Shamakhy Astrophysical Observatory named after Nasraddin Tusi

ABSTRACT GRANDMA (Global Rapid Advanced Network Devoted to the Multi-messenger Addicts) is a network of 25 telescopes of different sizes, including both photometric and spectroscopic facilities. The network aims to coordinate follow-up observations of gravitational-wave (GW) candidate alerts, especially those with large localization uncertainties, to reduce the delay between the initial detection and the optical confirmation. In this paper, we detail GRANDMA’s observational performance during Advanced LIGO/Advanced Virgo Observing Run 3 (O3), focusing on the second part of O3; this includes summary statistics pertaining to coverage and possible astrophysical origin of the candidates. To do so, we quantify our observation efficiency in terms of delay between GW candidate trigger time, observations, and the total coverage. Using an optimized and robust coordination system, GRANDMA followed-up about 90 per cent of the GW candidate alerts, that is 49 out of 56 candidates. This led to coverage of over 9000 deg2 during O3. The delay between the GW candidate trigger and the first observation was below 1.5 h for 50 per cent of the alerts. We did not detect any electromagnetic counterparts to the GW candidates during O3, likely due to the very large localization areas (on average thousands of degrees squares) and relatively large distance of the candidates (above 200 Mpc for 60 per cent of binary neutron star, BNS candidates). We derive constraints on potential kilonova properties for two potential BNS coalescences (GW190425 and S200213t), assuming that the events’ locations were imaged.

ABSTRACT We present the Global Rapid Advanced Network Devoted to the Multi-messenger Addicts (GRANDMA). The network consists of 21 telescopes with both photometric and spectroscopic facilities. They are connected together thanks to a dedicated infrastructure. The network aims at coordinating the observations of large sky position estimates of transient events to enhance their follow-up and reduce the delay between the initial detection and optical confirmation. The GRANDMA programme mainly focuses on follow-up of gravitational-wave alerts to find and characterize the electromagnetic counterpart during the third observational campaign of the Advanced LIGO and Advanced Virgo detectors. But it allows for follow-up of any transient alerts involving neutrinos or gamma-ray bursts, even those with poor spatial localization. We present the different facilities, tools, and methods we developed for this network and show its efficiency using observations of LIGO/Virgo S190425z, a binary neutron star merger candidate. We furthermore report on all GRANDMA follow-up observations performed during the first six months of the LIGO–Virgo observational campaign, and we derive constraints on the kilonova properties assuming that the events’ locations were imaged by our telescopes.

Abstract Object GRB 221009A is the brightest gamma-ray burst (GRB) detected in more than 50 yr of study. In this paper, we present observations in the X-ray and optical domains obtained by the GRANDMA Collaboration and the Insight Collaboration. We study the optical afterglow with empirical fitting using the GRANDMA+HXMT-LE data sets augmented with data from the literature up to 60 days. We then model numerically using a Bayesian approach, and we find that the GRB afterglow, extinguished by a large dust column, is most likely behind a combination of a large Milky Way dust column and moderate low-metallicity dust in the host galaxy. Using the GRANDMA+HXMT-LE+XRT data set, we find that the simplest model, where the observed afterglow is produced by synchrotron radiation at the forward external shock during the deceleration of a top-hat relativistic jet by a uniform medium, fits the multiwavelength observations only moderately well, with a tension between the observed temporal and spectral evolution. This tension is confirmed when using the augmented data set. We find that the consideration of a jet structure (Gaussian or power law), the inclusion of synchrotron self-Compton emission, or the presence of an underlying supernova do not improve the predictions. Placed in the global context of GRB optical afterglows, we find that the afterglow of GRB 221009A is luminous but not extraordinarily so, highlighting that some aspects of this GRB do not deviate from the global known sample despite its extreme energetics and the peculiar afterglow evolution.

BACKGROUND: Despite substantial progress in modern preventive and clinical cardiology, acute myocardial infarction (AMI) remains a central acute cardiac event. The aim of this study was to check the basic daily environmental-physical conditions accompanying the occurrence of AMIs in a specific geographic area: Baku, Azerbaijan. MATERIAL/METHODS: AMIs registered in the Baku area by 21 first-aid stations (n=4919) during 2003-2005 were compared with daily geomagnetic activity (GMA) levels (I(0)-IV(0)) and cosmic ray activity (CRA), described by neutron (imp/min) and solar activity. The same comparison was made for pre-admission fatal AMIs (n=440). The cosmophysical data came from space science centers in the USA, Russia, and Finland. RESULTS: AMI morbidity followed a daily distribution according to GMA, mostly on quiet (I(0)) GMA days. A monthly comparison showed inverse relationships with solar activity and GMA and correlation with CRA. The daily clinical parameters of AMI correlated with CRA. Despite the daily rise in AMI mortality on days with the highest GMA, the days with the lowest GMA and higher CRA were predominant for AMI occurrence and pre-admission mortality. One of the possible predisposing factors can be life-threatening arrhythmia. CONCLUSIONS: The monthly number of AMIs was inversely related to monthly solar activity and correlated with CRA-neutron activity. Pre-admission AMI mortality was inversely linked with GMA. Daily AMI pre-admission mortality rose with concomitant GMA; low-GMA and higher-neutron-activity AMIs occurred much more frequently and were more strongly related to the number of fatal pre-admission AMIs. The clinical course of AMI was linked with CRA level.

This paper addresses the question of why metal-deficient barium stars are not yellow symbiotic stars (YSyS). Samples of (suspected) metal-deficient barium (mdBa) stars and YSyS have been collected from the literature, and their properties reviewed. It appears in particular that the barium nature of the suspected mdBa stars needs to be ascertained by detailed abundance analyses. Abundances are therefore derived for two of them, HD 139409 and HD 148897, which reveal that HD 148897 should not be considered a barium star. HD 139409 is a mild barium star, with overabundances observed only for elements belonging to the first s-process peak (Y and Zr). It is only moderately metal-poor ([Fe/H] = -0.4). The evidence for binarity among mdBa stars is then reviewed, using three different methods: (i) radial-velocity variations (from CORAVEL observations), (ii) Hipparcos astrometric data, and (iii) a method based on the comparison between the Hipparcos and Tycho-2 proper motions. An orbit is obtained for HIP 55852, whereas evidence for the (so far unknown) binary nature of HIP 34795, HIP 76605, HIP 97874 and HIP 107478 is presented. No conclusion regarding the binary nature of HIP 11595, HIP 25161 could be reached. Two stars with no evidence for binarity whatsoever (HIP 58596 and BD +3°2688) are candidates low-metallicity thermally-pulsing asymptotic giant branch stars, as inferred from their large luminosities. The reason why mdBa stars are not YSyS is suggested to lie in their different orbital period distributions: mdBa stars have on average longer orbital periods than YSyS, and hence their companion accretes matter at a lower rate, for a given mass loss rate of the giant star. The definite validation of this explanation should nevertheless await the determination of the orbital periods for the many mdBa stars still lacking periods, in order to make the comparison more significant.

Optical and near-infrared photometry, optical spectroscopy, and soft X-ray and UV monitoring of the changing-look active galactic nucleus NGC 2617 show that it continues to have the appearance of a type-1 Seyfert galaxy. An optical light curve for 2010–2016 indicates that the change of type probably occurred between 2010 October and 2012 February and was not related to the brightening in 2013. In 2016, NGC 2617 brightened again to a level of activity close to that in 2013 April. We find variations in all passbands and in both the intensities and profiles of the broad Balmer lines. A new displaced emission peak has appeared in Hβ. X-ray variations are well correlated with UV–optical variability and possibly lead by ∼2–3 d. The K band lags the J band by about 21.5 ± 2.5 d and lags the combined B + J filters by ∼25 d. J lags B by about 3 d. This could be because J-band variability arises from the outer part of the accretion disc, while K-band variability comes from thermal re-emission by dust. We propose that spectral-type changes are a result of increasing central luminosity causing sublimation of the innermost dust in the hollow bi-conical outflow. We briefly discuss various other possible reasons that might explain the dramatic changes in NGC 2617.

The stability problem for small magnetohydrodynamic (MHD) perturbations in an optically thin, perfectly conducting uniform plasma with a cosmic abundance of elements is solved in the linear approximation. The electron heat conduction along the magnetic field and the proton heat conduction across the field are taken into account. We have shown for the first time that the entropy waves can grow exponentially, while the magnetosonic waves are damped in a wide range of physical conditions closest to the conditions in stellar coronae with the proper allowance for radiative losses. Slow magnetosonic waves are damped particularly rapidly. For the solar corona, the calculated damping decrement of slow magnetosonic waves agrees well with the averaged one in 11 quasi-periodic events observed from the TRACE satellite in extreme ultraviolet radiation. Other possible astrophysical applications of the results obtained are briefly discussed.

This paper addresses the question of why metal-deficient barium stars are not yellow symbiotic stars (YSyS). Samples of (suspected) metal-deficient barium (mdBa) stars and YSyS have been collected from the literature, and their properties reviewed. It appears in particular that the barium nature of the suspected mdBa stars needs to be ascertained by detailed abundance analyses. Abundances are therefore derived for two of them, HD 139409 and HD 148897, which reveal that HD 148897 should not be considered a barium star. HD 139409 is a mild barium star, with overabundances observed only for elements belonging to the first s-process peak (Y and Zr). The evidence for binarity among mdBa stars is then reviewed, using three different methods: (i) radial-velocity variations (from CORAVEL observations), (ii) Hipparcos astrometric data, and (iii) a method based on the comparison between the Hipparcos and Tycho-2 proper motions. A first-time orbit is obtained for HIP 55852, whereas evidence for the (so far unknown) binary nature of HIP 34795, HIP 76605, HIP 97874 and HIP 107478 is presented. Two stars with no evidence for binarity whatsoever (HIP 58596 and BD +3 2688) are candidates low-metallicity thermally-pulsing asymptotic giant branch stars, as inferred from their large luminosities. The reason why mdBa stars are not YSyS is suggested to lie in their different orbital period distributions: mdBa stars have on average longer orbital periods than YSyS, and hence their companion accretes matter at a lower rate, for a given mass loss rate of the giant star. The definite validation of this explanation should nevertheless await the determination of the orbital periods for the many mdBa stars still lacking periods, in order to make the comparison more significant.

Aims. We study wave instability in an collisionless, rarefied hot plasma (e.g. solar wind or corona). We consider the anisotropy produced by the magnetic field, when the thermal gas pressures across and along the field become unequal.

We report the abundance determination in the atmosphere of the bright halo star HD 221170. The spectra were taken with the Terskol Observatory's 2.0-m telescope with a resolution 45 000 and signal-to-noise ratio up to 250 in the wavelength region 3638–10 275 Å. The adopted atmospheric parameters correspond to an effective temperature = 4475 K, a surface gravity = 1.0, a microturbulent velocity = 1.7 , and a macroturbulent velocity = 4 . The abundances of 43 chemical elements were determined with the method of spectrum synthesis. The large overabundances (by 1 dex relative to iron) of elements with Z > 38 are shown to follow the same pattern as the solar r-abundances. The present HD 221170 analysis confirms the non-universality of the r-process, or more exactly the observation that the astrophysical sites hosting the r-process do not always lead to a unique relative abundance distribution for the bulk Ba to Hg elements, the Pb-peak elements, and the actinides.

We present chemical abundances in the photosphere of δ Scuti (δ Sct) – a prototype of the class of pulsating variables – determined from the analysis of a spectrum obtained by using the 2-m telescope at the Peak Terskol Observatory and a high-resolution spectrometer with R= 52 000, a signal-to-noise ratio 250 and from International Ultraviolet Explorer spectra. The abundance pattern of δ Sct consists of 49 chemical elements. The abundances of 19 elements have not been investigated previously. The abundances of Pr and Nd obtained from the lines of the second and third spectra are equal. The abundances of heavy elements indicate the overabundances with respect to the solar system values up to 1 dex. The abundance pattern of δ Sct is similar to the abundance patterns of Am–Fm or δ Del type stars. A splitting of the cores of all clean lines is observed for the spectra of δ Sct and HD 57749. This can signify evidence of non-radial pulsations in these stars.

The links of many medical-biological events with high levels of geomagnetic activity (GMA) are widely discussed. In recent years, several medical phenomena were described in inverse distribution by time with GMA. Also a concurrent to GMA and solar activity force-cosmic ray activity (CRA) and closely related high energy neutron and proton fluxes are studied as a forces dominating at low GMA and solar activity in relation to considered medical events. The aim of this study was to explore the distribution of some important medical events on days with “Zero” GMA levels, accompanied by high CRA (neutron activity). Medical event data of the Grand Baku region (more than 3 mln inhabitants), Azerbaijan, with daily distribution on the time 1 Dec. 2002-31 Dec. 2007 was compared to daily GMA Kp indices in general (Kp > 0, 1837 days) and 34 days daily GMA indices Kp = 0. Daily CRA data was also compared using neutron monitoring data from two stations. Daily averaged data and their standard deviations on the mentioned GMA levels were compared and statistical significance was established. Results revealed a significant rise in the number of emergencies (n = 1,567,576) and total deaths number (n = 46,360) at the days of “Zero” GMA level. These days were accompanied by significant rise of CRA (neutron activity). For Sudden Cardiac Deaths (SCD, n = 1615) and cerebral stroke (CVA, n =10,054) the increase achieved strong trend to significance level. Acute Myocardial Infarction occurrence (morbidity) and trauma were also absolutely more registered at days with “Zero” GMA level, despite the small number of such days. The average Infection numbers show an inverse relationship with absolutely high registry at the “Zero” GMA level days. Study linking environmental physical activity levels and the human medical data shows that geomagnetic field variations accompanied by the increased level of cosmic ray activity, can have either direct or indirect adverse effects on human health and physiology, even when the magnitude of the geomagnetic field disturbance is extremely small or even is equal to zero. On days of “Zero” daily Kp indices describing Geomagnetic Activity, accompanied by high Cosmic Ray Activity (neutron activity), more medical emergencies and total death number (daily) occurred. Sudden Cardiac Deaths and Cerebral Stroke numbers show a strong trend to significant rise. Absolute increase of number of Acute Myocardial Infarction and less Infections, not achieving statistical significance, was also observed. These results are additional data for considering Cosmic Ray Activity (neutron activity) as an additional factor involved in time distribution of human medical events.

Abstract Wave properties and instabilities in a magnetized, anisotropic, collisionless, rarefied hot plasma in fluid approx‐imation are studied, using the 16‐moments set of the transport equations obtained from the Vlasov equations. These equations differ from the CGL‐MHD fluid model (single fluid equations by Chew, Goldberger, and Low [5,9]) by including two anisotropic heat flux evolution equations, where the fluxes invalidate the double polytropic CGL laws. We derived the general dispersion relation for linear compressible wave modes. Besides the classic incompressible fire hose modes there appear four types of compressible wave modes: two fast and slow mirror modes – strongly modified compared to the CGL model – and two thermal modes. In the presence of initial heat fluxes along the magnetic field the wave properties become different for the waves running forward and backward with respect to the magnetic field. The well known discrepancies between the results of the CGL‐MHD fluid model and the kinetic theory are now removed: i) The mirror slow mode instability criterion is now the same as that in the kinetic theory. ii) Similarly, in kinetic studies there appear two kinds of fire hose instabilities ‐ incompressible and compressible ones. These two instabilities can arise for the same plasma parameters, and the instability of the new compressible oblique fire hose modes can become dominant. The compressible fire hose instability is the result of the resonance coupling of three retrograde modes ‐ two thermal modes and a fast mirror mode. The results can be applied to the theory of solar and stellar coronal and wind models (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Abstract Recently discovered long-term oscillations of the solar background magnetic field associated with double dynamo waves generated in inner and outer layers of the Sun indicate that the solar activity is heading in the next three decades (2019–2055) to a Modern grand minimum similar to Maunder one. On the other hand, a reconstruction of solar total irradiance suggests that since the Maunder minimum there is an increase in the cycle-averaged total solar irradiance (TSI) by a value of about 1–1.5 Wm −2 closely correlated with an increase of the baseline (average) terrestrial temperature. In order to understand these two opposite trends, we calculated the double dynamo summary curve of magnetic field variations backward one hundred thousand years allowing us to confirm strong oscillations of solar activity in regular (11 year) and recently reported grand (350–400 year) solar cycles caused by actions of the double solar dynamo. In addition, oscillations of the baseline (zero-line) of magnetic field with a period of 1950 ± 95 years (a super-grand cycle) are discovered by applying a running averaging filter to suppress large-scale oscillations of 11 year cycles. Latest minimum of the baseline oscillations is found to coincide with the grand solar minimum (the Maunder minimum) occurred before the current super-grand cycle start. Since then the baseline magnitude became slowly increasing towards its maximum at 2600 to be followed by its decrease and minimum at ~3700. These oscillations of the baseline solar magnetic field are found associated with a long-term solar inertial motion about the barycenter of the solar system and closely linked to an increase of solar irradiance and terrestrial temperature in the past two centuries. This trend is anticipated to continue in the next six centuries that can lead to a further natural increase of the terrestrial temperature by more than 2.5 °C by 2600.

We report the results of Cyg X-1 spectral monitoring for 2002–2004. A comparison of observed and non-local thermal equilibrium model profiles for H I, He I and Mg II is given, taking into account the tidal distortion of the Cyg X-1 optical component and its illumination by X-ray emission from the secondary component. We set limits on the main characteristics of the optical component, T eff=30 400±500K and log g=3.31±0.07, and on the overabundances of He and Mg, [He]/[H]=0.43±0.06 dex and [Mg]/[H]=0.75±0.15 dex. The Doppler images were reconstructed by an improved Doppler tomography method on the basis of nine He II (λ=4686 Å) profiles from 2003 (the ‘soft’ X-ray state) and six profiles from 2004 (the ‘hard’ X-ray state). This allowed us to set limits on the black-hole-to-supergiant mass ratio (1/4)≤slant M X/M O≤slant (1/3).

We present the historical light curve of NGC 4151 for 1906–2016. The light curve (Oknyanskij and Lyuty, 2007) is primarily based on our published photoelectric data (1968–2007, about 1040 nightly mean measurements (Oknyanskij and Lyuty, 2007)) and photographic estimates (mostlyOdessaandMoscowplates taken in 1906 – 1982 (Oknyanskij, 1978, 1983), about 350 measurements). Additionally, we include all data obtained prior to 1968 (de Vaucouleurs and de Vaucouleurs, 1968; Barnes 1968; Sandage, 1967; Wisniewski and Kleinmann, 1968; Fitch et al., 1967) in total, 19 photoelectric observations from 1958–1967, were reduced by us to the same diaphragm aperture as that used in our measurements) as well as photographic data (Pacholczyk et al., 1983) (Harvard and Steward observatories' patrol plates taken in 1910–1968, about 210 measurements). The light curve includes our old and new photometrical data obtained during last years at SAI, ShAO and Weihai Observatory as well as other published data (Roberts and Rumstey, 2012; Schnülle et al., 2015). All these data were reduced to an uniform photometric system.Applying Fourier (CLEAN algorithm) we have found periodic component ~16 years in the 110 years light curve. 40 years ago about the same "period" was firstly reviled fromOdessa's photometrical data (Oknyanskij, 1977; 1978). This “period” seen in the light curve was then found independently in the spectral variability and interpreted as a case of the supermassive binary black hole (Bon et al., 2012). We interpret these circles as some accretion dynamic time.

We present optical photometric observations of SN 2018aoq from 2 to 100 days after explosion, and 7 spectra at epochs from 11 to 71 days. The light curves and spectra are typical for SNe II-P. As previously reported, SN 2018aoq appears to be of intermediate brightness between subluminous and normal SNe II-P. SN 2018aoq was discovered in Seyfert galaxy NGC 4151, for which the distance is uncertain. We utilised the Expanding Photosphere Method using three sets of filter combinations and velocities derived from the absorption minima of FeII lines and obtained a distance of 20.0 +-1.6 Mpc. The Standard Candle Method applied to SN 2018aoq yields a distance of 16.6 +-1.1 Mpc. Both values are consistent with the distance measurements for NGC 4151 based on geometric method.

ABSTRACT GRB 230812B is a bright and relatively nearby (z = 0.36) long gamma-ray burst (GRB) that has generated significant interest in the community and has thus been observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and submillimetre bands from the GRANDMA (Global Rapid Advanced Network for Multimessenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) of the GRB and compare with other analyses of this event. We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v ∼ 17 × 103 km s−1. We analyse the photometric data first using empirical fits of the flux and then with full Bayesian inference. We again strongly establish the presence of a supernova in the data, with a maximum (pseudo-)bolometric luminosity of 5.75 × 1042 erg s−1, at $15.76^{+0.81}_{-1.21}$ d (in the observer frame) after the trigger, with a half-max time width of 22.0 d. We compare these values with those of SN1998bw, SN2006aj, and SN2013dx. Our best-fitting model favours a very low density environment ($\log _{10}({n_{\rm ISM}/{\rm cm}^{-3}}) = -2.38^{+1.45}_{-1.60}$) and small values for the jet’s core angle $\theta _{\rm core} = 1.54^{+1.02}_{-0.81} \ \rm {deg}$ and viewing angle $\theta _{\rm obs} = 0.76^{+1.29}_{-0.76} \ \rm {deg}$. GRB 230812B is thus one of the best observed afterglows with a distinctive supernova bump.

The results of six years of spectroscopic studies of the Herbig Be star IL Cep (HD216629) are reported. Various spectral parameters of the Hα and Hβ emission lines and those of the He I λ 5876 Å absorption feature are found for the first time to have exhibited slow variations in 2006–2011 and to have reached their extrema in 2009–2010. The Na I D1 and D2 lines reproduce, in a weaker form, the Hα radialvelocity variations. It is suggested that the variations found in the spectrum of the star may be due to the presence of additional bodies in the system.

We investigated a shear instability of the Kelvin-Helmholtz (KH) type in a plasma with temperature anisotropy under the magnetohydodynamics (MHD) approximation. To solve the problem, a system of 16-moment MHD transport equations are used in a collisionless bi-Maxwellian plasma, including the various components of the heat fluxes along the magnetic field. We consider supersonic flows of two semi-infinite anisotropic and homogeneous plasma layers with different physical parameters and velocities. For the general case, i.e., when the interface between these two flows is a transition layer with a finite thickness, we derived a general linear differential equation framework for determining the eigenmodes in the system. Furthermore, we considered thoroughly the limiting case of a zero thickness transition zone (contact discontinuity). The analysis enabled applying appropriate boundary conditions to derive the dispersion equation for interface waves. The obtained equation analyzes in detail for the case when heat fluxes are absent along the discontinuity in the background state. It is shown that the shear flow excites the KH instability and “couples” the various branches of the free-plasma oscillations to each other. It is found that the region of mode interaction is determined by the resonance regions when the longitudinal phase velocities of the waves match. In the resonance flows with an average speed, the KH instability occurs. The growth rates of the KH instability are calculated as a function of the parameters, including the degree of plasma anisotropy. It is found that in most cases the KH instability is dominant in the considered configuration. The obtained results are applied to the plasma conditions in the bimodal solar wind in the vicinity of the contact discontinuity between different flow patterns (fast and slow wind).