We present results on the clustering of 282 068 galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS) sample of massive galaxies with redshifts 0.4 < z < 0.7 which is part of the Sloan ...Digital Sky Survey III project. Our results cover a large range of scales from ~500 to ~90 h... Mpc. We compare these estimates with the expectations of the flat ... cold dark matter (...CDM) standard cosmological model with parameters compatible with Wilkinson Microwave Anisotropy Probe 7 data. We use the MultiDark cosmological simulation, one of the largest N-body runs presently available, together with a simple halo abundance matching technique, to estimate galaxy correlation functions, power spectra, abundance of subhaloes and galaxy biases. We find that the ...CDM model gives a reasonable description to the observed correlation functions at z ... 0.5, which is remarkably good agreement considering that the model, once matched to the observed abundance of BOSS galaxies, does not have any free parameters. However, we find a ...10 per cent deviation in the correlation functions for scales ... 1 and ~10-40 h... Mpc. A more realistic abundance matching model and better statistics from upcoming observations are needed to clarify the situation. We also estimate that about 12 per cent of the 'galaxies' in the abundance-matched sample are satellites inhabiting central haloes with mass ... Using the MultiDark simulation, we also study the real-space halo bias b of the matched catalogue finding that b = 2.00 ± 0.07 at large scales, consistent with the one obtained using the measured BOSS-projected correlation function. Furthermore, the linear large-scale bias, defined using the extrapolated linear matter power spectrum, depends on the number density n of the abundance-matched sample as ... Extrapolating these results to baryon acoustic oscillation scales, we measure a scale-dependent damping of the acoustic signal produced by non-linear evolution that leads to ~2-4 per cent dips at ... level for wavenumbers ... in the linear large-scale bias. (ProQuest: ... denotes formulae/symbols omitted.)
We present results on the clustering of 282 068 galaxies in the Baryon Oscillation Spectroscopic Survey (BOSS) sample of massive galaxies with redshifts 0.4 < z < 0.7 which is part of the Sloan ...Digital Sky Survey III project. Our results cover a large range of scales from ∼500 to ∼90 h
−1 Mpc. We compare these estimates with the expectations of the flat Λ cold dark matter (ΛCDM) standard cosmological model with parameters compatible with Wilkinson Microwave Anisotropy Probe 7 data. We use the MultiDark cosmological simulation, one of the largest N-body runs presently available, together with a simple halo abundance matching technique, to estimate galaxy correlation functions, power spectra, abundance of subhaloes and galaxy biases. We find that the ΛCDM model gives a reasonable description to the observed correlation functions at z 0.5, which is remarkably good agreement considering that the model, once matched to the observed abundance of BOSS galaxies, does not have any free parameters. However, we find a 10 per cent deviation in the correlation functions for scales 1 and ∼10-40 h
−1 Mpc. A more realistic abundance matching model and better statistics from upcoming observations are needed to clarify the situation. We also estimate that about 12 per cent of the 'galaxies' in the abundance-matched sample are satellites inhabiting central haloes with mass M 1014 h
−1 M. Using the MultiDark simulation, we also study the real-space halo bias b of the matched catalogue finding that b = 2.00 ± 0.07 at large scales, consistent with the one obtained using the measured BOSS-projected correlation function. Furthermore, the linear large-scale bias, defined using the extrapolated linear matter power spectrum, depends on the number density n of the abundance-matched sample as b = −0.048 − (0.594 ± 0.02)log10(n/ h
3 Mpc−3). Extrapolating these results to baryon acoustic oscillation scales, we measure a scale-dependent damping of the acoustic signal produced by non-linear evolution that leads to ∼2-4 per cent dips at 3σ level for wavenumbers k 0.1 h Mpc−1 in the linear large-scale bias.
We report the discovery of a low-mass companion orbiting the metal-rich, main sequence F star TYC 2949-00557-1 during the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS) pilot ...project. The host star has an effective temperature T{sub eff} = 6135 {+-} 40 K, logg = 4.4 {+-} 0.1, and Fe/H = 0.32 {+-} 0.01, indicating a mass of M = 1.25 {+-} 0.09 M{sub sun} and R = 1.15 {+-} 0.15 R{sub sun}. The companion has an orbital period of 5.69449 {+-} 0.00023 days and straddles the hydrogen burning limit with a minimum mass of 64 M{sub J} , and thus may be an example of the rare class of brown dwarfs orbiting at distances comparable to those of 'Hot Jupiters'. We present relative photometry that demonstrates that the host star is photometrically stable at the few millimagnitude level on time scales of hours to years, and rules out transits for a companion of radius {approx}>0.8 R{sub J} at the 95% confidence level. Tidal analysis of the system suggests that the star and companion are likely in a double synchronous state where both rotational and orbital synchronization have been achieved. This is the first low-mass companion detected with a multi-object, dispersed, fixed-delay interferometer.
We describe the discovery of a likely brown dwarf (BD) companion with a minimum mass of 31.7 + or - 2.0 M sub(Jup) to GSC 03546-01452 from the MARVELS radial velocity survey, which we designate as ...MARVELS-6b. For reasonable priors, our analysis gives a probability of 72% that MARVELS-6b has a mass below the hydrogen-burning limit of 0.072 M sub(odot), and thus it is a high-confidence BD companion. It has a moderately long orbital period of 47.8929 super(+0.0063) sub(-0.0062) days with a low eccentricity of 0.1442 super(+0.0078) sub(-0.0073) and a semi-amplitude of 1644 super(+12) sub(-13) m s super(-1). Moderate resolution spectroscopy of the host star has determined the following parameters: T sub(eff) = 5598 + or - 63, log g = 4.44 + or - 0.17, and Fe/H = +0.40 + or - 0.09. Based upon these measurements, GSC 03546-01452 has a probable mass and radius of M sub(*) = 1.11 + or - 0.11 M sub(odot) and R sub(*) = 1.06 + or - 0.23 Rodot with an age consistent with less than ~6 Gyr at a distance of 219 + or - 21 pc from the Sun. Although MARVELS-6b is not observed to transit, we cannot definitively rule out a transiting configuration based on our observations. There is a visual companion detected with Lucky Imaging at 7".7 from the host star, but our analysis shows that it is not bound to this system. The minimum mass of MARVELS-6b exists at the minimum of the mass functions for both stars and planets, making this a rare object even compared to other BDs. It also exists in an underdense region in both period/eccentricity and metallicity/eccentricity space.
We report the discovery of a candidate brown dwarf (BD) or a very low mass stellar companion (MARVELS-5b) to the star HIP 67526 from the Multi-object Apache point observatory Radial Velocity ...Exoplanet Large-area Survey (MARVELS). The radial velocity curve for this object contains 31 epochs spread over 2.5 yr. Our Kepierian fit, using a Markov Chain Monte Carlo approach, reveals that the companion has an orbital period of 90.2695 super(+0.0188) sub(0.0187) days, an eccentricity of 0.4375 + or - 0.0040, and a semi-amplitude of 2948.14 super(+16.65) sub(-16.55) m s super(-1). Using additional high-resolution spectroscopy, we find the host star has an effective temperature T sub(eff) = 6004 + or - 34 K, a surface gravity log g (cgs) = 4.55 + or - 0.17, and a metallicity Fe/H = +0.04 + or - 0.06. The stellar mass and radius determined through the empirical relationship of Torres et al. yields 1.10 + or - 0.09 M sub(odot) and 0.92 + or - 0.19 R sub(odot). The minimum mass of MARVELS-5b is 65.0 + or - 2.9 M sub(Jup), indicating that it is likely to be either a BD or a very low mass star, thus occupying a relatively sparsely populated region of the mass function of companions to solar-type stars. The distance to this system is 101 + or - 10 pc from the astrometric measurements of Hipparcos. No stellar tertiary is detected in the high-contrast images taken by either FastCam lucky imaging or Keck adaptive optics imaging, ruling out any star with mass greater than 0.2 M sub(odot) at a separation larger than 40 AU.
TYC 4110-01037-1 has a low-mass stellar companion, whose small mass ratio and short orbital period are atypical among binary systems with solar-like (T sub(eff) <, ~ 6000 K) primary stars. Our ...analysis of TYC 4110-01037-1 reveals it to be a moderately aged (<, ~5 Gyr) solar-like star having a mass of 1.07 + or - 0.08 M sub(middot in a circle) and radius of 0.99 + or - 0.18 Re. We analyze 32 radial velocity (RV) measurements from the SDSS-III MARVELS survey as well as 6 supporting RV measurements from the SARG spectrograph on the 3.6 m Telescopio Nazionale Galileo telescope obtained over a period of ~2 years. The best Keplerian orbital fit parameters were found to have a period of 78.994 + or - 0.012 days, an eccentricity of 0.1095 + or - 0.0023, and a semi-amplitude of 4199 + or - 11ms super(-1). We determine the minimum companion mass (if sin i = 1) to be 97.7 + or - 5.8 M sub(Jup). The system's companion to host star mass ratio, > or =0.087 + or - 0.003, places it at the lowest end of observed values for short period stellar companions to solar-like (T sub(eff) <, ~ 6000 K) stars. One possible way to create such a system would be if a triple-component stellar multiple broke up into a short period, low q binary during the cluster dispersal phase of its lifetime. A candidate tertiary body has been identified in the system via single-epoch, high contrast imagery. If this object is confirmed to be comoving, we estimate it would be a dM4 star. We present these results in the context of our larger-scale effort to constrain the statistics of low-mass stellar and brown dwarf companions to FGK-type stars via the MARVELS survey.
We describe the discovery of a likely brown dwarf (BD) companion with a minimum mass of 31.7 +/- 2.0 M_Jup to GSC 03546-01452 from the MARVELS radial velocity survey, which we designate as ...MARVELS-6b. For reasonable priors, our analysis gives a probability of 72% that MARVELS-6b has a mass below the hydrogen-burning limit of 0.072 M_Sun, and thus it is a high-confidence BD companion. It has a moderately long orbital period of 47.8929 +0.0063/-0.0062 days with a low eccentricty of 0.1442 +0.0078/-0.0073, and a semi-amplitude of 1644 +12/-13 m/s. Moderate resolution spectroscopy of the host star has determined the following parameters: T_eff = 5598 +/- 63, log g = 4.44 +/- 0.17, and Fe/H = +0.40 +/- 0.09. Based upon these measurements, GSC 03546-01452 has a probable mass and radius of M_star = 1.11 +/- 0.11 M_Sun and R_star = 1.06 +/- 0.23 R_Sun with an age consistent with less than ~6 Gyr at a distance of 219 +/- 21 pc from the Sun. Although MARVELS-6b is not observed to transit, we cannot definitively rule out a transiting configuration based on our observations. There is a visual companion detected with Lucky Imaging at 7.7 arcsec from the host star, but our analysis shows that it is not bound to this system. The minimum mass of MARVELS-6b exists at the minimum of the mass functions for both stars and planets, making this a rare object even compared to other BDs.
We report the discovery of a candidate brown dwarf or a very low mass stellar companion (MARVELS-5b) to the star HIP 67526 from the Multi-object APO Radial Velocity Exoplanet Large-area Survey ...(MARVELS). The radial velocity curve for this object contains 31 epochs spread over 2.5 years. Our Keplerian fit using a Markov Chain Monte Carlo approach, reveals that the companion has an orbital period of \(90.2695^{+0.0188}_{-0.0187}\) days, an eccentricity of \(0.4375 \pm 0.0040\) and a semi-amplitude of \(2948.14^{+16.65}_{-16.55}\) m s\(^{-1}\). Using additional high-resolution spectroscopy, we find the host star has an effective temperature \(T_{\rm{eff}}=6004 \pm 34\) K, a surface gravity \(\log g\) cgs \(=4.55 \pm 0.17\) and a metallicity Fe/H \(=+0.04 \pm 0.06\). The stellar mass and radius determined through the empirical relationship of Torres et al. (2010), yields 1.10\(\pm\)0.09 \(M_{\sun}\) and 0.92\(\pm\)0.19 \(R_{\sun}\). The minimum mass of MARVELS-5b is \(65.0 \pm 2.9 M_{Jup}\), indicating that it is likely to be either a brown dwarf or a very low mass star, thus occupying a relatively sparsely-populated region of the mass function of companions to solar-type stars. The distance to this system is 101\(\pm\)10 pc from the astrometric measurements of Hipparcos. No stellar tertiary is detected in the high-contrast images taken by either FastCam lucky imaging or Keck adaptive optics imaging, ruling out any star with mass greater than 0.2\(M_{\sun}\) at a separation larger than 40 AU.
PDF
