826 citations · 5.1k across the 61 of their papers we have counts for
21 papers · 1 filter
Dearth of dark matter or massive dark halo? Mass-shape-anisotropy degeneracies revealed by NMAGIC dynamical models of the elliptical galaxy NGC 3379
F. De Lorenzi, O. Gerhard, L. Coccato +10
Recent results from the Planetary Nebula Spectrograph (PN.S) survey have revealed a rapidly falling velocity dispersion profile in the nearby elliptical galaxy NGC 3379, casting do…
Testing the nature of S0 galaxies using planetary nebula kinematics in NGC 1023
E. Noordermeer, M. R. Merrifield, L. Coccato +9
We investigate the manner in which lenticular galaxies are formed by studying their stellar kinematics: an S0 formed from a fading spiral galaxy should display similar cold outer d…
The Importance of Mergers for the Origin of Intracluster Stars in Cosmological Simulations of Galaxy Clusters
G. Murante, M. Giovalli, O. Gerhard +3
We study the origin of the diffuse stellar component (DSC) in 117 galaxy clusters extracted from a cosmological hydrodynamical simulation. We identify all galaxies present in the s…
Diffuse Light in Hickson Compact Groups: The Dynamically Young System HCG 44
J. A. L. Aguerri, N. Castro-Rodriguez, N. Napolitano +2
Compact groups are associations of a few galaxies in which the environment plays an important role in galaxy evolution. The low group velocity dispersion favors tidal interactions…
A deep kinematic survey of planetary nebulae in the Andromeda Galaxy using the Planetary Nebula Spectrograph
H. R. Merrett, M. R. Merrifield, N. G. Douglas +13
We present a catalogue of positions, magnitudes and velocities for 3300 emission-line objects found by the Planetary Nebula Spectrograph in a survey of the Andromeda Galaxy, M31. O…
Planetary nebulae and stellar kinematics in the flattened elliptical galaxy NGC 1344
A. M. Teodorescu, R. H. Mendez, R. P. Saglia +4
We present photometric and kinematic information obtained by measuring 197 planetary nebulae (PNs) discovered in the flattened Fornax elliptical galaxy NGC 1344 (also known as NGC…
A boxy bulge in the Milky Way. Inversion of the stellar statistics equation with 2MASS data
M. Lopez-Corredoira, A. Cabrera-Lavers, O. E. Gerhard
Inverting the stellar statistics equation from 2MASS star counts, we obtain the 3D density distribution of the Galactic bulge as well as its luminosity function in the K-band. This…
The Diffuse Light in Simulations of Galaxy Clusters
G. Murante, M. Arnaboldi, O. Gerhard +8
We study the properties of the diffuse light in galaxy clusters forming in a large hydrodynamical cosmological simulation of the Lambda-CDM cosmology. The simulation includes a mod…
Evidence for a deficit of young and old stars in the Milky Way inner in-plane disc
M. Lopez-Corredoira, A. Cabrera-Lavers, O. Gerhard +1
We give independent proof of the deficit of stars in the in-plane central disc with respect to the predictions of a pure exponential density distribution. We use three different me…
Tracing the Star Stream Through M31 Using Planetary Nebula Kinematics
H. R. Merrett, K. Kuijken, M. R. Merrifield +12
We present a possible orbit for the Southern Stream of stars in M31, which connects it to the Northern Spur. Support for this model comes from the dynamics of planetary nebulae (PN…
Candidates for Intracluster Planetary Nebulae in the Virgo Cluster based on the Suprime-Cam Narrow-Band Imaging in O[III] and Halpha
S. Okamura, N. Yasuda, M. Arnaboldi +17
We have identified 38 candidates of intracluster planetary nebulae (ICPNe) in a field in the core of the Virgo cluster based on the Suprime-Cam imaging through two n…
Intracluster Planetary Nebulae in Virgo: Photometric selection, spectroscopic validation and cluster depth
M. Arnaboldi, J. A. L. Aguerri, N. R. Napolitano +6
We have imaged an empty area of 34'x34' one and a half degree north of the Virgo cluster core to survey for intracluster planetary nebula candidates. We have implemented and tested…
Detection, photometry and slitless radial velocities of 535 planetary nebulae in the flattened elliptical galaxy NGC 4697
R. H. Mendez, A. Riffeser, R. P. Kudritzki +5
We have detected 535 planetary nebulae (PNs) in NGC 4697, using the classic on-band, off-band filter technique with the Focal Reducer and Spectrograph (FORS) at the Cassegrain focu…
Implications of O and Mg abundances in metal-poor halo stars for stellar iron yields
D. Argast, M. Samland, F. -K. Thielemann +1
Inhomogeneous chemical evolution models of galaxies which try to reproduce the scatter seen in element-to-iron ratios of metal-poor halo stars are heavily dependent on theoretical…
The Galactic Center He I Stars: Remains of a Dissolved Young Cluster?
Ortwin Gerhard
A massive young star cluster, initially embedded in its parent molecular cloud, will spiral into the Galactic Center from $\lta 30m_6^{1/2}\pc$ during the life-time of its most mas…
Dark Matter Problem in Disk Galaxies
J. Binney, O. Gerhard, J. Silk
In the generic CDM cosmogony, dark-matter halos emerge too lumpy and centrally concentrated to host observed galactic disks. Moreover, disks are predicted to be smaller than those…
Stellar Dynamics in the Galactic centre: Proper Motions and Anisotropy
R. Genzel, C. Pichon, A. Eckart +2
We report a new analysis of stellar dynamics in the Galactic centre, based on improved sky and LOS velocities for >100 stars within a few arcsec of SgrA*. Overall the motions do no…
Discovery of 9 Ly alpha emitters at redshift z~3.1 using narrow-band imaging and VLT spectroscopy
R. P. Kudritzki, R. H. Mendez, J. J. Feldmeier +7
Narrow-band imaging surveys aimed at detecting the faint emission from the 5007 [O III] line of intracluster planetary nebulae in Virgo also probe high redshift z=3.1 Ly alpha emit…
Gas Dynamics and Large-Scale Morphology of the Milky Way Galaxy
Peter Englmaier, Ortwin Gerhard
We present a new model for the gas dynamics in the galactic disk inside the Sun's orbit. Quasi-equilibrium flow solutions are determined in the gravitational potential of the depro…
The stellar dynamics and mass of NGC 1316 using the radial velocities of planetary nebulae
M. Arnaboldi, K. C. Freeman, O. Gerhard +5
We present a study of the kinematics of the outer regions of the early-type galaxy NGC 1316, based on radial velocity measurements of 43 planetary nebulae as well as deep integrate…
Microlensing Optical Depth of the COBE Bulge
N. Bissantz, P. Englmaier, J. Binney +1
We examine the left-right asymmetry in the cleaned COBE/DIRBE near-infrared data of the inner Galaxy and show (i) that the Galactic bar is probably not seen very nearly end-on, and…