HISTORY

About Astrophysical Spectroscopy Team of Athens
http://www.spectroscopyteam.edu.gr/index.php/research-field
Astrophysical Spectroscopy team of Athens was founded in 1984 by Prof. E. Danezis and Prof. E. Theodosiou at the National and Kapodistrian University of Athens in order to study the peculiar, very broad and strong absorption lines in the UV spectra of Hot Emission Stars (Oe and Be stars) and Quasars that present some satellite absorption components that should not appear in their spectra, according to the classical physical theory.
For the theoretical and mathematical formulation of GR model (a mathematical and physical model for analyzing astronomical spectra) the contribution of  Prof. Theodosiou E., Dr. Lyratzi E., Dr. Nikolaidis, D, Dr. Antoniou A, Dr. Kosionidis, and Prof. Stathopoulou M. was crucial.
Of particular importance is the work of the PhD student MSC D. Stathopoulos, who introduced the fitting criteria which lead to the uniquely determined number of components needed to simulate the complex profiles of DACs, SACs, BALs and BELs. These fitting criteria guarantee not only the unique number of components but the values of the calculated physical parameters as well.
Extremely important was the contribution of  Prof. Theodosiou E., Dr. Lyratzi E., Dr. Antoniou A., Dr. Nikolaidis, D.,  Dr. Kosionidis A., Prof. Stathopoulou  M.,  MSC Stathopoulos  D., Prof. Laskarides, P. G, Dr. Grammenos, Th.,  Dr. Tzimeas D., MSC Bourma, P, MSC Kyriakopoulou, A., MSC Koutroumanou, M, MSC Christou G., Soulikias, A.,and Drakopoulos, Ch., whose tedious work of applying the model in a large number of Hot Stars and Quasars proved the validity of the model.
Finally, important contributions to the theoretical formulation of the model have been made by Prof. Popović, L. Č and Prof. Dimitrijević, M. S and their research teams of the Astronomical Observatory of Belgrade. The cooperation of both research teams produced a series of publications in the fields of Hot Stars and Quasars.
As for ASTA software, the first approach was made by Prof. George Danezis (UCL) when he was an undergraduate student in Cambridge University. The name of the first software was ‘Spectrum’. The second and more advanced approach was developed by Dr. D. Nikolaidis and it was called DMVL. DMVL is the one we used until recently.
The latest software release, which is called A.S.T.A. (Astrophysical Spectroscopy Team of Athens) is designed and developed byDr D. Tzimeas with the help of PhD student D. Stathopoulos and the theoretical contribution of Dr. E. Lyratzi, Dr A, Antoniou  and prof. E. Danezis.
Since 1984 our scientific team published 131 research papers in international peer reviewed journals and conference proceedings which are presented below.
A summary of the scientific field of our team
The research group of Astrophysical Spectroscopy team of the National and Kapodistrian University of Athens was founded in order to study the peculiar, very broad and strong absorption lines in the UV spectra of How Emission Stars (Oe and Be stars, see Fig. 1) and Quasars (see Fig. 4) that present absorption components which should not appear in their spectra, according to the classical physical theory.
Figure. 1: Comparison of the Mg II resonance lines between the spectrum of a normal B star and the spectra of two active Be stars that present complex and peculiar spectral lines. As we can observe the Be stars present some absorption components that do not appear in the spectrum of the classical B star.
These spectral lines were studied by Dr. E. Danezis during his PhD (1980-1984) and were named Satellite Absorption Components (SACs).  Afterwards, these spectral lines were named Discrete Absorption Components (DACs) by Bates & Halliwell,(1986).
According to E. Danezis PhD Thesis SACs (or DACs) are not unknown absorption spectral lines, but spectral lines of the same ion and the same wavelength as a main spectral line, shifted at different Δλ, as they are created in different density regions (inside the stellar wind) which rotate and move radially with different velocities (Danezis 1983, 1987, Danezis et al. 1991, 2003, Lyratzi & Danezis 2004).
The possibility that Hot Star winds are clumpy and the mechanisms producing clumps has been studied by many researchers, although the prevailing view was that Hot Star winds are smooth and continuous. Many researchers proposed mechanisms that allow the existence of structures which cover all or a significant part of the stellar disk, such as shells, blobs or puffs (Underhill 1975, Henrichs 1984, Underhill & Fahey 1984, Bates & Halliwell 1986, Grady et al. 1987, Lamers et al. 1988, Waldron et al. 1992, 1994, Cranmer & Owocki 1996, Rivinius et al. 1997, Kaper et al. 1996, 1997, 1999, Markova 2000), interaction of fast and slow wind components, Co-rotation Interaction Regions (CIRs), structures due to magnetic fields or spiral streams as a result of the stellar rotation (Cranmer & Owocki 1996, Kaper et al. 1996, 1997, 1999, Mulan 1984a, b, 1986, Prinja & Howarth 1988, Fullerton et al. 1997, Cranmer et al. 2000). According to these ideas, DACs result from independent high density regions in the stellar environment (formed inside the wind), which have different rotational and radial velocities.
Another problem of hot emission stars that present DACs is the presence of very complex profile of the main or the discrete components of the spectral lines that we can’t reproduce theoretically. This means that we can’t fit these line profiles with a known distribution, such as Gaussian, Voigt, or Lorentz. As a result we could not know the physical conditions that exist in the high density regions that construct these spectral lines. In order to explain this complex line profiles Danezis et al. 2003, 2007a, Lyratzi & Danezis 2004, Lyratzi et al. 2007 proposed a new phenomenon.
If the regions that construct the DACs rotate with large velocities and move radially with small velocities, the produced lines have large widths and small shifts. As a result, they are blended among themselves as well as with the main spectral line and thus they are not discrete. In such a case the name Discrete Absorption Components is inappropriate and we use the name: Satellite Absorption Components (SACs) (Danezis 1983, 1987, Lyratzi & Danezis 2004, Danezis et al. 2003, 2006, 2007a).
As we can deduce from the above, the DACs and SACs are two aspects of the same phenomenon.
A similar phenomenon can be observed in the spectra of Wolf Rayet Stars, Cataclysmic Variables and BAL Quasars. For this reason our research team extended its research to the study of the UV spectra of Broad Absorption Line Quasars (BALs and BELs).
Figure 2. Comparison of SACs effect in the spectrum of  the Oe star HD 34656  and the same effect in the spectrum of the Quasar PG 1254+047. Black line denotes the observed spectrum while the thin red line denotes the best fit given by our model. Below each fit the individual components that compose the profiles are presented.
Figure 3. C IV resonance lines in the spectrum of PG 0946+301 (right). From the radial displacements and strength ratios of C IV resonance lines one can conclude that the C IV profile exhibits the DAC effect which is similar to the DAC effect presented in the UV spectrum of the hot emission star HD 45910 (left). The black line denotes the observed spectrum, while the red thin line denotes the best fit which results from the model. Below each fit, the individual components that compose the whole profile is presented.
 
 
Figure 4. Best fits and multicomponent analysis of Si IV and C IV resonance lines in the case of the BALQSO J114548.38+393746.6 (left) and the hot star HD 37128 (right). Black solid lines denote the best fits.  Blue thin lines denote the blue component (1393.755 Å for Si IV and 1548.187 for C IV Å) of each doublet while red dashed lines denote the red component of each doublet (1402.77 Å for Si IV and 1550.772 Å for C IV).
Mathematical Expression of the Model
The idea that the complex broad absorption profiles of Hot Emission Stars, exhibiting DACs /SACs or BALs/BELs, are of multicomponent nature had to be cheeked theoretically.
So, our research group solved the radiative transfer equation in the case of a complex plasma region that consist of individual density enhancements in the line of sight. By solving the radiative transfer equation we can calculate the line function of every single individual component that contributes to the final profile. Furthermore, we calculate the interpolation polynomial who (that) can simulate the whole observed profiles. So the model can provide not only the interpolation polynomial that simulates the whole complex profile, but also the line function of each individual component which contributes to the formation of the profile. The line function of every component is a relationship between the observed flux and observed wavelength and contains all the physical parameters of the region that produces each line.
Such a theoretical reproduction of the complex emission and absorption profiles of Hot Emission Stars (DACs, SACs) and BAL Quasars (BALs, BELs) was not possible until 2003 that our research team proposed GR model.
GR model, results from the solution of the radiative transfer equations in the case of a series of individual density regions in the line of sight (Danezis et al. 2003, 2007, 2009, Lyratzi et al. 2007, 2009, Stathopoulos et al. 2015). The model can calculate the values of a series of physical parameters for each DACs, SACs or BALs, BELs component, such as the radial velocities, the FWHM, the optical depth, the equivalent width etc.
It is important to point out that with this model the observed complex emission or absorption profiles are not treated as a unique line. On the contrary, the great advantage of the model is that these profiles can be analyzed to its components that can be studied independently.
Besides that, GR model ensures the uniqueness of the number of components as well as the uniqueness of the values of the calculated physical parameters through specific and strong criteria that are applied in the case of resonance lines (Stathopoulos et al. 2015).
The mathematical expression of the model is an interpolation polynomial of the form [Danezis et al. (2007), Lyratzi et al. (2007)]: 
where:
i: is the number of absorbing density regions (clouds, clumps, density enhancements) that cover the continuum (fully or partially), in the line of sight,
j: is the number of emitting density regions (clouds, clumps, density enhancements)  in the line of sight,
g: is the number of additional absorbing density regions (clouds, clumps, density enhancements) that may cover the i absorbing clouds as well as the j emitting clouds,
: is the initial radiation intensity
: is the line function of the i absorption component
: is the factor that describes the synthesis of absorption lines produced by i clouds (DAC/BAL),
is the line function of the i emission component
: is the factor that describes the summation of emission lines produced by j clouds (e.g. BELs),
: is the factor that describes absorbing clouds that may obscure both the i absorbing as well as the j emitting clouds,
: are the distribution functions of the absorption coefficients ,
: is the absorption coefficient of the ith cloud in the line of sight,
:is the emitting coefficient of the jth cloud in the line of sight,
:is the absorption coefficient of the additional absorbing clouds that may cover the i and j clouds in the line of sight,
ξ: is the optical depth in the center of the spectral line,
: is the source function that is constant during one observation
The geometry of the model is included in the factors “L” (Lyratzi et al. 2007; Danezis, et al. 2007) of Eq. 1. After investigating a number of geometries we concluded that the best fit of absorption/emission lines is accomplished if the geometry is spherical (Markova 2000; Bates&Gilheany 1990; Gilheanyet al. 1990; Waldron et al. 1992; Riviniuset al. 1997; Danezis 1983). Apart from the geometry, the parameters “L” can take the expression of one of the following distributions, according to the physical conditions we like to describe. So “L” can take the form of either Gauss (random motions – thermal and non thermal), or Lorentz (pressure), or Voigt (random motions and pressure), or Rotation (rotation of a region around its own center, Danezis et al. 2003;Danezis et al. 2007) or Gauss – Rotation (random motions and rotation of a region around its own center, Danezis et al. 2003;Danezis et al. 2007).
Publications (The Smithsonian/NASA Astrophysics Data System)
Publications in International Referred Journals
Stathopoulos,D.; Danezis, E.; Lyratzi, E.; Antoniou, A.; Tzimeas, D., Multicomponent Analysis of the UV Si IV and C IV Broad Absorption Troughs in BALQSO Spectra: The Examples of J01225 + 1339 and J02287 + 0002, 2015, JApA, 36, 495
Antoniou, A., Danezis, E., Lyratzi, E., Stathopoulos, D.: A statistical study of C IV regions in 20 Oe-type stars,2014A, AdSpR, Special Issue: “Line Shapes in Astrophysics”
Antoniou, A., Danezis, E., Lyratzi, E., Stathopoulos, D.: The structure of the Si IV region in Be stars: a study of Si IV spectral lines in Be 68 stars, 2012, JPhCS, 399, 2021
Lyratzi, E., Danezis, E., Popović, L. Č., Antoniou, A., Dimitrijević, M. S., Stathopoulos, D.: The Complex Broad Absorption Line Profiles in a Sample of QSO Spectra,2011, BaltA, 20, 448
Antoniou, A., Stathopoulos, D., Danezis, E., Lyratzi, E.: Studying the UV Mg II Resonance Lines in 20 Be Stars,2011, BaltA, 20, 572
Antoniou, A., Danezis, E., Lyratzi, E., Stathopoulos, D., Dimitrijević, M. S.: A Statistical Study of the Si IV Resonance Line Parameters in 19 Be Stars, 2011, BaltA, 20, 548
Lyratzi, E., Danezis, E., Popović, L. Č., Antoniou, A., Dimitrijević, M. S., Stathopoulos, D.: Studying the complex BAL profiles in the BALQSQs spectra, 2010, JPhCS, 257, 2035
Lyratzi, E., Danezis, E., Popović, L. Č., Antoniou, A., Dimitrijević, M. S., Stathopoulos, D.: Using The GR Model To Study The AGN Spectra, 2010, POBeo, 89, 348
Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A.:Interpreting the complex line profiles in the stellar spectra,2009, NewAR, 53, 214
Lyratzi, E., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A.:Kinematics of the broad absorption line regions in QSQs: Rotation and Random motions, 2009, NewAR, 53, 179
Antoniou, A., Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Theodossiou, E., Stathopoulos, D.: A study of the atmospheric structure of AXMon (HD 45910), 2009, CoAst, 159, 119
Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: Kinematical parameters in the coronal and post-coronal regions of the Oe stars, 2008, POBeo, 84, 443, 2008, JPhCS, 133a, 2028, 24th Summer School and International Symposium on the Physics of Ionized Gases, (SPIG 2008), August 25-29, 2008, Novi Sad, Serbia
Lyratzi, E., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A.: DACs and SACs phenomena in the C IV emitting regions of QSOs,2008, POBeo, 84, 483, 24th Summer School and International Symposium on the Physics of Ionized Gases, (SPIG 2008), August 25-29, 2008, Novi Sad, Serbia
Danezis, E., Lyratzi, E., Popović, L. Č., Antoniou, A., Dimitrijević, M. S.:The very broad lines in the UV spectra of hot emission stars – A possible explanation, 2008, POBeo, 84, 463, 24th Summer School and International Symposium on the Physics of Ionized Gases, (SPIG 2008), August 25-29, 2008, Novi Sad, Serbia
Antoniou, A., Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Theodossiou, E., Stathopoulos, D.: A study of AX Mon (HD 45910) kinematical parameters of the Fe II density regions, 2008, POBeo, 84, 455, 24th Summer School and International Symposium on the Physics of Ionized Gases, (SPIG 2008), August 25-29, 2008, Novi Sad, Serbia
Danezis, E., Nikolaidis D., Lyratzi, E., Popović, L. Č., Dimitriević, M. S., Antoniou, A., Theodosiou, E.: A new model for the structure of DACs and SACs regions in Oe and Be stellar atmospheres, 2007, PASJ, 59, 827
Lyratzi, E., Danezis, E., Popović, L. Č., Dimitijević, M. S. & Nikolaidis D.:The complex structure of the MgII λλ523, 2802.698 A regions of 64 Be stars, 2007, PASJ, 59, 357
Danezis, E., Lyratzi, E., Nikolaidis D., Stathopoulou, M., Theodosiou, E., Drakopoulos, C., Soulikias, A. Antoniou, A.: On modelling SAC’s regions in early type atmospheres,2003, POBeo, 76, 179
Danezis, E., Antoniou, A., Lyratzi, E., Theodosiou, E., Stathopoulou, M., Nikolaidis D., Drakopoulos, C., Soulikias, A., Koutroumanou, M.: The complex coronal structure of the Oe star HD 175754,2003, POBeo, 76, 175
Lyratzi, E., Danezis, E., Stathopoulou, M., Theodosiou, E., Nikolaidis D., Drakopoulos, C., Soulikias, A.: The complex structure of the Mg II regions of 40 BeV stars, 2003, POBeo, 76, 27
Danezis, E., Nikolaidis, D., Lyratzi, Ε., Stathopoulou, M., Theodossiou, E., Kosionidis, A., Drakopoulos, C., Christou, G., Koutsouris P.: ΑNew Model for the Structure of the DACs Regions in the Oe and Be stars, 2003, Ap&SS, 284, 1119
Danezis, E., Antonopoulou, E., Theodossiou, E.: The UV spectrum of the Binary system TY Pyx, 1993, Ap&SS, 200, 47
Danezis, E., Antonopoulou, E., Theodossiou, E. & Mathioudakis, M.:The UV spectrum of the binary system SZ Psc, 1992, Ap&SS, 187, 307
Theodossiou, E., Danezis, E.: The stellar temperature scale for stars of spectral types O8-F6 and the standard deviation of the MK spectral classification,1991, Ap&SS, 183, 91
Laskarides, P. G., Danezis, E., Theodossiou E.:The far UV spectrum of the O4I(n)f star ζ Puppis, 1991, Ap&SS, 183, 67
Danezis, E., Theodossiou, E., Laskarides, P. G.: The far UV spectrum of the Be star AX Monocerotis, 1991, Ap&SS, 179, 111
Laskarides, P. G., Theodossiou, E., Danezis, E.: The far UV spectrum of the O4V(f) star 9 Sagittarii,1991, Ap&SS, 179, 13
Danezis, E., Theodossiou, E.: The UV spectrum of the Be star 88 Herculis,1990, Ap&SS, 174, 49
Danezis, E., Theodossiou, E.: The far UV spectrum of the Be star 88 Herculis,1988, A&AS, 72, 497
Kontizas, M., Danezis, E., Kontizas, E.: Observed radii and structural parameters of clusters in SMC, 1982, A&AS, 49, 1
Δανέζης, E.: Συμβολή στη μελέτη των Be αστέρων – Το διπλό σύστημα του AX Mon, Διδακτορική διατριβή, Αθήνα 1984
Publication in Conference Proceedings
  1. Stathopoulos, E. Lyratzi, E. Danezis, A. Antoniou, D. Tzimeas, 2012, A Study of the C IV BALs in HiBALQSO Spectra, 26th Summer School and International Symposium on the Physics of Ionized Gases.
  2. Antoniou, E. Danezis, E. Lyratzi, L. Č. Popović, M. S. Dimitrijević and D. Stathopoulos, 2012, THE STRUCTURE OF Si IV REGION IN Be STARS; A STUDY OF Si IV SPECTRAL LINES IN 68 Be STARS, 26th Summer School and International Symposium on the Physics of Ionized Gases.
  3. Danezis, D. Stathopoulos, E. Lyratzi, L. Č. Popović, A. Antoniou, M. S. Dimitrijević, D. Tzimeas, 2013, Some new ideas to study the complex BAL profiles in the spectra of AGNs, 9th Serbian Conference on Spectral Line Shapes in Astrophysics Banja Koviljaca, Serbia, May 13-17, 2013.
  4. Antoniou, E. Danezis, E. Lyratzi and D. Stathopoulos, 2013, A statistical study of C IV regions in 20 Oe-type stars, 9th Serbian Conference on Spectral Line Shapes in Astrophysics Banja Koviljaca, Serbia, May 13-17, 2013
  5. Lyratzi, E. Danezis, D. Stathopoulos, L. Č. Popović, A. Antoniou, M. S. Dimitrijević, D. Tzimeas, 2013, Studying the complex BAL profiles of SIV in 30 BALQSOs spectra, 9th Serbian Conference on Spectral Line Shapes in Astrophysics Banja Koviljaca, Serbia, May 13-17, 2013.
  6. Stathopoulos, E. Danezis, E. Lyratzi, L. Č. Popović, A. Antoniou, M. S. Dimitrijević, D. Tzimeas, 2013, Studying the complex BAL profiles of C IV in 30 BALQSO spectra, 9th Serbian Conference on Spectral Line Shapes in Astrophysics Banja Koviljaca, Serbia, May 13-17, 2013.
  7. Stathopoulos, E. Danezis, E. Lyratzi, A. Antoniou, LC. Popović, D. Tzimeas, M. S. Dimitrijević, Studying the complex absorption profiles of Si IV in 21 HiBALQSO spectra, 2014, JPhCS, 565a2020S.
  8. Lyratzi, E., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A.:Ways of creation of DACs and SACs in the spectra of PG 0946+301 and PG 1254+047, 2010, ASPC, 424, 308
  9. Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A.: Investigating DACs/SACs Phenomena in Hot Emission Stars and Quasars, 2010, ASPC, 424, 305
  10. Antoniou, A., Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Stathopoulos, D.: A New Approach of the GR Model, 2010, ASPC, 424, 187
  11. Lyratzi, E., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A., Stathopoulos, D.: Kinematic properties of the Broad Absorption Line Regions in the spectra of quasars, 2010, MSAIS, 15, 161
  12. Antoniou, A., Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Theodossiou, E.: Studying the location of SACs and DACs regions in the environment of hot emission stars, 2010, MSAIS, 15, 138
  13. Danezis, E., Lyratzi, E., Antoniou, A., Popović, L. Č., Dimitrijević, M. S.:Studying the complex spectral line profiles in the spectra of hot emission stars and quasars, 2010, MSAIS, 15, 13
  14. Danezis, E., Lyratzi, E.: 1st workshop: Astrophysical winds and disks – Similar phenomena in stars and quasars, 2010, MSAIS, 15, 6
  15. Lyratzi, E., Danezis, E., Nikolaidis D., Popović, L. Č., Dimitijević, M. S., Theodosiou, E., Antoniou, A.:A new approach for the structure of Halpha  regions in 120 Be-type stars2005, MSAIS, 7, 114
  16. Danezis, E., Nikolaidis D., Lyratzi, E., Popović, L. Č., Dimitijević, M. S., Theodosiou, E., Antoniou, A.: A new modeling approach for DACs and SACs regions in the atmospheres of hot emission stars2005, MSAIS, 7, 107
  17. Lyratzi, E., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A.:DACs and SACs in the UV Spectrum of the Quasar PG 0946+3012008, AIPC, 1058, 323, 19th International Conference on Spectral Line Shapes, (19 ICSLS), June 15 – 20, 2008, Valladolid, Spain
  18. Lyratzi, E., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A.:Kinematics of Broad Absorption Line Regions of PG 1254+0472008, AIPC, 1058, 320, 19th International Conference on Spectral Line Shapes, (19 ICSLS), June 15 – 20, 2008, Valladolid, Spain
  19. Antoniou, A., Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Theodosiou, E., Katsavrias, G.: A Study of the Structure of Different Ionization Potential Regions in the Atmosphere of AX Mon (HD 45910),2008, AIPC, 1058, 317, 19th International Conference on Spectral Line Shapes, (19 ICSLS), June 15 – 20, 2008, Valladolid, Spain
  20. Antoniou, A., Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Theodosiou, E., Stathopoulos, D.: AX Mon (HD 45910) Kinematical Parameters in the Fe II Spectral Lines as a Function of the Excitation Potential2008, AIPC, 1058, 314, 19th International Conference on Spectral Line Shapes, (19 ICSLS), June 15 – 20, 2008, Valladolid, Spain
  21. Danezis, E., Lyratzi, E., Popović, L. Č. & Dimitrijević, M. S., Antoniou, A.:Similarity Between DACs/SACs Phenomena in Hot Emission Stars and Quasars Absorption Lines, 2008, AIPC, 1058, 305, 19th International Conference on Spectral Line Shapes, (19 ICSLS), June 15 – 20, 2008, Valladolid, Spain
  22. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: Investigation of the post coronal density regions of Oe stars, through the N V UV resonance lines2007, AIPC, 938, 210, VI Serbian Conference on Spectral Line Shapes in Astrophysics (VI SCSLSA), June 2007, Sremski Karlovci, Serbia
  23. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: The N IV density regions in the spectra of 20 Oe stars,2007, AIPC, 938, 206, VI Serbian Conference on Spectral Line Shapes in Astrophysics (VI SCSLSA), June 2007, Sremski Karlovci, Serbia
  24. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, Popović, L. Č., Dimitrijević, M. S.: Long term variability of the coronal and post-coronal regions of the Oe star HD 149757 (zeta Oph)2007, AIPC, 938, 198, VI Serbian Conference on Spectral Line Shapes in Astrophysics (VI SCSLSA), June 2007, Sremski Karlovci, Serbia
  25. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: A statistical study of physical parameters of the C IV density regions in 20 Oe stars2007, AIPC, 938, 194, VI Serbian Conference on Spectral Line Shapes in Astrophysics (VI SCSLSA), June 2007, Sremski Karlovci, Serbia
  26. Lyratzi, E., Danezis, E., Dimitrijević, M. S., Popović, L. Č., Nikolaidis, D., Antoniou, A.: The Evolution of Some Physical Parameters in the DACs/SACs Regions in Be Stellar Atmospheres2007, AIPC, 938, 176, VI Serbian Conference on Spectral Line Shapes in Astrophysics (VI SCSLSA), June 2007, Sremski Karlovci, Serbia
  27. Danezis, E., Antoniou, A., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Nikolaidis, D.: The DACs and SACs Effects From Stars to Quasars. Some First General Notices2007, AIPC, 938, 119, VI Serbian Conference on Spectral Line Shapes in Astrophysics (VI SCSLSA), June 2007, Sremski Karlovci, Serbia. (Προσκεκλημένη ομιλία)
  28. Chatzichristou, E. T., Danezis, E., Popović, L. Č., Lyratzi, E., Dimitrijević, M. S.: Studying the complex absorption and emission lines in AGN spectra, 2007, AIPC, 938, 65, VI Serbian Conference on Spectral Line Shapes in Astrophysics (VI SCSLSA), June 2007, Sremski Karlovci, Serbia
  29. Lyratzi, E., Danezis, E., Antoniou, A., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: The complex structure of the Si IV 1393.755, 1402.77 A regions of 68 Be-type stars, 2007, uasb.conf, 137
  30. Danezis, E., Antoniou A., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S., Theodossiou, E.: Long term variability of the coronal and post – coronal C IV region of the Oe star HD 93521, 2007, uasb.conf, 113
  31. Danezis, E., Popović, L. Č., Lyratzi, E., Dimitrijević, M. S.: The peculiar absorption and emission phenomena from stars to quasars,2006, AIPC, 876, 373, 23rd Summer School and International Symposium on the Physics of Ionized Gases, (SPIG 2006), 2006, August 28 – September 1, Kopaonik, Serbia (Προσκεκλημένηομιλία)
  32. Nikolaidis, D., Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Antoniou. A., Theodossiou, E.: A New Approach For DACs And SACs Phenomena In The Atmospheres Of Hot Emission Stars,2006, IAUJD, 4E, 112007, uasb.conf, 107, XXVIth IAU General Assembly, 2006, August 14-25, Prague, Czech Republic
  33. Lyratzi, E., Danezis, E., Antoniou, A., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: The complex structure of the Si IV λλ755, 1402.77 A regions of 68 Be-type stars2006, IAUJD, 4E, 10,2007, uasb.conf, 137, XXVIth IAU General Assembly, 2006, August 14-25, Prague, Czech Republic
  34. Lyratzi, E., Danezis, E., Antoniou, A., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: Study of Hα regions in 120 Be-type stars,2006, IAUJD, 4E, 92007, uasb.conf, 131, XXVIth IAU General Assembly, 2006, August 14-25, Prague, Czech Republic
  35. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: Hyper Ionization Phenomena In The N V Region Of 20 Oe Stars, 2006, IAUJD, 4E, 72007, uasb.conf, 155, XXVIth IAU General Assembly, 2006, August 14-25, Prague, Czech Republic
  36. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: Hyper Ionization Phenomena In The N IV Region Of 20 Oe Stars, 2006, IAUJD, 4E, 62007, uasb.conf, 149, XXVIth IAU General Assembly, 2006, August 14-25, Prague, Czech Republic
  37. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: Hyper Ionization Phenomena In The C IV Region Of 20 Oe Stars, 2006, IAUJD, 4E, 52007, uasb.conf, 143, XXVIth IAU General Assembly, 2006, August 14-25, Prague, Czech Republic
  38. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S.: Long Term Variability Of The Coronal and Post – Coronal Regions Of The Oe Star HD 93521, 2006, IAUJD, 4E, 4, XXVIth IAU General Assembly, 2006, August 14-25, Prague, Czech Republic
  39. Lyratzi, E., Danezis, E., Nikolaidis, D., Antoniou, A., Popović, L. Č., Dimitrijević, M. S., Stathopoulou, M., Theodossiou, E.: A New Approach For The Structure Of Ha Regions In 120 Be-type Stars, 2006, AIPC, 848, 402, RECENT ADVANCES IN ASTRONOMY AND ASTROPHYSICS: 7th International Conference of the Hellenic Astronomical Society, September 2005, Kefallinia Island, Greece
  40. Danezis, E., Nikolaidis, D., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Theodossiou, E., Antoniou, A.: A New Modeling Approach For DACs And SACs Regions In The Atmospheres Of Hot Emissions Stars, 2006, AIPC, 848, 380, RECENT ADVANCES IN ASTRONOMY AND ASTROPHYSICS: 7th International Conference of the Hellenic Astronomical Society, September 2005, Kefallinia Island, Greece
  41. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S., Theodossiou, E.: Long Term Variability of the Radial Velocities in the Coronal and Post-coronal Regions of the Oe Star HD 93521, 2006, AIPC, 848, 370, RECENT ADVANCES IN ASTRONOMY AND ASTROPHYSICS: 7th International Conference of the Hellenic Astronomical Society, September 2005, Kefallinia Island, Greece
  42. Popović, L. Č., Dimitrijević, M. S., Mediavilla, E., Danezis, E., Lyratzi, E., Bon, E., Ilic, D., Jovanovic, P., Theodossiou, E. & Dacic, M.: Some spectroscopic methods for astrophysical plasma research,2004, AIPC, 740, 497, 22nd Summer School and International Symposium on the Physics of Ionized Gases (SPIG 2004), 2004, August, 23 – 27, National Park “TARA”, Serbia and Montenegro. (Προσκεκλημένη ομιλία)
  43. Lyratzi, Ε., Danezis, E.: SACs and DACs phenomena in the atmospheres of hot emission stars, 2004, AIPC, 740, 458, 22nd Summer School and International Symposium on the Physics of Ionized Gases (SPIG 2004), 2004, August, 23 – 27, National Park “TARA”, Serbia and Montenegro. (Προσκεκλημένη ομιλία)
  44. Danezis, E., Koutroumanou, M., Lyratzi, Ε., Theodossiou, E., Stathopoulou, M., Nikolaidis, D., Antoniou, A., Drakopoulos, C., Soulikias, A.: Discontinuous structure of SiIV regions in the Oe star’s λ Orionis atmosphere, 2004, hell.conf, 117, 6th Astronomical Conference of the Hellenic Astronomical Society, September 2005, Athens, Greece
  45. Lyratzi, Ε., Danezis, E., Stathopoulou, M., Theodossiou, E., Nikolaidis, D., Antoniou, A., Drakopoulos, C., Soulikias, A., Koutroumanou, M.:Discontinuous phenomena in SiIV regions of BeV stars,2004, hell.conf, 116L, 6th Astronomical Conference of the Hellenic Astronomical Society, September 2005, Athens, Greece
  46. Danezis, E., Antoniou, A., Lyratzi, Ε., Theodossiou, E., Stathopoulou, M., Nikolaidis, D., Drakopoulos, C., Soulikias, A., Koutroumanou, M.:Discontinuous structure and SACs phenomena in the Oe star’s HD 175754 atmosphere, 2004, hell.conf, 116D, 6th Astronomical Conference of the Hellenic Astronomical Society, September 2005, Athens, Greece
  47. Lyratzi, Ε., Danezis, E., Stathopoulou, M., Theodossiou, E., Nikolaidis, D., Antoniou, A., Drakopoulos, C., Soulikias, A., Koutroumanou, M.:Discontinuous phenomena in MgII regions of BeV stars,2004, hell.conf, 115L, 6th Astronomical Conference of the Hellenic Astronomical Society, September 2005, Athens, Greece
  48. Danezis, E., Lyratzi, Ε., Nikolaidis, D., Theodossiou, E., Stathopoulou, M., Drakopoulos, C., Soulikias, A.: Discontinuous structures in early type stars’ atmospheres, 2004, hell.conf, 115D, 6th Astronomical Conference of the Hellenic Astronomical Society, September 2005, Athens, Greece
  49. Danezis, E., Lyratzi, E., Nikolaides, D., Theodossiou, E., Stathopoulou, M., Christou, G., Drakopoulos, C., Kosionidies, A., Soulikias, A.:Applications of a New Model of Density Layers of Matter in the Expanding Gaseous Envelope of Oe and Be Stars, 2003, IAUS, 210P, E29, 210th Symposium of the International Astronomical Union, June 2002, Uppsala, Sweden
  50. Danezis, E., Nikolaides, D., Lyratzi, E., Stathopoulou, M., Theodossiou, E., Kosionidies, A., Drakopoulos, C., Christou, G., Koutsouris, P.: A new model of density layers of matter to the expanding gaseous envelope of Oe and Be stars, 2003, IAUS, 210P, E3, 210th Symposium of the International Astronomical Union, June 2002, Uppsala, Sweden
  51. Lyratzi, E., Danezis, E., Nikolaidis, D., Theodossiou, E., Stathopoulou, M., Drakopoulos, Ch., Bourma, P.: Application of a new model of density shells of matter to the expanding gaseous envelope of the star HD 45910 (AXMonocerotis), 2001, hell.confE, 67, 5th Hellenic Astronomical Conference, September 2001, Crete, Greece
  52. Danezis, E., Nikolaides, D., Lyratzi, E., Stathopoulou, M., Theodossiou, E., Kyriakopoulou, A., Christou, G., Kossionides, A., Drakopoulos, C.: The complex structure of the expanding gaseous envelope of the star HD 164794 (9Sagittarii), 2001, hell.confE, 66, 5th Hellenic Astronomical Conference, September 2001, Crete, Greece
  53. Danezis, E., Lyratzi, E., Theodossiou, E., Nikolaidis, D., Stathopoulou, M., Kiriakopoulou, A., Ghristou, G., Drakopoulos, Ch.: Application of a new model of density shells of matter to the expanding gaseous envelope of the star HD 175754, 2001, hell.confE, 65, 5th Hellenic Astronomical Conference, September 2001, Crete, Greece
  54. Danezis, E., Nikolaidis, D., Lyratzi, E., Stathopoulou, M., Theodossiou, E., Kosionidis, Α., Drakopoulos, Ch., Soulikias, A.: Phenomena of hyperionization and emission in the gaseous envelope of the star λ Orionis,2001, hell.confE, 64, 5th Hellenic Astronomical Conference, September 2001, Crete, Greece
  55. Danezis, E., Christou, G., Stathopoulou, M., Theodossiou, E., Nikolaidis, D., Lyratzi, E., Drakopoulos, Ch., Bourma, E., Soulikias, A.: Phenomena of hyperionization and emission in the gaseous envelope of the star HD 66811 (ζ Puppis), 2001, hell.confE, 63, 5th Hellenic Astronomical Conference, September 2001, Crete, Greece
  56. Danezis E., Kiriakopoulou A., Nikolaidis D., Theodossiou E., Stathopoulou M., Lyratzi E., Ghristou G., Kosionidis A.: A final consideration of the developing velocity fields in the gaseous envelope of the star HD 50138,2001, hell.confE, 62, 5th Hellenic Astronomical Conference, September 2001, Crete, Greece
  57. Theodossiou, E., Laskarides, P.G., Stathopoulou, E., Danezis, E., Grammenos, Th.: A study of the superionized spectral lines of the star HD 36861, 1997, jena.confE, 165, Joint European and National Astronomical Meeting, JENAM-97, 6th European and 3rd Hellenic Astronomical Conference, July 2-5, 1997, Thessaloniki, Greece
  58. Stathopoulou, Μ., Danezis, E., Theodossiou, E., Grammenos, Th., Soulikias, A.: A study of the superionized spectral lines of the star HD 152408, 1997, jena.confE, 164, Joint European and National Astronomical Meeting, JENAM-97, 6th European and 3rd Hellenic Astronomical Conference, July 2-5, 1997, Thessaloniki, Greece
  59. Stathopoulou, M., Danezis, E., Theodossiou, E., Grammenos, Th., Soulikias, A.: A study of the superionized spectral lines of the star HD 164794, 1997, jena.confE, 121, Joint European and National Astronomical Meeting, JENAM-97, 6th European and 3rd Hellenic Astronomical Conference, July 2-5, 1997, Thessaloniki, Greece
  60. Danezis, E., Stathopoulou, M., Theodossiou, E., Grammenos, Th., Kosionidis, A.: A study of the superionized spectral lines of the star HD 66811, 1997, jena.confE, 120, Joint European and National Astronomical Meeting, JENAM-97, 6th European and 3rd Hellenic Astronomical Conference, July 2-5, 1997, Thessaloniki, Greece
  61. Stathopoulou, M., Danezis, E., Laskarides, P. G., Theodossiou, E.: The UV Spectrum of HD 175754, 1996, hell.conf, 212, Proceedings of the 2nd Hellenic Astronomical Conference, June 29-July 1, 1995 Thessaloniki, Greece
  62. Danezis, E., Theodossiou, E., Laskarides, P. G.: A first approach to the shell structure of Be binary stars, 1996, hell.conf, 195, Proceedings of the 2nd Hellenic Astronomical Conference, June 29-July 1, 1995 Thessaloniki, Greece
  63. Danezis, E. Antonopoulou, E., Mathioudakis, M., Theodossiou, E.: The UV spectrum of the RS VCn binary SZ PSc, 1992, LNP, 397, 273, Surface Inhomogeneities on Late-Type Stars, Proceedings of a Colloqium Held at Armagh Observatory, Northern Ireland 24-27 July 1990
  64. Danezis, E.: The Far UV Spectrum of Binary System Ax Mon, (Physics of Be stars, Cambridge University Press), 1987, pbes.coll, 445, Proceedings of IAU Colloq. 92, August 1986, University of Colorado, Boulde
Other Publications (not appearing in the
  1. Δανέζης, Ε.: 14ο Πανελληνίο Συνεδρίο Φυσικής στα Καμένα Βούρλα, 19 Μαρτίου – 1 Απριλίου 2012, προσκεκλημένη ομιλία με θέμα: «Μελετώντας τα φάσματα αστέρων και quasars»
  2. Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A.:DACs/SACs phenomena in astrophysical spectra, Joint European and National Astronomical Meeting (JENAM 2008), September 8-12, 2008, Vienna, Austria
  3. Lyratzi, E., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Antoniou, A.:An analysis of C IV and Si IV lines in the spectra of the quasars PG 0946+301 and PG 1254+047, Joint European and National Astronomical Meeting (JENAM 2008), September 8-12, 2008, Vienna, Austria
  4. Antoniou, A., Danezis, E., Lyratzi, E., Popović, L. Č., Dimitrijević, M. S., Katsavrias, G.: The structure of atmospherical layers of AX Mon (HD 45910), Joint European and National Astronomical Meeting (JENAM 2008), September 8-12, 2008, Vienna, Austria
  5. Danezis, E., Lyratzi, E., Nikolaidis, D., Antoniou, A., Popović, L. Č., Dimitrijević, M. S.:The SACs Broadening, 23rd Summer School and International Symposium on the Physics of Ionized Gases (SPIG 2006), August 28 – September 1, 2006, Kopaonik, Serbia
  6. Lyratzi, E., Danezis, E., Nikolaidis, D., Antoniou, A., Popović, L. Č., Dimitrijević, M. S., Theodossiou, E.: The Photospheric And The Respective Si IV Regions’ Rotational Velocities In 27 Be Stars, 23rd Summer School and International Symposium on the Physics of Ionized Gases, (SPIG 2006), August 28 – September 1, 2006, Kopaonik, Serbia
  7. Nikolaidis, D., Danezis, E., Lyratzi, E., Popović, L. Č., Antoniou, A. Dimitrijević, M. S., Theodossiou, E.: A Study Of DACs And SACs Regions In The Atmospheres Of Hot Emissions Stars, 23rd Summer School and International Symposium on the Physics of Ionized Gases, (SPIG 2006), August 28 – September 1, 2006, Kopaonik, Serbia
  8. Antoniou, A., Danezis, E., Lyratzi, E., Nikolaidis, D., Popović, L. Č., Dimitrijević, M. S., Theodossiou, E.: The Photospheric And The Respective C IV Regions’ Rotational Velocities In 20 Oe Stars, 23rd Summer School and International Symposium on the Physics of Ionized Gases, (SPIG 2006), August 28 – September 1, 2006, Kopaonik, Serbia
  9. Lyratzi, Ε., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Nikolaidis, D., Soulikias, A., Antoniou, A., Stathopoulou, M.: The complex structure of the SiIV λλ73, 1402.73 A regions of 57 BeV stars, JENAM 2004, September, 13-17, 2004, Granada, Spain
  10. Danezis, E., Antoniou, A., Popović, L. Č., Dimitrijević, M. S., Lyratzi, Ε., Nikolaidis, D., Soulikias, A., Theodossiou, E.: Satellite Absorption Components of the UV spectral lines SiIV, CIV, NV, and NIV in the atmosphere of the Oe star HD 175754, JENAM 2004, September, 13-17, 2004, Granada, Spain
  11. Danezis, E., Lyratzi, Ε., Popović, L. Č., Dimitrijević, M. S., Christou, G., Soulikias, A., Antoniou, A.: Satellite Absorption Components of the UV spectral lines SiIV, CIV, NV, and NIV in the atmosphere of the Oe star HD 66811 (ζPup), JENAM 2004, September, 13-17, 2004, Granada, Spain
  12. Lyratzi, Ε., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Nikolaidis, D., Thiedossiou, E., Soulikias, A., Antoniou, A.: The complex structure of the MgII λλ523, 2802.698 A regions of 64 Be stars, 17thInternational Conference on Spectral Line Shapes (17th ICSLS), June 21-25, 2004, Paris, France
  13. Lyratzi, Ε., Danezis, E., Popović, L. Č., Dimitrijević, M. S., Nikolaidis, D., Theiodossiou, E., Soulikias, A., Antoniou, A.: The complex structure of the SiIV λλ73, 1402.73 A regions of 42 BeV stars,17th International Conference on Spectral Line Shapes (17th ICSLS), June 21-25, 2004, Paris, France
  14. Popović, L. Č., Danezis, E., Lyratzi,E., Dimitrijević, M. S., Theodossiou E.: A model for the Broad Absorption Line Region in BAL-QSOs,The conference of Euro-asian astronomical society, Russian Astronomical conference, July, 2 – 10, 2004, Moscow, Russia
  15. Danezis, E., Lyratzi, Ε., Nikolaidis, D., Theodossiou, E., Stathopoulou, M., Drakopoulos, C., Soulikias, A.: SACs phenomena in early type stars,JENAM 2003, August 25 – 31, 2003 Budapest, Hungary.
  16. Lyratzi, Ε., Danezis, E., Stathopoulou, M., Theodossiou, E., Nikolaidis, D., Antoniou, A., Drakopoulos, C., Soulikias, A, Koutroumanou, M.: SACs phenomena in MgII regions of 40 BeV stars, JENAM 2003, August 25 – 31, 2003 Budapest, Hungary
  17. Lyratzi, Ε., Danezis, E., Stathopoulou, M., Theodossiou, E., Nikolaidis, D.,Antoniou, A., Drakopoulos, C., Soulikias, A., Koutroumanou, M.: SACs phenomena in SiIV regions of 42 BeV stars, JENAM 2003, August 25 – 31, 2003 Budapest, Hungary
  18. Danezis, E., Antoniou, A., Lyratzi, Ε., Theodossiou, E., Stathopoulou, M., Nikolaidis, D., Drakopoulos, C., Soulikias, A., Koutroumanou, M.: The complex structure of hyperionization regions of the Oe star HD 175754, JENAM 2003, August 25 – 31, 2003 Budapest, Hungary
  19. Danezis, E., Koutroumanou, M., Lyratzi, Ε., Theodossiou, E., Stathopoulou, M., Nikolaidis, D., Antoniou, A., Drakopoulos, C., Soulikias, A.: The complex structure of SiIV regions of the Oe star λOrionis, JENAM 2003, August 25 – 31, 2003 Budapest, Hungary
  20. Lyratzi E., Danezis E., Nikolaidis D., Theodossiou E., Stathopoulou M., Drakopoulos C., Soulikias A., Koutsouris P.: The complex structure of the expanding gaseous envelope of the Be star HD45910 (AX Mon), 210th Symposium of the International Astronomical Union, June 2002, Uppsala, Sweden
  21. Lyratzi E., Danezis E., Nikolaides D., Theodossiou E., Stathopoulou M., Kyriakopoulou A., Soulikias A.: The complex structure of Ha region in the gaseous envelope of Be V stars, 210th Symposium of the International Astronomical Union, June 2002, Uppsala, Sweden
  22. Danezis E., Lyratzi E., Nikolaides D., Theodossiou E., Stathopoulou M., Christou G., Soulikias A.:The complex structure of MgII region in the gaseous envelope of Be V stars, 210th Symposium of the International Astronomical Union, June 2002, Uppsala, Sweden
  23. Danezis E., Lyratzi E., Christou G., Theodossiou E., Stathopoulou M., Nikolaides D., Kyriakopoulou A.: Hyperionisation and emission phenomena in the coronal an post-coronal region of the moving atmosphere of the Oe star HD66811 (ζPup), 210th Symposium of the International Astronomical Union, June 2002, Uppsala, Sweden
  24. Danezis E., Nikolaidis D., Theodossiou E., Kosionidis A., Stathopoulou M., Lyratzi V., Draakopoulos C., Bourma P.: A simple model for the complex structure of moving atmospheric shells in Oe and Be stars. The example of HD 36861, some first conclusions,JENAM 2000, May 29-June 3, 2000 Moscow, Russia
  25. Danezis E., Nikolaidis D., Theodossiou E., Kosionidis A., Stathopoulou M., Lyratzi V., Drakopoulos C., Bourma P.: A simple model for the complex structure of moving atmospheric shells in Oe and Be stars. The example of HD 66811, some first conclusions,JENAM 2000, May 29-June 3, 2000 Moscow, Russia
  26. Danezis E., Nikolaidis D., Theodossiou E., Kosionidis A., Stathopoulou M., Lyratzi V., Drakopoulos C., Bourma P.: A simple model for the complex structure of moving atmospheric shells in Oe and Be stars. The example of HD 152408, some first conclusions,JENAM 2000, May 29-June 3, 2000 Moscow, Russia
  27. Danezis E., Nikolaidis D., Theodossiou E., Stathopoulou M., Grammenos Th., Kosionidis A.: A simple model for the complex structure of moving atmospheric shells in Oe and Be stars, Proceedings of the 4th Hellenic Astronomical Conference, Hellenic Astronomical Union, Samos, September 1999
  28. Danezis, E., Nikolaides, D., Theodossiou, E. Stathopoulou, M., Kosionidis, A.: Satellite spectral components and moving shells in the atmospheres of early type stars (The example of HD 175754). Proceedings of the 65th Czech and the 7th European Joint Conference, JENAM ’98. Prague, Czech Republic, September 1998
  29. Theodossiou, E. Laskarides, P. G., Danezis, E.: The UV spectrum of λOrionis,Proceedings of the 6th Hellenic Physics Conference. Komotini, 1993
  30. Laskarides, P. G., Danezis, E., Theodossiou, E.: A study of the shell structure of the binary system AX Monocerotis,Proceedings of the 6th Hellenic Physics Conference. Komotini, 1993
  31. Laskarides, P. G, Theodossiou, E., Danezis, E.: The far UV spectrum of AX Monocerotis.Proceedings 1st Panhellenic Astronomical Meeting, Athens, 21-23 September 1993
  32. Kontizas, M., Kontizas E., Danezis E.: Stars Counts on clusters of SMC, Comptes rendus sur les journees de Strasbourg 4eme reunion, Strasbourg 1982