Name: Ivan Valtchanov (Ph.D.)

ESA Herschel

Nationality: Bulgarian.
Scientific interest keywords: large-scale structure of the
                              Universe;  clusters of galaxies;
                              groups of galaxies; observations:
                              optical, X-ray, infrared.

I moved to ESAC from Imperial College, London in September 2005.  
I am Instrument and Calibration Scientist for one of the Herschel
Space  Observatory instruments - the Spectral and Photometric
Imaging Receiver (SPIRE).

My scientific interests are in the field of the large-scale
structure of the Universe and mainly on the building bricks of the
cosmic web, the knots at the intersections of the filamentary
structure, also known as clusters of galaxies. These are the most
massive virialised objects in the Universe and as such provide
important constraints on cosmology, independent and complementary
to those from CMB and supernovae studies.

I am involved in one of the largest extragalactic observing
programs with XMM: the XMM Large-Scale Structure Survey (XMM-LSS)
with some 10 deg^2 contiguous area coverage to date. In fact, my
PhD, which I did in France some years ago, was based on the first
XMM observations in the XMM-LSS field. My involvement includes
multi-wavelength follow-up observations and data analysis:
photometry and spectroscopy in the optical/near-infrared bands and
wide-band observation in the infrared with Spitzer (Spitzer Wide
InfraRed Extragalactic survey - SWIRE).

I started my work on the galaxy clusters in Bulgaria, before my
PhD. At that thime I also did some work on the largest (the most
massive) known non-virialised structures in the Universe: the
superclusters of galaxies, which are clusters of clusters of
galaxies.