Observations of Optical Transients and ToOs at SAAO & SALT

David Buckley SALT Scientist

SAAO

Collaborators:

M. Boettcher, J.B. Breytenbach, R. Britto, S. Chandra, E. Gorbovskoy, A. Kniazev, M. M. Kotze, V. Lipunov, A. Moin, M. Motsoaledi, S. Potter, S. Razzaque, K.P. Singh, P. Woudt

1/25/16

University of Canterbury 2

SAAO Observing site - Sutherland

• until 2005 (SALT), largest telescope was 1.9-m• since 2002 have added 6 telescopes of 1.0 - 1.6m• numerous smaller aperture robotic telescopes with specific missions (e.g. extra-solar planets) and most recently, transient detection (MASTER)

19 telescopes: 0.04m (KELT) – 10m (SALT)

Many international facilities hosted

SALT

One of the “Big Five”: Segmented Mirror Telescopes

• Keck I (1993) & Keck II (1996): Hawaii, USA

• HET (1999): Texas, USA• SALT (2005): South Africa• GRANTECAN (2009): Canary Islands,

Spain

These telescopes currently have the largest light grasp

New paradigm in design has been pioneered bythe HET in Texas.

SALT First-Generation Science Instruments

• Instruments chosen to give SALT a wide range of capabilities

• Ensure competitiveness with niche operational modes– UV, Fabry-Perot, high-speed, polarimetry

• Take advantage of SALT design and modus operandii• Nominally budgeted for 3 “first generation” instruments• First two (‘first light’) instruments:

– SALTICAM: a sensitive “video camera” (up to ~15 Hz)– Robert Stobie Spectrograph (RSS):a versatile imaging

spectrograph – Both installed in 2005

• Last one, a fibre-fed High Resolution Spectrograph– Delivered and installed in Sep 2013– Science Verification through to Apr 2014– Now fully operational

An example: a light curve of an eclipsing magnetic CV (Polar) taken with SALTICAM

Ingress/Egress = 1.2 to 1.5 sec

Each data point a 0.1 sec exposure

First SALT Science:Example of high time resolution

photometry

Polars: Ideal ASTROSAT Multiwavelength Targets

Most of the energy from these systems is a result of accretion

3 main components to the SEDs:

cyclotron radiation from accretion column

hard X-ray emission, also from accretion column post-shock

soft X-ray emission, from heated surface of primary

Beuermann (1998)

Observing With SALT• 100% queue scheduled service

observing• Variety of instruments/modes• Rapid instrument changes and

mode configurations• Scheduling allows for synoptic

monitoring at difference cadences• Targets of Opportunity can be done

at short notice• Ideal for followup of transients

Examples of Successful Transient Observations1. Rapid Supernova Identification and Follow-up With SALT

PI: Robert Fesen (Dartmouth)A Target of Opportunity (ToO) campaign to classify nearby supernova candidates soon after they are discovered. Supernovae of interest may be monitored with additional follow-up spectra. The program is straightforward with rapid turn-around between initial observations and published identifications.

SALT observation of the Gamma Ray Burst GRB 060605

SALT Observations ~8 hours after alert• MSSSO (Australia) obs. when V ~ 15• SALT obs. at V ~ 21• Confirmation of Lyman break galaxy host

Examples of Successful Transient Observations2. Gamma Ray Burst Afterglows

Simultaneous ToOs of Xray transients: GX 339-4(Marissa Kotze & Phil Charles)

Looking for evidence of reprocessing in X-ray flares

Examples of Successful Transient Observations3 . X-ray transients & Low Mass X-ray Binaries

Other Examples of SALT ToO Science:demonstrating queue scheduling & quick reaction ability

Cir X-1: periastron passage (Schurch et al)

Coordinated with radio (KAT-7) observations

(Charles, Maccarone, et al)

(Odendaal et al)

RX J0513.9-6951: Transient SSS in LMC

(Odendaal et al)

CAL83

New Transient Observation Opportunities

• First local optical transient detection system installed at SAAO in Dec 2014o MASTER-SAAO node (2 x 0.4m; 4 – 8 sq ° FoV) o Russian led network (now with nodes in Argentina and Canaries)o No longer reliant on alerts from external transient detection systems

(e.g. at other longitudes)

MASTER details

• WIDE field MASTER-II (D=400mm)• 8 sq.deg or 4 sq. deg in 2 filters

v = 20 per 60s exp • Can measure Stokes Q, U with pol.

filters

• Robotic wide-field camera

VWF• 1000 square degrees , V= 12 in 1 sec exp• Coaligned with MASTER II telescopes

MASTER’s Aims

• Discovery of new optical transients

• Followup of transient alerts from other multiwavelength facilities– GRBs (e.g. within ~100s of SWIFT)– Blazar flares (e.g. FERMI)

– Neutrino events (e.g. ANTARES)– Gravitational wave events (e.g. LIGO)

– Exoplanets– Supernovae

• Solar Systems transients– Asteroids

– Comets

• Monitoring of transient events– e.g. V442 Cyg polarimetry

– Blazar flare evolution– CV outbursts

MASTER Alerts• All MASTER Optical Transient detections published in Atels• Website list all MASTER transients and includes images,

coordinates, amplitudes and sometimes colors or polarization properties (see http://observ.pereplet.ru/MASTER_OT.html )

• Links for GCN and other relevant websites

MASTER contributions to transient alerts in Astronomer’s telegrams

2013-2014

Swift

MASTERFermi

INTEGRAL

Chandra

Ломоносовские чтения, 2015

MASTER Sky Coverage

• Whole sky (N & S)• Including Galactic Plane (but lower priority)• MASTER-SAAO coverage:

– +30° > Dec > -90° in survey mode

– To northern limit (~40°) for followup

# CCD images

The MASTER System

 MASTER (total) CRTS (total) MASTER-SAAO SSS MLS CSS

      (Sutherland, South Africa

(Siding Spring,

Australia)

(Mt Lemon, USA) (Catalina, USA)

Tel. Diameter (m)     2 x 0.4 0.5 1.5 0.7

Exposures  3 x 60 (grey/bright)3 x 180 (dark) 4 x 30  3 x 60 (grey/bright)

3 x 180 (dark)4 x 30 

4 x 30 

4 x 30 

FoV (deg2) 42 13.3 4 4 1.1 8.2

Area/night (deg2) ~5000 ~2500 (?) 400-500

Limiting V mag 18-20 22 19.8 (dark)18.8 (grey)

Cadence 10 – 15 days 7 – 10 days Not operating

• MASTER II system compared to Catalina Real Time Survey– Cadence for any given field ~7-10 days– SSS stopped operations in 2013

MASTER-SAAO - installed and commissioned in < 3 weeks by late December 2014Over 200 new Optical Transients discovered, and 143 in the first ~9 months with following breakdown:• 109 DNe with m > 2m)• 1 polar• 1 novalike• 20 SNe• 4 LPVs• 3 flare stars • 2 GRB optical counterparts• 2 comets• 1 anti-transient (VY Scl novalike)

Plus followup observations of othertransient alerts: 7 blazar flares many asteroids

MASTER OT J141922.56-083831.7 bright blazar flare

MASTER-Kislovodsk auto-detection system discovered OT on 2015-02-21.98773 UT, m =14.6 (Atel 7133)Blazar flare was observed at SALT (DDT) reported in Atel 7167

If em line is MgII →z = 0.9significantly polarized

MASTER OT J141922.56-083831.7 bright blazar flare

Modelling underway (Sunil Chandra& Richard Britto)

GRB 141225A: First MASTER-SAAO GRB detection GCN Circular #17237

MASTER-SAAO was automatically pointed to the Swift alert (33 sec after Swift notice time) and to Fermi GRB 141225A

~ 0.76+-0.10 upto to 300s~ 1.51 from 400s to 1500s ~1 mag depression at 329 sec.

Limit to 22.3

GRB 150301B (GCN Circular 17518; 1 Mar)Second detection • at m= 15.3• weather RH precluded an attempted SALT observation (also no auto-alert)• ESO VLT spectroscopy (X-SHOOTER), 5 hours after the burst, at R = 21 • several absorption features (FeII, MgII, MgI), • redshift of 1.52.

MASTER Detection & Followup Capabilities

• MASTER can go as deep as V ~22• As demonstrated when searching for GRB afterglows

20 co-added 180s exp (1h total) filter-less exposures resulted in an upper limit determination of ~22.3, the faintest limit achieved of all MASTER nodes.

GRB150301B:Faded from 15.5 – 19 in 1100s~; 8% polarized

V404 Cyg: detection of polarization variablilty

MASTER (northern nodes) have detected polarization on two occasions, during dips.

Classification of MASTER OT J061451.70-272535.5 as an eclipsing polar

• Discovered Feb 20 at m = 18 transient• Followed up photometrically • Light curves show eclipses and stream

obscuration, typical of Polar• Orbital period = 2.1 h

Classification of MASTER OT J061451.70-272535.5 as an eclipsing polar

• SALT DDT confirms mCV spectrum (strong HeII)• ATel #7169

New MASTER CVs

• MASTER has discovered 1000 optical transients (since 2011; ~4 years)

• 530 new CVs discovered by MASTER network

• Compare to 705 new CVs from CRTS (+150 known) in ~5 years (Nov 2007 – Aug 2012; Drake et al. 2014)

• MASTER-SAAO has discovered 111 CVs– Mostly DNe detected with amplitudes:2 – 3 mags: 30%3 – 4 mags: 20%4 – 5 mags: 30%>5 mags: 20%

• Consistent with CRTS results

CRTS CVs

MASTER CV Distribution

• For 530 CVs (detection threshold >2m amplitude from reference frame)

CRTS CV Distribution

• For 855 CVs (detection criteria m > 0.6m in 3 out of 4 images)

New Transient Observation Opportunities

• MASTER will be joined soon (later in 2015) by MeerLICHT (0.65 m; 2 sq ° FoV)o Joint Dutch-SAAO ventureo Optical monitoring of MeerKAT fieldso Correlate with radio transients

New Transient Observation Opportunities

• Plan to follow-up selected transients with SALT and new SAAO robotic facilitieso MONET 1.2m (German-SA bilateral project)o new SAAO 1.0 m robotoico instruments including CCD and high speed

EM-CCD cameras and spectrograph(s)

SAAO Telescope “farm” on the Sutherland plateau

(Six 1 – 1.6m telescopes since 2002)

MASTER(2 x 0.4m)

MeerLICHT(0.65m)

Robotic 1-m

MONET (1.2-m)

FINAL REMARKS

• SALT well suited to ToOs and followup of transients (optical, X-ray, gamma ray), including SNe, GRBs (when caught early enough), CVs, blazar flares, X-ray transients

• New transient detections systems at Sutherland (MASTER-SAAO & soon MeerLICHT)

• • New follow-up facilities at SAAO coming on-line soon (1-m

robotic, MONET), plus auto-alert/scheduling system

• MASTER alerts and followups can provide experience ahead of data deluges from other facilities (e.g. LSST)

• Multi-wavelength opportunities (e.g. now with: KAT-7, HESS, X-ray missions; future with: MeerKAT, HESS, ASTROSAT… SKA, CTA…)