abstract stringlengths 3 192k | title stringlengths 4 857 |
|---|---|
i will present observational theoretical work on the formation bulges and pseudo-bulges in galaxies at high and low redshifts. specifically, using the cosmological zoom-in simulations vela, i will show how typical galaxies on the star-forming main sequence at redshift 2 can form a bulge component through rapid gas infl... | bulge formation scenarios …perspectives from a high-z observer |
we model the optical/uv emission of the intermediate-mass black hole hlx-1, using three sets of hst observations (from 2010, 2012, 2013), together with xmm-newton and swift data. we quantify the relative contributions of a bluer component, function of x-ray irradiation, and a redder component, constant and likely comin... | explaining the outbursts of the intermediate-mass bh hlx-1 as a wind-driven instability |
redback millisecond pulsars (msps; hereafter redbacks) are a subpopulation of eclipsing msps in close binaries.the formation processes of these systems are not clear. the three pulsars showing transitions between rotation- andaccretion-powered states belong to both redbacks and transient low-mass x-ray binaries (lmxbs)... | from transient low-mass x-ray binaries to redback millisecond pulsars |
recurring outbursts associated with matter flowing onto compact stellar remnants (such as black holes, neutron stars and white dwarfs) in close binary systems provide constraints on the poorly understood accretion process. taken as a whole, the light-curves of these outbursts are shaped by the efficiency of angular-mom... | strong disc winds traced throughout outbursts in black-hole x-ray binaries |
the exponential shape of radial surface brightness profiles of disk galaxies has been observed and known for decades. however, the physical mechanism of its formation is not well understood. disturbances from bars and spiral arms, viscous accretion of gas, and interaction with surrounding galaxies can account for an ex... | formation of exponential profiles from stellar scattering investigated with n-body simulations |
atacama large millimeter/submillimeter array (alma) has revealed that the dust disk around the young star hl tau consists of multiple nearly concentric rings and gaps (alma partnership et al. 2015). the well separated rings indicate that the dust disk is geometrically thin, suggesting that the turbulence in the gas dis... | testing magnetic accretion models against alma observations of the hl tau disk |
the importance of major merging at z>1 remains in question despite the rapid buildup and development of massive galaxies at these epochs. new theories and observations suggest that non-merging processes like disk instabilities may be even more important than previously thought at assembling bulges, producing clumps,... | mining candels for tidal features to measure major merging at cosmic high noon |
the formation of directly imaged planets at wide separations is unclear and has become a major unanswered question in the field of exoplanets. core accretion plus dynamical scattering, in situ formation through disk instability, and turbulent cloud fragmentation all leave dynamical imprints on the orbits of these plane... | uncovering the formation of giant planets on wide orbits with astrometric orbit constraints |
a candidate companion to a very young star has been discovered in hst snapshot optical images. the object is projected at the outer radius of an edge-on protoplanetary disk and is aligned with the disk plane. keck lgs photometry results indicate the object has the same temperature as brown dwarf gq lupi b but with 10x ... | tracing interactions of a protoplanet with its circumstellar disk |
v630 cas and v1017 sgr are long-period cataclysmic variables withrare, long-duration, dwarf nova outbursts. the characteristics of theseoutbursts are likely shaped by the large physical size of the accretiondisks. they also appear to be luminous (> 10e33 ergs/s) x-ray sourcesin quiescence, severely challenging the d... | v630 cas and v1017 sgr: probing accretion disks on intermediate scales |
we perform a systematic study of the effect of sub-grid physics, resolution and structural parameters on the fragmentation of gas-rich galaxy discs into massive star forming clumps due to gravitational instability. we use the state-of-the-art zoom-in cosmological hydrodynamical simulation argo (fiacconi et al. 2015) to... | a lower fragmentation mass scale for clumps in high redshift galaxies: a systematic numerical study |
kepler revealed the common existence of tightly packed super earth systems around solartype stars, existing entirely inside the orbit ofour venus. those systems must be stable for the ages of their host stars (~10^9 years); their formation mechanism must provide interplanet spacings that permit longterm stability. if o... | consolidating and crushing exoplanets: did it happen here? |
accretion disks likely provide the conduit for fueling active galactic nuclei (agn), linking the black hole's immediate surroundings to the host galaxy's nuclear star cluster, and possibly beyond. yet detailed agn disk models fail to explain several of the most basic observational features of agn: how do the outer regi... | strongly magnetized accretion disks in active galactic nuclei |
the mass-metallicity-sfr (m-z-sfr) relation for galaxies gives insight into the accretion and outflow of gas. heightened accretion should increase disk turbulence and the corresponding jeans mass for gravitational instabilities, making star-formation clumpy, and it should also trigger star formation directly in large c... | the role of galaxy morphology in the mass-metallicity-sfr relation |
tidal disruption events, which occur when a star is destroyed by the gravitational field of a supermassive black hole, are unique probes of the inner regions of galaxies. in this thesis we explore various stages of the tidal disruption process, in an attempt to relate the observable signatures of tidal disruption event... | the evolutionary pathways of tidal disruption events: from stars to debris streams, accretion disks, and relativistic jets |
more than half of all stars are thought to be in binary or multiple star systems. but how do these systems form? the misaligned spins of some binary protostars might provide a clue.two formation modelsits hard to tell how multiple-star systems form, since these systems are difficult to observe in their early stages. bu... | exploring the birth of binary stars |
relatively evolved (~ 1 myr old) protostars with little residual natal envelope, but massive disks, are commonly assumed to be the sites of ongoing planet formation. critical to our study of these objects is information about the available mass reservior and dust structure, as they directly tie in to how much mass is a... | an alma survey of planet forming disks in rho ophiuchus |
previously we demonstrated that collisions between clumps of gas in the circum-nuclear disc can reduce their angular momentum and set some of the clumps on a plunging trajectory towards the supermassive black hole. if the central luminosity is determined by the gas accretion mechanism, then there exists a certain range... | influence of stellar component on the conditions for thermal instability in the galactic center minispiral region |
accretion is a ubiquitous process in astrophysics. in cases when the magnetic field is not too strong and a disk is formed, accretion can proceed through the mid plane all the way to the surface of the central compact object. unless that compact object is a black hole, a boundary layer will be formed where the accretio... | astrophysical boundary layers: a new picture |
the study of am cvn stars - semi-detached he wd-wd binaries - has exploded in recent years thanks to long term light curves obtained by the palomar transient factory. systems are seen withbinary periods ranging from about 5 minutes to about an hour. am cvn stars are similar to dwarfnovae in that they can undergo accret... | clues to the evolution of helium wd-wd binaries from the palomar transient factory |
multi-wavelength monitoring of accretion-instability (outburst)evolution of x-ray binaries is key to understanding the role of theblack hole event horizon, neutron star (ns) surface and magnetic fieldand the spin of the compact object, in the context of accretion and jetproduction. we propose to monitor one transient n... | the evolving multi-wavelength spectrum of a transient neutron star x-ray binary |
we present numerical analysis of the spin evolution of the neutron stars in low-mass x-ray binaries, trying to explain the discrepancy in the spin period distribution between observations of millisecond pulsars and theoretical results. in our calculations, we take account of possible effect of radiation pressure, and i... | evolution of the spin periods of neutron stars in low-mass x-ray binaries |
in recent years, the increasing evidence that a significant fraction of white dwarfs is accreting matter from a debris disk has triggered a significant scientific interest. its mere existence suggests that the planetary system which had formed around the star was able to survive all previous phases of stellar evolution... | the ultimate fate of planetary systems |
it is believed that low-mass stars build a significant fraction of their total mass during short outbursts of enhanced accretion (up to 10e-4 msolar /yr). the most dramatic episodic accretion events known in young stellar objects (ysos) are fu ori and exor outbursts. fu ori objects are characterized by a sudden brighte... | alma early science observations of outbursting stellar systems:disk masses for fu ori and exor objects |
we present the results of a study of the neutron star low-mass x-ray binary 4u 1636-536. we have performed temporal analysis of all available rxte/asm, rxte/pca, swift/bat and maxi data collected until 2017.we have confirmed the previously discovered quasi-periodicity of 45 d present during 2004, and we have found it c... | long-term quasi-periodicity of 4u 1636-536 resulting from accretion disc instability |
dh tau b is a planetary-mass companion orbiting the t tauri star dh tau (~0.5 solar masses) with a projected separation of 340 au. with an age of ~2 myrs, it is one of the youngest planetary-mass companions discovered to date. dh tau b straddles the deuterium-burning limit with an estimated mass of 8-22 jupiter masses,... | measuring the rotation rate of the planetary-mass companion dh tau b |
the central object in a low-mass x-ray binary (lmxb) accretes matter from its companion star mainly via roche lobe overflow; the keplerian disk, having high angular momentum and high viscosity becomes instrumental in overall accretion. in the same transient lmxb, the accumulation radius, from where matter rushes toward... | does the geometry of keperian disk vary during the outbursts of a transient lmxb? |
magnetized disk winds and wind-driven accretion are an essential and intensively studied dispersion mechanism of protoplanetary disks. however, the stability of these mechanisms has yet to be adequately examined. this paper employs semi-analytic linear perturbation theories under non-ideal magnetohydrodynamics, focusin... | non-ideal magnetohydrodynamic instabilities in protoplanetary disks: vertical modes and reflection asymmetry |
the collapse of interstellar gaseous clouds towards a protostar leads to the formation of accretion disks around the central star. such disks can be dynamically stable if they settle in an axisymmetric state. in this letter, we investigate the long-term stability of astrophysical viscous disks around various protostars... | mass limits for stationary protoplanetary accretion disks |
ringed protoplanetary disks, in the class ii phase of low-mass star formation when the envelope has mostly dispersed, have been found in abundance in recent years with high-resolution alma observations. these ringed disks have been often interpreted as evidence of ongoing planet formation. in the younger class 0 and i ... | rings in a young embedded disk: footholds of planet formation at early times |
young stars harbor a disk of gas and dust orbiting them. similarly, young planets are surrounded by a circumplanetary disk (cpd). cpds supply gas and dust to the growing planet, and they are also the birthplace of moons. if we are to understand how forming planets accrete materials, what chemical compositions accreting... | witnessing the formation of giant planets: the first discovery of a circumplanetary disk in alma molecular line observations |
we present observations and analysis of the starburst, pacs-819, at z=1.45 ($m_*=10^{10.7}$ m$_{ \odot}$), using high-resolution ($0^{\prime \prime}.1$; 0.8 kpc) alma and multi-wavelength jwst images from the cosmos-web program. dissimilar to hst/acs images in the rest-frame uv, the redder nircam and miri images reveal... | jwst and alma discern the assembly of structural and obscured components in a high-redshift starburst galaxy |
low mass x-ray binaries (lmxbs) are systems in which a compact object accretes from a binary companion star via an accretion disk. the x-ray properties of lmxbs show strong variability over timescales ranging from milliseconds to decades, much of which is tied to the extreme environment of the inner accretion disk, hen... | recurrent instability in lmxb accretion disks: how strange is grs 1915+105? |
magnetized plasma columns and extended magnetic structures with both foot points anchored to a surface layer are an important building block of astrophysical dissipation models. current loops shining in x-rays during the growth of plasma instabilities are observed in the corona of the sun and are expected to exist in h... | safety first: stability and dissipation of line-tied force-free flux tubes in magnetized coronae |
protoplanetary discs (ppds) have been widely observed around young stars and are supposed to be the birth cradle of planets. these objects are cold, dense and magnetised. among them stand the so-called transition discs (tds) characterised by a dust cavity in their inner regions, whose diameter varies from a few au to a... | magnetised winds in transition discs |
context. stellar winds of massive stars are known to be driven by line absorption of uv photons, a mechanism that is prone to instabilities, causing the wind to be clumpy. the clumpy structure hampers wind mass-loss estimates, limiting our understanding of massive star evolution. the wind structure also impacts accreti... | stellar-wind variability in cygnus x-1 from high-resolution excess variance spectroscopy with chandra |
analytical studies of black hole accretion usually presumes the stability of the stationary transonic configuration. various authors in the past several decades demonstrated the validity of such an assumption for inviscid hydrodynamic flow. inviscid approximation is a reasonable approach for low angular momentum advect... | transonic behaviour and stability analysis of quasi-viscous black hole accretion |
during the rosat and xmm-newton sky surveys a very small number of giant (factor >100), soft, x-ray flares have been seen in galactic nuclei. their very rarity shows that they are not produced by a common agn process. while they all tend to show similar decay curves, the rise and plateau sections of the flare vary c... | massive, long-duration, soft x-ray flares from galactic nuclei |
system parameters are re-determined: $m_1=0.86\pm0.18m\odot$, $m_2=0.103\pm0.022m\odot$, $a=1.508\pm 0.100\times 10^{10}$cm, and $i=69\pm3^{\circ}$. the secondary component is a semi-degenerate helium star loosing mass at a rate $\dot m=4.93\pm 1.65\times10^{-9}m\odot/yr$. the accretion disk is sufficiently hot to avoi... | am cvn -- system parameters and gravitational waves |
although during the last decade new observations and new theoretical results have brought better understanding of the physics of accretion onto compact objects, many old and several new questions and problems await answers and solutions. i show how the disc thermal-viscous instability model applied to both cataclysmic ... | problems in the astrophysics of accretion onto compact celestial bodies |
studies over the last two decades have revealed that the comoving star formation rate (sfr) and the black hole accretion rate densities have been steeply declining since z~2. tracing the evolution of the cold molecular gas which fuels star formation and black hole accretion in galaxies at intermediate redshift (0.5<... | gas dynamical imaging and dust properties of the strongly-lensed quasar host galaxy rxj1131-1231 at z~0.65 |
we show a relation of the pre- and post-nova activity of ct ser (nova 1948) and v446 her (nova 1960), known to have remarkably similar orbital periods p orb. we use both photographic and ccd photometric observations. post-nova ct ser shows a nova-like high-state activity with only a slight decrease of absolute magnitud... | relation between long-term activity and luminosity of the pre- and post-novae ct ser and v446 her |
x-ray flux and pulse period fluctuations in an accretion-powered pulsar convey important information about the disk-magnetosphere interaction. it is shown that simultaneous flux and period measurements can be analysed with a kalman filter based on the standard magnetocentrifugal accretion torque to generate accurate ti... | tracking hidden magnetospheric fluctuations in accretion-powered pulsars with a kalman filter |
the neutron star (ns) in a high mass x-ray binary (hmxb) commonly accretes from the stellar wind of its companion. observations suggest that the accretion flow around some sources (e.g. oao 1657-415) should be highly structured, which may indicate the existence of accretion disks. the ns accretion flow in a hmxb can be... | wind accretion in high mass x-ray binaries: stability and disk formation |
dwarf novae are interacting binaries in which outbursts are caused by thermal instability in the accretion disk around the white dwarf [1]. the sub-class su uma type is characterized by two types of outbursts; during a brighter and longer outburst oscillations with periods slightly exceeding the orbital (superhumps) ar... | asassn-19fy: the unusual dwarf nova in the period gap |
v1363 cyg is a cataclysmic variable (cv) and a post-nova. our analysis of its long-term optical activity used the archival data from the aavso database and literature. we showed that the accretion disk of v1363 cyg is exposed to the thermal-viscous instability (tvi) for at least part of the time. the time fraction spen... | activity of the post-nova v1363 cygni on long timescales |
a variety of astrophysical objects can launch jets: x-ray binaries, active galactic nuclei, gamma-ray bursts, and dwarf novae. jetted astrophysical systems typically possess an accretion disk, with the jet-launching compact object at the center. the radiative powers emitted by the jets and their accretion disks are hig... | magnetic field transport in accretion disk: black holes vs neutron stars |
we discuss different scenarios to explain multiple >1.5 magnitude flares in agn detected with gaia such as accretion disk instabilities, variable absorption in the line of sight, tidal disruption events, or a stellar-mass black hole — neutron star merger in the agn disc. interestingly, the rise and decay times of ~3... | peculiar agn outbursts detected by gaia |
from planets and newborn stars to the evolution of entire galaxies, many astrophysical objects grow and evolve by accumulating mass through a disc. for these objects to grow, matter must both lose angular momentum to flow inward, and avoid being removed from the system via different types of outflows. however, despite ... | binaries, accretion, and outbursts |
we consider the gravitational potential of a rotating star with non-uniform density to derive the orbital and epicyclic frequencies of the particles orbiting the star. we assume that the star is composed of concentric spheroids of constant density, with a global power-law distribution of density inside the star. at the... | epicyclic frequencies of spheroidal stars with non-uniform density |
my dissertation focuses on the effect of magnetic fields on disk and core evolution during star-formation. we investigate the fragmentation scales of gravitational instability of a rotationally-supported self-gravitating protostellar disk using linear perturbation analysis in the presence of two nonideal magnetohydrody... | the role of nonideal magnetohydrodynamic effects, gravitational instability, and episodic accretion in star-formation |
the thermal instability of accretion disks is widely used to explain the activity of cataclysmic variables, but its manifestation in gas and dust disks in young stars has been studied in less detail. a semi-analytical stationary model is presented for calculating the equatorial temperature of a gas and dust disk around... | effect of dust evaporation and thermal instability on temperature distribution in a protoplanetary disk |
spherical flows are a classic problem in astrophysics which are typically studied from a global perspective. however, much like with accretion discs, there are likely many instabilities and small scale phenomena which would be easier to study from a local perspective. for this purpose, we develop a local model for a sp... | a local model for the spherical collapse/expansion problem |
the formation of giant planets has traditionally been divided into two pathways: core accretion and gravitational instability. however, in recent years, gravitational instability has become less favored, primarily due to the scarcity of observations of fragmented protoplanetary disks around young stars and the low occu... | spirals and clumps in v960 mon: signs of planet formation via gravitational instability around an fu ori star? |
we continue studying convection as a possible factor of episodic accretion in protoplanetary disks. within the model of a viscous disk, the accretion history is analyzed at different rates and regions of matter inflow from the envelope onto the disk. it is shown that the burst-like regime occurs in a wide range of para... | long-term evolution of convectively unstable disk |
while giant planet occurrence rates increase with stellar mass, occurrence rates of close-in super-earths decrease. this is in contradiction to the expectation that the total mass of the planets in a system scale with the protoplanetary disc mass and hence the stellar mass. since the snow line plays an important role i... | formation of super-earths in icy dead zones around low-mass stars |
the disc instability mechanism (dim) is widely accepted to account for the transient behaviour of dwarf novae (dne), which experience short outbursts separated by long quiescence. the duty cycle (the ratio between the outburst duration and the recurrence time) determines the amount of accreted mass by the white dwarf (... | white dwarf mass growth in cataclysmic variables: roles of dwarf novae |
we report the detection of the disk/torus, outflow, and inflow structures traced by h2o masers toward a high-mass young stellar object w51 north during its h2o maser outburst stage using the karl g. jansky very large array (vla). it is found that the disk has a radius of ~4000 au and an inclination angle with respect t... | luminosity outburst energized by the collision between the infalling streamer and disk in w51 north |
in this paper, we investigate the astrophysical processes of stellar-mass black holes (smbhs) embedded in advection-dominated accretion flows (adafs) of supermassive black holes (smbhs) in low-luminosity active galactic nuclei. the smbh is undergoing bondi accretion at a rate lower than the smbh. outflows from the smbh... | accretion-modified stars in accretion disks of active galactic nuclei: the low-luminosity cases and an application to sgr a* |
as the number of planetary mass objects (pmos, $\lessapprox$13 m$_{\rm{jupitr}}$) at wider separation ($\gtrapprox$10 au) grows, there is emerging evidence that they form differently from their higher-mass brown-dwarf (bd) counterparts. namely, pmos' atmospheres are enriched by metals which is usually interpreted as a ... | early accretion of large amount of solids for directly-imaged exoplanets |
in current theories of planet formation, close-orbiting planets as massive as neptune are expected to be very rare around low-mass stars. we report the discovery of a neptune-mass planet orbiting the `ultracool' star lhs 3154, which is nine times less massive than the sun. the planet's orbital period is 3.7 days and it... | an extreme test case for planet formation: a close-in neptune orbiting an ultracool star |
in this paper, we try to study the fragmentation conditions of self-gravitational accretion disk in dead zone. this region is located between 1 and 5 au from the star. there is a high bump density at the outer boundary of dead zone. a bump surface density leads to the production of instability and vortices. vortices ca... | the critical cooling time for the fragmentation of accretion disks in the presence of bump density perturbation |
my dissertation focuses on the effect of magnetic fields on disk and core evolution during star-formation. we investigate the fragmentation scales of gravitational instability of a rotationally-supported self-gravitating protostellar disk using linear perturbation analysis in the presence of two nonideal magnetohydrody... | mapping the role of the magnetic fields in the partially ionized environments of magnetized interstellar clouds and disks |
young stellar objects in their pre-main sequence phase are characterized by irregular changes in brightness, generally attributed to an increase of the mass accretion rate due to various kind of instabilities occurring in the circumstellar disk. in the era of large surveys aimed to monitor the sky, we present a pipelin... | automatic detection of accretion bursts in young stellar objects: a new algorithm for long-term sky surveys |
thirty years ago it was observed that for many stars the emitted energy spectrum shows an extra bump in the infrared part. this infrared excess indicates a large gaseous disk encompassing the star. such accretion disks are regions of planet formation. understanding the mechanisms that can result in an outward angular m... | stratorotational instability in a thermally stratified taylor-couette flow |
this paper develops a unified linear theory of cross field plasma instabilities, including the farley-buneman, electron thermal, and ion thermal instabilities, in spatially uniform collisional plasmas with partially unmagnetized multi-species ions. collisional plasma instabilities in weakly ionized, highly dissipative,... | unified fluid theory of the collisional thermal farley-buneman instability including magnetized multi-species ions |
mediterranean ecosystems such as those found in california, central chile, southern europe, and southwest australia host numerous, diverse, fire-adapted micro-ecosystems. these micro-ecosystems are as diverse as mountainous conifer to desert-like chaparral communities. over the last few centuries, human intervention, i... | invasive species, extreme fire risk, and toxin release under a changing climate |
we present experiments on finite liquid volumes, hereafter referred to as blobs, of variable densities impacting an interface between two immiscible liquids at high reynolds and weber numbers. such processes occurred on a massive scale during the giant impacts that formed terrestrial planets and satellites, including t... | experiments on the impact and turbulent coalescence of a blob at a liquid-liquid interface |
the earth and space science partnership (essp) continues to collaborate with pennsylvania teachers to research how grades 4-9 students learn selected topics in earth and space science. we have previously conducted semi-structured interviews with students across a wider range of grade levels (4 - 16) to facilitate the d... | have astronomers been to neptune? results of a study of high school students' ideas about how astronomers study the solar system |
the spin, or normalized angular momentum λ, of dark matter halos in cosmological simulations follows a log normal distribution and has little correlation with galaxy observables such as stellar masses or sizes. there is currently no way to infer the λ parameter of individual halos hosting observed galaxies. here, we pr... | a first estimate of the milky way dark matter halo spin |
the large magellanic cloud (lmc) will induce a dynamical friction (df) wake on infall to the milky way (mw). the mw's stellar halo will respond to the gravity of the lmc and the dark matter (dm) wake, forming a stellar counterpart to the dm wake. this provides a novel opportunity to constrain the properties of the dm p... | structure, kinematics, and observability of the large magellanic cloud's dynamical friction wake in cold versus fuzzy dark matter |
although a variety of techniques have been employed for determining the milky way dark matter halo mass distribution, the range of allowed masses spans both light and heavy values. knowing the precise mass of our galaxy is important for placing the milky way in a cosmological λcdm context. we show that hypervelocity st... | constraining the milky way mass with hypervelocity stars |
the reflex motion and distortion of the milky way (mw) halo caused by the infall of a massive large magellanic cloud (lmc) has been demonstrated to result in an excess of orbital poles of dark matter halo particles toward the lmc orbital pole. this was suggested to help explain the observed preference of mw satellite g... | on the effect of the large magellanic cloud on the orbital poles of milky way satellite galaxies |
recent studies have suggested that the milky way (mw)'s dark matter (dm) halo may be significantly tilted with respect to its central stellar disk, a feature that might be linked to its formation history. in this work, we demonstrate a method of constraining the orientation of the minor axis of the dm halo using the an... | constraining the tilt of the milky way's dark matter halo with the sagittarius stream |
galactic rotation curves are often considered the first robust evidence for the existence of dark matter. however, even in the presence of a dark matter halo, other galactic-scale observations, such as the baryonic tully-fisher relation and the radial acceleration relation, remain challenging to explain. this has motiv... | testing dark matter and modifications to gravity using local milky way observables |
stellar streams result from the tidal disruption of satellites and star clusters as they orbit a host galaxy, and can be very sensitive probes of the gravitational potential of the host system. we select and study narrow stellar streams formed in a milky-way-like dark matter halo of the aquarius suite of cosmological s... | modeling the gravitational potential of a cosmological dark matter halo with stellar streams |
observational studies of nearby galaxies have demonstrated correlations between the mass of the central supermassive black holes (bhs) and properties of the host galaxies, notably the stellar bulge mass or central stellar velocity dispersion. motivated by these correlations, the theoretical paradigm has emerged in whic... | connecting dark matter halos with the galaxy center and the supermassive black hole |
we consider the possibility that the milky way's dark matter halo possesses a non-vanishing equation of state. consequently, we evaluate the contribution due to the speed of sound, assuming that the dark matter content of the galaxy behaves like a fluid with pressure. in particular, we model the dark matter distributio... | effects of non-vanishing dark matter pressure in the milky way galaxy |
hypervelocity stars (hvss) travel from the galactic centre across the dark matter halo of the milky way, where they are observed with velocities in excess of the galactic escape speed. because of their quasi-radial trajectories, they represent a unique probe of the still poorly constrained dark matter component of the ... | on measuring the galactic dark matter halo with hypervelocity stars |
the dark matter halos that surround milky way-like galaxies in cosmological simulations are, to first order, triaxial. nearly 30 yr ago it was predicted that such triaxial dark matter halos should exhibit steady figure rotation or tumbling motions for durations of several gigayears. the angular frequency of figure rota... | detecting the figure rotation of dark matter halos with tidal streams |
the density of dark matter near the sun, ρdm, ⊙, is important for experiments hunting for dark matter particles in the laboratory, and for constraining the local shape of the milky way's dark matter halo. estimates to date have typically assumed that the milky way's stellar disc is axisymmetric and in a steady-state. y... | estimating the local dark matter density in a non-axisymmetric wobbling disc |
aims: we present a new strong lensing mass reconstruction of the bullet cluster (1e 0657-56) at z = 0.296, based on wfc3 and acs hst imaging and vlt/fors2 spectroscopy. the strong lensing constraints underwent substantial revision compared to previously published analysis, there are now 14 (six new and eight previously... | the bullet cluster at its best: weighing stars, gas, and dark matter |
how do galaxy properties (such as stellar mass, luminosity, star formation rate, and morphology) and their evolution depend on the mass of their host dark matter halo? using the galaxy and mass assembly group catalogue, we address this question by exploring the dependence on host halo mass of the luminosity function (l... | galaxy and mass assembly: luminosity and stellar mass functions in gama groups |
using a dark matter simulation we show how halo bias is determined by local density and not by halo mass. this is not totally surprising as, according to the peak-background split model, local matter density (bar δ) is the property that constrains bias at large scales. massive haloes have a high clustering because they... | what determines large scale galaxy clustering: halo mass or local density? |
as the milky way and its satellite system become more entrenched in near field cosmology efforts, the need for an accurate mass estimate of the milky way's dark matter halo is increasingly critical. with the second and early third data releases of stellar proper motions from gaia, several groups calculated full 6d phas... | sizing from the smallest scales: the mass of the milky way |
the timing argument provides a lower limit on the mass of the milky way. using a sample of 32 stars at r > 60 kpc drawn from the h3 spectroscopic survey and mock catalogs created from published numerical simulations, we find that m200 > 0.91 × 1012 m⊙ with 90% confidence. we recommend using this limit to refine t... | a lower limit on the mass of our galaxy from the h3 survey |
employing the spherical collapse formalism, we investigate the linear evolution of the matter overdensity for energy-momentum-squared gravity (emsg), which in practical phenomenological terms one may imagine as an extension of the λ cdm model of cosmology. the underlying model, while still having a cosmological constan... | evolution of spherical overdensities in energy-momentum-squared gravity |
the dark matter halo masses of galaxies can be estimated from their stellar masses via abundance matching (am). for both the milky way and m31, the am mass is higher than the mass inferred from kinematics. the higher am masses exacerbate the missing satellite problem. the difference is especially pronounced for m31, fo... | dark matter halo masses from abundance matching and kinematics: tensions for the milky way and m31 |
the gaia map of the milky way reveals a pair of triangular features at nearly symmetric locations on opposite sides of the galactic center. in this paper we explore the implications of these features assuming they are manifestations of a caustic ring in the dark matter distribution of the milky way halo. the existence ... | implications of triangular features in the gaia skymap for the caustic ring model of the milky way halo |
we use the halo occupation distribution (hod) framework to characterize the predictions from two independent galaxy formation models for the galactic content of dark matter haloes and its evolution with redshift. our galaxy samples correspond to a range of fixed number densities defined by stellar mass and span 0 ≤ z ≤... | the evolution of the galaxy content of dark matter haloes |
aims: it is well known that the presence of baryons affects the dark matter host haloes. exploring the galaxy assembly history together with the dark matter haloes properties through time can provide a way to measure these effects.methods: we have studied the properties of four milky way mass dark matter haloes from th... | dark matter response to galaxy assembly history |
understanding the links between the activity of supermassive black holes (smbhs) at the centres of galaxies and their host dark matter haloes is a key question in modern astrophysics. the final data release of the sdss-iv eboss provides the largest contemporary spectroscopic sample of galaxies and quasi-stellar objects... | quasars at intermediate redshift are not special; but they are often satellites |
we propose a versatile and accurate method to estimate the halo mass and concentration from the kinematics of satellite galaxies. we construct the 6d phase-space distribution function of satellites from a cosmological simulation based on the similarity of internal dynamics for different halos. within the bayesian stati... | a versatile and accurate method for halo mass determination from phase-space distribution of satellite galaxies |
recent analyses of the pal 5 and gd-1 tidal streams suggest that the inner dark matter halo of the milky way is close to spherical, in tension with predictions from collisionless n-body simulations of cosmological structure formation. we use the eris simulation to test whether the combination of dissipative physics and... | around the way: testing λcdm with milky way stellar stream constraints |
we measure for the first time the outermost edges of the milky way (mw) halo in terms of the depletion and turnaround radii. the inner depletion radius, rid, identified at the location of maximum infall velocity, separates a growing halo from the draining environment, while the turnaround radius, rta, marks the outermo... | the outermost edges of the milky way halo from galaxy kinematics |
important tracers for the dark matter halo of the galaxy are hypervelocity stars (hvss), which are faster than the local escape velocity of the galaxy and their slower counterparts, the high-velocity stars in the galactic halo. such hvss are believed to be ejected from the galactic centre (gc) through tidal disruption ... | spectroscopic twin to the hypervelocity sdo star us 708 and three fast sdb stars from the hyper-muchfuss project |
the standard explanation for galaxy spin starts with the tidal-torque theory (ttt), in which an ellipsoidal dark-matter protohalo, which comes to host the galaxy, is torqued up by the tidal gravitational field around it. we discuss a complementary picture, using the relatively familiar velocity field, instead of the ti... | halo spin from primordial inner motions |
the local density of dark matter is an important quantity. on the one hand, its value is needed for dark matter direct detection searches. on the other hand, a precise and robust determination of the local dark matter density would help us learn about the shape of the dark matter halo of our galaxy, which plays an impo... | dark matter local density determination based on recent observations |
we explore constraints on the milky way dark matter halo oblateness using three stellar streams from globular clusters ngc3201, m68, and palomar 5. previous constraints on the gravitational potential from dynamical equilibrium of stellar populations and distant milky way satellites are included. we model the dark halo ... | the oblateness of the milky way dark matter halo from the stellar streams of ngc 3201, m68, and palomar 5 |
we apply noether's theorem to observations of main-sequence stars from the gaia data release 2 archive to probe the matter distribution function of the galaxy. that is, we examine the axial symmetry of stars at vertical heights z, $0.2\leqslant | z| \leqslant 3\,\mathrm{kpc}$ , to probe the quality of the angular momen... | applying noether's theorem to matter in the milky way: evidence for external perturbations and non-steady-state effects from gaia data release 2 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.