Optical spectroscopy study of the recent AG Pegasi (AG Peg) outburst observed during the second half of 2015 is presented. Considerable variations of the intensity and the shape of the spectral ...features as well as the changes of the hot component parameters, caused by the outburst, are discussed and certain similarities between the outburst of AG Peg and the outburst of a classical symbiotic stars are shown. It seems that after the end of the symbiotic nova phase, AG Peg became a member of the classical symbiotic stars group.
We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period 1999–2018. Using new and published data, we found that during “disc-rise” the expansion velocity of the ...circumstellar disc is 0.4–0.7 km s−1. Our results suggest that the disc radius in recent decades show evidence of resonant truncation of the disc by resonances 10:1, 3:1, and 2:1, while the maximum disc size is larger than the Roche lobe of the primary and smaller than the closest approach of the neutron star. We find correlation between equivalent width of Hα emission line (Wα) and the X-ray flux, which is visible when 15 Å < Wα ≤ 40 Å. The correlation is probably due to wind Roche lobe overflow.
We report observations of the flickering variability of the symbiotic recurrent nova RS Oph at quiescence in five bands (UBVRI). We find evidence of a correlation between the peak-to-peak flickering ...amplitude (ΔF) and the average flux of the hot component (F
av). The correlation is highly significant, with a correlation coefficient of 0.85 and a p-value of ∼10−20. Combining the data from all wavebands, we find a dependence of the type
$\Delta F \propto F_{{\rm av}}^k$
, with power-law index k = 1.02 ± 0.04 for the UBVRI flickering of RS Oph. Thus, the relationship between the amplitude of variability and the average flux of the hot component is consistent with linearity. The rms amplitude of flickering is on average 8 per cent (±2 per cent) of F
av. The detected correlation is similar to that found in accreting black holes/neutron stars and cataclysmic variables. The possible reasons are briefly discussed. The data are available upon request from the authors.
Context.
St 2-22 is a relatively poorly studied S-type symbiotic system that belongs to a small group of jet-producing systems as a result of disc accretion onto a white dwarf fed by its red giant ...companion.
Aims.
The goal of this paper is to analyse the nature and derive the basic parameters of St 2-22, and to follow the jet evolution.
Methods.
Photometric monitoring for over 16 yr and high-quality spectroscopic data enabled us to shed new light on its nature. The high-resolution SALT spectra and
V
I
c
photometry obtained during and between the last two outbursts have been used to search for periodic changes, to derive spectroscopic orbits of both system components, and to study the outburst and jet evolution.
Results.
We present the orbital and stellar parameters of the system components. The orbital period is
P
orb
= 918 ± 6
d
. The double-line spectroscopic orbits indicate the mass ratio
q
=
M
g
M
h
−1
= 3.50 ± 0.53, and the components masses
M
g
sin
3
i
∼ 2.35
M
⊙
and
M
h
sin
3
i
∼ 0.67
M
⊙
. The orbit shows significant eccentricity,
e
= 0.16 ± 0.07. The orbital inclination is close to 70°. During outbursts, accelerating and decelerating jets are observed with changes in their radial velocity component in a range from ∼1500 up to nearly 1800 km s
−1
. St 2-22 turned out to be a classical symbiotic system very similar to the precursor of the group – Z And.
We compute the virial mass (M) of the central black hole and the luminosity-to-mass (L/M) ratio of ≈300 low-z quasars and luminous type 1 Seyfert nuclei. We analyse the following: (1) whether ...radio-quiet and radio-loud objects show systematic differences in terms of M and L/M; (2) the influence of M and L/M on the shape of the Hβ broad component line profile; and (3) the significance of the so-called ‘blue outliers’, i.e. sources showing a significant blueshift of the O iiiλλ4959,5007 lines with respect to the narrow component of Hβ, which is used as an estimator of the quasar reference frame. We show that M and L/M distributions for radio-quiet and radio-loud sources are probably different for samples matched in luminosity and redshift, in the sense that radio-quiet sources have systematically smaller masses and larger L/M. However, the L/M ratio distributions become indistinguishable if 8.5 < log M < 9.5. Line profile comparisons for median spectra computed over narrow ranges of M and L/M indicate that a Lorentz function provides a better fit for higher L/M sources and a double Gaussian for lower L/M values. A second (redshifted) Gaussian component at low L/M appears as a red asymmetry frequently observed in radio-loud and radio-quiet sources with broader (full width at half-maximum ≳4000 km s−1) Hβ broad component profiles. This component becomes stronger in larger mass and lower L/M sources. No specific influence of radio loudness on the Hβ broad component profile is detected, although equivalent widths of Hβ broad component and especially of O iiiλλ4959,5007 are larger for radio-loud sources. We identify five more ‘blue outlier’ sources. Since these sources are, on average, one magnitude brighter than other active galactic nuclei with similar mass, their resulting Eddington ratio is 2–3 times higher. We hint at evolutionary effects that explain some of these results, and reinforce the ‘eigenvector 1’ correlations.
ABSTRACT
We present spectroscopic observations of the Be/X-ray binary X Per obtained during the period 2017 December–2020 January (MJD 58095–58865). In 2017 December, the H α, H β, and He i 6678 ...emission lines were symmetric with violet-to-red peak ratio V/R ≈ 1. During the first part of the period (2017 December–2018 August), the V/R ratio decreased to 0.5 and the asymmetry developed simultaneously in all three lines. In 2018 September, a third component with velocity ≈250 km s−1 appeared on the red side of the He i line profile. Later, this component emerged in H β, accompanied by the appearance of a red shoulder in H α. Assuming that it is due to an eccentric wave in the circumstellar disc, we find that the eccentric wave appeared first in the innermost part of the disc, it spreads out with outflowing velocity vwave ≈ 1.1 ± 0.2 km s−1, and the eccentricity of the eccentric wave is ewave ≈ 0.29 ± 0.07. A detailed understanding of the origin of such eccentricities would have applications to a wide range of systems from planetary rings to AGNs.
We performed optical photometry and spectral observations of the symbiotic stars 4U1954+319 and ZZ CMi. For 4U1954+319, using high-resolution spectra, we, measure the equivalent widths of diffuse ...interstellar bands (DIBs) and estimate the interstellar reddening E(B-V ) = 0:83?0:09. Using the GAIA distances and our photometry, we find: (1) the absolute V -band magnitude MV =-5:23 ? 0:08 of 4U1954+319 and that the mass donor is a supergiant of luminosity class Ib, and (2) MV = -0:27?0:2 for ZZ CMi and that the mass donor is a giant of luminosity class III.
We report optical spectroscopic observations of the Be/γ-ray binaries LSI+61303, MWC 148 and MWC 656. The peak separation and equivalent widths of prominent emission lines (Hα, Hβ, Hγ, HeI, and FeII) ...are measured. We estimated the circumstellar disc size, compared it with separation between the components, and discussed the disc truncation. We find that in LSI+61°303 the compact object comes into contact with the outer parts of the circumstellar disc at periastron, in MWC 148 the compact object goes deeply into the disc during the periastron passage, and in MWC 656 the black hole is accreting from the outer parts of the circumstellar disc along the entire orbit. The interstellar extinction was estimated using interstellar lines. The rotation of the mass donors appears to be similar to the rotation of the mass donors in Be/X-ray binaries. We suggest that X-ray/optical periodicity ~1 day deserves to be searched for.
We performed high-resolution optical spectroscopy and X-ray observations of the recently identified Mira-type symbiotic star EF Aql. Based on high-resolution optical spectroscopy obtained with SALT, ...we determine the temperature (~55 000 K) and the luminosity (~5.3 L⨀) of the hot component in the system. The heliocentric radial velocities of the emission lines in the spectra reveal possible stratification of the chemical elements. We also estimate the mass-loss rate of the Mira donor star. Our Swift observation did not detect EF Aql in X-rays. The upper limit of the X-ray observations is 10(exp -12) erg cm(exp -2) s(exp -1), which means that EF Aql is consistent with the faintest X-ray systems detected so far. Otherwise, we detected it with the UVOT instrument with an average UVM2 magnitude of 14.05. During the exposure, EF Aql became approximately 0.2 UVM2 magnitudes fainter. The periodogram analysis of the V-band data reveals an improved period of 320.4±0.3 d caused by the pulsations of the Mira-type donor star. The spectra are available upon request from the authors.
We report 138 spectral observations of the Hα emission line of the radio- and γ-ray-emitting Be/X-ray binary LSI+61°303 obtained during the period of September 1998 – January 2013. From measuring ...various Hα parameters, we found that the orbital modulation of the Hα is best visible in the equivalent width ratio EW(B)/EW(R), the equivalent width of the blue hump, and in the radial velocity of the central dip. The periodogram analysis confirmed that the Hα emission is modulated with the orbital and superorbital periods. For the past 20 years the radius of the circumstellar disk is similar to the Roche lobe size at the periastron. It is probably truncated by a 6:1 resonance. The orbital maximum of the equivalent width of Hα emission peaks after the periastron and coincides on average with the X-ray and γ-ray maxima. All the spectra are available upon request from the authors and through the CDS.
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