A5055871504- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- History and Developments in Astronomy
- Galaxies: Formation, Evolution, Phenomena
- Adaptive optics and wavefront sensing
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Astronomical and nuclear sciences
- Astrophysical Phenomena and Observations
- Advanced Thermodynamic Systems and Engines
- Calibration and Measurement Techniques
- Geological and Geochemical Analysis
- Planetary Science and Exploration
- Spectroscopy and Laser Applications
- Crystal Structures and Properties
- High-pressure geophysics and materials
- Academic and Historical Perspectives in Psychology
- Historical Astronomy and Related Studies
- Atmospheric chemistry and aerosols
- Teacher Professional Development and Motivation
Mount Saint Vincent University
2015-2025
Washtenaw Community College
2023
Hunter College
2023
Canada Foundation for Innovation
2023
Natural Sciences and Engineering Research Council
2023
Compute Canada
2023
Saint Mary's University
2012-2021
St. Mary's University, Texas
2014
Abbey Ridge Observatory
2009-2012
Stillwater (Canada)
2009-2012
Context. The ESO public survey VISTA variables in the Vía Láctea (VVV) started 2010. VVV targets 562 sq. deg Galactic bulge and an adjacent plane region is expected to run for about five years.
Classical and Type II Cepheids are used to reinvestigate specific properties of the Galaxy. A new reddening-free Cepheid distance parameterization is formulated from LMC (OGLE), with uncertainties typically no larger than 5-15%. Galactic centre R0=7.8+-0.6 kpc derived median in bulge R0=7.7+-0.7 a near side combined an estimated radius 1.3+-0.3 planetary nebulae. The Sun plane inferred classical variables Zsun=26+-3 pc, result dependent on sample's direction because complicating effects...
Context. The ESO public survey VISTA Variables in the Vía Láctea (VVV) surveyed inner Galactic bulge and adjacent southern disk from 2009–2015. Upon its conclusion, complementary VVV extended (VVVX) has expanded both temporal as well spatial coverage of original area, widening it 562 to 1700 sq. deg., providing additional epochs JHK s filters 2016–2023. Aims. With completion VVVX observations during first semester 2023, we present here observing strategy, a description data quality access,...
VISTA Variables in the V\'ia L\'actea (VVV) is one of six ESO Public Surveys using 4 meter Visible and Infrared Survey Telescope for Astronomy (VISTA). The VVV survey covers Milky Way bulge an adjacent section disk, principal objectives to search new star clusters within previously unreachable obscured parts Galaxy. primary motivation behind this work discover analyze direction inner Galactic disk bulge. Regions covered by were visually inspected composite JHKs color images select cluster...
We use deep multi-epoch near-IR images of the VISTA Variables in V\'ia L\'actea (VVV) Survey to search for RR Lyrae stars towards Southern Galactic plane. Here we report discovery a group close together VVV tile d025. Inspection and PSF photometry reveals that most these are likely belong globular cluster, matches position previously known star cluster FSR\,1716. The stellar density map field yields $>100$ sigma detection this candidate is centered at equatorial coordinates...
Context . High reddening near the Galactic plane hampers observations and proper characterization of globular clusters (GCs) located toward inner regions Milky Way. Aims The VISTA Variables in Vía Láctea (VVV) survey observed bulge adjacent disk for several years, providing multi-epoch, near-infrared images 41 GCs. Detecting RR Lyrae variable stars belonging to these GCs will aid their accurate parameterization. Methods By fully leveraging astrometric, photometric, variability VVV catalogs,...
High reddening near the Galactic plane hampers observations and proper characterization of globular clusters (GCs) located toward inner regions Milky Way. The VISTA Variables in Via Lactea (VVV) survey observed bulge adjacent disk for several years, providing multi-epoch, near-infrared images 41 GCs. Detecting RRLyrae variables belonging to these GCs will aid their accurate parameterization. By fully leveraging astrometric, photometric, variability VVV catalogs, we searched stars associated...
Pre-Gaia distances for the open cluster Pismis 19 disagree with Gaia parallaxes. A 2MASS $JK_s$ red clump distance was therefore established ($2.90\pm0.15$ kpc), which reaffirms that zero-point corrections are required (e.g., Lindegren et al.~2021). OGLE GD-CEP-1864 is confirmed as a member of on basis DR3 proper motions, and its 2MASS+VVV color-magnitude position near tip turnoff. That $0^{\rm d}.3$ variable star likely $\delta$ Scuti rather than classical Cepheid. The case revealed...
Abstract A debate persists regarding the correlation between DIBs 9577 and 9632 Å, whether they share a common molecular carrier (i.e., C$_{60}^{+}$). robust high determination emerges after bridging baseline across an order of magnitude (≃ 50 − 700 mÅ, r = 0.93 ± 0.02), nearly doubling important higher equivalent width domain by adding seven new Mg II-corrected sightlines. Moreover, additional evidence is presented possible DIB linkages to fullerenes, whereby attention drawn at 7470.38,...
Abstract Pre-Gaia distances for the open cluster Pismis 19 disagree with Gaia parallaxes. A Two Micron All Sky Survey (2MASS) JK s red clump distance was therefore established (2.90 ± 0.15 kpc), which reaffirms that zero-point corrections are required. OGLE GD-CEP-1864 is confirmed as a member of on basis DR3 proper motions and its 2MASS+Vista Variables in Vía Láctea color–magnitude position near tip turnoff. That 0.3 day variable star likely δ Scuti rather than classical Cepheid. The case...
Context. The ESO Public Survey “VISTA Variables in the Vía Láctea” (VVV) provides deep multi-epoch infrared observations for unprecedented 562 sq. degrees of Galactic bulge, and adjacent regions disk.
Solid insight into the physics of inner Milky Way is key to understanding our Galaxy's evolution, but extreme dust obscuration has historically hindered efforts map area along Galactic mid-plane. New comprehensive near-infrared time-series photometry from VVV Survey revealed 35 classical Cepheids, tracing a previously unobserved component Galaxy, namely ubiquitous thin disk young stars mid-plane, traversing across bulge. The discovered period (age) spread these Cepheids implies continuous...
Abstract RR Lyrae stars (RRLs) are tracers of the Milky Way’s fossil record, holding valuable information on its formation and early evolution. Owing to high interstellar extinction endemic Galactic plane, distant RRLs lying at low latitudes have been elusive. We attained a census 1892 high-confidence by exploiting near-infrared photometric database VVV survey’s disk footprint spanning ∼70° longitude, using machine-learned classifier. Novel data-driven methods were employed accurately...
The new multi-epoch near-infrared VISTA Variables in the Vía Láctea (VVV) survey is sampling 562 deg2 of Galactic bulge and adjacent regions disk. Accurate astrometry established for region surveyed allows VVV data to be merged with overlapping surveys (e.g., GLIMPSE, WISE, 2MASS, etc.), thereby enabling construction longer baseline spectral energy distributions astronomical targets. However, order maximize use data, a set transformation equations are required place JHKs photometry onto...
Concerns are raised regarding the S$H_0$ES results, and present $H_0$ controversy. The $H_0 \simeq 73$ km/s/Mpc has remained relatively unaltered across $18$ years (2005-2023), despite marked shifts in maser Cepheid distances to keystone galaxy NGC4258 (M106), changes slope, zeropoint, metallicity, extinction terms tied Leavitt Law, notwithstanding uncertain photometry for remote Cepheids spanning galaxies with highly inhomogeneous crowding surface brightness profiles. findings by fellow...
ABSTRACT SH0ES VI-band photometry for classical Cepheids in the keystone galaxy NGC4258 yield discrepant absolute magnitudes. Specifically, 2016 and 2022 published Cepheid data exhibit a substantial offset of ΔW0, VI ≃ 0m.3. That adds to suite existing concerns associated with analysis, which sum imply that their relatively non-changing Hubble constant nearly 20 years warrants scrutiny.
Context: The ESO Public Survey "VISTA Variables in the V\'ia L\'actea" (VVV) provides deep multi-epoch infrared observations for an unprecedented 562 sq. degrees of Galactic bulge, and adjacent regions disk. In this survey nearly 150 new open clusters cluster candidates have been discovered. Aims: This is second a series papers about young, massive observed using VVV survey. We present first study six recently discovered clusters. These contain at least one newly Wolf-Rayet (WR) star....
Evidence is presented which supports findings that the classical Cepheid VIC period Wesenheit function relatively insensitive to metallicity. The viability of a recently advocated strong metallicity dependence was evaluated by applying proposed correction (γ = −0.8 mag dex−1) distances established for Magellanic Clouds via Galactic calibration, anchored 10 nearby Cepheids with measured Hubble Space Telescope (HST) parallaxes. resulting γ-corrected (e.g., Small Cloud, μ0, γ ∼ 18.3) are in...
Milky Way globular clusters (MW GCs) are difficult to identify at low Galactic latitudes because of high differential extinction and heavy star crowding. The new deep near-IR images photometry from the VISTA Variables in Via L\'actea Extended Survey (VVVX) allow us chart previously unexplored regions. Our long term aim is complete census MW GCs. immediate goals estimate astrophysical parameters, measuring their reddenings, extinctions, distances, total luminosities, proper motions, sizes,...
We report the discovery of a pair extremely reddened classical Cepheid variable stars located in Galactic plane behind bulge, using near-infrared time-series photometry from VVV Survey. This is first time that such objects have ever been found opposite side plane. The Cepheids almost identical periods, apparent brightnesses and colors. From Leavitt law, we determine their distances with ~1.5% precision ~8% accuracy. find they same total extinction A(V)~32 mag, are at heliocentric distance...
Near-infrared color-excess and extinction ratios are essential for establishing the cosmic distance scale probing Galaxy, particularly when analyzing targets attenuated by significant dust. A robust determination of those followed from leveraging new infrared observations VVV survey, wherein numerous bulge RR Lyrae Type II Cepheids were discovered, in addition to $BVJHK_{s}(3.4\rightarrow22)\mu m$ data classical O-stars occupying broader Galaxy. The apparent optical vary significantly with...
The windows of low extinction in the Milky Way (MW) plane are rare but important because they enable us to place structural constraints on opposite side Galaxy, which has hitherto been done rarely. We use near-infrared (near-IR) images VISTA Variables V\'ia L\'actea (VVV) Survey build maps and identify towards Southern Galactic plane. Here we report discovery VVV WIN 1713$-$3939, a very interesting window with relatively uniform conveniently placed close new roughly 30 arcmin diameter is...