Crosstalk

E. Cackett: Crustal cooling in accretion heated neutron stars.
Quasi persistent sources provide a rare opportunity to observe crustal cooling ... and we think we've measured the thermal relaxation time of the crust in 2 sources.

A. Steiner: Symmetry energy, crust thickness and KS 1731.
The physics of neutron star crusts is very thorny, the theorist have much work to do, yet we are a vibrant community which is making progress! Keep the observations coming, contact us with questions or concerns anytime. Don't give in to dark energy.

N. Sandulescu: Nuclear Superfluidity and Cooling Time of Neutron Star Crust.
No conclusions but in summary: Pairing in the crust can significantly change the thermal diffusion time.

C. Heinke: Constraints on Neutron Star Physics from Transiently.
Accreting Neutron Stars in Quiescence.
Messages:

• Zero-B hydrogen-atmosphere models are trustworthy.

• M,R constraints from neutron stars in globular clusters are sound and getting interesting
  

• Cooling rates for soft x-ray transients are strictest constraints and disallow minimal cooling.

Questions:

• What range of nuclear EOS are considered reasonable.

K. Levenfish: Thermal steady-states of neutron stars in soft X-ray transients vs deep crustal heating.
Proton superfluidity is strong in the core and neutron superfluidity weak.

E. Brown: Crust electron captures: Implications for superbursts and transient lightcurves.
For the nuclear physicists:
Transport properties: what is the thermal conductivity of pasta (and sauce) - are there reasonable upper and lower limits. Need better understanding of the crust/core interface.

For the astrophysicists
Need larger sample of superburst and burst at low accretion rates. Synthesis of disparate observations: isolated cooling neutron stars, magnetars, X-ray bursters, X-ray transients share the same nuclear physics.

S. Reddy. Weak interactions in superfluids and cooling rates in the inner crust.
Neutrino rates in matter can differ by factors of a few but if larger factors are proposed - be skeptical - ask lots of questions.

Forget about about PBF in the vector channel.

J. Dey: Stellar and terrestial observations from the mean field large colour QCD models.
For astrophysicists: Observations are good.
For nuclear model people: u r doing well.
For phenomenologist like us the message is: look for discrepancies and try simple QCD models.

Tomorrow's Talks

9:00. Jean in' t Zand. Observations of Rare and Peculiar X-ray Bursts.
10:00. Randy Cooper. Generation of Type 1 X-ray Burst Oscillations.
11:00. Erik Kuulkers. INTEGRAL Galactic Bulge Monitoring Program
12:00. Fang Peng. Weak Hydrogen-Powered Explosions on Accreting Neutron Stars.
2:00. Andrew Cumming. Nuclear Burning on Accreting Nuetron Stars.
3:00. Sudip Bhattacharyya. Probing Neutron Star Physics Using Thermonuclear X-ray Bursts.
4:00. Discussion.
Conference Close.

Tomorrow's Talks

9:00. Ed Cackett. Crustal Cooling in Accretion Heated Neutron Stars.
10:00. Andrew Steiner. Symmetry Energy, Crust Thicknesses, and KS 1731-260.
11:00. Nikolai Sandulescu. Nuclear Superfluidity and Cooling Time of Neutron-Star Crust.
11:30. Craig Heinke. Constraints on Neutron Star Physics from Transiently Accreting Neutron Stars in Quiescence.
12:00. Kseniya Levenfish. Thermal Steady-States of Neutron Stars in SXTs vs. Deep Crustal Heating.
2:00. Ed Brown. Crust Electron Captures: Implications for Superbursts and Transient Lightcurves.
3:00. Sanjay Reddy. Weak Interactions in Superfluids and Cooling Rates in the Inner Crust.
3:30. Jishnu Dey. Stellar and Terrestrial Observations from the Mean Field Large Colour QCD Models.
4:30. Discussion.

Crosstalk

Vicky Kaspi. Magnetars. For nuclear theorists: Magnetars may have relevance to the EOS.

Anna Watts. Magnetar Seismology. For nuclear theorists: If we really are seeing NS starquakes, then we have a fantastic new probe of crust physics. Also, I would like to know:
* How and when the Crust yields
* The Shear Modulus of your favorite crust models
* What precisely is going on at the crust/core boundary.

Jeremy Heyl. QED Can Explain the Non-Thermal Emission from SGRs and AXPs.
For Nuclear Theorists: Does nuclear material have a gap? I don't care whether it's 0.5 or 2 MeV.
* Is the proton superconductor Type I or Type II? If Type II, do currents along vortices make it act like Type I?
* Where is the quark-hadron phase transition? Sure the quark phase has lots of structure, but it may be completely irrelevant.

For Observational Astronomers:
* Should I really believe these lines, periods, Pdots, error bars?
* Rare systems are great! Get me more? How about some eclipsing binaries in globular clusters, or really young cooling neutron stars.
* Coordinated timing campaigns as BATSE did for accreting neutron stars.


Roberto Turolla. X-ray Spectra from Magnetar Candidates.
For nuclear theorists: It would be a great help to have a detailed model of the corona of the magnetosphere.


Silvia Zane. SGRs Long Term Spectral Variability.
For Nuclear Theorists: I would like to understand better the effect of a strong magnetic field on the interior of the neutron star.

Equation of State from Heavy Ion Collisions

"If Bill Lynch were here..." - Madappa Prakash

There is much effort going in to determining the equation of state of matter (and the density dependence of the symmetry energy) in the heavy-ion community (of which Bill is an integral part). Heavy-ion collisions can potentially determine the EOS up to possibly a few times saturation density and Bill's famous Science paper is here. I (along with others) spoke a bit about this in Catania (EXOCT'07), but will not have time to do so here. For those of you who are interested, there is a simple and brief discussion about heavy-ion collisions in Jim and Prakash's recent contribution to the Hans Bethe volume.

- Andrew Steiner

a glossary for neutron star physics

I find that it is a very nice idea to bring together neutron star observers, astrophysicists and nuclear physicists. It is a very rare opportunity to discuss
but I think that it may be even better to try to write up a short glossary of the present terminology used in the field. This is of course constantly renewing, mainly for the observational part, new objects are discovered, new classes show up, ... But it could be of interest for our communication to define the 20-30 items mostly used and have 5 lines of description. It would fix the 2007 terminology and could be renewed every year.
In practice, the idea would be that each of the participants contribute to 1 item during the workshop, then we collect all the items, built a glossary, and that's done !

Tomorrow's Talks

9:00. Vicky Kaspi. Magnetars
10:00. Anna Watts. Magnetar Seismology
11:00. Jeremy Heyl. QED Can Explain the Non-Thermal Emission from SGRs and AXPs.
11:30. Roberto Turolla. X-ray Spectra from Magnetar Candidates.
12:00. Silvia Zane. SGRs Long Term Spectral Variability.
12:30. David Eichler. What Can We Learn about Magnetar Crusts from the QPO Component of their Flare Emission? (Withdrawn).

My notes on a wiki

Hi,

I have been taking notes on the talks on my wiki at the following URL

http://tabitha.phas.ubc.ca/wiki/index.php/INT_-_Neutron_Star_Crust_and_Surface

that others might find useful.   

Jeremy

Crosstalk

Chuck Horowitz: Neutron Rich Matter and Neutron Star Crusts.
To observational astronomers: Astronomers should ask nuclear physicists two questions: (1) Are your results model dependent. and (2) What are your theoretical error bars?


Jorge Piekarewicz:The Impact of Terrestrial Facilities on the Structure of the Neutron Star Crust
To observational astronomers: The new facilities (like RHIB) will constrain the low density EOS. We need nice neutron star M-R measurements to constrain the high-density EOS, and the observational astronomy approaches are the only ones I know which can produce these constraints.


Jim Lattimer: Observational Constraints on the Neutron Star Crust and their Implications for the Dense Matter Equation of State.
We desparately need a radius measurement, even without a mass measurement, because it can provide a reasonable constraint on the EOS.

K. Sato: Nuclear "Pasta" Phases by Quantum Molecular Dynamics.

To observational astronomers: It would be very valuable to have observational constraints on what densities the pasta phase occurs [ed.: it is noted that this will be difficult, since it is not yet clear what observable can provide a unique signature of the pasta phase.]


Bennet Link. The Dynamics of Vortex Pinning in the Neutron Star Crust.
To observational astronomers: Please identify rotational and seismic modes (observationally!).
To Nuclear Theorists: fully solve the vortex/nucleus interaction problem.

Steve Price. Time-correlated Structure in Spin Fluctuations of an Isolated Neutron Star.
To nuclear theorists: In the future, we will assume some physical value for the torque, and be able to constrain the value of the reduce the moment of inertia. This should constrain the ratio of the core moment of inertia to that of the crust.

Alex Turbiner. One-Two Electrons Atomic-Molecular Systems in a Strong Magnetic Field.
To observational astronomers: At B-fields between 1e12 and 4.4e13 G of two-electron systems, all basic transitions, dissociations and ionization energies have energies between 100-1000 eV.


Marcello Baldo. Microscopic Theory of the Neutron Star Inner Crust.
To observational astronomers: We can calculate in a reliable way the Equation of State of the crust (pressure vs. density); however, the more detailed physics (such as the shear modulus) is still not well known.


Jerome Margueron. Equation of State in the Inner Crust of Neutron Matter: Discussion of the Finite Size Effects. What is interesting in thisese models is the impact on predictions regarding cooling processes (see talk by N. Sandulecu).

Chris Fryer. After the Shock, Magnetic Fields and Fallback on Newly Formed Neutron Stars.
To observational astronomers: Anything you can tell me about Cas A (is it a magnetar?) will help me constrain SNe models. To nuclear physicists: are there any effects of fallback on nucleosynthetic yields?


Aimee Hungerford. Neutrino Scattering in Proto-Neutron Stars.
To observational astronomers: Self-regulation was a bit of surprise to us, but it seems one cannot learn very much about the interior equation of state from neutrino observations.

Blogging and Relevancy

I'd like to point out that, so far, there haven't been any posts by anyone other than myself -- some for information, some for commentary.

But I've heard about 4-5 different people say "We should have a discussion about XX" on various subjects. While it's reasonable to want to have the discussion live-time, this is actually the perfect form to start such discussions. As I've written before, this blog is open to any topic of any type related to the workshop. Twenty-two of the conference goers -- about half -- have signed on.


Update: All program participants and conference attendees should have received (by email) an invitation to be able to post. If you have not, send me an email.

Today's Talks

Today's Talks for the workshop conference:


9:00. Chuck Horowitz. Neutron Rich Matter and Neutron Star Crusts

10:00. Jorge Piekarewicz. The Impact of Terrestrial Facilities on the Structure of the Neutron Star Crust

11:00. Jim Lattimer. Observational Constraints on the Neutron Star Crust and their Implications for the Dense Matter Equation of State.

12:00. Katsuhiko Sato. Nuclear "Pasta" Phases by Quantum Molecular Dynamics.

2:00. Bennet Link. The Dynamics of Vortex Pinning in the Neutron Star Crust.

2:30. Steve Price. Time-correlated Structure in Spin Fluctuations of an Isolated Neutron Star.

3:00. Alex Turbiner. One-Two Electrons Atomic-Molecular Systems in a Strong Magnetic Field.

4:00. Marcello Baldo. Microscopic Theory of the Neutron Star Inner Crust.

4:30. Jerome Margueron. Equation of State in the Inner Crust of Neutron Matter: Discussion of the Finite Size Effects.

5:00. Chris Fryer. After the Shock, Magnetic Fields and Fallback on Newly Formed Neutron Stars.

5:30. Aimee Hungerford. Neutrino Scattering in Proto-Neutron Stars.

Crosstalk

Throughout the conference, I am asking all observational astronomers, "What single most important fact do you want our nuclear theorist colleagues to take away from your talk?". Also, I am asking all nuclear theorists the similar question, what observational astronomers should take away from their talks.

This is the compendium of responses from the first day.

David Kaplan:
To nuclear theorists: Things are a lot more complicated than we thought five or ten years ago, but we are making progress and learning a lot.

Slava Zavlin: X-ray emission from the young pulsar J1357-6429 and similar objects.
To nuclear theorists: Be cautious in interpreting numbers from observations. There are many systematic uncertainties.

Dong Lai: Surfaces of Magnetic Neutron Stars.
To nuclear theorists: There is a lot of interesting physics to be explored regarding the condensed surfaces of neutron stars.

Eric Gotthelf: CCO pulsars as anti-magnetars: Evidence of Neutron stars Weakly Magnetized at Birth.
To nuclear physicists: Emission mechanisms for CCOs, magnetars and INSs are something which we don't understand, and what we need to know, to explain these classes of NSs jointly.

H.-J. Schulze: Pairing Gaps in Neutron Star Matter.
To observational astronomers:
Polarization effects suppress the BCS gaps. This will impact cooling, and observations of glitches.

Achim Schwenk: Superfluidity in neutron stars.
To observational astronomers:
1. There are many developments attempting S-wave pairing.
2. Neutrons may not be superfluid in the core.
3. Nuclear Theory is now trying to do calculations without model dependence, but including systematic uncertainties.
4. I would like to know what observational constraints exist on pairing in superfluid neutrons.

Enrico Vigezzi. Pairing Calculations Beyond Mean Field in the Inner Crust.
To observational astronomers:
1. Listen to the next talk (Barranco).
2. The specific heat in superfluid neutrons can be influenced due to the presence of nuclear clusters, by 1-2 orders of magnitude.
3. Be cautious about the local density approximation.

F. Barranco: Microscopic Calculations of Vortex-Nucleus Interaction.
To observational astronomers:
1. The pinning energy is not negative at > 0.03 fm-3 as previously thought; it is apparently positive.
2. Consequences in terms of glitch properties will be discussed by Bennet Link tomorrow. But, pinning is simply much less likely, only very weakly, and in a much smaller volume. Bennet will argue that pinning is very difficult to ever occur in this scenario. In other words, pinning would have nothing to do with glitches in the crust.

Joe Carlson. Pairing gaps in low-density neutron matter and cold atoms
To observational astronomers:
A question: The laboratory experiments using cold atoms will solve the problem of low density s-wave pairing caps -- is that useful in an astrophysical setting?