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We report CFHT/SITELLE imaging Fourier Transform Spectrograph observations of the Brightest Cluster Galaxy (BCG) of galaxy cluster Abell 2390 at z=0.228. The BCG displays a prominent cone of emission in H$\alpha$, H$\beta$, [NII], and [OII] to the North-West with PA = 42$^o$, 4.4 arcsec in length (15.9 kpc), which is associated with elongated and asymmetric Chandra soft X-ray emission. The H$\alpha$ flux map also contains a "hook" of H$\alpha$ and [NII] emission resulting in a broadened northern edge to the cone. Using SITELLE/LUCI software we extract emission line flux, velocity, velocity dispersion, and continuum maps, and utilize them to derive flux ratio maps to determine ionization mechanisms and dynamical information in the BCG's emission line region. The Baldwin-Phillips-Terlevich diagnostics on the BCG cone indicate a composite ionization origin of photoionization due to star formation and shock. Strong LINER-like emission is seen in the nuclear region which hosts an AGN. As Abell 2390 is a cool-core cluster, we suggest that the cooling flow is falling onto the central BCG and interacting with the central AGN. The AGN produces jets that inflate "bubbles" of plasma in the ICM, as is often observed in local galaxy clusters. Furthermore, combining signs of AGN activities from radio, optical emission line and X-ray data over a large range of physical scale, we find evidence for three possible episodes of AGN activity in different epochs associated with the Abell 2390 BCG., Comment: 15 pages, 13 figures, accepted by MNRAS

We present the results from the HST WFC3 and ACS data on an archetypal galaxy undergoing ram pressure stripping (RPS), ESO 137-001, in the nearby cluster Abell 3627. ESO 137-001 is known to host a prominent stripped tail detected in many bands from X-rays, Halpha to CO. The HST data reveal significant features indicative of RPS such as asymmetric dust distribution and surface brightness as well as many blue young star complexes in the tail. We study the correlation between the blue young star complexes from HST, HII regions from Halpha (MUSE) and dense molecular clouds from CO (ALMA). The correlation between the HST blue star clusters and the HII regions is very good, while their correlation with the dense CO clumps are typically not good, presumably due in part to evolutionary effects. In comparison to the Starburst99+Cloudy model, many blue regions are found to be young (< 10 Myr) and the total star formation (SF) rate in the tail is 0.3 - 0.6 M_Sun/yr for sources measured with ages less than 100 Myr, about 40% of the SF rate in the galaxy. We trace SF over at least 100 Myr and give a full picture of the recent SF history in the tail. We also demonstrate the importance of including nebular emissions and a nebular to stellar extinction correction factor when comparing the model to the broadband data. Our work on ESO 137-001 demonstrates the importance of HST data for constraining the SF history in stripped tails., 22 pages, 20 figures, 4 tables, published in MNRAS 06/2023

The multi-object spectrograph (MOS) has been the benchmark for the current generation of astronomical spectrographs, valued for its ability to acquire the spectra of hundreds of objects simultaneously. In the last two decades, the digital micromirror device (DMD) has shown potential in becoming the central component of the MOS, being used as a programmable slit array. We have designed a seeing-limited DMD-based MOS covering a spectral range of 0.4 to 0.7 $\mu$m, with a field of view (FOV) of $10.5^\prime \times 13.98^\prime$ and a spectral resolution of $R\sim1000$. This DMD-MOS employs all-spherical refractive optics, and a volume phase holographic (VPH) grism as the dispersive element for high throughput. In this paper, we present the optical design and optimization process of this DMD-MOS, as well as a preliminary wavelength calibration procedure for hyperspectral data reduction. Using simulated data of the DMD-MOS, a procedure was developed to measure hyperspectral imaging distortion and to construct pixel-to-wavelength mappings on the detector. An investigation into the relationships between DMD micromirrors and detector pixels was conducted. This DMD-MOS will be placed on a 0.5 m diameter telescope as an exploratory study for future DMD-based MOS systems., Comment: 15 pages, 32 figures, 1 table, SPIE Astronomical Telescopes + Instrumentation 2022

The MMTO Adaptive optics exoPlanet characterization System (MAPS) is an ongoing upgrade to the 6.5-meter MMT Observatory on Mount Hopkins in Arizona. MAPS includes an upgraded adaptive secondary mirror (ASM), upgrades to the ARIES spectrograph, and a new AO system containing both an optical and near-infrared (NIR; 0.9-1.8 um) pyramid wavefront sensor (PyWFS). The NIR PyWFS will utilize an IR-optimized double pyramid coupled with a SAPHIRA detector: a low-read noise electron Avalanche Photodiode (eAPD) array. This NIR PyWFS will improve MAPS's sky coverage by an order of magnitude by allowing redder guide stars (e.g. K & M-dwarfs or highly obscured stars in the Galactic plane) to be used. To date, the custom designed cryogenic SAPHIRA camera has been fully characterized and can reach sub-electron read noise at high avalanche gain. In order to test the performance of the camera in a closed-loop environment prior to delivery to the observatory, an AO testbed was designed and constructed. In addition to testing the SAPHIRA's performance, the testbed will be used to test and further develop the proposed on-sky calibration procedure for MMTO's ASM. We will report on the anticipated performance improvements from our NIR PyWFS, the SAPHIRA's closed-loop performance on our testbed, and the status of our ASM calibration procedure., SPIE Proceedings, Astronomical Telescopes and Instrumentation, July 2022, 10 pages, 8 figures

The Gemini North Adaptive Optics (GNAO) facility is the upcoming AO facility for Gemini North providing a state-of-the-art AO system for surveys and time domain science in the era of JWST and Rubin operations. GNAO will be optimized to feed the Gemini infrared Multi Object Spectrograph (GIRMOS). While GIRMOS is the primary science driver for defining the capabilities of GNAO, any instrument operating with an f/32 beam can be deployed using GNAO. The GNAO project includes the development of a new laser guide star facility which will consist of four side-launched laser beams supporting the two primary AO modes of GNAO: a wide-field mode providing an improved image quality over natural seeing for a 2-arcminute circular field-of-view and a narrow-field mode providing near diffraction-limited performance over a 20x20 arcsecond square field-of-view. The GNAO wide field mode will enable GIRMOS's multi-IFU configuration in which the science beam to each individual IFU will be additionally corrected using multi-object AO within GIRMOS. The GNAO narrow field mode will feed the GIRMOS tiled IFU configuration in which all IFUs are combined into a "super"-IFU in the center of the field. GNAO also includes the development of a new Real Time Controller, a new GNAO Facility System Controller and finally the development of a new AO Bench. We present in this paper an overview of the GNAO facility and provide a status update of each product., SPIE conference 2022 Montreal

This article describes a novel optical tweezer system which utilizes a magnetic fluid deformable mirror (MFDM) with a wavefront sensor (WFS) and controller to produce a curved Bessel beam for manipulating an optically trapped microparticle. The MFDM is proposed to control the wavefront phase of the laser beam since it offers the ability to produce a nearly perfect axicon in reflection. The working principle of the MFDM and its modeling and design processes are introduced. A decentralized control method is presented for the MFDM to generate the desired mirror surface shape, combing an axicon and an adjustable compensation phase profile that transforms the incident beam into a self-accelerating Bessel-like beam with curved trajectory. Using a prototype MFDM, an experimental optical tweezer system is set up to verify this optical micromanipulation method. The experimental results show the effectiveness of the proposed technique for the manipulation of optically trapped microparticles.

Using photonic devices, we developed a new approach to traditional spectroscopy where the spectral cross-correlation with a template spectrum can be done entirely on-device. By creating photonic devices with a carefully designed, modulated transmission spectrum, the cross-correlation can be carried out optically without requiring any dispersion, vastly simplifying the instrument and reducing its cost. The measured correlation lag can be used for detecting atomic/molecular species within and determining the radial velocity of a particular astrophysical object. We present an overview of two design approaches that are currently being developed that use different photonic platforms: silicon and fibre-based photonics. The silicon photonic approach utilizes ring resonators that can be thermo-optically modulated to carry out the cross-correlation. The fibre approach uses customized fibre Bragg gratings (FBGs) with transmission spectra that can be strain-modulated. Both approaches have been able to detect molecular gas in a lab setting, and we are now in the process of on-sky testing. Lastly, we discuss the future for these types of devices as their simplicity opens up the possibility of developing low-cost, purpose-built multi-object or integral field spectroscopic instruments that could make significant contributions to scientific programs requiring stellar RV measurements and exoplanet detections., Comment: SPIE Proceedings, Astronomical Telescopes and Instrumentation, July 2022, 10 pages, 7 figures

We present a novel, to the best of our knowledge, remote gas detection and identification technique based on correlation spectroscopy with a piezoelectric tunable fiber-optic Fabry–Perot filter. We show that the spectral correlation amplitude between the filter transmission window and gas absorption features is related to the gas absorption optical depth, and that different gases can be distinguished from one another using their correlation signal phase. Using a previously captured telluric-corrected high-resolution near-infrared spectrum of Venus, we show that the radial velocity of Venus can be extracted from the phase of higher order harmonic lock-in signals. This correlation spectroscopy technique has applications in the detection and radial velocity determination of weak spectral features in astronomy and remote sensing. We experimentally demonstrate a remote C O 2 detection system using a lock-in amplifier, fiber-optic Fabry–Perot filter, and single channel avalanche photodiode.

The absorption spectra of distant targets can be used for remote gas detection. However, the detection of very faint absorption features is difficult since noise can dominate the molecular signal in the acquired spectrum. Rather than using typical dispersive spectroscopy, high sensitivity remote gas sensing is possible by correlation spectroscopy using a spectral matching filter. In this work, we use a thermo-optically tunable nanophotonic silicon waveguide ring resonator as an integrated spectral filter to obtain a correlation signal proportional to the absorption spectrum of a specific gas. We demonstrate the ability to resolve very small absorption depth changes using integrated photonics at the level required for the characterization of exoplanet atmospheres during transits of their host stars., 2021 Photonics North (PN), May 31 - June 2, 2021, Toronto, ON, Canada

Femtosecond laser light has been shaped with a spatial light modulator (SLM) to generate optically thin, aberration-free sheets of uniform intensity for inscription of fiber Bragg gratings (FBGs) inside the core of SMF-28 telecommunication fiber. The combination of flexible beam shaping and sheet-by-sheet writing offers facile means in controlling the coupling to cladding or radiation modes while facilitating spectral tuning flexibility that is not available with interference-based techniques. Spectral responses of uniform first order FBGs fabricated with single-pulse exposures are presented.

Predictive wavefront control is an important and rapidly developing field of adaptive optics (AO). Through the prediction of future wavefront effects, the inherent AO system servo-lag caused by the measurement, computation, and application of the wavefront correction can be significantly mitigated. This lag can impact the final delivered science image, including reduced strehl and contrast, and inhibits our ability to reliably use faint guidestars. We summarize here a novel method for training deep neural networks for predictive control based on an adversarial prior. Unlike previous methods in the literature, which have shown results based on previously generated data or for open-loop systems, we demonstrate our network's performance simulated in closed loop. Our models are able to both reduce effects induced by servo-lag and push the faint end of reliable control with natural guidestars, improving K-band Strehl performance compared to classical methods by over 55% for 16th magnitude guide stars on an 8-meter telescope. We further show that LSTM based approaches may be better suited in high-contrast scenarios where servo-lag error is most pronounced, while traditional feed forward models are better suited for high noise scenarios. Finally, we discuss future strategies for implementing our system in real-time and on astronomical telescope systems., Comment: 11 pages, 14 figures, Accepted to MNRAS

We present our development of the Multi-Object Adaptive Optics (MOAO) system for the Gemini Infra-Red Multi-Object Spectrograph (GIRMOS). The GIRMOS MOAO system consists of four identical arms patrolling over a large field-ofregard (2 arcmin) and able to deliver an image quality close to the diffraction-limit in the near-infrared. The AO system of GIRMOS will performed MOAO correction on top of the wavefront delivered by the Gemini North AO (GNAO) system. We are currently prototyping one arm in the laboratory in order to validate the simulated performances and characterize the hardware as well as different MOAO control strategies. GIRMOS MOAO is a complex AO system and a complete lab characterization would require a full GNAO simulator with a pick-off system and multiple wavefront sensors (WFS), light sources, etc. To circumvent the cost and complexity of such a system we are using a spatial light modulator (SLM) allowing the generation of residual turbulences in specific directions in the field without the need of pick-off system. Coupled with a numerical end-to-end model of the system, our bench is focused on open-loop control rather than tomography. In this paper, we review the GIRMOS MOAO preliminary design of the system, the baseline performances and the status of the testbed.

We are upgrading and refurbishing the first-generation adaptive-secondary mirror (ASM)-based AO system on the 6.5-m MMT in Arizona, in an NSF MSIP-funded program that will create a unique facility specialized for exoplanet characterization. This update includes a third-generation ASM with embedded electronics for low power consumption, two pyramid wavefront sensors (optical and near-IR), and an upgraded ARIES science camera for high-resolution spectroscopy (HRS) from 1-5 μm and MMT-POL science camera for sensitive polarization mapping. Digital electronics have been incorporated into each of the 336 actuators, simplifying hub-level electronics and reducing the total power to 300 W, down from 1800 W in the legacy system — reducing cooling requirements from active coolant to passive ambient cooling. An improved internal control law allows for electronic damping and a faster response. The dual pyramid wavefront sensors allow for a choice between optical or IR wavefront sensing depending on guide star magnitude, color, and extinction. The HRS upgrade to ARIES enables crosscorrelation of molecular templates to extract atmospheric parameters of exoplanets. The combination of these upgrades creates a workhorse instrument for exoplanet characterization via AO and HRS to separate planets from their host stars, with broad wavelength coverage and polarization to probe a range of molecular species in exoplanet atmospheres., SPIE Astronomical Telescopes + Instrumentation, December 14-18, 2020, Online Only, United States, Series: Proceedings of SPIE

GIRMOS is a multi-object adaptive optics spectrograph in the near-infrared currently being designed for the Gemini North telescope. It will allow to observe with high-quality adaptive optics correction multiple targets selected from a large field. To increase the efficiency of the nightly observations, it is important to provide a feedback in real time to operators and observers on the quality of the point-spread function, using intuitive metrics such as the full width at half maximum, the Strehl ratio and the encircled energy. We present a set of simple analytical expressions derived from other works that use the measurement of the wavefront residuals. We then compare the results to an end-to-end AO simulation of GIRMOS. We show that this approach works well with the estimation of the full width at half maximum and the Strehl ratio, while it is less successful with the encircled energy.

Residual phasing errors from segmented mirror telescopes can significantly inhibit the performance of an adaptive optics (AO) system. One approach to quantify these errors utilizes the imaging capabilities of a telescope’s instrument suite; quantification requires images that have observed the primary, therefore these images should be on-sky and AO-corrected in the absence of a source that views the primary. An image-based phase estimation technique that can potentially make this quantification is Phase Diversity, whereby focussed/defocussed images of a bright star are compared with models to estimate phase. Traditional use of this technique with on-sky images can be difficult due to atmospheric evolution between image pairs. This is further compounded due to both NCPA and the partial AO correction of phasing errors persisting in on-sky images. Here we propose a technique that can mitigate the atmospheric effects, estimate the NCPA and assess phasing errors under partial AO correction.

The Gemini Infrared Multi-Object Spectrograph (GIRMOS) is a four-channel adaptive-optics-assisted integralfield spectrograph being designed for the Gemini 8-meter telescopes. Deployed behind the Gemini-North Adaptive Optics (GNAO) system, it will provide spatially-resolved spectra over the 0.9-2.4 um wavelength range for four fields simultaneously. Its multi-object adaptive optics will provide additional correction of the target fields, beyond that achieved by the GNAO system, enabling integral-field spectroscopy with near-diffraction-limited resolution and unprecedented sensitivity. A parallel imaging channel will view the field of regard and provide a simultaneous imaging capability. The primary science objectives include mapping chemical abundances, star formation and kinematics in high-redshift galaxies, and studies of stellar populations, star formation and supermassive black holes in nearby galaxies. In order to support the science programs, GIRMOS requires a system that enables photometric, spectroscopic and astrometric calibration. The GIRMOS Calibration System (CAL) serves this purpose, uniformly illuminating the spectroscopic and imaging channels with both continuous and narrow-line light for flat-field and wavelength calibration. In order to replicate the light path through the instrument as closely as possible, the CAL optical system matches both the pupil position and the focal ratio of the beam delivered to the instrument by GNAO. CAL also includes a metrology system, employing focal-plane masks, to permit precise calibration of the positions of the pick-off arms of the object selection system, and to map optical distortion and instrument flexure. This paper summarizes the key requirements of the CAL system, presents its conceptual design and discusses its expected performance., Ground-based and Airborne Instrumentation for Astronomy VIII, December 14-18, 2020, Online Only, United States, Series: Proceedings of SPIE

The Gemini Infra-Red Multi-Object Spectrograph (GIRMOS) is a four-arm, Multi-Object Adaptive Optics (MOAO) IFU spectrograph being built for Gemini (commissioning in 2024). GIRMOS is being planned to interface with the new Gemini-North Adaptive Optics (GNAO) system, and is base lined with a requirement of 50% EE within a 0.100 spaxel at H-band. We present a design and forecast the error budget and performance of GIRMOS-MOAO working behind GNAO. The MOAO system will patrol the 20 field of regard of GNAO, utilizing closed loop GLAO or MCAO for lower order correction. GIRMOS MOAA will perform tomographic reconstruction of the turbulence using the GNAO WFS, and utilize order 16x16 actuator DMs operating in open loop to perform an additional correction from the Pseudo Open Loop (POL) slopes, achieving close to diffraction limited performance from the combined GNAO+MOAO correction. This high performance AO spectrograph will have the broadest impact in the study of the formation and evolution of galaxies, but will also have broad reach in fields such as star and planet formation within our Milky Way and supermassive black holes in nearby galaxies.

We discuss the preliminary end-to-end optical design of an infrared multi-object integral-field spectrograph (GIRMOS) that is designed to take advantage of the multi-object adaptive optics corrected field at the Gemini telescope. GIRMOS’s optical design consists of object selection pick-offs, an adaptive optics (AO) system, and four identical Integral-Field Spectrographs (IFSes), which employ an image slicer to arrange the integral field along a slit. Each IFS can pick off the individual FOV of 1.0x1.0”, 2.0x2.0”, 4.0x4.0” over a 2’ diameter field-of-regard, at a spatial sampling of 25mas, 50mas, and 100mas, respectively. The pick-offs can also be configured in close-packed arrangement to image a single field. Spectral resolutions of R~3000 and 8000 are available in Y, J, H, and K-bands from 0.95 to 2.4μm.

In this paper we discuss the mechanical design of the GIRMOS Cryostat. GIRMOS is an adaptive optics fed multi-object Integral-Field Spectrograph with a parallel imaging capability and will be installed at the Gemini North Observatory. This instrument includes four separate identical spectrograph channels arranged symmetrically around the central axis of the instrument which provide it its multiplexing capability. Each spectrograph channel starts off at the object selection mechanism. The object selection mechanism contains four motorized fold mirror assemblies which scan the incoming light from the telescope to look at four separate objects simultaneously or combine their efforts to look at a single object in a tiled mode. Each of the four individual beams from the object selection system are then directed into the instrument dewar via separate entrance windows. Within the dewar each IFS beam moves through an anamorphic relay, an optical image slicer assembly and eventually makes it to a Spectrograph unit. All of these assemblies are located on a single cold bench within the dewar. The instrument imager is located along the central axis of the dewar and is housed in the cold bench as well. In this paper we will provide some details regarding the Cryostat design, the mechanical packaging of the IFS and imager along with some of the thermal load mitigation techniques employed. We will also discuss some key performance requirements that were expected from the Cryostat and the design choices we made in order to achieve them.

Systems engineering as a discipline is relatively new in the ground-based astronomy community and is becoming more common as projects become larger, more complex and more geographically diverse. Space and defense industry projects have been using systems engineering for much longer, however those projects don’t necessarily map well onto groundbased astronomy projects, for various reasons. Fortunately, many of the processes and tools have been documented by INCOSE, NASA, SEBoK and other organizations, however there can be incomplete or conflicting definitions within the process and implementation is not always clear. For ground-based systems engineers, adopting these existing processes can be confusing. One area of particular uncertainty involves how, when and where to document operations concepts in a way that captures astronomers’ needs, translates them into concise and complete requirements without over-constraining the design teams or over-burdening the project with complex requirements and document management procedures. We present the criteria and outcome of the solution(s) chosen from the perspective of two different projects: a new observatory that is planning its operations (Maunakea Spectrocopic Explorer, MSE) and a new instrument at a longestablished observatory (Gemini - GIRMOS). Quite possibly, this will not answer the question in the title and may raise more questions. We welcome that discussion., Modeling, Systems Engineering, and Project Management for Astronomy IX, December 14-18, 2020-, Online Only, United States, Series: Proceedings of SPIE

Absorption spectroscopy is widely used in sensing and astronomy to understand molecular compositions on microscopic to cosmological scales. However, typical dispersive spectroscopic techniques require multichannel detection, fundamentally limiting the ability to detect extremely weak signals when compared to direct photometric methods. We report the realization of direct spectral molecular detection using a silicon nanophotonic waveguide resonator, obviating dispersive spectral acquisition. We use a thermally tunable silicon ring resonator with a transmission spectrum matched and cross-correlated to the quasi-periodic vibronic absorption lines of hydrogen cyanide. We show that the correlation peak amplitude is proportional to the number of overlapping ring resonances and gas lines, and that molecular specificity is obtained from the phase of the correlation signal in a single detection channel. Our results demonstrate on-chip correlation spectroscopy that is less restricted by the signal-to-noise penalty of other spectroscopic approaches, enabling the detection of faint spectral signatures.

We present an integrated photonic correlation filter for the detection of remote HCN gas. We demonstrate sensing of absorption due to HCN using thermo-optic tuning of the drop port transmission spectrum in a silicon waveguide ring resonator., 2020 IEEE Photonics Conference (IPC), September 28 - October 1, 2020, Vancouver, BC, Canada

We present the design of integrated astrophotonic instruments for high background atmospheric gas detection. Such instruments can be fibre-coupled to long focal length space telescopes as compact, flexure-free, instruments., Conference on Lasers and Electro-Optics/Pacific Rim 2020, August 3-5, 2020, Sydney Australia

Absorption spectroscopy is a powerful technique for characterizing remote gas composition where direct interaction with a target it not possible. While dispersive spectroscopy is typically used to acquire a spectrum with which the gas presence is determined, correlation spectroscopy can directly detect such spectral features in a single detection channel. Here we present a novel integrated photonics correlation technique on an integrated photonic platform which uses real-time spectral processing to generate a multiline gas specific detection signal., 2020 Photonics North (PN), May 26-28, 2020, Niagara Falls, ON, Canada

MAPS, MMT Adaptive optics exoPlanet characterization System, is the upgrade of legacy 6.5m MMT adaptive optics system. It is an NSF MSIP-funded project that includes (i) refurbishing of the MMT Adaptive Secondary Mirror (ASM), (ii) new high sensitive and high spatial order visible and near-infrared pyramid wavefront sensors, and (iii) the upgrade of Arizona Infrared Imager and Echelle Spectrograph (ARIES) and MMT high Precision Imaging Polarimeter (MMTPol) science cameras. This paper will present the design and development of the visible pyramid wavefront sensor. This system consists of an acquisition camera, a fast-steering tip-tilt modulation mirror, a double pyramid, a pupil imaging triplet lens, and a low noise and high-speed frame rate based CCID75 camera. We will report on hardware and software and present the laboratory characterization results of the individual subsystems, and outline the on-sky commissioning plan., Comment: Fixed an author typo. SPIE, Adaptive Optics Systems VII, Proceedings Volume 11448, 114485J, Dec 14, 2020, See, https://doi.org/10.1117/12.2576353

We present the first high-resolution map of the cold molecular gas distribution, as traced by CO(2-1) emission with ALMA, in a prominent ram pressure stripped tail. The Norma cluster galaxy ESO 137-001 is undergoing a strong interaction with the surrounding intra-cluster medium and is one of the nearest jellyfish galaxies with a long multi-phase tail. We have mapped the full extent of the tail at 1" (350 pc) angular resolution and found a rich distribution of mostly compact CO regions extending to nearly 60 kpc in length and 25 kpc in width. In total about 10^9 M_sun of molecular gas was detected. The CO features are found predominantly at the heads of numerous small-scale (~ 1.5 kpc) fireballs (i.e., star-forming clouds with linear streams of young stars extending toward the galaxy) but also of large-scale (~ 8 kpc) super-fireballs, and double-sided fireballs that have additional diffuse ionized gas tails extending in the direction opposite to the stellar tails. The new data help to shed light on the origin of the molecular tail - CO filaments oriented in the direction of the tail with only diffuse associated Halpha emission are likely young molecular features formed in situ, whereas other large CO features tilted with respect to the tail may have originated from the densest gas complexes that were pushed gradually away from the disk. The ALMA observations of ESO 137-001, together with observations from HST, Chandra and VLT/MUSE, offer the most complete view of a spectacular ram pressure stripped tail to date., Comment: submitted to ApJ (1. revision)

International audience; Gemini Observatory plans to revitalize its AO facility at Gemini North for the benefit of the US and international user community, including a funded MCAO system now in development. Our Strategic Plan calls for the development of a GLAO system enabled by an Adaptive Secondary Mirror. We discuss our plans, progress, and funding outlook.

International audience; Gemini Observatory has been awarded from the National Science Foundation a major fund to build a new state-of-the-art Multi Conjugate Adaptive Optics facility for Gemini North on Maunakea called GNAO. The current Telephone: 1+56 51 2205 642 baseline system will use two lasers each split in two to create an artificial constellation of four laser guide star to measure the distortions caused by the atmosphere. At least two deformable mirror conjugated to 0km and the main altitude layer above Maunakea will be used to correct these distortions. The facility will be designed to feed future instrumentation, initially a near infrared imager and potentially a visiting 4-arm multi object adaptive optics IFU spectrograph. 1 In this paper I will present the main characteristics of this exciting facility, its promises and its challenges. I will also present its conceptual design and results of trade studies conducted within the team and the Gemini Adaptive Optics Working Group. The expected first light is for October 2024.

We present a correlation spectrometer using a silicon waveguide ring resonator for the identification of molecules in stellar and planetary atmospheres. We tailor the free spectral range of a ring resonator to the vibronic overtones of carbon dioxide in the near infrared. The ring resonator spectrum is modulated via the thermo-optic effect and produces a detection signal unique to carbon dioxide. This spectrometer can be used for real-time remote gas detection and radial velocities of exoplanets in a narrow spectral band., 2019 Photonics North (PN), May 21-23, 2019, Quebec City, QC, Canada

Using integral field spectroscopy, we demonstrate that gravity-sensitive absorption features in the zJ-band (0.9--1.35 \micron) can constrain the low-mass stellar initial mass function (IMF) in the cores of two elliptical galaxies, M85 and M87. Compared to the visible bands, the near-infrared (NIR) is more sensitive to light from low-mass dwarf stars, whose relative importance is the primary subject of the debate over IMF variations in nearby galaxies. Our analysis compares the observed spectra to the latest stellar population synthesis models by employing two different methods: equivalent widths and spectral fitting. We find that the IMF slopes in M85 are similar to the canonical Milky Way IMF with a median IMF-mismatch parameter $\alpha_{K} = 1.26$. In contrast, we find that the IMF in M87 is steeper than a Salpeter IMF with $\alpha_{K} = 2.77$. The derived stellar population parameters, including the IMF slopes, are consistent with those from recent results in the visible bands based on spectroscopic and kinematic techniques. Certain elemental abundances, e.g. Na and Fe, have dramatic effects on the IMF-sensitive features and therefore the derived IMF slopes. We show evidence for a high [Na/H] $\sim$ 0.65 dex in the core of M85 from two independent \ion{Na}{1} absorption features. The high Na abundance may be the result of a recent galactic merger involving M85. This suggests that including [Na/H] in the stellar population model parameters is critical for constraining the IMF slopes in M85. These results confirm the viability of using NIR absorption features to investigate IMF variation in nearby galaxies., Comment: 19 pages, 9 figures, Accepted for publication in ApJ

Environmental effects are crucial to the understanding of the evolution of galaxies in dense environments, such as galaxy clusters. Using the large field-of-view of SITELLE, the unique imaging fourier transform spectrograph at CFHT, we are able to obtain 2D spectral information for a large and complete sample of cluster galaxies out to the infall region. We describe a pipeline developed to identify emission line galaxies (ELGs) from the datacube using cross-correlation techniques. We present results based on the spatial offsets between the emission-line regions and stellar continua in ELGs from two z$\sim$0.25 galaxy clusters, Abell 2390 and Abell 2465. We find a preference in the offsets being pointed away from the cluster center. Combining the two clusters, there is a 3$\sigma$ excess for high-velocity galaxies within the virial radius having the offsets to be pointed away from the cluster center. Assuming the offset being a proxy for the velocity vector of a galaxy, as expected from ram pressure stripping, this excess indicates that ram pressure stripping occurs most effectively during the first passage of an infalling galaxy, leading to the quenching of its star formation. We also find that, outside the virial region, the continuum-normalized H$\alpha$ line flux for infalling galaxies with large offsets are on average lower than those with small or no measurable offset, further supporting ram pressure as a dominant quenching mechanism during the initial infall stages., Comment: 25 pages, 18 figures, accepted for publication in ApJ

This paper presents optical night sky brightness measurements from the stratosphere using CCD images taken with the Super-pressure Balloon-borne Imaging Telescope (SuperBIT). The data used for estimating the backgrounds were obtained during three commissioning flights in 2016, 2018, and 2019 at altitudes ranging from 28 km to 34 km above sea level. For a valid comparison of the brightness measurements from the stratosphere with measurements from mountain-top ground-based observatories (taken at zenith on the darkest moonless night at high Galactic and high ecliptic latitudes), the stratospheric brightness levels were zodiacal light and diffuse Galactic light subtracted, and the airglow brightness was projected to zenith. The stratospheric brightness was measured around 5.5 hours, 3 hours, and 2 hours before the local sunrise time in 2016, 2018, and 2019 respectively. The $B$, $V$, $R$, and $I$ brightness levels in 2016 were 2.7, 1.0, 1.1, and 0.6 mag arcsec$^{-2}$ darker than the darkest ground-based measurements. The $B$, $V$, and $R$ brightness levels in 2018 were 1.3, 1.0, and 1.3 mag arcsec$^{-2}$ darker than the darkest ground-based measurements. The $U$ and $I$ brightness levels in 2019 were 0.1 mag arcsec$^{-2}$ brighter than the darkest ground-based measurements, whereas the $B$ and $V$ brightness levels were 0.8 and 0.6 mag arcsec$^{-2}$ darker than the darkest ground-based measurements. The lower sky brightness levels, stable photometry, and lower atmospheric absorption make stratospheric observations from a balloon-borne platform a unique tool for astronomy. We plan to continue this work in a future mid-latitude long duration balloon flight with SuperBIT., Comment: 17 pages, 7 figures. Accepted for publication in the Astronomical Journal

We report the optical design of an infrared (0.85-1.8 μm) pyramid wavefront sensor (IRPWFS) that is designed for the 6.5m MMT on telescope adaptive optics system using the latest developments in low-noise infrared avalanche photodiode arrays. The comparison between the pyramid and the double-roof prism based wavefront sensors and the evaluation of their micro pupils’ quality are presented. According to our analysis, the use of two double-roof prisms with achromatic materials produces the competitive performance when compared to the traditional pyramid prism, which is difficult to manufacture. The final micro pupils on the image plane have the residual errors of pupil position, chromatism, and distortion within 1/10 pixel over the 2×2 arcsecond field of view, which meet the original design goals., Series: Proceedings of SPIE; no. 10401