We report on some of the recent work that has come from our Hubble Space Telescope programme to find massive black holes in nearby spiral galaxies. Determining black hole masses from gas kinematics in spiral galaxies is difficult, but results have been reported for NGC 4041 and new results are soon to be reported for NGC 1300 and NGC 2748. Complementary programmes are also looking for the presence of nuclear star clusters in our Space Telescope Imaging Spectrograph (STIS) and archival Near-infrared Camera and Multi-Object Spectrometer (NICMOS) images. We are also currently analysing United Kingdom Infrared Telescope (UKIRT) Fast Track Imager (UFTI) near-infrared images to determine the surface brightness profiles for 37 of the galaxies in the sample.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the results of a spectrophotometric study of star forming regions in HII galaxies. In particular, we find that, besides their “blobbiness”, HII galaxies are quite homogenous in their chemical properties, though we do see important fluctuations in some physical properties (e.g. extinction).To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We used the near-infrared [Fe II] emission line signature of shock-heating to detect supernova remnants (SNRs) in nearby starburst galaxies. The near-IR narrow-band imaging program has led to the detection of SNR candidates in NGC 1569 and NGC 5253, both host to super-star clusters. A spatially extended component to the [Fe II] line emission dominates the integrated [Fe II] luminosity in the two galaxies. Despite the starburst environment, the [Fe II] luminosity of the individual SNRs is two orders of magnitude lower than the luminosities observed for SNRs in M82. We find that the density and the structure of the interstellar medium is a more important factor than the starburst nature of a galaxy in determining the average [Fe II] luminosity of a SNR. The observations suggest that a significant fraction of the ISM in NGC 1569 and NGC 5253 is under the influence of SNRs. This does not appear to be the case in M82 where the impact of the SNRs is limited to high density knots.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present the results of a new stellar population synthesis code which mixes both evolutionary and empirical population synthesis techniques. The code decomposes a given galaxy spectrum into a base of high resolution spectra from the recent evolutionary synthesis models of Bruzual & Charlot (2003). The main novelty is that now we synthesize the whole Fλ spectrum, rather than a handful of absorption lines and colors.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We study the global effects of the clouds-SN shock wave interactions on the mixing of the gas in Starburst galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present a semi-analytic model able to trace the thermalisation history of the ISM in a Starburst region and determine the SN heating efficiency evolution.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We analyze long slit spectroscopy of NGC 1052, the third brightest member of a group of eleven galaxies. This elliptical is a typical LINER with a stellar rotating disk. We have found a strong negative radial gradient of the abundance ratio Mg/Fe, which suggests an enhancement of α-elements particulary towards the nuclear region, and higher metallicity and age at the galactic nucleus too. We have measured the Lick line-strength indices along the major axis of the galaxy. This information, together with single-aged stellar population models of Thomas et al. (2003), was used to determine the star formation history of NGC 1052.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We carried out a spectroscopic survey of a sample of 59 Seyfert nuclei (observed both in the northern and in the southern hemisphere) around the stellar absorption lines of Calcium II at 8498.02, 8542.09 and 8662.14 Å (CaT). Our main goal is to determine their stellar velocity dispersions. These measurements, along with photometric information, will allow us to obtain the M/L ratio, useful to determine the nature of the ∼33% of “ambiguous” Seyfert 2.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We investigate the relation between the asymptotic circular velocity, $V_{\rm circ}$, and the central stellar velocity dispersion, $\sigma_{\rm c}$, in galaxies. We consider a new sample of high surface brightness spiral galaxies (HSB), low surface brightness spiral galaxies (LSB), and elliptical galaxies with HI-based $V_{\rm circ}$ measurements. We find that: 1) elliptical galaxies with HI measurements fit well within the relation; 2) a linear law can reproduce the data as well as a power law (used in previous works) even for galaxies with $\sigma_{\rm c} \lt 70$ km/s; 3) LSB galaxies, considered for the first time with this respect, seem to behave differently, showing either larger $V_{\rm circ}$ values or smaller $\sigma_{\rm c}$ values.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We characterize the stellar population of a complete sample of the closest southern radio-galaxies – 12 Fanaroff-Riley I (FR I), 8 FR II and 4 with undefined FRx type – and a comparison sample of 18 non-active elliptical and SO galaxies. We measured equivalent widths and continuum colours and their radial variations, and performed spectral synthesis as a function of distance from the nucleus. Only 4 of the radio-galaxies have more than 10% of the total flux at 4020Å contributed from 100 Myr old or younger stellar population components – including a featureless continuum due to an AGN. All 4 are FRII or FRx. The main difference between the stellar population of the radio-galaxies and that of the non-active ones is that the former have a larger contribution of the intermediate age component, suggesting a relation between the present radio activity and a past episode of star formation which occurred about 1 Gyr ago.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

In this work we investigate the stellar population, metallicity distribution and ionized gas in the elliptical galaxy NGC 5044, using long-slit spectroscopy and a stellar population synthesis method. We found differences in the slope of FeI and Mg2 lines gradients, which suggests an enhancement of α elements, particularly towards the central region. The stellar population synthesis shows that the contribution, at λ5870, of the most metallic and old stellar population ($Z/Z_\odot \sim 0.0$ and 1010year) is dominant in NGC 5044. The presence of a non-thermal ionization source, such as a low-luminosity AGN and/or shock ionization, is implied by the large values of the ratio [NII]/Hα observed in all sampled regions. However, the emission lines observed in the external regions indicate the presence of an additional ionization source, probably hot, post-AGB stars.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The kinematics of black hole and neutron star X-ray binaries in the Galaxy should help to know their birth place and constrain their evolution. We have used multiple tools of modern astronomy to determine the trajectories in the Galaxy and track the origins of black hole and neutron star X-ray binaries that are of topical interest in astrophysics. We find three distinct classes of black hole and neutron star X-ray binaries: (1) low mass X-ray binaries that move at high velocities on galactocentric orbits similar to the most ancient stars born in the Galactic bulge and the halo, (2) those that move in the Galactic disk along paths that resemble the circular orbits of massive stars formed in the disk, and (3) high and intermediate mass X-ray binaries running away from their parent regions of star formation. Here we discuss some of the cases studied.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

High resolution B, V, I imaging of the inner region of the spiral barred galaxy NGC 7479 suggests this galaxy contains a pseudo nuclear ring and possibly a nuclear bar.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present and discuss results concerning a study of stellar populations in the galaxies belonging to CL 0048-2942, a cluster at intermediate redshift (z = 0.64), and to the field. This study gives insight on the evolutionary stage of the cluster galaxies at different radial distances from the cluster centre. We find a population gradient within the cluster: centre galaxies host older stars whereas galaxies located towards the cluster outskirts are predominantly made of less evolved stars. This effect is even more pronounced as we move outside the cluster, into the field. This is interpreted as star formation being more intense in the field, or rather, suppressed within the cluster, particulary as we move towards its centre.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

By means of 2D spectroscopy we have found a lot of compact inner stellar and gaseous disks in morphologically normal galaxies. The evolution and spatial orientation of these inner structures are often decoupled from the evolution and spatial orientation of the large-scale galactic disks and bulges. We argue that this finding requires substantial change of common approaches to investigations of the central parts of galaxies, including central black hole studies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The properties of stellar populations in the centers of nearby lenticular galaxies are investigated by means of 2D spectroscopy. All the galaxies are divided into 4 groups depending on the environment type; every subsample contains more than 10 galaxies. Clear distinctions between the mean stellar ages and abundance ratios are found both for the nuclei and for the bulges of the S0s in the different environments.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Here we present a self-consistent stationary solution for spherically symmetric winds driven by massive star clusters under the impact of radiative cooling. We demonstrate that cooling may modify drastically the distribution of temperature and the observational appearance of star cluster winds if the rate of injected energy approaches a critical value, and that the stationary wind solution does not exist if the energy deposition rate exceeds this limit.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Using spectra of normal emission line galaxies from the First Data Release of the Sloan Digital Sky Survey (SDSS) we have investigated the relations between the extinction C(Hβ) as derived from the Hα/Hβ emission line ratio and various global parameters of the galaxies. Our main findings include: C(Hβ) is linked with the galaxy spectral type and colour, decreasing from early- to late-type spirals. It also increases with increasing metallicity and is larger for more luminous galaxies and those with older stellar populations. The extinction of the stellar light is correlated with both the extinction of the nebular light and the intrinsic galaxy colours. The optical properties of the luminous infrared galaxies in our SDSS sample are very similar to those of our entire sample of SDSS galaxies. These results have implications for the determination of global star formation rates and total stellar masses in normal galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We analyse the stellar content of a large number of HII galaxies based on the continuum and absorption features of their spectra using population synthesis methods, in order to gain information about the star formation histories of these objects. We find that all galaxies of our sample contain an old stellar population (≥1 Gyr) that dominates the stellar mass, and in a great majority of these, we also found evidence for an intermediate-age population ≥100 Myr apart from the presently bursting, ionizing young generation ≤107 yrs.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The nuclear region of the barred spiral galaxy M83 has been imaged at near-infrared wavelengths with the HST NICMOS, showing a new region of star formation activity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html