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Kinematics of Nearby Active Galactic Nucleus Host Ngc 7582 KINEMATICS OF NEARBY ACTIVE GALACTIC NUCLEUS HOST NGC 7582 Item Type Electronic Thesis; text Authors Walla, Emily Citation Walla, Emily. (2020). KINEMATICS OF NEARBY ACTIVE GALACTIC NUCLEUS HOST NGC 7582 (Bachelor's thesis, University of Arizona, Tucson, USA). Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 07/10/2021 08:31:34 Item License http://rightsstatements.org/vocab/InC/1.0/ Link to Item http://hdl.handle.net/10150/651409 KINEMATICS OF NEARBY ACTIVE GALACTIC NUCLEUS HOST NGC 7582 By EMILY CATHERINE WALLA ____________________ A Thesis Submitted to The Honors College In Partial Fulfillment of the Bachelor’s degree With Honors in Astronomy THE UNIVERSITY OF ARIZONA MAY 2020 Approved by: ______________________ Dr. Stephanie Juneau NSF National Optical-Infrared Astronomy Research Lab, The Astro Data Lab Dr. Susan Ridgway, NSF National Optical-Infrared Astronomy Research Laboratory, served as a secondary advisor for this project. She provided extensive scientific background for the project. Madison Walder, undergraduate student in the University of Arizona Class of Spring 2020, worked on a project adjacent to mine and as such, provided some small modifications to the code eventually used to complete my project. Leah Fulmer, PhD candidate at the University of Washington, worked with Stephanie Juneau before me and completed some initial analyses and wrote code that was foundational in the first year of the project but was ultimately not implemented in the project’s final form. Building off of Leah’s work has made me better at the python computer language, and their contribution to this project should be recognized. Draft version May 9, 2020 Typeset using LATEX default style in AASTeX63 Kinematics of Nearby Active Galactic Nucleus Host NGC 7582 Emily Walla,1 Stephanie Juneau,2 Susan Ridgway,2 Madison Walder,1 and Leah Fulmer3 1University of Arizona Department of Astronomy and Steward Observatory 2NSF National Optical-Infrared Astronomy Research Laboratory 3University of Washingtom Department of Astronomy (Received May 6, 2020; Accepted May 9, 2020) Submitted to AJ ABSTRACT High-quality, spatially-resolved spectroscopy from the MUSE instrument on the Very Large Telescope allows for the exploration of the chemical composition and kinematics of stars and gas around Active Galactic Nuclei (AGN). The Galaxy IFU Spectroscopy Tool (GIST) performs kinematic fitting of the MUSE Data, opening the door for analysis of outflows, inflows and structure of active galaxies. We present an analysis, by applying the GIST Pipeline to MUSE IFU data, of the nearby active galaxy NGC 7582. In the star and gas kinematics, we find signatures of a large-scale bar. We report on neutral gas kinematics for the first time, finding tentative evidence for large-scale outflows outside the outflowing ionized gas cones. Furthermore, we confirm the presence of a recently-found kinematically distinct core comprised of a ring of fast-moving stars approximately 600 pc in diameter. Our study emphasizes the need to account for galaxy substructure and different phases of the interstellar medium while continuing to improve our understanding of the connection between AGN and their host galaxies. Keywords: AGN, galaxy evolution, interstellar medium, neutral gas outflow, ionized gas outflows, galaxy structure, spiral galaxy 1. INTRODUCTION Active galactic nuclei (AGN) are supermassive black holes at the center of their host galaxies that are actively accret- ing material and feeding outflows of matter from the galaxy. Through this process of accretion and expulsion, feedback can suppress star formation in some regions of the galaxy while possibly exciting it in others (Cresci et al. 2015). How- ever, the effect AGN have on the long-term evolution of their host galaxy and the role they play in transitioning galaxies from gas-rich with ample star formation to gas-poor with few stellar births are not well understood. Improving the understanding of the AGN-host galaxy relationship requires high-quality observations taken over a wide wavelength range in order to paint the most complete picture possible of the components and kinematics of active galaxies. Itegral-field spectroscopy done by the Multi-Unit Spectroscopic Explorer (MUSE) instrument on the European Southern Observatory's Very Large Telescope provides approximately 90,000 spatially resolved spectra, allowing for a detailed analysis of the kinematics of gas and stars (Bacon et al. 2010). Furthermore, the MUSE instrument's wide field of view allows for this kinematic analysis to be done on a kpc scale. Large-scale mapping is vital to understanding the relationship between AGN and their host galaxies, as AGN-ionized regions and outflows often span kpc, and inflows and large-scale structures in the galaxy may not be captured in narrow fields of view. To gain more physical insight on the AGN-host galaxy connection, we conduct a detailed case study of an intriguing active galaxy that has previously showed hints of a relationship between the AGN and the large-scale host galaxy structure. NGC 7582 is a nearby (z = 0:005 (de Vaucouleurs et al. 1991)) galaxy housing a supermassive black hole of 7 mass 5:5 ∗ 10 M which fuels its active nucleus. The AGN of NGC 7582 is Compton thick and the broad line region is obscured optically. With a disk inclined 65 degrees, the galaxy has significant line-of-sight velocities, allowing for the analysis of rotational, radial and other motions of its components. A MUSE datacube containing information on right ascension, declination, and wavelength was collected in 2015 in ESO program 095.A-0934 (PI Juneau). This datacube 2 Walla et al. is centered on the optical galactic nucleus and covers 64 sq kpc at the distance of NGC 7582: approximately 22.5 Mpc (Tully et al. 2013). 2. METHODS Previous work on this data revealed a flattened kinematically distinct core of fast-moving stars. This ring or disk of stars is approximately 600 pc in diameter, and is centered on the galactic nucleus, which serves to collimate biconical outflows of ionized gas (Prieto et al. 2014, Juneau et al., submitted, hereafter J20). We confirm the presence of this kinematically distinct core and include visualization of the higher-order Gauss-Hermite moments of the stellar kinematics. Furthermore, we present signatures of a large-scale bar in the ionized gas, and we find clear indications of distinct kinematics of the neutral interstellar medium (ISM) traced by the Na D absorption lines; this could be due to differential motion, misaligned rotation, neutral gas outflows or a combination of these. The data used in this analysis were collected through ESO program 095.A-0934 (PI Juneau). With dimensions in right ascension and declination and a third dimension in wavelength, the spectral pixels, or "spaxels" compose a 3-dimensional dataset. The datacube's wavelength range is 4750A˚ to 9352A,˚ with a step size of 1.25A,˚ yielding 3682 spectral datapoints per spatial coordinate, and each side of the datacube covers 1' of sky, or approximately 8kpc at the distance to NGC 7582. The datacube was spectrally trimmed to span 4750A˚ to 8900A˚ using the muse python data analysis framework (MPDAF) (Bacon et al. 2016), and this spectrally trimmed datacube was used for analysis. A white light image, created by summing the flux across the entire spectrum in each spaxel using the MPDAF package, is shown in Fig1. Analysis of the reduced datacube be- gan with the GIST pipeline (Bittner et al. 2019a). The pipeline first creates Voronoi Bins of the datacube (Cappel- lari & Copin 2003), such that the spec- tra across all bins have constant or near- constant signal-to-noise ratios, a param- eter determined by the GIST user. The pipeline then performs penalized pixel fitting (pPXF) (Cappellari 2017) of the binned spectra to fit the stellar contin- uum. This fit yields line-of-sight ve- locity distribution in the galaxy's rest frame, allowing for the user to analyze the line-of-sight velocity, velocity dispe- rion, skewness of the velocity, and kurto- sis of the dispersion. Then, GIST performs an analysis of select emission and absorption lines us- ing the GANDALF module(Sarzi et al. 2017), which treats each emission or ab- sorption line input to the pipeline as Figure 1. White light image NGC 7582, created by summing the flux over a Gaussian template, and by combin- each spaxel f the MUSE datacube using the MPDAF package. Each side measures 8kpc, centered on the optical galactic nucleus. The blue, green, and ing the given templates with those from red stars in the Southeast, center and Northwest of the galaxy correspond to an input spectral template library, GIST the respectively colored spectra in Figs2 and6 finds and stores the kinematic informa- tion { velocity and velocity dispersion { . and the flux and amplitude of the emis- sion and absorption lines (Sarzi et al. 2006). A full description of the GIST pipeline's capabilities can be found in the work by Bittner and colleagues, and in the online documentation (Bittner et al. 2019b). We selected a target signal-to-noise ratio of 50 and a minimum signal-to-noise ratio of 3 for the Voronoi binning step of the GIST pipeline. Any bins that could not meet the minimum SNR were excluded from the analysis and not plotted, while individual spaxels that met or exceeded the target SNR were left as individual spaxels and not included NGC7582 Kinematics 3 in larger bins. E-MILES, the Extended MILES stellar population models Vazdekis et al.(2016), served as our input library of spectral templates for the pPXF module of the GIST pipeline.
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