Mrthfx

I am writing a paper on overleaf supposedly in ApJ (Astrophysical Journal) format. I have my .bib file independently made utilizing JabRef on ADS website and uploaded to the project in Overleaf. But it seems that in-text citations do not appear in the final version after compiling. In particular, here is my short version of the code:

documentclass[twocolumn,trackchanges]{aastex61}



usepackage{natbib}



usepackage{graphicx}

usepackage{latexsym}

usepackage{amssymb}

usepackage{longtable}

usepackage{epsf}



begin{document}

.

.

.

section{Methodology and Analyses}  label{Section 2}

....This includes absorbers selected for the presence of ion{C}{4}

$lambda lambda1548.1,1550.7$, ion{Mg}{2} $lambdalambda2796.3,2803.5$

resonance-line doublets and Lyman limit absorption, which do not also 

qualify as DLA systems. For a complete review on the subject refer to 

citet{2005ARA&A..43..861W}. 



bibliographystyle{ApJ}

bibliography{my_References}

.

.

.

end{document} 

Here is the Error Message:

(no line number): This is BibTeX, Version 0.99d (TeX Live 2016/Debian)
Capacity: max_strings=100000, hash_size=100000, hash_prime=85009 The
top-level auxiliary file: sim_DLA_Paper.aux I couldn't open style file
ApJ.bst
---line 126 of file sim_DLA_Paper.aux : bibstyle{ApJ : } I'm skipping whatever remains of this command I found no style
file---while reading file sim_DLA_Paper.aux You've used 46 entries,
0 wiz_defined-function locations,
178 strings with 2287 characters, and the built_in function-call counts, 0 in all, are:
= -- 0

-- 0 < -- 0
+ -- 0
- -- 0
* -- 0 := -- 0 add.period$ -- 0 call.type$ -- 0 change.case$ -- 0 chr.to.int$ -- 0 cite$ -- 0 duplicate$ -- 0 empty$ -- 0 format.name$
-- 0 if$ -- 0 int.to.chr$ -- 0 int.to.str$ -- 0 missing$ -- 0 newline$ -- 0 num.names$ -- 0 pop$ -- 0 preamble$ -- 0 purify$ -- 0 quote$ -- 0 skip$ -- 0 stack$ -- 0 substring$ -- 0 swap$ -- 0 text.length$ -- 0
text.prefix$ -- 0 top$ -- 0 type$ -- 0 warning$ -- 0 while$ -- 0
width$ -- 0 write$ -- 0 (There were 2 error messages)
./sim_DLA_Paper.tex:75: Package natbib Warning: Citation
2005ARA&A..43..861W' on page 2 undefined on i nput line 75.
./sim_DLA_Paper.tex:80: Package natbib Warning: Citation
2003MNRAS.342..962S' on page 2 undefined on i nput line 80.

Package natbib Warning: Citation `2003JApA...24...51G' on page 2
undefined on i nput line 80.

Package natbib Warning: Citation `2005MNRAS.356..778S' on page 2
undefined on i nput line 80.

Package natbib Warning: Citation 1974A&A....32..391P' on page 2
undefined on i nput line 80. ./sim_DLA_Paper.tex:81: Package natbib
Warning: Citation2005CSci...88.1088B' on page 2 undefined on i nput
line 81. ./sim_DLA_Paper.tex:83: Package natbib Warning: Citation
`2011MNRAS.416.1215R' on page 2 undefined on i nput line 83.

Package natbib Warning: Citation `2016A&A...596A..97D' on page 2
undefined on i nput line 83.

Package natbib Warning: Citation 2016MNRAS.460.2675R' on page 2
undefined on i nput line 83. ./sim_DLA_Paper.tex:85: Package natbib
Warning: Citation2014MNRAS.445..581H' on page 3 undefined on i nput
line 85.

Here is the the first two entries of .bib file:

% Encoding: UTF-8



@Article{2005ARA&A..43..861W,

  author  = {{Wolfe}, A.~M. and {Gawiser}, E. and {Prochaska}, J.~X.},

  title   = {{Damped Ly {$alpha$} Systems}},

  journal = {araa},

  year    = {2005},

  volume  = {43},

  pages   = {861-918},

  month   = sep,

  adsnote = {Provided by the SAO/NASA Astrophysics Data System},

  adsurl  = {http://adsabs.harvard.edu/abs/2005ARA%26A..43..861W},

  doi     = {10.1146/annurev.astro.42.053102.133950},

  eprint  = {astro-ph/0509481},

  file    = {:2005ARA&A..43..861W - Damped Ly $_alpha$ Systems.pdf:PDF},

}



@Article{2005MNRAS.364.1467Z,

  author   = {{Zwaan}, M.~A. and {van der Hulst}, J.~M. and {Briggs}, F.~H. and {Verheijen}, M.~A.~W. and {Ryan-Weber}, E.~V.},

  title    = {{Reconciling the local galaxy population with damped Lyman {$alpha$} cross-sections and metal abundances}},

  journal  = {mnras},

  year     = {2005},

  volume   = {364},

  pages    = {1467-1487},

  month    = dec,

  adsnote  = {Provided by the SAO/NASA Astrophysics Data System},

  adsurl   = {http://adsabs.harvard.edu/abs/2005MNRAS.364.1467Z},

  doi      = {10.1111/j.1365-2966.2005.09698.x},

  eprint   = {astro-ph/0510127},

  file     = {:2005MNRAS.364.1467Z - Reconciling the local galaxy population with damped Lyman $_alpha$ cross-sections and metal abundances.pdf:PDF},

  keywords = {surveys, galaxies: ISM, quasars: absorption lines, galaxies: statistics, radio lines: galaxies},

}

I can see that .bib file is contained citations in the form of MNRAS. I think they should instead be all ApJ. But, it is really a long file and I don't know if I need to manipulate all sources one by one. When I change the option ApJ to mnras in the following command bibliographystyle{}, in-text citations appear but why is that? Why style ApJ is not recognized?

The error message

bibstyle{ApJ : } I'm skipping whatever remains of this command

tells you that the bibliography style is unknown to overleaf. You need to add a file apj.bst to your project, that means add it into the same directory you have your TeX file.

You can for example find a link to apj.bst on the website of aastex in section 2.13.2 Specifying Bibliographic and Citation Information.