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The SPIDER experiment, part of the Neutral Beam Test Facility (NBTF) at Consorzio RFX (Padua, Italy), is the prototype of the negative ion source for the ITER neutral beam injectors; the source is coupled to a 100 kV three-grid acceleration system. A Beam Emission Spectroscopy (BES) diagnostic was installed in SPIDER to study and optimize energy distribution, aiming, uniformity and divergence of the H-/D- beam extracted from the source. The diagnostic is based on the analysis of the Doppler shifted H{\alpha}/D{\alpha} light emitted in the interaction between the beam particles and the H2/D2 molecules of the background. In 2019 the BES diagnostic in SPIDER was installed and calibrated, and it allowed to characterize the first hydrogen beams extracted from the SPIDER source, in cesium free conditions. The number of active beamlets composing the beam was reduced from 1280 to 80, affecting the BES diagnostic capabilities. This paper presents the BES diagnostic setup and discusses the first collected results. Under limited extracted current density ($\sim$ 10 A/m^2) and ion energy ($\leq$35 keV), no significant vertical beam deflection caused by the magnetic filter field in the source was detected. In some cases the beamlets were observed to be elongated in horizontal direction; beamlet divergence values down to 20 mrad and 30 mrad e-folding were measured in vertical and horizontal direction, respectively; the intensity of the Doppler shifted radiation was found to be strongly correlated to the beam current and to the beam divergence. The progressive compensation of beamlet deflections (caused by electron suppression filter fields) with increasing voltage in the extraction gap was studied., Comment: 21 pages, 8 figures. Accepted manuscript of a published paper

The SMOLA open magnetic trap was created at the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences (BINP SB RAS) for studying the physics of suppression of plasma longitudinal losses from the system in which rotating plasma is confined in a magnetic field with helicoidal symmetry. The possibility of controlling the plasma rotation velocity is crucial in this concept. Methods of spectroscopic and magnetic diagnostics that allowed obtaining parameters of plasma rotation in the experiments are described. The angular plasma rotation velocity was found to be (0.5–1) × 106 s–1 in different regimes of system operation. The dependences of angular plasma rotation velocity on various parameters of the experiment are discussed.

Slides presented at the Exoplanets Astrostatistics Summer School (12-16 Sept. 2022in Geneva). The presentation introduces Gaussian processes, and outlines several exoplanet-focused applications.

Sub-Doppler resonances in caesium vapours are studied in a laser field produced by counterpropagating two-frequency light beams with mutually orthogonal linear polarisations. The beams are in resonance with optical transitions in the D1 line, the frequency difference of the field spectral components being equal to the hyperfine ground-state splitting in the Cs atom (∼9.2 GHz). It has already been shown that in this configuration, the hypercontrast effect can be observed for sub-Doppler resonances, which makes this configuration promising for the employment in new-generation miniature optical frequency standards. In the present work, two different two-frequency configurations are compared with each other and with the single-frequency configuration widely used in practice for observing saturated absorption resonances. The parameters of nonlinear resonances are measured at various temperatures of caesium vapours and at different optical field intensities. The results of the investigations performed make it possible to find an optimal two-frequency scheme for exciting nonlinear resonances and to estimate a potential of the scheme for its applications in quantum metrology.

A method of sub-Doppler spectroscopy is proposed, based on the peculiarities of narrowing over time of the velocity distribution of optically excited atoms (molecules) of a rarefied gas medium in a thin cell after exposure to a sufficiently short pulse of broadband radiation. Recording of narrow sub-Doppler resonances at the central frequencies of quantum transitions from the atomic state excited by such a pump pulse is carried out by subsequent probe monochromatic light pulses. The optimal conditions for the implementation of this spectroscopy method occur when the radiation decay time of an optically excited atomic level exceeds the characteristic time of flight of atoms between the walls of the thin cell under consideration, the inner thickness of which is many times smaller than its transverse dimensions.

We present the low-resolution transmission spectra of the puffy hot Jupiter HAT-P-65b (0.53 M$_\mathrm{Jup}$, 1.89 R$_\mathrm{Jup}$, $T_\mathrm{eq}=1930$ K), based on two transits observed using the OSIRIS spectrograph on the 10.4 m Gran Telescopio CANARIAS (GTC). The transmission spectra of the two nights are consistent, covering the wavelength range 517--938 nm and consisting of mostly 5 nm spectral bins. We perform equilibrium-chemistry spectral retrieval analyses on the jointly fitted transmission spectrum and obtain an equilibrium temperature of $1645^{+255}_{-244}$ K and a cloud coverage of $36^{+23}_{-17}$%, revealing a relatively clear planetary atmosphere. Based on free-chemistry retrieval, we report strong evidence for TiO. Additional individual analyses in each night reveal weak-to-moderate evidence for TiO in both nights, but moderate evidence for Na or VO only in one of the nights. Future high-resolution Doppler spectroscopy as well as emission observations will help confirm the presence of TiO and constrain its role in shaping the vertical thermal structure of HAT-P-65b's atmosphere., 15 pages, 8 figures, accepted for publication in ApJL

Doppler infrared spectroscopy of intracellular dynamics in living tumor tissue detects speeds down to nanometers per second (10 mHz) and up to microns per second (10 Hz) associated with a full range of cellular processes. Changes in these dynamics have specific Doppler signatures that depend on the applied cancer drugs and the sensitivity of the patient to treatment. However, strong intra-tumor heterogeneity poses a significant challenge to machine-learning classifiers. Here, we describe a Twin Deep Network (TDN) that can be trained to identify these signatures in the presence of strong heterogeneous background to accurately predict patient response to therapy. The TDN is applied to a clinical trial of HER2neg breast-cancer patients undergoing neoadjuvant therapy. This work provides insight into the value of Deep Learning for advanced data analytics as the volume and variety of data from optics-based assays grows.

Emission spectra of neural tungsten (W) sputtered by impact of argon (Ar) ions in a weakly magnetized ( The obtained energy distribution was found in a very good agreement with the Thompson distribution, even though deviations for lower impact energies are observed, e.g. the high-energy tail of sputtered particles demonstrates a faster drop compared to 1/E 2 at energies below 100 eV. Moreover, the standard cosine (Knudsen cosine law) distribution provides a rather good description of emission spectra in the energy range of study. Finally, the energy distribution was also compared with simulations carried out with the binary collision approximation (BCA) based Monte-Carlo code SDTrimSP. It shows a marginally worse description at low energies and better description of the high energy tail compared to the Thompson one. Furthermore, the model was used to determine in-situ the degree of light reflection at the W surface. The results are in excellent agreement with the literature data.

We present a simple experiment to simulate a binary star system to study the Doppler effect using two smartphones and a PC. The smartphones mounted on a rotating bar are used as monochromatic sound sources. A microphone connected to a PC records these signals in the lab frame of reference. The Doppler effect is readily observed, and the experimental results can quantitatively be compared to the expectation of a theoretical model. This experiment can simulate the Doppler Spectroscopy technique used to measure radial velocities and masses in rotating binary stars and the exploration of exoplanets. The set-up is low-cost and simple to construct and understand. The experiment can be carried out at home or in a regular laboratory setting.

The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development at the UC Berkeley Space Sciences Laboratory for the W.M. Keck Observatory. KPF is designed to characterize exoplanets via Doppler spectroscopy with a goal of a single measurement precision of 0.3 m s-1 or better, however its resolution and stability will enable a wide variety of astrophysical pursuits. Here we provide post-preliminary design review design updates for several subsystems, including: the main spectrometer, the fabrication of the Zerodur optical bench; the data reduction pipeline; fiber agitator; fiber cable design; fiber scrambler; VPH testing results and the exposure meter.

High precision Doppler spectroscopy hinges on an accurate understanding of the wavelength-to-pixel mapping (wavelength solution) of the spectrograph, including particularly systematics related to the detector. Herein, we describe the uniformity and stability of the wavelength solution of the Habitable-zone Planet Finder (HPF), a near-infrared spectrograph that utilizes a Hawaii-2RG (H2RG) hybrid CMOS detector. We focus on time-varying discontinuities equivalent to approximately 10 m/s in the otherwise-smooth wavelength solution, corresponding to the boundaries between H2RG readout channels. This behavior is revealed by calibration with dedicated laser frequency comb and white light-illuminated Fabry-Perot systems over a ~1 year baseline. These findings will inform the usage of similar near-infrared CMOS devices for high-precision applications including Doppler exoplanet and gravitational lensing WFIRST surveys.

Precision Doppler spectroscopy serves as an important tool for Radial Velocity (RV) measurements by observing Doppler shift in the stellar spectrum, which are used for various applications. Passively stabilized Fabry-Perot (FP) etalon based wavelength calibration is one of the techniques used for Doppler spectroscopy. The FP is kept in a pressure and temperature-stabilized environment for it to produce equispaced transmission lines. Since the FP is stable and the line shape is invariant across wavelength pass band, they can be used to determine the spectrograph’s instrumental artifacts and hence analyze spectrograph performance. Knowledge of instrument effects also helps in better prediction of the wavelength calibration model for the spectrograph. We have tested a passively stabilized FP on Vainu Bappu Telescope (VBT) Echelle spectrograph and Hanle Echelle spectrograph (HESP) and observed field curvature and distortion in both. We are analyzing the artifacts introduced and correcting for the same using image processing methods to compensate for the same in wavelength calibration model developed for the FP-based calibrator.

The Macquarie University campus observatory has recently undergone a significant upgrade, with a new fully- automated 0.6 m telescope and on-site facilities including an instrumentation laboratory. Here we report on the design, assembly, and first on-sky tests of a new high-resolution echelle spectrograph for the observatory. This spectrograph will be a key resource at our campus observatory, providing high fidelity measurements that will enable future research, in particular Master and PhD theses that require stellar spectroscopy or radial velocity measurements. The instrument will also form a cornerstone of the laboratory components of the undergraduate astronomy degree, and together with the new 0.6 m telescope, a key tool for project-based learning at the campus observatory. The instrument has been developed with radial velocity precision as the driving metric, and with future work on the environmental stabilisation it is expected to reach a radial velocity precision of 3 m s−1, enabling the observation of a wide range of exoplanets.

Ion Doppler Spectroscopy (IDS) is a diagnostic technique that measures plasma ion temperature and velocity without perturbing the plasma with a physical probe. The ZaP-HD Flow Z-Pinch Experiment at the University of Washington uses this technique to resolve radial temperature and velocity profiles of a Z-pinch plasma. The pinch lifetime is ∼100 µs; therefore, diagnostics capable of sub-microsecond resolution are required to measure the evolution of temperature and velocity profiles. The previous IDS diagnostic system was only capable of collecting a single measurement during a plasma pulse. An improved system has been developed to measure the radially resolved ion temperature and velocity for the entire Z-pinch lifetime. A Kirana 05M ultra-fast framing camera and Specialized Imaging lens ultraviolet intensifier are used to record up to 100 spectra per plasma pulse. The temperature is computed from Doppler broadening of the carbon-III (229.687 nm) impurity ion radiation, and the velocity is computed from the Doppler shift of carbon-III. Measurements are able to resolve the evolution of the ion temperature and velocity over the course of a plasma pulse. The diagnostic has significantly reduced the number of pulses required and provides a more coherent measurement of plasma dynamics than the previous system.

Using a magnetic mirror plasma device, helium ion temperatures were investigated using high resolution Doppler spectroscopy of the He II line at 468.6 nm. The objective was to improve the quality of fits to Langmuir probe data. Measured temperatures, which represent an average value over a line of sight, ranged from 0.07 eV to 0.32 eV with higher values reached in stronger magnetic fields. An analytic expression for the line of sight integral of a variable width Gaussian signal is presented, and it is demonstrated that the integrated signal can, in practice, be accurately fitted by a single Gaussian line shape. A large number of spectra was acquired using a randomized experimental design with four independently controllable engineering variables and three discrete magnetic fields. Separate parameterizations of the results for each magnetic field in terms of the engineering variables showed that the data could already be well fitted using only the plasma current as a predictor. The fit to the ion temperature data was significantly improved when both the plasma current and filament bias voltage were used as predictors. The helium gas fill pressure had negligible predictive value for the ion temperature.

Motions inside living tissues are ubiquitous signatures of the active processes involved in the maintenance of cellular function and health. An innovative label-free non-invasive imaging technology called Biodynamic Imaging (BDI), based on low-coherence interferometry and digital holography, captures intracellular dynamics through ultra-low-frequency Doppler spectra encoding a broad range of cellular and subcellular motions. Clinical trials of BDI assessing patient response to therapy are underway in human ovarian, esophageal and breast cancers.

Precise wavelength calibration is a critical issue for high-resolution spectroscopic observations. The ideal calibration source should be able to provide a very stable and dense grid of evenly distributed spectral lines of constant intensity. A new method which satisfies all mentioned conditions has been developed by our group. The approach is to actively measure the exact position of a single spectral line of a Fabry-Perot etalon with very high precision with a wavelength-tuneable laser and compare it to an extremely stable wavelength standard. The ideal choice of standard is the D2 absorption line of Rubidium, which has been used as an optical frequency standard for decades. With this technique, the problem of stable wavelength calibration of spectrographs becomes a problem of how reliably we can measure and anchor one etalon line to the Rb transition. In this work we present our self-built module for Rb saturated absorption spectroscopy and discuss its stability., SPIE ANZCOP conference, Melbourne 2019

Optical spectroscopy has been and remains an important feature of astrophysical research. Huge telescopes are being built to collect radiation from the most distant stars in the Universe for subsequent study with unique astronomical spectrographs. The fundamental problem to be faced here is that of transferring the extremely weak radiation focused by a moving telescope to the entrance of a stationary spectrograph. The solution is to connect a telescope to a spectrograph through an optical fiber, and research and development of the system's necessary components is currently a major task in the field of fiber optics. A key problem in astronomical spectroscopy is the precision measurement of Doppler line shifts in the spectra of stars to determine the velocity of a star movement along the observation line (ray velocity, RV). A remarkable feature of Doppler spectroscopy is that a precision measurement of quite small RV variations (in fact, accelerations) can last for long periods of time. Such star RV variations can be due, for example, to a planet orbiting the star; the action of the planet causes periodical changes in the motion of the star, thus leading to a Doppler shift of the star's spectrum. The precise measurement of this shift has provided an indirect method for searching for and discovering planets outside the Solar System (exoplanets). The important particular problem of searching for habitable earthlike exoplanets requires a spectral measurement accuracy sufficient to detect RV variations at the level of a few centimeters per second per year. Ten to fifteen years of such measurements would provide a direct estimate of the hypothetical accelerated expansion of the Universe. However, the accuracy required for this is more than conventional spectroscopy techniques (iodine cell and spectral lamps) are capable of. This paper reviews approaches to radically improving Doppler spectroscopy techniques to achieve the required shift measurement accuracy. These approaches include the development of fiber-optic systems for connecting the telescope with the astronomical spectrograph and the development of precision calibrators of astronomical spectrographs based on the advances in laser physics and fiber optics.

High-resolution doppler spectroscopy provides a powerful means for chemical detections in exoplanetary atmospheres. This approach involves monitoring hundreds of molecular lines in the planetary spectrum doppler shifted by the orbital motion of the planet. The molecules are detected by cross-correlating the observed spectrum of the system with a model planetary spectrum. The method has led to molecular detections of H2O, CO, and TiO in hot Jupiters using large ground-based telescopes. Critical to this method, however, is the accurate removal of the stellar and telluric features from the observed spectrum, also known as detrending. Previous molecular detections have relied on specific choices of detrending methods and parameters. However, the robustness of molecular detections across the different choices has not been investigated in detail. We conduct a systematic investigation of the effect of detrending algorithms, parameters, and optimizations on chemical detections using high-resolution spectroscopy. As a case study, we consider the hot Jupiter HD 189733 b. Using multiple methods, we confirm high-significance detections of H2O (4.8$\sigma$) and CO (4.7$\sigma$). Additionally, we report evidence for HCN at high significance (5.0$\sigma$). On the other hand, our results highlight the need for improved metrics and extended observations for robust confirmations of such detections. In particular, we show that detection significances of $\gtrsim$ 4$\sigma$ can be obtained by optimizing detrending at incorrect locations in the planetary velocity space; such false positives can occur in nearly 30\% of cases. We discuss approaches to help distinguish molecular detections from spurious noise., Comment: 15 pages, 16 figures, Accepted for publication in MNRAS

Precise measurements of Doppler shifts of lines in stellar spectra allowing the radial velocity to be measured are an important field of astrophysical studies. A remarkable feature of the Doppler spectroscopy is the possibility to reliably measure quite small variations of the radial velocities (its acceleration, in fact) during long periods of time. Influence of a planet on a star is an example of such a variation. Under the influence of a planet rotating around a star, the latter demonstrates periodic motion manifested in the Doppler shift of the stellar spectrum. Precise measurements of this shift made it possible to indirectly discover planets outside the Solar system (exoplanets). Along with this, searching for Earth-type exoplanets within the habitable zone is an important challenge. For this purpose, accuracy of spectral measurements has to allow one to determine radial velocity variations at the level of centimeters per second during the timespans of about a year. Suchmeasurements on the periods of 10–15 years also would serve as a directmethod for determination of assumed acceleration of the Universe expansion. However, the required accuracy of spectroscopic measurements for this exceeds the possibilities of the traditional spectroscopy (an iodine cell, spectral lamps). Methods of radical improvement of possibilities of astronomical Doppler spectroscopy allowing one to attain the required measurement accuracy of Doppler shifts are considered. The issue of precise calibration can be solved through creating a system of a laser optical frequency generator of an exceptionally high accuracy and stability.

We present measurements of Laser Induced Plasma expansion relying on classical, laterally resolved spectroscopy. Easy observable Doppler splitting of Cu I 324.75 nm spectral line provides measurement of radial expansion velocity in a straightforward way. The measurements are conducted in atmosphere of air, argon and hydrogen at low pressure in the range 20–200 Pa. We found that expansion velocity is linearly decreasing if pressure of surrounding gas increases, with velocity/pressure slope nearly the same for all three gases. Copper atoms have the highest expansion speed in argon ( ∼ 50 km/s) and the smallest speed in air ( ∼ 42 km/s). It is found that expansion velocity increases linearly with irradiance, while intensity of the spectral line is quite insensitive to the laser irradiance.

A compact and low-power complementary metal oxide semiconductor (CMOS)-based transmitter with an operational bandwidth of 90–105 GHz has been deployed as the radiation source in a high-resolution sub-Doppler (Lamb-dip) absorption spectrometer. The source output can be both frequency and amplitude modulated allowing for the application of highly sensitive detection schemes commonly used in molecular spectroscopy. The CMOS transmitter has been shown to have sufficient output power to perform spectral hole burning saturation experiments and a phase-noise floor low enough to determine spectral line positions with a precision of 1 part in 10 $^{\mathbf 9}$ to accuracy within the error of measurements made with traditional millimeter-wave sources.

Toroidal and poloidal flows of injected N+ ions were measured in the high-field side (HFS) scrape-off layer (SOL) of ASDEX Upgrade by Doppler spectroscopy with different degrees of HFS divertor detachment. In high-recycling conditions, the results suggest reversed parallel N+ flow away from the inner divertor in the near SOL close to the separatrix, while the flow is towards the inner divertor throughout the SOL in detached conditions. The measured poloidal N+ flows were directed away from the HFS divertor in the near SOL for all density cases. Divertor plasma oscillations, characterized by momentary peaking of the HFS target ion flux and decrease of the HFS SOL density, were observed slightly before the roll-over of the ion saturation current to the HFS target and lead to an increase in the N+ flow towards the HFS divertor. SOLPS and ERO simulations of the experiment predict entrainment below 50% between the velocities of N+ and D+ ions, suggesting that N+ ions are quantitatively a limited proxy for measuring D+ flows. ERO simulations show significantly higher entrainment for higher ionization states, e.g., N2+ and N3+.

High-resolution Doppler spectroscopy is a powerful tool for identifying molecular species in the atmospheres of both transiting and non-transiting exoplanets. Currently, such data is analysed using cross-correlation techniques to detect the Doppler shifting signal from the orbiting planet. In this paper we demonstrate that, compared to cross-correlation methods currently used, the technique of Doppler tomography has improved sensitivity in detecting the subtle signatures expected from exoplanet atmospheres. This is partly due to the use of a regularizing statistic, which acts to suppress noise, coupled to the fact that all the data is fit simultaneously. In addition, we show that the technique can also effectively suppress contanimating spectral features that may arise due to overlapping lines, repeating line patterns, or the use of incorrect linelists. These issues can confuse conventional cross-correlation approaches, primarily due to aliasing issues inherent in such techniques, whereas Doppler tomography is less susceptible to such effects. In particular, Doppler tomography shows exceptional promise for simultaneously detecting multiple line species (e.g. isotopologues), even when there are high contrasts between such species -- and far outperforms current CCF analyses in this respect. Finally, we demonstrate that Doppler tomography is capable of recovering molecular signals from exoplanets using real data, by confirming the strong detection of CO in the atmosphere of Tau Boo b. We recover a signal with a planetary radial velocity semi-amplitude Kp = 109.6 +/- 2.2 km/s, in excellent agreement with the previously reported value of 110.0 +/- 3.2 km/s., 16 pages, 8 figures, accepted for publication in the Monthly Notices of the Royal Astronomical Society

With the aim of determining the ion direction, Doppler spectroscopy is carried out in a Farnsworth fusor with a spherical cathode grid during star mode operation. The Doppler shift of Balmer-α radiation from excited deuterium atoms (D∗) is analyzed to find the kinetic energy spectrum. Diverging D∗ is measured at a cathode voltage of -20 kV, with currents between 0.5 mA and 3.4 mA, and in the pressure regime of 1.6 Pa-2.6 Pa. D∗ is produced during a charge exchange reaction of fast deuterium ions with the background gas. The measured spectra can only be formed via diverging ions due to momentum conservation during this charge exchange reaction. Dominant blue shifts coming from measurement locations inside microchannels moving toward the observer and red shifted spectra coming from microchannels moving away from the observer prove this diverging ion motion. A kinetic energy distribution of D∗ over different longitudinal positions inside the microchannel is measured at a pressure of (1.7 ± 0.1) Pa. The results indicate an increase in D∗ velocity from the center of the cathode toward the cathode edge. This can be explained by a virtual anode, which accelerates ions created in the center of the cathode outward. These results disagree with the converging ion model but could be explained by the hollow cathode model.

International audience; Dual-frequency sub-Doppler spectroscopy (DF SDS) in vapor cells allows the detection of enhanced-absorption natural-line-width resonances.We investigate here the application of this spectroscopy technique into a Cs micro-fabricated cell. The dependence of the sub-Doppler resonance on the laser intensity is described. The influence of the cell temperature and the retroreflection mirror position was also studied. A preliminary laser beat-note between two 894 nm lasers, each stabilized using DF SDS, demonstrates an Allan deviation lower than 2 × 10 -12 at 1 s and at the level of 10 -12 at 10 2 . Main contributions to the short-term and mid-term stability budget are under study. Latest results will be reported at the conference.

The discovery and characterization of exoplanets around nearby stars are driven by profound scientific questions about the uniqueness of Earth and our solar system, and the conditions under which life could exist elsewhere in our galaxy. Doppler spectroscopy, or the radial velocity (RV) technique, has been used extensively to identify hundreds of exoplanets, but with notable challenges in detecting terrestrial mass planets orbiting within habitable zones. We describe infrared RV spectroscopy at the 10 m Hobby–Eberly Telescope that leverages a 30 GHz electro-optic laser frequency comb with a nanophotonic supercontinuum to calibrate the Habitable Zone Planet Finder spectrograph. Demonstrated instrument precision

LHS 1140 is a nearby mid-M dwarf known to host a temperate rocky super-Earth (LHS 1140 b) on a 24.737-day orbit. Based on photometric observations by MEarth and Spitzer as well as Doppler spectroscopy from HARPS, we report the discovery of an additional transiting rocky companion (LHS 1140 c) with a mass of $1.81\pm0.39~{\rm M_{Earth}}$ and a radius of $1.282\pm0.024~{\rm R_{Earth}}$ on a tighter, 3.77795-day orbit. We also obtain more precise estimates of the mass and radius of LHS 1140 b to be $6.98\pm0.89~{\rm M_{Earth}}$ and $1.727\pm0.032~{\rm R_{Earth}}$. The mean densities of planets b and c are $7.5\pm1.0~\rm{g/cm^3}$ and $4.7\pm1.1~\rm{g/cm^3}$, respectively, both consistent with the Earth's ratio of iron to magnesium silicate. The orbital eccentricities of LHS 1140 b and c are consistent with circular orbits and constrained to be below 0.06 and 0.31, respectively, with 90% confidence. Because the orbits of the two planets are co-planar and because we know from previous analyses of Kepler data that compact systems of small planets orbiting M dwarfs are commonplace, a search for more transiting planets in the LHS 1140 system could be fruitful. LHS 1140 c is one of the few known nearby terrestrial planets whose atmosphere could be studied with the upcoming James Webb Space Telescope., Comment: 22 pages, 8 figures, accepted by AJ

High-resolution Doppler spectroscopy has been used to detect several chemical species in exoplanetary atmospheres. Such detections have traditionally relied on cross correlation of observed spectra against spectral model templates, an approach that is successful for detecting chemical species but not optimised for constraining abundances. Recent work has explored ways to perform atmospheric retrievals on high-resolution spectra (HRS) and combine them with retrievals routinely performed for low-resolution spectra (LRS) by developing a mapping from the cross correlation function to a likelihood metric. We build upon previous studies and report HyDRA-H, a hybrid retrieval code for simultaneous analysis of low- and high- resolution thermal emission spectra of exoplanets in a fully Bayesian approach. We demonstrate HyDRA-H on the hot Jupiter HD 209458b as a case study. We validate our HRS retrieval capability by confirming previous results and report a simultaneous hybrid retrieval using both HRS and LRS data. The LRS data span the HST WFC3 (1.1-1.7 $\mu$m) and Spitzer photometry (IRAC 3.6-8 $\mu$m) bands, while the HRS data were obtained with CRIRES on VLT at 2.3 $\mu$m. The constraints on the composition and temperature profiles for the hybrid retrieval are more stringent than retrievals with either LRS or HRS datasets individually. We retrieve abundances of $\log(\mathrm{H_2O)} = -4.11^{+0.91}_{-0.30}$ and $\log(\mathrm{CO}) = {-2.16}^{+0.99}_{-0.47}$, and $\mathrm{C/O} = 0.99^{+0.01}_{-0.02}$, consistent with previous works. We constrain the photospheric temperature to be $1498^{+216}_{-57}$ K, consistent with the equilibrium temperature. Our results demonstrate the significant advantages of hybrid retrievals by combining strengths of both HRS and LRS observations which probe complementary aspects of exoplanetary atmospheres., Comment: 16 pages, 9 figures, accepted for publication in The Astronomical Journal