Studies of CSS/GPS sources with the Deep Space Network ...

Studies of CSS/GPS sources with the Deep Space Network ...

Studies of CSS/GPS sources with the

Deep Space Network antennas in


Abstract: This presentation summarizes the antennas and receivers

available at the Madrid Deep Space Communication Complex

(Spain), and outlines the type of observations that can be

performed to contribute to the study of CSS/GPS sources.

Cristina Garcia Miro

MDSCC Overview


receiving bands


single dish studies: radiometric

observations and spectroscopy

DSN advantages for surveys

MDSCC Overview: antennas

MDSCC Overview: observing bands

Telescope DSS-63 (70m) DSS-65 (34m) DSS-54/55 (34m)

Obs. band L S X K S X S X Ka Q

C. freq (Ghz) 1.6 2.2 8.4 18-26 2.2 8.4 2.2 8.4 32 40-50

BW (MHz) 90 140 400 70(400) 100 400 140 400 400 70

Polarization dual (LCP at L) dual dual

resol (arcmin) 10.8 6.5 1.8 0.75 16.2 4.2 16.2 4.2 1.0 0.7

A eff(%) 60 72 65 47 61 73 76 77 60 50

Tsys (K) 29 19.8 16.3 50 33 25 37 23 38 80

MDSCC Overview: receivers

MarkIV DAT with 2 Mark5A recorders for VLBI

ACME: Antenna Calibration and Measurement Equipment

SPB500 spectrometer

WVSR: Wide band VLBI science receivers

MDSCC Overview: ACME

ACME: Antenna Calibration and Measurement Equipment

standard DSN calibration tool developed at MDSCC

process 2 data channels simultaneously

performs cross-scans in EL and XEL

DCOS predicts for antenna movement

full control station calibration equipment

2D raster scans over extended sources

single dish flux monitoring, pointing, subreflector optimization, efficiency


Single dish studies: flux monitoring

example: MKN668 multi-frequency flux monitoring

Project to look for correlation between radio and X-rays for a

disk-jet coupling model

opacity corrected, source size correction, using 3C295 as

efficiency calibrator

MDSCC Overview: SPB500 spectrometer

digital autocorrelator spectrometer

for 1.3cm (70m) and 7mm (34m) spectroscopy

maximum velocity resolution of 0.07km/s and 1 sigma noise level of ~30mJy

after 30min integration

2 resolution configurations: 1024 or 384 channels

currently bandwidth limited to 70MHz, about 1000km/s with 1km/s resolution

future upgrade: tunable YIG filter up to 400MHz BW, with 1024 channels,

about 5400km/s with 5km/s resolution

Single dish studies: water megamasers search

water megamasers search in radio quiet

AGN (SY2 and LINERs)

SAO4K autocorrelator, similar to

SPB500, 400Mhz bandwidth

typical 1 sigma noise levels in 1h

position switching ~14mJy in 1.3 km/s


H2O maser emission traces dense (>10 7

cm -3 ) warm (T kin

≥ 400K) molecular gas

nuclear torus viewed edge-on (large line

of sight column densities)

traces accretion disks (0.1-3pc) rotation

Kondratko et al. 2006

MDSCC Overview: WVSR

Wide band VLBI Science Receiver

Open loop receiver to support spacecraft

navigation at the DSN (DDOR experiments)

WVSR processes 2 IF analog data channels

about 600MHz wide centered at 315MHz.

Filters and digitizes the signal at 1280 Msamp/s

with 8-bit resolution. Further down convert it to

baseband, and select several portions of it with

the use of narrow band and wide band digital

filters. The digital samples of these filters are

time tagged and recorded for later processing.

MDSCC Overview: WVSR

total available data rate is 84 Mbits/s: 2x16MHz filters at 1-bit

Doppler shifts corrected via frequency predicts while observing

flexible spectrometer, polarimetric spectroscopy

Process of the data using RAVI: number of channels and number of FFTs to

average together for every second, hanning filtered (compromise between

resolution and sensitivity)

Single dish studies: galactic spectroscopy

Palau et al, in preparation

Single dish studies: water megamasers search

in GPS/CSS sources

First megamaser in radio loud FRII 3C403 (Tarchi et al. 2003)

no detection on FRI: lack of optically thick molecular torus

preliminary results on MKN668 and 4C+12.50

resolution: 62MHz BW, 840Km/s, 1024 channels, resolution ~1km/s

sensitivity: in 1h integration ~30mJy


Do young sources have

developed a torus thick enough

for maser amplification?

search for candidates

ask for DSN guest observer time

improve bandwidth for larger

velocity ranges (phase2 WVSR)

K-band: z < 0.25

X-band: 1.55 < z < 1.7

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