- ID:
- ivo://CDS.VizieR/J/MNRAS/453/2022
- Title:
- Double-mode radial-non-radial RR Lyrae stars
- Short Name:
- J/MNRAS/453/2022
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the OGLE-IV photometry of the first overtone and double-mode RR Lyrae stars (RRc/RRd) in the two fields towards the Galactic bulge observed with high cadence. In 27 per cent of RRc stars, we find additional non-radial mode, with characteristic period ratio, P_x_/P_1O_{include.in}(0.6, 0.64). It strongly corroborates the conclusion arising from the analysis of space photometry of RRc stars, that this form of pulsation must be common. In the Petersen diagram the stars form three sequences. In 20 stars, we find two or three close secondary modes simultaneously. The additional modes are clearly non-stationary. Their amplitude and/or phase vary in time. As a result, the patterns observed in the frequency spectra of these stars may be very complex. In some stars, the additional modes split into doublets, triplets or appear as a more complex bands of increased power. Subharmonics of additional modes are detected in 20 per cent of stars. They also display a complex structure. Including our previous study of the OGLE-III Galactic bulge data, we have discovered 260 RRc and 2 RRd stars with the additional non-radial mode, which is the largest sample of these stars so far. The additional mode is also detected in two Blazhko RRc stars, which shows that the modulation and additional non-radial mode are not exclusive.
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Search Results
- ID:
- ivo://CDS.VizieR/J/PASP/126/509
- Title:
- Double-mode RR Lyrae stars in LINEAR
- Short Name:
- J/PASP/126/509
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Double-mode RR Lyr type stars are important for studies of properties of horizontal-branch stars. In particular, two periods coupled with spectral properties give a mass estimate that is independent of evolutionary models. Here, we present 59 new Galactic double-mode RR Lyr stars found in the LINEAR survey data with the fundamental radial mode and the first overtone exited (RRd stars). These stars may be useful for constraining the mass-metallicity relation for field horizontal-branch stars. Also, new RRd stars found in the LMC by EROS-II are verified. We present the updated Petersen diagram and the distribution of the fundamental mode periods. Comments on selected variable stars from LINEAR and LMC EROS-II surveys are also presented, including very rare objects: the third known mode-switching RR Lyr and a Cepheid pulsating simultaneously in three radial modes.
- ID:
- ivo://CDS.VizieR/J/AJ/157/78
- Title:
- Double & multiple star systems from GaiaDR2
- Short Name:
- J/AJ/157/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Binary and multiple stars have long provided an effective empirical method of testing stellar formation and evolution theories. In particular, the existence of wide binary systems (separations >20000 au) is particularly challenging to binary formation models as their physical separations are beyond the typical size of a collapsing cloud core (~5000-10000 au). We mined the recently published Gaia-DR2 catalog (Cat. I/345) to identify bright comoving systems in the five-dimensional space (sky position, parallax, and proper motion). We identified 3741 comoving binary and multiple stellar candidate systems, out of which 575 have compatible radial velocities for all the members of the system. The candidate systems have separations between ~400 and 500000 au. We used the analysis tools of the Virtual Observatory to characterize the comoving system members and to assess their reliability. The comparison with previous comoving systems catalogs obtained from TGAS showed that these catalogs contain a large number of false systems. In addition, we were not able to confirm the ultra-wide binary population presented in these catalogs. The robustness of our methodology is demonstrated by the identification of well known comoving star clusters and by the low contamination rate for comoving binary systems with projected physical separations <50000 au. These last constitute a reliable sample for further studies. The catalog is available online at the Spanish Virtual Observatory portal (http://svo2.cab.inta-csic.es/vocats/v2/comovingGaiaDR2/).
- ID:
- ivo://CDS.VizieR/J/ApJ/753/42
- Title:
- Double-peaked AGN. I. Dual AGN candidates
- Short Name:
- J/ApJ/753/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Merger-remnant galaxies with kiloparsec (kpc) scale separation dual active galactic nuclei (AGNs) should be widespread as a consequence of galaxy mergers and triggered gas accretion onto supermassive black holes, yet very few dual AGNs have been observed. Galaxies with double-peaked narrow AGN emission lines in the Sloan Digital Sky Survey (SDSS) are plausible dual AGN candidates, but their double-peaked profiles could also be the result of gas kinematics or AGN-driven outflows and jets on small or large scales. To help distinguish between these scenarios, we have obtained spatial profiles of the AGN emission via follow-up long-slit spectroscopy of 81 double-peaked narrow-line AGNs in SDSS at 0.03<=z<=0.36 using Lick, Palomar, and MMT Observatories. We find that all 81 systems exhibit double AGN emission components with ~kpc projected spatial separations on the sky (0.2h^-1^_70_kpc<{Delta}x<5.5h^-1^_70_kpc; median {Delta}x=1.1h^-1^_70_kpc), which suggests that they are produced by kiloparsec-scale dual AGNs or kiloparsec-scale outflows, jets, or rotating gaseous disks.
- ID:
- ivo://CDS.VizieR/J/ApJ/832/67
- Title:
- Double-peaked narrow lines in AGN. II. z<0.1
- Short Name:
- J/ApJ/832/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical long-slit observations of the complete sample of 71 Type 2 active galactic nuclei (AGNs) with double-peaked narrow emission lines at z<0.1 in the Sloan Digital Sky Survey. Double-peaked emission lines are produced by a variety of mechanisms including disk rotation, kiloparsec-scale dual AGNs, and narrow-line region (NLR) kinematics (outflows or inflows). We develop a novel kinematic classification technique to determine the nature of these objects using long-slit spectroscopy alone. We determine that 86% of the double-peaked profiles are produced by moderate-luminosity AGN outflows, 6% are produced by rotation, and 8% are ambiguous. While we are unable to directly identify dual AGNs with long-slit data alone, we explore their potential kinematic classifications with this method. We also find a positive correlation between the NLR size and luminosity of the AGN NLRs (R_NLR_{propto}L_[OIII]_^0.21+/-0.05^), indicating a clumpy two-zone ionization model for the NLR.
- ID:
- ivo://CDS.VizieR/J/ApJ/867/66
- Title:
- Double-peaked narrow lines in AGN. IV. Mergers
- Short Name:
- J/ApJ/867/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Double-peaked narrow emission lines in active galactic nucleus (AGN) spectra can be produced by AGN outflows, rotation, or dual AGNs, which are AGN pairs in ongoing galaxy mergers. Consequently, double-peaked narrow AGN emission lines are useful tracers of the coevolution of galaxies and their supermassive black holes, as driven by AGN feedback and AGN fueling. We investigate this concept further with follow-up optical longslit observations of a sample of 95 Sloan Digital Sky Survey (SDSS) galaxies that have double-peaked narrow AGN emission lines. Based on a kinematic analysis of the longslit spectra, we confirm previous work that finds that the majority of double-peaked narrow AGN emission lines are associated with outflows. We also find that eight of the galaxies have companion galaxies with line-of-sight velocity separations <500km/s and physical separations <30kpc. Since we find evidence of AGNs in both galaxies, all eight of these systems are compelling dual AGN candidates. Galaxies with double-peaked narrow AGN emission lines occur in such galaxy mergers at least twice as often as typical active galaxies. Finally, we conclude that at least 3% of SDSS galaxies with double-peaked narrow AGN emission lines are found in galaxy mergers where both galaxies are resolved in SDSS imaging.
- ID:
- ivo://CDS.VizieR/J/ApJ/693/1554
- Title:
- Double QSOs: merger scenarios
- Short Name:
- J/ApJ/693/1554
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the available sample of double quasars, and investigate their physical properties. Our sample comprises 85 pairs, selected from the Sloan Digital Sky Survey (SDSS). We derive physical parameters for the engine and the host, and model the dynamical evolution of the pair. First, we compare different scaling relationships between massive black holes and their hosts (bulge mass, velocity dispersion, and their possible redshift dependences), and discuss their consistency. We then compute dynamical friction timescales for the double quasar systems to investigate their frequency and their agreement with the "merger driven" scenario for quasar triggering.
5078. Double radio sources
- ID:
- ivo://CDS.VizieR/J/ApJ/413/453
- Title:
- Double radio sources
- Short Name:
- J/ApJ/413/453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/MNRAS/259/563
- Title:
- Double star CCD observations
- Short Name:
- J/MNRAS/259/563
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
5080. Double star measurements
- ID:
- ivo://CDS.VizieR/J/A+AS/106/377
- Title:
- Double star measurements
- Short Name:
- J/A+AS/106/377
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 1 gives 1182 measurements of 682 binaries observed with the 74 and 50 cm refractors. Table 2 lists 26 new binaries discovered with the 50 cm refractor.