Related papers: Gravitational redshift in the NGC 4258 disk?

We report on our ongoing, high-resolution study of H2O masers in the innermost parsec of NGC 4258. Over thirty epochs of VLBA and VLA data, taken over six years, are being used to monitor the velocities, accelerations, positions and proper…

In this paper we demonstrate the possibility of inferring the presence of Keplerian gaseous disks using optical ground-based telescopes properly equipped. We have modeled the peculiar bidimensional shape of the emission lines in a sample of…

We present the results of very long baseline interferometry (VLBI) observations of water vapor masers in the nucleus of the LINER galaxy NGC 7738. The red- and blue-shifted and newly detected systemic maser features show an almost edge-on…

Spatial and kinematical correlations between HI and CO (2-1) emission of the southern spiral galaxy NGC4945 are studied with a common angular (23 arcsec) and velocity resolution (7 km/s). The 21cm continuum emission is also observed. The HI…

After correcting spherical aberration in the Hubble Space Telescope in 1993, the central masses of galaxies can be measured with a resolution 5 to 10 times better than can be achieved at the best terrestrial sites. This improvement in…

We present new Space Telescope Imaging Spectrograph (STIS) observations of three spiral galaxies, NGC 4303, NGC 3310 and NGC 4258. The bright optical emission lines H$\alpha$ $\lambda$ $6564 \AA$, [NII] $\lambda$$\lambda$ $6549,6585 \AA$…

We discuss Hubble Space Telescope optical images and spectra of NGC 6251, a giant E2 galaxy and powerful radio source at a distance of 106 Mpc (for H_0 = 70 km/s/Mpc). The galaxy is known to host a very well defined dust disk (O'Neil et al.…

For some neutron stars (NSs) in the binary systems, the masses have been accurately measured. While for the isolated neutron stars (INSs), no mass measurement has been reported yet. The situation will change soon thanks to the successful…

The distribution of masses of neutron stars, particularly the maximum mass value, is considered a probe of their formation, evolution and internal physics (i.e., equation of state). This mass distribution could in principle be inferred from…

A quantitative spectroscopic study of blue supergiant stars in the Hubble constant anchor galaxy NGC 4258 is presented. The non-LTE analysis of Keck I telescope LRIS spectra yields a central logarithmic metallicity (in units of the solar…

An iterative method for reconstructing mass distribution in spiral galaxies using a thin disk approximation is developed. As an example, the method is applied to galaxy NGC 4736; its rotation curve does not allow one to employ a model with…

We present the results of a search for molecular gas emission from a star-forming galaxy at z = 4.9. The galaxy benefits from magnification of 22 +/- 5x due to strong gravitational lensing by the foreground cluster MS1358+62. We target the…

We predict the amplitude of the gravitational redshift of galaxies in galaxy clusters using an N-body simulation of a Lambda CDM universe. We examine if it might be possible to detect the gravitational effect on the total redshift observed…

We present the results of a search for the nature of ultraluminous X-ray source (ULX) X-3 in the nearby galaxy NGC 4258. We use archival data from {\it XMM-Newton}, {\it Chandra}, {\it NuSTAR} and {\it HST} observations. Total X-ray data…

We derive the empirical formulae expressing the mass and gravitational redshift of a neutron star, whose central density is less than threefold the nuclear saturation density, as a function of the neutron-skin thickness or the dipole…

We present HST/STIS spectra of the Sbc spiral galaxy NGC 4041 which were used to map the velocity field of the gas in its nuclear region. We detect the presence of a compact (r~0.4" ~40 pc), high surface brightness, rotating nuclear disk…

We have analyzed the total and nuclear SED for NGC 4261 and find that the dominant process for the mid- and far-infrared emission in this object is non-thermal emission from the active nucleus. Modeling the emission from the optically…

It is shown that the matter concentration observed through stellar motion at the galactic center (Eckart & Genzel, 1997, MNRAS, 284, 576 and Genzel et al., 1996, ApJ, 472, 153) is consistent with a supermassive object of $2.5 \times 10^6$…

We aim to explore the relationship between globular cluster total number, $N_{\rm GC}$, and central black hole mass, $M_\bullet$, in spiral galaxies, and compare it with that recently reported for ellipticals. We present results for the Sbc…

We present $\sim0.10^{\prime\prime}-$resolution Atacama Large Millimeter/submillimeter Array (ALMA) CO(2$-$1) imaging of the arcsecond-scale ($r \approx 150$ pc) dusty molecular disk in the giant elliptical galaxy NGC 3258. The data provide…