Next GZ Hangout: 3rd of September, 3 pm GMT
The hangouts have returned from a midsummer hiatus! Our next hangout will be Tuesday, September 3rd, at 3 pm GMT. That’s 8 am PDT, 11 am EDT, 4 pm BST, 5 pm CET, 6 pm CAT. Unfortunately I think that’s 11 pm in Japan and midnight in Sydney, but hopefully we’ll have a hangout at a different time very soon!
Just before the hangout we’ll update this post with the embedded video, so you can watch it live from here. If you’re watching live and want to jump in on Twitter, please do! we use a term you’ve never heard without explaining it, please feel free to use the Jargon Gong by tweeting us. For example: “@galaxyzoo GONG dark matter halo“.
In the meantime, please feel free to leave a question in the comments below. See you soon!
Update: read a summary of the Hangout here: What is a Galaxy?… the Return
Galaxy Zoo 
Yay, Hangouts are back! 🙂
I have several questions, most triggered – directly or indirectly – by the Quench project.
1. In the absence of well-defined lines (either emission or absorption, or both) in the SDSS spectrum, how can you tell if a small blob – essentially indistinguishable from a point source – is a galaxy, or a star (or both; i.e. an overlap)? I posted six examples here, some are obvious, some not.
2. How would you go about deciding what the ‘double’ in SDSS J111954.25+330524.3 is – galaxy with a double nucleus/double bulge; late-stage merger; non-interacting galaxy-galaxy overlap; galaxy-star overlap; more? – from SDSS data alone (i.e. without new observations)? The two objects are separated by only ~1.7″, and each has as SDSS spectrum (there’s some write-up, and discussion, on it here).
3. In Quench Talk, meeka777 asked a question I think a great many zooites are keenly interested in (Beyond background information): “Does anyone have any recommendations on introductory astronomy info that might be a useful general foundation? I really want to contribute to the analysis, but I’m terribly under-qualified to do much besides look at the data on a surface level. I’ve been reading through all of the links posted and have learned a lot, but most of the posts in the results section are beyond my knowledge.”
4. AGS00000fq is a Quench Sample galaxy – a “post-quenched” galaxy, one that has “recently quenched star formation” – so, per this review, its spectrum must lack strong emission lines. Yet its spectrum is dominated by emission lines; even H-delta is in emission! How come?
4. The link for AGS00000fq directs to the GZ forum, but I guess you actually mean following link.: http://quenchtalk.galaxyzoo.org/#/subjects/AGS00000fq
I guess, that the spectrum doesn’t look like “post-quenched”, because it is maybe just one of the “control sample” galaxies.
PS: I don’t take part in this GZ side project.
My guess, that it might be a “control sample” galaxy, is wrong!
if I checked right
I write following comment afterwards.:
There are some further cases “Star or galaxy?” on the forum.:
Topic: “Spectrum class differences:DR7 versus DR8”:
http://www.galaxyzooforum.org/index.php?topic=279746.msg574220#msg574220
BTW, Jean had posted some comments in that topic and she might want to copy the other cases to the above forum topic.