The conference ended yesterday, and while there are a few remaining items to be tied up here, the post rate will drop to zero in a few weeks.
I want to thank the bloggers for this conference: Karl Smith, Nathalie Degenaar, Randy Cooper, Liliana Caballero, Nevin Weinberg, and Ed Cackett. They did an outstanding job of communicating the thrust of the conference with their live-blogging the sessions, pointing out goings-on around town and around the conference room. If you see one of them, shake their hand -- they were great.
Friday, May 22, 2009
Thursday, May 21, 2009
Rides to Albuquerque Thread
Driving to ALB? Add a comment below on what time you will be going to find riders. Need a ride at a certain time? Add a comment below giving the time you need to leave.
Homework Problems
Chuck began the discussion of homework.
* Multi-dimensional models for X-ray bursts. --> Connects nuclear experiment directly to astrophysical observer, the most distant line this community needs to cross. HS suggests the nuclear physics remains uncertain for multi-dimensional model, and therefore must pinned down.
* Lots of phenomenology from many different angles (define? what's an angle? - crust cooling, X-ray bursts, and code-to-code comparisons of X-ray bursts. BENCHMARK CASES with identical physics. This will be important with phase plots of NS mass and radius, with different constraints from different phenomena, one wants to be sure that the inputs at the microphysical level are identical.
*FYI: At Michael Smith's repository at nucastrodata.org, the whole community has access to the same primary dataset -- this is intended to act as a benchmark.
* FYIDuncan Galloway's X-ray burst lightcurve repository is a resource for the modeling community.
* Modelling the crust: is it amorphous or crystaline, and do magnetic field evolution affect the the crust. A model of the magnetic field evolution with amorphous conductivity, to see if the crust blows up.
* Make magnetic field evolution models a community resource.
* FYI: European Compstar will provide codes for students for neutron structures, NS rotation, supernova hydrodynamical codes.
* FYI: JINA has a series of schools, dedicated to giving away R-matrix code to analyse reaction codes; some network codes; shell model.
* Wiki for this conference.
* Who are all these people? What do they do? How do I know who does what? It seems important to see the expertise in the field in a plainer way.
* The Wasserman Question: Where are the condensed matter people in all this? For example, they have been working with rotation in superfluid 3He for some time, they must be able to inform our understanding of rotation in neutron stars. We need to do outreach to condensed matter physicists, who study superfluidity and strong magnetic fields in matter, because they were not represented at this workshop.
* Gravitational work will continue to grow in importance to neutron stars. We should be embedding them with us, as soon as possible.
* Multi-dimensional models for X-ray bursts. --> Connects nuclear experiment directly to astrophysical observer, the most distant line this community needs to cross. HS suggests the nuclear physics remains uncertain for multi-dimensional model, and therefore must pinned down.
* Lots of phenomenology from many different angles (define? what's an angle? - crust cooling, X-ray bursts, and code-to-code comparisons of X-ray bursts. BENCHMARK CASES with identical physics. This will be important with phase plots of NS mass and radius, with different constraints from different phenomena, one wants to be sure that the inputs at the microphysical level are identical.
*FYI: At Michael Smith's repository at nucastrodata.org, the whole community has access to the same primary dataset -- this is intended to act as a benchmark.
* FYIDuncan Galloway's X-ray burst lightcurve repository is a resource for the modeling community.
* Modelling the crust: is it amorphous or crystaline, and do magnetic field evolution affect the the crust. A model of the magnetic field evolution with amorphous conductivity, to see if the crust blows up.
* Make magnetic field evolution models a community resource.
* FYI: European Compstar will provide codes for students for neutron structures, NS rotation, supernova hydrodynamical codes.
* FYI: JINA has a series of schools, dedicated to giving away R-matrix code to analyse reaction codes; some network codes; shell model.
* Wiki for this conference.
* Who are all these people? What do they do? How do I know who does what? It seems important to see the expertise in the field in a plainer way.
* The Wasserman Question: Where are the condensed matter people in all this? For example, they have been working with rotation in superfluid 3He for some time, they must be able to inform our understanding of rotation in neutron stars. We need to do outreach to condensed matter physicists, who study superfluidity and strong magnetic fields in matter, because they were not represented at this workshop.
* Gravitational work will continue to grow in importance to neutron stars. We should be embedding them with us, as soon as possible.
At Crust09: on the roof
It's near the end of the morning coffee break on Thursday, and the workshop is almost done. Seems we're still enjoying it.
Victoria Kaspi: Anomalous X-ray Pulsars
Vicky kicked off the fourth and final day of the workshop by reviewing the observational properties of anomalous X-ray pulsars (AXPs). AXPs form a class of highly magnetized neutron stars, denoted as magnetars, together with soft gamma repeaters (SGRs).
Vicky showed the results of phase-coherent timing studies of 5 AXPs (SGRs are too faint to detect with RXTE when not bursting or flaring) using a long-term monitoring program with the RXTE satellite.
The AXPs appear to display many glitches; sudden spin-up events that may be explained by a faster rotating crustal superfluid suddenly transferring angular momentum to the crust. Glitch studies can possibly help to constrain the superfluid properties of neutron stars. The AXP glitches are rather peculiar compared to those observed from rotation powered pulsars and sometimes result in a net spin-down rather than an increase in the spin period.
Check out the online magnetar catalog if you are looking for information on one of the AXPs or SGRs.
In Santa Fe: Another night at the pool
Credit: Erik KuulkersGosh, doesn't he play pool like he does science?!
Wednesday, May 20, 2009
In Santa Fe: Quotations
"Magnetars are hopeless." Anonymous, in response to the question "what did we learn from this workshop?"
"I just don't want to be quoted on any blogs." Erik Kuulkers
"It was accepted? Oh shit!" Andrew Steiner, in reference to his credit card.
"It's almost as contentious as horse jokes." Ed Brown
"I just don't want to be quoted on any blogs." Erik Kuulkers
"It was accepted? Oh shit!" Andrew Steiner, in reference to his credit card.
"It's almost as contentious as horse jokes." Ed Brown
Coming Talks: Thursday May May 21
| Victoria Kaspi | Anomalous X-ray Pulsars | 9:00 |
| maxim Lyutikov | Evolution of magnetic fields in magnetars | 9:45 |
| Roberto Turolla | Currents in magnetar magnetospheres | 10:10 |
| Jose Pons | Thermal Evolution of Magnetars | 11:00 |
| Steve Price | Thermo-Resistive Instability in Magnetar Crusts | 11:45 |
| Rishi Sharma | Superfluid Heat Conduction in Magnetars | 12:10 |
| Bob Rutledge, Hendick Schatz | Getting Organized to make the case for future experiments to studyneutron stars. | 2:10 |
Andrew Steiner: Elucidating the properties of dense matter from starquakes in neutron star crusts
Andrew told us about how oscillations detected in magnetar giant flares may quantitatively constrain nuclear physics, in particular the ubiquitous nuclear symmetry energy. The symmetry energy is one of the largest uncertainties of the crust parameters; this uncertainly leads to uncertainties in the shear modulus and shear speed.
Interestingly, Andrew suggested that the traditional mode assignments to the crust and core modes may be incorrect. If true, this could explain the implied magnetar mass of less than one solar mass: The actual mass could be higher, which would help many at the workshop sleep better.
Interestingly, Andrew suggested that the traditional mode assignments to the crust and core modes may be incorrect. If true, this could explain the implied magnetar mass of less than one solar mass: The actual mass could be higher, which would help many at the workshop sleep better.
Nils Andersson: Modeling realistic crust dynamics
Nils convinced us that non-magnetic relativistic model is not good enough to describe torsional oscillations of NS. Improvement could be done by including crust-core coupling. His model uses relativistic multi-fluid equations of motion. He also includes elasticity of the fluids and the effect of magnetic field. His model depends on several aspects. For example, this model requires a detail understanding of the superfluid in the crust. Nils also need to know how smooth is the transition from the crust to the core. Another key ingredient is the vortex dynamics.
One of the main aspects Nils pointed out is the connection between the microphysics and the mesoscopic scale,e.g if you a particular nuclear pasta shape, how this would behave if its dimensions is of the order of cm.
One of the main aspects Nils pointed out is the connection between the microphysics and the mesoscopic scale,e.g if you a particular nuclear pasta shape, how this would behave if its dimensions is of the order of cm.
Yuri Levin: MHD aspects of magnetar oscillations
Magnetar quasi-periodic oscillations (QPO's) would be relatively easy to model, and thereby deduce properties of neutron stars, if all we needed to worry about is the crust. If only it were that easy.
There are two types of torsional modes in the neutron star: shear modes in the crust and alfven modes in the core. These two modes have similar frequencies, so we expect coupling between the modes. The timescale for energy exchange is much smaller than the duration of the QPO's, so we expect many exchanges to occur.
Therefore, we need a realistic model of the coupled crust and core to really understand magnetar QPO's.
There are two types of torsional modes in the neutron star: shear modes in the crust and alfven modes in the core. These two modes have similar frequencies, so we expect coupling between the modes. The timescale for energy exchange is much smaller than the duration of the QPO's, so we expect many exchanges to occur.
Therefore, we need a realistic model of the coupled crust and core to really understand magnetar QPO's.
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