Southern African Large Telescope

Presentation of SALT capabilities given as part of the Open Skies South Africa China meeting at Nanjing Institute of Astronomical Optics & Technology

Transcript

1. Southern African Large Telescope Steve Crawford crawford@saao.ac.za @astrocrawford SALT Science Data Manager SAAO/SALT
2. SALT Observing Science with SALT SALT
3. SALT Observing Science with SALT Star moves E to W on sky Image moves W to E on the focal surface Centre of curvature at radius of primary mirror Spherical focal surface: 1/2 of primary mirror radius Tracker follows focus of star The Arecibo Concept Spherical Primary Based on HET FAST
4. SALT Observing Science with SALT Advantages of SALT Advantages •Economical •UV optimized •Entirely Queue based •Designed to explore the time domain •Optimized for observations of the LMC Limitations: •Constraints on observations •Mass limitations at Prime focus
5. SALT Observing Science with SALT SALTICAM Multi-mode imaging and acquisition camera. In full- frame mode, it has an 8x8’ FOV. In slotmode, high- speed photometry (20 Hz) can be performed over a smaller field of view. Darragh O’Donoghue
6. SALT Observing Science with SALT Robert Stobie Spectrograph Highlights of RSS: • UV Spectroscopy down to 3200 Ǻ • High throughput and resolution VPH gratings • Fabry-Perot Modes • Polarimetry • High Speed Ken Nordsieck, Ted Williams
7. SALT Observing Science with SALT
8. SALT Observing Science with SALT High Resolution Spectrograph High Resolution Mode Medium Resolution Mode Low Resolution Mode High Stability Fiber Diameter (arcsec) 1.56 2.23 2.23 1.56 Resolution 66800 37000 16200 66800 S/N~10 in 1800s exposure 16.5 17 18 15 PI: Ray Sharples
9. SALT Observing Science with SALT SALT Partners New collaborations sought South Africa is a 1/3 Partner
10. SALT Observing Science with SALT Using SALT 1.Proposing for Data -Two phase proposal process 2.Information added to the science database -Can be done on the day of the observations 3.Fully queue scheduled operations 4.Data Pipeline -Run at 10 am next day 5.Data Distribution -Raw data immediately; reduce data, same day
11. SALT Observing Science with SALT 11 PySALT v0.5 PIPETOOLS Tasks to automate running the pipeline PySALT is the Python/PyRaf software package for SALT data reduction and analysis. The next version of PySALT package includes: SALTRED Basic CCD data Reductions SLOTTOOLS Slotmode photometry And analysis tools SPECTOOLS Tools to provide wavelength and flux calibrated data FPTOOLS Fabry-Perot related software http://www.pysalt.salt.ac.za/ pyhrs Tools for the high resolution spectrograph
12. SALT Observing Science with SALT Long-Slit Reductions
13. SALT Observing Science with SALT Generalized Tools ccdproc: Astropy affiliated package for reducing optical/IR CCD data specreduce: Reduction software for data from optical spectrographs PySpectrograph: Models for optical spectrographs All code available on github and contributions welcomed! PyHRS: Reduction of HRS data polSALT: Reduction of polarimetric data
14. SALT Observing Science with SALT Normal science operations began in September 2011 after an extended commissioning period. Since first light, SALT has published over 180 papers. Science with SALT
15. SALT Observing Science with SALT Near Earth Asteroids Christou et al. 2012 Near Earth Asteroids
16. SALT Observing Science with SALT Eclipsing Binaries Possible detection of two giant extrasolar planets orbiting the eclipsing polar UZ Fornacis Potter et al. 2011, MNRAS, 416, 3
17. First Nature Paper
18. SALT Observing Science with SALT Supernova Follow-up 8 Cartier et al. arXiv:1609.04465v2 [astro-ph.SR] 14 Oct 2016 MNRAS 000, 1–17 (2016) Preprint 17 October 2016 Compiled using MNRAS L A TEX style file v3.0 Early observations of the nearby type Ia supernova SN 2015F R. Cartier1⋆, M. Sullivan1, R. Firth1, G. Pignata2,3, P. Mazzali4,5, K. Maguire6, M. J. Childress1, I. Arcavi7,8, C. Ashall4, B. Bassett9,10,11, S. M. Crawford9, C. Frohmaier1, L. Galbany12,13, A. Gal-Yam14, G. Hosseinzadeh7,8, D. A. Howell7,8, C. Inserra6, J. Johansson14, E. K. Kasai9,10,11,15, C. McCully7,8, S. Prajs1, S. Prentice4, S. Schulze3,16, S. J. Smartt6, K. W. Smith6, M. Smith1, S. Valenti7,8, and D. R. Young6 1Department of Physics and Astronomy, University of Southampton, Southampton, Hampshire, SO17 1BJ, UK 2Departamento de Ciencias Fisicas, Universidad Andres Bello, Avda. Republica 252, Santiago, Chile 3Millennium Institute of Astrophysics, Santiago, Chile 4Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK 5Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching, Germany 6Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN, UK 7Las Cumbres Observatory Global Telescope Network, 6740 Cortona Dr., Suite 102 Goleta, Ca 93117 8Department of Physics, University of California, Santa Barbara, CA 93106-9530, USA 9South African Astronomical Observatory, P.O.Box 9, Observatory 7935, South Africa 10African Institute for Mathematical Sciences, 6-8 Melrose Road, Muizenberg 7945, South Africa 11Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch, 7700, South Africa 12Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT PACC). 13Physics and Astronomy Department, University of Pittsburgh, Pittsburgh, PA 15260, USA. 14Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel 15Department of Physics, University of Namibia, 340 Mandume Ndemufayo Avenue, Pioneerspark, Windhoek, Namibia 16Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Vicuña Mackena 4860, 7820436 Macul, Santiago, Chile Accepted 2016 October 14. Received 2016 October 11; in original form 2016 May 25 ABSTRACT We present photometry and time-series spectroscopy of the nearby type Ia supernova (SN Ia) SN 2015F over −16 days to +80 days relative to maximum light, obtained as part of the Public ESO Spectroscopic Survey of Transient Objects (PESSTO). SN 2015F is a slightly sub-luminous SN Ia with a decline rate of ∆m15(B) = 1.35 ± 0.03 mag, placing it in the region between normal and SN 1991bg-like events. Our densely-sampled photometric data place tight constraints on the epoch of first light and form of the early-time light curve. The spectra exhibit photospheric C ii λ6580 absorption until −4 days, and high-velocity Ca ii is particularly strong at < −10 days at expansion velocities of ≃23000 km s−1. At early times, our spectral modelling with syn++ shows strong evidence for iron-peak elements (Fe ii, Cr ii, Ti ii, and V ii) expanding at velocities > 14000km s−1, suggesting mixing in the outermost layers of the SN ejecta. Although unusual in SN Ia spectra, including V ii in the modelling significantly improves the spectral fits. Intriguingly,we detect an absorption feature at ∼6800 Å that persists until maximum light. Our favoured explanation for this line is photospheric Al ii, which has never been claimed before in SNe Ia, although detached high-velocity C ii material could also be responsible. In both cases the absorbing material seems to be confined to a relatively narrow region in velocity space. The nucleosynthesis of detectable amounts of Al ii would argue against a low-metallicity white dwarf progenitor. We also show that this 6800 Å feature is weakly present in other normal SN Ia events, and common in the SN 1991bg-like sub-class. Key words: supernovae: general – supernovae: individual (SN 2015F) ⋆ E-mail: r.cartier-ugarte@soton.ac.uk (RC) 1 INTRODUCTION The uniformity of type Ia supernova (SN Ia) light curves allows them to be used as reliable distance indicators, providing crucial c ⃝ 2016 The Authors ArXiv:1609.04465 SALT
19. Polarimetry SN2016adj in Cen A
20. Deep MOS observations
21. SALT Observing Science with SALT GW170817 Abbott et al, McCully et al., Andreoni et al, Buckley et al. 2017
22. SALT Observing Science with SALT Future Instruments RSS Near-Infrared IFU Early 2019
23. SALT Observing Science with SALT Improvements to HRS HS pipeline : Current pipelines need improvement to reach <10 m/s accuracy Lack of exper^se in current SALT Astro Ops – new hires sought Laser Frequency Comb op^ons / contacts : Would currently be a unique capability on 10m class telescopes HRS High Stability Mode (exo-planets) Beijing 2017 SALT Instrumentation Projects S pipeline : Current pipelines need improvement to reach <10 m/s accuracy ck of exper^se in current SALT Astro Ops – new hires sought ser Frequency Comb op^ons / contacts : Would currently be a unique pability on 10m class telescopes HRS High Stability Mode (exo-planets) Beijing 2017
24. SALT Observing Science with SALT Transient Spectroscopic Facility • RSS upgrade (~20% more throughput) • RSS Slit IFU • Rapid follow-up (API for submitting single blocks) • High throughput spectrograph • Multiplexing the trackers?
25. SALT Observing Science with SALT Using SALT What is SALT especially good at? Telescope: Huge collecting power. Site: Skies are very dark (V ~ 22 mag/arcsec2). Seeing is modest. •  Diffuse low-surface-brightness spectroscopy very competitive. •  Objects above background observed very efficiently. •  Can change instruments and observing modes in seconds. •  Rapid reaction to ToOs. •  Some rare modes for large telescopes (FP, Pol, mixed modes, high-time resolution) •  SALT as a spectroscopic survey telescope. Most efficient programs are surveys with large pools of targets over the sky.
26. SALT Observing Science with SALT SALT Operations SALT Opera^ons Mode •  Fully queue-scheduled •  Partners allocate their own Yme –  P0, P1, P2, P3. Plus P4 filler •  Time can also be bought (approx $2000 / h) •  Recent Semesters Efficiency: –  99% completeness for P0 –  90% completeness for P1 –  75% completeness for P2 •  Observing Block Scoring Algorithms and Semester Simula%ons facilitate efficiency
27. Scientific Productivity Papers since the start of Science Operations
28. SALT Observing Science with SALT Moving Forward SALT is in full science operations producing a range of exciting results. With the small operations cost, full service mode, availability of reduced data, SALT is a cost effective observatory.
29. SALT Observing Science with SALT Transformational SALT Science Conference 2015 National Astrophysics and Space Science Programme SALT Collateral Benefits Program
30. SALT Observing Science with SALT Supernova Follow-up Eli Kasai (UCT/SAAO/AIMS)