Slashdot Mirror
Improved Estimates of the Distance To the Large Magellanic Cloud
Long-time Slashdot reader colinwb writes: A team of researchers has published a letter in Nature (2019) estimating the distance to the Large Magellanic Cloud" to a precision of one per cent; Arxiv (2019).
The Arxiv abstract: In the era of precision cosmology, it is essential to empirically determine the Hubble constant with an accuracy of one per cent or better. At present, the uncertainty on this constant is dominated by the uncertainty in the calibration of the Cepheid period — luminosity relationship (also known as Leavitt Law). The Large Magellanic Cloud has traditionally served as the best galaxy with which to calibrate Cepheid period-luminosity relations, and as a result has become the best anchor point for the cosmic distance scale. Eclipsing binary systems composed of late-type stars offer the most precise and accurate way to measure the distance to the Large Magellanic Cloud. Currently the limit of the precision attainable with this technique is about two per cent, and is set by the precision of the existing calibrations of the surface brightness — colour relation. Here we report the calibration of the surface brightness-colour relation with a precision of 0.8 per cent. We use this calibration to determine the geometrical distance to the Large Magellanic Cloud that is precise to 1 per cent based on 20 eclipsing binary systems. The final distane is 49.59 +/- 0.09 (statistical) +/- 0.54 (systematic) kiloparsecs.
In 2013 a team of researchers (including several of the current researchers) published a letter in Nature (2013) which estimated the distance with a precision of two per cent; Arxiv (2013).
Another team of researchers has also posted their recent research on Arxiv (2019) in which they provide a 1% foundation for the determination of the Hubble Constant.
All the links are to abstracts; the full letters to Nature are paywalled, but the Arxiv abstracts have links to PDFs which seem to be complete and accessible.
The Arxiv abstract: In the era of precision cosmology, it is essential to empirically determine the Hubble constant with an accuracy of one per cent or better. At present, the uncertainty on this constant is dominated by the uncertainty in the calibration of the Cepheid period — luminosity relationship (also known as Leavitt Law). The Large Magellanic Cloud has traditionally served as the best galaxy with which to calibrate Cepheid period-luminosity relations, and as a result has become the best anchor point for the cosmic distance scale. Eclipsing binary systems composed of late-type stars offer the most precise and accurate way to measure the distance to the Large Magellanic Cloud. Currently the limit of the precision attainable with this technique is about two per cent, and is set by the precision of the existing calibrations of the surface brightness — colour relation. Here we report the calibration of the surface brightness-colour relation with a precision of 0.8 per cent. We use this calibration to determine the geometrical distance to the Large Magellanic Cloud that is precise to 1 per cent based on 20 eclipsing binary systems. The final distane is 49.59 +/- 0.09 (statistical) +/- 0.54 (systematic) kiloparsecs.
In 2013 a team of researchers (including several of the current researchers) published a letter in Nature (2013) which estimated the distance with a precision of two per cent; Arxiv (2013).
Another team of researchers has also posted their recent research on Arxiv (2019) in which they provide a 1% foundation for the determination of the Hubble Constant.
All the links are to abstracts; the full letters to Nature are paywalled, but the Arxiv abstracts have links to PDFs which seem to be complete and accessible.
Great to see (probable) public funds subsidizing more private academic journals.
Now my navigation system will be able to estimate the arrival time correctly. Why did this take so long?
Hey, those "progressive" fools have been screaming TRUMP COLLUSION!!!! for years now.
When you live in that deep of a FantasyLand, flying to another galaxy is easy!
It will be easier to reach Iscandar.
zero meters.
Did you know, there's two offices on the top floor of Trump tower in NY?
One is Trump's, the other is his hair dresser that does his comb over/weave thing?
What do you mean NO COLLUSION?!?!?!
Did CNN, MSNBC, The New York Times, and The Washingon Post completely IGNORE the lack of evidence and LIE TO US?!?!
For years?!?!
Wow.
So, umm, FAKE NEWS!!!!
is perhaps come on baby...and
Next year, the Chinese plan on landing on the Large Magellanic Cloud and establishing a military base. They will claim it has always been part of their territory.
I went out to *BSD's grave on Decoration Day. The old forgotten cemetery is to be found adjacent to the dark woods beyond the edge of town. There within olfactory distance of the municipal treatment plant you will find *BSD's final resting place.
*BSD's tombstone was shrouded by thick mosses and knots of noxious ivy. A mournful funerary crow sounded the requiem, as I gently pulled aside the tangled twists of thorns, and cleaned the decaying marker the best I could. A suffocating melancholia filled my heart, while I pondered that this indeed was *BSD's figurative charnel house of which so many have plaintively spoken.
Nothing is so pitiful as an untended grave, a loved one now forgotten. The short sad life of this doomed and fated OS makes us realize that there but for the grace of God go all of us.
I planted some wilting marigolds, found discarded in the waste heap behind the caretaker's shack, wishing that by some miracle these fleurs de mort might take root and bring a modicum of cheer to *BSD's God forsaken plot. My fervent hope is that the torpid colored boy, who so carelessly mows the grounds, doesn't slice them down, inadvertently mirroring *BSD's own doomed encounter with death's irresistible scythe.
Funny how things work out. Linux, that brilliant nova stella, now runs the Internet and the world's fastest computers, while *BSD lies moldering within its forgotten crypt. Let the barren silence of *BSD's tomb be a mute reminder that hubris and braggadocio were no defense on that woeful day when the Angel of Death's bleak umbra was cast upon *BSD.
I came here to yabber politics of the Trump prosecution and find this nerd stuff, wth!
(-1: Post disagrees with my already-settled worldview) is not a valid mod option.
1 Parsec = 3.26 light years
1 Kiloparsec = 3262 light years
1 light year = 9.46 trillion kilometers = 5.88 trillion miles
Further than the Basingstoke Roundabout, so stick out your thumb and be prepared for a long trip.
Learning HOW to think is more important than learning WHAT to think.
schedule a bit, huh?
in Kessel Runs ?
Space is Big, Really Big, you won't believe how mindbogglingly huge it is. You might think it is a long way to the Chemist, but that is just peanuts to space, LISTEN! (Apologies to Douglas Adams)
But the size of space, 1% is just a really big number. Lets just say there is a 1% chance you will get hit by a car every day. That means on the average you will be hit by a car 3-4 times every year, for most people that is a lot of times getting hit by a car.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
I guess we are already too advanced on space observation from a distance. Shouldn't those big science heads be put to better use, like figuring out economic and safe ways to us to leave Earth?
I mean, what difference it makes if we know the correct distances? That's the easy part!
Can we give up kiloparsecs already?
Just use SI base units like all other scientists. It's 1.5E21 meters away, or 1.5 Zm
milestones, te7ling
Is it measured from the Earth, from our Sun or from the edge of the Milky Way??
And is it to the closer edge of the Magellanic Cloud or its center or where else??
I always take a telescope with me whenever I visit the southern hemisphere and have spent many evenings (mainly from Australia) exploring the Large Magellanic Cloud. The Tarantula Nebula is one of those must-see items on any such trip.
The Small Magellanic Cloud doesn't have as many goodies but has 47 Tucanae next door which more than makes up for it.
...laura
But whats the margin of error for the spelling in a slashdot article?
How does one measure the distance to a cloud? Are they measuring to one specific star in the cloud? If not... How to measure the distance to something that has no defineable edges or centre?
159 years, in fact, even without re-fuelling time. I guess we'll have to stick to the Spinward Marches a bit longer.