The Crescent Nebula, NGC 6888, has long been the muse of many scientific and amateur research. However, the recent data provided by SITELLE, a wide-field imaging Fourier transform spectrometer at the Canada-France-Hawaii telescope call for new analysis and conclusions. The spectral cubes offer a field of view of 11 × 11 arcminutes2 and have been acquired trough 5 different filter-selected bands covering the optical waveband (from 350 to 680 nm), allowing 23 characteristic emission optical lines to be described with a spectral resolution reaching up to 2500. Doppler shifting allow two-components velocity fits, describing the multi-layered bubble’s kinematics. The sulfur doublet describes electronic densities. Other faint lines (including [NII] 5755, [OIII] 4363 and NeIII 3868) are essential to determine accurate temperatures and abundances. Emission lines are key to this nebular research, but absorption lines in the spectrum of hundreds of field stars are also studied. All this leads to a more complete physical description of NGC 6888, its central star WR136 and the stars present in the field of view.
We present data taken with the imaging Fourier transform spectrograph SITELLE, at the Canada-France-Hawaii Telescope, of the nearby dwarf starburst galaxy NGC 4214. From these data, we identify 18 new planetary nebula candidates in the outer part of the galaxy. For each planetary nebula, we provide the flux of the strong emission lines, the [Oiii]λλ5007,4959 Hα and Hβ, as well as the radial velocity. We also provide the kinematics for 13 of the 17 planetary nebulae previously discovered in the central part of the galaxy with HST data by Dopita et al. (2010). We present a novative technique to obtain accurate velocity measurement for objects with [Oiii] emission but without Hα emission with SITELLE. We use the [Oiii] emission line luminosity function of the planetary nebulae to establish a new velocity-independent distance for the galaxy. This method gives a distance D = 3.31+0.20 −0.27 Mpc for NGC 4214.
Ionized gas is a key component for understanding star formation within galaxies. As part of SIGNALS, a survey that focuses on the emission regions of about 40 nearby star-forming galaxies, NGC 925 was observed with SITELLE, an imaging Fourier transform spectrometer for the optical spectrum built in Qu´ebec City (U. Laval and ABB) and installed at the Canada-France-Hawaii Telescope. This work mainly focuses on HII regions; establishing the physical characteristics of these regions will yield reliable insight regarding the influence of local environments on star formation and the different star-forming mechanisms at play. At a distance of 9.2 Mpc, NGC 925 is a fine candidate in SIGNALS framework, due to SITELLE’s high spatial resolution of 0.32”/pixel and large field of view of 11’x11’, HII regions are differentiated from one another over the whole galaxy. Using Hα to locate emission regions, we compute BPT diagrams for these regions using the emission line ratios [OIII]/Hβ and [NII]/Hα. A catalog of HII regions is compiled from these diagrams. The preliminary results presented in this work (i.e., a young bar, an asymmetric distribution of HII regions and recent star formation) suggest that NGC 925 may be the result of an interaction with another member of NGC 1023 group. Simulations of galaxy interactions and multiwavelength observations will be acquired to confirm this hypothesis.
We present a technical and scientific overview of SITELLE, an imaging Fourier transform spectrometer in the visible band installed at the Canada-France-Hawaii telescope, and highlight some of its most interesting results, from nearby nebulae to clusters of galaxies. SITELLE represents a total incongruity in the world of Fourier transform spectroscopy, being used in the visible range down to 350 nm, presenting a large field of view (11′′×11′′) and collecting more than four million spectra per data cube. Among its noteworthy achievements, SITELLE obtained the first realistic 3D views of the AT Cnc dwarf nova ejecta and of the Crab supernova remnant, a unique collection of emission line maps of a large sample of nearby galaxies, as well as the detection of ram pressure effects on star-forming galaxies in a cluster 3 billion light-years from us.
The SITELLE Imaging Fourier Transform Spectrometer was successfully commissioned at the Canada France Hawaii Telescope starting in July 2015. Here we discuss the commissioning process, the outcome of the early tests on-sky as well as the ensuing work to optimize the modulation efficiency at large optical path difference and the image quality of the instrument.
A new polarimeter has been built for the “Observatoire du Mont-Mégantic” (POMM) and is now in commissioning
phase. It will allow polarization measurements with a precision of 10-6, an improvement by a factor of 100 over the
previous observatory polarimeter. The characteristics of the instrument that allow this goal are briefly discussed and the
planned science observations are presented. They include exoplanets near their host star (hot Jupiters), transiting
exoplanets, stars with debris disks, young stars with proto-planetary disks, brown dwarfs, massive Wolf-Rayet stars and
comets. The details of the optical and mechanical designs are presented in two other papers.
SITELLE is an imaging FTS that will become a guest instrument at the Canada-France-Hawaii telescope (CFHT) by the
end of 2014. This paper describes the final optical design of SITELLE, shows how the compliance of the sub-optical
components with the design was evaluated, and presents results of the measured optical quality.
We report here on the current status of SITELLE, an imaging Fourier transform spectrometer to be installed on the
Canada-France Hawaii Telescope in 2013. SITELLE is an Integral Field Unit (IFU) spectrograph capable of obtaining
the visible (350 nm – 900 nm) spectrum of every pixel of a 2k x 2k CCD imaging a field of view of 11 x 11 arcminutes,
with 100% spatial coverage and a spectral resolution ranging from R = 1 (deep panchromatic image) to R < 104 (for gas
dynamics). SITELLE will cover a field of view 100 to 1000 times larger than traditional IFUs, such as GMOS-IFU on
Gemini or the upcoming MUSE on the VLT. SITELLE follows on the legacy of BEAR, an imaging conversion of the
CFHT FTS and the direct successor of SpIOMM, a similar instrument attached to the 1.6-m telescope of the
Observatoire du Mont-Mégantic in Québec. SITELLE will be used to study the structure and kinematics of HII regions
and ejecta around evolved stars in the Milky Way, emission-line stars in clusters, abundances in nearby gas-rich
galaxies, and the star formation rate in distant galaxies.
SpIOMM (Spectromètre-Imageur de l'Observatoire du Mont Mégantic) is still the only operational astronomical
Imaging Fourier Transform Spectrometer (IFTS) capable of obtaining the visible spectrum of every source of
light in a field of view of 12 arc-minutes. Even if it has been designed to work with both outputs of the Michelson
interferometer, up to now only one output has been used. Here we present ORBS (Outils de Réduction Binoculaire
pour SpIOMM/SITELLE), the reduction software we designed in order to take advantage of the two output data.
ORBS will also be used to reduce the data of SITELLE (Spectromètre-Imageur pour l' Étude en Long et en Large
des raies d' Émissions) { the direct successor of SpIOMM, which will be in operation at the Canada-France-
Hawaii Telescope (CFHT) in early 2013. SITELLE will deliver larger data cubes than SpIOMM (up to 2 cubes
of 34 Go each). We thus have made a strong effort in optimizing its performance efficiency in terms of speed
and memory usage in order to ensure the best compliance with the quality characteristics discussed with the
CFHT team. As a result ORBS is now capable of reducing 68 Go of data in less than 20 hours using only 5 Go
of random-access memory (RAM).
We present new data obtained with SpIOMM, the imaging Fourier transform spectrometer attached to the 1.6-m
telescope of the Observatoire du Mont-Megantic in Québec. Recent technical and data reduction improvements have
significantly increased SpIOMM's capabilities to observe fainter objects or weaker nebular lines, as well as continuum
sources and absorption lines, and to increase its modulation efficiency in the near ultraviolet. To illustrate these
improvements, we present data on the supernova remnant Cas A, planetary nebulae M27 and M97, the Wolf-Rayet ring
nebula M1-67, spiral galaxies M63 and NGC 3344, as well as the interacting pair of galaxies Arp 84.
Patrick Côte, Alan Scott, Michael Balogh, Ron Buckingham, David Aldridge, Ray Carlberg, Weiguo Chen, Jean Dupuis, Clinton Evans, Laurent Drissen, Wes Fraser, Frederic Grandmont, Paul Harrison, John Hutchings, JJ Kavelaars, John-Thomas Landry, Christian Lange, Denis Laurin, Tarun Patel, Venka Pillay, Louis Piche, Andres Rader, Carmelle Robert, Marchin Sawicki, Robert Sorba, Guillaume Theriault, Ludovic Van Waerbeke
The Cosmological Advanced Survey Telescope for Optical and UV Research (CASTOR) is a proposed CSA
mission that would make a unique, powerful, and lasting contribution to astrophysics by providing panoramic,
high-resolution imaging in the UV/optical (0.15 - 0.55 μm) spectral region. This versatile `smallSAT'-class
mission would far surpass any ground-based optical telescope in terms of angular resolution, and would provide
ultra-deep imaging in three broad lters to supplement longer-wavelength data from planned international dark
energy missions (Euclid, WFIRST) as well as from the ground-based Large Synoptic Survey Telescope (LSST).
Combining the largest focal plane ever
own in space, with an innovative optical design that delivers HST-quality
images over a eld two orders of magnitude larger than Hubble Space Telescope (HST), CASTOR would image
about 1/8th of the sky to a (u-band) depth ~1 magnitude fainter than will be possible with LSST even after a
decade of operations. No planned or proposed astronomical facility would exceed CASTOR in its potential for
discovery at these wavelengths.
We describe the concept of a new instrument for the Canada-France-Hawaii telescope (CFHT), SITELLE (Spectromètre
Imageur à Transformée de Fourier pour l'Etude en Long et en Large de raies d'Emission), as well as a science case and
a technical study of its preliminary design. SITELLE will be an imaging Fourier transform spectrometer capable of
obtaining the visible (350 nm - 950 nm) spectrum of every source of light in a field of view of 15 arcminutes, with 100%
spatial coverage and a spectral resolution ranging from R = 1 (deep panchromatic image) to R = 104 (for gas dynamics).
SITELLE will cover a field of view 100 to 1000 times larger than traditional integral field spectrographs, such as
GMOS-IFU on Gemini or the future MUSE on the VLT. It is a legacy from BEAR, the first imaging FTS installed on
the CFHT and the direct successor of SpIOMM, a similar instrument attached to the 1.6-m telescope of the Observatoire
du Mont-Mégantic in Québec. SITELLE will be used to study the structure and kinematics of HII regions and ejecta
around evolved stars in the Milky Way, emission-line stars in clusters, abundances in nearby gas-rich galaxies, and the
star formation rate in distant galaxies.
SpIOMM is an imaging Fourier transform spectrometer designed to obtain the visible range (350 - 850 nm) spectrum of
every light source in a circular field of view of 12 arcminutes in diameter. Attached to the 1.6-m telescope of the
Observatoire du Mont Megantic in southern Quebec. We present here some results of three successful observing runs in
2007, which highlight SpIOMM's capabilities to map emission line objects over a very wide field of view and a broad
spectral range. In particular, we discuss data cubes from the planetary nebula M27, the supernova remnants NGC 6992
and M1, the barred spiral galaxy NGC7479, as well as Stephan's quintet, and interacting group of galaxies.
We present the most recent technical improvements on SpIOMM, an Imaging Fourier Transform Spectrometer (IFTS)
attached to the 1.6 telescope of the Mont Megantic Observatory. The recent development of SpIOMM demonstrates that
the concept of IFTS for ground telescopes is a promising astronomical 3D spectroscopy technique for multi-object
spectroscopy and multi-band imaging. SpIOMM has been developed through a collaboration between Universite Laval
and the industry (ABB Bomem). It is designed for optical observations from the near UV (350 nm) to the near IR (850
nm) with variable spectral resolution. The circular FOV of the instrument covers 12' in diameter. We have recently
improved the servo system algorithm which now controls the mirror displacement and alignment at a rate of ~7kHz.
Hardware improvements to the servo and the metrology system will be described along with their impacts on
performance in the laboratory and in observing conditions. The instrument has successfully been operated at the 1.6
meter telescope this year using the revised control systems and acquired several datacubes. We will discuss some issues
regarding the sensitivity to environmental conditions implied by the use of such an instrument. An overview of the
datacube reduction procedure will show some solutions proposed for observational problems encountered that affect the
quality of the data such as sky transmission variations, wind, changing gravity vector and temperature.
The advent of wide-field imagers on large telescopes (Megacam at CFHT, Suprime-Cam at Subaru, and others)
with degree-wide fields of view is largely motivated by a renewed interest in our own solar system, in the history
of the Milky Way and its neighbors, and in the large-scale structure of the Universe. Smaller, university-based
telescopes can of course also benefit from wide-field imagery. We present in this paper the design and first
results of Panoramix-II, the new wide-field imager of the Mont Megantic Observatory (OMM). This instrument
is conceptually a focal reducer designed to image and correct the F/8 cassegrain focal plane of the telescope onto
a pair of 2KX4K EEV detectors. The camera is optimized for the SLOAN g' (410-550 nm), r' (550-690 nm), i'
(690-850 nm) and z' (850-950 nm) wave bands. The sky will be imaged onto the focal plane at an image scale
of 0.52 arcsecond per 13.5 μm pixel. The design image quality is 1.00 arcsecond 50% diffraction encircled
energy over the central 35 arcmin field and no images worse than 1.25 arcsecond over the 49 arcminute diameter
camera field. The optical design distortion at the corners is less than 1%. The Panoramix-II camera has a filter
wheel at the internal stop. Panoramix-II can also support the FaNTOmM photon-counting camera used in
conjunction with a Fabry-Perot interferometer to provide spectrometric data.
We present an overview of SpIOMM, an Imaging Fourier Transform Spectrometer (IFTS) for astronomy developed at University Laval in collaboration with ABB, INO and the Canadian Space Agency. SpIOMM, attached to the 1.6 meter (f/8) telescope at the Observatoire du mont Megantic in Quebec. It is a Michelson-type interferometer capable of
obtaining the visible spectrum (from 350 nm to 900 nm) of every light source within its 12 arcminute circular field of view. This design will allow the correction of variable sky transmission. It consists of a dual output port and the total throughput is exploited by two CCDs used as detectors. We present the concept and design of this unique instrument. A metrology system combined with a dynamic alignment assures a good sampling and mirror alignment during the entire acquisition sequence. This particular servo control is explained and demonstrated and its capabilities and performance
are discussed. We introduce the use of specific bandpass filters centered on the most important groups of emission lines which, when combined with spectral folding algorithms, allows us to reach high spectral resolution (R = 25 000, or 1 cm-1). Astronomical data collected by SpIOMM in 2004-2005 are also presented.
In this paper, we present the optical design of the optical train of Panoramix-II, a wide-field VIS-NIR camera to be installed at the cassegrain focus of OMM (Observatoire du Mont Megnantic, Quebec, Canada). This camera is optimized for g (0.41-0.55), r (0.556-0.689), i (0.693-0.867) and z (0.851-0.95) operating region and used a 2kX4k EEV detector. The sky will be imaged onto the focal plane at an optical speed of F/2.35 yielding an image scale of 0.75 arcsecond per 13.5 μm pixel. The design image quality is 0.75 arcsecond 50% diffraction encircled energy over the central 27 arcmin field and no images worse than 0.85 arcsecond over the 55 arcminute diameter camera field. The optical design distortion at the corners is less than 0.08%. The Panoramix-II camera have a set of filters is used at the internal pupil. The image of the pupil is sufficiently sharp to limit the filter size. We discuss the principle characteristics of the imager, the specifications, the optical design, the performances, a ghost study and finally a tolerance anlaysis.
We present an overview of the past and current development of the Imaging Fourier Transform Spectrometer (IFTS) concept for ground telescopes produced in collaboration between ABB Bomem and Université Laval. This instrument intends to produce spectra of variable resolutions up to R = λ/Δλ = 10 000 from the near UV to the near IR (350 nm to 900 nm). It is designed to fit the f/8 focus of the Mont Mégantic 1.6m optical telescope in Québec. The large number of spatial elements (> 1 million pixels) is the novel aspect of this FTS design along with innovative metrology system. Heritage from Next Generation Space Telescope (NGST) IFTS concept, Lawrence Livermore National Laboratory (LLNL)- ABB Bomem instrument and commercial ABB Bomem DA series FTS are reviewed. Techniques for accurately servoing the moving mirror alignment to a value smaller than 0.1 arc second and position to sub nanometer value are discussed. Also presented are results from the assembled interferometer sub-system.
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