CCD Photometric Observations of Active Galactic Nuclei and their Neighbours by Traianou Efthalia A dissertation submitted in partial fulfillment of the requirements for the degree of Ptychion (Physics) in Aristotle University of Thessaloniki September 2016 Supervisor: Manolis Plionis, Professor To my loved ones Many thanks to: Manolis Plionis for accepting to be my thesis adviser. ii TABLE OF CONTENTS DEDICATION :::::::::::::::::::::::::::::::::: ii LIST OF FIGURES ::::::::::::::::::::::::::::::: v LIST OF TABLES :::::::::::::::::::::::::::::::: ix LIST OF APPENDICES :::::::::::::::::::::::::::: x ABSTRACT ::::::::::::::::::::::::::::::::::: xi CHAPTER I. Introduction .............................. 1 II. Active Galactic Nuclei ........................ 4 2.1 Early History of AGN’s ..................... 4 2.2 AGN Phenomenology ...................... 7 2.2.1 Seyfert Galaxies ................... 7 2.2.2 Low Ionization Nuclear Emission-Line Regions(LINERS) 10 2.2.3 ULIRGS ........................ 11 2.2.4 Radio Galaxies .................... 12 2.2.5 Quasars or QSO’s ................... 14 2.2.6 Blazars ......................... 15 2.3 The Unification Paradigm .................... 16 2.4 Beyond the Unified Model ................... 18 III. Research Goal and Methodology ................. 21 3.1 Torus ............................... 21 3.2 Ha Balmer Line ......................... 23 3.3 Galaxy-Galaxy Interactions ................... 25 3.4 Our Aim ............................. 27 iii IV. Observations .............................. 29 4.1 The Telescope .......................... 29 4.2 Instrumentation ......................... 30 4.3 Preparation and Observations ................. 31 4.3.1 Observations ..................... 33 V. Data Analysis ............................. 35 5.1 Background ........................... 35 5.2 Data Reduction ......................... 37 5.2.1 Dark Noise ...................... 37 5.2.2 Bias Subtraction ................... 37 5.2.3 Flat Field Correction ................. 38 5.2.4 Fixing the Problems ................. 40 5.2.5 Cosmic Rays Cleaning ................ 40 5.2.6 Galaxy Extinction .................. 41 5.2.7 AB Magnitude .................... 41 5.3 Airmass .............................. 44 5.4 Standard Stars .......................... 45 5.5 Photometry ........................... 48 5.5.1 Aperture Photometry ................. 48 5.5.2 Surface Photometry .................. 50 VI. Results and Conclusions ....................... 51 6.1 Comparison with the bibliography ............... 51 6.2 Photometry between AGN and neighbours .......... 53 6.2.1 Individual “Blob” Photometry ............ 66 6.2.2 NGC 7469 ....................... 73 APPENDICES :::::::::::::::::::::::::::::::::: 75 BIBLIOGRAPHY :::::::::::::::::::::::::::::::: 85 iv LIST OF FIGURES Figure 2.1 Right:A multiwavelength view of the Cygnus A radio-galaxy as cap- tured by Hubble telescope. Image Credit: NASA, ESA, S. Baum and C. O’Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA) . Left:An image montage in optical frequencies of the distant quasar 3C 273. Image Credit: NASA and J. Bahcall (IAS). ..................... 6 2.2 In this BPT diagram we see the spread of emission-line galaxies from the Sloan Digital Sky Survey (SDSS). This diagram uses 4 strong optical emission lines, [OIII] 5007, [NII] 6583, Ha 6563, and Hb 4861, in order to distinguish galaxies that are dominated by ionization from young stars (green dots, labelled as ”Star-forming Galaxies”), from those that are ionized by an accreting SMBH in their center (Seyfert and LINER galaxies). The solid curve indicates the empirical dividing lines and the dased the theoretical between active galactic nuclei and star-forming (SF) galaxies, based upon the SDSS spectroscopic observations (Kauffmann et al. [46], Kewley and A.Dopita [51]. ... 11 2.3 Stacked 43 GHz image from the radio galaxy Gygnus A, observed with the Global VLBI at 7mm wavelengths. This resolution cor- responds to a linear scale of approximate 400 Schwarzschild radii. (Boccardi et al. [11]) .......................... 13 2.4 This is the spectra of the first quasar in history. As we can see, the emission lines are shifted because of Doppler Effect(∆λ = u/c, where λ is the wavelength of the line and c the speed of light and u ≪ c). 15 2.5 A unified model of AGNs. The upper right part of the drawing cor- responds to high-power sources with the jet emerging from an open torus, the left upper part, represent the low-power sources with the jet emerging from a closed torus. Different morphologies are produced by the orientation of the observer with respect to the obscuring torus. Credit: Beckmann and Shrader [8]. .................. 18 2.6 Simple schematic of galaxy and AGN evolution (Hickox et al. [39]) . 20 v 3.1 A representation of the 2 phase torus (a homogeneous disk or a clumpy medium) and of the host galaxy structure together with the thermal distribution around the central engine (as presented in the work of Siebenmorgen et al. [80]). ................... 22 3.2 Electron transitions of the hydrogen atom and the wavelength of the each emission line that stems from. .................. 24 3.3 Inside the corotation, the gas undergoes negative gravity torques, and looses angular momentum in a rapid central gas inflow towards the central area. In the outer disk, gas would gain angular momentum and fly out to intergalactic space in long tidal tails. ......... 26 4.1 The Aristarchos telescope of the Helmos Observatory. The telescope has a Ritchey-Cretien optical system with a primary mirror of 2.280m in diameter whereas its focal ratio is f/8 and its focal length reaches the 17.714 meters. Photo credits: Theofanis Matsopoulos. ...... 30 4.2 An artistic photograph of the observatory during a rare atmospheric phenomenon (sundog and circumnuclear arc) taken by the author. 33 5.1 An illustration of the collecting procedure of a typical CCD sensor. The photons fill the pixels, which are converted in order to reach the computer as a digital signal. ...................... 36 5.2 Left: A print screen of the adjustments in Aristarchos remote control environment in order to obtain bias. Right: A master bias frame of our observations. ............................ 38 5.3 A snapshot of the CCD cooling procedure using liquid hydrogen in Aristarchos telescope. .......................... 39 5.4 A typical appearance of a master flat. This frame is a combination of 7 frames before our observations and 7 after. We create a master flat for each and every night. ...................... 39 5.5 At left we can see a single ”dirty” image of the NGC 1241 galaxy and its neighbour. At right we can see a combination of three exposures, cleaned from CCD noise and cosmic events. ............. 41 5.6 A schematic representation of the airmass effect. ........... 45 5.7 The mAB absolute magnitude vs wavelenght (Å) for the Feige34 spec- trophotometric standard star. ..................... 46 5.8 The interface of the Aristarchos Telescope Control Gui environment during an standard star exposure. .................. 46 5.9 An examble of the aperture photometry. The inner radius measure the star+backround counts, whereas the annulus the sky contribution. 49 6.1 log(L) of the currrent work versus log(L) of Theios et al. [83]. The diagonal line represents the equality line between the different mea- surements. We can see that there are some differences, but there are several reasons for this. The most crucial are the weather conditions, since we faced problematic photometric atmospheric conditions with heavy cirrus clouds during some of our observation sessions. .... 52 vi 6.2 Left: The Sy2 NGC 3786 and its neighbour NGC 3788. The upper panel shows the SDSS broad-band composite image while the lower panel shows our narrow-band Ha data. ................ 54 6.3 The pair Sy2 NGC 1320. The upper panel shows the SDSS broad- band composite image while the lower panel shows our narrow-band Ha data. ................................. 55 6.4 The pair Sy2 UGC 12138. The upper panel shows the SDSS broad- band composite image while the lower panel shows our narrow-band Ha data. ................................ 56 6.5 Left: The pair Sy2 NGC 1241. The upper panel shows the SDSS broad-band composite image while the lower panel shows our narrow- band Ha data. .............................. 57 6.6 Left: The pair Sy2 IRAS 00160-0719. The upper panel shows the SDSS broad-band composite image while the lower panel shows our narrow-band Ha data. ......................... 58 6.7 Left: The pair Sy2 MRK 612. The upper panel shows the SDSS broad-band composite image while the lower panel shows our narrow- band Ha data. .............................. 59 6.8 Left: The pair Sy2 NGC 7682. The upper panel shows the SDSS broad-band composite image while the lower panel shows our narrow- band Ha data. These object were selected as control sample. .... 60 6.9 Left: The pair Sy1 NGC 863. The upper panel shows the SDSS broad- band composite image while the lower panel shows our narrow-band Ha data. ................................. 61 6.10 Left: The pair Sy1 NGC 1019. The upper panel shows the SDSS broad-band composite image while the lower panel shows our narrow- band Ha data. .............................. 62 6.11 The pair Sy1 NGC 1194. The upper panel shows the SDSS broad- band composite image while the lower panel shows our narrow-band Ha data. ................................. 63 6.12 Ha F luxbetween versus Ha F luxbackground for the Seyfert 1 case. ... 64 6.13 Ha F luxbetween