Astronomers find unexpected, dust-obscured star formation in distant galaxy

Astronomers find unexpected, dust-obscured star formation in distant galaxy
Hubble Space Telescope image of the field containing a massive foreground galaxy cluster, MACSJ0717.5+3745. Pope and colleagues' dusty galaxy is denoted by the red squares which show three images of the same gravitationally lensed background galaxy. A zoom in of each multiple image is shown in the right panels.  Credit: Original image by NASA, European Space Agency and the Hubble Space Telescope Frontier Fields team. Color composite from Wikimedia Commons/Judy Schmidt; annotations and zoom panels added by A. Montana.

Pushing the limits of the largest single-aperture millimeter telescope in the world, and coupling it with gravitational lensing, University of Massachusetts Amherst astronomer Alexandra Pope and colleagues report that they have detected a surprising rate of star formation, four times higher than previously detected, in a dust-obscured galaxy behind a Frontier Fields cluster.

As Pope explains, "This very distant, relatively typical galaxy is known to us, and we knew it was forming , but we had no idea what its real rate was because there is so much dust surrounding it. Previous observations couldn't reach past that. Finding out that 75 percent of its star formation was obscured by dust is remarkable and intriguing. These observations clearly show that we have more to learn."

She adds, "Historians want to know how civilizations were built up, and we astronomers want to know where and how the elements in the universe were formed and where everything is made of, came from." The study is accepted for publication in The Astrophysical Journal.

The new tool that has made such revelations possible is the 50-meter Large Millimeter Telescope (LMT) which has been observing as a 32-meter telescope located on an extinct volcano in central Mexico in "early science mode" since 2013. Operated jointly by UMass Amherst and Mexico's Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), it offers astonishing new power to peer into dusty , the astrophysicist says.

Pope, an expert at analyzing how dust masks star formation, says tracing dust-obscured galaxies at early epochs offers good signposts for understanding how the universe became enriched with metals over time. "We know at the basic level that metals are formed in stars, but the rate of buildup over cosmic time we don't know," she points out. "We know what we see today but we don't know how it came about, and we want to fill in that picture."

Overall, she and colleagues write, "This remarkable lower-mass galaxy showing signs of both low metallicity and high dust content may challenge our picture of dust production in the early universe."

Before the AzTEC camera on the LMT took observations of this galaxy, astronomers relied on Hubble Space Telescope images to study star formation, Pope says. But most star formation is obscured by dust, so the Hubble images could not make a complete census of the buildup of stars in this galaxy. "Previous millimeter observations have been limited to the most extreme dusty galaxies. With this study, we have detected a surprisingly high rate of dust-obscured star formation in a typical galaxy in the early universe."

With , researchers use a foreground mass - another galaxy or a galaxy cluster - as a lens. As light from very distant, background galaxies passes through, it is magnified. "This technique offers a way to see things that are much fainter than your telescope can see," she notes. As traced in Hubble images, the lensed galaxy they studied in the Frontier Fields cluster showed it forming only about four solar masses of new stars per year, which is a "fairly typical" observation and unsurprising to astronomers today, Pope says. "But then the LMT observations revealed another 15 solar masses per year, which means we had been missing about three-quarters of the star formation going on."

She adds, "We are not yet at the level of detecting all of the star formation going on, but we are getting better. One of the big goals for us is to push observations at longer wavelengths and to trace these very dusty galaxies at early epochs. We are pushing observations in this direction and the fact that Hubble found only one quarter of the star formation in this distant normal galaxy is a huge motivation for doing a lot more studies like this."

As early as next year, Pope and her colleague Grant Wilson will install on the LMT a new state-of-the-art imaging system he is building, dubbed TolTEC. It will offer mapping speed 100 times faster than the LMT's current capability making it the fastest millimeter-wavelength polarimetric camera on Earth for conducting deep surveys of the universe, Wilson says. It should allow astronomers to create a census of star-forming galaxies, and observations that require five years to complete today will be done in a little over one week.

Pope says, "Currently, our census of dust-obscured star formation activity in galaxies is severely incomplete, especially in the distant universe. With TolTEC on the LMT, we will be able to make a complete census of dust-obscured star formation activity in galaxies over 13 billion years of cosmic time.


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More information: Early Science with the Large Millimeter Telescope: Detection of dust emission in multiple images of a normal galaxy at z>4 lensed by a Frontier Fields cluster, arxiv.org/abs/1703.04535
Journal information: Astrophysical Journal

Citation: Astronomers find unexpected, dust-obscured star formation in distant galaxy (2017, March 23) retrieved 18 July 2019 from https://phys.org/news/2017-03-astronomers-unexpected-dust-obscured-star-formation.html
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Mar 23, 2017
OK, now I am totally baffled.
Here this researcher is talking about star formation like it was a very common and highly regular occurrence with all astronomers and other physicists observing such things happening ALLLLLL THE TIME! Like star formation and actual observation is OLLLLD hat and pretty boring.

Yet, from what I know - I might be terribly ill informed according to this article - there has been absolutely ZERO real observations of ANY star forming whatsoever. If anyone has a fully documented and verified record that shows that beautiful event, please let me know. I'd like to know who won the Nobel Prize for that observation.

So I must ask in my ignorance: Is she really observing stars forming from dust or is she observing stars that get revealed by clearing the dust or penetrating the dust?

She seems so incredibly confident that those stars are forming from dust all by themselves that there is no room for doubt whatsoever. I'm dumbfounded.

RNP
Mar 23, 2017
@FredJose
...there has been absolutely ZERO real observations of ANY star forming whatsoever.


Of course we have not actually observed any individual star form! The timescales involved span millions of years, so such an observation is physically impossible.

I think you must most certainly know this, but are just being obtuse. If not, go and learn some astrophysics before you post here again.

Regardless of concerns regarding your intentions, let me answer by saying that what we CAN observe is literally MILLIONS of individual stars, all at different stages of their formation/evolution. So, just like using a large number of photos of different people at different ages to build a good model of how people grow and evolve, we can do the same thing with observations of star formation.

Mar 23, 2017
I think you must most certainly know this, but are just being obtuse. If not, go and learn some astrophysics before you post here again.


What we really know is that you know a great deal about asstro-physics & very little about "astrophysics". Of course what could the casual reader expect from someone who has admitted his real job is merely that of a journalist, and probably a fake one at that.

Mar 24, 2017
@Benni,
RNP is quite likely a NSA persona, here to garner credibility, in order to influence the unsuspecting and discount those who get close to the real insights. In short, just a spook. Take a look at who owns this site. Clearly it is an intelligence community asset. With recent surveillance disclosures, should anyone really wonder otherwise??

So if not RNP, then watch out for others. They are numerous.

Dust in the early universe? Say it ain't so!

Mar 26, 2017
@Benni,
RNP is quite likely a NSA persona, here to garner credibility, in order to influence the unsuspecting and discount those who get close to the real insights. In short, just a spook. Take a look at who owns this site. Clearly it is an intelligence community asset. With recent surveillance disclosures, should anyone really wonder otherwise??


I understand whereof you speak. RNP has repeatedly prodded me to link to specific websites after I shoot down another of his dumb ideas.

The very last exchange I had with RNP was a couple days ago, after he'd put up one of his favorite video links, was to ask me why I hadn't yet clicked on it, I in turn asked him how he knows I didn't.........he has yet to respond.

So if not RNP, then watch out for others. They are numerous.
Oh sure, I know......they'll just show up here out of the cold clear blue pretending to be your friend when they are anything but.


Mar 26, 2017
@Benni,
RNP is quite likely a NSA persona, here to garner credibility, in order to influence the unsuspecting and discount those who get close to the real insights. In short, just a spook.


Tux, here is precisely the problem with RNP, he's far too polished with his semantics. Someone as well polished at his level of writing skill is not someone who is a science professional. He's definitely a Pop-Sci Culture guy on a mission, whatever that mission is.

If he's an NSA, it's been fun cornering him on just the most simple aspects of General Relativity, such as application of the Inverse Square Law which he never heard of until he started having exchanges with me. He doesn't realize how his duck, dodge, and weave responses, to what should be routine answers, are dead giveaways to his ulterior motives, and then he puts up links to laughable videos & wonders why I never click on them.........so how does he know I don't?

RNP
Mar 26, 2017
@Benni
...here is precisely the problem with RNP, he's far too polished with his semantics. Someone as well polished at his level of writing skill is not someone who is a science professional.

If he's an NSA, ...


WOW! Thank you very much for the compliment! It is not the sort of compliment we science professionals often receive, so it is very special to me.

But wait... Am I getting confused? Have I worked in science all my life as my memories suggest, or am I some kind of progammed NSA spy? I wish now that I had believed you when you tried convince me that I was a journalist.

Ooooooh, I've just realized.... Perhaps I a journalist working for the NSA! Thank god for that, for a moment there I didn't know who I was!!!!

Mar 26, 2017
Thank god for that, for a moment there I didn't know who I was!!!!
..........now that you know, you can come in from wandering out in the deep weeds with the many other journalists who imagine they are such an important segment of critical thought.


Mar 26, 2017
let me answer by saying that what we CAN observe is literally MILLIONS of individual stars, all at different stages of their formation/evolution.

You realize that FredJose:
a) doesn't know that the world evolution means something different in the biological and astronomy contexts
and
b) that he doesn't know the meaning of the owrd in eiither case?

He repeatedly convoluted darwinism with stellar evolution and biological evolution with abiogenesis. Don't even bother. If he's not prepared to learn the meaning of words he's not here to be educated. He's here to toot his fanatic-religion horn and nothing else.

RNP
Mar 26, 2017
@Benni
Does it not embarrass you that your posts are largely fantasy and everybody knows it, *including* you?

Does it not embarrass you that you that nearly everything scientific you post here is nonsense, and nearly everybody knows it, *except* you?

Does it not embarrass you that nearly everybody that posts on this site thinks that you are a.... what was the word used... cunf was it?

You need to lose the pre-adolescent attitude, and methods of argument, and learn to discuss things like an adult if you do not want to continue making a fool of yourself and perhaps learn something.

Mar 26, 2017
Does it not embarrass you that nearly everybody that posts on this site thinks that you are a.... what was the word used... cunf was it?


You don't even remember the spelling of the word in question from your own post? No wonder you have such a problem comprehending General Relativity & application of the Inverse Square Law. Yeah, anyone who applies the ISL from the center of a mass like you do, is indeed someone who has a problem with any basic level of physics.

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