Solution in Brief
The \hfil
in the arguments of \item
s which actually render the bibitems is responsible for the horizontal white spaces.
Rendering of bibitems is done by the
\@lbibitem
command.
So, we need to redefine it. One way for this will be to use
\renewcommand
. But definitely, a smarter way will be to use
\patchcmd
.
\usepackage{etoolbox}
\makeatletter
\patchcmd{\@lbibitem}{\item[\hfil\NAT@anchor{#2}{\NAT@num}]}{\item[\NAT@anchor{#2}{\NAT@num}]}{}{}
\makeatother
The Full Code
\documentclass{article}
\bibliographystyle{apj_w_etal_3auth}
\usepackage[super,sort&compress]{natbib}
\usepackage{paralist}
\renewenvironment{thebibliography}[1]{%
\textsc{\textbf{References:}}
\let\par\relax\let\newblock\relax%
\inparaitem[{[}1{]}]}{\endinparaitem}
\usepackage{times}
\usepackage{etoolbox}
\makeatletter
\patchcmd{\@lbibitem}{\item[\hfil\NAT@anchor{#2}{\NAT@num}]}{\item[\NAT@anchor{#2}{\NAT@num}]}{}{}
\makeatother
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@article{einstein,
author = "Albert Einstein",
title = "{Zur Elektrodynamik bewegter K{\"o}rper}. ({German})
[{On} the electrodynamics of moving bodies]",
journal = "Annalen der Physik",
volume = "322",
number = "10",
pages = "891--921",
year = "1905",
DOI = "http://dx.doi.org/10.1002/andp.19053221004"
}
@book{latexcompanion,
author = "Michel Goossens and Frank Mittelbach and Alexander Samarin",
title = "The \LaTeX\ Companion",
year = "1993",
publisher = "Addison-Wesley",
address = "Reading, Massachusetts"
}
@article{belloche2014detection,
title={Detection of a branched alkyl molecule in the interstellar medium: iso-propyl cyanide},
author={Belloche, Arnaud and Garrod, Robin T and M{\"u}ller, Holger SP and Menten, Karl M},
journal={Science},
volume={345},
number={6204},
pages={1584--1587},
year={2014},
publisher={American Association for the Advancement of Science}
}
@article{mcnally1989anxiety,
title={Is anxiety sensitivity distinguishable from trait anxiety? Reply to Lilienfeld, Jacob, and Turner (1989).},
author={McNally, Richard J},
year={1989},
publisher={American Psychological Association}
}
\end{filecontents}
\begin{document}
\nocite{*}
\bibliography{\jobname}
% \show\bibitem
% \makeatletter
% \show\@lbibitem
% \makeatother
\end{document}
The Output

The Sleuthing Activity
An inspection of the .bbl file shows that each bibliographic entry
is rendered by a \bibitem
.
So, we issue a \show\bibitem
inside our source. This gives:
\bibitem=\long macro:
->\@ifnextchar [{\@lbibitem }{\@lbibitem []}.
We delve deeper and look inside \@lbibitem
.
\makeatletter
\show\@lbibitem
\makeatother
gives:
\@lbibitem=macro:
[#1]#2->\if \relax \@extra@b@citeb \relax \else \@ifundefined {br@#2\@extra@b@c
iteb }{}{\@namedef {br@#2}{\@nameuse {br@#2\@extra@b@citeb }}}\fi \@ifundefined
{b@#2\@extra@b@citeb }{\def \NAT@num {}}{\NAT@parse {#2}}\def \NAT@tmp {#1}\ex
pandafter \let \expandafter \bibitemOpen \csname NAT@b@open@#2\endcsname \expan
dafter \let \expandafter \bibitemShut \csname NAT@b@shut@#2\endcsname \@ifnum {
\NAT@merge >\@ne }{\NAT@bibitem@first@sw {\@firstoftwo }{\@ifundefined {NAT@b*@
#2}{\@firstoftwo }{\expandafter \def \expandafter \NAT@num \expandafter {\the \
c@NAT@ctr }\@secondoftwo }}}{\@firstoftwo }{\global \advance \c@NAT@ctr \@ne \@
ifx {\NAT@tmp \@empty }{\@firstoftwo }{\@secondoftwo }{\expandafter \def \expan
dafter \NAT@num \expandafter {\the \c@NAT@ctr }\global \NAT@stdbsttrue }{}\bibi
tem@fin \item [\hfil \NAT@anchor {#2}{\NAT@num }]\global \let \NAT@bibitem@firs
t@sw \@secondoftwo \NAT@bibitem@init }{\NAT@anchor {#2}{}\NAT@bibitem@cont \bib
item@fin }\@ifx {\NAT@tmp \@empty }{\NAT@wrout {\the \c@NAT@ctr }{}{}{}{#2}}{\e
xpandafter \NAT@ifcmd \NAT@tmp (@)(@)\@nil {#2}}.
Which, I must say, is a mouthful and somewhat difficult to
perceive. So, we open the natbib.sty
file in an editor and search
for \@lbibitem
.
The subsequent lines show how the bibliographic
entry is being rendered. The line,
\item[\hfil\NAT@anchor{#2}{\NAT@num}]
raises our suspicion and tweaking with this confirms that we have hit the
right point.
Further Reading
If you want to know more about
\patchcmd
, please take a look at this wonderful answer.