newtxmath + Libertine + fontspec

Question

For a document I'm writing with XeLaTeX, I have to use Times New Roman as a main font. For math environment only, I'd like to use newtxmath with Libertine font. For my TexShop 2016 I installed Libertine using texhash and updmap-sys (as was described in the guide). So now there're many *.tfm files of Libertine in texfm-local. I also installed *.otf Libertine fonts directly into the system.

For this simple example

\documentclass[a4paper,14pt]{extreport}
\usepackage[no-math]{fontspec}
\usepackage[libertine]{newtxmath}
\setmainfont{Times New Roman}
\usepackage{polyglossia}
\setdefaultlanguage{english}
\begin{document}
\((5!)^5\)
\end{document}

in pdffonts I see

name                                 type              encoding         emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
HHHARJ+txsys                         Type 1C           Builtin          yes yes no       4  0
GMSUHV+LMRoman12-Regular             Type 1C           WinAnsi          yes yes no       5  0
CZQOLM+LMRoman10-Regular             Type 1C           WinAnsi          yes yes no       6  0
SRWENI+TimesNewRomanPSMT             CID TrueType      Identity-H       yes yes yes      8  0

There are no warnings in the log.

Could you please clarify the following questions

1. Am I right expecting only Libertine fonts in the pdffont's output? After all, only math environment is in the document.
2. Why do I see LMRoman and Times in the output? Shouldn't there be Libertine?
3. What is txsys?

And what can I do to fix this? As I understand, with a proper setup I should see only Libertine fonts in pdffont's output...

Any help is appreciated:)

Answer 1

N.B.: Before TL 2017 is released I advise against using XeTeX for any kind of math typesetting. There are a couple of problems.

It is much easier to just use unicode-math and the official math version of Libertine called Libertinus Math.

\documentclass[a4paper,14pt]{extreport}
\usepackage{unicode-math}
\setmainfont{Times New Roman}
\setmathfont{Libertinus Math}
\usepackage{polyglossia}
\setdefaultlanguage{english}
\begin{document}
\((5!)^5\)
\end{document}

It is even better to substitute everything by TeX Gyre Termes, a completely free Times clone.

\documentclass[a4paper,14pt]{extreport}
\usepackage{unicode-math}
\setmainfont{TeX Gyre Termes}
\setmathfont{TeX Gyre Termes Math}
\usepackage{polyglossia}
\setdefaultlanguage{english}
\begin{document}
\((5!)^5\)
\end{document}