Mostrar el registro sencillo del ítem
dc.contributor.author
Richter, Philipp
dc.contributor.author
Nuza, Sebastian Ernesto
![Se ha confirmado la validez de este valor de autoridad por un usuario](/themes/CONICETDigital/images/authority_control/invisible.gif)
dc.contributor.author
Fox, A. J.
dc.contributor.author
Wakker, B. P.
dc.contributor.author
Lehner, N.
dc.contributor.author
Ben Bekhti, N.
dc.date.available
2019-12-19T13:24:23Z
dc.date.issued
2017-06
dc.identifier.citation
Richter, Philipp; Nuza, Sebastian Ernesto; Fox, A. J.; Wakker, B. P.; Lehner, N.; et al.; An HST/COS legacy survey of high-velocity ultraviolet absorption in the Milky Way's circumgalactic medium and the Local Group; EDP Sciences; Astronomy and Astrophysics; 607; A48; 6-2017; 1-37
dc.identifier.issn
0004-6361
dc.identifier.uri
http://hdl.handle.net/11336/92530
dc.description.abstract
Context. The Milky Way is surrounded by large amounts of diffuse gaseous matter that connects the stellar body of our Galaxy with its large-scale Local Group (LG) environment. Aims. To characterize the absorption properties of this circumgalactic medium (CGM) and its relation to the LG we present the so-far largest survey of metal absorption in Galactic high-velocity clouds (HVCs) using archival ultraviolet (UV) spectra of extragalactic background sources. The UV data are obtained with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (HST) and are supplemented by 21 cm radio observations of neutral hydrogen. Methods. Along 270 sightlines we measure metal absorption in the lines of Si ii, Si iii, Cii, and Civ and associated Hi 21 cm emission in HVCs in the velocity range jvLSRj = 100-500 km s-1. With this unprecedented large HVC sample we were able to improve the statistics on HVC covering fractions, ionization conditions, small-scale structure, CGM mass, and inflow rate. For the first time, we determine robustly the angular two point correlation function of the high-velocity absorbers, systematically analyze antipodal sightlines on the celestial sphere, and compare the HVC absorption characteristics with that of damped Lyman α absorbers (DLAs) and constrained cosmological simulations of the LG (CLUES project). Results. The overall sky-covering fraction of high-velocity absorption is 77 ± 6 percent for the most sensitive ion in our survey, Si iii, and for column densities log N(Si iii) ≥ 12.1. This value is ∼4-5 times higher than the covering fraction of 21 cm neutral hydrogen emission at log N(H i) ≥ 18.7 along the same lines of sight, demonstrating that the Milky Way's CGM is multi-phase and predominantly ionized. The measured equivalent-width ratios of Si ii, Si iii, Cii, and C iv are inhomogeneously distributed on large and small angular scales, suggesting a complex spatial distribution of multi-phase gas that surrounds the neutral 21 cm HVCs. We estimate that the total mass and accretion rate of the neutral and ionized CGM traced by HVCs is MHVC ≥ 3.0 × 109 M⊙ and dMHVC=dt ≥ 6.1 M⊙ yr-1, where the Magellanic Stream (MS) contributes with more than 90 percent to this mass/mass-flow. If seen from an external vantage point, the Milky Way disk plus CGM would appear as a DLA that would exhibit for most viewing angles an extraordinary large velocity spread of Δv ≈ 400-800 km s-1, a result of the complex kinematics of the Milky Way CGM that is dominated by the presence of the MS. We detect a velocity dipole of high-velocity absorption at low/high galactic latitudes that we associate with LG gas that streams to the LG barycenter. This scenario is supported by the gas kinematics predicted from the LG simulations. Conclusions. Our study confirms previous results, indicating that the Milky Way CGM contains sufficient gaseous material to feed the Milky Way disk over the next Gyr at a rate of a few solar masses per year, if the CGM gas can actually reach the MW disk. We demonstrate that the CGM is composed of discrete gaseous structures that exhibit a large-scale kinematics together with small-scale variations in physical conditions. The MS clearly dominates both the cross section and mass flow of high-velocity gas in the Milky Way's CGM. The possible presence of high-velocity LG gas underlines the important role of the local cosmological environment in the large-scale gas-circulation processes in and around the Milky Way.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
EDP Sciences
![Se ha confirmado la validez de este valor de autoridad por un usuario](/themes/CONICETDigital/images/authority_control/invisible.gif)
dc.rights
info:eu-repo/semantics/openAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
GALAXY: EVOLUTION
dc.subject
GALAXY: HALO
dc.subject
GALAXY: STRUCTURE
dc.subject
ISM: KINEMATICS AND DYNAMICS
dc.subject
TECHNIQUES: SPECTROSCOPIC
dc.subject
ULTRAVIOLET: ISM
dc.subject.classification
Astronomía
![Se ha confirmado la validez de este valor de autoridad por un usuario](/themes/CONICETDigital/images/authority_control/invisible.gif)
dc.subject.classification
Ciencias Físicas
![Se ha confirmado la validez de este valor de autoridad por un usuario](/themes/CONICETDigital/images/authority_control/invisible.gif)
dc.subject.classification
CIENCIAS NATURALES Y EXACTAS
![Se ha confirmado la validez de este valor de autoridad por un usuario](/themes/CONICETDigital/images/authority_control/invisible.gif)
dc.title
An HST/COS legacy survey of high-velocity ultraviolet absorption in the Milky Way's circumgalactic medium and the Local Group
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2019-12-18T13:53:07Z
dc.journal.volume
607
dc.journal.number
A48
dc.journal.pagination
1-37
dc.journal.pais
Francia
![Se ha confirmado la validez de este valor de autoridad por un usuario](/themes/CONICETDigital/images/authority_control/invisible.gif)
dc.journal.ciudad
Paris
dc.description.fil
Fil: Richter, Philipp. Universitat Potsdam. Mathematisch Nautrwissenschaften Fakultat; Alemania
dc.description.fil
Fil: Nuza, Sebastian Ernesto. Leibniz Institut Fuer Astrophysik Potsdam; Alemania. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
dc.description.fil
Fil: Fox, A. J.. Space Telescope Science Institute; Estados Unidos
dc.description.fil
Fil: Wakker, B. P.. University of Wisconsin; Estados Unidos
dc.description.fil
Fil: Lehner, N.. University of Notre Dame; Estados Unidos
dc.description.fil
Fil: Ben Bekhti, N.. Research Establishment For Applied Science (fgan);
dc.journal.title
Astronomy and Astrophysics
![Se ha confirmado la validez de este valor de autoridad por un usuario](/themes/CONICETDigital/images/authority_control/invisible.gif)
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/https://arxiv.org/pdf/1611.07024.pdf
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1051/0004-6361/201630081
Archivos asociados