We present an ISO SWS and ISOPHOT-S, mid-infrared spectroscopic survey of 15 ultraluminous IRAS galaxiesWe combine the survey results with a detailed case study, based on arc-(L IR º 1012 L _ ). second resolution, near-IR, and millimeter imaging spectroscopy, of one of the sample galaxies (UGC 5101). We compare the near-and mid-IR characteristics of these ultraluminous galaxies to ISO and literature data of 30 starburst and active galactic nuclei (AGN) template galaxies. We Ðnd the following :

We report D1A resolution K-band (2 km) imaging spectroscopy of the central parsec of our Galaxy. The derived radial velocities for 223 early-and late-type stars probe the nuclear mass distribution to spatial scales of 0.1 pc. We Ðnd a statistically very signiÐcant increase of projected stellar velocity dispersion from about 55 km s~1 at p D 5 pc to 180 km s~1 at p D 0.1 pc. The stars are also rotating about the dynamic center. The late-type stars follow general Galactic rotation, while the early-type stars show counter-rotation. Fitting simultaneously the observed projected surface densities and velocity dispersions, we derive the intrinsic volume densities and radial velocity dispersions as a function of distance from the dynamic center for both types of stars. We then derive the mass distribution between 0.1 and 5 pc from the Jeans equation assuming an isotropic velocity Ðeld. Our analysis requires a compact central dark mass of 2.5È3.2 ] 106 at 6È8 p signiÐcance. The dark mass has a density of 109 pc~3 or M _ , M _ greater and a mass to 2 km luminosity of º 100. The increase in mass-to-luminosity ratio can be reduced but not eliminated even if extreme anisotropic velocity destributions are considered. The dark mass cannot be a cluster of solar mass remnants (such as neutron stars). It is either a compact cluster of 10È20 black holes or a single massive black hole. M _

We report results of a direct imaging survey for giant planets around 80 members of the β Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ∆H=13.9 mag at 1" in combined CH 4 narrowband ADI+SDI 0 mode and median contrasts of ∆H=15.1 mag at 2" in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with NICI all other candidates that lay within 400 AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI campaign followup. Four comoving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36±6 M Jup , 16.4±1.0 AU, Biller et al. 2010) , CD -35 2722B (31±8 M Jup , 67±4 AU, Wahhaj et al. 2011), HD 12894B (0.46±0.08 M ⊙ , 15.7±1.0 AU), and BD+07 1919C (0.20±0.03 M ⊙ , 12.5±1.4 AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-150 AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. Our results strongly constrain the frequency of planets within semi-major axes of 50 AU as well. We restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-50 AU to <21% at a 95.4% confidence level using DUSTY models and to <7% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars.

We report near-infrared integral field spectroscopy of the luminous merging galaxy NGC 6240. Stellar velocities show that the two K-band peaks separated by 1. ′′ 6 are the central parts of inclined, rotating disk galaxies with equal mass bulges. The dynamical masses of the nuclei are much larger than the stellar mass derived from the K-band light, implying that the progenitor galaxies were galaxies with massive bulges. The K-band light is dominated by red supergiants formed in the two nuclei in starbursts, triggered ≈ 2× 10 7 years ago, possibly by the most recent perigalactic approach. Strong feedback effects of a superwind and supernovae are responsible for a short duration burst (≈ 5 × 10 6 years) which is already decaying. The two galaxies form a prograderetrograde rotating system and from the stellar velocity field it seems that one of the two interacting galaxies is subject to a prograde encounter. Between the stellar nuclei is a prominent peak of molecular gas (H 2 , CO). The stellar velocity dispersion peaks there indicating that the gas has formed a local, self-gravitating concentration decoupled from the stellar gravitational potential. NGC 6240 has previously been reported to fit the paradigm of an elliptical galaxy formed through the merger of two galaxies. This was based on the near-infrared light distribution which follows a r 1/4 -law. Our data cast strong doubt on this conclusion: the system is by far not relaxed, rotation plays an important role, as does self-gravitating gas, and the near-infrared light is dominated by young stars.NGC 6240 was observed with the MPE near-infrared imaging spectrograph 3D (Weitzel et al. 1996) in conjunction with the tip-tilt correction adaptive optics system ROGUE (Thatte et al. 1995) in two observing runs. 3D is an integral field spectrograph that simultaneously obtains spectra for each of 256 spatial pixels covering a square field of view with over 95% fill factor. In both observing runs the spectral resolving power (R ≡ λ/∆λ) was 2000 and Nyquist sampled using two settings of a piezo-driven flat mirror.The first observing run took place in April 1996 at the ESO 2.2 m telescope on La Silla, Chile. The pixel scale was 0. ′′ 3 per pixel, and a wavelength range from 2.18µm to 2.45µm was covered. The total on-source integration time was 4600 s with individual frame integration times of 300 s or 400 s. The same amount of time was spent off-source 1 ′ E and W of the nuclear region of NGC 6240 for sky background subtraction. The seeing during the observations was better than 0. ′′ 8.

Abstract. In order to estimate the masses of the compact, young star clusters in the merging galaxy pair, NGC 4038/4039 ("the Antennae"), we have obtained medium and high resolution spectroscopy using ISAAC on VLT-UT1 and UVES on VLT-UT2 of five such clusters. The velocity dispersions were estimated using the stellar absorption features of CO at 2.29 µm and metal absorption lines at around 8500Å, including lines of the Calcium Triplet. The size scales and light profiles were measured from HST images. From these data and assuming Virial equilibrium, we estimated the masses of five clusters. The resulting masses range from 6.5 × 10 5 to 4.7 × 10 6 M . These masses are large, a factor of a few to more than 10 larger than the typical mass of a globular cluster in the Milky Way. The mass-to-light ratios for these clusters in the V-and K-bands in comparison with stellar synthesis models suggest that to first order the IMF slopes are approximately consistent with Salpeter for a mass range of 0.1 to 100 M . However, the clusters show a significant range of possible IMF slopes or lower mass cut-offs and that these variations may correlate with the interstellar environment of the cluster. Comparison with the results of Fokker-Planck simulations of compact clusters with properties similar to the clusters studied here suggest that they are likely to be long-lived and may lose a substantial fraction of their total mass. This mass loss would make the star clusters obtain masses which are comparable to the typical mass of a globular cluster.