H2O Emission Research Articles

Contemporaneous high-angular-resolution imaging of the AGB star W Hya in vibrationally excited H2O lines and visible polarized light with ALMA and VLT/SPHERE-ZIMPOL

Aims. We present contemporaneous high-angular-resolution millimeter imaging and visible polarimetric imaging of the nearby asymptotic giant branch (AGB) star W Hya to better understand the dynamics and dust formation within a few stellar radii. Methods. The star W Hya was observed in two vibrationally excited H2O lines at 268 and 251 GHz with Atacama Large Millimeter/submillimeter Array (ALMA) at a spatial resolution of 16 × 20 mas and at 748 and 820 nm at a resolution of 26 × 27 mas with the Very Large Telescope (VLT)/Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE)-Zurich Imaging Polarimeter (ZIMPOL). Results. ALMA’s high spatial resolution allowed us to image strong emission of the vibrationally excited H2O line at 268 GHz (v2 = 2, JKa, Kc = 65, 2–74, 3) over the stellar surface instead of absorption against the continuum, which is expected for thermal excitation. Strong, spotty emission was also detected along and just outside the stellar disk limb at an angular distance of ∼40 mas (∼1.9 R⋆), extending to ∼60 mas (∼2.9 R⋆). Another H2O line (v2 = 2, JKa, Kc = 92, 8–83, 5) at 251 GHz with a similar upper-level energy was tentatively identified, which shows absorption over the stellar surface. This suggests that the emission over the surface seen in the 268 GHz H2O line is suprathermal or even maser emission. The estimated gas temperature and H2O density are consistent with the radiatively pumped masers. The 268 GHz H2O line reveals global infall at up to ∼15 km s−1 within 2–3 R⋆, but outflows at up to ∼8 km s−1 are also present. The polarized intensity maps obtained in the visible reveal clumpy dust clouds forming within ∼40 mas (∼1.9 R⋆) with a particularly prominent cloud in the SW quadrant and a weaker cloud in the east. The 268 GHz H2O emission overlaps very well with the visible polarized intensity maps, which suggests that both the nonthermal and likely maser H2O emission and the dust originate from dense, cool pockets in the inhomogeneous atmosphere within ∼2–3 R⋆.

Accretion and Outflow in Orion-KL Source I

We present Atacama Large Millimeter/submillimeter Array observations of SiO, SiS, H2O, NaCl, and SO line emission at ∼30–50 mas resolution. These images map the molecular outflow and disk of Orion Source I (SrcI) on ∼12–20 au scales. Our observations show that the flow of material around SrcI creates a turbulent boundary layer in the outflow from SrcI, which may dissipate angular momentum in the rotating molecular outflow into the surrounding medium. Additionally, the data suggest that the proper motion of SrcI may have a significant effect on the structure and evolution of SrcI and its molecular outflow. As the motion of SrcI funnels material between the disk and the outflow, some material may be entrained into the outflow and accrete onto the disk, creating shocks that excite the NaCl close to the disk surface.

MINDS

Context. The majority of young stars form in multiple systems, the properties of which can significantly impact the evolution of any circumstellar disks. Aims. We investigate the physical and chemical properties of the equal-mass, small-separation (~66 milliarcsecond, ~9 au) binary system DF Tau. Previous spatially resolved observations indicate that only DF Tau A has a circumstellar disk, while DF Tau B does not, as concluded by a lack of accretion signatures and a near-infrared excess. Methods. We present JWST-MIRI MRS observations of DF Tau. The MIRI spectrum shows emission from a forest of H2O lines and emission from CO, C2H2, HCN, CO2, and OH. Local thermodynamic equilibrium slab models were used to determine the properties of the gas. The binary system is not spatially or spectrally resolved in the MIRI observations; therefore, we analyzed high spatial and spectral resolution observations from ALMA, VLTI-GRAVITY, and IRTF-iSHELL to aid in the interpretation of the molecular emission observed with JWST. Results. The 1.3 mm ALMA observations show two equal-brightness sources of compact (R ≲ 3 au) continuum emission that are detected at high significance, with separations consistent with astrometry from VLTI-GRAVITY and movement consistent with the known orbital parameters of the system. We interpret this as a robust detection of the disk around DF Tau B, which we suggest may host a small (~1 au) cavity; such a cavity would reconcile all of the observations of this source. In contrast, the disk around DF Tau A is expected to be a full disk, and spatially and spectrally resolved dust and gas emission traced by ground-based infrared observations point to hot, close-in (≲0.2 au) material around this star. High-temperature emission (~500–1000 K) from H2O, HCN, and potentially C2H2 in the MIRI data likely originates in the disk around DF Tau A, while a cold H2O component (≲200 K) with an extended emitting area is consistent with an origin from both disks. Conclusions. Given the unique characteristics of this binary pair, complementary observations are critical for constraining the properties of these disks. Despite the very compact outer disk properties, the inner disk composition and the conditions of the DF Tau disks are remarkably similar to those of isolated systems, suggesting that neither the outer disk evolution nor the close binary nature are driving factors in setting the inner disk chemistry in this system. However, constraining the geometry of the disk around DF Tau B, via higher angular resolution ALMA observations for instance, would provide additional insight into the properties of the mid-infrared gas emission observed with MIRI. JWST observations of spatially resolved binaries, at a range of separations, will be important for understanding the impact of binarity on inner disk chemistry more generally.

Evidence for Nightside Water Emission Found in Transit of Ultra-hot Jupiter WASP-33 b

To date, the dayside thermal structure of ultra-hot Jupiters (UHJs) is generally considered to be inverted, but their nightside thermal structure has been less explored. Here, we explore the impact of nightside thermal emission on high-resolution infrared transmission spectroscopy, which should not be neglected, especially for UHJs. We present a general equation for the high-resolution transmission spectrum that includes planetary nightside thermal emission. This provides a new way to infer the thermal structure of the planetary nightside with high-resolution transmission spectroscopy. Using the cross-correlation technique, we find evidence for the presence of an H2O emission signature on the UHJ WASP-33 b during the transit, indicating an inverted temperature structure on its nightside. Such a result suggests a stronger heat transport through the circulation than currently expected. An alternative explanation is that the rotating visible hemisphere during transit leads to the potential contribution of the limb and dayside atmospheres to the detected emission signature. In the future, the combination of high-resolution, full-phase-curve spectroscopic observations and general circulation models will hopefully solve this puzzle and provide a complete picture of the three-dimensional nature of the chemistry, circulation, and thermal structure of UHJs.

An investigation on the H2O, unburned H2 and NO emission characteristics from a direct injection hydrogen engine

Hydrogen engines show great potential as a power source with good combustion performance, zero carbon emissions, and diverse sources. However, the exhaust emission characteristics with high water vapor (H2O) content have not yet been clarified. This study presents the exhaust emissions of a heavy-duty direct-injection hydrogen engine under various operational parameters, with a focus on the H2O content. The results reveal important exhaust emissions characteristics of the hydrogen engine, including lower exhaust temperature (200 °C–400 °C), higher unburned H2 emissions (up to 17100 ppm), less nitrogen oxide (NO) generation (<1000 ppm), and higher H2O content (6%–40%). Additionally, unburned H2 rises, and NO and H2O decrease as the excess air ratio (λ) increases. When λ is greater than 3, NO levels fall sharply to below 100 ppm. Optimal emissions performance is achieved with a 5 °CA BTDC ignition timing where low levels of H2, H2O, and NO are maintained. Increasing hydrogen injection pressure decreases H2 but raises exhaust temperature, H2O, and NO emissions. Excessively delaying hydrogen injection timing adversely affects the concentration gradient in the cylinder, increasing unburned H2 emissions. The best emissions performance is observed at a hydrogen injection timing of 110 °CA BTDC.

The impact of struvite presence on the thermal decomposition of sewage sludge, including formation of NOx emissions

Monoincineration of sewage sludge (SS) is becoming a prevailing type of SS treatment due to its contamination and the ability to achieve enriched concentration of valuable inorganics in the end ash. In order to improve the recovery potential, particularly of inorganic, phosphorous (P) bearing species, thermal transformations of organic as well as inorganic SS compounds have to be considered. While important gains in predictive capability have already been made through extensive description of organic part decomposition, P is mostly present in the inorganic part of SS, together with notable amount of nitrogen (N). Current models consider these species in a simplified manner, making the ability to predict P and N fate during thermal treatment limited. The present work focuses on development and implementation of a one step reaction kinetics mechanism for struvite, a common P and N bearing compound in SS, which also presents an important route for P and N recovery. The new mechanism is implemented into an existing SS organic fraction decomposition mechanism and validated using 0D multiphase reactor simulations in Chemkin software. Results reveal up to 10 s faster temperature increase and decomposition of SS with the presence of struvite due to emission of NH3 and H2O occurring already from 350 °C onwards. The NH3 emissions are especially important as they lead to higher NOx formation. The work presents large potential for improving thermal decomposition prediction as well as emission mitigation strategies if struvite is included in the thermal decomposition models of SS. The developed methodology allows efficient implementation of also other P and N bearing species in the inorganic part of kinetic mechanism.

Water vapour masers in long-period variable stars

Context. Water maser emission is often found in the circumstellar envelopes of evolved stars, that is, asymptotic giant branch stars and red supergiants with oxygen-rich chemistry. The H2O emission shows strong variability in evolved stars of both of these types. Aims. We wish to understand the reasons for the strong variability of water masers emitted at 22 GHz. In this paper, we study U Her and RR Aql as representatives of Mira variable stars. Methods. We monitored U Her and RR Aql in the 22 GHz maser line of water vapour with single-dish telescopes. The monitoring period covered about two decades between 1990 and 2011, with a gap between 1997 and 2000 in the case of RR Aql. Observations were also made in 1987 and 2015 before and after the period of contiguous monitoring. In addition, maps of U Her were obtained in the period 1990–1992 with the Very Large Array. Results. We find that the strongest emission in U Her is located in a shell with boundaries of 11–25 AU. The gas-crossing time is 8.5 yr. We derive lifetimes for individual maser clouds of ≤4 yr based on the absence of detectable line-of-sight velocity drifts of the maser emission. The shell is not evenly filled, and its structure is maintained over much longer timescales than those of individual maser clouds. Both stars show brightness variability on several timescales. The prevalent variation is periodic, following the optical variability of the stars with a lag of 2–3 months. Superposed are irregular fluctuations of a few months in duration, with increased or decreased excitation at particular locations, and long-term systematic variations on timescales of a decade or more. Conclusions. The properties of the maser emission are governed by those of the stellar wind while traversing the H2O maser shell. Inhomogeneities in the wind affecting the excitation conditions and prevalent beaming directions likely cause the variations seen on timescales of longer than the stellar pulsation period. We propose the existence of long-living regions in the shells, which maintain favourable excitation conditions on timescales of the wind-crossing times through the shells or orbital periods of (sub)stellar companions. The H2O maser properties in these two Mira variables are remarkably similar to those in the semiregular variables studied in our previous papers regarding shell location, outflow velocity, and lifetime. The only difference is the regular brightness variations of the Mira variables caused by the periodic pulsation of the stars.

Studies on the Thermal Decomposition Course of Nitrogen-Rich Heterocyclic Esters as Potential Drug Candidates and Evaluation of Their Thermal Stability and Properties.

Drug candidates must undergo thermal evaluation as early as possible in the preclinical phase of drug development because undesirable changes in their structure and physicochemical properties may result in decreased pharmacological activity or enhanced toxicity. Hence, the detailed evaluation of nitrogen-rich heterocyclic esters as potential drug candidates, i.e., imidazolidinoannelated triazinylformic acid ethyl esters 1-3 (where R1 = 4-CH3 or 4-OCH3 or 4-Cl, and R2 = -COOC2H5) and imidazolidinoannelated triazinylacetic acid methyl esters 4-6 (where R1 = 4-CH3 or 4-OCH3 or 4-Cl, and R2 = -CH2COOCH3)-in terms of their melting points, melting enthalpy values, thermal stabilities, pyrolysis, and oxidative decomposition course-has been carried out, using the simultaneous thermal analysis methods (TG/DTG/DSC) coupled with spectroscopic techniques (FTIR and QMS). It was found that the melting process (documented as one sharp peak related to the solid-liquid phase transition) of the investigated esters proceeded without their thermal decomposition. It was confirmed that the melting points of the tested compounds increased in relation to R1 and R2 as follows: 2 (R1 = 4-OCH3; R2 = -COOC2H5) < 6 (R1 = 4-Cl; R2 = -CH2COOCH3) < 5 (R1 = 4-OCH3; R2 = -CH2COOCH3) < 3 (R1 = 4-Cl; R2 = -COOC2H5) < 1 (R1 = 4-CH3; R2 = -COOC2H5) < 4 (R1 = 4-CH3; R2 = -CH2COOCH3). All polynitrogenated heterocyclic esters proved to be thermally stable up to 250 °C in inert and oxidising conditions, although 1-3 were characterised by higher thermal stability compared to 4-6. The results confirmed that both the pyrolysis and the oxidative decomposition of heterocyclic ethyl formates/methyl acetates with para-substitutions at the phenyl moiety proceed according to the radical mechanism. In inert conditions, the pyrolysis process of the studied molecules occurred with the homolytic breaking of the C-C, C-N, and C-O bonds. This led to the emission of alcohol (ethanol in the case of 1-3 or methanol in the case of 4-6), NH3, HCN, HNCO, aldehydes, CO2, CH4, HCl, aromatics, and H2O. In turn, in the presence of air, cleavage of the C-C, C-N, and C-O bonds connected with some oxidation and combustion processes took place. This led to the emission of the corresponding alcohol depending on the analysed class of heterocyclic esters, NH3, HCN, HNCO, aldehydes, N2, NO/NO2, CO, CO2, HCl, aromatics, and H2O. Additionally, after some biological tests, it was proven that all nitrogen-rich heterocyclic esters-as potential drug candidates-are safe for erythrocytes, and some of them are able to protect red blood cells from oxidative stress-induced damage.

Probing the interstellar medium of the quasar BRI 0952−0115

Context. The extent of the effect of active galactic nuclei (AGN) on their host galaxies at high-redshift is not apparent. The processes governing the co-eval evolution of the stellar mass and the mass of the central supermassive black hole, along with the effects of the supermassive black hole on the host galaxy, remain unclear. Studying this effect in the distant universe is a difficult process as the mechanisms of tracing AGN activity can often be inaccurately associated with intense star formation and vice versa. Aims. Our aim is to better understand the processes governing the interstellar medium (ISM) of the quasar BRI 0952−0952 at z = 4.432, specifically with regard to the individual heating processes at work and to place the quasar in an evolutionary context. Methods. We analyzed ALMA archival bands 3, 4, and 6 data and combined the results with high-resolution band-7 ALMA observations of the quasar. We detected [C I](2–1), [C II](2P3/2 − 2P1/2), CO(5–4), CO(7–6), CO(12–11), OH 2Π1/2(3/2 − 1/2), and H2O(211 − 202), and we report a tentative detection of OH+. We updated the lensing model and we used the radiative transfer code MOLPOP-CEP to produce line emission models which we compared with our observations. Results. We used the [C I] line emission to estimate the total molecular gas mass in the quasar. We present results from the radiative transfer code MOLPOP-CEP constraining the properties of the CO emission and suggest different possible scenarios for heating mechanisms within the quasar. We extended our results from MOLPOP-CEP to the additional line species detected in the quasar to place stronger constraints on the ISM properties. Conclusions. Modeling from the CO SLED suggests that there are extreme heating mechanisms operating within the quasar in the form of star formation or AGN activity; however, with the current data, it remains unclear which of the two is the preferred mechanism as both models reasonably reproduce the observed CO line fluxes. The updated lensing model suggests a velocity gradient across the [C II] line, suggestive of ongoing kinematical processes within the quasar. We find that the H2O emission in BRI 0952 is likely correlated with star-forming regions of the ISM. We used the molecular gas mass from [C I] to calculate a depletion time for the quasar. We conclude that BRI 0952−0952 is a quasar with a significant AGN contribution while also showing signs of extreme starburst activity, indicating that the quasar could be in a transitional phase between a starburst-dominated stage and an AGN-dominated stage.

JWST MIRI MRS Images of Disk Winds, Water, and CO in an Edge-on Protoplanetary Disk

We present JWST MIRI MRS observations of the edge-on protoplanetary disk around the young subsolar-mass star Tau 042021, acquired as part of the Cycle 1 GO program “Mapping Inclined Disk Astrochemical Signatures.” These data resolve the mid-IR spatial distributions of H2, revealing X-shaped emission extending to ∼200 au above the disk midplane with a semiopening angle of 35° ± 5°. We do not velocity-resolve the gas in the spectral images, but the measured semiopening angle of the H2 is consistent with a magnetohydrodynamic wind origin. A collimated, bipolar jet is seen in forbidden emission lines from [Ne ii], [Ne iii], [Ni ii], [Fe ii], [Ar ii], and [S iii]. Extended H2O and CO emission lines are also detected, reaching diameters of ∼90 and 190 au, respectively. Hot molecular emission is not expected at such radii, and we interpret its extended spatial distribution as scattering of inner disk molecular emission by dust grains in the outer disk surface. H i recombination lines, characteristic of inner disk accretion shocks, are similarly extended and are likely also scattered light from the innermost star–disk interface. Finally, we detect extended polycyclic aromatic hydrocarbon (PAH) emission at 11.3 μm cospatial with the scattered-light continuum, making this the first low-mass T Tauri star around which extended PAHs have been confirmed, to our knowledge. MIRI MRS line images of edge-on disks provide an unprecedented window into the outflow, accretion, and scattering processes within protoplanetary disks, allowing us to constrain the disk lifetimes and accretion and mass-loss mechanisms.

Sub-parsec-scale jet-driven water maser with possible gravitational acceleration in the radio galaxy NGC 1052

Abstract We report sub-parsec-scale observations of the 321 GHz H2O emission line in the radio galaxy NGC 1052. The H2O line emitter size is constrained in &amp;lt;0.6 mas distributed on the continuum core component. The brightness temperature exceeding 106 K and the intensity variation indicate certain evidence for maser emission. The maser spectrum consists of redshifted and blueshifted velocity components spanning ∼400 km s−1, separated by a local minimum around the systemic velocity of the galaxy. The spatial distribution of maser components shows a velocity gradient along the jet direction, implying that the population-inverted gas is driven by the jets interacting with the molecular torus. We identified a significant change of the maser spectra between two sessions separated by 14 days. The maser profile showed a radial velocity drift of 127 ± 13 km s−1 yr−1 implying inward gravitational acceleration at 5000 Schwarzschild radii. The results demonstrate the feasibility of future very long baseline interferometry observations to resolve the jet–torus interacting region.

MINDS. JWST/MIRI Reveals a Dynamic Gas-rich Inner Disk inside the Cavity of SY Cha

SY Cha is a T Tauri star surrounded by a protoplanetary disk with a large cavity seen in the millimeter continuum but has the spectral energy distribution of a full disk. Here we report the first results from JWST/Mid-InfraRed Instrument (MIRI) Medium Resolution Spectrometer (MRS) observations taken as part of the MIRI mid-INfrared Disk Survey (MINDS) GTO Program. The much improved resolution and sensitivity of MIRI-MRS compared to Spitzer enables a robust analysis of the previously detected H2O, CO, HCN, and CO2 emission as well as a marginal detection of C2H2. We also report the first robust detection of mid-infrared OH and rovibrational CO emission in this source. The derived molecular column densities reveal the inner disk of SY Cha to be rich in both oxygen- and carbon-bearing molecules. This is in contrast to PDS 70, another protoplanetary disk with a large cavity observed with JWST, which displays much weaker line emission. In the SY Cha disk, the continuum, and potentially the line, flux varies substantially between the new JWST observations and archival Spitzer observations, indicative of a highly dynamic inner disk.

Diverse Molecular Gas Excitations in Quasar Host Galaxies at z ∼ 6

We present observations using the Northern Extended Millimetre Array (NOEMA) of CO and H2O emission lines and the underlying dust continuum in two quasars at z ∼ 6, i.e., P215−16 at z = 5.78 and J1429+5447 at z = 6.18. Notably, among all published CO spectral line energy distributions (SLEDs) of quasars at z ∼ 6, the two systems reveal the highest and the lowest CO levels of excitation, respectively. Our radiative transfer modeling of the CO SLED of P215−16 suggests that the molecular gas heated by active galactic nuclei could be a plausible origin for the high CO excitation. For J1429+5447, we obtain the first well-sampled CO SLED (from transitions from 2−1 to 10−9) of a radio-loud quasar at z ≳ 6. Analysis of the CO SLED suggests that a component from a single photodissociation region could explain the CO excitation in the radio-loud quasar J1429+5447. This work highlights the utility of the CO SLED in uncovering the properties of the interstellar medium in these young quasar–starburst systems at the highest redshift. The diversity of the CO SLEDs reveals the complexities in gas conditions and excitation mechanisms at their early evolutionary stage.

Application of Simultaneous and Coupled Thermal Analysis Techniques in Studies on the Melting Process, Course of Pyrolysis and Oxidative Decomposition of Fused Triazinylacetohydrazides.

The effect of the structure of promising antioxidant agents with prospective medical use, i.e., unsubstituted and para-substituted annelated triazinylacetic acid hydrazides, on their melting points, thermal stabilities, pyrolysis and oxidative decomposition stages and the type of volatiles emitted under heating with the use of DSC and TG/DTG/FTIR/QMS methods was evaluated and discussed. The melting point of the investigated compounds increased with an enhanced number of electrons (directly correlated with their molecular weight). Melting enthalpy values were determined and presented for all the studied compounds. The pyrolysis and oxidative decomposition processes of the analysed molecules consisted of several poorly separated stages, which indicated a multi-step course of the decomposition reactions. It was found that the thermal stability of the tested compounds depended on the type of substituent at the para position of the phenyl moiety or its absence. In both atmospheres used (air and helium), the thermal stability increased in relation to R as follows: -CH3 ≤ -OCH3 < -H < -OC2H5. In an inert atmosphere, it was higher by approx. 8-18 °C than in an oxidative atmosphere. The pyrolysis was connected with the emission of NH3, HCN, HNCO, HCONH2, HCHO, CO2, CO and H2O in the case of all the tested compounds, regardless of the substituent attached. In the case of the derivative containing the para-CH3 group, para-toluidine was an additional emitted aromatic product. In turn, emissions of aniline and alcohol (methanol or ethanol) for compounds with the para-OCH3 and para-OC2H5 groups, respectively, were confirmed. In oxidative conditions, the release of NH3, NO, HCN, HNCO, HCONH2, CO2, H2O and cyanogen (for all the compounds) and para-toluidine (for the para-CH3 derivative), aniline (for para-OCH3, para-OC2H5 and unsubstituted derivatives) and acetaldehyde (for the para-OC2H5 derivative) were clearly observed. No alcohol emissions were recorded for either compound containing the para-OCH3- or para-OC2H5-substitututed phenyl ring. These results confirmed that the pyrolysis and oxidative decomposition of the investigated annelated triazinylacetohydrazides occurred according to the radical mechanism. Moreover, in the presence of oxygen, the reactions of volatiles and residues with oxygen (oxidation) and the combustion process additionally proceeded.

MINDS

Context. The Mid-InfraRed Instrument (MIRI) Medium Resolution Spectrometer (MRS) on board the James Webb Space Telescope (JWST) allows us to probe the inner regions of protoplanetary disks, where the elevated temperatures result in an active chemistry and where the gas composition may dictate the composition of planets forming in this region. The disk around the classical T Tauri star Sz 98, which has an unusually large dust disk in the millimetre with a compact core, was observed with the MRS, and we examine its spectrum here. Aims. We aim to explain the observations and put the disk of Sz 98 in context with other disks, with a focus on the H2O emission through both its ro-vibrational and pure rotational emission. Furthermore, we compare our chemical findings with those obtained for the outer disk from Atacama Large Millimeter/submillimeter Array (ALMA) observations. Methods. In order to model the molecular features in the spectrum, the continuum was subtracted and local thermodynamic equilibrium (LTE) slab models were fitted. The spectrum was divided into different wavelength regions corresponding to H2O lines of different excitation conditions, and the slab model fits were performed individually per region. Results. We confidently detect CO, H2O, OH, CO2, and HCN in the emitting layers. Despite the plethora of H2O lines, the isotopo-logue H218O is not detected. Additionally, no other organics, including C2H2, are detected. This indicates that the C/O ratio could be substantially below unity, in contrast with the outer disk. The H2O emission traces a large radial disk surface region, as evidenced by the gradually changing excitation temperatures and emitting radii. Additionally, the OH and CO2 emission is relatively weak. It is likely that H2O is not significantly photodissociated, either due to self-shielding against the stellar irradiation, or UV shielding from small dust particles. While H2O is prominent and OH is relatively weak, the line fluxes in the inner disk of Sz 98 are not outliers compared to other disks. Conclusions. The relative emitting strength of the different identified molecular features points towards UV shielding of H2O in the inner disk of Sz 98, with a thin layer of OH on top. The majority of the organic molecules are either hidden below the dust continuum, or not present. In general, the inferred composition points to a sub-solar C/O ratio (&lt;0.5) in the inner disk, in contrast with the larger than unity C/O ratio in the gas in the outer disk found with ALMA.

Z-GAL: A NOEMA spectroscopic redshift survey of brightHerschelgalaxies

Using the IRAM NOrthern Extended Millimetre Array (NOEMA), we conducted a Large Programme (z-GAL) to measure redshifts for 126 bright galaxies detected in theHerschelAstrophysical Large Area Survey (H-ATLAS), the HerMES Large Mode Survey (HeLMS), and theHerschelStripe 82 (HerS) Survey. We report reliable spectroscopic redshifts for a total of 124 of theHerschel-selected galaxies. The redshifts are estimated from scans of the 3 and 2-mm bands (and, for one source, the 1-mm band), covering up to 31 GHz in each band, and are based on the detection of at least two emission lines. Together with the Pilot Programme, where 11 sources had their spectroscopic redshifts measured, our survey has derived precise redshifts for 135 brightHerschel-selected galaxies, making it the largest sample of high-zgalaxies with robust redshifts to date. Most emission lines detected are from12CO (mainly fromJ = 2–1 to 5–4), with some sources seen in [CI] and H2O emission lines. The spectroscopic redshifts are in the range 0.8 &lt; z &lt; 6.55 with a median value ofz = 2.56 ± 0.10, centred on the peak epoch of galaxy formation. The linewidths of the sources are large, with a mean value for the full width at half maximum ΔVof 590 ± 25 km s−1and with 35% of the sources having widths of 700 km s−1 &lt; ΔV &lt; 1800 km s−1. Most of the sources are unresolved or barely resolved on scales of ∼2 to 3″ (or linear sizes of ∼15 − 25 kpc, unlensed). Some fields reveal double or multiple sources in line emission and the underlying dust continuum and, in some cases, sources at different redshifts. Taking these sources into account, there are, in total, 165 individual sources with robust spectroscopic redshifts, including lensed galaxies, binary systems, and over-densities. This paper presents an overview of thez-GAL survey and provides the observed properties of the emission lines, the derived spectroscopic redshifts, and a catalogue of the entire sample. The catalogue includes, for each source, the combined continuum and emission lines’ maps together with the spectra for each of the detected emission lines. The data presented here will serve as a foundation for the otherz-GAL papers in this series reporting on the dust emission, the molecular and atomic gas properties, and a detailed analysis of the nature of the sources. Comparisons are made with other spectroscopic surveys of high-zgalaxies and future prospects, including dedicated follow-up observations based on these redshift measurements, are outlined.

High-resolution emission spectroscopy retrievals of MASCARA-1b with CRIRES+: strong detections of CO, H2O, and Fe emission lines and a C/O consistent with solar

ABSTRACT The characterization of exoplanet atmospheres has proven to be successful using high-resolution spectroscopy. Phase curve observations of hot/ultra-hot Jupiters can reveal their compositions and thermal structures, thereby allowing the detection of molecules and atoms in the planetary atmosphere using the cross-correlation technique. We present pre-eclipse observations of the ultra-hot Jupiter, MASCARA-1b, observed with the recently upgraded CRIRES+ high-resolution infrared spectrograph at the VLT. We report a detection of Fe (≈ 8.3σ) in the K-band and confirm previous detections of CO (&amp;gt;15σ) and H2O (&amp;gt;10σ) in the day-side atmosphere of MASCARA-1b. Using a Bayesian inference framework, we retrieve the abundances of the detected species and constrain planetary orbital velocities, T–P profiles, and the carbon-to-oxygen ratio (C/O). A free retrieval results in an elevated CO abundance ($\log _{10}(\chi _{\rm {{}^{12}CO}}) = -2.85^{+0.57}_{-0.69}$), leading to a supersolar C/O ratio. More realistically, allowing for vertically-varying chemistry in the atmosphere by incorporating a chemical-equilibrium model results in a C/O of $0.68^{+0.12}_{-0.22}$ and a metallicity of $[\rm M/H] = 0.62^{+0.28}_{-0.55}$, both consistent with solar values. Finally, we also report a slight offset of the Fe feature in both Kp and vsys that could be a signature of atmospheric dynamics. Due to the 3D structure of exoplanet atmospheres and the exclusion of time/phase dependence in our 1D forward models, further follow-up observations and analysis are required to confirm or refute this result.

The Way of Water: ALMA Resolves H2O Emission Lines in a Strongly Lensed Dusty Star-forming Galaxy at z ∼ 3.1

We report Atacama Large Millimeter/submillimeter Array (ALMA) high-resolution (≲0.3″) observations of water emission lines p-H2O(202 − 111), o-H2O(321 − 312), p-H2O(422 − 413), in the strongly lensed galaxy HATLASJ113526.2-01460 at redshift z ∼3.1. From the lensing-reconstructed maps of water emission and line profiles, we infer the general physical properties of the interstellar medium (ISM) in the molecular clouds where the lines arise. We find that the water vapor lines o-H2O(321 − 312), p-H2O(422 − 413) are mainly excited by far-infrared (FIR) pumping from dust radiation in a warm and dense environment, with dust temperatures ranging from 70 to ∼100 K, as suggested by the line ratios. The p-H2O(202 − 111) line, instead, is excited by a complex interplay between FIR pumping and collisional excitation in the dense core of the star-forming region. This scenario is also supported by the detection of the medium-level excitation of CO resulting in the line emission CO (J = 8–7). Thanks to the unprecedented high resolution offered by the combination of ALMA capabilities and gravitational lensing, we discern the different phases of the ISM and locate the hot molecular clouds into a physical scale of ∼500 pc. We discuss the possibility of J1135 hosting an active galactic nucleus in its accretion phase. Finally, we determine the relation between the water emission lines and the total IR luminosity of J1135, as well as the star formation rate as a function of water emission intensities, comparing the outcomes to local and high-z galactic samples from the literature.

ATOMIUM: Probing the inner wind of evolved O-rich stars with new, highly excited H2O and OH lines

Context. Water (H2O) and the hydroxyl radical (OH) are major constituents of the envelope of O-rich late-type stars. Transitions involving energy levels that are rotationally or vibrationally highly excited (energies ≳4000 K) have been observed in both H2O and OH. These and more recently discovered transitions can now be observed at a high sensitivity and angular resolution in the inner wind close to the stellar photosphere with the Atacama Large Millimeter/submillimeter Array (ALMA). Aims. Our goals are: (1) to identify and map the emission and absorption of H2O in several vibrational states, and of OH in Λ-doubling transitions with similar excitation energies; and (2) to determine the physical conditions and kinematics in gas layers close to the extended atmosphere in a sample of asymptotic giant branch stars (AGBs) and red supergiants (RSGs). Methods. Spectra and maps of H2O and OH lines observed in a 27 GHz aggregated bandwidth and with an angular resolution of ~0."02−1."0 were obtained at two epochs with the main ALMA array. Additional observations with the Atacama Compact Array (ACA) were used to check for time variability of water transitions. Radiative transfer models of H2O were revisited to characterize masing conditions. Up-to-date chemical models were used for comparison with the observed OH/H2O abundance ratio. Results. Ten rotational transitions of H2O with excitation energies ~4000–9000 K were observed in vibrational states up to (υ1,υ2,υ3) = (0,1,1). All but one are new detections in space, and from these we have derived accurate rest frequencies. Hyperfine split Λ-doubling transitions in υ = 0, J = 27/2 and 29/2 levels of the 2Π3/2 state, as well as J = 33/2 and 35/2 of the 2Π1/2 state of OH with excitation energies of ~4780–8900 K were also observed. Four of these transitions are new detections in space. Combining our measurements with earlier observations of OH, the υ = 0 and υ = 1 Λ-doubling frequencies have been improved. Our H2O maps show compact emission toward the central star and extensions up to twelve stellar radii or more. The 268.149 GHz emission line of water in the υ2 = 2 state is time variable, tends to be masing with dominant radiative pumping, and is widely excited in AGBs and RSGs. The widespread but weaker 262.898 GHz water line in the υ2 = 1 state also shows signs of maser emission. The OH emission is weak and quasithermally excited. Emission and absorption features of H2O and OH reveal an infall of matter and complex kinematics influenced by binarity. From the OH and H2O column densities derived with nonmasing transitions in a few sources, we obtain OH/H2O abundance ratios of ~(0.7–2.8) × 10−2.

CO2 emission from soil irrigated with recycled wastewater at different levels and the relationships of emission with soil properties

The use of recycled wastewater in agricultural irrigation contributes to ecosystem by reducing the discharge of wastewater to the environment, as well as increasing soil quality with fertilizing effect. However, since the high nutrient of wastewater can make the soil a source of CO2 emission, it is necessary to know the relationships between CO2 emission and soil properties to the management of emissions. This study aimed to determine the relationships between CO2 emission and soil properties by examining the changes in the properties of soil irrigated with recycled wastewater and freshwater at different levels. The results showed that the recycled wastewater caused 58.1% more CO2 emissions than freshwater in full irrigation treatments, while the emissions decreased in the range of 8.8% to 44.5% with increased deficit irrigation. In addition, the significant relationships of CO2 emission with EC, pH, CaCO3, organic matter, total N, P2O5, K2O, cation exchange capacity, porosity, aggregate stability properties of the soil and H2O emission from the soil, soil moisture and temperature at different depths were determined, demonstrated the effectiveness of these parameters in the management of CO2 emissions in soil irrigated with recycled wastewater. Considering the obtained findings, it was determined that deficit irrigation is very effective in reducing CO2 emission and considering the effectiveness of soil temperature and soil properties on the emissions, CO2 emission can be reduced by soil temperature and soil properties management, and more comprehensive studies on this subject could suggest.