A5065567315- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Calibration and Measurement Techniques
- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Mechanics and Biomechanics Studies
- Cosmology and Gravitation Theories
- High-Energy Particle Collisions Research
- Geophysics and Gravity Measurements
- Particle accelerators and beam dynamics
- Scientific Research and Discoveries
- Advanced Sensor Technologies Research
- Leaf Properties and Growth Measurement
- Multidisciplinary Science and Engineering Research
- Neutrino Physics Research
- Magnetic confinement fusion research
- Phase Equilibria and Thermodynamics
- Photocathodes and Microchannel Plates
National Centre for Nuclear Research
2020-2024
Nicolaus Copernicus Astronomical Center
2010-2020
Polish Academy of Sciences
2016-2020
Observatoire de la Côte d’Azur
2016
University of Geneva
2014-2015
Swiss Institute of Comparative Law
2015
University of Białystok
2009-2010
Although broad emission lines are the most reliable signature of nuclear activity a galaxy and location emitting material is well measured by reverberation method, physical cause formation line region remains unclear. We attempt to place some constraints on its origin. study properties accretion disk underlying region. find that effective temperature at radius corresponding region, as inferred from H$\beta$ line, universal in all monitored sources equal 1000 K. This value close limiting...
Abstract The concept of the quasar main sequence is very attractive since it stresses correlations between various parameters and implies underlying simplicity. In optical plane defined by width H β line ratio equivalent Fe ii to observed objects form a characteristic pattern. this paper we use physically motivated model explain distribution quasars in plane. Continuum modeled as an accretion disk with hard X-ray power law uniquely tight at basis observational scaling, broad-line region...
The physical origin of the Broad Line Region in Active Galactic Nuclei is still unclear despite many years observational studies. reason that region unresolved and reverberation mapping results imply complex velocity field. We adopt a theory-motivated approach to identify principal mechanism responsible for this phenomenon. consider possibility role dust essential. assume local radiation pressure acting on accretion disk atmosphere launches outflow material, but higher above irradiation from...
High redshift quasars can be used to deduce the distribution of dark energy in Universe, as a complementary tool SN Ia. The method is based on determination size Broad Line Region from emission line delay, absolute monochromatic luminosity either observed statistical relation or model formation Region, and flux photometry. This allows obtain distance quasar independently its redshift. accuracy measurements however, key issue. We expected by creating artificial lightcurves responses under...
Using the six years of spectroscopic monitoring luminous quasar HE 0435-4312 ($z=1.2231$) with Southern African Large Telescope (SALT), in combination photometric data (CATALINA, OGLE, SALTICAM, and BMT), we determined rest-frame time-delay $296^{+13}_{-14}$ days between MgII broad-line emission ionizing continuum using seven different inference methods. Artefact peaks aliases were mitigated bootstrap method, prior weighting probability function as well by analyzing unevenly sampled mock...
We present the monitoring of AGN continuum and MgII broad line emission for quasar HE 0413-4031 ($z=1.38$) based on six-year by South African Large Telescope (SALT). managed to estimate a time-delay $302.6^{+28.7}_{-33.1}$ days in rest frame source using seven different methods: interpolated cross-correlation function (ICCF), discrete correlation (DCF), $z$-transformed DCF, JAVELIN, two estimators data regularity (Von Neumann, Bartels), $\chi^2$ method. This is below value expected from...
The spin of a black hole is an important parameter which may be responsible for the properties inflow and outflow material surrounding hole. broad-band infrared (IR)/optical/ultraviolet (UV) spectrum quasar SDSS J094533.99+100950.1 clearly disc-dominated, with peaking in observed frequency range. Therefore, disc-fitting method usually used Galactic holes can this object to determine spin. We develop numerical code computing disc properties, including radius-dependent hardening factor, apply...
Context. FeII emission is a well-known contributor to the UV spectra of active galactic nuclei and modeling this part may affect results obtained for MgII λ 2800 emission, which one lines used black hole mass measurements cosmological applications. Aims. We tested different models when intermediate-redshift quasar HE 0413−4031 see how use specific template affects line properties measurement time delays with respect continuum. Methods. 11-year monitoring selected South African Large...
Weak emission line quasars are a rare and puzzling group of objects. In this paper, we present one more object class found in the Sloan Digital Sky Survey (SDSS). The quasar SDSS J094533.99+100950.1, lying at z= 1.66, has practically no C iv line, red continuum very similar to second steepest composite spectra Richards et al., is not strongly affected by absorption Mg ii although relatively weak, strong enough measure black hole mass. Eddington ratio about 0.45, properties consistent with...
The black hole mass measurement in active galaxies is a challenge, particularly sources where the reverberation method cannot be applied. We aim to determine very special object, RE J1034+396, one of two AGN with QPO oscillations detected X-rays, and single bright optical band totally dominated by starlight. fit stellar content using code starlight, broad disk contribution optical/UV/X-ray emission modeled optxagnf. also several other independent methods. Various methods give contradictory...
ABSTRACT We show that the recently observed suppression of gap between broad-line region (BLR) and narrow-line (NLR) in some active galactic nuclei (AGNs) can be fully explained by an increase gas density emitting region. Our model predicts formation intermediate-line (ILR) is Seyfert galaxies detection emission lines with intermediate-velocity FWHM ∼ 700–1200 km s −1 . These are believed to originating from ILR located somewhere BLR NLR. As was previously proved, apparent assumed caused...
Most results of the reverberation monitoring active galaxies showed a universal scaling time delay Hbeta emission region with monochromatic flux at 5100 A, very small dipersion. Such favored dust-based formation mechanism Broad Line Region (BLR). Recent measurements that actually significant fraction objects exhibits horter lags than previously found scaling. Here we demonstrate these shorter can be explained by old concept BLR size ionization parameter. Assuming value this parameter and...
We report 6 yr monitoring of a distant bright quasar CTS C30.10 (z = 0.90052) with the Southern African Large Telescope (SALT). measured rest-frame time-lag $562\pm 2$ days between continuum variations and response Mg II emission line, using Javelin approach. More conservative approach, based on five different methods, imply time delay $564^{+109}_{-71}$ days. This delay, combined other available measurements line mostly for lower redshift sources, shows that reverberation implies...
We analyzed a large sample of radio-loud and radio-quiet quasar spectra at redshift 1.0 < z 1.2 to compare the inferred underlying continuum slopes (after removal host galaxy contribution) with accretion disk models. The latter predict redder (decreasing) alpha_3000 (L_\nu~\nu^alpha 3000Ang) increasing black hole mass, bluer luminosity 3000Ang, spin hole, when all other parameters are held fixed. find no clear evidence for any these predictions in data. In particular we that: (i) shows...
Context. We present the wavelength-resolved reverberation mapping (RM) of combined Mg II and UV Fe broad-line emissions for two intermediate-redshift ( z ∼ 1), luminous quasars, HE 0413-4031 0435-4312, monitored by Southern African Large Telescope (SALT) 1m class telescopes between 2012 2022. Aims. Using a technique, we aim to disentangle emission regions build radius–luminosity (R–L) relation emission, which has so far remained unconstrained. Methods. applied several time-delay...
The Mg II line is of extreme importance in intermediate redshift quasars since it allows us to measure the black hole mass these sources and use as probes distribution dark energy Universe, a complementary tool SN Ia. Reliable requires good understanding all systematic effects involved measurement properties, including contamination by Fe UV emission. We performed three spectroscopic observations quasar LBQS 2113-4538 (z = 0.956) with SALT telescope separated time several months we analyze...
Quasars can be used as a complementary tool to SN Ia probe the distribution of dark energy in Universe by measuring time delay emission line with respect continuum. The understanding Mg II structure is important for cosmological application and black hole mass measurements intermediate redshift quasars. knowledge shape its variability allows determine which part should measure mass. We thus aim at determination well underlying Fe pseudo-continuum. performed five spectroscopic observations...
We present the results of reverberation monitoring aimed at MgII broad line and FeII pseudocontinuum for luminous quasar CTS C30.10 (z = 0.90052) with Southern African Large Telescope covering years 2012-2021. disentangling UV variability first measurement time delay a distant quasar. used several methods time-delay measurements determined both delays as well performed wavelength-resolved study combination in 2700 - 2900 \AA restframe wavelength range. obtain $275.5^{+12.4}_{-19.5}$ days...
Abstract The requirement of an intermediate-line component in the recently observed spectra several active galactic nuclei (AGNs) points to possible existence a physically separate region between broad-line (BLR) and narrow-line (NLR). In this paper we explore emission from (ILR) by using photoionization simulations gas clouds distributed radially center AGN. span distances typical for BLR, ILR, NLR, appearance dust at sublimation radius is fully taken into account our model. structure...
Abstract This study is focused on the observational measurement of viewing angle individual quasars by modeling broadband quasar spectrum ranging from IR to soft X-ray band. Sources are selected various published catalogs, and their quasi-simultaneous spectral data points were collected used for modeling. We started with a COSMOS sample Type-1 sources that have photometric points. To include more points, we cross-matched Sloan Digital Sky Survey Data Release 14 catalog, eventually find 90...
Changing look active galactic nuclei (CLAGNs) show complex nature in their X-ray spectral shape and line of sight column density variation. The physical mechanisms responsible for these variations are unclear. Here, we study the properties a CLAGN, NGC\,1365 using combined {\it XMM-Newton} NuSTAR} observations to understand CL behavior. model fitted mass accretion rate varied between $0.003\pm 0.001$ $0.009\pm0.002$ $\dot M_{\rm Edd}$ dynamic corona changed from $28\pm 3$ $10\pm1$ $r_g$. We...
Owing to their thermal emission, tidal disruption events (TDEs) were regularly detected in the soft X-rays and sometimes optical. Only a few TDEs have been at hard X-rays: two are high redshift beamed events, one of which occurred core nearby galaxy, most recent is different nature, involving compact object Milky Way. The aims this work obtain first sample X-ray-selected unbeamed TDEs, determine frequency probe whether usually or exceptionally emit X-ray energies. We performed extensive...
Characterisation of the long-term variations in broad line region a luminous blazar, where Comptonisation broad-line emission within relativistic jet is standard scenario for production gamma-ray that dominates spectral energy distribution. We analysed ten years optical spectroscopic data from Steward Observatory blazar 3C 454.3, as well Fermi Large Area Telescope (LAT). The spectra are dominated by highly variable non-thermal synchrotron continuum with prominent Mg II line. flux was...