Alhambra sky survey maps galactic evolution

The picture shows a small fragment of the sky as seen in the most complete mapping of the sky available today. Sloan Digital Sky Survey (SDSS), right, and the same fragment observed by ALHAMBRA, left.

The ALHAMBRA project, led by researchers from the Instituto de Astrofísica de Andalucía and in which the University of Valencia has participated, has identified and classified more than half a million galaxies, after seven years of close observation of the universe from the Observatory of Calar Alto (CAHA, Almería) and thanks to a technique that breaks the stars energy in their colours through astronomical filters.

In addition, this research has also calculated the distances from these galaxies to us with unprecedented accuracy.

ALHAMBRA (Advanced Large, Homogeneous Area Medium Band Redshift Astronomical survey) has a system of twenty filters covering all wavelengths in the optical and three filters in the infrared, which accurately determines the energy emitted by galaxies and the distance of half a million galaxies with unprecedented depth for the sample size.

The ALHAMBRA mapping represents an ambitious scientific project that has mobilised scientists from sixteen research institutes.

Led by Mariano Moles (CEFCA) and developed in the Instituto de Astrofísica de Andalucía (IAA-CSIC), it was designed to trace the universe's evolution during the last ten million years.

"ALHAMBRA represents a decisive step to solve pressing issues in cosmology and astrophysics through photometric mapping, offering accuracy required to determine the distance of the detected objects," Moles says.

Thus, "the unbiased character of these mappings allows obtaining relevant data for all cosmic scales and, in this sense, the ALHAMBRA project is a precursor of the new long-range mapping that is being proposed."

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