Transcript Radio Frequency Interference Mitigation in the Arecibo ALFA Pulsar

The Radio Millisecond Pulsar
PSR J1023+0038:
A Link to Low-Mass X-Ray Binaries
Slavko Bogdanov
Rotation-powered millisecond pulsars
 Spun-up (“recycled”) by accretion of
mass and angular momentum in lowmass X-ray binaries
 Most are in binaries with white dwarf
or very low-mass (~0.03 M)
degenerate companions
 To date, no accreting X-ray MSP (e.g.
SAX J1808.4–3658) has been seen to
turn on as a radio pulsar
SDSS J102347.6+003841 / PSR J1023+0038

V ~ 17.5 magnitude star with a solar-type
spectrum and mild 0.198-day orbital
variability

X-ray counterpart with non-thermal
spectrum – classified as quiescent lowmass X-ray binary (Homer et al. 2005)

1.69-ms (“recycled”) rotation-powered
radio pulsar in 0.198 day circular binary
orbit with ~0.2 M companion,
discovered in Green Bank Telescope
drift scan survey (Archibald et al. 2009)

Deep radio eclipse near superior
conjunction + random/irregular eclipses
throughout orbit

First known radio MSP in the field of the
Galaxy with non-degenerate companion
star (several similar systems in globular
clusters)

First radio MSP to exhibit evidence for
an accretion disk (Wang et al. 2009)
Archibald et al. (2009)
2000-2001: Evidence for an Accretion
Disk



Optical observations from May 2000 - Dec.
2001: blue spectrum with prominent emission
lines & rapid flickering by ~1 mag
Double-peaked (asymmetric) emission lines –
a hot accretion disk?
Simple disk model:
–
–
–
No X-ray observations during 2000-2001

No evidence for disk or emission lines since
May, 2002
Neutron star is currently a radio pulsar with a
rotation-powered relativistic wind
Companion may still be Roche lobe filling
Optical variability due to irradiation of face of
secondary star by pulsar wind.


H
temperature range of 2000–34000 K,
disk inner and outer radii of 109 and 5.7×1010 cm
disk mass ~1023 g


Wang et al. (2009)
System transitioning between
LMXB and recycled rotation-powered pulsar?
2009-2010: X-ray Variability + Pulsations
Archibald et al. (2010)
XMM-Newton EPIC pn
0.25-2.5 keV
Chandra ACIS-S
1.4 GHz
Bogdanov et al. in prep.
Or at Binary Period
X-ray Variability
PSR J1740–5340
(NGC 6397)
PSR J1023+0038
Bogdanov et al. in prep
PSR J0024–7204W
(47 Tuc)
Bogdanov, Grindlay, & van den Berg (2005)
Bogdanov et al. (2010)
X-ray and Optical Variability
 X-ray variability due to interaction of relativistic pulsar wind and matter
from secondary star – intrabinary shock
 X-ray pulsations due to heating of polar caps by magnetospheric return
current or non-thermal magnetospheric emission
PSR J1740–5340
Credit:ESA/F.Ferraro
Summary
• PSR J1023+0038: First radio millisecond pulsar with
evidence for a past hot (accretion?) disk
• At present, J1023+0038 is a “recycled” rotationpowered millisecond pulsar ablating its companion
• System can offer better understanding of close
binary evolution, especially transition from accretion
to rotation power – e.g. does SAX J1808.4-3658 turn
on as a radio MSP in quiescence?
•Site for studies of relativistic outflows and shocks
•Close optical/X-ray monitoring needed to catch
system in the “disk state”