L. V. Larionova
A5025377390- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Particle Accelerators and Free-Electron Lasers
- Astronomy and Astrophysical Research
- Gyrotron and Vacuum Electronics Research
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Soil and Unsaturated Flow
- Scientific Measurement and Uncertainty Evaluation
- Geophysics and Gravity Measurements
- Mechanics and Biomechanics Studies
- Dam Engineering and Safety
- Tunneling and Rock Mechanics
- International Relations and Foreign Policy
- melanin and skin pigmentation
- Galaxies: Formation, Evolution, Phenomena
- Particle physics theoretical and experimental studies
- Astro and Planetary Science
- Antioxidant Activity and Oxidative Stress
St Petersburg University
2013-2024
Institute of Applied Astronomy
2006-2018
We present results from monitoring the multi-waveband flux, linear polarization, and parsec-scale structure of quasar PKS 1510-089, concentrating on eight major gamma-ray flares that occurred during interval 2009.0-2009.5. The peaks were essentially simultaneous with maxima at optical wavelengths, although flux ratio two wavebands varied by an order magnitude. polarization vector rotated 720 degrees a 5-day period encompassing six these flares. This culminated in very bright, roughly 1 day,...
We analyze the behavior of parsec-scale jet quasar 3C 454.3 during pronounced flaring in 2005–2008. Three major disturbances propagated down along different trajectories with Lorentz factors Γ > 10. The show a clear connection millimeter-wave outbursts, 2005 May/June, 2007 July, and December. High-amplitude optical events R-band light curve precede peaks outbursts by 15–50 days. Each outburst is accompanied an increase X-ray activity. associate propagation superluminal knots derive location...
We present time-resolved broad-band observations of the quasar 3C 279 obtained from multi-wavelength campaigns conducted during first two years Fermi Gamma-ray Space Telescope mission. While investigating previously reported gamma-ray/optical flare accompanied by a change in optical polarization, we found that emission appears delayed with respect to gamma-ray about 10 days. X-ray reveal pair `isolated' flares separated ~90 days, only weak counterparts. The spectral structure measured...
We analyze the multifrequency behavior of quasar 3C 454.3 during three prominent \gamma-ray outbursts: 2009 Autumn, 2010 Spring, and Autumn. The data reveal a repeating pattern, including triple flare structure, in properties each outburst, which implies similar mechanism(s) location for all events. multi-frequency indicates that lower frequency events are co-spatial with outbursts, although emission varies on shortest timescales. determine variability from UV to IR wavelengths an outburst...
We present the results of optical (R band) photometric and polarimetric monitoring Very Long Baseline Array (VLBA) imaging blazar S5 0716+714 along with Fermi gamma-ray data during a multi-waveband outburst in 2011 October. analyze total polarized intensity images obtained VLBA at 43 GHz after outburst. Monotonic rotation linear polarization vector rate >50 degrees per night coincided sharp maximum flux. At same time, within uncertainties, new superluminal knot appeared, an apparent speed...
Since the launch of Fermi satellite, BL Lacertae has been moderately active at gamma-rays and optical frequencies until May 2011, when source started a series strong flares. The exceptional sampling achieved by GLAST-AGILE Support Program (GASP) Whole Earth Blazar Telescope (WEBT) in collaboration with Steward Observatory allows us to perform detailed comparison daily gamma-ray observations Fermi. Discrete correlation analysis between emission reveals time lag 0 +- 1 d, which suggests...
The radio quasar 3C 454.3 underwent an exceptional optical outburst lasting more than 1 year and culminating in spring 2005. maximum brightness detected was R = 12.0, which represents the most luminous state thus far observed (M_B ~ -31.4). In order to follow emission behaviour of source detail, a large multiwavelength campaign organized by Whole Earth Blazar Telescope (WEBT). Continuous optical, near-IR monitoring performed several bands. ToO pointings Chandra INTEGRAL satellites provided...
Context. The quasar 3C 279 is among the most extreme blazars in terms of luminosity and variability flux at all wavebands. Its variations polarization are quite complex therefore require intensive monitoring observations multiple wavebands to characterise interpret observed changes.
Context. Over the past few years, on several occasions, large, continuous rotations of electric vector position angle (EVPA) linearly polarized optical emission from blazars have been reported. These events are often coincident with high energy γ-ray flares and they attracted considerable attention, since could allow us to probe magnetic field structure in emitting region jet. The flat-spectrum radio quasar 3C 279 is one most prominent examples showing this behaviour.
Aims. The Whole Earth Blazar Telescope (WEBT) consortium has been monitoring the blazar 3C 454.3 from radio to optical bands since 2004 study its emission variability properties.
We present the results of polarimetric (R-band) and multicolor photometric (BH RI J H K) observations blazar AO 0235+16 during an outburst in 2006 December. The data reveal a short timescale variability (several hours), which increases from optical to near-IR wavelengths; even shorter variations are detected polarization. flux density correlates with degree polarization, at maximum polarization electric vector tends align parsec-scale jet direction. find that variable component steady...
Since 1997, BL Lacertae has undergone a phase of high optical activity, with the occurrence several prominent outbursts. Starting from 1999, Whole Earth Blazar Telescope (WEBT) consortium organized various multifrequency campaigns on this blazar, collecting tens thousands data points. One main issues in study huge dataset been search for correlations between and radio flux variations, possible periodicities light curves. The analysis assembled during first four (comprising also archival to...
We present multiwavelength observations of 3C 454.3 from April 2008 to March 2010. The radio optical data are mostly the GASP-WEBT, UV and X-ray Swift, gamma-ray AGILE Fermi satellites. improved calibration optical-UV UVOT OM instruments estimated Lyalpha flux disentangle contributions different components in this spectral region. reveal prominent variability above 8 GHz. In band, amplitude decreases with increasing frequency due a steadier radiation both broad line region an accretion disc....
The quasar-type blazar 4C 38.41 (B3 1633+382) experienced a large outburst in 2011, which was detected throughout the entire electromagnetic spectrum. We present results of low-energy multifrequency monitoring by GASP project WEBT consortium and collaborators, as well those spectropolarimetric/spectrophotometric at Steward Observatory. also analyse high-energy observations Swift Fermi satellites. In optical-UV band, several indicate that there is contribution from QSO-like emission...
We perform a multi-wavelength polarimetric study of the quasar CTA 102 during an extraordinarily bright γ-ray outburst detected by Fermi Large Area Telescope in 2012 September–October when source reached flux F>100 MeV = 5.2 ± 0.4 × 10−6 photons cm−2 s−1. At same time, displayed unprecedented optical and near-infrared (near-IR) outburst. evolution parsec-scale jet with ultra-high angular resolution through sequence 80 total polarized intensity Very Long Baseline Array images at 43 GHz,...
After several years of quiescence, the blazar CTA 102 underwent an exceptional outburst in 2012 September–October. The flare was tracked from γ-ray to near-infrared (NIR) frequencies, including Fermi and Swift data as well photometric polarimetric observatories. An intensive Glast-Agile support programme Whole Earth Blazar Telescope (GASP–WEBT) collaboration campaign optical NIR bands, with addition previously unpublished archival extension through fall 2015, allows comparison this previous...
We report the results of decade-long (2008-2018) $\gamma$-ray to 1 GHz radio monitoring blazar 3C 279, including GASP/WEBT, $\it{Fermi}$ and $\it{Swift}$ data, as well polarimetric spectroscopic data. The X-ray light curves correlate well, with no delay > 3 hours, implying general co-spatiality emission regions. $\gamma$-ray-optical flux-flux relation changes activity state, ranging from a linear more complex dependence. behaviour Stokes parameters at optical wavelengths, 43 VLBA images,...
Context.In spring 2005 the blazar 3C 454.3 was observed in an unprecedented bright state from near-IR to hard X-ray frequencies. A mm outburst peaked June–July 2005, and it followed by a flux increase at high radio
The quasar 3C 279 was the target of an extensive multiwavelength monitoring campaign from 2006 January through April. An optical-IR-radio by Whole Earth Blazar Telescope (WEBT) collaboration organized around target-of-opportunity X-ray and soft γ-ray observations with Chandra INTEGRAL in mid-January, additional coverage RXTE Swift XRT. In this paper we focus on results WEBT campaign. source exhibited substantial variability optical flux spectral shape, a characteristic timescale few days....
<i>Context. <i/>BL Lacertae is the prototype of blazar subclass named after it. Yet, it has occasionally shown a peculiar behaviour that questioned simple interpretation its broad-band emission in terms synchrotron plus self-Compton (SSC) radiation.<i>Aims. <i/>In 2007–2008 observing season we carried out new multiwavelength campaign Whole Earth Blazar Telescope (WEBT) on BL Lacertae, involving three pointings by XMM-Newton satellite July and December 2007, January 2008, to study properties,...
A multifrequency campaign on the BL Lac object PG 1553+113 was organized by Whole Earth Blazar Telescope (WEBT) in 2013 April-August, involving 19 optical, two near-IR, and three radio telescopes. The aim to study source behaviour at low energies during around high-energy observations Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes April-July. We also analyse UV X-ray data acquired Swift XMM-Newton satellites same period. WEBT satellite allow us detail synchrotron emission...
We report on long-term multi-wavelength monitoring of blazar Mrk 421 by the GASP-WEBT collaboration and Steward Observatory, Swift Fermi satellites. study source behaviour in period 2007-2015, characterized several extreme flares. The ratio between optical, X-ray, \gamma-ray fluxes is very variable. flux variations show fair correlation with optical ones starting from 2012. analyse spectropolarimetric data find wavelength-dependence polarisation degree (P), which compatible presence host...
We present a multiwavelength spectral and temporal analysis of the blazar OJ 287 during its recent activity between 2015 December 2016 May, showing strong variability in near-infrared (NIR) to X-ray energies with detection at γ-ray as well. Most optical flux variations exhibit changes polarization angle degree. All interband time lags are consistent simultaneous emissions. Interestingly, on days excellent data coverage NIR–UV bands, energy distributions (SEDs) show signatures bumps...