相关论文: Enhancing the H2O Megamaser Detection Rate Using O…

Water megamasers at 22 GHz with a gas disk configuration in galaxies provide the most precise measurements of supermassive black hole masses, as well as independent constraints on the Hubble constant in the nearby universe. The existence of…

We present a new investigation of the dependence of H2O maser detection rates and properties on the mid-IR AGN luminosity, L_AGN, and the obscuring column density, N_H, based on mid-IR and hard X-ray photometry. Based on spectral energy…

Water megamaser emission at 22 GHz has proven to be a powerful tool for astrophysical studies of AGN allowing an accurate determination of the central black hole mass and of the accretion disc geometry and dynamics. However, after searches…

Extragalactic water maser emissions at 22 GHz have been playing vital roles in astrophysics. The limited detection rate of these masers has been motivating researchers to find clues that can help characterise them. The physical environments…

We study the optical properties of the host galaxies of nuclear 22 GHz (lambda=1.35 cm) water masers. To do so, we cross-match the galaxy sample surveyed for water maser emission (123 detections and 3806 non-detections) with the SDSS…

We report four new 22 GHz water masers found in a Green Bank Telescope search toward 37 nearby objects. Our goal was to find new maser galaxies, AGN disk-masers, and objects where both hydroxyl and water maser species coexist. We observed…

High precision estimation of the equation of state of dark energy depends on constraints external to analyses of Cosmic Microwave Background fluctuations. A geometric estimation of the local expansion rate, H_o, would provide the most…

We describe a method to identify inclined water maser disks orbiting massive black holes and to potentially use them to measure black hole masses. Due to the geometry of maser amplification pathways, the minority of water maser disks are…

In combination with observations of the Cosmic Microwave Background, a measurement of the Hubble Constant provides a direct test of the standard $\Lambda$CDM cosmological model and a powerful constraint on the equation of state of dark…

We report the detection of water maser emission from four nearby galaxies hosting ultradense HII (UDHII) regions, He 2-10, the Antennae galaxies (NGC 4038/4039), NGC 4214, and NGC 5253, with the Green Bank Telescope. Our detection rate is…

We present single-dish monitoring of the spectra of 13 extragalactic water megamasers taken over a period of 9 years and a single epoch of sensitive spectra for 7 others. Our data include the first K-band science observations taken with the…

We report a search for H2O megamasers in 274 SDSS type-2 AGNs (0.3 < z < 0.83), half of which can be classified as type-2 QSOs from their [OIII] 5007 luminosity, using the Robert C. Byrd Green Bank Telescope (GBT) and the Effelsberg 100-m…

The Galactic Center contains large amounts of molecular and ionized gas as well as a plethora of energetic objects. Water masers are an extinction-insensitive probe for star formation and thus ideal for studies of star formation stages in…

A sample of nearby galaxies hosting low-luminosity type 1 quasi-stellar objects (QSOs), previously studied in CO and HI emission lines, has been searched for maser emission. Using the Effelsberg 100-m telescope, we observed 17 sources with…

Using the Green Bank Telescope, we conducted a ``snapshot'' survey for water maser emission toward the nuclei of 611 galaxies and detected eight new sources. The sample consisted of nearby (v < 5000 km/s) and luminous (M_B < -19.5)…

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.…

Questions surround the connection of luminous extragalactic masers to galactic processes. The observation that water and hydroxyl megamasers rarely coexist in the same galaxy has given rise to a hypothesis that the two species appear in…

Very luminous extragalactic water masers, the megamasers, are associated with active galactic nuclei (AGN) in galaxies characterized by accretion disks, radio jets, and nuclear outflows. Weaker masers, the kilomasers, seem to be mostly…

Investigations of H$_2$O maser galaxies at X-ray energies reveal that most AGN associated with water masers are characterized by high levels of absorption. With the aim of finding new maser sources for possible interferometric follow-ups,…

High-resolution observations of the central few 100 pc of the galactic nuclear environments remain prohibitive for large statistical samples, which are crucial for tracing the links between central black hole formation, galaxy formation and…