\documentstyle[twoside,epsf]{article}
\input ibvs2.sty
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\begin{document}
\IBVShead{6117}{10 October 2014}

\IBVStitle{CH Cygni: new brightening in 2014}

\IBVSauth{ Rspaev, F.; Kondratyeva, L.; Aimuratov, E.}

\IBVSinsto{Fessenkov Astrophysical Institute, Almaty, Kazakhstan.
e-mail: kondr.lud@gmail.com; lu\_kondr@mail.ru}\\

\SIMBADobj{CH Cyg}

The brightest symbiotic object CH Cygni has undergone several
outbursts. Numerous papers are devoted to the study of this object. A
summary of observational history of CH Cyg was presented in the
paper of Contini et al.\ (2009). The last flash took place in 1998-2000 
(Skopal et al.\ 2004) and was followed by a quiescent phase.
Then in 2006 a drop to a very low optical state was registered.
Later it was interrupted by two short brightenings up to $\sim$
8\mm~in $V$ filter, observed during 2009 July and from 2009
September to the end of the year (Skopal et al.\ 2012). Spectral
observations are discussed in many papers as well (e.g.,
Burmeister et al.\ 2009, and Wallerstein et al.\ 2010).


\IBVSfig{7cm}{6117-f1.eps}{Light curve of CH Cyg from 2010 to 2014.
Photoelectric data and results of CCD photometry from Skopal et
al. (2012) are signed by circles and our values by triangles,
blue color is used for $B$ magnitudes and green for $V$ magnitudes. Dates of
our spectroscopic observations are marked by arrows.}
\IBVSfigKey{6117-f1.eps}{CH Cyg}{light curve}




\IBVSfig{8cm}{6117-f2.eps}{Evolution of the H$\alpha$ profiles from
a quiescent stage in 2010 to the recent active phase. X-axis shows
the heliocentric radial velocity in km/s, Y-axis gives a ratio
($I_{\lambda}-I_{\rm cont})/I_{\rm cont}$}.
\IBVSfigKey{6117-f2.eps}{CH Cyg}{other}



\begin{table*}
\begin{center}
\caption{Photometric  results}
\begin{tabular}{ccccc}
\hline
 Date &  HJD&$B$&$V$&$R$\\
      &2400000+&mag&mag&mag\\
 \hline

27.07.2011&55770.479&10.04$\pm 0.05$&8.47$\pm 0.03$&5.02$\pm 0.01$\\
04.08.2011&55778.521&9.76$\pm 0.05$&8.19$\pm 0.02$&4.64$\pm 0.01$\\
02.09.2011&55807.125&9.67$\pm 0.04$&8.08$\pm 0.03$&4.71$\pm 0.01$\\
16.08.2012&56156.190&9.62$\pm 0.04$&7.82$\pm 0.01$&4.52$\pm 0.01$\\
07.06.2013&56451.400&9.72$\pm 0.04$&7.44$\pm 0.02$&4.51$\pm 0.01$\\
08.06.2013&56452.260&9.69$\pm 0.04$&7.43$\pm 0.01$&4.51$\pm 0.01$\\
02.09.2013&56538.370&9.17$\pm 0.03$&7.59$\pm 0.02$&5.00$\pm 0.02$\\
01.10.2013&56567.085&9.02$\pm 0.02$&7.38$\pm 0.02$&4.21$\pm 0.01$\\
24.05.2014&56802.383&8.64$\pm 0.02$&6.94$\pm 0.02$&4.41$\pm 0.01$\\
25.07.2014&56864.250&8.46$\pm 0.01$&7.17$\pm 0.01$&4.47$\pm 0.01$\\
20.08.2014&56890.208&8.35$\pm 0.01$&7.25$\pm 0.02$&4.27$\pm 0.01$\\
22.08.2014&56892.153&8.69$\pm 0.02$&7.14$\pm 0.02$&4.22$\pm 0.01$\\
27.08.2014&56897.149&8.15$\pm 0.03$&7.11$\pm 0.02$&4.82$\pm 0.01$\\
28.08.2014&56898.177&8.03$\pm 0.01$&7.06$\pm 0.02$&4.86$\pm 0.01$\\
29.08.2014&56899.142&8.02$\pm 0.01$&7.06$\pm 0.01$&4.84$\pm 0.01$\\
30.08.2014&56900.148&7.88$\pm 0.02$&6.92$\pm 0.01$&4.86$\pm 0.01$\\
01.09.2014&56902.129&8.06$\pm 0.03$&7.05$\pm 0.02$&4.22$\pm 0.01$\\
 \hline
\end{tabular}
\end{center}
\end{table*}


Our observations of CH Cyg  in Fessenkov Astrophysical Institute
were made in 2011-2014. Photometric observations were
carried out with two telescopes: 1-meter Carl-Zeiss Jena reflector,
equipped with CCD ST-7 (765$\times$510, 9 $\mu$m) and 70 cm telescope
AZT-8, equipped with CCD ST-8 (1530$\times$1020, 9 $\mu$m) and  samples
of  $BVR_{\rm C}$ filters. All obtained images were dark subtracted and
flat fielded. The stars HD195307, HD196330 and HD191418
were adopted as standards. Our observations of CH Cyg were
infrequent because the object was in stable stage. The
 $BVR_{\rm C}$ magnitudes are compiled in Table 1. The light curve of 
 CH Cyg for 2010-2014 is presented in Fig.\ 1. It can be seen that our earlier data,
obtained in 2010-2012, agree with values of Skopal et al.\ (2012) very well.



\begin{table*}
\begin{center}
\caption{Log of spectral observations}
\begin{tabular}{ccccc}
\hline
 Date &  HJD & $\Delta \lambda$ & Telescope &$R=\lambda /\Delta\lambda$ \\
   ~   & 2400000+ &\AA     &~& \AA\\
 \hline
03.09.2010   &   55443.140   &   4400-5200   &   1-meter   &   10000\\
              &              &   6100-6900   &   1-meter   &   13000\\
27.07.2011   &   55770.208   &   6100-7100   &   AZT-8   &   9000\\
04.08.2011   &   55778.267   &   6100-7100   &   AZT-8   &   9000\\
06.08.2011   &   55780.275   &   4300-5300   &   AZT-8   &   7000\\
02.09.2011   &   55807.108   &   4300-5300   &   AZT-8   &   7000\\
16.08.2012   &   56156.240   &   6100-7100   &   AZT-8   &   9000\\
08.06.2013   &   56452.210   &   4400-5200   &   1-meter   &   10000\\
   &       &   6100-6900   &   1-meter   &   13000\\
02.07.2013   &   56476.317   &   6100-6900   &   1-meter   &   13000\\
24.05.2014   &   56802.346   &   6100-6900   &   1-meter   &   13000\\
25.06.2014   &   56834.288   &   4400-5200   &   1-meter   &   10000\\
   &       &   6100-6900   &   1-meter   &   13000\\
25.07.2014   &   56864.229   &   4400-5200   &   1-meter   &   10000\\
   &       &    6100-6900   &   1-meter   &   13000\\
20.08.2014   &   56890.200   &   4300-5300   &   AZT-8   &   7000\\
   &       &   6100-7100   &   AZT-8   &   9000\\
22.08.2014   &   56892.217   &   4400-5200   &   1-meter   &   10000\\
   &       &   6100-6900   &   1-meter   &   13000\\
30.08.2014   &   56900.150   &   4400-5200   &   1-meter   &   10000\\
   &       &   6100-6900   &   1-meter   &   13000\\
 \hline
\end{tabular}
\end{center}
\end{table*}



In the end of May, 2014 the  brightening of CH Cyg has started.
The maximal values of $B$ and $V$  magnitudes
($B=7\fmm88\pm0\fmm02$, $V=6\fmm92 \pm0\fmm02$) are similar to
those observed during previous active phases, 1992-1995 and
1998-2000 (Skopal et al.\ 1997; Skopal\ 2004). High level of
brightness with some fluctuations has been detected to the present.


  Spectral observations have been carried out with two  spectrographs,
  attached to the mentioned telescopes and equipped with the CCD cameras ST-8.
  The slit width equals to 3--4\arcs.
  Wavelength calibration was done using a
laboratory source of HeI, NeI and ArI emission lines. Spectra of
standard stars obtained just before or after the target were used
for the flux calibration. All spectrograms were corrected for
atmospheric extinction. The list of observations is presented in
Table 2. Spectrograms with a dispersion of 0.5 \AA/pixel (1-meter
telescope) and 0.75 \AA/pixel (AZT-8) were obtained in the
``blue" and ``red" spectral ranges (Table 2). Emission lines of HI,
HeI, [OIII], [NII], FeII, [FeII] were observed in the spectra of
CH Cyg. The results of spectral observations are presented in
Table 3. Absolute fluxes $F_{\rm abs}$ are expressed
 in 10$^{-10}$ erg cm$^{-2}$sec$^{-1}$ for H$\alpha$
 and 10$^{-11}$ erg cm$^{-2}$sec$^{-1}$ for other lines. 
 Errors are $\le$10\% for EWs and about 25\%  for
 $F_{\rm abs}$ because of non-uniform late-type continuum.



 Significant strengthening of all
emissions began in 2012. The maximal flux of H$\alpha$ was
registered on 24 May 2014. New increase in the emission fluxes of
HI, [NII], HeI and [OI] was observed in the end of August.
The emission line [OIII], at 5007 \AA~was the strongest earlier -- on
July, 25, and then its flux decreased (Table 3).




The type of  H$\alpha$ profile can be  recognized  only on spectrograms obtained on the 1-meter telescope
with a dispersion of 0.5 \AA/pixel. Thus, we know that in 2010,
H$\alpha$ had a single-peaked profile. Beginning from June,
2013, double-peaked profiles have been observed with variable
ratio of ``blue" to ``red" intensities (Fig.\ 2).  Three possible
types of profile are presented in Fig.\ 2: $V<R$, $V=R$ and $V>R$.
Heliocentric radial velocities of absorption lines were measured with an
uncertainty of about 0.5 \AA~or  $\pm$~20 km/sec. The obtained values
are presented in Table 4.

All observable characteristics of CH Cyg: increasing
brightness, strengthening of the emission lines, and double-peaked
profiles of Balmer  lines testify  a new active phase of the
object.










\begin{table*}
\begin{center}
\caption{Spectral  results}
\begin{tabular}{cc@{\hskip1mm}cc@{\hskip1mm}cc@{\hskip1mm}cc@{\hskip1mm}cc@{\hskip1mm}cc@{\hskip1mm}c}
\hline
\multicolumn{1}{c}{HJD}&\multicolumn{2}{c}{H$\beta$}&\multicolumn{2}{c}{HeI, 4921}&\multicolumn{2}{c}{
[OIII], 5007}&\multicolumn{2}{c}{H$\alpha$}&\multicolumn{2}{c}{[NII], 6583}&\multicolumn{2}{c}{[OI], 6300}\\
2400000+&$F_{\rm abs}$&EW& $F_{\rm abs}$&EW&
$F_{\rm abs}$&EW&$F_{\rm abs}$&EW&$F_{\rm abs}$&EW&$F_{\rm abs}$&EW\\
&10$^{-11}$&\AA&10$^{-11}$&\AA&10$^{-11}$&\AA&10$^{-10}$&\AA&10$^{-11}$&\AA&10$^{-11}$&\AA\\
 \hline
55443.140&1.06&40&&&0.34&15&0.84&35&0.60&2.8&0.91&7.6\\
55770.208&&&&&&&0.43&7.5&0.69&1.7&&\\
55778.267&&&&&&&0.41&7.9&0.64&1.3&0.91&4.3\\
55780.275&0.45&12.3&&&0.19&7.1&&&&&&\\
55807.108&0.39&9.3&&&0.16&4.1&&&&&&\\
56156.240&&&&&&&2.36&47&1.64&3.3&1.30&3.2\\
56452.210&2.81&16&0.74&2.0&2.00&9.3&3.03&22&0.41&0.3&2.83&6.3\\
56476.317&&&&&&&3.78&43&0.59&0.7&2.23&8.7\\
56802.346&&&&&&&17.6&17&1.82&2.4&2.19&4.3\\
56834.288&5.00&26&1.08&2.4&0.75&4.4&5.34&36&2.70&2.7&2.77&6.8\\
56864.229&7.30&29&2.28&1.4&2.94&3.5&6.15&49&3.85&3.7&2.09&4.3\\
56890.200&7.96&18&4.70&4.1&1.26&2.7&6.27&64&5.00&5.1&2.15&4.2\\
56892.217&9.1&26&3.75&2.9&1.52&2.9&7.19&78&4.35&4.8&2.50&5.8\\
56900.150&5.08&11&1.73&3.5&0.90&2.8&6.80&63&7.30&7.7&4.94&5.2\\
\hline
\end{tabular}
\end{center}
\end{table*}

\begin{table*}
\begin{center}
\caption{Radial velocities of the absorption component in the
H$\alpha$ profiles}
\begin{tabular}{c@{\hskip2mm}c@{\hskip2mm}c@{\hskip2mm}c@{\hskip2mm}c@{\hskip2mm}c@{\hskip2mm}c@{\hskip2mm}c@{\hskip2mm}c}
\hline
Date&08.06.2013&02.07.2013&24.05.2014&25.06.2014&25.07.2014&22.08.2014&30.08.2014\\
\hline
$V_{\rm r}$&$-$63&$-$63&$-$46&$-$53&$-$49&$-$34&$-$36\\
\hline
\end{tabular}
\end{center}
\end{table*}

\references

Burmeister, M., Leedjarv, L., 2009, {\it A\&A}, {\bf504}, 171

Contini, M.,   Angeloni, R.,  and Rafanelli, P., 2009, {\it AN}, {\bf
330}, 816

Skopal, A., 1997, {\it IBVS}, {\bf 4495}

Skopal, A., Pribulla, T., Vanko, M. et al., 2004, {\it CoSka}, {\bf 34}, 45

Skopal, A., Shugarov,  S. et al. 2012, {\it AN}, {\bf 333}, 242

Wallerstein, G., Munari, U., Siviero, A. et al., 2010, {\it PASP},
{\bf 122}, 12

\endreferences



\end{document}
