Galaxy Zoo Talk

Galaxies in the news

  • Budgieye by Budgieye moderator

    Post news about galaxies. A corresponding image from from our classification studies would be welcome eg SDSS, DECaLS, CFHT, Hubble

    To go to the end click https://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0001xte?page=0

    Posted

  • Budgieye by Budgieye moderator

    Crater 2 is a dwarf galaxy discovered orbiting the Milky Way

    " the discovery of the Crater 2 dwarf galaxy, identified in imaging data of the VST ATLAS survey. Given its half-light radius of ∼1100 pc, Crater 2 is the fourth largest satellite of the Milky Way, surpassed only by the LMC, SMC and the Sgr dwarf.

    https://en.wikipedia.org/wiki/Crater_2_dwarf_galaxy

    http://mnras.oxfordjournals.org/content/early/2016/04/13/mnras.stw733.abstract

    Posted

  • Budgieye by Budgieye moderator

    A huge black hole found in a solitary elliptical galaxy.

    Behemoth Black Hole Found in an Unlikely Place

    enter image description here NGC 1600

    NGC1600

    Astronomers have uncovered a near-record-breaking supermassive black
    hole, weighing 17 billion suns, in an unlikely place: in the center of
    a galaxy in a sparsely populated area of the universe. The
    observations, made by NASA's Hubble Space Telescope and the Gemini
    telescope in Hawaii, could indicate that these monster objects may be
    more common than once thought.

    http://hubblesite.org/newscenter/archive/releases/2016/12/full/

    Posted

  • Budgieye by Budgieye moderator

    Dark matter dwarf galaxy discovered.

    It is the white blip at 7 o'clock near the red arc.

    The center galaxy is an elliptical galaxy called SDP.81 redshift = 0.299640

    The lensed galaxy is a star-forming galaxy redshift = 3.042000 It is made into an arc by the gravitational lensing of the center ellipical galaxy.

    The dark matter dwarf galaxy is orbiting the center galaxy, and it is disturbing the nice symmetical ring that the center galaxy has made.

    The dwarf galaxy doesn't have enough stars to be massive enough to affect the gravitational lensing in this way.

    Therefore, the dwarf galaxy must have lots of dark matter, which adds to its mass.

    enter image description here
    Distant Galaxy SPD 81 is deformed by the red elliptical into the red gravitational arc

    Composite image of the gravitational lens SDP.81 showing the distorted
    ALMA image of the more distant galaxy (red arcs) and the Hubble
    optical image of the nearby lensing galaxy (blue center object). By
    analyzing the distortions in the ring, astronomers have determined
    that a dark dwarf galaxy (data indicated by white dot near left lower
    arc segment) is lurking nearly 4 billion light-years away. Image
    credit: Y. Hezaveh, Stanford University / ALMA / NRAO / ESO / NAOJ /
    NASA / ESA / Hubble Space Telescope

    http://www.skyandtelescope.com/astronomy-news/dark-dwarf-galaxy-discovered/?utm_source=newsletter&utm_campaign=sky-mya-nl-160422&utm_content=838491_SKY_HP_eNL_160422&utm_medium=email

    enter image description here

    Stars seen forming in a far-off galaxy

    Nature 522, 259 (18 June 2015) doi:10.1038/522259a
    Published online 17 June 2015http://www.nature.com/nature/journal/v522/n7556/full/522259a.html

    What can we see? nothing - need radio telescopes.

    enter image description here

    The Atacama Large Millimeter/submillimeter Array is an astronomical interferometer of radio telescopes in the Atacama desert of northern Chile

    enter image description here nothing to see on SDSS because too red-stretched into the IR and radio waves.

    enter image description here

    http://skyserver.sdss.org/dr12/en/tools/explore/Summary.aspx?id=1237648722285101574

    enter image description here

    enter image description here enter image description here
    http://cdn4.sci-news.com/images/2016/04/image_3788-SDP-81-Dwarf-Galaxy.jpg

    published image, red arc is 3" high, and SDSS image at same scale

    Posted

  • Budgieye by Budgieye moderator

    APOD website: Galaxy Evolution Tracking Animation gravity causes clumps of matter to form into galaxies which immediately begin falling toward each other
    Video Credit: Donna Cox (AVL NCSA/U. Illinois) et al., NASA's GSFC, AVL, NCSA

    Explanation: How did the universe evolve from such a smooth beginning?
    To help understand, computational cosmologists and NASA produced the
    featured time-lapse animated video depicting a computer simulation of
    part of the universe. The 100-million light-year simulation starts
    about 20 million years after the Big Bang and runs until the present.
    After a smooth beginning, gravity causes clumps of matter to form into
    galaxies which immediately begin falling toward each other. Soon, many
    of them condense into long filaments while others violently merge into
    a huge and hot cluster of galaxies. Investigating of potential
    universe attributes in simulations like this have helped shape the
    engineering design the James Webb Space Telescope, currently scheduled
    for launch in late 2018.

    http://apod.nasa.gov/apod/ap160530.html

    This might explain why we large galaxies with many small galaxies around them.

    Posted

  • Budgieye by Budgieye moderator

    So far, astronomers have detected about 12 dwarf galaxies orbiting around our Milky Way Galaxy.

    Are there many more dwarf galaxies around us, but they are too dim to be seen?

    Computer simulations say that there should be more of these dwarf galaxies. Computer simulations (see image) were done with dark matter, and assume that there are stars associated with the amount of dark matter.

    But when stars explode, they push hydrogen gas away. Dwarf galaxies lose their hydrogen, and can't make more stars, and the dwarf galaxies get dimmer.

    Astronomers may have solved the case of the Milky Way's missing
    satellite galaxies. The solution? The galaxies never existed. Good
    explanation in Sky and Telescope magazine
    http://www.skyandtelescope.com/astronomy-news/missing-dwarf-galaxies-never-were/?utm_source=newsletter&utm_campaign=sky-mya-nl-

    enter image description here

    160617&utm_content=855427_SKY_HP_eNL_160617&utm_medium=email

    http://arxiv.org/abs/1602.05957 Wetzel et al Low-mass "dwarf" galaxies represent the most significant challenges to the cold dark matter (CDM) model of cosmological structure formation. Because these faint galaxies are (best) observed within the Local Group of the Milky Way (MW) and Andromeda (M31), understanding their formation in such an environment is critical. We present the first results from the Latte Project: the Milky Way on FIRE (Feedback in Realistic Environments). This simulation models the formation of a MW-mass galaxy to z = 0 within LCDM cosmology, including dark matter, gas, and stars at unprecedented resolution: baryon mass of 7070 M_sun at spatial resolution down to 1 pc. Latte was simulated using the GIZMO code with a mesh-free method for accurate hydrodynamics and the FIRE model for star formation and explicit feedback within a multi-phase interstellar medium. For the first time, Latte self-consistently resolves the internal structure of dwarf galaxies that form around a MW-mass host down to M_star > 10^5 M_sun. Latte's population of dwarf galaxies agrees well with those observed in the Local Group across a broad range of properties: (1) distributions of stellar masses and stellar velocity dispersions (dynamical masses), including their joint relation, (2) the mass-metallicity relation, and (3) a diverse range of star-formation histories, including their mass dependence. Thus, Latte produces a realistic population of dwarf galaxies at M_star > 10^5 M_sun that does not suffer from the "missing satellites" or "too big to fail" problems of small-scale structure formation. We conclude that baryonic physics can reconcile observed dwarf galaxies with standard LCDM cosmology.

    http://arxiv.org/pdf/1602.05957v1.pdf

    Posted

  • Budgieye by Budgieye moderator

    Hitomi Mission Charts Hot Winds of a Galaxy Cluster for the First Time "For the first time, we have mapped the motion of the X-ray-emitting gas in a cluster of galaxies and determined its velocity structure over a wide range of spatial scales,"

    The bizarre object at the center is NGC 1275, the cluster's central galaxy and itself a prominent source of X-ray and radio emission. At the galaxy's core lies a supermassive black hole activated by infalling matter. Glowing filaments extending from the galaxy trace bubbles of gas blown violently outward by the black hole. Despite this activity, Hitomi measurements show that hot cluster gas in the vicinity is moving at cosmically modest speeds.

    http://www.nasa.gov/feature/goddard/2016/hitomi-mission-charts-hot-winds-of-a-galaxy-cluster-for-the-first-time

    NGC1275 #NGC 1275

    http://www.nasa.gov/feature/goddard/2016/hitomi-mission-charts-hot-winds-of-a-galaxy-cluster-for-the-first-time

    enter image description here

    enter image description here SDSS dr12

    http://skyserver.sdss.org/SkyserverWS/dr12/ImgCutout/getjpeg?TaskName=Skyserver.Chart.Image&ra=49.9323233236051&dec=41.4751177635532&scale=1.584508&width=450&height=400&opt=&query=

    http://skyserver.sdss.org/SkyserverWS/dr12/ImgCutout/getjpeg?TaskName=Skyserver.Chart.Image&ra=49.9323233236051&dec=41.4751177635532&scale=0.396127&width=1000&height=600&opt=&query=

    enter image description here

    For great image, see https://apod.nasa.gov/apod/ap170405.html

    enter image description here SDSS

    http://skyserver.sdss.org/dr9/en/tools/explore/obj.asp?ra=49.950652847030476&dec=41.51168502888517

    http://zooniverse-static.s3.amazonaws.com/www.galaxyzoo.org/subjects/standard/56f3e0405925d900430078bd.jpeg

    Posted

  • Budgieye by Budgieye moderator

    At left, in optical light, UGC 1382 appears to be a simple elliptical galaxy. But spiral arms emerged when astronomers incorporated ultraviolet and deep optical data (middle). Combining that with a view of low-density hydrogen gas (shown in green at right), scientists discovered that UGC 1382 is gigantic.
    Credits: NASA/JPL/Caltech/SDSS/NRAO/L. Hagen and M. Seibert

    enter image description here

    http://www.nasa.gov/feature/jpl/frankenstein-galaxy-surprises-astronomers

    enter image description here

    http://skyserver.sdss.org/SkyserverWS/dr12/ImgCutout/getjpeg?TaskName=Skyserver.Chart.Image&ra=28.6710165024155&dec=-0.14336172069559&scale=1.584508&width=512&height=512&opt=&query=

    http://skyserver.sdss.org/dr12/en/tools/explore/Summary.aspx?id=1237666407918075971

    https://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ0001ol2 page 2 by JeanTate

    Posted

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

    I wrote about this galaxy in another thread (here).

    Posted

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

    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 did my above post also in the GZ Talk topic "Superspirals" today!

    Posted

  • Budgieye by Budgieye moderator

    X Marks the Spot for Milky Way Formation Our Milky way galaxy has an X-shaped nucleus.

    The Milky Way is an example of a disk galaxy -- a collection of stars
    and gas in a rotating disk. In these kinds of galaxies, when the thin
    disk of gas and stars is sufficiently massive, a “stellar bar” may
    form, consisting of stars moving in a box-shaped orbit around the
    center. Our own Milky Way has a bar, as do nearly two-thirds of all
    nearby disk galaxies.

    Over time, the bar may become unstable and buckle in the center. The
    resulting “bulge” would contain stars that move around the galactic
    center, perpendicular to the plane of the galaxy, and in and out
    radially. When viewed from the side, the stars would appear
    distributed in a box-like or peanut-like shape as they orbit. Within
    that structure, according to the new study, there is a giant X-shaped
    structure of stars crossing at the center of the galaxy.

    A bulge can also form when galaxies merge, but the Milky Way has not
    merged with any large galaxy in at least 9 billion years.

    http://www.nasa.gov/feature/jpl/x-marks-the-spot-for-milky-way-formation

    enter image description here

    Posted

  • zutopian by zutopian

    Referring to above post: The below paper questions the apparent discovery "x-shaped bulge of the MW".:

    A case against an X-shaped structure in the Milky Way young bulge
    Martin Lopez-Corredoira
    (Submitted on 30 Jun 2016)
    https://arxiv.org/abs/1606.09627

    Posted

  • Budgieye by Budgieye moderator

    Hmm, picture vs computer modelling. Which do I believe?

    Posted

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

    Hmm, picture vs computer modelling. Which do I believe?

    In the paper by Ness & Lang there is given following statement.:

    The WISE image of the Milky Way bulge shows that the X-shaped nature of the Milky Way bulge is self-evident and irrefutable.

    https://arxiv.org/abs/1603.00026

    In the paper (on page 9) by Mr Lopez-Corredoira there is given a statement about the paper by Ness & Lang!

    Posted

  • zutopian by zutopian

    GZ Talk discussion:

    Dragonfly 44 is 99.99% dark matter
    https://talk.galaxyzoo.org/#/boards/BGZ0000001/discussions/DGZ00028ak

    Posted

  • Budgieye by Budgieye moderator

    NGC 1316: After Galaxies Collide "Astronomers suspect the giant galaxy of colliding with smaller neighbor NGC 1317 seen just above, causing far flung loops and shells of stars". https://apod.nasa.gov/apod/ap170202.html

    enter image description here

    NGC 1316: After Galaxies Collide Image Credit & Copyright: Steve
    Mazlin, Warren Keller, and Steve Menaker (SSRO / UNC / PROMPT / CTIO)
    Explanation: An example of violence on a cosmic scale, enormous
    elliptical galaxy NGC 1316 lies about 75 million light-years away
    toward Fornax, the southern constellation of the Furnace.
    Investigating the startling sight, astronomers suspect the giant
    galaxy of colliding with smaller neighbor NGC 1317 seen just above,
    causing far flung loops and shells of stars. Light from their close
    encounter would have reached Earth some 100 million years ago. In the
    deep, sharp image, the central regions of NGC 1316 and NGC 1317 appear
    separated by over 100,000 light-years. Complex dust lanes visible
    within also indicate that NGC 1316 is itself the result of a merger of
    galaxies in the distant past. Found on the outskirts of the Fornax
    galaxy cluster, NGC 1316 is known as Fornax A. One of the visually
    brightest of the Fornax cluster galaxies it is one of the strongest
    and largest radio sources with radio emission extending well beyond
    this telescopic field-of-view, over several degrees on the sky.

    Posted

  • Budgieye by Budgieye moderator

    Hubble image - blue stars are made red, because it looks "hotter"

    https://www.nasa.gov/image-feature/goddard/2016/hubble-reveals-stellar-fireworks-in-skyrocket-galaxy

    enter image description here

    enter image description here

    http://skyserver.sdss.org/dr12/en/tools/explore/Summary.aspx?id=1237665369046712390

    SDSS J114107.49+322537.3

    enter image description here

    enter image description here

    http://skyserver.sdss.org/dr12/en/tools/explore/Summary.aspx?id=1237665369046712391

    LEDA 36254 Kiso 5639

    Posted

  • zoob1172 by zoob1172

    https://arxiv.org/pdf/1605.02822.pdf

    Posted

  • Budgieye by Budgieye moderator in response to zoob1172's comment.

    zoob1172, there is no need to post the link to the article. It is easy to access the information from the SDSS link and NED. You can look up the one following this.

    Posted

  • Budgieye by Budgieye moderator in response to zoob1172's comment.

    Hubble reconstructs an image of a galaxy from lensed image.

    https://www.nasa.gov/feature/goddard/2017/hubble-sees-clumps-of-new-stars-in-distant-galaxy

    Posted

  • Ghost_Sheep_SWR by Ghost_Sheep_SWR

    And in the category 'is this really real?' (As in it is such an amazing feat they accomplished, I believe it 😃 ); Supermassive Black Holes 'seen' orbiting each other. After taking images for ~12 years they detected movement of a bit more than an incredible 1 microarcsecond / year, which showed that the SMBH's orbit each other.

    enter image description here

    Very Long Baseline Array image of the central region of galaxy 0402+379, showing a pair of supermassive black holes (labeled C1 and C2) in orbit around each other.
    Credit: Bansal et al., NRAO/AUI/NSF and Space.com

    https://www.space.com/37369-supermassive-black-holes-orbiting-each-other.html

    Posted