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Andrea Richichi, Puji Irawati, B. Soonthornthum (NARIT) V. Dhillon (Sheffield), T.R. Marsh (Warwick) "Global Observatories and Time- Domain Astrophysics“

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Presentation on theme: "Andrea Richichi, Puji Irawati, B. Soonthornthum (NARIT) V. Dhillon (Sheffield), T.R. Marsh (Warwick) "Global Observatories and Time- Domain Astrophysics“"— Presentation transcript:

1 Andrea Richichi, Puji Irawati, B. Soonthornthum (NARIT) V. Dhillon (Sheffield), T.R. Marsh (Warwick) "Global Observatories and Time- Domain Astrophysics“ ICCP9, Singapore - January 9, 2015

2 18   N, 98   E Altitude: 2457m 2457m elevation, Nov-Apr dry season 2.4m alt-az Ritchey-Chretien, f/10 Two Nasmyth foci Nasmyth 1 with derotator, 4 ports, autoguider, fiber feeds imagers and spectrographs, visitor instruments Erected 2012, Inaugurated 2013 First official season (Cycle 1) started in November 2013, Call for Proposals, TAC Cycle 2 currently in progress Thai National Telescope (TNT) 2 Also operated by NARIT: 0.5m f/6.5 60cm PROMPT8 robotic telescope at Cerro Tololo

3 1.Telescope1: Planewave CDK24 (24" f/6.8) 2.Telescope2: Takahashi FSQ 106 (refractor telescope) 3.Mount: Astro-Physics 3600GTO (with Precision Encoder) 4.CCD1: Apogee U42 (imaging, 2048 x 2048, back illuminated) 5.CCD2: Apogee U47 (polarimeter, 1024 x 1024, back illuminated) 6.Dome: 16ft Astrohaven clamshell The Thai Southern Hemisphere Observatory (PROMPT8)

4 Regional Public Observatories The project was approved in March Six observatories will be established spreading over different regions of the country. First two are operative. 0.5-m class with CCDs, facilities.

5 Sept 22, 2013Sept 22, 2013 WS, Tatranská Lomnica, Slovakia WS, Tatranská Lomnica, Slovakia 5 TNT Built by Sheffield/Warwick/UKATC (Vik Dhillon, Univ of Sheffield & T.R. Marsh, Univ of Warwick) Frame-transfer EMCCD Det previously used on ESO3.6m and NTT MoU signed with NARIT in 2012 Custom optics (0.45”/pixel, 7.7’ FOV) 2 filter wheels, total of twelve options At TNT: g’=24 in 30 SNR=10 (TBC) Subframe readouts up to 400+ Hz Installation Aug 2013 Commissioning Nov 2013 ~25 nights GTO per year

6 ULTRASPEC EMCCD 6 Frame-Transfer Electron Multiplying CCD 0.01s Time Resolution full frame switchable gain low read-out noise ULTRASPEC (Dhillon et al) Gain register Secondary electrons are generated via an impact-ionization process Two outputs: normal and avalanche

7 ULTRASPEC Readout Modes 7 Multiple Windows Drift-Mode Mask Drift Direction E.g., 16x16 pixels with 2x2 rebin leads to ~6ms DIT, with <1 ms overheads. By reducing the window size, readout times are considerably shortened: e.g., from 13s full-frame down to ~0.2s for pixels

8 8 Results Eclipsing binaries Cataclysmic Variables White dwarf binaries Circumbinary planets Variable stars in clusters Lunar Occultations Trans-Neptunian Objects Our collaborators Science with

9 Time of Minimum of Eclipsing Binaries DW UMa, nova-like, mag ~14 28-Dec-2013 (BIMA proposal: Irawati, Sarotsakulchai, Richichi et al) g’ filter, multiple window mode, DIT 3.5s accurate GPS timing online data reduction with 1 field reference star with ULTRACAM pipeline Reference DW UMa

10 Fast Photometry of Cataclysmic Variables UZ For (polar) 28-Dec-2013 (EB proposal: Irawati, Slowikowska, Richichi, Soonthornthum, Zejmo) 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 Credit: K. Smale 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

11 Fast Photometry of Cataclysmic Variables UZ For (polar) 28-Dec-2013 (EB proposal: Irawati, Slowikowska, Richichi, Soonthornthum, Zejmo) 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 hot spots extended emission flickering 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)

12 12 Search for circumbinary planets r’ filter, 4.3s Some points between Nov 2013 and Apr 2014 obtained from TNT HU Aqr (polar CV) 28 -Apr-2014 proposal: Irawati, Richichi, Slowikowska & ULTRASPEC GTO Papers including TNT observations: Bours et al. 2014, MNRAS 445, 1924 Gozdziewski et al. 2014, in press

13 Flickering in Cataclysmic Variables RW Sex (nova-like CV) 11-Jan-2014 (proposal: Irawati, Richichi, Dhillon, Gaensicke) 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 Low-frequency Flickering (minutes) High-frequency Flickering (seconds)

14 14 Prominences in PCEBs g’, DIT 59s Long-term post-eclipse dips! Photometric evidence of prominences?? Irawati et al. 2015, in prep Collaborators: T. Marsh, M. Bours – UK S. Parsons – Chile

15 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 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 April, 2014 and the event was recorded at 4 h 44 m AM at the Thai 2.4m National Telescope with the ULTRASPEC instrument. 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 April, 2014 and the event was recorded at 4 h 44 m AM at the Thai 2.4m National Telescope with the ULTRASPEC instrument.

16 Time in milliseconds Measured Signal Star B Star A Separation 281 ms → 0.09” Preliminary Analysis of the Light Curve Spike due to diffraction by the Moon’s edge.

17 16x16 pixels with 2x2 rebin Samping = 6.8 ms Narrow Infrared Filter λ=860 nm Δλ=20 nm Occultation Light Curve of IRC HR 7072 is HD , 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 2 nd January, 2015 at the Thai 2.4m National Telescope with the ULTRASPEC instrument. HR 7072 is HD , 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 2 nd January, 2015 at the Thai 2.4m National Telescope with the ULTRASPEC instrument. Observing Team: P. Irawati, A. Richichi (NARIT), O. Tasuya (CMU) Telescope Support: NARIT Operations Department

18 Point Source best fit :  2 =0.8 Preliminary Analysis of the Light Curve Point Source best fit :  2 =0.8 φ=3.7 mas best fit :  2 =0.8 Point Source best fit :  2 =0.8 φ=3.7 mas best fit :  2 =0.8 SNR = not sufficient to measure the angular size 

19 Centaur object (10199) Chariklo Stellar occultation by Trans-Neptunian Object r’, DIT 3.3s 15deg elevation, Vignetting > 30% (proposal: Richichi, Sicardy, Braga-Ribas)

20 Stellar occultation by the Trans-Neptunian Object 2003 AZ m TNT on Nov 15, 2014 Stellar occultation by the Trans-Neptunian Object 2003 AZ 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

21 Conclusions and Prospects 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 common- envelope binaries, transits, eclipses, flickering, and lunar occultations. Due to its geographical position and aperture, the TNT 2.4m telescope provides unique opportunities for high time resolution in South-East Asia NARIT is part of the SEAAN and has close links with several institutes in East and South-East Asia. Researchers from other institutes are warmly invited to collaborate with NARIT researchers. Opportunities for students (thesis projects, internships) Cycle 3 will run from Nov’15 to Apr’16 (northern Thai dry season). A Call for Proposals is foreseen in June


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