Mid-infrared (MIR) spectra observed with Gemini/Michelle were used to study the nuclear region of the Compton-thick Seyfert 2 (Sy 2) galaxy Mrk 3 at a spatial resolution of $sim$200 pc. No polycyclic aromatic hydrocarbons (PAHs) emission bands were d
etected in the N-band spectrum of Mrk 3. However, intense [Ar III] 8.99 $mu$m, [S IV] 10.5 $mu$m and [Ne II] 12.8 $mu$m ionic emission-lines, as well as silicate absorption feature at 9.7$mu$m have been found in the nuclear extraction ($sim$200 pc). We also present subarcsecond-resolution Michelle N-band image of Mrk 3 which resolves its circumnuclear region. This diffuse MIR emission shows up as a wings towards East-West direction closely aligned with the S-shaped of the Narrow Line Region (NLR) observed at optical [O III]$lambda$5007AA image with Hubble/FOC. The nuclear continuum spectrum can be well represented by a theoretical torus spectral energy distribution (SED), suggesting that the nucleus of Mrk 3 may host a dusty toroidal structure predicted by the unified model of active galactic nucleus (AGN). In addition, the hydrogen column density (N$_H,=,4.8^{+3.3}_{-3.1}times,10^{23}$ cm$^{-2}$) estimated with a torus model for Mrk 3 is consistent with the value derived from X-ray spectroscopy. The torus model geometry of Mrk 3 is similar to that of NGC 3281, both Compton-thick galaxies, confirmed through fitting the 9.7$mu$m silicate band profile. This results might provide further evidence that the silicate-rich dust can be associated with the AGN torus and may also be responsible for the absorption observed at X-ray wavelengths in those galaxies.
We present SOAR/OSIRIS cross-dispersed NIR integrated spectra of 12 Galactic globular clusters that are employed to test Maraston (2005, M05) NIR EPS models, and to provide spectral observational constraints to calibrate future models. We measured Ew
of the most prominent NIR absorption features. Optical Ew were also measured. The globular clusters Ew were compared with model predictions with ages within 4-15 Gyr, and metallicities between 1/200 and 2 Zsun. Observed integrated colours were also compared with models. The NIR integrated spectra among our sample appear qualitatively similar in most the absorption features. The M05 models can properly predict the optical Ew observed in globular clusters. Regarding the NIR, they do underestimate the strength of Mg I 1.49mum, but they can reproduce the observed Ew of Fe I 1.58mum, Si I 1.59mum, and CO 2.29mum, in about half of our sample. The remaining objects require the inclusion of intermediate-age populations. Thus, we suggest that the presence of C- and O-rich stars in models is important to reproduce the observed strengths of metallic lines. Another possibility is the lack of alpha-enhancement in the models. In the case of the optical and NIR Fe I lines, standard models and those that include blue horizontal branch stars, produce similar results. A similar trend is observed for Na I 5895A, while in the case of the G-band, the models with blue horizontal branch do describe better the observations. For most of the sample the optical to NIR colours are well described by the M05 models. In general, M05 models can provide reliable information on the NIR stellar population of galaxies, but only when Ew and colours are taken together, in other words, Ew and continuum fluxes should be simultaneously fitted. However, the results should be taken with caution, since the models tend to predict results biased towards young ages.
