bluuebunny/crossref_metadata_2025 huggingface dataset:
New Breath Diagnostics for Fungal Disease
Authors: Diefenderfer Jenna , Bean Heather D. , Higgins Keppler Emily A.
Published: February 2024

Purpose of Review

Diagnosis of fungal disease etiology is often difficult, compounded by inaccurate or delayed diagnostic methods. Breath-based biomarkers are being investigated as a novel target for clinical diagnostics. This review aims to summarize recent advancements, identify gaps, and discuss future research directions for breath-based fungal diagnostics.

Recent Findings

Studies conducted in vitro, in animal models, and in human breath show fungi produce a large and diverse volatile metabolome. Recent studies on Aspergillus, Candida, Rhizopus, Coccidioides, Trichoderma, Fusarium, and Alternaria demonstrate the feasibility of identifying infectious etiology using fungal volatile profiles. However, the majority of data on fungal volatiles come from in vitro analyses, which have limited translatability to in vivo infections; thus, future studies should focus on in vivo volatile profiles to develop breath tests for diagnosing infections and monitoring antifungal therapy.

This review describes recent studies that examine volatile organic compounds (VOCs) as biomarkers to detect and differentiate pathogenic fungi, highlighting the feasibility of breath-based diagnostics for fungal disease.
Exploring Automatic Readability Assessment for Science Documents within a Multilingual Educational Context
Authors: Uçar Suna-Şeyma , Aldabe Itziar , Aranberri Nora , Arruarte Ana
Published: February 2024

Current student-centred, multilingual, active teaching methodologies require that teachers have continuous access to texts that are adequate in terms of topic and language competence. However, the task of finding appropriate materials is arduous and time consuming for teachers. To build on automatic readability assessment research that could help to assist teachers, we explore the performance of natural language processing approaches when dealing with educational science documents for secondary education. Currently, readability assessment is mainly explored in English. In this work we extend our research to Basque and Spanish together with English by compiling context-specific corpora and then testing the performance of feature-based machine-learning and deep learning models. Based on the evaluation of our results, we find that our models do not generalize well although deep learning models obtain better accuracy and F1 in all configurations. Further research in this area is still necessary to determine reliable characteristics of training corpora and model parameters to ensure generalizability.
Monodispersed biodegradable microparticles with wrinkled surface coated with silver nanoparticles for catalytic degradation of organic toxins
Authors: Chen Minjun , Bolognesi Guido , Begum Robina , Farooqi Zahoor H. , Vladisavljević Goran T.
Published: February 2024

Microfluidic fabrication of monodisperse microgels for biomedical, nanotechnological, environmental, and catalytic applications has become the subject of growing interest. In this work, monodisperse polyethylene glycol diacrylate [P(EGDA)] microgel particles were fabricated using a CNC-milled microfluidic device with a Lego-inspired interlocking mechanism. Silver nanoparticles (AgNPs) were synthesised and stabilised in situ on the wrinkled surface of the microgel particles using AgNO3 as a metal precursor and NaBH4 as a reductant. The loading of AgNPs (7.5 wt%) on microgel beads was confirmed by energy-dispersive X-ray spectroscopy, X-ray diffraction, and thermogravimetric analysis. Surface wrinkles were found to be a useful morphological feature acting as reservoirs for the accumulation of AgNPs. Ag–P(EGDA) hybrid polymer particles were shown to be an efficient catalyst for the reduction of 4-nitrophenol (4NP) into 4-aminophenol (4AP) by sodium borohydride at room temperature. After 40 min, 0.08 M 4NP was completely converted into 4AP using 2.1 mg/mL of Ag–P(EGDA) catalytic particles, and the reaction followed a pseudo-first-order kinetics. The apparent rate constant increased from 0.0142 to 0.117 min−1 when the loading of catalytic particles increased from 1.7 to 2.50 mg/mL indicating that the reduction is occurring on the catalyst surface according to the Langmuir–Hinshelwood model. Ag–P(EGDA) hybrid microgel was a potent and recyclable catalyst for room-temperature degradation of methylene blue (MeB) by NaBH4. At the Ag–P(EGDA) loading of 2.0 mg/mL, 25 µM of MeB was completely degraded in 6 min. Composite Ag–P(EGDA) microgel beads can be used as an eco-friendly and easily recoverable catalyst for the transformation of other organic pollutants into useful chemicals.

Graphical abstract
Translating a Culture of Quality to Clinical Research Conduct: Expanding the Clinical Development Quality Framework
Authors: Torok Michael , Sam Leslie , Hebert Jennifer
Published: February 2024

The International Council on Harmonisation E8 Guidance Revision 1 (ICH E8(R1)) calls for creating a Culture of Quality that “values and rewards critical thinking and open, proactive dialogue about what is critical to quality.” Across the biopharma landscape, clinical sites, sponsors, and service providers are working to translate this far-reaching guideline into working practices. This manuscript deconstructs key elements that comprise the critical thinking and open, proactive Culture of Quality “enablers.” In addition, maturity models are provided so readers can visualize what a Culture of Quality looks like in their clinical research organization. These provide examples of high performing cultures of quality and useful tools for teams or organizations to measure and evolve their respective quality cultures.
Water Maser Zeeman Splitting in the Ionized Jet IRAS 19035+0641 A
Authors: Rodríguez Tatiana M. , Momjian Emmanuel , Hofner Peter , Sarma Anuj P. , Araya Esteban D.
Published: February 2024

A key ingredient in the earliest evolutionary phase of high-mass (M>8 M⊙) star formation (HMSF) is the presence of a jet/outflow system. To study its role in HMSF, we have carried out high resolution (0.1″) VLA K-band (18-26.5 GHz) observations toward IRAS 19035+0641 A, identified as a high-mass protostellar jet candidate based on previous cm continuum data. Our observations resolve the continuum emission into an elongated structure in the NE-SW direction, confirming that the K-band continuum arises from an ionized jet. Furthermore, we detected several 22.2 GHz H2O maser spots aligned in a direction consistent with the jet axis. Zeeman splitting was detected in the strongest maser spot. In this paper, we present our results and discuss the implications of our findings.
Water Fountain Sources Monitored in FLASHING
Authors: Imai Hiroshi , Amada Kei , Gómez José F. , Uscanga Lucero , Tafoya Daniel , Nakashima Keisuke , Shum Ka-Yiu , Hamae Yuhki , Burns Ross A. , Shibata Yosuke , Kasai Rina , Takashima Miki , Orosz Gabor
Published: February 2024

We have investigated the spectral evolutions of H2O and SiO masers associated with 12 “water fountain” sources in our FLASHING (Finest Legacy Acquisitions of SiO-/H2O-maser Ignitions by Nobeyama Generation) project. Our monitoring observations have been conducted using the Nobeyama 45 m telescope every 2 weeks–2 months since 2018 December except during summer seasons. We have found new extremely high velocity H2O maser components, breaking the records of jet speeds in this type of sources. Systematic line-of-sight velocity drifts of the H2O maser spectral peaks have also been found, indicating acceleration of the entrained material hosting the masers around the jet. Moreover, by comparing with previous spectral data, we can find decadal growths/decays of H2O maser emission. Possible periodic variations of the maser spectra are further being inspected in order to explore the periodicity of the central stellar system (a pulsating star or a binary). Thus we expect to see the real-time evolution/devolutions of the water fountains over decades.
Maser science with the next generation Very Large Array (ngVLA)
Authors: Hunter Todd R.
Published: February 2024

Imaging the bright maser emission produced by the various molecular species from 1.6 to 116 GHz provides a way to probe the kinematics of dense molecular gas at high angular resolution. Unimpeded by the high dust optical depths that affect shorter wavelength (sub)mm observations, the high brightness temperature of these emission lines have become an essential tool for understanding the process of massive star formation. Operating from 1.2–116 GHz, the next generation Very Large Array (ngVLA) of 263 antennas will provide the capabilities needed to fully exploit these powerful tracers, including the ability to resolve accretion and outflow motions down to scales as fine as ∼1-10 au in deeply embedded Galactic star-forming regions, and at sub-pc scales in nearby galaxies. I will summarize the proposed specifications of the ngVLA, describe the current status of the project, and offer examples of future experiments designed to image the vicinity of massive protostars in continuum, thermal lines, and maser lines simultaneously.
Nascent planetary nebulae: new identifications and extraordinary evolution
Authors: Cala Roldán A. , Gómez José F. , Miranda Luis F.
Published: February 2024

Planetary nebulae (PNe) harbouring masers of H2O (H2OPNe) and/or OH (OHPNe) are thought to be nascent PNe. They are extremely scarce, and so far only eight members are know to date. Here we explain our current effort to identify new H2OPNe and/or OHPNe. We report IRAS 07027–7934 as a new bona fine OHPN. Its 1612 MHz OH spectrum seems to be changing from double- to single-peaked since the redshifted emission has vanished almost completely, and the 1667 MHz OH maser emission has disappeared. For the OHPN Vy 2-2, we found that its central star is unexpectedly carbon (C)-rich, has a low-mass progenitor, and could be a post-common envelope binary system. Moreover, we confirm Vy 2-2 as a nascent PN. We speculate that low-mass C-rich central stars in post-common envelope systems could be a common end of H2OPNe and OHPNe.
The loss of OH maser emission in the early stage of Post-AGB evolution
Authors: Etoka S. , Engels D. , Ullrich T. , González J.B. , López-Martí B.
Published: February 2024

Based on the results of an on-going monitoring program of 1612 MHz OH masers in OH/IR stars, we determined a lifetime encompassing late AGB and early post-AGB evolution of at least 4500 years. Fading of the OH masers observed with the Nançay Radio Telescope is detected in several post-AGB OH/IR stars on timescales of decades, while AllWISE/NEOWISE light curves taken almost in parallel show diverse behaviours.
Preliminary results on SiO maser emission from the AGB binary system: R Aqr.
Authors: Desmurs J.-F. , Alcolea J. , Bujarrabal V. , Santander Garcia M. , Gomez-Garrido M. , Mikolajewska J.
Published: February 2024

Binary/multiple stellar systems are as abundant as single stars. They are very interesting cosmic laboratories as they are related to many astrophysical phenomena. In the case of AGB (and post-AGB) stars, binaries are the most likely explanation for the shaping of non spherical PNe, a long standing problem in stellar evolution. While many binaries are known in the PNe phase, there are few examples in the previous AGB phase. Hydrodynamical models of the binary interaction are available, but well known parameters for orbits are non-existent. We observed the AGB binary system R Aqr at 7 mm using the Global VLBI array in wide-band continuum and SiO masers. The strong SiO masers were used to self-calibrate the observations and pinpoint the location of the AGB component. We used the continuum to try to directly detect the WD companion or its close environments (non-thermal emission from accretion disks/jets). We present our preliminary results for R Aqr on the relative positions of the J=1−0 SiO masers (v=1) with respect to the white dwarf position. This opens a new way to determine orbits in binaries at the AGB phase and better study their role in late stellar evolution and PNe shaping.
A Profile-based Approach to Finding New Water Fountain Candidates using Databases of Circumstellar Maser Sources
Authors: Nakashima J. , Fan H. , Engels D. , Zhang Y. , Qiu J.-J. , Feng H.-X. , Xie J.-Y. , Imai H. , Hsia C.-H.
Published: February 2024

Water fountains (WFs) are thought to represent an early stage in the morphological evolution of circumstellar envelopes surrounding low- and intermediate-mass evolved stars. These objects are considered to transition from spherical to asymmetric shapes. Despite their potential importance in this transformation process of evolved stars, there are only a few known examples. To identify new WF candidates, we used databases of circumstellar OH (1612 MHz) and H2O (22.235 GHz) maser sources, and compared the velocity ranges of the two maser lines. Finally, 41 sources were found to have a velocity range for the H2O maser line that exceeded that of the OH maser line. Excluding known planetary nebulae and after reviewing the maser spectra in the original literature, we found for 11 sources the exceedance as significant, qualifying them as new WF candidates.
What’s behind the corner: Maser emission in nearby and distant galaxies with the new radio facilities
Authors: Tarchi Andrea , Castangia Paola , Surcis Gabriele , Ladu Elisabetta , Bannikova Elena Yu
Published: February 2024

Extragalactic maser sources are unique tools to derive fundamental physical quantities of the host galaxies, e.g, geometry of accretion disks around super-massive black holes and precise black hole masses, and study in detail the interaction region of nuclear jets/outflows with the interstellar medium, in nearby and distant Active Galactic Nuclei. So far, however, extragalactic maser searches have yielded detection of few percent, and only relatively few maser sources have been found. Because of their unprecedented sensitivity, new upcoming facilities, like the SKA and the ngVLA, will allow to significantly increase the number of known (water) maser sources. This will lead to the chance of performing statistically-relevant studies of the maser phenomenon (and its occurrence), derive extragalactic masers luminosity functions, and ultimately (in particular, through the aid of longer-baselines arrays options) to perform the studies described above for larger samples and up to cosmological distances.
Water maser flare and potential accretion burst in NGC 2071-IR
Authors: Dzodzomenyo Andrews , Chibueze James O. , van den Heever Stefanus
Published: February 2024

We monitored 22 GHz water masers in NGC 2071-IR using the Hartebeesthoek 26-m telescope and identified a significant flare (up to 4722 Jy) originating from the 14.4 km s-1 feature associated with the protostellar core NGC 2071-IRS1. To determine if the maser flare resulted from an accretion burst, we analyzed related signatures such as simultaneous flaring of other maser species and an increase in infrared luminosity. Near-infrared (Ks-band) observations conducted on 28 December 2019 during the flare, using the Kanata/HONIR telescope, exhibited a 0.2 magnitude increase in comparison to the 2MASS magnitude obtained from observations conducted on 10 October 1999. However, our findings indicate that the flare was attributed to mechanisms other than an accretion burst.
Water masers associated with AGN in radio galaxies
Authors: Sawada-Satoh Satoko
Published: February 2024

We present dual-frequency VLBI observations of a nearby radio galaxy NGC 4261 at 22 and 43 GHz using the East Asia VLBI Network. In particular, the first sub-pc scale image of the 22 GHz water megamaser line in the circumnuclear region of NGC 4261 is shown. Our results suggest that the megamaser emission in NGC 4261 can be associated with the inner radius of the obscuring disk, as it is proposed for the nearest radio-loud megamaser source NGC 1052. An alternative hypothesis on the megamaser association is the shock region of the interaction between the jet and ambient molecular clouds.
Patterns in water maser emission of evolved stars on the timescale of decades
Authors: Brand Jan , Engels Dieter , Winnberg Anders
Published: February 2024

We present our past and current long-term monitoring program of water masers in the circumstellar envelopes of evolved stars, augmented by occasional interferometric observations. Using as example the Mira-variable U Her, we identify three types of variability: periodic (following the optical variation), long-term (years-decades) and short-term irregular (weeks-months). We show there are regions in the maser shell where excitation conditions are favourable, which remain stable for many years. Lifetimes of maser clouds in the wind-acceleration zone are of the order of up to a few years. Much longer lifetimes are found for the peculiar case of a maser cloud outside that zone (as in RT Vir), or in some cases where the motion of spectral features can be followed for the entire 2 decade monitoring period (as in red supergiant VX Sgr).
Interferometric Observations of the Water Fountain Candidates OH 16.3−3.0 and IRAS 19356+0754
Authors: Chacón P. , Uscanga L. , Imai H. , Yung B. H. K. , Gómez J. F. , Rizzo J. R. , Suárez O. , Miranda L. F. , Anglada G. , Torrelles J. M.
Published: February 2024

Water Fountains (WFs), located between the AGB and PN phases of stellar evolution, may provide significant clues on the shaping process of PNe. We present new VLA observations of the WF candidates OH 16.3-3.0 and IRAS 19356+0754. We detect H2O and OH maser and radio continuum emission towards OH 16.3-3.0. We suggest that the OH maser emission of OH 16.3-3.0 is associated with an aspherical circumstellar envelope due to its spatio-kinematics and peculiar spectral profile. We could not confirm the candidates as bona fide WFs because of the narrow velocity spread (OH 16.3-3.0) or non-detection (IRAS 19356+0754) of H2O maser emission. Further monitoring could help to discern their nature.
Results of KVN Key Science Program for evolved stars
Authors: Yun Youngjoo , Cho Se-Hyung , Yoon Dong-Hwan , Yang Haneul , Dodson Richard , Rioja María J. , Imai Hiroshi
Published: February 2024

We present the results of KVN Key Science Program (KSP) for evolved stars, which was launched in 2014. The first phase of KSP ended in June 2020 and the second phase started in October 2020. The goal of KSP is to study the physical characteristics of the evolved stars by observing the spatial distribution and temporal variability of the stellar masers at four frequency-bands (K, Q, W and D bands). The 22 GHz H2O maser is usually observed from the outer part of circumstellar envelopes compared to the 43, 86, 129 GHz SiO masers, thus the kinematic links between these regions can be studied by the multi-frequency simultaneous observations of KSP along the stellar pulsation cycles. This eventually enable us to study the enormous mass-loss rate of evolved stars, and the accumulated results from KSP are expected to shed light on the study of the late stage of the stellar evolution.
A sensitive search for SiO maser emission in planetary nebulae
Authors: Gómez José F. , Cala Roldán A. , Miranda Luis F. , Imai Hiroshi , Osorio Mayra , Anglada Guillem
Published: February 2024

Eight planetary nebulae (PNe) are known to emit OH and/or H2O masers, but there is no report of an SiO maser in this type of objects. We present a search for SiO masers in 16 confirmed and candidate PNe, carried out with the Australia Telescope Compact Array. We found no evidence of association between SiO masers and PNe in our data. Previous detections of thermal SiO emission in PNe show that these molecules can be present in gas phase in this type of objects, but it is not yet clear whether they can be found where the physical conditions are appropriate for maser pumping. We suggest that the best candidates for a new search would be PNe showing high-velocity outflows.
Kinematics in the Galactic Center with SiO masers
Authors: Paine Jennie , Darling Jeremy
Published: February 2024

Stellar SiO masers are found in the atmospheres of asymptotic giant branch (AGB) stars with several maser transitions observed around 43 and 86 GHz. At least 28 SiO maser stars have been detected within ∼2 pc projected distance from Sgr A* by the Very Large Array (VLA) and Atacama Millimeter/submillimeter Array (ALMA). A subset of these masers have been studied for several decades and form the basis of the radio reference frame that anchors the reference frame for infrared stars in the Galactic Center (GC). We present new observations of the GC masers from VLA and ALMA. These new data combined with extant maser astrometry provide 3D positions, velocities, and acceleration limits. The proper motions and Doppler velocities are measured with unprecedented precision for these masers. We further demonstrate how these measurements may be used to trace the stellar and dark matter mass distributions within a few pc of Sgr A*.
Fully 3D modelling of masers towards AGB stars - latest development and early results
Authors: Pimpanuwat B. , M. D.  , Gray  , S.  , Etoka  , W.  , Homan  , A. M. S.  , Richards
Published: February 2024

We present new results from a 3D modelling code for maser flares which provides the user with control over the physical conditions; maser cloud geometry and orientation; and fast runtime via parallelisation. The statistics of simulated observables suggest that achievable amplification may be dependent on viewpoints of the source and that a randomly placed observer is likely to detect an unremarkable blue- or red-shifted maser unless the line-of-sight direction is optimal for maser amplification. A preliminary model of masers towards π1 Gru based on SPH simulations also shows promising consistency with ALMA observations of high-j SiO transitions from the source.
Monitoring of the polarized H2O maser emission around the massive protostars W75N(B)-VLA 1 and W75N(B)-VLA 2
Authors: Surcis Gabriele , Vlemmings Wouter H.T. , Goddi Ciriaco , Torrelles José-María
Published: February 2024

Several radio sources have been detected in the high-mass star-forming region W75N(B), among them the massive young stellar objects VLA 1 and VLA 2 are of great interest. These are thought to be in different evolutionary stages. In particular, VLA 1 is at the early stage of the photoionization and it is driving a thermal radio jet, while VLA 2 is a thermal, collimated ionized wind surrounded by a dusty disk or envelope. In both sources 22 GHz H2O masers have been detected in the past. Those around VLA 1 show a persistent linear distribution along the thermal radio jet and those around VLA 2 have instead traced the evolution from a non-collimated to a collimated outflow over a period of ∼20 years. The magnetic field inferred from the H2O masers showed a rotation of its orientation according to the direction of the major-axis of the shell around VLA 2, while it is immutable around VLA 1.

We further monitored the polarized emission of the 22 GHz H2O masers around both VLA 1 and VLA 2 over a period of six years with the European VLBI Network for a total of four epochs separated by two years from 2014 to 2020. We here present the results of our monitoring project by focusing on the evolution of the maser distribution and of the magnetic field around the two massive young stellar objects.
SiO maser line ratios in the BAaDE Survey
Authors: Lewis Megan O. , Pihlström Ylva M. , Sjouwerman Loránt O.
Published: February 2024

Multi-transition SiO maser emission has been detected in over 10 thousand evolved stars across the plane of the Milky Way by the Bulge Asymmetries and Dynamical Evolution (BAaDE) survey. In addition to the large source catalog of the survey, the frequency coverage is also unprecedented: the J=1-0 (43 GHz) data cover seven separate transitions of SiO, and the J=2-1 (86 GHz) data cover ten SiO transitions. In contrast, most other SiO maser data only probe the SiO v=1 and v=2 at 43 GHz and/or the v=1 at 86 GHz. Our extended range allows for the derivation of SiO line ratios for a huge population of evolved stars, including those derived from rare transitions associated with 29SiO and 30SiO isotopologues. We examine how these ratios are affected by the specific combinations of transitions that are detected in a single source. Furthermore, we present a class of ‘isotopologue dominated’ sources where the 29SiO transitions are the brightest in the 43 GHz spectrum. Finally, using Optical Gravitational Lensing Experiment (OGLE) light curves of our maser stars, changes in line ratios as a function of stellar phase are discussed.
The origin of the Perseus-arm gap revealed with VLBI astrometry
Authors: Sakai Nobuyuki , Nakanishi Hiroyuki , Kurahara Kohei , Sakai Daisuke , Hachisuka Kazuya , Kim Jeong-Sook , Kameya Osamu
Published: February 2024

The Perseus arm has a gap in Galactic longitudes (l) between 50° and 80° where the arm has little star formation activity. To understand the gap, we conducted VERA (VLBI Exploration of Radio Astrometry) astrometry and analyzed archival H I data. We report on parallax and proper motion results from four star-forming regions, of which G050.28–00.39 and G070.33+01.59 are associated with the gap. Perseus-arm sources G049.41+00.32 and G050.28–00.39 lag relative to a Galactic rotation by 77 ± 17 km s-1 and 31 ± 10 km s-1, respectively. The noncircular motion of G049.41+00.32 cannot be explained by the gravitational potential of the arm. We discovered rectangular holes with integrated brightness temperatures less than 30 K arcdeg in l vs. VLSR of the H I data. Also, we found extended H I emission on one side of the Galactic plane when integrating the H I data over the velocity range covering the hole. G049.41+00.32 and G050.28–00.39 are moving toward the emission. The Galactic H I disk at the same velocity range showed an arc structure, indicating that the disk was pushed from the lower side of the disk. All the observational results might be explained by a cloud collision with the Galactic disk.
ALMA explores the inner wind of evolved O-rich stars with two widespread vibrationally excited transitions of water
Authors: Baudry Alain , Wong Ka Tat , Etoka Sandra , Richards Anita M.S. , Gray Malcolm D. , Herpin Fabrice , Danilovich Taïssa , Wallström Sofia , Decin Leen , Gottlieb Carl A. ,   the ATOMIUM consortium
Published: February 2024

ALMA observations with angular resolution in the range ∼20–200 mas demonstrate that emission at 268.149 and 262.898 GHz in the (0,2,0) and (0,1,0) vibrationally excited states of water are widespread in the inner envelope of O-rich AGB stars and red supergiants. These transitions are either quasi-thermally excited, in which case they can be used to estimate the molecular column density, or show signs of maser emission with a brightness temperature of ∼103–107 K in a few stars. The highest spatial resolution observations probe the inner few stellar radii environment, up to ∼10–12 R* in general, while the mid resolution data probe more thermally excited gas at larger extents. In several stars, high velocity components are observed at 268.149 GHz which may be caused by the kinematic perturbations induced by a companion. Radiative transfer models of water are revisited to specify the physical conditions leading to 268.149 and 262.898 GHz maser excitation.
Methanol and excited OH masers in W49N as observed using EVN
Authors: Bartkiewicz Anna , Szymczak Marian , Kobak Agnieszka , Aramowicz Mirosława
Published: February 2024

We imaged the excited OH maser line at 6.035 GHz associated with the 6.7 GHz methanol masers in a selected sample of high-mass young stellar objects using the European VLBI Network. The excited OH emission was found in a survey of methanol maser sources carried out since 2018 with the Torun 32-m telescope. The overlap of radial velocities of spectral features of methanol and excited OH suggested that both lines arose in the same volume of gas, therefore, we verified this hypothesis with the interferometric data. Here, we present the first images at the milliarcsecond scale of both maser transitions and identify the Zeeman pairs at the ex-OH line estimating the strength of the magnetic field in G43.149+00.013 (W49N).
Study of Active Galactic Nuclei using the Water Vapour Masers
Authors: Deepshikha  , Naomasa Nakai , Madoka Yamazaki , Aya Yamauchi
Published: February 2024

The mass of the black hole separated from the mass of the maser disk is calculated using the mega-maser technique for 15 maser-galaxies and the corresponding Magorrian relationship (inline1) is analysed.
A database of circumstellar OH masers update
Authors: Engels Dieter , López-Martí Belen
Published: February 2024

The database of circumstellar OH masers by Engels & Bunzel (2015) was updated to include new 1612, 1665, and 1667 MHz OH maser observations published between 2015 and 2022. A cross-correlation of the database was made with infrared catalogues (AllWISE and 2MASS) and with GAIA DR3. This led frequently to significantly improved coordinates and identified contaminations with non-stellar sources. About 40% of all OH maser-detected stars were not detected by GAIA. These are mostly representatives of the population of highly obscured stars at the end of AGB or at the beginning of post-AGB evolution.
Galactic Astrometry with VLBI
Authors: Rygl Kazi L. J.
Published: February 2024

Astrometric very long baseline interferometry (VLBI) observations of stellar masers are an excellent method to determine distances and proper motions in our Galaxy. Large maser astrometry surveys, the Bar and Spiral Structure Legacy survey and the VLBI Exploration for Radio Astrometry, allowed astronomers to determine fundamental Galactic parameters, such as the rotation curve and the distance to the Galactic centre, as well as to trace the spiral arms. In this review, the results of these surveys will be summarised and compared with astrometric measurements using other methods.
The Astrometric Animation of Water Masers toward the Mira Variable BX Cam
Authors: Xu Shuangjing , Imai Hiroshi , Yun Youngjoo , Zhang Bo , Rioja María J. , Dodson Richard , Cho Se-Hyung , Kim Jaeheon , Cui Lang , Sobolev Andrey M. , Chibueze James O. , Kim Dong-Jin , Amada Kei , Nakashima Jun-ichi , Orosz Gabor , Oyadomari Miyako , Oh Sejin , Yonekura Yoshinori , Sun Yan , Mai Xiaofeng , Zhang Jingdong , Wen Shiming , Jung Taehyun
Published: February 2024

We report VLBI monitoring observations of the 22 GHz H2O masers toward the Mira variable BX Cam. Data from 37 epochs spanning ∼3 stellar pulsation periods were obtained between May 2018 and June 2021 with a time interval of 3–4 weeks. In particular, the VERA dual-beam system was used to measure the kinematics and parallaxes of the H2O maser features. The obtained parallax, 1.79±0.08 mas, is consistent with Gaia EDR3 and previous VLBI measurements. The position of the central star was estimated relied on Gaia EDR3 data and the center position of the 43 GHz SiO maser ring imaged with KVN. Analysis of the 3D maser kinematics revealed an expanding circumstellar envelope with a velocity of 13±4 km s−1 and significant spatial and velocity asymmetries. The H2O maser animation achieved by our dense monitoring program manifests the propagation of shock waves in the circumstellar envelope of BX Cam.
Maser Tracers of Gas Dynamics near Young Stars New Perspectives
Authors: Sanna Alberto , Moscadelli Luca
Published: February 2024

The protostellar environment where young stars form has physical conditions suitable to excite a number of molecular maser lines that have traditionally provided an unique probe of star formation kinematics, at the highest angular resolution of radio very long baseline interferometry (VLBI) observations. In the following, we will discuss a number of recent results on our understanding of the gas dynamics traced by masers in the vicinity of young forming stars. These findings provide direct clues on how our community can substantially contribute to the field of star formation in the next decade.
Estimating distances to AGB stars using IR data
Authors: Bhattacharya Rajorshi , Pihlström Ylva M. , Sjouwerman Loránt O.
Published: February 2024

We present a method to estimate distances to AGB stars, utilizing the rich infrared data sets available for these infrared-bright targets. The method is based on the assumption that stars with intrinsically similar properties (metallicity, initial mass, etc.) produce similar spectral energy distributions (SEDs) and similar luminosities. We here discuss the results for AGB stars belonging to the BAaDE survey sample whose distances were calibrated using the template SEDs of stars with their VLBI parallaxes. As VLBI parallaxes are only known for a handful of sources, the resulting templates only cover a small subset of the BAaDE sample. Additional methods to derive suitable templates will therefore also be required. The work on expanding the template set is promising, although more fine tuning is still needed.
HINOTORI and Maser Observations
Authors: Nakashima Keisuke , Shum Ka-Yiu , Imai Hiroshi ,   HINOTORI Collaboration
Published: February 2024

HINOTORI (Hybrid Integration Project in Nobeyama, Triple-band Oriented) has constructed a higher sensitivity 22/43 GHz and a 22/43/86 GHz simultaneous observation systems in the Nobeyama 45-m telescope by introducing new frequency separation filters in the telescope’s quasi-optics. The performance of the observation systems, such as the beam squint, the aperture efficiency, the system noise temperature when inserting the filters, and the phase stability of the signal path have been evaluated. It is indicated that the established systems have sufficient performance for single-dish and VLBI observations. The single-dish observation demonstrations using the triple-band system were successfully conducted in acquiring scientific data including multiple maser lines.
Trigonometric parallax, proper motion, and structure of three southern hemisphere methanol masers
Authors: Hyland Lucas J. , Ellingsen Simon P. , Reid Mark J. , Kumar Jayender , Orosz Gabor
Published: February 2024

We present the trigonometric parallax, proper motion, and structure of three methanol masers from the Southern Hemisphere Parallax Interferometric Radio Astrometry Legacy Project (SπRALS). All three masers have better than 5% parallax accuracy, which we attribute to the new inverse MultiView calibration technique.
Properties of pulsating OH/IR stars revealed from astrometric VLBI observation
Authors: Nakagawa Akiharu , Kurayama Tomoharu , Sudou Hiroshi , Orosz Gabor
Published: February 2024

We aim to reveal properties of evolution stages in AGB phase; Mira, OH/IR stars, and non-variable OH/IR stars. We presented results of our VLBI observations of four stars; NSV17351, OH39.7+1.5, IRC–30363, and AW Tau. We used the VERA VLBI array to observe 22 GHz H2O masers. Parallaxes of the four sources were obtained to be 0.247±0.035 mas (4.05±0.59 kpc), 0.54±0.03 mas (1.85±0.10 kpc), 0.562±0.201 mas (1.78±0.73 kpc), and 0.449±0.032 mas (2.23±0.16 kpc). Determination of pulsation period of NSV17351 was done for the first time. We revealed the position and kinematics of NSV17351 in our Galaxy and found that NSV17351 is located in an interarm region. A new period-magnitude relationship was indicated in the infrared region. Various other properties based on the distance measurements are also discussed. We have to emphasize that the VLBI astrometry is effective and the only way for parallax measurements of dust obscured OH/IR stars.
Sub-mm spectral astrometric VLBI with the ngEHT
Authors: Dodson Richard , Rioja Maria J.
Published: February 2024

We present the prospects from astrometric spectral line VLBI in the era of ngEHT. We review the potential targets, that span many interesting science cases. We summarise the approaches that have been demonstrated to work at lower frequencies and touch on the simulations that give us great confidence that these same approaches will continue to work at sub-mm wavelengths. We conclude that this is a worthwhile pursuit with a high probability of success.
Water masers high resolution measurements of the diverse conditions in evolved star winds
Authors: Richards A. M. S. , Asaki Y. , Baudry A. , Brand J. , Decin L. , Etoka S. , Gray M. D. , Herpin F. , Humphreys R. , Pimpanuwat B. , Singh A. P. , Yates J. A. , Ziurys L. M.
Published: February 2024

We compare detailed observations of multiple H2O maser transitions around the red supergiant star VY CMa with models to constrain the physical conditions in the complex outflows. The temperature profile is consistent with a variable mass loss rate but the masers are mostly concentrated in dense clumps. High-excitation lines trace localised outflows near the star.
Astrometric observations of water maser sources toward the Galactic Center with VLBI
Authors: Sakai Daisuke , Oyama Tomoaki , Kobayashi Hideyuki , Honma Mareki
Published: February 2024

The Central Molecular Zone (CMZ) in the Galactic Center region shows outstanding non-circular motion unlike the Galactic disk. While several models describing this non-circular motion have been proposed, a uniform kinematic model of the CMZ orbit has not yet emerged. To uncover the dynamics of the Galactic center region, we conducted VLBI astrometric observations of 22GHz water maser sources towards the Galactic center using VERA. By measuring parallaxes and proper motions, we can determine whether each source is actually located in the CMZ or not, and identify the three-dimensional positions and velocities in the non-circular orbit if the source is indeed located in the CMZ. We present the results of our astrometric study for several maser sources associated with molecular clouds towards the Galactic center. The astrometric observations toward Sgr B2(M) indicated that Sgr B2 complex is moving toward the positive Galactic longitude relative to Sgr A*.
Observations of Possibly New OH Excited Rotational State Masers
Authors: Shmeld Ivar , Aberfelds Artis , Patoka Oleksey
Published: February 2024

In order to search for new 6.035 GHz excited OH masers 272 star-forming regions visible from the northern hemisphere with known active methanol masers were observed with the 32 m and 16 m radio telescopes of the Ventspils International Radio Astronomy Center (VIRAC). Three possibly new excited OH maser sources at 6.035 GHz were seen.
OH megamaser emission in the outflow of the luminous infrared galaxy Zw049.057
Authors: Aalto Susanne , Lankhaar Boy , Wethers Clare , Moldon Javier , Beswick Robert
Published: February 2024

High resolution (0."26 × 0."13 (70 × 35 pc)) L-band (18 cm) OH megamaser (OHM) e-Merlin observations of the LIRG Zw049.057 show that the emission is emerging from a low velocity outflowing structure - which is foreground to a fast, dense and collimated molecular outflow detected by ALMA. The extremely dusty compact obscured nucleus (CON) of Zw049.057 has no (or only little) OHM emission associated with it - possibly because of too high number densities that quench the OHM. In contrast we detect 6 cm H2CO emission primarily from the CON-region. We suggest that the OHM-region of Zw049.057 is not directly associated with star formation, but instead occurs in a wide-angle, slow outflow that surrounds the fast and dense outflow. The OHM is pumped by IR emission that likely stems from activities in the nucleus. We briefly discuss how OHM emission can be used as a probe of LIRG-CON galaxies.
Jet and Outflows in Massive Star Forming Region: G10.34-0.14
Authors: Kang Jihyun , Kim Mikyoung , Kim Kee-Tae , Hirota Tomoya ,   KaVA SF team
Published: February 2024

The ALMA observations of the high-mass star-forming region G10.34-0.14 reveal the existence of three massive hot cores. The most massive of these cores, core S1, exhibits both high and low-velocity jet/outflow in the CO, SiO, and CH3OH. It is associated with water and Class I methanol masers. The core N shows a low-velocity CO outflow and is associated with an Extended Green Object, along with Class I and II methanol masers. The characteristics of the outflows and masers in these two cores suggest they are in different stage of evolution and varying physical conditions.
HMSFR G024.33+0.14: A possible new discovery in the making
Authors: van den Heever S. P. , Szymczak M. , Durjasz M. , Bartkiewicz A. , Olech M. , Wolak P.
Published: February 2024

Since 2017, and the formation of the maser monitoring organisation (M2O), we have observed several intriguing events. These events have included possible accretion bursts, strong jets, periodicity after a flare, a heat-wave of radiation travelling outward at a fraction of the speed of light, to name a few. In September 2019 the M2O was notified of another source showing flaring behavior, and here we present the possibility of the first discovery of long-term maser periodicity from the high-mass star formation region (HMSFR) G024.33+0.14, with a period of about 3000 days.
Discovery of circular polarization of the 6.7 GHz methanol maser in G33.641-0.228
Authors: Fujisawa Kenta
Published: February 2024

The 6.7 GHz methanol maser emitted by a high-mass star forming region G33.641-0.228 is known to exhibit fast flux density variability on timescales of less than one day. The mechanism of this variability, called burst, has not been known. We observed the circular polarization of this maser. As a result, we found that only the spectral components representing burst exhibit strong circular polarization exceeding 10%. This suggests that the two phenomena of the burst and circular polarization are related to each other.
Intensity monitor of water maser emission associated with massive YSOs
Authors: Sunada Kazuyoshi , Hirota Tomoya , Kim Mikyoung , Burns Ross
Published: February 2024

We are carrying out the intensity monitoring of the water maser emission associated with massive young stellar objects (YSOs) using the VLBI Exploration of Radio Astrometry (VERA) antennas. We are currently monitoring 108 sources. During our long monitoring period, we could find flares on several YSOs. As an example, we show the results from IRAS 16293–2422 and NGC2071 IRS1 here. We also show the results of monitoring of the water maser emission from G36.115+0.552, which the methanol maser flare was reported. We observed it as often as possible, usually once a day.
Assessment of Chalk as an Archive for the Lithium Isotope Composition of Seawater
Authors: Huber Sandra J. , Schlidt Vanessa , Seitz H.‐Michael , Kniest Jorit F. , Raddatz Jacek , Marschall Horst R. , Voigt Silke
Published: February 2024

The understanding of silicate weathering and its role as a sink for atmospheric CO2 is important to get a better insight into how the Earth shifts from warm to cool climates. The lithium isotope composition (δ7Li) of marine carbonates can be used as a proxy to track the past chemical weathering of silicates. A high‐resolution δ7Li record would be helpful to evaluate the role of silicate weathering during the late Cretaceous climate cooling. Here, we assess chalk as a potential archive for reconstructing Late Cretaceous seawater Li isotope composition by comparing Maastrichtian chalk from Northern Germany (Hemmoor, Kronsmoor) to a Quaternary coccolith ooze from the Manihiki Plateau (Pacific Ocean) as a lithological analog to modern conditions. We observe a negative offset of 3.9 ± 0.6‰ for the coccolith ooze relative to the modern seawater Li isotope composition (+31.1 ± 0.3‰; 2SE; n = 54), a value that falls in the range of published offsets for modern core‐top samples and for brachiopod calcite. Further, the negative offset between the Li isotope compositions of Manihiki coccolith ooze and modern planktonic foraminifera is 2.3 ± 0.6‰. Although chalk represents a diagenetically altered modification of pelagic nannofossil ooze, manifested by changes in the composition of trace elements, we observe a consistent offset of Li isotope data between Maastrichtian chalk and Maastrichtian planktonic foraminiferal data (−1.4 ± 0. 5‰) that lies within the uncertainty of modern values. We therefore suggest that chalk can be used as a reliable archive for δ7Li reconstructions.
Extracting Meaningful Environmental and Age Information From a c. 2.4–2.2 Ga Peritidal Phosphorite: The Turee Creek Group, Western Australia
Authors: Soares Georgia G. , Garber Joshua M. , House Christopher H. , Reimink Jesse R.
Published: February 2024

Phosphorites can record oceanic conditions during their deposition, but the faithful retention of primary information in Paleoproterozoic deposits can be mitigated by post‐depositional processes. Here, we examine a peritidal phosphorite within a microbialite reef complex in the 2.4–2.2 Ga Turee Creek Group in Western Australia to assess the environmental information retained. Field mapping and petrography distinguishes between authigenic and locally transported phosphorite fragments, each of which contains unique information regarding the deposit. Elemental mapping and laser‐ablation analyses differentiate the impact of depositional versus early diagenetic versus metamorphic processes within these fragments. Samples within a near‐shore pebble conglomerate have mixed riverine‐oceanic signals and lack cerium anomalies, consistent with the depositional environment. Clasts from off‐shore peloidal grainstone beds retain “hat‐shaped” patterns with small negative cerium anomalies, reflective of transport and redeposition within potentially oxic seawater. U‐Pb isotopic dates range from ∼1.8 to 2.3 Ga and are generally uncorrelated with rare earth element and yttrium data. The youngest date (∼1.8 Ga) is associated with recrystallized apatite, with concave down, middle rare earth element enriched patterns. A potential depositional age, ∼2.3 Ga, is associated with massive apatite in a chert‐rich clast that has rare earth element patterns reflective of riverine‐oceanic signals. Overall, the peritidal system in the reef was dynamic, with potentially oxic seawater that had a strong riverine influence. Local recycling and reworking, early diagenesis, and later orogenic events impacted the preserved geochemical signals and together show that spatially resolved geochronological and geochemical data are ideal for interpreting ancient phosphorites.
Preservation of Hydrothermal Fluid Copper Isotope Signatures in Chalcopyrite‐Rich Chimneys: A Case Study From the PACMANUS Vent Field, Manus Basin
Authors: Samin Apolline , Roerdink Desiree L. , Reeves Eoghan P. , Scheffler Johannes , Bach Wolfgang , Beinlich Andreas , Jamieson John W. , Rouxel Olivier
Published: February 2024

Copper isotopes (δ65Cu) in hydrothermal fluids have the potential to provide information on ore‐forming processes occurring below the seafloor, but Cu isotope data from high‐temperature fluids are scarce. Here, we examine the extent to which coexisting sulfide minerals in a hydrothermal chimney can preserve fluid Cu isotope ratios using a fluid‐solid pair of a black smoker (333°C) from the Roman Ruins vent area (PACMANUS) in the Manus Basin. Two ca. 3 cm long transects through the chalcopyrite‐rich chimney wall show an increase in δ65Cu from 0.48 to 2.28‰ from the interior to the exterior, coupled with limited variation in sulfide δ34S (1.52–4.72‰). The Cu isotopic composition of chalcopyrite from the innermost wall closely resembles the δ65Cu value of the paired hydrothermal fluid, indicating that chalcopyrite in the inner ∼5 mm of the chimney records the Cu isotope ratio of the venting fluid. Beyond this, an increase in sulfide δ65Cu toward the exterior correlates with an increase in the relative abundance of secondary Cu sulfides. The appearance of bornite coincides with the presence of small barite crystals, suggesting this represents a redox gradient between reduced hydrothermal fluids and oxidized seawater admixing inwards. Elevated δ65Cu in this zone can be explained by the precipitation of secondary Cu sulfides from 65Cu‐enriched fluids formed during oxidative chalcopyrite dissolution. Our findings indicate that interactions with oxidizing seawater shift chalcopyrite δ65Cu values over small spatial scales, and that caution must be applied if chimney sulfides are used to reconstruct δ65Cu values of high‐temperature hydrothermal fluids.