Astronomy and Coffee

News from the south

I´m at home!!!

Friday there was no science, since the trip is long. Couple of hours of train, long hours of plane and some hours waiting in between. Had to drink the terrible coffee from Lufthansa ... :-))

Weekend at home!

Today, no science, also, but I could write about the IAP conference, or aboutwhat the people said there!

After the Marseille and the IAP conference you can notice a selection effect on the talks, even though both conferences were about evolution of galaxies.

Marseille was more "high redshift" and deep surveys focused and IAP was more focused on simulations with some space to alternative theories.


First day was mainly simulations.

First Dekel opened with a talk where bimodality was the main topic, theyfind it at the luminosity function, age and surface brightness distributionsand it is attributed to the fact that below a critical mass there's no shockand you have a cold infall on the disk and above this mass you have shock. This would be the origin of the red and blue sequences ("dead and red" galaxies and star forming disks, respectively).

Julio Navarro showed some new simulations on galaxy formation, the part that called my attention was about the question that the central stars at created "in situ"and the stars accreted from destructed satellites form the halo. On this simulationmost of the satellites are destructed. He mentioned that there's an excess of starson the MW minor axis in the SDSS images and this also happens on M31.

Ben Moore commented that the "over merger" problem is almost solved on simulations.

Gottloeber mentioned environmental effects where triaxial haloes are determinedby the last merger and the most massive halos are aligned with the parents. Andthat stars are aligned with the Dark Matter and the gas.

Zentner showed that the alignment of the MW satellites in a polar distributionis not inconsistent with the simulations and with the "excess of small haloes".


On the second day more simulations.

Simon White told us that the central particles on z=0 haloes are spread around the haloesin z=1.

Salvador-Sole presented the results discussed some days ago, but with angular momentum.

Klypin showed cosmological simulations with gas that recover the rotation curves. Somerotating bar of DM following the stellar ones.

Gnedin presented the importance of adiabatic contraction on the simulations.

Now a little bit of observations.

McGaugh showed how MOND presents better results than other models to the rotation curves.

Ibata presented this very deep survey in M31 where lots of information about the galaxy halowere showed, a stream of 125 kpc was found and a new type of globular cluster was also identified.I still have to check if they are similar to the ones identified by Jean Brodie and Soren Larsenin S0 galaxies (the faint fuzzies).

To end the day models of polar rings by Combes, where accretion models show more similaritiesthan collision models, to form this kind of structure.


Third day models and observations.

Wilkinson reviewed the kinematics of the dSph of the local group. Velocities dispersionsof 7-10 km/s, core radii of 130 to 500 pc and M/L from 3 to 300. The results are consistentwith high M/L, cored DM distributions and M ~ 6 10^7 M_sol.

Romanowsky reviewed the masses of elliptical galaxies from internal kinematics using probessuch as PNe, GCs and X-ray. DM content of the faint elliptical may be a problem for LCDM andthe bright ones are a problem to MOND.

Mamon presented simulations showing the kinematical and dynamical modeling of mass profiles of elliptical galaxies using different profiles.


Forth day, the observational day!

Kochanek showed that lensing is the good probe for intermediate scales constraining total mass(light and DM) and not the mass distribution.

Brainerd showed that in SDSS the satellites are close to the major axis of the hosts, oppositeto the Holmberg effect.

Koopmans presented nice results using galaxy-galaxy lensing and spectroscopy to mass studies.

Arnaboldi presented the use of PNe to study the Intracluster component in Virgo and Coma. Virgo has 10% of its light in this component and it is very inhomogeneous showing large field to fieldvariations in the PNes counts. Coma also do not have a relaxed intracluster component. A veryinteresting technique to detect PNes in clusters using multislit spectroscopy and narrow bandfilters. I have to admit that this was the talk more related to my work, so that I really liked hehehehe

Zabludoff presented intracluster studies (the ones from Gonzales) the metallicity studies of thoseintracluster haloes by X-ray and variations on the fundamental plane, when you include thewhole cluster as an "spheroid". Those variations can be fitted when you add a second orderterm on the relation.

Ponman talked about groups studied using X-rays and also of the "fossil groups".
Fifth day more observations!! And the alternative theories.

Mellier reviewed the weak lensing.

Tully talked about observations of infall and caustics.

Clowe showed the shock of clusters which can be modeled using X-ray and weak lensing, constrainingthe DM haloes.

In the afternoon I was feeling very bad because of a cold that "finally" knocked me down and Ilost most of the talks, including Milgrom´s and Carroll´s. I could show up for Sanders talkingfor Bekenstein about the relativistic MOND and Woodard talking about a covariant formulationfor MOND.


Sixth and last day, I was like "half dead" because of the cold and six days of conferenceare too heavy :-)

The main discussion was on "how to test and rule out theories (CDM, MOND, ...)" but no real conclusions were ... achieved.

Of course there was a lot of coffee in Paris, some in nice places of the town!

Here in Brazil I already had some coffee (the best one) and I´be taking some back to Germany!

posted by Cris Da Rocha @ 1:25 AM