Pulsar re-detections in PALFA data

Grutte Pier [Wa Oars]~GP500
Grutte Pier [Wa...
Joined: 18 May 09
Posts: 39
Credit: 5,809,371
RAC: 576

How can we see wich pulsar

How can we see wich pulsar are re-detected and wich are new found 1's by Einstein@home.

Otubak
Otubak
Joined: 24 Dec 06
Posts: 19
Credit: 3,527,428
RAC: 0

RE: How can we see wich

Message 93876 in response to message 93875

Quote:
How can we see wich pulsar are re-detected and wich are new found 1's by Einstein@home.


All pulsars listed on that site seem to be re-detections. I'm pretty sure that if there's a newly detected pulsar you'll see an announcement on the e@h homepage.

Grutte Pier [Wa Oars]~GP500
Grutte Pier [Wa...
Joined: 18 May 09
Posts: 39
Credit: 5,809,371
RAC: 576

RE: RE: How can we see

Message 93877 in response to message 93876

Quote:
Quote:
How can we see wich pulsar are re-detected and wich are new found 1's by Einstein@home.

All pulsars listed on that site seem to be re-detections. I'm pretty sure that if there's a newly detected pulsar you'll see an announcement on the e@h homepage.

I realized that afterwards, but i'm only doing this project since 2 months ago.

But it also seems a bit illogical that there are so few re-detections, from the almost 2000 pulsars.

Or has this to do with the filtering of certain parts of the sky a.k.a looking at the clear parts.

tullio
tullio
Joined: 22 Jan 05
Posts: 2,046
Credit: 40,857,335
RAC: 18,138

I believe most of the pulsars

I believe most of the pulsars are in the southern part of the sky, which Arecibo cannot explore. We would need a southern antenna (Parkes?).
Tullio

Mike Hewson
Mike Hewson
Moderator
Joined: 1 Dec 05
Posts: 6,126
Credit: 128,366,463
RAC: 33,129

RE: I realized that

Message 93879 in response to message 93877

Quote:

I realized that afterwards, but i'm only doing this project since 2 months ago.

But it also seems a bit illogical that there are so few re-detections, from the almost 2000 pulsars.

Or has this to do with the filtering of certain parts of the sky a.k.a looking at the clear parts.


Aricebo is pretty unique, in that it doesn't 'steer' like other receivers, being of fixed construction into a mountain. They can do tricks with delays and what-not to look off axis but not too far. Else one waits for the Earth to turn ...... :-)

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

tullio
tullio
Joined: 22 Jan 05
Posts: 2,046
Credit: 40,857,335
RAC: 18,138

Arecibo is the only planetary

Arecibo is the only planetary radar in the world, together with the Goldstone antenna of the NASA Deep Space Network, which is steerable but smaller. Its importance for keeping a watch on Near Earth Objects was highlighted by a recent report of the US National Research Council.
Tullio

Martin Ryba
Martin Ryba
Joined: 9 Apr 09
Posts: 48
Credit: 28,539,896
RAC: 46,968

RE: RE: RE: How can we

Message 93881 in response to message 93877

Quote:
Quote:
Quote:
How can we see wich pulsar are re-detected and wich are new found 1's by Einstein@home.

All pulsars listed on that site seem to be re-detections. I'm pretty sure that if there's a newly detected pulsar you'll see an announcement on the e@h homepage.

I realized that afterwards, but i'm only doing this project since 2 months ago.

But it also seems a bit illogical that there are so few re-detections, from the almost 2000 pulsars.

Or has this to do with the filtering of certain parts of the sky a.k.a looking at the clear parts.

The other factor is there really is "a lot of sky" and Arecibo, being as big and sensitive it is, sees a fairly small patch of it at one time. In fact, one of the big advances of the ALFA feed is that it is an array of 7 feeds (filled hexagon) so one gets seven times the throughput on the telescope. If I recall my numbers right (there's some specifics on the information page that may be more accurate), each beam is a couple arcminutes across (lessee, 200 meter illuminated aperture at 20 cm wavelength means 1000 lambda or 60/1000 = 1/16th degree or 4-ish arcminutes). Roughly square that to get 1/250th of a square degree. There are 40,000 square degrees to the sky, so each beam picks up one *ten-millionth* of the sky. Now, there are more pulsars in the galactic disk than away from it, so the search tends to focus on those more productive areas, though some of the times they may be "piggybacking" on other observations and taking whatever beam locations the telescope gives them.

Several of the rediscoveries are re-detections of pulsars discovered by the simpler analysis of the same data shortly after it was taken. E@H is being used to more finely crunch the same data to look for pulsars that may be in short period binary systems that the standard analysis would have missed. They have a Linux cluster on site to do the basic search processing in near real time.

So, E@H isn't expected to find a whole lot of new pulsars, its objective is to perhaps find one or two (or a dozen, we really have no idea how common they may be) really important pulsars. 95% of the other 2000 are so boring they're observed perhaps once a decade.

"Better is the enemy of the good." - Voltaire (should be memorized by every requirements lead)

Grutte Pier [Wa Oars]~GP500
Grutte Pier [Wa...
Joined: 18 May 09
Posts: 39
Credit: 5,809,371
RAC: 576

So we have more succes by

Message 93882 in response to message 93880

So we have more succes by using the LIGO data then that of arecibo, if we would.
Well we're trying to get Einstein's theories checked, not only to find (double)pulsars

Quote:
Arecibo is the only planetary radar in the world, together with the Goldstone antenna of the NASA Deep Space Network, which is steerable but smaller. Its importance for keeping a watch on Near Earth Objects was highlighted by a recent report of the US National Research Council.
Tullio


There are more, the russians have 1 and in canada is 1.
And probably more, but smaller.

Found an articel about European based (ESA) radar-telescopes.
http://www.esa.int/SPECIALS/Space_Debris/SEMD31WPXPF_2.html

I have seen the Effelsberg 100M directing telescope.
1 of the 2 largest in the world. Massive device :D

page about it from some-one
effelsberg

tullio
tullio
Joined: 22 Jan 05
Posts: 2,046
Credit: 40,857,335
RAC: 18,138

I knew the Russians have a

I knew the Russians have a big phased array radar but since it is military it is difficult to know anything about it. Arecibo has certainly the biggest antenna of all radars. Effelsberg is part of the European eVLBI initiative, which is described in the GARR news (in Italian) at the GARR home page (www.garr.it). GARR is the Italian research network with very high speed connections. I used to be connected to it while working at Trieste Area Science Park. Cheers.
Tullio

Mike Hewson
Mike Hewson
Moderator
Joined: 1 Dec 05
Posts: 6,126
Credit: 128,366,463
RAC: 33,129

RE: So we have more succes

Message 93884 in response to message 93882

Quote:
So we have more succes by using the LIGO data then that of arecibo, if we would.
Well we're trying to get Einstein's theories checked, not only to find (double)pulsars


Yep, plus I reckon there'll be stuff quite unexpected. :-)

Quote:
I have seen the Effelsberg 100M directing telescope.
1 of the 2 largest in the world. Massive device :D


That's a terrific looking gadget, and looks like it has one axis to rotate. The beauty of parabolic dishes!

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.