123269674
Accurate Group Delay Measurement for Radial Velocity Instruments Using the Dispersed Fixed Delay Interferometer Method. II. Application of Heterodyne Combs Using an External Interferometer Filter
A fixed delay interferometer is the key component in a DFDI (dispersed fixed delay interferometer) instrument for an exoplanet search using the radial velocity (RV) technique. Although the group delay (GD) of the interferometer can be measured with white light combs (WLCs), the measurement precision is limited by the comb visibility, and the wavelength coverage is constrained by the comb sampling. For instance, this method can calibrate only half of the SDSS-III MARVELS spectra and reach a precision of 2.2 m s-1. This article introduces an innovative method using a sine source for precision delay calibration over very broad wavelengths. The sine source is made of a monolithic Michelson interferometer fed with white light. The interferometer modulated white light (in a sinusoidal form) is fed into a DFDI instrument for calibration. Due to an optimal GD of the sine source, Fourier components from the DFDI interferometer, the sine source, and their frequency beating can be clearly separated and effectively extracted with a chirped Fourier transform to allow precision measurements of the interferometer GD over the entire range of operation wavelengths. The measurements of the MARVELS interferometer with a sine source show that this new calibration method has improved the wavelength coverage by a factor of 2 and the precision by a factor of 3. The RV measurement error induced by GD measurement uncertainties is controlled to be less than 1 m s-1, which has met the requirements for MARVELS moderate-to-high Doppler precision (~5-30 m s-1) for exoplanet search around V ~ 8-12 solar-type stars. Heterodyne combs using an external interferometer source can be applied in other areas of optics measurement and calibration.
118403124
How Close Are We To Detecting Earth-like Planets in the Habitable Zone Using the Radial Velocity Technique?
Discovering an Earth-like exoplanet in habitable zone is an important milestone for astronomers in search of extra-terrestrial life. While the radial velocity (RV) technique remains one the most powerful tools in detecting and characterizing exo-planetary sys- tems, we calculate the uncertainties in precision RV measurements considering stellar spectral quality factors, RV calibration sources, stellar noise and telluric contamination in different observational bandpasses and for different spectral types. We predict the optimal observational bandpass for different spectral types using the RV technique un- der a variety of conditions. We compare the RV signal of an Earth-like planet in the habitable zone (HZ) to the near future state of the art RV precision and attempt to answer the question: How close are we to detecting Earth-like planet in the HZ using the RV technique?
53650794
MARVELS-1: A FACE-ON DOUBLE-LINED BINARY STAR MASQUERADING AS A RESONANT PLANETARY SYSTEM AND CONSIDERATION OF RARE FALSE POSITIVES IN RADIAL VELOCITY PLANET SEARCHES
We have analyzed new and previously published radial velocity (RV) observations of MARVELS-1, known to have an ostensibly substellar companion in a ~6 day orbit. We find significant (~100 m s–1) residuals to the best-fit model for the companion, and these residuals are naively consistent with an interior giant planet with a P = 1.965 days in a nearly perfect 3:1 period commensurability (|Pb /Pc – 3| < 10–4). We have performed several tests for the reality of such a companion, including a dynamical analysis, a search for photometric variability, and a hunt for contaminating stellar spectra. We find many reasons to be critical of a planetary interpretation, including the fact that most of the three-body dynamical solutions are unstable. We find no evidence for transits, and no evidence of stellar photometric variability. We have discovered two apparent companions to MARVELS-1 with adaptive optics imaging at Keck; both are M dwarfs, one is likely bound, and the other is likely a foreground object. We explore false-alarm scenarios inspired by various curiosities in the data. Ultimately, a line profile and bisector analysis lead us to conclude that the ~100 m s–1 residuals are an artifact of spectral contamination from a stellar companion contributing ~15%-30% of the optical light in the system. We conclude that origin of this contamination is the previously detected RV companion to MARVELS-1, which is not, as previously reported, a brown dwarf, but in fact a G dwarf in a face-on orbit.
201802101
APPLICATION OF THE GIGE VISION DIGITAL CAMERA FOR BEAM DIAGNOSTICS IN HLS
Abstract GigE Vision (Gigabit Ethernet vision standard) is a new interface standard for the latest vision of cameras with higher performance compared to analogue vision standard and other digital vision standard. In recent years, the market of industrial vision components is evolving towards GigE Vision. The cameras comply with GigE Vision are capable of providing low distortion for image transmission over long distance with high image rate. This paper will present applications of GigE Vision digital camera for the measurement of beam profile and emittance at the storage ring of HLS (Hefei Light Source).
8075527
A Third Planet Orbiting HIP 14810
We present new precision radial velocities and a three-planet Keplerian orbit fit for the V = 8.5, G5 V star HIP 14810. We began observing this star at Keck Observatory as part of the N2K Planet Search Project. Wright et al. (2007) announced the inner two planets to this system, and subsequent observations have revealed the outer planet planet and the proper orbital solution for the middle planet. The planets have minimum masses of 3.9, 1.3, and 0.6 M_Jup and orbital periods of 6.67, 147.7, and 952 d, respectively. We have numerically integrated the family of orbital solutions consistent with the data and find that they are stable for at least 10^6 yr. Our photometric search shows that the inner planet does not transit.
20026118
The ninth data release of the sloan digital sky survey: first spectroscopic data from the sdss-iiI baryon oscillation spectroscopic survey
The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median z ~ 0.52), 102,100 new quasar spectra (median z ~ 2.32), and 90,897 new stellar spectra, along with the data presented in previous data releases. These spectra were obtained with the new BOSS spectrograph and were taken between 2009 December and 2011 July. In addition, the stellar parameters pipeline, which determines radial velocities, surface temperatures, surface gravities, and metallicities of stars, has been updated and refined with improvements in temperature estimates for stars with T eff -0.5. DR9 includes new stellar parameters for all stars presented in DR8, including stars from SDSS-I and II, as well as those observed as part of the SEGUE-2. The astrometry error introduced in the DR8 imaging catalogs has been corrected in the DR9 data products. The next data release for SDSS-III will be in Summer 2013, which will present the first data from the APOGEE along with another year of data from BOSS, followed by the final SDSS-III data release in 2014 December.
122602751
Application of the complex scaling method in relativistic mean-field theory
We develop the complex scaling method within the framework of the relativistic mean-field (RMF) model. With the self-consistent nuclear potentials from the RMF model, the complex scaling method is used to study single-particle resonant states in spherical nuclei. As examples, the energies and widths of low-lying neutron resonant states in {sup 120}Sn are obtained. The results are compared with those from the real stabilization method, the scattering phase-shift method, and the analytic continuation in the coupling constant approach and satisfactory agreements are found.
14085517
Twisted Gauge Theory Model of Topological Phases in Three Dimensions
We propose an exactly solvable lattice Hamiltonian model of topological phases in $3+1$ dimensions, based on a generic finite group $G$ and a $4$-cocycle $\omega$ over $G$. We show that our model has topologically protected degenerate ground states and obtain the formula of its ground state degeneracy on the $3$-torus. In particular, the ground state spectrum implies the existence of purely three-dimensional looplike quasi-excitations specified by two nontrivial flux indices and one charge index. We also construct other nontrivial topological observables of the model, namely the $SL(3,\mathbb{Z})$ generators as the modular $S$ and $T$ matrices of the ground states, which yield a set of topological quantum numbers classified by $\omega$ and quantities derived from $\omega$. Our model fulfills a Hamiltonian extension of the $3+1$-dimensional Dijkgraaf-Witten topological gauge theory with a gauge group $G$. This work is presented to be accessible for a wide range of physicists and mathematicians.
119969840
First spatial alignment of the LHCb VELO and analysis of beam absorber collision data
A first alignment of the LHCb Vertex Locator has been obtained from beam induced tracks at the LHC. A 450 GeV/c protons were collided on a beam absorber during the LHC synchronisation tests of the anti-clockwise beam in August and September 2008. The resulting particle tracks have been reconstructed by the Vertex Locator. This was the first full reconstruction of tracks induced by the LHC beam. The quality of the data obtained is discussed. A total of 2200 tracks were reconstructed from the full data sample, and a first spatial alignment was obtained. The detector is aligned to an accuracy of Slim in the sensor plane. The results confirm that all detector modules have not been displaced from their surveyed positions by more than 10 mm. (C) 2010 Elsevier B.V. All rights reserved.
6544412
Bunch length measurement in time domain for HLS
A simple measurement method of beam bunch length in time domain for HLS (Hefei Light Source) has been proposed. The bunch length measurement system is composed of an optical system, a high speed photo- receiver and a wide bandwidth oscilloscope. The photo- receiver which is made by FEMTO has high sensitivity and high bandwidth, which converts the synchrotron radiation light into electronic signal. The oscilloscope which is made by Tektronix is TDS7704B, which has a high bandwidth up to 7GHz and show the bunch length in time domain. The measurement results of the bunch length and its analysis are given. We compare the results with that measured by the conventional method using a streak camera.
35215306
Longitudinal Impedance Measurements of the Components for the BEPCII
A longitudinal impedance measurement system was established for the BEPCII. The measurements, done in the frequency domain, are based on the coaxial wire method using HP/Agilent 8720ES network analyzer. The applications of the TRL calibration technique and absorbers were investigated to find a good approach for impedance measurements. The impedance, larger than 20 Ohm and below 6 GHz, can be measured using the TRL calibration technique in the experiment. And better measurement results were got using the reference pipes with the absorbers. So, this system satisfies the requirements of the BEPCII. This paper gives a review on this impedance measurements system for the BEPCII. The measurements results show that there are no serious impedance problems for BEPCII bellows and injection kickers, agreeing well with the numerical simulations. More improvements on this system are in progress.