Astrophysical Research Research Articles

Tentative detection of titanium oxide in the atmosphere of WASP-69 b with a 4m ground-based telescope

ABSTRACT Transiting planets provide unique opportunities for the atmospheric characterization of exoplanets as they can reveal composition and the temperature structures at the day–night terminator regions in planetary atmospheres, and help understand the atmospheric process and formation environments of exoplanets. Here, we present the optical transmission spectroscopic study of an inflated Saturn-mass planet WASP-69 b, obtained by the 4m ground-based telescope Southern Astrophysical Research Telescope (SOAR). We obtain spectroscopic transit light curves in 20 passbands from 502 to 890 nm, and fit them using Gaussian processes and an analytical transit model to obtain independent transit depths for each. The derived transmission spectrum of WASP-69 b shows a slope with absorption depth increasing towards blue wavelengths, indicating a Rayleigh scattering in the atmosphere consistent with previous works. The retrieval analysis yields a tentative detection of TiO absorption feature in the transmission spectrum. We present the first results from the SOAR telescope to characterize exoplanetary atmospheres proving its capability and precision for hot Jupiters around bright stars in an area dominated by results from large ground-based telescopes or space telescopes.

Case study of developing an affordable undergraduate observatory

Astronomy is one of the few sciences where the data (star-light) can be seen by all. Yet, there is a disconnect between a typical undergraduate lecture and, for example, where a planet may be in the sky and how to observe it. With the advent of moderate cost, high-quality ‘back-garden’ astronomy, and standard computers powerful enough to produce original research, we show it is possible to build a small observatory capable of actual astrophysical research for a modest budget £. We detail the iterative process of planning, funding, results and student-projects, that we followed over 4 years from a Raspberry Pi camera and home-owned telescope, to a permanent roll-top observatory with two fully automated telescope systems capable of undergraduate use and astronomical science. We report on projects ranging from early-years projects based on observational planning, data analysis and some restricted actual observations, to more open-ended final-year projects to observe, e.g. planetary transits, variable stars or high-resolution planetary imaging. We hope this work may act as a blue-print or encourage and aid other small to medium sized higher-education institutions and astrophysics groups to also develop their own undergraduate observatory.

Daily distribution of meteor flight frequency according to radio observations

The paper considers the problem of studying the daily distribution of the passage of meteoroids by radio observation. The advantages of the chosen method of registration over the classical optical and photographic methods of observation are considered. A voluminous series of data was obtained using a registration facility implemented on the basis of the Center for Astrophysical Research at the North Kazakhstan University named after Manash Kozybayev. Processing, analysis and systematization of the obtained data on meteor phenomena have been carried out. Based on the obtained observational data, on the basis of the Center for Astrophysical Research at the North Kazakhstan University named after Manash Kozybayev, using the Multi VirAnalyzer program, namely the Date Recorder, the daily distribution of the meteor flight frequency was calculated. Also, with the help of the Microsoft Excel software application, diagrams of the daily distribution of the meteor passage frequency were constructed. During the analysis of the obtained diagrams of the daily distribution of the meteor passage frequency, the peak and average daily values of meteor activity were determined. Based on the daily distribution, diagrams of the frequency of meteor passages were constructed for certain months during which the Perseid and Leonid meteor showers are active. A clear correlation with the results of studies of other laboratories of a similar line of research is shown.

Yong Seol Kim

Yong Seol Kim, 51, died March 13, 2022, in Honolulu. “Yong Seol was a brilliant chemist who never stopped looking to improve our community. He received a fellowship with a European Commission-funded Marie Curie Research Training Network called Quantitative Spectroscopy for Atmospheric and Astrophysical Research at the University of Wuppertal in Germany (2006–2007). Yong Seol then joined the Physical Chemistry (2008–2014) and Astrochemistry (2008–2012) Departments at the University of Hawaii where he researched small molecule synthesis and spectroscopic characterization. His final work at Hawaii’s State Laboratories Division was to modify standard operating procedures for determining phosphorus levels in nonpotable water samples using UV digestion.”—Soo Yeon Lee, wife Most recent title: Chemist, State Laboratories Division, Hawaii Education: BS, chemistry, Dongguk University, 1996; MS, physical organic chemistry, Illinois State University, 2000; PhD, organic chemistry, University of Wisconsin–Madison, 2005 Survivors: Parents, Seung Suk and Phil Soo; wife, Soo Yeon Lee; children, Silvia and

Creation and direct laser acceleration of positrons in a single stage

Relativistic positron beams are required for fundamental research in nonlinear strong field QED, plasma physics, and laboratory astrophysics. Positrons are difficult to create and manipulate due to their short lifetime, and their energy gain is limited by the accelerator size in conventional facilities. Alternative compact accelerator concepts in plasmas are becoming more and more mature for electrons, but positron generation and acceleration remain an outstanding challenge. Here, we propose a new setup where we can generate, inject, and accelerate them in a single stage during the propagation of an intense laser in a plasma channel. The positrons are created from a laser-electron collision at 90\ifmmode^\circ\else\textdegree\fi{}, where the injection and guiding are made possible by an 800-nC electron beam loading which reverses the sign of the background electrostatic field. We obtain a 17-fC positron beam, with GeV-level central energy within 0.5 mm of plasma.

Recovery of no-carrier-added 41Ca, 44Ti, and 26Al from high-energy proton-irradiated vanadium targets

Abstract Many useful and needed radionuclides for medicinal, astrophysical, and environmental research are produced naturally in inefficient quantities or not-at-all. In the method described here, rare cosmogenic isotopes were produced via spallation reactions in metallic vanadium and separated without adding any carriers. In the SINQ facility at the Paul Scherrer Institut, the vanadium targets were irradiated for two years with high-energy protons (≤590 MeV). After a cooling period of eight years, only relatively long-lived radionuclides such as 32Si, 44Ti, 41Ca, and 26Al remain present. After target dissolution, 32Si was first separated for a prospective half-life redetermination. The remaining 32Si-free solution was used for extracting 44Ti, 41Ca, and 26Al, three key isotopes which are scientifically interesting for nuclear astrophysics research as well as medical applications. Each separation scheme employed ion-exchange and extraction chromatography; developed and optimized using inactive model solutions analyzed with Inductively Coupled Plasma–Optical Emission Spectrometry (ICP–OES). The irradiated samples were tracked with γ-ray spectroscopy for γ-ray emitting impurities. As a result, radiochemically pure sample solutions of 44Ti, 41Ca, and 26Al were obtained as “ready for use” in different application fields.

Characterization of relativistic electron–positron beams produced with laser-accelerated GeV electrons

The characterization of an electron–positron beam generated from the interaction of a multi-GeV electron beam with a lead plate is performed using GEANT4 simulations. The dependence of the positron beam size on driver electron beam energy and lead converter thickness is investigated in detail. A pancake-like positron beam structure is generated with a monoenergetic multi-GeV driver electron beam, with the results indicating that a 5 GeV driver electron beam with 1 nC charge can generate a positron beam with a density of 1015–1016 cm−3 at one radiation length of lead. In addition, we find that electron–positron beams generated using above-GeV electron beams have neutralities greater than 0.3 at one radiation length of lead, whereas neutralities of 0.2 are observed when using a 200 MeV electron beam. The possibility of observing plasma instabilities in experiments is also examined by comparing the plasma skin depth with the electron–positron beam size. A quasi-neutral electron–positron plasma can be produced in the interaction between a 1 nC, 5 GeV electron beam and lead with a thickness of five radiation lengths. Our findings will aid in analyzing and interpreting laser-produced electron–positron plasma for laboratory astrophysics research.

EFFECT OF GAMMA IRRADIATION ON ELECTRICAL AND PHOTOELECTRICAL PROPERTIES OF Cd1-xMnxTe THIN FILMS

AIIB VI groups of compound semiconductors, their solid solutions, bulk and thin films on their base have wide application possibilities in modern microelectronics. Creation of photosensitive elements and structures on the base of these semiconductors and investigations of their usage potentials in various fields of optoelectronics is one of the most actual problems of modern materials science and engineering. Recently, AII(TM= Mn, Fe, Co, etc)BVI based semimagnetic semiconductors (SMSC) compounds has attracted increasing interest since they considered a promising material for the fabrication of high-performance roomtemperature γ- and x-ray detectors. Such detectors offer great potential for nonproliferation applications, medical imaging, astrophysics research, and monitoring industrial processes, because they are able to operate at ambient temperatures, while providing a high detection efficiency and good energy resolution. The aim of the work is to determine of photosensitivity range of Cd1-xMnxTe SMSC thin films, to investigate their sensitivity to γ- irradiation and to study the creation possibility of γ- ray detectors on the base these thin films. In these respect, VAC and photoconductivity, as well as effect of γ- ray irradiation on these properties has been studied. Results of current investigation reveal that, Cd1-xMnxTe (x=0.07) epitaxial films of compounds are sensitive to γ-ray irradiation, indicating that these materials can be considered as a good candidate for γ-ray detector applications.

Locating sources of a high energy cosmic ray extensive air shower using HiSPARC data

In the physics community, there is continued interest in high energy cosmic rays and their co-location to stellar sources, including to supernovae. Observational history and corresponding theories link the high energies associated with these types of cosmic rays to those produced in various latter evolution stages of stellar bodies. We hypothesize that high-energy cosmic ray air showers have a source region associated with specific stellar bodies. Here, we present our analysis of the locations of possible high-energy cosmic ray sources by using data from University of Twente cosmic ray detectors that are part of the High School Project on Astrophysics Research with Cosmics (HiSPARC) network. As an example of the potential of the HiSPARC network to aid cosmic ray source location, we analyzed event count data from a high-energy air shower recorded during the first week of January 2014. The data was then processed such that the direction of the air shower could be ascertained to provide the likely area of air shower origin. Angle and time data were then inputted in to Stellarium™, a free open-source planetarium application from which sources could be located. Our results suggest two sources are candidates for the origins of the high-energy air shower: the Cepheid variable Polaris and the binary system, Iota Ursae Majoris A. In sum, we have shown the potential of the HiSPARC network to aid location of stellar sources that may be responsible for detected cosmic air showers.

Background gamma measurement for low energy astrophysical reaction at FRENA

The majority of astrophysical reactions have very low cross-sections (nanobarn to picobarn range) and significant error bars [1, 2]. Hence γ-ray background studies up to 3 MeV have been performed inside the Facility for Research in Experimental Nuclear Astrophysics (FRENA), Saha Institute of Nuclear Physics, Kolkata, India. A meticulous background calculation has been performed at different positions inside the accelerator hall and beam hall using two NaI(Tl) detectors [3]. An XPS measurement has been carried out to identify elements present in the FRENA wall concrete. Activity calculations done in [4] shows that neutrons produced by various experiments may combine with any nearby elements and form various radioactive isotopes with long half-lives, which may produce a γ-ray background .

Study for the long-lived gamma background due to neutron emitting calibration reactions

In this article, a detailed theoretical investigation has been done on the long-lived gamma background due to neutron emitting reactions. It mainly focused on the experiments that will be used to calibrate energy with the terminal voltage of an upcoming Facility for Research in Experimental Nuclear Astrophysics (FRENA). Many reactions like (p, n), (p, γ) have been utilized in various accelerator facilities around the globe for energy calibration purposes. Neutron emitting reactions like 7Li(p, n), 13C(p, n), 19F(p, n), 27Al(p, n), etc. have been very commonly used. For such reactions, a significant number of neutrons produced from such experiments can interact with surrounding elements like copper, tantalum, stainless steel (SS304 and SS316), concrete materials,etc. These interactions may create long-lived gamma activity in the vicinity of the accelerator and detection area. Background gammas from these radioactive isotopes can interfere with gamma measurements in future experiments. The present study has been done to investigate those possibilities of gamma background which may occur due to the calibration study by neutron emitting experiments. Here 7Li(p, n), 13C(p, n), 19F(p, n) and 27Al(p, n) reactions having neutron threshold energies 1.8803, 3.2355, 4.2351, 5.8036 MeV respectively are chosen keeping in mind the proton energy available at the facility.

Optimal Observational Scheduling Framework for Binary and Multiple Stellar Systems* *Based in part on observations obtained at the international Gemini Observatory, a program of NSF's NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation on behalf of the Gemini Observatory partnership: the National Science Foundation (United

The optimal instant of observation of astrophysical phenomena for objects that vary on human timescales is an important problem, as it bears on the cost-effective use of usually scarce observational facilities. In this paper, we address this problem in the case of tight visual binary systems through a Bayesian framework based on the maximum entropy sampling principle. Our proposed information-driven methodology exploits the periodic structure of binary systems to provide a computationally efficient estimation of the probability distribution of the optimal observation time. We show the optimality of the proposed sampling methodology in the Bayes sense and its effectiveness through direct numerical experiments. We successfully apply our scheme to the study of two visual-spectroscopic binaries and one purely astrometric triple hierarchical system. We note that our methodology can be applied to any time-evolving phenomena, a particularly interesting application in the era of dedicated surveys, where a definition of the cadence of observations can have a crucial impact on achieving the science goals.

Univocal Discrimination of α Particles Produced by 11B(p, α)2α Fusions in Laser-Matter Experiments by Advanced Thomson Spectrometry

The energy problem is an open issue becoming increasingly pressing. The possibility to use nuclear fusion as an alternative energy source is thus acquiring progressively more importance and many investors are pushing to achieve the goal of an electric plant based on fusion. The most studied reaction is the deuterium-tritium one, but this poses several technical issues related to the handling of the radioactive fuel and neutron generation. In this frame, the aneutronic 11B(p, α)2α fusion reaction has attracted the interest of many researchers. Despite a fusion reactor based on pB is still a long-term goal, the study of this reaction is important both for astrophysics research and for its possible employment in schemes of high brightness source of α particles for applications, as for instance in medicine. Nevertheless, the univocal identification of the produced alphas is a well-known challenging task when the reaction is triggered by high-intensity lasers. Indeed, due to the multifaceted emission typical of laser-matter interactions, the signal coming from alphas is often superimposed to that generated by protons and by other ions, and in many cases, it is therefore hardly recognizable. In this work, we analysed the possibility of employing a Thomson spectrometer (TS) with an adequate differential filtering system for the exclusion from the α-particle trace, the contribution of all other ionic species. Moreover, for the energy ranges where the filtering method cannot be successfully applied, we investigated the feasibility of integrating in the TS assembly a particle detector for time-of-flight (TOF) measurements.

The preparation of isotopic boron targets – searching for a more consistent approach

The reliable availability of isotopic boron targets has gained in importance concerning light ion reactions withing the realm of nuclear astrophysics research and remain somewhat elusive. An exhaustive approach was undertaken via electron beam evaporation to produce self-supporting and backed targets spanning quite a few isotopic samples across several suppliers, resulting only in limited success. Details of the extensive sample preparation procedures undertaken, and the experimental deposition techniques explored will be presented.

Partnerships in Astronomy and Astrophysics Research and Education (NSF)

Federal Grants & ContractsVolume 47, Issue 1 p. 2-2 Grants Alerts Partnerships in Astronomy and Astrophysics Research and Education (NSF) First published: 25 November 2022 https://doi.org/10.1002/fgc.32717Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume47, Issue11 December 2022Pages 2-2 RelatedInformation

Gaia white dwarfs within 40 pc – III. Spectroscopic observations of new candidates in the Southern hemisphere

Abstract We present a spectroscopic survey of 248 white dwarf candidates within 40 pc of the Sun; of these 244 are in the Southern hemisphere. Observations were performed mostly with the Very Large Telescope (X-Shooter) and Southern Astrophysical Research Telescope. Almost all candidates were selected from Gaia Data Release 3 (DR3). We find a total of 246 confirmed white dwarfs, 209 of which had no previously published spectra, and two main-sequence star contaminants. Of these, 100 white dwarfs display hydrogen Balmer lines, 69 have featureless spectra, and two show only neutral helium lines. Additionally, 14 white dwarfs display traces of carbon, while 37 have traces of other elements that are heavier than helium. We observe 35 magnetic white dwarfs through the detection of Zeeman splitting of their hydrogen Balmer or metal spectral lines. High spectroscopic completeness (> 97 per cent) has now been reached, such that we have 1058 confirmed Gaia DR3 white dwarfs out of 1083 candidates within 40 pc of the Sun at all declinations.

Samuil Kaplan and the development of astrophysical research at the Lviv University

Samuil Kaplan and the development of astrophysical research at the Lviv University

Risk Assessment of Environmental Conditions Affecting the Useful Lifetime of Cherenkov Telescopes at El Roque de Los Muchachos Observatory

Construction and operation of ground astrophysical facilities can be affected by adverse weather conditions. Some weather risks are obvious, but still there are times when an unforeseen event distorts the perception of how relevant a climate-related risk is. On the other hand, adverse weather conditions can delay or entirely halt the construction project of an astronomical facility. The impact of weather risks becomes stronger if the facility is built at a site far from urban areas, where maintenance activities and hardware availability become more challenging. This paper aims at proposing a procedure to analyze the impact of environmental risks for an astronomical facility. This procedure is illustrated with a case study: El Roque de Los Muchachos Observatory (ORM). ORM hosts a number of large scale instruments for astrophysics research, which will significantly increase during this decade. We analyze in this paper the environmental conditions affecting the useful lifetime of Cherenkov Telescopes installed at the ORM. After a detailed analysis, we conclude that the risks of strongest magnitude are connected to wild fires. This conclusion diverges from the current risk perception, which is strongly influenced by the recent Cumbre Vieja Eruption event.

The strongest cool core in REXCESS: Missing X-ray cavities in RXC J2014.8–2430

We present a broad, multi-wavelength study of RXC J2014.8−2430, the most extreme cool-core cluster in the Representative XMM-Newton Cluster Structure Survey (REXCESS), using Chandra X-ray, Southern Astrophysical Research (SOAR) Telescope spectroscopic and narrow-band imaging, Atacama Large Millimeter/submillimeter Array (ALMA), Very Large Array, and Giant Metrewave Radio Telescope observations. While feedback from an active galactic nucleus (AGN) is thought to be the dominant mechanism by which a cooling flow is suppressed, the Chandra imaging observations surprisingly do not reveal the bi-lateral X-ray cavities one might expect to see in the intracluster medium (ICM) of an extreme cool core hosting a powerful radio source, though cavities commonly appear in many similar sources. We discuss the limits on the properties of putative radio bubbles associated with any undetected X-ray cavities. We place upper limits on any significant X-ray AGN in the brightest cluster galaxy (BCG) and show that the X-ray peak is offset from the central radio source, which exhibits a steep low-frequency radio spectrum indicative of electron ageing. The imaging and spectroscopy provided by SOAR reveal an extended, luminous optical emission-line source. From our narrow-band Hα imaging of the BCG, the central Hα peak is coincident with the radio observations, yet offset from the X-ray peak, consistent with sloshing found previously in this cluster. ALMA observations of the CO(1−0) emission reveal a large reservoir of molecular gas that traces the extended Hα emission in the direction of the cool core. We conclude either that the radio source and its cavities in the X-ray gas are nearly aligned along the line of sight, or that ram pressure induced by sloshing has significantly displaced the cool molecular gas feeding it, perhaps preempting the AGN feedback cycle. We argue that the sloshing near the core is likely subsonic, as expected, given the co-location of the Hα, CO(1−0), radio continuum, and stellar emission peaks and their proximity to the X-ray peak. Further, the X-ray emission from the core is strongly concentrated, as is the distribution of metals, indicating the cool core remains largely intact. Deeper Chandra observations will be crucial for definitively establishing the presence or lack of X-ray cavities, while X-ray micro-calorimetric observations from Athena could establish if the motion of the cold and warm gas is dominated by large-scale motions of the surrounding ICM.

Absorption caused by potassium molecules in astrophysical plasmas: Data needed for modeling

In this study, the processes of photo-dissociation in the cases of symmetric and strongly non-symmetric systems which involve hydrogen and potassium are investigated. The aim of this study was to calculate data for those small molecules and molecular state characterizations as well as to obtain the corresponding partial and average cross-sections. Moreover, the corresponding spectral absorption rate coefficients for symmetric and strongly non-symmetric cases i.e. for K2+ and KH+ cases are given in tables as a function of temperatures and wavelengths allowing potential modeling. The current research and presented results can be of interest for astrophysical plasma research and laboratory plasma investigation.