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Related papers: Estimation of the Vertical Disk Scale Height Using…

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We conduct three-dimensional hydrodynamic simulations to investigate the nonlinear outcomes and observability of vertical shear instability (VSI) in protoplanetary disks. Our models include both vertically isothermal and thermally…

Earth and Planetary Astrophysics · Physics 2024-12-16 Han-Gyeol Yun , Woong-Tae Kim , Jaehan Bae , Cheongho Han

We present the results of an SiO maser survey for color-selected IRAS sources in the area 40 < l < 70 and |b| < 10 in the SiO J=1-0, v=1 and 2 transitions. We detected 134 out of 272 observed sources in SiO masers; 127 were new detections.…

Astrophysics · Physics 2015-06-24 Jun-ichi Nakashima , Shuji Deguchi

Vertically extended, high velocity dispersion stellar distributions appear to be a ubiquitous feature of disc galaxies, and both internal and external mechanisms have been proposed to be the major driver of their formation. However, it is…

Obtaining a complete census of gas in the local interstellar medium (<100 pc) is challenging given the limited available tracers of the warm, partially-ionized medium. Medium-to-high resolution UV absorption spectroscopy toward individual…

We use two-dimensional Fourier transformation to measure the pitch angle ($\varphi$) of the dominant spiral Fourier mode of well-defined spiral arms in 13 protoplanetary disks, making use of near-infrared scattered-light images of AB Aur,…

Earth and Planetary Astrophysics · Physics 2019-06-05 Si-Yue Yu , Luis C. Ho , Zhaohuan Zhu

We completed a search for circumstellar disks around Herbig Be stars using the NRAO Very Large Array (VLA) and the IRAM Plateau de Bure (PdB) interferometers. We present our new VLA and PdBI data for the three objects MWC 297, Z CMa, and…

Astrophysics · Physics 2009-11-13 T. Alonso-Albi , A. Fuente , R. Bachiller , R. Neri , P. Planesas , L. Testi , O. Berne , C. Joblin

We gathered more than 1130 high-resolution optical spectra for more than 250 Galactic classical Cepheids. The spectra were collected with different optical spectrographs: UVES at VLT, HARPS at 3.6m, FEROS at 2.2m MPG/ESO, and STELLA. To…

We report the discovery of nineteen new HI shells in the Southern Galactic Plane Survey (SGPS). These shells, which range in radius from 40 pc to 1 kpc, were found in the low resolution Parkes portion of the SGPS dataset, covering Galactic…

Astrophysics · Physics 2009-11-07 N. M. McClure-Griffiths , John M. Dickey , B. M. Gaensler , A. J. Green

The disk masses of four low surface brightness galaxies (LSB) were estimated using marginal gravitational stability criterion and the stellar velocity dispersion data which were taken from Pizzella et al., 2008 [1]. The constructed mass…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 A. S. Saburova

We present the results of a multi-wavelength multi-epoch survey of five evolved protoplanetary disks in the IC 348 cluster that show significant infrared variability. Using 3-8micron and 24micron photometry along with 5-40micron…

Astrophysics of Galaxies · Physics 2015-06-04 Kevin Flaherty , James Muzerolle , George Rieke , Robert Gutermuth , Zoltan Balog , William Herbst , S. T. Megeath , Maria Kun

This study aims to characterize debris disks observed with SPHERE across multiple programs, with the goal of identifying systematic trends in disk morphology, dust mass, and grain properties as a function of stellar parameters. We analyzed…

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…

Earth and Planetary Astrophysics · Physics 2015-06-18 Jonathan P. Williams , William M. J. Best

High-angular resolution observations at sub-millimeter/millimeter wavelengths of disks surrounding young stars have shown that their morphology is made of azimuthally-symmetric or point-symmetric substructures, in some cases with spiral…

Earth and Planetary Astrophysics · Physics 2021-10-27 Diana Blanco , Luca Ricci , Mario Flock , Neal Turner

I present detailed models for the formation of disk galaxies, and investigate which observables are best suited as virial mass estimators. Contrary to naive expectations, the luminosities and circular velocities of disk galaxies are…

Astrophysics · Physics 2009-11-07 Frank C. van den Bosch

Dynamical estimates of the mass surface density at the solar radius can be made up to a height of 4 kpc using thick disk stars as tracers of the potential. We investigate why different Jeans estimators of the local surface density lead to…

Astrophysics of Galaxies · Physics 2016-01-27 F. J. Sanchez-Salcedo , C. Flynn , J. A. de Diego

The distribution of metals within a galaxy traces the baryon cycle and the buildup of galactic disks, but the detailed gas phase metallicity distribution remains poorly sampled. We have determined the gas phase oxygen abundances for 7,138…

Several thin, Keplerian, sub-parsec megamaser disks have been discovered in the nuclei of active galaxies and used to precisely determine the mass of their host black holes. We show that there is an empirical linear correlation between the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Mark Wardle , Farhad Yusef-Zadeh

We present results of a ground-based survey for Cepheid variables in NGC 4258. This galaxy plays a key role in the Extragalactic Distance Scale due to its very precise and accurate distance determination via VLBI observations of water…

Solar and Stellar Astrophysics · Physics 2015-05-27 Samantha L. Hoffmann , Lucas M. Macri

The clumpy maser disks observed in some galactic nuclei mark the outskirts of the accretion disk that fuels the central black hole and provide a potential site of nuclear star formation. Unfortunately, most of the gas in maser disks is…

Astrophysics · Physics 2009-06-23 Abraham Loeb

In an effort to improve our understanding of the spiral arm structure of the Milky Way, we use Classical Cepheids (CCs) to increase the number of young tracers on the far side of the Galactic disk with accurately determined distances. We…