Astronomical
Validation of the SRT
Simona Righini, INAF-IRA – TD (Tecnologo III)
AV Team
¡  PS: Isabella Prandoni
¡  Co-PS: Matteo Murgia, Andrea Tarchi, Alessandro Orfei, Gianni Comoretto
¡  ~35 people covering technical/astronomical expertise (IRA – OAC – Arcetri):
Nichi D'Amico
Andrea Orlati
Simona Righini
Roberto Ricci
Sergio Poppi
Alberto Pellizzoni
Federica Govoni
Tonino Pisanu
Andrea Melis
Carlo Migoni
Silvia Casu
Marta Burgay
Alessio Trois
Antonietta Fara
Paola Castangia
Valentina Vacca
Maria Noemi Iacolina
Ignazio Porceddu
Pietro Bolli
Alessandro Corongiu
Alessandra Zanichelli
Carlo Stanghellini
Francesco Nasyr
Delphine Perrodin
à Pulsar, Galactic & Extra-galactic, etc.
à Continuum, Line, Mapping, VLBI, etc.
à SW, Receivers, Backends, RFI, etc.
Francesco Gaudiomonte
Giuseppe Valente
Elise Egron
Caterina Tiburzi
Alessandro Ridolfi
Fabrizio Massi
Raimondo Concu
Marco Bartolini
Marco Buttu
Daria Guidetti
Francesca Loi
Matteo Bachetti
Sardinia Radio Telescope
Largest Italian radio telescope (64 m)
Quasi-Gregorian system with shaped surfaces
Multiple focal positions (P, G, 4 BWG):
àup to 20 receivers in frequency agility
Active Surface: 1008 panels, 1116 remotely
controlled electro-mechanical actuators
www.srt.inaf.it
Receivers and back-ends
310-420 MHz
1.3-1.8 GHz
TP: analog Total Power
Dual-band
7x2 outputs, 2 GHz BW
XARCOS: Digital
Spectrometer
5.7-7.7 GHz
Mono-feed
8 outputs, 60 MHz BW,
4096 channels
DBBC2 (1 GHz, 4 IFs) + Mark5C
(VLBI) + SW Corr (DIFX)
18-26.5 GHz
Multi-feed
7 elements
DFB: Digital Spectrometer (pulsar)
(ATNF Pulsar Digital Filter-Bank)
1 GHz BW, up to 16384 chan
ROACH boards: 2x512 MHz/1x1024 MHz
SRT Project Status
Opening: Sept. 30, 2013
Buildings: somewhere in 2015
Telescope Commissioning (closed: Oct. 2013)
Advanced technical activities and precursors (started: Jan. 2014)
“Fine-tuning”, integration of sub-systems (e.g. derotator), commissioning of additional
backends (DFB, XARCOS, etc.), metrology, site monitoring, etc.
Astronomical Validation (running in parallel, usually in evenings – 16-24)
AV Goals
Last phase before first science-driven astronomical observations
(shared-risk, early science)
¡  Goal 1: characterization of the SRT astronomical performance in
all the standard observing modes; identification of technical
problems and/or limitations;
¡  Goal 2: transformation of the instrument into a real Observatory
(HW/SW development, observing/analysis tools, cook-book, etc.);
¡  Goal 3: maximization of science exploitation when made available
My main contributions (@ Medicina as well)
Commissioning
and AV
Tests & Tools
Calibration
campaigns
Software
Development
Outreach
Documentation
(e.g. User’s
guides)
RFI
(PRIN)
(By the way…)
Fine Tuning and AV
AV “Grey-zone” TP tests
Sort of “bridge” tests linking technical commissioning and “pure AV”.
Goals: characterization of the TP backend, verification of On-The-Fly scans pointing accuracy
and maximum exploitable speed, assessment of basic parameters of the SRT continuum
capabilities, etc.
Measurement of the confusion noise:
~0.2 mJy/beam @ 7.3 GHz
RMS noise (mJy/beam)
Source amplitude (counts)
Verification of the
back-end linearity range
Peak level (counts)
Credits: S. Righini
Time (s/beam)
AV Software Tools
Observing with SRT:
• ETC: SRT Exposure Time Calculator
Zanichelli et al.
• CASTIA: Source Visibility
>30 telescopes (incl. EVN), on line
• ScheduleCreator
Vacca, Iacolina et al.
Bartolini et al.
Nuraghe SD Operations (TP/XARCOS)
• SEADAS
Corongiu et al.
Interface for Pulsar Obs. (DFB/ROACH)
Data Monitoring/Handling:
•  Cross-Scan Quick-Look/Reduction
Righini et al.
•  SDI: SD multi-feed Imager (OTF)
Pellizzoni et al.
•  RFI monitoring (DBBC)
Melis et al.
•  RFI detection/excision
Ricci et al.
•  Format Converters
Trois et al.
FITS to CLASS, etc.
Available on-line/SRT site
Single-Dish Imager
Imaging tests on SNR 3C157/IC 443
VLA 330 MHz
64”x74” resolution
Medicina 5 GHz
6.4’ res.
SRT 7 GHz
2.8’ res.
June 2014
TP
(Hewitt et al. 2006)
(Pellizzoni et al. 2013)
Credits: SDI Team - A.Pellizzoni, E.Egron,
M.N.Iacolina, S.Righini, A.Trois, V.Vacca
SRT 7 GHz
2.8’ res.
(test)
ROACH
High Dynamic Range Imaging
ADVANCED TEST:
Observations with TP (C Band) to test/debug beam deconvolution procedures based on
Imaging SW SCUBE (Govoni et al.): 300 maps of 3C147
Precursor: deep beam pattern measurements in various Elevation ranges
3C147: Beam Model
Credits:
M. Murgia, F. Govoni, S.Poppi, V.Vacca, P.Castangia, A.Tarchi
High Dynamic Range Imaging
Beam Model
3C147: Dirty Image
3C147: Cleaned Image
Beam reconstruction and shapelet modeling are effective!
è Dynamic Range ~ 7000 (and counting…)
Credits:
M. Murgia, F. Govoni, S.Poppi, V.Vacca, P.Castangia, A.Tarchi
AV Summary
VALIDATED - CLOSE TO VALIDATION:
ü VLBI Operations: first session (in shared risk) is ongoing
(EVN+RadioAstron) L, C, K
ü LEAP Operations: L-band/Roach (close to ready)
ü Single Dish: Pulsar C-band Observations: TP and DFP folding
mode; continuum TP observations: C-band, incl.
imaging; K-band-single
IN PROGRESS:
ü Single Dish K-band-multifeed/imaging: Continuum TP
ü Single Dish Spectroscopy: single/multi-feed: XARCOS,
ROACH boards
ü Single Dish Pulsar search mode
CAVEAT: logistics, technical support (shifts),
manpower…