Update on Pulsar timing for GLAST with the Nançay Radio telescope. David Smith et al CENBG/In2p3/CNRS Bordeaux, France. Topics. Big Nançay time request submitted today, see form-NRT-Avril2006_HE4.pdf at http://www.cenbg.in2p3.fr/ftp/astropart/Smith/Pulsars/
Update on Pulsar timing for GLAST with the Nançay Radio telescope
David Smith et al
Nançay time request due today
The ~140 pulsars
How we calculate telescope time
Best of 4 observations. Ismael trying to improve.
Roger’s test pulsars
From rwr@astro.Stanford.EDU Tue Jan 31 20:00:23 2006
To: D.A. Smith <email@example.com>Subject: some glast pulsars
Hi David -- as requested, here are a few pulsars that you candiscuss in your upcoming meeting with Ismael. I will describesome of my thinking in ranking things on the 21st. But here are10 PSR worth discussing, all above DEC -35. Note -- many of theseare presently being timed, although it is not clear that the timingis adequate or will continue during GLAST. You might want to avoid competing in the Arecibo DEC range (0-38), as well:
Ridiclously difficult, but important:
J1833-1034 0.08767 0.07
J1930+1852 0.004619 0.06
J2021+3651 0.0001662 0.1
J1946+2611 5.776e-05 0.06
Not so hard, but likely interesting
J1747-2958 0.008501 0.25
J2229+6114 0.00108 0.25
J1815-1738 0.0002536 0.25
J1913+0832 0.0001506 0.6
J1734-3333 0.000144 0.5
J1735-3258 4.161e-05 0.46
Anyway, something to discuss, although certainly notan exhaustive list. Let me know what Ismael thinks... -- Roger
Roger classed this as “ridiculously hard” but it is easily detectable. ATNF doesn’t have S1400 for this one, so RWR extrapolates from 400 MHz assuming a 2.5 spectral index, apparently an underestimate in this case. Also, ATNF doesn’t have W50, so RWR takes W/P = 10% but here it’s even narrower.
2 minutes each
One neutron star rotation
Ismael is (understandably!) proud that Nançay achieves 0.6/435 = 1 mP timing in about 2 minutes.
Nota bene: a few points over a few months to get P and Pdot.
A 60 mJy ms pulsar
2 minute slices
This is also one of the
10 HESS targets.
One neutron star rotation
This one has S1400 1.4 mJy but the timing parameters in the literature are a bit off.
Ismael & Gilles load the ephemeredes into the BON de-dispersor front-end, which does heavy processing of terabytes of data. The raw data is lost. From this detection, refine the parameters, and iterate. This is part of why it’s good to get a head-start.
Ismael made this slide for the January workshop. Denis and I have fiddled with his list, to demonstrate RWR’s (W/P)1.5/S_1400 law. Again, more of a guideline than a hard & fast rule.
Telescope time, cont’d
We’d like to write the same article, next year…
… but they took >3 years!
“Visits per Year” not an exact science
In consequence, at Nançay measurements of large numbers of “our” pulsars will allow us to nail down just how often we’ll need to come back to any given pulsar, in addition to knowing how long to dwell on any single pulsar.
Step 1: make sure you’re detecting ‘em.
Step 2: detect ‘em a few times over many months
Step 3: build timing solutions and load them into the D4 database.
(brief parentheses – What’s TEMPO for?)
Towards a post-launch D4 database
DC2 Version 2 All Sky
Damien Parent ran his scripts over the new, improved V2 DC2 sky.
Flip through his 98 pages – it’s fun, they look great. Here’s page 96.
PSF cut done (“dist < 500/E”). Not big effect, investigating. Here, 3°cut.
Will study sensitivity & localisation.
About the 140 pulsars
(from Steve Thorsett transparencies)
Introduction to Nançay