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SOXS (Son Of X-Shooter) is a single object spectrograph built by an international consortium for the ESO NTT telescope. SOXS is based on the heritage of the X-Shooter at the ESO-VLT with two arms (UV-VIS and NIR) working in parallel, with a Resolution-Slit product of about 4500, capable of simultaneously observing over the entire band the complete spectral range from the U- to the H-band. SOXS will carry out rapid and long-term Target of Opportunity requests on a variety of astronomical objects. The SOXS vacuum and cryogenic control system has been designed to evacuate, cool down and maintain the UV-VIS detector and the entire NIR spectrograph to their operating temperatures. The design chosen allows the two arms to be operated independently. This paper describes the final design of the cryo-vacuum control system, its functionalities and the tests performed in the integration laboratories., 12 pages, 6 figures, SPIE proceedings of the conference Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV

We report the implemented architecture for monitoring the health and the quality of the Son Of X-Shooter (SOXS) spectrograph for the New Technology Telescope in La Silla at the European Southern Observatory. Briefly, we report on the innovative no-SQL database approach used for storing time-series data that best suits for automatically triggering alarm, and report high-quality graphs on the dashboard to be used by the operation support team. The system is designed to constantly and actively monitor the Key Performance Indicators (KPI) metrics, as much automatically as possible, reducing the overhead on the support and operation teams. Moreover, we will also detail about the interface designed to inject quality checks metrics from the automated SOXS Pipeline (Young et al. 2022).

SOXS (Son Of X-Shooter) is a single object spectrograph offering a simultaneous spectral coverage from U- to H-band, built by an international consortium for the 3.58-m ESO New Technology Telescope at the La Silla Observatory. It is designed to observe all kind of transients and variable sources discovered by different surveys with a highly flexible schedule maintained by the consortium, based on the Target of Opportunity concept. SOXS is going to be a fundamental spectroscopic partner for any kind of imaging survey, becoming one of the premier transient follow-up instruments in the Southern hemisphere. This paper gives an updated status of the project, when the instrument is in the advanced phase of integration and testing in Europe, prior to the activities in Chile., Proc. SPIE 12184, Ground-based and Airborne Instrumentation for Astronomy IX, 121840O (2022)

The Son Of X-Shooter (SOXS) is a single object spectrograph, built by an international consortium for the 3.58-m ESO New Technology Telescope at the La Silla Observatory, ranging from 350 to 2000 nm. In this paper, we present the progress in the AIT phase of the Near InfraRed (NIR) arm. We describe the different AIT phases of the cryo, vacuum, opto-mechanics and detector subsystems, that finally converged at the INAF-OAB premises in Merate (Italy), where the NIR spectrograph is currently being assembled and tested, before the final assembly on SOXS., Comment: 6 pages, 8 Figures, SPIE: Astronomical Telescope + Instrumentation, Montreal 2022

SOXS is the new spectrograph for the ESO NTT telescope able to cover the optical and NIR bands thanks to two different arms: the UV-VIS (350-850 nm), and the NIR (800-2000 nm). In this article, we describe the final design of the visible camera cryostats, the test facilities for the CCD characterization, and the first results with the scientific detector. The UV-VIS detector system is based on a e2v CCD 44-82, a custom detector head coupled with the ESO Continuous Flowing Cryostat (CFC) cooling system and the New General Detector Controller (NGC) developed by ESO. The laboratory facility is based on an optical bench equipped with a Xenon lamp, filter wheels to select the wavelength, an integrating sphere, and a calibrated diode to measure the flux. This paper outlines the visible camera cryostat, the test facilities for the CCD characterization and the first results with the scientific detector in the laboratory and after the integration to the instrument.

This paper reports on the detailed characterisation of the K2-111 planetary system with K2, WASP, and ASAS-SN photometry as well as high-resolution spectroscopic data from HARPS-N and ESPRESSO. The host, K2-111, is confirmed to be a mildly evolved ($\log g=4.17$), iron-poor ([Fe/H]$=-0.46$), but alpha-enhanced ([$\alpha$/Fe]$=0.27$), chromospherically quiet, very old thick disc G2 star. A global fit, performed by using PyORBIT shows that the transiting planet, K2-111b, orbits with a period $P_b=5.3518\pm0.0004$ d, and has a planet radius of $1.82^{+0.11}_{-0.09}$ R$_\oplus$ and a mass of $5.29^{+0.76}_{-0.77}$ M$_\oplus$, resulting in a bulk density slightly lower than that of the Earth. The stellar chemical composition and the planet properties are consistent with K2-111b being a terrestrial planet with an iron core mass fraction lower than the Earth. We announce the existence of a second signal in the radial velocity data that we attribute to a non-transiting planet, K2-111c, with an orbital period of $15.6785\pm 0.0064$ days, orbiting in near-3:1 mean-motion resonance with the transiting planet, and a minimum planet mass of $11.3\pm1.1$ M$_\oplus$. Both planet signals are independently detected in the HARPS-N and ESPRESSO data when fitted separately. There are potentially more planets in this resonant system, but more well-sampled data are required to confirm their presence and physical parameters., Comment: Accepted for publication in MNRAS on 28 Sept 2020. Paper is 18 pages with an additional 12 pages of supplementary material. Data is available at https://vizier.u-strasbg.fr/viz-bin/VizieR?-source=J/MNRAS/499/5004

We present mass and radius measurements of K2-79b and K2-222b, two transiting exoplanets orbiting active G-type stars. Their respective 10.99d and 15.39d orbital periods fall near periods of signals induced by stellar magnetic activity. The two signals might therefore interfere and lead to an inaccurate estimate of exoplanet mass. We present a method to mitigate these effects when radial velocity and activity indicator observations are available over multiple observing seasons and the orbital period of the exoplanet is known. We perform correlation and periodogram analyses on sub-sets composed of each target's two observing seasons, in addition to the full data sets. For both targets, these analyses reveal an optimal season with little to no interference at the orbital period of the known exoplanet. We make a confident mass detection of each exoplanet by confirming agreement between fits to the full radial velocity set and the optimal season. For K2-79b, we measure a mass of 11.8 $\pm$ 3.6 $M_{Earth}$ and a radius of 4.09 $\pm$ 0.17 $R_{Earth}$. For K2-222b, we measure a mass of 8.0 $\pm$ 1.8 $M_{Earth}$ and a radius of 2.35 $\pm$ 0.08 $R_{Earth}$. According to model predictions, K2-79b is a highly irradiated Uranus-analog and K2-222b hosts significant amounts of water ice. We also present an RV solution for a candidate second companion orbiting K2-222 at 147.5d., Comment: 33 pages, 17 figures, 13 tables

The Son Of X-Shooter (SOXS) is a two-channel spectrograph along with imaging capabilities, characterized by a wide spectral coverage (350nm to 2000nm), designed for the NTT telescope at the La Silla Observatory. Its main scientific goal is the spectroscopic follow-up of transients and variable objects. The UV-VIS arm, of the Common Path sub-system, is characterized by the presence of a powered Atmospheric Dispersion Corrector composed (ADC) by two counter-rotating quadruplets, two prisms, and two lenses each. The presence of powered optics in both the optical groups represents an additional challenge in the alignment procedures. We present the characteristics of the ADC, the analysis after receiving the optics from the manufacturer, the emerging issues, the alignment strategies we followed, and the final results of the ADC in dispersion and optical quality.

SOXS (SOn of X-Shooter) is a medium resolution (~4500) wide-band (0.35 - 2.0 {\mu}m) spectrograph which passed the Final Design Review in 2018. The instrument is in the final integration phase and it is planned to be installed at the NTT in La Silla by next year. It is mainly composed of five different optomechanical subsystems (Common Path, NIR spectrograph, UV-VIS spectrograph, Camera, and Calibration) and other mechanical subsystems (Interface flange, Platform, cable corotator, and cooling system). A brief overview of the optomechanical subsystems is presented here as more details can be found in the specific proceedings while a more comprehensive discussion is dedicated to the other mechanical subsystems and the tools needed for the integration of the instrument. Moreover, the results obtained during the acceptance of the various mechanical elements are presented together with the experiments performed to validate the functionality of the subsystems. Finally, the mechanical integration procedure is shown here, along with all the modifications applied to correct the typical problems happening in this phase., Comment: arXiv admin note: text overlap with arXiv:2012.12693

Radial velocity (RV) measurements of transiting multiplanet systems allow us to understand the densities and compositions of planets unlike those in the Solar System. Kepler-102, which consists of 5 tightly packed transiting planets, is a particularly interesting system since it includes a super-Earth (Kepler-102d) and a sub-Neptune-sized planet (Kepler-102e) for which masses can be measured using radial velocities. Previous work found a high density for Kepler-102d, suggesting a composition similar to that of Mercury, while Kepler-102e was found to have a density typical of sub-Neptune size planets; however, Kepler-102 is an active star, which can interfere with RV mass measurements. To better measure the mass of these two planets, we obtained 111 new RVs using Keck/HIRES and TNG/HARPS-N and modeled Kepler-102's activity using quasi-periodic Gaussian Process Regression. For Kepler-102d, we report a mass upper limit of M$_{d} < $5.3 M$_{\oplus}$ [95\% confidence], a best-fit mass of M$_{d}$=2.5 $\pm$ 1.4 M$_{\oplus}$, and a density of $\rho_{d}$=5.6 $\pm$ 3.2 g/cm$^{3}$ which is consistent with a rocky composition similar in density to the Earth. For Kepler-102e we report a mass of M$_{e}$=4.7 $\pm$ 1.7 M$_{\oplus}$ and a density of $\rho_{e}$=1.8 $\pm$ 0.7 g/cm$^{3}$. These measurements suggest that Kepler-102e has a rocky core with a thick gaseous envelope comprising 2-4% of the planet mass and 16-50% of its radius. Our study is yet another demonstration that accounting for stellar activity in stars with clear rotation signals can yield more accurate planet masses, enabling a more realistic interpretation of planet interiors., Comment: Accepted to AJ 11/08/2022

Detections of molecules in the atmosphere of gas giant exoplanets allow us to investigate the physico-chemical properties of the atmospheres. Their inferred chemical composition is used as tracer of planet formation and evolution mechanisms. Currently, an increasing number of detections is showing a possible rich chemistry of the hotter gaseous planets, but whether this extends to cooler giants is still unknown. We observed four transits of WASP-80 b, a warm transiting giant planet orbiting a late-K dwarf star with the near-infrared GIANO-B spectrograph installed at the Telescopio Nazionale Galileo and performed high resolution transmission spectroscopy analysis. We report the detection of several molecular species in its atmosphere. Combining the four nights and comparing our transmission spectrum to planetary atmosphere models containing the signature of individual molecules within the cross-correlation framework, we find the presence of H2O, CH4, NH3 and HCN with high significance, tentative detection of CO2, and inconclusive results for C2H2 and CO. A qualitative interpretation of these results, using physically motivated models, suggests an atmosphere consistent with solar composition and the presence of disequilibrium chemistry and we therefore recommend the inclusion of the latter in future modelling of sub-1000K planets., Comment: 12 pages, 4 figures. AJ, Accepted July 11th, 2022

We present development progress of the scheduler for the Son Of X-Shooter (SOXS) instrument at the ESO-NTT 3.58 meter telescope. SOXS will be a single object spectroscopic facility, consisting of a two-arms high-efficiency spectrograph covering the spectral range 350-2000 nanometer with a mean resolving power R$\approx$4500. SOXS will be uniquely dedicated to the UV-visible and near infrared follow up of astrophysical transients, with a very wide pool of targets available from the streaming services of wide-field telescopes, current and future. This instrument will serve a variety of scientific scopes in the astrophysical community, with each scope eliciting its specific requirements for observation planning, that the observing scheduler has to meet. Due to directions from the European Southern Observatory (ESO), the instrument will be operated only by La Silla staff, with no astronomer present on the mountain. This implies a new challenge for the scheduling process, requiring a fully automated algorithm that should be able to present the operator not only with and ordered list of optimal targets, but also with optimal back-ups, should anything in the observing conditions change. This imposes a fast-response capability to the scheduler, without compromising the optimization process, that ensures good quality of the observations. In this paper we present the current state of the scheduler, that is now almost complete, and of its web interface., Accepted for publication in SPIE Astronomical Telescope and Instrumentation Conference proceedings - Montreal (Canada) July 2022

SOXS (SOn of X-Shooter) is a high-efficiency spectrograph with a mean Resolution-Slit product of 3500 over the entire band capable of simultaneously observing the complete spectral range 350-2000 nm. It consists of three scientific arms (the UV-VIS Spectrograph, the NIR Spectrograph and the Acquisition Camera) connected by the Common Path system to the NTT, and the Calibration Unit. We present an overview of the flow from the scientific to the technical requirements, and the realization of the sub-systems. Further, we give an overview of the methodologies used for planning and managing the assembly of the sub-systems, their integration and tests before the acceptance of the instrument in Europe (PAE) along with the plan for the integration of SOXS to the NTT. SOXS could be used as an example for the system engineering of an instrument of moderate complexity, with a large geographic spread of the team., Comment: 12 pages, 4 Figures, SPIE: Astronomical Telescope + Instrumentation, Montreal 2022. arXiv admin note: text overlap with arXiv:1812.07401

The Son-Of-XShooter (SOXS) is a single object spectrograph (UV-VIS & NIR) and acquisition camera scheduled to be mounted on the ESO 3.58-m New Technology Telescope at the La Silla Observatory. Although the underlying data reduction processes to convert raw detector data to fully-reduced science ready data are complex and multi-stepped, we have designed the SOXS Data Reduction pipeline with the core aims of providing end-users with a simple-to-use, well-documented command-line interface while also allowing the pipeline to be run in a fully automated state; streaming reduced data into the ESO Science Archive Facility without need for human intervention. To keep up with the stream of data coming from the instrument, there is the requirement to optimise the software to reduce each observation block of data well within the typical observation exposure time. The pipeline is written in Python 3 and has been built with an agile development philosophy that includes CI and adaptive planning., 10 pages, 7 figures, published in SPIE proceedings volume 12189. arXiv admin note: substantial text overlap with arXiv:2012.12678

Based on HARPS-N radial velocities (RVs) and TESS photometry, we present a full characterisation of the planetary system orbiting the late G dwarf TOI-561. After the identification of three transiting candidates by TESS, we discovered two additional external planets from RV analysis. RVs cannot confirm the outer TESS transiting candidate, which would also make the system dynamically unstable. We demonstrate that the two transits initially associated with this candidate are instead due to single transits of the two planets discovered using RVs. The four planets orbiting TOI-561 include an ultra-short period (USP) super-Earth (TOI-561 b) with period $P_{\rm b} = 0.45$ d, mass $M_{\rm b} =1.59 \pm 0.36$ M$_\oplus$ and radius $R_{\rm b}=1.42 \pm 0.07$ R$_\oplus$, and three mini-Neptunes: TOI-561 c, with $P_{\rm c} = 10.78$ d, $M_{\rm c} = 5.40 \pm 0.98$ M$_\oplus$, $R_{\rm c}= 2.88 \pm 0.09$ R$_\oplus$; TOI-561 d, with $P_{\rm d} = 25.6$ d, $M_{\rm d} = 11.9 \pm 1.3$ M$_\oplus$, $R_{\rm d} = 2.53 \pm 0.13$ R$_\oplus$; and TOI-561 e, with $P_{\rm e} = 77.2$ d, $M_{\rm e} = 16.0 \pm 2.3$ M$_\oplus$, $R_{\rm e} = 2.67 \pm 0.11$ R$_\oplus$. Having a density of $3.0 \pm 0.8$ g cm$^{-3}$, TOI-561 b is the lowest density USP planet known to date. Our N-body simulations confirm the stability of the system and predict a strong, anti-correlated, long-term transit time variation signal between planets d and e. The unusual density of the inner super-Earth and the dynamical interactions between the outer planets make TOI-561 an interesting follow-up target., 20 pages, 12 figures. Accepted for publication in MNRAS

The atmospheres of gaseous giant exoplanets orbiting close to their parent stars (hot Jupiters) have been probed for nearly two decades. They allow us to investigate the chemical and physical properties of planetary atmospheres under extreme irradiation conditions. Previous observations of hot Jupiters as they transit in front of their host stars have revealed the frequent presence of water vapour and carbon monoxide in their atmospheres; this has been studied in terms of scaled solar composition under the usual assumption of chemical equilibrium. Both molecules as well as hydrogen cyanide were found in the atmosphere of HD 209458b, a well studied hot Jupiter (with equilibrium temperature around 1,500 kelvin), whereas ammonia was tentatively detected there and subsequently refuted. Here we report observations of HD 209458b that indicate the presence of water (H2O), carbon monoxide (CO), hydrogen cyanide (HCN), methane (CH4), ammonia (NH3) and acetylene (C2H2), with statistical significance of 5.3 to 9.9 standard deviations per molecule. Atmospheric models in radiative and chemical equilibrium that account for the detected species indicate a carbon-rich chemistry with a carbon-to-oxygen ratio close to or greater than 1, higher than the solar value (0.55). According to existing models relating the atmospheric chemistry to planet formation and migration scenarios, this would suggest that HD 209458b formed far from its present location and subsequently migrated inwards. Other hot Jupiters may also show a richer chemistry than has been previously found, which would bring into question the frequently made assumption that they have solar-like and oxygen-rich compositions., Comment: As part of the Springer Nature Content Sharing Initiative, it is possible to access a view-only version of this paper by using the following SharedIt link: https://rdcu.be/cifrz

The solar telescope connected to HARPS-N has been observing the Sun since the summer of 2015. Such high-cadence, long-baseline data set is crucial for understanding spurious radial-velocity signals induced by our Sun and by the instrument. On the instrumental side, this data set allowed us to detect sub-\ms\,systematics that needed to be corrected for. The goal of this manuscript is to i) present a new data reduction software for HARPS-N, ii) demonstrate the improvement brought by this new software on the first three years of the HARPS-N solar data set, and iii) release all the obtained solar products, from extracted spectra to precise radial velocities. To correct for the instrumental systematics observed in the data reduced with the current version of the HARPS-N data reduction software (DRS version 3.7), we adapted the newly available ESPRESSO DRS (version 2.2.3) to HARPS-N and developed new optimized recipes for the spectrograph. We then compared the first three years of HARPS-N solar data reduced with the current and new DRS. The most significant improvement brought by the new DRS is a strong decrease in the day-to-day radial-velocity scatter, from 1.27 to 1.07\ms; this is thanks to a more robust method to derive wavelength solutions, but also to the use of calibrations closer in time. The newly derived solar radial-velocities are also better correlated with the chromospheric activity level of the Sun on the long-term, with a Pearson correlation coefficient of 0.93 compared to 0.77 before, which is expected from our understanding of stellar signals. Finally, we also discuss how HARPS-N spectral ghosts contaminate the measurement of the calcium activity index, and present an efficient technique to derive an index free of instrumental systematics. This paper presents a new data reduction software for HARPS-N, and demonstrates its improvements [...], Comment: 20 pages, 15 figures, 2 tables, version accepted for publication in Astronomy and Astrophysics

Funding: A.C.C. acknowledges support from the Science and Technology Facilities Council (STFC) consolidated grant No. ST/R000824/1. Radial velocity (RV) searches for Earth-mass exoplanets in the habitable zone around Sun-like stars are limited by the effects of stellar variability on the host star. In particular, suppression of convective blueshift and brightness inhomogeneities due to photospheric faculae/plage and starspots are the dominant contribution to the variability of such stellar RVs. Gaussian process (GP) regression is a powerful tool for statistically modeling these quasi-periodic variations. We investigate the limits of this technique using 800 days of RVs from the solar telescope on the High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph. These data provide a well-sampled time series of stellar RV variations. Into this data set, we inject Keplerian signals with periods between 100 and 500 days and amplitudes between 0.6 and 2.4 m s−1. We use GP regression to fit the resulting RVs and determine the statistical significance of recovered periods and amplitudes. We then generate synthetic RVs with the same covariance properties as the solar data to determine a lower bound on the observational baseline necessary to detect low-mass planets in Venus-like orbits around a Sun-like star. Our simulations show that discovering planets with a larger mass (~0.5 m s−1) using current-generation spectrographs and GP regression will require more than 12 yr of densely sampled RV observations. Furthermore, even with a perfect model of stellar variability, discovering a true exo-Venus (~0.1 m s−1) with current instruments would take over 15 yr. Therefore, next-generation spectrographs and better models of stellar variability are required for detection of such planets. Postprint

State of the art radial velocity (RV) exoplanet searches are limited by the effects of stellar magnetic activity. Magnetically active spots, plage, and network regions each have different impacts on the observed spectral lines, and therefore on the apparent stellar RV. Differentiating the relative coverage, or filling factors, of these active regions is thus necessary to differentiate between activity-driven RV signatures and Doppler shifts due to planetary orbits. In this work, we develop a technique to estimate feature-specific magnetic filling factors on stellar targets using only spectroscopic and photometric observations. We demonstrate linear and neural network implementations of our technique using observations from the solar telescope at HARPS-N, the HK Project at the Mt. Wilson Observatory, and the Total Irradiance Monitor onboard SORCE. We then compare the results of each technique to direct observations by the Solar Dynamics Observatory (SDO). Both implementations yield filling factor estimates that are highly correlated with the observed values. Modeling the solar RVs using these filling factors reproduces the expected contributions of the suppression of convective blueshift and rotational imbalance due to brightness inhomogeneities. Both implementations of this technique reduce the overall activity-driven RMS RVs from 1.64 m/s to 1.02 m/s, corresponding to a 1.28 m/s reduction in the RMS variation. The technique provides an additional 0.41 m/s reduction in the RMS variation compared to traditional activity indicators., 16 pages, 6 figures, accepted by The Astrophysical Journal

International audience; Context. The analysis of exoplanetary atmospheres by means of high-resolution spectroscopy is an expanding research field which provides information on the chemical composition, thermal structure, atmospheric dynamics, and orbital velocity of exoplanets. Aims: In this work, we aim to detect the light reflected by the exoplanet 51 Peg b by employing optical high-resolution spectroscopy. Methods: To detect the light reflected by the planetary dayside, we used optical High Accuracy Radial velocity Planet Searcher and High Accuracy Radial velocity Planet Searcher for the Northern hemisphere spectra taken near the superior conjunction of the planet, when the flux contrast between the planet and the star is maximum. To search for the weak planetary signal, we cross-correlated the observed spectra with a high signal-to-noise ratio stellar spectrum. Results: We homogeneously analyze the available datasets and derive a 10-5 upper limit on the planet-to-star flux contrast in the optical. Conclusions: The upper limit on the planet-to-star flux contrast of 10-5 translates into a low albedo of the planetary atmosphere (Ag ≲ 0.05-0.15 for an assumed planetary radius in the range of 1.5-0.9 RJup, as estimated from the planet's mass). Full Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/646/A159 Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated by the Fundación Galileo Galilei (FGG) of the Istituto Nazionale di Astrofisica (INAF) at the Observatorio del Roque de los Muchachos (La Palma, Canary Islands, Spain).

Using radial velocity measurements from four instruments, we report the mass and density of a $2.043\pm0.069 ~\rm{R}_{\oplus}$ sub-Neptune orbiting the quiet K-dwarf Wolf 503 (HIP 67285). In addition, we present improved orbital and transit parameters by analyzing previously unused short-cadence $K2$ campaign 17 photometry and conduct a joint radial velocity-transit fit to constrain the eccentricity at $0.41\pm0.05$. The addition of a transit observation by $Spitzer$ also allows us to refine the orbital ephemeris in anticipation of further follow-up. Our mass determination, $6.26^{+0.69}_{-0.70}~\rm{M}_{\odot}$, in combination with the updated radius measurements, gives Wolf 503 b a bulk density of $\rho = 2.92\pm ^{+0.50}_{-0.44}$ $\rm{g}~\rm{cm}^{-3}$. Using interior composition models, we find this density is consistent with an Earth-like core with either a substantial $\rm{H}_2\rm{O}$ mass fraction ($45^{+19.12}_{-16.15}\%$) or a modest H/He envelope ($0.5\pm0.28\%$). The low H/He mass fraction, along with the old age of Wolf 503 ($11\pm2$ Gyrs), makes this sub-Neptune an opportune subject for testing theories of XUV-driven mass loss while the brightness of its host ($J=8.3$ mag) makes it an attractive target for transmission spectroscopy., Comment: Accepted to ApJ 2021 July 15

Transiting ultra-hot Jupiters are ideal candidates to study the exoplanet atmospheres and their dynamics, particularly by means of high-resolution, high signal-to-noise ratio spectra. One such object is KELT-20b, orbiting the fast rotating A2-type star KELT-20. Many atomic species have already been found in its atmosphere, with blueshifted signals that hints at the presence of a day-to-night side wind. We aimed to observe the atmospheric Rossiter-McLaughlin effect in the ultra-hot Jupiter KELT-20b, and to study any variation of the atmospheric signal during the transit. For this purpose, we analysed five nights of HARPS-N spectra covering five transits of KELT-20b. We computed the mean line profiles of the spectra with a least-squares deconvolution, and then we extracted the stellar radial velocities by fitting them with a rotational broadening profile in order to obtain the radial velocity time-series. We used the mean line profile residuals tomography to analyse the planetary atmospheric signal and its variations. We also used the cross-correlation method to study an already known double-peak feature in the FeI planetary signal. We observed both the classical and the atmospheric Rossiter-McLaughlin effect in the radial velocity time-series. The latter gave us an estimate of the radius of the planetary atmosphere that correlates with the stellar mask used in our work: R(p+atmo)/Rp = 1.13 +/- 0.02). We isolated the planetary atmospheric trace in the tomography, and we found radial velocity variations of the planetary atmospheric signal during transit with an overall blueshift of approximatively 10 km/s, along with small variations in the signal's depth and, less significant, in the full width at half maximum (FWHM). We also find a possible variation in the structure and position of FeI signal in different transits., Comment: 13 pages, 20 figures. Accepted for publication in A&A

SOXS (Son Of X-Shooter) is a medium resolution (~4500) wide-band (0.35 - 2.0 µm) spectrograph which passed the Final Design Review in 2018. The instrument is planned to be installed at the NTT in La Silla and it is mainly composed by five different optomechanical subsystems (Common Path, NIR spectrograph, UV-VIS spectrograph, Camera, and Calibration) and other mechanical subsystems (Interface flange, Platform, cable corotator, and cooling). It is currently in the procurement and integration phase. In this paper we present the post-FDR modifications in the mechanical design due to the various iterations with the manufacturers and the actual procurement status. The last part describes the strategy used to keep under control the mechanical interfaces between the subsystems.

SOXS (Son Of X-Shooter) will be the new medium resolution (R~4500 for 1'' slit), high-efficiency, wide band spectrograph for the ESO NTT at La Silla, optimized for classification and follow-up of transient events. SOXS will simultaneously cover UV optical and NIR bands (0.35-2.00 micron) using two different arms and a pre-slit Common Path feeding system. The instrument will be also equipped by a Calibration Unit and an Acquisition Camera (AC) System. In this paper we present the final opto-mechanical design for the AC System and we describe its development status. The project is currently in manufacturing and integration phases., 8 pages, 8 figures, SPIE conference. arXiv admin note: text overlap with arXiv:1809.01526

SOXS is a new spectrograph for the New Technology Telescope (NTT), optimized for transient and variable objects, covering a wide wavelength range from 350 to 2000 nm. SOXS is equipped with a calibration unit that will be used to remove the instrument signatures and to provide wavelength calibration to the data. The calibration unit will employ seven calibration lamps: a quartz-tungsten-halogen and a deuterium lamp for the flat-field correction, a ThAr lamp and four pencil-style rare-gas lamps for the wavelength calibration. The light from the calibration lamps is injected into the spectrograph mimicking the f/11 input beam of the NTT, by using an integrating sphere and a custom doublet. The oversized illumination patch covers the length of the spectrograph slit homogeneously, with $< 1\%$ variation. The optics also supports the second mode of the unit, the star-simulator mode that emulates a point source by utilizing a pinhole mask. Switching between the direct illumination and pinhole modes is performed by a linear stage. A safety interlock switches off the main power when the lamp box cover is removed, preventing accidental UV exposure to the service personnel. All power supplies and control modules are located in an electronic rack at a distance from the telescope platform. In this presentation we describe the optical, mechanical, and electrical designs of the SOXS calibration unit, and report the status of development in which the unit is currently in the test and verification stage., 7 pages, 7 figures

PLATO is an M-class mission (M3) of the European Space Agency (ESA) whose launch is scheduled in 2026. The main aim of the mission is the detection and characterization of terrestrial exoplanets orbiting around bright solar-type star. The payload consists of 26 small telescopes: 24 "normal" cameras and 2 "fast" cameras. The huge amount of data produced by the PLATO telescopes is acquired and processed on-board by the Data Processing System (DPS) made up by various processing electronic units. The DPS of the PLATO instrument comprises the Normal and Fast DPUs (Data Processing Units) and a single ICU (Instrument Control Unit), are data routed through a SpaceWire network. The topic of this paper is the description of the architecture of the ICU and its role within the DPS, the status of the Avionic Validation Model (AVM) testing at the end of the Unit Preliminary Design Review (UPDR) performed by ESA and the results of the test of the first engineering model.

We present here the development status of the NIR spectrograph of the Son Of X-Shooter (SOXS) instrument, for the ESO/NTT telescope at La Silla (Chile). SOXS is a R~4,500 mean resolution spectrograph, with a simultaneously coverage from about 0.35 to 2.00 μm. It will be mounted at the Nasmyth focus of the NTT. The two UV-VIS-NIR wavelength ranges will be covered by two separated arms. The NIR spectrograph is a fully cryogenic echelle-dispersed spectrograph, working in the range 0.80-2.00 μm, equipped with a Hawaii H2RG IR array from Teledyne. The whole spectrograph will be cooled down to about 150 K (but the array at 40 K), to lower the thermal background, and equipped with a thermal filter to block any thermal radiation above 2.0 μm. In this work, we will show the advanced phase of integration of the NIR spectrograph.

PLATO is ESA's upcoming exoplanet-hunting mission. The spacecraft has 26 cameras equipped with a total of 104 individual CCDs, which together provide more than 2,000 megapixels, giving a combined optical sensitivity surface of 0.66m2. This is more than twice as much detector area than on ESA's Gaia mission, the largest camera ever flown in space. To measure changes in stellar brightness, the CCDs are read out at a cadence of 25 seconds, resulting in a massive amount of data that has to be processed on-board. In a pre-reduction step, hundreds of thousands of small windows of the target stars, called imagettes, are extracted from the detector arrays. This reduction process decreases the data volume down from several gigabytes to 25 MiB per acquisition period. Following this step, the remaining science data are sent to the instrument control unit (ICU), where they are processed and compressed in a lossless manner. While some science data products, such as measured backgrounds and fluxes, can be processed in software, the number of imagettes to be compressed (90% of the total science data) exceeds the available CPU resources. To solve this critical problem, a specialised hardware data compressor logic was developed for an RTAX-2000 field-programmable gate array (FPGA). The implemented compression method decorrelates the data temporally by a running average, which has an exponential tail. This pre-encoding step results in an almost geometric distribution of the residuals, a suitable input for the successive Golomb encoder. The set of parameters that control the encoder are semi- adaptive, i.e., they self-adjust to the data at certain intervals. While in principle being quite straightforward, the implementation turned out to be very challenging with the required handling of the data streams in real-time. With our approach we are able to meet the high requirements and managed to process the imagette data lossless with a speed of 2 MBps at a compression ratio up to 3.2. This paper shows how the PLATO data compression concept works, which algorithms are involved in it, and discusses the specifics of the hardware and software implementation.

SOXS (Son Of X-Shooter) is a single object spectrograph, characterized by offering a wide simultaneous spectral coverage from U- to H-band, built by an international consortium for the 3.6-m ESO New Technology Telescope at the La Silla Observatory, in the Southern part of the Chilean Atacama Desert. The consortium is focussed on a clear scientific goal: the spectrograph will observe all kind of transient and variable sources discovered by different surveys with a highly flexible schedule, updated daily, based on the Target of Opportunity concept. It will provide a key spectroscopic partner to any kind of imaging survey, becoming one of the premier transient follow-up instruments in the Southern hemisphere. SOXS will study a mixture of transients encompassing all distance scales and branches of astronomy, including fast alerts (such as gamma-ray bursts and gravitational waves), mid-term alerts (such as supernovae and X-ray transients), and fixed-time events (such as the close-by passage of a minor planet or exoplanets). It will also have the scope to observe active galactic nuclei and blazars, tidal disruption events, fast radio bursts, and more. Besides of the consortium programs on guaranteed time, the instrument is offered to the ESO community for any kind of astrophysical target. The project has passed the Final Design Review and is currently in manufacturing and integration phase. This paper describes the development status of the project., Proc SPIE Volume 11447, Ground-based and Airborne Instrumentation for Astronomy VIII, 1144709,2020

SOXS (Son Of X-Shooter) is a forthcoming instrument for ESO-NTT, mainly dedicated to the spectroscopic study of transient events and is currently starting the AIT (Assembly, Integration, and Test) phase. It foresees a visible spectrograph, a near-Infrared (NIR) spectrograph, and an acquisition camera for light imaging and secondary guiding. The optimal setup and the monitoring of SOXS are carried out with a set of software-controlled motorized components and sensors. The instrument control software (INS) also manages the observation and calibration procedures, as well as maintenance and self-test operations. The architecture of INS, based on the latest release of the VLT Software (VLT2019), has been frozen; the code development is in an advanced state for what concerns supported components and observation procedures, which run in simulation. In this proceeding we present the INS current status, focusing in particular on the ongoing efforts in the support of two non-standard, "special" devices. The first special device is the piezoelectric slit exchanger for the NIR spectrograph; the second special device is the piezoelectric tip-tilt corrector used for active compensation of mechanical flexures of the instrument., 8 pages, 4 figures

Context. Young stars and multi-planet systems are two types of primary objects that allow us to study, understand, and constrain planetary formation and evolution theories. Aims. We validate the physical nature of two Neptune-sized planets transiting TOI-942 (TYC 5909-319-1), a previously unacknowledged young star (50−20+30 Myr) observed by the TESS space mission in Sector 5. Methods. Thanks to a comprehensive stellar characterization, TESS light curve modeling and precise radial-velocity measurements, we validated the planetary nature of the TESS candidate and detected an additional transiting planet in the system on a larger orbit. Results. From photometric and spectroscopic observations we performed an exhaustive stellar characterization and derived the main stellar parameters. TOI-942 is a relatively active K2.5V star (log R′HK = −4.17 ± 0.01) with rotation period Prot = 3.39 ± 0.01 days, a projected rotation velocity v sin i⋆ = 13.8 ± 0.5 km s−1, and a radius of ~0.9 R⊙. We found that the inner planet, TOI-942 b, has an orbital period Pb = 4.3263 ± 0.0011 days, a radius Rb = 4.242−0.313+0.376 R⊕, and a mass upper limit of 16 M⊕ at 1σ confidence level. The outer planet, TOI-942 c, has an orbital period Pc = 10.1605−0.0053+0.0056 days, a radius Rc = 4.793−0.351+0.410 R⊕, and a mass upper limit of 37 M⊕ at 1σ confidence level.

Stellar magnetic activity produces time-varying distortions in the photospheric line profiles of solar-type stars. These lead to systematic errors in high-precision radial-velocity measurements, which limit efforts to discover and measure the masses of low-mass exoplanets with orbital periods of more than a few tens of days. We present a new data-driven method for separating Doppler shifts of dynamical origin from apparent velocity variations arising from variability-induced changes in the stellar spectrum. We show that the autocorrelation function (ACF) of the cross-correlation function used to measure radial velocities is effectively invariant to translation. By projecting the radial velocities on to a subspace labelled by the observation identifiers and spanned by the amplitude coefficients of the ACF's principal components, we can isolate and subtract velocity perturbations caused by stellar magnetic activity. We test the method on a 5-year time sequence of 853 daily 15-minute observations of the solar spectrum from the HARPS-N instrument and solar-telescope feed on the 3.58-m Telescopio Nazionale Galileo. After removal of the activity signals, the heliocentric solar velocity residuals are found to be Gaussian and nearly uncorrelated. We inject synthetic low-mass planet signals with amplitude $K=40$ cm s$^{-1}$ into the solar observations at a wide range of orbital periods. Projection into the orthogonal complement of the ACF subspace isolates these signals effectively from solar activity signals. Their semi-amplitudes are recovered with a precision of $\sim~6.6$ cm s$^{-1}$, opening the door to Doppler detection and characterization of terrestrial-mass planets around well-observed, bright main-sequence stars across a wide range of orbital periods., 19 pages, 15 figures, accepted 2 May 2021 for publication in MNRAS

We present the confirmation of two new planets transiting the nearby mid-M dwarf LTT 3780 (TIC 36724087, TOI-732, $V=13.07$, $K_s=8.204$, $R_s$=0.374 R$_{\odot}$, $M_s$=0.401 M$_{\odot}$, d=22 pc). The two planet candidates are identified in a single TESS sector and are validated with reconnaissance spectroscopy, ground-based photometric follow-up, and high-resolution imaging. With measured orbital periods of $P_b=0.77$ days, $P_c=12.25$ days and sizes $r_{p,b}=1.33\pm 0.07$ R$_{\oplus}$, $r_{p,c}=2.30\pm 0.16$ R$_{\oplus}$, the two planets span the radius valley in period-radius space around low mass stars thus making the system a laboratory to test competing theories of the emergence of the radius valley in that stellar mass regime. By combining 63 precise radial-velocity measurements from HARPS and HARPS-N, we measure planet masses of $m_{p,b}=2.62^{+0.48}_{-0.46}$ M$_{\oplus}$ and $m_{p,c}=8.6^{+1.6}_{-1.3}$ M$_{\oplus}$, which indicates that LTT 3780b has a bulk composition consistent with being Earth-like, while LTT 3780c likely hosts an extended H/He envelope. We show that the recovered planetary masses are consistent with predictions from both photoevaporation and from core-powered mass loss models. The brightness and small size of LTT 3780, along with the measured planetary parameters, render LTT 3780b and c as accessible targets for atmospheric characterization of planets within the same planetary system and spanning the radius valley., Comment: Accepted to AJ. 8 figures, 6 tables. CSV file of the RV measurements (i.e. Table 2) are included in the source code

Ultra-short period (USP) planets are a class of exoplanets with periods shorter than one day. The origin of this sub-population of planets is still unclear, with different formation scenarios highly dependent on the composition of the USP planets. A better understanding of this class of exoplanets will, therefore, require an increase in the sample of such planets that have accurate and precise masses and radii, which also includes estimates of the level of irradiation and information about possible companions. Here we report a detailed characterization of a USP planet around the solar-type star HD 80653 $\equiv$ EP 251279430 using the K2 light curve and 108 precise radial velocities obtained with the HARPS-N spectrograph, installed on the Telescopio Nazionale Galileo. From the K2 C16 data, we found one super-Earth planet ($R_{b}=1.613\pm0.071 R_{\oplus}$) transiting the star on a short-period orbit ($P_{\rm b}=0.719573\pm0.000021$ d). From our radial velocity measurements, we constrained the mass of HD 80653 b to $M_{b}=5.60\pm0.43 M_{\oplus}$. We also detected a clear long-term trend in the radial velocity data. We derived the fundamental stellar parameters and determined a radius of $R_{\star}=1.22\pm0.01 R_{\odot}$ and mass of $M_{\star}=1.18\pm0.04 M_{\odot}$, suggesting that HD 80653, has an age of $2.7\pm1.2$ Gyr. The bulk density ($\rho_{b} = 7.4 \pm 1.1$ g cm$^{-3}$) of the planet is consistent with an Earth-like composition of rock and iron with no thick atmosphere. Our analysis of the K2 photometry also suggests hints of a shallow secondary eclipse with a depth of 8.1$\pm$3.7 ppm. Flux variations along the orbital phase are consistent with zero. The most important contribution might come from the day-side thermal emission from the surface of the planet at $T\sim3480$ K., Comment: 15 pages, 12 figures; accepted by A&A