A5005756413- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Spectroscopy and Laser Applications
- Astrophysics and Cosmic Phenomena
- Spectroscopy and Chemometric Analyses
- Impact of Light on Environment and Health
- Adaptive optics and wavefront sensing
- Gaussian Processes and Bayesian Inference
- Astrophysical Phenomena and Observations
- Hydrocarbon exploration and reservoir analysis
- Spectroscopy Techniques in Biomedical and Chemical Research
- Indigenous Studies and Ecology
- Data Analysis with R
- Scientific Research and Discoveries
- Statistical Methods and Inference
- History and Developments in Astronomy
- Atmospheric Ozone and Climate
- Optical Polarization and Ellipsometry
- Machine Learning in Materials Science
- Geochemistry and Geologic Mapping
- Remote Sensing in Agriculture
Canada–France–Hawaii Telescope
2019-2024
University of Toronto
2024
Canadian Institute for Theoretical Astrophysics
2024
University of Hawaii at Hilo
2018-2023
Centre for Research in Astrophysics of Québec
2014-2018
Université Laval
2010-2018
We report here on the discovery of stellar occultations, observed with Kepler, that recur periodically at 15.685 hour intervals, but which vary in depth from a maximum 1.3% to minimum can be less than 0.2%. The star is apparently being occulted KIC 12557548, K dwarf T_eff = 4400 and V 16. Because eclipse depths are highly variable, they cannot due solely transits single planet fixed size. discuss dismiss scenario involving binary giant whose mutual orbit plane precesses, bringing one planets...
We present an overview of SITELLE, Imaging Fourier Transform Spectrometer (iFTS) available at the 3.6-meter Canada-France-Hawaii Telescope. SITELLE is a Michelson-type interferometer able to reconstruct spectrum every light source within its 11' field view in filter-selected bands visible (350 900 nm). The spectral resolution can be adjusted up R = 10 000 and spatial seeing-limited sampled 0.32 arcsec per pixel. describe design instrument as well data reduction analysis process. To...
Abstract Subtracting the changing sky contribution from near-infrared (NIR) spectra of faint astronomical objects is challenging and crucial to a wide range science cases such as estimating velocity dispersions dwarf galaxies, studying gas dynamics in measuring accurate redshifts, any spectroscopic study targets. Since background varies with time location, NIR spectral observations, especially those employing fiber spectrometers targeting extended sources, require frequent sky-only...
The filamentary nebula encompassing the central galaxy of Perseus Cluster, NGC 1275, is a complex structure extending dozens kiloparsecs from 1275. Decades previous works have focused on establishing primary formation and ionization mechanisms in different filaments. These studies pointed to lack star majority filaments, importance magnetic fields turbulence several regions, role interactions between intercluster medium (ICM) cool gas as well interaction radio source, 3C84, In this paper, we...
Abstract The filamentary nebula encompassing the central galaxy of Perseus Cluster, NGC 1275, is a complex structure extending dozens kiloparsecs from 1275. Decades previous works have focused on establishing primary formation and ionization mechanisms in different filaments. These studies pointed to lack star majority filaments, importance magnetic fields turbulence several regions, role interactions between intracluster medium (ICM) cool gas as well interaction radio source, 3C84, In this...
This is the first paper of a series dedicated to nebular physics and chemical evolution nearby galaxies by investigating large samples HII regions with CFHT imaging spectrograph SITELLE. We present technique adapted spectroscopy identify extract parameters from 4285 region candidates found in disc NGC628. Using both spatial spectral capabilities SITELLE, our enables extraction position, dust extinction, velocity, Halpha profile, diffuse ionised gas (DIG) background, luminosity, size,...
SIGNALS, the Star formation, Ionized Gas, and Nebular Abundances Legacy Survey, is a large observing program designed to investigate massive star formation HII regions in sample of local extended galaxies. The will use imaging Fourier transform spectrograph SITELLE at Canada-France-Hawaii Telescope. Over 355 hours (54.7 nights) have been allocated beginning fall 2018 for eight consecutive semesters. Once completed, SIGNALS provide statistically reliable laboratory including over 50 000...
Abstract We present new high-spectral-resolution observations ( R = λ /Δ 7000) of the filamentary nebula surrounding NGC 1275, central galaxy Perseus cluster. These have been obtained with SITELLE, an imaging Fourier transform spectrometer installed on Canada–France–Hawai Telescope a field view <?CDATA $11^{\prime} \times 11^{\prime} $?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>11</mml:mn> <mml:mo accent="false">′</mml:mo> <mml:mo>×</mml:mo>...
As part of the SIGNALS survey, which comprises a sample approximately 40 nearby galaxies observed with Fourier transform spectrometer SITELLE, we present study metal mixing in spiral galaxy NGC 6946. Taking advantage blue sensitivity our setup, measure oxygen and nitrogen abundances 638 H II regions, focus analysis on abundance fluctuations about radial gradients. We detect an azimuthal variation 0.1 dex these across NE arm, leading edge being more metal-poor than trailing edge. This result...
Abstract As part of the SIGNALS survey, which comprises a sample approximately 40 nearby galaxies observed with Fourier transform spectrometer SITELLE, we present study metal mixing in spiral galaxy NGC 6946. Taking advantage blue sensitivity our setup, measure oxygen and nitrogen abundances 638 H ii regions, focus analysis on abundance fluctuations about radial gradients. We detect an azimuthal variation 0.1 dex these across NE arm, leading edge being more metal-poor than trailing edge....
We present the {\sc warpfield} emission predictor, warpfield-emp}, which couples 1D stellar feedback code with cloudy} \hii region/PDR and polaris} radiative transfer code, in order to make detailed predictions for time-dependent line continuum arising from H{\sc ii} region PDR surrounding an evolving star cluster. warpfield-emp} accounts a wide range of physical processes (stellar winds, supernovae, radiation pressure, gravity, thermal conduction, cooling, dust extinction etc.) yet runs...
In the second paper of this series, we developed a new distance determination method using median $J$ magnitude carbon-rich asymptotic giant branch stars (CS) as standard candles and Magellanic Clouds fundamental calibrators. The $J$-band CS luminosity function was modeled modified Lorentzian distribution whose parameters were used to determined whether LMC or SMC most suitable calibrator. third expand our sample galaxies introduce more robust determine model. fitting uses an un-binned...
The J-region asymptotic giant branch (JAGB) method is a new standard candle that based on the stable intrinsic J-band magnitude of color-selected carbon stars, and has precision comparable to other primary distance indicators such as Cepheids TRGB. We further test accuracy JAGB in Local Group Galaxy M33. M33's moderate inclination, low metallicity, nearby proximity make it an ideal laboratory for tests systematics local indicators. Using high-precision optical BVI near-infrared JHK...
We present a large VLT/MUSE mosaic (3.8 x 3.8 kpc) of the nearby spiral galaxy M83, with spatial resolution ~20 pc. obtained kinematics stars and ionised gas, compared them molecular gas from ALMA CO(2-1). separated into HII regions diffuse (DIG) determined fraction Ha luminosity originating DIG (f_DIG). observe that both trace galactic disk rotation, as well fast-rotating nuclear component, likely connected to secular processes driven by bar. In kinematics, we stream east nucleus,...
We introduce a new distance determination method using carbon-rich asymptotic giant branch stars (CS) as standard candles and the Large Small Magellanic Clouds (LMC SMC) fundamental calibrators. select samples of CS from ($(J-K_{s})_0$, $J_0$) colour-magnitude diagrams, as, in this combination filters, are bright easy to identify. fit $J$-band luminosity functions Lorentzian distribution modified allow be asymmetric. use parameters best-fit determine if function given galaxy resembles that...
ABSTRACT We present the first optical identification and confirmation of a sample supernova remnants (SNRs) in nearby galaxy NGC 3344. Using high spectral spatial resolution data, obtained with CFHT imaging Fourier transform spectrograph SITELLE, we identified about 2200 emission line regions, many which are H ii diffuse ionized gas also SNRs. Considering stellar population background, quite important 3344, have selected 129 SNR candidates based on four criteria for regions where lines flux...
ABSTRACT The ionizing radiation of young and massive stars is a crucial form stellar feedback. Most (Lyman-continuum; LyC, λ &lt; 912Å) photons are absorbed close to the that produce them, forming compact H ii regions, but some escape into wider galaxy. Quantifying fraction LyC an open problem. In this work, we present seminovel method estimate by combining broadband photometry star clusters from Legacy ExtraGalactic UV Survey (LEGUS) with regions observed Star formation, Ionized gas,...
We describe the concept of a new instrument for Canada-France-Hawaii telescope (CFHT), SITELLE (Spectromètre Imageur à Transformée de Fourier pour l'Etude en Long et Large raies d'Emission), as well science case and technical study its preliminary design. will be an imaging transform spectrometer capable obtaining visible (350 nm - 950 nm) spectrum every source light in field view 15 arcminutes, with 100% spatial coverage spectral resolution ranging from R = 1 (deep panchromatic image) to...
ABSTRACT Using datacubes from the imaging Fourier transform spectrometer SITELLE at Canada–France–Hawaii Telescope as part of star formation, ionized gas, and nebular abundances legacy survey, we identify 15 new planetary nebulae (PNe) well five supernova remnants (SNRs) in outer parts nearby dwarf starburst galaxy NGC 4214. These data also allow us to study morphology kinematics all 18 known SNRs this galaxy. We highlight use a $\xi = \sigma \frac{\rm {[S{\small \,II}]}}{\rm {H\alpha }}$...
SITELLE is a novel integral field unit spectroscopy instrument that has an impressive spatial (11 by 11 arcmin), spectral coverage, and resolution (R=1-20000). SIGNALS anticipated to obtain deep observations (down 3.6x10-17ergs s-1cm-2) of 40 galaxies, each needing complex substantial time extract information. We present method uses Convolution Neural Networks (CNN) for estimating emission line parameters in optical spectra obtained with as part the large program. Our algorithm trained...
The star formation efficiency (SFE) has been shown to vary across different environments, particularly within galactic starbursts and deep the bulges of galaxies. Various quenching mechanisms may be responsible, ranging from dynamics feedback active nuclei (AGN). Here, we use spatially-resolved observations warm ionised gas emission lines imaging Fourier transform spectrograph SITELLE at Canada-France-Hawaii Telescope (CFHT) cold molecular (CO(2-1)) Atacama Large Millimeter/sub-millimeter...
Imaging Fourier transform spectroscopy (iFTS) is a promising, although technically very challenging, option for wide-field hyperspectral imagery. We present in this paper an introduction to the iFTS concept and its advantages drawbacks, as well examples of data obtained with prototype iFTS, SpIOMM, attached 1.6 m telescope Observatoire du Mont-Mégantic: emission line ratios spiral galaxy NGC 628 absorption indices giant elliptical M87. conclude by introducing SpIOMM's successor, SITELLE,...
In the first paper of this series (Rhea et al. 2020), we demonstrated that neural networks can robustly and efficiently estimate kinematic parameters for optical emission-line spectra taken by SITELLE at Canada-France-Hawaii Telescope. This expands upon notion developing an artificial network to line ratios strong emission-lines present in SN1, SN2, SN3 filters SITELLE. We construct a set 50,000 synthetic using from Mexican Million Model database replicating Hii regions. Residual analysis on...
Abstract Diagnostic diagrams of emission-line ratios have been used extensively to categorize extragalactic emission regions; however, these diagnostics are occasionally at odds with each other due differing definitions. In this work, we study the applicability supervised machine-learning techniques systematically classify regions from certain lines. Using Million Mexican Model database, which contains information grids photoionization models using cloudy, and shock models, develop training...
The SITELLE Imaging Fourier Transform Spectrometer was successfully commissioned at the Canada France Hawaii Telescope starting in July 2015. Here we discuss commissioning process, outcome of early tests on-sky as well ensuing work to optimize modulation efficiency large optical path difference and image quality instrument.