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Don Alexander
2016-Feb-25, 02:38 AM
http://www.nature.com/nature/journal/v530/n7591/full/nature17140.html

I haven't seen a press release just yet, sorry for the direct link to the Nature paper which likely no one can access...

Anyway, for the first time, a Fast Radio Burst has shown a radio afterglow, which led to the localization in an elliptical galaxy without active star-formation at a redshift of about 0.5 (1.8 Gpc, it seems).

- At least some FRBs are cosmological, and therefore very energetic (not GRB level, but still powerful).
- At least some FRBs are NOT associated with massive star-formation, which indicates neutron star mergers as a source.
- Incidentally, this FRB confirmed CMB satellite measurements of the total baryon content of the universe, which might be the most exciting result of all! :rimshot:

We're really living in very exciting times. The Higgs boson, gravitational waves, a possible new planet, and now this stunning result.:D

EDIT: Ah, thank you, astro-ph:

http://arxiv.org/abs/1602.07477
http://arxiv.org/abs/1602.07643

StupendousMan
2016-Feb-25, 02:09 PM
It surprised me at first to read that the FRB was detected back in April, 2015, and localized within a week or two .... yet I hadn't heard anything about it until now. I'm not tied in very closely to the radio community, but, even so, I guess this speaks strongly to the power of Nature and its embargo policy. I wonder what the researchers were thinking in those first few weeks?

"Hey, Fred, look at this -- we've pinned down the location of an FRB!"

"Wow, that's awesome. You have a redshift for the likely host and everything. Boy, this is big news. Should we arrange a press conference? Can I tell my friends?"

"No! Say nothing! The best way to share this discovery is to keep anyone from finding out about it for the next eight months!"

profloater
2016-Feb-25, 03:38 PM
is this related to the 1420 MHz FRB known as the wow signal from 1977 Big Ear at Ohio? ( was in New Scientist 16th jan 2016) / or not?

antoniseb
2016-Feb-25, 06:14 PM
is this related to the 1420 MHz FRB known as the wow signal from 1977 Big Ear at Ohio? ( was in New Scientist 16th jan 2016) / or not?
No ... not. Look up FRB on Wikipedia.

Cougar
2016-Feb-25, 08:39 PM
EDIT: Ah, thank you, astro-ph:

Yes!


These signals are dispersed according to a precise physical law and this dispersion is a key observable quantity which, in tandem with a redshift measurement, can be used for fundamental physical investigations...

...like the cosmic density of ionized baryons, which turns out to be in agreement with the 9-year WMAP observations. Always nice to get totally independent verification!

What, exactly, are they talking about when they say the "signals are dispersed according to a precise physical law"?

And why the restriction "ionized" baryons?

Jens
2016-Feb-25, 11:00 PM
It surprised me at first to read that the FRB was detected back in April, 2015, and localized within a week or two .... yet I hadn't heard anything about it until now. I'm not tied in very closely to the radio community, but, even so, I guess this speaks strongly to the power of Nature and its embargo policy.

Not just Nature. It's the power of the Ingelfinger Rule. Journals threaten to refuse to publish findings that have been published elsewhere or discussed with the media.

Cougar
2016-Feb-25, 11:26 PM
...I guess this speaks strongly to the power of Nature and its embargo policy....

I recall back around new year's, Nature had a column of "predictions" for the new year. Three or four general areas were mentioned for likely developments, one of which was... gravitational waves.

Don Alexander
2016-Feb-26, 12:21 AM
What, exactly, are they talking about when they say the "signals are dispersed according to a precise physical law"?

And why the restriction "ionized" baryons?
I can't actually give you an exact equation but I assume the Dispersion Measure, i.e., how strongly the signal lags over time depending on frequency, is a function of the column density of the IGM, and possibly its ionization state. If you assume a certain column density (e.g., derived from WMAP/Planck observations), you can transform the DM into a distance once you have subtracted the Galactic component and estimated a host component.

Concerning question #2: Neutral matter probably does not interact with radio waves at all unless it gets too thick (read: solid matter). Radio waves will not ionize such matter and the wavelengths are much too large for any scattering effects. I therefore assume neutral matter simply does not contribute to the DM.

StupendousMan
2016-Feb-26, 01:19 AM
Figure 1 from the paper shows the delay in arrival of radio waves as the frequency decreases. One quantitative measure of this delay is the dispersion measure.

21356

Don Alexander
2016-Feb-26, 05:44 PM
"No! Say nothing! The best way to share this discovery is to have it fully peer-reviewed and publish it in a high-impact journal"
FTFY! :P

Seriously, just remember BICEP2... Better to be safe than really, really sorry with these things.

Concerning the "Ingelfinger Rule" - I did not even know that had a name. I was just aware some people refrain from posting papers with high-impact results (submitted to nature/Science) to the arXiv upon submission because they worry the paper might be rejected because "the results would then already be out there."

This is a rather old-fashioned stance, though. I know that at least Nature explicitely allows submitted papers to be put on the arXiv immediately. They don't comment on whether that might entice referees to reject the paper, though...

Posting such a result immediately upon submission does have some advantages, even for the journal. It gets out into the scientific public months earlier, and may garner a bunch of citations already in the pre-print stage.

Additionally, to the best of my knowledge, the number of science journalists who scour arXiv and are actually versed well enough to pick out the "bombs" amid all the "incremental science" seems to be low. So posting such a preprint without any further ado (such as press conferences and filmed visits to famous theoreticians...) will unlikely produce a media blitz.

Though with GWs, we saw how a few Tweets were enough to make it to the front page of big news sites.

StupendousMan
2016-Feb-26, 07:26 PM
I know that at least Nature explicitely allows submitted papers to be put on the arXiv immediately.

Hmmm. That was not my experience with Nature over the last few months, though I was not the first author, and so only saw fragments of the correspondence.

ngc3314
2016-Feb-26, 08:03 PM
We had a near-disaster in this regard some years ago. With a Nature paper in the pipeline, we presented the work at a conference in a poster. A reporter from Science saw it, and was sharp enough to recognize that the HST field we observed had been seen in an earlier press-release image. So he noted down the newly-recognized object IDs and Science published a news note with the identified objects indicated, which we feared would get us thrown out of Nature. (I am now senior enough and open-access-advocate enough to instead have asked to have my name removed from a recent manuscript submitted to one of these oh-so-august journals whose research-paper sections are now, IMO, POTP).

Don Alexander
2016-Feb-26, 10:01 PM
Hmmm. That was not my experience with Nature over the last few months, though I was not the first author, and so only saw fragments of the correspondence.

I have this right from the horse's mouth, I asked Leslie Sage back at the 2008 Nanjing GRB conference. ;)

Additionally, It's stated somewhere on the nature webpage. What you aren't allowed to do is just go to the press and talk to them.

@ngc3314: Smells like SN Refsdal.

Don Alexander
2016-Mar-03, 01:51 AM
Some people have their doubts...

(http://arxiv.org/abs/1602.08434)... while others just post the next Nature paper, showing that some FRBs a FRBR(epeaters)!!! (http://arxiv.org/abs/1603.00581)

Jens
2016-Mar-03, 11:05 AM
I recall back around new year's, Nature had a column of "predictions" for the new year. Three or four general areas were mentioned for likely developments, one of which was... gravitational waves.

Well, rumors might get around, but Nature (along with Science for example) has a strict firewall between the news and journal sections. The reporters definitely are not able to get special information before other journalists.

Jens
2016-Mar-03, 12:39 PM
Additionally, to the best of my knowledge, the number of science journalists who scour arXiv and are actually versed well enough to pick out the "bombs" amid all the "incremental science" seems to be low.

That may be part of it, but not everything. I asked a science journalist about this a few years ago, and he told me that because the preprints have not undergone peer review, he would not report on them. The problem arises when it's a big result and somebody jumps the gun.

01101001
2016-Mar-09, 09:26 AM
Bad Astronomy: FRB UPDATE Part 1: Yeah, So About that Fast Radio Burst… (http://www.slate.com/blogs/bad_astronomy/2016/03/08/extragalactic_fast_radio_burst_identification_ques tioned.html)


But two astronomers have looked at the data and are not convinced an FRB afterglow was actually seen. [...] If the afterglow was not from the FRB, then the distance was not necessarily accurately determined. The FRB may have been in another galaxy entirely, or even in our own!

Stand by for updates.