129 citations · 1.7k across the 78 of their papers we have counts for
48 papers · 1 filter
The Nearest Galactic Nucleus: Studying the Galactic Centre with SKA-Mid
Rainer Schoedel, Antxon Alberdi, Izaskun Jiménez-Serra +24
The Galactic Centre is the nearest nucleus of a galaxy and the most extreme environment that we can observe down to physical scales of a few hundred astronomical units. There is no…
Eclipses of Nearby Millimeter-bright Galactic Nuclei by Stars in Nuclear Star Clusters
Michal Zajaček
It is of a general interest to look for signatures of stellar bodies orbiting supermassive black holes (SMBHs) in galactic nuclei other than the Galactic center. Previously stellar…
High-cadence observations of galactic nuclei by the future two-band UV-photometry mission QUVIK
Michal Zajaček, Norbert Werner, Henry Best +12
The Quick Ultra-VIolet Kilonova surveyor (QUVIK), a two-band UV space telescope approved for funding as a Czech national science and technology mission, will focus on detecting ear…
A binary system in the S cluster close to the supermassive black hole Sagittarius A*
Florian Peißker, Michal Zajacek, Lucas Labadie +4
High-velocity stars and peculiar G objects orbit the central supermassive black hole (SMBH) Sagittarius A* (Sgr A*). Together, the G objects and high-velocity stars constitute the…
Discovery of a Dense Association of Stars in the Vicinity of the Supermassive Black Hole Sgr A*
S. Elaheh Hosseini, Andreas Eckart, Michal Zajaček +3
We focus on a sample of 42 sources in the vicinity of the bow-shock source IRS 1W (N-sources), located at the distance of north-east of the supermassive black hole (SMBH)…
The Evaporating Massive Embedded Stellar Cluster IRS 13 Close to Sgr A*. II. Kinematic structure
Florian Peißker, Michal Zajacek, Matus Labaj +8
The existence of two distinct and apparently unrelated populations of dusty stellar objects in the Nuclear Stellar Cluster (NSC) of the Milky Way, namely IRS 13 and the S-cluster,…
Candidate Young Stellar Objects in the S-cluster: The Kinematic Analysis of a Sub-population of the Low-mass G-objects close to Sgr A*
Florian Peißker, Michal Zajaček, Maria Melamed +5
The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty ob…
New theoretical Fe II templates for bright quasars
Ashwani Pandey, Mary Loli Martínez-Aldama, Bożena Czerny +5
We present a set of new theoretical Fe II templates for bright quasars covering a wavelength range of 1000-10000 Å\, based on the recent atomic database available in the C23.00 ver…
Broad-line region in active galactic nuclei: Dusty or dustless?
Ashwani Pandey, Bozena Czerny, Swayamtrupta Panda +5
Context. Dust in active galactic nuclei is clearly present right outside the broad-line region (BLR) in the form of a dusty molecular torus. However, some models of the BLR predict…
The Evaporating Massive Embedded Stellar Cluster IRS 13 Close to Sgr A*. I. Detection of a rich population of dusty objects in the IRS 13 cluster
Florian Peißker, Michal Zajaček, Lauritz Thomkins +6
A detailed analysis of the Nuclear Stellar Cluster (NSC) concedes not only the existence of the Scluster with its fast-moving stars and the supermassive black hole (SMBH) Sgr A*. I…
X3: a high-mass Young Stellar Object close to the supermassive black hole Sgr~A*
Florian Peißker, Michal Zajacek, Nadeen B. Sabha +10
To date, the proposed observation of Young Stellar Objects (YSOs) in the Galactic center (GC) still raises the question where and how these objects could have formed due to the vio…
Expectations for time-delay measurements in active galactic nuclei with the Vera Rubin Observatory
Bozena Czerny, Swayamtrupta Panda, Raj Prince +10
The Vera Rubin Observatory will provide an unprecedented set of time-dependent observations of the sky. The planned Legacy Survey of Space and Time (LSST) operating for 10 years wi…
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…
Black-hole activity feedback across vast scales
Michal Zajaček, Bożena Czerny, Rainer Schödel +2
Both observational and theoretical studies of black-hole activity or active galactic nucleus (AGN) feedback have been ongoing since the first indication of supermassive black holes…
Observation of S4716 -- a Star with a 4 yr Orbit around Sgr A*
Florian Peißker, Andreas Eckart, Michal Zajaček +1
The ongoing monitoring of the Galactic center and Sgr A*, the central supermassive black hole, produces surprising and unexpected findings. This goes hand in hand with the technica…
Mid-Infrared studies of dusty sources in the Galactic Center
Harshitha K. Bhat, Nadeen B. Sabha, Michal Zajaček +5
Mid-Infrared (MIR) images of the Galactic center show extended gas and dust features along with bright IRS sources. Some of these dust features are a part of ionized clumpy streame…
The apparent tail of the Galactic center object G2/DSO
Florian Peißker, Michal Zajacek, Andreas Eckart +6
The observations of the near-infrared excess object G2/DSO induced an increased attention towards the Galactic center and its vicinity. The predicted flaring event in 2014 and the…
First observed interaction of the circumstellar envelope of an S-star with the environment of Sgr A*
Florian Peißker, Basel Ali, Michal Zajaček +7
Several publications highlight the importance of the observations of bow shocks to learn more about the surrounding interstellar medium and radiation field. We revisit the most pro…
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…
Constraining the accretion flow density profile near Sgr A* using the -band emission of the S2 star
S. Elaheh Hosseini, Michal Zajaček, Andreas Eckart +2
The density profile of the ambient medium around a supermassive black hole plays an important role in understanding the inflow-outflow mechanisms in the Galactic Centre. We constra…
S62 and S4711: Indications of a population of faint fast moving stars inside the S2 orbit -- S4711 on a 7.6 year orbit around Sgr~A*
Florian Peißker, Andreas Eckart, Michal Zajaček +2
We present high-pass filtered NACO and SINFONI images of the newly discovered stars S4711-S4715 between 2004 and 2016. Our deep H+K-band (SINFONI) and K-band (NACO) data show the S…
Scatter Analysis Along the Multidimensional Radius-Luminosity Relations for Reverberation-Mapped Mg II Sources
Mary Loli Martínez-Aldama, Michal Zajaček, Bożena Czerny +1
The usage of the radius-luminosity (R-L) relation for the determination of black hole masses across the cosmic history as well as its application for cosmological studies motivates…
Kinematic Structure of the Galactic Center S-cluster
Basel Ali, Daria Paul, Andreas Eckart +7
We present a detailed analysis of the kinematics of 112 stars that mostly comprise the high velocity S-cluster and orbit the super massive black hole SgrA* at the center of the Mil…