Another Word For It Patrick Durusau on Topic Maps and Semantic Diversity

November 2, 2012

CALIFA First Data Release

Filed under: Astroinformatics,BigData,Data — Patrick Durusau @ 6:35 am

CALIFA (Calar Alto Legacy Integral Field spectroscopy Area survey) First Data Release

From the webpage:

The Calar Alto Legacy Integral Field Area survey is one of the largest IFS surveys performed to date. At its completion it will comprise 600 galaxies, observed with the PMAS spectrograph in the PPAK mode, covering the full spatial extent of these galaxies up to two effective radii. The wavelength range between 3700 and 7500 Å is sampled with two spectroscopic configurations, a high resolution mode (V1200, R~1700, 3700-4200 Å), and a low resolution mode (V500, R~850, 3750-7500 Å). A detailed explanation of the survey is given in the CALIFA Presentation Article (Sánchez et al. 2012).

The first CALIFA Data Release (DR1) provides to the public the fully reduced and quality control tested datacubes of 100 objects in both setups (V500 and V1200). Each datacube contains ~2000 individual spectra, thus in total this DR comprises ~400,000 individual spectra. The details of the data included in this DR are described in the CALIFA DR1 Article (Husemann et al. 2012). The complete list of the DR1 objects for which we deliver data can be found in the following webpage.

The main characteristics of the galaxies included in the full CALIFA mother sample, a subset of which are delivered in this DR, will be given in the CALIFA sample characterization article (Walcher et al. in prep.). This article will provide detailed information of the photometric, morphological and environmental properties of the galaxies, and a description of the statistical properties of the full sample.

The non-technical explanation:

Galaxies are the large-scale building blocks of the cosmos. Their visible ingredients include between millions and hundreds of billions of stars as well as clouds of gas and dust. “Understanding the dynamical processes within and between galaxies that have shaped the way they are today is a key part of understanding our wider cosmic environment.”, explains Dr. Glenn van de Ven, a member of the managing board of the CALIFA survey and staff scientist at the Max Planck Institute for Astronomy (MPIA).

Traditionally, when it came to galaxies, astronomers had to choose between different observational techniques. They could, for instance, take detailed images with astronomical cameras showing the various features of a galaxy as well as their spatial relations, but they could not at the same time perform detailed analyses of the galaxy’s light, that is “obtain a galaxy spectrum”. Taking spectra required a different kind of instrument known as a spectrograph, which, as a downside, would only provide very limited information about the galaxy’s spatial structure.

An increasingly popular observational technique, integral field spectroscopy (IFS), combines the best of both worlds. The IFS instrument PMAS mounted at the Calar Alto Observatory’s 3.5 metre telescope uses 350 optical fibres to guide light from a corresponding number of different regions of a galaxy image into a spectrograph. In this way, astronomers are not restricted to analysing the galaxy as a whole – they can analyse the light coming from many different specific parts of a galaxy. The result are detailed maps of galaxy properties such as their chemical composition, and of the motions of their stars and their gas.

For the CALIFA survey, more than 900 galaxies in the local Universe, namely at distances between 70 and 400 million light years from the Milky Way, were selected from the northern sky to fully fit into the field-of-view of PMAS. They include all possible types, from roundish elliptical to majestic spiral galaxies, similar to our own Milky Way and the Andromeda galaxy. The allocated observation time will allow for around 600 of the pre-selected galaxies to be observed in depth.

From: CALIFA survey publishes intimate details of 100 galaxies

Either way, I thought you would find it an interesting “big data” set to consider over the weekend.

Or if you are an amateur astronomer with a cloudy weekend, something to expand your horizons.

No Comments

No comments yet.

RSS feed for comments on this post.

Sorry, the comment form is closed at this time.

Powered by WordPress