Bruce AllenForum moderator
Project administrator
Project developer
Project scientist
Joined: Oct 15 04
Posts: 985
ID: 3
Credit: 170,849,008
RAC: 0
We are starting some limited public testing of a new pulsar search on Einstein@Home. This search uses data from the PALFA collaboration, taken at the Arecibo radio observatory. More information about this search will be released in the next few weeks; we'll use this thread (in the Science Message Board area) to provide updates when more information is available, and to answer questions.
Bugs and problems with the new application should be reported in this thread in the Bugs and Problem Reports Message Board area.
____________
... This search uses data from the PALFA collaboration, taken at the Arecibo radio observatory. ...
Thanks for the advanced notice.
Is this search using radio data?
And how does it tie in with the gravitational wave searches? Or is this search something separate?
Is there any overlap with the s@h Astropulse search?
Regards,
Martin
[edit]
For a partial answer to my questions, see: ALFA Pulsar Studies
[/edit]
____________
Powered by Mandriva Linux A user friendly OS!
See the Boinc HELP Wiki
Is this search using radio data?
And how does it tie in with the gravitational wave searches? Or is this search something separate?
Is there any overlap with the s@h Astropulse search?
Yes, this will use radio data from Aricebo. There is a summary .PDF file here for more information. Scroll down to the last few pages for more direct info on the overlap with E@h. It does sound pretty interesting, actually. Good science for physics and space junkies who frequent this project
As to seti astropulse, no, there is no overlap. IIRC, the astropulse project is still looking for ET in just another way.
Seti on these boards is not a good subject to bring up: many consider it to be outside the bounds of serious scientific inquiry.
____________
(Click for detailed stats)
Without SETI there would not have been BOINC. Even IBM has converted its World Community Grid to BOINC. Only Folding@home is standing away from BOINC, but this is not surprising given the rivalry existing between Berkeley U.and Stanford U. Although I have a degree in theoretical physics I am not ashamed to contribute a part of my processing time to SETI in both MB and Astropulse versions. You can always learn something from Berkeley.
Tullio
____________
As to seti astropulse, no, there is no overlap. IIRC, the astropulse project is still looking for ET in just another way.
UC Berkeley have prepared a technical paper on radio pulse searches, including Astropulse - intended for publication in Acta Astronautica. I hope you would take the time to at least glance at section 4 of http://setiathome.berkeley.edu/sah_papers/berkeley_pulse_search_paper_nov_2008.pdf - you may find that there is more in common with 'serious' pulsar searches than you at first thought.
As to seti astropulse, no, there is no overlap. IIRC, the astropulse project is still looking for ET in just another way.
UC Berkeley have prepared a technical paper on radio pulse searches, including Astropulse - intended for publication in Acta Astronautica. I hope you would take the time to at least glance at section 4 of http://setiathome.berkeley.edu/sah_papers/berkeley_pulse_search_paper_nov_2008.pdf - you may find that there is more in common with 'serious' pulsar searches than you at first thought.
I hope ancient 'rivalry' is not going to cloud the search...
What is it that e@h will be doing that is different or more comprehensive?
Keep searchin',
Martin
____________
Powered by Mandriva Linux A user friendly OS!
See the Boinc HELP Wiki
... There is a summary .PDF file here for more information. ...
(Last slide: ) The Pulsar Timing Array looks rather interesting for gravitational wave detection!
Keep searchin',
Martin
(As mentioned over on s@h.)
____________
Powered by Mandriva Linux A user friendly OS!
See the Boinc HELP Wiki
Seti on these boards is not a good subject to bring up: many consider it to be outside the bounds of serious scientific inquiry.
I'd reckon it quite legitimate to discuss the science here despite how 'serious', or not, people think it is. I'm not aware of any negatives on the science of SETI, though perhaps some might confuse/confound the science with the social/philosophical/religious etc issues.
Of course we have SETI to thank for the whole distributed computing thrust in recent times, and there is considerable commonality with E@H in particular - needle in the haystack stuff.
I reckon it's a brilliant move to 'fold in' other targets of enquiry. It enhances the science value obtained from the volunteer base, and hopefully enthuses the crunchers too!! With fiscal issues more prominent these days, and likely science funding particularly, it looks to be a pragmatic way to achieve some hefty intellectual goals. :-)
Cheers, Mike.
____________
"I have made this letter longer than usual, because I lack the time to make it short." - Blaise Pascal
BikemanForum moderator
Volunteer developer
Joined: Aug 28 06
Posts: 2056
ID: 210833
Credit: 5,079,839
RAC: 9,661
Hi!
AFAIK, the use of pulsars as "arms" of a GW detector of monumental size is by far not the only motivation for this search. The E@H search explicitly targets pulsars in binary systems, which have been used in the past to test many predictions of general relativity.
CU
Bikeman
____________
Astropulse has had its teething troubles but now it seems OK. I have restarted it on my SETI account. The paper referred to by Richard Haselgrove can be found also on the SETI home page.
Tullio
____________
One thing I always like liked about SETI was it's graphics. I believe it had a graphical representation of "fast Fourier transform" analysis of radio signals.
I wonder if your pulsar search uses fast Fourier transforms, and if the SETI screensaver is open source? hint hint
I tend to get bored by the abstract activities of crunching WU's. Intellectually I have a general understanding of what I am doing. However; I find an active graphic that provides immediate direct knowledge of the work my computer is doing - to be emotionally satisfying.
Every once in a while; watching an animated graphic that demonstrates my computer doing useful work, even if I happen to be taking a break, is a pleasant experience. I have found that I tend to stick with projects that have such graphics. However; there is always an exception, and for me it was SETI!!
BikemanForum moderator
Volunteer developer
Joined: Aug 28 06
Posts: 2056
ID: 210833
Credit: 5,079,839
RAC: 9,661
There is a thread in the Cruncher's Corner section about writing your own screensaver for Einstein@Home (afaik nobody has yet actually done an alternative screensaver/graphics window for E@H). I'm sure once the pulsar search is in "production", Bernd will be happy to release the source code for the pulsar search screensaver as well.
CU
Bikeman
____________
There is a thread in the Cruncher's Corner section about writing your own screensaver for Einstein@Home
I am not a programmer. I did write some short programs in Basic - back when I had a Radio Shack color computer that used a cassette tape recorder as long term storage. Long long time ago!
I did learn to use TopCatLite v3.1 to create gifs showing multiple WU's. I will try and place those on a more appropriate thread.
HERE
Is there a way for us that is using app_info to run beta 6.10 for win to get the files to run both. I´m wondering because I saw the files listed in current version section (3.02 for win).
Is there a way for us that is using app_info to run beta 6.10 for win to get the files to run both. I´m wondering because I saw the files listed in current version section (3.02 for win).
You could manually download the einsteinbinary_ABP1_3.02* files from http://einstein.phys.uwm.edu/download/ and add a section for app einsteinbinary_ABP1 to the app_info.xml. However I doubt that this would make much sense right now as we are not issuing any ABP1 work in the next weeks and furthermore you'd miss updates to the einsteinbinary application.
Better help us test the 6.10 Windows Beta App so we can make it official and then switch back to the "official" path.
BM
Is there a way for us that is using app_info to run beta 6.10 for win to get the files to run both. I´m wondering because I saw the files listed in current version section (3.02 for win).
You could manually download the einsteinbinary_ABP1_3.02* files from http://einstein.phys.uwm.edu/download/ and add a section for app einsteinbinary_ABP1 to the app_info.xml. However I doubt that this would make much sense right now as we are not issuing any ABP1 work in the next weeks and furthermore you'd miss updates to the einsteinbinary application.
Better help us test the 6.10 Windows Beta App so we can make it official and then switch back to the "official" path.
BM
Ok have downloaded them just in case I should need them. I´m allready running beta 6.10 so I have to keep track of update myself.
Seti on these boards is not a good subject to bring up: many consider it to be outside the bounds of serious scientific inquiry.
I'd reckon it quite legitimate to discuss the science here despite how 'serious', or not, people think it is. I'm not aware of any negatives on the science of SETI, though perhaps some might confuse/confound the science with the social/philosophical/religious etc issues.
Of course we have SETI to thank for the whole distributed computing thrust in recent times, and there is considerable commonality with E@H in particular - needle in the haystack stuff.
I reckon it's a brilliant move to 'fold in' other targets of enquiry. It enhances the science value obtained from the volunteer base, and hopefully enthuses the crunchers too!! With fiscal issues more prominent these days, and likely science funding particularly, it looks to be a pragmatic way to achieve some hefty intellectual goals. :-)
Cheers, Mike.
Perhaps the idea will be to eventually have just one Boinc project where you check boxes to say what sort of WUs you'd like to work on. It would make it easier to keep up with what is out there. I've missed some projects that I found interesting simply because there are so many out there now.
Of course Einstein always has and always will be my favourite.
____________
Physics is for gurls!
Perhaps the idea will be to eventually have just one Boinc project where you check boxes to say what sort of WUs you'd like to work on. It would make it easier to keep up with what is out there...
Isn't that what we've already got with the two account managers?
BAM and GridRepublic?
Happy crunchin',
Martin
____________
Powered by Mandriva Linux A user friendly OS!
See the Boinc HELP Wiki
BikemanForum moderator
Volunteer developer
Joined: Aug 28 06
Posts: 2056
ID: 210833
Credit: 5,079,839
RAC: 9,661
For those with some physics background, there's a nice poster explaining some details about the planned search here
Bikeman
____________
Any chance to have an estimated % of work completed and work still remaining for the PALFA search, like we have for the S5R5 search on the einstein status page?
____________
So far:
http://en.wikipedia.org/wiki/Einstein@Home
does not cover any aspect of the Arecibo search at all.
There is no real site web text to contribute to Wikipedia, as far as I can tell.
The forum posts are at best fragmentary.
____________
Any chance to have an estimated % of work completed and work still remaining for the PALFA search, like we have for the S5R5 search on the einstein status page?
No.
The GW search is organized in "runs" that are performed one at a time (neglecting transitions), which have a number of workunits that is fixed at the beginning of the run.
The PALFA search is a more or less constant stream of workunits, it will end when ARECIBO stops taking data (probably we'll then even dig out data from before the start of our search that is still usable). In a sense this search never ends.
BM
Any chance to have an estimated % of work completed and work still remaining for the PALFA search
No. BM
What about some statistics about what percentage of the data we are able to analyze. Is the network fast enough to analyze all the data real time? Or is half of it thrown out?
Is the data from arecibo still coming in? The seti@home receiver is down.
____________
Currently Einstein@home is processing the ARECIBO data slower than we get it, so there's plenty of data left to process. We're working on speeding up the search, but currently we are far from real-time.
BM
Given that the binary pulsar searching is letting data stack up, is there a processing thread that close to keeps up with the data that searches for non-binary (or long binary period) millisecond pulsars? I know in the past things like the NCSA centers (remember those?) were used for this crunching. Picking off some new "low hanging fruit" would certainly make the volunteers happy. I know this implies a new processing thread (and therefore a lot of work), but given the interest in a MSP timing array, finding a few more of those would be a nice benefit.
Or, does the pre-processing thread take care of that? As I understand it, the data for the binary search is already de-dispersed for a target DM. All that's left after that is a (big) FFT and harmonic peak search to find lone pulsars.
Marty
____________
"Better is the enemy of the good." - Voltaire (should be memorized by every requirements lead)
Which is the meaning of the Arecibo Power Spectrum which appears at top right in the graphics? It seems to differ from unit to unit.
Tullio
____________
Which is the meaning of the Arecibo Power Spectrum which appears at top right in the graphics? It seems to differ from unit to unit.
Tullio
I don't have authoritative word, but I would presume it's a plot of total energy in the band across various frequency bins. So, high bins are bad in that they generally imply some form of interference in the band (e.g., cheap radios or cell phones that emit out of band, or these days laptop computers are a common culprit given the clock frequencies of these babies exceed 1 GHz).
If you look at the files that get downloaded with each WU, you may see a zaplist_xxx.txt file. Those identify specific frequency bins that were excluded because of too much terrestrial interference.
____________
"Better is the enemy of the good." - Voltaire (should be memorized by every requirements lead)
Which is the meaning of the Arecibo Power Spectrum which appears at top right in the graphics? It seems to differ from unit to unit.
This power spectrum is the result of the computation your machine has done and is refreshed with each new orbital template. It shows an |FFT|^2 of the demodulated time series over the range of 0 Hz to 240 Hz in 40 bins. (Remember that one of the steps in the calculations on your machine is the conversion of the time series into pulsar frame time assuming different binary orbits and orbital orientations to take out Doppler modulation - this step is called demodulation. Check also this info page).
If there's a strong pulsar in the data set it will show up as a peak in at least one of the bins at its spin frequency. There are however some human-made interferences (e.g. radar) that will look similar, so not every peak in this diagram is a pulsar.
By closely looking at the power spectrum one can actually tell how fast the pulsar in the data set is spinning and (in combination with the template information in the lower right corner) how the orbit might look like.
____________
Thanks to Martin and Benjamin. Most of the times I see the leftmost and second leftmost bin higher and whiter, so I guess they are interference.
____________
the leftmost and second leftmost bin higher and whiter,
Yes, there is sometimes the radar at 1/12 Hz = 0.083333 Hz, which has many higher harmonics as well. That would show up in these bins.
There are, however, low frequency pulsars as well: re-discoveries all of which would be in the first bins.
____________
the leftmost and second leftmost bin higher and whiter,
Yes, there is sometimes the radar at 1/12 Hz = 0.083333 Hz, which has many higher harmonics as well. That would show up in these bins.
There are, however, low frequency pulsars as well: re-discoveries all of which would be in the first bins.
Ahh, I gladly stand corrected on the nature of the "Power Spectrum" plot. So it's the "pulsar-like signals" power spectrum. Nice! The re-discovery of the 2.1 ms pulsar I presume would have shown up in one of the more rightward bins since that's over 400 Hz...in fact it may have been right off that scale! The fastest known pulsars spin at about 650 Hz. If I recall my pulsar statistics off the top of my head, more than 90% of pulsars spin in the 0.3 to 5 Hz range. These are the "boring" pulsars few researchers spend much time on. The nearest ones of this ilk were discovered first. Picture Jocelyn Bell, or soon after the Arecibo operators, poring over a strip chart analog recording looking for periodic bumps in the trace. Now we've got thousands of computers doing it.
____________
"Better is the enemy of the good." - Voltaire (should be memorized by every requirements lead)
Picture Jocelyn Bell, or soon after the Arecibo operators, poring over a strip chart analog recording looking for periodic bumps in the trace. Now we've got thousands of computers doing it.
Yes! How many meters per second would the paper chart have to run at to be able to get a decent human eyeball resolution of the fastest known pulsar, say ~ 700+ Hz ?
If you want a pulse gap of 1cm, say, then that's seven meters per second. If you wanted the pulse width to be 1cm, so as to discern features ( assume width is 0.1 of the period ) then that's 70 meters/sec **.
Imagine trying to keep such a record coherent over years to get spindowns and what not. A bit like the WW2 code crackers before the 'bombes'. You couldn't even conceive of a project like LIGO without digital computers. It would have to be realtime analog computing at best, or maybe some hope with magnetic tape storage.
Cheers, Mike.
( edit ) I think you can do analog FFT circuits .....
( edit ) ** Hey, that's ~ 250 km/hour !! :-)
( edit ) OK. Getting silly now. Take the Hulse-Taylor pulsar, found in 1974. About 17 Hz. Follow to present day ~ 35 years. Total length of paper tape at 1cm per pulse width = 35 * 365 * 24 * 3600 * 17 * 10 = 187639200 km = 187639200/149598000 ~ one and one quarter of the Earth-Sun distance. About 19 billion rotations of the star. Try not dropping a count/carry during that! :-)
____________
"I have made this letter longer than usual, because I lack the time to make it short." - Blaise Pascal
( edit ) OK. Getting silly now. Take the Hulse-Taylor pulsar, found in 1974. About 17 Hz. Follow to present day ~ 35 years. Total length of paper tape at 1cm per pulse width = 35 * 365 * 24 * 3600 * 17 * 10 = 187639200 km = 187639200/149598000 ~ one and one quarter of the Earth-Sun distance. About 19 billion rotations of the star. Try not dropping a count/carry during that! :-)
Less silly, dusting off my thesis, I stated that the observations of PSR B1937+21 (J1939+21) that we had collected from mid-1984 to the time of my thesis in early 1991 spanned exactly 130,476,403,197 rotations of the pulsar. Given that number of significant digits, the TEMPO timing software has to take care to avoid rounding errors from even double precision floating point calculations, since the TOA (pulse phase) measurements are good to better than 1/1000 of a period. There have now been some more significant gaps in the collection of timing data on that pulsar, but I would think we should still be capable of resolving the integer rotation number to present. If so, data spanning 1984 to now (25 years * 3e7 seconds/year * 642 rev/sec) = 506 billion revolutions.
B1937+21's signal was too weak to see on a strip chart (or if you used enough bandwidth the signal was smeared by dispersion). I do remember the excitement of hooking analog output from my coherent dedisperser circuit to an analog signal averager at Arecibo and watching the pulses come out of the noise in a few seconds. Occasional giant pulses would pop above the noise floor though, especially down at 430 MHz. I remember having a spectrum analyzer listening to the live signal from another nearby pulsar (0950?) with a roughly quarter second period and taking the "video out" directly to a speaker: pop, pop, pop, bang!, pop, pop, bang!, pop, pop,...
Too bad the LIGO gang can't have that kind of fun with their instrument. The Arecibo control room is a fun place to hang out at oh-dark-thirty in the morning.
____________
"Better is the enemy of the good." - Voltaire (should be memorized by every requirements lead)
B1937+21's signal was too weak to see on a strip chart
You would have had fun trying to crunch all of that data on the
486 DX 2’s that were ‘state of the art’ in 1991 :-)
Bill
...If so, data spanning 1984 to now (25 years * 3e7 seconds/year * 642 rev/sec) = 506 billion revolutions...
Which kind of billion? (I'm just too lazy to count the zeros myself ;-)
Gruß,
Gundolf
...If so, data spanning 1984 to now (25 years * 3e7 seconds/year * 642 rev/sec) = 506 billion revolutions...
Which kind of billion? (I'm just too lazy to count the zeros myself ;-)
That'd be the 1000 million type of billion = 10^9
I think the original British billion was a million of millions = 10^12 which we now call a trillion. I think the British did call the 10^9 type of billion a 'milliard' ???
Too bad the LIGO gang can't have that kind of fun with their instrument. The Arecibo control room is a fun place to hang out at oh-dark-thirty in the morning.
Actually they do, a few years ago I saw a Hanford ilog entry by Peter Saulson and on a night shift too. He'd hooked up an audio amp/stereo to something derived from the differential arm error signal ( effectively the interferometer dark port output ) and described for us all sorts of creaks, groans and stuff. No gravity waves per se but the movement of the instrument was made audible. Now I wonder if we can con them to stream it live ..... :-)
Cheers, Mike.
( edit ) Livingston iLog actually
Topic: general Author: Peter Saulson
Sun Jan 4 16:35:59 2004 UTC
Listening to the ifo output on the loudspeaker in the control room is a lot of fun. The sound reminds me of a dog that is dreaming it is chasing something, breathing dramatically and irregularly as it "runs". It is a high pitched wheezing sound, broad-band high frequency noise modulated on time scales of order a second (just as one sees in graphs of the AS_Q time series, no surprise.)
What is obvious as one does this is that the loud moments correspond to times when the output port is momentarily bright. The AS_DC-by-eye and the sound also have a flutter (is it 10/sec?) What causes that?
What is completely non-obvious is why the histogram of AS_Q should grow broad wings when the AS_DC excursions grow large. (Why shouldn't the width of the histogram just be modulated?) The correlation of glitches with times when AS_DC was large was the pattern that we saw in S2 burst analysis; evidently, we'll find the same pattern in S3. It would be nice to understand (and even better to fix) the mechanism.
- Peter Saulson
Topic: SciMon Author: Peter Saulson
Mon Jan 2 22:05:06 2006 UTC
Day Shift SciMon summary
Operators: Harry Overmeir until noon, then Danny Sellers
SciMon: Peter Saulson
A shift during which it was a struggle to get locked and to stay in lock. The cause was high seismic noise in the band below the microseism, caused by winds of up to 15 mph, along with surprisingly high noise in the anthropogenic bands (given that there was no construction work going on today.) The result was only a few sub-hour science mode segments. While in lock, one could see the beam spots bouncing around, and a fair amount of non-stationary noise in the sub-100 Hz band. A few times, there were audible "thumps" in the loudspeaker playing the ifo output; those corresponded with rather gigantic amounts of excess noise, and to minutes where SenseMon showed much lower range. (Two of these occurred in the last several minutes of the science segment that included 1400 Central = 2000 UTC.)
Topic: SciMon Author: Peter Saulson
Sun Feb 6 06:00:40 2005 UTC
Evening Shift Summary
SciMons: Peter Saulson (expert), Andy Rodriguez (trainee)
Operators: Tom Evans until 10 p.m., Gary Traylor thereafter
A quiet shift of the finest kind. The ifo has been in lock for over 10 hours by now, with low noise and otherwise good behavior, too.
......
Tom's Operations Log entry mentions loud thumps that we heard over the loudspeaker near 2304 and 2305 UT. It would be nice to find them with some of the Burst Search Event Trigger Generators. Gary's log will mention another at 0459 UT. Let's find this one, too!
......
- Peter Saulson
____________
"I have made this letter longer than usual, because I lack the time to make it short." - Blaise Pascal
I think the British did call the 10^9 type of billion a 'milliard' ???
Cheers, Mike.
We call it a miliardo, though many call it a bilione, by the usual Italian habit of mistranslating English words.
Tullio
____________
Less silly, dusting off my thesis, I stated that the observations of PSR B1937+21 (J1939+21) that we had collected from mid-1984 to the time of my thesis in early 1991 spanned exactly 130,476,403,197 rotations of the pulsar. Given that number of significant digits, the TEMPO timing software has to take care to avoid rounding errors from even double precision floating point calculations, since the TOA (pulse phase) measurements are good to better than 1/1000 of a period. There have now been some more significant gaps in the collection of timing data on that pulsar, but I would think we should still be capable of resolving the integer rotation number to present. If so, data spanning 1984 to now (25 years * 3e7 seconds/year * 642 rev/sec) = 506 billion revolutions.
Wow, good job! My silliness retracted post-haste. That's a bit like asking if Avagadro's number is a prime! Or if you've counted all the rocks in Wales ..... :-)
Cheers, Mike.
____________
"I have made this letter longer than usual, because I lack the time to make it short." - Blaise Pascal
I think the original British billion was a million of millions = 10^12 which we now call a trillion. I think the British did call the 10^9 type of billion a 'milliard' ???
Correct, however the word has fallen in disuse. I think they just say 'a thousand million/billion/trillion' instead nowadays, and a billion is still 10^12. The words are still in use in Dutch, however. The discrepancy between the British and the American definitions is very aggravating, because you can never trust anything you read unless someone states up front what they mean.
B1937+21's signal was too weak to see on a strip chart
You would have had fun trying to crunch all of that data on the
486 DX 2’s that were ‘state of the art’ in 1991 :-)
Bill
Ah, now I'm getting into nostalgia. Our "Mark III" system had a couple custom-built ISA cards (full length *wire wrap* boards!) with various MSI and LSI logic chips on them (e.g., separate multipliers and adders). The PC that did the crunching and real time control was a 486 DX2, running DOS with some high memory support. With the FORTRAN77 compiler we had (Lahey), we did have to keep our executable under 600 kB including all arrays (we put COMMAND.COM in high memory). Remember Bill Gates' classic comment that 640 kB should be all anyone would need?
One time, when one of us (not me!) was trying to debug a board, he stuck a voltmeter probe into the ISA connector on the the mother board to make sure the 12V supply was good. Unfortunately, he shorted that 12V over to an address line on the other side of the socket. Pop! went one of the glue chips on the motherboard. There was a crater in the middle where the silicon used to be! So much for that PC!
We did our pulsar survey processing on the "big iron" at a couple of the NSCA supercomputers.
____________
"Better is the enemy of the good." - Voltaire (should be memorized by every requirements lead)