Institute of Astronomy University of Cambridge Natural Sciences Tripos Part III/MASt Astrophysics Project Booklet Version date: 13th Oct 2014 2014-2015 Editors: Ian Parry and Judith Moss Project List Supervisor(s) Associated UTO Project Title 1 William Alston and Andy Fabian The high-frequency rms-flux relation in accreting black holes Matt Middleton 2 Matt Auger Andy Fabian Active galactic nuclei and their host galaxies: connecting star formation, mass, and AGN activity 3 Mederic Boquien Rob Kennicutt One ring to rule them all: star formation and feedback in the collision debris around NGC 5291 4 Mederic Boquien Rob Kennicutt Star formation in galaxies: observation and modelling of fine structure lines 5 Heather Campbell Gerry Gilmore Searching for progenitors of type Ia Supernovae 6 Thomas de Boer Vasily Belokurov The extended surroundings of the Carina dwarf spheroidal galaxy 7 Ilse De Looze Rob Kennicutt The non--locality of dust heating in galaxies 8 Ilse De Looze Rob Kennicutt Variation in dust properties along the disk of M51 9 Giullio Del-Zanna Giullio Del-Zanna Coronal bright points in the solar atmosphere and Helen Mason and Helen Mason 10 Denis Erkal Vasily Belokurov Using tidal debris to understand galaxy formation 11 Morgan Fraser Gerry Gilmore A survey in between the clouds 12 Morgan Fraser Gerry Gilmore SN 1987A with the Hubble Space Telescope 13 Gerry Gilmore, Gerry Gilmore Local group cosmology with Gaia Floor van Leeuwen and Nic Walton 14 Paula Jofre Gerry Gilmore Gaia benchmark stars: improving stellar physics 15 Paula Jofre Chris Tout Stellar evolution with blue stragglers 16 Grant Kennedy Mark Wyatt Signatures of a multi-planet system around HD 107146 17 Grant Kennedy Mark Wyatt Dynamics of extra-Solar circumplanetary disks 18 Henrik Latter and Henrik Latter Dust dynamics in a turbulent protoplanetary disk Gordon Ogilvie 19 Anne Lohfink and Andy Fabian Exploring the close family of the active galaxy Fairall 9 William Alston 20 Nikku Nikku Effect of solid accretion on atmospheric compositions of giant Madhusudhan and Madhusudhan exoplanets Mark Wyatt 21 Thomas Masseron Gerry Gilmore Constraining the chemistry of the first stars of the Galaxy 22 Thomas Masseron Gerry Gilmore Inferring TiO molecular data for applications to stellar astrophysics and Andy Casey and exoplanets 23 Richard McMahon Richard McMahon Host galaxy properties of active galaxies and quasars in the Dark and Manda Banerji Energy Survey 24 Ben Moster Debora Sijacki The time-scale of galaxy mergers and satellite stripping 25 Ben Moster Debora Sijacki Origin of fast and slow rotators in elliptical galaxies 26 Adam Muzzin Richard McMahon Searching for gravitationally-lensed massive galaxies at high redshift 27 Adam Muzzin Richard McMahon The mass growth and structural evolution of massive galaxies over cosmic time 28 Olja Panic Cathie Clarke Density structure of planet-forming regions 29 Ewald Puchwein Martin Haehnelt The cosmic ultraviolet background and the thermal history of the Universe 30 Giovanni Rosotti Cathie Clarke The effect of stellar encounters on disc size 31 Helen Russell and Andy Fabian The impact of quasar feedback on a host galaxy cluster Stephen Walker 32 Chris Tout and Chris Tout Nucleosynthesis during proton ingestion Anna Zytkow 33 Ranjan Vasudevan Andy Fabian The power output from accretion onto supermassive black holes in and Anne Lohfink active galaxies 34 Nic Walton Mike Irwin Distributions of planetary nebulae in Centaurus A 35 Clare Worley Gerry Gilmore Tracing chemical signatures in asymptotic giant branch stars 36 Mark Wyatt and Mark Wyatt Modelling the accretion of dust onto extrasolar planets Andrew Shannon 37 Anna Zytkow Chris Tout Stars with neutron cores and possible metal enhancement in early galaxies 38 Priscilla Canizares Anthony Lazenby Testing Chern-Simons modified gravity with gravitational-wave and Jonathan Gair detections of relativistic binaries. 39 Chris Tout and Chris Tout Tidal dissipation in stars with deep convective envelopes Anna Zytkow Part-III/MASt Astrophysics Projects 2014-2015 Version date: 13th Oct 2014 Introduction This booklet contains descriptions of the individual projects available in the academic year 2014-2015. Each entry contains a brief description of the background to the project along with a summary of the type of work involved and several references where more information can be obtained. The booklet is made available just before the start of the Michaelmas term to give students about 2 weeks to choose which projects they are interested in. Ian Parry, Part III/MASt Astrophysics Course Coordinator, Michaelmas term 2014 Page 3 of 73 Part-III/MASt Astrophysics Projects 2014-2015 Version date: 13th Oct 2014 The high-frequency rms-flux relation in accreting black holes Supervisors: Will Alston; Office: H56; [email protected] Matt Middleton; Office: H52; [email protected] Andy Fabian; Office: H49; [email protected] Background Active Galactic Nuclei (AGN) are powered by accretion of matter through a disc which extends deep into the gravitational well of a supermassive black hole (SMBH). Accreting black holes show variations over a broad range of timescales, with the X-rays exhibiting the most rapid and large amplitude variability. As the characteristic time scales of variability scale inversely with distance from the black hole, the variations on the shortest time scales are expected to originate from the most inner regions. With an origin in the strongly-curved spacetime close to a black hole, these variations should therefore carry vital information about the two fundamental properties of black holes: mass and spin. The exact origin of the variability processes and the characteristic frequencies remain elusive. We can, however, begin to understand these processes using signal processing techniques. Figure 1a shows a 120 ks example X-ray light curve from a accreting SMBH, where large amplitude and rapid variations can be seen. The variability can be quantified in several ways and a common approach is to compute the power spectral density (PSD) as shown in Figure 1b. This shows the magnitude of the variations as a function of Fourier frequency (1/timescale). The PSD is modelled with two components: a broadband power-law and a Lorentzian. These two components indicate that there is more than one source of variations contributing to the observed light curve; broadband noise and a quasi-periodic oscillation. Another observed variability pattern is the linear rms-flux relation as shown in Fig. 1c. This says that the amplitude of variations increases as the flux (intensity) of the X-ray emission increases. The relation is observed to hold for a range of time scales, indicating that the variations on different timescales are coupled, as would be expected from variations produced at different radii in an accretion disc. However, deviations from the linear rms-flux relation have been reported in one accreting stellar mass black hole (see Fig. 1d). The gradient of the rms-flux relation of the QPO flattens and turns negative as the QPO increases in frequency. Observing this change in the rms-flux relation in an AGN will allow us to understand the variable emission coming from the direct vicinity of a black hole. The project aims are to study the X-ray PSD and rms-flux relation in a small sample (∼ 10 objects) of nearby and highly variable AGN. We will search the high-frequency part of the PSD for QPOs and look for deviations from the expected linear rms-flux relation. These can then be compared to other system properties such as spectral hardness and time-delays. Nature of the project work This is an observational data analysis project involving the use of archival XMM-Newton X-ray data. IDL will the be the main programming language used, as well as the standard Project number 1 Page 4 of 73 Part-III/MASt Astrophysics Projects 2014-2015 Version date: 13th Oct 2014 Figure 1: a (TL): X-ray light curve of an accreting black hole. b (TR): The PSD for the light curve in a, where two variability components are present. c (BL): The linear rms- flux relation observed in accreting compact objects. d (BR): The change in gradient of the rms-flux relation with QPO frequency in an X-ray binary (Heil et al. 2011). X-ray analysis software, XSPEC. This software is easy to use, and example scripts will be provided. An outline of the project is as follows: • Reduction of archival XMM-Newton data to produce spectra and light curves • Using signal processing methods to compute the PSD and rms-flux in different X-ray energy bands • Modelling the PSD in a Bayesian framework and search for QPOs and measure the gradient of the rms-flux relation Useful texts Articles can be found online by searching for author and year at http://adsabs.harvard. edu/abstract_service.html or by following the link to arXiv. • For an overview of the X-ray variability see the review by McHardy (2010, http:// arxiv.org/abs/0909.2579) and Vaughan (2013, http://arxiv.org/abs/1309.6435) • For an overview of the X-ray spectral components in AGN see Fabian (2006, http:// arxiv.org/abs/astro-ph/0511537) and Fabian (2013, http://arxiv.org/abs/1211. 2146). • For a detailed look at the work involved in this project see Alston et al., (2014, http://arxiv.org/abs/1407.7657) or Heil et al., (2011, http://arxiv.org/abs/ 1011.6321) and references therein. Project number 1 Page 5 of 73 Part-III/MASt Astrophysics Projects 2014-2015 Version date: 13th Oct 2014 Active Galactic Nuclei and Their Host Galaxies: Connecting Star Formation, Mass, and AGN Activity Supervisor: Matt Auger, H40, [email protected] Background: The masses of super-massive black holes are tightly correlated with the central stellar velocity dispersions and stellar masses of their host galaxies, possibly signalling a close connection between the growth of these black holes and the galaxies in which they reside.