Status attuale e prospettive future del Sardinia Radio ... · Status attuale e prospettive future...

Istituto Nazionale di Astrofisica Sardinia Radio Telescope

Super-risoluzione in Radioastronomia, 12 Ottobre 2017, Villa Galileo, Firenze

Status attuale e prospettive future del

Sardinia Radio Telescope (SRT)

A. Navarrini a nome del team SRT

INAF (Istituto Nazionale di Astrofisica)

Osservatorio Astronomico di Cagliari



SRT Project

Collaboration among three Research Structures of INAF:

• INAF Astronomical Observatory of Cagliari, Cagliari

• INAF Institute of Radio Astronomy, Bologna

• INAF Arcetri Astrophysical Observatory, Florence

Main Funding Institutions:

• MIUR (Italian Ministry of Education and Scientific Research)

• ASI (Italian Space Agency)

• RAS (Sardinia Regional Government)

Cost 60 MEuro

64 m diameter fully steerable radiotelescope to cover 0.3-116 GHz:- Single dish operation

- Part of VLBI network

- Radioastronomy, geodynamical studies, Deep Space Network



SRT site

Altitude a.s.l. ≈600 m

Latitude +390 29m 50s



SRT technical specificationsPrimary mirror D=64 m; Secondary mirror D=7.9 m

Gregorian configuration with shaped surfaces

Six focal positions: Primary,

Gregorian, & four Beam Wave Guide

Primary surf. accuracy:150 m RMS

Frequency agility

Pointing accuracy (RMS): 2 ÷ 5 arcsec

Can host up to 20 dual polarization

receivers: mono feed, dual frequency,

multibeam, phased array feeds

0.3-116 GHz frequency coverage

Active Surface: Primary mirror adjustable with 1116 actuators to compensate gravitational

deformation of the BKS; also used to convert shaped surface to parabolic for primary focus

operation

Optical Configuration and Ray Tracing of SRT

Primary Focus

F1/D =0.33

300MHz < f < 20GHz

Beam Wave Guide Foci

F3/D=1.37

F4/D = 2.81 (not shown)

1.4GHz < f < 35GHz

Gregorian Focus

F2/D =2.35

7.5GHz < f < 116GHz

Active surface: shape of primary mirror controlled with actuators

Compensate deformations of the primary mirror Convert shaped profile to a true-parabola (for primary focus) Compensate deformations of the secondary mirror

Active surface: the actuators

0.015mm/30mm

0.36mm/s

Weight: 12kg

-10° +60oC

Active surface: the actuators

actuators

1116 actuators



Six-month Early Science Program completed by Aug. 2016

12 large programs allocated for a total

of ≈2000 hours observing time

Front-EndFreq. range

[GHz]

Focal

position,

F/D

N. Pixels

× pols

Measured/

Expected*

receiv. noise

temp. [K]

Status

L- and P- band

coaxial feed

P: 0.305-0.410 Primary

0.33

1 × 2 17-22 Commissioned

L: 1.3-1.8 1 × 2 10-13 Commissioned

High C-band 5.7-7.7BWG I

1.371 × 2 6.5-9 Commissioned

K-band 18-26.5Gregorian

2.357 × 2 20-40 Commissioned

S-band 3.0-4.5Primary

0.337 × 2 15*

Under

construction

Low C-band 4.2-5.6BWG II

2.811 × 2 8*

Under

construction

Q-band 33-50Gregorian

2.3519 × 2 25*

Under

construction

W-band 84-116Gregorian

2.351 × 1 30-45

Under

construction

X-band (ASI) 8.2-8.6BWG II

2.811 × 2 15 Commissioned

SRT Front-Ends built and under construction at INAF

Commissioned SRT Front-Ends developed by INAFL-P band coaxial feed

P: 305-410 MHz

L: 1.3-1.8 GHz

K-band multibeam18-26.5 GHz

High-C-band monofeed5.7-7.7 GHz



Front-Ends installed at the SRT primary focus

L-P band

receiver

Holographic

receiver

(11 GHz)

X-Ka band

receiver

7.9 m diameter

secondary mirror

S band 7-beam receiver forthcoming



High-C band, installedLow-C-Band,

forthcoming

Movable

M3

K band multibeam,

installedSecondary focus

positioner

(rotating turrett)

Front-Ends at the Gregorian and BeamWaveGuide (BWG) foci

Q band & 3 mm band,

forthcoming

Secondary

focus



K-band multibeam receiver installed on SRT

July 2012



SRT backends

• DFB (Digital Filter Bank): 1 GHz BW full-Stokes; up to 2048 ch.,

folding and search mode (Pulsars);

• Roach1: 512 MHz BW, sw correlation - CPU cluster (Pulsars);

• XARCOS: 62.5 MHz, 7 beams dual pol., 2048 ch., freq. res. down

to 0.25 KHz (spectroscopy);

• Total Power: up to 7 beams dual pol., 2 GHz BW;

• Sardara, Roach2: 2.3 GHz BW, 7 beams full-Stokes, up to 16 kch.,

(pulsars, spectroscopy, continuum, spectropolarimetry).

Zoom modes (< 0.25 kHz res).

• VLBI backend: DBBC + MK-V recorder; RFI monitoring;



W3(OH) at 6.7 GHz with SRT: OTF continuum imaging and

spectroscopy of methanol maser line at increasing spectral resolutions

=30 kHz

=3.8 kHz

=1 kHz

=0.25 kHz

2 deg

Backends:

- Total power for mapping;

- XARCOS for spectra;

Credit: SRT Astronomical

Validation Team (AV)

Methanol maser



• Egron et al., Single-dish and VLBI observations of Cygnus X-3 during the 2016

giant flare episode, MNRAS, 2017, accepted;

See also http://www.srt.inaf.it

Science with SRT, published papers:

• Egron et al., Imaging of SNR IC443 and W44 with the Sardinia Radio Telescope

at 1.5 GHz and 7 GHz, MNRAS, Vol. 470, Issue 2, p.1329-1341, 2017;

• Govoni et al., Sardinia Radio Telescope observations of Abell 194 the intra-

cluster magnetic field power spectrum, A&A, 2017, 603, A122;

• Sanna et al, Planar infall of CH3OH gas around Cepheus A HW2, A&A, 2017,

in press;

• Murgia et al, Sardinia Radio Telescope wide-band spectral polarimetric

observations of the galaxy cluster 3C129, MNRAS, Vol. 461, 4, p.3516-3532, 2016;

• Prandoni et al, The Sardinia Radio Telescope: From a Technological Project to a

Radio Observatory, A&A, 2017, in press;



Status and perspectives of SRT project

• Six-month Early Science Program as single dish completed in Aug. 2016 with:

- L-P Band, C-Band and K-Band multibeam receivers;

- Backends: Roach2-based (2 GHz BW, 7 beams full-Stokes), VLBI,

total power, XARCOS (spectroscopy), DFB and Roach1 for pulsars;

• VLBI observations (part of EVN and RadioAstron);

• First scientific results being published;

• Refurbishment of the primary dish active surface completed in August 2017;

• Moving to new site infrastructures: control room, equip. room, visitor center, etc.

• Developing new Front-Ends, Back-ends and annexed hardware/software;

• ASI observed the grand finale of Cassini mission with X-band receiver in Sept. 2017;

• Technical and scientific recommissioning started end of Sep. 2017;

• New early science program in Autumn 2018 (stress test);

• Opening observation to international community in guest observer mode: early 2019;



Two multibeam receivers under development:

Q-Band (33-50 GHz) 19-beam

receiver for Gregorian focus

S-Band (3.0-4.5 GHz) 7-beam

receiver for primary focus



Vivaldi arrayPHAROS2: Demostrator of cryogenic C-band (4-8 GHz) Phased Array

Feed (PAF) of Vivaldi antennas with digital beamformer

Upgrade of PHAROS PAF, which was based on

analog beamformer;

Under development in the framework of the

PAF Advanced Instrumentation Program for

SKA;

Technology demonstrator project cooperated by

an international collaboration that includes

INAF, UMAN, ASTRON, OSO, UMalta;

To be mounted at Lovell telescope, Jodrell

Bank Observatory, UK;

INAF is developing the Warm Section, the IFoF

signal transportation and iTPM digital

beamforming of PHAROS2;

- 220 elements Vivaldi array;

- 24 Low Noise Amplifiers;

- 20 K cooling;

- 24 elements form four beams; Building up experience on system hardware and

software to allow developing a PAF for SRT;



Thank you !

http://www.srt.inaf.it

Status attuale e prospettive future del Sardinia Radio ... · Status attuale e prospettive future...

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