A5063243695- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- History and Developments in Astronomy
- Cosmology and Gravitation Theories
- Geophysics and Gravity Measurements
- Advanced Fiber Laser Technologies
- Scientific Research and Discoveries
- CCD and CMOS Imaging Sensors
- Pulsars and Gravitational Waves Research
- Solar and Space Plasma Dynamics
- Astrophysical Phenomena and Observations
Louisiana State University
2022-2024
Heidelberg University
2017-2022
Institute of Space Sciences
2018
The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the sample by publishing one spectrum each dwarf. These spectra cover wavelength range 520--1710nm at a resolution of least $R > 80,000$, and measure its RV, H$\alpha$ emission, projected rotation velocity. We an atlas high-resolution M-dwarf compare atmospheric models. To quantify RV precision that can be achieved in low-mass stars over range, analyze our...
Context. Teegarden's Star is the brightest and one of nearest ultra-cool dwarfs in solar neighbourhood. For its late spectral type (M7.0V), star shows relatively little activity a prime target for near-infrared radial velocity surveys such as CARMENES. Aims. As part CARMENES search exoplanets around M dwarfs, we obtained more than 200 radial-velocity measurements analysed them planetary signals. Methods. We find periodic variability velocities Star. also studied photometric to rule out...
Context: The main goal of the CARMENES survey is to find Earth-mass planets around nearby M-dwarf stars. Seven M-dwarfs included in sample had been observed before with HIRES and HARPS either were reported have one short period planetary companion (GJ15A, GJ176, GJ436, GJ536 GJ1148) or are multiple systems (GJ581 GJ876). Aims: We aim report new precise optical radial velocity measurements for these planet hosts test overall capabilities CARMENES. Methods: combined our Doppler those available...
The CARMENES instrument is a pair of high-resolution (R⪆80,000) spectrographs covering the wavelength range from 0.52 to 1.71 μm, optimized for precise radial velocity measurements. It was installed and commissioned at 3.5m telescope Calar Alto observatory in Southern Spain 2015. first large science program survey ~ 300 M dwarfs, which started on Jan 1, 2016. We present an overview all subsystems (front end, fiber system, visible-light spectrograph, near-infrared calibration units, etalons,...
Abstract Strong gravitational lenses provide unique laboratories for cosmological and astrophysical investigations, but they must first be discovered – a task that can met with significant contamination by other objects asterisms. Here we review strong lens searches, covering various sources (quasars, galaxies, supernovae, FRBs, GRBs, GWs), (early- late-type groups, clusters), datasets (imaging, spectra, lightcurves), wavelengths. We present the physical characteristics of source...
The design and construction of CARMENES has been presented at previous SPIE conferences. It is a next-generation radial-velocity instrument the 3.5m telescope Calar Alto Observatory, which was built by consortium eleven Spanish German institutions. consists two separate échelle spectrographs covering wavelength range from 0.52 to 1.71μm spec-tral resolution R < 80,000, fed fibers Cassegrain focus telescope. saw "First Light" on Nov 9, 2015. During commissioning initial operation phases, we...
We report on the first star discovered to host a planet detected by radial velocity (RV) observations obtained within CARMENES survey for exoplanets around M dwarfs. HD 147379 ($V = 8.9$ mag, $M 0.58 \pm 0.08$ M$_{\odot}$), bright M0.0V at distance of 10.7 pc, is found undergo periodic RV variations with semi-amplitude $K 5.1\pm0.4$ m s$^{-1}$ and period $P 86.54\pm0.06$ d. The signal in our data, which were taken between 2016 2017, supported HIRES/Keck that since 2000. are interpreted as...
In November 2019, the nearby single, isolated DQ-type white dwarf LAWD 37 (WD 1142-645) aligned closely with a distant background source and caused an astrometric microlensing event. Leveraging astrometry from \Gaia{} followup data \textit{Hubble Space Telescope} we measure deflection of obtain gravitational mass for LAWD~37. The main challenge this analysis is in extracting lensing signal faint whilst it buried wings LAWD~37's point spread function. Removal 37's function induces significant...
Aims: In this work, we aim to provide a reliable list of gravitational lens (GL) candidates based on search performed over the entire Gaia Data Release 2 (Gaia DR2). We also show that sole astrometric and photometric informations coming from satellite yield sufficient insights for supervised learning methods automatically identify GL with an efficiency is comparable image processing. Methods: simulated 106,623,188 systems composed more than two images, regular grid parameters characterizing...
Quasar strong gravitational lenses are important tools for putting constraints on the dark matter distribution, energy contribution, and Hubble-Lemaître parameter. We aim to present a new supervised machine learning-based method identify these in large astrometric surveys. The Gaia Focused Product Release (FPR) GravLens catalogue is designed identification of multiply imaged quasars, as it provides astrometry photometry all sources field 4.7 million quasars. Our approach automatically...
Context. Strong gravitationally lensed quasars are among the most interesting and useful observable extragalactic phenomena. Because their study constitutes a unique tool in various fields of astronomy, they highly sought, not without difficulty. Indeed, even this era all-sky surveys, recognition remains great challenge, with barely few hundred currently known systems. Aims. In work we aim to detect new strongly quasar candidates recently published Gaia Data Release 2 (DR2), which is highest...
Thanks to its spatial resolution the ESA/Gaia space mission offers a unique opportunity discover new multiply-imaged quasars and study already known lensed systems at sub-milliarcsecond astrometric precisions. In this paper, we address detection of from Gaia Data Release 2 determine photometric properties individually detected images found in DR2 catalogue. We have compiled an exhaustive list quasar gravitational lenses literature search for counterparts 2. then analyze these Gaia's...
Context: Astrometric gravitational microlensing is an excellent tool to determine the mass of stellar objects. Using precise astrometric measurements lensed position a background source in combination with accurate predictions positions lens and unlensed it possible accuracy few percent. Aims: Making use recently published Gaia Data Release 2 (DR2) catalogue, we want predict events caused by foreground stars high proper motion passing coming decades. Methods: We selected roughly 148 000...
Context. Astrometric gravitational microlensing can be used to determine the mass of a single star (the lens) with an accuracy few percent. To do so, precise measurements angular separations between lens and background below 1 milli-arcsecond at different epochs are needed. Hence only most accurate instruments used. However, since timescale is in order months years, astrometric deflection might detected by Gaia, even though each observed on low cadence. Aims. We want show how accurately Gaia...
Abstract Astrometric microlensing is a unique tool to measure stellar masses. It allows us determine the mass of lensing star with an accuracy few percent. In this paper, we update, extend, and refine our predictions astrometric-microlensing events based on Gaia’s early Data release 3 (eDR3). We selected about 500.000 high-proper-motion stars from Gaia eDR3 μ tot > 100 mas yr −1 searched for background sources close their paths. applied various selection criteria cuts in order exclude...