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1.
The main stages in the creation of the Russian segment of the MASTER network of robotic telescopes is described. This network is designed for studies of the prompt optical emission of gammaray bursts (GRBs; optical emission synchronous with the gamma-ray radiation) and surveys of the sky aimed at discovering uncataloged objects and photometric studies for various programs. The first results obtained by the network, during its construction and immediately after its completion in December 2010, are presented. Eighty-nine alert pointings at GRBs (in most cases, being the first ground telescopes to point at the GRBs) were made from September 2006 through July 2011. The MASTER network holds first place in the world in terms of the total number of first pointings, and currently more than half of first pointings at GRBs by ground telescopes are made by the MASTER network. Photometric light curves of GRB 091020, GRB 091127, GRB 100901A, GRB 100906A, GRB 10925A, GRB 110106A, GRB 110422A, and GRB 110530A are presented. It is especially important that prompt emission was observed for GRB 100901A and GRB 100906A, and thar GRB 091127, GRB 110422A, and GRB 110106A were observed from the first seconds in two polarizations. Very-wide-field cameras carried out synchronous observations of the prompt emission of GRB 081102, GRB 081130B, GRB 090305B, GRB 090320B, GRB 090328, and GRB 090424. Discoveries of Type Ia supernovae are ongoing (among them the brightest supernova in 2009): 2008gy, 2009nr, 2010V, and others. In all, photometry of 387 supernovae has been carried out, 43 of which were either discovered or first observed with MASTER telescopes; more than half of these are Type Ia supernovae. Photometric studies of the open clusters NGC 7129 and NGC 7142 have been conducted, leading to the discovery of 38 variable stars. Sixty-nine optical transients have been discovered. 相似文献
2.
The results of observations with the MASTER-SHOK robotic wide-field optical cameras onboard the Lomonosov Space Observatory carried out in 2016 are presented. In all, the automated transient detection system transmitted 22 181 images of moving objects with signal-to-noise ratios greater than 5 to the Earth. Approximately 84% of these images are identified with well-known artificial Earth satellites (including repeated images of the same satellite) and fragments of such satellites (space debris), according to databases of known satellites. The remaining 16% of the images are relate to uncatalogued objects. This first experience in optical space-based monitoring of near-Earth space demonstrates the high efficiency and great potential of using large-aperture cameras in space, based on the software and technology of the MASTER robotic optical complexes (the Mobile Astronomical System of TElescope- Robots (MASTER) global network of robotic telescopes of Lomonosov Moscow State University). 相似文献
3.
The results of white-light photometry for a uniquely long series of data (13.5 hours of observations, 1124 measurements) for the Near-Earth Asteroid (NEA) 2015 TB145 are presented. These data were obtained with the MASTER-Amur and MASTER-Tavrida wide-field robotic telescopes of the Mobile Astronomical System of Telescope-Robots (MASTER) global network of Lomonosov Moscow State University, located in the Crimea and in Blagoveshchensk. The object moved by more than 120° during the observations. The asteroid passed the point of closest approach to the Earth, i.e., observations were carried during both the asteroid's approach and recession. Thus, due to the geometry of the passage, this series of observations contains information about the asteroid viewed at different angles, and is very suitable for precisely determining the shape of the object. Mathematical modeling of the light curve and astrometric positions (with the Asteroids3D code) was carried out, and the probable shape of the asteroid (conical) and the rotation period of 5.9 hours were obtained, as well as the orientation of the rotation axis in ecliptic coordinates: longitude λ = 53°, latitude β = −20°. The derived period coincides with twice the period of 2.9 hours obtained by other observers published earlier, within the uncertainties. 相似文献
4.
We present the results of observations obtained using the MASTER robotic telescope in 2005–2006, including the earliest observations of the optical emission of the gamma-ray bursts GRB 050824 and GRB 060926. Together with later observations, these data yield the brightness-variation law t ?0.55±0.05 for GRB 050824. An optical flare was detected in GRB 060926—a brightness enhancement that repeated the behavior observed in the X-ray variations. The spectrum of GRB 060926 is found to be F E ～ E ?β , where β = 1.0 ± 0.2. Limits on the optical brightnesses of 26 gamma-ray bursts have been derived, 9 of these for the first time. Data for more than 90% of the accessible sky down to 19 m were taken and reduced in real time during the survey. A database has been composed based on these data. Limits have been placed on the rate of optical flares that are not associated with detected gamma-ray bursts, and on the opening angle for the beams of gamma-ray bursts. Three new supernovae have been discovered: SN 2005bv (type Ia)—the first to be discovered on Russian territory, SN 2005ee—one of the most powerful type II supernovae known, and SN 2006ak (type Ia). We have obtained an image of SN 2006X during the growth stage and a light curve that fully describes the brightness maximum and exponential decay. A new method for searching for optical transients of gamma-ray bursts detected using triangulation from various spacecraft is proposed and tested. 相似文献
5.
We present the results of early observations for 130 error-boxes of gamma-ray bursts performed with the Mobile Astronomical System of TElescope-Robots (MASTER) global network of robotic telescopes from Moscow State University in fully automatic mode (2011–2017). Among them, GRB 130907A, GRB 120811C, GRB 110801A, GRB 120404A, GRB 140129B, GRB140311B, and GRB 160227A are considered in details. Among these 130 gamma-ray bursts, in the first 60 s after the trigger with the Swift, Fermi, INTEGRAL, MAXI, Lomonosov, and Konus-Wind orbital observatories, the MASTER was pointed on 51 gamma-ray bursts, being the leader in terms of the first pointing. Full observation automation and MASTER own real-time image processing software allowed us to obtain unique data on early optical emission that accompanied 44 gamma-ray bursts (GRB 110801A, GRB120106A, GRB 120404A, GRB 120811C, GRB 120907A, GRB 121011A, GRB 130122A, GRB 130907A, GRB 131030A, GRB 131125A, GRB 140103A, GRB 140108A, GRB 140129B, GRB 140206A, GRB 140304A, GRB 140311B, GRB 140512A, GRB 140629A, GRB 140801A, GRB140907A, GRB 140930B, GRB141028A, GRB 141225A, GRB 150210A, GRB 150211A, GRB 150301B, GRB 150323C, GRB 150404A/Fermi trigger 449861706, GRB 150403A, GRB 150413A, GRB 150518A, GRB 150627A, GRB 151021A, GRB 151215A, GRB 160104A, GRB 160117B, GRB 160131A, GRB 160227A, GRB 160425A, GRB 160611A, GRB 160625B, GRB 160804A, GRB 160910A, GRB 161017A, GRB 161117A, GRB 161119A). We obtain light curves for 13 gamma-ray bursts among the above listed ones and compare the data in the optical (MASTER), X-ray (Swift-XRT), and hard X-ray (Swift-BAT) ranges. 相似文献
6.
The results of optical, radio, and gamma-ray observations of the blazar AO 0235+16 are presented, including photometric ( BV RIJHK) and polarimetric ( R)monitoring carried out at St. Petersburg State University and the Central (Pulkovo) Astronomical Observatory in 2007–2015, 43 GHz Very Long Baseline Interferometry radio observations processed at Boston University, and a gamma-ray light curve based on observationswith the Fermi space observatory are presented. Two strong outbursts were detected. The relative spectral energy distributions of the variable components responsible for the outbursts are determined; these follow power laws, but with different spectral indices. The degree of polarization was high in both outbursts; only an average relationship between the brightness and polarization can be found. There was no time lag between the variations in the optical and gamma-ray, suggesting that the sources of the radiation in the optical and gamma-ray are located in the same region of the jet. 相似文献
7.
The results of photometric ( BV RIJHK) and polarimetric ( R)monitoring of the blazar 3C 66A performed at the St. Petersburg State University and the Central AstronomicalObservatory of the Russian Academy of Sciences in 2007–2015, radio observations performed by the Boston University team with the Very Long Baseline Array at 43 GHz, and a gamma-ray light curve based on observations with the Fermi SpaceObservatory are presented. Color variations of the object are studied. Changes in the optical spectral energy distribution are observed at some times, indicating the appearance and disappearance of individual variable sources. A variable source with a degree of polarization of 36% is identified, which is responsible for the polarization variations observed during one episode. The correlations between the variations in the different spectral ranges indicate that the optical and gamma-ray radiation originates near the radio core detected at 43 GHz. The presence of five superluminal components emerging from the core is detected. 相似文献
8.
The detection of pulsed radio emission from the X-ray pulsar AXP 4U 0142+61 with a period of P = 8.68832935(6) s and a period derivative of $
\dot P
$
\dot P
= 18.713(4) × 10 −13 s/s is reported. The observations were carried out on two high-sensitivity radio telescopes of the Pushchino Radio Astronomy
Observatory: the Large Phased Array at 111MHz and the DKR-1000 at 40MHz.Mean pulse profiles are presented; the measured flux
density is S
111 = 30 ± 20 mJy. The estimated distance derived from the dispersion measure, 27 pc/cm 3, is 1.4 kpc, and the integrated radio luminosity is L
R
= 1.5 × 10 27 erg/cm. Comparison with X-ray data shows an appreciable difference in the pulse duration (the radio pulse is about a factor
of 20 more narrow) and strong variations in the flux density. 相似文献
9.
We consider possibilities for presently operating and planned infrared, submillimeter, and millimeter telescopes for observations
of the epoch of reionization in the Universe, i.e., of the sources of ultraviolet radiation that have caused the reionization
(galaxies, quasars, etc.) and the ionized intergalactic medium. Along with direct observations of such sources in the optical
and infrared, we analyze the feasibility of observations of the intergalactic gas, as well as fluctuations of the temperature
and polarization of the cosmic microwave background due to inhomogeneities in the reionization process. 相似文献
10.
We present the results of WBVR observations of the low-mass X-ray binary V1341 Cyg = Cyg X-2. Our observations include a total of 2375 individual measurements
in four bands on 478 nights in 1986–1992. We tied the comparison and check stars used for the binary to the WBVR catalog using their JHK magnitudes. The uncertainty of this procedure was 3% in the B and V bands and 8%–10% for the W and R bands. In quiescence, the amplitude of the periodic component in the binary’s B brightness variations is within 0.265
m
–0.278
m
(0.290
m
–0.320
m
in W); this is due to the ellipsoidal shape of the optical component, which is distorted with gravitational forces from the X-ray
component. Some of the system’s active states (long flares) may be due to instabilities in the accretion disk, and possibly
to instabilities of gas flows and other accretion structures. The binary possesses a low-luminosity accretion disk. The light
curves reveal no indications of an eclipse near the phases of the upper and lower conjunctions in quiescence or in active
states during the observed intervals. We conclude that the optical star in the close binary V1341 Cyg = Cyg X-2 is a red giant
rather than a blue straggler. We studied the longterm variability of the binary during the seven years covered by our observations.
The optical observations presented in this study are compared to X-ray data from the Ginga observatory for the same time intervals. 相似文献
11.
The results of multicolor photometric and polarization observations of the blazar 4C 38.41 (Q 1633+382) performed at St. Petersburg State University, the Pulkovo Astronomical Observatory of the Russian Academy of Sciences, Boston University, and Steward Observatory in 2006–2017 are analyzed. Separate variable sources responsible for the observed activity are distinguished, whose power-lawspectra and high degree of polarization confirm their synchrotron nature. The observed color variability of the object (redder when brighter) can be explained by an increase in the contribution to the total emission of a red component with variable flux and a constant relative spectral energy distribution. A close correlation between the optical and gamma-ray light curves is identified, suggesting the same location of the variable sources responsible for the radiation in these bands. 相似文献
12.
Photometric observations of the radio source S5 0716+714 were obtained in BV RI filters from January 20, 1998 to January 9, 2001 with Zeiss-600 and Zeiss-1000 telescopes of the Special Astrophysical Observatory of the Russian Academy of Sciences. The light curves in all the bands are synchronous, providing evidence for the real variability of the object in timescales, from hundreds of days to 5–10 min. No time shift between events in the adjacent filters was detected. The variability spectrum at frequencies of 0.003–100 d ?1 (3.5 × 10 ?8–1.1 × 10 ?3 Hz) is close to that of a flicker noise. The optical spectral index α ( S ～ v α) varies from ?1.59 at the minimum to ?1.13 at the maximum brightness. Measurements of linear polarization in BV R carried out on April 12–13, 2000 confirmed a high degree of polarization and rapid fluctuations of the polarization in a timescale of 15–30 min, whose amplitude decreases at red wavelengths. All the optical properties of the source, its compactness, the absence of spectral lines, the high degree of polarization, and very rapid fluctuations of the brightness, polarization, and spectral index, suggest a synchrotron origin for optical radiation. It may be that we are observing the radiation from a group of very compact bodies (～10 ?10 arcsec) at various stages of their evolution. 相似文献
13.
The creation of a specialized network of large, wide-angle telescopes for distributed observations of near-Earth space using a Russian–Cuban Observatory is considered. An extremely important goal of routine monitoring of near-Earth and near-Sun space is warding off threats with both natural and technogenic origins. Natural threats are associated with asteroids or comets, and technogenic threats with man-made debris in near-Earth space. A modern network of ground-based optical instruments designed to ward off such threats must: (a) have a global and, if possible, uniform geographic distribution, (b) be suitable for wide-angle, high-accuracy precision survey observations, and (c) be created and operated within a single network-oriented framework. Experience at the Institute of Astronomy on the development of one-meter-class wide-angle telescopes and elements of a super-wide-angle telescope cluster is applied to determine preferences for the composition of each node of such a network. The efficiency of distributed observations in attaining maximally accurate predictions of the motions of potentially dangerous celestial bodies as they approach the Earth and in observations of space debris and man-made satellites is estimated. The first estimates of astroclimatic conditions at the proposed site of the future Russian–Cuban Observatory in the mountains of the Sierra del Rosario Biosphere Reserve are obtained. Special attention is given to the possible use of the network to carry out a wide range of astrophysical studies, including optical support for the localization of gravitational waves and other transient events. 相似文献
14.
RXTE observations of the X-ray binary systems SXP 138, GX-304, and γ Cas in 1997–2011 have shown for the first time that these objects (X-ray binaries with Be donors) display X-ray flux variations on timescales of ～1000 days. This timescale is about 10 times longer than their orbital periods, and is comparable to the total time of the observations. The observed variations are apparently not strictly periodic and represent stochastic variability, as is characteristic of such systems in the optical. γ Cas is considered as an example. The series of optical observations of this system available in the AAVSO database covers 78 years, and is much longer than the timescale of the variability studied. Our analysis of this series has shown that γ Cas variability on a timescale of tens of years is predominantly stochastic with a power-law spectrum. 相似文献
15.
The system of radiative-transfer equations for polarized radiation is solved analytically using an azimuth-averaged Hanle
phase matrix. A Milne-Eddington model with a constant ratio of the line and continuum absorption coefficients and a linear
dependence of the source function on optical depth is adopted for the atmosphere. The vector magnetic field is taken to be
constant with optical depth. The dependence of the linear polarization obtained during observations at the solar limb on the
magnitude and inclination of the magnetic field to the normal of the atmosphere is presented as an illustration of the theoretical
computations. The measured polarization corresponds to two magnetic-field values and several possible field inclinations.
The measured polarization is directly proportional to the quantum coefficient W
2 determining the resonance polarization in lines. 相似文献
16.
The most powerful flare ever registered in the Galactic water-maser source W49N has been detected in long-term monitoring data in the 616–523 transition with line frequency f = 22.235 GHz carried out on the 22-m Simeiz, 32-m Toruń, 100-m Effelsberg, and 32-m Medicina radio telescopes, beginning in September 2017 and continuing in 2018. Some stages of the flare were monitored daily. Detailed variations of the source spectral flux density with time have been obtained. At the flare maximum, the flux exceeded P ≈ 8 × 104 Jy, and this was record highest flux registered over the entire history of observations of this source. Important conclusions related to details of the mechanism for the H2O line emission have been drawn. An exponential increase in the flare flux density was detected during both the rise and decline of the flare. The data obtained indicate that the maser is unsaturated, and remained in this state up to the maximum observed flux densities. Additional support for the idea that the maser is unsaturated is the shape of the dependence of the line width on the flux. The characteristics of the variations of the spectral flux density are probably associated with a sharp increase in the density of the medium and the photon flux that led to an increase in the temperature from an initial level of 10–40 K to hundreds of Kelvins. Interferometric maps of the object during the increase in the spectral flux density of the flare have been obtained. A possible mechanism for the primary energy release in W49N is considered. 相似文献
17.
Flux-density variations of the quasar S0528+134 (Nimfa) are analyzed based on long-term monitoring at five radio frequencies between 4.8 and 37 GHz, performed at the Crimean Astrophysical Observatory, the Metsähovi Radio Observatory of Aalto University, and the University of Michigan Radio Astronomy Observatory. The dynamics of a powerful flare in 1996 are analyzed using gamma-ray (0.1–300 GeV), X-ray (2–10 keV, 15–50 keV), and radio observations. The delays of the flare between different spectral ranges and between different radio wavelengths have been measured. The dependence for the delays at different radio wavelengths relative to the X-ray and optical flares is established based on long-term observations in the X-ray, optical, and radio obtained from 2004 to 2013. Multi-frequency monitoring in the radio is used to estimate the orbital and precession periods in the binary supermassive black hole system S0528+134 and the physical characteristics of this system. 相似文献
18.
We present the results of simultaneous UBVRI photometric and polarimetric observations of the Ae Herbig star SV Cep made in 1987–1998. Over these 11 years, only a single deep (Δ V>1 m) brightness minimum was observed. Near this minimum, the brightness decrease was accompanied by an increase of the linear polarization, as is typical of young UX Ori stars. The photometric observations of SV Cep indicate reversals of the color tracks in brightness minima, as is common for stars of this type, as well as variations of the slopes of the color tracks during and after minima. This provides evidence that the circumstellar dust clouds screening the star differ in their sizes and masses, and also in the optical properties of their dust particles. A Fourier analysis of the brightness variations of SV Cep (including data from the literature) confirms the presence of previously suspected activity cycles with periods P 1=4000 d and P 2=670 d The polarimetric observations indicate that, along with the inverse correlation between the degree of linear polarization and brightness, the polarization parameters vary on characteristic time scales of 4000 and 1000 days. This suggests the existence of large-scale inhomogeneities in the circumstellar dust disk rotating about the star. 相似文献
19.
An analysis of data from three years of monitoring of interplanetary scintillations in 2015–2017 during a phase of decreasing solar activity is presented. The observations were carried out on the Large Scanning Antenna of the Lebedev Physical Institute at 111 MHz. During the period considered, the spatial distriution of the scintillation level was close to spherically symmetrical, on average, and did not undergo any strong time variations on scales of months or years. The monthly-mean scintillation level is not correlated with theWolf number. 相似文献
20.
The results of observations of the blazar J1504+1029 (PKS 1502+106, OR 103), obtained in 2000–2018 on the RATAN-600 radio telescope of the Special Astrophysical Observatory at 2.3, 3.9 (4.7), 7.7 (8.2), 11.2, and 21.7 GHz and on the 32-m Zelenchuk and Badary radio telescopes of the Quasar-KVO complex of the Institute of Applied Astronomy of the Russian Academy of Sciences at 5.05 and 8.63 GHz are presented. The long-term variability is studied, as well as variability on time scales from several days to several weeks and intraday variability (IDV). The long-term light curves are correlated at all frequencies and show continuous activity, against which three flares with their maxima in 2002, 2009, and 2018 are distinguished. The time scale for variability of the flare in 2009 is τvar ≈ 1 year. At 21.7 GHz, the linear size of the emitting region is R ≤ 0.3 pc, its angular size is θ ≤ 0.05 mas, its brightness temperature is Tb ≥ 2 × 1014 K, and the Doppler factor is δ ≥ 5.8. The flare with its maximum in 2018 has a long rising branch at 21.7 GHz: τvar = 3.2 years, linear size R ≤ 1.1 pc, angular size θ ≤ 0.17 μas, brightness temperature Tb ≥ 2.2 × 1012 K, and Doppler factor δ ≥ 2.8. Among eleven sets of daily observations of the source over 75–120 days in 2000–2017, variability was detected in eight data sets at two to four frequencies with characteristic time scales of 4–30 days. In seven data sets, the variability is due to one to three cyclic processes with characteristic time scales τacf = 4?30d. The spectral indices of the variable components in different years vary from αvar = ?1.6 to +1.8. In at least four data sets, the variability is due to processes in the source itself. In this case, at 21.7 GHz, the apparent linear size of the emitting region is ≤4000 AU, the angular size is θ ≤ 3.5 μas, the brightness temperature is Tb ≥ 3 × 1014 K, and the Doppler factor is δ ≥ 14. In the 2004 data set, the variability has an “ anti-flare” form, with the flux density of the variable component falling at high frequencies. Thirty-six successful sessions were conducted on the 32-m telescopes at 8.63 GHz, and 16 at 5.05 GHz. IDV was detected in 17 sessions at 8.63 GHz and in three sessions at 5.05 GHz, with the IDV being detected mainly near flare maxima. 相似文献
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