Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Topics - JeanTate

Pages: [1] 2 3 ... 19
1
Object of the Day / Wednesday, 9 July, 2014: Colors, Spray
« on: July 09, 2014, 12:47:21 am »
Continuing in the 'good old days' style I used in last week's OOTD (Wednesday, 2 July, 2014: Depth):



This is centered on SDSS J134814.32+152538.1, which has a spectroscopic redshift of 0.057. I'd love to be able to say it - or its northern companion - has been posted before, by ... but I can't!  :'( I do not know how to easily go about finding all the relevant DR7, DR8, and DR9 ObjIds (if I had them, I could search this forum), and even if I did, I do not know how to search GZ Talk for any threads, posts, or comments on any AGZ object/field which may include them.

The bottom half of the northern galaxy (SDSS J134814.77+152550.2) is a very different color than the top half; is that because there's a tidal tail of thick dust across it (and none over the top half)? If so, why isn't the bottom galaxy equally red?

And what's SDSS J134814.58+152541.3, the pure red star in between? Is it just a foreground (Milky Way) very red star (M class perhaps)? or something associated with the merger (heavily reddened)? or ...?

Actually, I couldn't resist including another amazing galaxy:



That's SDSS J011821.34-025856.1, and it was noted by  trevor allen faller_ErrorDupUsername in GZ Talk on December 7 2012 8:17 PM. On July 7 2014 10:45 PM, zooite mendocinosunrise independently discovered it, saying (in GZ Talk) "what are the two jets coming out of the left side of this galaxy?" Super-zooite Budgieye followed up, and noted its resemblance to M82 (see the Bulge or outflow of gas? GZ Talk thread).

Zooite trevor faller posted this here, in the GZ forum, on December 09, 2012, 01:16:14 am: HALO?

Quote from: trevor faller
http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237657065793650763  dont know if this is a foreground irregular with the flat galaxy showing through or a rather large halo

A few hours' later, paulrogers replied:

Quote from: paulrogers
Good question!  And I'll pose another possibility--perhaps it's the remnant dust cloud from a local supernova's planetary nebula that happens to be in our line of sight.

Unfortunately we have no spectra.  If we had separate spectra/redshifts from the eastern blue bit and the southern red bit we could determine if they're the same distance away and associated.  NED gives a single redshift (Redshift:  0.026635 +/- 0.000150) but Skyserver has none.

What do you think?

Oh, more eye-candy; M82 (source):


2
Object of the Day / Wednesday, 2 July, 2014: Depth
« on: July 02, 2014, 12:18:59 am »
Back in the good ol' days, Object of the Day featured a single image, often with a single object of note. Today's OotD is a return to that style.



In this one image, we go from an asteroid in our own solar system, to a star in our own galaxy (complete with diffspikes)



To a nearby galaxy (redshift 0.019), and one not so nearby (z=0.084) with an active nucleus (probably a starburst, rather than an AGN)




To a rich cluster far in the background (z=0.371):



To a mystery:



Thanks to zooite 1001G for posting this in Radio Galaxy Zoo Talk, 1 RADIO SOURCE GALAXY & SPIRAL GALAXIES.

The red contour lines are from a FITS I downloaded from SkyView, using the VLA FIRST (1.4 GHz) survey, and which I processed using Python (some details in the RGZ Talk thread How to decide the 'zero point' for radio contours?).

The mystery? The apparent source of the strong radio emission seen by FIRST is SDSS J103250.26+155116.8, which SDSS thinks is a STAR. As we have learned, over in Radio Galaxy Zoo, these often turn out to be quasars, far in the background (z>~1.5). In this case, the mystery isn't just whether that 'star' is, in fact, the source of the radio emission; it's also what sort of emission it is! Is it #corejet? Or a #wat? Or something else?

What mysterious objects can you find, among the Radio Galaxy Zoo images?

minor note: the scale bar is ~1.5% too small (not that you could tell)

3
Cafe at the end of the Universe / Fireflies (and lighting bugs)
« on: June 27, 2014, 01:10:59 am »
Nothing to do with astronomy, so I'm starting this thread in the Cafe at the end of the Universe.

The fireflies (or lightning bugs) are out tonight. Always worth some quiet time to sit and watch them. Here, they're yellow.

Do you have fireflies where you live? Is this the time of year/day when they're most active? Do you have fireflies which glow green? orange? red? (or just yellow?)

Nothing to do with astronomy Maybe not  :P The SDSS telescope is at Apache Point, New Mexico. Do they have fireflies too? Do any fireflies fly high enough (and are out late enough) to show up in an SDSS image? Might some #satellitetrails actually be local fireflies?

4
Hot off the arxiv press: A Catalogue of Two-Dimensional Photometric Decompositions in the SDSS-DR7 Spectroscopic Main Galaxy Sample: Preferred Models and Systematics, by Alan Meert, Vinu Vikram, and Mariangela Bernardi (arXiv:1406.4179):

Quote from: Meert+
We present a catalogue of two-dimensional, PSF-corrected de Vacouleurs, Sersic, de Vacouleurs+Exponential, and Sersic+Exponential fits of ~7×105 spectroscopically selected galaxies drawn from the SDSS DR7. Fits are performed for the SDSS r band utilizing the fitting routine GALFT and analysis pipeline PyMorph. We compare these fits to prior catalogues. Fits are analysed using a physically motivated flagging system. The flags suggest that more than 90 percent of two-component fits can be used for analysis. We show that the fits follow the expected behaviour for early and late galaxy types. The catalogues provide a robust set of structural and photometric parameters for future galaxy studies. We show that some biases remain in the measurements, eg. the presence of bars significantly affect the bulge measurements although the bulge ellipticity may be used to separate barred and non-barred galaxies, and about fifteen percent of bulges of two-component fits are also affected by resolution. The catalogues are available in electronic format. We also provide an interface for generating postage stamps images of the 2D model and residual as well as the 1D profile. These images can be generated for a user-uploaded list of galaxies on demand.

 8)

5
You may remember that in 2013 three ordinary zooites were invited to attend the annual Zooniverse team meeting; see Zooniverse blogs Calling all Zooites! Your chance to attend the second Zooniverse Project Workshop in Chicago! (February 27, 2013), and Project Workshop Winners (March 13, 2013), also this forum's Would you like to go to Chicago? Zooniverse Project Workshop and Second Zooniverse Project Workshop: 29 and 30 April 2013 threads.

This year the only announcements are two Daily Zooniverse posts, Zoo Tattoo (May 19, 2014) and Meet the “entire” Zooniverse Team (May 20, 2014)1. Here's the latter:

Quote
Hey all, we took this picture today during our annual Zooniverse team meeting at the Adler Planetarium in Chicago. It was pretty hot and humid out there, which made me really regret being in a suit! The only people missing in this shot are Kelly Borden and Chris Lintott who sadly had to leave early.

We’ve been in Chicago (where half of the team are based) since Monday discussing how to move forward with the Zooniverse and make taking part in our projects an even better experience for everyone involved :)

Here's the image:



Can you put names to all the 22 faces?

1 It has been pointed out to me that there are also some Tweets (on Twitter); I don't do Twitter

6
by Ivezic, Connolly, VanderPlas and Gray (2014, Princeton Univ. Press, ISBN 978-0-691-15168-7).

My aim in starting this thread is to have a single place where those interested in this book+1 can share their:
  • experiences going through it
  • learning using it
  • comments on it
  • suggestions for further reading or learning
  • etc.

JohnF introduced GZ zooites to it, here in this forum: Review of "Statistics, Data Mining and Machine Learning in Astronomy":

Just read a review of "Statistics, Data Mining and Machine Learning in Astronomy" (In "Journal of the British Astronomical Association", April 2014).  In it, the reviewer believes that data mining (of internet data) is a "Step up, from the Galaxy Zoo type of project".  Another quote - "Hanny's Voorwerp is a prime example of a truly significant amateur discovery made in the Galaxy Zoo project".

The review mentions SDSS and also a big software project - AstroML (http://www.astroml.org), on which the book is based.  The different software which the book mentions, is free to download.

It is also briefly discussed in Quench Talk, starting with a post by mlpeck (it's towards the bottom of p1 of the Clean "021020" galaxies: 11 April catalogs, comparisons, and discussion thread):

Quote from: mlpeck
I do have one recommendation, perhaps for JeanTate but certainly for any working scientists who wander by: get the recently published book Statistics, Data Mining, and Machine Learning in Astronomy by Ivezic, Connolly, VanderPlas and Gray (2014, Princeton Univ. Press, ISBN 978-0-691-15168-7).

Calculus and some basic matrix algebra are prerequisites to understand the text, so it's probably not for the average zoo-ite. I would guess that most working scientists would find something to learn from the book even if they are experts in some aspect of data analysis just because the authors cover a huge amount of ground (mostly superficially to be sure).

Another thing that's useful about the book for astronomers is they make use of non-toy astronomical datasets from SDSS and other large surveys. Every chapter has some discussion of robust methods and methods for outlier detection in large datasets, and some of their ideas are certainly applicable to this project.

Right now I am skipping my way through the text. When I have access to more computing resources than the laptop and tablet I have with me at the moment I plan to dig into some of their data and algorithms. Techniques for cross-validation are pretty new to me, and I have some data I want to try out some ideas on.

The book uses Python code throughout, but its introduction to the language is too brief to be really useful. So, for the non Python programmer another resource is needed to learn Python. Something else fun to do!

On p4 of that same Quench Talk thread, Science Team member Kyle Willett wrote:

Quote from: KWillett

Also, a books recommendation (and I'm delighted that we're using more advanced stats/tools): I think the Ivezic et al. book is particularly good, and it comes with a built-in website with many of the tools that you can try out. Python is also my primary tool for data analysis these days. http://www.astroml.org/index.html

If you're looking for a particular book (and I know academic books are expensive), many library systems should have it. I don't know the specifics of where all of you live, but in Minnesota (for example) anyone can request books from the University library, such as these, via ILL for free. Might be worth a try.

I now have a Kindle version of this book (my 'rainy day jar of quarters' is no more  :() - yes, the Amazon Cloud Reader does work - on my Linux box (where I do 'my Python work'), and have started to read it.

Looking forward to fun and challenges; hope you'll join in!  :)

1 It's much more than just a book ...

7
Over the years, the Galaxy Zoo blog has featured posts like Congratulations Edmond: another Galaxy Zoo paper accepted, Galaxy Zoo and undergraduate research: spiral arms, colors, and brightnesses, and First Result from Galaxy Zoo Hubble (this is just a small selection, from just the last six months or so).

From these posts, and the not-just-a-few like them, we get a blurry picture of what's going on behind the scenes, so to speak.

We learn, for example, that "Zach [Pace] worked at the University of Minnesota during the summer of 2013 through the NSF’s Research Experience for Undergraduates (REU) program. Zach is continuing to work with Galaxy Zoo data as part of his senior thesis"; that Becky Smethurst  is "the latest addition to the Galaxy Zoo team as a graduate student at the University of Oxford"; that "over 100 scientific research papers [have been] published which make use of your classifications, some of which have been written by the select few Galaxy Zoo PhD students (most of us are also previous Zooites)", that Tom Melvin is (or was) "a 3rd year PhD student at Portsmouth University [...] part of the Galaxy Zoo team for over two years now", that "new Galaxy Zoo science team member Edmond Cheung, [is (or was)] a PhD student from UC Santa Cruz", ...

Backreaction is a blog written (mostly) by theoretical physicist Sabine Hossenfelder (a.k.a. "Bee"). One of her recent posts is Academia isn’t what I expected; here's a paragraph I was particularly struck by:

Quote from: Bee
My biggest reality shock was how much of research has turned into manufacturing, into the production of PhDs and papers, papers that are necessary for the next grant, which is necessary to pay the next students, who will write the next papers, iterate. This unromantic hamster wheel still shocks me. It has its good side too though: The standardization of research procedures limits the risks of the individual. If you know how to play along, and are willing to, you have good chances that you can stay. The disadvantage is though that this can force students and postdocs to work on topics they are not actually interested in, and that turns off many bright and creative people.

Maybe this "unromantic hamster wheel" partly explains why we rarely see posts from astronomers - in this forum or GZ Talk (etc) - any more? In fighting for the next grant/PhD student, the Science Team members (academics all?) can't win funds to pay for time spent posting (You want $$ to spend time hanging out on internet fora? Are you nuts?), and can't afford to take time to post (Finish off a grant proposal, or hang out in the GZ forum? That's not a choice!).

This also may be partly why Grant Miller, the Zooniverse Community Manager seems to have no time to engage in public discussions with that community (or at least the GZ part of it) ... it's not a grant/paper/PhD student productive use of his time. Also why there seems to be money for new Zooniverse projects (yay!), but none to fix Talk, or Letters, or launch a Zooniverse forum, or ... money and time spent on any of these would be money and time that would not be spent on more PhD students, analyzing zooites' clicks and writing papers, etc.

For at least the kind of citizen science that is GZ, applying the manufacturing analogy leads to this: just as humans have been, and are continuing to be, replaced by robots in factories, so too zooites will be replaced by machine learning software (as is all-but explicit in the Zooniverse blog post Wrap-Up from the Workshop on Citizen Science in Astronomy).

But just as the 'edge' successful manufacturers seek comes from the most un-robot-like creativity of humans, and as many bright and creative people are turned off by the unromantic hamster wheel, perhaps GZ should find ways to harness the creativity etc of zooites (and stop trying to turn them into mindless classifiers)?

What do you think?

8
We Galaxy Zoo zooites have threads, here in the forum, for many different kinds of galaxy - barred, merging, ellipticals (and many more) - catalogs (e.g. Kiso Ultraviolet Galaxy Catalogue, NGC Catalogue, Flat Galaxy Catalogue), nebulae (e.g. The Nebulae Collection (formed from many threads)), comets, asteroids, Hubble stars, conjunctions of stars and galaxies, faces, oddballs, .... *



That's the DR7 image of SDSS J013308.42-000412.3; yes, it's a nice galaxy/star conjunction, and the star itself is rather cool, but I think one of the most spectacular aspects is the 'compass points', the four diffraction spikes. Or 'diffspikes', as I call them. Given our extreme enthusiasm for making collections, I was slightly surprised to discover that there is no specific thread devoted to diffspikes!  :P At least, none that I could find. Of course, there's a very long thread which has many excellent images of SDSS diffspikes, The best Stars!, and all of the diffspike images in today's OotD come from that thread^ (unless otherwise noted).

What are diffspikes?

Almost all reflecting telescope designs have something in front of the main mirror, an obstruction. For the main 2.5m SDSS telescope, that obstruction is the 1.08m secondary mirror:



That secondary mirror needs to be supported; its support is four 'spiders', vanes which extend from the main (exterior) trusses to the secondary mirror and its support structures. This main SDSS telescope has an altitude-azimuth mount, and the spiders are at ~45° to the horizontal. You can just make these spiders out in this image:



And in this image, you can see more clearly just how much hardware there is, 'inside' the telescope (not just the secondary mirror and its spiders!) (source):



Enough about telescopes, more diffspikes!



SDSS J095206.32+540343.6, SDSS J021856.66+283822.7, and SDSS J124420.22-084017.0 (the last one is a repeat of SDSS J013308.42-000412.3).

Although the spiders are fixed, and as the telescope has an alt-azimuth mount, the angle the diffspikes make with North (up in all images; East to the left) is not always ~45°. As is clear in these four images.



SDSS J023605.49+065321.3, posted by AlexandredOr, with the caption "A star reflected in a broken mirror". There seems to be at least two sets of diffspikes here, can you work out why?



That's SDSS J132107.00+471631.2, posted by EricFDiaz, as the only post in the Old Red thread. He wrote, "Look at the diffraction spikes on this baby. You can see spectral colors in the spikes."

Spectral colors? As far as I could find, this is the only reference, here in the GZ forum, to diffspikes having "spectral colors", or similar (if you come across any others, please let me know!). Once it's pointed out to you, you'll see these spectral colors in many, perhaps most, SDSS images of diffspikes.

And indeed, diffspikes are low grade spectra; do you think it's possible to analyze the data in the five FITS files that are the digital record of the five SDSS images (one for each band, u, g, r, i, and z), and produce a spectrum?

If you're interested in learning more about the optics, how obstructions cause diffspikes (and more), etc, I found this Beugungsbild.de webpage (by René Pascal, "... Aesthetics and Physics of Imaging Methods") very well-written and easy to follow (it also has cool images): Diffraction Pattern of Obstructed Optical Systems. And DuckDuckGo (a cool search engine) will find you lots of good sites which explain the physics of diffspikes in as little, or as much, detail as you'd like.

* A Classifier's Guide To The Objects Topics (Or Where To Post That Great Galaxy) is a great resource for finding many of these thread, but not all of them
^ the ones I used were posted by Hofi (0133-0004), elizabeth (0952+5403), Mjtbarrett (02182838), and Mukund Vedapudi (1244-0840).

9
May not be the best place to post this, but I think it's really cool that this job opening has been created!  :) 8)

Quote
As part of the increased involvement in the Zooniverse at the University of Portsmouth, we are offering a two-year research position to work closely with the main Zooinverse development team and help foster local Zooniverse projects within Portsmouth and beyond. This new position is part of the official buy-in of Portsmouth into the Citizen Science Alliance and builds on past and present Zooniverse interest at the university.

More details in yesterday's Zooinverse blog entry, Zooniverse job at the University of Portsmouth.

10
Object of the Day / Tuesday, 22 April, 2014: Star? Galaxy? Both!
« on: April 22, 2014, 12:38:30 am »


"Sometimes I find beautiful pictures with astonishing conjunctions galaxy and star. It's just for esthetic reasons that I propose to collect them here..."

So begins the first post, by AlexandredOr, in a very long thread, Conjunctions galaxy/star.

These galaxy-star conjunctions are of many different kinds; for example:







Sometimes such a conjunction causes confusion, not only for zooites, but even for the SDSS imaging software pipeline; like this:



And sometimes even a spectrum doesn't really help clear up the confusion!  ;D



Fortunately, there are two spectra for of this conjunction: 725253573776009216, which is a "starforming galaxy"; and 725251924911220736, an "M3 star". Now imagine there was just one; how would it have helped?




Do you have favorite star-galaxy conjunction?


While many objects were posted as DR7, AHZ, DR8, etc images, all in this post are DR9. From top to bottom they are:

* might be more visually striking in the original, AHZ5000eme:


** in the DR8/AGS original image the star is much less obvious, AGS00000hm:

11
Star space / Good books on statistics in astronomy?
« on: April 21, 2014, 08:55:38 pm »
Recommendations from anyone reading this? Preferably based on direct exposure/experience!  ;D

Some background (source):
Quote from: mlpeck
I do have one recommendation, perhaps for JeanTate but certainly for any working scientists who wander by: get the recently published book Statistics, Data Mining, and Machine Learning in Astronomy by Ivezic, Connolly, VanderPlas and Gray (2014, Princeton Univ. Press, ISBN 978-0-691-15168-7).

Calculus and some basic matrix algebra are prerequisites to understand the text, so it's probably not for the average zoo-ite. I would guess that most working scientists would find something to learn from the book even if they are experts in some aspect of data analysis just because the authors cover a huge amount of ground (mostly superficially to be sure).

Another thing that's useful about the book for astronomers is they make use of non-toy astronomical datasets from SDSS and other large surveys. Every chapter has some discussion of robust methods and methods for outlier detection in large datasets, and some of their ideas are certainly applicable to this project.

Right now I am skipping my way through the text. When I have access to more computing resources than the laptop and tablet I have with me at the moment I plan to dig into some of their data and algorithms. Techniques for cross-validation are pretty new to me, and I have some data I want to try out some ideas on.

The book uses Python code throughout, but its introduction to the language is too brief to be really useful. So, for the non Python programmer another resource is needed to learn Python. Something else fun to do!


Quote from: Jean Tate
Cool! :)

Over the last few weeks I've been looking for books of this kind, and had found Modern Statistical Methods for Astronomy: With R Applications by Feigelson and Babu (2014, Cambridge University Press, ISBN 978-0-521-76727-9), and Statistical Data Analysis, by Cowan (1998, Oxford University Press, ISBN 978-0-198-50156-5). Are you - or any other reader - familiar with either? Would you recommend either? If your budget can stretch to just one, which would you recommend?

12
Many papers are based on values for several key parameters derived from MPA-JHU data products. These include various line fluxes (and their errors), the 4000 Å break strength ("D4000", and its error), velocity dispersion ("V_DISP", and its error), and the star-formation rate ("SFR").

The methods used to produce these estimates are described in a number of papers, principally Brinchmann+ 2004, Kauffmann+ 2003, and Tremonti+2004 (see above link for details).

I have downloaded and read each of these, looking specifically to understand how the data products address:

 - spectra contaminated by overlapping/foreground galactic stars (including the diffraction spikes - diffspikes - from very bright stars, which may be several arcmins from the galaxy)

 - spectra contaminated by overlapping - either foreground or background - galaxies, whether at similar or quite different redshifts

 - SDSS spectra with some regions masked out (these regions may be as small as a few pixels, or as large as ~1000+ Å)

 - SDSS spectra whose redshift estimate carries the warning "SMALL_DELTA_CHI2".

I found nothing; no mention in any of the papers of any of these. Although none seem to come out and say it openly, they all seem to very firmly assume that each and every spectrum they let their pipeline(s) loose on is 'good' (no masked regions, no poorly subtracted sky lines, etc) and is of a single system of gravitationally bound stars, gas, dust, and perhaps an AGN.

Yet there are hundreds of objects in the Quench project, and very likely tens of thousands in the full MPA-JHU catalog, which have either 'bad' spectra, spectra containing more than one redshift system, or both!  :P

How do astronomers decide which among these many hundred should be excluded from analyses which use the values of the MPA-JHU parameters.

Specifically, how can such decisions be made in an objective, quantitative, reproducible, scientifically-acceptable manner?

13
Consider AGS00001c9 (SDSS J152907.25+302944.5; DR7 ObjId 587736942525415485), seen here in DR9:



A diffraction spike from (of?) the neighboring bright star crosses the galaxy. If a non-BOSS* spectrum had been taken at the same time (it wasn't), it would have captured light from the star ... as can be seen here (the 3" fiber aperture would touch the inner ends of the cross-hairs):



As I understand it, in general the orientation - on the sky - of diffraction spikes depends on the type of telescope mount, and the altitude and azimuth of where it's pointed, at the time an image/spectrum is taken. So, in general, if an image and a spectrum of an object close to a bright star are taken at (very) different times, they won't both be diffspiked.

But is that true of SDSS images and spectra?

* BOSS spectra have 2" diameter fibers

14
... the DR9 galSpecLine ("Emission line measurements (from MPA-JHU spectroscopic re-analysis) for this spectrum") says they're both in emission?  ???

I have come across many examples, in the Quench project, among both the Quench sample (QS) and control (QC) objects.

Here's a particularly obvious one, a QS object, AGS00001xa, SDSS J114159.39+265700.0 (DR7 ObjId 587741601491517466, SpecObjID 2500685054489946112):

DR9 image:



And two screen-shots from the interactive spectrum (the red line is "Best Fit"):





The halpha_flux is given as 65.1764±8.19592, and the hbeta_flux as 0.063206±6.038076. Yes, "Warnings: MANY_OUTLIERS"; however, there are plenty of examples without such a warning.

15
Object of the Day / Friday, 21 February, 2014: Very Strange Spirals?
« on: February 21, 2014, 03:12:33 pm »


No, that's not a strange spiral!  :P That's M87, perhaps the most famous giant-elliptical-with-an-active-SMBH-and-jet; you can see the jet in the optical in this DR10 SDSS image (it's the small white streak at ~2 o'clock).

If we change the scale in a bit, and switch to the radio part of the spectrum, the jet is much more obvious, and we can also see huge clouds of plasma (hot, ionized gas), called lobes ... and the stars have disappeared (source, data is from the Very Large Array radio telescope):



Radio jets and lobes and giant elliptical galaxies are common companions; the super-massive black holes (SMBHs) associated with AGNs (active galactic nuclei) in elliptical galaxies somehow seem to often produce one or two radio jets and/or radio tails and/or lobes1.



The galaxy in the center is, obviously, not an elliptical. It is also - obviously - associated with a pair of radio jets/lobes. This galaxy is called 0313-192  ::) and is the subject of a 2006 paper by W. Keel, R. White, F. Owen, and M. Ledlow2 (you might recognize the first author ... he's none other than our very own zooite, NGC3314!).

Since 2006, a small number of papers have reported similar spiral/radio jet/lobe associations; unfortunately, all the objects seem to be like 0313-192, outside the SDSS footprint!  :(

So, there are (tens of? hundreds of??) thousands of ellipticals-with-jets/lobes, but just a tiny handful of spirals-with-jets/lobes, maybe only three. Or, as raynorris (scientist) said, on December 19 2013, over in Radio Galaxy Zoo (RGZ) Talk:

Quote
Keep an eye out for any #hourglass sources that seem to be hosted by galaxies that look spiral in the infrared. These objects are incredibly rare in the local Universe (only 2 or 3 known) and we may not see any in Radio Galaxy Zoo, but if someone does find one, that would be worth writing a paper about (with the discoverer as co-author, of course). The rarity of radio-loud spirals is thought to be because the radio jets heat up and disrupt the gas in the spiral, switching off star formation, and turning the galaxy into a "red dead" elliptical. But we might find one or two where the jets have only just switched on and haven't yet destroyed the spiral.









That is a compilation of SDSS DR10 images of galaxies which seem to be associated with jets/lobes, found by RGZ zooites; respectively (click the links for details): infobservador (ARG0002zck, SDSS J154336.07+110512.9), WizardHowl (ARG0001zj8, SDSS J122640.22+253855.5), infobservador (ARG0002esa, SDSS J140535.56+190612.9), and WizardHowl3 (ARG00022wh, SDSS J112811.63+241746.9). It's not complete - there are certainly others which have been reported by zooites, in RGZ - but they're the only ones I could find after an hour or two's searching4 (and which are more than a spiral associated with radio emission only in/from the nucleus/bulge).

Can you find spirals with jets or lobes, 'hourglass' or 'doublelobe' radio sources? Come along to RGZ and start classifying!  ;D

1 for more on this topic check out the GZ blog posts Tailed Radio Galaxies: Cometary-Shaped Radio Sources in Clusters of Galaxies (Part 1), More Information on Tailed Radio Galaxies (Part 2), How do black holes form jets?, The Curious Lives Of Radio Galaxies – Part One, and The Curious Lives of Radio Galaxies – Part Two (there are more, this is just a 'starter selection')

2 The image is from Hubblesite, "Credit: NASA, W. Keel (University of Alabama), M. Ledlow (Gemini Observatory), F. Owen (NRAO) and AUI/NSF"

3 Unfortunately, I don't seem to be able to make composite SDSS/radio images  :'(

3 Talk's search tool has got to be one of the primitive, inflexible, tiresome search tools ever invented!  >:(

ETA: I've added some names to the RGZ candidates, to more easily keep track of them

Pages: [1] 2 3 ... 19