Astronomical Research Research Articles

Data processing pipeline for Tianlai experiment

The Tianlai project is a 21cm intensity mapping experiment aimed at detecting dark energy by measuring the baryon acoustic oscillation (BAO) features in the large scale structure power spectrum. This experiment provides an opportunity to test the data processing methods for cosmological 21cm signal extraction, which is still a great challenge in current radio astronomy research. The 21cm signal is much weaker than the foregrounds and easily affected by the imperfections in the instrumental responses. Furthermore, processing the large volumes of interferometer data poses a practical challenge. We have developed a data processing pipeline software called {\tt tlpipe} to process the drift scan survey data from the Tianlai experiment. It performs offline data processing tasks such as radio frequency interference (RFI) flagging, array calibration, binning, and map-making, etc. It also includes utility functions needed for the data analysis, such as data selection, transformation, visualization and others. A number of new algorithms are implemented, for example the eigenvector decomposition method for array calibration and the Tikhonov regularization for $m$-mode analysis. In this paper we describe the design and implementation of the {\tt tlpipe} and illustrate its functions with some analysis of real data. Finally, we outline directions for future development of this publicly code.

Research of binary neutron star merger phenomenon by high speed sweeping observation

The pursuit of astronomical research has vastly expanded and illuminated our understanding of physics and the laws of the universe. This, in turn, is knowledge useful to a wide range of applications, many that would not have been foreseen in the original research. Astronomy helped create accurate navigation and mapping whilst technologies developed in the pursuit of the stars can be found in many key, everyday devices. Despite millennia of combing the night skies, there are still many mysteries about the universe that we do not yet understand. Professor Toshikazu Shigeyama and Associate Professor Shigeyuki Sako based at the Research Center for the Early Universe (RESCEU) and Institute of Astronomy (IoA), The University of Tokyo, Japan, are two astronomers working to uncover new information about our universe. They have led a team of researchers who were responsible for creating a new astronomical camera, the Tomo-e Gozen. This device will be capable of helping to shed light on several unknowns through the use of sensors able to capture images much closer together in time than ever before.

The AMADEE-18 Mars Analog Expedition in the Dhofar Region of Oman.

From February 1 to 28, 2018, the Austrian Space Forum, in cooperation with the Oman Astronomical Society and research teams from 25 nations, conducted the AMADEE-18 mission, a human-robotic Mars expedition simulation in the Dhofar region in the Sultanate of Oman. A carefully selected field crew, supported by a Mission Support Center in Innsbruck, Austria, conducted 19 experiments relevant to astrobiology, engineering disciplines, geoscience, operations research, and human factors. This expedition was the 12th in a series of analog missions that emulate selected aspects of the science expected for a human Mars mission, including the characterization of the (paleo)geological environment, human factors studies, and the search for biomarkers. In particular, an Exploration Cascade was deployed as a suggested workflow for coordinating the timing and location of the respective instruments and experiments. In validation of this workflow, the decision-making interaction between the field and the Mission Support Center was studied. This article introduces the AMADEE-18 mission and provides the mission-specific context for the other contributions of this special issue.

Author Correction: Expanding astronomy research in Malaysia

Author Correction: Expanding astronomy research in Malaysia

Raymond H. Wilson, Jr. (1911–1989)

Trained as an astronomer, Raymond H. Wilson, Jr., applied astronomical research methodologies to drive the innovations to move humankind into space. His career spanned over 50 years, from double-star observations to supervising applied mathematics research for NASA.

Expanding astronomy research in Malaysia

Astronomy research in Malaysia has progressed rapidly in the last few decades, with an increasing number of enthusiastic Malaysian astronomers working together to build new research groups and observing facilities, while establishing research networks both locally and globally.

Preface: Frontiers in Astrophysics (II) — A special issue dedicated to the 20th anniversary of RAA (2001–2020)

On the arrival of the 20th anniversary of the journal, Research in Astronomy and Astrophysics (RAA), we see rapid progress in the frontiers of astronomy and astrophysics. To celebrate the birth and growth of RAA, a special issue consisting of 11 invited reviews from more than 30 authors, mainly from China, has been organized. This is the second volume of the special issues entitled Frontiers in Astrophysics published in RAA. The publication aims at evaluating the current status and key progress in some frontier areas of astronomy and astrophysics with a spirit of guiding future studies.

Morphological classification of galaxies using Conv-nets

Since the beginning of space exploration, the galaxy classification has been a vexing problem that has always muddled the astrophysicists. A number of techniques have proven their remarkable utility in the classification of galaxies, however, upon analysis, these methods revealed certain inefficiencies that cannot be overlooked. The traditional classification of galaxies in the universe contains a significant part of their history in the authority of government agencies where the classifications in the previous years were performed primarily by experts manually. Today’s astronomical research produces large amounts of data and manually labelling the galaxy images based on morphological features can be time-consuming and error-prone. The objective of this paper is to study and analyze the different types of machine learning methodologies used for classifying galaxies. An inference drawn from this study is that using deep learning algorithms in conjunction with some data augmentation techniques provide excellent classification results of galaxies. Considering the aforementioned fact, the authors have proposed a layered CNN based classification model along with certain data augmentation techniques to classify galaxies morphological. “The Galaxy Zoo” dataset has been used from Kaggle which is further handcrafted for ease of classification. The galaxies are classified into three classes: spiral, elliptical, and lenticular (somewhere in-between). It has been observed from the experimental work that the proposed model outperform than its earlier contemporaries and can be used effectively to classify the galaxies.

Comparison of Astronomy school education curricula between Philippines and Japan

As a case study for developing countries aiming at improving science and Astronomy school education, we compare the Philippine and Japanese school science curricula. The Philippines recently changed its national curriculum with a view of strengthening science education. Japan, on the other hand, already has a reputable national curriculum and continues to be one of the outstanding countries in science education. Likewise, higher education and informal Astronomy education of the two countries were reviewed for similarities and differences. The Philippine and Japanese National Curriculum Standards and government approved science books were used in the analysis of their respective Astronomy learning competencies. The findings show that the Astronomy-related topics in both countries are almost the same, but Filipino students have more time and exposure to Astronomy concepts compared to Japanese students. On the other hand, Japan is rich in student research presentation in high school. Japan offers more opportunities and facilities to students who would like to pursue both Astronomy education and research. It seems that these backgrounds are the basis for richer Astronomy research environment in Japan.

Enabling discoveries: a review of 30 years of advanced technologies and instrumentation at the National Science Foundation

Over its more than 30-year history, the Advanced Technologies and Instrumentation (ATI) program has provided grants to support technology development and instrumentation for ground-based astronomy. Through a combination of automated literature assessment and in-depth literature review, we present a survey of ATI-funded research and its impact on astronomy and society. Award acknowledgment and literature citation statistics for ATI are comparable to a comparison astronomy grant program that does not support technology development. Citation statistics for both NSF-funded programs exceed those of the general astronomical literature. Numerous examples demonstrate the significant, long-term impact of ATI-supported research in astronomy. As part of this impact, ATI grants have provided many early career researchers the opportunity to gain critical professional experience. However, technology development unfolds over a time period that is longer than an individual grant. A longitudinal perspective shows that investments in technology and instrumentation have led to extraordinary scientific progress.

The Colour of the Night Sky.

The measurement of night sky quality has become an important task in night sky conservation. Modern measurement techniques involve mainly a calibrated digital camera or a spectroradiometer. However, panchromatic devices are still prevalent to this day, even in the absence of determining the spectral information of the night sky. In the case of multispectral measurements, colour information is currently presented in multiple ways. One of the most frequently used metrics is correlated colour temperature (CCT), which is not without its limitation for the purpose of describing especially the colour of natural night sky. Moreover, visually displaying the colour of the night sky in a quantitatively meaningful way has not attracted sufficient attention in the community of astronomy and light pollution research—most photographs of the night sky are post-processed in a way for aesthetic attractiveness rather than accurate representation of the night sky. The spectrum of the natural night sky varies in a wide range depending on solar activity and atmospheric properties. The most noticeable variation in the visible range is the variation of the atomic emission lines, primarily the green oxygen and orange sodium emission. Based on the accepted models of night sky emission, we created a random spectral database which represents the possible range of night sky radiance distribution. We used this spectral database as a learning set, to create a colour transformation between different colour spaces. The spectral sensitivity of some digital cameras is also used to determine an optimal transformation matrix from camera defined coordinates to real colours. The theoretical predictions were extended with actual spectral measurements in order to test the models and check the local constituents of night sky radiance. Here, we present an extended modelling of night sky colour and recommendations of its consistent measurement, as well as methods of visualising the colour of night sky in a consistent way, namely using the false colour enhancement.

An actuator nano and micro displacements for composite telescope in astronomy and physics research

We obtained the deformation, the structural diagram, the transfer functions and the characteristics of the actuator nano and micro displacements for composite telescope in astronomy and physics research. The mechanical and regulation characteristics of the actuator are received.

Data Lab—A community science platform

Abstract Data Lab is an open-access science platform developed and operated by the Community and Science Data Center (CSDC) at NSF’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab). It serves public photometric survey datasets, provides interactive and programmatic data access, and SQL/ADQL query capabilities via TAP. Users also receive generous storage allocations with VOSpace and MyDB, co-located with our data holdings. A host of services such as cross-matching, image cutouts via SIA, file services for survey data, and a Jupyter notebook interface for analysis close to the data complement the mission statement. Launched in 2017 at the National Optical Astronomy Observatory, Data Lab supports a base of over 1,300 registered users, processes on average 15,000 queries daily, serves over 50 TB of photometric catalogs, and provides access to over 2 PB of survey image products at NOIRLab’s Science Data Archive. Future development will include support for massive spectroscopic datasets and for processing of alert streams generated by e.g. ZTF and LSST. Users will also be able to create and administrate ad hoc user groups for shared data access and scientific analysis, and will enjoy containerized services and notebook spaces.

Impact of Satellite Constellations on Optical Astronomy and Recommendations Toward Mitigations

In May 2019 SpaceX launched its first batch of 60 Starlink communication satellites, which surprised astronomers and laypeople with their appearance in the night sky. Astronomers have only now, a little over a year later, accumulated enough observations of constellation satellites like those being launched by SpaceX and OneWeb, and run computer simulations of their likely impact when fully deployed, to thoroughly understand the magnitude and complexity of the problem. This research informed the discussion at the Satellite Constellations 1 (SATCON1) workshop held virtually 29 June to 2 July 2020 and led to recommendations for observatories and constellation operators. The SATCON1 report concludes that the effects on astronomical research and on the human experience of the night sky range from “negligible” to “extreme.”

High Efficiency Direct-drive Mount for Space Surveillance and NEO Applications

The design, manufacturing and field tests of a new astronomical telescope mount are the main topics of this paper. The new robotic mount dedicated for 0.5 m class telescopes is the first mount developed, developed and produced as fully Polish concept by engineers and researchers representing the automation and robotics discipline (Poznań University of Technology) and astronomy (Nicolaus Copernicus Astronomical Centre of the Polish Academy of Sciences). The mount is an alt-azimuth fork-type design which allows tracking of typical astronomical targets (sidereal tracking) but also man made objects (satellite tracking). Thanks to a unique mechanical design based on direct drive motors and high precision encoders coupled with custom electronics and on-board software implementing modern control theory achievements it was possible to obtain very good trajectory tracking precision throughout the entire dynamic range defined by the user scenarios. Additionally, the used control algorithms are robust to some class of disturbances such as friction which in turn allows for very high precision tracking in a wide range of angular velocities—from quasi-static movements to high-velocity satellite tracking. The test-bed infrastructure of the system is located in a dedicated astronomical research laboratory at the Poznań University of Technology campus. Local, remote as well as automatic observations can be carried out in the facility.

The decline of astronomical research in Venezuela

During the last 15 years the number of astronomy-related papers published by scientists in Venezuela has been continuously decreasing, mainly due to emigration. If rapid corrective actions are not implemented, Venezuelan astronomy could disappear.

Development of a 0.25 m f/10 reflecting telescope consisting of a thin primary mirror and a friction drive

Modern astronomical telescopes are comprised of high-quality optics and superior mounting designs to meet the standards and challenges of observational astronomy. Cost of commercial telescopes is a constraint for developing countries like Sri Lanka to be involved in astronomical related research. The objective of this research was to study the technological methods used in fabricating telescopes and to implement those methods to make economical telescopes locally. Therefore, a f/10 focal ratio Newtonian telescope consisting of a computerized friction drive alt-azimuth mount was fabricated with a locally ground thin telescope primary mirror made from Soda-lime glass plate having 0.25 m diameter and 0.012 m thickness. Deformation characteristics, profile formation and optical performance of the telescope primary mirror were investigated using finite element analysis, Polarization and Ronchi pattern analyses, respectively. Resolution, slew rate, torque and slippage of the fabricated friction drive were studied using a Computer Aided Design (CAD) model and an empirical approach. It was found that the profile of the mirror is a perfect parabola. The mirror was supported by a mirror cell with eighteen floating points and resultant root mean square wave-front error of the mirror due to the supporting points is 3.735x10-7m. The friction drive with the computer controller can position the telescope to a given angle with accuracies of 0.421 degrees on altitude axis and 0.03 degrees on azimuth axis. The total cost of production of the prototype telescope is about US$ 750.00. It is shown that there is a significant cost reduction and increased optical and mechanical performances of the telescope due to using the thin mirror and the friction drive mount. In this paper, the system design and the performance evaluation of the mechanical positioning and optical quality of the telescope are presented. Keywords: Newtonian telescope, mirror grinding, telescope driving system, thin telescope mirror.

A redistribution tool for long-term archive of astronomical observation data

Astronomical observation data require long-term preservation, and the rapid accumulation of observation data makes it necessary to consider the cost of long-term archive storage. In addition to low-speed disk-based online storage, optical disk or tape-based offline storage can be used to save costs. However, for astronomical research that requires historical data (particularly time-domain astronomy), the performance and energy consumption of data-accessing techniques cause problems because the requested data (which are organized according to observation time) may be located across multiple storage devices. In this study, we design and develop a tool referred to as AstroLayout to redistribute the observation data using spatial aggregation. The core algorithm uses graph partitioning to generate an optimized data placement according to the original observation data statistics and the target storage system. For the given observation data, AstroLayout can copy the long-term archive in the target storage system in accordance with this placement. An efficiency evaluation shows that AstroLayout can reduce the number of devices activated when responding to data-access requests in time-domain astronomy research. In addition to improving the performance of data-accessing techniques, AstroLayout can also reduce the storage systems power consumption. For enhanced adaptability, it supports storage systems of any media, including optical disks, tapes, and hard disks.

JEDDAH PLANETARIUM CENTER

Science center is a landmark building where visitors will be exposed to scientific knowledge that helps people develop new skills, solve practical problems and make informed decisions both individually and collectively. This work presents the development of the Jeddah Planetarium Center in Jeddah, Saudi Arabia. For this work, three case studies related to planetarium centers were analysed. Based on the case study analysis, for the proposed planetarium center, the estimated gross area is 11785 m2 and the net area is 7905 m2. The center is comprised of several collective zones such as planetarium, show section, administration and service. In addition, three sites have been proposed for the development of the planetary centre. Therefore, a site evaluation analysis was carried out in order to select the most appropriate site. In addition, weighting factors (WF) were used for the site assessment analysis. Based on the results of the site evaluation analysis, site 1 was selected as the proposed development site as it attained the highest score of 62. The Jeddah Planetarium Center was designed with modern and unique structure. This center is expected to benefit the Saudi Arabian community and enhance its involvement in science and research in astronomy.

The CARMA–NRO Orion Survey: Protostellar Outflows, Energetics, and Filamentary Alignment

Abstract We identify 45 protostellar outflows in CO maps of the Orion A giant molecular cloud from the Combined Array for Research in Millimeter-wave Astronomy–Nobeyama Radio Observatory Orion survey. Our sample includes 11 newly detected outflows. We measure the mass and energetics of the outflows, including material at low velocities, by correcting for cloud contributions. The total momentum and kinetic energy injection rates of outflows are comparable to the turbulent dissipation rate of the cloud. We also compare the outflow position angles to the orientation of C18O filaments. We find that the full sample of outflows is consistent with being randomly oriented with respect to the filaments. A subsample of the most reliable measurements shows a moderately perpendicular outflow-filament alignment that may reflect accretion of mass across filaments and onto the protostellar cores.