Compact Object Panel Presentations for Bethe Symposium Brad Hansen (UCLA): White Dwarfs Lars Bildsten (KITP, UCSB): Type Ia Progenitors Chris Thompson (CITA): Magnetars and Pulsars Chris Reynolds (U. Maryland): Black Holes

PN image from HST Ring Nebulae (M 57) HST Young White Dwarf

WD ages and masses found via spectroscopy (e.g. Reid ‘96), while open cluster age is found via Main Sequence fitting and/or lithium depletion, difference between the two gives age of the star that made the WD and hence INITIAL mass. WDs in Open Clusters Claver et al. ‘01 ==> WD Masses are set by the core mass at the time of the first thermal pulse on the AGB (shown here by dotted and dashed lines)

Piro ‘05

Type Ia SN are a diverse population resulting from the disruption of 1.3 solar mass C/O WDs, producing solar masses of 56Ni They occur in both >10 Gyr and < 1 Gyr stellar populations, fainter ones in old population, brightest in young populations Light-curves and nucleosynthesis point to central ignitions followed by burning outwards (some say deflagrate all the way, some say detonate at a later stage) WD mergers occur and cause off-center ignitions, most feel this makes a nice neutron star, not a Ia SN Central ignition prefers accretion at low rates, where H and He burn unstably... What we Know about Accreting White Dwarfs to Ia Supernovae

The brightest manifestations of the mass transfer are the thermonuclear ignitions of accreted shells of matter (Novae!) or steady burning (Supersoft sources)=> We must learn if these systems are adequate in number! (CVs are not) What’s the physics (central density at ignition and weak interactions?) that explains the diversity of 56Ni mass? Why is the 56Ni mass lower from the old population? Does the metal content (really 22Ne) actually matter. Naively the range of 22Ne content can be a factor of 5! Observe a WD merger that does not yield a Ia SN (I.e. theory needs to make testable predictions of merger visibility) We Hope to identify the progenitors IMPLIED by Central Ignitions!

Hydrogen Accreting Binaries Townsley & Bildsten 2005 Supersoft Sources: Burn H Stably (van den Heuvel et al 1992), or Symbiotics/RN Cataclysmic Variables undergo unstable burning, leading to Classical Novae. Whether the mass stays or goes is uncertain Accumulated mass The WD masses are not known

Stritzinger et al, ‘05, astroph/ bg and 1999de in E/SO galaxies Light Curve Fitting to Measure Ejected and 56Ni Masses

Magnetars

(Unrecycled) Radio Pulsars and Magnetars Spindown: B dipole ~ G (magnetic dipole approx.) X-ray absorption features in Dim Isolated N.S. X-ray lines in SGR flares (?) + SGR flare physics Tests: Magnetic field decay in AXPs/SGRs: SGR giant flares --> B  ~ (N burst /100) 1/2 G 0.1-second SGR-like bursts from AXPs L X ~ L spindown in AXPs L X (non-thermal) ~ 10 L X (thermal)  magnetospheric Thermal X-rays: L X (AXP) ~ 10 2 L X (Vela) High - T b electromagnetic emission: AXPs: L optical/IR ~ L spindown !! (but L radio ~ L spindown for some pulsars) Emission mechanisms bunching + curvature Langmuir --> ordinary mode Transient: Persistent: (as expected for |  e +  p -  n | ~ kT)

Neutron stars have crusts: Pulsar glitches: I superfluid ~ I crustal neutrons ~ I neutron star SGR bursts: dN/dE ~ E -1.6 ; creeping behavior energy > ergs  yield strain > 0.03 (!) Superfluid components - glitches: Pulsars: I sf ~ I NS AXPs: I sf > 0.1 I NS (if  sf >  crust ) but magnetically triggered Red ``timing noise’’ Radio pulsars: generally non-periodic (but PSR ) electrodynamic ? superfluid creep ? precession / polar wandering? SGRs/AXPs: huge (x 4 !) long-term (> 4 yr) increases in torque somewhat correlated with bursting activity  electrodynamic (non-potential magnetosphere)

SOME AVENUES FOR FUTURE PROGRESS Constrain neutron pairing temperature in N.S. core: T cn ~ 5x10 8 K can help explain L X,thermal (AXP) ~ 10 2 L X,thermal (Vela) P magnetar ~ 5-12s --> e + e - death line? Magnetic field decay in (non-binary) radio pulsars? Sweeping of superconducting fluxoids in core (Ruderman) Hall drift B  ~ 3x10 14 G --> L X ~ ergs/s over 10 6 yrs

Black Holes: highlights of current state of knowledge Stellar motions around Galactic Center Black hole induced ICM disturbances in the Perseus galaxy cluster Relativistic effects from spectrum of central accretion disk BHs are common! >25 Galactic BH candidates Massive BHs found in all major galaxies Mounting evidence for “Intermediate” mass BHs BHs impact their environment Tight relation between host galaxy and BH mass BHs implicated in shaping of galaxy mass function BH jets impact intracluster gas in galaxy clusters X-ray data probe strong GR effects Spectroscopy of accretion disk reveals strong gravity effects Seen in AGN and stellar- mass BH systems Also, X-ray timing…

Black Holes: future directions Distribution of disk temps for IMBH candidates Hubble Deep Field Cosmic history of BHs? Exactly which stars form stellar-mass BHs Are intermediate mass BHs real? How do they form? How do massive BHs form? Are IMBH the seeds? Effect of BHs on galaxy formation? Do black holes REALLY have a major impact on galaxy formation? What physics is at work in this feedback? Is GR correct close to BH horizon? Detailed X-ray spectroscopy & timing Gravitational wave experiments Demographics of BH spin

17 Black Hole Dynamical Masses span the range up to 20 solar masses Neutron Star masses now more diverse, especially helped by the 1.25 in PSR J Mass distributions are showing the diversity we expect from complications of core collapse and fall-back J. Orosz compilation Maximum Neutron Star Mass