Astronomers have created a detailed atlas of almost 400000 #galaxies in our cosmic neighborhood.
The Siena Galaxy Atlas is a treasure trove of information for researchers investigating everything from #galaxy formation and evolution to dark matter and gravitational waves.
It’s also freely available online for the public to explore.
The paper-reading binge continues. Here's one about a new way to detect if galaxies are experiencing ram pressure, or rather, an important validation of a model that seems to work surprisingly well. Now there are nicely resolved maps showing in convincingly consistent detail that the CII/FIR ratio really does work very well for this. Nothing revolutionary here, but curiously satisfying all the same.
#Science
#Astronomy
#Astrophysics
#Galaxies
https://llittlephysicists.blogspot.com/2023/10/a-pleasant-shock.html
On a really fun little paper looking at whether globular clusters could be the remains of tidally-disrupted satellite galaxies. Because that's how I roll on a Friday night.
https://llittlephysicists.blogspot.com/2023/10/hidden-in-plain-sight.html
Have to say that my new tablet makes reading papers an absolute joy - I've read five of the damn things in the last day alone. But more on that in due course.
Anyway, this one is about the mass of the Milky Way. The press releases run with the boring headlines about the Galaxy being less massive than from previous measurements, but that's not what's interesting. What's interesting is that this uses not only new data but a fundamentally better technique, and it points to the Milky Way being (in some ways) a genuinely unusual spiral galaxy. This always gets a lot of pushback from the anti-Standard Model crowd, who insist that the Milky Way must be typical and any attempt to invoke peculiarities when anything unexpected is found is somehow shifting the goalposts. Essentially they claim that everything is being fudged, that if something appears to contradict the prediction, we somehow revise out data so that the Milky Way is a special case, and not the typical example we should presume it to be.
And that's a legitimate concern : we don't want to risk dismissing the much more interesting prospect of finding something genuinely contradicting the model ! But to me at least, that's not what's being done. Absolutely, we should presume we're a typical spiral. But when data demonstrates unequivocally that this isn't the case, we have to account for this. To ignore our peculiarities would be every bit as bad as inventing them.
#Science
#Astronomy
#Galaxies
#Astrophysics
https://llittlephysicists.blogspot.com/2023/10/keplers-krazy-kurves.html
A new study finds two new polar ring galaxies and speculates wildly that there might be ten times as many as previously thought. Well, by "speculates wildly", I really mean, "carefully considers the possibility", but that's not very clickbaity.
#Astronomy
#Science
#Space
#Galaxies
https://llittlephysicists.blogspot.com/2023/10/what-do-you-do-if-you-like-galaxy-so.html
Wheee, I read... another paper ! Two in two days, like a good little scientist...
This one is about a dark galaxy candidate from FAST. Not the amazing one that came out in February, but another one. I can't say I like this as a publication though : it contains no new data, seems to have scraped the contours from an early publication rather than the data itself, draws all of its conclusions based on quite marginal results, and uses annoying, unnecessary terminology. None of which means it's wrong, but it just doesn't contribute very much.
https://llittlephysicists.blogspot.com/2023/09/a-dark-galaxy-by-any-other-name.html
Wow I finally managed to read a paper... here's one about molecular gas (or interestingly, lack thereof) in the Leo Ring. Looks like star formation outside galaxies does not work in the same way as within them.
#Science
#Space
#Astronomy
#Galaxies
https://llittlephysicists.blogspot.com/2023/09/lights-in-darkness.html
Euclid’s VISible instrument (VIS) will take super sharp images of billions of #galaxies to measure their shapes. Looking closely at this first image, we already get a glimpse of the bounty that VIS will bring; whilst a few galaxies are very easy to spot, many more are fuzzy blobs hidden amongst the #stars, waiting to be unveiled by Euclid in the #future.
By combining distance information with that on galaxy shapes measured by VIS, we will be able to map how galaxies are distributed throughout the #Universe, and how this distribution changes over time. Ultimately, this 3D map will teach us about dark matter and dark energy.
#darkMatter #science #space #exploration #news #photo #galaxy #esa
My website host stopped providing their site builder earlier this year and I haven't been able to get around to using their new version... until now. Here's the first step in the process of rebuilding and redesigning. God knows it needed doing anyway, I haven't touched the design since 2008. At least now it actually formats correctly on mobile devices !
This new version is much more science-oriented than previously. So I've started with some basic introductions to the research I'm interested in and involved in, and - goodness me, I've actually managed to write concisely, will wonders new cease... More CV-type stuff to be added next. Then the restoration of all the old content.
Somewhat annoyingly, all the old stuff is still accessible via ftp, but not through web browsers. Apparently something went funky during the import. Meh, I don't care, this is a good excuse to be forced to start from scratch; if the import had succeeded I probably wouldn't have bothered.
Ahh, the latest "there's no dark matter, it's all just MOND" claim. The press release sounds awfully convincing, as usual, but every damn time one digs into MONDian claims, one finds they're at best heavily overstated. I'm doing a lengthy write-up on MOND versus CDM from a philosophy of science perspective, but I'll probably skip this particular claim.
The latest Gaia data indicates that Newtonian-like gravity is completely sufficient, and that the MOND-like behaviour, which should take over in the low acceleration regime if the idea is correct, is absent. It’s absent, in fact, at the ~16-sigma level: a tremendous significance. The paper that’s been getting the recent publicity... draws the opposite conclusion: claiming to see a better agreement with MOND than with Newtonian gravity, and at just over 5-sigma significance.
It’s not that someone is definitively right and someone is definitively wrong; it’s that there are assumptions that go into choosing and analyzing the data, and simply by making different assumptions (and not quantifying the associated errors that come along with making them), you can wind up drawing vastly different conclusions. This problem will always plague an observational science like astronomy, and is almost certainly the culprit behind another wild, dubious assertion that was made in 2023: that black holes are the cause of the dark energy in our Universe.
#Science
#Galaxies
#DarkMatter
#MOND
https://bigthink.com/starts-with-a-bang/binary-stars-prove-modified-gravity/
On that massive galaxy in the press releases without dark matter. A fun object, not at all clear what's going on ! But not a terribly well-written paper IMHO.
#Science
#Galaxies
#DarkMatter
#Astrophysics
https://llittlephysicists.blogspot.com/2023/07/massively-missing-matter.html
This infrared image from NASA’s James Webb Space Telescope (JWST) was taken for the JWST Advanced Deep Extragalactic Survey, or JADES, program. It shows a portion of an area of the sky known as GOODS-South, which has been well studied by the Hubble Space Telescope and other observatories. More than 45,000 galaxies are visible here.
#Czech article on disentangling signal from noise in radio astronomy. Nobody has told me not to share the original English version though, so you can read that here.
#Science
#Astronomy
#Galaxies
#Noise
https://vesmir.cz/cz/casopis/archiv-casopisu/2023/cislo-6/hledani-galaxii-kupce-sumu.html
