Galaxy Zoo Talk

Superspirals

  • KWillett by KWillett scientist, admin, translator

    A new paper on the most luminous spiral galaxies discovered in SDSS, including comparisons to the overall elliptical/spiral populations discovered in Galaxy Zoo 1.

    http://arxiv.org/pdf/1511.00659v1.pdf

    Any particular favorites in the list?

    Posted

  • JeanTate by JeanTate in response to KWillett's comment.

    Thanks for mentioning this Kyle.

    I am almost certain I have 'discovered' several of these, going back at least three years. However, as my Huds (humongous distant spiral) research focused on SDSS objects with z_sp > 0.3, most/almost all of the superspirals I found will not be in this paper.

    The superspirals which I discuss in my Zooniverse Letters (here, here, and here, dated from June 2012) have estimated stellar masses which would rank them in the top 10 of Table 1; e.g. J1557+2730's is 10^11.8 sols.

    What a pity I did not follow through on what I had discovered! 😭

    Posted

  • KWillett by KWillett scientist, admin, translator

    I wouldn't give up on this, then - there's still scientific value to be had, since your sample goes to higher redshift and didn't have the same UV-selection criteria.

    Posted

  • JeanTate by JeanTate in response to KWillett's comment.

    Thanks Kyle.

    Any particular favorites in the list?

    The one in Figure 4d looks mighty familiar ("2MASX J15430777+1937522", I think; SDSS J154307.77+193751.7, DR12 ObjId 1237665441532543024; DR7 ObjId 587739720307638323):

    enter image description here

    However, a search of the GZ Forum didn't turn it up 😦

    A quick search on some others shows that at least some were commented on, in the old GZ Forum; e.g. "Super spiral merger candidate 2MASXJ16014061+2718161" (in Fig 6); it's SDSS J160140.61+271815.9 (DR7 ObjId 587736619324801402) was noted by zooite Thyme Lawn, on August 02, 2007 (here), "Here are the 3 mergers that've most had me going 😮 so far.":

    enter image description here

    Posted

  • JeanTate by JeanTate in response to KWillett's comment.

    I wouldn't give up on this, then

    I've decided to give it a go, and attempt to write a paper on Huds.

    Anyone reading this who is interested in joining me, and becoming a co-author? If so, please send me a Message (via this v2 Talk's message system). 😃

    Posted

  • zutopian by zutopian

    Here is a news article, which was published on December 8, 2015.:

    Super Spiral Galaxies Amaze Astronomers by Ken Croswell
    http://www.scientificamerican.com/article/super-spiral-galaxies-amaze-astronomers/

    It contains a statement by GZ astronomer Mr. Keel, who wasn't affiliated with this research!

    Here is the press release, which was published some days ago!:

    Astronomers Discover Colossal 'Super Spiral' Galaxies, March 17, 2016
    http://www.jpl.nasa.gov/news/news.php?feature=6149

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    Thanks Zutopian,

    @JeanTate; would the minute chance of a pair of spirals rotating in the same direction and merging 'slowly' face-on (eg disk above disk) be such a special merger?

    EDIT: hmm this is exactly what is described in the SA article, nevermind

    Imagine the destruction of a merging spiral pair rotating same direction colliding edge-on

    Posted

  • Budgieye by Budgieye moderator

    Hi Jean, where do this one fit in on your list?

    Malin 1

    As of February 2015 it is the largest known spiral galaxy so far
    discovered, with an approximate diameter of 650,000 light-years
    (200,000 pc),[6][7][8] six and a half times the diameter of our Milky
    Way. It was discovered by astronomer David Malin in 1986 and is the
    first LSB galaxy verified to exist.[

    https://en.wikipedia.org/wiki/Malin_1

    enter image description here

    Posted

  • zutopian by zutopian

    @Budgieye @Jean

    Please be informed, that Malin-1 * (z=0.083) is mentioned in the paper "Superluminous Spiral Galaxies" (on page 9)!
    That's the paper, about which KWillett informed in the 1st post of this discussion!

    In below article, there is shown an image from the paper "DEEP OPTICAL IMAGES OF MALIN 1 REVEAL NEW FEATURES" by G. Galaz et al. (Published 18 Dec 2015) **. The spiral arms are visible on that image.:

    Featured Image: A New Look at Malin 1
    By Susanna Kohler on 18 January 2016
    http://aasnova.org/2016/01/18/featured-image-a-new-look-at-malin-1/

    '* SDSS link: http://cas.sdss.org/dr9/en/tools/explore/obj.asp?id=1237661068728139925
    '** arxiv link: http://arxiv.org/abs/1512.01095

    Posted

  • JeanTate by JeanTate in response to Budgieye's comment.

    Hi Budgieye, zutopian,

    Thanks very much for this! 😃

    Buta (2013) has a section called Giant Low Surface Brightness Galaxies (GLSBs). Malin 1 is mentioned several times, and cites several papers on it (e.g. Rahman+ 2007, Lelli+ 2010).

    In many ways, these GLSBs are similar to late-type spirals, except for the fact that their disks are huge and have low surface brightness. I suspect that few, if any, of the huge disks are visible in SDSS cutouts, and may also be undetected in the original data. IIRC, there's a recent paper on stacking of Stripe 82 SDSS data, done in a particularly rigorous way, which can reveal many low surface brightness features. I wonder if there are any GLSBs in Stripe 82?

    One more thing: in a universe where GR rules, surface brightness is not independent of distance; rather, it declines with redshift. That would make finding GLSBs among the Ogle+ (2016) Superspirals doubly difficult (and among Huds, even more so).

    Again, thanks for your question.

    Posted

  • zutopian by zutopian

    I found below paper, which was published in 1995, but curiously, it isn't listed as a reference in the paper "Superluminous Spiral Galaxies"!:

    Properties of the class of giant low surface brightness spiral galaxies

    We have obtained CCD surface photometry and optical spectroscopy for a sample of eight giant low surface brightness (LSB) spiral galaxies discovered in the course of a large survey for LSB galaxies. We find that these LSB giants have disks of larger scale length and lower central surface brightness than other spiral galaxies, although none have parameters as extreme as the prototype Malin 1. We find that the integrated colors of these LSB giants are redder than the integrated colors of smaller LSB galaxies, and that the LSB galaxies of all sizes follow a relation between redder colors and increasing disk scale length. Two of these eight LSB giants have active nuclei with the broad permitted lines characteristic of a Seyfert 1 nucleus, and one has the narrow lines of a Seyfert 2. The colors and absorption line indices of the bulges of these giants are indistinguishable from those of high surface brightness (HSB) spirals, suggesting that their bulges have similar stellar populations and evolutionary histories. We also observed four and detected three of these galaxies in the 21 cm line of H I. These LSB giants generally have high total H I masses, although none is as extreme as Malin 1.
    Finally, the small-scale environments around these galaxies reveal several nearby companions. These LSB giants are at least as likely as smaller LSB galaxies to have close companions, and their average number of neighbors approaches that of HSB galaxies.

    Authors: Sprayberry, D.; Impey, C. D.; Bothun, G. D.; Irwin, M. J.
    Affiliation: AA(University of Arizona, Tucson, AZ), AB(University of Arizona, Tucson, AZ), AC(University of Arizona, Tucson, AZ), AD(University of Arizona, Tucson, AZ)
    Astronomical Journal (ISSN 0004-6256), vol. 109, no. 2, p. 558-571 (AJ Homepage)
    Publication Date: 02/1995
    http://adsabs.harvard.edu/abs/1995AJ....109..558S

    Posted

  • JeanTate by JeanTate

    "On the Classification of UGC1382 as a Giant Low Surface Brightness Galaxy" (arXiv:1607.02147, link is to the abstract):

    We provide evidence that UGC1382, long believed to be a passive elliptical galaxy, is actually a giant low surface brightness (GLSB) galaxy which rivals the archetypical GLSB Malin 1 in size. Like other GLSB galaxies, it has two components: a high surface brightness disk galaxy surrounded by an extended low surface brightness (LSB) disk. For UGC1382, the central component is a lenticular system with an effective radius of 6 kpc. Beyond this, the LSB disk has an effective radius of ~38 kpc and an extrapolated central surface brightness of ~26 mag/arcsec^2. Both components have a combined stellar mass of ~8x10^10 M_sun, and are embedded in a massive (10^10 M_sun) low-density (❤️ M_sun/pc^2) HI disk with a radius of 110 kpc, making this one of the largest isolated disk galaxies known. The system resides in a massive dark matter halo of at least 2x10^12 M_sun. Although possibly part of a small group, its low density environment likely plays a role in the formation and retention of the giant LSB and HI disks. We model the spectral energy distributions and find that the LSB disk is likely older than the lenticular component. UGC1382 has UV-optical colors typical of galaxies transitioning through the green valley. Within the LSB disk are spiral arms forming stars at extremely low efficiencies. The gas depletion time scale of ~10^11 yr suggests that UGC1382 may be a very long term resident of the green valley. We find that the formation and evolution of the LSB disk is best explained by the accretion of gas-rich LSB dwarf galaxies.

    Here it is in SDSS (you can just make out the brighter spiral arms):

    enter image description here

    Not imaged by DECaLS 😦 Maybe CHFT? Or Subaru?

    Posted

  • zutopian by zutopian in response to JeanTate's comment.

    "On the Classification of UGC1382 as a Giant Low Surface Brightness Galaxy" (arXiv:1607.02147, link is to the abstract):
    We provide evidence that UGC1382, long believed to be a passive elliptical galaxy, is actually a giant low surface brightness (GLSB) galaxy which rivals the archetypical GLSB Malin 1 in size.(...)

    Well, UGC 1382 had been presented as a "spiral galaxy" in an "Object of the Day" (old GZ forum) by GZ astronomer Edd some years ago!
    http://www.galaxyzooforum.org/index.php?topic=273270.msg228420#msg228420
    Curiously, the GZ astronomers didn't write a paper about this discovery!

    One of the ADS Refs. is following paper by Sugata Kaviraj, who is involved in GZ.:
    Peculiar early-type galaxies in the SDSS Stripe82
    Statement on the 2nd page:

    The objects are carefully assigned to three main morphological classes: early-type galaxies (ETGs), late-type galaxies (LTGs) and ‘Sa-like’ systems which are bulge-dominated galaxies with faint spiral features that are visible in the Stripe82 imaging but
    invisible in the standard-depth images.

    Author: Sugata Kaviraj
    (Submitted on 21 Apr 2010)
    https://arxiv.org/abs/1004.3775

    PS: I copied my above post to the GZ Talk topic "Galaxies in the News".

    Posted

  • zutopian by zutopian

    This discussion is initially about "Superluminous Spirals", which are also giant and massive! Besides it is about "Giant Low Surface Brightness Spirals"!

    Here is a new paper, which might be related.:

    The Circum-Galactic Medium of MASsive Spirals I: Overview and a Case Study of NGC 5908
    Authors:Jiang-Tao Li, Joel N. Bregman, Q. Daniel Wang, Robert A. Crain, Michael E. Anderson

    The Circum-Galactic Medium of MASsive Spirals (CGM-MASS) is a project studying the overall content, physical and chemical properties, and spatial distributions of the multi-phase circum-galactic medium (CGM) around a small sample of the most massive isolated spiral galaxies in the local Universe. We introduce the sample and present a detailed case study of the XMM-Newton observation of the hot gas halo of NGC5908. (...)

    (Submitted on 5 Aug 2016)
    http://arxiv.org/abs/1608.02033

    Posted

  • zutopian by zutopian

    New paper.:

    Future Prospects: Deep Imaging of Galaxy Outskirts using Telescopes Large and Small
    Roberto Abraham, Pieter van Dokkum, Charlie Conroy, Allison Merritt, Jielai Zhang, Deborah Lokhorst, Shany Danieli, Lamiya Mowla

    The Universe is almost totally unexplored at low surface brightness levels. In spite of great progress in the construction of large telescopes and improvements in the sensitivity of detectors, the limiting surface brightness of imaging observations has remained static for about forty years. Recent technical advances have at last begun to erode the barriers preventing progress. In this Chapter we describe the technical challenges to low surface brightness imaging, describe some solutions, and highlight some relevant observations that have been undertaken recently with both large and small telescopes. Our main focus will be on discoveries made with the Dragonfly Telephoto Array (Dragonfly), which is a new telescope concept designed to probe the Universe down to hitherto unprecedented low surface brightness levels. We conclude by arguing that these discoveries are probably only scratching the surface of interesting phenomena that are observable when the Universe is explored at low surface brightness levels.

    https://arxiv.org/abs/1612.06415
    (Submitted on 19 Dec 2016)

    Posted