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The N2K Consortium. VII. Atmospheric Parameters of 1907 Metal-rich Stars: Finding Planet-Search Targets
We report high-precision atmospheric parameters for 1907 stars in theN2K low-resolution spectroscopic survey, designed to identify metal-richFGK dwarfs likely to harbor detectable planets. Of these stars, 284 arein the ideal temperature range for planet searches,Teff<=6000 K, and have a 10% or greater probability ofhosting planets based on their metallicities. The stars in thelow-resolution spectroscopic survey should eventually yield >60 newplanets, including 8-9 hot Jupiters. Short-period planets have alreadybeen discovered orbiting the survey targets HIP 14810 and HD 149143.
| A SCUBA Galaxy in the Protocluster around 53W002 at z=2.4
We analyze an 850 μm Submillimetre Common-User Bolometer Array(SCUBA) map of the environment of the z=2.39 radio galaxy 53W002, whichhas been shown to reside in an overdensity of Lyα-detectedgalaxies. We identify four luminous submillimeter sources within a2.3′ (1.2 Mpc at z=2.39) diameter area around the radio galaxy(which itself is a weak submillimeter source). We employ a 1.4 GHz mapto accurately locate the counterpart of one of these sources, SMMJ17142+5016, and identify this source with a narrow-line active galacticnucleus with an extended Lyα halo at z=2.390 that is a member ofthe structure around 53W002. Hence, SMM J17142+5016 is the firstspectroscopically confirmed submillimeter-selected companion to ahigh-redshift radio galaxy. We discuss the OH-Airglow SuppressionSpectrograph JHK spectrum of this galaxy and in addition present fivenew constraints on its spectral energy distribution longward of 1 μm,using these to estimate its bolometric luminosity as~8×1012 Lsolar, or a star formation rate of~103 Msolar yr-1 if young stars providethe bulk of the luminosity. This result provides direct support for thestatistical detection of overdensities of SCUBA galaxies aroundhigh-redshift radio galaxies and confirms theoretical predictions thatSCUBA galaxies, as the progenitors of massive elliptical galaxies,should be strongly clustered in the highest density regions of thedistant universe.
| JHK Spectra of the z = 2.39 Radio Galaxy 53W002
We present low-resolution, near-IR JHK spectra of the weak Z=2.39 radiogalaxy 53W002, obtained with the OH-airglow Suppressor spectrograph(OHS) and Cooled Infrared Spectrograph and Camera for OHS (CISCO) on theSubaru Telescope. They cover rest-frame wavelengths of3400-7200Å, and the emission lines of [OII]λ3727, Hβ, [OIII] λλ4959, 5007,Hα/Hβ line ratio, we find an extinction of E(B-V)=0.14. Theemission-line ratios are reproduced by a cloud of electron densityne=1×103-4 cm-3 with solar metallicity,ionized by an α = -0.7 power-law continuum with ionizing parameterU = 1 × 10-3. In addition to these emission lines, wemake the first spectroscopic confirmation of the Balmer discontinuity ina high-z radio galaxy. Together with rest-frame UV photometry from theliterature, we show that at least 1/3 of the present stellar mass wasformed in the current starburst. The stellar mass was estimated to be(1-1.4) × 1011Msun by one-component model fitting,which is smaller than that of typical z ~ 1 B2/6C radio galaxies. Wesuggest that 53W002 is currently assembling a large part of its stellarmass through merger events with the surrounding sub-galactic clumps,some of which can be identified with the Lα emitters detected innarrow-band imaging. After a few such events over the next few Gyr,53W002 will evolve into a massive elliptical galaxy.
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| Csillagkép: | Sárkány |
| Rektaszcenzió: | 17h05m56.97s |
| Deklináció: | +52°01'57.1" |
| Vizuális fényesség: | 8.306 |
| Távolság: | 79.491 parszek |
| RA sajátmozgás: | -45.1 |
| Dec sajátmozgás: | -28.1 |
| B-T magnitude: | 8.947 |
| V-T magnitude: | 8.359 |
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