Although it is well understood that supermassive black holes are found in essentially all galaxies, the mechanisms by which they initially form remain highly uncertain, despite the importance that the formation pathway can have on AGN and quasar behaviour at all redshifts. Using a post-processing analysis method combining cosmological simulations and analytic modeling, I will discuss how varying the conditions for formation of supermassive black hole seeds leads to changes in AGN populations. Looking at formation via direct collapse or from PopIII remnants, I will discuss the impact on black hole mass and luminosity functions, scaling relations, and black hole mergers, which each have effects at both high- and low-redshifts. In addition to demonstrating the importance of initial seed formation on our understanding of long-term black hole evolution, I will also show that the signatures of seed formation suggest multiple means by which upcoming electromagnetic and GW surveys (at both high- and low-z) can provide the data required to constrain initial supermassive black hole formation.

We have made a spectroscopic survey of luminous AGNs and quasars selected in the mid-infrared from Spitzer IRAC surveys. Mid-infrared selection is less affected by dust obscuration, and we find more high redshift quasars than are found in optical or hard X-ray surveys. We have derived luminosity functions for obscured and unobscured quasar populations, and we use these and spectral energy distribution fits to place constraints on host galaxy properties and quasar lifetimes.

An extended magnetosphere of a strongly magnetized accreting white dwarf (known as a polar) prevents the formation of an accretion disk and the matter is channelled to the magnetic pole(s). A few such sources show quasi-periodic oscillations in their optical light curves. These high-frequency oscillations are thought to be generated from the post-shock accretion column. The kinetic energy of the accretion flow is finally emitted from this post-shock region and the involved radiation processes decide the state of the matter. Here we study the structure and the dynamical properties of such accretion columns and compare the results with the observational characteristics.

We present an updated public version of EPM (Ephemerides of Planets and the Moon). Since the last public version, EPM2017, many improvements were made in both the observational database and the mathematical model. Latest lunar laser ranging observations have been added, as well as radio ranges of Juno spacecraft and more recent ranges of Odyssey and Mars Reconnaissance Orbiter. EPM2021 uses a new improved way to calculate radio signal delays in solar plasma and has a major update in the method of determination of asteroid masses. Also, a delay-capable multistep numerical integrator was implemented for EPM in order to properly account for tide delay in the equations of the motion of the Moon. The improved processing accuracy has allowed to refine existing estimates of the mass of the Sun and its change rate, parameters of the Earth–Moon system, masses of the Main asteroid belt and the Kuiper belt; and also to raise important questions about existing numerical models of solar wind.

A summary in a timeline of astronomy developments over the past several decades and listing major achievements and current work will be presented.

The variation of optical continuum and broad emission lines is observed in all type 1 active galactic nuclei (AGN). In some cases even extreme variability is detected when broad-line profiles completely disappear as is the case in the co-called changing-look AGN, which raise new question on the theoretical model of AGN. This variability is an important tool to study the physics and geometry of the broad line region (BLR), e.g. it can be used to estimate its size through the reverberation mapping technique. Especially, long-term campaigns give new insights, like the detection of the periodic signals or discoveries of changing-look AGN. Here we will present the results of our long-term monitoring campaign of several well-known AGN, as e.g. NGC 3516 for which we confirm that it is the changing-look AGN, putting special attention of the applications for future large time-domain spectroscopic surveys, like the MaunaKea Spectroscopic Explorer project.

Many intermediate polars are hard X-ray sources. The theory of their hard X-ray radiation is well developed and allows us to determine white dwarf masse in this kind of cataclysmic variables. Here we present the results of determination the masses of 35 white dwarfs in the intermediate polars observed by observatories NuSTAR (10 sources) and Swift/BAT (25 sources). The corresponding mass accrerion rates and the luminosity function were also derived due to accurate distance to the sources well known now after Gaia DR2.

We present first results from our study of the host galaxies and environments of quasars in Galaxy And Mass Assembly (GAMA), a multiwavelength photometric and spectroscopic survey for ∼300,000 galaxies over ∼300 deg2, to a limiting magnitude of r ∼ 20 mag. We use a GAIA-selected sample of ∼350 quasars at z < 0.3 in GAMA. For all the quasars, we determine all surrounding GAMA galaxies and measure their star formation (SF) rate and SF history, and the host galaxy morphology and group membership of the quasars. As a comparison sample of inactive galaxies, we use 1000 subsets of galaxies in GAMA, matched in redshift and galaxy stellar mass to the quasars. We find that quasar activity does not depend on the large-scale environment (cluster/group/void), although quasars tend to prefer satellite location in their environment. Compared to inactive galaxies, quasars are preferentially hosted in bulge-dominated galaxies and have higher SF rates, both overall and averaged over the last 10 and 100 Myr. Quasars also have shorter median SF timescales, shorter median time since the last SF burst, and higher metallicity than inactive galaxies. We discuss these results in terms of triggering mechanisms of the quasar activity and the role of quasars in galaxy evolution.

We present 1-second cadence, precise optical observations from SOFIA and Palomar of a sample of nearby supermassive black holes. The observations were taken to identify the shortest timescale variability in the nuclear photometry which may be associated with instabilities in the accretion flow in the immediate vicinity of the black hole. The shortest timescale variability, if associated with the radius of the innermost stable circular orbit (ISCO), can then be used to estimate the spin of the black hole. Despite 1% precision photometry, we obtained a non-detection of any significant variability in the nucleus of M32 (Mbh ∼ 2.5 × 106 Mȯ). Given the density of the stellar cusp, this argues for a scenario where 1000 Msun seed black holes formed from the coalescence of less massive black holes, which then accrete the gas produced by stellar interactions/winds. In more luminous systems however, we find a significant deection of variability and present hypotheses to explain the signal and thereby the origin of supermassive black holes.

Low luminosity AGN represent the vast majority of the AGN population in the near universe, and still the least conforming class with the standard AGN scenario. Their low luminosity is at odds with their often very high black hole masses and powerful jets. I will review the challenges that parsec-scale observations across the electromagnetic spectrum of some of the nearest ones are opening on the true nature of their emission, their transition from the most luminous to the feeble ones, and their accretion power. The strict limits imposed by these observations on their accretion power are confronted with the high mechanical energy inferred for their jets. Possible scenarios for these nuclei including the extraction of power form the black hole spin are discussed (Prieto et al. 2016; Fernandez-Ontiveros et al. 2019).

Host galaxy morphology studies of jetted narrow-line Seyfert 1 galaxies (NLS1) are scarce. Although it seems that they are mostly hosted by late-type galaxies the results remain inconclusive, mostly due to the small sample size. Increasing the number of studied sources is crucial to achieve statistically significant results and to establish a preferred host type for jetted NLS1s. To this end we observed the host galaxies of nine NLS1s in near-infrared using NOTCam at the Nordic Optical Telescope. Seven of these sources are jetted based on the 37 GHz observations at Metsähovi Radio Observatory, Finland. To determine the morphological types of the hosts we performed photometric decomposition of the near-infrared images using GALFIT. Here we present the results of the host galaxy modelling, discuss the importance of this study to our understanding of the nature of the diverse NLS1 population, as well as its significance and implications for active galactic nuclei research in general.

I will present our ongoing multi-wavelength study on the prevalence and impact of radio jets in a sample of z < 0.2 type 2 ‘obscured’ quasars who’s high bolometric luminosities make them ideal local analogues of distant, more common, quasars. Despite being classified as ‘radio quiet’ (log L[1.4GHz] = 23.3 - 24.4 W/Hz), our high spatial resolution (∼0.25”) radio observations (VLA and eMERLIN) reveal jet like structures on 1–25kpc scales in ∼80% of the sample. Our integral field spectroscopy reveals jet-ISM interaction and outflows in all cases. Our work suggests that radio jets are an important feedback mechanism even during a typical ‘quasar’ phase. Using ALMA and APEX we are now investigating the impact of these jets and outflows on the molecular, star forming, gas; looking for signs of depletion and excitation. Preliminary results suggest a depleted molecular gas supply in these sources. I will present all of these results, focused on our pilot study of 10 targets and then introduce our on-going work on an expanded sample of 42 low-redshift quasars. Our latest results come from MUSE/AO and ALMA from which we are carefully characterising the properties of the ionised and molecular outflows at sub-kpc resolution.

AGN feedback, through either radiation or kinematics by expelled medium, plays a crucial role in the coevolution of supermassive black hole (SMBH) and its host galaxy. The nuclei spend most of their time as low-luminosity AGNs (LLAGNs), whose spectra are distinctive to bright AGNs, and the feedback is the hot mode (also named kinetic mode). We thus investigate the radiative heating in the hot mode. We calculate the value of “Compton temperature” Tc, which defines the heating capability of the radiation at given flux, and find that Tc∼(5−15)×107 K, depending on the spectrum of individual LLAGNs. This work provides a cheap way to include the radiative heating of LLAGNs in the study of AGN feedback.

Planetary materials orbiting white dwarf stars reveal the ultimate fate of the planets of the Solar System and all known transiting exoplanets. Observed metal pollution and infrared excesses from debris disks support that planetary systems or their remnants are common around white dwarf stars; however, these planets are difficult to detect since a very high orbital inclination angle is required for a small white dwarf to be transited, and these transits have very short (minute) durations. The low odds of catching individual transits could be overcome by a sufficiently wide and fast photometric survey. I demonstrate that, by obtaining over 100 million images of white dwarf stars with 30-second exposures in its first three years, the Zwicky Transient Facility (ZTF) is likely to record the first exoplanetary transits of white dwarfs, as well as new systems of transiting, disintegrating planetesimals. In these proceedings, I describe my project strategy to discover these systems using the ZTF data.

Several models of the solar luminosity, , in the evolutionary timescale, have been computed as a function of time. However, the solar mass-loss, , is one of the drivers of variation in this timescale. The purpose of this study is to model mass-loss varying solar luminosity, , and to predict the luminosity variation before it leaves the main sequence. We numerically computed the up to 4.9 Gyrs from now. We used the solution to compute the modeled . We then validated our model with the current solar standard model (SSM). The shows consistency up to 8 Gyrs. At about 8.85 Gyrs, the Sun loses 28% of its mass and its luminosity increased to 2.2. The model suggests that the total main sequence lifetime is nearly 9 Gyrs. The model explains well the stage at which the Sun exhausts its central supply of hydrogen and when it will be ready to leave the main sequence. It may also explain the fate of the Sun by making some improvements in comparison to previous models.

Blazars are radio-loud Active Galactic Nuclei (AGN) with relativistic jets oriented towards the observer’s line-of-sight. Based on their optical spectra, blazars may be classified as flat-spectrum radio quasars (FSRQs) or BL Lacs. FSRQs are more luminous blazars with both narrow and broad emission and absorption lines, while BL Lacs are less luminous and featureless. Recent studies show that blazars dominate (˜93%) the already-identified EGRET sources (142), suggesting that among the unidentified sources (129) there could still be faint blazars. Due to the presence of a strong non-thermal component inside their jets, blazars are found to display a weaker depression at ˜4000 Å (K 4000 ≤ 0.4). In this study, we aimed at determining the K 4000 break for a selected sample among the potential blazar candidates from unidentified EGRET sources to confirm their blazar nature. We used two blazar candidates, 3EG J1800-0146 and 3EG J1709-0817 associated with radio counterparts, J1802-0207 and J1713-0817, respectively. Their optical counterparts were obtained through spectroscopic observations using Robert Stobie spectrograph (RSS) at the Southern African Large Telescope (SALT) in South Africa. The observed Ca II H & K lines depression at ˜4000 Å in spectra of these sources show a shallow depression, K 4000 = 0.35 ± 0.02 and 0.24 ± 0.01, respectively, suggesting that these sources are blazar candidates. Moreover, the redshifts z = 0.165 and 0.26 measured in their spectra confirm the extragalactic nature of these sources.

The ionospheric critical frequency (foF2) from ionosonde measurements at geographic high, middle, and low latitudes are analyzed with the occurrence of coronal mass ejections (CMEs) in long term variability of the solar cycles. We observed trends of monthly maximum foF2 values and monthly averaged values of CME parameters such as speed, angular width, mass, and kinetic energy with respect to time. The impact of CMEs on foF2 is very high at high latitudes and low at low latitudes. The time series for monthly maximum foF2 and monthly-averaged CME speed are moderately correlated at high and middle latitudes.

Scaling relations are the most powerful astrophysical tools to set constraints to the physical mechanisms of astronomical sources and to infer properties for objects where they cannot be accessed directly. We have re-investigated one of these scaling relations using powerful type 1 Seyferts; the so-called X-ray variability plane (or mass-luminosity-timescale relation, McHardy et al.2006). This relation links the power-spectral density (PSD) break frequency with the SMBH mass and the bolometric luminosity. We used all available XMM-Newton observations to study the PSD and spectra in short segments within each observation. This allows us to report for the first time that the PSD break frequency varies for each object, showing variations in 19 out of the 22 AGN analyzed. Our analysis of the variability plane confirms the relation between the break frequency and the SMBH mass and finds that the obscuration along the line of sight (or the variations on the obscuration using its standard deviation) is also a required parameter. We constrain a new variability plane of the form: log(vBreak) = – A log (MBH) + B log (NH) – C (or log(vBreak) = – A log (MBH) + B Δ (NH) + C). The X-ray variability plane found by McHardy et al. (2006) is roughly recovered when we use unobscured segments. We speculate the PSD shape is related with the outflowing wind close to the accretion disk at least for these powerful type 1 AGN (Gonzalez-Martin et al. 2018).

In this study, we have investigated the stellar evolution models using the open-source software instrument Modules for Experiments in Stellar Astrophysics. We examine the evolution of angular momentum and the stability of mass transfer in the evolution of Algol-type binaries through the inner Lagrangian point via the Roche lobe overflow. Also, we have determined the ongoing challenge of chemical mixing and exhibit improvements that make easier the simulation of Algol-type binaries evolution.

The objective of this paper is to carry out periodic orbital propagation and bifurcations detection around asteroid 433 Eros. Specifically, we propose to exploit a frequency-domain method, the harmonic balance method, as an efficient alternative to the usual time integration. The stability and bifurcations of the periodic orbits are also assessed thanks to the Floquet exponents. Numerous periodic orbits are found with various periods and shapes. Different bifurcations, including period doubling, tangent, real saddle and Neimark-Sacker bifurcations, are encountered during the continuation process. Resonance phenomena are highlighted as well.