Related papers: Mrk 1419 - a new distance determination

The disks that surround young stars are mostly composed of molecular gas, which is harder to detect and interpret than the accompanying dust. Disk mass measurements have therefore relied on large and uncertain extrapolations from the dust…

Water masers are good tracers of high-mass star-forming regions. Water maser VLBI observations provide a good probe to study high-mass star formation and the galactic structure. We plan to make a blind survey toward the northern Galactic…

Since the IAU (maser-)Symposium 287 in Stellenbosch/South Africa (Jan. 2012), great progress has been achieved in studying extragalactic maser sources. Sensitivity has reached a level allowing for dedicated maser surveys of extragalactic…

H$_2$O megamasers residing in the accretion disks of active galactic nuclei (AGN) exhibit Keplerian rotation about the central supermassive black hole (SMBH). Such disk maser systems are excellent tools for diagnosing the kinematic status…

Accurate distances are fundamental to interpreting many measured properties of galaxies. Surprisingly, many of the best-studied spiral galaxies in the Local Volume have distance uncertainties that are much larger than can be achieved with…

Near-future surveys promise a dramatic improvement in the number and precision of astrometric, photometric and spectroscopic measurements of stars in the Milky Way's disk. We examine the impact of such surveys on our understanding of the…

VLBA and EVN radio observations of H2O masers at 22 GHz and methanol masers at 6.7 GHz have been used to obtain images of the maser spots in the infrared object GL2789, which is associated with the young stellar object V645Cyg. The position…

We present 3D velocity measurements and acceleration limits for stars within a few parsec of the Galactic Center (GC) black hole, Sgr A*, based on observations of 43 and 86 GHz circumstellar maser emission. Observations were taken with the…

Context: Maser emission from the H2O molecule probes the warm, inner circumstellar envelopes of oxygen-rich red giant and supergiant stars. Multi-maser transition studies can be used to put constraints on the density and temperature of the…

The parameters of the Galactic spiral wave are re-determined using a modified periodogram (spectral) analysis of the galactocentric radial velocities of 58 masers with known trigonometric parallaxes, proper motions, and line-of-site…

We have conducted multi-epoch EVN observations of the 22.2 GHz water masers towards the high-mass young stellar object in AFGL 5142. With four observing epochs, spanning a time of ~1 year, 12 distinct maser features have been detected, 7…

Debris disks are exoplanetary systems that contain planets, minor bodies (i.e., asteroids, Kuiper belt objects, comets, etc.), and micron-sized debris dust. Since water ice is the most common frozen volatile, it plays an essential role in…

We report the discovery of H2O maser emission at 1.35 cm wavelength in seven active galactic nuclei (at distances up to <80 Mpc) during a survey conducted at the 70-m diameter antenna of the NASA Deep Space Network near Canberra, Australia.…

The NGC 1333 IRAS 4 region was observed in the 22 GHz H2O maser line with an angular resolution of about 0.08 arcseconds. Two groups of masers were detected, one near IRAS 4A and the other near BI. Among the eight maser spots detected near…

We have developed a new technique called Direct Shear Mapping (DSM) to measure gravitational lensing shear directly from observations of a single background source. The technique assumes the velocity map of an un-lensed, stably-rotating…

The Square Kilometre Array (SKA) is the radio telescope of the next generation, providing an increase in sensitivity and angular resolution of two orders of magnitude over existing telescopes. Currently, the SKA is expected to span the…

We use the clump giants of the disk as standard candles calibrated from Hipparcos parallaxes in order to map their distribution with two new near-IR surveys of the Galactic plane: UKIDSS-GPS and VVV. We explore different selection cuts of…

In the era of precision cosmology it is essential to determine the Hubble Constant with an accuracy of 3% or better. Currently, its uncertainty is dominated by the uncertainty in the distance to the Large Magellanic Cloud (LMC) which as the…

Peculiar velocities of clusters of galaxies can be measured by studying the fluctuations in the cosmic microwave background (CMB) generated by the scattering of the microwave photons by the hot X-ray emitting gas inside clusters. While for…

Distances to high mass star forming regions (HMSFRs) in the Milky Way are a crucial constraint on the structure of the Galaxy. Only kinematic distances are available for a majority of the HMSFRs in the Milky Way. Here we compare the…