Archive for February 13, 2017

Signs of the Data Innovation Institute

Posted in Biographical with tags on February 13, 2017 by telescoper

I’ve only been in my new office in the Data Innovation Research Institute for 5 months so it came as a big surprise to see that they’ve already started putting up the signs telling people where we are. In fact a couple of chaps came this  morning to do the necessary, and now we look very professional. It’s hard to tell that this used to be a chip shop.


Please don’t tell the Health & Safety people about the power cable trailing through the window!

And here’s me answering the door to strangers…


Thanks to Dan Read for taking that second one.

R.I.P. Nicolai Gedda (1925-2017)

Posted in Opera with tags , , , on February 13, 2017 by telescoper

I only heard yesterday the very sad news that the fine Swedish operatic tenor Nicolai Gedda passed away on 8th January 2017 at the age of 91.  The news wasn’t announced by his family until February 9th, which explains part of the reason I am so late to post a little tribute. This is from the first recording I ever heard of die Zauberflöte by Wolfgang Amadeus Mozart (made in 1964, conducted by Otto Klemperer) in which Gedda sings Tamino alongside the equally wonderful Gundula Janowitz as Pamina.  This CD played a huge role in getting me interested in Opera, so it is with special sadness but also special admiration that I say farewell to Nicolai Gedda.

R.I.P. Nicolai Gedda (1925-2017)


Cosmological perturbation effects on gravitational-wave luminosity distance estimates [CL]

Posted in The Universe and Stuff on February 13, 2017 by telescoper

Interesting paper about the effect of cosmological inhomogeneity on gravitational wave propagation. The effect could be import for the more distant sources likely to be detected with future experiments.


Waveforms of gravitational waves provide information about a variety of parameters for the binary system merging. However, standard calculations have been performed assuming a FLRW universe with no perturbations. In reality this assumption should be dropped: we show that the inclusion of cosmological perturbations translates into corrections to the estimate of astrophysical parameters derived for the merging binary systems. We compute corrections to the estimate of the luminosity distance due to velocity, volume, lensing and gravitational potential effects. Our results show that the amplitude of the corrections will be negligible for current instruments, mildly important for experiments like the planned DECIGO, and very important for future ones such as the Big Bang Observer.

Read this paper on arXiv…

D. Bertacca, A. Raccanelli, N. Bartolo, et. al.
Wed, 8 Feb 17

Comments: 16 pages, 3 figures

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