POLISH SCIENCE WITH SALT in 2014
By Joanna Mikołajewska, N.Copernicus Astronomical Center, Warsaw, Poland
Papers published in 2014:
Hryniewicz, K., Czerny, B., Pych, W., et al: SALT spectroscopy of LBQS 2113-4538: variability of the MgII and FeII component, A&A 562, A34
Hajduk, M., Gładkowski, M., Soszyński, I.: Search for binary central stars of the SMC PNe, A&A 561, A8
Hajduk, M., van Hoof, P.M., Gęsicki, K. et al.: The evolving spectrum of the planetary nebula Hen 2-260, A&A 567, 15
Narloch, W., Kaluzny, J., Krzeminski, W. et al.: New observations of the old magnetic nova GQ Mus, Baltic Astronomy 23, 1
Miszalski, B., Mikołajewska, J.: Identification of ne Galactic symbiotic stars with SALT – I. Initial discoveries and other emission line objects, MNRAS 440, 1410
Miszalski, B., Mikołajewska, J., Udalski, A.: OGLE-SMC-LPV-00861 (LIN 9): the first proven Z And outburst in a Magellanic symbiotic star, MNRAS 444, L11
Modzelewska, J., Czerny, B.; Hryniewicz, K. et al: SALT long-slit spectroscopy of CTS C30.10: two-component Mg II line, A&A 570, A53
Oszkiewicz, D.A., Kwiatkowski, T., Tomov, T. et al.: Selecting asteroids for a targeted spectroscopic survey, A&A, 572, A29
Short summary of main results
Dark energy tests with quasar monitoring
Quasars can be used to measure the expansion rate of the Universe. The method is based on the theory of the formation of Broad Emission Lines (Czerny & Hryniewicz 2011). This theory implies the connection between the time delay of the lines with respect to the continuum and the intrinsic absolute monochromatic luminosity in a given source. Observationally, the project requires the measurement of this time delay, which is of order of a few hundred days for quasars at redshift 1.
Monitoring of a small sample with SALT has been started in late 2012. Whereas the monitoring is not yet long enough to measure the time delay some important results has been already obtained, and resulted in 2 refereed papers published in 2014. In particular, Modzelewska et al. (2014; Paper #7) show that the Mg II line (2800 A rest frame) in CTS C30.10, consists of two kinematic components, but only the blue component is accompanied by the Fe II pseudo-continuum (Fig.1). This may be a general property of type B quasars but it could noticed only due to the exceptionally high quality of the SALT data. They also confirm the absence of a separate Narrow Line Region in distant quasars, previously shown in type A quasar LBQS 2113-4538 (Hryniewicz et al. 2014, Paper #1) also observed with SALT. More results and papers are coming in 2015-2016.
Fig.1. Decomposition of the SALT RSS spectrum of quasar CTS C30.10 (z =0.900) into two-component MgII line (pink dotted line), Fe II pseudo-continuum (blue dotted line) and underlying continuum (dashed green line) (Modzelewska et al. 2014, Paper #7).
Central stars of planetary nebulae
Low resolution spectra from various telescopes, including SALT RSS data, were also used to search for variability of the planetary nebulae suspected to host a binary system (Hajduk et al. 2014, Paper #2), and to trace evolution of the [OIII]/Hβ emission line ratio of planetary nebulae hosting central stars (CS) of different type, very likely reflecting their different evolutionary status. This line ratio provides a good proxy for temperature of the central star. The temperature evolution of CS in Hen 2-260 spanning almost decade allowed to precisely determine the stellar mass, since the pace of the temperature evolution depends critically on the core mass. (Hajduk et al. 2014, Paper #3)
Symbiotic stars and other emission line objects
Symbiotic stars (SySt) are interacting binaries with very long orbital periods (from a few years to dozens and even hundreds of years) composed of an evolved giant transferring mass to a compact companion, usually white dwarf (WD; vast majority) although in some SySt a neutron star was also found. The binary is embedded in an ionized nebula. Such a constitution makes them very important tracers of late phases of stellar evolution, as well as promising ”factory” of Supernovae type Ia progenitors. There are major unresolved puzzles concerning their formation and evolution.
The composition of SySt makes them strong Hα emitters associated with very red objects. Miszalski and Mikolajewska have identified a few hundreds of SySt candidates in our Galaxy and a few dozen in the Magellanic Clouds, and since late 2012 have been using SALT with RSS to get spectroscopic confirmation of their symbiotic nature. So far, over 20 new galactic SySt have been found, and 2 in MCs. In 2014, first results of this continued search were published in two referred papers. In particular, the SALT spectra and basic characteristics of 12 new SySt and 3 possible SySt, as well as many other interesting emission-line objects were published by Miszalski & Mikołajewska (2014, Paper #5). The most remarkable among these is the very rare carbon-rich SySt that displays coronal [FeX] and may host a massive white dwarf (Fig.2). This publication based solely on the SALT RSS spectra (~40 spectra presented presented and discussed), in many cases obtained in mediocre weather conditions, was prepared, submitted and accepted in MNRAS within only 1 year since the observations beginning. Miszalski et al. (2014, Paper #6) also discovered that OGLE-SMC-LPV-00861 (LIN 9) is a SySt, and that its OGLE light curves revealed the first proven Z And-type outburst in a Magellanic symbiotic star.
Fig. 2. SALT spectrum of the new C-rich SySt (from Miszalski & Mikołajewska 2014, Paper #5).
Searching for evidence of planetary differentiation
Meteoric evidence suggests 50-100 differentiated parent bodies, yet we know only one fully differentiated asteroid (Vesta). Low resolution spectra obtained with SALT RSS helped determine the taxonomical (a proxy for mineralogical) type of a sample of asteroids and predict the distribution of basaltic material in the Main Asteroid Belt (Oszkiewicz et al. 2014, Paper #8).
Fig. 3. SALT spectra of asteroid (11699) FL105 with the overlaid reflectance values computed from the SDSS photometry. The tick line represents the taxonomical temple for the V-type and the shaded area is the standard deviation of the template (from Oszkiewicz et al. 2014, Paper #8).