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In this paper we present for the first time high spatial resolution K-band maps of the central kinematical and near-infrared spectral properties of the giant cD galaxy in the Fornax cluster, NGC 1399. We confirm the presence of a central velocity dispersion dip within radius < 0.2" seen in previous long-slit studies. Our velocity dispersion maps give evidence for a non-symmetric structure in this central area by showing three sigma peaks to the north-east, south-east and west of the galaxy centre. Additionally we measure near-IR line strength indices at unprecedented spatial resolution in NGC 1399. The most important features we observe in our 2-dimensional line strength maps are drops in Na I and CO(2-0) line strength in the nuclear region of the galaxy, coinciding spatially with the drop in sigma. The observed line strength and velocity dispersion changes suggest a scenario where the centre of NGC 1399 harbours a dynamically cold subsystem with a distinct stellar population., Comment: 9 pages, 5 figures, accepted for publication in A&A

New measurements of K-band spectral features are presented for eleven early-type galaxies in the nearby Fornax galaxy cluster. Based on these measurements, the following conclusions have been reached: (1) in galaxies with no signatures of a young stellar component, the K-band Na I index is highly correlated with both the optical metallicity indicator [MgFe]' and central velocity dispersion; (2) in the same galaxies, the K-band Fe features saturate in galaxies with sigma > 150 km/s while Na I (and [MgFe]') continues to increase; (3) [Si/Fe] (and possibly [Na/Fe]) is larger in all observed Fornax galaxies than in Galactic open clusters with near-solar metallicity; (4) in various near-IR diagnostic diagrams, galaxies with signatures of a young stellar component (strong Hbeta, weak [MgFe]') are clearly separated from galaxies with purely old stellar populations; furthermore, this separation is consistent with the presence of an increased number of M-giant stars (most likely to be thermally pulsating AGB stars); (5) the near-IR diagrams discussed here seem as efficient for detecting putatively young stellar components in early-type galaxies as the more commonly used age/metallicity diagnostic plots using optical indices (e.g Hbeta vs. [MgFe]')., Comment: 47 pages, 16 figures, ApJ accepted

A sample of carbon-rich stars (C-stars) in the Small Magellanic Cloud (SMC) was selected from the combined 2MASS and DENIS catalogues on the basis of their $J-K_s$ colour. This sample was extended to include confirmed C--stars from the Rebeirot et al. (1993) spectroscopic atlas. In this combined sample (N = 1152), a smaller number (N = 1079) were found to have MACHO observations. For this sub--sample, light curves were determined and 919 stars were found to have high quality light-curves with amplitudes of at least 0.05 mag. Of these stars, only 4% have a well--defined single period -- most of these have multiple well-defined periods, while 15% have highly irregular light--curves. The distribution of the logarithm of the period versus magnitude, colour, period ratio (if applicable), and amplitude was analyzed and compared with previous works. Variable C-stars are distributed in three sequences: B, C and D from Wood et al. (1999), and do not populate sequences with periods shorter than $\log P \sim 1.5$. Stellar ages and masses were estimated using stellar evolutionary models., Comment: 18 pages, 22 figures, 3 tables, A&A Accepted (2005 March 18), added a reference, corrected typos

Long Period Variable stars are ubiquitous among the bright red giant branch stars in NGC 5128. Mostly they are found to be brighter than the tip of the first ascent giant branch with magnitudes ranging from about K=19 to K=21.5. They have periods between 155 and 1000 days and K-band amplitudes between 0.1 and 2 mag, characteristic of semi-regular and Mira variables. We compare the colors, periods and amplitudes of these variables with those found in old stellar populations like Galactic globular clusters and Galactic bulge as well as with intermediate-age Magellanic Cloud long period variables. The population of stars above the tip of the red giant branch (RGB) amounts to 2176 stars in the outer halo field (Field 1) and 6072 stars in the inner halo field (Field 2). The comparison of the luminosity functions of the Galactic bulge, M31 bulge and NGC 5128 halo fields shows an excess of bright AGB stars extending to M_K ~ -8.65. The large majority of these sources belong to the asymptotic giant branch (AGB) population in NGC 5128. Subtracting the foreground Galactic stars and probable blends, at least 26% and 70% of AGB stars are variable in Fields 1 and 2, respectively. The average period of NGC 5128 LPVs is 395 days and the average amplitude 0.77 mag. Many more short period Miras are present in Field 2 than in Field 1 indicating a difference in the stellar populations between the two fields. Period and amplitude distributions and near-IR colors of the majority of LPVs in NGC 5128 are similar to the Galactic bulge variables. However, some ~10% of LPVs have periods longer than 500 days and thus probably more massive, hence younger, progenitor stars. A few carbon star candidates are identified based on their red J-H and H-K colors., Comment: 11 pages, 10 figures; accepted for publication in A&A; for high resolution version see: http://www.eso.org/~mrejkuba/cenA_LPVs_IRprop.ps The catalogue (Paper I) can be downloaded from http://www.eso.org/~mrejkuba/cenA_LPVs_cat.ps

The first variable star catalogue in a giant elliptical galaxy NGC 5128 (Centaurus A) is presented. Using multi-epoch observations with ISAAC at the VLT we have detected 1504 red variables in two halo fields covering 10.46 arcmin square. For the variables with at least 10 good measurements, periods and amplitudes were determined using Fourier analysis and non-linear sine-curve fitting algorithms. The final catalogue contains 1146 long period variables with well established light curve parameters. Periods, amplitudes, JsHKs photometry as well as individual Ks-band magnitudes are provided for all the variables. The distribution of amplitudes ranges from 0.3 to a few magnitudes in the Ks-band, with a median value around 0.7 mag. The amplitudes, mean magnitudes and periods indicate that the majority of variables belong to the class of long period variables with semiregular and Mira variables. Exhaustive simulations were performed in order to assess the completeness of our catalogue and the accuracy of the derived periods., Comment: 14 pages, 14 figures; Some figures are highly compressed. For a full resolution version see http://www.eso.org/~mrejkuba/cenA_LPVs_cat.ps This is a complete version of the article to appear in the electronic version of A&A. A&A accepted

We have measured the Hubble constant Ho in NGC 564 at cz ~ 5800 km/s and in NGC 7619 at cz ~ 3700 km/s with deep I-band Surface Brightness Fluctuation distance measurements at the ESO Very Large Telescope (VLT). We obtain Ho = 70 +/- 7 +/- 6 km/s/Mpc for NGC 564 and Ho = 68 +/- 6 +/- 6 km/s/Mpc for NGC 7619. The actual SBF sample used for the measurement of Ho in the Hubble Space Telescope Key Project on the Extragalactic Distance Scale (Freedman et al. 2001) amounts to six galaxies. When we combine the measurements from this work with our previous VLT I-band SBF distance measurement in IC 4296 (Mei et al. 2000), we obtain : Ho = 68 +/- 5 +/- 6 km/s/Mpc. When we add the Freedman et al. (2001) SBF sample, we obtain Ho = 71 +/- 4 +/- 6 km/s/Mpc., Comment: 9 pages, 4 figures. Accepted for publication in A&A

We used the direct CCD camera at the Magellan I telescope at Las Campanas Observatory and FORS1 at Antu VLT at ESO Paranal Observatory to image fields centered on the inner and outer optical filaments in the halo of NGC 5128. In the V vs. U-V color-magnitude diagrams we have identified young blue supergiants associated with these line-emitting filaments located between the inner radio lobe and the northern middle lobe. Around the outer filament stars as young as 10 Myr were detected. They are principally aligned with the direction of the radio jet, but a vertical north-east alignment along the edge of the HI cloud is also present. Young stars in the inner filament field are found inside the bright knots of photoionized gas and are strongly aligned in the direction towards the center of the galaxy at the same position angle as the inner radio jet. Fitting the Padova isochrones on UV color-magnitude diagrams we find that the blue stars around the inner filaments have ages similar to the ones around the outer filaments ~10-15 Myr and the same abundance of Z=0.004. The presence of young blue supergiants clearly shows that the bright blue knots in the north-eastern halo of NGC 5128 are associations of young stars with photoionized gas. The temperature of the brightest stars is T \~ 12000-16000 K, insufficient to account alone for the high excitation lines observed in the surrounding ionized gas. Thus the optical emission jet is principally seen due to its alignment with the radio structure of the AGN. The highly collimated star formation is present only in the north eastern halo of the galaxy, suggesting the interaction of the jet with the gas clouds deposited during the last accretion event as the preferred triggering mechanism. (abridged), Comment: 10 pages, 5 figures; to be published in ApJ, v565 n1, January 20, 2002 issue

We resolve stars of the nearest giant elliptical galaxy NGC 5128 using VLT with FORS1 and ISAAC. We construct deep U, V and Ks color-magnitude and color-color diagrams in two different halo fields (in the halo and in the north-eastern diffuse shell). In the outer, shell field, at ~14 kpc from the center of the galaxy, there is a significant recent star formation with stars as young as 10 Myr, approximately aligned with the prominent radio and x-ray jet from the nucleus of the host AGN. Ionized gas filaments are evident in ultraviolet images near the area where neutral HI and CO molecular gas was previously observed. The underlying stellar population of the halo of the giant elliptical is predominantly old with a very broad metallicity distribution. The presence of an extended giant branch reaching M_bol=-5 mag suggests the existence of a significant intermediate-age AGB population in the halo of this galaxy., Comment: 18 pages, 18 figures; to be published in A&A; high res. version at http://www.eso.org/~mrejkuba/cenA_starsVLT.ps

From theoretical predictions, the introduction of 8-m class telescopes permits one to extend Surface Brightness Fluctuations measurements from the ground to ~7000 km/s, with a precision that is comparable to current space-based measurements. We have measured I--band SBF in IC 4296 in Abell 3565 cz~3630 km/s with the ESO Very Large Telescope. Adopting the Tonry et al. (2000) calibration for I-band SBF we determined a distance modulus of (I_o,k - M_I)=33.44 +/- 0.17 mag corresponding to a galaxy distance of 49 +/- 4 Mpc. This result is consistent with the HST observation from Lauer et al. (1998): (I_F814 - M_F814) = 33.47 +/- 0.13 mag.

Anomalously high K-band surface brightness fluctuations (SBF) have been reported in NGC 4489 by Pahre & Mould (1994), Jensen et al. (1996) and Jensen et al. (1998). However, these conclusions were uncertain because of relatively low signal-to-noise data. New high signal-to-noise data for NGC 4489 have been obtained at the NOAO/KPNO 2.1m and the ESO/La Silla 3.5m NTT telescopes. Adopting the I-band SBF distance modulus determined by Tonry et al. (1990) and the M_I versus (V-I) calibration of Tonry et al. (2000), a value of M_K =-6.18 +/-0.09 mag was derived. Relative to the average empirical M_K derived for giant ellipticals by Jensen et al. (1998) (M_K=-5.61 +/- 0.12 mag), the detection of an anomalous K-band SBF in NGC 4489 is confirmed at the two sigma level. Such anomalous fluctuations could be caused by an extended giant branch, consisting of either intermediate-age AGB stars above the tip of the first-ascent giant branch or high-metallicity first-ascent giants, or by lack of a full understanding of the K-band SBF calibration. This result raises questions about the accuracy of K-band SBF distance measurements for elliptical galaxies with unknown stellar composition and underscores the need for M_K measurements over a larger range of color and luminosity., Comment: A&A, in press