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Kinematic properties of early-type galaxy haloes using planetary nebulae
L. Coccato, O. Gerhard, M. Arnaboldi +11
We present new planetary nebulae (PNe) positions, radial velocities, and magnitudes for 6 early-type galaxies obtained with the Planetary Nebulae Spectrograph, their two-dimensiona…
Probing the kinematics of early-type galaxy halos using planetary nebulae
L. Coccato, O. Gerhard, M. Arnaboldi +11
We present first results of a study of the halo kinematics for a sample of early type galaxies using planetary nebulae (PNe) as kinematical tracers. PNe allow to extend up to sever…
The PN.S Elliptical Galaxy Survey: the dark matter in NGC 4494
N. R. Napolitano, A. J. Romanowsky, L. Coccato +12
We present new Planetary Nebula Spectrograph observations of the ordinary elliptical galaxy NGC 4494, resulting in positions and velocities of 255 PNe out to 7 effective radii (25…
Modelling ultra-fine structure in dark matter halos
Daniele S. M. Fantin, Michael R. Merrifield, Anne M. Green
Various laboratory-based experiments are underway attempting to detect dark matter directly. The event rates and detailed signals expected in these experiments depend on the dark m…
Radial Dependence of the Pattern Speed of M51
Sharon E. Meidt, Richard J. Rand, Michael R. Merrifield +2
The grand-design spiral galaxy M51 has long been a crucial target for theories of spiral structure. Studies of this iconic spiral can address the question of whether strong spiral…
The link between the masses and central stellar populations of S0 galaxies
A. G. Bedregal, A. Aragón-Salamanca, M. R. Merrifield +1
Using high signal-to-noise ratio VLT/FORS2 long-slit spectroscopy, we have studied the properties of the central stellar populations and dynamics of a sample of S0 galaxies in the…
Tests of the Radial Tremaine-Weinberg Method
Sharon E. Meidt, Richard J. Rand, Michael R. Merrifield +2
At the intersection of galactic dynamics, evolution and global structure, issues such as the relation between bars and spirals and the persistence of spiral patterns can be address…
Dark-Matter Content of Early-Type Galaxies with Planetary Nebulae
N. R. Napolitano, A. J. Romanowsky, L. Coccato +10
We examine the dark matter properties of nearby early-type galaxies using planetary nebulae (PNe) as mass probes. We have designed a specialised instrument, the Planetary Nebula Sp…
Structure Through Colour: A Pixel Approach Towards Understanding Galaxies
M. M. Lanyon-Foster, C. J. Conselice, M. R. Merrifield
We present a study of pixel Colour Magnitude Diagrams (pCMDs) for a sample of 69 nearby galaxies chosen to span a wide range of Hubble types. Our goal is to determine how useful a…
The formation of S0 galaxies: evidence from globular clusters
J. M. Barr, A. G. Bedregal, A. Aragon-Salamanca +2
We test the theory that lenticular (S0) galaxies form from spirals whose star formation has been shut down. We use the globular cluster specific frequency S_N, defined as the numbe…
Central Stellar Populations of S0 Galaxies in The Fornax Cluster
A. G. Bedregal, A. Aragón-Salamanca, M. R. Merrifield +1
Based on FORS2-VLT long-slit spectroscopy, the analysis of the central absorption line indices of 9 S0 galaxies in the Fornax Cluster is presented. Central indices correlate with c…
S0 galaxies in Fornax: data and kinematics
A. G. Bedregal, A. Aragón-Salamanca, M. R. Merrifield +1
We have obtained long-slit spectroscopy for a sample of 9 S0 galaxies in the Fornax Cluster using the FORS2 spectrograph at the 8.2m ESO VLT. From these data, we have extracted the…
The Lifetime of Grand Design
M. R. Merrifield, R. J. Rand, S. E. Meidt
The lifetime of the structure in grand design spiral galaxies is observationally ill-determined, but is essentially set by how accurately the pattern's rotation can be characterize…
Integral Field Spectroscopy of 23 Spiral Bulges
D. Batcheldor, D. Axon, D. Merritt +7
We have obtained Integral Field Spectroscopy for 23 spiral bulges using INTEGRAL on the William Herschel Telescope and SPIRAL on the Anglo-Australian Telescope. This is the first 2…
The cool wake around 4C 34.16 as seen by XMM-Newton
I. Sakelliou, D. M. Acreman, M. J. Hardcastle +3
We present XMM-Newton observations of the wake-radiogalaxy system 4C34.16, which shows a cool and dense wake trailing behind 4C34.16's host galaxy. A comparison with numerical simu…
Mass-to-light ratio gradients in early-type galaxy haloes
N. R. Napolitano, M. Capaccioli, A. J. Romanowsky +6
Since the near future should see a rapidly expanding set of probes of the halo masses of individual early-type galaxies, we introduce a convenient parameter for characterising the…
Nuclear properties of a sample of nearby spirals from STIS imaging
C. Scarlata, M. Stiavelli, M. Hughes +17
We present surface photometry for the central regions of a sample of 48 spiral galaxies (mostly unbarred and barred of types Sbc or Sc) observed with the Space Telescope Imaging Sp…
Galaxy dynamics with the Planetary Nebula Spectrograph
N. R. Napolitano, A. J. Romanowsky, N. G. Douglas +6
The Planetary Nebula Spectrograph is a dedicated instrument for measuring radial velocity of individual Planetary Nebulae (PNe) in galaxies. This new instrument is providing crucia…
Early-type Galaxy Halo Dynamics inferred using the PN Spectrograph
N. G. Douglas, A. J. Romanowsky, K. Kuijken +6
A new instrument is providing crucial data with which to probe the structure of dark halos in elliptical galaxies.
Elliptical Galaxies: Darkly Cloaked or Scantily Clad?
A. J. Romanowsky, N. G. Douglas, K. Kuijken +7
Planetary nebulae (PNe) may be the most promising tracers in the halos of early-type galaxies. We have used multi-object spectrographs on the WHT and the VLT, and the new Planetary…
Is there a dichotomy in the Dark Matter as well as in the Baryonic Matter properties of ellipticals?
N. R. Napolitano, M. Capaccioli, M. Arnaboldi +5
We have found a correlation betwen the M/L global gradients and the structural parameters of the luminous components of a sample of 19 early-type galaxies. Such a correlation suppo…
A Dearth of Dark Matter in Ordinary Elliptical Galaxies
Aaron J. Romanowsky, Nigel D. Douglas, Magda Arnaboldi +5
The kinematics of the outer parts of three intermediate-luminosity elliptical galaxies have been studied using the Planetary Nebula Spectrograph. The galaxies' velocity dispersion…
Model-independent measurements of bar pattern speeds
Joris Gerssen, Konrad Kuijken, Michael R. Merrifield
The pattern speed in one of the fundamental parameters that determines the structure of barred galaxies. This quantity is usually derived from indirect methods or by employing mode…
The Galactic Bar
M. R. Merrifield
Like the majority of spiral galaxies, the Milky Way contains a central non-axisymmetric bar component. Our position in the Galactic plane renders it rather hard to see, but also al…