相关论文: Pixel and Micro-lensing with NGST
The robustness of stellar-dynamical black hole (BH) mass measurements is illustrated using 7 galaxies that have results from independent groups. Derived masses have remained constant to a factor of about 2 as spatial resolution has improved…
The presence of brown dwarfs in the dark galactic halo could be detected through their gravitational lensing effect and experiments under way monitor about one million stars to observe a few lensing events per year. We show that if the…
We study different models of dark matter distribution for the halo of our galaxy. In particular, we consider Eddington and King-Michie models, which [C[C, which include anisotropy in the velocity space, and compute in a self-consistent way…
Gravitational lensing of background compact objects like active galactic nuclei and quasars, by extended intermediate mass lenses such as globular clusters and and dark matter clumps with masses 10^5 - 10^8 M_sun, is considered. It is shown…
Highly magnified stars ($\mu$ $>$ 100) are now outinely identified as transient events at cosmological distances thanks to microlensing by intra-cluster stars near the critical curves of galaxy clusters. Using the {\it James Webb} Space…
The optical depth to microlensing toward M31 due to known stars in the disk of M31 itself is $\tau\sim 2\times 10^{-7}e^{-r/d}$ where $d$ is the disk scale length and $r$ is the distance along the major axis. Thus, there can be significant…
In the standard structure formation scenario based on the cold dark matter paradigm, galactic halos are predicted to contain a large population of dark matter subhalos. While the most massive members of the subhalo population can appear as…
This is a personal review of various issues related to massive photometric and astrometric searches. A complete inventory of variable stars down to almost any magnitude limit will improve our understanding of the stellar evolution and the…
We use galaxy-galaxy lensing to investigate how the dark matter (DM) haloes and stellar content of galaxies with $0.012 \leq z \leq 0.32$ and $10 \leq \log_{10}(M_\star/\mathrm{M}_\odot) \leq 12$ change as a result of the merger process. To…
The Pan-STARRS 1 (PS1) survey of M31 (PAndromeda) is designed to identify gravitational microlensing events, caused by bulge and disk stars (self-lensing) and by compact matter in the halos of M31 and the Milky Way (halo lensing, or lensing…
The ages and metallicities of globular clusters play an important role not just in testing models for their formation and evolution but in understanding the assembly history for their host galaxies. Here we use a combination of imaging and…
Gravitational lensing is an important prediction of general relativity, providing both its test and a tool to detect faint but amplified sources and to measure masses of lenses. For some applications (e.g. testing the theory), a point…
The last decade has shown a considerable development of gravitational lensing for cosmology because it probes the amount and the nature of dark matter, and provides information on the density parameter $\Omega$, the cosmological constant…
The gravitational lensing of supermassive black holes surrounded by dark matter halo has attracted a great number of interests in recent years. However, many studies employed simplified dark matter density models, which makes it very hard…
Experimental developments in neutrino telescopes are drastically improving their ability to constrain the annihilation cross-section of dark matter. In this paper, we employ an angular power spectrum analysis method to probe the galactic…
Microlensing studies of quasars can reveal dark matter lumps over a broad mass spectrum; we highlight the importance of monitoring quasars which are seen through the halos of low-redshift galaxies. For these configurations microlensing by…
We have carried out a survey of the Andromeda galaxy for unresolved microlensing (pixel lensing). We present a subset of four short timescale, high signal-to-noise microlensing candidates found by imposing severe selection criteria: the…
Gravitational microlensing provides a unique technique to reveal information about extragalactic planets. A network of at least four 2m-class telescopes distributed around the northern hemisphere could probe 15-35 jupiters and 4-10 saturns…
We consider strong gravitational lensing by nearby stars. Using our wave-optical treatment of lensing phenomena, we study Einstein rings that may form around nearby stellar lenses. It is remarkable that these rings are bright and large…
Quadruple gravitational lens systems offer the possibility of measuring time delays for image pairs, microlensing effects, and extinction in distant galaxies. Observations of these systems may be used to obtain estimates of H_o and to study…