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XMM-Newton observations of the merger-remnant galaxies NGC 3921 and 7252
Read, A. M.; Schweizer, François; Ponman, T. J. +1 more
Using the high sensitivity of XMM-Newton, we have studied the X-ray emission of the two prototypical late-stage merger remnants, NGC 3921 and 7252. In the case of NGC 7252, this is complemented by archival Chandra data. We investigate the nature of the discrete X-ray point source populations and the hot diffuse gas components in these two galaxies…
Pulsed flows at the high-altitude cusp poleward boundary, and associated ionospheric convection and particle signatures, during a Cluster - FAST - SuperDARN- Søndrestrøm conjunction under a southwest IMF
Balogh, A.; Rème, H.; Dunlop, M. +13 more
Available from http://www.copernicus.org/site/EGU/annales/22/8/2891.htm?FrameEngine=false;
XMM-Newton and Chandra Observations of the Central Region of M31
Kokubun, Motohide; Makishima, Kazuo; Takahashi, Hiromitsu +1 more
Archival XMM-Newton data of the central region of M31 were analyzed for diffuse X-ray emission. Point sources with 0.5-10 keV luminosity exceeding ~4×1035 ergs s-1 were detected. Their summed spectra are reproduced well by a combination of a disk blackbody component and a blackbody component, implying that the emission mainly…
On the age and mass function of the globular cluster M 4: A different interpretation of recent deep HST observations
Prada Moroni, P. G.; Paresce, F.; De Marchi, G. +1 more
Very deep images of the Galactic globular cluster M 4 (NGC 6121) through the F606W and F814W filters were taken in 2001 with the WFPC2 on board the HST. A first published analysis of this data set (Richer et al. \cite{Richer2002}) produced the result that the age of M 4 is 12.7± 0.7 Gyr (Hansen et al. \cite{Hansen2002}), thus setting a robust lowe…
Modeling the wind structure of AG Peg by fitting of C IV and N V resonance doublets
Wahlgren, G. M.; Johansson, S.; Eriksson, M.
The latest outburst of AG Peg has lasted for 150 years, which makes it the slowest nova eruption ever recorded. During the time of IUE observations (1978-1995) line profiles and intensity ratios of the N V and C IV doublet components changed remarkably, and we discuss plausible reasons. One of them is radiative pumping of Fe II which is investigat…
Hubble Space Telescope Spectroscopy of Four Luminous Compact Blue Galaxies at Intermediate Redshift
Hoyos, C.; Koo, D. C.; Guzmán, R. +2 more
We present a spectroscopic study of four blue (B-V<=0.6) compact (µB<=21.0 mag arcsec-2) field galaxies with redshifts 0.095<=z<=0.438 and absolute magnitudes MB between -17.5 and -21.1. The spectra, taken with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, show prom…
Number counts of bright extremely red objects: Evolved massive galaxies at z ∼1
Väisänen, P.; Johansson, P. H.
We present results on number counts of Extremely Red Objects (EROs) in a 2850 arcmin2 near-infrared survey performed in European Large Area ISO Survey (ELAIS) fields at K<17.5. Counts of EROs are extended to brighter levels than available previously, giving 0.002 ± 0.001 arcmin-2 at K<16.5 and consistent numbers with li…
Discrete modes and turbulence in a wave-driven strongly magnetized plasma
Matthaeus, William H.; Lanzerotti, Louis J.; Dmitruk, Pablo
We show the coexistence of discrete modes and turbulence in numerical experiments of magnetohydrodynamics with a strong background magnetic field. The particular system we consider is a model of an open magnetic region which we have previously used in coronal heating studies. In the simulations shown here, Alfven waves at discrete frequencies with…
ISO far infrared observations of the high latitude cloud L 1642. I. The density and temperature structure
Juvela, M.; Lemke, D.; Russeil, D. +2 more
We have performed a large-scale mapping of the high-latitude, moderate extinction dark cloud L 1642 with ISO (Infrared Space Observatory) at 200 µm to study the properties of dust, the virial equilibrium condition of the cloud, and their relation to star formation. The cloud consists of three denser regions which are connected by diffuse mat…
Concerning the White Dwarf Cooling Age of M4: A Reply to De Marchi et al. on ``A Different Interpretation of Recent Deep HST Observations''
Stetson, P. B.; Rich, R. M.; Shara, M. +7 more
We respond to the recent paper by De Marchi et al. on the white dwarf cooling age of M4. The authors question the data analysis and interpretation that led to our conclusions in Hansen et al. in 2002. In their paper, De Marchi et al. are unable to obtain photometry as deep as ours from the same data set and therefore assert that only a lower limit…