Zobrazeno 1 - 10
of 276
pro vyhledávání: '"Ortwin Gerhard"'
Autor:
Behzad Tahmasebzadeh, Shashank Dattathri, Monica Valluri, Juntai Shen, Ling Zhu, Vance Wheeler, Ortwin Gerhard, Sandeep Kumar Kataria, Leandro Beraldo e Silva, Kathryne J. Daniel
Publikováno v:
The Astrophysical Journal, Vol 975, Iss 1, p 120 (2024)
Barred galaxies exhibit boxy/peanut or X-shapes (BP/X) protruding from their disks in edge-on views. Two types of BP/X morphologies exist depending on whether the X-wings meet at the center (CX) or are off-centered (OX). Orbital studies indicate that
Externí odkaz:
https://doaj.org/article/6bcbc12829a9492997078cb346d9e3d0
Autor:
Zi-Xuan Feng, Zhi Li, Juntai Shen, Ortwin Gerhard, R. P. Saglia, Matias Blaña, Hui Li, Yingjie Jing
Publikováno v:
The Astrophysical Journal, Vol 963, Iss 1, p 22 (2024)
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 simulation
Externí odkaz:
https://doaj.org/article/877fd18e3f884a5d861c7520dccbd450
Publikováno v:
The Astrophysical Journal Letters, Vol 956, Iss 1, p L14 (2023)
An outstanding question is whether the α /Fe bimodality exists in disk galaxies other than in the Milky Way. Here we present a bimodality using our state-of-the-art galactic chemical evolution models that can explain various observations in the Andr
Externí odkaz:
https://doaj.org/article/cf36960b1a764b488b095fb4c9bc8d2d
Autor:
Magda Arnaboldi, Ortwin Gerhard
Publikováno v:
Frontiers in Astronomy and Space Sciences, Vol 9 (2022)
Nearly all intragroup (IGL) and intracluster light (ICL) comes from stars that are not bound to any single galaxy but were formed in galaxies and later unbound from them. In this review we focus on the physical properties–phase space properties, me
Externí odkaz:
https://doaj.org/article/a021944c30a042788969aa32a33eb605
Publikováno v:
Galaxies, Vol 3, Iss 4, Pp 212-219 (2015)
Planetary nebulas (PNs) offer a unique tool to investigate the outer regions of massive galaxies because their strong [OIII]λ5007Å emission line makes them detectable out to several effective radii from the galaxy’s centre. We use a deep and exte
Externí odkaz:
https://doaj.org/article/889df2b4e9264239a13f8faa75fe2903
Autor:
Jonathan P Clarke, Ortwin Gerhard
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 512:2171-2188
We compare distance resolved, absolute proper motions in the Milky Way bar/bulge region to a grid of made-to-measure dynamical models with well defined pattern speeds. The data are obtained by combining the relative VVV Infrared Astrometric Catalog v
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::60c8d05baf143dccc45d75cf1b6123f7
https://doi.org/10.1093/mnras/stac603
https://doi.org/10.1093/mnras/stac603
Autor:
Michael R. Merrifield, Anastasia A. Ponomareva, Magda Arnaboldi, Konrad Kuijken, Kenneth C. Freeman, Suryashree Aniyan, Ortwin Gerhard, Lodovico Coccato
Publikováno v:
Monthly Notices of the Royal Astronomical Society, 500(3), 3579-3593. Oxford University Press
Monthly Notices of the Royal Astronomical Society, 500(3), 3579-3593
Monthly Notices of the Royal Astronomical Society, 500(3), 3579-3593
The mass-to-light ratio (M/L) is a key parameter in decomposing galactic rotation curves into contributions from the baryonic components and the dark halo of a galaxy. One direct observational method to determine the disc M/L is by calculating the su
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b7f2ddb401af5d32329c4742d46aaadc
https://ui.adsabs.harvard.edu/abs/2021MNRAS.500.3579A
https://ui.adsabs.harvard.edu/abs/2021MNRAS.500.3579A
Autor:
Souradeep Bhattacharya, Magda Arnaboldi, Nelson Caldwell, Ortwin Gerhard, Chiaki Kobayashi, Johanna Hartke, Kenneth C Freeman, Alan W McConnachie, Puragra Guhathakurta
We obtain a magnitude-limited sample of Andromeda (M 31) disc PNe with chemical abundance estimated through the direct detection of the [OIII] 4363 $\mathring{\mathrm A}$ line. This leads to $205$ and $200$ PNe with oxygen and argon abundances respec
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::732a16c9fbb6dac1db1d4570b2874883
http://arxiv.org/abs/2203.06428
http://arxiv.org/abs/2203.06428
The formation and evolutionary history of M31 are closely related to its dynamical structures, which remain unclear due to its high inclination. Gas kinematics could provide crucial evidence for the existence of a rotating bar in M31. Using the posit
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::907ae26933dba418f6a3d78852908b83
Publikováno v:
MNRAS
We present an analytic model of the stellar mass distribution of the Milky Way bar. The model is obtained by fitting a multi-component parametric density distribution to a made-to-measure N-body model of Portail et al., constructed to match a variety
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::58b16533d5289345aaf0ab0adf2138aa