Related papers: NG7538 IRS1 N: modeling a circumstellar maser disk

We present the first astronomical detection of the 14NH3 (J,K) = (10,6) line: nonthermal emission at several velocities in the Galactic star-forming region NGC 7538. Using the VLA we have imaged the (10,6) and (9,6) ammonia masers at…

We report the detection of a massive rotating disk around the high-mass Class 0 candidate NGC 7538S. The disk is well-resolved with BIMA (HPBW =3.7") in 3.4 mm continuum and in H13CN J = 1 - 0. It is seen nearly edge on and has a size of ~…

The nearby spiral galaxy NGC 7331 was spectrally mapped from 5-38um using all modules of Spitzer's IRS spectrograph. A strong new dust emission feature, presumed due to PAHs, was discovered at 17.1um. The feature's intensity is nearly half…

We present a Submillimeter Array study in the 1.3 mm waveband of the NGC 7538 IRS 1--3 massive star-forming region. The brightest core in the mm continuum map, MM1, harbors the IRS 1 young O star. The core has a gas temperature of about 245…

Characterizing rotation, infall and accretion disks around high-mass protostars is an important topic in massive star formation research. With the Australia Telescope Compact Array and the Very Large Array we studied a massive disk…

We report the result of an on-going survey for 22 GHz H2O maser emission towards infrared luminous galaxies. The observed galaxies were selected primarily from the IRAS bright galaxy sample. The survey has resulted in the detection of one…

We report detection of moderate to high-mass star formation in an infrared dark cloud (G11.11-0.12) where we discovered class II methanol and water maser emissions at 6.7 GHz and 22.2 GHz, respectively. We also observed the object in…

A wealth of new information about the structure of the maser disk in NGC 4258 has been obtained from a series of 18 VLBA observations spanning three years, as well as from 32 additional epochs of spectral monitoring data from 1994 to the…

The Australia Telescope Compact Array (ATCA) has been used to image class I methanol masers at 9.9, 25 (a series from J=2 to J=9), 84, 95 and 104 GHz located in the vicinity of IRAS 16547-4247 (G343.12-0.06), a luminous young stellar object…

The structure and kinematics of Class 0 protostars on scales of a few hundred AU is poorly known. Recent observations have revealed the presence of Keplerian disks with a diameter of 150-180 AU in L1527-IRS and VLA1623A, but it is not clear…

Ring-like distributions of the 6.7 GHz methanol maser spots at milliarcsecond scales represent a family of molecular structures of unknown origin associated with high-mass young stellar objects (HMYSOs). We aim to study G23.657-00.127,…

We investigate the structure and kinematics of the circumstellar disk around the Herbig Ae star MWC 758 using high resolution observations of the 12CO (3-2) and dust continuum emission at the wavelengths of 0.87 and 3.3 mm. We find that the…

We present deep high angular resolution observations of the high-mass protostar NGC 7538S, which is in the center of a cold dense cloud core with a radius of 0.5 pc and a mass of ~2,000 Msun. These observations show that NGC 7538S is…

We wish to investigate the structure, velocity field, and stellar content of the G16.59-0.05 high-mass star-forming region, where previous studies have established the presence of two almost perpendicular (NE-SW and SE-NW), massive…

We present a new XMM-Newton spectrum of the Seyfert 2 nucleus of IC 2560, which hosts H$_{2}$O maser emission from an inclined Keplerian accretion disk. The X-ray spectrum shows soft excess due to multi-temperature ionized plasma, a hard…

We determine the distribution of circumstellar disk masses in the young (~0.3 Myr) cluster NGC 2024 by imaging a 2.5'x2.5' region in 3mm continuum emission to an RMS noise level of ~0.75 mJy/beam with the Owens Valley Millimeter Array. The…

We present multi-wavelengths observations and a radiative transfer model of a newly discovered massive circumstellar disk of gas and dust which is one of the largest disks known today. Seen almost edge-on, the disk is resolved in…

We present high resolution Na I D spectroscopy of the beta Pic disk, and the resonantly scattered sodium emission can be traced from less than 30 AU to at least 140 AU from the central star. This atomic gas is co-existent with the dust…

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.…

H$_2$O MegaMaser emission may arise from thin gas discs surrounding the massive nuclei of galaxies such as NGC\,4258, but the physical conditions responsible for the amplified emission are unclear. A detailed view of these regions is…