Author Topic: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't  (Read 9181 times)

JeanTate

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This SDSS image appeared in the Wanted galaxies pair!One blue,red the other one. thread (here in the GZ forum), stardate November 20, 2008, 05:18:25 am, posted by sayonave08:



Other than the pair of IDs ("id=587731870169301121,id=587733081347063839"), sayonave08 wrote nothing.

A few minutes later, at 05:32:14 am, sayonave08 posted something a bit meatier, in the Quasi-Stellar radio sources. Find a Quasar? Post it here! thread:

QSO z=0.008,id=587733081347063838,My best friend,Galaxy Part of UGCA 239,id=587733081347063839


Later that same day (at 11:24:48 am), dthomas02 responded:

QSO z=0.008,id=587733081347063838,My best friend,Galaxy Part of UGCA 239,id=587733081347063839

Hi sayonave08. You might want to recheck this one. It doesn't much look like one and the z is 0.0085 with a high confidence - the nearest recorded to date is 3C273 which is at z=0.158

Fast forward a bit over five years, to January 28 2014 11:52 AM, and SCIENTIST KWillett wrote, in the A new transient discovered in SDSS data thread in GZ Talk:

Quote from: KWillett
M. Koss and collaborators (including GZ science team member Kevin Schawinski) have just submitted a new paper on a transient object discovered in a nearby dwarf galaxy. Originally thought to be either a supernova or a QSO, they suggest that it is a luminous blue variable (LBV) star that has been erupting for decades, since at least 1950, and then FOLLOWED by a supernova in 2001.

http://arxiv.org/abs/1401.6798v1

A very interesting object, and one that was discussed by GZ volunteers back on the forum in 2011.

http://www.galaxyzooforum.org/index.php?topic=279576.msg569089#msg569089

Later that same day (04:47:33 pm), he wrote a post in the Wednesday, 2nd November, 2011: A Pretty Galaxy Group OOTD, quoting a long post by c_cld from earlier in that thread, dated November 16, 2011, 06:25:42 pm, and added: "A new paper on this precise object has been submitted to MNRAS. They suggest that it's in fact a luminous blue variable (LBV) star erupting over decades, followed by a supernova explosion in 2001. http://arxiv.org/pdf/1401.6798v1.pdf"

The paper by M. Koss and collaborators (including GZ science team member Kevin Schawinski) is titled "SDSS1133: An Unusually Persistent Transient in a Nearby Dwarf Galaxy"; here's the abstract:

Quote from: Koss+ 2014
We have discovered an unusual source offset by 0.8 kpc from a nearby dwarf galaxy while performing a survey to detect recoiling black holes. The object, SDSS J113323.97+550415.8, exhibits broad emission lines and strong variability. While originally classified as a supernova (SN) because of its nondetection in 2005, we detect it in recent and past observations over 63 yr. Using high-resolution adaptive optics observations, we constrain the source emission region to be <12 pc and find a disturbed host morphology indicative of recent merger activity. Observations taken over more than a decade show narrow [O III], constant ultraviolet emission, broad Balmer lines, a constant putative black hole mass over a decade of observations despite changes in the continuum, and optical emission-line diagnostics consistent with an active galactic nucleus (AGN). However, the optical spectra show blueshifted absorption, and eventually narrow Fe II and [Ca II] emission, each of which is rarely found in AGN spectra. While this peculiar source displays many of the observational properties expected of a potential black hole recoil candidate, most of the properties could also be explained by a luminous blue variable star (LBV) erupting for decades since 1950, followed by a Type IIn SN in 2001. Interpreted as an LBV followed by a SN analogous to SN 2009ip, the multi-decade LBV eruptions would be the longest ever observed, and the broad Halpha emission would be the most luminous ever observed at late times (>10 yr), larger than that of unusually luminous supernovae such as SN 1988Z, suggesting one of the most extreme episodes of pre-SN mass loss ever discovered.

Koss et al. recount the history of "SDSS J113323.97+550415.8 (hereafter SDSS1133)" in their introduction:

Quote
SDSS1133 was mentioned as a possible case of a quasar having a noncosmological redshift because of its broad Balmer lines but very low luminosity (Lopez-Corredoira & Gutierrez 2005). In a study of narrow-line Seyfert 1 galaxies, Zhou et al. (2006) classified SDSS1133 as a SN because of its nondetection in data obtained in January 2005 with the 2.16 m telescope at the Beijing Observatory. Finally, SDSS1133 was listed as a possible “Voorwerp” candidate for a giant ionized cloud (Keel et al. 2012).

Hmm, "Voorwerp" candidate, Keel, ... sounds like it was mentioned - possibly even discussed - here in the GZ forum too. Time to dig a bit ...

In the Wanted! Galaxy pairs which overlap but are not merging thread, on February 11, 2010, 04:47:37 pm, c_cld wrote:

587733081347063839 z=0.0078 , SDSS J113323.47+550420.6  SpecObjID = 285923593806675968
in front of
QSO 587733081347063838 z=0.0085 , SDSS J113323.97+550415.8 SpecObjID = 285642003167838208



awesome..

Not exactly voorwerpje, so how did the "possible “Voorwerp” candidate" come about?

Well, Table 1 of Keel et al. 20121 - "Candidate AGN with extended emission-line clouds" - includes SDSS J113323.97+550415.8 (DR7 ObjId 587733081347063838), with a "Sy 1" nucleus (Seyfert type 1), "Mkn 177 compn" note (companion to Markarian 177?), "S" as search type ("serendipitous") and "stellar190" as posted by. And here's stellar190's post (dated August 31, 2009, 01:39:19 pm), the OP of the Whats going on here? thread:

I'm confused with this one, i thought at first a star forming region or a star, but the z for the galaxy and the blob are the same ( 0.008 ) and the spectra doesnt look right for a star forming region ??? Its looks to be active?



http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587733081347063838

Posted before by sayonave08 in the QSO thread

And so it goes ... the bright blue star-like object - named SDSS1133 by Koss et al. - and/or the dwarf galaxy Mkn 177/UGCA 239 was posted here in the GZ forum many, many times. By quite a few different zooties. Some of whom were not aware of who had posted it earlier, or why. Etc, etc, etc.

It certainly is a very unusual object2, at least as unusual as Hanny's Voorwerp, Bruno's Mystery Violin Clef, and mitch's Mystery Star.

SDSS1133, the giant fish that got away Galaxy Zoo discovery that wasn't.  ;)   :P :(

1 "The Galaxy Zoo survey for giant AGN-ionized clouds: past and present black hole accretion events" is the title, and the authors are William C. Keel, S. Drew Chojnowski, Vardha N. Bennert, Kevin Schawinski, Chris J. Lintott, Stuart Lynn, Anna Pancoast, Chelsea Harris, A.M. Nierenberg, Alessandro Sonnenfeld, & Richard Proctor. You can get a copy of this from the Zooniverse Published Papers page, or by clicking this link

2 Koss+ write "A survey of all [...] found only two objects offset from the host-galaxy nucleus: SDSS1133 along with a very close dual AGN Mrk 739 (Koss et al. 2011)." I wonder whether the "very close dual AGN Mrk 739" has been posted here before, by zooites who noted it as unusual?

c_cld

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #1 on: February 06, 2014, 05:19:23 pm »

2 Koss+ write "A survey of all [...] found only two objects offset from the host-galaxy nucleus: SDSS1133 along with a very close dual AGN Mrk 739 (Koss et al. 2011)." I wonder whether the "very close dual AGN Mrk 739" has been posted here before, by zooites who noted it as unusual?

Answer given by search of 587742013279502422: 20 posts along with OOTD!  8)

zutopian

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #2 on: February 06, 2014, 05:32:59 pm »

2 Koss+ write "A survey of all [...] found only two objects offset from the host-galaxy nucleus: SDSS1133 along with a very close dual AGN Mrk 739 (Koss et al. 2011)." I wonder whether the "very close dual AGN Mrk 739" has been posted here before, by zooites who noted it as unusual?

Answer given by search of 587742013279502422: 20 posts along with OOTD!  8)

The Dual AGN Mrk 739 is one of the confirmed voorwerpje!

zutopian

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #3 on: February 07, 2014, 08:48:02 pm »
SDSS1133 was presented together with other galaxies in a previous "Object of the Day".:
http://www.galaxyzooforum.org/index.php?topic=279849.msg579564#msg579564

JeanTate

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #4 on: February 07, 2014, 10:36:06 pm »
The Green Peas (GP) Galaxy Zoo serendipitous discovery is different from Hanny's Voorwerp, Bruno's Mystery Violin Clef, and mitch's Mystery Star in several ways; for example, it is about a class of objects (not just a single one); it involved spontaneously organized, independent research by ordinary zooites; and that research went beyond the triggering JPG/PNG SDSS images.

We can't change history, but we can look into how we - ordinary zooites, collectively - might have worked out that SDSS1133 was rather more peculiar than its purported 'Sy1' designation.

Start with variability.

Via NASA's SkyView1, it's pretty straight-forward to get five JPG images of Mkn 177 from the DSS (Digitized Sky Survey); for example, here it is from DSS2 IR:



By downloading the FITS files, and using a FITS tool such as DS9, we could very likely have concluded that SDSS1133 was quite a lot brighter at the time it was imaged by SDSS than it was when imaged by DSS. And doing quantitative analyses and literature searches of about the same level of difficulty as some of those done in the GP project, we could have concluded that SDSS1133 showed extreme variability, for an Sy1 object2.

Post-HV3, maybe a Galaxy Zoo serendipitous discovery needs to be more GP-like, if it is to get the attention of professional astronomers? Maybe "What's this strange thing? - Anyone?" is no longer enough?

What do you think?

1 and, very likely, several other easy-to-use websites
2 and this is precisely what Koss+ 2014 did, albeit more rigorously than we'd have been able to, and using data we could not possibly have had access to (e.g. PS1)
3 Hanny's Voorwerp

Tony Wei

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #5 on: February 08, 2014, 08:42:15 am »
Can we assume that it's a LBV in a nearby ultra-faint galaxy like Leo IV*?
And, I digged out a large sum of images**:
      DSS1
      DSS2
      GALEX
     SDSS DR4
     DR5
     DR6
      DR7
      DR8
      DR9
      DR10
      2MASS J
      H
      K
      WISE band1
      2
      3
      4
      Multi-color
*http://hubblesite.org/gallery/album/entire/pr2012026g/
**There's something wrong with my browser,so I'll try to get DR1-3 images later.
« Last Edit: February 10, 2014, 08:01:07 am by Tony Wei »
Our greatest glory is not in never falling ,but in rising every time we fall.
——Nelson Rolihlahla Mandela

JeanTate

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #6 on: February 09, 2014, 04:06:35 pm »
Nice post, Tony Wei!  :)

One thing which you can sorta see in these images: SDSS1133 is blue, and is brightest in the SDSS images1. For all but the DSS images, the source data used to create the images is digital: binary data streams from A/D converters in cameras. The DSS sources are 'plates', glass coated with photographic emulsions, 'exposed' and 'developed'; these were converted to digital form - up to decades after the actual observations - by automatic scanning machines that are a bit like microscopes.

Quote
Can we assume that it's a LBV in a nearby ultra-faint galaxy like Leo IV*?

Mrk 177 is 'nearby' in that it's 'only' ~29 Mpc distant; Leo IV is much closer, being within the Local Group and is likely a satellite galaxy to our own Milky Way. If SDSS1133 had been in Leo IV, its variability would have been discovered decades ago ... any reader care to make an estimate of how bright it would appear, in SDSS, if it were only 160 kpc distant?

In terms of brightness, Koss+ 2014 write "Given the observed magnitude of g = 15.69 (SDSS), the galaxy absolute magnitude is Mg = -16.6, comparable to the Small Magellanic Cloud"; the morphology, however, is more like that of M32.

1 And that it's pretty much the same in all SDSS images ... which is what you expect, because the different images differ only in how the raw data ("the observation") was processed; there is only one SDSS observation (set of five-band 'CCD-readouts') of SDSS1133 (if it had been in Stripe 82, there would have been many more ...)

planetaryscience

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #7 on: February 09, 2014, 04:22:57 pm »
absolute magnitude=brightness at 10 parsecs.

160000/10=16,000 times further

The object would be around magnitude -12, enough to cast shadows at night.  8)
I like to find asteroids and galaxy mergers- but all galaxies are still fine to me.

c_cld

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #8 on: February 09, 2014, 05:00:22 pm »
....
1 And that it's pretty much the same in all SDSS images ... which is what you expect, because the different images differ only in how the raw data ("the observation") was processed; there is only one SDSS observation (set of five-band 'CCD-readouts') of SDSS1133 (if it had been in Stripe 82, there would have been many more ...)

Actually two SDSS "observations" in two raw data runs, 104 days apart:

http://data.sdss3.org/fields/runCamcolField?run=2821&camcol=5&field=158 on mjd 52261
http://data.sdss3.org/fields/runCamcolField?run=3103&camcol=5&field=112 on mjd 52365

 ;)

JeanTate

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #9 on: February 09, 2014, 05:56:00 pm »
....
1 And that it's pretty much the same in all SDSS images ... which is what you expect, because the different images differ only in how the raw data ("the observation") was processed; there is only one SDSS observation (set of five-band 'CCD-readouts') of SDSS1133 (if it had been in Stripe 82, there would have been many more ...)

Actually two SDSS "observations" in two raw data runs, 104 days apart:

http://data.sdss3.org/fields/runCamcolField?run=2821&camcol=5&field=158 on mjd 52261
http://data.sdss3.org/fields/runCamcolField?run=3103&camcol=5&field=112 on mjd 52365

 ;)

Yes, right ... it's mentioned in Koss+ 2014 (two SDSS datapoints in the 'lightcurve', for example).

Oops!  :-[

JeanTate

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #10 on: February 09, 2014, 05:58:02 pm »
absolute magnitude=brightness at 10 parsecs.

160000/10=16,000 times further

The object would be around magnitude -12, enough to cast shadows at night.  8)

Am not sure I follow you here, planetaryscience; would you care to show your working (the steps in your calculations), in more detail?

planetaryscience

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #11 on: February 09, 2014, 06:12:38 pm »
absolute magnitude=brightness if object is 10 parsecs away
absolute magnitude=-16.6


160 kiloparsecs=160,000 parsecs

how many times further is 160,000 than 10?

160,000/10=16,000

The object is 16,000 times further than if it was 10 parsecs away.

the object is 16,000 times dimmer, then.

16,000=about 4 and a bit orders of magnitude.

-16.6+4 and a bit=~-12.

Does that seem realistic?  ???
I like to find asteroids and galaxy mergers- but all galaxies are still fine to me.

Tony Wei

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #12 on: February 10, 2014, 08:24:38 am »
Nice post, Tony Wei!  :)

One thing which you can sorta see in these images: SDSS1133 is blue, and is brightest in the SDSS images1. For all but the DSS images, the source data used to create the images is digital: binary data streams from A/D converters in cameras. The DSS sources are 'plates', glass coated with photographic emulsions, 'exposed' and 'developed'; these were converted to digital form - up to decades after the actual observations - by automatic scanning machines that are a bit like microscopes.

Quote
Can we assume that it's a LBV in a nearby ultra-faint galaxy like Leo IV*?

Mrk 177 is 'nearby' in that it's 'only' ~29 Mpc distant; Leo IV is much closer, being within the Local Group and is likely a satellite galaxy to our own Milky Way. If SDSS1133 had been in Leo IV, its variability would have been discovered decades ago ... any reader care to make an estimate of how bright it would appear, in SDSS, if it were only 160 kpc distant?

In terms of brightness, Koss+ 2014 write "Given the observed magnitude of g = 15.69 (SDSS), the galaxy absolute magnitude is Mg = -16.6, comparable to the Small Magellanic Cloud"; the morphology, however, is more like that of M32.

1 And that it's pretty much the same in all SDSS images ... which is what you expect, because the different images differ only in how the raw data ("the observation") was processed; there is only one SDSS observation (set of five-band 'CCD-readouts') of SDSS1133 (if it had been in Stripe 82, there would have been many more ...)
Thanks!--then I've got other 11 images from aladin!

Red:DSS_STScl
Green:SDSS_g
Blue:SDSS_u
 :oWow!Is that 'ejection' a Voorwerp?
other images:


SDSS_r
SDSS_g
SDSS_u


SDSS_i
SDSS_r
SDSS_g


SDSS_z
SDSS_i
SDSS_r


SDSS_r
SDSS_z
DSS_ESO


SDSS_r
SDSS_g
SDSS_u


SDSS_r
SDSS_r`1
SDSS_z


SDSS_g SDSS_i SDSS_z


SDSS_u SDSS_i SDSS_z


SDSS_u SDSS_r SDSS_z


SDSS_u
SDSS_g
SDSS_z


old images' thumbnails


« Last Edit: February 11, 2014, 08:16:27 am by Tony Wei »
Our greatest glory is not in never falling ,but in rising every time we fall.
——Nelson Rolihlahla Mandela

JeanTate

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #13 on: February 10, 2014, 12:33:03 pm »
Does that seem realistic?  ???

No.

Try something that's called a 'sanity check', or a 'sensibility check' (or 'reasonableness check')...

The brightest stars in the night sky are ~0 mag. The ones which are the greatest distance from us are ~1kpc distant. If you get an answer of mag ~-12, for a star that's 160kpc distant, something doesn't seem right, does it?

Or: in 1987 there was a supernova in the Large Magellanic Cloud (LMC). It certainly became 'naked eye' visible, but did not reach ~0 mag. The LMC is about the same distance from us as the SMC. Although SDSS1133 was, very likely, a supernova (albeit not of the same kind as SN1987A), if you get an answer of mag ~-12, something seems to be wrong, wouldn't you say?

Quote
absolute magnitude=brightness if object is 10 parsecs away
absolute magnitude=-16.6


160 kiloparsecs=160,000 parsecs

how many times further is 160,000 than 10?

160,000/10=16,000

The object is 16,000 times further than if it was 10 parsecs away.

the object is 16,000 times dimmer, then.

You might like to re-think this step ... if you move something so that it's twice as far away, does it appear half as bright?

Quote
16,000=about 4 and a bit orders of magnitude.

That's true, but is 'magnitude' in 'order of magnitude' the same as 'magnitude' as astronomers use the term? What could you do to find out?

PeterD

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Re: Thursday, 6 February 2014: SDSS1133, the Galaxy Zoo discovery that wasn't
« Reply #14 on: February 11, 2014, 03:25:19 pm »
A couple of things:

(i)     You are trying to distinguish absolute magnitude (ie mag at 10kpc - definition) from apparent magnitude (what you initially see/measure). They are actually linked via:

Absolute Magnitude = apparent magnitude - distance modulus

the distance modulus is given by

Distance modulus = 5log(d/10)

at this sort of distance. Where d is the distance measured in units of 10 kpc.

and the K-correction can be calculated using one of a variety of calculators here and it depends on redshift. but make sure that it works for the range of redshifts and wavelengths and with the cosmological parameters that you are using.

HOWEVER you can estimate the k-correction as Distance modulus(z) ~ 3z for z <0.5 for an Sa spiral in blue light at that sort of redshift. Strictly it depends on spectral energy distribution, observing passband and redshift.


(ii) Magnitudes for light measurements are based on a logarithmic scale using the Pogson ration which means that one magnitude is 2.512 times brighter than the previous one, so mag 2 is 2.512 times brighter than mag 1. It is defined so that 5 orders of magnitude corresponds to a brightness ratio of 100 times.

Orders of magnitude in maths, physics etc etc means essentially factors of ten so five orders of magnitude difference there means a factor of 105 (ie 100,000. To add to the fun, it is very context sensitive in its meaning. So If I say that something is two orders of magnitude greater than something else, it can mean it is 102 greater (ie 100 times). It can also mean something like "Well, I guess the new object does not have the same sort of value as the original object,  nor ten times it, but it could be say 80 times larger, or maybe even a couple of hundred times larger so we'll call it a hundred times greater. Give or take a bit. About." ;)

Hope that this helps. For comparison the Milky Way is expected to have an absolute magnitude iof about -20 viewed at 10kpc.