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Stellar populations in the Local Group starburst galaxy IC10

Giuffrida, G.; Pulone, L.; Sanna, N. +10 more

We present preliminary results of a photometric investigation on IC10 using F555W and F814W data collected with WFPC2@HST covering two different regions. We provide a new estimate of both distance and reddening by adopting the Tip of the Red Giant Branch (TRGB). We find that the RGB stars in the two regions are located at the same distance, but pr…

The FR II Broad-Line Seyfert 1 Galaxy: PKS J1037-2705

Clarke, Tracy E.; Punsly, Brian; Tingay, Steven +3 more

In this article we demonstrate that PKS J1037-2705 has a weak accretion flow luminosity, well below the Seyfert 1/QSO dividing line, weak broad emission lines (BELs), and moderately powerful FR II extended radio emission. It is one of the few documented examples of a broad-line object in which the time-averaged jet kinetic luminosity, \overline{Q}…

From Maxwell's theory of Saturn's rings to the negative mass instability

Fedele, Renato

Cross-identifications of stars with high proper motions (Version 2.0)

Ivanov, G. A.

A cross index list of 493 200 stars with proper motions higher than 0.04″/yr (ftp://ftp.mao.kiev.ua/pub/astro/c-ihpms2) was compiled on the basis of the original determinations for the FONAK1.1 catalog stars, the data from the Hipparcos, Tycho-2, UCAC2, CMC (STAR 11), PPM, NPM1, NPM2, XZ80Q, Pul-3, PUL2, GCVS, NLTT, LHS, Lowell Proper Motion, and …

Constraints on the Velocity and Spatial Distribution of Helium-like Ions in the Wind of SMC X-1 from Observations with the XMM-Newton Reflection Grating Spectrometer

Kallman, Timothy R.; Liedahl, Duane A.; Wojdowski, Patrick S.

We present here X-ray spectra of the HMXB SMC X-1 obtained in an observation with the XMM-Newton observatory beginning before eclipse and ending near the end of eclipse. With RGS on board XMM-Newton, we observe emission lines from hydrogen-like and helium-like ions of nitrogen, oxygen, neon, magnesium, and silicon. Although the resolution of the R…

Determination of the IMF in the LMC Stellar Cluster NGC 2156

Silva-Villa, E.; Sirianni, M.; Zuluaga, J.

We present a study on the IMF of the stellar cluster NGC 2156 in the LMC from deep HST-WFPC2 images in the bands F555W and F814W. The study is part of a larger program to investigate whether the IMF at low stellar masses is dependent on local conditions by observing young globular clusters in the LMC and the SMC. We detected stars down to a limiti…

BVRI photometric analysis for the galaxy group NGC 4410

Meaburn, J.; Katsiyannis, A. C.; Khosroshahi, H. G. +4 more

We present a BVRI CCD (Charge Coupled Device) surface photometry analysis of the galaxy group NGC 4410, which contains four galaxies in interaction. Along with our photometric study, we show residual images (after subtracting isophotal models) and unsharp masked images to uncover any hidden structures in this system of galaxies; we have also perfo…

3D MHD reconnection model coupled with Cluster multi-spacecraft data

Nilsson, Hans; Balogh, André; Westerberg, Lars G. +2 more

We present a model where a three-dimensional viscous/resistive analytical model of the large scale plasma flow in the outflow region about a reconnection site at the dayside magnetopause, is coupled with multispacecraft measurements from the Cluster satellite armada. A total of ten magnetopause crossings have been analyzed during the period 10:29-…

X-ray spectroscopy of early-type stars: The present and the future

Nazé, Y.; Rauw, G.; Oskinova, L. M.

XMM-Newton and Chandra have boosted our knowledge about the X-ray emission of early-type stars (spectral types OB and Wolf-Rayet). However, there are still a number of open questions that need to be addressed in order to fully understand the X-ray spectra of these objects. Many of these issues require high-resolution spectroscopy or monitoring of …

Using X-ray observations to identify the particle acceleration mechanisms in VHE SNRs and ``dark'' VHE sources

Pühlhofer, G.

Very high energy (VHE) γ-ray observations have proven to be very successful in localizing Galactic acceleration sites of VHE particles. Observations of shell-type supernova remnants have confirmed that particles are accelerated to VHE energies in supernova blast waves; the interpretation of the γ-ray data in terms of hadronic or leptonic particle …