in a stage of evolution immediately after the spherically symmetric AGB mass loss has ceased.
- ID:
- ivo://CDS.VizieR/J/ApJ/831/168
- Title:
- 6GHz JVLA observations of low-z SDSS quasars
- Short Name:
- J/ApJ/831/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss 6GHz JVLA observations covering a volume-limited sample of 178 low-redshift (0.2<z<0.3) optically selected quasi-stellar objects (QSOs). Our 176 radio detections fall into two clear categories: (1) about 20% are radio-loud QSOs (RLQs) with spectral luminosities of L_6_>~10^23.2^W/Hz that are primarily generated in the active galactic nucleus (AGN) responsible for the excess optical luminosity that defines a bona fide QSO; and (2) the remaining 80% that are radio-quiet QSOs (RQQs) that have 10^21^<~L_6_<~10^23.2^W/Hz and radio sizes <~10kpc, and we suggest that the bulk of their radio emission is powered by star formation in their host galaxies. "Radio-silent" QSOs (L_6_<~10^21^W/Hz) are rare, so most RQQ host galaxies form stars faster than the Milky Way; they are not "red and dead" ellipticals. Earlier radio observations did not have the luminosity sensitivity of L_6_<~10^21^W/Hz that is needed to distinguish between such RLQs and RQQs. Strong, generally double-sided radio emission spanning >>10kpc was found to be associated with 13 of the 18 RLQ cores with peak flux densities of S_p_>5mJy/beam (log(L)>~24). The radio luminosity function of optically selected QSOs and the extended radio emission associated with RLQs are both inconsistent with simple "unified" models that invoke relativistic beaming from randomly oriented QSOs to explain the difference between RLQs and RQQs. Some intrinsic property of the AGNs or their host galaxies must also determine whether or not a QSO appears radio-loud.
