Andrew Szentgyorgyi
A5036754055- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Advanced Fiber Laser Technologies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Advanced Frequency and Time Standards
- Astrophysical Phenomena and Observations
- Spectroscopy and Laser Applications
- Planetary Science and Exploration
- Advanced Fiber Optic Sensors
- Advanced Measurement and Metrology Techniques
- Photonic and Optical Devices
- Geomagnetism and Paleomagnetism Studies
- Photonic Crystal and Fiber Optics
- Molecular Spectroscopy and Structure
- Laser-Matter Interactions and Applications
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Scientific Measurement and Uncertainty Evaluation
- Galaxies: Formation, Evolution, Phenomena
- Pulsars and Gravitational Waves Research
Center for Astrophysics Harvard & Smithsonian
2015-2024
Smithsonian Astrophysical Observatory
1993-2024
Harvard University
1994-2024
Harvard University Press
2003-2011
CFA Institute
2009
Columbia University
1988-1990
University of Wisconsin–Madison
1987
The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA launch in 2017 as an Astrophysics Explorer mission. spacecraft be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with I = 4-13 temporary drops brightness caused planetary transits. Each star observed interval...
The Transiting Exoplanet Survey Satellite (TESS ) will search for planets transiting bright and nearby stars. TESS has been selected by NASA launch in 2017 as an Astrophysics Explorer mission. spacecraft be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with I<sub>C</sub> (approximately less than) 13 temporary drops brightness caused planetary...
We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains largest number homogeneously observed reduced nearby SNe Ia (z ≲ 0.08) published to date. It more than doubles sample, bringing SN cosmology point where systematic uncertainties dominate. Our natural system has a precision ≲0.02 mag in BVRIr'i' ≲0.04...
The Telescopio Nazionale Galileo (TNG)[9] hosts, starting in April 2012, the visible spectrograph HARPS-N. It is based on design of its predecessor working at ESO's 3.6m telescope, achieving unprecedented results radial velocity measurements extrasolar planetary systems. spectrograph's ultra-stable environment, a temperature-controlled vacuum chamber, will allow under 1 m/s which enable characterization rocky, Earth-like planets. Enhancements from original HARPS include better scrambling...
The Hectospec is a 300 optical fiber fed spectrograph commissioned at the MMT in spring of 2004. In configuration pioneered by Autofib instrument Anglo‐Australian Telescope, Hectospec's probes are arranged radial "fisherman on pond" geometry and held position with small magnets. A pair high‐speed, six‐axis robots move buttons between observing configurations within ∼300 s, to an accuracy ∼25 μm. fibers run for 26 m MMT's focal surface bench spectrograph, operating R∼1000–2000. Hectochelle,...
We present UBVRI photometry of 44 Type Ia supernovae (SNe Ia) observed from 1997 to 2001 as part a continuing monitoring campaign at the Fred Lawrence Whipple Observatory Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is largest homogeneously reduced sample SNe date, nearly doubling number well-observed, nearby with published multicolor CCD light curves. large U-band unique addition, important connections high redshift. decline rate SN curves...
We present the discovery of KELT-1b, first transiting low-mass companion from wide-field Kilodegree Extremely Little Telescope-North (KELT-North) survey. The V=10.7 primary is a mildly evolved, solar-metallicity, mid-F star. brown dwarf or super-massive planet with mass 27.23+/-0.50 MJ and radius 1.110+0.037-0.024 RJ, on very short period (P=1.21750007) circular orbit. KELT-1b receives large amount stellar insolation, an equilibrium temperature assuming zero albedo perfect redistribution...
We present rotation periods for 71 single dwarf members of the open cluster NGC6811 determined using photometry from NASA's Kepler Mission. The results are first Cluster Study which combine Kepler's with ground-based spectroscopy membership and binarity. delineate a tight sequence in color-period diagram ~1 day at mid-F to ~11 days early-K spectral type. This result extends Gyr similar prior ~600 Myr Hyades Praesepe clusters, suggesting that cool stars well-defined surface 3-dimensional...
The Second Workshop on Extreme Precision Radial Velocities defined circa 2015 the state of art Doppler precision and identified critical path challenges for reaching 10 cm s−1 measurement precision. presentations discussion key issues instrumentation data analysis workshop recommendations achieving this bold are summarized here. Beginning with High Accuracy Velocity Planet Searcher spectrograph, technological advances radial velocity (RV) measurements have focused building extremely stable...
We determine the distance to open cluster NGC 2264 using a statistical analysis of member inclinations. derive distance-dependent values sin i (where is inclination angle) for 97 stars in from rotation periods, luminosities, effective temperatures, and projected equatorial velocities, v i, measured these stars. have 96 our sample by analyzing high-resolution spectra with cross-correlation technique. model observed distribution assuming that random axial orientations adopting prescriptions...
We present multi-band optical photometry of 94 spectroscopically confirmed Type Ia supernovae (SNe Ia) in the redshift range 0.0055–0.073, obtained between 2006 and 2011. There are a total 5522 light-curve points. show that our natural-system SN has precision ≲ 0.03 mag BVr'i', 0.06 u', 0.07 U for points brighter than 17.5 estimate it systematic uncertainty 0.014, 0.010, 0.012, 0.046, 0.073 BVr'i'u'U, respectively. Comparisons standard-system with published light curves comparison stars...
We present the discovery of two giant planets orbiting stars in Praesepe (also known as Beehive Cluster). These are first hot Jupiters an open cluster and only to orbit Sun-like, main-sequence a cluster. The detected from Doppler shifted radial velocities; line bisector spans activity indices show no correlation with orbital phase, confirming variations caused by planetary companions. Pr0201b orbits V=10.52 late F dwarf period 4.4264 +/- 0.0070 days has minimum mass 0.540 0.039 Mjup, Pr0211b...
Radial velocity (RV) perturbations induced by stellar surface inhomogeneities including spots, plages and granules currently limit the detection of Earth-twins using Doppler spectroscopy. Such noise is poorly understood for stars other than Sun because their unresolved. In particular, effects on observed radial velocities are extremely difficult to characterize, thus developing optimal correction techniques extract true challenging. this paper, we present preliminary results a solar...
Kepler-93b is a 1.478 +/- 0.019 Earth radius planet with 4.7 day period around bright (V=10.2), astroseismically-characterized host star mass of 0.911+/-0.033 solar masses and 0.919+/-0.011 radii. Based on 86 radial velocity observations obtained the HARPS-N spectrograph Telescopio Nazionale Galileo 32 archival Keck/HIRES observations, we present precise estimate 4.02+/-0.68 masses. The corresponding high density 6.88+/-1.18 g/cc consistent rocky composition primarily iron magnesium...
We have obtained 1087 NIR (JHKs) measurements of 21 SNe Ia using PAIRITEL, nearly doubling the number well-sampled SN light curves. These data strengthen evidence that are excellent standard candles in NIR, even without correction for optical light-curve shape. construct fiducial templates normal from our sample, excluding only three known peculiar Ia: 2005bl, 2005hk, and 2005ke. The H-band absolute magnitudes this sample 18 an intrinsic rms 0.15 mag with no found a relationship between...
Kepler-10b was the first rocky planet detected by Kepler satellite and con- firmed with radial velocity follow-up observations from Keck-HIRES. The mass of measured a precision around 30%, which insufficient to constrain models its internal structure composition in detail. In addition Kepler-10b, second transiting same star period 45 days sta- tistically validated, but velocities were only good enough set an upper limit 20 Mearth for Kepler-10c. To improve on b, HARPS-N Collaboration decided...
We report the discovery of first hot Jupiter in Hyades open cluster. HD 285507b orbits a V = 10.47 K4.5V dwarf (M* 0.734 M☉; R* 0.656 R☉) slightly eccentric () orbit with period days. The induced stellar radial velocity corresponds to minimum companion mass MPsin i 0.917 ± 0.033 MJup. Line bisector spans and activity measures show no correlation orbital phase, amplitude is independent wavelength, supporting conclusion that variations are caused by planetary companion. Follow-up photometry...
The time-variable velocity fields of solar-type stars limit the precision radial-velocity determinations their planets' masses, obstructing detection Earth twins. Since 2015 July we have been monitoring disc-integrated sunlight in daytime using a purpose-built solar telescope and fibre feed to HARPS-N stellar spectrometer. We present analyse measurements cross-correlation function (CCF) parameters obtained first 3 years observation, interpreting them context spatially-resolved observations....
Abstract Modern theories of galaxy formation predict that the Galactic stellar halo was hierarchically assembled from accretion and disruption smaller systems. This hierarchical assembly is expected to produce a high degree structure in combined phase chemistry space; this should provide relatively direct probe history our Galaxy. Revealing requires precise 3D positions (including distances), velocities, for large samples stars. The Gaia satellite delivering proper motions parallaxes >1...
Stellar magnetic activity produces time-varying distortions in the photospheric line profiles of solar-type stars. These lead to systematic errors high-precision radial-velocity measurements, which limit efforts discover and measure masses low-mass exoplanets with orbital periods more than a few tens days. We present new data-driven method for separating Doppler shifts dynamical origin from apparent velocity variations arising variability-induced changes stellar spectrum. show that...
Quaoar is a classical Trans-Neptunian Object (TNO) with an area equivalent diameter of 1,100 km and orbital semi-major axis 43.3 astronomical units. Based on stellar occultations observed between 2018 2021, inhomogeneous ring (Q1R, Quaoar's first ring) was detected around this body. Aims. A new occultation by August 9th, 2022 aiming to improve shape models the physical parameters Q1R while searching for additional material Methods. The provided nine effective chords across Quaoar, pinning...
We present results from 1351 high resolution spectra of 1215 stars in the Orion Nebula Cluster (ONC) and surrounding 1c association, obtained with Hectochelle multiobject echelle spectrograph on 6.5m MMT. confirmed 1111 as members, based their radial velocity and/or H-alpha emission. The distribution members shows a dispersion 3.1 km/s. found substantial north-south gradient spatially coherent structure distribution, similar to that seen molecular gas region. also identified several binary...
view Abstract Citations (99) References (50) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Astrophysical Implications and Observational Prospects of X-Ray Polarimetry Meszaros, P. ; Novick, R. Szentgyorgyi, A. Chanan, G. Weisskopf, M. C. X-ray polarimetry is a prime tool for investigating the physics compact objects, which has not been adequately exploited thus far. However, current low-cost technology modest launch requirements could provide large number...