- ID:
- ivo://CDS.VizieR/J/A+A/422/925
- Title:
- Profile variability in lines of NGC 5548
- Short Name:
- J/A+A/422/925
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Between 1996 and 2002, we have carried out a spectral monitoring program for the Seyfert galaxy NGC 5548 with the 6m and 1m telescopes of SAO (Russia) and with the 2.1m telescope of Guillermo Haro Observatory (GHO) at Cananea, Mexico. High quality spectra with S/N>50 in the continuum near H{alpha} and H{beta} were obtained, covering the spectral range ~(4000-7500){AA} with a (4.5 to 15){AA}-resolution. We found that both the flux in the lines and the continuum gradually decreased, reaching minimum values during May-June 2002. In the minimum state, the wings of H{beta} and H{alpha} became extremely weak, corresponding to a Sy1.8 type, not to a Sy1, as observed previously when the nucleus was brighter. The line profiles were decomposed into variable and constant components. The variable broad component is well correlated with the continuum variation. It consists of a double peaked structure with radial velocities ~+/-1000 km/s relative to the narrow component. A constant component, whose presence is independent of the continuum flux variations, shows only narrow emission lines. The mean, rms, and the averaged over years, observed and difference line profiles of H{beta} and H{alpha} reveal the same double peaked structure. The relative intensity of these peaks changes with time. During 1996, the red peak was the brightest, while in 1998-2002, the blue peak became the brighter one. Their radial velocities vary in the ~(500-1200) km/s range. In 2000-2002 a distinct third peak appeared in the red wing of H{alpha} and H{beta} line profiles. The radial velocity of this feature decreased between 2000 and 2002: from the observed profiles, from ~+(2500-2600) km/s to ~+2000 km/s and is clearly seen on the difference profiles. The fluxes of the various parts of the line profiles are well correlated with each other and also with the continuum flux. The blue and red parts of the line profiles at the same radial velocities vary in an almost identical manner. Shape changes of the different parts of the broad line are not correlated with continuum variations and, apparently, are not related to reverberation effects. Changes of the integral Balmer decrement are, on average, anticorrelated with the continuum flux variations. This is probably due to an increasing role of collisional excitation as the ionizing flux decreases. The behaviour of the Balmer decrement of the various parts of the line profiles was different in 1996-2000 as compared with the 2001 behaviour. Our results favour the formation of the broad Balmer lines in a turbulent accretion disc with large and moving "optically thick" inhomogeneities, capable of reprocessing the central source continuum.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/3766
- Title:
- Project VeSElkA: HD stars atomic-line analysis
- Short Name:
- J/MNRAS/453/3766
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A portion of main-sequence stars, called chemically peculiar (CP) stars, show important abundance anomalies mainly due to atomic diffusion of the species within these stars. Certain CP stars have hydrodynamically stable atmospheres where atomic diffusion may dominate and lead to vertical abundance stratification there. Recently, Project VeSElkA (a word meaning rainbow in Ukrainian and standing for "Vertical Stratification of Element Abundances") was initiated with the goal to detect vertical stratification of chemical abundances in selected CP stars using high-resolution spectra with large signal-to-noise ratios. The first extensive and detailed series of results from atomic-line analysis is presented here for four stars of Project VeSElkA: HD 71030, HD 95608, HD 116235 and HD 186568. These stars were recently observed with ESPaDOnS at Canada-France-Hawaii Telescope. Strong evidence of iron stratification in the atmospheres of HD 95608 and HD 116235 was found. Chromium also shows a steep abundance gradient in the upper atmospheres of these two stars. No evidence of stratification is found for HD 71030 and HD 186568.
- ID:
- ivo://CDS.VizieR/J/A+A/615/A176
- Title:
- Propargylamine accurate rest frequencies
- Short Name:
- J/A+A/615/A176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To date, several complex organic molecules have been detected in the interstellar medium, and they have been suggested as precursors of biologically important species. Propargylamine (HC{triple}C-CH_2_-NH_2_) is structurally similar to a number of other organic molecules which have already been identified by radioastronomy, making it a good candidate for astrophysical detection. This work provides accurate rest frequencies of propargylamine, from the centimeter-wave to the submillimeter-wave region, useful to facilitate the detection of this molecule in the interstellar medium. An extensive laboratory study of the rotational spectrum of propargylamine has been performed using a pulsed-jet Fourier Transform Microwave (FTMW) spectrometer (7-19GHz frequency range) and a frequency modulation microwave spectrometer (75-560GHz). Several hundred rotational transitions of propargylamine were recorded in the ground and three lowest excited vibrational states. The experiments were supported by high-level ab initio computations, mainly employed to characterize the vibrational state structure and to predict spectroscopic parameters unknown prior to this study. The measured transition frequencies yielded accurate rotational constants and the complete sets of quartic and sextic centrifugal distortion constants for propargylamine in its vibrational ground state. ^14^N-nuclear quadrupole coupling constants were also determined. Rotational and quartic centrifugal distortion constants were also obtained for the low-lying excited states v_13_=1(A'), v_20_=1(A"), and v_21_=1(A"). The a-type Coriolis resonance which couples the v_13_=1 and v_21_=1 levels was analyzed. The determined spectroscopic constants allowed for the compilation of a dataset of highly accurate rest frequencies for astrophysical purposes in the millimeter and submillimeter regions with 1{sigma} uncertainties that are smaller than 0.050MHz, corresponding to 0.03km/s at 500GHz in radial equivalent velocity.
- ID:
- ivo://CDS.VizieR/J/AJ/129/2119
- Title:
- Properties for 165 dwarf galaxies
- Short Name:
- J/AJ/129/2119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive inner dark matter halo density profiles for a sample of 165 low-mass galaxies using rotation curves obtained from high-quality, long-slit optical spectra assuming minimal disks and spherical symmetry.
- ID:
- ivo://CDS.VizieR/J/AJ/143/83
- Title:
- Properties of a sample of Seyfert 1 galaxies
- Short Name:
- J/AJ/143/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a statistical study of a large, homogeneously analyzed sample of narrow-line Seyfert 1 (NLS1) galaxies, accompanied by a comparison sample of broad-line Seyfert 1 (BLS1) galaxies. Optical emission-line and continuum properties are subjected to correlation analyses, in order to identify the main drivers of the correlation space of active galactic nuclei (AGNs), and of NLS1 galaxies in particular. For the first time, we have established the density of the narrow-line region as a key parameter in Eigenvector 1 space, as important as the Eddington ratio L/L_Edd_. This is important because it links the properties of the central engine with the properties of the host galaxy, i.e., the interstellar medium (ISM). We also confirm previously found correlations involving the line width of H{beta} and the strength of the Fe II and [O III]{lambda}5007 emission lines, and we confirm the important role played by L/L_Edd_ in driving the properties of NLS1 galaxies. A spatial correlation analysis shows that large-scale environments of the BLS1 and NLS1 galaxies of our sample are similar. If mergers are rare in our sample, accretion-driven winds, on the one hand, or bar-driven inflows, on the other hand, may account for the strong dependence of Eigenvector 1 on ISM density.
- ID:
- ivo://CDS.VizieR/J/ApJ/896/24
- Title:
- Properties of atomic lines in 51 Oph UV spectra
- Short Name:
- J/ApJ/896/24
- Date:
- 07 Mar 2022 13:24:57
- Publisher:
- CDS
- Description:
- We measured 304 absorption features in the ultraviolet and visible spectra of the star 51 Oph, which is known to have a debris disk with a high inclination. We analyzed the relative populations of atoms in excited fine-structure and metastable levels that are maintained by optical pumping and collisional excitation by electrons, and we found that most of the gas is situated at about 6 au from the star, has an electron volume density 10^5^<n(e)<3x10^6^cm^-3^, and a temperature T=8000K. Our interpretations reveal that the gas is partly ionized, has a column density of neutral hydrogen equal to 10^21^cm^-2^, and has a composition similar to that of a mildly depleted interstellar medium or that of Jupiter-family comets. Compared to results for disks around some other stars, such as {beta} Pic and 49 Cet, we find surprisingly little neutral carbon. No molecular features were detected, which indicates that our line of sight misses the molecule-rich central plane of the disk. The tilt of the disk is also validated by our being able to detect resonant scattering of the starlight by oxygen atoms.
- ID:
- ivo://CDS.VizieR/J/ApJ/897/48
- Title:
- Properties of Galactic Be Supergiants. VI.
- Short Name:
- J/ApJ/897/48
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We report the results of long-term spectroscopic monitoring of the A-type supergiant with the B[e] phenomenon 3Pup=HD62623. We confirm earlier findings that it is a binary system. The orbital parameters were derived using cross-correlation of the spectra in a range of 4460-4632{AA}, which contains over 30 absorption lines. The orbit was found to be circular with a period of 137.4{+/-}0.1days, radial velocity semiamplitude K1=5.0{+/-}0.8km/s, systemic radial velocity {gamma}=26.4{+/-}2.0km/s, and mass function f(m)=(1.81_-0.76_^+0.97^)x10^-3^M{sun}. The object may have evolved from a pair with initial masses of ~6.0M{odot} and ~3.6M{sun} with an initial orbital period of ~5days. Based on the fundamental parameters of the A-supergiant (luminosity log L/L{sun}=4.1{+/-}0.1 and effective temperature Teff=8500{+/-}500K) and evolutionary tracks of mass-transferring binaries, we found current masses of the gainer M2=8.8{+/-}0.5M{sun} and donor M1=0.75{+/-}0.25M{sun}. We also modeled the object's IR-excess and derived a dust mass of ~5x10^-5^M{sun} in the optically thin dusty disk. The orbital parameters and properties of the H{alpha} line profile suggest that the circumstellar gaseous disk is predominantly circumbinary. The relatively low mass of the gainer led us to a suggestion that 3 Pup should be excluded from the B[e] supergiant group and moved to the FSCMa group. Overall these results further support our original suggestion that FSCMa objects are binary systems, where an earlier mass transfer caused formation of the circumstellar envelope.
- ID:
- ivo://CDS.VizieR/J/ApJS/122/355
- Title:
- Properties of low z QSO absorption systems
- Short Name:
- J/ApJS/122/355
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (Partial): We examine the clustering properties of low-redshift Ly{alpha} and heavy-element QSO absorption line systems seen in the spectra of 13 QSOs at the Galactic poles. This is the densest sample of ~1 degree separated QSOs observed spectroscopically with the Hubble Space Telescope to date. At the median redshift of the Ly{alpha} sample (z{=~}0.7), the QSO lines of sight are separated on transverse scales from about 15 to 200h^-1^Mpc (q_0_=0.5, H=100h.km/s/Mpc), allowing the three-dimensional clustering of the absorbers to be examined on those scales. The Galactic poles are also regions where relatively deep and wide-field galaxy redshift surveys have taken place, so the distributions of galaxies and Ly{alpha} systems can be compared within the same volume of space. There are 545 total absorption lines detected in the complete sample from 13 QSOs. We identify 307 Ly{alpha} systems, of which 18 contain heavy-element lines. We confirm the relatively slow redshift number density evolution for Ly systems at z{<=}1. There are also five likely C IV doublets in our sample, for which the Ly{alpha} line is not accessible.
- ID:
- ivo://CDS.VizieR/J/AJ/156/213
- Title:
- Properties of N2K stars & new gas giant companions
- Short Name:
- J/AJ/156/213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The N2K planet search program was designed to exploit the planet-metallicity correlation by searching for gas giant planets orbiting metal-rich stars. Here, we present the radial velocity measurements for 378 N2K target stars that were observed with the HIRES spectrograph at Keck Observatory between 2004 and 2017. With this data set, we announce the discovery of six new gas giant exoplanets: a double-planet system orbiting HD 148164 (Msini of 1.23 and 5.16 M_JUP_) and single planet detections around HD 55696 (Msini=3.87 M_JUP_), HD 98736 (Msini=2.33 M_JUP_), HD 203473 (Msini=7.8 M_JUP_), and HD 211810 (Msini=0.67 M_JUP_). These gas giant companions have orbital semimajor axes between 1.0 and 6.2 au and eccentricities ranging from 0.13 to 0.71. We also report evidence for three gravitationally bound companions with Msini between 20 and 30 M_JUP_, placing them in the mass range of brown dwarfs, around HD 148284, HD 214823, and HD 217850, and four low-mass stellar companions orbiting HD 3404, HD 24505, HD 98630, and HD 103459. In addition, we present updated orbital parameters for 42 previously announced planets. We also report a nondetection of the putative companion HD 73256 b. Finally, we highlight the most promising candidates for direct imaging and astrometric detection, and we find that many hot Jupiters from our sample could be detectable by state-of-the-art telescopes such as Gaia.
- ID:
- ivo://CDS.VizieR/J/A+A/368/1006
- Title:
- Properties of OH/IR stars with IRAS LRS spectra
- Short Name:
- J/A+A/368/1006
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This table contains the selected from the literature sample of 1065 OH maser sources with IRAS identification and LRS spectra. The most important physical quantities of these sources are assembled and the list of related references together with the abbreviations used is attached.
