Publications by Katherine Blundell


Amplification of perpendicular and parallel magnetic fields by cosmic ray currents

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 469 (2017) 1849-1860

JH Matthews, AR Bell, KM Blundell, AT Araudo


Deep 230-470 MHz VLA observations of the mini-halo in the Perseus cluster

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 469 (2017) 3872-3880

M Gendron-Marsolais, J Hlavacek-Larrondo, RJ van Weeren, T Clarke, AC Fabian, HT Intema, GB Taylor, KM Blundell, JS Sanders


Fast launch speeds in radio flares, from a new determination of the intrinsic motions of SS 433's jet bolides

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 461 (2016) 312-320

RM Jeffrey, KM Blundell, SA Trushkin, AJ Mioduszewski


A very deep Chandra view of metals, sloshing and feedback in the Centaurus cluster of galaxies

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP): Policy P - Oxford Open Option A (2016)

KM Blundell


Evidence that the maximum electron energy in hotspots of FR II galaxies is not determined by synchrotron cooling

Monthly Notices of the Royal Astronomical Society (2016) stw1204-stw1204

AT Araudo, AR Bell, A Crilly, KM Blundell


A very deep Chandra view of metals, sloshing and feedback in the Centaurus cluster of galaxies

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 457 (2016) 82-109

JS Sanders, AC Fabian, GB Taylor, HR Russell, KM Blundell, REA Canning, J Hlavacek-Larrondo, SA Walker, CK Grimes


Multiwavelength study of Cygnus A V. The hotspots in the lobe

ASTRONOMY & ASTROPHYSICS 574 (2015) ARTN A30

S Pyrzas, KC Steenbrugge, KM Blundell


PARTICLE ACCELERATION AND MAGNETIC FIELD AMPLIFICATION IN THE JETS OF 4C74.26

ASTROPHYSICAL JOURNAL 806 (2015) ARTN 243

AT Araudo, AR Bell, KM Blundell


Do high-redshift quasars have powerful jets?

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 442 (2014) L81-L84

AC Fabian, SA Walker, A Celotti, G Ghisellini, P Mocz, KM Blundell, RG McMahon


Near infrared extinction at the galactic centre

in Astrophysics and Space Science Proceedings, 37 (2013) 201-206

AJ Gosling, RM Bandyopadhyay, KM Blundell

© Springer Science+Business Media Dordrecht 2013. We present new results from UKIDSS on the Nuclear Bulge of our Galaxy that shows the previous determinations of the extinction parameter need revising.


The X-ray luminous cluster underlying the z = 1.04 quasar PKS1229-021

Monthly Notices of the Royal Astronomical Society 422 (2012) 590-599

HR Russell, AC Fabian, GB Taylor, JS Sanders, KM Blundell, CS Crawford, RM Johnstone, E Belsole

We present a 100ks Chandra observation studying the extended X-ray emission around the powerful z= 1.04 quasar PKS1229-021. The diffuse cluster X-ray emission can be traced out to ∼15arcsec (∼120kpc) radius and there is a drop in the calculated hardness ratio inside the central 5arcsec consistent with the presence of a cool core. Radio observations of the quasar show a strong core and a bright, one-sided jet leading to the south-west hotspot and a second hotspot visible on the counter-jet side. Although the wings of the quasar point spread function (PSF) provided a significant contribution to the total X-ray flux at all radii where the extended cluster emission was detected, we were able to accurately subtract the PSF emission using Chandra Ray Tracer and marx simulations. The resulting steep cluster surface brightness profile for PKS1229-021 appears similar to the profile for the FR II (Fanaroff-Riley class II) radio galaxy 3C444, which has a similarly rapid surface brightness drop caused by a powerful shock surrounding the radio lobes. Using a model surface brightness profile based on 3C444, we estimated the total cluster luminosity for PKS1229-021 to be. We discuss the difficulty of detecting cool-core clusters, which host bright X-ray sources, in high redshift surveys. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.


Concepts in Thermal Physics 2nd Edition

, 2012

SJ Blundell, KM Blundell


Probing the history of SS433's jet kinematics via decade-resolution radio observations of W50

Monthly Notices of the Royal Astronomical Society 414 (2011) 2828-2837

PT Goodall, KM Blundell, SJ Bell Burnell

We present the results of a kinematical study of the W50 nebula using high-resolution radio observations from the Very Large Array spanning a 12-yr period, sampled in 1984, 1993 and 1996. We conduct a careful analysis of the proper motions of the radio filaments across the W50 nebula at each epoch and detect no significant motion for them during this period. The apparent lack of movement in the radio filaments mandates either (i) a high degree of deceleration of SS433's jet ejecta in the W50 nebula; or (ii) that the lobes of W50 formed a long time ago in SS433's history, during a jet outburst with appreciably different characteristics from the well-known precessing jet state observed in SS433 at the present day. We discuss the possible scenarios which could explain this result, with relevance to the nature of SS433's current jet activity. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.


When microquasar jets and supernova collide: Hydrodynamically simulating the SS433-W50 interaction

Monthly Notices of the Royal Astronomical Society 414 (2011) 2838-2859

PT Goodall, F Alouani-Bibi, KM Blundell

We present investigations of the interaction between the relativistic, precessing jets of the microquasar SS433 and the surrounding, expanding supernova remnant (SNR) shell, W50, and the consequent evolution in the inhomogeneous interstellar medium (ISM). We model their evolution using the hydrodynamic flash code, which uses adaptive mesh refinement. We show that the peculiar morphology of the entire nebula can be reproduced to a good approximation, due to the combined effects of (i) the evolution of the SNR shell from the free-expansion phase through the Sedov blast wave in an exponential density profile from the Milky Way disc, and (ii) the subsequent interaction of the relativistic, precessing jets of SS433. Our simulations reveal: (1) Independent measurement of the Galaxy scaleheight and density local to SS433 (as n 0 = 0.2cm -3 ,Z d = 40pc), with this scaleheight being in excellent agreement with the work of Dehnen & Binney. (2) A new mechanism for hydrodynamic refocusing of conical jets. (3) The current jet precession characteristics do not simply extrapolate back to produce the lobes of W50, but a history of episodic jet activity having at least three different outbursts with different precession characteristics would be sufficient to produce the W50 nebula. A history of intermittent episodes of jet activity from SS433 is also suggested in a kinematic study of W50 detailed in a companion paper. (4) An estimate of the age of W50, and equivalently the age of SS433's black hole created during the supernova explosion, in the range of 17000-21000yr. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.


The inverse-Compton ghost HDF130 and the giant radio galaxy 6C0905+3955: Matching an analytic model for double-lobed radio source evolution

Monthly Notices of the Royal Astronomical Society 417 (2011) 1576-1583

P Mocz, AC Fabian, KM Blundell, PT Goodall, SC Chapman, DJ Saikia

We present new Giant Metre-wave Radio Telescope (GMRT) observations of Hubble Deep Field (HDF)130, an inverse-Compton (IC) ghost of a giant radio source that is no longer being powered by jets. We compare the properties of HDF130 with the new and important constraint of the upper limit of the radio flux density at 240 MHz to an analytic model. We learn what values of physical parameters in the model for the dynamics and evolution of the radio luminosity and X-ray luminosity [due to IC scattering of the cosmic microwave background (CMB)] of a Fanaroff-Riley type II (FR II) source are able to describe a source with features (lobe length, axial ratio, X-ray luminosity, photon index and upper limit of radio luminosity) similar to those of the observations. HDF130 is found to agree with the interpretation that it is an IC ghost of a powerful double-lobed radio source, and we are observing it at least a few Myr after jet activity (which lasted 5-100 Myr) has ceased. The minimum Lorentz factor of injected particles into the lobes from the hotspot is preferred to be γ~ 10 3 for the model to describe the observed quantities well, assuming that the magnetic energy density, electron energy density and lobe pressure at time of injection into the lobe are linked by constant factors according to a minimum energy argument, so that the minimum Lorentz factor is constrained by the lobe pressure. We also apply the model to match the features of 6C0905+3955, a classical double FR II galaxy thought to have a low-energy cut-off of γ~ 10 4 in the hotspot due to a lack of hotspot IC X-ray emission. The models suggest that the low-energy cut-off in the hotspots of 6C0905+3955 is γ≳ 10 3 , just slightly above the particles required for X-ray emission. © 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS.


The inverse-Compton ghost HDF130 and the giant radio galaxy 6C0905+3955: Matching an analytic model for double-lobed radio source evolution

Monthly Notices of the Royal Astronomical Society (2011)

P Mocz, AC Fabian, KM Blundell, PT Goodall, SC Chapman, DJ Saikia


SS433's accretion disc, wind and jets: before, during and after a major flare

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 417 (2011) 2401-2410

KM Blundell, L Schmidtobreick, S Trushkin


The dynamics and stability of circumbinary orbits

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 418 (2011) 2656-2668

S Doolin, KM Blundell


When microquasar jets and supernova collide: Hydrodynamically simulating the SS433-W50 interaction

Monthly Notices of the Royal Astronomical Society (2011)

PT Goodall, F Alouani-Bibi, KM Blundell

We present investigations of the interaction between the relativistic, precessing jets of the microquasar SS433 and the surrounding, expanding supernova remnant (SNR) shell, W50, and the consequent evolution in the inhomogeneous interstellar medium (ISM). We model their evolution using the hydrodynamic flash code, which uses adaptive mesh refinement. We show that the peculiar morphology of the entire nebula can be reproduced to a good approximation, due to the combined effects of (i) the evolution of the SNR shell from the free-expansion phase through the Sedov blast wave in an exponential density profile from the Milky Way disc, and (ii) the subsequent interaction of the relativistic, precessing jets of SS433. Our simulations reveal: (1) Independent measurement of the Galaxy scaleheight and density local to SS433 (as n 0 = 0.2cm -3 ,Z d = 40pc), with this scaleheight being in excellent agreement with the work of Dehnen and Binney. (2) A new mechanism for hydrodynamic refocusing of conical jets. (3) The current jet precession characteristics do not simply extrapolate back to produce the lobes of W50, but a history of episodic jet activity having at least three different outbursts with different precession characteristics would be sufficient to produce the W50 nebula. A history of intermittent episodes of jet activity from SS433 is also suggested in a kinematic study of W50 detailed in a companion paper. (4) An estimate of the age of W50, and equivalently the age of SS433's black hole created during the supernova explosion, in the range of 17000-21000yr. © 2011 The Authors. Monthly Notices of the Royal Astronomical Society © 2011 RAS.


A New Way to Measure How Much Light Has Been Produced Since the Universe was Born

ACCRETION AND EJECTION IN AGN : A GLOBAL VIEW 427 (2010) 177-+

M Georganopoulos, RM Sambruna, D Kazanas, DS Davis, AN Cillis, CC Cheung, ES Perlman, KM Blundell

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