My research mainly focuses on the exploration of the gas and dust properties in nearby galaxies. I use observations mainly in optical and infrared/submm wavelengths as well as radiative transfer models in order to simulate the optical and infrared appearance of galaxies. I am also interested in astronomical instrumentation in optical telescopes (Aristarchos telescope, Kryoneri telescope) and infrared observatories (Herschel-HIFI) as well as in optical and quantum telecommunications.
Radiative Transfer Modeling
Left: A typical model galaxy in the B-band shown at various inclination angles (indicated on top of each model image). Right: Mapping of the optical depth as a function of the inclination angle (red regions show the optically thick parts while blue regions show the optically thin parts of the galaxy; Xilouris et al. 1999).
I have performed Radiative Transfer calculations in spiral galaxies. The model that I use assumes 3D geometry and is based on the method described in Kylafis & Bahcall (1987) utilizing the algorithm of scattered intensities to take into account absorption and multiple scattering of the stellar light by the dust grains. The results of this study are presented in a series of papers, [e.g. Xilouris et al., 1997; 1998; 1999; Dasyra et al. 2005; Misiriotis et al. 2006].
Infrared properties of nearby galaxies
The nearby spiral galaxy M33 observed by Herschel Space Observatory (HerM33es; Xilouris et al. 2012).
I have analyzed infrared/sub-millimeter observations of nearby galaxies using data coming from either ground-based telescopes (JCMT, IRAM-30m) or space telescopes (IRAS, ISO, Spitzer, Akari, Herschel). I am a member of the Herschel M33 Extended Survey (HerM33es), the Herschel Virgo Cluster Survey (HeViCS), the Fornax Virgo Cluster Survey (HeFoCS), the Herschel Comprehensive (U)LIRG Emission Survey (HerCULES), the Herschel Observations of Edge-on Spirals (HEROES) and the New HErschel Multi-Wavelength Extragalactic Survey of Edge-on Spirals (NHEMESES). Selected publications are: Davies et al. 2013, Xilouris et al. 2012, Kramer et al. 2011, Davies et al. 2010, Zhu et al. 2009, Xilouris et al. 2004a, 2004b.
Luminous Infrared Galaxies
Three-phase LVG modelling of the SLEDs of Arp193 and NGC6240 (Papadopoulos et al. 2014)
I study the properties of the dense molecular clouds and dust in (U)LIRGs using observations from ground-based telescopes (JCMT, IRAM-30m) and Herschel Space Observatory. I am a member of the Herschel Comprehensive (U)LIRG Emission Survey (HerCULES) and PI of a 3-year program (EU/Greece funded; Aristeia) entitled "A Step in the Dark: The Dense Molecular Gas in Galaxies (DeMoGas)", (Total budget: €210,000) . Check out this video (in Greek only) from the "2012 Research Projects" funded by the John S. Latsis Public Benefit Foundation. Selected publications are: Papadopoulos et al. 2012a, 2012b, Ivison et al. 2011, Gonzalez-Alonso et al. 2010, van der Werf et al. 2010, Papadopoulos et al. 2010.
Properties of the ISM
The field of the G6.4-0.1 supernova remnat in the [SII] filter with the 1400 MHz radio emission overploted (blue contours). Observations were obtained with the 0.3 m Schmidt-Cassegrain telescope at Skinakas Observatory, Crete, Greece (Mavromatakis et al. 2004)
I have been involved in studies of the ISM (detection of Galactic Supernova Remnants (SNRs) and Planetary Nebulae (PNe) at optical wavelengths). Selected publications are: Mavromatakis et al. 2004, Boumis et al. 2006, Boumis et al. 2008, Boumis et al. 2009.
Near Earth Objects
A Near Earth Object Impact on the Moon (astrist's impression)
I am a member of the NELIOTA team (Technical Manager of the project). NELIOTA aims to determine the distribution and frequency of small near-earth objects (NEOs) by monitoring lunar impact flashes. The NELIOTA project has established an operational system that started monitoring the Moon for faint NEO impacts in early 2017, using the 1.2m Kryoneri telescope, located in the Northern Peloponnese, in Greece. Selected publications are: Xilouris et al. 2018, A&A, 619, 141; Bonanos et al. 2018, A&A, 612, 76; Liakos et al., 2020, A&A, 633, 112.