Thursday, February 17, 2005

Mark Jackson & cosmic strings

Mark Jackson just gave us a very nice talk about cosmic strings. He used his Apple laptop with a PowerPoint presentation. The talk explained most of the issues about the types of cosmic strings and cosmic superstrings; their stability; the bounds for their density and tension; the probability of intercommuting pairs of F-strings, D-strings, (p,q)-strings, and all combinations of these objects; the gravitational waves emitted from the cusps and their detection by LIGO and LISA; and finally the candidates for cosmic strings, namely CSL-1A/CSL-1B and the 417-days-delayed double image.

The previous blog text about the cosmic strings was here.

The talk was not only a very nice review of all the stuff that we've discussed previously, but it also presented a shocking surprise: Mark has identified the coordinates of CSL-1 - the Cosmic String Lensing candidate. So far the coordinates have been largely secret.

Imagine that you're in charge of a telescope that is comparable to the Hubble telescope, or you have just launched your personal space shuttle which carries a probe, telescope, or something like that - and you want to see whether there is a discontinuity near the object CSL-1.

How do you find the coordinates?

You open the PDF version of the paper by Alcala et al.
and you search for "double early type". As a consistency check, the redshift should be z=0.463. Try to contact all your astro-friends and give them these coordinates of CSL-1. Well, to simplify your work, the coordinates are:
  • OACDF
    • right ascension: 12 hours, 23 minutes 30.6 seconds (note that this angle is measured in hours, 1 hour = 15 degrees)
    • declination: -12 degrees 38 minutes 57 seconds (southern celestial hemisphere, close to the equator)
    • double early type, z=0.463, S/N 12
Moreover, I've made another fun observation. The object listed just above this CSL-1 candidate is described as an "edge on disk" - well, this could be exactly the discontinuity by which the cosmic string cuts a disk in halves. Its coordinates are
    • 12h 23min 29.7sec, -12 deg 38' 27'', z=0.223 (?)