Astrophysics
LISA technology and instrumentation
Oliver Jennrich (European Space Agency) has prepared a large review on technical aspects of LISA (space laser interferometer) mission – the project is extremely complicated for realization, many technologies are not even yet fully developed, and various prototypes will have to be launched. Yet, possible payout is so huge – even including possible detection of gravitational waves from the very early Universe – from inflationary and reheating stages (just think about it – detecting EM radiation did not really allow us to go beyond redshift 
so far, not including here CMB of course). Who is a sucker for space research as I am – please check out the paper. It does not discuss science related to the mission but contains tons of technical information about LISA you won’t find anywhere else.
Read more on LISA technology and instrumentation…
A bit about climate change
Recently, an idea that sharp terrestrial climate change might be directly correlated to spiral arm passages of the Solar system became very popular. Namely, certain correlations of times of spiral arm passage with timing of ice ages and abundance of 
in fossils were claimed to be found (in the latter case, effective abundance of grows if gets locked up in ice). The basic idea is that if Solar system goes through spiral arms of the Milky Way, the event rate of cosmic rays in the Earth’s atmosphere greatly increases (since the number of supernovae in spiral arms is clearly much larger than in between the arms) and this presumably affects formation of clouds and therefore strength of greenhouse effect. However, in reality we don’t know very well when Solar system passed between the Galactic arms to make sufficiently strong statements about presence of such correlation.
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Other interesting things in ArXiv (12 Jun 2009)
Wayne Hu. Acceleration from modified gravity: lessons from worked examples. The main question Wayne Hu discusses in this minireview is “How can we distinguish dark energy from modified gravity theories if the former and the latter provide the same predictions for cosmological dynamics?” He is particularly focused on DGP and 
models. His answer is the presence of anisotropic stress for modified gravity models which is coupled directly to lensing potential – if we are able to measure this effect, we will be able to discriminate between IR modified gravity and dark energy. Another idea is to study behavior of theories in non-linear regimes, for example, by means of N-body simulation, and compare it to LSS.
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Lithium problem
Apart from being a very nice review of Big Bang Nucleosynthesis (BBN), recent paper by Karsten Jedamzik and Maxim Pospelov discusses an important open problem in the physics of BBN.
In short, the lithium problem in physics of Big Bang Nucleosynthesis is seeming underproduction of 
. What do we mean by that?
Other interesting things in ArXiv (11 Jun 2009)
Basically, there were so many interesting and useful papers (or at least they were useful for me) – lecture notes, reviews – that it will give me hard time posting reviews of all of them here – since I am lazy, I’ll just try to list some of them.
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Into dark ages or again about GRB090423
Back in April, I already wrote about GRB090423 – currently the most distant detected object in the Universe. Yesterday, two papers with details of mesurement have appeared in astro-ph (unfortunately, Icannot give you the links – see my comment below).
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How to spot a black hole on the Sky
Here is a video from NewScientist featuring simulations by Loeb and his collaborators (we have discussed Loeb’s results several times on NEQNET). The idea is that BH acts as a strong gravitational lense, so if we have a close system “star-BH”, we will see a very specific pattern of light when the companion star crosses the “disk” of BH. Of course, in order for us to spot this pattern, it is better if the line of our sight lights in the orbit plane of the star.
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This and that in ArXiv on Monday
Due to unbelievable overload of the last days let me simply list the recent papers in ArXiv that I found the most interesting:
1. Quantum information
T. Tilma el al., “Is entanglement a critical resource for quantum metrology?”
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An exoplanet near ultracool star
New record in astrometry and exoplanetology – the authors of 0906.0544 are talking about discovery of the planet in the vicinity of a very light star. The mass of the star is about 0.07 Solar masses, i.e., equivalent to 3-9 Jupiter masses – it is actually near the lower mass limit for an object to be called a star 
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Workshop on tests of gravity at Case Western – day 1
Dear friends,
I am sorry for being rather quiet for a while. As many of you may already know, my laptop has decided to enter coma during the trip, as a result, I was left without appropriate internet access (sporadic use of Pascal Vaudrevange’s computer is not counted, thanks, Pascal!). Although the laptop tried to revive after we came back home, demonstrating some kind of “brain” activity, in a couple of days I understood that the growth of entropy is as inevitable as a finally victory of string theory over loop quantum gravity.
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(In)visible Z’ and dark matter
Alberto Romagnoni is a postdoc at LPT, Orsay. Dmitry.
In this post I discuss my recent work “(In)visible Z’ and dark matter”, done in collaboration with E. Dudas, Y. Mambrini and S. Pokorski. I think there are two main messages I should stress to summarize our paper. The first one is more interesting for its phenomenological consequences and a possible striking signature for dark matter. The second one is more important from a theoretical point of view, and concerns the so-called “decoupling” theorem.
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Fermi telescope does not confirm DM claims
Fermi Space Telescope (image by NASA)
Fermi gamma-ray space telescope was unable to predict the presence of the 300-800 GeV peak in the distribution function of high energy electrons in cosmic rays. Let me remind you that the anomaly we are talking about was claimed to be found by the ATIC team and generated recently a lot of buzz in high energy physics community (one source of those high energy electrons may be decay of dark matter particles).
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382. Lester Lyles is not to be the next NASA administrator
Lester Lyles, retired air force general, has confirmed yesterday that he has taken his name out of consideration for the NASA administrator post. He was clearly a favorite in the run started on Jan 20, to the point that Obama administration pushed him to take the post. I think it would be fair to say – thank you, Mr. Lyles.
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380. Lightest exoplanet found: video of the day
… as announced on Apr 21. Discovered planet is only about twice as massive the Earth.
378. Sounds of Jupiter: video (or better say – audio?) of the day
Damn if it does not sound like Stanley Kubrick’s “2001: Space odyssey” Did he actually know? Although these particular sounds were recorded in 1988, I bet people have heard them back in 1950s-60s, and Clarke should have told Kubrick about them.
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