Transcript richichi-iccp9 - Global Observatory Network for Solar System

Andrea Richichi , Puji Irawati, B. Soonthornthum (NARIT)
V. Dhillon (Sheffield), T.R. Marsh (Warwick)
"Global Observatories and TimeDomain Astrophysics“
ICCP9, Singapore - January 9, 2015
Thai National Telescope (TNT)
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2457m elevation, Nov-Apr dry season
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2.4m alt-az Ritchey-Chretien, f/10
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Two Nasmyth foci
18 34 25 N, 98  28  56  E
Altitude: 2457m
• Nasmyth 1 with derotator, 4 ports,
autoguider, fiber feeds
• imagers and spectrographs, visitor
instruments
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Erected 2012, Inaugurated 2013
• First official season (Cycle 1) started in
November 2013, Call for Proposals, TAC
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Cycle 2 currently in progress
Also operated by NARIT:
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0.5m f/6.5
• 60cm PROMPT8 robotic telescope at
Cerro Tololo
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The Thai Southern Hemisphere Observatory (PROMPT8)
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Telescope1: Planewave CDK24 (24" f/6.8)
Telescope2: Takahashi FSQ 106 (refractor telescope)
Mount: Astro-Physics 3600GTO (with Precision Encoder)
CCD1: Apogee U42 (imaging, 2048 x 2048, back illuminated)
CCD2: Apogee U47 (polarimeter, 1024 x 1024, back illuminated)
Dome: 16ft Astrohaven clamshell
Regional Public Observatories
The project was approved in March 2009. Six observatories will be
established spreading over different regions of the country. First
two are operative. 0.5-m class with CCDs, facilities.
ULTRASPEC @ TNT
Built by Sheffield/Warwick/UKATC
(Vik Dhillon, Univ of Sheffield &
T.R. Marsh, Univ of Warwick)
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Frame-transfer EMCCD
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Det previously used on ESO3.6m and NTT
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MoU signed with NARIT in 2012
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Custom optics (0.45”/pixel, 7.7’ FOV)
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2 filter wheels, total of twelve options
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At TNT: g’=24 in 30 min @ SNR=10 (TBC)
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Subframe readouts up to 400+ Hz
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Installation Aug 2013
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Commissioning Nov 2013
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~25 nights GTO per year
ULTRASPEC EMCCD
Frame-Transfer Electron Multiplying CCD
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0.01s Time Resolution
full frame
switchable gain
low read-out noise
ULTRASPEC (Dhillon et al)
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Gain register
Secondary electrons are generated via
an impact-ionization process
Two outputs: normal and avalanche
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ULTRASPEC Readout Modes
Multiple Windows
Drift-Mode
By reducing the window size, readout times
are considerably shortened: e.g., from 13s
full-frame down to ~0.2s for 1002 pixels
Drift Direction
Mask
E.g., 16x16 pixels with 2x2 rebin
leads to ~6ms DIT, with <1 ms overheads.
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Science with ULTRASPEC@TNT
Results
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Eclipsing binaries
Cataclysmic Variables
White dwarf binaries
Circumbinary planets
Variable stars in clusters
Lunar Occultations
Trans-Neptunian Objects
Our collaborators
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Time of Minimum of Eclipsing Binaries
DW UMa, nova-like, mag ~14
28-Dec-2013
(BIMA proposal: Irawati, Sarotsakulchai, Richichi et al)
DW UMa
Reference
g’ filter, multiple window mode, DIT 3.5s
accurate GPS timing
online data reduction with 1 field reference star
with ULTRACAM pipeline
Fast Photometry of Cataclysmic Variables
g’ filter, subwindow mode, Δt=2.6s
raw data reduction with 1 field reference star
with ULTRACAM pipeline v9.11
approximate photometry from ETC calculator
UZ For (polar)
28-Dec-2013
(EB proposal: Irawati, Slowikowska, Richichi,
Soonthornthum, Zejmo)
Class of binary stars containing a white dwarf and a
low mass companion star in a close orbit (1 -10 hrs
period). Exotic phenomena: outbursts, superhumps,
quasi periodic oscillations, flickering, mass transfer
Credit: K. Smale
Fast Photometry of Cataclysmic Variables
UZ For (polar)
28-Dec-2013
g’ filter, subwindow mode, Δt=2.6s
raw data reduction with 1 field reference star
with ULTRACAM pipeline v9.11
approximate photometry from ETC calculator
(EB proposal: Irawati, Slowikowska, Richichi,
Soonthornthum, Zejmo)
High time resolution allows us to study
details of the system and of the individual
stars. Follow-up with accurate GPS timings
can prove the presence of an exoplanet from
C-O residuals (below, from Perryman et al
2001)
hot spots
extended emission
flickering
Search for circumbinary planets
HU Aqr (polar CV)
28 -Apr-2014
r’ filter, 4.3s
proposal: Irawati, Richichi, Slowikowska
& ULTRASPEC GTO
Some points between Nov 2013
and Apr 2014 obtained from TNT
Papers including TNT observations:
Bours et al. 2014, MNRAS 445, 1924
Gozdziewski et al. 2014, in press
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Flickering in Cataclysmic Variables
RW Sex (nova-like CV)
11-Jan-2014
(proposal: Irawati, Richichi, Dhillon, Gaensicke)
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Low-frequency Flickering (minutes)
High-frequency Flickering (seconds)
g’ filter, subwindow mode, DIT=1.35s
raw data reduction with 1 field reference star
with ULTRACAM pipeline v9.11
approximate photometry from ETC calculator
Prominences in PCEBs
g’, DIT 59s
Irawati et al. 2015, in prep
Long-term post-eclipse dips!
Photometric evidence of prominences??
Collaborators:
T. Marsh, M. Bours – UK
S. Parsons – Chile
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Occultation Light Curve of HR 7072
HR 7072 is a V=6.5 mag star in Sagittarius, which is known to be a binary (Kui 88).
It was occulted in the night of 20-21 April, 2014 and the event was recorded at
4h44m AM at the Thai 2.4m National Telescope with the ULTRASPEC instrument.
32x32 pixels
with 2x2 rebin
Time Resolution = 11.3 ms
H filter (94Å width)
airmass = 1.3, seeing 1.0”
Reappearance from behind
the Moon’s Limb
Preliminary Analysis of the Light Curve
Spike due to diffraction
by the Moon’s edge.
Measured Signal
Separation 281 ms → 0.09”
Star A
Flux
𝐴
= 3.4
𝐵
Star B
Time in milliseconds
Occultation Light Curve of IRC +20090
HR 7072 is HD 285977, a V=9.2 mag late-type star. It is quoted as K spectral type,
but has been suspected to be a Mira. Chandrasekhar & Tej (2000) measured its
angular diameter by a LO to be 3.7±0.3 mas. It was occulted in the evening of 2nd
January, 2015 at the Thai 2.4m National Telescope with the ULTRASPEC instrument.
16x16 pixels
with 2x2 rebin
Samping = 6.8 ms
Narrow Infrared Filter
λ=860 nm Δλ=20 nm
Observing Team: P. Irawati, A. Richichi (NARIT), O. Tasuya (CMU)
Telescope Support: NARIT Operations Department
Preliminary Analysis of the Light Curve
Point Source best fit : 2 =0.8
φ=3.7 mas best fit : 2 =0.8
SNR = 11.5 ... not sufficient to measure the angular size 
Centaur object (10199) Chariklo
Stellar occultation by Trans-Neptunian Object
(proposal: Richichi, Sicardy,
Braga-Ribas)
r’, DIT 3.3s
15deg elevation,
Vignetting > 30%
Stellar occultation by the
Trans-Neptunian Object 2003 AZ84
ULTRASPEC @ 2.4-m TNT on Nov 15, 2014
Observer
Star magnitude ~14
Clear Filter, 0.8 s sampling, ~2’x2’ field
Observers: Irawati, Richichi (NARIT)
(collaboration with B. Sicardy & F. Braga-Ribas)
mid-occultation ~ 17:58 UT,
(several minutes later than predicted)
duration ~50 s, drop ~ 4 mag
raw data shown
Also observed from China & Japan
Conclusions and Prospects
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The Thai 2.4m National Telescope is
well equipped to achieve high time
resolution, including instruments such
as ULTRASPEC.
With ULTRASPEC, sampling as high as
~400Hz can be reached on small
windows. The sensitivity is close to
g’~18 mag in 1s with SNR 20.
Observations have started in
November 2013, with numerous
results that encompass commonenvelope binaries, transits, eclipses,
flickering, and lunar occultations.
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NARIT is part of the SEAAN and has
close links with several institutes in
East and South-East Asia.
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Researchers from other institutes are
warmly invited to collaborate with
NARIT researchers.
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Opportunities for students (thesis
projects, internships)
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Cycle 3 will run from Nov’15 to Apr’16
(northern Thai dry season). A Call for
Proposals is foreseen in June 2015.
Due to its geographical position and
aperture, the TNT 2.4m telescope
provides unique opportunities for high
time resolution in South-East Asia
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