MASTERs of the Universe

SALT follows up on optical transients

Following its installation at Sutherland in late Dec 2014, the MASTER-SAAO node of the optical transient detection network has been busy discovering new optical transients. This is the first general transient detection system to be installed at SAAO, allowing for the rapid detection and followup of "things that go bump in the night".  

The MASTER-SAAO facility

So far 27 new optical counterparts have been discovered, including 19 cataclysmic variables (CVs), 2 supernovae and 6 currently unclassified transients. In addition, several Gamma Ray Burst (GRB) follow-up observations were conducted with MASTER, following triggers (e.g. from the SWIFT satellite), leading to the identification of optical counterparts and the determination of the afterglow decay curves for two of them, and upper limits for the rest. 

As part of a SALT Directors Discretionary Time program, snapshot RSS spectroscopic observations were undertaken of three MASTER SAAO transients in order to optically identify them. They were spectroscopically identified (and the results published in Astronomers Telegrams) to be a Dwarf Nova declining from an outburst (Atel #7165), a flaring FSRQ (Flat Spectrum Radio Quasar) blazar, at a redshift of 0.9 (Atel #7167), and an eclipsing magnetic CV, with a 2.1 h orbital period (Atel #7169). The latter was determined from follow-up photometry on the SAAO 1.9-m and 1.0-m telescopes using the high-speed SHOC cameras. This was conducted during a campaign of CV photometry undertaken by UCT PhD students Hannes Breytenbach and Mokhine Motsoaledi, together with John Thorstensen and undergaduate students visiting from Dartmouth College (a SALT partner), who were here in South Africa as part of a Foreign Study Program in Astronomy.

 

 SALT RSS spectrum (1100s) of the flaring FSRQ Blazar J141922.56-083831.7, with a possible MgII 2798Å emission line at redshift z = 0.903 (Atel #7167).

The Future:

During 2015 we hope to improve the efficiency of automating SALT Target of Opportunity (ToO) observations following from transient alerts (from MASTER and other sources). The new SAAO robotic 1.0-m telescope, expected to become operational during 2015, will also have an important role in followup work. Once MeerLICHT is installed (also later in 2015), there will  be an additional transient detection system at Sutherland, slaved to MeerKAT in order to catch optical counterparts of radio transients.