scholarly journals Hot Gaseous Halo in the Elliptical and Spiral Galaxies

1998 ◽  
Vol 188 ◽  
pp. 57-60
Author(s):  
H. Awaki
Keyword(s):  
Stellar Population ◽  
Spiral Galaxies ◽  
Massive Stars ◽  
Stellar Populations ◽  
Elliptical Galaxies ◽  
Starburst Galaxies ◽  
Physical Parameters ◽  
X Ray ◽  
Hot Gas ◽  
Gaseous Halo

The Einstein observations revealed that starburst and luminous elliptical galaxies had X-ray halo. These galaxies have quite different stellar population. Starburst galaxies contain young massive stars, while elliptical galaxies generally contain an old-metal rich population dominated by K and M giants. Therefore a question is why these two type of galaxies commonly have hot gas, in spite of quite different stellar populations. In order to address this question, we observed these galaxies with ASCA. In this paper, I would like to present observational results, then compare the physical parameters of the hot gas in these galaxies.

scholarly journals Rejuvenation of spiral bulges

2007 ◽  
Vol 3 (S245) ◽  
pp. 289-292
Author(s):  
Daniel Thomas ◽  
Roger L. Davies
Keyword(s):  
Stellar Population ◽  
Velocity Dispersion ◽  
Spiral Galaxies ◽  
Stellar Populations ◽  
Elliptical Galaxies ◽  
Element Abundances ◽  
Secular Evolution ◽  
The Past ◽  
Show Evidence ◽  
Inside Out

AbstractWe seek to understand whether the stellar populations of galactic bulges show evidence of secular evolution triggered by the presence of the disc. To this end we re-analyse the sample of Proctor & Sansom (2002), deriving stellar population ages and element abundances from absorption line indices as functions of central velocity dispersion and Hubble type. In agreement with other studies in the literature, we find that bulges have relatively low luminosity weighted ages, the lowest age derived being 1.3 Gyr. Hence bulges are not generally old, but actually rejuvenated systems. We discuss evidence that this might be true also for the bulge of the Milky Way. The smallest bulges are the youngest with the lowest α/Fe ratios indicating the presence of significant star formation events involving 10 − 30 per cent of their total mass in the past 1 − 2 Gyr. No significant correlations of the stellar population parameters with Hubble Type are found. We show that the above relationships with σ coincide perfectly with those of early-type galaxies. At a given velocity dispersion, bulges and elliptical galaxies are indistinguishable as far as their stellar populations are concerned. These results favour an inside-out formation scenario and indicate that the discs in spiral galaxies of Hubble types Sbc and earlier cannot have a significant influence on the evolution of the stellar populations in the bulge component. The phenomenon of pseudobulge formation must be restricted to spirals of types later than Sbc.

scholarly journals Chandra X-ray Observations of Dwarf Starburst Galaxies

2004 ◽  
Vol 217 ◽  
pp. 304-309
Author(s):  
Jürgen Ott ◽  
Fabian Walter ◽  
Elias Brinks ◽  
Ulrich Klein
Keyword(s):  
Interstellar Medium ◽  
Gravitational Potential ◽  
Thermal Plasma ◽  
Theoretical Models ◽  
Starburst Galaxies ◽  
Host Galaxy ◽  
X Ray ◽  
Hot Gas ◽  
Neutral Gas

We obtained X-ray observations for a sample of eight nearby dwarf starburst galaxies from the Chandra X-ray Observatory. Five galaxies of our sample show extended (size: 1-10 kpc), diffuse X-ray emission which can be attributed to a hot thermal plasma. This phase of the interstellar medium purportedly drives the expansion of supergiant shells. A comparison of the derived gas parameters with theoretical models reveals that the hot gas in principle is capable to escape from the gravitational potential of the host galaxy. However, the outflows appear to be contained in those cases where an extended envelope or massive tidal features of neutral gas exist.

scholarly journals Simulated X-Ray Emission from Starburst Driven Winds

1998 ◽  
Vol 188 ◽  
pp. 287-288
Author(s):  
D. K. Strickland ◽  
I. R. Stevens ◽  
T. J. Ponman
Keyword(s):  
Galaxy Evolution ◽  
Massive Stars ◽  
Temperature Structure ◽  
Mass Loading ◽  
X Ray ◽  
Chemical Enrichment ◽  
Hot Gas ◽  
Galactic Winds ◽  
Complex Temperature ◽  
Initial Results

Winds from massive stars and supernovae in starburst galaxies drive global outflows of hot X-ray emitting plasma, as seen in M82 and NGC 253. These galactic winds are important for understanding galaxy evolution & formation, chemical enrichment of the IGM, and the starburst phenomenon itself.X-ray observations provide the only direct probe of the hot gas in these winds. However, the limitations of current X-ray observatories and factors such as complex temperature structure, mass loading by ambient material and projection effects all make the link between the observed data and existing 1 & 2-D modeling and theory difficult to make.We have therefore begun a program of numerical simulations of galactic winds, concentrating on predicting their observable X-ray properties. We present some initial results, comparing them to the archetypal starburst wind system M82.

scholarly journals 30 Doradus as a Nearby Infrared Guide to Starbursts

1999 ◽  
Vol 190 ◽  
pp. 247-248 ◽  
Author(s):  
M. D. Thornley ◽  
N.M. Förster Schreiber ◽  
H.W.W. Spoon ◽  
R. Genzel ◽  
D. Lutz ◽  
...  
Keyword(s):  
Fine Structure ◽  
Short Wavelength ◽  
Massive Stars ◽  
Stellar Populations ◽  
Starburst Galaxies ◽  
Fine Structure Lines ◽  
30 Doradus

We are exploring the properties of obscured starburst galaxies, using observations of atomic fine structure lines taken with the Short Wavelength Spectrometer aboard ISO. However, it is important to ascertain how well our starburst models can recover the properties of the stellar populations in more distant starbursts. For this purpose, we use observations of a nebular “shell” in the 30 Doradus region, to show that our models reliably predict the presence of the very massive stars observed directly in the 30 Doradus region.

scholarly journals The X-ray stellar population of the LMC

2008 ◽  
Vol 4 (S256) ◽  
pp. 20-29 ◽  
Author(s):  
Yaël Nazé
Keyword(s):  
Stellar Population ◽  
Main Sequence ◽  
Massive Stars ◽  
High Energy ◽  
Magellanic Clouds ◽  
X Rays ◽  
X Ray ◽  
Energy Domain ◽  
X Ray Binaries

AbstractIn the study of stars, the high energy domain occupies a place of choice, since it is the only one able to directly probe the most violent phenomena: indeed, young pre-main sequence objects, hot massive stars, or X-ray binaries are best revealed in X-rays. However, previously available X-ray observatories often provided only crude information on individual objects in the Magellanic Clouds. The advent of the highly efficient X-ray facilities XMM-Newton and Chandra has now dramatically increased the sensitivity and the spatial resolution available to X-ray astronomers, thus enabling a fairly easy determination of the properties of individual sources in the LMC.

scholarly journals The Galaxy Merger Origin of Hot Gaseous Halos of Ellipticals

2004 ◽  
Vol 217 ◽  
pp. 412-417
Author(s):  
X. Y. Xia ◽  
Z. Y. Huo ◽  
S. J. Xue
Keyword(s):  
Central Region ◽  
Elliptical Galaxies ◽  
Emission Lines ◽  
Central Nucleus ◽  
Nuclear Region ◽  
Feedback Process ◽  
X Ray ◽  
The Galaxy ◽  
Low Metallicity ◽  
Gaseous Halo

We report on the properties of the hot gaseous halos of 10 nearby ultraluminous IRAS galaxies from Chandra observations. There exists diffuse soft X-ray emission surrounding the central nucleus within 10 kpc of the nuclear region with a temperature of about 0.7 keV and metallicity about Z ~ 1.0Z⊙. Also, emission lines from α elements and ions for are seen in all nearby ULIRGs in our sample. Outside the central region, the Chandra observations reveal a more extended hot gaseous halo with a temperature of about 0.6 keV and low metallicity (Z ~ 0.1Z⊙) for some of the ULIRGs. We discuss the nature and the implications of our results for the origin of X-ray halos in elliptical galaxies and the constraints this places on the feedback process.

scholarly journals Spectroscopic study of formation, evolution and interaction of M31 and M33 with star clusters

2014 ◽  
Vol 10 (S312) ◽  
pp. 201-202 ◽  
Author(s):  
Zhou Fan ◽  
Yanbin Yang
Keyword(s):  
Globular Clusters ◽  
Stellar Population ◽  
Local Group ◽  
Spiral Galaxies ◽  
Star Clusters ◽  
Star Cluster ◽  
Physical Parameters ◽  
Cluster Systems ◽  
Nearby Galaxies ◽  
Formation And Evolution

AbstractThe recent studies show that the formation and evolution process of the nearby galaxies are still unclear. By using the Canada France Hawaii Telescope (CFHT) 3.6m telescope, the PanDAS shows complicated substructures (dwarf satellite galaxies, halo globular clusters, extended clusters, star streams, etc.) in the halo of M31 to ~150 kpc from the center of galaxy and M31-M33 interaction has been studied. In our work, we would like to investigate formation, evolution and interaction of M31 and M33, which are the nearest two spiral galaxies in Local Group. The star cluster systems of the two galaxies are good tracers to study the dynamics of the substructures and the interaction. Since 2010, the Xinglong 2.16m, Lijiang 2.4m and MMT 6.5m telescopes have been used for our spectroscopic observations. The radial velocities and Lick absorption-line indices can thus be measured with the spectroscopy and then ages, metallicities and masses of the star clusters can be fitted with the simple stellar population models. These parameters could be used as the input physical parameters for numerical simulations of M31-M33 interaction.

scholarly journals Abundance ratios in stars vs. hot gas in elliptical galaxies

2009 ◽  
Vol 5 (H15) ◽  
pp. 281-281
Author(s):  
Antonio Pipino
Keyword(s):  
Interstellar Medium ◽  
Chemical Evolution ◽  
Elliptical Galaxies ◽  
Evolution Model ◽  
X Ray ◽  
Galactic Wind ◽  
Hot Gas ◽  
Self Consistent ◽  
Chemical Evolution Model ◽  
Gas Properties

AbstractI present predictions from a chemical evolution model for a self-consistent study of optical (i.e., stellar) and X-ray (i.e., gas) properties of present-day elliptical galaxies. Detailed cooling and heating processes in the interstellar medium are taken into account and allow a reliable modelling of the SN-driven galactic wind. The model simultaneously reproduces the mass-metallicity, colour-magnitude, LX - LB and LX - T relations, and the observed trend of [Mg/Fe] with σ. The "iron discrepancy" can be solved by taking into account the dust presence.

scholarly journals Deep XMM-Newton observations of the northern disc of M31

2020 ◽  
Vol 637 ◽  
pp. A12
Author(s):  
Patrick J. Kavanagh ◽  
Manami Sasaki ◽  
Dieter Breitschwerdt ◽  
Miguel A. de Avillez ◽  
Miroslav D. Filipović ◽  
...  
Keyword(s):  
Massive Stars ◽  
Low Density ◽  
Plasma Properties ◽  
X Ray ◽  
Star Forming ◽  
Hot Gas ◽  
Grand Design ◽  
Multi Wavelength ◽  
Multi Phase ◽  
Extended Emission

Aims. We use new deep XMM-Newton observations of the northern disc of M31 to trace the hot interstellar medium (ISM) in unprecedented detail and to characterise the physical properties of the X-ray emitting plasmas. Methods. We used all XMM-Newton data up to and including our new observations to produce the most detailed image yet of the hot ISM plasma in a grand design spiral galaxy such as our own. We compared the X-ray morphology to multi-wavelength studies in the literature to set it in the context of the multi-phase ISM. We performed spectral analyses on the extended emission using our new observations as they offer sufficient depth and count statistics to constrain the plasma properties. Data from the Panchromatic Hubble Andromeda Treasury were used to estimate the energy injected by massive stars and their supernovae. We compared these results to the hot gas properties. Results. The brightest emission regions were found to be correlated with populations of massive stars, notably in the 10 kpc star-forming ring. The plasma temperatures in the ring regions are ~0.2 up to ~0.6 keV. We suggest this emission is hot ISM heated in massive stellar clusters and superbubbles. We derived X-ray luminosities, densities, and pressures for the gas in each region. We also found large extended emission filling low density gaps in the dust morphology of the northern disc, notably between the 5 and 10 kpc star-forming rings. We propose that the hot gas was heated and expelled into the gaps by the populations of massive stars in the rings. Conclusions. It is clear that the massive stellar populations are responsible for heating the ISM to X-ray emitting temperatures, filling their surroundings, and possibly driving the hot gas into the low density regions. Overall, the morphology and spectra of the hot gas in the northern disc of M31 is similar to other galaxy discs.

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