Millisecond Pulsar Ages

[...link: astro-ph...]

Implications of Binary Evolution and a Maximum Spin Frequency

 

In the absence of constraints from the binary companion or supernova remnant,the standard method for estimating pulsar ages is to infer an age from the rate of spin-down. While the generic spin-down age may give realistic estimates fornormal pulsars, it can fail for pulsars with very short periods. Details of the spin-up process during the low mass X-ray binary phase pose additional constraints on the period (P) and spin-down rates (Pdot) that may consequently affect the age estimate. Here, we propose a new recipe to estimate millisecond pulsar (MSP) ages that parametrically incorporates constraints arising from binary evolution and limiting physics. We show that the standard method can be improved by this approach to achieve age estimates closer to the true age whilst the standard spin-down age may over- or under-estimate the age of the pulsar by more than a factor of ~10 in the millisecond regime.

We use this approach to analyze the population on a broader scale. For instance, in order to understand the dominant energy loss mechanism after the onset of radio emission, we test for a range of plausible braking indices. We find that a braking index of n=3 is consistent with the observed MSP population. We demonstrate the existence and quantify the potential contributions of two main sources of age corruption: the previously known "age bias" due to secular acceleration and "age contamination" driven by sub-Eddington progenitor accretion rates. We explicitly show that descendants of LMXBs that have accreted at very low rates will exhibit ages that appear older than the age of the Galaxy. We further elaborate on this technique, the implications and potential solutions it offers regarding MSP evolution, the underlying age distribution and the post-accretion energy loss mechanism..

 

Ages

MSP age

MSP age2

where the critical magnetic field is Bc~3.3*10^8 G for a putative mass shedding limit Psh~1ms, and alpha=2.58*10^6 (s^4/7).

Millisecond Pulsar Evolution

[...Movie: 2.8 MB...]

MSP Movie Kiziltan

[...Click on the image for full resolution color movie...]

 

Abstracts

  • Redefining Millisecond Pulsar Ages, Kızıltan & Thorsett, 214th American Astronomical Meeting, Vol. 41, p.699 (+Press conference) (2009)
  • Constraints on Millisecond Pulsar Evolution, Kızıltan & Thorsett, 213th American Astronomical Meeting, 213-L-2291 (2009)
  • Pulsar Evolution: A New Perspective, Kızıltan & Thorsett, National Society of Black Physicists/National Society of Hispanic Physicists Conference (2009)
  • “Connecting the Current with the Past: The Spin-Down Evolution of Millisecond Pulsars”, Kızıltan & Thorsett, “40 YEARS OF PULSARS: Millisecond Pulsars, Magnetars and More. AIP Conference Proceedings, Volume 983, pp. 639-641 (2008)
  • Neutron Star Physics in the GLAST Era, Kızıltan & Thorsett, 40 YEARS OF PULSARS: Millisecond Pulsars, Magnetars and More. AIP Conference Proceedings, Volume 983, pp. 639-641 (2008)
  • The Distribution of Ages, Magnetic Fields and Spin Period Periods of Millisecond Pulsars, Kızıltan & Thorsett, 209th American Astronomical Society Meeting, Vol. 38, p.1065 (2007)
  • Pulsar Mass Measurements, Kızıltan & Thorsett, Texas in Australia: XXIII Meeting on Relativistic Astrophysics (2006)
  • Pulsar Physics with GLAST, Kızıltan & Thorsett, Texas in Australia: XXIII Meeting on Relativistic Astrophysics (2006)
  • Neutron Star Physics with GLAST, Kızıltan, Thorsett, GLAST/LAT Team, 36th COSPAR Scientific Assembly Meeting: Plenary Meeting, 2114 (2006)
  • The Distribution of Magnetic Fields, Ages and Spin Periods of Millisecond Pulsars, Kızıltan, Thorsett, Camilo, 36th COSPAR Scientific Assembly: Plenary Meeting, 2155 (2006)
  • Pulsar Astronomy with GLAST, Kızıltan & Thorsett, Heraeus Meeting: Neutron Star, Pulsars & Supernova Remnants (2006)
  • Pulsar Mass Measurements, Kızıltan & Thorsett, Heraeus Meeting: Neutron Star, Pulsars & Supernova Remnants (2006)
  • The Distribution of Ages, Magnetic Fields and Spin Period Periods of Millisecond Pulsars,Kızıltan & Thorsett, Heraeus Meeting: Neutron Star, Pulsars & Supernova Remnants (2006)
  • Pulsar Astronomy with GLAST, Kızıltan & Thorsett, “A Life with Stars” (New Astronomy Reviews, Elsevier), eds. Kasper, Van der Klis, Wijers (2005)
  • Pulsar Mass Measurements, Kızıltan & Thorsett, “A Life with Stars” (New Astronomy Reviews, Elsevier), eds. Kasper, Van der Klis, Wijers (2005)
  • Neutron Star Physics with GLAST, Kızıltan & Thorsett, “Neutron Stars at Crossroads” meeting (2005)
  • Pulsar Mass Measurements, Kızıltan & Thorsett, “Neutron Stars at Crossroads” meeting (2005)