52 citations · 349 across the 26 of their papers we have counts for
26 papers
Radiation-pressure instability is an artifact of constant- closure. Implications for AGN disk tensions
M. H. Naddaf, M. Ghasemnezhad, H. Ghanbarnejad +2
The standard -disk formalism parametrizes turbulent angular momentum transport through a dimensionless coefficient , assumed to be spatially and thermodynamically invariant.…
Radiative filtering unifies broad-line phenomenology in active galactic nuclei
Mohammad Hassan Naddaf
Broad emission lines (BELs) are a defining feature of active galactic nuclei (AGNs), yet they weaken or disappear in both very low- and very high-accretion systems. These regimes a…
HALO II: Constraining Hubble constant through continuum delay fitting of Fairall 9
Amit Kumar Mandal, Francisco Pozo Nuñez, Vikram Kumar Jaiswal +28
The Hubble tension remains one of the most significant unresolved problems in modern cosmology. A key question is whether it may arise from underestimated systematic uncertainties…
HALO I: Photometric continuum reverberation mapping of Fairall 9
Amit Kumar Mandal, Francisco Pozo Nuñez, Vikram Kumar Jaiswal +23
We investigate the origin of inter-band continuum time delays in active galactic nuclei (AGNs) to study the structure and properties of their accretion disks. We aim to measure the…
Quasar Main Sequence unfolded by 2.5D FRADO (Natural expression of Eddington ratio, black hole mass, and inclination)
M. H. Naddaf, M. L. Martínez-Aldama, P. Marziani +2
The quasar main sequence (QMS), characterized by the Eigenvector 1 (EV1), serves as a unifying framework for classifying type-1 active galactic nuclei (AGNs) based on their diverse…
H line shape and radius-luminosity relation in 2.5D FRADO
M. H. Naddaf, M. L. Martinez-Aldama, D. Hutsemekers +2
Galaxies with active galactic nuclei (AGN) exhibit broad emission lines as a key spectral feature. The shape of emission-line profiles depends on the complex dynamics of discrete c…
The effect of outflow launching radial efficiency of accretion disk on the shape of emission-line profiles
Mohammad Hassan Naddaf
This paper presents a preliminary investigation into the influence of radial behavior of disk outflow on the structure and dynamics of the broad line region (BLR) in active galacti…
Covering factor of the dust-driven broad-line region clouds
Mohammad Hassan Naddaf, Bozena Czerny
The origin of the broad-line region (BLR) clouds in active galactic nuclei is still under discussion. We develop a scenario in which the clouds in the outer, less ionized part of t…
Multiwavelength study of extreme variability in LEDA 1154204: A changing-look event in a type 1.9 Seyfert
T. Saha, A. Markowitz, D. Homan +16
Context. Multiwavelength studies of transients in actively accreting supermassive black holes have revealed that large-amplitude variability is frequently linked to significant cha…
BAL effect in quasars due to source orientation
M. Sniegowska, M. H. Naddaf, M. L. Martinez-Aldama +3
We investigated a scenario where the presence of a broad absorption line (BAL) feature in quasars (QSOs) is contingent upon the line of sight being situated within an outflow cone…
Wavelength-resolved reverberation mapping of intermediate redshift quasars HE 0413-4031 and HE 0435-4312: Dissecting Mg II, optical Fe II, and UV Fe II emission regions
Raj Prince, Michal Zajaček, S. Panda +24
We present the wavelength-resolved reverberation mapping (RM) of combined MgII and UV FeII broad-line emissions for two intermediate redshifts (z1), luminous quasars - HE 041…
Dust-driven wind as a model of Broad Absorption Line quasars
Mohammad Hassan Naddaf, Mary Loli Martinez-Aldama, Paola Marziani +3
We test a scenario claiming that the broad absorption line (BAL) phenomenon in quasars (QSOs) is not a temporary stage of their life. In this scenario, we see the BAL effect only i…
Dusty plasma in active galactic nuclei
Bożena Czerny, Michal Zajaček, Mohammad-Hassan Naddaf +10
Since many years we know that dust in the form of the dusty-molecular torus is responsible for the obscuration in active galactic nuclei (AGN) at large viewing angles and thus for…
The Wind Dynamics of Super-Eddington Sources in FRADO
Mohammad-Hassan Naddaf, Bożena Czerny, Michal Zajaček
We perform non-hydrodynamical 2.5D simulations to study the dynamics of material above accretion disk based on the disk radiation pressure acting on dust. We assume a super-accreti…
Accretion disks, quasars and cosmology: meandering towards understanding
Bozena Czerny, Shulei Cao, Vikram Kumar Jaiswal +11
As Setti & Woltjer noted back in 1973, quasars could be used to construct the Hubble diagram but the actual application was not that straightforward. It took years to implement the…
Non-thermal emission from fall-back clouds in the Broad-Line Region of Active Galactic Nuclei
Ana Laura Müller, Mohammad-Hassan Naddaf, Michal Zajaček +3
The spectra of active galactic nuclei exhibit broad-emission lines that presumably originate in the Broad-Line Region (BLR) with gaseous-dusty clouds in a predominantly Keplerian m…
Wavelength-resolved Reverberation Mapping of quasar CTSC30.10: Dissecting MgII and FeII emission regions
Raj Prince, Michal Zajaček, Bożena Czerny +20
We present the results of the reverberation monitoring aimed at MgII broad line and FeII pseudocontinuum for the luminous quasar CTS C30.10 (z = 0.90052) with the Southern African…
Mass loss rate of accretion disk in FRADO
Mohammad-Hassan Naddaf, Bozena Czerny
We have developed the 2.5D version of the basic physically motivated 1D model of Czerny & Hryniewicz (2011), i.e. Failed Radiatively Accelerated Dusty Outflow (FRADO) model. This m…
Radiation pressure on dust explains the Low Ionized Broad Emission Lines in Active Galactic Nuclei
Mohammad-Hassan Naddaf, Bozena Czerny
Broad emission lines are the most characteristic features in the spectra of active galaxies. They mostly show either a single-peaked or double-peaked profiles; and originate from a…
The picture of BLR in 2.5-D FRADO: Dynamics & Geometry
Mohammad-Hassan Naddaf, Bozena Czerny, Ryszard Szczerba
The dynamics of the Broad Line Region (BLR) in Active galaxies is an open question, direct observational constraints suggest a predominantly Keplerian motion, with possible traces…
Time Delay of MgII Emission Response for the Luminous Quasar HE 0435-4312: Towards Application of High-Accretor Radius-Luminosity Relation in Cosmology
Michal Zajaček, Bożena Czerny, Mary Loli Martinez-Aldama +21
Using the six years of the spectroscopic monitoring of the luminous quasar HE 0435-4312 () with the Southern African Large Telescope (SALT), in combination with the photo…
Dark energy constraints from quasar observations
B. Czerny, M. L. Martínez-Aldama, G. Wojtkowska +9
Recent measurements of the parameters of the Concordance Cosmology Model (CDM) done in the low-redshift Universe with Supernovae Ia/Cepheids, and in the distant Universe done wi…
Time-delay measurement of MgII broad line response for the highly-accreting quasar HE 0413-4031: Implications for the MgII-based radius-luminosity relation
Michal Zajaček, Bożena Czerny, Mary Loli Martinez-Aldama +16
We present the monitoring of the AGN continuum and MgII broad line emission for the quasar HE 0413-4031 () based on the six-year monitoring by the South African Large Teles…
BLR size in Realistic FRADO Model: The role of shielding effect
Mohammad-Hassan Naddaf, Bozena Czerny, Ryszard Szczerba
The effective size of Broad Line Region (BLR), so-called the BLR radius, in galaxies with active galactic nuclei (AGN) scales with the source luminosity. Therefore by determining t…