A5075135982- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Space Exploration and Technology
- Veterinary Equine Medical Research
- Remote Sensing in Agriculture
- Geological and Geophysical Studies
- Geophysics and Gravity Measurements
- Bee Products Chemical Analysis
- PARP inhibition in cancer therapy
- Impact of Light on Environment and Health
- DNA Repair Mechanisms
- Geomagnetism and Paleomagnetism Studies
- Solar and Space Plasma Dynamics
- History and Developments in Astronomy
- Advanced Memory and Neural Computing
- Innovative Human-Technology Interaction
- Geology and Paleoclimatology Research
- Calibration and Measurement Techniques
- Crafts, Textile, and Design
Leibniz Institute for Astrophysics Potsdam
2017-2023
University of Exeter
2013-2019
University of Rochester
2014-2019
Campbell Collaboration
2019
American Industrial Partners (United States)
2017
ETH Zurich
2016
We present a self-consistent, absolute isochronal age scale for young (< 200 Myr), nearby 100 pc) moving groups in the solar neighbourhood based on homogeneous fitting of semi-empirical pre-main-sequence model isochrones using tau^2 maximum-likelihood statistic Naylor & Jeffries M_V, V-J colour-magnitude diagram. The final adopted ages are: 149+51-19 Myr AB Dor group, 24+/-3 {\beta} Pic group (BPMG), 45+11-7 Carina association, 42+6-4 Columba 11+/-3 {\eta} Cha cluster, 45+/-4...
Jeffries & Binks (2014) and Malo et al. have recently reported Li depletion boundary (LDB) ages for the {\beta} Pictoris moving group (BPMG) which are twice as old oft-cited kinematic age of $\sim$12 Myr. In this study we present (1) a new evaluation internal kinematics BPMG using revised Hipparcos astrometry best available published radial velocities, assess whether useful can be derived, (2) derive an isochronal based on placement A-, F- G-type stars in colour-magnitude diagram (CMD). We...
We have derived ages for 13 young (<30 Myr) star-forming regions and find that they are up to a factor of 2 older than the typically adopted in literature. This result has wide-ranging implications, including circumstellar discs survive longer (≃ 10–12 average Class I lifetime is greater (≃1 currently believed. For each region, we two from colour–magnitude diagrams. First, fitted models evolution between zero-age main sequence terminal-age derive homogeneous set main-sequence ages, distances...
We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for four-metre-class Visible and Infrared Survey Astronomy (VISTA) at Paranal. Its key specifications are: large field of view (FoV) 4.2 square degrees high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs ($R = λ/Δλ\sim 6500$), 812 transferring light to high-resolution spectrograph \sim 20\,000$). After...
Abstract The Large and Small Magellanic Clouds are unique local laboratories for studying the formation evolution of small galaxies in exquisite detail. Survey MAgellanic Stellar History (SMASH) is an NOAO community Dark Energy Camera (DECam) survey mapping 480 deg 2 (distributed over ∼2400 square degrees at ∼20% filling factor) to ∼24th mag ugriz . primary goals SMASH identify low surface brightness stellar populations associated with halos tidal debris Clouds, derive spatially resolved...
We present a critical assessment of commonly used pre-main-sequence isochrones by comparing their predictions to set well-calibrated colour–magnitude diagrams the Pleiades in wavelength range 0.4–m. Our analysis shows that for temperatures less than 4000 K, models systematically overestimate flux factor 2 at m, though this decreases with wavelength, becoming negligible m. In optical colours will result ages stars younger 10 Myr being underestimated factors between and 3.
WISE J080822.18$-$644357.3 was recently identified as a new M dwarf debris disc system and candidate member of the 45 Myr-old Carina association. Given that strength its infrared excess ($L_{\rm IR}/L_{\rm \star}\simeq 0.1$) appears to be more consistent with young protoplanetary disc, we present first optical spectra star reassess evolutionary membership status. We find J0808-6443 Li-rich M5 strong H$\alpha$ emission ($-125 < \textrm{EW} -65$ \AA\ over 4 epochs) whose broad width are...
The Magellanic Clouds are nearby dwarf irregular galaxies whose morphologies show different properties when traced by stellar populations, making them an important laboratory for studying galaxy morphologies. We study the morphology of using data from VISTA survey system (VMC). used about $10$ and $2.5$ million sources across area $\sim105$ deg$^2$ $\sim42$ towards Large Small Cloud (LMC SMC), respectively. estimated median ages populations occupying regions near-infrared ($J-K_\mathrm{s},...
We derive the spatially-resolved star formation history (SFH) for a $96$ deg$^2$ area across main body of Large Magellanic Cloud (LMC), using near-infrared photometry from VISTA survey Clouds (VMC). The data and analyses are characterised by great degree homogeneity low sensitivity to interstellar extinction. 756 subregions size $0.125$ -- corresponding projected sizes about $296\times322\,\mathrm{pc}^{2}$ in LMC analysed. resulting SFH maps, with typical resolution $0.2$--$0.3$ dex...
The Large and Small Magellanic Clouds (LMC SMC) are the largest satellite galaxies of Milky Way close enough to allow for a detailed exploration their structure formation history. Survey MAgellanic Stellar History (SMASH) is community Dark Energy Camera (DECam) survey using $\sim$50 nights sample over $\sim$2400 deg$^2$ centered on at $\sim$20% filling factor (but with contiguous coverage in central regions) depths $\sim$24th mag $ugriz$. primary goals SMASH map out extended stellar...
We present an isochrone server for semi-empirical pre-main-sequence model isochrones in the following systems: Johnson–Cousins, Sloan Digital Sky Survey, Two-Micron All-Sky Isaac Newton Telescope (INT) Wide-Field Camera and INT Photometric Hα Survey (IPHAS)/UV-Excess (UVEX). The can be accessed via Cluster Collaboration webpage http://www.astro.ex.ac.uk/people/timn/isochrones/. To achieve this, we have used observed colours of member stars young clusters with well-established age, distance...
ABSTRACT The periphery of the Small Magellanic Cloud (SMC) can unlock important information regarding galaxy formation and evolution in interacting systems. Here, we present a detailed study extended stellar structure SMC using deep colour–magnitude diagrams, obtained as part Survey MAgellanic Stellar History (SMASH). Special care was taken decontamination our data from Milky Way (MW) foreground stars, including globular clusters NGC 362 47 Tuc. We derived surface brightness ‘conservative’...
The Magellanic Clouds are a nearby pair of interacting dwarf galaxies and satellites the Milky Way. Studying their kinematic properties is essential to understanding origin dynamical evolution. They have prominent tidal features kinematics these can give hints about formation dwarfs, galaxy merging stripping gas. In addition they an example that in process with massive galaxy. goal this study investigate Bridge, feature connecting Clouds, using stellar proper motions understand most recent...
We study the morphology of stellar periphery Magellanic Clouds in search substructure using near-infrared imaging data from VISTA Hemisphere Survey (VHS). Based on selection different populations ($J-K_\mathrm{s}$, $K_\mathrm{s}$) colour-magnitude diagram, we confirm presence substructures related to interaction history and find new easter side LMC disc which may be owing influence Milky Way, northern SMC, is probably associated ellipsoidal structure galaxy. also luminosity function red...
We present a deep Cousins RI photometric survey of the open cluster NGC 1960, complete to RC ≃ 22, IC 21, that is used select sample very low mass candidates. Gemini spectroscopy subset these confirm membership and locate age-dependent ‘lithium depletion boundary’ (LDB) – luminosity at which lithium remains unburned in its low-mass stars. The LDB implies age 22 ± 4 Myr quite insensitive choice evolutionary model. 1960 youngest for has been estimated possesses well-populated upper main...
The 32 Orionis group was discovered almost a decade ago and despite the fact that it represents first northern, young (age ~ 25 Myr) stellar aggregate within 100 pc of Sun ($d \simeq 93$ pc), comprehensive survey for members detailed characterisation has yet to be performed. We present large-scale spectroscopic new (predominantly M-type) after combining kinematic photometric data select candidates with Galactic space motion positions in colour-magnitude consistent membership. identify 30...
Galaxy interactions distort the distribution of baryonic matter and can affect star formation. The nearby Magellanic Clouds are a prime example an ongoing galaxy interaction process. Here we use intermediate-age ($\sim1$-$10$ Gyr) red clump stars to map three-dimensional structure Small Cloud (SMC) interpret it within context its history with Large (LMC) Milky Way. Red selected from near-infrared colour-magnitude diagrams based on data VISTA survey Clouds. Interstellar reddening is measured...
We used data from the near-infrared VISTA survey of Magellanic Cloud system (VMC) to measure proper motions (PMs) stars within Small (SMC). The analysed in this study comprise 26 VMC tiles, covering a total contiguous area on sky ~40 deg$^2$. Using multi-epoch observations Ks band over time baselines between 13 and 38 months, we calculated absolute PMs with respect ~130,000 background galaxies. selected sample ~2,160,000 likely SMC member model centre-of-mass motion galaxy. results found for...
Abstract In this paper we report a clustering analysis of upper main-sequence stars in the Small Magellanic Cloud, using data from VMC survey (the VISTA near-infrared YJK s system). Young stellar structures are identified as surface overdensities on range significance levels. They found to be organized hierarchical pattern, such that larger at lower levels contain smaller ones higher have very irregular morphologies, with perimeter–area dimension 1.44 ± 0.02 for their projected boundaries....
We present an $i$-band photometric study of over 800 young stellar objects in the OB association Cep OB3b, which samples timescales from 1 minute to ten years. Using structure functions we show that on all ($\tau$) there is a monotonic decrease variability Class I II through transition disc (TD) systems III, i.e. more evolved are less variable. The Is approximately power-law increase ($\tau^{0.8}$) few minutes II, TDs and III qualitatively different behaviour with most showing up timescale...
We have used medium-resolution spectra to search for evidence that proto-stellar objects accrete at high rates during their early 'assembly phase'. Models predict depleted lithium and reduced luminosity in T-Tauri stars are key signatures of 'cold' high-rate accretion occurring a star's evolution.
We perform a statistical clustering analysis of upper main-sequence stars in the Large Magellanic Cloud (LMC) using data from Visible and Infrared Survey Telescope for Astronomy survey Clouds. map over 2500 young stellar structures at 15 significance levels across ~120 square degrees centred on LMC. The have sizes ranging few parsecs to 1 kpc. find that follow power-law size mass distributions. From perimeter-area relation, we derive dimension 1.44+-0.20. mass-size relation distribution,...
We present a kinematic analysis of the Small Magellanic Cloud using 3700 spectra extracted from European Southern Observatory archive. used data Gaia and near-infrared photometry to select stellar populations discard Galactic foreground stars. The sample includes main-sequence, red giant branch clump stars, observed with Fibre Large Array Multi Wavelength Spectrograph. have resolving power lambda/Delta(lambda) 6500 38000. derive radial velocities by employing full spectrum fitting method...
Understanding the evolutionary history of Magellanic Clouds requires an in-depth exploration and characterization stellar content in their outer regions, which ultimately are key to tracing epochs nature past interactions. We present new deep images a shell-like over-density stars outskirts Small Cloud (SMC). The shell, also detected photographic plates dating back fifties, is located at ~1.9 degr from center SMC north-east direction.The structure this feature were studied with multi-band,...
Abstract The DECam Local Volume Exploration survey (DELVE) is a 126-night program on the 4 m Blanco Telescope at Cerro Tololo Inter-American Observatory in Chile. DELVE seeks to understand characteristics of faint satellite galaxies and other resolved stellar substructures over range environments Volume. will combine new observations with archival data cover ∼15,000 deg 2 high Galactic latitude (∣ b ∣ > 10°) southern sky 5 σ depth g , r i z ∼ 23.5 mag. In addition, region ∼2200 around...