• NEANIAS Space Research Community

We have searched, so far in vain, for brown dwarfs or giant planets in the vicinity of several nearby stars using cameras built at Universite de Montreal attached to the CFHT Adaptive Optics system. Here, we show how pairs of images taken simultaneously through separate filters on, and off, the 1.6 micron methane absorption band, can be used to completely defeat speckles, the dominant noise source, while revealing cool brown dwarfs and giant planets in high contrast. We achieve the photon shot-noise limit for data taken without a focal plane mask but, so far, have had less success with data where the image is occulted by a mask. Comment: 10 pages, 7 figures, proceedings of "Astronomy with Adaptive Optics", Sonthofen, Germany

The annihilation of huge quantities of captured dark matter (DM) particles inside low-mass stars has been shown to change some of the stellar properties, such as the star's effective temperature or the way the energy is transported throughout the star. While in the classical picture, without DM, a star of 1 M_sun is expected to have a radiative interior during the main sequence, the same star evolving in a halo of DM with a density rho_x > 10^8 GeV cm^-3 will develop a convective core in order to evacuate the energy from DM annihilation in a more efficient way. This convective core leaves a discontinuity in the density and sound-speed profiles that can be detected by the analysis of the stellar oscillations. In this paper we present an approach towards the use of asteroseismology to detect the signature produced by the presence of DM inside a star, and we propose a new methodology to infer the properties of a DM halo from the stellar oscillations (such as the product of the DM density and the DM particle-nucleon scattering cross-section). Comment: 6 pages, 4 figures. v2 matches published version in MNRAS

The SED of the lensed z=6.56 galaxy HCM6A behind the cluster Abell 370 has been analysed. We find clear indications for the presence of dust in this galaxy, and we estimate the properties of its stellar populations (SFR, age, etc.). From its estimated luminosity, L~(1-4)e.+11 Lsun, this galaxy ranks as a luminous infrared galaxy. This case is then used to examine the detectability of high-z galaxies with Herschel and ALMA. It is evident that with the use of strong gravitational lensing SPIRE/Herschel observations could provide very interesting information on z > 5 galaxies. Strong synergies between ground-based near-IR instruments on 8-10m class telescopes and ELTs, Herschel, the JWST, and ALMA can be expected for the exploration of the first galaxies in the Universe. Comment: To appear in "The Dusty and Molecular Universe: A Prelude to Herschel and ALMA", Eds.: A. Wilson. To be published in ESA Conference Series

The Atacama Large Millimeter/Submillimeter Array (ALMA) is an international effort to construct an instrument capable of matching the exquisite imaging properties of optical space telescopes at millimeter and submillimeter wavelengths. ALMA science will transform our vision of the cold, dusty, and gaseous universe, from extrasolar planets to the youngest galaxies. Comment: 2 pages; Highlights of Astronomy, Volume 14; K.A. van der Hucht, ed

We summarize recent work on the structure and dynamics of the Galactic bar and inner disk. Current work focusses on constructing a quantitative model which integrates NIR photometry, source count observations, gas kinematics, stellar dynamical observations, and microlensing. Some avenues for future research are discussed. Comment: 7 pages, LaTeX, 4 figures. To appear in the Proceedings of Joint Discussion 15, 23rd IAU General Assembly, Highlights of Astronomy Vol.11, ed. J. Andersen. Also available at http://www.astro.unibas.ch/~gerhard/papers/kyoto_jd15.ps.gz

We present the motivation for and the first results from a large radial velocity search for planets around red giants with the 9.2-m Hobby-Eberly Telescope. Comment: 5 pages, to appear in ,,Extreme Solar Systems'', 2007 ASP Conference Series, eds. Debra Fischer, Fred Rasio, Steve Thorsett and Alex Wolszczan

The objective of the PSU/TCfA Search for Planets Around Evolved Stars is to study evolution of planetary systems in the stellar evolution timescale. For such an analysis precise physical parameters of the hosts of the planetary systems are essential. In this paper we present an attempt to obtain basic physical parameters for a sample of evolved stars observed within our survey with the High Resolution Spectrograph of the Hobby-Eberly Telescope. Comment: 2 pages, to appear in "Extreme Solar Systems", 2007 ASP Conference Series, eds. Debra Fischer, Fred Rasio, Steve Thorsett and Alex Wolszczan

We present a new cluster-finding algorithm based on a combination of the Voronoi Tessellation and Friends-Of-Friends methods. The algorithm utilises probability distribution functions derived from a photometric redshift analysis and is tested on simulated cluster-catalogues. We use a 9 band photometric catalogue over 0.5 square degrees in the Subaru XMM-Newton Deep Field. The photometry is comprised of UKIDSS Ultra Deep Survey infrared J and K data combined with 3.6 micro-m and 4.5 micro-m Spitzer bands and optical BVRi'z' imaging from the Subaru Telescope. The cluster catalogue contains 13 clusters at redshifts 0.61 <= z <= 1.39 with luminosities 10L* < L_tot < 50 L*. Comment: 4 pages, 1 figure, To appear in the proceedings of 'At the Edge of the Universe' (9-13 October 2006, Sintra, Portugal)

We describe WHAT, a small-aperture short focal length automated telescope with an 8.2 deg X 8.2 deg field of view, located at the Wise Observatory. The system is aimed at searching for transiting extrasolar planets and variable stars. Preliminary results of 3892 exposures of a single field are presented, where the telescope achieved already a precision of a few mmag for the brightest objects. Additional information can be found at http://wise-obs.tau.ac.il/~what . Comment: 3 pages, 3 figures; to appear in the proceedings of Haute Provence Observatory Colloquium (22-25 August 2005) "Tenth anniversary of 51 Peg-b: Status of and prospects for hot Jupiter studies", ed. L. Arnold, F. Bouchy, & C. Moutou

e present and analyze the correlations between mid-infrared (MIR), far-infrared (FIR), total-infrared (TIR), H$\alpha$, and FUV luminosities for star-forming galaxies, composite galaxies and AGNs, based on a large sample of galaxies selected from the $Spitzer$ SWIRE fields. The MIR luminosities of star-forming galaxies are well correlated with their H$\alpha$, TIR and FUV luminosities, and we re-scaled the MIR-derived SFR formulae according to the above correlations with differences less than 15%. We confirm the recent result by calzetti et al. (2007) that the combined observed H$\alpha$ + 24$\mu$m luminosities L(H$\alpha$$_{\rm obs}$+ 24$\mu$m) possess very tight correlation with the extinction-corrected H$\alpha$ luminosities L(H$\alpha$$\_$corr) for star-forming and even for dwarf galaxies, and show that the combined L(H$\alpha$$_{\rm obs}$+ 8$\mu$m[dust]) are also tightly correlated with L(H$\alpha$$\_$corr) for the above sample galaxies. Among all the L(MIR)-L(FIR) correlations for star-forming galaxies, the L(24$\mu$m) vs. L(70$\mu$m) and L(8$\mu$m[dust]) vs. L(160$\mu$m) are the tightest and also nearly linear. The former could be related to young massive star formation, while the latter might be relevant to diffuse dust emissions heated by old stellar populations. Composite galaxies and AGNs have higher MIR-to-H$\alpha$/MIR-to-FUV luminosity ratios than star-forming galaxies, nevertheless their correlations among MIR, FIR and TIR luminosities are completely following those of star-forming galaxies. Comment: 44 pages, 14 figures; accepted publication in ApJ