A5050600542- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Spectroscopy and Chemometric Analyses
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Calibration and Measurement Techniques
- Inertial Sensor and Navigation
- Galaxies: Formation, Evolution, Phenomena
- Gender Diversity and Inequality
- Spectroscopy Techniques in Biomedical and Chemical Research
- Medical Imaging Techniques and Applications
- Evacuation and Crowd Dynamics
- Public-Private Partnership Projects
- Data Visualization and Analytics
- Advanced Electrical Measurement Techniques
- Advanced Image Fusion Techniques
- Fire dynamics and safety research
- Electrical Fault Detection and Protection
Royal Observatory
2015-2024
University of Edinburgh
2015-2024
Liverpool John Moores University
2018-2023
University of Warsaw
2020-2023
Tel Aviv University
2021-2023
Western Carolina University
2022-2023
University of Virginia
2012-2019
Scottish Universities Physics Alliance
2017
We describe the design and performance of near-infrared (1.51--1.70 micron), fiber-fed, multi-object (300 fibers), high resolution (R = lambda/delta lambda ~ 22,500) spectrograph built for Apache Point Observatory Galactic Evolution Experiment (APOGEE). APOGEE is a survey 10^5 red giant stars that systematically sampled all Milky Way populations (bulge, disk, halo) to study Galaxy's chemical kinematical history. It was part Sloan Digital Sky Survey III (SDSS-III) from 2011 -- 2014 using 2.5...
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) uses a dedicated 300-fiber, narrow-band near-infrared (1.51-1.7 μm), high resolution (R~22,500) spectrograph to survey approximately 100,000 giant stars across the Milky Way. This three-year survey, in operation since late-summer 2011 as part of Sloan Digital Sky Survey III (SDSS III), will revolutionize our understanding kinematical and chemical enrichment histories all stellar populations. We present performance instrument...
Stellar-mass black holes descend from high-mass stars, most of which had stellar binary companions. However, the number those systems that survive evolution and hole formation is uncertain by multiple orders magnitude. The survival rate particularly for massive stars with low-mass companions, are thought to be progenitors X-ray binaries. We present a search close companions (orbital period lesssim 3,days, equivalent separation 20 R_⊙) AFGK-type in TESS ; is, non-accreting counterparts Such...
Abstract The optical-ultraviolet transient AT 2021loi is located at the center of its host galaxy. Its spectral features identify it as a member Bowen fluorescence flare (BFF) class. first this class was considered to be related tidal disruption event, but enhanced accretion onto an already active supermassive black hole suggested alternative explanation. Having occurred in previously known unobscured galactic nucleus, strengthens latter interpretation. light curve similar those previous...
Abstract AT 2019azh is a H+He tidal disruption event (TDE) with one of the most extensive ultraviolet and optical data sets available to date. We present our photometric spectroscopic observations this starting several weeks before out approximately 2 yr after g -band's peak brightness combine them public data. This set robustly reveals change in light-curve slope possible bump rising light curve TDE for first time, which may indicate more than dominant emission mechanism contributing...
Blue Large Amplitude Pulsators (BLAPs) are hot, subluminous stars undergoing rapid variability with periods of under 60 mins. They have been linked the early stages pre-white dwarfs and hot subdwarfs. a rare class variable star due to their evolutionary history within interacting binary systems short timescales relative lifetime in which they pulsationally unstable. All currently known BLAPs relatively faint (15-19 mag) located Galactic plane. These intrinsically blue colours but large...
Abstract We provide a suite of public open-source spectral data-reduction software to rapidly obtain scientific products from all forms long-slit-like spectroscopic observations. Automated SpectroPhotometric REDuction ( ASPIRED ) is Python -based toolkit. It designed be general toolkit with high flexibility for users refine and optimize their routines the individual characteristics instruments. The default configuration suitable low-resolution long-slit spectrometers provides quick-look...
Context. Microlensing provides a unique opportunity to detect non-luminous objects. In the rare cases that Einstein radius θ E and microlensing parallax π can be measured, it is possible determine mass of lens. With technological advances in both ground- space-based observatories, astrometric interferometric measurements are becoming viable, which lead more routine determination and, if also Aims. We present photometric analysis Gaia19bld, high-magnification ( A ≈ 60) event located southern...
We analyze four extreme active galactic nuclei (AGN) transients to explore the possibility that they are caused by rare, high-amplitude microlensing events. These previously unknown type-I AGN located in redshift range 0.6-1.1 and show changes of > 1.5 mag g-band on a time-scale ~years. Multi-epoch optical spectroscopy, from William Herschel Telescope, shows clear differential variability broad line fluxes with respect continuum also evolution profiles. In two cases, simple point-source,...
A classical nova is an eruption on the surface of a white dwarf in accreting binary system. The material ejected from generally forms axisymmetric shell. shaping mechanisms shells are probes processes that take place at energy scales between planetary nebulae and supernova remnants. We report discovery surrounding post-nova systems V4362 Sagittarii (1994) more limited observations DO Aquilae (1925). Distance measurements 0.5p/m1.4 kpc for Sgr 6.7 p/m 3.5 -0.2 Aql found based expansion...
A large sample of white dwarfs is selected by both proper motion and colours from the Pan-STARRS 1 3{\pi} Steradian Survey Processing Version 2 to construct White Dwarf Luminosity Functions discs halo in solar neighbourhood. Four-parameter astrometric solutions were recomputed epoch data. The generalised maximum volume method then used calculate density populations. After removal crowded areas near Galactic plane centre, final sky area this work 7.833 sr, which 83% 62% whole sky. By dividing...
Ultra-cool white dwarfs are among the oldest stellar remnants in Universe. Their efficient gravitational settling and low effective temperatures responsible for smooth spectra they exhibit. For that reason, it is not possible to derive their radial velocities or find chemistry of progenitors. The best can be done infer such properties from associated sources, which coeval. simplest form a system common proper motion pair where one star an evolved degenerate other main-sequence star. In this...
The traditional Schmidt density estimator has been proven to be unbiased and effective in a magnitude-limited sample. Previously, efforts have made generalize it for populations with non-uniform proper motion-limited cases. This work shows that the then-good assumptions sample are no longer sufficient cope modern data. Populations larger differences kinematics as compared local standard of rest most severely affected. We show this systematic bias can removed by treating discovery fraction...
Blue Large-Amplitude Pulsators (BLAPs) are a new class of pulsating variable star. They located close to the hot subdwarf branch in Hertzsprung-Russell diagram and have spectral classes late O or early B. Stellar evolution models indicate that these stars likely radially pulsating, driven by iron group opacity their interiors. A number with similar driving mechanism exist near multi-periodic oscillations caused either pressure (p) gravity (g) modes. No signals were detected OGLE discovery...
Abstract From data collection to photometric fitting and analysis of white dwarfs, generating a dwarf luminosity function requires numerous astrophysical, mathematical, computational domain knowledge. The steep learning curve makes it difficult enter the field, often individuals have reinvent wheel perform identical reduction tasks. We gathered wide range publicly available cooling models synthetic photometry provide toolkit that allows (i) visualization various models, (ii) with or without...
Stellar-mass black holes descend from high-mass stars, most of which had stellar binary companions. However, the number those systems that survive evolution and hole formation is uncertain by multiple orders magnitude. The survival rate particularly for massive stars with low-mass companions, are thought to be progenitors X-ray binaries. We present a search close companions (separations less than 20 solar radii) AFGK-type in TESS, i.e. non-accreting counterparts Such can detected tidally...
We search the archival Zwicky Transient Facility public survey for rapidly evolving transient (RET) candidates based on well-defined criteria between 2018 May and 2021 December. The yielded 19 bona-fide RET candidates, corresponding to a discovery rate of $\sim 5.2$ events per year. Even with Galactic latitude cut $20^\circ$, 8 ($\sim 42$%) are Galactic, including one light-curve shape closely resembling that GW170817 kilonova (KN). An additional event is nova in M31. Four out 21$%)...
AT 2019azh is a H+He tidal disruption event (TDE) with one of the most extensive ultraviolet and optical data sets available to date. We present our photometric spectroscopic observations this starting several weeks before out approximately two years after g-band peak brightness combine them public data. This set robustly reveals change in light-curve slope possible bump rising light curve TDE for first time, which may indicate more than dominant emission mechanism contributing pre-peak...
The survey volume of a proper motion-limited sample is typically much smaller than magnitude-limited sample. This because the noisy astrometric measurements from detectors that are not dedicated for missions. In order to apply an empirical completeness correction, existing works limit depth shallower parts sky hamper maximum potential survey. number epoch measurement discrete quantity cannot be interpolated across projected plane observation, so properties change in steps sky. work proposes...
The Liverpool Telescope has been in fully autonomous operation since 2004. supporting data archive facility largely untouched. provision service not an issue although some modernisation of the system is desirable. This project timely. Not only does it suit upgrade current LT archive, line with design phase New Robotic which will be online early-2020s; and development a new for range telescopes at National Astronomical Research Institute Thailand. Newton Fund enabled us to collaborate...
Wavelength calibration is a routine and critical part of any spectral work-flow, but many astronomers still resort to matching detected peaks emission lines by hand. We present RASCAL (RANSAC Assisted Spectral CALibration), python library for automated wavelength astronomical spectrographs. implements recent state-of-the-art methods requires minimal input from user. In this paper we discuss the implementation apply it real-world spectra.
The development of professional sports stadiums in the United States typically relies on public funding form municipal bonds. Prior research has identified several economic and noneconomic reasons local governments choose to direct funds towards construction stadiums. overall conclusion this suggests sport do not result significant increases activity therefore subsidized stadium projects lack justification. In study, process issuing bonds is examined. authors describe bond issuance utilize...