- ID:
- ivo://CDS.VizieR/J/AJ/117/102
- Title:
- Photometry + Spectroscopy in HDF + Flanking Fields
- Short Name:
- J/AJ/117/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an HK' wide-field survey encompassing the Hubble Deep Field and its flanking fields. Our wide-field survey provides uniform coverage of a 61.8arcmin^2^ area to a depth equivalent to K=20.1 at 5{sigma}. We have also imaged the Hubble Deep Field in HK', providing uniform coverage of a 7.8arcmin^2^ area to a depth equivalent to K=21.2 at 5{sigma}. Using these data in combination with new deep University of Hawaii 8K V- and I-imaging obtained on the Canada-France-Hawaii Telescope, we find only a small population of objects with colors redder than an equivalent I-K=4mag, the color expected for an evolved elliptical galaxy at z>1. We infer that only a fraction of the local field elliptical galaxy population with M_K_<-23.4 could have formed in single bursts at high redshift. The HK' observations of the HDF and its flanking fields were made with the University of Hawaii 2.2m telescope (1996-02-06 to 1996-02-08 for the HDF, and 1997-04-17 to 1997-04-22 for the wider area) and the 3.6m Canada-France-Hawaii Telescope (CFHT, 1996-04-05 to 1996-04-08 for the HDF). The deep V- and I-band observations were made with the CFHT (1997-04-03 to 1997-04-08), and B-band observations with the Keck Low Resolution Imaging Spectrograph in a strip across the center of the HK wide-field image.
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- ID:
- ivo://CDS.VizieR/J/AJ/161/221
- Title:
- Photometry & spectroscopy of 4 binaries stars
- Short Name:
- J/AJ/161/221
- Date:
- 16 Mar 2022 11:53:19
- Publisher:
- CDS
- Description:
- We present the photometric and spectroscopic analysis of four W-UMa binaries J015829.5+260333 (hereinafter as J0158), J030505.1+293443 (hereinafter as J0305), J102211.7+310022 (hereinafter as J1022), and KW-Psc. The VRcIc band photometric observations are carried out with the 1.3m Devasthal Fast Optical Telescope (DFOT). For low-resolution spectroscopy, we used the 2m Himalayan Chandra Telescope (HCT) as well as the archival data from the 4m LAMOST survey. The systems J0158 and J0305 show a period increase rate of 5.26({+/-}1.72)x10^-7^days/yr and 1.78({+/-}1.52)x10^-6^days/yr, respectively. The period of J1022 is found to be decreasing with a rate of 4.22({+/-}1.67)x10^-6^days/yr. The period analysis of KW-Psc displays no change in its period. The PHOEBE package is used for the light-curve modeling and basic parameters are evaluated with the help of the GAIA parallax. The asymmetry of light curves is explained with the assumption of cool spots at specific positions on one of the components of the system. On the basis of temperatures, mass ratios, fill-out factors, and periods, the system J1022 is identified as a W-subtype system while the others show some mixed properties. To probe the chromospheric activities in these W-UMa binaries, their spectra are compared with the known inactive stars' spectra. The comparison shows emission in H{alpha}, H{beta}, and CaII. To understand the evolutionary status of these systems, the components are plotted in mass-radius and mass-luminosity planes with other well characterized binary systems. The secondary components of all the systems are away from ZAMS, which indicates that the secondary is more evolved than the primary component.
- ID:
- ivo://CDS.VizieR/J/A+A/639/A23
- Title:
- Photometry & spectroscopy of EE Cep: 2014-15
- Short Name:
- J/A+A/639/A23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- EE Cep is one of few eclipsing binary systems with a dark, dusty disk around an invisible object similar to epsilon Aur. The system is characterized by grey and asymmetric eclipses every 5.6yr, with a significant variation in their photometric depth, ranging from ~0.5mag to ~2.0mag. The main aim of the observational campaign of the EE Cep eclipse in 2014 was to test the model of disk precession (Galan et al. 2012). We expected that this eclipse would be one of the deepest with a depth of ~2m.mag. We collected multicolor observations from almost 30 instruments located in Europe and North America. This photometric data covers 243 nights during and around the eclipse. We also analyse the low- and high- resolution spectra from several instruments. The eclipse was shallow with a depth of 0m.71 in V-band. The multicolor photometry illustrates small color changes during the eclipse with a total amplitude of order ~+0.15mag in B-I color index. The linear ephemeris for this system is updated by including new times of minima, measured from the three most recent eclipses at epochs E=9, 10 and 11. New spectroscopic observations were acquired, covering orbital phases around the eclipse, which were not observed in the past and increased the data sample, filling some gaps and giving a better insight into the evolution of the H{alpha} and NaI spectral line profiles during the primary eclipse. The eclipse of EE Cep in 2014 was shallower than expected 0.71mag instead of ~2.0mag. This means that our model of disk precession needs revision.
- ID:
- ivo://CDS.VizieR/J/A+A/327/145
- Title:
- Photopolarimetric activity of RR Tauri
- Short Name:
- J/A+A/327/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of coordinated Crimea-Dodaira simultaneous multi-bands photometric and polarimetric observations of the classical Herbig Ae/Be star RR Tau which cover fully the observed interval of its brightness changes are presented. Within the observed interval of its light variations the linear polarization of RR Tau anti-correlates with its brightness changes.
- ID:
- ivo://CDS.VizieR/J/AZh/77/420
- Title:
- Photopolarimetric activity of SV Cep
- Short Name:
- J/AZh/77/420
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of the eleven-years (1987-98) photopolarimetric patrol observations of Herbig Ae star SV Cep are presented. Only one deep brightness minimum of star were observed during this time interval. The decrease of the SV Cep brightness during this minimum was accompanied by increase of its linear polarization. The similar behaviour of linear polarization with the brightness changes was found earlier in other young stars with the non-periodic Algol-type minima. The most probable interpretation of this phenomenon is based on the model in which the source of intrinsic linear polarization is the scattered radiation of circumstellar disk-like dust envelope (probably the proto-planetary disk). The deposition of this source increases during the brightness minima when the direct (non-polarized) stellar radiation are absorbed in the CS dust clouds intersected the line-of-sight.
- ID:
- ivo://CDS.VizieR/J/ApJ/823/58
- Title:
- Photo-reverberation mapping of 27 YSOs in LDN1688
- Short Name:
- J/ApJ/823/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Theoretical models and spectroscopic observations of newborn stars suggest that protoplanetary disks have an inner "wall" at a distance set by the disk interaction with the star. Around T Tauri stars, the size of this disk hole is expected to be on a 0.1au scale that is unresolved by current adaptive optics imaging, though some model-dependent constraints have been obtained by near-infrared interferometry. Here we report the first measurement of the inner disk wall around a solar-mass young stellar object, YLW 16B in the {rho} Ophiuchi star-forming region, by detecting the light-travel time of the variable radiation from the stellar surface to the disk. Consistent time lags were detected on two nights, when the time series in H (1.6{mu}m) and K (2.2{mu}m) bands were synchronized while the 4.5{mu}m emission lagged by 74.5+/-3.2s. Considering the nearly edge-on geometry of the disk, the inner rim should be 0.084au from the protostar on average, with an error of order 0.01au. This size is likely larger than the range of magnetospheric truncations and consistent with an optically and geometrically thick disk front at the dust sublimation radius at ~1500K. The widths of the cross-correlation functions between the data in different wavebands place possible new constraints on the geometry of the disk.
- ID:
- ivo://CDS.VizieR/J/ApJ/700/L73
- Title:
- Photospheric fluxes at 24 and 70{mu}m
- Short Name:
- J/ApJ/700/L73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dust in debris disks is generated by collisions among planetesimals. The existence of these planetesimals is a consequence of the planet-formation process, but the relationship between debris disks and planets has not been clearly established. Here we analyze Spitzer/MIPS 24 and 70um data for 150 planet-bearing stars, and compare the incidence of debris disks around these stars with a sample of 118 stars around which planets have been searched for, but not found. Together they comprise the largest sample ever assembled to deal with this question. The use of survival analysis techniques allows us to account for the large number of non-detections at 70um. We discovered 10 new debris disks around stars with planets and one around a star without known planets. We found that the incidence of debris disks is marginally higher among stars with planets, than among those without, and that the brightness of the average debris disk is not significantly different in the two samples. We conclude that the presence of a planet that has been detected via current radial velocity techniques is not a good predictor for the presence of a debris disk detected at infrared wavelengths.
- ID:
- ivo://CDS.VizieR/J/A+A/497/497
- Title:
- Physical parameters from JHK flux
- Short Name:
- J/A+A/497/497
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The effective temperature scale of FGK stars, especially at the lowest metallicities remains a major problem in the chemical abundance analysis of metal-poor stars. We present a new implementation of the infrared flux method (IRFM) using the 2MASS catalogue.
- ID:
- ivo://CDS.VizieR/J/A+A/531/A141
- Title:
- Physical parameters of PMS in open clusters
- Short Name:
- J/A+A/531/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our aims are twofold: To determine the physical parameters of PMS members in young open clusters (YOCs), and to check and compare the performances of different model isochrones. We compare UBVRI photometric observations of eleven YOCs to theoretical isochrones in the photometric diagrams. The comparison simultaneously provides membership assignments for MS and PMS stars and estimates for the masses, ages, and spatial distribution of the candidate members. The relations found between the different cluster parameters show that the procedure applied to assign cluster membership, and to measure physical parameters for the selected members, is well founded.
- ID:
- ivo://CDS.VizieR/J/AJ/159/17
- Title:
- Physical properties of SFRs in NGC 3395/NGC 3396
- Short Name:
- J/AJ/159/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report long-slit spectroscopy of the early major merger galaxies NGC 3395/NGC 3396. The spectra are consistent with those for star-forming galaxies, but there is some indication of LINER-like active galactic nucleus activity in the center of NGC 3396. The total star formation rate in the regions observed is 2.83 M_{sun}_/yr, consistent with estimates for the entire galaxies. The highest abundances are in the centers of the galaxies, with the abundances decreasing with distance. There is a correlation between high abundance and high ionization parameter, both of which can be attributed to the presence of massive stars. Modeling with SB 99 indicates the star-forming regions are younger than 10 Myr. There are 1000-2000 WNL stars in the system, along with several thousand O stars, consistent with the ages of the star-forming regions. The highest electron densities are found in young regions with high star formation rates. The electron temperatures are higher than results for non-interacting galaxies, which is probably due to shock waves produced by the galaxy-galaxy interaction, the outflow of gas from massive stars, and/or collisions between gas clouds in the galaxies. There is star formation in the bridge of material between the galaxies. These regions are among the youngest in the system and have low abundances, suggesting the gas was pulled from the outer parts of the galaxies. X-ray point sources, probably high-mass X-ray binaries, are associated with several star-forming regions.
