Important note about publications
There are two important things to remember when venturing out into the open web. They both tie back to, fundamentally, that people suck online, especially when money is involved. But, astronomy is small enough that this is easy to beat, if you keep a few things in mind.
Which journals matter?
You may have heard that the "business model" of scientific publishing is broken, because the journals charge authors to publish and charge libraries for access to the publications. Astronomy is small enough that this isn't as big a deal as it is in other fields. In the US, the American Astronomical Society (the professional organization for astronomers) owns most of the journals (and I'd argue all of the important ones). So the money charged authors to publish is definitely not going to buy someone a boat. It covers costs for the Society and helps stabilize its budget.
You may have also heard that there are so-called "predatory journals" out there that publish crap articles with no review just so people (particularly young people) trying to publish a lot can get articles out with a lower bar to clear than in the main journals. I get academic spam advertising such journals at an astonishing rate. Once your AAS abstract is folded into ADS, you may also get such spam. All this spam seems to be originating in southeast Asia and include not just fake journals but fake conferences and fake conference proceedings. I feel sorry for legitimate astronomers in that part of the world trying to work and hold real conferences.
BUT astronomy is small enough that it's essentially impossible to start a new predatory journal and have any publications recognized by the worldwide community of astronomers.
Here are the most important journals in astronomy. Approach articles from anywhere else with caution.
- ApJ, Astrophysical Journal
- ApJL, Astrophysical Journal Letters
- ApJS, Astrophysical Journal Supplement Series
- AJ, Astronomical Journal
- PSJ, the Planetary Science Journal (the newest in the suite of AAS publishing)
- RNAAS, Research Notes of the American Astronomical Society (things too short for a journal article)
- PASP, Publications of the Astronomical Society of the Pacific (largely instrumentation/software, and same organization publishes conference proceedings; not owned by AAS)
- ARAA, Annual Reviews of Astronomy & Astrophysics (long review articles and autobiographical reminiscences; not owned by AAS)
- Science (high profile results, not just astronomy; not owned by AAS)
- Icarus (just planetary science; not owned by AAS)
Note that as of this writing, when you submit a paper to AAS journals, it goes into the same "hopper" ("AAS Journals") and the editors decide which journal it goes to.
- MNRAS, Monthly Notices of the Royal Astronomical Society (another professional-society-owned journal; they actually charge authors nothing for publications)
- AN, Astronomische Nachrichten (despite looking like German, this is Latin, and based in the UK)
- Nature (highest profile results, not just astronomy)
- Nature Astronomy (a spur off of Nature, because apparently they were getting "too many" astronomy submissions)
- A&A, Astronomy and Astrophysics
- A&ASS, Astronomy and Astrophysics Supplement Series
- New Astronomy Reviews (the newest journal; I'm not sure I have read many articles from here)
- Acta Astronomica
Rest of the world
- PASJ, Publications of the Astronomical Society of Japan
- PASA, Publications of the Astronomical Society of Australia
ADS does have articles from other places (like observatory publications); to first order, if you found it in ADS, it's probably legitimate. But, always be cautious with unrefereed material (conference proceedings, proposal abstracts, even multi-page documents that appear only on arXiv).
Where should you get articles?
I don't agree with predatory journal practices, but at least I can see how they make money. There are a large number of companies on the web whose business model I don't understand. They scrape up journal articles from other sites, or beg scientists to upload copies of their articles to their website, and then serve the articles as if they were the primary source of the article. I don't understand how the money flows here, but whatever.
You should get articles from ADS or from arXiv (astro-ph). You should approach anything else with extreme caution. And of course, it's free to access articles in arXiv, so you don't even need to go through journal paywalls to get the content. ADS has one page for each article that links together its apparitions in arXiv and the journal, if applicable (not everything on arXiv gets published in a journal).
Research Gate (deliberately not linked to here) appears as far as I can tell to be the largest company with this business. I get constant spam from the company and from other people through the site. People contacting me through the site use one of the easily available buttons on the site: "request a full text of this article." Everything I write, even conference proceedings that are more than just a poster, I post on arXiv. You can get all my full text there. Anyone who doesn't know this already is probably not an astronomer. I had to create a profile on Research Gate solely to turn off the spam, and my profile begs people to stop requesting full text, as everything is on arXiv, and that seems to have stemmed the flow somewhat.
There are several other companies attempting this business model. I get various levels of harassing mail insisting that I will increase my readership if I just upload all my papers to their company's website. I don't have time for that. Ain't no one got time for that. (Well...no one legitimate.) Only get papers from ADS or arXiv.
Seriously. Like, even Google Scholar doesn't provide results that are as consistently relevant and 'clean' as ADS. Only get papers from ADS or arXiv.