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BEGIN:VEVENT
DTSTAMP:20260428T052904Z
DTSTART;VALUE=DATE-TIME:20221128T130000
DTEND;VALUE=DATE-TIME:20221128T140000
SUMMARY:Vladislavs Bezrukovs (Ventspils International Radio Astronomy Cen
 tre): Ventspils International Radio Astronomy Centre (VIRAC): overview o
 f facilities and recent results
TZID:Europe/London
UID:20221128-8a1785d8847a84e2018480c5d5c82548@warwick.ac.uk
CREATED:20221121T104205Z
DESCRIPTION:Ventspils International Radio Astronomy Centre (VIRAC) of Ven
 tspils University of Applied Sciences (VUAS) was established in 1994 wit
 h the aim to develop the research activities in radio astronomy\, astrop
 hysics and space sciences. The most important instrumental base for the 
 centre comprised two fully steerable parabolic antennas\, RT-16 and RT-3
 2 (i.e. with the mirror diameter of 16 m and 32 m) and LOFAR-LATVIA stat
 ion. The intensive reconstruction and instrumental refurbishment carried
  out in 2014 – 2019 made it possible to use radio telescopes for the int
 ernational scale fundamental and applied research in the field of radio 
 astronomy. The most important aspect of this work is participation in th
 e VLBI (Very Long Baseline Interferometry) international experiments. Du
 ring the renovation\, radio telescopes were instrumented with two channe
 l right circular polarization (RCP) and left circular polarization (LCP)
  cryogenic broad band receivers with frequency coverage of 4.5 – 8.8 GHz
  and instantaneous bandwidth of approx. 1200 MHz. Receivers are cryogeni
 cally cooled to 14 Kelvin which nominally achieves system noise temperat
 ures of 30 to 50 Kelvin throughout the whole bandwidth. A secondary rece
 iver is available at RT-32 for observations at 1.40 to 1.72 GHz. It is a
 n uncooled receiver with dual (RCP and LCP) polarization channels and ac
 hieves system temperatures of 60 to 100 K. Each telescope has VLBI equip
 ment available\, which includes Active Hydrogen masers\, DBBC/Mark5c/Fle
 xBuff data registration back-ends and 10 Gbit optical fibre network. Max
 imum azimuth and elevation tracking velocities are up to 5 degrees/s wit
 h RMS tracking accuracies 4 arcsec allowing to track Near Earth satellit
 es. Additionally\, radio telescope RT-32 performs routine spectral polar
 imetric observations of the Sun by the multi-channel (16 frequency chann
 els) spectral polarimeter for the wavelength range 3.2 – 4.7 cm (6.3 - 9
 .3 GHz) and both circular polarizations. The new multi-channel spectral 
 polarimeter\, installed in 2022 is expected to observe right and left ci
 rcular polarization of the solar emission in the wavelength range 2.1 – 
 7.5 cm (4.1 – 14.3 GHz) divided into 12 frequency bands. The dynamic ran
 ge of the receiver is up to 36 db\; the signal/noise ratio (referred to 
 quiet Sun brightness temperatures) is 22-24 db. The LOFAR-Latvia is an i
 nternational LOFAR station (IS). It contains 96 low band (LBA) (10 - 90 
 MHz\, total area 3200 sq.m) and 96 high band (HBA) (110 - 240 MHz\, tota
 l area 2400 sq.m) antennas. One of the main scientific objectives for th
 e VIRAC centre is VLBI observations in centimetre and meter wavelengths 
 in collaboration with the global VLBI networks\, such as European VLBI n
 etwork (EVN)\, LOFAR\, IVS and others. The new receiving and recording s
 ystems provide a high stability of the time frame\, which is a prerequis
 ite for the VLBI observations. Since October 2015 VIRAC radio telescopes
  have regularly taken part in international VLBI sessions. VIRAC is a me
 mber of pan-European networks such as CERN (Member State since 2021)\, I
 nternational Low Frequency Array (LOFAR) Telescope (ILT) since 2019\, Eu
 ropean VLBI (EVN) and JIV-ERIC networks since 2016.
LOCATION:PLT
CATEGORIES:CFSA Seminar
LAST-MODIFIED:20221121T104205Z
ORGANIZER;CN=Anne-Marie Broomhall:
END:VEVENT
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