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TIDK #2 – My gravitational radius
One thing I learned pretty quickly was that astronomers don’t only use a lot of weird units (like milliCrabs for example – more on this in another post) but they also use a lot of terms that don’t mean much at first hearing by the unenlightened. One such is ‘gravitational radius’… someone may say that something is ‘three gravitational radii from” an object. Continue reading “TIDK #2 – My gravitational radius”
eROSITA’s new X-ray map of the Universe
This really is a brilliant time to be an X-ray astronomer. Launched on 13th July 2019 on board the SRG spacecraft, the eROSITA X-ray telescope has completed its first full sweep of the sky, mapping more than a million energetic objects and so roughly doubling the number of known X-ray sources discovered since the dawn of X-ray astronomy some 60 years ago. Continue reading “eROSITA’s new X-ray map of the Universe”
TIDK #1 – Neutron star interiors
TIDK = Things I Didn’t Know… until I started gathering the knowledge that in another lifetime may have made me a professional astronomer. This may become a long list…
I knew that neutron stars were stellar remnants, leftovers of stars that had finished with nuclear fusion and collapsed under their own gravity to the point where protons and electrons were crushed together to create more neutrons to join those that were there already. So my answer would have been “neutrons” whether you had asked me “what’s the surface made of?” or “what’s the centre made of?”. Neutrons all the way down and through. Continue reading “TIDK #1 – Neutron star interiors”
Prospective method of measuring neutron star radius/mass ratios
For the detail behind the content of this post see “Neutron Star Radius-to-Mass Ratio from Partial Accretion Disc Occultation as Measured through Fe Kα Line Profiles” as submitted to ApJ by Riccardo La Placa et al, March 2020. Continue reading “Prospective method of measuring neutron star radius/mass ratios”
Free text books
If you have an institutional sign-in to Springer Nature then you have the opportunity to download free soft copies of hundreds of text books. Springer Nature has taken this admirable initiative in support of worldwide learning and teaching institutions which are currently closed because of the Corona virus pandemic.
Simply click on this link and then download an Excel spreadsheet giving details of all the books on offer, including a download URL for each one. Continue reading “Free text books”