Curriculum Vitae
PERSONAL INFORMATION
Family name, First name: Pappas, Georgios
Researcher unique identifier(s) (such as ORCID, Research ID, etc. ...): http://orcid.org/0000-0003-3344-3759 , http://inspirehep.net/author/profile/G.Pappas.1 , http://www.scopus.com/authid/detail.url?authorId=56365236000
Date of birth: 02/01/1978
URL for web site: https://www.physics.auth.gr/en/sections/1/people/243
EDUCATION
28/11/2005 – 10/09/2012 PhD
Physics Department, National Kapodistrian University of Athens, Greece.
12/12/2001 – 28/02/2005 Master
Physics Department, National Kapodistrian University of Athens, Greece.
CURRENT POSITION
10/01/2019 – present Assistant Professor
Department of Physics, Aristotle University of Thessaloniki, Greece.
PREVIOUS POSITIONS
01/03/2018 – 31/12/2018 Postdoc
Department of Physics, "Sapienza" University of Rome, Italy.
01/11/2017 – 31/01/2018 Research Fellow
School of Mathematical Sciences, University of Nottingham, United Kingdom.
01/09/2016 – 01/09/2017 Postdoc
Department of Physics, Instituto Superior Tecnico, Lisbon, Portugal.
05/08/2015 – 06/07/2016 Postdoctoral Research Associate
Department of Physics & Astronomy, University of Mississippi, United States of America.
01/01/2014 – 31/03/2015 Research Fellow
School of Mathematical Sciences, University of Nottingham, United Kingdom.
01/04/2013 – 31/12/2013 Postdoc
Faculty of Physics, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Italy.
15/09/2012 – 31/03/2013 Postdoc
Section of Theoretical Astrophysics, Eberhard Karls University of Tuebingen, Germany.
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FELLOWSHIPS AND AWARDS
15/09/2012 – 15/02/2013 DAAD Fellowship, Section of Theoretical Astrophysics, Eberhard Karls University of Tuebingen, Germany.
2016 FCT Post-Doctoral Fellowship (2016 call, SFRH/BPD/119750/2016) - Declined due to bureaucracy
2018 NAOJ Visiting Fellow - Fellowship for visiting NAOJ in Tokyo and collaboration.
TEACHING ACTIVITIES
2001 - 2005 (NKUA) Supervision and teaching of laboratory courses on Mechanics, Thermodynamics, Waves/Optics, at the Physics Department at the National Kapodistrian University of Athens, Greece.
2019 - present (AUTh) Teaching the elective undergraduate course on Astrophysics at the Physics Department at the Aristotle University of Thessaloniki, Greece.
2019 - present (AUTh) Teaching the elective undergraduate course on Fluid Mechanics at the Physics Department at the Aristotle University of Thessaloniki, Greece.
2020 - present (AUTh) Teaching the elective undergraduate course on Plasma Physics at the Physics Department at the Aristotle University of Thessaloniki, Greece.
2021 - present (AUTh) Teaching the compulsory undergraduate course on Astronomy and Astrophysics at the Physics Department at the Aristotle University of Thessaloniki, Greece.
2019 - present (AUTh) Teaching the elective graduate course on Astrophysics for the Masters program on Computational Physics of the Physics Department at the Aristotle University of Thessaloniki, Greece.
2019 - 2020 (AUTh) Teaching the elective graduate course on Special Topics on General Relativity for the Masters program on Subatomic physics and Applications of the Physics Department at the Aristotle University of Thessaloniki, Greece.
INSTITUTIONAL RESPONSIBILITIES
Academic years, 2004 – 2012 I have participated in the organization of an internal seminar (Astro Friday's Meetings) at the Astrophysics section of the Physics department in the University of Athens, Greece. I took a break from participating to the organisation of the seminar during the period of my obligatory military service in the Greek army (academic year 2009-2010).
MEMBERSHIPS OF SCIENTIFIC SOCIETIES
Since 2010 Member of the “Hellenic Society on Relativity, Gravitation and Cosmology” (HSRGC), Greece.
2016 - 2021 Member of the American Physical Society.
CAREER BREAKS IN RESEARCH
15/08/2009 – 15/04/2010 Obligatory military service in the Greek Army. During my military service I was stationed in Thebes, Samos and Athens, in Greece.
SUMMARY
I was born in Athens in 1978. In 1996 I joined the Physics Department of the National and Kapodistrian University of Athens (University of Athens onwards), Greece, where I received a degree in Physics. From the same Department I have received a Master degree in Astrophysics (2005) and a PhD in Physics (2012). The work for both my Master thesis and PhD thesis was supervised by Assistant Prof. Theocharis Apostolatos. After I was awarded my PhD diploma in September 2012, I moved to the University of Tuebingen, Germany, under a DAAD scholarship, to work in the group of Prof. K. Kokkotas on analytic spacetimes and compact objects. In April 2013, I moved to Trieste, Italy, and then in January 2014 to Nottingham, UK, to work in the group of Associate Prof. T. Sotiriou on compact objects in General Relativity and in alternative theories of gravity. In August 2015 I moved to Oxford, MS, in the US to work for Associate Prof. Emanuele Berti at the University of Mississippi where I stayed until the summer of 2016. In August 2016 I moved to Lisbon, Portugal to join the gravity group (GRIT/CENTRA) at Instituto Superior Tecnico. In early 2017, I was awarded a 3+3 years FCT Post-Doctoral Fellowship (2016 call), which I had to let go due to bureaucracy. From November 2017 until February 2018 I spent a short period as a Research Fellow at the University of Nottingham and between March and December of 2018, I was part of the DarkGra group of Assistant Prof. Paolo Pani at the Sapienza University of Rome. Since 2019 I have been an Assistant Professor at the Aristotle University of Thessaloniki, Greece. Currently, I am a member of AUTh's gravitational waves group and as such participate in VIRGO and LISA. In recent years I also participated in the COST actions GWVerse on gravitational waves and PHAROS on neutron stars.
I have published 24 papers in major international journals (2 in Physical Review Letters, 1 in The Astrophysical Journal Letters, 1 in The Astrophysical Journal, 11 in Physical Review D, 1 in the Physical Review D Letters, 5 in the Monthly Notices of the Royal Astronomical Society, 1 in Neurocomputing and 2 in Classical and Quantum Gravity), 1 Book Chapter on a volume on Neutron Stars, and 3 papers in refereed conference proceedings (Journal of Physics: Conference Series). I also have at the moment 11 papers from large collaborations. A list of my publications is given below.
Our paper on universal properties of neutron star multipole moments, published in Physical Review Letters (Phys.Rev.Lett. 112 (2014) 121101), was selected as an Editors' Suggestion and received some media attention with articles on Science Daily, Phys.org, and Daily News, while our recent paper on the astrophysical applications of the post-TOV formalism was also selected as an Editors' Suggestion.
Research interests
Compact Objects: Structure and global properties of compact objects related to the multipole moments spectrum and the surrounding spacetime. Universal properties (EOS independent) of compact objects and no-hair-like structure of their multipole moments.
Multipole moments in General Relativity: Geroch-Hansen-Fodor moments. Application in constructing analytic spacetimes suitable for astrophysical applications and their use as probing tools for astrophysical systems such as XRBs.
Stationary axisymmetric spacetimes in GR: Methods for generating solutions of the Einstein field equations in vacuum. Applications:
- Connection of the Ernst potential to Astrophysical sources using multipole moments.
- Construction of analytic metrics to describe the exterior of compact objects, with application to astro- physical problems such as rotating neutron stars, accretion disks and QPOs.
- Probe issues concerning the nature of compact objects and their deviation from classical GR solutions like Schwarzschild and Kerr.
Multipole moments beyond GR: Definition of multipole moments in alternative theories of gravity, such as for example, scalar-tensor theories of gravity. Multipolar structure of compact objects in alternative theories and observational implications.
Rotating spacetimes beyond GR: Rotating spacetimes in alternative theories of gravity. Testing GR and alternative theories using astrophysical observations.
Exotic Compact Objects, Black Hole Mimickers, and Gravitational Waves: Ultra-compact objects within and beyond GR that can emulate BHs in their compactness and possible signatures that could distinguish them from BHs, such as differences in their QNMs that could be picked up by GW spectroscopy or inspiral GW signals. GW tests of GR, BHs, the Kerr hypothesis and theories beyond GR.
Gravitational lensing from compact objects, Black Hole Shadows, and tests of GR and the Kerr nature of BHs: Imaging of ultra-compact objects such as black holes or exotic alternatives. Calculation of shadows, chaotic lensing and other lensing characteristics that may be used as probes of the nature of the compact object and test GR.
PUBLICATIONS IN LEADING INTERNATIONAL PEER-REVIEWED JOURNALS
14) George Pappas, "An accurate metric for the spacetime around rotating neutron stars", MNRAS 466 (2017) 4381 (arXiv:1610.05370 [gr-qc]).
13) Kostas Glampedakis, George Pappas, Hector O. Silva, Emanuele Berti, "Astrophysical applications of the post-Tolaman-Oppenheimer-Volkoff formalism", 2016 Phys. Rev. D 94, 044030 (arXiv:1606.05106 [gr-qc]).
12) David Tsang, and George Pappas, "Self-Trapping of Diskoseismic Corrugation Modes in Neutron Star Spacetimes", 2016 ApJ, 818, L11 (arXiv:1511.01948 [astro-ph.HE]).
11) George Pappas, "Unified description of astrophysical properties of neutron stars independent of the equation of state", MNRAS 454 (2015) 4066-4084 (arXiv:1506.07225 [astro-ph.HE]).
10) George Pappas, and Thomas P. Sotiriou,"Geodesic properties in terms of multipole moments in scalar-tensor theories of gravity", MNRAS 453 (2015) 2862-2876 (arxiv:1505.02882[gr-qc]).
9) Kostas Glampedakis, George Pappas, Hector O. Silva, Emanuele Berti, "Post-Tolman-Oppenheimer-Volkoff formalism for relativistic stars", Phys. Rev. D 92 (2015) 024056 (arxiv:1504.02455[gr-qc]).
8) George Pappas, and Thomas P. Sotiriou, "Multipole moments in scalar-tensor theory of gravity", Phys. Rev. D 91, 044011 (2015) (arXiv:1412.3494 [gr-qc]). Citations: 1/1 (based on INSPIRE record)
7) Kent Yagi, Leo C. Stein, George Pappas, Nicolas Yunes, Theocharis A. Apostolatos, “Why I-Love-Q: Explaining why universality emerges in compact objects”, Phys.Rev. D 90 (2014) 063010 (arXiv:1406.7587 [gr-qc]). Citations: 7/8 (based on INSPIRE record)
6) Kent Yagi, Koutarou Kyutoku, George Pappas, Nicolas Yunes, Theocharis A. Apostolatos, “Effective no-Hair Relations for Neutron Stars and Quark Stars: Relativistic Results”, Phys.Rev. D89 (2014) 124013 (arXiv:1403.6243 [gr-qc]). Citations: 14/16 (based on INSPIRE record)
5) George Pappas, and Theocharis A. Apostolatos, “Effectively universal behavior of rotating neutron stars in general relativity makes them even simpler than their Newtonian counterparts”, Phys.Rev.Lett. 112 (2014) 121101 (arXiv:1311.5508 [gr-qc]). Citations: 18/21 (based on INSPIRE record)
4) George Pappas, and Theocharis A. Apostolatos, “An all-purpose metric for the exterior of any kind of rotating neutron star”, MNRAS 429 (2013) 3007-3024 (arXiv:1209.6148 [gr-qc]). Citations: 2/5 (based on ADS record)
3) George Pappas, and Theocharis A. Apostolatos, "Revising the multipole moments of numerical spacetimes, and its consequences", 2012 Phys. Rev. Lett. 108 (2012) 231104 , (arXiv:1201.6067 [gr-qc]). Citations: 23/28 (based on ADS record)
2) George Pappas, “What can QPOs tell us about the structure of the corresponding compact objects?”, MNRAS 422 (2012) 2581-2589, (arXiv:1201.6071 [astro-ph.HE]). Citations: 9/14 (based on ADS record)
1) George Pappas, and Theocharis A. Apostolatos, “Faithful transformation of quasi-isotropic to Weyl-Papapetrou coordinates: a prerequisite to compare metrics”, Class. Quantum Grav. 25 (2008) 228002 (extended version arXiv:0803.0602v1 [gr-qc]). Citations: 1/3 (based on ADS record)
PUBLICATIONS IN PEER-REVIEWED CONFERENCE PROCEEDINGS
3) Theocharis A. Apostolatos, George Pappas, and Katerina Chatziioannou, “A Newtonian problem as an insightful tool for the behavior of gravitational-wave sources”, J.Phys.: Conf. Ser. 453 (2013) 012001. Citations: 0/0 (based on ADS record)
2) George Pappas, “Matching of analytical and numerical solutions for neutron stars of arbitrary rotation”, J. Phys.: Conf. Ser. 189 (2009) 012028, (arXiv:1201.6055 [gr-qc]). Citations: 2/6 (based on ADS record)
1) Thomas P. Sotiriou, and George Pappas, “Extending Sibgatullin's ansatz for the Ernst potential to generate a richer family of axially symmetric solutions of Einstein's equations”, J. Phys.: Conf. Ser. 8 (2005) 23, (arXiv:gr-qc/0504122). Citations: 0/5 (based on ADS record)
Preprints
1) George Pappas, and Theocharis A. Apostolatos, “Multipole Moments of numerical spacetimes”, arXiv:1211.6299 [gr-qc]. Citations: 1/2 (based on ADS record)
Conferences, Talks and Schools
- Conferences. I have attended the following conferences, where I presented my work by giving a talk:
8) NEB XVII “Recent Developments in Gravity", 19-22 September 2016, Mykonos, Greece. Talk title: “The spacetime around compact objects and astrophysical observables".
7) Conference "Compact Stars and Black Holes", 7-9 July 2015, Tübingen, Germany. Invited speaker. Talk title: "An EOS independent description of astrophysical properties of neutron stars".
6) Workshop on "(Non-)Universal properties of Neutron Stars", 18-20 May 2015, held at the Center for Applied Space Technology and Micro-Gravity (ZARM) in Bremen, Germany. Talk title: "Multipole moments: from GR to scalar-tensor theory. Connection to Astrophysical observables".
5) NEB XVI “Recent Developments in Gravity", 17-20 September 2014, Mykonos, Greece. Talk title: “Why I-Love-Q?".
4) 558th WE-Heraeus-Seminar on “The Strong Gravity Regime of Black holes and Neutron stars”, 31st March to 4th April, 2014, Physikzentrum Bad Honnef, Germany. Talk title: "Universal behavior of neutron star multipole moments".
3) NEB XV “Recent Developments in Gravity", 20-23 June 2012, Chania, Greece. Talk title: “Revising the Multipole Moments of numerical spacetimes" (arXiv:1211.6299 [gr-qc]).
2) NEB XIII “Recent Developments in Gravity", 3-6 June 2008, Thessaloniki, Greece. Talk title: “Matching of Analytical and Numerical Solutions for Neutron Stars of Arbitrary Rotation".
1) NEB XI “Recent Developments in Gravity", 2-5 June 2004, Lesvos island, Greece. Talk title: “On the Multipole Moments of Axially Symmetric Spacetimes".
I have also attended the following conferences/workshops without contributing a talk: 6) eXtreme Gravity Workshop, 20-22 August 2015 in Bozeman Montana, USA, 5) Lorentz Center workshop on "Compact objects as Astrophysical and Gravitational probes", 2-6 February 2015, Leiden, Netherlands. 4) GGI conference on “The structure and signals of neutron stars, from birth to death”, 24-28 March 2014, Florence, Italy. 3) NEB XII “Recent Developments in Gravity", 29 June - 2 July 2006, Nafplio, Greece. 2) NEB X “Recent Developments in Gravity", 31 May - 3 June 2002, Chalkidiki, Greece. 1) NEB IX “Recent Developments in Gravity'', September 2000, Ioannina, Greece.
- Invited talks. On several occasions I have been invited to present my work and new results to other institutes.
1) University of Tübingen, Institut fur Astronomie & Astrophysik, November 24th 2010, Tübingen, Germany. Talk title: “The spacetime exterior to rotating neutron stars and the possibility of constraining the equation of state from QPOs".
2) SISSA, November 27th 2012, Trieste, Italy. Talk title: “Relativistic precession of orbits in the spacetime around neutron stars”.
3) API Amsterdam, December 8th 2012, Amsterdam, Netherlands. Talk title: “Relativistic precession around neutron stars”.
4) University of Tübingen, Institut fur Astronomie & Astrophysik, July 15th 2014, Tübingen, Germany. Talk title: “Universal behaviour of neutron star multipole moments (I-Love-Q relations)”.
5) NESTAR web conference, ZARM, Universität Bremen, August 18th 2014. Talk title: “Universal behaviour of neutron star multipole moments (I-Love-Q relations)”.
6) Colloquium seminar, at the department of Physics and Astronomy, University of Mississippi, USA, November 18th 2014. Talk title: "Neutron Stars: Global Properties and Properties of orbits around them".
7) Gravity seminar at STAG Research Centre, University of Southampton, UK, December 11th 2014. Talk title: "Doing astrophysics around neutron stars: Their global properties and the properties of orbits around them".
8) Gr@v group seminar at the University of Aveiro, Aveiro, Portugal, November 30th 2016. Talk title: "The spacetime around neutron stars and astrophysical observables".
- Talks and Seminars. I have occasionally been invited to present my work to collaborating groups, to present to colleagues novel results that appeared in the news and were related to my research interests or even lecture students. In this framework I have given the following talks/seminars:
1) University of Athens, March 11th 2005, Athens, Greece. Talk title: “Maximum masses of white dwarfs and neutron stars" (Astro Friday's Meetings).
2) University of Athens, January 13th 2006, Athens, Greece. Talk title: “The concept of acoustic analogues of black holes" (Astro Friday's Meetings).
3) University of Athens, November 4th 2011, Athens, Greece. Talk title: “On the recent measurement of the distance, the mass and the spin of Cygnus X-1" (Astro Friday's Meetings).
4) SFB/TR7 meeting at MPA in Garching 16th and 17th of October, 2012 Garching, Germany. Talk title: "Revising the Multipole Moments of numerical spacetimes".
5) Theoretical Astrophysics and Computational Physics Seminar at the Institute for Astronomy and Astrophysics, Univeristy of Tuebingen, October 30th 2012, Tuebingen, Germany. Seminar title: "Some topics on compact objects and the spacetime around them".
6) SFB/TR7 Video Seminar at the University of Tuebingen, November 19th 2012, Tuebingen, Germany. Talk title: "Relativistic precession of orbits around neutron stars".
7) CENTRA group seminar at Instituto Superior Tecnico, Lisbon, Portugal, October 27th 2016. Talk title: "The spacetime around neutron stars and astrophysical observables".
-Schools. I have attended the following international schools:
1) 42nd Karpacz Winter School of Theoretical Physics, “Current Mathematical Topics in Gravitation and Cosmology", Ladek, Poland, 6-11 February 2006.
2) 4th Aegean Summer School, “BlackHoles", Mytilene, Island of Lesvos, Greece, 17-22 September 2007.
3) 2008 Onassis Lectures in Physics, “COSMOLOGY: AN ASTROPHYSICAL PERSPECTIVE", June 30 - July 4, Heraklion, Greece.
Journal Refereeing
I have refereed several papers and I am currently an active referee for the international peer-reviewed journals Physical Review Letters, Physical Review D, The Astrophysical Journal, International Journal of Modern Physics D, European Physical Journal C, General Relativity and Gravitation, Gravitation and Cosmology, Europhysics Letters and Astrophysics and Space Science. (link)
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