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Related papers: On the Galactic Spiral Patterns: Stellar and Gaseo…

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Direct measurements of cosmic ray (CR) species combined with observations of their associated gamma-ray emissions can be used to constrain models of CR propagation, trace the structure of the Galaxy, and search for signatures of new…

High Energy Astrophysical Phenomena · Physics 2018-04-11 Gudlaugur Johannesson , Troy A. Porter , Igor V. Moskalenko

Spiral arms are common features in low-redshift disc galaxies, and are prominent sites of star-formation and dust obscuration. However, spiral structure can take many forms: from galaxies displaying two strong `grand design' arms, to those…

Astrophysics of Galaxies · Physics 2017-04-19 Ross E. Hart , Steven P. Bamford , Kevin R. V Casteels , Sandor J. Kruk , Chris J. Lintott , Karen L. Masters

We analyzed ionized gas motion and disk orientation parameters for 15 spiral galaxies. Their velocity fields were measured with the H-alpha emission line by using the Fabry-Perot interferometer at the 6m telescope of SAO RAS. Special…

Observational data indicate that the Milky Way is a barred spiral galaxy. Computation facilities and availability of data from Galactic surveys stimulate the appearance of models of the Galactic structure. More efforts to build dynamical…

Astrophysics of Galaxies · Physics 2018-07-18 Tatiana A. Michtchenko , Jacques R. D. Lépine , Douglas A. Barros , Ronaldo S. S. Vieira

The arm structure of the Milky Way remains somewhat of an unknown, with observational studies hindered by our location within the Galactic disc. In the work presented here we use smoothed particle hydrodynamics (SPH) and radiative transfer…

Astrophysics of Galaxies · Physics 2015-06-24 Alex R. Pettitt , Clare L. Dobbs , David M. Acreman , Matthew R. Bate

The mass distribution of the Galactic disk is constructed from the terminal velocity curve and the mass discrepancy-acceleration relation. Mass models numerically quantifying the detailed surface density profiles are tabulated. For $R_0 =…

Astrophysics of Galaxies · Physics 2016-01-13 Stacy S. McGaugh

The mean Galactocentric radial velocities $\langle v_{R}\rangle(R,\varphi)$ of luminous red giant stars within the mid-plane of the Milky Way reveal a spiral signature, which could plausibly reflect the response to a non-axisymmetric…

We determine the spatial distribution function of galaxies from a wide range of samples in the 2MASS survey. The results agree very well with the form of the distribution predicted by the theory of cosmological gravitational many-body…

Astrophysics · Physics 2009-11-10 Gregory R. Sivakoff , William C. Saslaw

The spiral structure of our Milky Way Galaxy is not yet known. HII regions and giant molecular clouds are the most prominent spiral tracers. We collected the spiral tracer data of our Milky Way from the literature, namely, HII regions and…

Astrophysics of Galaxies · Physics 2015-05-13 L. G. Hou , J. L. Han , W. B. Shi

We present the MATLAB code Spirality, a novel method for measuring spiral arm pitch angles by fitting galaxy images to spiral templates of known pitch. Computation time is typically on the order of 2 minutes per galaxy, assuming at least 8…

Context: In spiral galaxies, star formation tends to trace features of the spiral pattern, including arms, spurs, feathers, and branches. However, in our own Milky Way, it has been challenging to connect individual star-forming regions to…

We present trigonometric parallax and proper motion measurements toward 22 GHz water and 6.7 GHz methanol masers in 16 high-mass star-forming regions. These sources are all located in the Scutum spiral arm of the Milky Way. The observations…

Astrophysics of Galaxies · Physics 2020-01-08 K. Immer , J. Li , L. H. Quiroga-Nuñez , M. J. Reid , B. Zhang , L. Moscadelli , K. L. J. Rygl

The Milky Way spiral arm dynamics is studied using the birth place of open clusters. We separately study the nearby spiral arms, and find evidence for multiple spiral sets. In particular, the Sagittarius-Carina arm appears to be a…

Astrophysics · Physics 2016-08-30 Smadar Naoz , Nir J. Shaviv

Using far-infrared 240 micron and near-infrared K band data from the COBE/DIRBE instrument, we model the Galactic stellar and dust distribution. Making the assumption that the Galaxy is transparent in the 240 micron band, the dust emission…

Astrophysics · Physics 2007-05-23 Ronald Drimmel , David Spergel

We examined offsets between HII regions and molecular clouds belonging to spiral arms of a late type spiral galaxy NGC 4254 (M99). We used a high resolution CO(1-0) image obtained by Nobeyama Millimeter Array (NMA) and an H-alpha image. We…

Astrophysics · Physics 2015-06-24 Fumi Egusa , Yoshiaki Sofue , Hiroyuki Nakanishi

Using N-body simulations of the Milky Way interacting with a satellite similar to the Sagittarius dwarf galaxy, we quantitatively analyse the vertical response of the Galactic disc to the satellite's repeated impacts. We approximate the…

The large-scale gaseous shocks in the bulge of M31 can be naturally explained by a rotating stellar bar. We use gas dynamical models to provide an independent measurement of the bar pattern speed in M31. The gravitational potentials of our…

Astrophysics of Galaxies · Physics 2023-11-14 Zi-Xuan Feng , Zhi Li , Juntai Shen , Ortwin Gerhard , Roberto Saglia , Matias Blana , Hui Li , Yingjie Jing

In 2018, the ESA \Gaia\ satellite discovered a remarkable spiral pattern ("phase spiral") in the $z-V_z$ phase plane throughout the solar neighbourhood, where $z$ and $V_z$ are the displacement and velocity of a star perpendicular to the…

Astrophysics of Galaxies · Physics 2021-03-17 Joss Bland-Hawthorn , Thor Tepper-Garcia

We compare the observed radial velocity of different arm tracers, taken near the tangent to a spiral arm. A slight difference is predicted by the density wave theory, given the shock predicted at the entrance to the inner spiral arm. In…

Astrophysics of Galaxies · Physics 2023-01-06 Jacques P Vallée

(abridged) We investigate the detailed response of gas to the formation of transient and long-lived dynamical structures induced in the early stages of a disk-disk collision, and identify observational signatures of radial gas inflow…

Astrophysics · Physics 2009-11-10 Daisuke Iono , Min S. Yun , J. Christopher Mihos