Non-thermal X-rays, a high abundance ridge and fossil bubbles in the core of the Perseus cluster of galaxies

Using a deep Chandra observation of the Perseus cluster of galaxies, we find a high-abundance shell 250 arcsec (93 kpc) from the central nucleus. This ridge lies at the edge of the Perseus radio mini-halo. In addition we identify two Halpha filaments pointing towards this shell. We hypothesise that this ridge is the edge of a fossil radio bubble, formed by entrained enriched material lifted from the core of the cluster. There is a temperature jump outside the shell, but the pressure is continuous indicating a cold front. A non-thermal component is mapped over the core of the cluster with a morphology similar to the mini-halo. Its total luminosity is 4.8x10^43 erg/s, extending in radius to ~75 kpc. Assuming the non-thermal emission is the result of inverse Compton scattering of the CMB and infrared emission from NGC 1275, we map the magnetic field over the core of the cluster.Comment: 8 pages, colour, accepted by MNRA

A prominent relativistic iron line in the Seyfert 1 MCG-02-14-009

I report the discovery of a prominent broad and asymmetrical feature near 6.4 keV in the Seyfert 1 MCG-02-14-009 (z=0.028) with XMM-Newton/EPIC. The present short X-ray observation (PN net exposure time ~5 ks) is the first one above 2 keV for MCG-02-14-009. The feature can be explained by either a relativistic iron line around either a Schwarzschild (non-rotating) or a Kerr (rotating) black hole. If the feature is a relativistic iron line around a Schwarzschild black hole, the line energy is 6.51 (+0.21,-0.12) keV with an equivalent width of 631 (+259,-243) eV and that the inclination angle of the accretion disc should be less than 43 degrees. A relativistically blurred photoionized disc model gives a very good spectral fit over the broad band 0.2-12keV energy range. The spectrum is reflection dominated and this would indicate that the primary source in MCG-02-14-009 is located very close to the black hole, where gravitational light bending effect is important (about 3-4 Rg), and that the black hole may rapidly rotate.Comment: Accepted for publication, A&A Letters, 5 pages, 3 figures, and 1 tabl

Chandra observations of Abell 2199

We present results from an analysis of two Chandra observations of the rich, nearby galaxy cluster Abell 2199. We find evidence (having corrected for projection effects) for radial gradients in temperature and metallicity in the X-ray emitting gas: the temperature drops from kT~4.2 keV at R=200 kpc to 1.6 keV within R=5 kpc of the centre. The metallicity rises from ~0.3 solar at R=200 kpc to ~0.7 solar at R=30 kpc before dropping to 0.3 solar within the central 5 kpc. We find evidence for structure in the surface brightness distribution associated with the central radio source 3C338. No evidence is found for the gas having a large spread in temperature at any particular location despite the cooling time being short (<10**9yr) within the central ~15 kpc. Heating and mass cooling rates are calculated for various assumptions about the state of the gas.Comment: 10 pages, 12 figures. Accepted by MNRAS. Minor changes following referee's comment

Spatially-resolved X-ray spectroscopy of the core of the Centaurus cluster

We present Chandra data from a 31.7 ks observation of the Centaurus cluster, using the ACIS-S detector. Images of the X-ray emission show a plume-like feature at the centre of the cluster, of extent 60 arcsec (20 kpc in projection). The feature has the same metallicity as gas at a similar radius, but is cooler. Using adaptive binning, we generate temperature, abundance and absorption maps of the cluster core. The radial abundance profile shows that the previously known, steep abundance gradient peaks with a metallicity of 1.3-1.8 Zsolar at a radius of about 45 arcsec (15 kpc), before falling back to 0.4 Zsolar at the centre of the cluster. A radial temperature profile shows that the temperature decreases inwards. We determine the spatial distributions of each of two temperature components, where applicable. The radiative cooling time of the cooler component within the inner 10 arcsec (3 kpc) is less than 2x10^7 yr. X-ray holes in the image coincident with the radio lobes are seen, as well as two outer sharp temperature drops, or cold fronts. The origin of the plume is unclear. The existence of the strong abundance gradient is a strong constraint on extensive convection or gas motion driven by a central radio source.Comment: 11 pages, 14 figures (3 colour), accepted by MNRAS, high res. version at http://www-xray.ast.cam.ac.uk/papers/cen1_accptd.pdf . Updated version includes a section considering a non-thermal componen

An X-ray absorption analysis of the high-velocity system in NGC 1275

We present an X-ray absorption analysis of the high-velocity system (HVS) in NGC 1275 using results from a deep 200 ks Chandra observation. We are able to describe the morphology of the HVS in more detail than ever before. We present an HST image for comparison, and note close correspondence between the deepest X-ray absorption and the optical absorption. A column density map of the HVS shows an average column density NH of 1x10^21 cm^-2 with a range from ~5x10^20 to 5x10^21 cm^-2. From the NH map we calculate a total mass for the absorbing gas in the HVS of (1.32+-0.05)x10^9 solar masses at solar abundance. 75 per cent of the absorbing mass is contained in the four regions of deepest absorption. We examine temperature maps produced by spectral fitting and find no direct evidence for shocked gas in the HVS. Using deprojection methods and the depth of the observed absorption, we are able to put a lower limit on the distance of the HVS from the nucleus of 57 kpc, showing that the HVS is quite separate from the body of NGC 1275.Comment: 6 pages, 5 colour figures, accepted by MNRA

Your supervisor’s personality impacts you forever

Supervisors are different in their managerial abilities and in how they perceive your work, yet their decisions determine you career outcomes, write Anders Frederiksen, Lisa Kahn, and Fabian Lang

Entangled momentum modes for atom interferometry

Entangled ensembles have been created in versatile atomic systems and find a promising application in entanglement-enhanced metrology. Here, entangled spin-states have been successfully applied within interferometers that allow to measure magnetic fields and frequencies with enhanced sensitivities. In contrast, atom interferometers for the measurement of inertial forces and gravitational fields are operated in external degrees of freedom and span an area in space-time. To make use of entangled states here, the entanglement has to be generated among momentum modes with suitable spatial extent and velocity width. In this thesis, a source of momentum-entangled atoms that is compatible with present-day light-pulse atom interferometers is presented. Utilising a quasi-adiabatic ramp through a quantum phase transition, highly-entangled twin-Fock states are created in the internal spindegree of freedom of a 87Rb Bose-Einstein condensate. Hereon, the entanglement is successfully transferred to distinct momentum-modes by a stimulated Raman coupling and verified by the direct measurement of an entanglement criterion. The observed mode quality and the residual expansion demonstrate that this entangled source is wellsuited to the successive application in light-pulse atom interferometers and opens up a path to gravimetry beyond the standard quantum limit. Furthermore could the demonstrated techniques be employed to realise a scalable atomic Bell test. In the long run, similar entangled sources could specifically enhance the performance of gravity gradiometers, tests of the Einstein Equivalence Principle and future atomic gravitational wave detectors.Verschränkte Zustände wurden in vielen atomaren Systemen erzeugt und finden ein aussichtsreiche Anwendung in der verschränkungsgestützten Metrologie. Hier wurden verschränkte Spinzustände erfolgreich in Interferometern eingesetzt, mit denen Magnetfelder und Frequenzen mit erhöhter Empfindlichkeit gemessen werden können. Im Gegensatz dazu werden Atominterferometer zur Messung von Beschleunigungen und Gravitationsfeldern in externen Freiheitsgraden betrieben und spannen eine Fläche in der Raumzeit auf. Um hier verschränkte Zustände nutzen zu können, muss die Verschränkung zwischen Impulszuständen mit geeigneter räumlicher Ausdehnung und Geschwindigkeitsbreite erzeugt werden. In dieser Arbeit wird eine Quelle für impulsverschränkte Atome vorgestellt, die mit heutigen Atominterferometern kompatibel ist. Unter Verwendung einer quasi-adiabatischen Rampe durch einen Quantenphasenübergang werden hochverschränkte Zwillings-Fock- Zustände im inneren Spin-Freiheitsgrad eines 87Rb Bose-Einstein- Kondensats erzeugt. Die Verschränkung wird durch eine stimulierte Raman-Kopplung erfolgreich in den Impulsraum übertragen und durch die direkte Messung eines Verschränkungskriteriums verifiziert. Die beobachtete Modenqualität und die Restexpansion zeigen, dass sich diese verschränkte Quelle gut für die sukzessive Anwendung in Atominterferometern eignet und einen Weg zur Gravimetrie jenseits des Standard-Quantenlimits eröffnet. Darüber hinaus könnten die aufgezeigten Techniken zur Durchführung eines skalierbaren atomaren Bell Tests eingesetzt werden. Langfristig könnten ähnliche verschränkte Quellen insbesondere die Leistung von Gravitationsgradiometern, Tests des Einsteinschen Äquivalenzprinzips und zukünftigen atomaren Gravitationswellendetektoren verbessern