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#1
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What is this galaxy?
Anyone know what kind of galaxy this galaxy might be?
http://skyserver.sdss.org/dr13/en/to...189&dec=13.076 It has a ring around the central bulge, but no apparent black hole central high intensity region. Looks a little like a polar ring galaxy, but the ring is within the bulge near the outer radius of the bulge. Easiest to see if you zoom in 2 clicks, then invert the image. it's right next to a disrupted galaxy in Virgo Cluster (which can be seen by zooming out a couple clicks. Looks like a galaxy without a black hole, unless the small bright knot to the north is an ejected black hole. Thanks, rt |
#3
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What is this galaxy?
The galaxy is NGC 4435, a.k.a. VCC 1030 and at least a dozen other
names. Its morphology is classified as SBO (plus some other stuff), which means it's a barred lenticular (or S0) galaxy. If you click on the Explore link on the SDSS page (your link), and then on the NED search link, you'll get a lot of information about this galaxy, including the fact that it appears in some 363 papers (references), all of which can be accessed via a link. There are also 12 notes, one of which says, in part "Because of the dust, it is also impossible to assess the presence of a nucleus". |
#4
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What is this galaxy?
There are also 12 notes, one of
which says, in part "Because of the dust, it is also impossible to assess the presence of a nucleus". Doesn't look like dust is blocking view to center, if it is, the dust is extraordinarily smooth. It looks like it ran right through the center of the adjacent galaxy, and lost it's black hole to the larger galaxy, with the stars continuing on, blowing out into a spherical shell that has the appearance of a circle. But sorting out what is really going on would be a challenge. I'll have to read some of those papers. But it really looks like it's a galaxy without a central massive BH............and that's unusual if so. Wonder if one of the papers shows spectroscopy of the central region, I'll have to check. Thanks for letting me know to click on the references to see papers. rt |
#5
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What is this galaxy?
In article ,
writes: Doesn't look like dust is blocking view to center, if it is, the dust is extraordinarily smooth. It looks like it ran right through the center of the adjacent galaxy, and lost it's black hole to the larger galaxy, with the stars continuing on, blowing out into a spherical shell that has the appearance of a circle. But sorting out what is really going on would be a challenge. I'll have to read some of those papers. But it really looks like it's a galaxy without a central massive BH............and that's unusual if so. Wonder if one of the papers shows spectroscopy of the central region, I'll have to check. Even though most galaxies probably contain central supermassive black holes, they are not always active. Even if they are, radiation can be directed in some direction other than towards us and/or can be obscured by dust. There is no way you can tell just by looking at an SDSS image. There are probably many images of this galaxy in much higher resolution. (The interesting thing about SDSS is not its resolution or depth, neither of which are particularly good (it is a small telescope at a site which is much worse than the best, exposures are not particularly long), but rather the fact that it images a large area of the sky and does so in survey mode, rather than with targeted observations (which allow one to study only objects which are already known).) |
#6
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What is this galaxy?
On Saturday, December 31, 2016 at 10:47:34 PM UTC-5, wr=
ote: {snip} Doesn't look like dust is blocking view to center, if it is, the dust is extraordinarily smooth. It looks like it ran right through the center of the adjacent galaxy, and lost it's black hole to the larger galaxy, with the stars continuing on, blowing out into a spherical shell that has the appearance of a circle. I'm sure you already know this: the images you see on the SDSS site are heavily processed representations of the actual SDSS data, which can be downloaded as FITS files (all the way from the raw data to the nicest cleaned data). Independent survey observations which may include this galaxy are GALEX (UV), DECaLS (optical), PS1 (optical), WISE (IR), Akari (IR), IRAS (IR), Planck (microwave), and FIRST (1.4 GHz). This being a Virgo cluster galaxy, it may have been the target of dedicated observations by 8-10m class facilities (e.g. Gemini, Subaru, Keck, VLT, LBT, and GCT), as well the Hubble; if so, some imaging data may be in the public domain (in the form of FITS files). One terrific thing about data - not JPG or PNG images - in the public domain is that you can download it and do your own processing; DS9 is great for this (although the User Manual is rather, um, terse). But sorting out what is really going on would be a challenge. I'll have to read some of those papers. But it really looks like it's a galaxy without a central massive BH............and that's unusual if so. Wonder if one of the papers shows spectroscopy of the central region, I'll have to check. As PH has already noted, showing robustly that a galaxy as massive as NGC 4435 has no central SMBH could be extraordinarily difficult, and not just if it's quiescent. Thanks for letting me know to click on the references to see papers. You're welcome. |
#7
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What is this galaxy?
On 01/01/2017 03:47, wrote:
There are also 12 notes, one of which says, in part "Because of the dust, it is also impossible to assess the presence of a nucleus". Doesn't look like dust is blocking view to center, if it is, the dust is extraordinarily smooth. Looks can be deceptive! IRAS infrared imaging was used to better determine its luminosity profile in a paper from 2009 (fig 4 p1995): http://iopscience.iop.org/article/10...138/6/1990/pdf Since VCC1030 aka NGC4435 has a detected unresolved point source at its core in VLA 8GHz radio observations I think it is highly likely that the SM black hole is still there but the stripping of dust and gas out of the smaller galaxy by the previous collision has starved it of food. It looks like it ran right through the center of the adjacent galaxy, and lost it's black hole to the larger galaxy, with the stars continuing on, blowing out into a spherical shell that has the appearance of a circle. It is dynamically very difficult for this to happen without a 3 body collision of roughly similar mass objects. But there *is* observational evidence for a weakly emitting radio point source at the core (ie a BH). At least one group thinks that some of what we see in this Virgo field is confused by local galactic cirrus in the line of sight. http://mnrasl.oxfordjournals.org/con...1/L26.full.pdf But sorting out what is really going on would be a challenge. I'll have to read some of those papers. But it really looks like it's a galaxy without a central massive BH............and that's unusual if so. Wonder if one of the papers shows spectroscopy of the central region, I'll have to check. Having been and had a look at it on CDS Strasbourg I am actually more interested in the bright linear source with no obvious optical counterpart that appears on XMM-Newton EPIC at about 10 O'clock from the emissions of NGC 4438 (or is it an aeretfact)?. http://cdsportal.u-strasbg.fr/?target=NGC%20%204435 Unfortunately Chandra field of view doesn't include it. http://chandra.harvard.edu/photo/200...438/index.html BTW It isn't a good idea to concentrate on the weirdest most twisted tree that you can find if you want to understand how trees work. Arp went down that path in an attempt to debunk the Big Bang (and to be fair found a lot of very curious interacting galaxies as a result) https://ned.ipac.caltech.edu/level5/..._contents.html It is ARP120 in that catalogue. VLT Cosmic Gem's programme observed this pair in 2011 - rather pretty. https://www.eso.org/public/news/eso1131/ -- Regards, Martin Brown |
#8
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What is this galaxy?
On Thursday, January 5, 2017 at 8:06:03 PM UTC-8, Martin Brown wrote:
On 01/01/2017 03:47, wrote: Martin said: Having been and had a look at it on CDS Strasbourg I am actually more interested in the bright linear source with no obvious optical counterpart that appears on XMM-Newton EPIC at about 10 O'clock from the emissions of NGC 4438 (or is it an aeretfact)?. http://cdsportal.u-strasbg.fr/?target=NGC%20%204435 I clicked on above link but didn't see the feature you mentioned. I did see a faint straight line, (asteroid streak?) at maybe 1 oclock and 3 galactic radii away. Curious about how to see the other image you mentioned, as much to learn about how to use another viewer as anything. I'll be careful regarding twisted trees. ;-) rt |
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