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Summary:
This is the homepage of the of the weekly Astrophysics journal club at the Division of Particle physics and astrophysics at the University of Helsinki.
The meetings are of an unofficial nature and the main driver is to get together and discuss recent interesting papers. This meeting differs from the
Seminar series in that people are not expected to talk about their own research and in that no credits will be awarded to students. The meetings are
open to everyone and the aim is to stimulate discussion about recent results and provide the possibility to
 learn about research that is not necessarily
connected to one's own field of expertise.

All topics are welcome ranging from planetary science to larger scales involving stellar
 astrophysics, Milky Way studies, galaxies and cosmology.
The only requirement is that the
 presented papers should be interesting to a wider audience and that they should be presented 
in such a way that also
a non-expert can follow the presentation. In the meetings we discuss one paper each week for about 45 minutes.
 All meetings are in English.

Location: Conference room C310 on the third floor.

Time: Thursdays at 10.15-11.00am during term time.

Speakers: Please contact Peter Johansson, Mikael Granvik or Clif Kirkpatrick if you want to present a paper.

Present Program: The next talk will be on the 2nd of May

Presenter: Ghassem Gozaliasl:
Paper title: Phase-space Analysis in the Group and Cluster Environment: Time Since Infall and Tidal Mass Loss
Authors: Rhee, J., Smith, R., Choi, H. et al.
Reference: 2017, ApJ, 843, 128

Abstract: Using the latest cosmological hydrodynamic N-body simulations of groups and clusters, we study how location in phase-space coordinates at z = 0 can provide information on environmental effects acting in clusters. We confirm the results of previous authors showing that galaxies tend to follow a typical path in phase-space as they settle into the cluster potential. As such, different regions of phase-space can be associated with different times since first infalling into the cluster. However, in addition, we see a clear trend between total mass loss due to cluster tides and time since infall. Thus, we find location in phase-space provides information on both infall time and tidal mass loss. We find the predictive power of phase-space diagrams remains even when projected quantities are used (I.e., line of sight velocities, and projected distances from the cluster). We provide figures that can be directly compared with observed samples of cluster galaxies and we also provide the data used to make them as supplementary data to encourage the use of phase-space diagrams as a tool to understand cluster environmental effects. We find that our results depend very weakly on galaxy mass or host mass, so the predictions in our phase-space diagrams can be applied to groups or clusters alike, or to galaxy populations from dwarfs up to giants.

Present program:

 

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Spring 2019:


Autumn 2018:


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