Tuesday, March 22, 2005

Black Hole observations - The Bet and BH-PSRs

A long time ago, August 2002 in beautiful Chania, I rashly made The Bet. That by Feb 7th 2008, a black hole-pulsar system will be found (by implication through radio timing observations of the pulsar - there is a caveat that this is a discovery date, not confirmation, so bet may take till 2012 to settle.
Further, I bet (with no stakes) that the system will probably be found in a globular cluster (ah, but which one, that I'd like to figure out). Although the field (ie disk of the Milky Way) is a fair bet too.

For a black hole-pulsar system to be found in the galaxy, it has to be formed as a binary, with either a conventional black hole formed first, regular pulsar formed second system; or, a neutron star formed first, with a black hole formed second, after partially respinning-up the neutron star to a millisecond pulsar (probably not a very fast MSP). The latter is lower probability, but is longer lived, so odds of seeing either are probably comparable, and in the one-in-few-thousand range. And we're up to ~ 2000 known pulsars, so any decade now, modulo selection effects. cf this paper.

In a globular cluster, you could make such a system by exchange, and I discuss the processes semi-qualitatively in this paper. That could generally involve a proper MSP, and have some interesting orbital parameters. The goal obviously would be strong field tests of gravity, which would be cleaner, in general in the field, a cluster pulsar is more likely to have contaminated dynamics, but it would still be very interesting.

Anyway, somewhat rash bet, but always helps to provide some incentives to the observers, and if the Nobel prize won't do it then a good bottle of Bonny Doon Red certainly will.


Anonymous Anonymous said...

Gee, reading this I thought I would take that bet. Then I discovered that I already had. Must have gone heavy on the ouzo that night.

I have to admit that my confidence has been a bit shaken by the discovery of the double pulsar. I've never argued that there aren't any NS-BH binaries, just that we aren't going to find one with an active pulsar (and it will be pretty darn hard to find one otherwise). But the same arguments were made against finding NS-NS binaries with two active pulsars, and now one's been found. Leaves me feeling shakier, but still pretty confident.

Of course the Arecibo multibeam survey is just getting underway, so there will be plenty of new pulsars before Feb 2008. I'm hoping you win this one, Steinn -- and not just because you might share the wine.

--steve (sorry I can't figure out how to log in)

12:28 AM  
Blogger Steinn said...

Hey, are you allowed to admit these things now? If I'd known, I'd have invented suitable "odds". Anyway, Scott visited and reminded me so I made it official, Though I should probably have picked a more conservative date. If I concede, and the data later is shown to have been in the bag before the date, you can just pay me back two bottles!

Time for a push on some models on this one though, I think we can "predict" some orbital parameters and lifetimes and think about what can be tested. Specially in the clusters, and since Simon is already on it, might be time to hustle. Current interest is which clusters are a good bet (not that any decent observer should committ fully to a theoretical strategy, always hedge).

I think you have to be assimilated into Google blogspot to get a login ID, else you're anonymous.


12:34 AM  

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